Science.gov

Sample records for air side performance

  1. Air side thermal performance of wavy fin heat exchangers produced by selective laser melting

    NASA Astrophysics Data System (ADS)

    Kuehndel, J.; Kerler, B.; Karcher, C.

    2016-09-01

    Wavy fins are widely used for off-road vehicle coolers, due to their dust resistance. In this study, heat exchanger elements with wavy fins were examined in an experimental study. Due to independence of tooling and degrees of freedom in design, rapid prototyping technique selective laser melting was used to produce heat exchanger elements with high dimensional accuracy. Tests were conducted for air side Reynolds number Re of 1400-7400 varying wavy amplitude and wave length at a constant water flow rate of 9.0m3/h inside the tubes. The effects of wavy amplitude and wave length on the air side thermal performance were studied. Experimental correlation equations for Nu and ­ were derived by regression analysis.

  2. Experimental and numerical investigation on air-side performance of fin-and-tube heat exchangers with various fin patterns

    SciTech Connect

    Tang, L.H.; Zeng, M.; Wang, Q.W.

    2009-07-15

    Air-side heat transfer and friction characteristics of five kinds of fin-and-tube heat exchangers, with the number of tube rows (N = 12) and the diameter of tubes (D{sub o} = 18 mm), have been experimentally investigated. The test samples consist of five types of fin configurations: crimped spiral fin, plain fin, slit fin, fin with delta-wing longitudinal vortex generators (VGs) and mixed fin with front 6-row vortex-generator fin and rear 6-row slit fin. The heat transfer and friction factor correlations for different types of heat exchangers were obtained with the Reynolds numbers ranging from 4000 to 10000. It was found that crimped spiral fin provides higher heat transfer and pressure drop than the other four fins. The air-side performance of heat exchangers with the above five fins has been evaluated under three sets of criteria and it was shown that the heat exchanger with mixed fin (front vortex-generator fin and rear slit fin) has better performance than that with fin with delta-wing vortex generators, and the slit fin offers best heat transfer performance at high Reynolds numbers. Based on the correlations of numerical data, Genetic Algorithm optimization was carried out, and the optimization results indicated that the increase of VG attack angle or length, or decrease of VG height may enhance the performance of vortex-generator fin. The heat transfer performances for optimized vortex-generator fin and slit fin at hand have been compared with numerical method. (author)

  3. SOUTHEAST AND NORTHEAST SIDES. Looking west Edwards Air Force ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    SOUTHEAST AND NORTHEAST SIDES. Looking west - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Fuel & Water Tank, Test Area 1-115, northwest end of Saturn Boulevard, Boron, Kern County, CA

  4. SOUTH FRONT AND EAST SIDE. January, 1998 Edwards Air ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    SOUTH FRONT AND EAST SIDE. January, 1998 - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Electrical Substation, Test Area 1-115, northwest end of Saturn Boulevard, Boron, Kern County, CA

  5. Contemporary: The Psychological Side of Performance Improvement.

    ERIC Educational Resources Information Center

    Gerson, Richard F.

    2001-01-01

    Discusses the importance of focusing on the people side of performance improvement instead of just the models, processes, and theories. Topics include the mental state of the performer; the psychology of performance improvement; stress and its effects on performance; guaranteeing performance improvement; performance attributions; and external…

  6. Efficacy of side air bags in reducing driver deaths in driver-side collisions.

    PubMed

    Braver, Elisa R; Kyrychenko, Sergey Y

    2004-03-15

    Side air bags, a relatively new technology designed to protect the head and/or torso in side-impact collisions, are becoming increasingly common in automobiles. Their efficacy in preventing US driver deaths among cars struck on the near (driver's) side was examined using data from the Fatality Analysis Reporting System and the General Estimates System. Risk ratios for driver death per nearside collision during 1999-2001 were computed for head/torso and torso-only side air bags in cars from model years 1997-2002, relative to cars without side air bags. Confounding was addressed by adjusting nearside risk ratios for front- and rear-impact mortality, which is unaffected by side air bags. Risk ratios were 0.55 (95% confidence interval: 0.43, 0.71) for head/torso air bags and 0.89 (95% confidence interval: 0.79, 1.01) for torso-only air bags. Risk was reduced when cars with head/torso air bags were struck by cars/minivans (significant) or pickup trucks/sport utility vehicles (nonsignificant). Risk was reduced in two-vehicle collisions and among male drivers and drivers aged 16-64 years. Protective effects associated with torso-only air bags were observed in single-vehicle crashes and among male and 16- to 64-year-old drivers. Head/torso side air bags appear to be very effective in reducing nearside driver deaths, whereas torso-only air bags appear less protective.

  7. 15. BASE OF MST, SOUTHEAST SIDE, FACING SOUTHWEST. AIR COMPRESSOR ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    15. BASE OF MST, SOUTHEAST SIDE, FACING SOUTHWEST. AIR COMPRESSOR SHED AT STATION 3; PLATFORM AT STATION 12; ENVIRONMENTAL CURTAIN SWING AT STATION 21. ELECTRICAL HOOKUPS ON RIGHT SIDE OF PHOTOGRAPH. - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 East, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

  8. 6. Missile Alert Facility, west side. Thalheimer Whiteman Air ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. Missile Alert Facility, west side. Thalheimer - Whiteman Air Force Base, Oscar O-1 Minuteman Missile Alert Facility, Southeast corner of Twelfth & Vendenberg Avenues, Knob Noster, Johnson County, MO

  9. NORTHWEST FRONT AND SOUTHWEST SIDE, BUILDING 1933 Edwards Air ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    NORTHWEST FRONT AND SOUTHWEST SIDE, BUILDING 1933 - Edwards Air Force Base, X-15 Engine Test Complex, Observation Bunker Types, Rogers Dry Lake, east of runway between North Base & South Base, Boron, Kern County, CA

  10. 3. SOUTH SIDE. Edwards Air Force Base, South Base ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. SOUTH SIDE. - Edwards Air Force Base, South Base Sled Track, Firing & Control Blockhouse for 10,000-foot Track, South of Sled Track at midpoint of 20,000-foot track, Lancaster, Los Angeles County, CA

  11. 5. NORTH SIDE AND WEST REAR. Edwards Air Force ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. NORTH SIDE AND WEST REAR. - Edwards Air Force Base, South Base Sled Track, Firing & Control Blockhouse for 10,000-foot Track, South of Sled Track at midpoint of 20,000-foot track, Lancaster, Los Angeles County, CA

  12. 28. Main engine air pump located to port side of ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    28. Main engine air pump located to port side of main engine cylinder beside engine bed. Dynamo lies aft of air pump (at right), pipe at extreme left of image carries lake water to condenser valves. - Ferry TICONDEROGA, Route 7, Shelburne, Chittenden County, VT

  13. The People Side of Performance Improvement.

    ERIC Educational Resources Information Center

    Gerson, Richard F.

    1999-01-01

    Discusses 11 keys to the personal side of performance improvement, including positive attitude, high self esteem and positive self-image, communication skills, lifelong learning, caring about other people, health and well-being, motivation, goal setting, relaxation, visualization, and personal value system. (LRW)

  14. Air Quality Side Event Proposal November 2016 GEO XIII ...

    EPA Pesticide Factsheets

    The Group on Earth Observations (GEO), which EPA has participated in since 2003, has put out a call for Side Events for its thirteenth annual international Plenary Meeting which is in St. Petersburg, Russia this year during November, 2016. EPA has put on Side Events on Air Quality and Health observational systems at eight of the previous Plenaries. This document is a Side Event proposal regarding air quality, health and next generation monitoring and observations techniques. It is submitted to the GEO Secretariat for consideration. If accepted, there will likely be presentations by EPA and NASA, other GEO Member Countries and UNEP and other GEO Participating Organizations at the Side Event. It is an opportunity to share scientific and technological advances in this area and build partnerships and collaboration. The Group on Earth Observations (GEO), which EPA has participated in since 2003, has put out a call for Side Events for its thirteenth annual international Plenary Meeting which is in St. Petersburg, Russia this year during November, 2016. EPA has put on Side Events on Air Quality and Health observational systems at eight of the previous Plenaries. This document is a Side Event proposal regarding air quality, health and next generation monitoring and observations techniques.  It is submitted to the GEO Secretariat for consideration. If accepted, there will likely be presentations by EPA and NASA, other GEO Member Countries and UNEP and other GEO P

  15. Water Quality Performance of Three Side-by-Side Permeable Pavement Surface Materials: Three Year Update

    EPA Science Inventory

    Communities are increasingly installing structural low impact development (LID) practices to mange stormwater and reduce pollutant loads associated with stormwater runoff. Permeable pavement is a LID practice that has limited research on working-scale, side-by-side performance o...

  16. The Energy Implications of Air-Side Fouling in Constant Air Volume HVAC Systems

    NASA Astrophysics Data System (ADS)

    Wilson, Eric J. H.

    2011-12-01

    This thesis examines the effect of air-side fouling on the energy consumption of constant air volume (CAV) heating, ventilating, and air conditioning (HVAC) systems in residential and small commercial buildings. There is a particular focus on evaluating the potential energy savings that may result from the remediation of such fouling from coils, filters, and other air system components. A computer model was constructed to simulate the behavior of a building and its duct system under various levels of fouling. The model was verified through laboratory and field testing and then used to run parametric simulations to examine the range of energy impacts for various climates and duct system characteristics. A sensitivity analysis was conducted to determine the impact of parameters like duct insulation, duct leakage, duct location, and duct design on savings potential. Duct system pressures, temperatures, and energy consumption for two houses were monitored for one month. The houses' duct systems, which were both in conditioned space, were given a full cleaning, and were then monitored for another month. The flow rates at the houses improved by 10% and 6%. The improvements were primarily due to installing a new filter, as both houses had only light coil fouling. The results indicate that there was negligible change in heating energy efficiency due to the system cleaning. The parametric simulation results are in agreement with the field experiment: for systems in all eight climates, with flowrates degraded by 20% or less, if ducts are located within the thermal zone, HVAC source energy savings from cleaning are negligible or even slightly negative. However, if ducts are outside the thermal zone, savings are in the 1 to 5% range. For systems with flowrates degraded by 40%, if ducts are within the thermal zone, savings from cleaning occurs only for air conditioning energy, up to 8% in climates like Miami, FL. If ducts are outside the thermal zone, savings occurs with both

  17. Prediction of hydrodynamic performance of an FLNG system in side-by-side offloading operation

    NASA Astrophysics Data System (ADS)

    Zhao, Wenhua; Yang, Jianmin; Hu, Zhiqiang; Tao, Longbin

    2014-04-01

    Floating liquefied natural gas (FLNG) is a type of liquefied natural gas (LNG) production system that shows prospects in exploitation of stranded offshore gas fields. The dynamic performance of an FLNG system in side-by-side configuration with a LNG carrier under the combined actions of wave, current and wind can be quite complex. This paper presents a comprehensive study on the hydrodynamics of an FLNG system with a focus on the nonlinear coupling effects of vessels and connection systems based on the concept FLNG prototype recently designed for South China Sea. In this study, the hydrodynamic characteristics of the two floating vessels connected through hawsers and fenders are investigated using a state-of-the-art time-domain simulation code SIMO, considering their mechanical and hydrodynamic coupling effects. The simulation model consisting of FLNG and LNG carrier is developed and calibrated by a series of model tests including a tuned damping and viscous levels. The hydrodynamic performances of the two floating vessels under an extreme sea state during side-by-side offloading operation are obtained, and their relative motions and the force responses of the connection hawsers and fenders are analyzed. Sensitivity studies are conducted to clarify contributions from the pretension and the stiffness of the connection hawsers. The effects on the hydrodynamic performance of the vessels and on the loads of the connection system are also investigated.

  18. A side-by-side comparison of CPV module and system performance

    SciTech Connect

    Muller, Matthew; Marion, Bill; Kurtz, Sarah; Ghosal, Kanchan; Burroughs, Scott; Libby, Cara; Enbar, Nadav

    2016-02-23

    A side-by-side comparison is made between concentrator photovoltaic module and system direct current aperture efficiency data with a focus on quantifying system performance losses. The individual losses measured/calculated, when combined, are in good agreement with the total loss seen between the module and the system. Results indicate that for the given test period, the largest individual loss of 3.7% relative is due to the baseline performance difference between the individual module and the average for the 200 modules in the system. A basic empirical model is derived based on module spectral performance data and the tabulated losses between the module and the system. The model predicts instantaneous system direct current aperture efficiency with a root mean square error of 2.3% relative.

  19. Tracked-Vehicle Gradeability and Side-Slope Performance

    DTIC Science & Technology

    1987-05-01

    con- travene the provisions of this ITOP. Any changes to this ITOP require the ap- proval of all ratifying nations. If a ratifying nation must...traction, up to 60% b . Side slopes, allowing sufficient traction, up to 40% c. Skip rings or wireless data-coupling devices as required...a. Vehicle speed + 0.2km/hr (para 4.1.2, grade speed test) + 2.0km/hr (para 4.2, side-slope performance) b . Engine and drive-shaft speeds

  20. Air Quality Side Event Proposal November 2016 GEO XIII Plenary in St. Petersburg, Russia

    EPA Science Inventory

    The Group on Earth Observations (GEO), which EPA has participated in since 2003, has put out a call for Side Events for its thirteenth annual international Plenary Meeting which is in St. Petersburg, Russia this year during November, 2016. EPA has put on Side Events on Air Quali...

  1. Air Conditioning. Performance Objectives. Intermediate Course.

    ERIC Educational Resources Information Center

    Long, William

    Several intermediate performance objectives and corresponding criterion measures are listed for each of seven terminal objectives for an intermediate air conditioning course. The titles of the seven terminal objectives are Refrigeration Cycle, Job Requirement Skills, Air Conditioning, Trouble Shooting, Performance Test, Shop Management, and S.I.E.…

  2. Air Combat Maneuvering Performance Measurement

    DTIC Science & Technology

    1979-09-01

    several major purposes. First, it would provide improved feedback to Air Combat Maneuvering (ACM) students concerning their progress through the flight...materials and syllabi. Consistent patterns of weakness in the students would serve as an indicator of a need for adjustment and improvement in the program...adversary maneuvers. BFM students learn to perceive the aspect angle, angle-off, and closure rate of the opposing aircraft. They learn the proper maneuver

  3. Sampling medium side resistance to uptake of semivolatile organic compounds in passive air samplers.

    PubMed

    Zhang, Xianming; Tsurukawa, Masahiro; Nakano, Takeshi; Lei, Ying D; Wania, Frank

    2011-12-15

    Current theory of the uptake of semivolatile organic compounds in passive air samplers (PAS) assumes uniform chemical distribution and no kinetic resistance within the passive sampling media (PSM) such as polystyrene-divinylbenzene resin (XAD) and polyurethane foam (PUF). However, these assumptions have not been tested experimentally and are challenged by some recently reported observations. To test the assumptions, we performed kinetic uptake experiments indoors using cylindrical PSM that had been concentrically segmented into three layers. Both XAD and PUF were positioned in the same type of sampler housing to eliminate the variation caused by the different housing designs, which enabled us to quantify differences in uptake caused by the properties of the PSM. Duplicated XAD (PUF) samples were retrieved after being deployed for 0, 1 (0.5), 2 (1), 4 (2), 8 (4), 12 (8), and 24 (12) weeks. Upon retrieval, the PSM layers were separated and analyzed individually for PCBs. Passive sampling rates (R) were lower for heavier PCB homologues. Within a homologue group, R for XAD was higher than that for PUF, from which we infer that the design of the "cylindrical can" housing typically used for XAD PAS lowers the R compared to the "double bowl" shelter commonly used for PUF-disk PAS. Outer layers of the PSM sequestered much higher levels of PCBs than inner layers, indicative of a kinetic resistance to chemical transfer within the PSM. The effective diffusivities for chemical transfer within PSM were derived and were found negatively correlated with the partition coefficients between the PSM and air. Based on the results, we conclude that the PSM-side kinetic resistance should be considered when investigating factors influencing R and when deriving R based on the loss of depuration compounds.

  4. Performance Characteristics of Thick Silicon Double-sided Strip Detectors.

    PubMed

    Shokouhi, Sepideh; McDonald, Benjamin S; Durko, Heather L; Fritz, Mark A; Furenlid, Lars R; Peterson, Todd E

    2007-01-01

    This work presents characterization studies of thick silicon double-sided strip detectors for a high-resolution small-animal SPECT. The dimension of these detectors is 60 mm × 60 mm × 1 mm. There are 1024 strips on each side that give the coordinates of the photon interaction, with each strip processed by a separate ASIC channel. Our measurement shows that intrinsic spatial resolution equivalent to the 59 µm strip pitch is attainable. Good flood uniformity can be achieved by proper setting of a 4-bit DAC in each ASIC channel to remove trigger threshold variations. This is particularly important for triggering at low energies. The thick silicon DSSD shows high potential for small-animal SPECT imaging.

  5. Performance Characteristics of Thick Silicon Double-sided Strip Detectors

    PubMed Central

    Shokouhi, Sepideh; McDonald, Benjamin S.; Durko, Heather L.; Fritz, Mark A.; Furenlid, Lars R.; Peterson, Todd E.

    2015-01-01

    This work presents characterization studies of thick silicon double-sided strip detectors for a high-resolution small-animal SPECT. The dimension of these detectors is 60 mm × 60 mm × 1 mm. There are 1024 strips on each side that give the coordinates of the photon interaction, with each strip processed by a separate ASIC channel. Our measurement shows that intrinsic spatial resolution equivalent to the 59 µm strip pitch is attainable. Good flood uniformity can be achieved by proper setting of a 4-bit DAC in each ASIC channel to remove trigger threshold variations. This is particularly important for triggering at low energies. The thick silicon DSSD shows high potential for small-animal SPECT imaging. PMID:26778911

  6. Measured Performance of Occupied, Side-by-Side, South Texas Homes

    SciTech Connect

    Chasar, Dave; vonSchramm, Valerie

    2012-09-01

    The performance of three homes in San Antonio, Texas with identical floor plans and orientation were evaluated through a partnership between the Florida Solar Energy Center (FSEC), CPS Energy, and Woodside Homes of South Texas. Measurements included whole house gas and electric use as well as heating, cooling, hot water, major appliances and indoor and outdoor conditions. One home built to builder standard practice served as the control, while the other homes demonstrated high performance features. Utility peak electric load comparisons of these dual-fuel homes provide an assessment of envelope and equipment improvements.

  7. Performance of a matrix air heater

    NASA Astrophysics Data System (ADS)

    Sodha, M. S.; Bansal, N. K.; Singh, D.; Bharadwaj, S. S.

    1982-10-01

    This communication presents a study of a porous flat plate solar air heater. An earlier theory used to analyze such a system has been modified by using: (1) appropriate boundary conditions and also (2) by considering the realistic case of different air and matrix temperatures. Numerical calculations have been performed to bring out the difference between the earlier theory and the present theory. The results of the present theory are found to be in excellent agreement with the measurements of an experiment. The yearly performance of the system has also been evaluated for Delhi-type climates.

  8. Measured Performance of Occupied, Side-by-Side, South Texas Homes

    SciTech Connect

    Chasar, D.; vonSchramm, V.

    2012-09-01

    The performance of three homes in San Antonio, Texas with identical floor plans and orientation were evaluated through a partnership between the Florida Solar Energy Center (FSEC), CPS Energy, and Woodside Homes of South Texas. Measurements included whole house gas and electric use as well as heating, cooling, hot water, major appliances and indoor and outdoor conditions. One home built to builder standard practice served as the control, while the other homes demonstrated high performance features. Utility peak electric load comparisons of these dual-fuel homes provide an assessment of envelope and equipment improvements. The control home used natural gas for space and water heating only, while the improved homes had gas heating and major appliances with the exception of a high efficiency heat pump in one home. Data collection began in July of 2009 and continued through April of 2011. Energy ratings for the homes yielded E-Scales (aka HERS indices) of 86 for the control home, 54 for one improved home and 37 for the other home which has a 2.4kW photovoltaic array.

  9. Dental air turbine handpiece performance testing.

    PubMed

    Dyson, J E; Darvell, B W

    1995-10-01

    Air turbine handpieces are expected to continue to be widely used as the main means of carrying out dental cutting work and scope exists for further design improvements. An understanding of the theoretical principles governing the performance of these devices seems essential for the systematic development of better handpiece designs and methods of specification. Furthermore, for experimental work on cutting behaviour with air turbine equipment, this knowledge is required for appropriate characterization of the performance of the particular handpiece used with respect to actual rates of energy disposition. The literature relating to air turbine handpiece performance is critically reviewed to assess currently available methods of measuring important variables such as speed, torque, and power. In this, consideration is given to the current state of knowledge of the influence on these variables of air pressure, flow and turbine design features. It is apparent that, although various measurement methods have been described and data for individual handpieces published, no attempt has yet been made to explore the functional relationships that exist between the variables. It is concluded that there is a need to identify the factors influencing turbine performance, to develop measurement systems which would provide adequate accuracy and precision and then to investigate the functional relationships between these relevant variables.

  10. The exposure of children to deploying side air bags: an initial field assessment.

    PubMed

    Arbogast, Kristy B; Kallan, Michael J

    2007-01-01

    Tremendous effort has been invested in the laboratory to ensure side air bag (SAB) deployments minimize injury metrics in pediatric anthropometric test devices (ATDs). Little is known, however, about the experience of children exposed to this technology in real world crashes. Therefore, the objective of this study was to determine the prevalence of SAB exposure in children and provide estimates of injury risk among those exposed. This study utilized data from the Partners for Child Passenger Safety study, a large-scale child-focused crash surveillance system, to identify a probability sample of 348 child occupants, age 0-15 years, weighted to represent 6,600 children, in vehicles of model year 1998 and newer, equipped with SABs, in side impact crashes from three large U.S. regions between 1/1/05 and 12/31/06. In the study sample, 27 children per 1000 children in crashes were exposed to a deployed side air bag. Over 75% of these children were seated in the rear seat and 83% were exposed to a head curtain SAB. 65% of those exposed were less than 9 years of age. Of those exposed, 10.6% sustained an AIS2+ injury; all injuries were of the AIS 2 level and limited to the head or upper extremity. This paper provides the first population-based estimates of the exposure of children to SABs. Initial experience suggests that the risk of injury is fairly low with only one in ten sustaining injury - none of which were serious or life threatening. These findings offer assurance that efforts by regulators and the automotive industry to minimize negative consequences from SABs to vulnerable occupants appear to be effective and cause no change in the current recommendation of safe seating for children next to SABs.

  11. Impact of air pollutants on athletic performance

    SciTech Connect

    Pierson, W.E. )

    1989-05-01

    Human controlled and observational studies both lead to the conclusion of air pollution adversely affecting athletic performance during training and competition. The dosage of various air pollutants during exercise is much higher due to the marked increase in ventilatory rate and concomitant nasal and oral breathing. This is particularly true for sulfur dioxide which is a highly water-soluble gas and is normally absorbed in the upper airway during nasal breathing. With heavy exercise, oral pharyngeal breathing is the predominant mode of breathing and much larger amounts of sulfur dioxide are delivered to the lower airway resulting in significant impact upon the lower respiratory tract. More recently, several controlled human studies have shown that a combination of exercise and air pollutants such as ozone (O3) or sulfur dioxides (SO2) cause a significant increase in bronchoconstriction and air flow obstruction when compared to the same exposure at rest. In strenuous athletic competition such as the Olympic Games where small increments of time often determine the ultimate success of athletes, the impact of air pollutants and subsequent adverse ventilatory changes can affect athletic performance. 62 references.

  12. A Walk on the Human Performance Side--Part 1

    ERIC Educational Resources Information Center

    Addison, Roger M.; Haig, Carol

    2012-01-01

    Using their "license to snoop," performance architects uncover the nuances of how work gets done in an organization. This is the first of a four-part series in which each article will present a different organizational level. Typical performance issues and opportunities for each level will be discussed, and helpful models and tools will be shared.…

  13. Effects of Small-Sided Games on Physical Conditioning and Performance in Young Soccer Players

    PubMed Central

    Katis, Athanasios; Kellis, Eleftherios

    2009-01-01

    The purpose of this study was to examine, first, the movement actions performed during two different small-sided games and, second, their effects on a series of field endurance and technical tests. Thirty-four young soccer players (age: 13 ± 0.9 yrs; body mass: 62.3 ± 15.1 kg; height: 1.65 ± 0.06 m) participated in the study. Small-sided games included three-a-side (3 versus 3 players) and six-a-side (6 versus 6 players) games consisting of 10 bouts of 4 min duration with 3 min active recovery between bouts. Soccer player performance was evaluated using five field tests: a) 30m sprint, b) throw-in for distance, c) Illinois Agility Test, d) dribbling the ball and e) horizontal jump before, in the middle and after the implementation of both game situations. Heart rate was monitored during the entire testing session. Each game was also filmed to measure soccer movements within the game. The ANOVA analysis indicated that the three-a- side games displayed significantly higher heart rate values compared with the six-a-side games (p < 0.05). The number of short passes, kicks, tackles, dribbles and scoring goals were significantly higher during the three-a-side compared with the six-a-side game condition (p < 0. 05) while players performed more long passes and headed the ball more often during the six-a-side (p < 0.05). After the three-a-side games, there was a significant decline in sprint and agility performance (p < 0.05), while after both game conditions significant alterations in the throw-in and the horizontal jump performance were observed (p < 0.05). The results of the present study indicated that three-a-side games provide higher stimulus for physical conditioning and technical improvement than six-a-side games and their use for training young soccer players is recommended. Key points Three-a-side games display higher HR compared with six-a-side games. In the three-a-side games players performed more short passes, kicks, dribbles, tackles and scored more goals

  14. A Novel Approach to Model the Air-Side Heat Transfer in Microchannel Condensers

    NASA Astrophysics Data System (ADS)

    Martínez-Ballester, S.; Corberán, José-M.; Gonzálvez-Maciá, J.

    2012-11-01

    The work presents a model (Fin1D×3) for microchannel condensers and gas coolers. The paper focusses on the description of the novel approach employed to model the air-side heat transfer. The model applies a segment-by-segment discretization to the heat exchanger adding, in each segment, a specific bi-dimensional grid to the air flow and fin wall. Given this discretization, the fin theory is applied by using a continuous piecewise function for the fin wall temperature. It allows taking into account implicitly the heat conduction between tubes along the fin, and the unmixed air influence on the heat capacity. The model has been validated against experimental data resulting in predicted capacity errors within ± 5%. Differences on prediction results and computational cost were studied and compared with the previous authors' model (Fin2D) and with other simplified model. Simulation time of the proposed model was reduced one order of magnitude respect the Fin2D's time retaining its same accuracy.

  15. Performance outcomes and unwanted side effects associated with energy drinks.

    PubMed

    Mora-Rodriguez, Ricardo; Pallarés, Jesús G

    2014-10-01

    Energy drinks are increasingly popular among athletes and others. Advertising for these products typically features images conjuring great muscle power and endurance; however, the scientific literature provides sparse evidence for an ergogenic role of energy drinks. Although the composition of energy drinks varies, most contain caffeine; carbohydrates, amino acids, herbs, and vitamins are other typical ingredients. This report analyzes the effects of energy drink ingredients on prolonged submaximal (endurance) exercise as well as on short-term strength and power (neuromuscular performance). It also analyzes the effects of energy drink ingredients on the fluid and electrolyte deficit during prolonged exercise. In several studies, energy drinks have been found to improve endurance performance, although the effects could be attributable to the caffeine and/or carbohydrate content. In contrast, fewer studies find an ergogenic effect of energy drinks on muscle strength and power. The existing data suggest that the caffeine dose given in studies of energy drinks is insufficient to enhance neuromuscular performance. Finally, it is unclear if energy drinks are the optimal vehicle to deliver caffeine when high doses are needed to improve neuromuscular performance.

  16. Evaluation of antimotion sickness drug side effects on performance

    NASA Technical Reports Server (NTRS)

    Wood, C. D.; Manno, J. E.; Manno, B. R.; Redetzki, H. M.; Wood, M. J.

    1985-01-01

    The effects of antimotion-sickness drugs on the performance in computerized-pursuit-meter tests of groups of ten 18-30-yr-old male and female subjects are investigated experimentally using double-blind placebo techniques. The results are presented in tables and graphs and discussed in detail. The proficiency scores are as good as or better than placebo values for subjects given d-amphetamine (DA) 5 or 10 mg, promethazine (P) 25 mg + scopolamine (S) 400 ng + DA 10 mg, S 1 mg + DA 10 mg, S 250-600 ng, marezine 50 mg, meclizine 50 mg, dimenhydrinate 50 mg, S 1 mg + DA 5 mg, or P 25 mg + DA 10 mg. Significantly lower scores are seen in subjects given S 800 ng or 1 mg, P 25 mg (oral or IM), P 25 mg + S 400 ng, and P 25 mg oral + P 25 mg IM + DA 10 mg.

  17. High performance zinc air fuel cell stack

    NASA Astrophysics Data System (ADS)

    Pei, Pucheng; Ma, Ze; Wang, Keliang; Wang, Xizhong; Song, Mancun; Xu, Huachi

    2014-03-01

    A zinc air fuel cell (ZAFC) stack with inexpensive manganese dioxide (MnO2) as the catalyst is designed, in which the circulation flowing potassium hydroxide (KOH) electrolyte carries the reaction product away and acts as a coolant. Experiments are carried out to investigate the characteristics of polarization, constant current discharge and dynamic response, as well as the factors affecting the performance and uniformity of individual cells in the stack. The results reveal that the peak power density can be as high as 435 mW cm-2 according to the area of the air cathode sheet, and the influence factors on cell performance and uniformity are cell locations, filled state of zinc pellets, contact resistance, flow rates of electrolyte and air. It is also shown that the time needed for voltages to reach steady state and that for current step-up or current step-down are both in milliseconds, indicating the ZAFC can be excellently applied to vehicles with rapid dynamic response demands.

  18. Performance Evaluation of Photovoltaic Solar Air Conditioning

    NASA Astrophysics Data System (ADS)

    Snegirjovs, A.; Shipkovs, P.; Lebedeva, K.; Kashkarova, G.; Migla, L.; Gantenbein, P.; Omlin, L.

    2016-12-01

    Information on the electrical-driven solar air conditioning (SAC) is rather scanty. A considerable body of technical data mostly concerns large-scale photo-voltaic solar air conditioning (PV-SAC) systems. Reliable information about the energy output has arisen only in recent years; however, it is still not easily accessible, and sometimes its sources are closed. Despite these facts, solar energy researchers, observers and designers devote special attention to this type of SAC systems. In this study, performance evaluation is performed for the PV-SAC technology, in which low-power (up to 15 kWp of cooling power on average) systems are used. Such a system contains a PV electric-driven compression chiller with cold and heat sensible thermal storage capacities, and a rejected energy unit used for preheating domestic hot water (DHW). In a non-cooling season, it is possible to partly employ the system in the reverse mode for DHW production. In this mode, the ambient air serves as a heat source. Besides, free cooling is integrated in the PV-SAC concept.

  19. Air quality and human performance. Chapter 16

    SciTech Connect

    Pandolf, K.B.

    1987-09-01

    The various air pollutants have been classified as primary or secondary pollutants. Primary pollutants are emitted directly to the environment from their source and include carbon monoxide, sulfur oxides, nitrogen oxides, and primary particulates. Secondary pollutants develop from interactions of primary pollutants and include ozone, peroxyacetyl nitrate, and certain aerosols. Carbon monoxide does not appear to cause decrements in submaximal exercise performance in healthy individuals; however, cardiovascularly-impaired individuals appear to be at significant risk during submaximal exercise even at low carboxyhemoglobin levels. Maximal exercise performance for healthy individuals seems to be altered by breathing carbon monoxide with the critical concentration being 4.3% carboxyhemoglobin. The threshold level of sulfur dioxide which effects submaximal exercise performance in healthy individuals is between 1.0 and 3.0 ppm while asthmatic individuals and possibly others with pulmonary hyperactivity are affected at a lower threshold concentration between 0.20 and 0.50 ppm. Several studies suggest that healthy and asthmatic individuals may adapt to sulfur but, unfortunately, no research has investigated adaptation to this pollutant during physical exercise. While no studies have been reported which evaluate maximal exercise performance, nitrogen dioxide exposure does not appear to adversely affect submaximal exercise performance in healthy individuals. The physiological performance effects of breathing primary particulates have not been directly evaluated during exercise in man. Ozone exposure does not appear to limit submaximal exercise performance at light to moderate exercise intensities.

  20. Performance of a CO2 impedimetric sensor prototype for air quality monitoring.

    PubMed

    Mandayo, Gemma García; Herrán, Jaime; Castro-Hurtado, Irene; Castaño, Enrique

    2011-01-01

    Carbon dioxide detection is a relevant issue in many fields, and this work focuses on the use of a BaTiO(3)-CuO sputtered thin film layer in a gas sensor prototype for air quality measurements. For this, a double side sensor was fabricated, with a Pt heater on one side and the sensing layer over the electrodes on the other side. The uniformity of the temperature on the sensing layer was tested and further tests to check its sensing performance were carried out. Humidity influence in the detection was found to be almost negligible within the usual range in air quality measurements and repeatability tests show satisfactory results for air quality control purposes.

  1. Dynamic Performance of a Residential Air-to-Air Heat Pump.

    ERIC Educational Resources Information Center

    Kelly, George E.; Bean, John

    This publication is a study of the dynamic performance of a 5-ton air-to-air heat pump in a residence in Washington, D.C. The effect of part-load operation on the heat pump's cooling and heating coefficients of performance was determined. Discrepancies between measured performance and manufacturer-supplied performance data were found when the unit…

  2. Significant Differences in Pediatric Psychotropic Side Effects: Implications for School Performance

    ERIC Educational Resources Information Center

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

    2012-01-01

    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…

  3. Multidimensional scaling analysis of simulated air combat maneuvering performance data.

    PubMed

    Polzella, D J; Reid, G B

    1989-02-01

    This paper describes the decomposition of air combat maneuvering by means of multidimensional scaling (MDS). MDS analyses were applied to performance data obtained from expert and novice pilots during simulated air-to-air combat. The results of these analyses revealed that the performance of expert pilots is characterized by advantageous maneuverability and intelligent energy management. It is argued that MDS, unlike simpler metrics, permits the investigator to achieve greater insights into the underlying structure associated with performance of a complex task.

  4. Performance Analysis of a Link-16/JTIDS Compatible Waveform With Noncoherent Detection, Diversity and Side Information

    DTIC Science & Technology

    2009-09-01

    OF A LINK-16/ JTIDS COMPATIBLE WAVEFORM WITH NONCOHERENT DETECTION, DIVERSITY AND SIDE INFORMATION by Ioannis Kagioglidis September 2009...3. REPORT TYPE AND DATES COVERED Master’s Thesis 4. TITLE AND SUBTITLE: Performance Analysis of a Link-16/ JTIDS Compatible Waveform with...System ( JTIDS ) is a hybrid frequency-hopped, direct sequence spread spectrum system. A (31, 15) Reed-Solomon (RS) code is used for forward error

  5. Boosting the ambipolar performance of solution-processable polymer semiconductors via hybrid side-chain engineering.

    PubMed

    Lee, Junghoon; Han, A-Reum; Yu, Hojeong; Shin, Tae Joo; Yang, Changduk; Oh, Joon Hak

    2013-06-26

    Ambipolar polymer semiconductors are highly suited for use in flexible, printable, and large-area electronics as they exhibit both n-type (electron-transporting) and p-type (hole-transporting) operations within a single layer. This allows for cost-effective fabrication of complementary circuits with high noise immunity and operational stability. Currently, the performance of ambipolar polymer semiconductors lags behind that of their unipolar counterparts. Here, we report on the side-chain engineering of conjugated, alternating electron donor-acceptor (D-A) polymers using diketopyrrolopyrrole-selenophene copolymers with hybrid siloxane-solubilizing groups (PTDPPSe-Si) to enhance ambipolar performance. The alkyl spacer length of the hybrid side chains was systematically tuned to boost ambipolar performance. The optimized three-dimensional (3-D) charge transport of PTDPPSe-Si with pentyl spacers yielded unprecedentedly high hole and electron mobilities of 8.84 and 4.34 cm(2) V(-1) s(-1), respectively. These results provide guidelines for the molecular design of semiconducting polymers with hybrid side chains.

  6. PERFORMANCE TESTING OF AIR CLEANING PRODUCTS

    EPA Science Inventory

    The paper discuses the application of the Environmental Technology Verification (ETV) Program for products that clean ventilation air to the problem of protecting buildings from chemical and biological attack. This program is funded by the U.S. Environmental Protection Agency und...

  7. Unsteady Performance of Finite-Span Pitching Propulsors in Mixtures of Side-by-Side and In-Line Arrangements

    NASA Astrophysics Data System (ADS)

    Kurt, Melike; Moored, Keith

    2016-11-01

    Birds, insects, and fish propel themselves by flapping their wings or oscillating their fins in unsteady motions. Many of these animals fly or swim in groups or collectives, typically described as flocks, swarms and schools. The three-dimensional steady flow interactions and the two dimensional unsteady flow interactions that occur in collectives are well characterized. However, the interactions that occur among three-dimensional unsteady propulsors remain relatively unexplored. The aim of the current study is to measure the forces acting on and the energetics of two finite-span pitching wings. The wings are arranged in mixtures of canonical in-line and side-by-side configurations while the phase delay between the pitching wings is varied. The thrust force, fluid-mediated interaction force between the wings and the propulsive efficiency are quantified. The three-dimensional interaction mechanisms are compared and contrasted with previously examined two-dimensional mechanisms. Stereoscopic particle image velocimetry is employed to characterize the three-dimensional flow structures along the span of the pitching wings.

  8. The Bright Side of Threatened Narcissism: Improved Performance Following Ego Threat.

    PubMed

    Nevicka, Barbora; Baas, Matthijs; Ten Velden, Femke S

    2016-12-01

    Narcissistic individuals have highly positive self-views and overestimate their abilities. Consequently, they tend to react aggressively whenever they receive information that does not match their high self-views (ego threat). We argue that focusing on aggression merely portrays a one-sided view of narcissistic individuals and the manner in which they counter ego threats. We propose that following ego threat, narcissism can also fuel performance. In four studies, we measured nonclinical narcissism and allocated Dutch undergraduate university students (N1  = 175, N2  = 142, N3  = 159, N4  = 174) to either an ego threat or a no ego threat condition. Ego threat involved negative feedback (Studies 1-2) or threat to uniqueness (Studies 3-4). We measured participants' intentions to complete a challenging task (Study 1), their creative performance (Studies 2-3), and their performance on an anagram task (Study 4). Across Studies 1-3, we consistently found that following ego threat, higher nonclinical narcissism was associated with greater willingness to perform tasks that enabled demonstration of abilities and enhanced creative performance. These results were confirmed using a meta-analysis. However, anagram performance was not enhanced following ego threat. We provide additional analyses that might help explain this. Our findings thus reveal a more positive side to the way narcissistic individuals manage threats to their self-image.

  9. Air sampler performance at Ford's farm range

    SciTech Connect

    Glissmeyer, J.A.; Johnston, J.W.

    1984-07-01

    An air-sampling system for a large-caliber depleted uranium (DU) penetrator firing range was tested. The objectives of the test were: to determine the bias between the monitoring readings and DU concentrations; and to determine if the target bay real-time monitor (RTM) tracks the decaying dust concentration. The test procedure was to operate total and respirable airborne particle samplers adjacent to the target bay monitors. A series of air samples was also taken after the test firings adjacent to the target bay RTM. Exhaust particle samples were analyzed for gross alpha, gross beta and uranium content. The target bay RTM correlated well (0.977) with the sequential samples. Average concentration from the RTM did not correlate with either the long-term total or respirable sampler DU concentrations. The monitor used to confirm a low dust concentration when the door is open correlated well (0.810) with the RTM; the other bay monitor did not. In the ventilation discharge, the long-term average monitor readings did not correlate with DU concentrations, probably due to levels near lower detection limits. Smearable surface-contamination samples showed highest contamination on the equipment, gravel floor and exhaust intake. The location air-intake contamination increased over the first 3 rounds. Contamination was reduced by a low-pressure water spray washdown to about the same concentration as often the second round, then remained at about twice the level. 2 references, 18 figures, 16 tables. (MF)

  10. Impact of jammer side information on the performance of anti-jam systems

    NASA Astrophysics Data System (ADS)

    Lim, Samuel

    1992-03-01

    The Chernoff bound parameter, D, provides a performance measure for all coded communication systems. D can be used to determine upper-bounds on bit error probabilities (BEPs) of Viterbi decoded convolutional codes. The impact on BEP bounds of channel measurements that provide additional side information can also be evaluated with D. This memo documents the results of a Chernoff bound parameter evaluation in optimum partial-band noise jamming (OPBNJ) for both BPSK and DPSK modulation schemes. Hard and soft quantized receivers, with and without jammer side information (JSI), were examined. The results of this analysis indicate that JSI does improve decoding performance. However, a knowledge of jammer presence alone achieves a performance level comparable to soft decision decoding with perfect JSI. Furthermore, performance degradation due to the lack of JSI can be compensated for by increasing the number of levels of quantization. Therefore, an anti-jam system without JSI can be made to perform almost as well as a system with JSI.

  11. Thermal performance of a new solar air heater

    SciTech Connect

    Tiris, C.; Ozbalta, N.; Tiris, M.; Dincer, I.

    1995-05-01

    A solar air heater, part of a food drying system using solar energy as a renewable energy source for heat, was developed and tested for several agricultural products (i.e., sultana grapes, green beans, sweet peppers, chili peppers). Drying processes were conducted in the chamber with forced natural air heated partly by solar energy. Solar air heater performances were discussed along with estimates of energy efficiency of the system. The obtained results indicate that the present system is efficiency and effective.

  12. A correlation to predict the heat flux on the air-side of a vapor chamber with overturn-U flattened tubes

    NASA Astrophysics Data System (ADS)

    Srimuang, Wasan; Limkaisang, Viroj

    2016-08-01

    The heat transfer characteristics of a conventional vapor chamber (CVC) and a loop vapor chamber (LVC) are compared. The vapor chambers consisted of a stainless steel box with different covers. The results indicated that the heat flux and convective heat transfer coefficient of the air-side of LVC is higher than CVC. An empirical correlation was developed to predict the convective heat transfer coefficient of the air-side of the LVC.

  13. Performance evaluation of child safety seats in far-side lateral sled tests at varying speeds.

    PubMed

    Ghati, Yoganand; Menon, Rajiv A; Milone, Mary; Lankarani, Hamid; Oliveres, Gerardo

    2009-10-01

    Protection of children in Child Safety Seats (CSS) in side impact crashes has been a topic of recent studies. The objective of this study was to evaluate the performance of CSS in far-side impacts through a series of sled tests conducted at varying test speeds. Forty eight sled tests were conducted at three speeds (24 km/h, 29 km/h and 36 km/h), under two different CSS attachment conditions (LATCH and seat belt attached), using rear facing and forward facing CSS from four different manufacturers. Analyses were conducted to examine head retention within the CSS, velocity of the head as it passes an imaginary plane (cross over into other occupant space or door), lateral trajectory of the head and knee; head, chest and pelvis accelerations; neck and lumbar loads and moments. In addition to these parameters, the CSS were visually inspected for structural integrity after each test. Results from these sled tests highlighted the differential performance of CSS in far-side impacts. During the tests, all CSS experienced significant lateral movement irrespective of attachment type. In rear facing CSS tests, one of the designs failed as the seat disengaged from its base. In forward facing CSS tests, it was observed that the seat belt attached CSS experienced less rotational motion than the LATCH attached CSS. ATD head retention within the seat was not achieved with either CSS attachments at any speed. The findings from this study augment the current efforts to define regulatory sled setup procedure for far-side impact crashes involving children in CSS, which currently does not exist and will eventually further the protection of children in automobiles.

  14. Indoor Air Quality in High Performance Schools

    EPA Pesticide Factsheets

    High performance schools are facilities that improve the learning environment while saving energy, resources, and money. The key is understanding the lifetime value of high performance schools and effectively managing priorities, time, and budget.

  15. Thermotechnical performance of an air-cooled tuyere with air cooling channels in series

    NASA Astrophysics Data System (ADS)

    Shen, Yuansheng; Zhou, Yuanyuan; Zhu, Tao; Duan, Guangbin

    2017-01-01

    To reduce the cooling air consumption for an air-cooled tuyere, an air-cooled tuyere with air cooling channels in series is developed based on several hypotheses, i.e., a transparent medium in the blast furnace, among others, and the related mathematical models are introduced and developed. Referring to the data from a BF site, the thermotechnical computation for the air-cooled tuyere was performed, and the results show that when the temperature of the inlet cooling air increases, the temperatures for the outlet cooling air, the outer surface of the tuyere, the walls of the air cooling channels and the center channel as well as the heat going into the center channel increase, but the heat absorbed by the cooling air flowing through the air cooling channels decreases. When the cooling air flow rate under the standard state increases, the physical parameters mentioned above change in an opposite directions. Compared to a water-cooled tuyere, the energy savings for an air-cooled tuyere are more than 0.23 kg/min standard coal.

  16. The influence of air travel on athletic performance.

    PubMed

    Youngstedt, S D; O'Connor, P J

    1999-09-01

    Rapid transmeridian flight is a common reality for modern athletes and it has often been assumed that air travel has detrimental effects on athletic performance. The plausibility of this assumption is supported by established deteriorations in sleep and mood following transmeridian flight. However, the scientific evidence supporting the assumption is neither consistent nor compelling. Studies that have assessed athletic performance following transmeridian flight have produced mixed results and are characterised by major methodological flaws. Recent retrospective assessments of athletic team performance based on distance travelled have generally failed to indicate performance impairments following transmeridian flight. The plausibility of transmeridian air travel impairing athletic performance would be indicated by demonstration of an internally-driven circadian rhythm of athletic performance, or of deleterious performance consequences following sleep deprivation or desynchronisation between the circadian system and the environment. More rigorous research is needed to establish whether athletic performance is influenced by air travel.

  17. Air-side flow and heat transfer in compact heat exchangers: A discussion of enhancement mechanisms

    SciTech Connect

    Jacobi, A.M.; Shah, R.K.

    1998-10-01

    The behavior of air flows in complex heat exchanger passages is reviewed with a focus on the heat transfer effects of boundary-layer development, turbulence, spanwise and streamwise vortices, and wake management. Each of these flow features is discussed for the plain, wavy, and interrupted passages found in contemporary compact heat exchanger designs. Results from the literature are used to help explain the role of these mechanisms in heat transfer enhancement strategies.

  18. The Human Side of Cyber Conflict: Organizing, Training, and Equipping the Air Force Cyber Workforce

    DTIC Science & Technology

    2016-06-01

    toward cyber operations but also a grasp of legal , policy, and ethical issues related to cyber operations and national se- curity. However, this cadre is...competitions provide legal outlets for students with creative computer skills. From these competitions and through its sponsorship of and advertising at these...flexibility to reliably move Airmen as needed, we recommend that the Air Force explore the legalities of including noncompete clauses to restrict

  19. An inexact double-sided chance-constrained model for air quality management in Nanshan District, Shengzhen, China

    NASA Astrophysics Data System (ADS)

    Shao, Liguo; Xu, Ye; Huang, Guohe

    2014-12-01

    In this study, an inexact double-sided fuzzy-random-chance-constrained programming (IDSFRCCP) model was developed for supporting air quality management of the Nanshan District of Shenzhen, China, under uncertainty. IDSFRCCP is an integrated model incorporating interval linear programming and double-sided fuzzy-random-chance-constrained programming models. It can express uncertain information as both fuzzy random variables and discrete intervals. The proposed model was solved based on the stochastic and fuzzy chance-constrained programming techniques and an interactive two-step algorithm. The air quality management system of Nanshan District, including one pollutant, six emission sources, six treatment technologies and four receptor sites, was used to demonstrate the applicability of the proposed method. The results indicated that the IDSFRCCP was capable of helping decision makers to analyse trade-offs between system cost and risk of constraint violation. The mid-range solutions tending to lower bounds with moderate αh and qi values were recommended as decision alternatives owing to their robust characteristics.

  20. HVAC system performance and indoor air quality

    SciTech Connect

    Newman, J.L. )

    1991-01-01

    This paper reports that in the mid-seventies, the American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE) promulgated ASHRAE Standard 90-75 Energy Conservation in New Building Design, which called for revised minimum ventilation rates and the elimination of energy-wasting HVAC systems. Most building codes which cover energy conservation in the late seventies and eighties referred to this standard. This lowering of ventilation rates, coupled with the tighter building envelope (walls, windows, doors and roof) led to a reduction in outside air, both by engineering design and by minimizing infiltration through the structure. The minimum ventilation rates are based on the assumption that average concentrations of tobacco smoke exist in all enclosed spaces (30 percent of the population being smokers at two cigarettes per hour), rather than having separate rates for smoking and nonsmoking areas, as in the 1981 revision of the Standard. If tobacco smoke is ever declared a carcinogen, it will undoubtedly prompt a review of Standard 62-1989, as well as hasten totally smoke-free buildings.

  1. Novel Fluorinated Polymers Containing Short Perfluorobutyl Side Chains and Their Super Wetting Performance on Diverse Substrates.

    PubMed

    Jiang, Jingxian; Zhang, Guangfa; Wang, Qiongyan; Zhang, Qinghua; Zhan, Xiaoli; Chen, Fengqiu

    2016-04-27

    Because the emission of perfluorooctanoic acid (PFOA) was completely prohibited in 2015, the widely used poly- and perfluoroalkyl substances with long perfluoroalkyl groups must be substituted by environmentally friendly alternatives. In this study, one kind of potential alternative (i.e., fluorinated polymers with short perfluorobutyl side chains) has been synthesized from the prepared monomers {i.e., (perfluorobutyl)ethyl acrylate (C4A), (perfluorobutyl)ethyl methacrylate (C4MA), 2-[[[[2-(perfluorobutyl)]sulfonyl]methyl]amino]ethyl acrylate (C4SA), and methacrylate (C4SMA)}, and the microstructure, super wetting performance, and applications of the synthesized fluorinated polymers were systematically investigated. The thermal and crystallization behaviors of the fluoropolymer films were characterized by differential scanning calorimetry and wide-angle X-ray diffraction analysis, respectively. Dynamic water-repellent models were constructed. The stable low surface energy and dynamic water- and oil-repellent properties of these synthesized fluorinated polymers with short perfluorobutyl side chains were attributed to the synergetic effect of amorphous fluorinated side chains in perfluoroalkyl acrylate and crystalline hydrocarbon pendant groups in stearyl acrylate. Outstanding water- and oil-repellent properties of fabrics and any other substrates could be achieved by a facile dip-coating treatment using a fluorinated copolymer dispersion. As a result, we believe that our prepared fluorinated copolymers are potential candidates to replace the fluoroalkylated polymers with long perfluorinated chains in nonstick and self-cleaning applications in our daily life.

  2. Thermal performances of vertical hybrid PV/T air collector

    NASA Astrophysics Data System (ADS)

    Tabet, I.; Touafek, K.; Bellel, N.; Khelifa, A.

    2016-11-01

    In this work, numerical analyses and the experimental validation of the thermal behavior of a vertical photovoltaic thermal air collector are investigated. The thermal model is developed using the energy balance equations of the PV/T air collector. Experimental tests are conducted to validate our mathematical model. The tests are performed in the southern Algerian region (Ghardaïa) under clear sky conditions. The prototype of the PV/T air collector is vertically erected and south oriented. The absorber upper plate temperature, glass cover temperature, air temperature in the inlet and outlet of the collector, ambient temperature, wind speed, and solar radiation are measured. The efficiency of the collector increases with increase in mass flow of air, but the increase in mass flow of air reduces the temperature of the system. The increase in efficiency of the PV/T air collector is due to the increase in the number of fins added. In the experiments, the air temperature difference between the inlet and the outlet of the PV/T air collector reaches 10 ° C on November 21, 2014, the interval time is between 10:00 and 14:00, and the temperature of the upper plate reaches 45 ° C at noon. The mathematical model describing the dynamic behavior of the typical PV/T air collector is evaluated by calculating the root mean square error and mean absolute percentage error. A good agreement between the experiment and the simulation results is obtained.

  3. Engineering with uncertainty: monitoring air bag performance.

    PubMed

    Wetmore, Jameson M

    2008-06-01

    Modern engineering is complicated by an enormous number of uncertainties. Engineers know a great deal about the material world and how it works. But due to the inherent limits of testing and the complexities of the world outside the lab, engineers will never be able to fully predict how their creations will behave. One way the uncertainties of engineering can be dealt with is by actively monitoring technologies once they have left the development and production stage. This article uses an episode in the history of automobile air bags as an example of engineers who had the foresight and initiative to carefully track the technology on the road to discover problems as early as possible. Not only can monitoring help engineers identify problems that surface in the field, it can also assist them in their efforts to mobilize resources to resolve problem.

  4. Criteria for Side-Force Control in Air-to-Ground Target Acquisition and Tracking

    NASA Technical Reports Server (NTRS)

    Sammonds, Robert I.; McNeill, Walter E.; Bunnell, John W.

    1982-01-01

    A moving-base simulator experiment conducted at Ames Research Center demonstrated that a wings-level-turn control mode improved flying qualities for air-to-ground weapons delivery compared with those of a conventional aircraft. Evaluations of criteria for dynamic response for this system have shown that pilot ratings correlate well with equivalent time constant of the initial response and with system bandwidth. Ranges of this time constant, as well as digital-system transport delays and lateral-acceleration control authorities that encompassed level 1 through level 3 handling qualities, were determined.

  5. Performance verification of an air solar collector

    NASA Technical Reports Server (NTRS)

    Miller, D. C.; Romaker, R. F.

    1979-01-01

    Procedures and results of battery of qualification tests performed by independent certification agency on commercial solar collector are presented in report. Reported results were used as basis in judging collector suitable for field installation in residential and commerical buildings.

  6. Laboratory Performance Testing of Residential Window Air Conditioners

    SciTech Connect

    Winkler, J.; Booten, C.; Christensen, D.; Tomerlin, J.

    2013-03-01

    Window air conditioners are the dominant cooling product for residences, in terms of annual unit sales. They are inexpensive, portable and can be installed by the owner. For this reason, they are an attractive solution for supplemental cooling, for retrofitting air conditioning into a home which lacks ductwork, and for renters. Window air conditioners for sale in the United States are required to meet very modest minimum efficiency standards. Four window air conditioners' performance were tested in the Advanced HVAC Systems Laboratory on NREL's campus in Golden, CO. In order to separate and study the refrigerant system's performance, the unit's internal leakage pathways, the unit's fanforced ventilation, and the leakage around the unit resulting from installation in a window, a series of tests were devised that focused on each aspect of the unit's performance. These tests were designed to develop a detailed performance map to determine whole-house performance in different climates. Even though the test regimen deviated thoroughly from the industry-standard ratings test, the results permit simple calculation of an estimated rating for both capacity and efficiency that would result from a standard ratings test. Using this calculation method, it was found that the three new air conditioners' measured performance was consistent with their ratings. This method also permits calculation of equivalent SEER for the test articles. Performance datasets were developed across a broad range of indoor and outdoor operating conditions, and used them to generate performance maps.

  7. Performance Assessment of Sodium to Air Finned Heat Exchanger for FBR

    SciTech Connect

    Noushad, I.B.; Ellappan, T.R.; Rajan, K.K.; Rajan, M.; Vaidyanathan, G.; Vinod, V.; Suresh Kumar, V.A.

    2006-07-01

    In pool type Fast Breeder Reactors (FBR) a passive Safety Grade Decay Heat Removal (SGDHR) system removes decay heat produced in the core when normal heat removal path through steam water system is not available. This is essential to maintain the core temperatures within limits. A Decay Heat Exchanger (DHX) picks the heat from the pool and transfers the heat to atmosphere through sodium to Air Heat Exchanger (AHX) situated at high elevation. Due to the temperature differences existent in the system density differences are generated causing a buoyant convective heat transfer. The system is completely passive as primary sodium, secondary sodium and air flows under natural convection. DHX is a sodium to sodium counter flow heat exchanger with primary sodium on shell side and secondary sodium on tube side. AHX is a cross flow heat exchanger with sodium on tube side and air flows in cross flow across the finned tubes. Capacity of a single loop of SGDHR is 8 MW. Four such loops are available for the decay heat removal. It has been seen that the decay heat removal to a large extent depends on the AHX performance. AHX tested have shown reduced heat removal capacity much as 30 to 40%, essentially due to the bypassing of the finned tubes by the air. It was felt that a geometrically similar AHX be tested in sodium. Towards this a 2 MW Sodium to air heat exchanger (AHX) was tested in the Steam Generator Test Facility (SGTF) constructed at Indira Gandhi Center for Atomic Research (IGCAR), Kalpakkam. The casing arrangement of the AHX was designed to minimise bypassing of air. (authors)

  8. Performance of Booster Seats in Side Impacts: Effect of Adjacent Passengers and Isofix Attachment

    PubMed Central

    Charlton, Judith L.; Fildes, Brian; Taranto, David; Laemmle, Ronald; Smith, Stuart; Clark, Anthony; Holden, GM

    2007-01-01

    This study examined the performance of a booster seat in different seating configurations in side-impact hyGe sled tests (crash severity 30 km/h) with two attachment systems: a standard seatbelt and ISOfix (rigid). The objectives of the study were twofold: (i) to identify the relative benefits of ISOfix attachment compared with seatbelt attachment of a near-side booster seat in a 3-abreast seating configuration with adjacent occupants in child restraints (CRS); and (ii) to examine the effects of 3-abreast seating configurations compared with no adjacent passengers on booster seat crash protection characteristics. Overall, the findings confirmed the superior performance of the rigid anchorages in reducing lateral motion of the booster as well as the two adjacent CRS. However, the expected benefits of the rigid attachment in reducing head accelerations were not uniformly observed across the three occupants/seating positions and also appeared to be influenced by seating configuration (3-abreast versus no adjacent occupant). Further research is warranted to explore the applicability of the findings for different CRS types and seating configurations. PMID:18184490

  9. An air gap moderates the performance of nanowire array transistors

    NASA Astrophysics Data System (ADS)

    Yang, Tong; Mehta, Jeremy S.; Mativetsky, Jeffrey M.

    2017-03-01

    Solution-processed nanowires are promising for low-cost and flexible electronics. When depositing nanowires from solution, due to stacking of the nanowires, an air gap exists between the substrate and much of the active material. Here, using confocal Raman spectroscopy, we quantify the thickness of the air gap in transistors comprising organic semiconductor nanowires. The average air gap thickness is found to be unexpectedly large, being at least three times larger than the nanowire diameter, leading to a significant impact on transistor performance. The air gap acts as an additional dielectric layer that reduces the accumulation of charge carriers due to a gate voltage. Conventional determination of the charge carrier mobility ignores the presence of an air gap, resulting in an overestimate of charge carrier accumulation and an underestimate of charge carrier mobility. It is shown that the larger the air gap, the larger the mobility correction (which can be greater than an order of magnitude) and the larger the degradation in on–off current ratio. These results demonstrate the importance of minimizing the air gap and of taking the air gap into consideration when analyzing the electrical performance of transistors consisting of stacked nanowires. This finding is applicable to all types of stacked one-dimensional materials including organic and inorganic nanowires, and carbon nanotubes.

  10. An air gap moderates the performance of nanowire array transistors.

    PubMed

    Yang, Tong; Mehta, Jeremy S; Mativetsky, Jeffrey M

    2017-03-24

    Solution-processed nanowires are promising for low-cost and flexible electronics. When depositing nanowires from solution, due to stacking of the nanowires, an air gap exists between the substrate and much of the active material. Here, using confocal Raman spectroscopy, we quantify the thickness of the air gap in transistors comprising organic semiconductor nanowires. The average air gap thickness is found to be unexpectedly large, being at least three times larger than the nanowire diameter, leading to a significant impact on transistor performance. The air gap acts as an additional dielectric layer that reduces the accumulation of charge carriers due to a gate voltage. Conventional determination of the charge carrier mobility ignores the presence of an air gap, resulting in an overestimate of charge carrier accumulation and an underestimate of charge carrier mobility. It is shown that the larger the air gap, the larger the mobility correction (which can be greater than an order of magnitude) and the larger the degradation in on-off current ratio. These results demonstrate the importance of minimizing the air gap and of taking the air gap into consideration when analyzing the electrical performance of transistors consisting of stacked nanowires. This finding is applicable to all types of stacked one-dimensional materials including organic and inorganic nanowires, and carbon nanotubes.

  11. Performance of underfloor air distribution: Results of a field study

    SciTech Connect

    Fisk, William; Faulkner, David; Sullivan, Douglas

    2004-09-02

    Underfloor air distribution (UFAD) is a new method of supplying heated or cooled air throughout a building. Reported advantages of UFAD include easy relocation of air supply diffusers, energy savings, and improved indoor air quality (IAQ). We measured several aspects of the performance of an UFAD system installed in a medium-size office building. The measured air change effectiveness was very close to unity, which is comparable to that measured in buildings with typical overhead air distribution. The pollutant removal efficiency for carbon dioxide was 13 percent higher than expected in a space with well-mixed air, suggesting a 13 percent reduction in exposures to occupant generated pollutants. The increase in indoor air temperatures with height above the floor was only 1 to 2 C (2-4 F). This amount of thermal stratification could reduce the sensible energy requirements for cooling of outdoor air by approximately 10 percent. The occupants level of satisfaction with thermal conditions w as well above average and this high satisfaction rating could possibly be due, in all or part, to the use of a UFAD system. The results of this study provide some evidence of moderate energy and IAQ-related benefits of UFAD. Before general conclusions are drawn, the benefits need to be confirmed in other studies.

  12. Performance investigation of side-coupled interlaced symmetric-shaft-shape photonic crystal sensor arrays

    NASA Astrophysics Data System (ADS)

    Fu, Zhongyuan; Zhou, Jian; Huang, Lijun; Sun, Fujun; Tian, Huiping

    2016-12-01

    We design symmetric-shaft-shape photonic crystal sensor arrays (SSPhCSAs) which can be used in refractive index sensing, and the performance of the structure is investigated. The structure consists of four symmetric-shaft-shape photonic crystal (SSPhC) cavities side-coupled to a W1 photonic crystal (PhC) waveguide. Each cavity has slightly different cavity spacing with different resonant frequency. By using two dimensional finite-difference time-domain (2D-FDTD) method, the simulation result obtained indicates the performance of the sensor arrays. The sensitivities of the four sensor units are 178, 252, 328 and 398 nm/RIU, respectively, with the detection limit of 10-3. The crosstalk lower than 20 dB is obtained.

  13. Air Force Job Performance Appraisal System.

    DTIC Science & Technology

    1984-11-01

    Robinson , J. Interaction modeling: A new concept in supervisory training. Training and Development Journal, February 1976, 30(2), 20-33. Campbell, J. P...were required for 72 evaluations submittd. V THE OVERALL PERFORMANCE RATING (ds descrilwdin the rating scalel IS BASED UPON THF [MPLOYF E’S PEni OfIMAN

  14. Performance evaluation of an air solar collector

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Indoor tests on signal-glazed flat-plate collector are described in report. Marhsall Space Flight Center solar simulator is used to make tests. Test included evaluations on thermal performance under various combinations of flow rate, incident flux, inlet temperature, and wind speed. Results are presented in graph/table form.

  15. Performance of underfloor air distribution in a fieldsetting

    SciTech Connect

    Fisk, W.J.; Faulkner, D.; Sullivan, D.P.; Chao, C.; Wan, M.P.; Zagreus, L.; Webster, T.

    2005-10-01

    Underfloor air distribution (UFAD) is a new method of supplying heated or cooled air throughout a building. Reported advantages of UFAD include energy savings and improved indoor air quality (IAQ). We measured several aspects of the performance of an UFAD system installed in a medium-size office building. The measured air change effectiveness was very close to unity, which is comparable to that measured in buildings with typical overhead air distribution. The pollutant removal efficiency for carbon dioxide was 13% higher than expected in a space with well-mixed air, suggesting a 13% reduction in exposures to occupant generated pollutants. The increase in indoor air temperatures with height above the floor was only 1 to 2 C. This amount of thermal stratification could reduce the sensible energy requirements for cooling of outdoor air by approximately 10%. The occupant's level of satisfaction with thermal conditions was well above average and this high satisfaction rating could possibly be due, in all or part, to the use of a UFAD system. The results of this study provide some evidence of moderate energy and IAQ-related benefits of UFAD. Before general conclusions are drawn, the benefits need to be confirmed in other studies.

  16. Laboratory performance of alternating pressure air mattresses component and sequelae.

    PubMed

    Bain, Duncan

    The performance of three different alternating pressure air mattresses with different geometries of air cell were compared (Nimbus 3, Heritage, Tamora Plus), using simple performance indices based on pressure mapping. The aim of this study was to examine the effect on performance of elevating the backrest and thigh section of the bed into sitting position. Ten healthy volunteers of various sizes were pressure-mapped over the full pressure cycle on three alternating pressure air mattresseses with differing cell geometries. This was then repeated with the beds profiled to a sitting position. Performance of the alternating pressure air mattresses in terms of their ability to redistribute pressure dynamically was assessed in the different positions. The different alternating pressure air mattresses performed similarly with the bed in the lying flat position, but smaller cells appeared to be more effective in the sitting position. A conclusion was made that cell geometry may have an effect on the ability of the mattress to achieve alternating behaviour in the sitting position.

  17. The Segmented Aperture Interferometric Nulling Testbed (SAINT) I: overview and air-side system description

    NASA Astrophysics Data System (ADS)

    Hicks, Brian A.; Lyon, Richard G.; Petrone, Peter; Ballard, Marlin; Bolcar, Matthew R.; Bolognese, Jeff; Clampin, Mark; Dogoda, Peter; Dworzanski, Daniel; Helmbrecht, Michael A.; Koca, Corina; Shiri, Ron

    2016-07-01

    This work presents an overview of the Segmented Aperture Interferometric Nulling Testbed (SAINT), a project that will pair an actively-controlled macro-scale segmented mirror with the Visible Nulling Coronagraph (VNC). SAINT will incorporate the VNC's demonstrated wavefront sensing and control system to refine and quantify end-to-end high-contrast starlight suppression performance. This pathfinder testbed will be used as a tool to study and refine approaches to mitigating instabilities and complex diffraction expected from future large segmented aperture telescopes.

  18. Performance evaluation of selected U.S. utility commercial lighting demand-side management programs

    SciTech Connect

    Chen, T.; Yu, O.S.

    1997-10-01

    This article selects 18 commercial lighting demand-side management programs of electric utilities in the United States and evaluates their performance. It first uses four conventional measures, i.e., rate impact measurement, total resource cost, total utility cost, and total customer cost, to analyze the costs and benefits of each program. Although all programs achieve good benefit to cost ratios under each measure, the rankings are not always consistent, i.e., a program`s ranking in one measure is not always the same as in another measure. To provide a unified basis for comparison, the authors use a mathematical programming model--the data envelopment analysis (DEA) model--to integrate the results of these four conventional measures for each program. Based on the DEA results, programs of Southern California Edison, New York State Electric and Gas, and Potomac Electric Power produce the best overall performance, followed by Central Maine Power, Pacific Gas and Electric, and Central Vermont Public Service. Finally, this article discusses the implications of the DEA results, which can serve as an effective means for performance benchmarking.

  19. High Performance Cathodes for Li-Air Batteries

    SciTech Connect

    Xing, Yangchuan

    2013-08-22

    The overall objective of this project was to develop and fabricate a multifunctional cathode with high activities in acidic electrolytes for the oxygen reduction and evolution reactions for Li-air batteries. It should enable the development of Li-air batteries that operate on hybrid electrolytes, with acidic catholytes in particular. The use of hybrid electrolytes eliminates the problems of lithium reaction with water and of lithium oxide deposition in the cathode with sole organic electrolytes. The use of acid electrolytes can eliminate carbonate formation inside the cathode, making air breathing Li-air batteries viable. The tasks of the project were focused on developing hierarchical cathode structures and bifunctional catalysts. Development and testing of a prototype hybrid Li-air battery were also conducted. We succeeded in developing a hierarchical cathode structure and an effective bifunctional catalyst. We accomplished integrating the cathode with existing anode technologies and made a pouch prototype Li-air battery using sulfuric acid as catholyte. The battery cathodes contain a nanoscale multilayer structure made with carbon nanotubes and nanofibers. The structure was demonstrated to improve battery performance substantially. The bifunctional catalyst developed contains a conductive oxide support with ultra-low loading of platinum and iridium oxides. The work performed in this project has been documented in seven peer reviewed journal publications, five conference presentations, and filing of two U.S. patents. Technical details have been documented in the quarterly reports to DOE during the course of the project.

  20. Analysis of the performance of an air-water heat pump: Regulation of intrinsic performances

    NASA Astrophysics Data System (ADS)

    Martin-Neuville, H.; Reybillet, M.; Patureau, J. P.

    Improvements for an electrical compressor heat pump of around 12 kW with air as a heat source are examined. To test the heat pump under different weather conditions a test loop has been built. On the condenser side a water circuit with several capacities and heat exchangers simulates the thermal behavior of a 120 sq m dwelling. A commercial domestic heat pump was extensively tested. The instantaneous performance of the heat pump agreed well with the data claimed by the manufacturer. The annual energy saving, however, was significantly less due to the following: (1) loss of efficiency caused by defrosting cycles; (2) loss of efficiency due to inadequate thermal load matching between the heat pump and the house. It was shown that control of the condensing temperature can bring energy savings of 10 percent. This could probably also be realized by load matching with a compressor with a variable speed; and (3) the inefficient operation of components such as the evaporator and the condenser heat exchangers and the expansion valve. Optimization could lead to a considerable improvement. Modifications in the compressor are proposed which may lead to an increase in efficiency to 60 or 70 percent.

  1. Do conventional monitoring practices indicate in situ air sparging performance?

    SciTech Connect

    Johnson, P.C.; Johnson, R.L.; Neaville, C.; Hansen, E.E.; Stearns, S.M.; Dortch, I.J.

    1995-12-31

    Short-term pilot tests play a key role in the selection and design of in situ air sparging systems. Most pilot tests are less than 24 h in duration and consist of monitoring changes in dissolved oxygen, water levels in wells, soil gas pressures, and soil gas contaminant concentrations while air is injected into the aquifer. These parameters are assumed to be indicators of air sparging feasibility and performance, and are also used in the design of full-scale systems. In this work the authors assess the validity of this critical assumption. Data are presented from a study site where a typical pilot-scale short-term test was conducted, followed by continued operation of a full-scale system for 110 days. Conventional sampling practices were augmented with more discrete and detailed assessment methods. In addition, a tracer gas was used to better understand air distributions, vapor flow paths, and vapor recovery efficiency. The data illustrate that conclusions regarding the performance and applicability of air sparging at the study site vary significantly depending on the monitoring approach used. There was no clear correlation between short-term pilot-test data and extended system performance when using data collected only from conventional groundwater monitoring wells. Attention is focused on petroleum hydrocarbons.

  2. Ergogenic aids: a review of basic science, performance, side effects, and status in sports.

    PubMed

    Tokish, John M; Kocher, Mininder S; Hawkins, Richard J

    2004-09-01

    The use of drugs and supplements to enhance performance has become a part of mainstream athletics. Many team physicians and sports medicine practitioners are unfamiliar with the benefits and risks of these products and thus are unable to educate young athletes on this topic. In spite of numerous reports on the health risks of anabolic steroid use, 1 to 3 million Americans have used them. Human growth hormone has been tried by up to 5% of 10th graders, although no scientific study has shown that it is an effective performance-enhancing drug. Amphetamines and similar compounds may be the most widely abused drug in baseball; recently, they have come under increased scrutiny in sport. Erythropoietin is a highly effective aerobic enhancer that has been linked to multiple deaths in cyclists and other endurance athletes. The neutraceutical industry, led by supplements such as creatine, ephedra, and androstenedione, remains unregulated by the Food and Drug Administration and has serious issues with quality and side effects. An understanding of these products is essential for the sports medicine practitioner to provide sound, safe advice to the athlete.

  3. Negative air ion effects on human performance and physiological condition.

    PubMed

    Buckalew, L W; Rizzuto, A P

    1984-08-01

    Beneficial effects of exposure to negative air ions have been suggested, to include improved performance, mood, attention, and physiological condition. Existing support is clouded by methodological problems of control and standardization in treatment and equipment. This study investigated effects of negative ions produced by a commercially marketed air purification device on grip magnitude, coding, motor dexterity, reaction time, tracking, pulse, blood pressure, and temperature. Two groups of 12 males were exposed to 6 continuous h of either negative or "normal" ion environments under a double blind condition. Repeated measures (0,3,6 h) on each variable were obtained. MANOVA applied to change scores revealed no differences between groups, and 0 vs. 3 and 0 vs. 6-h group differences showed no significant alteration in any measure. Negative ions generated by an air purification device were concluded to produce no general or specific alteration of cognitive or psychomotor performance or physiological condition.

  4. Performance of a photovoltaically powered air-conditioning system

    SciTech Connect

    Kern, Jr, E. C.; Millner, A. R.

    1980-01-01

    A vapor-compression air conditioner coupled directly to a photovoltaic array is discussed. Previous analyses of such a system are reviewed, and a development system designed to test the concept is described. Preliminary experiments indicate that the performance of this initial system falls considerably short of analytic expectations.

  5. Thermal performance of a hot-air solar collector

    NASA Technical Reports Server (NTRS)

    1978-01-01

    Report contains procedures and results of thermal-performance tests on double-glazed air solar collector. Four types of tests were carried out including thermal-efficiency and stagnation tests, collector time-constant tests to assess effects of transients, and incident-angle modifier tests. Data are presented in tables and as graphs and are discussed and analyzed.

  6. Indoor air quality standards of performance applications guide

    SciTech Connect

    Linder, R.J.; Dorgan, C.B.; Dorgan, C.E.

    1999-07-01

    This paper discusses the development and application of standards of performance (SOPs) for HVAC and R equipment, plumbing systems, and building envelope systems in relation to maintaining acceptable indoor air quality (IAQ) in buildings. The utilization of the SOP procedure, developed in ASHRAE Research Project 853, will aid in the proper operation of systems and verify that acceptable building IAQ levels are obtained.

  7. Next Generation Solvent Performance in the Modular Caustic Side Solvent Extraction Process - 15495

    SciTech Connect

    Smith, Tara E.; Scherman, Carl; Martin, David; Suggs, Patricia

    2015-01-14

    Changes to the Modular Caustic Side Solvent Extraction Unit (MCU) flow-sheet were implemented in the facility. Implementation included changing the scrub and strip chemicals and concentrations, modifying the O/A ratios for the strip, scrub, and extraction contactor banks, and blending the current BoBCalixC6 extractant-based solvent in MCU with clean MaxCalix extractant-based solvent. During the successful demonstration period, the MCU process was subject to rigorous oversight to ensure hydraulic stability and chemical/radionuclide analysis of the key process tanks (caustic wash tank, solvent hold tank, strip effluent hold tank, and decontaminated salt solution hold tank) to evaluate solvent carryover to downstream facilities and the effectiveness of cesium removal from the liquid salt waste. Results indicated the extraction of cesium was significantly more effective with an average Decontamination Factor (DF) of 1,129 (range was 107 to 1,824) and that stripping was effective. The contactor hydraulic performance was stable and satisfactory, as indicated by contactor vibration, contactor rotational speed, and flow stability; all of which remained at or near target values. Furthermore, the Solvent Hold Tank (SHT) level and specific gravity was as expected, indicating that solvent integrity and organic hydraulic stability were maintained. The coalescer performances were in the range of processing results under the BOBCalixC6 flow sheet, indicating negligible adverse impact of NGS deployment. After the Demonstration period, MCU began processing via routine operations. Results to date reiterate the enhanced cesium extraction and stripping capability of the Next Generation Solvent (NGS) flow sheet. This paper presents process performance results of the NGS Demonstration and continued operations of MCU utilizing the blended BobCalixC6-MaxCalix solvent under the NGS flowsheet.

  8. Air Defense: A Computer Game for Research in Human Performance.

    DTIC Science & Technology

    1981-07-01

    AD-A102 725 NAVY PERSONNEL RESEARCH AND DEVELOPMENT CENTER SAN DETC F/6 5/10 AIR DEFENSE: A COMPUTER GAME FOR RESEARCH IN HUMAN PERFORMANCE.(U) JUL... RESEARCH IN HUMAN PERFORMANCE R ichard T. Kelly Frank L. Greitzer Ramon L. Hershman *i Reviewcd by . ,’. Kochler Released by James 1:. Kelly, Jr. Ccr ni ng...Oflicer Navy Personnel Research and 0evelopment Center San Diego, California 92152 UNCLASSIFED SECURITY CLASSIFICATION OF THIS PAGE (Whlen. Dole

  9. Performance assessment of novel side firing safe tips for endodontic applications

    NASA Astrophysics Data System (ADS)

    George, Roy; Walsh, Laurence J.

    2011-04-01

    During root canal or periodontal treatment, directing laser energy onto the walls of the root canal is essential for effective disinfection. This study assessed the performance of four different fiber modifications that have increased lateral emission, including three designs with safe tips to reduce irradiation directed toward the root apex. Free-running pulsed infrared lasers (Nd:YAG, Er:YAG, and Er,Cr:YSGG) and a diode laser (980 nm) were used in combination with plain ended (forward emitting) laser fibers; conical laser fibers, side firing honeycomb pattern fibers without a safe end; honeycomb fibers with silver coated ends, conical fibers with selectively abraded tips, and selectively abraded honeycomb fibers with silver coated tips (20 fibers for each laser type). Laser emissions forward and laterally were measured, and digital photographs and thermally sensitive paper used to record the emission profiles. Thermochromic dyes painted onto the root surface of an extracted tooth were used to explore the distribution of laser energy with different tips designs. All three safe tipped ends gave reduced emissions in the forward direction (range 17-59%), but had similar lateral emission characteristics. Fiber designs with reduced forward emission may be useful for various dental laser procedures.

  10. Off-side front foot drives in men's high performance cricket.

    PubMed

    Stuelcken, M C; Portus, M R; Mason, B R

    2005-01-01

    We investigated the techniques used by nine right-handed, international batsmen to perform front foot off-side drives in first class and international matches. All strokes were captured using two synchronised high-speed video cameras; nine were selected for kinematic analysis. These movement sequences were then manually digitised at a sampling frequency of 125 Hz using APAS motion analysis software. The results of this study indicated that the batsmen used movement patterns that enabled important aspects of stroke production, such as the front stride and the downswing of the bat, to be delayed so that additional information from ball flight could be assimilated. Front upper limb segments were constrained to work in a unitary fashion, with the peak horizontal end point speed of each segment occurring almost simultaneously just before impact. It has been suggested that these strategies serve to enhance stroke accuracy. Other aspects of their techniques included a distinctively looped bat path, a front foot placement that occurred only just before impact, and a front ankle that was positioned well inside the line of the ball at impact. Various technical parameters, such as the alignment of the trunk relative to ground and the continuous flow of the bat between the backswing and downswing, were similar to findings in previous batting research. Other characteristics of stroke production not previously addressed, including the path of the bat and the timing of the front stride, may challenge some long held beliefs evident in current coaching literature.

  11. Performance testing and analysis of vertical ambient air vaporizers

    NASA Astrophysics Data System (ADS)

    Pandey, A. S.; Singh, V. N.; Shah, M. I.; Acharya, D. V.

    2017-02-01

    Ambient air vaporizers are used to regasify cryogenic liquids at extremely low temperature (below -153°C). Frost formation occurs on it due to large temperature difference between ambient air and cryogenic fluid. Frosting induces additional load on equipment and reduces its heat transfer effectiveness. Hence, mechanical and thermal design of vaporizers account for frosting. An experimental set-up has been designed and effects of flow rate and ground clearance on the performance of ambient air vaporizers are evaluated. The flow rate is increased from the rated capacity of 500 Nm3/h to 640 Nm3/h and ground clearance is reduced from 500 mm to 175 mm. The above variations reduce the time duration for which gaseous nitrogen is delivered at temperature higher than 10.1°C (desired). Hence duty cycle reduces from eight hours to five hours. The other factors affecting performance such as fin configuration, fluid type, fluid pressure, intermittent flow nature and climatic conditions are assumed to be constant over the test duration. The decrement in outlet gas temperature (from 38 °C to 10.1°C) with corresponding increment in frost thickness leads to deterioration of performance of ambient air vaporizers.

  12. Assessment of performance of UV sterilizer for room air bacteria.

    PubMed

    Joshi, P V

    2002-02-01

    Paper presents a technique for performance of UV sterilizer for room air bacteria. Patterns of decay of room air bacteria concentration during sterilization and build-up there after as a function of time is studied. Decay process seems to follow exponential pattern. Half-lives during decay are estimated. For single sterilizer unit with a dose of 16 W the decay half-life is around 8.6 min. For the dose of 32 W (2 sterilizers), half-life is estimated to be 6.18 min. The removal rates of room air bacteria due to sterilizer are compared with the natural decay of aerosols at steady state. The importance of decay half-life in the assessment has been stated. The bacteria concentration buildup process after putting off the sterilizers seems to be sigmoidal in nature. The buildup half-life is estimated to be around 53 min for present experimental conditions.

  13. AirJump: Using Interfaces to Instantly Perform Simultaneous Extractions

    PubMed Central

    2016-01-01

    Analyte isolation is an important process that spans a range of biomedical disciplines, including diagnostics, research, and forensics. While downstream analytical techniques have advanced in terms of both capability and throughput, analyte isolation technology has lagged behind, increasingly becoming the bottleneck in these processes. Thus, there exists a need for simple, fast, and easy to integrate analyte separation protocols to alleviate this bottleneck. Recently, a new class of technologies has emerged that leverages the movement of paramagnetic particle (PMP)-bound analytes through phase barriers to achieve a high efficiency separation in a single or a few steps. Specifically, the passage of a PMP/analyte aggregate through a phase interface (aqueous/air in this case) acts to efficiently “exclude” unbound (contaminant) material from PMP-bound analytes with higher efficiency than traditional washing-based solid-phase extraction (SPE) protocols (i.e., bind, wash several times, elute). Here, we describe for the first time a new type of “exclusion-based” sample preparation, which we term “AirJump”. Upon realizing that much of the contaminant carryover stems from interactions with the sample vessel surface (e.g., pipetting residue, wetting), we aim to eliminate the influence of that factor. Thus, AirJump isolates PMP-bound analyte by “jumping” analyte directly out of a free liquid/air interface. Through careful characterization, we have demonstrated the validity of AirJump isolation through comparison to traditional washing-based isolations. Additionally, we have confirmed the suitability of AirJump in three important independent biological isolations, including protein immunoprecipitation, viral RNA isolation, and cell culture gene expression analysis. Taken together, these data sets demonstrate that AirJump performs efficiently, with high analyte yield, high purity, no cross contamination, rapid time-to-isolation, and excellent reproducibility

  14. Dry/wet performance of a plate-fin air-cooled heat exchanger with continuous corrugated fins

    SciTech Connect

    Hauser, S.G.; Kreid, D.K.; Johnson, B.M.

    1981-01-01

    The performance and operating characteristics of a plate-fin heat exchanger in dry/wet or deluge operations was experimentally determined. Development of the deluge heat/mass transfer model continued. The experiments were conducted in a specially-designed wind tunnel at the PNL. Air that was first heated and humidified to specified conditions was circulated at a controlled rate through a 2 ft x 6 ft heat exchanger module. The heat exchanger used in the tests was a wavy surface, plate fin on tube configuration. Hot water was circulated through the tubes at high flow rates to maintain an essentially isothermal condition on the tube side. Deionized water sprayed on the top of the vertically oriented plate fins was collected at the bottom of the core and recirculated. Instrumentation was provided for measurement of flow rates and thermodynamic conditions in the air, in the core circulation water, and in the deluge water. Measurements of the air side pressure drop and heat rejection rate were made as a function of air flow rate, air inlet temperature and humidity, deluge water flow rate, and the core inclination from the vertical. An overall heat transfer coefficient and an effective deluge film convective coefficient was determined. The deluge model, for predicting heat transfer from a wet finned heat exchanger was further developed and refined, and a major extension of the model was formulated that permits simultaneous calculation of both the heat transfer and evaporation rates from the wetted surface. The experiments showed an increase in the heat rejection rate due to wetting, accompanied by a proportional increase in the air side pressure drop. For operation at the same air side pressure drop, the enhancement ratio Q/sub w//Q/sub d/ varied between 2 and 5 for the conditions tested. Thus, the potential enhancement of heat transfer due to wetting can be substantial.

  15. Implications of air pollution effects on athletic performance

    SciTech Connect

    Pierson, W.E.; Covert, D.S.; Koenig, J.Q.; Namekata, T.; Kim, Y.S.

    1986-06-01

    Both controlled human studies and observational studies suggest that air pollution adversely affects athletic performance during both training and competition. The air pollution dosage during exercise is much higher than during rest because of a higher ventilatory rate and both nasal and oral breathing in the former case. For example, sulfur dioxide, which is a highly water-soluble gas, is almost entirely absorbed in the upper respiratory tract during nasal breathing. However, with oral pharyngeal breathing, the amount of sulfur dioxide that is absorbed is significantly less, and with exercise and oral pharyngeal breathing a significant decrease in upper airway absorption occurs, resulting in a significantly larger dosage of this pollutant being delivered to the tracheobronchial tree. Recently, several controlled human studies have shown that the combination of exercise and pollutant exposure (SO/sub 2/ or O/sub 3/) caused a marked bronchoconstriction and reduced ventilatory flow when compared to pollution exposure at rest. In a situation like the Olympic Games where milliseconds and millimeters often determine the success of athletes, air pollution can be an important factor in affecting their performance. This paper examines possible impacts of air pollution on athletic competition.

  16. Review: Implications of air pollution effects on athletic performance

    NASA Astrophysics Data System (ADS)

    Pierson, William E.; Covert, David S.; Koenig, Jane Q.; Namekata, Tsukasa; Kim, Yoon Shin

    Both controlled human studies and observational studies suggest air pollution adversely affects athletic performance during both training and competition. The air pollution dosage during exercise is much higher than during rest because of a higher ventilatory rate and both nasal and oral breathing in the former case. For example, SO 2 which is a highly water soluble gas, is almost entirely absorbed in the upper respiratory tract during nasal breathing. However, with oral pharyngeal breathing, the amount of sulfur dioxide that is absorbed is significantly less, and with exercise and oral pharyngeal breathing a significant decrease in upper airway absorption occurs, resulting in a significantly larger dosage of this pollutant being delivered to the tracheobronchial tree. Recently, several controlled human studies have shown that the combination of exercise and pollutant exposure (SO 2 or O 3) caused a marked bronchoconstriction and reduced ventilatory flow when compared with pollution exposure at rest. In a situation like the Olympic Games where ms and mm often determine success of athletes, air pollution can be an important factor in affecting their performance. This paper examines possible impacts of air pollution on athletic competition.

  17. Effect of air pollution on athlete health and performance.

    PubMed

    Rundell, Kenneth William

    2012-05-01

    Unfavourable effects on the respiratory and the cardiovascular systems from short-term and long-term inhalation of air pollution are well documented. Exposure to freshly generated mixed combustion emissions such as those observed in proximity to roadways with high volumes of traffic and those from ice-resurfacing equipment are of particular concern. This is because there is a greater toxicity from freshly generated whole exhaust than from its component parts. The particles released from emissions are considered to cause oxidative damage and inflammation in the airways and the vascular system, and may be related to decreased exercise performance. However, few studies have examined this aspect. Several papers describe deleterious effects on health from chronic and acute air pollution exposure. However, there has been no research into the effects of long-term exposure to air pollution on athletic performance and a paucity of studies that describe the effects of acute exposure on exercise performance. The current knowledge of exercising in the high-pollution environment and the consequences that it may have on athlete performance are reviewed.

  18. Experimental investigation on film cooling performance of pressure side in annular cascades

    NASA Astrophysics Data System (ADS)

    Li, Guoqing; Deng, Hongwu

    2011-06-01

    Experimental investigations were conducted to study the film cooling performance in a low speed annular cascades using Thermochromic Liquid Crystal (TLC) technique. The test blade was placed in the second stage, where 18 blades were installed with chord length of 124.3 mm and height of 99 mm. A film hole with diameter of 4 mm, angled 28° to the tangential of the pressure surface in streamwise, was set in the middle span of the blade. The Reynolds number based on the outlet mainstream velocity and the blade chord length of the second stage varied from 1.52×105 to 2.00×105. All measurements were made with the blowing ratio varying from 0.3 to 3.0. Air and CO2 worked as coolant to achieve the coolant-to-mainstream density ratio of 1.03 and 1.57. The results show that the film coverage and cooling effectiveness scale up with the blowing ratio. Higher density ratio can generate larger film cooling coverage and effectiveness. The higher the Reynolds number, the larger the film coverage and cooling effectiveness.

  19. Working from Both Sides: Composite Metallic Semitransparent Top Electrode for High Performance Perovskite Solar Cells.

    PubMed

    Dai, Xuezeng; Zhang, Ye; Shen, Heping; Luo, Qiang; Zhao, Xingyue; Li, Jianbao; Lin, Hong

    2016-02-01

    We report herein perovskite solar cells using solution-processed silver nanowires (AgNWs) as transparent top electrode with markedly enhanced device performance, as well as stability by evaporating an ultrathin transparent Au (UTA) layer beneath the spin-coated AgNWs forming a composite transparent metallic electrode. The interlayer serves as a physical separation sandwiched in between the perovskite/hole transporting material (HTM) active layer and the halide-reactive AgNWs top-electrode to prevent undesired electrode degradation and simultaneously functions to significantly promote ohmic contact. The as-fabricated semitransparent PSCs feature a Voc of 0.96 V, a Jsc of 20.47 mA cm(-2), with an overall PCE of over 11% when measured with front illumination and a Voc of 0.92 V, a Jsc of 14.29 mA cm(-2), and an overall PCE of 7.53% with back illumination, corresponding to approximately 70% of the value under normal illumination conditions. The devices also demonstrate exceptional fabrication repeatability and air stability.

  20. Eddy covariance flux of sulfur dioxide to the sea surface: Air-side resistance to deposition of a highly soluble gas

    NASA Astrophysics Data System (ADS)

    Porter, J.; De Bruyn, W. J.; Miller, S. D.; Saltzman, E. S.

    2014-12-01

    Deposition to the sea surface represents a major atmospheric removal mechanism for sulfur dioxide and many other highly soluble products of tropospheric photochemistry. Such gases include nitric acid, ammonia, organic acids, sulfur dioxide, and highly soluble organic compounds such as methanol and acetone. The deposition of highly soluble gases is controlled by turbulent and diffusive transport on the air side of the air/sea interface. In this study, air/sea fluxes of the soluble gas sulfur dioxide (SO2 ), sensible and latent heat, and momentum were measured using eddy covariance. This was a pilot study carried out in April 2014 on Scripps pier in La Jolla, California, that was designed to assess the potential for measuring SO2 fluxes over the ocean. SO2 was detected using chemical ion mass spectrometry in negative ion mode with a sensitivity of roughly 100 Hz/ppt. The ionization scheme involved addition of ozone to a dried air stream and subsequent conversion of SO2 to the SO5 - ion. The results demonstrate the feasibility of seagoing SO2 flux measurements. Such measurements can be used to constrain the depositional velocities of soluble gases and test models for air-side resistance to air/sea gas transfer.

  1. Determinants of elite-level air rifle shooting performance.

    PubMed

    Ihalainen, S; Kuitunen, S; Mononen, K; Linnamo, V

    2016-03-01

    This study focused on identifying the most important factors determining performance in elite-level air rifle shooting technique. Forty international- and national-level shooters completed a simulated air rifle shooting competition series. From a total of 13 795 shots in 319 tests, shooting score and 17 aiming point trajectory variables were measured with an optoelectronic device and six postural balance variables were measured with force platform. Principal component analysis revealed six components in the air rifle shooting technique: aiming time, stability of hold, measurement time, cleanness of triggering, aiming accuracy, and timing of triggering. Multiple regression analysis identified four of those, namely stability of hold, cleanness of triggering, aiming accuracy, and timing of triggering as the most important predictors of shooting performance, accounting for 81% of the variance in shooting score. The direct effect of postural balance on performance was small, accounting for less than 1% of the variance in shooting score. Indirectly, the effect can be greater through a more stable holding ability, to which postural balance was correlated significantly (R = 0.55, P < 0.001). The results of the present study can be used in assessing athletes' technical strengths and weaknesses and in directing training programs on distinct shooting technical components.

  2. High-Performance Sorbents for Carbon Dioxide Capture from Air

    SciTech Connect

    Sholl, David; Jones, Christopher

    2013-03-13

    This project has focused on capture of CO{sub 2} from ambient air (“air capture”). If this process is technically and economically feasible, it could potentially contribute to net reduction of CO{sub 2} emissions in ways that are complementary to better developed techniques for CO{sub 2} from concentrated point sources. We focused on cyclic adsorption processes for CO{sub 2} capture from air in which the entire cycle is performed at moderate temperatures. The project involved both experimental studies of sorbent materials and process level modeling of cyclic air capture processes. In our experimental work, a series of amine-functionalized silica adsorbents were prepared and characterized to determine the impact of molecular architecture on CO{sub 2} capture. Some key findings were: • Amine functionalized silicas can be prepared with high enough CO{sub 2} capacities under ambient conditions to merit consideration for use in air capture processes. • Primary amines are better candidates for CO{sub 2} capture than secondary or tertiary amines, both in terms of amine efficiency for CO{sub 2} adsorption and enhanced water affinity. • Mechanistic understanding of degradation of these materials can enable control of molecular architecture to significantly improve material stability. Our process modeling work provided the first publically available cost and energy estimates for cyclic adsorption processes for air capture of CO{sub 2}. Some key findings were: • Cycles based on diurnal ambient heating and cooling cannot yield useful purities or amounts of captured CO{sub 2}. • Cycles based on steam desorption at 110 oC can yield CO{sub 2} purities of ~88%. • The energy requirements for cycles using steam desorption are dominated by needs for thermal input, which results in lower costs than energy input in the form of electricity. Cyclic processes with operational costs of less than $100 tCO{sub 2}-net were described, and these results point to process and

  3. Performance Study of a Double-Pass Thermoelectric Solar Air Collector with Flat-Plate Reflectors

    NASA Astrophysics Data System (ADS)

    Lertsatitthanakorn, C.; Rungsiyopas, M.; Therdyothin, A.; Soponronnarit, S.

    2012-06-01

    In this paper the results of the influence of flat-plate reflectors made of aluminum foil on the performance of a double-pass thermoelectric (TE) solar air collector are presented. The proposed TE solar collector with reflectors was composed of transparent glass, an air gap, an absorber plate, TE modules, a rectangular fin heat sink, and two flat-plate reflectors. The flat-plate reflectors were placed on two sides of the TE solar collector (east and west directions). The TE solar collector was installed on a one-axis sun-tracking system to obtain high solar radiation. Direct and reflected incident solar radiation heats up the absorber plate so that a temperature difference is created across the TE modules to generate a direct current. Only a small part of the absorbed solar radiation is converted to electricity, while the rest increases the temperature of the absorber plate. Ambient air flows through the heat sink located in the lower channel to gain heat. The heated air then flows to the upper channel, where it receives additional heating from the absorber plate. Improvements to the thermal energy and electrical power outputs of the system can be achieved by the use of the double-pass collector system with reflectors and TE technology. It was found that the optimum position of the reflectors is 60°, which gave significantly higher thermal energy and electrical power outputs compared with the TE solar collector without reflectors.

  4. Cold air performance of a 12.766-centimeter-tip-diameter axial-flow cooled turbine. 2: Effect of air ejection on turbine performance

    NASA Technical Reports Server (NTRS)

    Haas, J. E.; Kofskey, M. G.

    1977-01-01

    An air cooled version of a single-stage, axial-flow turbine was investigated to determine aerodynamic performance with and without air ejection from the stator and rotor blades surfaces to simulate the effect of cooling air discharge. Air ejection rate was varied from 0 to 10 percent of turbine mass flow for both the stator and the rotor. A primary-to-air ejection temperature ratio of about 1 was maintained.

  5. Children Living with Violence against Their Mothers: The Side Effects on Their Behaviour, Self-Image and School Performance

    ERIC Educational Resources Information Center

    Koutselini, Mary; Valanidou, Floria

    2014-01-01

    This paper discusses the effects of children's exposure to violence against their mothers. It particularly considers the sided-effects of this violence on the children's behaviour, self-image and school performance. The research indicates that (1) violence against women victimises not only the mothers but also their children, even if the children…

  6. Oblique view of east side mechanical additions and south side ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Oblique view of east side mechanical additions and south side of 1955 addition, facing northwest. - Albrook Air Force Station, Dispensary, East side of Canfield Avenue, Balboa, Former Panama Canal Zone, CZ

  7. Insights into PEMFC Performance Degradation from HCl in Air

    SciTech Connect

    O Baturina; A Epshteyn; P Northrup; K Swider-Lyons

    2011-12-31

    The performance degradation of a proton exchange membrane fuel cell (PEMFC) is studied in the presence of HCl in the air stream. The cathode employing carbon-supported platinum nanoparticles (Pt/C) was exposed to 4 ppm HCl in air while the cell voltage was held at 0.6 V. The HCl poisoning results in generation of chloride and chloroplatinate ions on the surface of Pt/C catalyst as determined by a combination of electrochemical tests and ex-situ chlorine K-edge X-Ray absorption near-edge structure (XANES) spectroscopy. The chloride ions inhibit the oxygen reduction reaction (ORR) and likely affect the wetting properties of diffusion media/catalyst layer, while the chloroplatinate ions are responsible for enhanced platinum particle growth most likely due to platinum dissolution-redeposition. The chloride ions can cause corrosion of the Pt nanoparticles in the presence of aqueous HCl in air even if no potential is applied. Although the majority of chloride ions are desorbed from the Pt surface by hydrogen treatment of the cathode, they partially remain in the system and re-adsorb on platinum at cell voltages of 0.5-0.9 V. Chloride ions are removed from the system and fuel cell performance at 0.5-0.7 V is restored by multiple exposures to low potentials.

  8. Stable operation of air-blowing direct methanol fuel cells with high performance

    NASA Astrophysics Data System (ADS)

    Park, Jun-Young; Lee, Jin-Hwa; Kim, Jirae; Han, Sangil; Song, Inseob

    A membrane electrode assembly (MEA) that is a combination of a catalyst-coated membrane (CCM) for the anode and a catalyst-coated substrate (CCS) for the cathode is studied under air-blower conditions for direct methanol fuel cells (DMFCs). Compared with MEAs prepared by only the CCS method, the performance of DMFC MEAs employing the combination method is significantly improved by 30% with less methanol crossover. This feature can be attributed to an enhanced electrode|membrane interface in the anode side and significantly higher catalyst efficiency. Furthermore, DMFC MEAs designed by the combination method retain high power density without any degradation, while the CCM-type cell shows a downward tendency in electrochemical performance under air-blower conditions. This may be due to MEAs with CCM have a much more difficult structure of catalytic active sites in the cathode to eliminate the water produced by electrochemical reaction. In addition, DMFCs produced via combination methods exhibit a lower water crossover flux than CCS alternatives, due to the comparatively dense structure of the CCM anode. Hence, DMFCs with a combination MEA structure demonstrate the feasibility of a small fuel cell system employing the low noise of a fan, instead of a noisy and large capacity air pump, for portable electronic devices.

  9. Performance evaluation of the latest fully automated hematology analyzers in a large, commercial laboratory setting: a 4-way, side-by-side study.

    PubMed

    Bourner, G; Dhaliwal, J; Sumner, J

    2005-01-01

    Gamma-Dynacare is a Canadian-based community laboratory partnership formed in the mid-1990s through the merger of 3 prominent Ontario medical diagnostic laboratories. Laboratory Corporation of America acquired an interest in the GD partnership in mid 2002. We service more than 10,000 community-based Canadian clinicians, hospital partners, and private clients with an integrated customer-focused system that includes specimen collection, transportation, and results reporting services. With more than 1,700 highly qualified medical, technical, and support staff and a network of laboratories, Gamma Dynacare aims to be at the forefront of technological innovation to better service the clinician base and ultimately deliver better patient care. We were looking for a hematology analyzer that would allow. (1) standardization throughout Ontario in our 4 largest sites and (2) better performance to effectively handle aged samples and minimize slide review. To select the best, most productive hematology analyzer for our environment, it was decided to perform a side-by-side comparison of the top hematology analyzers from Abbott (Cell-Dyn 3500), Beckman Coulter (LH 750), Bayer (Advia 120), and Sysmex (XE 2100), utilizing the same samples. CBC, differential and reticulocyte parameters were all evaluated according to CLSI (formerly NCCLS) and established hematology analyzer evaluation guidelines. We assessed each analyzer for precision, linearity, carryover, stability, differential capabilities, slide review rates, and throughput (clean bench studies). Two hundred samples were assessed for differential and morphology flagging on each analyzer using the reference 400 cell manual differential for comparison. Throughput was assessed by analyzing 700 consecutive samples representative of our workload mix. Stability studies at 24 hours showed that the Beckman Coulter LH 750 was least affected by EDTA, effect with minimal changes in the mean corpuscular volume (MCV) and hematocrit. Both

  10. Use of exhaust gas as sweep flow to enhance air separation membrane performance

    DOEpatents

    Dutart, Charles H.; Choi, Cathy Y.

    2003-01-01

    An intake air separation system for an internal combustion engine is provided with purge gas or sweep flow on the permeate side of separation membranes in the air separation device. Exhaust gas from the engine is used as a purge gas flow, to increase oxygen flux in the separation device without increasing the nitrogen flux.

  11. Combustion performance evaluation of air staging of palm oil blends.

    PubMed

    Mohd Jaafar, Mohammad Nazri; Eldrainy, Yehia A; Mat Ali, Muhammad Faiser; Wan Omar, W Z; Mohd Hizam, Mohd Faizi Arif

    2012-02-21

    The problems of global warming and the unstable price of petroleum oils have led to a race to develop environmentally friendly biofuels, such as palm oil or ethanol derived from corn and sugar cane. Biofuels are a potential replacement for fossil fuel, since they are renewable and environmentally friendly. This paper evaluates the combustion performance and emission characteristics of Refined, Bleached, and Deodorized Palm Oil (RBDPO)/diesel blends B5, B10, B15, B20, and B25 by volume, using an industrial oil burner with and without secondary air. Wall temperature profiles along the combustion chamber axis were measured using a series of thermocouples fitted axially on the combustion chamber wall, and emissions released were measured using a gas analyzer. The results show that RBDPO blend B25 produced the maximum emission reduction of 56.9% of CO, 74.7% of NOx, 68.5% of SO(2), and 77.5% of UHC compared to petroleum diesel, while air staging (secondary air) in most cases reduces the emissions further. However, increasing concentrations of RBDPO in the blends also reduced the energy released from the combustion. The maximum wall temperature reduction was 62.7% for B25 at the exit of the combustion chamber.

  12. Metal-air cell with performance enhancing additive

    DOEpatents

    Friesen, Cody A; Buttry, Daniel

    2015-11-10

    Systems and methods drawn to an electrochemical cell comprising a low temperature ionic liquid comprising positive ions and negative ions and a performance enhancing additive added to the low temperature ionic liquid. The additive dissolves in the ionic liquid to form cations, which are coordinated with one or more negative ions forming ion complexes. The electrochemical cell also includes an air electrode configured to absorb and reduce oxygen. The ion complexes improve oxygen reduction thermodynamics and/or kinetics relative to the ionic liquid without the additive.

  13. Fatigue and associated performance decrements in air transport operations

    NASA Technical Reports Server (NTRS)

    Lyman, E. G.; Orlady, H. W.

    1981-01-01

    A study of safety reports was conducted to examine the hypothesis that fatigue and associated performance decrements occur in air transport operations, and that these are associated with some combination of factors: circadian desynchronosis, duty time; pre-duty activity; sleep; work scheduling; workload; and environmental deprivation. The findings are based on a selected sample of reported incidents in which the reporter associated fatigue with the occurrence. In comparing the fatigue reports with a control set, significant performance decrements were found to exist related to time-of-day, awareness and attention to duty, less significantly, final phases of flights. The majority of the fatigue incidents involved such unsafe events as altitude deviations, takeoffs and landing without clearance, and the like. Considerations of duty and sleep are the major factors in the reported fatigue conditions.

  14. Simulator study of the effect of visual-motion time delays on pilot tracking performance with an audio side task

    NASA Technical Reports Server (NTRS)

    Riley, D. R.; Miller, G. K., Jr.

    1978-01-01

    The effect of time delay was determined in the visual and motion cues in a flight simulator on pilot performance in tracking a target aircraft that was oscillating sinusoidally in altitude only. An audio side task was used to assure the subject was fully occupied at all times. The results indicate that, within the test grid employed, about the same acceptable time delay (250 msec) was obtained for a single aircraft (fighter type) by each of two subjects for both fixed-base and motion-base conditions. Acceptable time delay is defined as the largest amount of delay that can be inserted simultaneously into the visual and motion cues before performance degradation occurs. A statistical analysis of the data was made to establish this value of time delay. Audio side task provided quantitative data that documented the subject's work level.

  15. Proprioceptive performance of bilateral upper and lower limb joints: side-general and site-specific effects.

    PubMed

    Han, Jia; Anson, Judith; Waddington, Gordon; Adams, Roger

    2013-05-01

    Superiority of the left upper limb in proprioception tasks performed by right-handed individuals has been attributed to better utilization of proprioceptive information by a non-preferred arm/hemisphere system. However, it is undetermined whether this holds for multiple upper and lower limb joints. Accordingly, the present study tested active movement proprioception at four pairs of upper and lower limb joints, after selecting twelve participants with both strong right arm and right leg preference. A battery of versions of the active movement extent discrimination apparatus were employed to generate the stimuli for movements of different extents at the ankle, knee, shoulder and fingers on the right and left sides of the body, and discrimination scores were derived from participants' responses. Proprioceptive performance on the non-preferred left side was significantly better than the preferred right side at all four joints tested (overall F 1, 11 = 36.36, p < 0.001, partial η (2) = 0.77). In the 8 × 8 matrix formed by all joints, only correlations between the proprioceptive accuracy scores for the right and left sides at the same joint were significant (ankles 0.93, knees 0.89, shoulders 0.87, fingers 0.91, p ≤ 0.001; all others r ≤ 0.40, p ≥ 0.20). The results point to both a side-general effect and a site-specific effect in the integration of proprioceptive information during active movement tasks, whereby the non-preferred limb/hemisphere system is specialized in the utilization of the best proprioceptive sources available at each specific joint, but the combination of sources employed differs between body sites.

  16. Do Motor Imagery Performances Depend on the Side of the Lesion at the Acute Stage of Stroke?

    PubMed Central

    Kemlin, Claire; Moulton, Eric; Samson, Yves; Rosso, Charlotte

    2016-01-01

    Motor imagery has been considered a substitute for overt motor execution to study post-stroke motor recovery. However, motor imagery abilities at the acute stage (<3 weeks) are poorly known. The aim of this study was to compare explicit and implicit motor imagery abilities in stroke patients and healthy subjects, correlate them with motor function, and investigate the role of right or left hemisphere lesions on performance. Twenty-four stroke patients at the acute stage and 24 age- and gender-matched healthy volunteers performed implicit (Hand Laterality Judgment Task) and explicit (number of imagined/executed hand movements) motor imagery tasks and a clinical motor assessment. Differences between healthy subjects and patients as well as the impact of lesion side on motor imagery were studied using ANOVA. We analyzed the relationship between motor executed and imagined movements (temporal congruence) using Pearson correlations. Our study shows that for implicit imagery, stroke patients had slower reaction times [RTs, t(46) = 1.7, p = 0.02] and higher error rates for the affected hand [t(46) = 3.7, p < 0.01] yet shared similar characteristics [angle effect: F(1,46) = 30.8, p ≤ 0.0001] with respect to healthy subjects. For the unaffected hand, right-sided stroke patients had a higher error rate and similar RTs whereas left sided stroke had higher RTs but similar error rate than healthy subjects. For explicit imagery, patients exhibited bilateral deficits compared to healthy subjects in the executed and imagined condition (p < 0.0001). Patients and healthy subjects exhibited a temporal congruence between executed and imagined movements (p ≤ 0.04) except for right-sided strokes who had no correlation for both hands. When using motor imagery as a tool for upper limb rehabilitation early after stroke, caution must be taken related to the side of the lesion. PMID:27445761

  17. Shoe collar height effect on athletic performance, ankle joint kinematics and kinetics during unanticipated maximum-effort side-cutting performance.

    PubMed

    Lam, Gilbert Wing Kai; Park, Eun Jung; Lee, Ki-Kwang; Cheung, Jason Tak-Man

    2015-01-01

    Side-step cutting manoeuvres comprise the coordination between planting and non-planting legs. Increased shoe collar height is expected to influence ankle biomechanics of both legs and possibly respective cutting performance. This study examined the shoe collar height effect on kinematics and kinetics of planting and non-planting legs during an unanticipated side-step cutting. Fifteen university basketball players performed maximum-effort side-step cutting to the left 45° direction or a straight ahead run in response to a random light signal. Seven successful cutting trials were collected for each condition. Athletic performance, ground reaction force, ankle kinematics and kinetics of both legs were analysed using paired t-tests. Results indicated that high-collar shoes resulted in less ankle inversion and external rotation during initial contact for the planting leg. The high-collar shoes also exhibited a smaller ankle range of motion in the sagittal and transverse planes for both legs, respectively. However, no collar effect was found for ankle moments and performance indicators including cutting performance time, ground contact time, propulsion ground reaction forces and impulses. These findings indicated that high-collar shoes altered ankle positioning and restricted ankle joint freedom movements in both legs, while no negative effect was found for athletic cutting performance.

  18. Air pollution, athletic health and performance at the Olympic Games.

    PubMed

    Fitch, Ken

    2016-01-01

    The objective of this study was to briefly review air pollution and its effects on athletes' health and performance and to examine air quality (AQ) at specific Olympic Summer Games between 1964 and 2008. It will focus on any attempts made by the cities hosting these Olympics to improve AQ for the Games and if undertaken, how successful these were. The author had a medical role at five of the seven Olympic Games that will be examined and hence has personal experiences. Information was obtained from the readily accessible official reports of the Olympic Games, relevant published papers and books and the internet. For each of these seven Olympic Games, monitoring AQ was far below current acceptable standards and for the majority, minimal or no data on major pollutants was available. From what can be ascertained, at these Games, AQ varied but was less than optimal in most if not all. Nevertheless, there were few reported or known unfavorable effects on the health of Olympic athletes. To date, there have been few reported consequences of sub-optimal AQ at Olympic Games. The focus on AQ at Olympic Games has gradually increased over the past five decades and is expected to continue into the future.

  19. An improved high-performance lithium-air battery.

    PubMed

    Jung, Hun-Gi; Hassoun, Jusef; Park, Jin-Bum; Sun, Yang-Kook; Scrosati, Bruno

    2012-06-10

    Although dominating the consumer electronics markets as the power source of choice for popular portable devices, the common lithium battery is not yet suited for use in sustainable electrified road transport. The development of advanced, higher-energy lithium batteries is essential in the rapid establishment of the electric car market. Owing to its exceptionally high energy potentiality, the lithium-air battery is a very appealing candidate for fulfilling this role. However, the performance of such batteries has been limited to only a few charge-discharge cycles with low rate capability. Here, by choosing a suitable stable electrolyte and appropriate cell design, we demonstrate a lithium-air battery capable of operating over many cycles with capacity and rate values as high as 5,000 mAh g(carbon)(-1) and 3 A g(carbon)(-1), respectively. For this battery we estimate an energy density value that is much higher than those offered by the currently available lithium-ion battery technology.

  20. An improved high-performance lithium-air battery

    NASA Astrophysics Data System (ADS)

    Jung, Hun-Gi; Hassoun, Jusef; Park, Jin-Bum; Sun, Yang-Kook; Scrosati, Bruno

    2012-07-01

    Although dominating the consumer electronics markets as the power source of choice for popular portable devices, the common lithium battery is not yet suited for use in sustainable electrified road transport. The development of advanced, higher-energy lithium batteries is essential in the rapid establishment of the electric car market. Owing to its exceptionally high energy potentiality, the lithium-air battery is a very appealing candidate for fulfilling this role. However, the performance of such batteries has been limited to only a few charge-discharge cycles with low rate capability. Here, by choosing a suitable stable electrolyte and appropriate cell design, we demonstrate a lithium-air battery capable of operating over many cycles with capacity and rate values as high as 5,000 mAh gcarbon-1 and 3 A gcarbon-1, respectively. For this battery we estimate an energy density value that is much higher than those offered by the currently available lithium-ion battery technology.

  1. Two-dimensional simulation of the single-sided air-coupled ultrasonic pitch-catch technique for non-destructive testing.

    PubMed

    Delrue, Steven; Van Den Abeele, Koen; Blomme, Erik; Deveugele, Jurgen; Lust, Pieter; Matar, Olivier Bou

    2010-02-01

    Non-contact air-coupled ultrasonic inspection of materials using single-sided access offers interesting possibilities for the development of in-line non-destructive testing (NDT) systems. This contribution reports observations and simulations obtained from a single-sided air-coupled pitch-catch configuration. The pitch-catch technique involves a set-up in which transmitter and receiver are located at the same side of the test object. Sound waves, reflected once or multiple times from the back-wall of the object or refracted by a discontinuity, are recorded and analyzed for visualization. The feasibility of the technique is demonstrated, experimentally, in the case of artificial defects in aluminium samples. Depending on the configuration one or more ultrasonic images of the defect can be observed, their number and relative position containing information about the location of the defect. The experiments are simulated using two distinctive methods. The first simulation is based on a ray tracing (shadow) approach, the second method uses a spectral solution implemented within COMSOL. Both simulation methods allow simple prediction of the response images in experimental conditions with supplementary levels of complexity, which will assist the development and optimization of online inspection techniques.

  2. High performance target measurement flights from Vandenberg Air Force Base

    NASA Astrophysics Data System (ADS)

    Chalfant, C. P.; Rosen, H.; Jerger, J. H.

    A description is presented of a new launch facility which is being prepared for the High Performance Target Measurement (HPTEM) booster at Vandenberg Air Force Base (VAFB). A deactivated Atlas launch complex is currently being modified to allow the rocket to be launched from a semisilo. The underground launch operations building will contain a new control center and instrumentation room. Attention is given to the Multi-Spectral Measurement Program (MSMP), details concerning the launch facility, and a target and flight safety trajectory analysis. Construction and modification of the facility is scheduled to be completed in mid-1983. The first HPTEM launch is planned to occur in April 1984. The HPTEM launch facility can also be utilized to launch Aries I (single stage) and Aries II (two-stage) probes with minor modification.

  3. A Performance Map for Ideal Air Breathing Pulse Detonation Engines

    NASA Technical Reports Server (NTRS)

    Paxson, Daniel E.

    2001-01-01

    The performance of an ideal, air breathing Pulse Detonation Engine is described in a manner that is useful for application studies (e.g., as a stand-alone, propulsion system, in combined cycles, or in hybrid turbomachinery cycles). It is shown that the Pulse Detonation Engine may be characterized by an averaged total pressure ratio, which is a unique function of the inlet temperature, the fraction of the inlet flow containing a reacting mixture, and the stoichiometry of the mixture. The inlet temperature and stoichiometry (equivalence ratio) may in turn be combined to form a nondimensional heat addition parameter. For each value of this parameter, the average total enthalpy ratio and total pressure ratio across the device are functions of only the reactant fill fraction. Performance over the entire operating envelope can thus be presented on a single plot of total pressure ratio versus total enthalpy ratio for families of the heat addition parameter. Total pressure ratios are derived from thrust calculations obtained from an experimentally validated, reactive Euler code capable of computing complete Pulse Detonation Engine limit cycles. Results are presented which demonstrate the utility of the described method for assessing performance of the Pulse Detonation Engine in several potential applications. Limitations and assumptions of the analysis are discussed. Details of the particular detonative cycle used for the computations are described.

  4. The dark and bright sides of self-efficacy in predicting learning, innovative and risky performances.

    PubMed

    Salanova, Marisa; Lorente, Laura; Martínez, Isabel M

    2012-11-01

    The objective of this study is to analyze the different role that efficacy beliefs play in the prediction of learning, innovative and risky performances. We hypothesize that high levels of efficacy beliefs in learning and innovative performances have positive consequences (i.e., better academic and innovative performance, respectively), whereas in risky performances they have negative consequences (i.e., less safety performance). To achieve this objective, three studies were conducted, 1) a two-wave longitudinal field study among 527 undergraduate students (learning setting), 2) a three-wave longitudinal lab study among 165 participants performing innovative group tasks (innovative setting), and 3) a field study among 228 construction workers (risky setting). As expected, high levels of efficacy beliefs have positive or negative consequences on performance depending on the specific settings. Unexpectedly, however, we found no time x self-efficacy interaction effect over time in learning and innovative settings. Theoretical and practical implications within the social cognitive theory of A. Bandura framework are discussed.

  5. Rotary ultrasonic elliptical machining for side milling of CFRP: tool performance and surface integrity.

    PubMed

    Geng, Daxi; Zhang, Deyuan; Xu, Yonggang; He, Fengtao; Liu, Dapeng; Duan, Zuoheng

    2015-05-01

    The rotary ultrasonic elliptical machining (RUEM) has been recognized as a new effective process to machining circular holes on CFRP materials. In CFRP face machining, the application of grinding tools is restricted for the tool clogging and the machined surface integrity. In this paper, we proposed a novel approach to extend the RUEM process to side milling of CFRP for the first time, which kept the effect of elliptical vibration in RUEM. The experiment apparatus was developed, and the preliminary experiments were designed and conducted, with comparison to conventional grinding (CG). The experimental results showed that when the elliptical vibration was applied in RUEM, a superior cutting process can be obtained compared with that in CG, including providing reduced cutting forces (2-43% decrement), an extended tool life (1.98 times), and improved surface integrity due to the intermittent material removal mechanism and the excellent chip removal conditions achieved in RUEM. It was concluded that the RUEM process is suitable to mill flat surface on CFRP composites.

  6. Air

    MedlinePlus

    ... do to protect yourself from dirty air . Indoor air pollution and outdoor air pollution Air can be polluted indoors and it can ... this chart to see what things cause indoor air pollution and what things cause outdoor air pollution! Indoor ...

  7. Regulatory Considerations of Lower Cost Air Pollution Sensor Data Performance

    EPA Science Inventory

    Low-cost, portable air quality sensors could be the next generation of air monitoring, however, this nascent technology is not without risk. This article looks at how the U.S. Environmental Protection Agency (EPA) uses air monitoring data, the procedures followed to ensure and a...

  8. Performance of Simple Gas Foil Thrust Bearings in Air

    NASA Technical Reports Server (NTRS)

    Bruckner, Robert J.

    2012-01-01

    Foil bearings are self-acting hydrodynamics devices used to support high speed rotating machinery. The advantages that they offer to process fluid lubricated machines include: high rotational speed capability, no auxiliary lubrication system, non-contacting high speed operation, and improved damping as compared to rigid hydrodynamic bearings. NASA has had a sporadic research program in this technology for almost 6 decades. Advances in the technology and understanding of foil journal bearings have enabled several new commercial products in recent years. These products include oil-free turbochargers for both heavy trucks and automobiles, high speed electric motors, microturbines for distributed power generation, and turbojet engines. However, the foil thrust bearing has not received a complimentary level of research and therefore has become the weak link of oil-free turbomachinery. In an effort to both provide machine designers with basic performance parameters and to elucidate the underlying physics of foil thrust bearings, NASA Glenn Research Center has completed an effort to experimentally measure the performance of simple gas foil thrust bearing in air. The database includes simple bump foil supported thrust bearings with full geometry and manufacturing techniques available to the user. Test conditions consist of air at ambient pressure and temperatures up to 500 C and rotational speeds to 55,000 rpm. A complete set of axial load, frictional torque, and rotational speed is presented for two different compliant sub-structures and inter-pad gaps. Data obtained from commercially available foil thrust bearings both with and without active cooling is presented for comparison. A significant observation made possible by this data set is the speed-load capacity characteristic of foil thrust bearings. Whereas for the foil journal bearing the load capacity increases linearly with rotational speed, the foil thrust bearing operates in the hydrodynamic high speed limit. In

  9. The prediction of transducer element performance from in air measurements

    NASA Astrophysics Data System (ADS)

    Schafer, M. E.

    1982-01-01

    A technique has been developed which accurately predicts the performance of underwater acoustic arrays prior to array construction. The technique is based upon the measurement of lumped-parameter equivalent circuit values for each element in the array, and is accurate in predicting the array transmit, receive and beam pattern response. The measurement procedure determines the shunt electrical and motional circuit elements from electrical imittance measurements. The electromechanical transformation ratio is derived from in-air measurements of the radiating face velocity and the input current to the transducer at resonance. The equivalent circuit values of a group of Tonpilz-type transducers were measured, and the self and mutual interaction acoustic loadings for a specific array geometry were calculated. The response of the elements was then predicted for water-loaded array conditions. Based on the predictions, a selection scheme was developed which minimized the effects of inter-element variability on array performance. The measured transmitting, receiving and beam pattern characteristics of a test array, built using the selected elements, were compared to predictions made before the array was built. The results indicated that the technique is accurate over a wide frequency range.

  10. Enhancing the decoding performance of optical wireless communication systems using receiver-side predistortion.

    PubMed

    Wang, Qi; Wang, Zhaocheng; Chen, Sheng; Hanzo, Lajos

    2013-12-16

    White light emitting diodes (LEDs) have been widely utilized for illumination owing to their desired properties of inherent bright output, high efficiency, low power consumption and long life-time. They are also increasingly applied in optical wireless communications for realizing high data rate transmission. This paper presents an improved scheme relying on the insertion of a simple predistortion module before the decoder at the receiver of optical wireless communication systems that use white LEDs. The proposed predistortion scheme exploits the inherent nature of mixing the three unequal optical-power primary colours in generating white light to enhance the system's performance. Specifically, we design this predistortion module by minimizing the upper bound of the error probability in conjunction with a soft-decision decoder. Our simulation results demonstrate that the detection performance is considerably improved with the aid of the proposed predistortion module.

  11. Cardiac reactivity and preserved performance under stress: two sides of the same coin?

    PubMed

    Pattyn, Nathalie; Mairesse, Olivier; Cortoos, Aisha; Morais, José; Soetens, Eric; Roelands, Bart; van den Nest, Annick; Kolinsky, Régine

    2014-07-01

    In the present experiment, cognitive control under stress was investigated using a real-life paradigm, namely an evaluation flight for military student pilots. The magnitude of cognitive interference on color-word, numerical and emotional Stroop paradigms was studied during a baseline recording and right before the test flight. Cardio-respiratory parameters were simultaneously assessed during rest and the performance of the Stroop tasks. Cognitive data suggested a different speed/accuracy trade-off under stress, and no modulation of the interference effect for color words or numerical stimuli. However, we observed a major increase in error rates for specific emotional stimuli related to the evaluation situation in the stress condition. The increase in cognitive interference from emotional stimuli, expressed as an increase in error rates, was correlated to the decreased cardiac reactivity to challenge in the stress situation. This relationship is discussed in the framework of Sanders' (1983) model of stress and performance. In terms of future research, this link warrants a fruitful lead to be followed for investigating the causal mechanism of performance decrements under the influence of stress.

  12. Effect of Small-Sided Games and Repeated Shuffle Sprint Training on Physical Performance in Elite Handball Players.

    PubMed

    Dello Iacono, Antonio; Ardigò, Luca P; Meckel, Yoav; Padulo, Johnny

    2016-03-01

    This study was designed to compare the effects of small-sided games (SSGs) and repeated shuffle sprint (RSS) training on repeated sprint ability (RSA) and countermovement jump (CMJ) tests performances of elite handball players. Eighteen highly trained players (24.8 ± 4.4 years) were assigned to either SSG or RSS group training protocols twice a week for 8 weeks. The SSG training consisted of 5 small-sided handball games with 3-a-side teams excluding goalkeepers. The RSS consisted of 2 sets of 14-17 of 20-m shuttle sprints and 9-m jump shots interspersed by 20-second recoveries. Before and after training, the following performance variables were assessed: speed on 10-m and 20-m sprint time, agility and RSA time, CMJ height, standing throw, and jump shot speed. Significant pre-to-post treatment improvements were found in all the assessed variables following both training protocols (multivariate analysis of variance, p ≤ 0.05). There was a significantly greater improvement on 10-m sprint, CMJ, and jump shooting, after the RSS in comparison with SSG training (+4.4% vs. +2.4%, +8.6% vs. +5.6%, and +5.5% vs. +2.7%, respectively). Conversely, agility and standing throwing showed lower improvements after RSS in comparison with SSG (+1.0% vs. +7.8% and +1.6% vs. +9.0%, respectively). These results indicate that these training methods are effective for fitness development among elite adult handball players during the last period of the competitive season. Specifically, SSG seems to be more effective in improving agility and standing throw, whereas RSS seems preferable in improving 10-m sprint, CMJ, and jump shot.

  13. Robust modeling and performance analysis of high-power diode side-pumped solid-state laser systems.

    PubMed

    Kashef, Tamer; Ghoniemy, Samy; Mokhtar, Ayman

    2015-12-20

    In this paper, we present an enhanced high-power extrinsic diode side-pumped solid-state laser (DPSSL) model to accurately predict the dynamic operations and pump distribution under different practical conditions. We introduce a new implementation technique for the proposed model that provides a compelling incentive for the performance assessment and enhancement of high-power diode side-pumped Nd:YAG lasers using cooperative agents and by relying on the MATLAB, GLAD, and Zemax ray tracing software packages. A large-signal laser model that includes thermal effects and a modified laser gain formulation and incorporates the geometrical pump distribution for three radially arranged arrays of laser diodes is presented. The design of a customized prototype diode side-pumped high-power laser head fabricated for the purpose of testing is discussed. A detailed comparative experimental and simulation study of the dynamic operation and the beam characteristics that are used to verify the accuracy of the proposed model for analyzing the performance of high-power DPSSLs under different conditions are discussed. The simulated and measured results of power, pump distribution, beam shape, and slope efficiency are shown under different conditions and for a specific case, where the targeted output power is 140 W, while the input pumping power is 400 W. The 95% output coupler reflectivity showed good agreement with the slope efficiency, which is approximately 35%; this assures the robustness of the proposed model to accurately predict the design parameters of practical, high-power DPSSLs.

  14. Understanding Moisture and Carbon Dioxide Involved Interfacial Reactions on Electrochemical Performance of Lithium-Air Batteries Catalyzed by Gold/Manganese-Dioxide.

    PubMed

    Wang, Guoqing; Huang, Liliang; Liu, Shuangyu; Xie, Jian; Zhang, Shichao; Zhu, Peiyi; Cao, Gaoshao; Zhao, Xinbing

    2015-11-04

    Lithium-air (Li-air) battery works essentially based on the interfacial reaction of 2Li + O2 ↔ Li2O2 on the catalyst/oxygen-gas/electrolyte triphase interface. Operation of Li-air batteries in ambient air still remains a great challenge despite the recent development, because some side reactions related to moisture (H2O) and carbon dioxide (CO2) will occur on the interface with the formation of some inert byproducts on the surface of the catalyst. In this work, we investigated the effect of H2O and CO2 on the electrochemical performance of Li-air batteries to evaluate the practical operation of the batteries in ambient air. The use of a highly efficient gold/δ-manganese-dioxide (Au/δ-MnO2) catalyst helps to understand the intrinsic mechanism of the effect. We found that H2O has a more detrimental influence than CO2 on the battery performance when operated in ambient air. The battery operated in simulated dry air can sustain a stable cycling up to 200 cycles at 400 mA g(-1) with a relatively low polarization, which is comparable with that operated in pure O2. This work provides a possible method to operate Li-air batteries in ambient air by using optimized catalytic electrodes with a protective layer, for example a hydrophobic membrane.

  15. Temporal Changes in Technical and Physical Performances During a Small-Sided Game in Elite Youth Soccer Players

    PubMed Central

    Moreira, Alexandre; Saldanha Aoki, Marcelo; Carling, Chris; Alan Rodrigues Lopes, Rafael; Felipe Schultz de Arruda, Ademir; Lima, Marcelo; Cesar Correa, Umberto; Bradley, Paul S

    2016-01-01

    Background There have been claims that small-sided games (SSG) may generate an appropriate environment to develop youth players’ technical performance associated to game-related problem solving. However, the temporal change in technical performance parameters of youth players during SSG is still unknown. Objectives The aim of this study was to examine temporal changes in technical and physical performances during a small-sided game (SSG) in elite soccer players. Methods Sixty elite youth players (age 14.8 ± 0.2 yr; stature 177 ± 5 cm; body mass 66.2 ± 4.7 kg) completed a 5 v 5 SSG using two repetitions of 8 minutes interspersed by 3 minutes of passive recovery. To evaluate temporal changes in performance, the data were analysed across 4 minutes quarters. Physical performance parameters included the total distance covered (TDC), the frequency of sprints (>18 km•h-1), accelerations and decelerations (> 2.0 m•s-2 and - 2.0 m•s-2), metabolic power (W•kg-1), training impulse (TRIMP), TDC: TRIMP, number of impacts, and body load. Technical performance parameters included goal attempts, total number of tackles, tackles and interceptions, total number of passes, and passes effectiveness. Results All physical performance parameters decreased from the first to the last quarter with notable declines in TDC, metabolic power and the frequency of sprints, accelerations and decelerations (P < 0.05; moderate to very large ES: 1.08 - 3.30). However, technical performance parameters did not vary across quarters (P > 0.05; trivial ES for 1st v 4th quarters: 0.15 - 0.33). Conclusions The data demonstrate that technical performance is maintained despite substantial declines in physical performance during a SSG in elite youth players. This finding may have implications for designing SSG’s for elite youth players to ensure physical, technical and tactical capabilities are optimized. Modifications in player number, pitch dimensions, rules, coach encouragement, for instance

  16. Into rude air: hummingbird flight performance in variable aerial environments.

    PubMed

    Ortega-Jimenez, V M; Badger, M; Wang, H; Dudley, R

    2016-09-26

    Hummingbirds are well known for their ability to sustain hovering flight, but many other remarkable features of manoeuvrability characterize the more than 330 species of trochilid. Most research on hummingbird flight has been focused on either forward flight or hovering in otherwise non-perturbed air. In nature, however, hummingbirds fly through and must compensate for substantial environmental perturbation, including heavy rain, unpredictable updraughts and turbulent eddies. Here, we review recent studies on hummingbirds flying within challenging aerial environments, and discuss both the direct and indirect effects of unsteady environmental flows such as rain and von Kármán vortex streets. Both perturbation intensity and the spatio-temporal scale of disturbance (expressed with respect to characteristic body size) will influence mechanical responses of volant taxa. Most features of hummingbird manoeuvrability remain undescribed, as do evolutionary patterns of flight-related adaptation within the lineage. Trochilid flight performance under natural conditions far exceeds that of microair vehicles at similar scales, and the group as a whole presents many research opportunities for understanding aerial manoeuvrability.This article is part of the themed issue 'Moving in a moving medium: new perspectives on flight'.

  17. Performance of Spherically Focused Air-Coupled Ultrasonic Transducers

    NASA Astrophysics Data System (ADS)

    Chimenti, D. E.; Song, Junho

    2007-03-01

    This paper reports the development, testing, and performance evaluation of spherically focused capacitive air-coupled ultrasonic transducers 1 and 5 cm in diameter. A flexible micro-machined copper/polyimide backplate permits a conformal fit to a spherically shaped fixture, forming the rear capacitor plate. A spherically deformed 6-μm aluminized Mylar foil forms the front capacitor plate, completing the transducer. The device's frequency spectrum is centered near 800 kHz with -6dB points at about 400 and 1200 kHz. The device's focal-plane behavior is successfully modeled theoretically as a focused piston radiator. The imaging and defect detection capabilities of the new transducer are demonstrated in a series of critical tests: a 250-μm wire is easily imaged in a confocal geometry with a second device. Composite, honeycomb, and wood samples are imaged in through-transmission C-scans, showing internal defects. A printed circuit board is imaged, showing features as small as 200-μm.

  18. Air humidity and water pressure effects on the performance of air-cathode microbial fuel cell cathodes

    NASA Astrophysics Data System (ADS)

    Ahn, Yongtae; Zhang, Fang; Logan, Bruce E.

    2014-02-01

    To better understand how air cathode performance is affected by air humidification, microbial fuel cells were operated under different humidity conditions or water pressure conditions. Maximum power density decreased from 1130 ± 30 mW m-2 with dry air to 980 ± 80 mW m-2 with water-saturated air. When the cathode was exposed to higher water pressures by placing the cathode in a horizontal position, with the cathode oriented so it was on the reactor bottom, power was reduced for both with dry (1030 ± 130 mW m-2) and water-saturated (390 ± 190 mW m-2) air. Decreased performance was partly due to water flooding of the catalyst, which would hinder oxygen diffusion to the catalyst. However, drying used cathodes did not improve performance in electrochemical tests. Soaking the cathode in a weak acid solution, but not deionized water, mostly restored performance (960 ± 60 mW m-2), suggesting that there was salt precipitation in the cathode that was enhanced by higher relative humidity or water pressure. These results showed that cathode performance could be adversely affected by both flooding and the subsequent salt precipitation, and therefore control of air humidity and water pressure may need to be considered for long-term MFC operation.

  19. Performance studies of diode-side-pumped CW Nd:YAG laser in copper coated optical pump cavity

    NASA Astrophysics Data System (ADS)

    Sundar, R.; Ranganathan, K.; Nath, A. K.

    2007-10-01

    This paper reports the performance studies of Nd:YAG rods with different diameters and doping concentration in the CW diode-side-pumped geometry. We have used p-polarized diodes to pump the active medium and we studied the performance of different rods in terms of thermal lensing, its fluorescence profile, power output, and M2 factor of the laser beam. We achieved a maximum of 378 W of output power for an input pump power of 757 W, which corresponds to optical conversion efficiency close to 50%. The slope efficiency of the system was 56.4%. These efficiencies are the highest reported to the best of our knowledge and we achieved with ∅ 4 mm×100 mm Nd:YAG rod at 1.1-at% doping.

  20. Indoor Air Quality and Student Performance [and Case Studies].

    ERIC Educational Resources Information Center

    Environmental Protection Agency, Washington, DC. Office of Radiation and Indoor Air.

    This report examines how indoor air quality (IAQ) affects a child's ability to learn and provides several case studies of schools that have successfully addressed their indoor air problems, the lessons learned from that experience, and what long-term practices and policies emerged from the effort. The report covers the effects from…

  1. The Application of Advanced Technology to Improve Air Bag Performance

    NASA Technical Reports Server (NTRS)

    Phen, R.; Dowdy, M.; Ebbeler, D.; Kim, E.; Moore, N.; Van Zandt, T.

    1998-01-01

    In December 1996 the National Highway Traffic Safety Administration (NHTSA) and the National Aeronautics and Space Administration (NASA) signed a memorandum of understanding for NASA to assess the capability of advanced technology to reduce air bag inflation-induced injuries and increase air bag effectiveness.

  2. 77 FR 62473 - Safety Zone, Seafair Blue Angels Air Show Performance, Seattle, WA

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-15

    ... hazards associated with the Seafair Blue Angels Air Show Performance, which include low flying high speed... Performance, which include low flying high speed aircraft. C. Basis and Purpose The Coast Guard proposes to... Angels Air Show Performance, which include low flying high speed aircraft. This proposed rule...

  3. 75 FR 23589 - Safety Zone Regulations, Seafair Blue Angels Air Show Performance, Seattle, WA

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-04

    ... SECURITY Coast Guard 33 CFR Part 165 Safety Zone Regulations, Seafair Blue Angels Air Show Performance... Guard will enforce a safety zone on Lake Washington, WA for the annual Seafair Blue Angels Air Show from... establish a safety zone on the waters of Lake Washington for the annual Seafair Blue Angels Air...

  4. Air Pollution and Its Effects on an Individual's Health and Exercise Performance.

    ERIC Educational Resources Information Center

    Singh, A. I. Clifford

    1988-01-01

    Air Pollution is a common environmental stressor affecting the training and competitive performance of athletes, commonly irritating the eyes, nose, and throat. The health and exercise effects of such primary and secondary air pollutants as carbon monoxide, sulfur dioxide, air particulates, ozone, and nitrogen dioxide are discussed. (CB)

  5. Compression-ignition Engine Performance at Altitudes and at Various Air Pressures and Temperatures

    NASA Technical Reports Server (NTRS)

    Moore, Charles S; Collins, John H

    1937-01-01

    Engine test results are presented for simulated altitude conditions. A displaced-piston combustion chamber on a 5- by 7-inch single cylinder compression-ignition engine operating at 2,000 r.p.m. was used. Inlet air temperature equivalent to standard altitudes up to 14,000 feet were obtained. Comparison between performance at altitude of the unsupercharged compression-ignition engine compared favorably with the carburetor engine. Analysis of the results for which the inlet air temperature, inlet air pressure, and inlet and exhaust pressure were varied indicates that engine performance cannot be reliably corrected on the basis of inlet air density or weight of air charge. Engine power increases with inlet air pressure and decreases with inlet air temperatures very nearly as straight line relations over a wide range of air-fuel ratios. Correction factors are given.

  6. Side-specific effects by cadmium exposure: Apical and basolateral treatment in a coculture model of the blood-air barrier

    SciTech Connect

    Papritz, Mirko; Pohl, Christine; Wuebbeke, Christoph; Moisch, Michaela; Hofmann, Helene; Hermanns, Maria Iris; Thiermann, Horst; Kirkpatrick, Charles James; Kehe, Kai

    2010-06-15

    Cadmium (Cd{sup 2+}) is a widespread environmental pollutant, which is associated with a wide variety of cytotoxic and metabolic effects. Recent studies showed that intoxication with the heavy metal most importantly targets the integrity of the epithelial barrier. In our study, the lung epithelial cell line, NCI H441, was cultured with the endothelial cell line, ISO-HAS-1, as a bilayer on a 24-well HTS-Transwell (registered) filter plate. This coculture model was exposed to various concentrations of CdCl{sub 2}. The transepithelial electrical resistance decreased on the apical side only after treatment with high Cd{sup 2+} concentrations after 48 h. By contrast, a breakdown of TER to less than 5% of baseline could be observed much earlier (after 24 h) when Cd{sup 2+} was administered from the basal side. Observations of cell layer fragmentation and widening of intercellular spaces confirmed the barrier breakdown only for the basolaterally treated samples. Furthermore, the cytotoxicity and release of proinflammatory markers was enhanced if samples were exposed to Cd{sup 2+} from the basal side compared to treatment from the apical side. Moreover, we could demonstrate that a high concentration of Ca{sup 2+} could prevent the barrier-disrupting effect of Cd{sup 2+}. In conclusion, the exposure of Cd{sup 2+} to cocultures of lung cells caused a decrease in TER, major morphological changes, a reduction of cell viability and an increase of cytokine release, but the effects markedly differed between the two modes of exposure. Therefore, our results suggest that intact epithelial TJs may play a major role in protecting the air-blood barrier from inhaled Cd{sup 2+}.

  7. Side-chain engineering of benzodithiophene-fluorinated quinoxaline low-band-gap co-polymers for high-performance polymer solar cells.

    PubMed

    Xu, Xiaopeng; Wu, Yulei; Fang, Junfeng; Li, Zuojia; Wang, Zhenguo; Li, Ying; Peng, Qiang

    2014-10-06

    A new series of donor-acceptor co-polymers based on benzodithiophene and quinoxaline with various side chains have been developed for polymer solar cells. The effect of the degree of branching and dimensionality of the side chains were systematically investigated on the thermal stability, optical absorption, energy levels, molecular packing, and photovoltaic performance of the resulting co-polymers. The results indicated that the linear and 2D conjugated side chains improved the thermal stabilities and optical absorptions. The introduction of alkylthienyl side chains could efficiently lower the energy levels compared with the alkoxyl-substituted analogues, and the branched alkoxyl side chains could deepen the HOMO levels relative to the linear alkoxyl chains. The branched alkoxyl groups induced better lamellar-like ordering, but poorer face-to-face packing behavior. The 2D conjugated side chains had a negative influence on the crystalline properties of the co-polymers. The performance of the devices indicated that the branched alkoxyl side chains improved the Voc, but decreased the Jsc and fill factor (FF). However, the 2D conjugated side chains would increase the Voc, Jsc, and FF simultaneously. For the first time, our work provides insight into molecular design strategies through side-chain engineering to achieve efficient polymer solar cells by considering both the degree of branching and dimensionality.

  8. Performance of Air-cooled Engine Cylinders Using Blower Cooling

    NASA Technical Reports Server (NTRS)

    Schey, Oscar W; Ellerbrock, Herman H , Jr

    1936-01-01

    An investigation was made to obtain information on the minimum quantity of air and power required to cool conventional air cooled cylinders at various operating conditions when using a blower. The results of these tests show that the minimum power required for satisfactory cooling with an overall blower efficiency of 100 percent varied from 2 to 6 percent of the engine power depending on the operating conditions. The shape of the jacket had a large effect on the cylinder temperatures. Increasing the air speed over the front of the cylinder by keeping the greater part of the circumference of the cylinder covered by the jacket reduced the temperatures over the entire cylinder.

  9. Performance of PEM Liquid-Feed Direct Methanol-Air Fuel Cells

    NASA Technical Reports Server (NTRS)

    Narayanan, S. R.

    1995-01-01

    A direct methanol-air fuel cell operating at near atmospheric pressure, low-flow rate air, and at temperatures close to 60oC would tremendously enlarge the scope of potential applications. While earlier studies have reported performance with oxygen, the present study focuses on characterizing the performance of a PEM liquid feed direct methanol-air cell consisting of components developed in house. These cells employ Pt-Ru catalyst in the anode, Pt at the cathode and Nafion 117 as the PEM. The effect of pressure, flow rate of air and temperature on cell performance has been studied. With air, the performance level is as high as 0.437 V at 300 mA/cm2 (90oC, 20 psig, and excess air flow) has been attained. Even more significant is the performance level at 60oC, 1 atm and low flow rates of air (3-5 times stoichiometric), which is 0.4 V at 150 mA/cm2. Individual electrode potentials for the methanol and air electrode have been separated and analyzed. Fuel crossover rates and the impact of fuel crossover on the performance of the air electrode have also been measured. The study identifies issues specific to the methanol-air fuel cell and provides a basis for improvement strategies.

  10. Improving Compressed Air System Performance: A Sourcebook for Industry

    SciTech Connect

    2003-11-01

    NREL will produce this sourcebook for DOE's Industrial Technologies Office as part of a series of documents on industrial energy equipment. The sourcebook is a reference for industrial compressed air system users, outlining opportunities to improve system efficiency.

  11. Register Closing Effects on Forced Air Heating System Performance

    SciTech Connect

    Walker, Iain S.

    2003-11-01

    Closing registers in forced air heating systems and leaving some rooms in a house unconditioned has been suggested as a method of quickly saving energy for California consumers. This study combined laboratory measurements of the changes in duct leakage as registers are closed together with modeling techniques to estimate the changes in energy use attributed to closing registers. The results of this study showed that register closing led to increased energy use for a typical California house over a wide combination of climate, duct leakage and number of closed registers. The reduction in building thermal loads due to conditioning only a part of the house was offset by increased duct system losses; mostly due to increased duct leakage. Therefore, the register closing technique is not recommended as a viable energy saving strategy for California houses with ducts located outside conditioned space. The energy penalty associated with the register closing technique was found to be minimized if registers furthest from the air handler are closed first because this tends to only affect the pressures and air leakage for the closed off branch. Closing registers nearer the air handler tends to increase the pressures and air leakage for the whole system. Closing too many registers (more than 60%) is not recommended because the added flow resistance severely restricts the air flow though the system leading to safety concerns. For example, furnaces may operate on the high-limit switch and cooling systems may suffer from frozen coils.

  12. Thermal comfort, perceived air quality, and cognitive performance when personally controlled air movement is used by tropically acclimatized persons.

    PubMed

    Schiavon, S; Yang, B; Donner, Y; Chang, V W-C; Nazaroff, W W

    2016-10-18

    In a warm and humid climate, increasing the temperature set point offers considerable energy benefits with low first costs. Elevated air movement generated by a personally controlled fan can compensate for the negative effects caused by an increased temperature set point. Fifty-six tropically acclimatized persons in common Singaporean office attire (0.7 clo) were exposed for 90 minutes to each of five conditions: 23, 26, and 29°C and in the latter two cases with and without occupant-controlled air movement. Relative humidity was maintained at 60%. We tested thermal comfort, perceived air quality, sick building syndrome symptoms, and cognitive performance. We found that thermal comfort, perceived air quality, and sick building syndrome symptoms are equal or better at 26°C and 29°C than at the common set point of 23°C if a personally controlled fan is available for use. The best cognitive performance (as indicated by task speed) was obtained at 26°C; at 29°C, the availability of an occupant-controlled fan partially mitigated the negative effect of the elevated temperature. The typical Singaporean indoor air temperature set point of 23°C yielded the lowest cognitive performance. An elevated set point in air-conditioned buildings augmented with personally controlled fans might yield benefits for reduced energy use and improved indoor environmental quality in tropical climates.

  13. Improving Compressed Air System Performance: A Sourcebook for Industry v3

    SciTech Connect

    Ron Marshall, William Scales, Gary Shafer, Paul Shaw, Paul Sheaffer, Rick Stasyshan, H.P.

    2016-03-01

    This sourcebook is designed to provide compressed air system users with a reference that outlines opportunities for system performance improvements. It is not intended to be a comprehensive technical text on improving compressed air systems, but rather a document that makes compressed air system users aware of the performance improvement potential, details some of the significant opportunities, and directs users to additional sources of assistance.

  14. Advances in shell side boiling of refrigerants

    NASA Astrophysics Data System (ADS)

    Webb, Ralph L.

    The design of shell and tube evaporators used in air conditioning and refrigeration applications is discussed. The heat exchanger geometry of interest involves evaporation or condensation on the shell side of a horizontal tube bundle. Enhanced heat transfer geometries are typically used for shell side evaporation and for forced convection to water on the tube side. Refrigerant boiling data and forced convection refrigerant boiling correlations are described. The refrigerants of interest include R-11, 12, 22, 123, and 134a. Thermal design methods for sizing of the evaporator and condenser are outlined. A computer model for prediction of the evaporator performance is described.

  15. Performance evaluation of a selected three-ton air-to-air heat pump in the heating mode

    NASA Astrophysics Data System (ADS)

    Domingorena, A. A.; Ball, S. J.

    1980-01-01

    An air-to-air split system residential heat pump of nominal under laboratory conditions. This was the second of a planned series of experiments to obtain a data base of system and component performance for heat pumps. The system was evaluated under both steady-state and frosting-defrosting conditions; sensitivity of the system performance to variations in the refrigerant charge was measured. From the steady-state tests, the heating capacity and coefficient of performance were computed, and evaluations were made of the performance parameters of the fan and fan motor units, the heat exchangers and refrigerant metering device, and the compressor. System heat losses were analyzed. The frosting-defrosting tests allowed the observation of system and component performance under dynamic conditions, and measurement of performance degradation under frosting conditions.

  16. 16 CFR Appendix I to Part 305 - Heating Performance and Cost for Central Air Conditioners

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 16 Commercial Practices 1 2013-01-01 2013-01-01 false Heating Performance and Cost for Central Air... RULEâ) Pt. 305, App. I Appendix I to Part 305—Heating Performance and Cost for Central Air Conditioners Manufacturer's rated heating capacity (Btu's/hr.) Range of HSPF's Low High Single Package Units Heat...

  17. 16 CFR Appendix I to Part 305 - Heating Performance and Cost for Central Air Conditioners

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 16 Commercial Practices 1 2014-01-01 2014-01-01 false Heating Performance and Cost for Central Air... CONSERVATION ACT (âENERGY LABELING RULEâ) Pt. 305, App. I Appendix I to Part 305—Heating Performance and Cost for Central Air Conditioners Manufacturer's rated heating capacity (Btu's/hr.) Range of HSPF's...

  18. 16 CFR Appendix I to Part 305 - Heating Performance and Cost for Central Air Conditioners

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 16 Commercial Practices 1 2011-01-01 2011-01-01 false Heating Performance and Cost for Central Air... RULEâ) Pt. 305, App. I Appendix I to Part 305—Heating Performance and Cost for Central Air Conditioners Manufacturer's rated heating capacity (Btu's/hr.) Range of HSPF's Low High Single Package Units Heat...

  19. 16 CFR Appendix I to Part 305 - Heating Performance and Cost for Central Air Conditioners

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 16 Commercial Practices 1 2012-01-01 2012-01-01 false Heating Performance and Cost for Central Air... RULEâ) Pt. 305, App. I Appendix I to Part 305—Heating Performance and Cost for Central Air Conditioners Manufacturer's rated heating capacity (Btu's/hr.) Range of HSPF's Low High Single Package Units Heat...

  20. 16 CFR Appendix I to Part 305 - Heating Performance and Cost for Central Air Conditioners

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Heating Performance and Cost for Central Air... RULEâ) Pt. 305, App. I Appendix I to Part 305—Heating Performance and Cost for Central Air Conditioners Manufacturer's rated heating capacity (Btu's/hr.) Range of HSPF's Low High Single Package Units Heat...

  1. Effects of surface-active block copolymers with oxyethylene and fluoroalkyl side chains on the antifouling performance of silicone-based films.

    PubMed

    Martinelli, Elisa; Gunes, Deniz; Wenning, Brandon M; Ober, Christopher K; Finlay, John A; Callow, Maureen E; Callow, James A; Di Fino, Alessio; Clare, Anthony S; Galli, Giancarlo

    2016-01-01

    Block copolymers made from a poly(dimethyl siloxane) (Si) and a poly(meth)acrylate carrying oxyethylene (EG) or fluoroalkyl (AF) side chains were synthesized and incorporated as surface-active components into a silicone matrix to produce cross-linked films with different surface hydrophilicity/phobicity. Near-edge X-ray absorption fine structure (NEXAFS) studies showed that film surfaces containing Si-EG were largely populated by the siloxane, with the oxyethylene chains present only to a minor extent. In contrast, the fluorinated block was selectively segregated to the polymer-air interface in films containing Si-AF as probed by NEXAFS and X-ray photoelectron spectroscopy (XPS) analyses. Such differences in surface composition were reflected in the biological performance of the coatings. While the films with Si-EG showed a higher removal of both Ulva linza sporelings and Balanus amphitrite juveniles than the silicone control, those with Si-AF exhibited excellent antifouling properties, preventing the settlement of cyprids of B. amphitrite.

  2. Air Sensor Kit Performance Testing and Pollutant Mapping Supports Community Air Monitoring Project

    EPA Pesticide Factsheets

    EPA is collaborating on a research project with the South Coast Air Quality Management District in Diamond Bar, Calif. to gain an enhanced understanding of fine particulate matter (PM2.5) and ozone concentrations across the study area.

  3. [Studies on the performance of the dental air turbine handpieces. (Part 1). Air pressure and bur length to be influenced over the rotational performance of the air bearing type handpieces (author's transl)].

    PubMed

    Miyairi, H; Muramatsu, A

    1979-07-01

    Air turbine handpieces are used as the dental cutting instruments for the clinical use and many appliances. But, there are no studies on the performance of air turbine handpieces. So, this paper shows the rotational performance of air turbine handpieces which are influenced over the supplying air pressure and cutting bur length. Experimentally used air turbine handpieces is air bearing type and it's set up air pressure to be supplied is 3.5 kg/cm2. So, in this experiments, the range of air pressure is 1.8 approximately 3.5 kg/cm2, which is established five stages. And the bur length of the rotational parts is 5 approximately 9 mm with five steps. As the results, the rotational performance of air handpieces are influenced over these factors of the air pressure and the bur length. And air pressure to be supplied are influenced to be not only over the rotational speed but the load for the putting a stop to the revolutions.

  4. The pollution removal and stormwater reduction performance of street-side bioretention basins after ten years in operation.

    PubMed

    Lucke, Terry; Nichols, Peter W B

    2015-12-01

    This study evaluated the pollution removal and hydrologic performance of five, 10-year old street-side bioretention systems. The bioretention basins were subjected to a series of simulated rainfall events using synthetic stormwater. Four different pollution concentrations were tested on three of the bioretention basins. The four concentrations tested were: A) no pollution; B) typical Australian urban pollutant loads; C) double the typical pollution loads, and; D) five times the typical pollution loads. Tests were also undertaken to determine the levels of contaminant and heavy metals build-up that occurred in the filter media over the 10 year operational life of the bioretention systems. Although highly variable, the overall hydrological performance of the basins was found to be positive, with all basins attenuating flows, reducing both peak flow rates and total outflow volumes. Total suspended solids removal performance was variable for all tests and no correlation was found between performance and dosage. Total nitrogen (TN) removal was positive for Tests B, C and D. However, the TN removal results for Test A were found to be negative. Total phosphorus (TP) was the only pollutant to be effectively removed from all basins for all four synthetic stormwater tests. The study bioretention basins were found to export pollutants during tests where no pollutants were added to the simulated inflow water (Test A). Heavy metal and hydrocarbon testing undertaken on the bioretention systems found that the pollution levels of the filter media were still within acceptable limits after 10 years in operation. This field study has shown bioretention basin pollution removal performance to be highly variable and dependant on a range of factors including inflow pollution concentrations, filter media, construction methods and environmental factors. Further research is required in order to fully understand the potential stormwater management benefits of these systems.

  5. Upgrading the performance of groudwater VOC air strippers

    SciTech Connect

    Nelson, A.D.; Schmitt, R.J.; Dickeson, D.

    1997-12-31

    Rocketdynes Santa Susana Field Laboratory has been treating groundwater to remove chlorinated solvents since 1987. Six air stripping treatment installations, using vapor-phase carbon to control air emissions, have consistently met effluent quality standards over nine years of operation. In 1995, Rocketdyne embarked on an inspection and maintenance program to thoroughly check tower equipment and packing condition and to improve treatment efficiency using new packing technology now available. Baseline removal efficiency measurements were made on one large-capacity air stripper, which was then shut down for inspection. The original random packing was found to be fouled, and had settled too far below the level of the spray nozzle. The packing was removed, and replaced with a newer, high-efficiency packing. As a result, single-stage removal efficiency for trichloroethylene increased from 98.5% to > 99.60%. Aside from demonstrating the improvement attainable by upgrading the packing media, Rocketdyne`s maintenance program also highlighted the critical importance of proper liquid distribution. At one point, the refurbished air stripper was overpacked, resulting in concentration of the water spray near the center of the packed section. The liquid distribution was found to remain grossly nonuniform even after the water had trickled down over 8.2 meters of packing in a 91-cm diameter column. 4 refs., 1 fig., 5 tabs.

  6. How DLA’s Supply Performance Affects Air Force Readiness

    DTIC Science & Technology

    1990-10-01

    used by the Air Force, Navy, and Army, as well) are described in a paper by Victor J. Presutti, Jr., and Richard C. Trepp , "More Ado About Economic...how wholesale safety-level requirements for consumables were to be computed. The basic approach of the Presutti/ Trepp method is to minimize ordering

  7. Indoor thermal performance evaluation of the SEPCO air collector

    NASA Technical Reports Server (NTRS)

    1977-01-01

    The procedures used and the results obtained during the evaluation test program on the Solaron solar air collector, model EF-212, under simulated conditions for comparison with data collected in outdoor tests on the same collector are given. The test article was a single glazed collector with a nonsensitive absorber plate, aluminum box frame, and one inch isocyanurate foam insulation.

  8. Evaluation of Advanced Air Bag Deployment Algorithm Performance using Event Data Recorders

    PubMed Central

    Gabler, Hampton C.; Hinch, John

    2008-01-01

    This paper characterizes the field performance of occupant restraint systems designed with advanced air bag features including those specified in the US Federal Motor Vehicle Safety Standard (FMVSS) No. 208 for advanced air bags, through the use of Event Data Recorders (EDRs). Although advanced restraint systems have been extensively tested in the laboratory, we are only beginning to understand the performance of these systems in the field. Because EDRs record many of the inputs to the advanced air bag control module, these devices can provide unique insights into the characteristics of field performance of air bags. The study was based on 164 advanced air bag cases extracted from NASS/CDS 2002-2006 with associated EDR data. In this dataset, advanced driver air bags were observed to deploy with a 50% probability at a longitudinal delta-V of 9 mph for the first stage, and at 26 mph for both inflator stages. In general, advanced air bag performance was as expected, however, the study identified cases of air bag deployments at delta-Vs as low as 3-4 mph, non-deployments at delta-Vs over 26 mph, and possible delayed air bag deployments. PMID:19026234

  9. The field performance of frontal air bags: a review of the literature.

    PubMed

    Kent, Richard; Viano, David C; Crandall, Jeff

    2005-03-01

    This article presents a broad review of the literature on frontal air bag field performance, starting with the initial government and industry projections of effectiveness and concluding with the most recent assessments of depowered systems. This review includes as many relevant metrics as practicable, interprets the findings, and provides references so the interested reader can further evaluate the limitations, confounders, and utility of each metric. The evaluations presented here range from the very specific (individual case studies) to the general (statistical analyses of large databases). The metrics used to evaluate air bag performance include fatality reduction or increase; serious, moderate, and minor injury reduction or increase; harm reduction or increase; and cost analyses, including insurance costs and the cost of life years saved for various air bag systems and design philosophies. The review begins with the benefits of air bags. Fatality and injury reductions attributable to the air bag are presented. Next, the negative consequences of air bag deployment are described. Injuries to adults and children and the current trends in air bag injury rates are discussed, as are the few documented instances of inadvertent deployments or non-deployment in severe crashes. In the third section, an attempt is made to quantify the influence of the many confounding factors that affect air bag performance. The negative and positive characteristics of air bags are then put into perspective within the context of societal costs and benefits. Finally, some special topics, including risk homeostasis and the performance of face bags, are discussed.

  10. Effects of air pollution on human exercise performance

    SciTech Connect

    Frykman, P.N.

    1988-02-01

    The pollutants commonly experienced in cities of the United States are: carbon monoxide, ozone, peroxyacetyl nitrate, aerosols, sulfur dioxide, and nitrogen dioxide. Only carbon monoxide has been show to reduce exercise performance. The investigations which evaluated the impact of other pollutants on performance, may not have been sensitive enough to detect the small performance decrements caused. Suggested ways to avoid performance decrements are included.

  11. Autonomous Integrated Receive System (AIRS) requirements definition. Volume 3: Performance and simulation

    NASA Technical Reports Server (NTRS)

    Chie, C. M.; Su, Y. T.; Lindsey, W. C.; Koukos, J.

    1984-01-01

    The autonomous and integrated aspects of the operation of the AIRS (Autonomous Integrated Receive System) are discussed from a system operation point of view. The advantages of AIRS compared to the existing SSA receive chain equipment are highlighted. The three modes of AIRS operation are addressed in detail. The configurations of the AIRS are defined as a function of the operating modes and the user signal characteristics. Each AIRS configuration selection is made up of three components: the hardware, the software algorithms and the parameters used by these algorithms. A comparison between AIRS and the wide dynamics demodulation (WDD) is provided. The organization of the AIRS analytical/simulation software is described. The modeling and analysis is for simulating the performance of the PN subsystem is documented. The frequence acquisition technique using a frequency-locked loop is also documented. Doppler compensation implementation is described. The technological aspects of employing CCD's for PN acquisition are addressed.

  12. An Analysis of the Air Force Enlisted Performance Feedback System

    DTIC Science & Technology

    1992-09-01

    subjects giving and receiving the feedback from the various methods (DeGregorio and Fisher, 1988:605). The four types of techniques they studied in... receives some P.~ id~srn Hence, leadership gives support from upper-level ~potfo elw p no emphasis to a feedback management. Certain Io .a.........k...researchers’ analysis of the literature. The researchers found evidence that the new Air Force feedback system is an improvement over the old design. Under the

  13. Does small-sided-games’ court area influence metabolic, perceptual, and physical performance parameters of young elite basketball players?

    PubMed Central

    Marcelino, PR; Aoki, MS; Arruda, AFS; Freitas, CG; Mendez-Villanueva, A

    2015-01-01

    The purpose of this study was to investigate the effect of court size on physiological responses and physical performance of young elite basketball players. Twelve male basketball players (18.6 ± 0.5 years; 88.8 ± 14.5 kg; 192.6 ± 6.5 cm) from an under-19 team performed two small-sided games (matches) with different court areas (28x15 m and 28x9 m; 28x15 and 28x9 protocols). The number of players (3x3) was kept the same in each protocol. The players performed a repeated-sprint ability (RSA) test before and after each match. Blood lactate concentration was collected before (pre) and after (post) the matches, and the session rating of perceived exertion (session-RPE) was determined 30 minutes after the match. Best and mean time in the RSA test were not different between the 28x15 and the 28x9 match protocols (p > 0.05). A significant difference was observed for lactate concentration from pre- to post-match (p < 0.05) in both protocols (28x15 and 28x9); however, there was no significant interaction between protocols. A similar session-RPE mean score (28x15: 7.2 ± 1.4 and 28x9: 6.6 ± 1.4) was detected for both protocols (p > 0.05, ES=0.41). In summary, the results of the current study suggest that the different court areas induced similar responses. Although there was no significant difference in effort perception, players tended to perceive a greater effort in the larger court size. PMID:26985132

  14. Effects of a periodized small-sided game training intervention on physical performance in elite professional soccer.

    PubMed

    Owen, Adam L; Wong, Del P; Paul, Darren; Dellal, Alexandre

    2012-10-01

    The present study examined the effects of periodized small-sided game (SSG) training intervention during a 4-week in-season break on the physical performance changes (i.e., speed, aerobic performance, and repeated sprint ability) within elite European soccer players. Fifteen, elite, male, professional players (age: 24.5 ± 3.45 years; height: 181.1 ± 5.78 cm; body mass: 78.7 ± 7.67 kg; VO2max: 54.88 ± 5.25 ml·kg(-1)·min(-1)) from a Scottish Premier League team participated in 7 separate SSG sessions (3 vs. 3 plus goalkeepers) of which games lasted for a 3-minute duration for the selected number of games (ranged from 5 to 11) increasing over the intervention period. To examine the effects of the SSG intervention on physical performance changes, pre- and posttesting sessions took place over a 2-day period (day 1: anthropometry and repeated sprint ability [RSA] assessments; day 2: running economy [RE] and blood lactate assessments). Results show that the 4-week SSG training intervention induced significant improvement in RSA as indicated by faster 10-m sprint time (p < 0.05, small effect), total sprint time (p < 0.05, medium effect), and smaller percentage decrement score (p < 0.05, medium effect). Furthermore, the SSGs also led to an improvement in RE as indicated through significantly reduced VO2 and heart rate at running speed 9, 11, and 14 km·h(-1) (all p's < 0.05, large effects). In conclusion, the present study demonstrates that implementing a periodized SSG training intervention during the 4-week in-season break is capable of improving elite-level soccer players' physical fitness characteristics. Being able to develop physical characteristics in conjunction to technical and tactical elements of the game, within a relatively short period, makes SSGs an appealing proposition for fitness coaches, players, and technical coaches alike.

  15. Characterization of the LTC catalyst: Performance against common air pollutants

    NASA Technical Reports Server (NTRS)

    Collins, Marcia F.

    1987-01-01

    One of the important qualities of the Low-Temperature Catalyst (LTC) is the rapid oxidation of carbon monoxide to carbon dioxide under a wide variety of conditions. The catalytic material is a palladium-copper activated complex which reacts with various contaminant molecules through a continuous oxidation/reduction cycle. The alumina substrate enhances LTC activity with its favorable surface chemistry and very high surface area. About 10 percent surface water is necessary to facilitate the oxidation of CO. This reaction shows a log-log dependence on contact time, suggesting a Langmuir-Hinshelwood mechanism. In the tube tests, LTC removed 90 to 100 percent of contaminating carbon monoxide in the temperature region of 20 to 4000 C, and at ambient over a range of 25 to 65 percent relative humidity. In contrast, NO2 is chemisorbed by the LTC/alumina material--the amount strongly dependent on temperature increases but independent of humidity. The LTC catalyst has demonstrated excellent capability to remove an important variety of hazardous pollutant gases which are common factors to poor indoor air quality. The Instapure Air Filtration System incorporates the LTC catalyst in a 50:50 mixture with activated carbon to effectively remove particulate, odors, and hazardous gases at room temperature and humidities. The ability to remove hazardous gases is unique for the category of portable air filtration equipment. The wide variety of pollutant gases that LTC removes suggests that catalytic technology is adaptable to a considerable range of commercial and industrial applications.

  16. Air Force Civil Engineer Center Management of Energy Savings Performance Contracts Needs Improvement

    DTIC Science & Technology

    2016-05-04

    Force Civil Engineer Center Management of Energy Savings Performance Contracts Needs Improvement M A Y 4 , 2 0 1 6 Report No. DODIG-2016-087 Mission...Management of Energy Savings Performance Contracts Needs Improvement Visit us at www.dodig.mil Objective Our objective was to determine whether the Air...Force is effectively managing energy savings performance contracts (ESPCs). This report is the second in a series of audits on ESPCs. Finding The Air

  17. Creep Performance of Oxide Ceramic Fiber Materials at Elevated Temperature in Air and in Steam

    DTIC Science & Technology

    2011-03-24

    performance in harsh environments are prime candidates for such applications . Oxide ceramic materials have been used as constituents in CMCs...since 1965, when the United States Air Force led the effort to bring high performance fiber composites to practical applications [26]. Today...bulk polycrystalline alumina cubes were performed in air and steam at 1100 and 1300°C. Both the bulk alumina and YAG specimens were processed in two

  18. Maximizing Energy Savings Reliability in BC Hydro Industrial Demand-side Management Programs: An Assessment of Performance Incentive Models

    NASA Astrophysics Data System (ADS)

    Gosman, Nathaniel

    For energy utilities faced with expanded jurisdictional energy efficiency requirements and pursuing demand-side management (DSM) incentive programs in the large industrial sector, performance incentive programs can be an effective means to maximize the reliability of planned energy savings. Performance incentive programs balance the objectives of high participation rates with persistent energy savings by: (1) providing financial incentives and resources to minimize constraints to investment in energy efficiency, and (2) requiring that incentive payments be dependent on measured energy savings over time. As BC Hydro increases its DSM initiatives to meet the Clean Energy Act objective to reduce at least 66 per cent of new electricity demand with DSM by 2020, the utility is faced with a higher level of DSM risk, or uncertainties that impact the costeffective acquisition of planned energy savings. For industrial DSM incentive programs, DSM risk can be broken down into project development and project performance risks. Development risk represents the project ramp-up phase and is the risk that planned energy savings do not materialize due to low customer response to program incentives. Performance risk represents the operational phase and is the risk that planned energy savings do not persist over the effective measure life. DSM project development and performance risks are, in turn, a result of industrial economic, technological and organizational conditions, or DSM risk factors. In the BC large industrial sector, and characteristic of large industrial sectors in general, these DSM risk factors include: (1) capital constraints to investment in energy efficiency, (2) commodity price volatility, (3) limited internal staffing resources to deploy towards energy efficiency, (4) variable load, process-based energy saving potential, and (5) a lack of organizational awareness of an operation's energy efficiency over time (energy performance). This research assessed the capacity

  19. 77 FR 47617 - Change of Names Given for the Performance Review Board for the Department of the Air Force.

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-09

    ... Department of the Air Force Change of Names Given for the Performance Review Board for the Department of the Air Force. AGENCY: Department of the Air Force, DOD. ACTION: Notice. SUMMARY: Notice is given to replace a member of the 2012 Performance Review Board for the Department of the Air Force....

  20. Performance comparison of long and short-side chain perfluorosulfonic membranes for high temperature polymer electrolyte membrane fuel cell operation

    NASA Astrophysics Data System (ADS)

    Stassi, A.; Gatto, I.; Passalacqua, E.; Antonucci, V.; Arico, A. S.; Merlo, L.; Oldani, C.; Pagano, E.

    A new Aquivion™ E79-03S short-side chain perfluorosulfonic membrane with a thickness of 30 μm (dry form) and an equivalent weight (EW) of 790 g/equiv recently developed by Solvay-Solexis for high-temperature operation was tested in a pressurised (3 bar abs.) polymer electrolyte membrane (PEM) single cell at a temperature of 130 °C. For comparison, a standard Nafion™ membrane (EW 1100 g/equiv) of similar thickness (50 μm) was investigated under similar operating conditions. Both membranes were tested for high temperature operation in conjunction with an in-house prepared carbon supported Pt electrocatalyst. The electrocatalyst consisted of nanosized Pt particles (particle size ∼2 nm) dispersed on a high surface area carbon black. The electrochemical tests showed better performance for the Aquivion™ membrane as compared to Nafion™ with promising properties for high temperature PEM fuel cell applications. Beside the higher open circuit voltage and lower ohmic constraints, a higher electrocatalytic activity was observed at high temperature for the electrocatalyst-Aquivion™ ionomer interface indicating a better catalyst utilization.

  1. Functional performance testing of the universal super absorbing air filters FSU 70 „Air by Corneliu”

    NASA Astrophysics Data System (ADS)

    Raţiu, S.; Birtok-Băneasă, C.; Alexa, V.; Kiss, I.

    2015-06-01

    This paper presents the experimental methodology to carry out functional performance tests for an air filter with a particular design of its housing, generically named Universal super absorbing FSU 70 „Air by Corneliu”. The tests were carried out in the Internal Combustion Engines Laboratory, within the specialization "Road automotives" belonging to the Faculty of Engineering Hunedoara, component of “Politehnica” University of Timisoara. We present some comparative values of various operating parameters of the engine fitted, in the first measuring session, with the original filter, and then with the studied filter.

  2. Heating, Ventilating, and Air-Conditioning: Recent Advances in Diagnostics and Controls to Improve Air-Handling System Performance

    SciTech Connect

    Wray, Craig; Wray, Craig P.; Sherman, Max H.; Walker, I.S.; Dickerhoff, D.J.; Federspiel, C.C.

    2008-02-01

    The performance of air-handling systems in buildings needs to be improved. Many of the deficiencies result from myths and lore and a lack of understanding about the non-linear physical principles embedded in the associated technologies. By incorporating these principles, a few important efforts related to diagnostics and controls have already begun to solve some of the problems. This paper illustrates three novel solutions: one rapidly assesses duct leakage, the second configures ad hoc duct-static-pressure reset strategies, and the third identifies useful intermittent ventilation strategies. By highlighting these efforts, this paper seeks to stimulate new research and technology developments that could further improve air-handling systems.

  3. Effects of Air Pollution on Human Exercise Performance

    DTIC Science & Technology

    1988-01-01

    Perspective P’ Ilurawn Stindiards mdccx And the National Avcragc Air Quialmt M ~’ost of us would Ili to Ijyc, work Anti u:xcris- Ii A pristInu cnvirinmcnlt...livc Ii or TAO ussun1cltitI takctots .arc nocdcd h ir Ai smog probk ~ m to (c near a1 mctro pol it an Arc’..Thucsc citius. with iir actundant IFInduS...gunucratu. Ani cxamplc of A turrain trapl is thu arca Around I)univcr. C otora- Stagguring m !ounts of* pollution. Natural disaisturs such As firust do

  4. Toward server-side, high performance climate change data analytics in the Earth System Grid Federation (ESGF) eco-system

    NASA Astrophysics Data System (ADS)

    Fiore, Sandro; Williams, Dean; Aloisio, Giovanni

    2016-04-01

    In many scientific domains such as climate, data is often n-dimensional and requires tools that support specialized data types and primitives to be properly stored, accessed, analysed and visualized. Moreover, new challenges arise in large-scale scenarios and eco-systems where petabytes (PB) of data can be available and data can be distributed and/or replicated (e.g., the Earth System Grid Federation (ESGF) serving the Coupled Model Intercomparison Project, Phase 5 (CMIP5) experiment, providing access to 2.5PB of data for the Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report (AR5). Most of the tools currently available for scientific data analysis in the climate domain fail at large scale since they: (1) are desktop based and need the data locally; (2) are sequential, so do not benefit from available multicore/parallel machines; (3) do not provide declarative languages to express scientific data analysis tasks; (4) are domain-specific, which ties their adoption to a specific domain; and (5) do not provide a workflow support, to enable the definition of complex "experiments". The Ophidia project aims at facing most of the challenges highlighted above by providing a big data analytics framework for eScience. Ophidia provides declarative, server-side, and parallel data analysis, jointly with an internal storage model able to efficiently deal with multidimensional data and a hierarchical data organization to manage large data volumes ("datacubes"). The project relies on a strong background of high performance database management and OLAP systems to manage large scientific data sets. It also provides a native workflow management support, to define processing chains and workflows with tens to hundreds of data analytics operators to build real scientific use cases. With regard to interoperability aspects, the talk will present the contribution provided both to the RDA Working Group on Array Databases, and the Earth System Grid Federation (ESGF

  5. 78 FR 39594 - Safety Zone; Seafair Blue Angels Air Show Performance, Seattle, WA

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-02

    ... SECURITY Coast Guard 33 CFR Part 165 Safety Zone; Seafair Blue Angels Air Show Performance, Seattle, WA... enforce the annual Seafair Blue Angels Air Show safety zone on Lake Washington, Seattle, WA from 9 a.m. on August 2, 2013, to 4 p.m. on August 4, 2013. This safety zone is being enforced for the Patriots Jet...

  6. 76 FR 34867 - Safety Zone Regulations, Seafair Blue Angels Air Show Performance, Seattle, WA

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-15

    ... SECURITY Coast Guard 33 CFR Part 165 Safety Zone Regulations, Seafair Blue Angels Air Show Performance... Guard will enforce the annual Seafair Blue Angels Air Show safety zone on Lake Washington, Seattle, WA... enforcement period, no person or vessel may enter or transit this safety zone unless authorized by the...

  7. 16 CFR Appendix H to Part 305 - Cooling Performance and Cost for Central Air Conditioners

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... for Central Air Conditioners Manufacturer's rated cooling capacities (Btu's/hr.) Range of SEER's Low High Single Package Units Central Air Conditioners (Cooling Only): All capacities 10.6 16.5 Heat Pumps... 16 Commercial Practices 1 2014-01-01 2014-01-01 false Cooling Performance and Cost for Central...

  8. Improved detection of low vapor pressure compounds in air by serial combination of single-sided membrane introduction with fiber introduction mass spectrometry (SS-MIMS-FIMS).

    PubMed

    Cotte-Rodríguez, Ismael; Handberg, Eric; Noll, Robert J; Kilgour, David P A; Cooks, R Graham

    2005-05-01

    The use of two methods in tandem, single-sided membrane introduction mass spectrometry (SS-MIMS) and fiber introduction mass spectrometry (FIMS), is presented as a technique for field analysis. The combined SS-MIMS-FIMS technique was employed in both a modified commercial mass spectrometer and a miniature mass spectrometer for the selective preconcentration of the explosive simulant o-nitrotoluene (ONT) and the chemical warfare agent simulant, methyl salicylate (MeS), in air. A home-built FIMS inlet was fabricated to allow introduction of the solid-phase microextraction (SPME) fiber into the mass spectrometer chamber and subsequent desorption of the trapped compounds using resistive heating. The SS-MIMS preconcentration system was also home-built from commercial vacuum parts. Optimization experiments were done separately for each preconcentration system to achieve the best extraction conditions prior to use of the two techniques in combination. Improved limits of detection, in the low ppb range, were observed for the combination compared to FIMS alone, using several SS-MIMS preconcentration cycles. The SS-MIMS-FIMS response for both instruments was found to be linear over the range 50 to 800 ppb. Other parameters studied were absorption time profiles, effects of sample flow rate, desorption temperature, fiber background, memory effects, and membrane fatigue. This simple, sensitive, accurate, robust, selective, and rapid sample preconcentration and introduction technique shows promise for field analysis of low vapor pressure compounds, where analyte concentrations will be extremely low and the compounds are difficult to extract from a matrix like air.

  9. Effects of the arrangement of triangle-winglet-pair vortex generators on heat transfer performance of the shell side of a double-pipe heat exchanger enhanced by helical fins

    NASA Astrophysics Data System (ADS)

    Zhang, Li; Shang, Bojun; Meng, Huibo; Li, Yaxia; Wang, Cuihua; Gong, Bin; Wu, Jianhua

    2017-01-01

    To improve heat transfer performance of the shell side of a double-pipe heat exchanger enhanced by helical fins, triangle-winglet-pair vortex generators (VG) were installed along the centerline of the helical channel with rectangular cross section. The effects of the arrangement of the triangle-winglet-pair VG, such as the geometry, the angle of attack and the quantity on heat transfer performance and pressure drop characteristics have been investigated experimentally to find out the optimal design of the VG. Air was used as working fluid within the range of Re from 680 to 16,000. The results show that, the heat exchange effectiveness of the shell side with VG is 16.6 % higher than that without VG. The vortices and the unsteadiness of the flow introduced by the VG make a great contribution to the increase. Under identical pressure drop condition, the angle of attack of 30° is the best choice compared with 45° and 60°. Under the three constraints, i.e., identical mass flow rate, identical pressure drop and identical pumping power, the largest VG size can achieve the best enhancement effect. Installation of three pairs of VG within one pitch is an optimal design for the shell side used in the present experiments. The enhancement effect of isosceles right triangle is better than that of right triangle in which one acute angle is 30°.

  10. 78 FR 12598 - Safety Zone; Seafair Blue Angels Air Show Performance, Seattle, WA

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-25

    ... Seafair Blue Angels Air Show Performance, which include low flying high speed aircraft, and will do so by... potential accidents caused by these low-flying military aircraft. The regulation contained in 33 CFR...

  11. A Performance Evaluation of the National Air Quality Forecast Capability for the Summer of 2007

    EPA Science Inventory

    This paper provides a performance evaluation of the real-time, CONUS-scale National Air Quality Forecast Capability (NAQFC), developed collaboratively by the National Oceanic and Atmospheric Administration (NOAA) and Environmental Protection Agency (EPA), that supported, in part,...

  12. COMPUTATIONS ON THE PERFORMANCE OF PARTICLE FILTERS AND ELECTRONIC AIR CLEANERS

    EPA Science Inventory

    The paper discusses computations on the performance of particle filters and electronic air cleaners (EACs). The collection efficiency of particle filters and ACs is calculable if certain factors can be assumed or calibrated. For fibrous particulate filters, measurement of colle...

  13. PERFORMANCE OF ACTIVATED SLUDGE-POWDERED ACTIVATED CARBON-WET AIR REGENERATION SYSTEMS

    EPA Science Inventory

    The investigation summarized in the report was undertaken to evaluate the performance of powdered activated carbon (PAC) technology used in conjunction with wet air regeneration (WAR) at municipal wastewater treatment plants. Excessive ash concentrations accumulated in the mixed ...

  14. Experimental investigation of air pressure affecting filtration performance of fibrous filter sheet.

    PubMed

    Xu, Bin; Yu, Xiao; Wu, Ya; Lin, Zhongping

    2017-03-01

    Understanding the effect of air pressure on their filtration performance is important for assessing the effectiveness of fibrous filters under different practical circumstances. The effectiveness of three classes of air filter sheets were investigated in laboratory-based measurements at a wide range of air pressures (60-130 KPa). The filtration efficiency was found most sensitive to the air pressure change at smaller particle sizes. As the air pressure increased from 60 to 130 KPa, significant decrease in filtration efficiency (up to 15%) and increase in pressure drop (up to 90 Pa) were observed. The filtration efficiency of the filter sheet with largest fiber diameter and smallest solid volume fraction was affected most, while the pressure drop of the filter sheet with smallest fiber diameter and largest solid volume fraction was affected most. The effect of air pressure on the filtration efficiency was slightly larger at greater filter face air velocity. However, the effect of air pressure on the pressure drop was negligible. The filtration efficiency and pressure drop were explicitly expressed as functions of the air pressure. Two coefficients were empirically derived and successfully accounted for the effects of air pressure on filtration efficiency and pressure drop.

  15. High-Performance Lithium-Air Battery with a Coaxial-Fiber Architecture.

    PubMed

    Zhang, Ye; Wang, Lie; Guo, Ziyang; Xu, Yifan; Wang, Yonggang; Peng, Huisheng

    2016-03-24

    The lithium-air battery has been proposed as the next-generation energy-storage device with a much higher energy density compared with the conventional lithium-ion battery. However, lithium-air batteries currently suffer enormous problems including parasitic reactions, low recyclability in air, degradation, and leakage of liquid electrolyte. Besides, they are designed into a rigid bulk structure that cannot meet the flexible requirement in the modern electronics. Herein, for the first time, a new family of fiber-shaped lithium-air batteries with high electrochemical performances and flexibility has been developed. The battery exhibited a discharge capacity of 12,470 mAh g(-1) and could stably work for 100 cycles in air; its electrochemical performances were well maintained under bending and after bending. It was also wearable and formed flexible power textiles for various electronic devices.

  16. Performance of Commercially Available Flame Arrestors for Butane/Air and Gasoline/Air Mixtures

    DTIC Science & Technology

    1978-09-01

    Model TBA16-3-O-3, 465 SCFM, 16 oz. capacity) by way of a 4-inch diameter by 4-feet long pipe which incorporates a Meriam Model 50MY15-4 Laminar...fuel supply tank incorporated a Meriam Model 50W20 1F LFE flowmeter, a Jenkins manual throttling valve, a manual shut-off cock, an ASCO 8210854 solenoid... Meriam Model A-844 manometer used to measure the pressure drop. Air temperature was measured using a Grounded sheath type thermocouple (Omega Type CAIN

  17. Comparative Performance of Male and Female Enlistees on Air Force Selection Measures.

    ERIC Educational Resources Information Center

    Vitola, Bert M.; Wilbourn, James M.

    Male and female enlistee samples were compared for total groups and by enlistment region in terms of their performance on the Airman Qualifying Examination and the Armed Services Vocational Aptitude Battery. Women in the Air Force test-retest performance were evaluated on the Armed Forces Women's Selection Test. WAF performance on the AFWST was…

  18. Preliminary performance estimates of an oblique, all-wing, remotely piloted vehicle for air-to-air combat

    NASA Technical Reports Server (NTRS)

    Nelms, W. P., Jr.; Bailey, R. O.

    1974-01-01

    A computerized aircraft synthesis program has been used to assess the effects of various vehicle and mission parameters on the performance of an oblique, all-wing, remotely piloted vehicle (RPV) for the highly maneuverable, air-to-air combat role. The study mission consists of an outbound cruise, an acceleration phase, a series of subsonic and supersonic turns, and a return cruise. The results are presented in terms of both the required vehicle weight to accomplish this mission and the combat effectiveness as measured by turning and acceleration capability. This report describes the synthesis program, the mission, the vehicle, and results from sensitivity studies. An optimization process has been used to establish the nominal RPV configuration of the oblique, all-wing concept for the specified mission. In comparison to a previously studied conventional wing-body canard design for the same mission, this oblique, all-wing nominal vehicle is lighter in weight and has higher performance.

  19. Performance and costs of particle air filtration technologies.

    PubMed

    Fisk, W J; Faulkner, D; Palonen, J; Seppanen, O

    2002-12-01

    This paper predicts the reductions in the indoor mass concentrations of particles attainable from use of filters in building supply airstreams and also from use of stand-alone fan-filter units. Filters with a wide efficiency range are considered. Predicted concentration reductions are provided for indoor-generated particles containing dust-mite and cat allergen, for environmental tobacco smoke (ETS) particles, and for outdoor air fine-mode particles. Additionally, this paper uses a simple model and available data to estimate the energy and total costs of the filtration options. Predicted reductions in cat and dust-mite allergen concentrations range from 20 to 80%. To obtain substantial, e.g. 50%, reductions in indoor concentrations of these allergens, the rate of airflow through the filter must be at least a few indoor volumes per hour. Increasing filter efficiencies above approximately ASHRAE Dust Spot 65% does not significantly reduce predicted indoor concentrations of these allergens. For ETS particles and outdoor fine-mode particles, calculations indicate that relatively large, e.g. 80%, decreases in indoor concentrations are attainable with practical filter efficiencies and flow rates. Increasing the filter efficiency above ASHRAE 85% results in only modest predicted incremental decreases in indoor concentration. Energy costs and total costs can be similar for filtration using filters with a wide range of efficiency ratings. Total estimated filtration costs of approximately $0.70 to $1.80 per person per month are insignificant relative to salaries, rent, or health insurance costs.

  20. Influence of Ventilation Ratio on Desiccant Air Conditioning System's Efficiency Performance

    NASA Astrophysics Data System (ADS)

    Tran, Thien Nha; Akisawa, Atsushi; Kashiwagi, Takao; Hamamoto, Yoshinori

    Ventilation air is a concern for engineers since ventilated air controls indoor air contamination; additional ventilation, however, increases the energy consumption of buildings. The study investigates the energy efficiency performance of the desiccant dehumidification air conditioning system in the context of ventilation for a hot-humid climate such as summer in Japan. The investigation focuses on the variable ratio of ventilation air as required by the application of air conditioning system. The COP of the desiccant air conditioning system is determined. The evaluation is subsequently performed by comparing the desiccant based system with the conventional absorption cooling system and the vapor compression cooling system. Based on 12 desiccant rotor simulations, it is found that the desiccant regeneration temperature required varies between 47°C to 85°C as ventilation ratio increases from 0. 0 to 100%, and up to 52. 5°C as the ventilation ratio achieves 14%. The heat required for regenerating desiccant accounts for 55% and higher of the system's total heat consumption; the system is expected to be energy efficient by using wasted heat from the absorption chiller for desiccant regeneration; and its energy efficiency expands as the ratio of ventilation air rises above 15% compared with the conventional absorption cooling system. The energy efficiency also benefits as the ratio rises beyond 70% against the conventional vapor compression cooling system.

  1. Performance Data Errors in Air Carrier Operations: Causes and Countermeasures

    NASA Technical Reports Server (NTRS)

    Berman, Benjamin A.; Dismukes, R Key; Jobe, Kimberly K.

    2012-01-01

    Several airline accidents have occurred in recent years as the result of erroneous weight or performance data used to calculate V-speeds, flap/trim settings, required runway lengths, and/or required climb gradients. In this report we consider 4 recent studies of performance data error, report our own study of ASRS-reported incidents, and provide countermeasures that can reduce vulnerability to accidents caused by performance data errors. Performance data are generated through a lengthy process involving several employee groups and computer and/or paper-based systems. Although much of the airline indUStry 's concern has focused on errors pilots make in entering FMS data, we determined that errors occur at every stage of the process and that errors by ground personnel are probably at least as frequent and certainly as consequential as errors by pilots. Most of the errors we examined could in principle have been trapped by effective use of existing procedures or technology; however, the fact that they were not trapped anywhere indicates the need for better countermeasures. Existing procedures are often inadequately designed to mesh with the ways humans process information. Because procedures often do not take into account the ways in which information flows in actual flight ops and time pressures and interruptions experienced by pilots and ground personnel, vulnerability to error is greater. Some aspects of NextGen operations may exacerbate this vulnerability. We identify measures to reduce the number of errors and to help catch the errors that occur.

  2. 78 FR 63459 - Names of Members of the Performance Review Board for the Department of the Air Force

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-24

    ... Department of the Air Force Names of Members of the Performance Review Board for the Department of the Air... for the Department of the Air Force. DATES: Effective Date: November 4, 2013. SUPPLEMENTARY INFORMATION: Pursuant to 5 U.S.C. 4314(c) (1-5), the Department of the Air Force (AF) announces...

  3. Performance Evaluation of Industrial Hygiene Air Monitoring Sensors

    SciTech Connect

    Maughan, A D.; Glissmeyer, John A.; Birnbaum, Jerome C.

    2004-12-10

    Tests were performed to evaluate the accuracy, precision and response time of certain commercially available handheld toxic gas monitors. The tests were conducted by PNNL in the Chemical Chamber Test Facility for CH2MHill Hanford Company. The instruments were tested with a set of dilute test gases including ammonia, nitrous oxide, and a mixture of organic vapors (acetone, benzene, ethanol, hexane, toluene and xylene). The certified gases were diluted to concentrations that may be encountered in the outdoor environment above the underground tank farms containing radioactive waste at the U.S. Department of Energy's Hanford site, near Richland, Washington. The challenge concentrations are near the lower limits of instrument sensitivity and response time. The performance test simulations were designed to look at how the instruments respond to changes in test gas concentrations that are similar to field conditions.

  4. Performance Evaluation of Industrial Hygiene Air Monitoring Sensors, Revision 1

    SciTech Connect

    Maughan, A D.; Glissmeyer, John A.; Birnbaum, Jerome C.

    2005-01-24

    Tests were performed to evaluate the accuracy, precision and response time of certain commercially available handheld toxic gas monitors. The tests were conducted by PNNL in the Chemical Chamber Test Facility for CH2MHill Hanford Company. The instruments were tested with a set of dilute test gases including ammonia, nitrous oxide, and a mixture of organic vapors (acetone, benzene, ethanol, hexane, toluene and xylene). The certified gases were diluted to concentrations that may be encountered in the outdoor environment above the underground tank farms containing radioactive waste at the U.S. Department of Energy's Hanford site, near Richland, Washington. The challenge concentrations are near the lower limits of instrument sensitivity and response time. The performance test simulations were designed to look at how the instruments respond to changes in test gas concentrations that are similar to field conditions.

  5. Deployable Air Beam Fender System (DAFS): Energy Absorption Performance Analysis

    DTIC Science & Technology

    2007-03-30

    its energy absorption performance. Quarter-scale and full-scale models were evaluated and compared to protot ype tests for a variety of inflation...pressures, impact berthing conditions, and ballast levels. Model predictions were validated with correlated test data. The explicit FEA method captured...was used. In step 1, the fender was inflated to the specified inflation pressure and the acceleration caused by gravity (386.4 in./s 2) was applied

  6. Analysis of Air Force Wartime Contracted Construction Project Performance

    DTIC Science & Technology

    2015-03-26

    peacetime factors as a baseline, project factors, health and safety compliance, quality of work, technical performance, work productivity, and...significant difference in overall project quality . In conclusion, cost monitoring from the owner and scrutiny of project management is critical to the...sponsor’s need for the research, and finishes with a brief description of the scope and methodology for the paper . 2 The AFCEC program, though

  7. Evaluation of 5-cm Centrifugal Contactor Hydraulic and Mass Transfer Performance for Caustic-Side Solvent Extraction of Cesium

    SciTech Connect

    Birdwell, J.F.

    2001-09-12

    A test program has been conducted in which the use of pilot-scale centrifugal solvent extraction contactors for cesium removal from an alkaline waste stream has been successfully demonstrated. The program was designed specifically to evaluate the use of centrifugal contactors having 5-cm-diam rotors for the removal of cesium from alkaline high-level waste (HLW) that was generated and is being stored at the U.S. Department of Energy's Savannah River Site (SRS). The removal of cesium from this waste is highly desirable because it will reduce the volume of waste that must be treated and disposed of as HLW. The parameters applied in the test effort are those that have been established for the Caustic-Side Solvent Extraction (CSSX) process, a multistage extraction operation that has been designed by researchers at Oak Ridge National Laboratory (ORNL) and Argonne National Laboratory (ANL). In the CSSX process, cesium is extracted by calix(4)arene-bis-(fert-octylbenzo-crown-6), commonly referred to as BOBCalixC6. The extract is scrubbed with dilute (0.05 M) nitric acid, both to remove coextracted elements (primarily potassium and sodium) and to adjust the pH of the extract to facilitate recovery of the cesium. The scrubbed solvent is contacted with 0.001 M HNO{sub 3}, which results in the stripping of the cesium from the solvent into the aqueous acid. The CSSX process flow rates have been established so to produce a cesium concentration in the strip effluent that is 12 to 15 times the concentration in the waste stream that enters the extraction section of the cascade. Results from initial hydraulic testing of a commercially available 5-cm contactor under CSSX conditions indicated that the mixing of feed solutions within the unit (which is critical to efficient solute transfer) was limited by a feature of the contactor that was designed to increase throughput and improve separation performance. In the design, phase separation is improved by reducing turbulence within the

  8. Effect of vehicle type on the performance of second generation air bags for child occupants.

    PubMed

    Arbogast, Kristy B; Durbin, Dennis R; Kallan, Michael J; Winston, Flaura K

    2003-01-01

    Passenger air bags experienced considerable design modification in the late 1990s, principally to mitigate risks to child passengers. This study utilized Data from the Partners for Child Passenger Safety study, a large-scale child-focused crash surveillance system, to examine the effect of vehicle type on the differential performance of first and second generation air bags on injuries to restrained children in frontal impact crashes. Our results show that the benefit of second-generation air bags was seen in passenger cars - those children exposed to second-generation air bags were half as likely to sustain a serious injury - and minivans. However, in SUVs the data suggest no reduction in injury risk with the new designs. This field data provides crucial real-world experience to the automotive industry as they work towards the next generation of air bag designs.

  9. Performance of coherent detection for FTN-DFTs-OFDM signal using receiver-side quadrature duobinary shaping

    NASA Astrophysics Data System (ADS)

    Xu, Cheng; Gao, Guanjun; Chen, Sai; Zhang, Jie

    2016-12-01

    In this paper we investigate Faster-than-Nyquist Discrete-Fourier-Transform spread Orthogonal Frequency Division Multiplexing (FTN-DFTs-OFDM) signaling which combines the features of both single carrier FTN and OFDM system. By introducing the quadrature duo-binary (QDB) filtering at the receiver side, the transmitted OFDM signal can be packed in a sub-Nyquist spacing, which improves the spectral efficiency (SE) compared to conventional detection schemes. Maximum a posteriori (MAP) and maximum likelihood sequence estimation (MLSE) criteria have been both used and compared to find an optimal equalization scheme for combating FTN multiplexing at transmitter side and QDB filtering at receiver side. The simulations result show that by applying QDB filtering at the receiver side, the back-to-back (BTB) required optical signal noise ratio (OSNR) at bit error rate (BER) of 1 × 10-2 is reduced by 1.5-dB for 20-GHz spaced 128-Gb/s polarization-division-multiplexed quadrature-phase-shift-keying (PDM-QPSK) signal, achieving a SE of 6.4-b/s/Hz.

  10. MOPADS (Models of Operator Performance in Air Defense Systems)

    DTIC Science & Technology

    1984-11-01

    selects the next Operator Task which an FUNCTION operator will perform. The selection is based upon operator goal seeking character - .- istics. 1-8 󈨑...BACKGROUND CHARACTERS 21 MESSAGE BACKLOG 22 SIGNALS PER MINUTE 23 HOURS WORKED PER WEEK 24 DAYS WITHOUT SLEEP 25 DAYS OF NIGHT DUTY 26 SIMULTANEOUS...up. 111-20 N1 -LJI L6 La I =1 0 () , co a E- a A E" a- ,2 = I- ( Drx 0 00 0 a. coCIc uI.1 L) 4.3a x -P~ 00 IH 000 0 ;. .a = ’) (U (CJ a d a) 01 k -- 4 a

  11. Differences in creep performance of a HIPed silicon nitride in ambient air and inert environments

    SciTech Connect

    Wereszczak, A.A.; Kirkland, T.P.; Ferber, M.K.

    1995-04-01

    High temperature tensile creep studies of a commercially available hot isostatically pressed (HIPed) silicon nitride were conducted in ambient air and argon environments. The creep performance of this HIPed silicon nitride was found to be different in these environments. The material crept faster (and had a consequential shorter lifetime) in argon than in ambient air at 1370{degrees}C at tensile stresses between 110-140 MPa. The stress dependence of the minimum creep rate was found to be {approx} 6 in argon and {approx} 3.5 in air, while the minimum creep rates were almost an order of magnitude faster in argon than in air at equivalent tensile stresses. Differences in the creep performance are explained with reference to the presence or absence of oxygen in the two environments.

  12. Design and performance of a trickling air biofilter for chlorobenzene and o-dichlorobenzene vapors.

    PubMed Central

    Oh, Y S; Bartha, R

    1994-01-01

    From contaminated industrial sludge, two stable multistrain microbial enrichments (consortia) that were capable of rapidly utilizing chlorobenzene and o-dichlorobenzene, respectively, were obtained. These consortia were characterized as to their species composition, tolerance range, and activity maxima in order to establish and maintain the required operational parameters during their use in biofilters for the removal of chlorobenzene contaminants from air. The consortia were immobilized on a porous perlite support packed into filter columns. Metered airstreams containing the contaminant vapors were partially humidified and passed through these columns. The vapor concentrations prior to and after biofiltration were measured by gas chromatography. Liquid was circulated concurrently with the air, and the device was operated in the trickling air biofilter mode. The experimental arrangement allowed the independent variation of liquid flow, airflow, and solvent vapor concentrations. Bench-scale trickling air biofilters removed monochlorobenzene, o-dichlorobenzene, and their mixtures at rates of up to 300 g of solvent vapor h(-1) m(-3) filter volume. High liquid recirculation rates and automated pH control were critical for stable filtration performance. When the accumulating NaCl was periodically diluted, the trickling air biofilters continued to remove chlorobenzenes for several months with no loss of activity. The demonstrated high performance and stability of the described trickling air biofilters favor their use in industrial-scale air pollution control. PMID:8085815

  13. PacRIM II: A review of AirSAR operations and system performance

    NASA Technical Reports Server (NTRS)

    Moller, D.; Chu, A.; Lou, Y.; Miller, T.; O'Leary, E.

    2001-01-01

    In this paper we briefly review the AirSAR system, its expected performance, and quality of data obtained during that mission. We discuss the system hardware calibration methodologies, and present quantitative performance values of radar backscatter and interferometric height errors (random and systematic) from PACRIM II calibration data.

  14. Link Performance Analysis for a Proposed Future Architecture of the Air Force Satellite Control Network

    DTIC Science & Technology

    2011-12-01

    Force Institute of Technology Air University Air Education and Training Command In Partial Fulfillment of the Requirements for the Degree of...computing is an interesting approach to link performance prediction. A paper was authored by the Global Educational Network for Spacecraft Operations...GENSO is a conglomerate of multiple ground stations shared by educational organizations most of which need access to LEO spacecraft. As with any

  15. 75 FR 37711 - Automatic Dependent Surveillance-Broadcast (ADS-B) Out Performance Requirements To Support Air...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-30

    ..., Performance and Interoperability Requirements Document for Enhanced Air Traffic in Radar-Controlled Areas..., Performance and Interoperability Requirements Document for Enhanced Air Traffic in Radar-Controlled Areas... Interoperability Requirements Document for Enhanced Air Traffic in Radar-Controlled Areas Using ADS-B...

  16. Experimental investigation on performance of ice storage air-conditioning system with separate heat pipe

    SciTech Connect

    Fang, Guiyin; Liu, Xu; Wu, Shuangmao

    2009-11-15

    An experimental study on operation performance of ice storage air-conditioning system with separate helical heat pipe is conducted in this paper. The experimental system of ice storage air-conditioning system with separate heat pipe is set up. The performance parameters such as the evaporation pressure and the condensation pressure of refrigeration system, the refrigeration capacity and the COP (coefficient of performance) of the system, the IPF (ice packing factor) and the cool storage capacity in the cool storage tank during charging period, and the cool discharge rate and the cool discharge capacity in the cool storage tank, the outlet water temperature in the cool storage tank and the outlet air temperature in room unit during discharging period are investigated. The experimental results show that the ice storage air-conditioning system with separate helical heat pipe can stably work during charging and discharging period. This indicates that the ice storage air-conditioning system with separate helical heat pipe is well adapted to cool storage air-conditioning systems in building. (author)

  17. Influence of cathode opening size and wetting properties of diffusion layers on the performance of air-breathing PEMFCs

    NASA Astrophysics Data System (ADS)

    Schmitz, A.; Tranitz, M.; Eccarius, S.; Weil, A.; Hebling, C.

    Air-breathing PEMFCs consist of an open cathodic side to allow an entirely passive supply of oxygen by diffusion. Furthermore, a large fraction of the produced water is removed by evaporation from the open cathode. Gas diffusion layers (GDLs) and the opening size of the cathode have a crucial influence on the performance of an air-breathing PEMFC. In order to assure an unobstructed supply of oxygen the water has to be removed efficiently and condensation in the GDL has to be avoided. On the other hand good humidification of the membrane has to be achieved to obtain high protonic conductivity. In this paper the influence of varying cathodic opening sizes (33%, 50% and 80% opening ratios) and of GDLs with different wetting properties are analysed. GDLs with hydrophobic and hydrophilic properties are prepared by coating of untreated GDLs (Toray ® carbon paper TGP-H-120, thickness of 350 μm). The air-breathing PEMFC test samples are realised using printed circuit board (PCB) technology. The cell samples were characterised over the entire potential range (0-0.95 V) by extensive measurements of the current density, the temperature and the cell impedance at 1 kHz. Additionally, measurements of the water balance were carried out at distinct operation points. The best cell performance was achieved with the largest opening ratio (80%) and an untreated GDL. At the maximum power point, this cell sample achieved a power density of 100 mW cm -2 at a moderate cell temperature of 43 °C. Furthermore, it could be shown that GDLs with hydrophilic or intense hydrophobic properties do not improve the performance of an air-breathing PEMFC. Based on the extensive characterisations, two design rules for air-breathing PEMFCs could be formulated. Firstly, it is crucial to maximise the cathode opening as far as an appropriate compression pressure of the cell assembly and therewith low contact resistance can be assured. Secondly, it is advantageous to use an untreated, slightly hydrophobic

  18. Measured Performance of a Low Temperature Air Source Heat Pump

    SciTech Connect

    Johnson, R. K.

    2013-09-01

    A 4-ton Low Temperature Heat Pump (LTHP) manufactured by Hallowell International was installed in a residence near New Haven, Connecticut and monitored over two winters of operation. After attending to some significant service issues, the heat pump operated as designed. This report should be considered a review of the dual compressor 'boosted heat pump' technology. The Low Temperature Heat Pumpsystem operates with four increasing levels of capacity (heat output) as the outdoor temperature drops. The system was shown to select capacity correctly, supplying the appropriate amount of heat to the house across the full range of outdoor temperatures. The system's Coefficient of Performance (Seasonal COP, or SCOP) over two entire winters was calculated, based on measured data, to be 3.29over the first winter and 2.68 over the second winter. A second seasonal efficiency calculation by a different method yielded a SCOP of 2.78 for the first winter and 2.83 for the second winter. This second seasonal efficiency calculation was determined by comparing measured heat pump energy use to the in situ energy use with resistance heat alone. This method is the ratio of the slopes of thedaily energy use load lines.

  19. Advanced zinc-air batteries based on high-performance hybrid electrocatalysts.

    PubMed

    Li, Yanguang; Gong, Ming; Liang, Yongye; Feng, Ju; Kim, Ji-Eun; Wang, Hailiang; Hong, Guosong; Zhang, Bo; Dai, Hongjie

    2013-01-01

    Primary and rechargeable Zn-air batteries could be ideal energy storage devices with high energy and power density, high safety and economic viability. Active and durable electrocatalysts on the cathode side are required to catalyse oxygen reduction reaction during discharge and oxygen evolution reaction during charge for rechargeable batteries. Here we developed advanced primary and rechargeable Zn-air batteries with novel CoO/carbon nanotube hybrid oxygen reduction catalyst and Ni-Fe-layered double hydroxide oxygen evolution catalyst for the cathode. These catalysts exhibited higher catalytic activity and durability in concentrated alkaline electrolytes than precious metal Pt and Ir catalysts. The resulting primary Zn-air battery showed high discharge peak power density ~265 mW cm(-2), current density ~200 mA cm(-2) at 1 V and energy density >700 Wh kg(-1). Rechargeable Zn-air batteries in a tri-electrode configuration exhibited an unprecedented small charge-discharge voltage polarization of ~0.70 V at 20 mA cm(-2), high reversibility and stability over long charge and discharge cycles.

  20. Aids to Navigation Principal Findings Report: The Effect of One-Side Channel Markings and Related Conditions on Piloting Performance.

    DTIC Science & Technology

    1981-12-01

    will be selected at critical data lines and tested for the significance of their differences by the following procedures which are described in McNemar ...dictated by the logic of the comparisons. They will be compared as variances, using variance ratios, or an F-test. 25ouinn McNemar . Psycholoqical...1980. Eclectech Associates. "Preliminary Observations of the One-Sided Channel Marking Experiment, April 1981. McNemar , Quinn. Psychological

  1. Cold-air performance of a tip turbine designed to drive a lift fan. 1: Baseline performance

    NASA Technical Reports Server (NTRS)

    Haas, J. E.; Kofskey, M. G.; Hotz, G. M.; Futral, S. M., Jr.

    1976-01-01

    Full admission baseline performance was obtained for a 0.4 linear scale of the LF460 lift fan turbine over a range of speeds and pressure ratios without leakage air. These cold-air tests covered a range of speeds from 40 to 140 percent of design equivalent speed and a range of scroll inlet to diffuser exit static pressure ratios from 2.0 to 4.2. Results are presented in terms of specific work, torque, mass flow, efficiency, and total pressure drop.

  2. Improving the performance of a compression ignition engine by directing flow of inlet air

    NASA Technical Reports Server (NTRS)

    Kemper, Carlton

    1946-01-01

    The object of this report is to present the results of tests performed by the National Advisory Committee for Aeronautics to determine the effect on engine performance of directing the flow of the inlet air to a 5-inch by 7-inch cylinder, solid injection, compression ignition engine, After a few preliminary tests, comparative runs were made at a speed of 1500 r.p.m. with and without directed air flow. It was found that directing the flow of the inlet air toward the fuel injection valve gave steadier engine operation, and an appreciable increase in power, and decreased fuel consumption. The results indicate the possibility of improving the performance of a given type of combustion chamber without changing its shape and with no change in valve timing. They would also seem to prove that directional turbulence, set up before the inlet valve of a four-stroke cycle engine, continues in the engine cylinder throughout the compression stroke.

  3. Influence of Enhanced O2 Provision on the Discharge Performance of Li-air Batteries by Incorporating Fluoroether.

    PubMed

    Wan, Hao; Mao, Ya; Liu, Zixuan; Bai, Qingyou; Peng, Zhe; Bao, Jingjing; Wu, Gang; Liu, Yang; Wang, Deyu; Xie, Jingying

    2017-01-29

    As the first step during discharge, the mass transfer of oxygen should play a crucial role in Li-air batteries to tailor the growth of discharge products, however, not enough attention has been paid to this issue. Herein, we introduce an oxygen-enriching cosolvent, 1,2-(1,1,2,2-tetrafluoroethoxy) ethane (FE1), into the electrolyte, and investigate its influence on the discharge performance. The incorporation of this novel cosolvent consistently enhances the oxygen solubility of the electrolyte, and improves the oxygen diffusivity following a volcano-shape trend peaking at 50 % FE1. It is interesting that the discharge capacities obtained with the investigated electrolytes share the similar volcano trends as the oxygen transport under 50 mA gcarbon(-1) and higher current densities. The improved oxygen diffusion could benefit the volumetric utilization of the air cathode, especially at the separator side, probably owing to the fast oxygen transport to moderate its concentration gradient. Our results demonstrate the importance of oxygen provision, which easily becomes the capacity-determining factor.

  4. Experimental study on heat transfer performance of aluminium foam parallel-flow condenser in air conditioner

    NASA Astrophysics Data System (ADS)

    Zhang, X.; Wan, Z. M.; Chang, H. W.; Wang, Y. D.

    2017-01-01

    Open cell aluminium foam was used in parallel-flow condenser in air conditioner, and two condensers with different pore density were fabricated. The experimental study was conducted on the heat transfer performance and temperature distribution. The experimental results show that both of the heat transfer load and air pressure drop increase with the increase of pore density, air velocity is 2.5m/s, the heat transfer capacities of the condenser with 10PPI and 8PPI are 4.786kw and 3.344kW respectively. Along the flow direction of refrigerant, the outlet temperatures of refrigerant drop with the rise of air velocity when the inlet temperature is constant. The outlet temperature of the refrigerant decreases with the increase of pore density.

  5. Stress and physiological, behavioral and performance patterns of children under varied air ion levels

    NASA Astrophysics Data System (ADS)

    Fornof, K. T.; Gilbert, G. O.

    1988-12-01

    The possibility that individual differences in reactivity to stressors are a major factor underlying discordant results reported for air ion studies prompted an investigation of response patterns in school children under both normal indoor air ion levels and moderately increased negative air ion levels (4000±500/cm3). It was hypothesized that the impact of stressors is reduced with high negative air ionization, and that resultant changes in stress effects would be differentially exhibited according to the children's normal degree of stimulus reactivity. A counter-balanced, replicative, withinssubject design was selected, and the subjects were 12 environmentally sensitive, 1st 4th grade school children. In addition to monitoring stress effects on activity level, attention span, concentration to task and conceptual performance, measures were also made of urinary 5-hydroxyindole acetic acid levels and skin resistance response (SRR) to determine if changes extended to the physiological state. The cold water test was used to add physical stress and enable calculations of Lacey's autonomic lability scores (ALS) as indicators of individual reactivity. The results show main effects for air ions on both physiological parameters, with 48% less change in %SRR ( P<0.01) and 46% less change in urinary 5-HIAA levels ( P<0.055) during negative air ions, indicating increased stress tolerance. Strong interactive effects for ALS x air ion condition appeared, with high and low ALS children reacting oppositely to negative air ions in measures of skin resistance level ( P<0.01), wrist activity ( P<0.01) and digit span backwards ( P<0.004). Thus individual differences in autonomic reactivity and the presence or absence of stressors appear as critical elements for internal validity, and in preventing consequent skewed results from obscuring progress in air ion research.

  6. Effect of air supplement on the performance of continuous ethanol fermentation system.

    PubMed

    Ryu, D D; Kim, Y J; Kim, J H

    1984-01-01

    For the purpose of improving ethanol productivity, the effect of air supplement on the performance of continuous ethanol fermentation system was studied. The effect of oxygen supplement on yeast concentration, cell yield, cell viability, extracellular ethanol concentration, ethanol yield, maintenance coefficient, specific rates of glucose assimilation, ethanol production, and ethanol productivity have been evaluated, using a high alcohol tolerant Saccharomyces cerevisiae STV89 strain and employing a continuous fermentor equipped with an accurate air metering system in the flow rate range 0-11 mL air/L/h. It was found that, when a small amount of oxygen up to about 80mu mol oxygen/L/h was supplied, the ethanol productivity was significantly enhanced as compared to the productivity of the culture without any air supplement. It was also found that the oxygen supplement improved cell viability considerably as well as the ethanol tolerance level of yeast. As the air supply rate was increased, from 0 to 11 mL air/L/h while maintaining a constant dilution rate at about 0.06 h(-1), the cell concentration increased from 2.3 to 8.2 g/L and the ethanol productivity increased from 1.7 to 4.1 g ethanol/L/h, although the specific ethanol production rate decreased slightly from 0.75 to 0.5 g ethanol/g cell/h. The ethanol yield was slightly improved also with an increase in air supply rate, from about 0.37 to 0.45 ethanol/g glucose. The maintenance coefficient increased by only a small amount with the air supplement. This kind of air supplement technique may very well prove to be of practical importance to a development of a highly productive ethanol fermentation process system especially as a combined system with a high density cell culture technique.

  7. Comparative feeding kinematics and performance of odontocetes: belugas, Pacific white-sided dolphins and long-finned pilot whales.

    PubMed

    Kane, E A; Marshall, C D

    2009-12-01

    Cetaceans are thought to display a diversity of feeding modes that are often described as convergent with other more basal aquatic vertebrates (i.e. actinopterygians). However, the biomechanics of feeding in cetaceans has been relatively ignored by functional biologists. This study investigated the feeding behavior, kinematics and pressure generation of three odontocetes with varying feeding modes (belugas, Delphinapterus leucas; Pacific white-sided dolphins, Lagenorhynchus obliquidens; and long-finned pilot whales, Globicephala melas). Four feeding phases were recognized in all odontocetes: (I) preparatory, (II) jaw opening, (III) gular depression, and (IV) jaw closing. Belugas relied on a feeding mode that was composed of discrete ram and suction components. Pacific white-sided dolphins fed using ram, with some suction for compensation or manipulation of prey. Pilot whales were kinematically similar to belugas but relied on a combination of ram and suction that was less discrete than belugas. Belugas were able to purse the anterior lips to occlude lateral gape and form a small, circular anterior aperture that is convergent with feeding behaviors observed in more basal vertebrates. Suction generation in odontocetes is a function of hyolingual displacement and rapid jaw opening, and is likely to be significantly enhanced by lip pursing behaviors. Some degree of subambient pressure was measured in all species, with belugas reaching 126 kPa. Functional variations of suction generation during feeding demonstrate a wider diversity of feeding behaviors in odontocetes than previously thought. However, odontocete suction generation is convergent with that of more basal aquatic vertebrates.

  8. Impact of the electric compressor for automotive air conditioning system on fuel consumption and performance analysis

    NASA Astrophysics Data System (ADS)

    Zulkifli, A. A.; Dahlan, A. A.; Zulkifli, A. H.; Nasution, H.; Aziz, A. A.; Perang, M. R. M.; Jamil, H. M.; Misseri, M. N.

    2015-12-01

    Air conditioning system is the biggest auxiliary load in a vehicle where the compressor consumed the largest. Problem with conventional compressor is the cooling capacity cannot be control directly to fulfill the demand of thermal load inside vehicle cabin. This study is conducted experimentally to analyze the difference of fuel usage and air conditioning performance between conventional compressor and electric compressor of the air conditioning system in automobile. The electric compressor is powered by the car battery in non-electric vehicle which the alternator will recharge the battery. The car is setup on a roller dynamometer and the vehicle speed is varied at 0, 30, 60, 90 and 110 km/h at cabin temperature of 25°C and internal heat load of 100 and 400 Watt. The results shows electric compressor has better fuel consumption and coefficient of performance compared to the conventional compressor.

  9. Experimental study of heat transfer and thermal performance with longitudinal fins of solar air heater

    PubMed Central

    Chabane, Foued; Moummi, Noureddine; Benramache, Said

    2013-01-01

    The thermal performance of a single pass solar air heater with five fins attached was investigated experimentally. Longitudinal fins were used inferior the absorber plate to increase the heat exchange and render the flow fluid in the channel uniform. The effect of mass flow rate of air on the outlet temperature, the heat transfer in the thickness of the solar collector, and the thermal efficiency were studied. Experiments were performed for two air mass flow rates of 0.012 and 0.016 kg s−1. Moreover, the maximum efficiency values obtained for the 0.012 and 0.016 kg s−1 with and without fins were 40.02%, 51.50% and 34.92%, 43.94%, respectively. A comparison of the results of the mass flow rates by solar collector with and without fins shows a substantial enhancement in the thermal efficiency. PMID:25685486

  10. Experimental study of heat transfer and thermal performance with longitudinal fins of solar air heater.

    PubMed

    Chabane, Foued; Moummi, Noureddine; Benramache, Said

    2014-03-01

    The thermal performance of a single pass solar air heater with five fins attached was investigated experimentally. Longitudinal fins were used inferior the absorber plate to increase the heat exchange and render the flow fluid in the channel uniform. The effect of mass flow rate of air on the outlet temperature, the heat transfer in the thickness of the solar collector, and the thermal efficiency were studied. Experiments were performed for two air mass flow rates of 0.012 and 0.016 kg s(-1). Moreover, the maximum efficiency values obtained for the 0.012 and 0.016 kg s(-1) with and without fins were 40.02%, 51.50% and 34.92%, 43.94%, respectively. A comparison of the results of the mass flow rates by solar collector with and without fins shows a substantial enhancement in the thermal efficiency.

  11. Performance of Introducing Outdoor Cold Air for Cooling a Plant Production System with Artificial Light.

    PubMed

    Wang, Jun; Tong, Yuxin; Yang, Qichang; Xin, Min

    2016-01-01

    The commercial use of a plant production system with artificial light (PPAL) is limited by its high initial construction and operation costs. The electric-energy consumed by heat pumps, applied mainly for cooling, accounts for 15-35% of the total electric-energy used in a PPAL. To reduce the electric-energy consumption, an air exchanger with low capacity (180 W) was used for cooling by introducing outdoor cold air. In this experiment, the indoor air temperature in two PPALs (floor area: 6.2 m(2) each) was maintained at 25 and 20°C during photoperiod and dark period, respectively, for lettuce production. A null CO2 balance enrichment method was used in both PPALs. In one PPAL (PPALe), an air exchanger (air flow rate: 250 m(3)·h(-1)) was used along with a heat pump (cooling capacity: 3.2 kW) to maintain the indoor air temperature at the set-point. The other PPAL (PPALc) with only a heat pump (cooling capacity: 3.2 kW) was used for reference. Effects of introducing outdoor cold air on energy use efficiency, coefficient of performance (COP), electric-energy consumption for cooling and growth of lettuce were investigated. The results show that: when the air temperature difference between indoor and outdoor ranged from 20.2 to 30.0°C: (1) the average energy use efficiency of the air exchanger was 2.8 and 3.4 times greater than the COP of the heat pumps in the PPALe and PPALc, respectively; (2) hourly electric-energy consumption for cooling in the PPALe reduced by 15.8-73.7% compared with that in the PPALc; (3) daily supply of CO2 in the PPALe reduced from 0.15 to 0.04 kg compared with that in the PPALc with the outdoor air temperature ranging from -5.6 to 2.7°C; (4) no significant difference in lettuce growth was observed in both PPALs. The results indicate that using air exchanger to introduce outdoor cold air should be considered as an effective way to reduce electric-energy consumption for cooling with little effects on plant growth in a PPAL.

  12. Performance of Introducing Outdoor Cold Air for Cooling a Plant Production System with Artificial Light

    PubMed Central

    Wang, Jun; Tong, Yuxin; Yang, Qichang; Xin, Min

    2016-01-01

    The commercial use of a plant production system with artificial light (PPAL) is limited by its high initial construction and operation costs. The electric-energy consumed by heat pumps, applied mainly for cooling, accounts for 15–35% of the total electric-energy used in a PPAL. To reduce the electric-energy consumption, an air exchanger with low capacity (180 W) was used for cooling by introducing outdoor cold air. In this experiment, the indoor air temperature in two PPALs (floor area: 6.2 m2 each) was maintained at 25 and 20°C during photoperiod and dark period, respectively, for lettuce production. A null CO2 balance enrichment method was used in both PPALs. In one PPAL (PPALe), an air exchanger (air flow rate: 250 m3·h−1) was used along with a heat pump (cooling capacity: 3.2 kW) to maintain the indoor air temperature at the set-point. The other PPAL (PPALc) with only a heat pump (cooling capacity: 3.2 kW) was used for reference. Effects of introducing outdoor cold air on energy use efficiency, coefficient of performance (COP), electric-energy consumption for cooling and growth of lettuce were investigated. The results show that: when the air temperature difference between indoor and outdoor ranged from 20.2 to 30.0°C: (1) the average energy use efficiency of the air exchanger was 2.8 and 3.4 times greater than the COP of the heat pumps in the PPALe and PPALc, respectively; (2) hourly electric-energy consumption for cooling in the PPALe reduced by 15.8–73.7% compared with that in the PPALc; (3) daily supply of CO2 in the PPALe reduced from 0.15 to 0.04 kg compared with that in the PPALc with the outdoor air temperature ranging from −5.6 to 2.7°C; (4) no significant difference in lettuce growth was observed in both PPALs. The results indicate that using air exchanger to introduce outdoor cold air should be considered as an effective way to reduce electric-energy consumption for cooling with little effects on plant growth in a PPAL. PMID:27066012

  13. Comparative study of solar air heater performance with various shapes and configurations of obstacles

    NASA Astrophysics Data System (ADS)

    Kulkarni, Kishor; Kim, Kwang-Yong

    2016-12-01

    An investigation is performed to find an optimum shape of obstacles attached to a solar air heater using three-dimensional Reynolds-averaged Navier-Stokes analyses of heat transfer and fluid flow. The Reynolds number, which is based on the hydraulic diameter of the channel, is in the range of 6800-10,000. The Nusselt number and friction factor are used to measure the thermal and aerodynamic performances of the solar air heater, respectively. Four different obstacle shapes (U-shaped, rectangular, trapezoidal, and pentagonal) and three arrangements of obstacles were tested to determine their effects on performance of the solar air heater. The results show that the performance factor (defined by a ratio of thermal to aerodynamic performance) was above unity for all the cases tested, and the pentagonal obstacle shape indicates the highest performance regardless of the Reynolds number. Detailed analyses of the thermal and flow fields are performed in order to obtain a better understanding of the heat transfer characteristics.

  14. Performance and cycle life of carbon- and conductive-based air electrodes for rechargeable Zn-air battery applications

    NASA Astrophysics Data System (ADS)

    Chellapandi Velraj, Samgopiraj

    The development of high-performance, cyclically stable bifunctional air electrodes are critical to the commercial deployment of rechargeable Zn-air batteries. The carbon material predominantly used as support material in the air electrodes due to its higher surface area and good electrical conductivity suffers from corrosion at high oxygen evolution overpotentials. This study addresses the carbon corrosion issues and suggests alternate materials to replace the carbon as support in the air electrode. In this study, Sm0.5Sr0.5CoO3-delta with good electrochemical performance and cyclic lifetime was identified as an alternative catalyst material to the commonly used La0.4Ca 0.6CoO3 catalyst for the carbon-based bifunctional electrodes. Also, a comprehensive study on the effects of catalyst morphology, testing conditions on the cycle life as well as the relevant degradation mechanism for the carbon-based electrode was conducted in this dissertation. The cyclic life of the carbon-based electrodes was strongly dependent on the carbon support material, while the degradation mechanisms were entirely controlled by the catalyst particle size/morphology. Some testing conditions like resting time and electrolyte concentration did not change the cyclic life or degradation mechanism of the carbon-based electrode. The current density used for cyclic testing was found to dictate the degradation mechanism leading to the electrode failure. An alternate way to circumvent the carbon corrosion is to replace the carbon support with a suitable electrically-conductive ceramic material. In this dissertation, LaNi0.9Mn0.1O3, LaNi 0.8Co0.2O3, and NiCo2O4 were synthesized and evaluated as prospective support materials due to their good electrical conductivity and their ability to act as the catalyst needed for the bifunctional electrode. The carbon-free electrodes had remarkably higher catalytic activity for oxygen evolution reaction (OER) when compared to the carbon-based electrode. However

  15. Swirl-can combustor performance to near-stoichiometric fuel-air ratio

    NASA Technical Reports Server (NTRS)

    Diehl, L. A.; Biaglow, J. A.

    1976-01-01

    Emissions and performance characteristics were determined for full-annulus swirl-can modular combustors operated to near stoichiometric fuel air ratios. The purposes of the tests were to obtain stoichiometric data at inlet air temperatures up to 894 K and to determine the effect of module number by investigating 120 and 72 module swirl-can combustors. The maximum average exit temperature obtained with the 120-module swirl-can combustor was 2465 K with a combustion efficiency of 95 percent at an inlet-air temperature of 894 K. The 72-module swirl-can combustor reached a maximum average exit temperature of 2306 K with a combustion efficiency of 92 percent at an inlet air temperature of 894 K. At a constant inlet air temperature, maximum oxides of nitrogen emission index values occurred at a fuel-air ratio of 0.037 for the 72-module design and 0.044 for the 120-module design. The combustor average exit temperature and combustion efficiency were calculated from emissions measurements. The measured emissions included carbon monoxide, unburned hydrocarbons, oxides of nitrogen, and smoke.

  16. Replacement Air Group Performance as a Criterion for Naval Aviation Training.

    ERIC Educational Resources Information Center

    Bale, Ronald M.; And Others

    The current criterion for prediction of performance of student naval aviators is the dichotomy of success versus failure in undergraduate flight training. This criterion has enabled the naval air training command to make reasonable estimates of the probability of an applicant or student completing flight training. However, a costly attrition…

  17. 33 CFR 165.1319 - Safety Zone Regulations, Seafair Blue Angels Air Show Performance, Seattle, WA.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Safety Zone Regulations, Seafair... Thirteenth Coast Guard District § 165.1319 Safety Zone Regulations, Seafair Blue Angels Air Show Performance... Federal Register. (b) Location. The following is a safety zone: All waters of Lake Washington,...

  18. Analytical predictions of liquid and air photovoltaic/thermal, flat-plate collector performance

    SciTech Connect

    Raghuraman, P.

    1981-11-01

    Two separate one-dimensional analyses have been developed for the prediction of the thermal and electrical performance of both liquid and air flat-plate, photovoltaic/thermal (PV/T) collectors. The results of the analyses are compared with test measurements, and therefrom design recommendations are made to maximize the total energy extracted from the collectors. 16 refs.

  19. 38 CFR 3.7 - Individuals and groups considered to have performed active military, naval, or air service.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... considered to have performed active military, naval, or air service. 3.7 Section 3.7 Pensions, Bonuses, and... Indemnity Compensation General § 3.7 Individuals and groups considered to have performed active military, naval, or air service. The following individuals and groups are considered to have performed...

  20. 38 CFR 3.7 - Individuals and groups considered to have performed active military, naval, or air service.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... considered to have performed active military, naval, or air service. 3.7 Section 3.7 Pensions, Bonuses, and... Indemnity Compensation General § 3.7 Individuals and groups considered to have performed active military, naval, or air service. The following individuals and groups are considered to have performed...

  1. 38 CFR 3.7 - Individuals and groups considered to have performed active military, naval, or air service.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... considered to have performed active military, naval, or air service. 3.7 Section 3.7 Pensions, Bonuses, and... Indemnity Compensation General § 3.7 Individuals and groups considered to have performed active military, naval, or air service. The following individuals and groups are considered to have performed...

  2. 38 CFR 3.7 - Individuals and groups considered to have performed active military, naval, or air service.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... considered to have performed active military, naval, or air service. 3.7 Section 3.7 Pensions, Bonuses, and... Indemnity Compensation General § 3.7 Individuals and groups considered to have performed active military, naval, or air service. The following individuals and groups are considered to have performed...

  3. Differential performance of Sitobion avenae populations from both sides of the Qinling Mountains under common garden conditions.

    PubMed

    Huang, Xianliang; Liu, Deguang; Gao, Suxia; Chen, Hui

    2013-12-01

    Sitobion avenae (F.) is a cosmopolitan cereal pest, but geographic barriers like the Qinling Mountains in the Shaanxi Province of China may lead to isolation among its populations, thus causing allopatric speciation. We sampled S. avenae populations from areas north (mean annual temperature, ≍9°C) and south (mean annual temperature, ≍14°C) of the Qinling Mountains, and tested them at 20°C in common garden experiments. The results showed that northern populations had reduced developmental time for first-instar nymphs but prolonged for third- and fourth-instar nymphs compared with southern populations. The postreproductive time and total lifespan of adults from southern populations were longer than those from northern populations, but no significant differences were found in reproductive time or age at first reproduction. Southern populations showed higher lifetime and daily fecundities than northern ones. Significant differences were found in correlation of life-history traits between northern and southern populations. Principal component analyses (PCAs) of S. avenae's vital life-history traits showed separation of populations from three southern locations, indicating their local adaptation. The clustering patterns generated by PCA also showed divergence between northern and southern populations. Alatae of S. avenae seemed to be able to disperse across the Qinling Mountains, which was indicated by the clustering together of some individuals from one side of the mountains with those from the other side. The impacts of the Qinling Mountains on the divergence and gene flow among S. avenae populations, as well as the potential of allopatric speciation for this species, are discussed.

  4. 2010-2011 Performance of the AirNow Satellite Data Processor

    NASA Astrophysics Data System (ADS)

    Pasch, A. N.; DeWinter, J. L.; Haderman, M. D.; van Donkelaar, A.; Martin, R. V.; Szykman, J.; White, J. E.; Dickerson, P.; Zahn, P. H.; Dye, T. S.

    2012-12-01

    The U.S. Environmental Protection Agency's (EPA) AirNow program provides maps of real time hourly Air Quality Index (AQI) conditions and daily AQI forecasts nationwide (http://www.airnow.gov). The public uses these maps to make health-based decisions. The usefulness of the AirNow air quality maps depends on the accuracy and spatial coverage of air quality measurements. Currently, the maps use only ground-based measurements, which have significant gaps in coverage in some parts of the United States. As a result, contoured AQI levels have high uncertainty in regions far from monitors. To improve the usefulness of air quality maps, scientists at EPA, Dalhousie University, and Sonoma Technology, Inc. have been working in collaboration with the National Aeronautics and Space Administration (NASA) and the National Oceanic and Atmospheric Administration (NOAA) to incorporate satellite-estimated surface PM2.5 concentrations into the maps via the AirNow Satellite Data Processor (ASDP). These satellite estimates are derived using NASA/NOAA satellite aerosol optical depth (AOD) retrievals and GEOS-Chem modeled ratios of surface PM2.5 concentrations to AOD. GEOS-Chem is a three-dimensional chemical transport model for atmospheric composition driven by meteorological input from the Goddard Earth Observing System (GOES). The ASDP can fuse multiple PM2.5 concentration data sets to generate AQI maps with improved spatial coverage. The goal of ASDP is to provide more detailed AQI information in monitor-sparse locations and augment monitor-dense locations with more information. We will present a statistical analysis for 2010-2011 of the ASDP predictions of PM2.5 focusing on performance at validation sites. In addition, we will present several case studies evaluating the ASDP's performance for multiple regions and seasons, focusing specifically on days when large spatial gradients in AQI and wildfire smoke impact were observed.

  5. Indoor Air Quality in 24 California Residences Designed as High-Performance Homes

    SciTech Connect

    Less, Brennan; Mullen, Nasim; Singer, Brett; Walker, Iain

    2015-07-01

    Today’s high performance green homes are reaching previously unheard of levels of airtightness and are using new materials, technologies and strategies, whose impacts on Indoor Air Quality (IAQ) cannot be fully anticipated from prior studies. This research study used pollutant measurements, home inspections, diagnostic testing and occupant surveys to assess IAQ in 24 new or deeply retrofitted homes designed to be high performance green buildings in California.

  6. Effect of High Z material on the performance of an air-breathing laser ablation thruster

    NASA Astrophysics Data System (ADS)

    Shimamura, Kohei; Kiyono, Inoru; Yokota, Ippei; Ozaki, Naoto; Yokota, Shigeru

    2016-09-01

    A Laser propulsion, such as a Lightcraft, is a candidate for the low cost transportation system between the ground to space instead of the chemical rocket. Using the shock wave induced by focusing laser beam on the ablator in air, the huge fuel is unnecessary to generate the thrust. In this study, the high-Z material was doped into the polystyrene to emphasize the ionization effect in air. We evaluate the intensity of the bremsstrahlung radiation, the plasma parameter, and the thrust performance.

  7. Long term weathering effects on the thermal performance of the solaron (air) solar collector

    NASA Technical Reports Server (NTRS)

    1979-01-01

    The test procedures and the results obtained during the evaluation test program on the Solaron Corporation air-type solar collector are presented. The tests were performed under simulated conditions, following long-term exposure to natural weathering conditions. The Solaron Model 2001, air-type solar collector has a gross area of 19 square feet and the weight is 160 pounds. The absorber plate is made of 24-gage steel, the coating is baked-on black paint, the cover consists of two sheets of 1/8-inch low-iron tempered glass, and the insulation is one thickness of 3 5/8-inch fiberglass batting.

  8. Performance of Silica Gel in the Role of Residual Air Drying

    NASA Technical Reports Server (NTRS)

    Jan, Darrell L.; Hogan, John A.; Koss, Brian; Palmer, Gary H.; Richardson, Justine; Linggi, Paul

    2014-01-01

    Removal of carbon dioxide (CO2) is a necessary step in air revitalization and is often accomplished with sorbent materials. Since moisture competes with CO2 in sorbent materials, it is necessary to remove the water first. This is typically accomplished in two stages: bulk removal and residual drying. Silica gel is used as the bulk drying material in the Carbon Dioxide Removal Assembly (CDRA) in operation on ISS. There has been some speculation that silica gel may also be capable of serving as the residual drying material. This paper will describe test apparatus and procedures for determining the performance of silica gel in residual air drying.

  9. "Meet Us at the Other Side of the River": Performance Venue and Community Education among Migrant Fishermen in Nigeria

    ERIC Educational Resources Information Center

    Nwadigwe, Charles E.

    2007-01-01

    The site of the performance is largely a cultural expression defining the physical surroundings and conditions in which the audience and performers interact. Similarly, the character of the theatrical occasion is often shaped by the place designated for the event. In contemporary practice and discourse, the concept of theatre has widened, giving…

  10. Effects of Automation Types on Air Traffic Controller Situation Awareness and Performance

    NASA Technical Reports Server (NTRS)

    Sethumadhavan, A.

    2009-01-01

    The Joint Planning and Development Office has proposed the introduction of automated systems to help air traffic controllers handle the increasing volume of air traffic in the next two decades (JPDO, 2007). Because fully automated systems leave operators out of the decision-making loop (e.g., Billings, 1991), it is important to determine the right level and type of automation that will keep air traffic controllers in the loop. This study examined the differences in the situation awareness (SA) and collision detection performance of individuals when they worked with information acquisition, information analysis, decision and action selection and action implementation automation to control air traffic (Parasuraman, Sheridan, & Wickens, 2000). When the automation was unreliable, the time taken to detect an upcoming collision was significantly longer for all the automation types compared with the information acquisition automation. This poor performance following automation failure was mediated by SA, with lower SA yielding poor performance. Thus, the costs associated with automation failure are greater when automation is applied to higher order stages of information processing. Results have practical implications for automation design and development of SA training programs.

  11. Design and performance of serial powered single-sided modules within an integrated stave assembly for the ATLAS tracker barrel upgrade

    NASA Astrophysics Data System (ADS)

    Affolder, A.; Carrol, J.; Greenall, A.; Wormald, M.

    2010-12-01

    The design and performance of prototype single-sided modules with ABCN-25 front-end chips and 10x10 cm2 Hamamatsu silicon strip sensors is presented. A low mass module assembly has been achieved by gluing a single-sided flex circuit, with read out chips, directly onto the sensor. The design exploits the embedded shunt regulation within the ABCN-25 providing for a distributed and scalable powered architecture. This allows for multiple modules to be linked together serially to form larger stave structures of up to 12 modules. The stave's digital I/O is realised as a multi-drop LVDS bus flex cable glued to the stave core assembly using a custom receiver/transmitter ASIC (BCC). The results of preliminary electrical tests with 4 module stavelets will be presented.

  12. Side-chain Engineering of Benzo[1,2-b:4,5-b’]dithiophene Core-structured Small Molecules for High-Performance Organic Solar Cells

    PubMed Central

    Yin, Xinxing; An, Qiaoshi; Yu, Jiangsheng; Guo, Fengning; Geng, Yongliang; Bian, Linyi; Xu, Zhongsheng; Zhou, Baojing; Xie, Linghai; Zhang, Fujun; Tang, Weihua

    2016-01-01

    Three novel small molecules have been developed by side-chain engineering on benzo[1,2-b:4,5-b’]dithiophene (BDT) core. The typical acceptor-donor-acceptor (A-D-A) structure is adopted with 4,8-functionalized BDT moieties as core, dioctylterthiophene as π bridge and 3-ethylrhodanine as electron-withdrawing end group. Side-chain engineering on BDT core exhibits small but measurable effect on the optoelectronic properties of small molecules. Theoretical simulation and X-ray diffraction study reveal the subtle tuning of interchain distance between conjugated backbones has large effect on the charge transport and thus the photovoltaic performance of these molecules. Bulk-heterojunction solar cells fabricated with a configuration of ITO/PEDOT:PSS/SM:PC71BM/PFN/Al exhibit a highest power conversion efficiency (PCE) of 6.99% after solvent vapor annealing. PMID:27140224

  13. Side-chain Engineering of Benzo[1,2-b:4,5-b']dithiophene Core-structured Small Molecules for High-Performance Organic Solar Cells.

    PubMed

    Yin, Xinxing; An, Qiaoshi; Yu, Jiangsheng; Guo, Fengning; Geng, Yongliang; Bian, Linyi; Xu, Zhongsheng; Zhou, Baojing; Xie, Linghai; Zhang, Fujun; Tang, Weihua

    2016-05-03

    Three novel small molecules have been developed by side-chain engineering on benzo[1,2-b:4,5-b']dithiophene (BDT) core. The typical acceptor-donor-acceptor (A-D-A) structure is adopted with 4,8-functionalized BDT moieties as core, dioctylterthiophene as π bridge and 3-ethylrhodanine as electron-withdrawing end group. Side-chain engineering on BDT core exhibits small but measurable effect on the optoelectronic properties of small molecules. Theoretical simulation and X-ray diffraction study reveal the subtle tuning of interchain distance between conjugated backbones has large effect on the charge transport and thus the photovoltaic performance of these molecules. Bulk-heterojunction solar cells fabricated with a configuration of ITO/PEDOT:PSS/SM:PC71BM/PFN/Al exhibit a highest power conversion efficiency (PCE) of 6.99% after solvent vapor annealing.

  14. Side-chain Engineering of Benzo[1,2-b:4,5-b’]dithiophene Core-structured Small Molecules for High-Performance Organic Solar Cells

    NASA Astrophysics Data System (ADS)

    Yin, Xinxing; An, Qiaoshi; Yu, Jiangsheng; Guo, Fengning; Geng, Yongliang; Bian, Linyi; Xu, Zhongsheng; Zhou, Baojing; Xie, Linghai; Zhang, Fujun; Tang, Weihua

    2016-05-01

    Three novel small molecules have been developed by side-chain engineering on benzo[1,2-b:4,5-b’]dithiophene (BDT) core. The typical acceptor-donor-acceptor (A-D-A) structure is adopted with 4,8-functionalized BDT moieties as core, dioctylterthiophene as π bridge and 3-ethylrhodanine as electron-withdrawing end group. Side-chain engineering on BDT core exhibits small but measurable effect on the optoelectronic properties of small molecules. Theoretical simulation and X-ray diffraction study reveal the subtle tuning of interchain distance between conjugated backbones has large effect on the charge transport and thus the photovoltaic performance of these molecules. Bulk-heterojunction solar cells fabricated with a configuration of ITO/PEDOT:PSS/SM:PC71BM/PFN/Al exhibit a highest power conversion efficiency (PCE) of 6.99% after solvent vapor annealing.

  15. Two Droplets Burning Side by Side

    NASA Technical Reports Server (NTRS)

    2003-01-01

    The Fiber-Supported Droplet Combustion (FSDC) experiment team got more than twice as many burns have been completed as were originally scheduled for STS-95. This image was taken July 12, 1997, MET:10/08:13 (approximate). As shown here, scientists were able to burn two droplets side by side, more closely mimicking behavior of burning fuel in an engine. This shows ignition of a single drop that subsequently burned while a fan blew through the chamber, giving the scientists data on burning with convection, but no buoyancy -- an important distinction when you're trying to solve a problem by breaking it into parts. FSDC-2 studied fundamental phenomena related to liquid fuel droplet combustion in air. Pure fuels and mixtures of fuels were burned as isolated single and dual droplets with and without forced air convection. The FSDC guest investigator was Forman Williams, University of California, San Diego. The experiment was part of the space research investigations conducted during the Microgravity Science Laboratory-1R mission (STS-94, July 1-17 1997). Advanced combustion experiments will be a part of investigations plarned for the International Space Station. (1.1 MB, 11-second MPEG, screen 320 x 240 pixels; downlinked video, higher quality not available) A still JPG composite of this movie is available at http://mix.msfc.nasa.gov/ABSTRACTS/MSFC-0300176.html.

  16. Finger Flexor Force Influences Performance in Senior Male Air Pistol Olympic Shooting.

    PubMed

    Mon, Daniel; Zakynthinaki, María S; Cordente, Carlos A; Antón, Antonio J Monroy; Rodríguez, Bárbara Rodríguez; Jiménez, David López

    2015-01-01

    The ability to stabilize the gun is crucial for performance in Olympic pistol shooting and is thought to be related to the shooters muscular strength. The present study examines the relation between performance and finger flexor force as well as shoulder abduction isometric force in senior male air pistol shooting. 46 Spanish national level shooters served as test subjects of the study. Two maximal force tests were carried out recording handgrip and deltoid force data under competition conditions, during the official training time at national Spanish championships. Performance was measured as the total score of 60 shots at competition. Linear regressions were calculated to examine the relations between performance and peak and average finger flexor forces, peak and average finger flexor forces relative to the BMI, peak and average shoulder abduction isometric forces, peak shoulder abduction isometric force relative to the BMI. The connection between performance and other variables such as age, weight, height, BMI, experience in years and training hours per week was also analyzed. Significant correlations were found between performance at competition and average and peak finger flexor forces. For the rest of the force variables no significant correlations were found. Significant correlations were also found between performance at competition and experience as well as training hours. No significant correlations were found between performance and age, weight, height or BMI. The study concludes that hand grip strength training programs are necessary for performance in air pistol shooting.

  17. Finger Flexor Force Influences Performance in Senior Male Air Pistol Olympic Shooting

    PubMed Central

    Mon, Daniel; Zakynthinaki, María S.; Cordente, Carlos A.; Antón, Antonio J. Monroy; Rodríguez, Bárbara Rodríguez; Jiménez, David López

    2015-01-01

    The ability to stabilize the gun is crucial for performance in Olympic pistol shooting and is thought to be related to the shooters muscular strength. The present study examines the relation between performance and finger flexor force as well as shoulder abduction isometric force in senior male air pistol shooting. 46 Spanish national level shooters served as test subjects of the study. Two maximal force tests were carried out recording handgrip and deltoid force data under competition conditions, during the official training time at national Spanish championships. Performance was measured as the total score of 60 shots at competition. Linear regressions were calculated to examine the relations between performance and peak and average finger flexor forces, peak and average finger flexor forces relative to the BMI, peak and average shoulder abduction isometric forces, peak shoulder abduction isometric force relative to the BMI. The connection between performance and other variables such as age, weight, height, BMI, experience in years and training hours per week was also analyzed. Significant correlations were found between performance at competition and average and peak finger flexor forces. For the rest of the force variables no significant correlations were found. Significant correlations were also found between performance at competition and experience as well as training hours. No significant correlations were found between performance and age, weight, height or BMI. The study concludes that hand grip strength training programs are necessary for performance in air pistol shooting. PMID:26121145

  18. The 727 airplane side inlet low-speed performance confirmation model test for refanned JT8D engines

    NASA Technical Reports Server (NTRS)

    Schuehle, A. L.

    1974-01-01

    The results of a low-speed wind tunnel test of a 0.3 scale model 727 airplane side inlet for JT8D-100 engines are presented. The objectives of the test were to develop lines for a full-scale flightworthy inlet, to evaluate inlet total pressure recovery and steady-state total pressure distortion, and to obtain model-scale distortion data which can be used in the assessment of the compatibility of the inlet with the JT8D-100 series engines. A secondary objective was to obtain internal/external cowl static pressures for the determination of nacelle loads. Two basic inlet models were tested at static, forward speed, angle-of-attack (inflow angle), and cross-wind conditions. One model was with and one without an acoustic ring. Two modifications to the models were also tested, one with the ring closer to the inlet throat and one with a larger lip. Test measurements consisted of inlet surface static pressure, engine face total pressure, inlet airflow, tunnel total pressure, tunnel total temperature and tunnel velocity. Total pressure traverses were taken directly behind the ring and strut. No dynamic measurements were taken.

  19. Is Mixed Practice More Effective than Physical Practice Alone for the Acquisition of Non-dominant Side Kicking Performance?

    PubMed Central

    Steel, Kylie A.; Ellem, Eathan

    2016-01-01

    Perceiving and executing unfamiliar movements, such as left handed/footed movement skills in sports, places additional demands on the perceptual-cognitive system of players that may increase errors. The video self-modeling (VSM) method may provide an accessible solution to this issue, therefore the purpose of this study was to investigate the effect of the VSM method on the improvement of a non-preferred side kicking task. N = 28 participants engaged in one of three conditions; Mirror reversed/ physical practice (PP), best-of/ PP, or physical practice only. Though not significant, data analysis indicated improved kicking accuracy for all groups, with VSM groups showing the most improvement. However, qualitative data revealed the “best-of” group demonstrated more positive views toward their progress compared to other groups, and both VSM groups were more likely to attend to movement cues than target based cues. These trends may suggest merit for the use of VSM techniques, though its application and the source of mechanistic factors warrant further investigation. PMID:27826280

  20. Energy Performance Comparison of Heating and Air Conditioning Systems for Multi-Family Residential Buildings

    SciTech Connect

    Wang, Weimin; Zhang, Jian; Jiang, Wei; Liu, Bing

    2011-07-31

    The type of heating, ventilation and air conditioning (HVAC) system has a large impact on the heating and cooling energy consumption in multifamily residential buildings. This paper compares the energy performance of three HVAC systems: a direct expansion (DX) split system, a split air source heat pump (ASHP) system, and a closed-loop water source heat pump (WSHP) system with a boiler and an evaporative fluid cooler as the central heating and cooling source. All three systems use gas furnace for heating or heating backup. The comparison is made in a number of scenarios including different climate conditions, system operation schemes and applicable building codes. It is found that with the minimum code-compliant equipment efficiency, ASHP performs the best among all scenarios except in extremely code climates. WSHP tends to perform better than the split DX system in cold climates but worse in hot climates.

  1. Environmental performance of air staged combustor with flue gas recirculation to burn coal/biomass

    SciTech Connect

    Anuar, S.H.; Keener, H.M.

    1995-12-31

    The environmental and thermal performance of a 1.07 m diameter, 440 kW atmospheric fluidized bed combustor operated at 700{degrees}C-920{degrees}C and burning coal was studied. Flue gas recirculation was incorporated to enhance the thermal performance and air staging was used to control emissions of SO{sub 2}, CO, NO{sub x} and N{sub 2}O. Studies focused on the effect of excess air, firing rate, and use of sorbent on system performance. The recirculation-staging mode with limestone had the highest thermal efficiency (0.67) using the firing equation. Emission data showed that flue gas recirculation (ratio of 0.7) significantly reduced NO{sub x} emissions; and that use of limestone sorbent at a Ca/S ratio of 3 reduced SO{sub 2} emissions by 64% to approximately 0.310 g/MJ.

  2. The Impact of Trajectory Prediction Uncertainty on Air Traffic Controller Performance and Acceptability

    NASA Technical Reports Server (NTRS)

    Mercer, Joey S.; Bienert, Nancy; Gomez, Ashley; Hunt, Sarah; Kraut, Joshua; Martin, Lynne; Morey, Susan; Green, Steven M.; Prevot, Thomas; Wu, Minghong G.

    2013-01-01

    A Human-In-The-Loop air traffic control simulation investigated the impact of uncertainties in trajectory predictions on NextGen Trajectory-Based Operations concepts, seeking to understand when the automation would become unacceptable to controllers or when performance targets could no longer be met. Retired air traffic controllers staffed two en route transition sectors, delivering arrival traffic to the northwest corner-post of Atlanta approach control under time-based metering operations. Using trajectory-based decision-support tools, the participants worked the traffic under varying levels of wind forecast error and aircraft performance model error, impacting the ground automations ability to make accurate predictions. Results suggest that the controllers were able to maintain high levels of performance, despite even the highest levels of trajectory prediction errors.

  3. The Thermal Performance and Air Leakage Characteristics of Six Log Homes in Idaho.

    SciTech Connect

    Roos, Carolyn; Eklund, Ken; Baylon, David

    1993-08-01

    The thermal performance and air leakage characteristics of four electrically heated log houses located in Idaho are summarized. The air leakage and construction characteristics of two additional log homes are also examined. The energy consumption of the four homes was submetered at weekly reporting intervals for up to 16 months. Blower door tests and site audits were performed. In addition, conditions at two of these homes, including heat flux through the log walls, indoor and outdoor temperatures, solar flux and envelope tightness, were measured in detail over several days during winter conditions. The energy use and thermal performance of these two homes were then modeled using SUNCODE-PC, an hourly thermal simulation program employing a finite difference technique.

  4. Experimental performance study of a proposed desiccant based air conditioning system.

    PubMed

    Bassuoni, M M

    2014-01-01

    An experimental investigation on the performance of a proposed hybrid desiccant based air conditioning system referred as HDBAC is introduced in this paper. HDBAC is mainly consisted of a liquid desiccant dehumidification unit integrated with a vapor compression system (VCS). The VCS unit has a cooling capacity of 5.27 kW and uses 134a as refrigerant. Calcium chloride (CaCl2) solution is used as the working desiccant material. HDBAC system is used to serve low sensible heat factor applications. The effect of different parameters such as, process air flow rate, desiccant solution flow rate, evaporator box and condenser box solution temperatures, strong solution concentration and regeneration temperature on the performance of the system is studied. The performance of the system is evaluated using some parameters such as: the coefficient of performance (COPa), specific moisture removal and energy saving percentage. A remarkable increase of about 54% in the coefficient of performance of the proposed system over VCS with reheat is achieved. A maximum overall energy saving of about 46% is observed which emphasizes the use of the proposed system as an energy efficient air conditioning system.

  5. Experimental performance study of a proposed desiccant based air conditioning system

    PubMed Central

    Bassuoni, M.M.

    2013-01-01

    An experimental investigation on the performance of a proposed hybrid desiccant based air conditioning system referred as HDBAC is introduced in this paper. HDBAC is mainly consisted of a liquid desiccant dehumidification unit integrated with a vapor compression system (VCS). The VCS unit has a cooling capacity of 5.27 kW and uses 134a as refrigerant. Calcium chloride (CaCl2) solution is used as the working desiccant material. HDBAC system is used to serve low sensible heat factor applications. The effect of different parameters such as, process air flow rate, desiccant solution flow rate, evaporator box and condenser box solution temperatures, strong solution concentration and regeneration temperature on the performance of the system is studied. The performance of the system is evaluated using some parameters such as: the coefficient of performance (COPa), specific moisture removal and energy saving percentage. A remarkable increase of about 54% in the coefficient of performance of the proposed system over VCS with reheat is achieved. A maximum overall energy saving of about 46% is observed which emphasizes the use of the proposed system as an energy efficient air conditioning system. PMID:25685475

  6. Effects of simulated domestic and international air travel on sleep, performance, and recovery for team sports.

    PubMed

    Fowler, P; Duffield, R; Vaile, J

    2015-06-01

    The present study examined effects of simulated air travel on physical performance. In a randomized crossover design, 10 physically active males completed a simulated 5-h domestic flight (DOM), 24-h simulated international travel (INT), and a control trial (CON). The mild hypoxia, seating arrangements, and activity levels typically encountered during air travel were simulated in a normobaric, hypoxic altitude room. Physical performance was assessed in the afternoon of the day before (D - 1 PM) and in the morning (D + 1 AM) and afternoon (D + 1 PM) of the day following each trial. Mood states and physiological and perceptual responses to exercise were also examined at these time points, while sleep quantity and quality were monitored throughout each condition. Sleep quantity and quality were significantly reduced during INT compared with CON and DOM (P < 0.01). Yo-Yo Intermittent Recovery level 1 test performance was significantly reduced at D + 1 PM following INT compared with CON and DOM (P < 0.01), where performance remained unchanged (P > 0.05). Compared with baseline, physiological and perceptual responses to exercise, and mood states were exacerbated following the INT trial (P < 0.05). Attenuated intermittent-sprint performance following simulated international air travel may be due to sleep disruption during travel and the subsequent exacerbated physiological and perceptual markers of fatigue.

  7. Performance evaluation of household pyrolytic stove: Effect of outer air holes condition

    NASA Astrophysics Data System (ADS)

    Pradana, Yano Surya; Prasetya, Agus

    2017-03-01

    Renewable energy is the future energy for the substitution of the depleting fossil fuels. In Indonesia, biomass is one of promising renewable energy due to its abundant availability. Biomass can be converted into energy by thermochemical process, such as pyrolysis. In the implementation, pyrolysis can be applied in household cookstove, called pyrolytic stove. Pyrolytic stove will be proposed for people still cooking over an open biomass fire. This paper studied the pyrolysis of Indonesian teak using household pyrolytic stove. The effect of outer air holes on the performance of household pyrolytic stove was investigated. The increasing of cross section area of outer air holes effected on the higher of biomass combustion releasing energy for pyrolysis and cooking. Furthermore, the optimum outer air holes condition in the stove was fully open with the minimum of char product and the maximum of energy recovered for cooking.

  8. Performance evaluation of radiant cooling system integrated with air system under different operational strategies

    SciTech Connect

    Khan, Yasin; Khare, Vaibhav Rai; Mathur, Jyotirmay; Bhandari, Mahabir

    2015-03-26

    The paper describes a parametric study developed to estimate the energy savings potential of a radiant cooling system installed in a commercial building in India. The study is based on numerical modeling of a radiant cooling system installed in an Information Technology (IT) office building sited in the composite climate of Hyderabad. To evaluate thermal performance and energy consumption, simulations were carried out using the ANSYS FLUENT and EnergyPlus softwares, respectively. The building model was calibrated using the measured data for the installed radiant system. Then this calibrated model was used to simulate the energy consumption of a building using a conventional all-air system to determine the proportional energy savings. For proper handling of the latent load, a dedicated outside air system (DOAS) was used as an alternative to Fan Coil Unit (FCU). A comparison of energy consumption calculated that the radiant system was 17.5 % more efficient than a conventional all-air system and that a 30% savings was achieved by using a DOAS system compared with a conventional system. Computational Fluid Dynamics (CFD) simulation was performed to evaluate indoor air quality and thermal comfort. It was found that a radiant system offers more uniform temperatures, as well as a better mean air temperature range, than a conventional system. To further enhance the energy savings in the radiant system, different operational strategies were analyzed based on thermal analysis using EnergyPlus. Lastly, the energy savings achieved in this parametric run were more than 10% compared with a conventional all-air system.

  9. Performance evaluation of radiant cooling system integrated with air system under different operational strategies

    DOE PAGES

    Khan, Yasin; Khare, Vaibhav Rai; Mathur, Jyotirmay; ...

    2015-03-26

    The paper describes a parametric study developed to estimate the energy savings potential of a radiant cooling system installed in a commercial building in India. The study is based on numerical modeling of a radiant cooling system installed in an Information Technology (IT) office building sited in the composite climate of Hyderabad. To evaluate thermal performance and energy consumption, simulations were carried out using the ANSYS FLUENT and EnergyPlus softwares, respectively. The building model was calibrated using the measured data for the installed radiant system. Then this calibrated model was used to simulate the energy consumption of a building usingmore » a conventional all-air system to determine the proportional energy savings. For proper handling of the latent load, a dedicated outside air system (DOAS) was used as an alternative to Fan Coil Unit (FCU). A comparison of energy consumption calculated that the radiant system was 17.5 % more efficient than a conventional all-air system and that a 30% savings was achieved by using a DOAS system compared with a conventional system. Computational Fluid Dynamics (CFD) simulation was performed to evaluate indoor air quality and thermal comfort. It was found that a radiant system offers more uniform temperatures, as well as a better mean air temperature range, than a conventional system. To further enhance the energy savings in the radiant system, different operational strategies were analyzed based on thermal analysis using EnergyPlus. Lastly, the energy savings achieved in this parametric run were more than 10% compared with a conventional all-air system.« less

  10. Influence of air pressure on the performance of plasma synthetic jet actuator

    NASA Astrophysics Data System (ADS)

    Li, Yang; Jia, Min; Wu, Yun; Li, Ying-hong; Zong, Hao-hua; Song, Hui-min; Liang, Hua

    2016-09-01

    Plasma synthetic jet actuator (PSJA) has a wide application prospect in the high-speed flow control field for its high jet velocity. In this paper, the influence of the air pressure on the performance of a two-electrode PSJA is investigated by the schlieren method in a large range from 7 kPa to 100 kPa. The energy consumed by the PSJA is roughly the same for all the pressure levels. Traces of the precursor shock wave velocity and the jet front velocity vary a lot for different pressures. The precursor shock wave velocity first decreases gradually and then remains at 345 m/s as the air pressure increases. The peak jet front velocity always appears at the first appearance of a jet, and it decreases gradually with the increase of the air pressure. A maximum precursor shock wave velocity of 520 m/s and a maximum jet front velocity of 440 m/s are observed at the pressure of 7 kPa. The averaged jet velocity in one period ranges from 44 m/s to 54 m/s for all air pressures, and it drops with the rising of the air pressure. High velocities of the precursor shock wave and the jet front indicate that this type of PSJA can still be used to influence the high-speed flow field at 7 kPa. Project supported by the National Natural Science Foundation of China (Grant Nos. 51407197, 51522606, 51336011, 91541120, and 11472306).

  11. Performance of the AIRS Pulse Tube Coolers and Instrument—A First Year in Space

    NASA Astrophysics Data System (ADS)

    Ross, R. G.; Rodriguez, J. I.

    2004-06-01

    Launched on NASA's Aqua platform on May 4, 2002, JPL's Atmospheric Infrared Sounder (AIRS) instrument has completed a successful first year in space and captured a number of important lessons. AIRS is designed to make precision measurements of air temperature over the surface of the Earth and uses a redundant pair of TRW 55 K pulse tube cryocoolers to cool its sensitive IR focal plane. Soon after the instrument went cold, contamination of cryogenic surfaces led to increased cooler loads and the need for decontamination cycles. In addition, single event transients occurred while passing through the South Atlantic Anomaly (SAA) necessitating corrective actions. In November 2002 the fundamental operating strategy of the AIRS instrument was changed from the original strategy of running a single cooler and having the second cooler as a non-operating backup. Instead, based on a new system-level reliability analysis, both coolers began operation simultaneously. This change resolved the contamination and SAA driven interruptions and has enabled unprecedented levels of continuous science measurements. A review of the AIRS instrument cryogenic performance over the past year is presented including its contamination buildup and interrupt history. The reliability analysis conducted to justify two-cooler operation is also reviewed.

  12. Ground performance of air conditioning and water recycle system for a Space Plant Box.

    PubMed

    Tani, A; Okuma, T; Goto, E; Kitaya, Y; Saito, T; Takahashi, H

    2001-01-01

    Researchers from 5 Japanese universities have developed a plant growth facility (Space Plant Box) for seed to seed experiments under microgravity. The breadboard model of the Space Plant Box was fabricated by assembling subsystems developed for microgravity. The subsystems include air conditioning and water recycle system, air circulation system, water and nutrient delivery system, lighting system and plant monitoring system. The air conditioning and water recycle system is simply composed of a single heat exchanger, two fans and hydrophilic fibrous strings. The strings allow water movement from the cooler fin in the Cooling Box to root supporting materials in the Plant Growth Chamber driven by water potential deficit. Relative humidity in the Plant Growth Chamber can be changed over a wide range by controlling the ratio of latent heat exchange to sensible heat exchange on the cooling fin of the heat exchanger. The transpiration rate was successfully measured by circulating air inside the Plant Growth Chamber only. Most water was recycled and a small amount of water needed to be added from the outside. The simple, air conditioning and water recycle system for the Space Plant Box showed good performance through a barley (Hordeum vulgare L.) growth experiment.

  13. Data link air traffic control and flight deck environments: Experiment in flight crew performance

    NASA Technical Reports Server (NTRS)

    Lozito, Sandy; Mcgann, Alison; Corker, Kevin

    1993-01-01

    This report describes an experiment undertaken in a full mission simulation environment to investigate the performance impact of, and human/system response to, data-linked Air Traffic Control (ATC) and automated flight deck operations. Subjects were twenty pilots (ten crews) from a major United States air carrier. Crews flew the Advanced Concepts Flight Simulator (ACFS), a generic 'glass cockpit' simulator at NASA Ames. The method of data link used was similar to the data link implementation plans for a next-generation aircraft, and included the capability to review ATC messages and directly enter ATC clearance information into the aircraft systems. Each crew flew experimental scenarios, in which data reflecting communication timing, errors and clarifications, and procedures were collected. Results for errors and clarifications revealed an interaction between communication modality (voice v. data link) and communication type (air/ground v. intracrew). Results also revealed that voice crews initiated ATC contact significantly more than data link crews. It was also found that data link crews performed significantly more extraneous activities during the communication task than voice crews. Descriptive data from the use of the review menu indicate the pilot-not-flying accessing the review menu most often, and also suggest diffulty in accessing the target message within the review menu structure. The overall impact of communication modality upon air/ground communication and crew procedures is discussed.

  14. The Role of Radial Clearance on the Performance of Foil Air Bearings

    NASA Technical Reports Server (NTRS)

    Radil, Kevin; Howard, Samuel; Dykas, Brian

    2002-01-01

    Load capacity tests were conducted to determine how radial clearance variations affect the load capacity coefficient of foil air bearings. Two Generation III foil air bearings with the same design but possessing different initial radial clearances were tested at room temperature against an as-ground PS304 coated journal operating at 30,000 rpm. Increases in radial clearance were accomplished by reducing the journal's outside diameter via an in-place grinding system. From each load capacity test the bearing load capacity coefficient was calculated from the rule-of-thumb (ROT) model developed for foil air bearings. The test results indicate that, in terms of the load capacity coefficient, radial clearance has a direct impact on the performance of the foil air bearing. Each test bearing exhibited an optimum radial clearance that resulted in a maximum load capacity coefficient. Relative to this optimum value are two separate operating regimes that are governed by different modes of failure. Bearings operating with radial clearances less than the optimum exhibit load capacity coefficients that are a strong function of radial clearance and are prone to a thermal runaway failure mechanism and bearing seizure. Conversely, a bearing operating with a radial clearance twice the optimum suffered only a 20 percent decline in its maximum load capacity coefficient and did not experience any thermal management problems. However, it is unknown to what degree these changes in radial clearance had on other performance parameters, such as the stiffness and damping properties of the bearings.

  15. Superiority of branched side chains in spontaneous nanowire formation: exemplified by poly(3-2-methylbutylthiophene) for high-performance solar cells.

    PubMed

    Chen, Hsieh-Chih; Wu, I-Che; Hung, Jui-Hsiang; Chen, Fu-Je; Chen, I-Wen P; Peng, Yung-Kang; Lin, Chao-Sung; Chen, Chun-Hsien; Sheng, Yu-Jane; Tsao, Heng-Kwong; Chou, Pi-Tai

    2011-04-18

    One-dimensional nanostructures containing heterojunctions by conjugated polymers, such as nanowires, are expected to greatly facilitate efficient charge transfer in bulk-heterojunction (BHJ) solar cells. Thus, a combined theoretical and experimental approach is pursued to explore spontaneous nanowire formation. A dissipative particle dynamics simulation is first performed to study the morphologies formed by rodlike polymers with various side-chain structures. The results surprisingly predict that conjugated polymers with branched side chains are well suited to form thermodynamically stable nanowires. Proof of this concept is provided via the design and synthesis of a branched polymer of regioregular poly(3-2-methylbutylthiophene) (P3MBT), which successfully demonstrates highly dense nanowire formation free from any stringent conditions and stratagies. In BHJ solar cells fabricated using a blend of P3MBT and [6,6]-phenyl-C71-butyric acid methyl ester (PC(71) BM), P3MBT polymers are self-organized into highly crystalline nanowires with a d(100) spacing of 13.30 Å. The hole mobility of the P3MBT:PC(71) BM (1:0.5 by weight) blend film reaches 3.83 × 10(-4) cm(2) V(-1) s(-1) , and the maximum incident photon-to-current efficiency reaches 68%. The results unambiguously prove the spontaneous formation of nanowires using solution-processable conjugated polymers with branched alkyl side chains in BHJ solar cells.

  16. Development of cold seawater air conditioning systems for application as a demand side management tool for Hawaii and other subtropical climates

    SciTech Connect

    Kaya, M.H.

    1996-10-01

    Because of the proximity to deep cold seawater for many coastal regions in Hawaii and the high demand for air conditioning in large buildings, seawater air conditioning (SWAC) is a major potential sustainable energy resource for Hawaii and other subtropical regions of the world. The basic concept of seawater air conditioning is the use deep cold seawater to cool the chilled water in one or more air conditioned buildings as opposed to using energy intensive refrigeration systems. The economic viability of the seawater air conditioning is determined by comparing the construction and operating costs of the seawater supply system to the construction and operating costs of conventional air conditioning systems. The State of Hawaii commissioned an analysis to identify the technical and economic opportunities and limitations in the use of SWAC in Hawaii. The result of this work is a feasibility analysis of SWAC systems in the state and the potential associated energy savings. The study looked at the prospects of installing such a system at a major new resort development on Oahu called West Beach.

  17. 38 CFR 3.7 - Individuals and groups considered to have performed active military, naval, or air service.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... considered to have performed active military, naval, or air service. 3.7 Section 3.7 Pensions, Bonuses, and... Indemnity Compensation General § 3.7 Individuals and groups considered to have performed active military... military, naval, or air service: (a) Aerial transportation of mail (Pub. L. 140, 73d Congress). Persons...

  18. The Dark Side of Top Level Sport: An Autobiographic Study of Depressive Experiences in Elite Sport Performers.

    PubMed

    Newman, Hannah J H; Howells, Karen L; Fletcher, David

    2016-01-01

    The general and sport psychology research converge to point to a complex relationship between depressive experiences and human performance. The purpose of this study was to explore the depressive experiences of top level athletes and the relationship of such experiences with sport performance. Twelve autobiographies of elite athletes representing eight sports were analyzed. The autobiographical analysis was informed by narrative tradition, using three types of narrative analysis: categorical content, categorical form, and holistic content. The analysis revealed a temporal aspect to the depressive experiences that the athletes reported. Initially, sport represented a form of escape from the depressive symptoms which had been exacerbated by both external stressors (e.g., experiencing bereavement) and internal stressors (e.g., low self-esteem). However, in time, the athletes typically reached a stage when the demands of their sport shifted from being facilitative to being debilitative in nature with an intensification of their depressive symptoms. This was accompanied by deliberations about continuing their engagement in sport and an acceptance that they could no longer escape from their symptoms, with or without sport. The findings extend the extant literature by suggesting a reciprocal relationship between depressive experiences and sport performance, and they support the general psychology literature relating to the negative impact of depression on performance. The applied implications of these findings are discussed emphasizing the importance of early identification of depressive symptoms and the adoption of a proactive approach in the prevention and management of symptoms.

  19. The Dark Side of Top Level Sport: An Autobiographic Study of Depressive Experiences in Elite Sport Performers

    PubMed Central

    Newman, Hannah J. H.; Howells, Karen L.; Fletcher, David

    2016-01-01

    The general and sport psychology research converge to point to a complex relationship between depressive experiences and human performance. The purpose of this study was to explore the depressive experiences of top level athletes and the relationship of such experiences with sport performance. Twelve autobiographies of elite athletes representing eight sports were analyzed. The autobiographical analysis was informed by narrative tradition, using three types of narrative analysis: categorical content, categorical form, and holistic content. The analysis revealed a temporal aspect to the depressive experiences that the athletes reported. Initially, sport represented a form of escape from the depressive symptoms which had been exacerbated by both external stressors (e.g., experiencing bereavement) and internal stressors (e.g., low self-esteem). However, in time, the athletes typically reached a stage when the demands of their sport shifted from being facilitative to being debilitative in nature with an intensification of their depressive symptoms. This was accompanied by deliberations about continuing their engagement in sport and an acceptance that they could no longer escape from their symptoms, with or without sport. The findings extend the extant literature by suggesting a reciprocal relationship between depressive experiences and sport performance, and they support the general psychology literature relating to the negative impact of depression on performance. The applied implications of these findings are discussed emphasizing the importance of early identification of depressive symptoms and the adoption of a proactive approach in the prevention and management of symptoms. PMID:27375544

  20. Another Side to the Coin: The Unintended Effects of the Publication of School Performance Data in England and France.

    ERIC Educational Resources Information Center

    Karsten, Sjoerd; Visscher, Adrie; De Jong, Tim

    2001-01-01

    Publication of school rankings based on raw data for various performance indicators was found to influence school choice and mobility strategies for elite and middle-class parents in England and France. Rather than promoting school improvement, publication led to unintended school coping strategies, such as marketing activities, student exclusion…

  1. High performance polymer electrolytes based on main and side chain pyridine aromatic polyethers for high and medium temperature proton exchange membrane fuel cells

    NASA Astrophysics Data System (ADS)

    Geormezi, M.; Chochos, C. L.; Gourdoupi, N.; Neophytides, S. G.; Kallitsis, J. K.

    Novel aromatic polyether type copolymers bearing side chain polar pyridine rings as well as combination of main and side chain pyridine units have been evaluated as potential polymer electrolytes for proton exchange membrane fuel cells (PEMFCs). The advanced chemical and physicochemical properties of these new polymers with their high oxidative stability, mechanical integrity and high glass transition temperatures (T g's up to 270 °C) and decomposition temperatures (T d's up to 480 °C) make them promising candidates for high and medium temperature proton exchange membranes in fuel cells. These copolymers exhibit adequate proton conductivities up to 0.08 S cm -1 even at moderate phosphoric acid doping levels. An optimized terpolymer chemical structure has been developed, which has been effectively tested as high temperature phosphoric acid imbibed polymer electrolyte. MEA prepared out of the novel terpolymer chemical structure is approaching state of the art fuel cell operating performance (135 mW cm -2 with electrical efficiency 45%) at high temperatures (150-180 °C) despite the low phosphoric acid content (<200 wt%) and the low platinum loading (ca. 0.7 mg cm -2). Durability tests were performed affording stable performance for more than 1000 h.

  2. Co3O4 nanoparticles decorated carbon nanofiber mat as binder-free air-cathode for high performance rechargeable zinc-air batteries.

    PubMed

    Li, Bing; Ge, Xiaoming; Goh, F W Thomas; Hor, T S Andy; Geng, Dongsheng; Du, Guojun; Liu, Zhaolin; Zhang, Jie; Liu, Xiaogang; Zong, Yun

    2015-02-07

    An efficient, durable and low cost air-cathode is essential for a high performance metal-air battery for practical applications. Herein, we report a composite bifunctional catalyst, Co3O4 nanoparticles-decorated carbon nanofibers (CNFs), working as an efficient air-cathode in high performance rechargeable Zn-air batteries (ZnABs). The particles-on-fibers nanohybrid materials were derived from electrospun metal-ion containing polymer fibers followed by thermal carbonization and a post annealing process in air at a moderate temperature. Electrochemical studies suggest that the nanohybrid material effectively catalyzes oxygen reduction reaction via an ideal 4-electron transfer process and outperforms Pt/C in catalyzing oxygen evolution reactions. Accordingly, the prototype ZnABs exhibit a low discharge-charge voltage gap (e.g. 0.7 V, discharge-charge at 2 mA cm(-2)) with higher stability and longer cycle life compared to their counterparts constructed using Pt/C in air-cathode. Importantly, the hybrid nanofiber mat readily serves as an integrated air-cathode without the need of any further modification. Benefitting from its efficient catalytic activities and structural advantages, particularly the 3D architecture of highly conductive CNFs and the high loading density of strongly attached Co3O4 NPs on their surfaces, the resultant ZnABs show significantly improved performance with respect to the rate capability, cycling stability and current density, promising good potential in practical applications.

  3. Improving Vortex Generators to Enhance the Performance of Air-Cooled Condensers in a Geothermal Power Plant

    SciTech Connect

    Manohar S. Sohal

    2005-09-01

    This report summarizes work at the Idaho National Laboratory to develop strategies to enhance air-side heat transfer in geothermal air-cooled condensers such that it should not significantly increase pressure drop and parasitic fan pumping power. The work was sponsored by the U.S. Department of Energy, NEDO (New Energy and Industrial Technology Development Organization) of Japan, Yokohama National University, and the Indian Institute of Technology, Kanpur, India. A combined experimental and numerical investigation was performed to investigate heat transfer enhancement techniques that may be applicable to largescale air-cooled condensers such as those used in geothermal power applications. A transient heat transfer visualization and measurement technique was employed in order to obtain detailed distributions of local heat transfer coefficients on model fin surfaces. Pressure drop measurements were obtained for a variety of tube and winglet configurations using a single-channel flow apparatus that included four tube rows in a staggered array. Heat transfer and pressure drop measurements were also acquired in a separate multiple-tube row apparatus in the Single Blow Test Facility. In addition, a numerical modeling technique was developed to predict local and average heat transfer for these low-Reynolds number flows, with and without winglets. Representative experimental and numerical results were obtained that reveal quantitative details of local finsurface heat transfer in the vicinity of a circular tube with a single delta winglet pair downstream of the cylinder. Heat transfer and pressure-drop results were obtained for flow Reynolds numbers based on channel height and mean flow velocity ranging from 700 to 6500. The winglets were of triangular (delta) shape with a 1:2 or 1:3 height/length aspect ratio and a height equal to 90% of the channel height. Overall mean fin-surface heat transfer results indicate a significant level of heat transfer enhancement (in terms of

  4. Cross-Cultural Skills for Deployed Air Force Personnel: Defining Cross-Cultural Performance

    DTIC Science & Technology

    2009-01-01

    a currently valid OMB control number. 1. REPORT DATE 2009 2. REPORT TYPE final 3. DATES COVERED 00-00-2009 to 00-00-2009 4. TITLE AND...Investigations PAF Project Air Force PME professional military education ROE rules of engagement SOP standard operating procedure TCN third-country...recognize that efforts labeled as education (e.g., pro- fessional military education, or PME ) also play a role in improving job performance.2 Thus, even

  5. Indoor test for thermal performance evaluation on the Sunworks (air) solar collector

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The test procedure used and the results obtained from an evaluation test program conducted to obtain thermal performance data on a Sunworks single glazed air solar collector under simulated conditions are described. A time constant test and incident angle modifier test were conducted to determine the transient effect and the incident angle effect on the collector. These results and the results of the collector load test are also discussed.

  6. Relationships of Type A Behavior with Biographical Characteristics and Training Performance of Air Traffic Controllers

    DTIC Science & Technology

    1994-07-01

    Helmreich, Beane , predictive of performance in the Academy screen and Lucker (1980), using the Jenkins Activity Survey, program. demonstrated that...Making it without losing it: Type A, achievement Matthews, K. A., Helmreich, R. L., Beane , W. F., & motivation, and scientific attainment revisited. Lucker...Aviation Medicine Report, the new aptitude testing procedures for selection DOT/ FAVA /A I-78-39. of FAA air traffic control specialists. In Schroeder, D. J

  7. Analytical predictions of liquid and air photovoltaic/thermal flat-plate collector performance

    SciTech Connect

    Raghuraman, P.; Hendrie, S. D.

    1980-01-01

    Two separate one-dimensional analyses have been developed for the prediction of the thermal and electrical performance of both liquid and air flat-plate photovoltaic/thermal (PV/T) collectors. The analyses account for the temperature difference between the primary insolation absorber (the photovoltaic cells) and the secondary absorber (a thermal absorber flat plate). The results of the analyses are compared with test measurements, and therefrom, design recommendations are made to maximize the total energy extracted from the collectors.

  8. Seasonal versus Episodic Performance Evaluation for an Eulerian Photochemical Air Quality Model

    SciTech Connect

    Jin, Ling; Brown, Nancy J.; Harley, Robert A.; Bao, Jian-Wen; Michelson, Sara A; Wilczak, James M

    2010-04-16

    This study presents detailed evaluation of the seasonal and episodic performance of the Community Multiscale Air Quality (CMAQ) modeling system applied to simulate air quality at a fine grid spacing (4 km horizontal resolution) in central California, where ozone air pollution problems are severe. A rich aerometric database collected during the summer 2000 Central California Ozone Study (CCOS) is used to prepare model inputs and to evaluate meteorological simulations and chemical outputs. We examine both temporal and spatial behaviors of ozone predictions. We highlight synoptically driven high-ozone events (exemplified by the four intensive operating periods (IOPs)) for evaluating both meteorological inputs and chemical outputs (ozone and its precursors) and compare them to the summer average. For most of the summer days, cross-domain normalized gross errors are less than 25% for modeled hourly ozone, and normalized biases are between {+-}15% for both hourly and peak (1 h and 8 h) ozone. The domain-wide aggregated metrics indicate similar performance between the IOPs and the whole summer with respect to predicted ozone and its precursors. Episode-to-episode differences in ozone predictions are more pronounced at a subregional level. The model performs consistently better in the San Joaquin Valley than other air basins, and episodic ozone predictions there are similar to the summer average. Poorer model performance (normalized peak ozone biases <-15% or >15%) is found in the Sacramento Valley and the Bay Area and is most noticeable in episodes that are subject to the largest uncertainties in meteorological fields (wind directions in the Sacramento Valley and timing and strength of onshore flow in the Bay Area) within the boundary layer.

  9. High Performance Polymer Film Dielectrics for Air Force Wide-Temperature Power Electronics Applications (Preprint)

    DTIC Science & Technology

    2009-02-01

    perform, display, or disclose the work. 14. ABSTRACT Air Force currently has a strong need for the development of compact capacitors which are... capacitors typically use polycarbonate (PC) dielectric films in wound capacitors for operation from -55 ºC to 125 ºC, future power electronic systems would...such as fluorinated polybenzoxazoles (6F-PBO) and fluorenyl polyesters incorporating diamond-like hydrocarbon units (FDAPE). The discussion will be

  10. Materials performance in the atmospheric fluidized-bed cogeneration air heater experiment

    SciTech Connect

    Natesan, K.; Podolski, W.; Wang, D.Y.; Teats, F.G. ); Gerritsen, W.; Stewart, A.; Robinson, K. )

    1991-02-01

    The Atmospheric Fluidized-Bed Cogeneration Air Heater Experiment (ACAHE) sponsored by the US Department of Energy (DOE) was initiated to assess the performance of various heat-exchanger materials to be used in fluidized-bed combustion air heater systems. Westinghouse Electric Corporation, through subcontracts with Babcock Wilcox, Foster Wheeler, and ABB Combustion Engineering Systems, prepared specifications and hardware for the ACAHE tests. Argonne National Laboratory contracted with Rockwell International to conduct tests in the DOE atmospheric fluidized-bed combustion facility. This report presents an overview of the project, a description of the facility and the test hardware, the test operating conditions, a summary of the operation, and the results of analyzing specimens from several uncooled and cooled probes exposed in the facility. Extensive microstructural analyses of the base alloys, claddings, coatings, and weldments were performed on specimens exposed in several probes for different lengths of time. Alloy penetration data were determined for several of the materials as a function of specimen orientation and the exposure location in the combustor. Finally, the data were compared with earlier laboratory test data, and the long-term performance of candidate materials for air-heater applications was assessed.

  11. Effect of refrigerant charge on the performance of air-conditioning systems

    SciTech Connect

    Goswami, D.Y.; Ek, G.; Leung, M.; Jotshi, C.K.; Sherif, S.A.; Colacino, F.

    1997-12-31

    An air-conditioning system operates in an optimal condition if the system is fully charged with specified amount of refrigerant. Poor field maintenance or refrigerant leakage causes low level of charge resulting in a lower thermal performance and higher operating cost. An experimental investigation was conducted to study the effect of low charge level of R-22 on the performance of a 3-ton residential air-conditioning system. The experimental results show that if a system is undercharged to 90%, the effect is small, 3.5% reduction in cooling capacity and 2% increase in COP. However, the system performance suffers serious degradation if the level of charge drops below 80%. An ice layer formed on the outer cooling coil surface impedes the heat transfer between the warm air and cold refrigerant vapor. An economic analysis shows that the cost of properly charging a system which has otherwise gone down to 85% charge level can pay for itself in savings in a short period of 3 to 4 months.

  12. Materials performance in the atmospheric fluidized-bed cogeneration air heater experiment

    SciTech Connect

    Natesan, K.; Podolski, W.; Wang, D.Y.; Teats, F.G.; Gerritsen, W.; Stewart, A.; Robinson, K.

    1991-02-01

    The Atmospheric Fluidized-Bed Cogeneration Air Heater Experiment (ACAHE) sponsored by the US Department of Energy (DOE) was initiated to assess the performance of various heat-exchanger materials to be used in fluidized-bed combustion air heater systems. Westinghouse Electric Corporation, through subcontracts with Babcock & Wilcox, Foster Wheeler, and ABB Combustion Engineering Systems, prepared specifications and hardware for the ACAHE tests. Argonne National Laboratory contracted with Rockwell International to conduct tests in the DOE atmospheric fluidized-bed combustion facility. This report presents an overview of the project, a description of the facility and the test hardware, the test operating conditions, a summary of the operation, and the results of analyzing specimens from several uncooled and cooled probes exposed in the facility. Extensive microstructural analyses of the base alloys, claddings, coatings, and weldments were performed on specimens exposed in several probes for different lengths of time. Alloy penetration data were determined for several of the materials as a function of specimen orientation and the exposure location in the combustor. Finally, the data were compared with earlier laboratory test data, and the long-term performance of candidate materials for air-heater applications was assessed.

  13. Impact of air and refrigerant maldistributions on the performance of finned-tube evaporators with R-22 and R-407C. Final Report

    SciTech Connect

    Lee, Jangho; Domanski, P.A.

    1997-07-01

    The report presents basic features of the evaporator model, EVAP5M, and simulation results for an evaporator operating with R-22 and R-407C at non-uniform air and refrigerant distributions. EVAP5M was developed under this project to provide a tool for simulating a finned-tube air-to refrigerant evaporator operating with single-component refrigerants and refrigerant mixtures. The tube-by-tube modeling approach allowed for one-dimensional non-uniformity in the air velocity profile and arbitrary maldistribution on the refrigerant side. The model uses the Carnahan-Starling-DeSantis equation of state for calculating refrigerant thermodynamic properties. Simulations were performed for three evaporator slabs with different refrigerant circuitry designs. For the maldistributions studied, maldistributed air caused much more significant capacity degradation than maldistributed refrigerant. In some cases capacity decreased to as low as 57 percent of the value obtained for uniform velocity profile. Simulation results showed that R-22 and R-407C have similar susceptibility to capacity degradation. Relative change of capacity varied depending on the evaporator design and maldistribution studied. 17 refs., 18 figs., 9 tabs.

  14. Preservation of Cognitive Performance with Age during Exertional Heat Stress under Low and High Air Velocity

    PubMed Central

    Wright Beatty, Heather E.; Keillor, Jocelyn M.; Hardcastle, Stephen G.; Boulay, Pierre; Kenny, Glen P.

    2015-01-01

    Older adults may be at greater risk for occupational injuries given their reduced capacity to dissipate heat, leading to greater thermal strain and potentially cognitive decrements. Purpose. To examine the effects of age and increased air velocity, during exercise in humid heat, on information processing and attention. Methods. Nine young (24 ± 1 years) and 9 older (59 ± 1 years) males cycled 4 × 15 min (separated by 15 min rest) at a fixed rate of heat production (400 W) in humid heat (35°C, 60% relative humidity) under 0.5 (low) and 3.0 (high) m·s−1 air velocity wearing coveralls. At rest, immediately following exercise (end exercise), and after the final recovery, participants performed an abbreviated paced auditory serial addition task (PASAT, 2 sec pace). Results. PASAT numbers of correct responses at end exercise were similar for young (low = 49 ± 3; high = 51 ± 3) and older (low = 46 ± 5; high = 47 ± 4) males and across air velocity conditions, and when scored relative to age norms. Psychological sweating, or an increased sweat rate with the administration of the PASAT, was observed in both age groups in the high condition. Conclusion. No significant decrements in attention and speeded information processing were observed, with age or altered air velocity, following intermittent exercise in humid heat. PMID:25874223

  15. Performance and economic enhancement of cogeneration gas turbines through compressor inlet air cooling

    NASA Astrophysics Data System (ADS)

    Delucia, M.; Bronconi, R.; Carnevale, E.

    1994-04-01

    Gas turbine air cooling systems serve to raise performance to peak power levels during the hot months when high atmospheric temperatures cause reductions in net power output. This work describes the technical and economic advantages of providing a compressor inlet air cooling system to increase the gas turbine's power rating and reduce its heat rate. The pros and cons of state-of-the-art cooling technologies, i.e., absorption and compression refrigeration, with and without thermal energy storage, were examined in order to select the most suitable cooling solution. Heavy-duty gas turbine cogeneration systems with and without absorption units were modeled, as well as various industrial sectors, i.e., paper and pulp, pharmaceuticals, food processing, textiles, tanning, and building materials. The ambient temperature variations were modeled so the effects of climate could be accounted for in the simulation. The results validated the advantages of gas turbine cogeneration with absorption air cooling as compared to other systems without air cooling.

  16. Room temperature, air crystallized perovskite film for high performance solar cells

    SciTech Connect

    Dubey, Ashish; Kantack, Nicholas; Adhikari, Nirmal; Reza, Khan Mamun; Venkatesan, Swaminathan; Kumar, Mukesh; Khatiwada, Devendra; Darling, Seth; Qiao, Qiquan

    2016-05-31

    For the first time, room temperature heating free growth and crystallization of perovskite films in ambient air without the use of thermal annealing is reported. Highly efficient perovskite nanorod-based solar cells were made using ITO/PEDOT:PSS/CH3NH3PbI3 nanorods/PC60BM/rhodamine/Ag. All the layers except PEDOT:PSS were processed at room temperature thereby eliminating the need for thermal treatment. Perovskite films were spin coated inside a N-2 filled glovebox and immediately were taken outside in air having 40% relative humidity (RH). Exposure to humid air was observed to promote the crystallization process in perovskite films even at room temperature. Perovskite films kept for 5 hours in ambient air showed nanorod-like morphology having high crystallinity, with devices exhibiting the highest PCE of 16.83%, which is much higher than the PCE of 11.94% for traditional thermally annealed perovskite film based devices. Finally, it was concluded that moisture plays an important role in room temperature crystallization of pure perovskite nanorods, showing improved optical and charge transport properties, which resulted in high performance solar cells.

  17. Room temperature, air crystallized perovskite film for high performance solar cells

    DOE PAGES

    Dubey, Ashish; Kantack, Nicholas; Adhikari, Nirmal; ...

    2016-05-31

    For the first time, room temperature heating free growth and crystallization of perovskite films in ambient air without the use of thermal annealing is reported. Highly efficient perovskite nanorod-based solar cells were made using ITO/PEDOT:PSS/CH3NH3PbI3 nanorods/PC60BM/rhodamine/Ag. All the layers except PEDOT:PSS were processed at room temperature thereby eliminating the need for thermal treatment. Perovskite films were spin coated inside a N-2 filled glovebox and immediately were taken outside in air having 40% relative humidity (RH). Exposure to humid air was observed to promote the crystallization process in perovskite films even at room temperature. Perovskite films kept for 5 hours inmore » ambient air showed nanorod-like morphology having high crystallinity, with devices exhibiting the highest PCE of 16.83%, which is much higher than the PCE of 11.94% for traditional thermally annealed perovskite film based devices. Finally, it was concluded that moisture plays an important role in room temperature crystallization of pure perovskite nanorods, showing improved optical and charge transport properties, which resulted in high performance solar cells.« less

  18. Performance of commercial aluminium alloys as anodes in gelled electrolyte aluminium-air batteries

    NASA Astrophysics Data System (ADS)

    Pino, M.; Chacón, J.; Fatás, E.; Ocón, P.

    2015-12-01

    The evaluation of commercial aluminium alloys, namely, Al2024, Al7475 and Al1085, for Al-air batteries is performed. Pure Al cladded Al2024 and Al7475 are also evaluated. Current rates from 0.8 mA cm-2 to 8.6 mA cm-2 are measured in a gel Al-air cell composed of the commercial alloy sample, a commercial air-cathode and an easily synthesizable gelled alkaline electrolyte. The influence of the alloying elements and the addition to the electrolyte of ZnO and ZnCl2, as corrosion inhibitors is studied and analysed via EDX/SEM. Specific capacities of up to 426 mAh/g are obtained with notably flat potential discharges of 1.3-1.4 V. The competition between self-corrosion and oxidation reactions is also discussed, as well as the influence of the current applied on that process. Al7475 is determined to have the best behaviour as anode in Al-air primary batteries, and cladding process is found to be an extra protection against corrosion at low current discharges. Conversely, Al1085 provided worse results because of an unfavourable metallic composition.

  19. Transient performance and temperature field of a natural convection air dehumidifier loop

    NASA Astrophysics Data System (ADS)

    Fazilati, Mohammad Ali; Sedaghat, Ahmad; Alemrajabi, Ali-Akbar

    2017-02-01

    In this paper, transient performance of the previously introduced natural convection heat and mass transfer loop is investigated for an air dehumidifier system. The performance of the loop is studied in different conditions of heat source/heat sink temperature and different startup desiccant concentrations. Unlike conventional loops, it is observed that natural convection of the fluid originates from the heat sink towards the heat source. The proper operation of the cycle is highly dependent on the heat sink/heat source temperatures. To reduce the time constant of the system, a proper desiccant concentration should be adopted for charge of the loop.

  20. Power Performance Test Report for the Southwest Windpower AIR-X Wind Turbine

    SciTech Connect

    van Dam, J.; Meadors, M.; Link, H.; Migliore, P.

    2003-09-01

    In the period from 14 October 2002 to 16 January 2003, an early production version of Southwest Windpower's AIR-X turbine was installed at the NWTC test site for acoustic noise testing. In addition to the signals required for the noise testing, additional instrumentation that allowed power performance testing in accordance with IEC 61400-12[1] was added. The results of that test are described in this report. Please note that this test and the test report are not an accredited power performance test/test report because parts of the NWTC quality assurance system were not followed.

  1. Hydrodynamic air lubricated compliant surface bearing for an automotive gas turbine engine. 1: Journal bearing performance

    NASA Technical Reports Server (NTRS)

    Ruscitto, D.; Mccormick, J.; Gray, S.

    1978-01-01

    A 38.1 mm (1.5 inch) diameter Hydresil Compliant Surface Air Lubricated Journal Bearing was designed and tested to obtain bearing performance characteristics at both room temperature and 315 C (600 F). Testing was performed at various speeds up to 60,000 rpm with varying loads. Rotating sensors provided an opportunity to examine the film characteristics of the compliant surface bearing. In addition to providing minimum film thickness values and profiles, many other insights into bearing operation were gained such as the influence of bearing fabrication accuracy and the influence of smooth foil deflection between the bumps.

  2. A Belief-Based Model of Air Traffic Controllers Performing Separation Assurance

    NASA Technical Reports Server (NTRS)

    Landry, S.J.

    2009-01-01

    A model of an air traffic controller performing a separation assurance task was produced. The model was designed to be simple to use and deploy in a simulator, but still provide realistic behavior. The model is based upon an evaluation of the safety function of the controller for separation assurance, and utilizes fast and frugal heuristics and belief networks to establish a knowledge set for the controller model. Based on this knowledge set, the controller acts to keep aircraft separated. Validation results are provided to demonstrate the model s performance.

  3. Effect of the Tin- versus Air-side Plate-glass Orientation on the Impact Response and Penetration Resistance of a Laminated Transparent Armour Structure

    DTIC Science & Technology

    2012-01-16

    versus tin-side test laminate strike surfaces. Subsequent to these findings computational simulations were carried out in order to establish if the...findings. In general, a good agreement was found between the computational and the experimental results. 15. SUBJECT TERMS 16. SECURITY CLASSIFICATION...find- ings, computational simulations were carried out in order to establish if the proposed borofloat material model could capture the prominent

  4. Performance Validation Approach for the GTX Air-Breathing Launch Vehicle

    NASA Technical Reports Server (NTRS)

    Trefny, Charles J.; Roche, Joseph M.

    2002-01-01

    The primary objective of the GTX effort is to determine whether or not air-breathing propulsion can enable a launch vehicle to achieve orbit in a single stage. Structural weight, vehicle aerodynamics, and propulsion performance must be accurately known over the entire flight trajectory in order to make a credible assessment. Structural, aerodynamic, and propulsion parameters are strongly interdependent, which necessitates a system approach to design, evaluation, and optimization of a single-stage-to-orbit concept. The GTX reference vehicle serves this purpose, by allowing design, development, and validation of components and subsystems in a system context. The reference vehicle configuration (including propulsion) was carefully chosen so as to provide high potential for structural and volumetric efficiency, and to allow the high specific impulse of air-breathing propulsion cycles to be exploited. Minor evolution of the configuration has occurred as analytical and experimental results have become available. With this development process comes increasing validation of the weight and performance levels used in system performance determination. This paper presents an overview of the GTX reference vehicle and the approach to its performance validation. Subscale test rigs and numerical studies used to develop and validate component performance levels and unit structural weights are outlined. The sensitivity of the equivalent, effective specific impulse to key propulsion component efficiencies is presented. The role of flight demonstration in development and validation is discussed.

  5. Development of a High Performance Air Source Heat Pump for the US Market

    SciTech Connect

    Abdelaziz, Omar; Shen, Bo; Gao, Zhiming; Baxter, Van D; Iu, Ipseng

    2011-01-01

    Heat pumps present a significant advantage over conventional residential heating technologies due to higher energy efficiencies and less dependence on imported oil. The US development of heat pumps dates back to the 1930 s with pilot units being commercially available in the 1950 s. Reliable and cost competitive units were available in the US market by the 1960 s. The 1973 oil embargo led to increased interest in heat pumps prompting significant research to improve performance, particularly for cold climate locations. Recent increasing concerns on building energy efficiency and environmental emissions have prompted a new wave of research in heat pump technology with special emphasis on reducing performance degradation at colder outdoor air temperatures. A summary of the advantages and limitations of several performance improvement options sought for the development of high performance air source heat pump systems for cold climate applications is the primary focus of this paper. Some recommendations for a high performance cold climate heat pump system design most suitable for the US market are presented.

  6. [Studies on the performance of the dental air turbine handpieces. (Part 2) Classification and rotational performance of the dental air turbine handpieces (author's transl)].

    PubMed

    Miyairi, H; Nagai, M; Muramatsu, A

    1980-01-01

    For the purpose of the clinical and technical uses, air turbine handpieces are widely used for the high speed cutting instruments. And then, there are the many kinds of air turbine handpieces which are classified with the standard, minutia and torque types etc. So, in this paper, we examined the rotational properties of air turbine handpieces in the consideration of these classifications. And the relations between the reduction of the rotational speed and the rotational loads on the handpieces are fundamentally investigated. As the results of these investigations, it was revealed that rotational forces of the toque type air turbine are very excellent and the rotational speed of the air bearing type air turbine is higher than that of other type handpieces. And we obtained the practical properties of the rotational ability of air hand pieces.

  7. Co3O4 nanoparticles decorated carbon nanofiber mat as binder-free air-cathode for high performance rechargeable zinc-air batteries

    NASA Astrophysics Data System (ADS)

    Li, Bing; Ge, Xiaoming; Goh, F. W. Thomas; Hor, T. S. Andy; Geng, Dongsheng; Du, Guojun; Liu, Zhaolin; Zhang, Jie; Liu, Xiaogang; Zong, Yun

    2015-01-01

    An efficient, durable and low cost air-cathode is essential for a high performance metal-air battery for practical applications. Herein, we report a composite bifunctional catalyst, Co3O4 nanoparticles-decorated carbon nanofibers (CNFs), working as an efficient air-cathode in high performance rechargeable Zn-air batteries (ZnABs). The particles-on-fibers nanohybrid materials were derived from electrospun metal-ion containing polymer fibers followed by thermal carbonization and a post annealing process in air at a moderate temperature. Electrochemical studies suggest that the nanohybrid material effectively catalyzes oxygen reduction reaction via an ideal 4-electron transfer process and outperforms Pt/C in catalyzing oxygen evolution reactions. Accordingly, the prototype ZnABs exhibit a low discharge-charge voltage gap (e.g. 0.7 V, discharge-charge at 2 mA cm-2) with higher stability and longer cycle life compared to their counterparts constructed using Pt/C in air-cathode. Importantly, the hybrid nanofiber mat readily serves as an integrated air-cathode without the need of any further modification. Benefitting from its efficient catalytic activities and structural advantages, particularly the 3D architecture of highly conductive CNFs and the high loading density of strongly attached Co3O4 NPs on their surfaces, the resultant ZnABs show significantly improved performance with respect to the rate capability, cycling stability and current density, promising good potential in practical applications.An efficient, durable and low cost air-cathode is essential for a high performance metal-air battery for practical applications. Herein, we report a composite bifunctional catalyst, Co3O4 nanoparticles-decorated carbon nanofibers (CNFs), working as an efficient air-cathode in high performance rechargeable Zn-air batteries (ZnABs). The particles-on-fibers nanohybrid materials were derived from electrospun metal-ion containing polymer fibers followed by thermal carbonization

  8. Thermal performance of MSFC hot air collectors under natural and simulated conditions

    NASA Technical Reports Server (NTRS)

    Shih, K., Sr.

    1977-01-01

    The procedures used and the results obtained from an evaluation test program conducted to determine the thermal performance and structural characteristics of selected MSFC--designed hot air collectors under both real and simulated environmental conditions are described. Five collectors were tested in the three phased program. A series of outdoor tests were conducted to determine stagnation temperatures on a typical bright day and to determine each collector's ability to withstand these temperatures. Two of the collectors experienced structural deformation sufficient to eliminate them from the remainder of the test program. A series of outdoor tests to evaluate the thermal performance of collector S/N 10 under certain test conditions were performed followed by a series of indoor tests to evaluate the thermal performance of the collector under closely controlled simulated conditions.

  9. Evaluation of the Air Quality Monitor's Performance on the International Space Station

    NASA Technical Reports Server (NTRS)

    Limero, Thomas; Reese, Eric; Ballard, Ken; Durham, Tamara

    2010-01-01

    The Air Quality Monitor (AQM) was flown to the International Space Station (ISS) as an experiment to evaluate its potential to replace the aging Volatile Organic Analyzer (VOA), which ceased operations in August 2009. The AQM (Figure 1) is a small gas chromatography/differential mobility spectrometer (GC/DMS) manufactured by Sionex. Data was presented at last year s ISIMS conference that detailed the preparation of the AQM for flight, including instrument calibration. Furthermore, initial AQM data was compared to VOA results from simultaneous runs of the two instruments. Although comparison with VOA data provided a measure of confidence in the AQM performance, it is the comparison with results from simultaneously acquired air samples (grab sample containers-GSCs) that will define the success (or failure) of the AQM performance. This paper will update the progress in the AQM investigation by comparing AQM data to results from the analyses of GSC samples, returned from ISS. Additionally, a couple of example will illustrate the AQM s ability to detect disruptions in the spacecraft s air quality. Discussion will also focus upon a few unexpected issues that have arisen and how these will be a addressed in the final operational unit now being built.

  10. Influence of the air gap between protective clothing and skin on clothing performance during flash fire exposure

    NASA Astrophysics Data System (ADS)

    Ghazy, Ahmed; Bergstrom, Donald J.

    2011-10-01

    A finite volume model was developed to simulate transient heat transfer in protective clothing during flash fire exposure. The model accounts for the combined conduction-radiation heat transfer in the air gap between the fabric and skin. The variation in the fabric and air gap properties with temperature and the thermochemical reactions in the fabric are also considered. This study investigates the influence of the air gap in protective clothing on the energy transfer through the clothing and hence on its performance. Different parameters that affect the conduction-radiation heat transfer through the air gap such as the air gap absorption coefficient and the air gap width were studied. Finally, the paper demonstrates that an innovative and potentially significant way to improve protective clothing performance is to reduce the emissivity on the backside of the fabric.

  11. The effect of prolonged exposure to 750 C air on the tribological performance of PM212

    NASA Technical Reports Server (NTRS)

    Bemis, Kirk; Bogdanski, Michael S.; Dellacorte, Christopher; Sliney, Harold E.

    1994-01-01

    The effect of prolonged exposure to 750 C air on the tribological performance and dimensional stability of PM212, a high temperature, self-lubricating composite, is studied. PM212, by weight, contains 70 percent metal-bonded Cr3C2, 15 percent BaF2/CaF2 eutectic, and 15 percent silver. Rub blocks were fabricated from PM212 by cold isostatic pressing followed by sintering. Prior to tribo-testing, the rub blocks were exposed to 750 C air for periods ranging from 100 to 1000 hours. Then, the rub blocks were slid against nickel-based superalloy disks in a double-rub-block tribometer in air under a 66 N load at temperatures from 25 to 750 C with a sliding velocity of 0.36 m/s. Unexposed rub blocks were tested for baseline comparison. Friction coefficients ranged from 0.24 to 0.37 for the unexposed rub blocks and from 0.32 to 0.56 for the exposed ones. Wear for both the composite blocks and superalloy disks was typically in the moderate to low range of 10(exp -5) to 10(exp -6) mm(exp 3)/N-m. Friction and wear data were similar for the rub blocks exposed for 100, 500, and 1000 hours. Prolonged exposure to 750 C air increased friction and wear of the PM212 rub blocks at room temperature, but their triboperformance remained unaffected at higher temperatures, probably due to the formation of lubricious metal oxides. Dimensional stability of the composite was studied by exposing specimens of varying thicknesses for 500 hours in air at 750 C. Block thicknesses were found to increase with increased exposure time until steady state was reached after 100 hours of exposure, probably due to oxidation.

  12. Performance Analysis of Air-to-Water Heat Pump in Latvian Climate Conditions

    NASA Astrophysics Data System (ADS)

    Kazjonovs, Janis; Sipkevics, Andrejs; Jakovics, Andris; Dancigs, Andris; Bajare, Diana; Dancigs, Leonards

    2014-12-01

    Strategy of the European Union in efficient energy usage demands to have a higher proportion of renewable energy in the energy market. Since heat pumps are considered to be one of the most efficient heating and cooling systems, they will play an important role in the energy consumption reduction in buildings aimed to meet the target of nearly zero energy buildings set out in the EU Directive 2010/31/EU. Unfortunately, the declared heat pump Coefficient of Performance (COP) corresponds to a certain outdoor temperature (+7 °C), therefore different climate conditions, building characteristics and settings result in different COP values during the year. The aim of this research is to investigate the Seasonal Performance factor (SPF) values of air-to-water heat pump which better characterize the effectiveness of heat pump in a longer selected period of time, especially during the winter season, in different types of residential buildings in Latvian climate conditions. Latvia has four pronounced seasons of near-equal length. Winter starts in mid-December and lasts until mid-March. Latvia is characterized by cold, maritime climate (duration of the average heating period being 203 days, the average outdoor air temperature during the heating period being 0.0 °C, the coldest five-day average temperature being -20.7 °C, the average annual air temperature being +6.2 °C, the daily average relative humidity being 79 %). The first part of this research consists of operational air-towater heat pump energy performance monitoring in different residential buildings during the winter season. The second part of the research takes place under natural conditions in an experimental construction stand which is located in an urban environment in Riga, Latvia. The inner area of this test stand, where air-to-water heat pump performance is analyzed, is 9 m2. The ceiling height is 3 m, all external wall constructions (U = 0.16 W/(m2K)) have ventilated facades. To calculate SPF, the

  13. High-performance all-polymer solar cells via side-chain engineering of the polymer acceptor: the importance of the polymer packing structure and the nanoscale blend morphology.

    PubMed

    Lee, Changyeon; Kang, Hyunbum; Lee, Wonho; Kim, Taesu; Kim, Ki-Hyun; Woo, Han Young; Wang, Cheng; Kim, Bumjoon J

    2015-04-17

    The effectiveness of side-chain engineering is demonstrated to produce highly efficient all-polymer solar cells (efficiency of 5.96%) using a series of naphthalene diimide-based polymer acceptors with controlled side chains. The dramatic changes in the polymer packing, blend morphology, and electron mobility of all-polymer solar cells elucidate clear trends in the photovoltaic performances.

  14. Research on inert gas narcosis and air velocity effects on metabolic performance

    NASA Technical Reports Server (NTRS)

    1974-01-01

    The effects of air velocity on metabolic performance are studied by using high forced airflow in a closed environment as a mechanism to control the concentration of volatile animal wastes. Air velocities between 100 and 200 ft/min are without significant effects on the metabolism of rats. At velocities of 200 ft/min and above, oxygen consumption and CO2 production as well as food consumption increase. In most instances, the changes are on the order of 5-10%. At the same time, the RQ for the animals increases slightly and generally correlates well with oxygen consumption and CO2 production. Experiments on the nature of inert gas narcosis show that halothane and methoxyflurane are rather potent inhibitors of the NADH:O2 oxidoreductase system in rats. These experiments suggest that the mechanism of inert gas narcosis is not mandatorily related to a membrane surface phenomenon.

  15. A laboratory assessment of air sparging performance on oil-contaminated soil

    SciTech Connect

    Harkness, M.R.; Bracco, A.A.; Ciampa, J.D.

    1995-12-31

    The efficacy of air sparging to remediate a subsurface plume of transformer oil is evaluated in a comprehensive laboratory study. Shake flask assays containing contaminated soil indicated the oil was highly (>80%) biodegradable by indigenous bacteria when oxygen, nitrogen, and phosphorous were supplied. From 50 to 60% of the oil was removed from the soil in a 169-day biodegradation rate study performed in laboratory soil columns designed to mimic air sparged conditions. Maximal total petroleum hydrocarbon (TPH) biodegradation rates of {approximately}70 mg/kg per day were observed in nutrient (N and P) amended columns at 23 C, based upon O{sub 2} uptake and CO{sub 2} production. The total TPH biodegraded in these columns was 3-fold higher than in an unamended control column.

  16. Experience-Based Mitigation of Age-Related Performance Declines: Evidence From Air Traffic Control

    PubMed Central

    Nunes, Ashley; Kramer, Arthur F.

    2010-01-01

    Previous research has found age-related deficits in a variety of cognitive processes. However, some studies have demonstrated age-related sparing on tasks where individuals have substantial experience, often attained over many decades. Here, the authors examined whether decades of experience in a fast-paced demanding profession, air traffic control (ATC), would enable older controllers to perform at high levels of proficiency. The authors also investigated whether older controllers would show diminished age-related decrements on domain-relevant cognitive abilities. Both young and old controllers and noncontrollers performed a battery of cognitive and ATC tasks. Results indicate that although high levels of experience can reduce the magnitude of age-related decline on the component processes that underlie complex task performance, this sparing is limited in scope. More important, however, the authors observed experience-based sparing on simulated ATC tasks, with the sparing being most evident on the more complex air traffic control tasks. These results suggest that given substantial experience, older adults may be quite capable of performing at high levels of proficiency on fast-paced demanding real-world tasks. The implications of these findings for global skilled labor shortages are discussed. PMID:19309213

  17. Analysis of AIRS and IASI System Performance Under Clear and Cloudy Conditions

    NASA Technical Reports Server (NTRS)

    Aumann, Hartmut H.; Strow, L. Larrabee

    2010-01-01

    The radiometric and spectral system performance of space-borne infrared radiometers is generally specified and analyzed under strictly cloud-free, spatially uniform and warm conditions, with the assumption that the observed performance applies to the full dynamic range under clear and cloudy conditions and that random noise cancels for the evaluation of the radiometric accuracy. Such clear conditions are found in only one percent of the data. Ninety nine percent of the data include clouds, which produce spatially highly non-uniform scenes with 11 micrometers window brightness temperatures as low as 200K. We use AIRS and IASI radiance spectra to compare system performance under clear and a wide range of cloudy conditions. Although the two instruments are in polar orbits, with the ascending nodes separated by four hours, daily averages already reveal surprisingly similar measurements. The AIRS and IASI radiometric performance based on the mean of large numbers of observation is comparable and agrees within 200 mK over a wide range of temperatures. There are also some unexpected differences at the 200 -500 mK level, which are of significance for climate applications. The results were verified with data from July 2007 through January 2010, but many can already be gleaned from the analysis of a single day of data.

  18. Impact of acute exposure to air pollution on the cardiorespiratory performance of military firemen.

    PubMed

    Oliveira, R S; Barros Neto, T L; Braga, A L F; Raso, V; Pereira, L A A; Morette, S R; Carneiro, R C

    2006-12-01

    The objective of the present study was to determine the impact of acute short-term exposure to air pollution on the cardiorespiratory performance of military firemen living and working in the city of Guarujá, São Paulo, Brazil. Twenty-five healthy non-smoking firemen aged 24 to 45 years had about 1 h of exposure to low and high levels of air pollution. The tests consisted of two phases: phase A, in Bertioga, a town with low levels of air pollution, and phase B, in Cubatão, a polluted town, with a 7-day interval between phases. The volunteers remained in the cities (Bertioga/Cubatão) only for the time required to perform the tests. Cumulative load 10 +/- 2 min-long exertion tests were performed on a treadmill, consisting of a 2-min stage at a load of 7 km/h, followed by increasing exertion of 1 km h-1 min-1 until the maximum individual limit. There were statistically significant differences (P < 0.05) in anaerobic threshold (AT) between Cubatão (35.04 +/- 4.91 mL kg-1 min-1) and Bertioga (36.98 +/- 5.62 mL kg-1 min-1; P = 0.01), in the heart rate at AT (AT HR; Cubatão 152.08 +/- 14.86 bpm, Bertioga 157.44 +/- 13.64 bpm; P = 0.001), and in percent maximal oxygen consumption at AT (AT%VO2max; Cubatão 64.56 +/- 6.55%, Bertioga 67.40 +/- 5.35%; P = 0.03). However, there were no differences in VO2max, maximal heart rate or velocity at AT (ATvel) observed in firemen between towns. The acute exposure to pollutants in Cubatão, SP, caused a significant reduction in the performance at submaximal levels of physical exertion.

  19. Understanding the Dehumidification Performance of Air-Conditioning Equipment at Part-Load Conditions

    SciTech Connect

    Don B. Shirey III; Hugh I. Henderson Jr; Richard A. Raustad

    2006-01-01

    Air conditioner cooling coils typically provide both sensible cooling and moisture removal. Data from a limited number of field studies (Khattar et al. 1985; Henderson and Rengarajan 1996; Henderson 1998) have demonstrated that the moisture removal capacity of a cooling coil degrades at part-load conditions--especially when the supply fan operates continuously while the cooling coil cycles on and off. Degradation occurs because moisture that condenses on the coil surfaces during the cooling cycle evaporates back into air stream when the coil is off. This degradation affects the ability of cooling equipment to maintain proper indoor humidity levels and may negatively impact indoor air quality. This report summarizes the results of a comprehensive project to better understand and quantify the moisture removal (dehumidification) performance of cooling coils at part-load conditions. A review of the open literature was initially conducted to learn from previous research on this topic. Detailed performance measurements were then collected for eight cooling coils in a controlled laboratory setting to understand the impact of coil geometry and operating conditions on transient moisture condensation and evaporation by the coils. Measurements of cooling coil dehumidification performance and space humidity levels were also collected at seven field test sites. Finally, an existing engineering model to predict dehumidification performance degradation for single-stage cooling equipment at part-load conditions (Henderson and Rengarajan 1996) was enhanced to include a broader range of fan control strategies and an improved theoretical basis for modeling off-cycle moisture evaporation from cooling coils. The improved model was validated with the laboratory measurements, and this report provides guidance for users regarding proper model inputs. The model is suitable for use in computerized calculation procedures such as hourly or sub-hourly building energy simulation programs (e

  20. Effect of air gap variation on the performance of single stator single rotor axial flux permanent magnet generator

    NASA Astrophysics Data System (ADS)

    Kasim, Muhammad; Irasari, Pudji; Hikmawan, M. Fathul; Widiyanto, Puji; Wirtayasa, Ketut

    2017-02-01

    The axial flux permanent magnet generator (AFPMG) has been widely used especially for electricity generation. The effect of the air gap variation on the characteristic and performances of single rotor - single stator AFPMG has been described in this paper. Effect of air gap length on the magnetic flux distribution, starting torque and MMF has been investigated. The two dimensional finite element magnetic method has been deployed to model and simulated the characteristics of the machine which is based on the Maxwell equation. The analysis has been done for two different air gap lengths which were 2 mm and 4 mm using 2D FEMM 4.2 software at no load condition. The increasing of air gap length reduces the air-gap flux density. For air gap 2 mm, the maximum value of the flux density was 1.04 T while 0.73 T occured for air gap 4 mm.. Based on the experiment result, the increasing air gap also reduced the starting torque of the machine with 39.2 Nm for air gap 2 mm and this value decreased into 34.2 Nm when the air gap increased to 4 mm. Meanwhile, the MMF that was generated by AFPMG decreased around 22% at 50 Hz due to the reduction of magnetic flux induced on stator windings. Overall, the research result showed that the variation of air gap has significant effect on the machine characteristics.

  1. Performance assessment of a solar-powered air quality and weather station placed on a school rooftop in Hong Kong

    EPA Science Inventory

    Emerging air pollution measurement technologies that require minimal infrastructure to deploy may lead to new insights on air pollution spatial variability in urban areas. Through a collaboration between the USEPA and HKEPD, this study evaluates the performance of a compact, roo...

  2. Examination of the Community Multiscale Air Quality (CMAQ) Model Performance over the North American and European Domains

    EPA Science Inventory

    The CMAQ modeling system has been used to simulate the air quality for North America and Europe for the entire year of 2006 as part of the Air Quality Model Evaluation International Initiative (AQMEII) and the operational model performance of O3, fine particulate matte...

  3. 5 CFR 842.811 - Deposits for second-level supervisory air traffic controller service performed before February 10...

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 5 Administrative Personnel 2 2014-01-01 2014-01-01 false Deposits for second-level supervisory air traffic controller service performed before February 10, 2004. 842.811 Section 842.811 Administrative... Regulations Pertaining to Noncodified Statutes § 842.811 Deposits for second-level supervisory air...

  4. 5 CFR 842.811 - Deposits for second-level supervisory air traffic controller service performed before February 10...

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 5 Administrative Personnel 2 2012-01-01 2012-01-01 false Deposits for second-level supervisory air traffic controller service performed before February 10, 2004. 842.811 Section 842.811 Administrative... Regulations Pertaining to Noncodified Statutes § 842.811 Deposits for second-level supervisory air...

  5. 5 CFR 842.811 - Deposits for second-level supervisory air traffic controller service performed before February 10...

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 5 Administrative Personnel 2 2013-01-01 2013-01-01 false Deposits for second-level supervisory air traffic controller service performed before February 10, 2004. 842.811 Section 842.811 Administrative... Regulations Pertaining to Noncodified Statutes § 842.811 Deposits for second-level supervisory air...

  6. 5 CFR 842.811 - Deposits for second-level supervisory air traffic controller service performed before February 10...

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 5 Administrative Personnel 2 2011-01-01 2011-01-01 false Deposits for second-level supervisory air traffic controller service performed before February 10, 2004. 842.811 Section 842.811 Administrative... Regulations Pertaining to Noncodified Statutes § 842.811 Deposits for second-level supervisory air...

  7. 5 CFR 842.811 - Deposits for second-level supervisory air traffic controller service performed before February 10...

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 5 Administrative Personnel 2 2010-01-01 2010-01-01 false Deposits for second-level supervisory air traffic controller service performed before February 10, 2004. 842.811 Section 842.811 Administrative... Regulations Pertaining to Noncodified Statutes § 842.811 Deposits for second-level supervisory air...

  8. Performance potential of air turbo-ramjet employing supersonic through-flow fan

    NASA Technical Reports Server (NTRS)

    Kepler, C. E.; Champagne, G. A.

    1989-01-01

    A study was conducted to assess the performance potential of a supersonic through-flow fan in an advanced engine designed to power a Mach-5 cruise vehicle. It included a preliminary evaluation of fan performance requirements and the desirability of supersonic versus subsonic combustion, the design and performance of supersonic fans, and the conceptual design of a single-pass air-turbo-rocket/ramjet engine for a Mach 5 cruise vehicle. The study results showed that such an engine could provide high thrust over the entire speed range from sea-level takeoff to Mach 5 cruise, especially over the transonic speed range, and high fuel specific impulse at the Mach 5 cruise condition, with the fan windmilling.

  9. Performance of R-410A Alternative Refrigerants in a Reciprocating Compressor Designed for Air Conditioning Applications

    SciTech Connect

    Shrestha, Som S; Vineyard, Edward Allan; Mumpower, Kevin

    2016-01-01

    In response to environmental concerns raised by the use of refrigerants with high Global Warming Potential (GWP), the Air-Conditioning, Heating, and Refrigeration Institute (AHRI) has launched an industry-wide cooperative research program, referred to as the Low-GWP Alternative Refrigerants Evaluation Program (AREP), to identify and evaluate promising alternative refrigerants for major product categories. After successfully completing the first phase of the program in December 2013, AHRI launched a second phase of the Low-GWP AREP in 2014 to continue research in areas that were not previously addressed, including refrigerants in high ambient conditions, refrigerants in applications not tested in the first phase, and new refrigerants identified since testing for the program began. Although the Ozone Depletion Potential of R-410A is zero, this refrigerant is under scrutiny due to its high GWP. Several candidate alternative refrigerants have already demonstrated low global warming potential. Performance of these low-GWP alternative refrigerants is being evaluated for Air conditioning and heat pump applications to ensure acceptable system capacity and efficiency. This paper reports the results of a series of compressor calorimeter tests conducted for the second phase of the AREP to evaluate the performance of R-410A alternative refrigerants in a reciprocating compressor designed for air conditioning systems. It compares performance of alternative refrigerants ARM-71A, L41-1, DR-5A, D2Y-60, and R-32 to that of R-410A over a wide range of operating conditions. The tests showed that, in general, cooling capacities were slightly lower (except for the R-32), but energy efficiency ratios (EER) of the alternative refrigerants were comparable to that of R-410A.

  10. Effects of hydraulic pressure on the performance of single chamber air-cathode microbial fuel cells.

    PubMed

    Cheng, Shaoan; Liu, Weifeng; Guo, Jian; Sun, Dan; Pan, Bin; Ye, Yaoli; Ding, Weijun; Huang, Haobin; Li, Fujian

    2014-06-15

    Scaling up of microbial fuel cells (MFCs) without losing power density requires a thorough understanding of the effect of hydraulic pressure on MFC performance. In this work, the performance of an activated carbon air-cathode MFC was evaluated under different hydraulic pressures. The MFC under 100 mmH2O hydraulic pressure produced a maximum power density of 1260 ± 24 mW m(-2), while the power density decreased by 24.4% and 44.7% as the hydraulic pressure increased to 500 mmH2O and 2000 mmH2O, respectively. Notably, the performance of both the anode and the cathode had decreased under high hydraulic pressures. Electrochemical impedance spectroscopy tests of the cathode indicated that both charge transfer resistance and diffusion transfer resistance increased with the increase in hydraulic pressure. Denaturing gradient gel electrophoresis of PCR-amplified partial 16S rRNA genes demonstrated that the similarity among anodic biofilm communities under different hydraulic pressures was ≥ 90%, and the communities of all MFCs were dominated by Geobacter sp. These results suggested that the reduction in power output of the single chamber air-cathode MFC under high hydraulic pressures can be attributed to water flooding of the cathode and suppression the metabolism of anodic exoelectrogenic bacteria.

  11. Enhanced Performance of non-PGM Catalysts in Air Operated PEM-Fuel Cells

    DOE PAGES

    Barkholtz, Heather M.; Chong, Lina; Kaiser, Zachary Brian; ...

    2016-10-13

    Here a non-platinum group metal (non-PGM) oxygen reduction catalyst was prepared from “support-free” zeolitic imidazolate framework (ZIF) precursor and tested in the proton exchange membrane fuel cell with air as the cathode feed. The iron nitrogen and carbon composite (FeeNeC) based catalyst has high specific surface area decorated uniformly with active sites, which redefines the triple phase boundary (TPB) and requires re-optimization of the cathodic membrane electrode fabrication to ensure efficient mass and charge transports to the catalyst surface. This study reports an effort in optimizing catalytic ink formulation for the membrane electrode preparation and its impact to the fuelmore » cell performance under air. Through optimization, the fuel cell areal current density as high as 115.2 mA/cm2 at 0.8 V or 147.6 mA/cm2 at 0.8 ViR-free has been achieved under one bar air. We also investigated impacts on fuel cell internal impedance and the water formation.« less

  12. The comparative performance of an aviation engine at normal and high inlet air temperatures

    NASA Technical Reports Server (NTRS)

    Gardiner, Arthur W; Schey, Oscar W

    1928-01-01

    This report presents some results obtained during an investigation to determine the effect of high inlet air temperature on the performance of a Liberty 12 aviation engine. The purpose of this investigation was to ascertain, for normal service carburetor adjustments and a fixed ignition advance, the relation between power and temperature for the range of carburetor air temperatures that may be encountered when supercharging to sea level pressure at altitudes of over 20,000 feet and without intercooling when using plain aviation gasoline and mixtures of benzol and gasoline. The results show that for the conditions of test, both the brake and indicated power decrease with increase in air temperature at a faster rate than given by the theoretical assumption that power varies inversely as the square root of the absolute temperature. On a brake basis, the order of the difference in power for a temperature difference of 120 degrees F. Is 3 to 5 per cent. The observed relation between power and temperature when using the 30-70 blend was found to be linear. But, although these differences are noted, the above theoretical assumption may be considered as generally applicable except where greater precision over a wide range of temperatures is desired, in which case it appears necessary to test the particular engine under the given conditions. (author)

  13. Enhanced Performance of non-PGM Catalysts in Air Operated PEM-Fuel Cells

    SciTech Connect

    Barkholtz, Heather M.; Chong, Lina; Kaiser, Zachary Brian; Xu, Tao; Liu, Di-Jia

    2016-10-13

    Here a non-platinum group metal (non-PGM) oxygen reduction catalyst was prepared from “support-free” zeolitic imidazolate framework (ZIF) precursor and tested in the proton exchange membrane fuel cell with air as the cathode feed. The iron nitrogen and carbon composite (FeeNeC) based catalyst has high specific surface area decorated uniformly with active sites, which redefines the triple phase boundary (TPB) and requires re-optimization of the cathodic membrane electrode fabrication to ensure efficient mass and charge transports to the catalyst surface. This study reports an effort in optimizing catalytic ink formulation for the membrane electrode preparation and its impact to the fuel cell performance under air. Through optimization, the fuel cell areal current density as high as 115.2 mA/cm2 at 0.8 V or 147.6 mA/cm2 at 0.8 ViR-free has been achieved under one bar air. We also investigated impacts on fuel cell internal impedance and the water formation.

  14. Los Alamos Controlled Air Incinerator for radioactive waste. Volume I. Rationale, process, equipment, performance, and recommendations

    SciTech Connect

    Neuls, A.S.; Draper, W.E.; Koenig, R.A.; Newmyer, J.M.; Warner, C.L.

    1982-08-01

    This two-volume report is a detailed design and operating documentation of the Los Alamos National Laboratory Controlled Air Incinerator (CAI) and is an aid to technology transfer to other Department of Energy contractor sites and the commercial sector. Volume I describes the CAI process, equipment, and performance, and it recommends modifications based on Los Alamos experience. It provides the necessary information for conceptual design and feasibility studies. Volume II provides descriptive engineering information such as drawing, specifications, calculations, and costs. It aids duplication of the process at other facilities.

  15. Cooling Performance of a Partially-Confined FC-72 Spray: The Effect of Dissolved Air (Postprint)

    DTIC Science & Technology

    2007-01-01

    concentration of dissolved air, 1 < C < 20%, chamber saturation pressure, 6.90E+4 < Psat < 8.27E+4 N/rn2, subcooling , 2 < DeltaTsc < 12 °C, volumetric flow ...W T = temperature, °C ∆T = Ts-Tsat, °C ∆Tsc = fluid subcooling , °C • V = volumetric flow rate, m3/s * Mechanical Engineering Co-op, AFRL/PRPS...investigated. Rainey et al. (2003) studied the effects of pressure, subcooling , and dissolved gas on the pool boiling heat transfer performance of a

  16. Performance of the Extensive Air Shower Array at the University of Puebla

    NASA Astrophysics Data System (ADS)

    Cotzomi, J.; Martinez, O.; Medina, M.; Moreno, E.; Salazar, H.; Pérez, L.; Ponce, G.; Villaseñor, L.; Garipov, G.; Khrenov, B.

    2003-07-01

    We report on the performance of the EAS-UAP extensive air shower array after one year of operation. The array is located at 19N 90W, 800 g /cm2 ; it was designed to measure the energy and arrival direction of primary cosmic rays with energies in the range of 1014 to 1016 eV. The array consists of 12 liquid scintillation detectors of 1m2 effective area distributed in a square grid of 20m that measure the lateral distribution function of the electromagnetic component and 3 large water Cherenkov detectors to help improve the measurement of the time profile of the signals.

  17. Indoor test for thermal performance evaluation on life sciences engineering (air) solar collector

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The test procedure used and the results obtained from an evaluation test program conducted to obtain thermal performance data on a life sciences double-glazed air solar collector under simulated conditions is discussed. These tests were made using the Marshall Space Flight Center's solar simulator. A time constant test and incident angle modifier test were also conducted to determine the transient effect and the incident angle effect on the collector. These results and the results of the collector load test are also discussed.

  18. Influence of fertilizer draw solution properties on the process performance and microbial community structure in a side-stream anaerobic fertilizer-drawn forward osmosis - ultrafiltration bioreactor.

    PubMed

    Kim, Youngjin; Li, Sheng; Chekli, Laura; Phuntsho, Sherub; Ghaffour, Noreddine; Leiknes, TorOve; Shon, Ho Kyong

    2017-02-27

    In this study, a side-stream anaerobic fertilizer-drawn forward osmosis (FDFO) and ultrafiltration (UF) membrane bioreactor (MBR) hybrid system was proposed and operated for 55days. The FDFO performance was first investigated in terms of flux decline with various fertilizers draw solution. Flux decline was very severe with all fertilizers due to the absence of aeration and the sticky property of sludge. Flux recovery by physical cleaning varied significantly amongst tested fertilizers which seriously affected biofouling in FDFO via reverse salt flux (RSF). Besides, RSF had a significant impact on nutrient accumulation in the bioreactor. These results indicated that nutrient accumulation negatively influenced the anaerobic activity. To elucidate these phenomena, bacterial and archaeal community structures were analyzed by pyrosequencing. Results showed that bacterial community structure was affected by fertilizer properties with less impact on archaeal community structure, which resulted in a reduction in biogas production and an increase in nitrogen content.

  19. Optimization of heat transfer by adjusting power ratios between top and side heaters for casting high-performance multi-crystalline silicon ingots

    NASA Astrophysics Data System (ADS)

    Chen, Wenliang; Wu, Zhiyong; Zhong, Genxiang; Ding, Junjing; Yu, Yunyang; Zhou, Xucheng; Huang, Xinming

    2016-10-01

    Numerical simulations were applied to analyze the effects of the power ratios between top and side heaters on the crystal-melt (c-m) interface and the thermal stress distribution during the solidification process. The simulation results showed that among the different increase velocities of the power ratio, increasing the power ratio uniformly provided a most favorable solidification process: a slightly convex c-m interface shape and low thermal stress were obtained. The optimized design was implemented in casting experiments, which showed that the high-performance multi-crystalline silicon ingot had a vertical columnar structure and a lower dislocation density. The average conversion efficiency of solar cells was about 0.08% higher with this design (18.24%) than with the original design (18.16%).

  20. Advances in shell side condensation for refrigerants

    NASA Astrophysics Data System (ADS)

    Webb, Ralph L.

    The design of shell and tube condensers used in air conditioning and refrigeration applications is discussed. The geometry of interest involves condensation on the shell side of a horizontal tube bundle. Enhanced heat transfer geometries are typically used for condensation on the shell side. The heat transfer is removed by water on the tube side, which typically have tube side enhancement. Single tube and row effect condensation data are presented. Thermal design methods for sizing of the condenser are outlined.

  1. Radial Clearance Found To Play a Key Role in the Performance of Compliant Foil Air Bearings

    NASA Technical Reports Server (NTRS)

    Radil, Kevin C.

    2003-01-01

    Compliant foil air bearings are at the forefront of the Oil-Free turbomachinery revolution, which supports gas turbine engines with hydrodynamic bearings that use air instead of oil as the working fluid. These types of bearings have been around for almost 50 years and have found a home in several commercial applications, such as in air cycle machines, turbocompressors, and microturbines, but are now being aggressively pursued for use in small and midrange aircraft gas turbine engines. Benefits include higher operating speeds and temperatures, lower maintenance costs, and greater reliability. The Oil-Free Turbomachinery team at the NASA Glenn Research Center is working to foster the transition of Oil-Free technology into gas turbine engines by performing in-house experiments on foil air bearings in order to gain a greater insight into their complex operating principles. A research program recently undertaken at Glenn focused on the concept of radial clearance and its influence on bearing performance. The tests were conducted on foil bearings with different radial clearances. As defined for a foil bearing, radial clearance is a measure of the small amount of shaft radial motion that is present from play that exists in the elastic support structure, such as between the top and bump foils and the bump foils and bearing shell (see the drawing). With an insufficient amount of radial clearance, the bearing imparts a high preload on the shaft, which when excessive, can reduce the loadcarrying capability of the bearing. On the other hand, systems using foil bearings with excessive radial clearance may experience rotordynamic instabilities because of low bearing preload. Therefore, without a more thorough understanding of radial clearance, it is difficult to accurately predict the performance of a given bearing design. The test program demonstrated that there is a direct correlation between radial clearance and the performance of foil air bearings. As shown in the graph, an

  2. Examining the Links between Air Toxics Risk and Academic Performance in the Great Lakes Region Using the TRI

    EPA Pesticide Factsheets

    A study aimed at understanding the distribution of air pollution from industrial sources around U.S. public schools, whether racial and socioeconomic disparities in such distribution exist, and if these burdens are linked with student performance/health.

  3. Optimization and investigation of the effect of velocity distribution of air curtains on the performance of food refrigerated display cabinets

    NASA Astrophysics Data System (ADS)

    Wu, XueHong; Chang, ZhiJuan; Ma, QiuYang; Lu, YanLi; Yin, XueMei

    2016-08-01

    This paper focuses on improving the performance of the vertical open refrigerated display cabinets (VORDC) by optimizing the structure of deflector, which is affected by inlet velocity and velocity distribution of air curtains. The results show that the temperature of products located at the front and at the rear reduces as the increases of inlet velocity of air curtains. The increase of the inlet velocity of air curtains can strengthen the disturbance inside the VORDC, and also decrease the temperature of products inside the VORDC; the increase of the outer velocity of air curtain will exacerbate the disturbance outside the VORDC and decrease air curtain's performance. The present study can provide a theoretical foundation for the design of VORDC.

  4. Design Evolution and Performance Characterization of the GTX Air-Breathing Launch Vehicle Inlet

    NASA Technical Reports Server (NTRS)

    DeBonis, J. R.; Steffen, C. J., Jr.; Rice, T.; Trefny, C. J.

    2002-01-01

    The design and analysis of a second version of the inlet for the GTX rocket-based combine-cycle launch vehicle is discussed. The previous design did not achieve its predicted performance levels due to excessive turning of low-momentum comer flows and local over-contraction due to asymmetric end-walls. This design attempts to remove these problems by reducing the spike half-angle to 10- from 12-degrees and by implementing true plane of symmetry end-walls. Axisymmetric Reynolds-Averaged Navier-Stokes simulations using both perfect gas and real gas, finite rate chemistry, assumptions were performed to aid in the design process and to create a comprehensive database of inlet performance. The inlet design, which operates over the entire air-breathing Mach number range from 0 to 12, and the performance database are presented. The performance database, for use in cycle analysis, includes predictions of mass capture, pressure recovery, throat Mach number, drag force, and heat load, for the entire Mach range. Results of the computations are compared with experimental data to validate the performance database.

  5. Performance Characteristics of a Normal-shock Side Inlet Located Downstream of a Canard Control Surface at Mach Numbers of 1.5 and 1.8/

    NASA Technical Reports Server (NTRS)

    Dryer, Murray; Beke, Andrew

    1952-01-01

    The performance characteristics of a downward canted normal-shock side (scoop) inlet located downstream of a triangular control surface are presented for free-stream Mach numbers of 1.5 and 1.8 in terms of total pressure recovery and mass flow ratio for various boundary-layer removal systems,angles of attack, control surface deflections and adverse yaw. An engine operating condition for a hypothetical turbojet engine is established, and the match point characteristics of the engine-inlet configuration are summarized. 520::It is shown that the diffuser performance increases with increased boundary-layer removal and decreases because of the presence of the wake from the forward control surface. At the higher angles of attack the wake passes over the inlet and does not affect the inlet performance. Adverse yaw reduces the total pressure recovery values below those for the unawed case. Magnitudes of the total pressure recovery were below the theoretical normal-shock recovery for the respective test Mach numbers.

  6. Sensitivity analysis of thermal performances of flat plate solar air heaters

    NASA Astrophysics Data System (ADS)

    Njomo, Donatien; Daguenet, Michel

    2006-10-01

    Sensitivity analysis is a mathematical tool, first developed for optimization methods, which aim is to characterize a system response through the variations of its output parameters following modifications imposed on the input parameters of the system. Such an analysis may quickly become laborious when the thermal model under consideration is complex or the number of input parameters is high. In this paper, we develop a mathematical model to analyse the heat exchanges in four different types of solar air collectors. When building this thermal model we show that for each collector, at quasi-steady state, the energy balance equations of the components of the collector cascade into a single first-order non-linear differential equation that is able to predict the thermal behaviour of the collector. Our heat transfer model clearly demonstrates the existence of an important dimensionless parameter, referred to as the thermal performance factor of the collector, that compares the useful thermal energy which can be extracted from the heater to the overall thermal losses of that collector for a given set of input parameters. A sensitivity analysis of our thermal model has been performed for the most significant input parameters such as the incident solar irradiation, the inlet fluid temperature, the air mass flow rate, the depth of the fluid channel, the number and nature of the transparent covers in order to measure the impact of each of these parameters on our model. An important result which can be drawn from this study is that the heat transfer model developed is robust enough to be used for thermal design studies of most known flat plate solar air heaters, but also of flat plate solar water collectors and linear solar concentrators.

  7. Incinerator performance: effects of changes in waste input and furnace operation on air emissions and residues.

    PubMed

    Astrup, Thomas; Riber, Christian; Pedersen, Anne Juul

    2011-10-01

    Waste incineration can be considered a robust technology for energy recovery from mixed waste. Modern incinerators are generally able to maintain relatively stable performance, but changes in waste input and furnace operation may affect emissions. This study investigated how inorganic air emissions and residue composition at a full-scale incinerator were affected by known additions of specific waste materials to the normal municipal solid waste (MSW) input. Six individual experiments were carried out (% ww of total waste input): NaCl (0.5%), shoes (1.6%), automobile shredder waste (14%), batteries (0.5%), poly(vinyl chloride) (5.5%) and chromate-cupper-arsenate impregnated wood (11%). Materials were selected based on chemical composition and potential for being included or excluded from the waste mix. Critical elements in the waste materials were identified based on comparison with six experiments including 'as-large-as-possible' changes in furnace operation (oxygen levels, air supply and burnout level) only using normal MSW as input. The experiments showed that effects from the added waste materials were significant in relation to: air emissions (in particular As, Cd, Cr, Hg, Sb), element transfer coefficients, and residue composition (As, Cd, Cl, Cr, Cu, Hg, Mo, Ni, Pb, S, Sb, Zn). Changes in furnace operation could not be directly linked to changes in emissions and residues. The results outlined important elements in waste which should be addressed in relation to waste incinerator performance. Likely ranges of element transfer coefficients were provided as the basis for sensitivity analysis of life-cycle assessment (LCA) results involving waste incinerator technologies.

  8. Outdoor test for thermal performance evaluation of the Owens-Illinois Sunpack SEC-601 (air) solar collector

    NASA Technical Reports Server (NTRS)

    1979-01-01

    The test procedures used and the test results obtained during the performance of an evaluation test program on the Owens-Illinois Sunpak, model SEC-601, air solar collector under natural outdoor weather conditions are presented. All testing activities were performed on a single module. The test was performed and the data evaluated as applicable to outdoor testing of solar collectors.

  9. Dissolved air flotation primary clarifier improves performance of biological waste treatment at a latex manufacturing facility

    SciTech Connect

    Miller, D.R.; Kerecz, B.J.; Davis, M.N.

    1996-12-31

    Air Products and Chemicals, Inc. operates a chemical manufacturing facility in Piedmont, SC which generates a high strength COD emulsion wastewater from latex manufacturing. The on-site wastewater treatment facility consisted of flow equalization, activated sludge treatment and gravity clarification. The inability of the biological system to assimilate the high strength emulsion wastwater loadings led to incomplete conversion within the activated sludge process and poor settling waste sludge with turbid final effluent high in COD, BOD and TSS. The facility installed a dissolved air flotation (DAF) clarifier to effectively remove greater than 99 percent of the wastewater emulsion solids ahead of the activated sludge system. An organic coagulant is used for emulsion destabilization instead of iron or aluminum metal coagulants, improving DAF clarifier performance and minimizing operational cost and system complexity. An innovative DAF float solids collection and handling system produces disposal solids concentrations of 50 - 60% total solids resulting in further waste disposal cost savings. By removing more than 99 percent of the emulsion solids with the DAF clarifier ahead of the activated sludge process, the waste-water treatment facility now consistently produces a high quality effluent low in COD, BOD, TSS and turbidity. Wastewater treatment performance improved dramatically, as evident by the facility receiving the Western Carolina Regional Sewer Authority`s {open_quotes}Best Pollution Prevention Program{close_quotes} award. In addition, the wastewater treatment facility can now process three times the pre-DAF waste loads.

  10. Methods for measuring performance of vehicle cab air cleaning systems against aerosols and vapours.

    PubMed

    Bémer, D; Subra, I; Régnier, R

    2009-06-01

    Vehicle cabs equipped with an effective air cleaning and pressurization system, fitted to agricultural and off-road machineries, isolate drivers from the polluted environment, in which they are likely to work. These cabs provide protection against particulate and gaseous pollutants generated by these types of work activities. Two laboratory methods have been applied to determining the performance characteristics of two cabs of different design, namely, optical counting-based measurement of a potassium chloride (KCl) aerosol and fluorescein aerosol-based tracing. Results of cab confinement efficiency measurements agreed closely for these two methods implemented in the study. Measurements showed that high confinement efficiencies can be achieved with cabs, which are properly designed in ventilation/cleaning/airtightness terms. We also noted the importance of filter mounting airtightness, in which the smallest defect is reflected by significant degradation in cab performance. Determination of clean airflow rate by monitoring the decrease in test aerosol concentration in the test chamber gave excellent results. This method could represent an attractive alternative to methods involving gas tracing or air velocity measurement at blowing inlets.

  11. The calibration and flight test performance of the space shuttle orbiter air data system

    NASA Technical Reports Server (NTRS)

    Dean, A. S.; Mena, A. L.

    1983-01-01

    The Space Shuttle air data system (ADS) is used by the guidance, navigation and control system (GN&C) to guide the vehicle to a safe landing. In addition, postflight aerodynamic analysis requires a precise knowledge of flight conditions. Since the orbiter is essentially an unpowered vehicle, the conventional methods of obtaining the ADS calibration were not available; therefore, the calibration was derived using a unique and extensive wind tunnel test program. This test program included subsonic tests with a 0.36-scale orbiter model, transonic and supersonic tests with a smaller 0.2-scale model, and numerous ADS probe-alone tests. The wind tunnel calibration was further refined with subsonic results from the approach and landing test (ALT) program, thus producing the ADS calibration for the orbital flight test (OFT) program. The calibration of the Space Shuttle ADS and its performance during flight are discussed in this paper. A brief description of the system is followed by a discussion of the calibration methodology, and then by a review of the wind tunnel and flight test programs. Finally, the flight results are presented, including an evaluation of the system performance for on-board systems use and a description of the calibration refinements developed to provide the best possible air data for postflight analysis work.

  12. Creep performance of oxide ceramic fiber materials at elevated temperature in air and in steam

    NASA Astrophysics Data System (ADS)

    Armani, Clinton J.

    Structural aerospace components that operate in severe conditions, such as extreme temperatures and detrimental environments, require structural materials that have superior long-term mechanical properties and that are thermochemically stable over a broad range of service temperatures and environments. Ceramic matrix composites (CMCs) capable of excellent mechanical performance in harsh environments are prime candidates for such applications. Oxide ceramic materials have been used as constituents in CMCs. However, recent studies have shown that high-temperature mechanical performance of oxide-oxide CMCs deteriorate in a steam-rich environment. The degradation of strength at elevated temperature in steam has been attributed to the environmentally assisted subcritical crack growth in the oxide fibers. Furthermore, oxide-oxide CMCs have shown significant increases in steady-state creep rates in steam. The present research investigated the effects of steam on the high-temperature creep and monotonic tension performance of several oxide ceramic materials. Experimental facilities were designed and configured, and experimental methods were developed to explore the influence of steam on the mechanical behaviors of ceramic fiber tows and of ceramic bulk materials under temperatures in the 1100--1300°C range. The effects of steam on creep behavior of Nextel(TM)610 and Nextel(TM)720 fiber tows were examined. Creep rates at elevated temperatures in air and in steam were obtained for both types of fibers. Relationships between creep rates and applied stresses were modeled and underlying creep mechanisms were identified. For both types of fiber tows, a creep life prediction analysis was performed using linear elastic fracture mechanics and a power-law crack velocity model. These results have not been previously reported and have critical design implications for CMC components operating in steam or near the recommended design limits. Predictions were assessed and validated via

  13. Effect of excess air on second-generation PFB combustion plant performance and economics

    SciTech Connect

    Robertson, A. ); Garland, R. ); Newby, R. ); Rehmat, A. ); Rubow, L. ); Bonk, D. )

    1990-01-01

    This paper presents a conceptual design of a 1.4-MPa (14-atm) coal-fired second-generation pressurized fluidized bed (PFB) combustion plant and identifies the performance and economic changes that result as the excess air and thus gas turbine-to-steam turbine power ratio, is changed. The performance of these plants, another second- generation PFB combustion plant, and a conventional pulverized-coal (PC)-fired plant with wet limestone flue gas desulfurization is compared. Depending upon the conditions selected, the PFB combustion plant can achieve a 45 percent efficiency (based on the higher heating value of the coal used as fuel) and a cost of electricity at least 20 percent lower than that of the conventional PC-fired plant.

  14. Comparative Cooling Season Performance of Air Distribution Systems in Multistory Townhomes

    SciTech Connect

    A. Poerschke; Beach, R.; Beggs, T.

    2016-08-26

    IBACOS investigated the performance of a small-diameter high velocity heat pump system compared to a conventional system in a new construction triplex townhouse. A ductless heat pump system also was installed for comparison, but the homebuyer backed out because of aesthetic concerns about that system. In total, two buildings, having identical solar orientation and comprised of six townhomes, were monitored for comfort and energy performance. Results show that the small-diameter system provides more uniform temperatures from floor to floor in the three-story townhome. No clear energy consumption benefit was observed from either system. The builder is continuing to explore the small-diameter system as its new standard system to provide better comfort and indoor air quality. The homebuilder also explored the possibility of shifting its townhome product to meet the U.S. Department of Energy Challenge Home National Program Requirements.

  15. [Studies on the performance of the dental air turbine handpieces. (Part 4) Analysis of the rotational performance of air turbine handpieces (N = N0 - CvFv gamma (author's transl)].

    PubMed

    Miyairi, H; Nagai, M; Fukuda, H; Muramatsu, A

    1981-04-01

    By the introduction of the diamond instruments and carbide burs measurably improved the quality and ease of cavity preparation, the several kinds of the air turbine handpieces, that is, standard type, torque type and miniature type air handpieces have been recently developed. In this paper, the performance tests of these air turbine handpieces have been carried out, and obtained the relations are indicated speeds and the vertical and horizontal loads or torque using the test bur. These relations are indicated by the logarithmic expressions, N = N0 - CvFv gamma, where N is the rotational speed of the air turbine handpieces during rotation, N0 is the free rotational speed of the air turbine handpieces, Fv is the vertical loads on the tests burs and Cv and gamma is the experimental constants. And then, the maximum performed work or the air turbine handpieces is presented by the expression as follows. W max = pimicrod/60(1/Cv)1/ gamma gamma (N0/gamma + 1)(1 + gamma)/gamma And we proposed the formula to be calculated for the performance ability of the air turbine handpieces.

  16. Influence of air on polybutadiene used in the preparation of stationary phases for high-performance liquid chromatography.

    PubMed

    Lopes, Nilva P; Collins, Kenneth E; Jardim, Isabel C S F

    2004-03-19

    A 100 ml bottle of polybutadiene, PBD, was repeatedly exposed to air over a period of 6 months. Samples were taken at time zero (PBD-0), after 3 months (PBD-3) and 6 months (PBD-6). These samples were sorbed onto HPLC silica by an open-air solution-evaporation procedure, which involved exposure to the atmosphere for 6 days. Portions of the three sets of samples were used to compare self-immobilization and the effects of 100 degrees C thermal treatments in air or nitrogen on HPLC performance of the resulting phases. It is concluded that self-immobilization is enhanced by prior exposure of sorbed PBD to air and subsequent heating at 100 degrees C further enhances column performance. The best performance (10(5) plates m(-1)) resulted from 4 h heating of PBD-6 material in nitrogen.

  17. Improved Performance of the Alkaline-Side CSEX Process for Cesium Extraction from Alkaline High-Level Waste Obtained by Characterization of the Effect of Surfactant Impurities

    SciTech Connect

    Delmau, L.H.

    1999-11-04

    Improved understanding and performance of the alkaline-side CSEX process has been obtained through the characterization of impurity effects that hinder complete stripping of cesium from the solvent. It is shown in this report that tests of the alkaline-side CSEX process conducted in the summer and fall of 1998 were complicated by the presence of common surfactant anions, undecyl- and dodecylsulfonate, as trace impurities in the two simulants tested. This conclusion was drawn from the results of a series of systematic extraction tests followed by a definitive identification by electrospray mass spectrometry (ES-MS). Based on this understanding, a straightforward preventative measure involving the addition of a lipophilic tertiary amine extractant at a small concentration to the solvent is proposed and demonstrated. As part of the task ''Fission Product Solvent Extraction'' supported by the Efficient Separations and Processing Crosscutting Program within the USDOE Office of Environmental Management, the alkaline-side CSEX process has been developed for removal of radio-cesium ({sup 137}Cs) from alkaline high-level wastes stored in underground tanks at the Hanford Site and Savannah River Site (SRS). As described in a previous report, tests conducted in Fiscal Year 1998 generally demonstrated performance meeting the requirements for cesium removal from the waste to be treated at the SRS. However, discrepancies in stripping behavior were shown to arise from unidentified differences ''in the batches of waste simulant employed for testing. Various effects such as solvent impurities, kinetics, contacting method, and counting method were eliminated as possible causes of the observed discrepancies. Tests in Fiscal Year 1999 reported herein confirmed the earlier suspicion that the simulants contained lipophilic anionic impurities. Extraction tests demonstrated that the impurities could be concentrated in the solvent, and by ES-MS in the negative-ion mode it was possible to

  18. DOPS (Direct Observation of Procedural Skills) in undergraduate skills-lab: Does it work? Analysis of skills-performance and curricular side effects

    PubMed Central

    Profanter, Christoph; Perathoner, Alexander

    2015-01-01

    Objective: Sufficient teaching and assessing clinical skills in the undergraduate setting becomes more and more important. In a surgical skills-lab course at the Medical University of Innsbruck fourth year students were teached with DOPS (direct observation of procedural skills). We analyzed whether DOPS worked or not in this setting, which performance levels could be reached compared to tutor teaching (one tutor, 5 students) and which curricular side effects could be observed. Methods: In a prospective randomized trial in summer 2013 (April – June) four competence-level-based skills were teached in small groups during one week: surgical abdominal examination, urethral catheterization (phantom), rectal-digital examination (phantom), handling of central venous catheters. Group A was teached with DOPS, group B with a classical tutor system. Both groups underwent an OSCE (objective structured clinical examination) for assessment. 193 students were included in the study. Altogether 756 OSCE´s were carried out, 209 (27,6%) in the DOPS- and 547 (72,3%) in the tutor-group. Results: Both groups reached high performance levels. In the first month there was a statistically significant difference (p<0,05) in performance of 95% positive OSCE items in the DOPS-group versus 88% in the tutor group. In the following months the performance rates showed no difference anymore and came to 90% in both groups. In practical skills the analysis revealed a high correspondence between positive DOPS (92,4%) and OSCE (90,8%) results. Discussion: As shown by our data DOPS furnish high performance of clinical skills and work well in the undergraduate setting. Due to the high correspondence of DOPS and OSCE results DOPS should be considered as preferred assessment tool in a students skills-lab. The approximation of performance-rates within the months after initial superiority of DOPS could be explained by an interaction between DOPS and tutor system: DOPS elements seem to have improved

  19. Performance assessment and transient optimization of multi-stage solid desiccant air conditioning systems with building PV/T integration

    NASA Astrophysics Data System (ADS)

    Gadalla, Mohamed; Saghafifar, Mohammad

    2016-09-01

    One of the popular solar air conditioning technologies is desiccant air conditioning. Nonetheless, single stage desiccant air conditioning systems' coefficient of performance (COP) are relatively low. Therefore, multi-stage solid desiccant air conditioning systems are recommended. In this paper, an integrated double-stage desiccant air conditioning systems and PV/T collector is suggested for hot and humid climates such as the UAE. The results for the PV/T implementation in the double-stage desiccant cooling system are assessed against the PV/T results for a single-stage desiccant air conditioning system. In order to provide a valid comparative evaluation between the single and double stage desiccant air conditioning systems, an identical PV/T module, in terms of dimensions, is incorporated into these systems. The overall required auxiliary air heating is abated by 46.0% from 386.8 MWh to 209.0 MWh by replacing the single stage desiccant air conditioning system with the proposed double stage configuration during June to October. Moreover, the overall averaged solar share during the investigated months for the single and double stage systems are 36.5% and 43.3%.

  20. A roundabout approach to control morphological orientation and solar-cell performance by modulating side-chain branching position in benzodithiophene-based polymers.

    PubMed

    Lee, Kyu Cheol; Song, Seyeong; Lee, Junghoon; Kim, Dong Suk; Kim, Jin Young; Yang, Changduk

    2015-04-27

    To be meaningful to guide the rational design of novel high-performance conjugated semiconductors, we prepared three benzo[1,2-b:4,5-b']dithiophene (BDT)-based polymers by systematically moving the branching point of the alkyl chain. The effect of side-chain engineering was thoroughly investigated by a range of techniques. We demonstrate that a subtle change in the branching position in the BDT core can have a critical impact on polymer packing and preferential backbone orientation in thin films; copolymers made from BDT and thieno[3,4-c]pyrrole-4,6-dione units (TPD) adopt more of a face-on orientation as the branching point is shifted closer to the backbone, which can be correlated with a dramatic difference in solar-cells performance. The high short-circuit current density (11.6 mA cm(-2) ) for the copolymer with one carbon atom between the alkoxylated oxygen atom and the branching point results from its predominantly face-on orientation and smoother surface in thin films, which results in power conversion efficiencies as high as 4.56 %.

  1. Meteorological conditions are associated with physical activities performed in open-air settings

    NASA Astrophysics Data System (ADS)

    Suminski, Richard R.; Poston, Walker C.; Market, Patrick; Hyder, Melissa; Sara, Pyle A.

    2008-01-01

    Meteorological conditions (MC) are believed to modify physical activity. However, studies in this area are limited and none have looked at the associations between MC and physical activity in open-air settings. Therefore, we examined the relationships between MC and physical activities performed on sidewalks/streets and outdoor oval tracks. Observation techniques were used to count individuals walking to school, exercising on oval tracks and walking/jogging/biking on sidewalks/streets. Meteorological conditions were obtained from an Automated Surface Observing System located at a nearby airport for the same time periods physical activities were observed. On weekdays, fewer children were seen walking to school and more bicyclists were observed on sidewalks/streets as wind speed increased ( p < 0.05). Ambient and apparent temperatures were positively ( p < 0.05) and humidity and barometric pressure negatively ( p < 0.005) related to the number of individuals walking on the track. Meteorological conditions were not significantly associated with physical activities observed on weekends. Multiple linear regression analyses showed that apparent temperature (+), barometric pressure (-) and dew point (-) accounted for 58.0% of the variance in the number of walkers on the track. A significant proportion of the variance (>30%) in the number of joggers and the length of time they jogged was accounted for by apparent temperature (+) and dew point (-). We found that meteorological conditions are related to physical activity in open-air settings. The results embellish the context in which environmental-physical activity relationships should be interpreted and provide important information for researchers applying the observation method in open-air settings.

  2. Small-sided games versus interval training in amateur soccer players: effects on the aerobic capacity and the ability to perform intermittent exercises with changes of direction.

    PubMed

    Dellal, Alexandre; Varliette, Christophe; Owen, Adam; Chirico, Erica N; Pialoux, Vincent

    2012-10-01

    The purpose of this study was to compare the effects of small-sided games (SSGs) in soccer versus high-intensity intermittent training (HIT) on a continuous aerobic test (Vameval) and the performance in an intermittent test with changes of direction (CODs; 30-15 intermittent fitness test [30-15(IFT)]). Twenty-two amateur soccer players (mean age ± SD: 26.3 ± 4.7 years) were assigned to 3 different groups for 6 weeks: SSG group (n = 8), HIT group (n = 8), and control group (CG; n = 6). In addition to the usual technical and tactical sessions and competitive games, the SSG group performed 9 sessions of 2 versus 2 and 1 versus 1 SSGs, whereas the HIT group performed 9 sessions of intermittent runs in the form of 30 seconds of effort interspersed with 30 seconds of passive recovery (30s-30s), 15s-15s, and 10s-10s. The HIT and SSG groups showed performance improvements in the Vameval test (5.1 and 6.6%, respectively) and the 30-15(IFT) intermittent test with CODs (5.1 and 5.8%, respectively), whereas there was no change in the performance of the CG. Players from HIT and SSG groups showed similar increase in their performance in the 30-15(IFT) and the Vameval tests during the 6-week training period, especially with an increase significantly different to that in a traditional training as in the CG (p < 0.05). This investigation demonstrates that both SSG and HIT interventions are equally effective in developing the aerobic capacity and the ability to perform intermittent exercises with CODs in male amateur soccer players. Furthermore, these 2 methods of training applied during the 6 weeks induce similar effect on the recovery capacity and on the ability to repeat directional changes of 180°. Coaches will now be able to choose between these two methods according to the objective of the training and to optimize the training.

  3. Design and manufacturing considerations for high-performance gimbals used for land, sea, air, and space

    NASA Astrophysics Data System (ADS)

    Sweeney, Mike; Redd, Lafe; Vettese, Tom; Myatt, Ray; Uchida, David; Sellers, Del

    2015-09-01

    High performance stabilized EO/IR surveillance and targeting systems are in demand for a wide variety of military, law enforcement, and commercial assets for land, sea, air, and space. Operating ranges, wavelengths, and angular resolution capabilities define the requirements for EO/IR optics and sensors, and line of sight stabilization. Many materials and design configurations are available for EO/IR pointing gimbals depending on trade-offs of size, weight, power (SWaP), performance, and cost. Space and high performance military aircraft applications are often driven toward expensive but exceptionally performing beryllium and aluminum beryllium components. Commercial applications often rely on aluminum and composite materials. Gimbal design considerations include achieving minimized mass and inertia simultaneous with demanding structural, thermal, optical, and scene stabilization requirements when operating in dynamic operational environments. Manufacturing considerations include precision lapping and honing of ball bearing interfaces, brazing, welding, and casting of complex aluminum and beryllium alloy structures, and molding of composite structures. Several notional and previously developed EO/IR gimbal platforms are profiled that exemplify applicable design and manufacturing technologies.

  4. Nocturnal air, road, and rail traffic noise and daytime cognitive performance and annoyance.

    PubMed

    Elmenhorst, Eva-Maria; Quehl, Julia; Müller, Uwe; Basner, Mathias

    2014-01-01

    Various studies indicate that at the same noise level and during the daytime, annoyance increases in the order of rail, road, and aircraft noise. The present study investigates if the same ranking can be found for annoyance to nocturnal exposure and next day cognitive performance. Annoyance ratings and performance change during combined noise exposure were also tested. In the laboratory 72 participants were exposed to air, road, or rail traffic noise and all combinations. The number of noise events and LAS,eq were kept constant. Each morning noise annoyance questionnaires and performance tasks were administered. Aircraft noise annoyance ranked first followed by railway and road noise. A possible explanation is the longer duration of aircraft noise events used in this study compared to road and railway noise events. In contrast to road and rail traffic, aircraft noise annoyance was higher after nights with combined exposure. Pooled noise exposure data showed small but significant impairments in reaction times (6 ms) compared to nights without noise. The noise sources did not have a differential impact on performance. Combined exposure to multiple traffic noise sources did not induce stronger impairments than a single noise source. This was reflected also in low workload ratings.

  5. Cold-air performance of a tip turbine designed to drive a lift fan. 3: Effect of simulated fan leakage on turbine performance

    NASA Technical Reports Server (NTRS)

    Haas, J. E.; Kofskey, M. G.; Hotz, G. M.; Futral, S. M., Jr.

    1978-01-01

    Performance data were obtained experimentally for a 0.4 linear scale version of the LF460 lift fan turbine for a range of scroll inlet total to diffuser exit static pressure ratios at design equivalent speed with simulated fan leakage air. Tests were conducted for full and partial admission operation with three separate combinations of rotor inlet and rotor exit leakage air. Data were compared to the results obtained from previous investigations in which no leakage air was present. Results are presented in terms of mass flow, torque, and efficiency.

  6. An All-Solid-State Fiber-Shaped Aluminum-Air Battery with Flexibility, Stretchability, and High Electrochemical Performance.

    PubMed

    Xu, Yifan; Zhao, Yang; Ren, Jing; Zhang, Ye; Peng, Huisheng

    2016-07-04

    Owing to the high theoretical energy density of metal-air batteries, the aluminum-air battery has been proposed as a promising long-term power supply for electronics. However, the available energy density from the aluminum-air battery is far from that anticipated and is limited by current electrode materials. Herein we described the creation of a new family of all-solid-state fiber-shaped aluminum-air batteries with a specific capacity of 935 mAh g(-1) and an energy density of 1168 Wh kg(-1) . The synthesis of an electrode composed of cross-stacked aligned carbon-nanotube/silver-nanoparticle sheets contributes to the remarkable electrochemical performance. The fiber shape also provides the aluminum-air batteries with unique advantages; for example, they are flexible and stretchable and can be woven into a variety of textiles for large-scale applications.

  7. The performance of a mobile air conditioning system with a water cooled condenser

    NASA Astrophysics Data System (ADS)

    Di Battista, Davide; Cipollone, Roberto

    2015-11-01

    Vehicle technological evolution lived, in recent years, a strong acceleration due to the increased awareness of environmental issues related to pollutants and climate altering emissions. This resulted in a series of international regulations on automotive sector which put technical challenges that must consider the engine and the vehicle as a global system, in order to improve the overall efficiency of the system. The air conditioning system of the cabin, for instance, is the one of the most important auxiliaries in a vehicle and requires significant powers. Its performances can be significantly improved if it is integrated within the engine cooling circuit, eventually modified with more temperature levels. In this paper, the Authors present a mathematical model of the A/C system, starting from its single components: compressors, condenser, flush valve and evaporator and a comparison between different refrigerant fluid. In particular, it is introduced the opportunity to have an A/C condenser cooled by a water circuit instead of the external air linked to the vehicle speed, as in the actual traditional configuration. The A/C condenser, in fact, could be housed on a low temperature water circuit, reducing the condensing temperature of the refrigeration cycle with a considerable efficiency increase.

  8. Workplace performance of a loose-fitting powered air purifying respirator during nanoparticle synthesis

    NASA Astrophysics Data System (ADS)

    Koivisto, Antti J.; Aromaa, Mikko; Koponen, Ismo K.; Fransman, Wouter; Jensen, Keld A.; Mäkelä, Jyrki M.; Hämeri, Kaarle J.

    2015-04-01

    Nanoparticle (particles with diameter ≤100 nm) exposure is recognized as a potentially harmful size fraction for pulmonary particle exposure. During nanoparticle synthesis, the number concentrations in the process room may exceed 10 × 106 cm-3. During such conditions, it is essential that the occupants in the room wear highly reliable high-performance respirators to prevent inhalation exposure. Here we have studied the in-use program protection factor (PPF) of loose-fitting powered air purifying respirators, while workers were coating components with TiO2 or Cu x O y nanoparticles under a hood using a liquid flame spray process. The PPF was measured using condensation particle counters, an electrical low pressure impactor, and diffusion chargers. The room particle concentrations varied from 4 × 106 to 40 × 106 cm-3, and the count median aerodynamic diameter ranged from 32 to 180 nm. Concentrations inside the respirator varied from 0.7 to 7.2 cm-3. However, on average, tidal breathing was assumed to increase the respirator concentration by 2.3 cm-3. The derived PPF exceeded 1.1 × 106, which is more than 40 × 103 times the respirator assigned protection factor. We were unable to measure clear differences in the PPF of respirators with old and new filters, among two male and one female user, or assess most penetrating particle size. This study shows that the loose-fitting powered air purifying respirator provides very efficient protection against nanoparticle inhalation exposure if used properly.

  9. The DarkSide awakens

    NASA Astrophysics Data System (ADS)

    Davini, S.; Agnes, P.; Agostino, L.; Albuquerque, I. F. M.; Alexander, T.; Alton, A. K.; Arisaka, K.; Back, H. O.; Baldin, B.; Biery, K.; Bonfini, G.; Bossa, M.; Bottino, B.; Brigatti, A.; Brodsky, J.; Budano, F.; Bussino, S.; Cadeddu, M.; Cadonati, L.; Cadoni, M.; Calaprice, F.; Canci, N.; Candela, A.; Cao, H.; Cariello, M.; Carlini, M.; Catalanotti, S.; Cavalcante, P.; Chepurnov, A.; Cocco, A. G.; Covone, G.; D'Angelo, D.; D'Incecco, M.; De Cecco, S.; De Deo, M.; De Vincenzi, M.; Derbin, A.; Devoto, A.; Di Eusanio, F.; Di Pietro, G.; Edkins, E.; Empl, A.; Fan, A.; Fiorillo, G.; Fomenko, K.; Foster, G.; Franco, D.; Gabriele, F.; Galbiati, C.; Giganti, C.; Goretti, A. M.; Granato, F.; Grandi, L.; Gromov, M.; Guan, M.; Guardincerri, Y.; Hackett, B. R.; Herner, K. R.; Hungerford, E. V.; Ianni, Aldo; Ianni, Andrea; James, I.; Jollet, C.; Keeter, K.; Kendziora, C. L.; Kobychev, V.; Koh, G.; Korablev, D.; Korga, G.; Kubankin, A.; Li, X.; Lissia, M.; Lombardi, P.; Luitz, S.; Ma, Y.; Machulin, I. N.; Mandarano, A.; Mari, S. M.; Maricic, J.; Marini, L.; Martoff, C. J.; Meregaglia, A.; Meyers, P. D.; Miletic, T.; Milincic, R.; Montanari, D.; Monte, A.; Montuschi, M.; Monzani, M. E.; Mosteiro, P.; Mount, B. J.; Muratova, V. N.; Musico, P.; Napolitano, J.; Orsini, M.; Ortica, F.; Pagani, L.; Pallavicini, M.; Pantic, E.; Parmeggiano, S.; Pelczar, K.; Pelliccia, N.; Perasso, S.; Pocar, A.; Pordes, S.; Pugachev, D. A.; Qian, H.; Randle, K.; Ranucci, G.; Razeto, A.; Reinhold, B.; Renshaw, A. L.; Romani, A.; Rossi, B.; Rossi, N.; Rountree, S. D.; Sablone, D.; Saggese, P.; Saldanha, R.; Sands, W.; Sangiorgio, S.; Savarese, C.; Segreto, E.; Semenov, D. A.; Shields, E.; Singh, P. N.; Skorokhvatov, M. D.; Smirnov, O.; Sotnikov, A.; Stanford, C.; Suvorov, Y.; Tartaglia, R.; Tatarowicz, J.; Testera, G.; Tonazzo, A.; Trinchese, P.; Unzhakov, E. V.; Vishneva, A.; Vogelaar, B.; Wada, M.; Walker, S.; Wang, H.; Wang, Y.; Watson, A. W.; Westerdale, S.; Wilhelmi, J.; Wojcik, M. M.; Xiang, X.; Xu, J.; Yang, C.; Yoo, J.; Zavatarelli, S.; Zec, A.; Zhong, W.; Zhu, C.; Zuzel, G.

    2016-05-01

    The DarkSide program at LNGS aims to perform background-free WIMP searches using two phase liquid argon time projection chambers, with the ultimate goal of covering all parameters down to the so-called neutrino floor. One of the distinct features of the program is the use of underground argon with has a reduced content of the radioactive 39Ar compared to atmospheric argon. The DarkSide Collaboration is currently operating the DarkSide-50 experiment, the first such WIMP detector using underground argon. Operations with underground argon indicate a suppression of 39Ar by a factor (1.4 ± 0.2) × 103 relative to atmospheric argon. The new results obtained with DarkSide-50 and the plans for the next steps of the DarkSide program, the 20t fiducial mass DarkSide-20k detector and the 200 t fiducial Argo, are reviewed in this proceedings.

  10. Indoor test for thermal performance evaluation of the Solaron (air) solar collector

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The test procedure used and the results obtained from an evaluation test program, conducted to obtain thermal performance data on a Solaron double glazed air solar collector under simulated conditions in a solar simulator are described. A time constant test and incident angle modifier test were also conducted to determine the transient effect and the incident angle effect on the collector. These results and the results of the collector load test are also discussed. The Solaron collector absorber plate is made of 24-gage steel, the coating is baked-on black paint, the cover consists of two sheets of 1/8-inch low-iron tempered glass, and the insulation is one thickness of 3 5/8-inch fiberglass batting.

  11. Enhanced Component Performance Study: Air-Operated Valves 1998–2013

    SciTech Connect

    Schroeder, John Alton

    2014-10-01

    This report presents a performance evaluation of air-operated valves (AOVs) at U.S. commercial nuclear power plants. The data used in this study are based on the operating experience failure reports from fiscal year 1998 through 2013 for the component reliability as reported in the Institute of Nuclear Power Operations (INPO) Consolidated Events Database (ICES). The AOV failure modes considered are failure-to-open/close, failure to operate or control, and spurious operation. The component reliability estimates and the reliability data are trended for the most recent 10-year period, while yearly estimates for reliability are provided for the entire active period. No statistically significant increasing or decreasing trends were identified in the AOV failure data.

  12. Performance assessment of refractory samples in the Los Alamos Controlled Air Incinerator

    SciTech Connect

    Hutchins, D.A.; Borduin, L.C.; Koenig, R.A.; Vavruska, J.S.; Warner, C.L.

    1986-01-01

    A refractory evaluation project was initiated in 1979 to study the performance of six selected refractory materials within the Los Alamos Controlled Air Incinerator (CAI). Determining refractory resistance to thermal shock, chemical attack, and plutonium uptake was of particular interest. The experimental refractories were subjected to a variety of waste materials, including transuranic (TRU) contaminated wastes, highly chlorinated compounds and alkaline metal salts of perchlorate, chlorate, nitrate and oxylate, over the six year period of this study. Results of this study to date indicate that the use of high alumina, and possibly specialty plastic refractories, is advisable for the lining of incinerators used for the thermal destruction of diverse chemical compounds. 12 refs., 4 tabs.

  13. Design and performance of the Civil Air Patrol ARCHER hyperspectral processing system

    NASA Astrophysics Data System (ADS)

    Stevenson, Brian; O'Connor, Rory; Kendall, William; Stocker, Alan; Schaff, William; Alexa, Drew; Salvador, John; Eismann, Michael; Barnard, Kenneth; Kershenstein, John

    2005-06-01

    The Civil Air Patrol (CAP) is procuring Airborne Real-time Cueing Hyperspectral Enhanced Reconnaissance (ARCHER) systems to increase their search-and-rescue mission capability. These systems are being installed on a fleet of Gippsland GA-8 aircraft, and will position CAP to gain realworld mission experience with the application of hyperspectral sensor and processing technology to search and rescue. The ARCHER system design, data processing, and operational concept leverage several years of investment in hyperspectral technology research and airborne system demonstration programs by the Naval Research Laboratory (NRL) and Air Force Research Laboratory (AFRL). Each ARCHER system consists of a NovaSol-designed, pushbroom, visible/near-infrared (VNIR) hyperspectral imaging (HSI) sensor, a co-boresighted visible panchromatic high-resolution imaging (HRI) sensor, and a CMIGITS-III GPS/INS unit in an integrated sensor assembly mounted inside the GA-8 cabin. ARCHER incorporates an on-board data processing system developed by Space Computer Corporation (SCC) to perform numerous real-time processing functions including data acquisition and recording, raw data correction, target detection, cueing and chipping, precision image geo-registration, and display and dissemination of image products and target cue information. A ground processing station is provided for post-flight data playback and analysis. This paper describes the requirements and architecture of the ARCHER system, with emphasis on data processor design, components, software, interfaces, and displays. Key sensor performance characteristics and real-time data processing features are discussed. The use of the system for detecting and geo-locating ground targets in real-time is demonstrated using test data collected in Southern California in the fall of 2004.

  14. Airborne forward-pointing UV Rayleigh lidar for remote clear air turbulence detection: system design and performance.

    PubMed

    Vrancken, Patrick; Wirth, Martin; Ehret, Gerhard; Barny, Hervé; Rondeau, Philippe; Veerman, Henk

    2016-11-10

    A high-performance airborne UV Rayleigh lidar system was developed within the European project DELICAT. With its forward-pointing architecture, it aims at demonstrating a novel detection scheme for clear air turbulence (CAT) for an aeronautics safety application. Due to its occurrence in clear and clean air at high altitudes (aviation cruise flight level), this type of turbulence evades microwave radar techniques and in most cases coherent Doppler lidar techniques. The present lidar detection technique relies on air density fluctuation measurement and is thus independent of backscatter from hydrometeors and aerosol particles. The subtle air density fluctuations caused by the turbulent air flow demand exceptionally high stability of the setup and in particular of the detection system. This paper describes an airborne test system for the purpose of demonstrating this technology and turbulence detection method: a high-power UV Rayleigh lidar system is installed on a research aircraft in a forward-looking configuration for use in cruise flight altitudes. Flight test measurements demonstrate this unique lidar system being able to resolve air density fluctuations occurring in light-to-moderate CAT at 5 km or moderate CAT at 10 km distance. A scaling of the determined stability and noise characteristics shows that such performance is adequate for an application in commercial air transport.

  15. Performance/design formulation for a solid polymer based acid electrolyte hydrogen/air fuel cell

    NASA Astrophysics Data System (ADS)

    Sandhu, S. S.; Fellner, J. P.

    Mathematical development of preliminary performance/design equations for a hydrogen/air, solid polymer acid electrolyte based fuel cell is presented. The development is based on the principles of transport phenomena, intrinsic electrochemical kinetics, and classical thermodynamics. The developed formulation is intended to quantitatively describe the mass fraction profiles of the chemical species, hydrogen and oxygen, in the cell anode and cathode diffusion and electrocatalytic reaction layers as a function of the distance in the proton transport direction at an axial distance parallel to the cell anode or cathode channel flow. Given the cell geometry, chemical species and charge transport, and intrinsic electrochemical kinetic parameters, the developed formulation can be employed to compute the species local mass fluxes and predict the cell anode and cathode cell overvoltages for a desired geometric current density. The presented single cell performance predictive formulation has also been linked to the formulation needed to predict the performance of a stack of a number of identical PEMFCs connected in series.

  16. Performance of a hydrogen burner to simulate air entering scramjet combustors. [simulation of total temperature, total pressure, and volume fraction of oxygen of air at flight conditions

    NASA Technical Reports Server (NTRS)

    Russin, W. R.

    1974-01-01

    Tests were conducted to determine the performance of a hydrogen burner used to produce a test gas that simulates air entering a scramjet combustor at various flight conditions. The test gas simulates air in that it duplicates the total temperature, total pressure, and the volume fraction of oxygen of air at flight conditions. The main objective of the tests was to determine the performance of the burner as a function of the effective exhaust port area. The conclusions were: (1) pressure oscillations of the chugging type were reduced in amplitude to plus or minus 2 percent of the mean pressure level by proper sizing of hydrogen, oxygen, and air injector flow areas; (2) combustion efficiency remained essentially constant as the exhaust port area was increased by a factor of 3.4; (3) the mean total temperature determined from integrating the exit radial gas property profiles was within plus or minus 5 percent of the theoretical bulk total temperature; (4) the measured exit total temperature profile had a local peak temperature more than 30 percent greater than the theoretical bulk total temperature; and (5) measured heat transfer to the burner liner was 75 percent of that predicted by theory based on a flat radial temperature profile.

  17. Effect of side-stream phosphorus recovery on biological phosphorus removal performance investigated by chemical and microbial analyses in a novel BNR-IC process.

    PubMed

    Zou, H M; Lu, X W; Li, T

    2014-01-01

    The aim of this study was to assess the effect of side-stream ratio (SSR) on performance of phosphorus (P) removal and recovery in a novel process linking biological nutrients removal (BNR) and induced crystallization (IC). Results showed that P removal efficiency was significantly enhanced when given an appropriate SSR, resulting in effluent P concentrations decreasing from 0.75 to 0.39 mg/L with an increase of SSR from 0 to 35%, where a maximum of 7.19 mg/L P recovery amount was obtained at 35% of SSR. Increasing the SSR can favor the P recovery, while an excessively high SSR (more than 35%) would have a negative effect on the subsequent biological P removal in the BNR-IC system. Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) analysis showed that in total, 11 DGGE bands of highest species richness were visually detected and significant changes in microbial community structure were found, with SSR variations ranging from 0 to 55%. Moreover, an increase in SSR can cause an increase in microbial community biodiversity; where microbial populations correspond to the 11 bands, they were generally classified into five different phyla or classes (Beta-, Gamma-, and Deltaproteobacteria, as well as Clostridia and Flavobacteria) based on the evolutionary tree analysis.

  18. Brushless machine having ferromagnetic side plates and side magnets

    DOEpatents

    Hsu, John S

    2012-10-23

    An apparatus is provided having a cylindrical stator and a rotor that is spaced from a stator to define an annular primary air gap that receives AC flux from the stator. The rotor has a plurality of longitudinal pole portions disposed parallel to the axis of rotation and alternating in polarity around a circumference of the rotor. Each longitudinal pole portion includes portions of permanent magnet (PM) material and at least one of the longitudinal pole portions has a first end and an opposing second end and a side magnet is disposed adjacent the first end and a side pole is disposed adjacent the second end.

  19. The contribution of air breathing to aerobic scope and exercise performance in the banded knifefish Gymnotus carapo L.

    PubMed

    McKenzie, David J; Steffensen, John F; Taylor, Edwin W; Abe, Augusto S

    2012-04-15

    The contribution of air breathing to aerobic metabolic scope and exercise performance was investigated in a teleost with bimodal respiration, the banded knifefish, submitted to a critical swimming speed (U(crit)) protocol at 30°C. Seven individuals (mean ± s.e.m. mass 89±7 g, total length 230±4 mm) achieved a U(crit) of 2.1±1 body lengths (BL) s(-1) and an active metabolic rate (AMR) of 350±21 mg kg(-1) h(-1), with 38±6% derived from air breathing. All of the knifefish exhibited a significant increase in air-breathing frequency (f(AB)) with swimming speed. If denied access to air in normoxia, these individuals achieved a U(crit) of 2.0±0.2 BL s(-1) and an AMR of 368±24 mg kg(-1) h(-1) by gill ventilation alone. In normoxia, therefore, the contribution of air breathing to scope and exercise was entirely facultative. In aquatic hypoxia (P(O(2))=4 kPa) with access to normoxic air, the knifefish achieved a U(crit) of 2.0±0.1 BL s(-1) and an AMR of 338±29 mg kg(-1) h(-1), similar to aquatic normoxia, but with 55±5% of AMR derived from air breathing. Indeed, f(AB) was higher than in normoxia at all swimming speeds, with a profound exponential increase during exercise. If the knifefish were denied access to air in hypoxia, U(crit) declined to 1.2±0.1 BL s(-1) and AMR declined to 199±29 mg kg(-1) h(-1). Therefore, air breathing allowed the knifefish to avoid limitations to aerobic scope and exercise performance in aquatic hypoxia.

  20. Performance Analysis and Parametric Study of a Natural Convection Solar Air Heater With In-built Oil Storage

    NASA Astrophysics Data System (ADS)

    Dhote, Yogesh; Thombre, Shashikant

    2016-10-01

    This paper presents the thermal performance of the proposed double flow natural convection solar air heater with in-built liquid (oil) sensible heat storage. Unused engine oil was used as thermal energy storage medium due to its good heat retaining capacity even at high temperatures without evaporation. The performance evaluation was carried out for a day of the month March for the climatic conditions of Nagpur (India). A self reliant computational model was developed using computational tool as C++. The program developed was self reliant and compute the performance parameters for any day of the year and would be used for major cities in India. The effect of change in storage oil quantity and the inclination (tilt angle) on the overall efficiency of the solar air heater was studied. The performance was tested initially at different storage oil quantities as 25, 50, 75 and 100 l for a plate spacing of 0.04 m with an inclination of 36o. It has been found that the solar air heater gives the best performance at a storage oil quantity of 50 l. The performance of the proposed solar air heater is further tested for various combinations of storage oil quantity (50, 75 and 100 l) and the inclination (0o, 15o, 30o, 45o, 60o, 75o, 90o). It has been found that the proposed solar air heater with in-built oil storage shows its best performance for the combination of 50 l storage oil quantity and 60o inclination. Finally the results of the parametric study was also presented in the form of graphs carried out for a fixed storage oil quantity of 25 l, plate spacing of 0.03 m and at an inclination of 36o to study the behaviour of various heat transfer and fluid flow parameters of the solar air heater.

  1. Performance of personal inhalable aerosol samplers in very slowly moving air when facing the aerosol source.

    PubMed

    Witschger, O; Grinshpun, S A; Fauvel, S; Basso, G

    2004-06-01

    than 10 micro m; its efficiency did not exceed 7% for particles of 40-100 micro m. The IOM Sampler facing the source was found to over-sample compared with the data obtained previously with a slowly rotating, freely suspended sampler in a low air movement environment. It was also found that the particle wall deposition in the IOM metallic cartridge was rather significant and particle size-dependent. For each sampler (IOM, Button and C25) the precision was characterized through the relative standard deviation (RSD) of the aerosol concentration obtained with identical samplers in a specific experiment. The average RSD was 14% for the IOM Sampler, 11% for the Button Sampler and 35% for the 25 mm filter cassette. A separate set of experiments, performed with the Simplified Torso showed that in very slowly moving air a personal sampler can be adequately evaluated even when it is not attached to a body but freely suspended (confirming the data reported previously).

  2. Thermodynamic analysis and optimization of air-cooled heat exchangers

    NASA Astrophysics Data System (ADS)

    Salimpour, Mohammad Reza; Bahrami, Zabihollah

    2011-01-01

    In the present study, a thermodynamic second-law analysis was performed to investigate the effects of different geometry and flow parameters on the air-cooled heat exchanger performance. For this purpose, the entropy generation due to heat transfer and pressure loss of internal and external flows of the air-cooled heat exchanger was calculated; and it was observed that the total entropy generation has a minimum at special tube-side Reynolds number. Also, it was seen that the increasing of the tube-side Reynolds number resulted in the rise of the irreversibility of the air-cooled heat exchanger. The results also showed when air-side Reynolds number decreased, the entropy generation rate of the external flow reduced. Finally, based on the computed results, a new correlation was developed to predict the optimum Reynolds number of the tube-side fluid flow.

  3. Indoor air quality in 24 California residences designed as high-performance homes

    SciTech Connect

    Less, Brennan; Mullen, Nasim; Singer, Brett; Walker, Iain

    2015-01-01

    Today’s high performance green homes are reaching previously unheard of levels of airtightness and are using new materials, technologies and strategies, whose impacts on Indoor Air Quality (IAQ) cannot be fully anticipated from prior studies. This research study used pollutant measurements, home inspections, diagnostic testing and occupant surveys to assess IAQ in 24 new or deeply retrofitted homes designed to be high performance green buildings in California. Although the mechanically vented homes were six times as airtight as non-mechanically ventilated homes (medians of 1.1 and 6.1 ACH50, n=11 and n=8, respectively), their use of mechanical ventilation systems and possibly window operation meant their median air exchange rates were almost the same (0.30 versus 0.32 hr-1, n=8 and n=8, respectively). Pollutant levels were also similar in vented and unvented homes. In addition, these similarities were achieved despite numerous observed faults in complex mechanical ventilation systems. More rigorous commissioning is still recommended. Cooking exhaust systems were used inconsistently and several suffered from design flaws. Failure to follow best practices led to IAQ problems in some cases. Ambient nitrogen dioxide standards were exceeded or nearly so in four homes that either used gas ranges with standing pilots, or in Passive House-style homes that used gas cooking burners without venting range hoods. Homes without active particle filtration had particle count concentrations approximately double those in homes with enhanced filtration. The majority of homes reported using low-emitting materials; consistent with this, formaldehyde levels were approximately half those in conventional, new CA homes built before 2008. Emissions of ultrafine particles (with diameters <100 nm) were dramatically lower on induction electric cooktops, compared with either gas or resistance electric models. These results indicate that high performance homes can achieve

  4. Interim Report: Air-Cooled Condensers for Next Generation Geothermal Power Plants Improved Binary Cycle Performance

    SciTech Connect

    Daniel S. Wendt; Greg L. Mines

    2010-09-01

    As geothermal resources that are more expensive to develop are utilized for power generation, there will be increased incentive to use more efficient power plants. This is expected to be the case with Enhanced Geothermal System (EGS) resources. These resources will likely require wells drilled to depths greater than encountered with hydrothermal resources, and will have the added costs for stimulation to create the subsurface reservoir. It is postulated that plants generating power from these resources will likely utilize the binary cycle technology where heat is rejected sensibly to the ambient. The consumptive use of a portion of the produced geothermal fluid for evaporative heat rejection in the conventional flash-steam conversion cycle is likely to preclude its use with EGS resources. This will be especially true in those areas where there is a high demand for finite supplies of water. Though they have no consumptive use of water, using air-cooling systems for heat rejection has disadvantages. These systems have higher capital costs, reduced power output (heat is rejected at the higher dry-bulb temperature), increased parasitics (fan power), and greater variability in power generation on both a diurnal and annual basis (larger variation in the dry-bulb temperature). This is an interim report for the task ‘Air-Cooled Condensers in Next- Generation Conversion Systems’. The work performed was specifically aimed at a plant that uses commercially available binary cycle technologies with an EGS resource. Concepts were evaluated that have the potential to increase performance, lower cost, or mitigate the adverse effects of off-design operation. The impact on both cost and performance were determined for the concepts considered, and the scenarios identified where a particular concept is best suited. Most, but not all, of the concepts evaluated are associated with the rejection of heat. This report specifically addresses three of the concepts evaluated: the use of

  5. The effect of low ventilation rate with elevated bioeffluent concentration on work performance, perceived indoor air quality and health symptoms.

    PubMed

    Maula, Henna; Hongisto, Valtteri; Naatula, Viivi; Haapakangas, Annu; Koskela, Hannu

    2017-04-05

    The aim of this laboratory experiment was to study the effects of ventilation rate, and related changes in air quality, predominantly bioeffluents, on work performance, perceived indoor air quality and health symptoms in a typical conditions of modern open-plan office with low material and equipment emissions. In Condition A, outdoor air flow rate of 28.2 l/s person (CO2 level 540 ppm) was applied and in Condition B, outdoor air flow rate was 2.3 l/s person (CO2 level 2260 ppm). CO2 concentration level was used as an indicator of bioeffluents. Performance was measured with seven different tasks which measure different cognitive processes. Thirty-six subjects participated in the experiment. The exposure time was 4 hours. Condition B had a weak negative effect on performance only in the information retrieval tasks. Condition B increased slightly subjective workload and perceived fatigue. No effects on health symptoms were found. The intensity of symptoms was low in both conditions. The experimental condition had an effect on perceived air quality and observed odour intensity only in the beginning of the session. Although the room temperature was controlled in both conditions, the heat was perceived to impair the performance more in Condition B. This article is protected by copyright. All rights reserved.

  6. Performance characteristics of a turbo expander substituted for expansion valve on air-conditioner

    SciTech Connect

    Cho, Soo-Yong; Cho, Chong-Hyun; Kim, Chaesil

    2008-09-15

    An experimental study is conducted on a small turbo expander which could be applied to the expansion process in place of expansion valves in refrigerator or air-conditioner to improve the cycle efficiency by recovering energy from the throttling process. The operating gas is HFC134a and the maximum cooling capacity of experiment apparatus is 32.7 kW. Four different turbo expanders are tested to find the performance characteristics of the turbo expander when they operate at a low partial admission rate. The partial admission rate is 1.70% or 2.37, and expanders are operated in the supersonic flow. In the experiment, pressure and temperature are measured at 10 different locations in the experimental apparatus. In addition to these measurements, output power at the turbo expander is measured through a generator installed on a rotor shaft with the rotational speed. Performance data of the turbo expander are obtained at many part load operations by adjusting the output power of the generator. A maximum of 15.8% total-to-static efficiency is obtained when the pressure ratio and the partial admission ratio are 2.37 and 1.70%, respectively. Experimental results show that the optimal velocity ratio decreases when the pressure ratio is decreased, and peak efficiencies, which are obtained at locally maximized efficiency depending on the operating condition, vary linearly against the subcooling temperature or the pressure ratio. (author)

  7. Performance and Durability of High Temperature Foil Air Bearing for Oil-Free Turbomachinery

    NASA Technical Reports Server (NTRS)

    DellaCorte, C.; Valco, M. J.; Radil, K. C.; Heshmat, H.

    1999-01-01

    The performance and durability of advanced, high temperature foil air bearings are evaluated under a wide range (10-50 kPa) of loads at temperatures from 25 to 650 C. The bearings are made from uncoated nickel based superalloy foils. The foil surface experiences sliding contact with the shaft during initial start/stop operation. To reduce friction and wear, the solid lubricant coating, PS304, is applied to the shaft by plasma spraying. PS304, is a NiCr based Cr2O3 coating with silver and barium fluoride/calcium fluoride solid lubricant additions. The results show that the bearings provide lives well in excess of 30,000 cycles under all of the conditions tested. Several bearings exhibited lives in excess of 100,000 cycles. Wear is a linear function of the bearing load. The excellent performance measured in this study suggests that these bearings and the PS304 coating are well suited for advanced high temperature, oil-free turbomachinery applications.

  8. Design and performance of an axial air-gap solution pump motor

    NASA Astrophysics Data System (ADS)

    Hawsey, R. A.; Sohns, C. W.; Daniel, D. S.; Bailey, J. M.

    1990-05-01

    An axial air gap, permanent magnet, brushless dc motor was designed and was evaluated on a dynamometer to measure operating characteristics. The motor must deliver 0.167 hp (approx. 120 W) to the pump rotor at 1800 rpm. Initial performance data with a half-bridge, Hall-probe synchronized drive system and a dry motor bearing did not achieve the desired motor performance. Subsequently, a commercial full-bridge, speed regulated sensorless drive system was used to test the motor. The motor delivered the required 90 oz-in. of torque at 1800 rpm. These data revealed the need for rewinding the stator core to improve motor efficiency. A second stator core, with deeper slots and additional turns of wire, was subsequently fabricated and tested. At 1800 rpm, the drive system could produce only 60 oz-in. of torque due to an unexpectedly high generated voltage. Motor efficiency was 60 to 70 pct. at this torque level when the data were corrected for bearing and coupling drag.

  9. Comparative Cooling Season Performance of Air Distribution Systems in Multistory Townhomes

    SciTech Connect

    Poerschke, Andrew; Beach, Rob; Beggs, Timothy

    2016-08-01

    IBACOS investigated the performance of a small-diameter high velocity heat pump system compared to a conventional system in a new construction triplex townhouse. A ductless heat pump system also was installed for comparison, but the homebuyer backed out because of aesthetic concerns about that system. In total, two buildings, having identical solar orientation and comprised of six townhomes, were monitored for comfort and energy performance. Results show that the small-diameter system provides more uniform temperatures from floor to floor in the three-story townhome. No clear energy consumption benefit was observed from either system. The builder is continuing to explore the small-diameter system as its new standard system to provide better comfort and indoor air quality. The homebuilder also explored the possibility of shifting its townhome product to meet the U.S. Department of Energy Challenge Home National Program Requirements. Ultimately, the builder decided that adoption of these practices would be too disruptive midstream in the construction cycle. However, the townhomes met the ENERGY STAR Version 3.0 program requirements.

  10. Performance and microbial ecology of air-cathode microbial fuel cells with layered electrode assemblies.

    PubMed

    Butler, Caitlyn S; Nerenberg, Robert

    2010-05-01

    Microbial fuel cells (MFCs) can be built with layered electrode assemblies, where the anode, proton exchange membrane (PEM), and cathode are pressed into a single unit. We studied the performance and microbial community structure of MFCs with layered assemblies, addressing the effect of materials and oxygen crossover on the community structure. Four MFCs with layered assemblies were constructed using Nafion or Ultrex PEMs and a plain carbon cloth electrode or a cathode with an oxygen-resistant polytetrafluoroethylene diffusion layer. The MFC with Nafion PEM and cathode diffusion layer achieved the highest power density, 381 mW/m(2) (20 W/m(3)). The rates of oxygen diffusion from cathode to anode were three times higher in the MFCs with plain cathodes compared to those with diffusion-layer cathodes. Microsensor studies revealed little accumulation of oxygen within the anode cloth. However, the abundance of bacteria known to use oxygen as an electron acceptor, but not known to have exoelectrogenic activity, was greater in MFCs with plain cathodes. The MFCs with diffusion-layer cathodes had high abundance of exoelectrogenic bacteria within the genus Geobacter. This work suggests that cathode materials can significantly influence oxygen crossover and the relative abundance of exoelectrogenic bacteria on the anode, while PEM materials have little influence on anode community structure. Our results show that oxygen crossover can significantly decrease the performance of air-cathode MFCs with layered assemblies, and therefore limiting crossover may be of particular importance for these types of MFCs.

  11. Perpetual factors involved in performance of air traffic controllers using a microwave landing system

    NASA Technical Reports Server (NTRS)

    Gershzohn, G.

    1978-01-01

    The task involved the control of two simulated aircraft targets per trial, in a 37.0 -km radius terminal area, by means of conventional radar vectoring and/or speed control. The goal was to insure that the two targets crossed the Missed Approach Point (MAP) at the runway threshold exactly 60 sec apart. The effects on controller performance of the MLS configuration under wind and no-wind conditions were examined. The data for mean separation time between targets at the MAP and the range about that mean were analyzed by appropriate analyses of variance. Significant effects were found for mean separation times as a result of the configuration of the MLS and for interaction between the configuration and wind conditions. The analysis of variance for range indicated significantly poorer performance under the wind condition. These findings are believed to be a result of certain perceptual factors involved in radar air traffic control (ATC) using the MLS with separation of targets in time.

  12. Enhanced Component Performance Study: Air-Operated Valves 1998–2012

    SciTech Connect

    T. E. Wierman

    2013-10-01

    This report presents an enhanced performance evaluation of air-operated valves (AOVs) at U.S. commercial nuclear power plants. The data used in this study are based on the operating experience failure reports from fiscal year 1998 through 2012 for the component reliability as reported in the Equipment Performance and Information Exchange (EPIX). Results (beta distributions for failure probabilities upon demand and gamma distributions for rates) are used as inputs to the U.S. Nuclear Regulatory Commission standardized plant analysis risk models of U.S. commercial nuclear power plants. The AOV failure modes considered are failure-to-open/close, failure to operate or control, and spurious operation. The component reliability estimates and the reliability data are trended for the most recent 10-year period while yearly estimates for reliability are provided for the entire active period. No statistically significant increasing trends were identified in the AOV results. Statistically significant decreasing trends were identified in two areas: AOV operation demands less than or equal to 20 demands per year and greater than 20 demands.

  13. Improved performance of air-cathode microbial fuel cell through additional Tween 80

    NASA Astrophysics Data System (ADS)

    Wen, Qing; Kong, Fanying; Ma, Fang; Ren, Yueming; Pan, Zhongcheng

    The ability of electron transfer from microbe cell to anode electrode plays a key role in microbial fuel cell (MFC). This study explores a new approach to improve the MFC performance and electron transfer rate through addition of Tween 80. Results demonstrate that, for an air-cathode MFC operating on 1 g L -1 glucose, when the addition of Tween 80 increases from 0 to 80 mg L -1, the maximum power density increases from 21.5 to 187 W m -3 (0.6-5.2 W m -2), the corresponding current density increases from 1.8 to 17 A m -2, and the resistance of MFC decreases from 27.0 to 5.7 Ω. Electrochemical impedance spectroscopy (EIS) analysis suggests that the improvement of overall performance of the MFC can be attributed to the addition of Tween 80. The high power density achieved here may be due to the increase of permeability of cell membranes by addition of Tween 80, which reduces the electron transfer resistance through the cell membrane and increases the electron transfer rate and number, consequently enhances the current and power output. A promising way of utilizing surfactant to improve energy generation of MFC is demonstrated.

  14. Performance and Durability of High Temperature Foil Air Bearings for Oil-Free Turbomachinery

    NASA Technical Reports Server (NTRS)

    DellaCorte, C.; Lukaszewicz, V.; Valco, M. J.; Radil, K. C.; Heshmat, H.

    2000-01-01

    The performance and durability of advanced, high temperature foil air bearings are evaluated under a wide range (10-50 kPa) of loads at temperatures from 25 to 650 C. The bearings are made from uncoated nickel based superalloy foils. The foil surface experiences sliding contact with the shaft during initial start/stop operation. To reduce friction and wear, the solid lubricant coating, PS304, is applied to the shaft by plasma spraying. PS304 is a NiCr based Cr2O3 coating with silver and barium fluoride/calcium fluoride solid lubricant additions. The results show that the bearings provide lives well in excess of 30,000 cycles under all of the conditions tested. Several bearings exhibited lives in excess of 100,000 cycles. Wear is a linear function of the bearing load. The excellent performance measured in this study suggests that these bearings and the PS304 coating are well suited for advanced high temperature, oil-free turbomachinery applications.

  15. Optimization of Ventilation Energy Demands and Indoor Air Quality in High-Performance Homes

    SciTech Connect

    Hun, Diana E; Jackson, Mark C; Shrestha, Som S

    2014-01-01

    High-performance homes require that ventilation energy demands and indoor air quality (IAQ) be simultaneously optimized. We attempted to bridge these two areas by conducting tests in a research house located in Oak Ridge, TN, that was 20 months old, energy-efficient (i.e., expected to consume 50% less energy than a house built per the 2006 IRC), tightly-built (i.e., natural ventilation rate ~0.02 h-1), unoccupied, and unfurnished. We identified air pollutants of concern in the test home that could generally serve as indicators of IAQ, and conduced field experiments and computer simulations to determine the effectiveness and energy required by various techniques that lessened the concentration of these contaminants. Formaldehyde was selected as the main pollutant of concern among the contaminants that were sampled in the initial survey because it was the only compound that showed concentrations that were greater than the recommended exposure levels. Field data indicate that concentrations were higher during the summer primarily because emissions from sources rise with increases in temperature. Furthermore, supply ventilation and gas-phase filtration were effective means to reduce formaldehyde concentrations; however, exhaust ventilation had minimal influence on this pollutant. Results from simulations suggest that formaldehyde concentrations obtained while ventilating per ASHRAE 62.2-2010 could be decreased by about 20% from May through September through three strategies: 1) increasing ASHRAE supply ventilation by a factor of two, 2) reducing the thermostat setpoint from 76 to 74 F, or 3) running a gas-phase filtration system while decreasing supply ventilation per ASHRAE by half. In the mixed-humid climate of Oak Ridge, these strategies caused increases in electricity cost of ~$5 to ~$15/month depending on outdoor conditions.

  16. Reproductive performance of dairy farms in western Buenos Aires province, Argentina.

    PubMed

    Ferreira, Gonzalo

    2013-01-01

    The objective of this study was to describe the reproductive performance of 23 grazing-based dairy farms from western Buenos Aires province in Argentina. The data set included data from the breeding season starting in May 2011 and ending in March 2012. Submission, conception, and pregnancy rates ranged from 42.4 to 70.2%, 20.1 to 44.9%, and 10.3 to 24.5%, respectively. No correlation was observed between conception and submission rates, suggesting that dairy farms with poor submission rates but with relatively high conception rates might increase pregnancy rates by simply putting more effort into increasing estrus detection and submission rates. Decreases in submission and conception rates were observed among 21-d cycles, indicating seasonal variation. A greater number of cows in estrus at the beginning of the breeding period could have facilitated estrus detection and therefore increased submission rates. In addition, restarting the breeding activities with timed artificial insemination programs may explain the highest submission rates at the beginning of the breeding period. A first decrease of 5.1 percentage units in conception rate was observed during the spring (October-November) and an additional decrease of 2.4 percentage units in conception rate was observed during the summer (January-February). Decreases in conception rates could be related to high intakes of high-protein diets, heat stress, or a combination of both. Attenuating heat stress during the summer may be critical for maximizing conception rates in grazing systems from western Buenos Aires province.

  17. Design and Performance of a Gas Chromatograph for Automatic Monitoring of Pollutants in Ambient Air

    NASA Technical Reports Server (NTRS)

    Villalobos, R.; Stevens, D.; LeBlanc, R.; Braun, L.

    1971-01-01

    In recent years, interest in air pollution constituents has focused on carbon monoxide and hydrocarbons as prime components of polluted air. Instrumental methods have been developed, and commercial instruments for continuous monitoring of these components have been available for a number of years. For the measurement of carbon monoxide, non-dispersive infrared spectroscopy has been the accepted tool, in spite of its marginal sensitivity at low parts-per-million levels. For continuously monitoring total hydrocarbons, the hydrogen flame ionization analyzer has been widely accepted as the preferred method. The inadequacy of this latter method became evident when it was concluded that methane is non-reactive and cannot be considered a contaminant even though present at over 1 ppm in the earth's atmosphere. Hence, the need for measuring methane separately became apparent as a means of measuring the reactive and potentially harmful non-methane hydrocarbons fraction. A gas chromatographic method for the measurement of methane and total hydrocarbons which met these requirements has been developed. In this technique, methane was separated on conventional gas chromatographic columns and detected by a hydrogen flame ionization detector (FID) while the total hydrocarbons were obtained by introducing a second sample directly into the FID without separating the various components. The reactive, or non-methane hydrocarbons, were determined by difference. Carbon monoxide was also measured after converting to methane over a heated catalyst to render it detectable by the FID. The development of this method made it possible to perform these measurements with a sensitivity of as much as 1 ppm full scale and a minimum detectability of 20 ppb. Incorporating this technique, criteria were developed by APCO for a second generation continuous automatic instrument for atmospheric monitoring stations.

  18. NORTH SIDE FACING TRACK, SHOWING ELECTRICAL BOX AND CONCRETE VAULT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    NORTH SIDE FACING TRACK, SHOWING ELECTRICAL BOX AND CONCRETE VAULT - Edwards Air Force Base, South Base Sled Track, Electrical Distribution Station, South side of Sled Track, Lancaster, Los Angeles County, CA

  19. Encouraging overweight students with intellectual disability to actively perform walking activity using an air mouse combined with preferred stimulation.

    PubMed

    Chang, Chia-Jui; Chang, Man-Ling; Shih, Ching-Hsiang

    2016-08-01

    This study continues the research on using an air mouse as a physical activity detector. An air mouse is embedded with a MEMS (Micro Electro Mechanical Systems) gyro sensor, which can measure even the slightest movement in the air. The air mouse was strapped to one of each participant's calves to detect walking activity. This study was conducted to evaluate whether four students with intellectual disability who were overweight and disliked exercising could be motivated to engage in walking actively by linking the target response with preferred stimulation. Single-subject research with ABAB design was adopted in this study. The experimental data showed substantial increases in the participants' target responses (i.e. the performance of the activity of walking) during the intervention phases compared to the baseline phases. The practical and developmental implications of the findings are discussed.

  20. Natural Flow Air Cooled Photovoltaics

    NASA Astrophysics Data System (ADS)

    Tanagnostopoulos, Y.; Themelis, P.

    2010-01-01

    Our experimental study aims to investigate the improvement in the electrical performance of a photovoltaic installation on buildings through cooling of the photovoltaic panels with natural air flow. Our experimental study aims to investigate the improvement in the electrical performance of a photovoltaic installation on buildings through cooling of the photovoltaic panels with natural air flow. We performed experiments using a prototype based on three silicon photovoltaic modules placed in series to simulate a typical sloping building roof with photovoltaic installation. In this system the air flows through a channel on the rear side of PV panels. The potential for increasing the heat exchange from the photovoltaic panel to the circulating air by the addition of a thin metal sheet (TMS) in the middle of air channel or metal fins (FIN) along the air duct was examined. The operation of the device was studied with the air duct closed tightly to avoid air circulation (CLOSED) and the air duct open (REF), with the thin metal sheet (TMS) and with metal fins (FIN). In each case the experiments were performed under sunlight and the operating parameters of the experimental device determining the electrical and thermal performance of the system were observed and recorded during a whole day and for several days. We collected the data and form PV panels from the comparative diagrams of the experimental results regarding the temperature of solar cells, the electrical efficiency of the installation, the temperature of the back wall of the air duct and the temperature difference in the entrance and exit of the air duct. The comparative results from the measurements determine the improvement in electrical performance of the photovoltaic cells because of the reduction of their temperature, which is achieved by the naturally circulating air.

  1. Performance of a Compression-ignition Engine with a Precombustion Chamber Having High-Velocity Air Flow

    NASA Technical Reports Server (NTRS)

    Spanogle, J A; Moore, C S

    1931-01-01

    Presented here are the results of performance tests made with a single-cylinder, four stroke cycle, compression-ignition engine. These tests were made on a precombustion chamber type of cylinder head designed to have air velocity and tangential air flow in both the chamber and cylinder. The performance was investigated for variable load and engine speed, type of fuel spray, valve opening pressure, injection period and, for the spherical chamber, position of the injection spray relative to the air flow. The pressure variations between the pear-shaped precombustion chamber and the cylinder for motoring and full load conditions were determined with a Farnboro electric indicator. The combustion chamber designs tested gave good mixing of a single compact fuel spray with the air, but did not control the ensuing combustion sufficiently. Relative to each other, the velocity of air flow was too high, the spray dispersion by injection too great, and the metering effect of the cylinder head passage insufficient. The correct relation of these factors is of the utmost importance for engine performance.

  2. Thermal performance evaluation of MSFC hot air collectors with various flow channel depth

    NASA Technical Reports Server (NTRS)

    1979-01-01

    The test procedures used and the results obtained during the evaluation test program on the MSFC air collector with flow channel depth of 3 in., 2 in., and 1 in., under simulated conditions are presented. The MSFC hot air collector consists of a single glass cover with a nonselective coating absorber plate and uses air as the heat transfer medium. The absorber panel consists of a thin flat sheet of aluminum.

  3. Air Force Science & Technology Issues & Opportunities Regarding High Performance Embedded Computing

    DTIC Science & Technology

    2009-09-23

    Challenges by Domain * Air: Persistent air dominance is at risk * Increasingly effective air defenses * Proliferation of 5th generation fighters, cheap cruise missiles, and UASs * Light-speed war possibilities are terrifying * Space: Now a contested domain * Increasingly important * Increasingly vulnerable * Cyber: Cyber warfare has begun * We don’t control the battlespace * We rely on it more and more * We can’t find the enemy.

  4. Gradient porous electrode architectures for rechargeable metal-air batteries

    DOEpatents

    Dudney, Nancy J.; Klett, James W.; Nanda, Jagjit; Narula, Chaitanya Kumar; Pannala, Sreekanth

    2016-03-22

    A cathode for a metal air battery includes a cathode structure having pores. The cathode structure has a metal side and an air side. The porosity decreases from the air side to the metal side. A metal air battery and a method of making a cathode for a metal air battery are also disclosed.

  5. Beneficial effects of air inclusions on the performance of ethylene vinyl acetate (EVA) mouthguard material

    PubMed Central

    Westerman, B; Stringfellow, P; Eccleston, J

    2002-01-01

    Objective: To investigate the impact characteristics of an ethylene vinyl acetate (EVA) mouthguard material with regulated air inclusions, which included various air cell volumes and wall thickness between air cells. In particular, the aim was to identify the magnitude and direction of forces within the impacts. Method: EVA mouthguard material, 4 mm thick and with and without air inclusions, was impacted with a constant force impact pendulum with an energy of 4.4 J and a velocity of 3 m/s. Transmitted forces through the EVA material were measured using an accelerometer, which also allowed the determination of force direction and magnitude within the impacts. Results: Statistically significant reductions in the transmitted forces were observed with all the air inclusion materials when compared with EVA without air inclusions. Maximum transmitted force through one air inclusion material was reduced by 32%. Force rebound was eliminated in one material, and reduced second force impulses were observed in all the air inclusion materials. Conclusion: The regulated air inclusions improved the impact characteristics of the EVA mouthguard material, the material most commonly used in mouthguards world wide. PMID:11867493

  6. The impact of air-fuel mixture composition on SI engine performance during natural gas and producer gas combustion

    NASA Astrophysics Data System (ADS)

    Przybyła, G.; Postrzednik, S.; Żmudka, Z.

    2016-09-01

    The paper summarizers results of experimental tests of SI engine fuelled with gaseous fuels such as, natural gas and three mixtures of producer gas substitute that simulated real producer gas composition. The engine was operated under full open throttle and charged with different air-fuel mixture composition (changed value of air excess ratio). The spark timing was adjusted to obtain maximum brake torque (MBT) for each fuel and air-fuel mixture. This paper reports engine indicated performance based on in-cylinder, cycle resolved pressure measurements. The engine performance utilizing producer gas in terms of indicated efficiency is increased by about 2 percentage points when compared to fuelling with natural gas. The engine power de-rating when producer gas is utilized instead the natural gas, varies from 24% to 28,6% under stoichiometric combustion conditions. For lean burn (λ=1.5) the difference are lower and varies from 22% to 24.5%.

  7. Significant Improvement of Semiconducting Performance of the Diketopyrrolopyrrole-Quaterthiophene Conjugated Polymer through Side-Chain Engineering via Hydrogen-Bonding.

    PubMed

    Yao, Jingjing; Yu, Chenmin; Liu, Zitong; Luo, Hewei; Yang, Yang; Zhang, Guanxin; Zhang, Deqing

    2016-01-13

    Three diketopyrrolopyrrole (DPP)-quaterthiophene conjugated polymers, pDPP4T-1, pDPP4T-2, and pDPP4T-3, in which the molar ratios of the urea-containing alkyl chains vs branching alkyl chains are 1:30, 1:20, and 1:10, respectively, were prepared and investigated. In comparison with pDPP4T without urea groups in the alkyl side chains and pDPP4T-A, pDPP4T-B, and pDPP4T-C containing both linear and branched alkyl chains, thin films of pDPP4T-1, pDPP4T-2, and pDPP4T-3 exhibit higher hole mobilities; thin-film mobility increases in the order pDPP4T-1 < pDPP4T-2 < pDPP4T-3, and hole mobility of a thin film of pDPP4T-3 can reach 13.1 cm(2) V(-1) s(-1) after thermal annealing at just 100 °C. The incorporation of urea groups in the alkyl side chains also has an interesting effect on the photovoltaic performances of DPP-quaterthiophene conjugated polymers after blending with PC71BM. Blended thin films of pDPP4T-1:PC71BM, pDPP4T-2:PC71BM, and pDPP4T-3:PC71BM exhibit higher power conversion efficiencies (PCEs) than pDPP4T:PC71BM, pDPP4T-A:PC71BM, pDPP4T-B:PC71BM, and pDPP4T-C:PC71BM. The PCE of pDPP4T-1:PC71BM reaches 6.8%. Thin films of pDPP4T-1, pDPP4T-2, and pDPP4T-3 and corresponding thin films with PC71BM were characterized with AFM, GIXRD, and STEM. The results reveal that the lamellar packing order of the alkyl chains is obviously enhanced for thin films of pDPP4T-1, pDPP4T-2, and pDPP4T-3; after thermal annealing, slight inter-chain π-π stacking emerges for pDPP4T-2 and pDPP4T-3. Blends of pDPP4T-1, pDPP4T-2, and pDPP4T-3 with PC71BM show a more pronounced micro-phase separation. These observations suggest that the presence of urea groups may further facilitate the assemblies of these conjugated polymers into nanofibers and ordered aggregation of PC71BM.

  8. Air Traffic Controller Performance and Acceptability of Multiple UAS in a Simulated NAS Environment

    NASA Technical Reports Server (NTRS)

    Vu, Kim-Phuong L.; Strybel, Thomas; Chiappe, Dan; Morales, Greg; Battiste, Vernol; Shively, Robert Jay

    2014-01-01

    Previously, we showed that air traffic controllers (ATCos) rated UAS pilot verbal response latencies as acceptable when a 1.5 s delay was added to the UAS pilot responses, but a 5 s delay was rated as mostly unacceptable. In the present study we determined whether a 1.5 s added delay in the UAS pilots' verbal communications would affect ATCos interactions with UAS and other conventional aircraft when the number and speed of the UAS were manipulated. Eight radar-certified ATCos participated in this simulation. The ATCos managed a medium altitude sector containing arrival aircraft, en route aircraft, and one to four UAS. The UAS were conducting a surveillance mission and flew at either a "slow" or "fast" speed. We measured both UAS and conventional pilots' verbal communication latencies, and obtained ATCos' acceptability ratings for these latencies. Although the UAS pilot response latencies were longer than those of conventional pilots, the ATCos rated UAS pilot verbal communication latencies to be as acceptable as those of conventional pilots. Because the overall traffic load within the sector was held constant, ATCos only performed slightly worse when multiple UAS were in their sector compared to when only one UAS was in the sector. Implications of these findings for UAS integration in the NAS are discussed.

  9. Enhanced Component Performance Study: Air-Operated Valves 1998-2014

    SciTech Connect

    Schroeder, John Alton

    2015-11-01

    This report presents a performance evaluation of air-operated valves (AOVs) at U.S. commercial nuclear power plants. The data used in this study are based on the operating experience failure reports from fiscal year 1998 through 2014 for the component reliability as reported in the Institute of Nuclear Power Operations (INPO) Consolidated Events Database (ICES). The AOV failure modes considered are failure-to-open/close, failure to operate or control, and spurious operation. The component reliability estimates and the reliability data are trended for the most recent 10-year period, while yearly estimates for reliability are provided for the entire active period. One statistically significant trend was observed in the AOV data: The frequency of demands per reactor year for valves recording the fail-to-open or fail-to-close failure modes, for high-demand valves (those with greater than twenty demands per year), was found to be decreasing. The decrease was about three percent over the ten year period trended.

  10. Air Launch: Examining Performance Potential of Various Configurations and Growth Options

    NASA Technical Reports Server (NTRS)

    Waters, Eric D.; Creech, Dennis M.; Philips, Alan D.

    2013-01-01

    The Advanced Concepts Office at NASA's George C. Marshall Space Flight Center conducted a high-level analysis of various air launch vehicle configurations, objectively determining maximum launch vehicle payload while considering carrier aircraft capabilities and given dimensional constraints. With the renewed interest in aerial launch of low-earth orbit payloads, referenced by programs such as Stratolaunch and Spaceship2, there exists a need to qualify the boundaries of the trade space, identify performance envelopes, and understand advantages and limiting factors of designing for maximum payload capability. Using the NASA/DARPA Horizontal Launch Study (HLS) Point Design 2 (PD-2) as a pointof- departure configuration, two independent design actions were undertaken. Both designs utilized a Boeing 747-400F as the carrier aircraft, LOX/RP-1 first stage and LOX/LH2 second stage. Each design was sized to meet dimensional and mass constraints while optimizing propellant loads and stage delta V splits. All concepts, when fully loaded, exceeded the allowable Gross Takeoff Weight (GTOW) of the aircraft platform. This excess mass was evaluated as propellant/fuel offload available for a potential in-flight propellant loading scenario. Results indicate many advantages such as payload delivery of approximately 47,000 lbm and significant mission flexibility including variable launch site inclination and launch window. However, in-flight cryogenic fluid transfer and carrier aircraft platform integration are substantial technical hurdles to the realization of such a system configuration.

  11. Air Launch: Examining Performance Potential of Various Configurations and Growth Options

    NASA Technical Reports Server (NTRS)

    Waters, Eric D.; Creech, Dennis M.; Philips, Alan

    2013-01-01

    The Advanced Concepts Office at NASA's George C. Marshall Space Flight Center conducted a high-level analysis of various air launch vehicle configurations, objectively determining maximum launch vehicle payload while considering carrier aircraft capabilities and given dimensional constraints. With the renewed interest in aerial launch of low-earth orbit payloads, referenced by programs such as Stratolaunch and Spaceship2, there existed a need to qualify the boundaries of the trade space, identify performance envelopes, and understand advantages and limiting factors of designing for maximum payload capability. Using the NASA/DARPA Horizontal Launch Study (HLS) Point Design 2 (PD-2) as a point-of-departure configuration, two independent design actions were undertaken. Both configurations utilized a Boeing 747-400F as the carrier aircraft, LOX/RP-1 first stage and LOX/LH2 second stage. Each design was sized to meet dimensional and mass constraints while optimizing propellant loads and stage delta V (?V) splits. All concepts, when fully loaded, exceeded the allowable Gross Takeoff Weight (GTOW) of the aircraft platform. This excess mass was evaluated as propellant/fuel offload available for a potential in-flight refueling scenario. Results indicate many advantages such as large, relative payload delivery of approximately 47,000 lbm and significant mission flexibility, such as variable launch site inclination and launch window; however, in-flight cryogenic fluid transfer and carrier aircraft platform integration are substantial technical hurdles to the realization of such a system configuration.

  12. Regionalized PM2.5 Community Multiscale Air Quality model performance evaluation across a continuous spatiotemporal domain

    NASA Astrophysics Data System (ADS)

    Reyes, Jeanette M.; Xu, Yadong; Vizuete, William; Serre, Marc L.

    2017-01-01

    The regulatory Community Multiscale Air Quality (CMAQ) model is a means to understanding the sources, concentrations and regulatory attainment of air pollutants within a model's domain. Substantial resources are allocated to the evaluation of model performance. The Regionalized Air quality Model Performance (RAMP) method introduced here explores novel ways of visualizing and evaluating CMAQ model performance and errors for daily Particulate Matter ≤ 2.5 μm (PM2.5) concentrations across the continental United States. The RAMP method performs a non-homogenous, non-linear, non-homoscedastic model performance evaluation at each CMAQ grid. This work demonstrates that CMAQ model performance, for a well-documented 2001 regulatory episode, is non-homogeneous across space/time. The RAMP correction of systematic errors outperforms other model evaluation methods as demonstrated by a 22.1% reduction in Mean Square Error compared to a constant domain wide correction. The RAMP method is able to accurately reproduce simulated performance with a correlation of r = 76.1%. Most of the error coming from CMAQ is random error with only a minority of error being systematic. Areas of high systematic error are collocated with areas of high random error, implying both error types originate from similar sources. Therefore, addressing underlying causes of systematic error will have the added benefit of also addressing underlying causes of random error.

  13. A passive microfluidic hydrogen-air fuel cell with exceptional stability and high performance.

    PubMed

    Mitrovski, Svetlana M; Nuzzo, Ralph G

    2006-03-01

    We describe an advanced microfluidic hydrogen-air fuel cell (FC) that exhibits exceptional durability and high performance, most notably yielding stable output power (>100 days) without the use of an anode-cathode separator membrane. This FC embraces an entirely passive device architecture and, unlike conventional microfluidic designs that exploit laminar hydrodynamics, no external pumps are used to sustain or localize the reagent flow fields. The devices incorporate high surface area/porous metal and metal alloy electrodes that are embedded and fully immersed in liquid electrolyte confined in the channels of a poly(dimethylsiloxane) (PDMS)-based microfluidic network. The polymeric network also serves as a self-supporting membrane through which oxygen and hydrogen are supplied to the cathode and alloy anode, respectively, by permeation. The operational stability of the device and its performance is strongly dependent on the nature of the electrolyte used (5 M H2SO4 or 2.5 M NaOH) and composition of the anode material. The latter choice is optimized to decrease the sensitivity of the system to oxygen cross-over while still maintaining high activity towards the hydrogen oxidation reaction (HOR). Three types of high surface area anodes were tested in this work. These include: high-surface area electrodeposited Pt (Pt); high-surface area electrodeposited Pd (Pd); and thin palladium adlayers supported on a "porous" Pt electrode (Pd/Pt). The FCs display their best performance in 5 M H2SO4 using the Pd/Pt anode. This exceptional stability and performance was ascribed to several factors, namely: the high permeabilities of O2, H2, and CO2 in PDMS; the inhibition of the formation of insoluble carbonate species due to the presence of a highly acidic electrolyte; and the selectivity of the Pd/Pt anode toward the HOR. The stability of the device for long-term operation was modeled using a stack of three FCs as a power supply for a portable display that otherwise uses a 3 V

  14. Nuclear Air-Brayton Combined Cycle Power Conversion Design, Physical Performance Estimation and Economic Assessment

    NASA Astrophysics Data System (ADS)

    Andreades, Charalampos

    The combination of an increased demand for electricity for economic development in parallel with the widespread push for adoption of renewable energy sources and the trend toward liberalized markets has placed a tremendous amount of stress on generators, system operators, and consumers. Non-guaranteed cost recovery, intermittent capacity, and highly volatile market prices are all part of new electricity grids. In order to try and remediate some of these effects, this dissertation proposes and studies the design and performance, both physical and economic, of a novel power conversion system, the Nuclear Air-Brayton Combined Cycle (NACC). The NACC is a power conversion system that takes a conventional industrial frame type gas turbine, modifies it to accept external nuclear heat at 670°C, while also maintaining its ability to co-fire with natural gas to increase temperature and power output at a very quick ramp rate. The NACC addresses the above issues by allowing the generator to gain extra revenue through the provision of ancillary services in addition to energy payments, the grid operator to have a highly flexible source of capacity to back up intermittent renewable energy sources, and the consumer to possibly see less volatile electricity prices and a reduced probability of black/brown outs. This dissertation is split into six sections that delve into specific design and economic issues related to the NACC. The first section describes the basic design and modifications necessary to create a functional externally heated gas turbine, sets a baseline design based upon the GE 7FB, and estimates its physical performance under nominal conditions. The second section explores the off-nominal performance of the NACC and characterizes its startup and shutdown sequences, along with some of its safety measures. The third section deals with the power ramp rate estimation of the NACC, a key performance parameter in a renewable-heavy grid that needs flexible capacity. The

  15. Dynamic Radioactive Source for Evaluating and Demonstrating Time-dependent Performance of Continuous Air Monitors.

    PubMed

    McLean, Thomas D; Moore, Murray E; Justus, Alan L; Hudston, Jonathan A; Barbé, Benoît

    2016-11-01

    Evaluation of continuous air monitors in the presence of a plutonium aerosol is time intensive, expensive, and requires a specialized facility. The Radiation Protection Services Group at Los Alamos National Laboratory has designed a Dynamic Radioactive Source, intended to replace plutonium aerosol challenge testing. The Dynamic Radioactive Source is small enough to be inserted into the sampler filter chamber of a typical continuous air monitor. Time-dependent radioactivity is introduced from electroplated sources for real-time testing of a continuous air monitor where a mechanical wristwatch motor rotates a mask above an alpha-emitting electroplated disk source. The mask is attached to the watch's minute hand, and as it rotates, more of the underlying source is revealed. The measured alpha activity increases with time, simulating the arrival of airborne radioactive particulates at the air sampler inlet. The Dynamic Radioactive Source allows the temporal behavior of puff and chronic release conditions to be mimicked without the need for radioactive aerosols. The new system is configurable to different continuous air monitor designs and provides an in-house testing capability (benchtop compatible). It is a repeatable and reusable system and does not contaminate the tested air monitor. Test benefits include direct user control, realistic (plutonium) aerosol spectra, and iterative development of continuous air monitor alarm algorithms. Data obtained using the Dynamic Radioactive Source has been used to elucidate alarm algorithms and to compare the response time of two commercial continuous air monitors.

  16. Performance Evaluation of a Low-Cost, Real-Time Community Air Monitoring Station

    EPA Science Inventory

    The US EPA’s Village Green Project (VGP) is an example of using innovative technology to enable community-level low-cost real-time air pollution measurements. The VGP is an air monitoring system configured as a park bench located outside of a public library in Durham, NC. It co...

  17. Dynamic Radioactive Source for Evaluating and Demonstrating Time-dependent Performance of Continuous Air Monitors

    SciTech Connect

    McLean, Thomas D.; Moore, Murray E.; Justus, Alan L.; Hudston, Jonathan A.; Barbé, Benoît

    2016-01-01

    Evaluation of continuous air monitors in the presence of a plutonium aerosol is time intensive, expensive, and requires a specialized facility. The Radiation Protection Services Group at Los Alamos National Laboratory has designed a Dynamic Radioactive Source, intended to replace plutonium aerosol challenge testing. Furthermore, the Dynamic Radioactive Source is small enough to be inserted into the sampler filter chamber of a typical continuous air monitor. Time-dependent radioactivity is introduced from electroplated sources for real-time testing of a continuous air monitor where a mechanical wristwatch motor rotates a mask above an alpha-emitting electroplated disk source. The mask is attached to the watch’s minute hand, and as it rotates, more of the underlying source is revealed. The alpha activity we measured increases with time, simulating the arrival of airborne radioactive particulates at the air sampler inlet. The Dynamic Radioactive Source allows the temporal behavior of puff and chronic release conditions to be mimicked without the need for radioactive aerosols. The new system is configurable to different continuous air monitor designs and provides an in-house testing capability (benchtop compatible). It is a repeatable and reusable system and does not contaminate the tested air monitor. Test benefits include direct user control, realistic (plutonium) aerosol spectra, and iterative development of continuous air monitor alarm algorithms. We also used data obtained using the Dynamic Radioactive Source to elucidate alarm algorithms and to compare the response time of two commercial continuous air monitors.

  18. Dynamic Radioactive Source for Evaluating and Demonstrating Time-dependent Performance of Continuous Air Monitors

    DOE PAGES

    McLean, Thomas D.; Moore, Murray E.; Justus, Alan L.; ...

    2016-01-01

    Evaluation of continuous air monitors in the presence of a plutonium aerosol is time intensive, expensive, and requires a specialized facility. The Radiation Protection Services Group at Los Alamos National Laboratory has designed a Dynamic Radioactive Source, intended to replace plutonium aerosol challenge testing. Furthermore, the Dynamic Radioactive Source is small enough to be inserted into the sampler filter chamber of a typical continuous air monitor. Time-dependent radioactivity is introduced from electroplated sources for real-time testing of a continuous air monitor where a mechanical wristwatch motor rotates a mask above an alpha-emitting electroplated disk source. The mask is attached tomore » the watch’s minute hand, and as it rotates, more of the underlying source is revealed. The alpha activity we measured increases with time, simulating the arrival of airborne radioactive particulates at the air sampler inlet. The Dynamic Radioactive Source allows the temporal behavior of puff and chronic release conditions to be mimicked without the need for radioactive aerosols. The new system is configurable to different continuous air monitor designs and provides an in-house testing capability (benchtop compatible). It is a repeatable and reusable system and does not contaminate the tested air monitor. Test benefits include direct user control, realistic (plutonium) aerosol spectra, and iterative development of continuous air monitor alarm algorithms. We also used data obtained using the Dynamic Radioactive Source to elucidate alarm algorithms and to compare the response time of two commercial continuous air monitors.« less

  19. Performance Assessment of Hazardous Air Pollutant (HAP)Free Chemical Paint Strippers on Military Coatings for Validation to Federal Specification TT-R-2918A

    DTIC Science & Technology

    2016-03-01

    ARL-TN-0742 ● MAR 2016 US Army Research Laboratory Performance Assessment of Hazardous Air Pollutant (HAP)–Free Chemical Paint...the originator. ARL-TN-0742 ● MAR 2016 US Army Research Laboratory Performance Assessment of Hazardous Air Pollutant (HAP...COVERED (From - To) 1–30 April 2014 4. TITLE AND SUBTITLE Performance Assessment of Hazardous Air Pollutant (HAP)–Free Chemical Paint Strippers

  20. Effect of air deflectors on fan performance in tunnel-ventilated broiler houses with a dropped ceiling

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Air velocity is a critical design parameter for modern commercial broiler houses, owing to the beneficial effects of increased cooling on live performance and thermal comfort in broiler chickens. As a result, design velocities have increased over the last 15 years and broiler growers have installed ...

  1. The Science and Art of Grand Rond de Jambe en l'air: Applications to Teaching and Performance

    ERIC Educational Resources Information Center

    Wilson, Margaret

    2008-01-01

    Recommendations for the teaching and performance of grand rond de jambe en l'air are presented. Incorporating both quantitative and qualitative data, information generated from biomechanic analysis is balanced with observation of the testing and questionnaire and interview data. The voices of the participants in the research contribute to an…

  2. 42 CFR 84.1143 - Dust, fume, and mist air-purifying filter tests; performance requirements; general.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Dust, fume, and mist air-purifying filter tests; performance requirements; general. 84.1143 Section 84.1143 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL...

  3. 42 CFR 84.159 - Man tests for gases and vapors; supplied-air respirators; general performance requirements.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Man tests for gases and vapors; supplied-air respirators; general performance requirements. 84.159 Section 84.159 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE...

  4. 42 CFR 84.159 - Man tests for gases and vapors; supplied-air respirators; general performance requirements.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Man tests for gases and vapors; supplied-air respirators; general performance requirements. 84.159 Section 84.159 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE...

  5. 42 CFR 84.159 - Man tests for gases and vapors; supplied-air respirators; general performance requirements.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Man tests for gases and vapors; supplied-air respirators; general performance requirements. 84.159 Section 84.159 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE...

  6. 42 CFR 84.159 - Man tests for gases and vapors; supplied-air respirators; general performance requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Man tests for gases and vapors; supplied-air respirators; general performance requirements. 84.159 Section 84.159 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE...

  7. 42 CFR 84.159 - Man tests for gases and vapors; supplied-air respirators; general performance requirements.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Man tests for gases and vapors; supplied-air respirators; general performance requirements. 84.159 Section 84.159 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE...

  8. Preliminary analysis of problem of determining experimental performance of air-cooled turbine III : methods for determining power and efficiency

    NASA Technical Reports Server (NTRS)

    Ellerbrock, Herman H , Jr; Ziemer, Robert R

    1950-01-01

    Suggested formula are given for determining air-cooled turbine-performance characteristics, such as power and efficiency, as functions of certain parameters. These functions, generally being unknown, are determined from experimental data obtained from specific investigations. Special plotting methods for isolating the effect of each parameter are outlined.

  9. Performance Summary of the 2006 Community Multiscale Air Quality (CMAQ) Simulation for the AQMEII Project: North American Application

    EPA Science Inventory

    The CMAQ modeling system has been used to simulate the CONUS using 12-km by 12-km horizontal grid spacing for the entire year of 2006 as part of the Air Quality Model Evaluation International initiative (AQMEII). The operational model performance for O3 and PM2.5<...

  10. North and west sides of the cooling tower, utility building ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    North and west sides of the cooling tower, utility building (building 2606) is in the background at right - March Air Force Base, Strategic Air Command, Cooling Tower, 5220 Riverside Drive, Moreno Valley, Riverside County, CA

  11. 2. SOUTHEAST SIDE. HIGH PRESSURE HELIUM STORAGE TANKS AT LEFT. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. SOUTHEAST SIDE. HIGH PRESSURE HELIUM STORAGE TANKS AT LEFT. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Helium Compression Plant, Test Area 1-115, intersection of Altair & Saturn Boulevards, Boron, Kern County, CA

  12. NORTH REAR AND WEST SIDE, Looking southeast down Saturn Boulevard. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    NORTH REAR AND WEST SIDE, Looking southeast down Saturn Boulevard. February, 1998 - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Electrical Substation, Test Area 1-115, northwest end of Saturn Boulevard, Boron, Kern County, CA

  13. 6. DETAIL, WEST SIDE, SOUTH BAY, SHOWING ENTRANCE TO INSTRUMENTATION ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. DETAIL, WEST SIDE, SOUTH BAY, SHOWING ENTRANCE TO INSTRUMENTATION ROOM. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Test Stand 1-4, Test Area 1-115, northwest end of Saturn Boulevard, Boron, Kern County, CA

  14. 6. BUILDING 8768, NORTHWEST SIDE AND SOUTHWEST FRONT. Edwards ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. BUILDING 8768, NORTHWEST SIDE AND SOUTHWEST FRONT. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Observation Bunkers for Test Stand 1-A, Test Area 1-120, north end of Jupiter Boulevard, Boron, Kern County, CA

  15. 8. BUILDING 8769, WEST FRONT AND SOUTH SIDE. Edwards ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. BUILDING 8769, WEST FRONT AND SOUTH SIDE. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Observation Bunkers for Test Stand 1-A, Test Area 1-120, north end of Jupiter Boulevard, Boron, Kern County, CA

  16. 2. BUILDING 8767, SOUTH FRONT AND EAST SIDE. Edwards ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. BUILDING 8767, SOUTH FRONT AND EAST SIDE. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Observation Bunkers for Test Stand 1-A, Test Area 1-120, north end of Jupiter Boulevard, Boron, Kern County, CA

  17. 1. NORTHWEST SIDE AND SOUTHWEST FRONT. Looking east. Edwards ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. NORTHWEST SIDE AND SOUTHWEST FRONT. Looking east. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Firing Control Building, Test Area 1-100, northeast end of Test Area 1-100 Road, Boron, Kern County, CA

  18. NORTH SIDES OF LIQUID OXYGEN TANKS. Looking southwest along railroad ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    NORTH SIDES OF LIQUID OXYGEN TANKS. Looking southwest along railroad track to AF Plant 72 - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Liquid Oxygen & Nitrogen Storage Tank Farm, Intersection of Altair & Jupiter Boulevards, Boron, Kern County, CA

  19. SOUTH SIDE OF TANKS. LOADING DOCK, WITH FIRST AID STATION ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    SOUTH SIDE OF TANKS. LOADING DOCK, WITH FIRST AID STATION IN LEFT FOREGROUND - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Liquid Oxygen & Nitrogen Storage Tank Farm, Intersection of Altair & Jupiter Boulevards, Boron, Kern County, CA

  20. 5. EAST SIDE, TEST STAND AND ITS SUPERSTRUCTURE. Edwards ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. EAST SIDE, TEST STAND AND ITS SUPERSTRUCTURE. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Test Stand 1-A, Test Area 1-120, north end of Jupiter Boulevard, Boron, Kern County, CA

  1. 13. OBSERVATION HALL ALONG WEST SIDE. DOUBLE DOORS LEAD TO ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    13. OBSERVATION HALL ALONG WEST SIDE. DOUBLE DOORS LEAD TO MAIN ROOM. Looking north. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Instrumentation & Control Building, Test Area 1-115, northwest end of Saturn Boulevard, Boron, Kern County, CA

  2. Performance analysis of liquid air energy storage utilizing LNG cold energy

    NASA Astrophysics Data System (ADS)

    Luyao, Li; Sixian, Wang; Zhang, Deng; Luwei, Yang; Yuan, Zhou; Junjie, Wang

    2017-02-01

    As the high energy density and can be stored in a long period, the liquid air is regarded as the potential energy storage medium. In the liquid air energy storage (LAES) system, liquid air is produced in the liquefaction processes by using the renewable energy or off-peak energy. The compressor is used to supply and recycle the air in liquefaction processes. In this paper, a LAES model is established, and the impact of compressor on LAES system is analysed theoretically. Liquid air energy storage (LAES) system utilizing LNG cold energy is also described. The results show that the round trip energy efficiency is enhanced and the utilizing has promising application prospect for large scale energy storage.

  3. [Studies on the performance of the dental air turbine handpieces. (Part 5) Rotational performance of various kinds of dental air turbine handpieces (N = N0--CvFv gamma) (author's transl)].

    PubMed

    Miyairi, H; Nagai, M; Fukuda, H; Muramatsu, A

    1981-10-01

    Making research on the rotational performance of the dental air turbine handpieces widely used for dental cutting instruments, we investigated with the relation between rotational speed and load on many kinds of dental handpieces used for clinical divisions and with the applications of the theoretical equations to have be shown in the previous report. And then we have the investigation on these properties. Dental handpieces to measured with these properties were classified the four types, standard types, torque type, miniature type and air bearing type. And we applied the experimental equations to these experimental values and determined the rotational coefficients, gamma and Cv. The rotational speed N and normal force Fv, which occurred the maximum work of air turbine handpieces, were calculated with our analysis and then these values of N and Fv were compared with the experimental results. These results, that is, experimental and calculated values have a good agreement and the development of the theoretical approach is useful for the estimation of the rotational performance. And we examined the possibility of rotational performance's estimation with the process of simple experiment on these air turbine handpieces.

  4. Modeling of coupled thermodynamic and geomechanical performance of underground compressed air energy storage in lined rock caverns

    SciTech Connect

    Rutqvist, Jonny; Kim, Hyung-Mok; Ryu, Dong-Woo; Synn, Joong-Ho; Song, Won-Kyong

    2012-06-01

    We applied coupled nonisothermal, multiphase fluid flow and geomechanical numerical modeling to study the coupled thermodynamic and geomechanical performance of underground compressed air energy storage (CAES) in concrete-lined rock caverns. The paper focuses on CAES in lined caverns at relatively shallow depth (e.g., 100 m depth) in which a typical CAES operational pressure of 5 to 8 MPa is significantly higher than both ambient fluid pressure and in situ stress. We simulated a storage operation that included cyclic compression and decompression of air in the cavern, and investigated how pressure, temperature and stress evolve over several months of operation. We analyzed two different lining options, both with a 50 cm thick low permeability concrete lining, but in one case with an internal synthetic seal such as steel or rubber. For our simulated CAES system, the thermodynamic analysis showed that 96.7% of the energy injected during compression could be recovered during subsequent decompression, while 3.3% of the energy was lost by heat conduction to the surrounding media. Our geomechanical analysis showed that tensile effective stresses as high as 8 MPa could develop in the lining as a result of the air pressure exerted on the inner surface of the lining, whereas thermal stresses were relatively smaller and compressive. With the option of an internal synthetic seal, the maximum effective tensile stress was reduced from 8 to 5 MPa, but was still in substantial tension. We performed one simulation in which the tensile tangential stresses resulted in radial cracks and air leakage though the lining. This air leakage, however, was minor (about 0.16% of the air mass loss from one daily compression) in terms of CAES operational efficiency, and did not significantly impact the overall energy balance of the system. However, despite being minor in terms of energy balance, the air leakage resulted in a distinct pressure increase in the surrounding rock that could be

  5. Sparkover performance and gap factors of air gaps below 1 meter: Analysis of published data. Final report

    SciTech Connect

    Gela, G.

    1998-03-01

    This report is an account of a literature search on sparkover performance of various air gaps shorter than 1 meter. The report is a part of the Live Working 2000 project. The objective of the literature search was to locate and analyze published data on sparkover performance of air gaps below 1 meter, with special emphasis on live working. Published data dating back to 1930`s are analyzed for a variety of air gaps: rod-to-plane; rod-to-rod; sphere-to-plane; bundle-to-plane; hoop-to-plane, conductor-to-rod; and worker-to-tower. Data for all voltage types, and both polarities (where applicable) are analyzed: power frequency alternating current; direct current; lightning; fast front impulse; and switching impulse. As is the case for longer air gaps and higher voltages, several accurate empirical formulae for calculation of the sparkover voltage have been developed, and are analyzed. Also, the rod-to-plane air gap is used in this report as the reference gap for calculation of gap factors.

  6. Side Effects of Physical Training: Association of Fitness Improvement to Espirt de Corps, Performance, Health, and Attrition in Marine Corps Basic Training. Report No. 83-37.

    ERIC Educational Resources Information Center

    Vickers, R. R., Jr.

    Physical training is a significant element of Marine Corps basic training which may affect nonfitness basic training outcomes in addition to improving fitness. If so, physical training side effects should be considered when designing and evaluating physical training programs. This study capitalized on naturally occurring platoon differences in…

  7. The Performance of a Desiccant-Based air Conditioner on a Florida School

    SciTech Connect

    Miller, J.

    2001-08-22

    Indoor air quality has become a major public health issue in recent years. ASHRAE standard 62-1989-which is an attempt to improve indoor air quality by increasing building ventilation rates-greatly increases the latent loads on many buildings. In more humid climates, the Sensible Heat Ratio (SHR) of a building's air conditioner (which is the fraction of total delivered cooling that is sensible) is too high to meet the existing latent loads. The implementation of ASHRAE 62-1989 will only exacerbate this problem.

  8. Thermal Comfort Study of a Compact Thermoelectric Air Conditioner

    NASA Astrophysics Data System (ADS)

    Maneewan, S.; Tipsaenprom, W.; Lertsatitthanakorn, C.

    2010-09-01

    This paper evaluates the cooling performance and thermal comfort of a compact thermoelectric (TE) air conditioner. The compact TE air conditioner is composed of three TE modules. The cold and hot sides of the TE modules were fixed to rectangular fin heat sinks and fans. Thermal acceptability assessment was performed to find out whether the cooled air met the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) Standard-55’s 80% acceptability criteria. A suitable condition occurred at 1 A current flow with a corresponding cooling capacity of 29.2 W, giving an average cooled air temperature of 28°C and 0.9 m/s cooled air velocity. The coefficient of performance was calculated and found to be ˜0.34. Economic analysis indicates that the payback period is 0.75 years when one compact TE air conditioner unit is used instead of a 1-ton conventional air conditioner.

  9. 75 FR 19310 - Delegation of New Source Performance Standards and National Emission Standards for Hazardous Air...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-14

    ... INFORMATION CONTACT: Mr. Kenneth Boyce, Air Planning Section (6PD-L), Environmental Protection Agency, Region...-7263, e-mail address boyce.kenneth@epa.gov . SUPPLEMENTARY INFORMATION: In the final rules section...

  10. Performance Evaluation of a Lower-Cost, Real-Time Community Air Monitoring Station

    EPA Science Inventory

    These slides describe the Village Green Project prototype and how the measurements compare wtih nearby FEMs, including the OAQPS data collected at the AIRS site on the EPA-RTP campus and the NCDENR FEMs in the Triangle area.

  11. A PERFORMANCE EVALUATION OF THE ETA- CMAQ AIR QUALITY FORECAST SYSTEM FOR THE SUMMER OF 2005

    EPA Science Inventory

    This poster presents an evaluation of the Eta-CMAQ Air Quality Forecast System's experimental domain using O3 observations obtained from EPA's AIRNOW program and a suite of statistical metrics examining both discrete and categorical forecasts.

  12. Preliminary investigation of cooling-air ejector performance at pressure ratios from 1 to 10

    NASA Technical Reports Server (NTRS)

    Ellis, C W; Hollister, D P; Sargent, A F , Jr

    1951-01-01

    Preliminary investigation was made of conical cooling air ejector at primary pressure ratios from 1 to 10. The cooling-air flow was maintained at zero and the resulting pressure variation in the shroud indicated pumping ability. The cooling-air flow was maintained at zero and the resulting pressure variation in the shroud indicated pumping ability. The gross thrust of the ejector and nozzle were compared. Several ratios of the spacing between the nozzle and shroud exit to the nozzle exit diameter were investigated for several shroud to nozzle exit diameter ratios. Maximum gross thrust loss occurred under conditions of zero cooling-air flow and was as much as 35 percent below nozzle jet thrust. For minimum thrust loss, ejector should be designed with as low diameter and spacing ratio as possible.

  13. Benchmark performance analysis of an ECM-modulated air-to-air heat pump with a reciprocating compressor

    SciTech Connect

    Rice, C.K.

    1992-01-01

    A benchmark analysis was conducted to predict the maximum steady- state performance potential of a near-term modulating residential- size heat pump. Continuously variable-speed, permanent-magnet electronically commutated motors (ECMs) were assumed to modulate the compressor and the indoor and outdoor fans in conjunction with existing modulating reciprocating compressor technology. A modulating heat pump design tool was used to optimize this ECM benchmark heat pump, using speed ranges and total heat exchanger sizes per-unit-capacity equivalent to that used by the highest SEER-rated variable-speed unit presently on the market (SEER = 16.4). Parametric steady-state performance optimization was conducted at a nominal design cooling ambient of 95{degree}F (35{degree}C) and at three off-design ambients of 82{degree}F (27.8{degree}C) cooling and 47{degree}F and 17{degree}F (8.3{degree}C and {minus}8.3{degree}C) heating. In comparison to the reference commercially available residential unit, the analysis for the ECM benchmark predicted steady-state heating COPs about 35% higher and a cooling EER almost 25% higher at the nominal design cooling condition. The cooling EER at 82{degree}F (27. 8{degree}C) was 13% higher than that of the reference unit when a comparable sensible heat ratio of 0.71 was maintained, while an EER gain of 24% at the 82{degree}F (27.8{degree}C) rating point was predicted when the sensible heat ratio was relaxed to 0.83. 28 refs., 14 figs., 7 tabs.

  14. Performance Expectations for Future Moderate Resolution Visible and Infrared Space Instruments Based on AIRS and MODIS In-Flight Experience

    NASA Technical Reports Server (NTRS)

    Pagano, Thomas S.; Broberg, Steven E.; Aumann, Hartmut H.; Baron, Richard L.

    2004-01-01

    Lessons learned from the Atmospheric Infrared Sounder (AIRS) and the Moderate Resolution Imaging Spectroradiometer (MODIS) projects highlight areas where further technology development is needed to address future land, ocean and atmospheric measurement needs. Although not established as requirements at this time, it is anticipated that scientists will expect improvements in the areas of spatial, spectral, radiometric, polarimetric, temporal and calibration performance for future sensors. This paper addresses each of these performance areas and provides lessons learned from MODIS and AIRS. We also present expectations in performance of the system based on information from NASA Instrument Incubator Program and industry reports. Tradeoffs are presented vs orbit altitude (LEO, ME0 and GEO) and provide a 'systems' perspective to future measurement concepts.

  15. Canandaigua Wines: Compressed Air System Upgrade Saves Energy and Improves Performance at a Winery

    SciTech Connect

    2005-03-01

    In June 2004, Canandaigua Wine Company (CWC) completed an upgrade project on the compressed air system at its winery in Lodi, California. Before the project, the winery depended on two compressors to satisfy its production requirements. Anticipating an expansion of its production capacity, the winery commissioned a review of the compressed air system by a U.S. Department of Energy (DOE) Qualifi ed AIRMaster+ Specialist at Atlas Copco Compressors, Inc.

  16. Improved performance of air-cathode single-chamber microbial fuel cell for wastewater treatment using microfiltration membranes and multiple sludge inoculation

    NASA Astrophysics Data System (ADS)

    Sun, Jian; Hu, Yongyou; Bi, Zhe; Cao, Yunqing

    Substantial optimization and cost reduction are required before microbial fuel cells (MFCs) can be practically applied. We show here the performance improvement of an air-cathode single-chamber MFC by using a microfiltration membrane (MFM) on the water-facing side of the cathode and using multiple aerobic sludge (AES), anaerobic sludge (ANS), and wetland sediment (WLS) as anodic inoculums. Batch test results show that the MFC with an MFM resulted in an approximately two-fold increase in maximum power density compared to the MFC with a proton exchange membrane (PEM). The Coulombic efficiency increased from 4.17% to 5.16% in comparison with the membrane-less MFC, without a significant negative effect on power generation and internal resistance. Overall performance of the MFC was also improved by using multiple sludge inoculums in the anode. The MFC inoculated with ANS + WLS produced the greatest maximal power density of 373 mW m -2 with a substantially low internal resistance of 38 Ω. Higher power density with a decreased internal resistance was also achieved in MFC inoculated with ANS + AES and ANS + AES + WLS in comparison with those inoculated with only one sludge. The MFCs inoculated with AES + ANS achieved the highest Coulombic efficiency. Over 92% COD was removed from confectionery wastewater in all tested MFCs, regardless of the membrane or inoculum used.

  17. Evaluating the Environmental Performance of the U.S. Next Generation Air Transportation System

    NASA Technical Reports Server (NTRS)

    Graham, Michael; Augustine, Stephen; Ermatinger, Christopher; Difelici, John; Thompson, Terence R.; Marcolini, Michael A.; Creedon, Jeremiah F.

    2009-01-01

    The environmental impacts of several possible U.S. Next Generation Air Transportation scenarios have been quantitatively evaluated for noise, air-quality, fuel-efficiency, and CO2 impacts. Three principal findings have emerged. (1) 2025 traffic levels about 30% higher than 2006 are obtained by increasing traffic according to FAA projections while also limiting traffic at each airport using reasonable ratios of demand to capacity. NextGen operational capabilities alone enable attainment of an additional 10-15% more flights beyond that 2025 baseline level with negligible additional noise, air-quality, and fuel-efficiency impacts. (2) The addition of advanced engine and airframe technologies provides substantial additional reductions in noise and air-quality impacts, and further improves fuel efficiency. 2025 environmental goals based on projected system-wide improvement rates of about 1% per year for noise and fuel-efficiency (an air-quality goal is not yet formulated) are achieved using this new vehicle technology. (3) Overall air-transport "product", as measured by total flown distance or total payload distance, increases by about 50% relative to 2006, but total fuel consumption and CO2 production increase by only about 40% using NextGen operational capabilities. With the addition of advanced engine/airframe technologies, the increase in total fuel consumption and CO2 production can be reduced to about 30%.

  18. Influence of number of dental autoclave treatment cycles on rotational performance of commercially available air-turbine handpieces.

    PubMed

    Nagai, Masahiro; Takakuda, Kazuo

    2006-06-01

    The influence of number of autoclave treatment cycles (N) on rotational speed and total indicated run-out of commercially available air-turbine handpieces from five manufacturers was investigated at N=0, 50, 100, 150, 200, 250 and 300 cycles, and the significance in the test results was assessed by Dunnett's multiple comparison test. Some air-turbine handpieces showed the significant differences in rotational speed at N=300 cycles, however, the decreases of the rotational speeds were only 1 to 3.5 percent. Some air-turbine handpieces showed the significant differences in total indicated run-out, however, the respective values were smaller than that at N=0 cycle. Accordingly, it can be considered that the ball bearing in the air-turbine handpieces is not affected significantly by autoclave. To further evaluate rotational performance, this study focused on the rotational vibration of the ball bearing components of the air-turbine, as measured by Fast Fourier Transform (FFT) analysis; the power spectra of frequency of the ball's revolution, frequency of the cage's rotation and frequency of the ball's rotation were comparatively investigated at N=0, 150 and 300 cycles, and the influence of autoclave was evaluated qualitatively. No abnormalities in the ball bearings were recognized.

  19. Side-Chain Fluorination: An Effective Approach to Achieving High-Performance All-Polymer Solar Cells with Efficiency Exceeding 7.

    PubMed

    Oh, Jiho; Kranthiraja, Kakaraparthi; Lee, Changyeon; Gunasekar, Kumarasamy; Kim, Seonha; Ma, Biwu; Kim, Bumjoon J; Jin, Sung-Ho

    2016-12-01

    Side-chain fluorination of polymers is demonstrated as a highly effective strategy to improve the efficiency of all-polymer solar cells from 2.93% (nonfluorinated P1) to 7.13% (fluorinated P2). This significant enhancement is achieved by synergistic improvements in open-circuit voltage, charge generation, and charge transport, as fluorination of the donor polymer optimizes the band alignment and the film morphology.

  20. A piloted simulation of helicopter air combat to investigate effects of variations in selected performance and control response characteristics

    NASA Technical Reports Server (NTRS)

    Lewis, Michael S.; Mansur, M. Hossein; Chen, Robert T. N.

    1987-01-01

    A piloted simulation study investigating handling qualities and flight characteristics required for helicopter air to air combat is presented. The Helicopter Air Combat system was used to investigate this role for Army rotorcraft. Experimental variables were the maneuver envelope size (load factor and sideslip), directional axis handling qualities, and pitch and roll control-response type. Over 450 simulated, low altitude, one-on-one engagements were conducted. Results from the experiment indicate that a well damped directional response, low sideforce caused by sideslip, and some effective dihedral are all desirable for weapon system performance, good handling qualities, and low pilot workload. An angular rate command system was favored over the attitude type pitch and roll response for most applications, and an enhanced maneuver envelope size over that of current generation aircraft was found to be advantageous. Pilot technique, background, and experience are additional factors which had a significant effect on performance in the air combat tasks investigated. The implication of these results on design requirements for future helicopters is presented.

  1. Performance factors as a basis of practical fault detection and diagnostic methods for air-handling units

    SciTech Connect

    Kaerki, S.H.; Karjalainen, S.J.

    1999-07-01

    The technical term performance is defined as how well a system fulfills its intended purpose in different operational circumstances. This paper describes the process of establishing the performance factors of air-handling units (AHUs), defining the performance requirements, and connecting them to fault detection and diagnosis methods. The most important performance requirements of AHUs are related to heating and cooling energy, the supply airflow rate and purity, energy efficiency, and control quality. Many solutions made during different life-cycle phases affect the final system performance. These solutions are discussed in this paper. Diagnostic tools and methods can be developed for monitoring the defined performance criteria. Practical FDD methods have been developed for the system considered here. The methods are simple and easy to apply in practice. Methods for monitoring the heat recovery unit and the AHU energy use are presented. Examples of utilizing characteristic curves and fault-symptom trees are also described.

  2. Low-Flow Liquid Desiccant Air-Conditioning: Demonstrated Performance and Cost Implications

    SciTech Connect

    Kozubal, E.; Herrmann, L.; Deru, M.; Clark, J.; Lowenstein, A.

    2014-09-01

    Cooling loads must be dramatically reduced when designing net-zero energy buildings or other highly efficient facilities. Advances in this area have focused primarily on reducing a building's sensible cooling loads by improving the envelope, integrating properly sized daylighting systems, adding exterior solar shading devices, and reducing internal heat gains. As sensible loads decrease, however, latent loads remain relatively constant, and thus become a greater fraction of the overall cooling requirement in highly efficient building designs, particularly in humid climates. This shift toward latent cooling is a challenge for heating, ventilation, and air-conditioning (HVAC) systems. Traditional systems typically dehumidify by first overcooling air below the dew-point temperature and then reheating it to an appropriate supply temperature, which requires an excessive amount of energy. Another dehumidification strategy incorporates solid desiccant rotors that remove water from air more efficiently; however, these systems are large and increase fan energy consumption due to the increased airside pressure drop of solid desiccant rotors. A third dehumidification strategy involves high flow liquid desiccant systems. These systems require a high maintenance separator to protect the air distribution system from corrosive desiccant droplet carryover and so are more commonly used in industrial applications and rarely in commercial buildings. Both solid desiccant systems and most high-flow liquid desiccant systems (if not internally cooled) add sensible energy which must later be removed to the air stream during dehumidification, through the release of sensible heat during the sorption process.

  3. Emotional Side Effects

    MedlinePlus

    ... En Español Category Treatment & Support Treatments and Side Effects Coping with Cancer In this section you can ... Finding and Paying for Treatment Treatments and Side Effects Survivorship: During and After Treatment Caregivers and Family ...

  4. Side Effects (Management)

    MedlinePlus

    ... Cancer is Treated Side Effects Dating, Sex, and Reproduction Advanced Cancer For Children For Teens For Young ... Cancer is Treated Side Effects Dating, Sex, and Reproduction Advanced Cancer For Children For Teens For Young ...

  5. Neural Markers of Performance States in an Olympic Athlete: An EEG Case Study in Air-Pistol Shooting.

    PubMed

    di Fronso, Selenia; Robazza, Claudio; Filho, Edson; Bortoli, Laura; Comani, Silvia; Bertollo, Maurizio

    2016-06-01

    This study focused on identifying the neural markers underlying optimal and suboptimal performance experiences of an elite air-pistol shooter, based on the tenets of the multi-action plan (MAP) model. According to the MAP model's assumptions, skilled athletes' cortical patterns are expected to differ among optimal/automatic (Type 1), optimal/controlled (Type 2), suboptimal/controlled (Type 3), and suboptimal/automatic (Type 4) performance experiences. We collected performance (target pistol shots), cognitive-affective (perceived control, accuracy, and hedonic tone), and cortical activity data (32-channel EEG) of an elite shooter. Idiosyncratic descriptive analyses revealed differences in perceived accuracy in regard to optimal and suboptimal performance states. Event-Related Desynchronization/Synchronization analysis supported the notion that optimal-automatic performance experiences (Type 1) were characterized by a global synchronization of cortical arousal associated with the shooting task, whereas suboptimal controlled states (Type 3) were underpinned by high cortical activity levels in the attentional brain network. Results are addressed in light of the neural efficiency hypothesis and reinvestment theory. Perceptual training recommendations aimed at restoring optimal performance levels are discussed. Key pointsWe investigated the neural markers underlying optimal and suboptimal performance experiences of an elite air-pistol shooter.Optimal/automatic performance is characterized by a global synchronization of cortical activity associated with the shooting task.Suboptimal controlled performance is characterized by high cortical arousal levels in the attentional brain networks.Focused Event Related Desynchronization activity during Type 1 performance in frontal midline theta was found, with a clear distribution of Event Related Synchronization in the frontal and central areas just prior to shot release.Event Related Desynchronization patterns in low Alpha band

  6. Neural Markers of Performance States in an Olympic Athlete: An EEG Case Study in Air-Pistol Shooting

    PubMed Central

    di Fronso, Selenia; Robazza, Claudio; Filho, Edson; Bortoli, Laura; Comani, Silvia; Bertollo, Maurizio

    2016-01-01

    This study focused on identifying the neural markers underlying optimal and suboptimal performance experiences of an elite air-pistol shooter, based on the tenets of the multi-action plan (MAP) model. According to the MAP model’s assumptions, skilled athletes’ cortical patterns are expected to differ among optimal/automatic (Type 1), optimal/controlled (Type 2), suboptimal/controlled (Type 3), and suboptimal/automatic (Type 4) performance experiences. We collected performance (target pistol shots), cognitive-affective (perceived control, accuracy, and hedonic tone), and cortical activity data (32-channel EEG) of an elite shooter. Idiosyncratic descriptive analyses revealed differences in perceived accuracy in regard to optimal and suboptimal performance states. Event-Related Desynchronization/Synchronization analysis supported the notion that optimal-automatic performance experiences (Type 1) were characterized by a global synchronization of cortical arousal associated with the shooting task, whereas suboptimal controlled states (Type 3) were underpinned by high cortical activity levels in the attentional brain network. Results are addressed in light of the neural efficiency hypothesis and reinvestment theory. Perceptual training recommendations aimed at restoring optimal performance levels are discussed. Key points We investigated the neural markers underlying optimal and suboptimal performance experiences of an elite air-pistol shooter. Optimal/automatic performance is characterized by a global synchronization of cortical activity associated with the shooting task. Suboptimal controlled performance is characterized by high cortical arousal levels in the attentional brain networks. Focused Event Related Desynchronization activity during Type 1 performance in frontal midline theta was found, with a clear distribution of Event Related Synchronization in the frontal and central areas just prior to shot release. Event Related Desynchronization patterns in low

  7. 75 FR 59674 - Make Inoperative Exemptions; Vehicle Modifications To Accommodate People With Disabilities, Side...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-28

    ... future to meet the pole test requirements is side air bag technology incorporated in the vehicle's roof... air bag technology. The agency explained that, when a vehicle is modified to accommodate a person with... installing side air bags in vehicle seats and/or door panels and side roof rails. The phase-in of...

  8. Simple method for high-performance stretchable composite conductors with entrapped air bubbles.

    PubMed

    Hwang, Hyejin; Kim, Dae-Gon; Jang, Nam-Su; Kong, Jeong-Ho; Kim, Jong-Man

    2016-12-01

    We integrate air bubbles into conductive elastic composite-based stretchable conductors to make them mechanically less stiff and electrically more robust against physical deformations. A surfactant facilitates both the formation and maintenance of air bubbles inside the elastic composites, leading to a simple fabrication of bubble-entrapped stretchable conductors. Based on the unique bubble-entrapped architecture, the elastic properties are greatly enhanced and the resistance change in response to tensile strains can clearly be controlled. The bubble-entrapped conductor achieves ~80 % elongation at ~3.4 times lower stress and ~44.8 % smaller change in the electrical resistance at 80 % tensile strain, compared to bare conductor without air bubbles.

  9. Fetal evaluation for transport by ultrasound performed by air medical teams: A case series.

    PubMed

    Polk, James D; Merlino, James I; Kovach, Betty L; Mancuso, Charlene; Fallon, William F

    2004-01-01

    The air medical team has limited options when evaluating the obstetrical patient and assessing fetal health during air transport to a high-risk obstetrical unit. Traditionally, physical examination and a Doppler stethoscope have been used to determine fetal heart rates and movement. However, with the advent of portable ultrasound technology, new information about the mother and child are available to the air medical crew. The Fetal Evaluation for Transport with Ultrasound (FETUS) is a screening examination that consists of an evaluation of the fetal heart rate, position, and movement and general condition of the placenta. The examination can be repeated in flight with no acoustic distortion from rotor noise. The additional information can be advantageous when transport decisions need to be made or when conditions do not allow Doppler stethoscope use.

  10. Air pollution around schools is linked to poorer student health and academic performance.

    PubMed

    Mohai, Paul; Kweon, Byoung-Suk; Lee, Sangyun; Ard, Kerry

    2011-05-01

    Exposing children to environmental pollutants during important times of physiological development can lead to long-lasting health problems, dysfunction, and disease. The location of children's schools can increase their exposure. We examined the extent of air pollution from industrial sources around public schools in Michigan to find out whether air pollution jeopardizes children's health and academic success. We found that schools located in areas with the highest air pollution levels had the lowest attendance rates-a potential indicator of poor health-and the highest proportions of students who failed to meet state educational testing standards. Michigan and many other states currently do not require officials considering a site for a new school to analyze its environmental quality. Our results show that such requirements are needed. For schools already in existence, we recommend that their environmental quality should be investigated and improved if necessary.

  11. Inflation pressure effect on performance of air-filled wheelchair cushions.

    PubMed

    Krouskop, T A; Williams, R; Noble, P; Brown, J

    1986-02-01

    Air-filled wheelchair cushions are frequently used in the prevention of pressure sores. Their effectiveness in reducing interface pressures and in redistributing body weight (BW) appears dependent on their internal inflation pressure. This pilot study examines and defines this relationship. Interface pressures were measured with the TIPE (Texas Interface Pressure Evaluator) system for 14 subjects while sitting on each of three commercially available air-filled wheelchair cushions. This relationship between interface pressure and internal pressure was then determined for each of the three body-build categories. In each category the interface pressure displayed a higher degree of sensitivity to underinflation than to overinflation. A high correlation found between BW and internal air pressure (IAP), may be useful in the design of a customized pressure indicator system. The study documents the influence of IAP on seating pressure and supports the need for further research in the development of an indicator system that alerts users to under- or overinflation of the cushion.

  12. 18. VIEW OF EAST SIDE INTERIOR OF MST AT STATIONS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    18. VIEW OF EAST SIDE INTERIOR OF MST AT STATIONS 3 AND 12, FACING WEST. COMPRESSED AIR TANK AND GENERATOR AT STATION 3. CURTAIN FOR NORTH ENVIRONMENTAL DOOR VISIBLE ON LEFT SIDE OF PHOTOGRAPH; RAIL VISIBLE AT BOTTOM OF PHOTOGRAPH. - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 East, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

  13. Performance Evaluation of the Operational Air Quality Monitor for Water Testing Aboard the International Space Station

    NASA Technical Reports Server (NTRS)

    Wallace, William T.; Limero, Thomas F.; Gazda, Daniel B.; Macatangay, Ariel V.; Dwivedi, Prabha; Fernandez, Facundo M.

    2014-01-01

    In the history of manned spaceflight, environmental monitoring has relied heavily on archival sampling. For short missions, this type of sample collection was sufficient; returned samples provided a snapshot of the presence of chemical and biological contaminants in the spacecraft air and water. However, with the construction of the International Space Station (ISS) and the subsequent extension of mission durations, soon to be up to one year, the need for enhanced, real-time environmental monitoring became more pressing. The past several years have seen the implementation of several real-time monitors aboard the ISS, complemented with reduced archival sampling. The station air is currently monitored for volatile organic compounds (VOCs) using gas chromatography-differential mobility spectrometry (Air Quality Monitor [AQM]). The water on ISS is analyzed to measure total organic carbon and biocide concentrations using the Total Organic Carbon Analyzer (TOCA) and the Colorimetric Water Quality Monitoring Kit (CWQMK), respectively. The current air and water monitors provide important data, but the number and size of the different instruments makes them impractical for future exploration missions. It is apparent that there is still a need for improvements in environmental monitoring capabilities. One such improvement could be realized by modifying a single instrument to analyze both air and water. As the AQM currently provides quantitative, compound-specific information for target compounds present in air samples, and many of the compounds are also targets for water quality monitoring, this instrument provides a logical starting point to evaluate the feasibility of this approach. In this presentation, we will discuss our recent studies aimed at determining an appropriate method for introducing VOCs from water samples into the gas phase and our current work, in which an electro-thermal vaporization unit has been interfaced with the AQM to analyze target analytes at the

  14. A study of hear sink performance in air and soil for use in a thermoelectric energy harvesting device

    NASA Technical Reports Server (NTRS)

    Snyder, J.; Lawrence, E. E.

    2002-01-01

    A suggested application of a thermoelectric generator is to exploit the natural temperature difference between the air and the soil to generate small amounts of electrical energy. Since the conversion efficiency of even the best thermoelectric generators available is very low, the performance of the heat sinks providing the heat flow is critical. By providing a constant heat input to various heat sinks, field tests of their thermal conductances in soil and in air were performed. Aprototype device without a thermoelectric generator was constructed, buried, and monitored to experimentally measure the heat flow achievable in such a system. Theoretical considerations for design and selection of improved heat sinks are also presented. In particular, the method of shape factoranalysis is used to give rough estimates and upper bounds for the thermal conductance of a passive heat sink buried in soil.

  15. Performance and evaluation of gas-engine-driven split-system cooling equipment at the Willow Grove Naval Air Station

    SciTech Connect

    Armstrong, P.R.; Schmelzer, J.R.

    1997-01-01

    DOE`s Federal Energy Management Program supports efforts to reduce energy use and associated expenditures within the federal sector; one such effort, the New Technology Demonstration Program (NTDP)(formerly the Test Bed Demonstration program), seeks to evaluate new energy saving US technologies and secure their more timely adoption by the federal government. This report describes the field evaluation conducted to examine the performance of a 15-ton natural-gas-engine- driven, split-system, air-conditioning unit. The unit was installed at a multiple-use building at Willow Grove Naval Air Station, a regular and reserve training facility north of Philadelphia, and its performance was monitored under the NTDP.

  16. Conjugate heat transfer investigation on the cooling performance of air cooled turbine blade with thermal barrier coating

    NASA Astrophysics Data System (ADS)

    Ji, Yongbin; Ma, Chao; Ge, Bing; Zang, Shusheng

    2016-08-01

    A hot wind tunnel of annular cascade test rig is established for measuring temperature distribution on a real gas turbine blade surface with infrared camera. Besides, conjugate heat transfer numerical simulation is performed to obtain cooling efficiency distribution on both blade substrate surface and coating surface for comparison. The effect of thermal barrier coating on the overall cooling performance for blades is compared under varied mass flow rate of coolant, and spatial difference is also discussed. Results indicate that the cooling efficiency in the leading edge and trailing edge areas of the blade is the lowest. The cooling performance is not only influenced by the internal cooling structures layout inside the blade but also by the flow condition of the mainstream in the external cascade path. Thermal barrier effects of the coating vary at different regions of the blade surface, where higher internal cooling performance exists, more effective the thermal barrier will be, which means the thermal protection effect of coatings is remarkable in these regions. At the designed mass flow ratio condition, the cooling efficiency on the pressure side varies by 0.13 for the coating surface and substrate surface, while this value is 0.09 on the suction side.

  17. Indoor air pollution and pulmonary performance: Investigating errors in exposure assessment

    SciTech Connect

    Hasabelnaby, N.A.; Ware, J.H.; Fuller, W.A.; Glesser, L.

    1989-01-01

    Pulmonary function measurements on pre-adolescent children and indoor air pollution measurements in the homes of these children are used to illustrate estimation techniques for linear regression models containing independent variables measured with error. In the data set, replicate measures of indoor air pollutant concentrations provide one method of estimating measurement error variances. Surrogate information in the form of cigarettes smoked is also available for the pollutant of interest. Several estimation procedures are presented, and two estimators were combined, one based on surrogate information and one based on replication information, using generalized least squares.

  18. Performance Analysis of a Modular Small-Diameter Air Distribution System

    SciTech Connect

    Poerschke, Andrew; Rudd, Armin

    2016-03-01

    This report investigates the feasibility of using a home-run manifold small-diameter duct system to provide space-conditioning air to individual thermal zones in a low-load home. This compact layout allows duct systems to easily be brought within conditioned space via interior partition walls. Centrally locating the air handling unit in the house significantly reduces duct lengths. The plenum box is designed so that each connected duct receives a similar amount of airflow—regardless of its position on the box. Furthermore, within a reasonable set of length restrictions each duct continues to receive similar airflow.

  19. Performance assessment and characterization of needed IR GEO instruments to monitor air quality

    NASA Astrophysics Data System (ADS)

    Sellitto, P.; Dauphin, P.; Dufour, G.; Eremenko, M.; Cuesta, J.; Coman, A.; Forêt, G.; Beekmann, M.; Peuch, V.; Flaud, J.

    2011-12-01

    Efficiently monitoring air quality (AQ) from space is a valuable step forward towards a more thorough comprehension of pollution processes that can have a relevant impact on the biosphere. In recent years, important progresses in the field of atmospheric sounding from space have been made, e.g., reliable observations of several pollutants have been obtained, proving the feasibility of monitoring atmospheric composition from space. In this sense, low Earth orbit (LEO) thermal infrared (TIR) space-borne instruments are widely regarded as a useful tool to observe targeted AQ parameters like tropospheric ozone concentrations. However, limitations remain with the current observation systems in particular to observe ozone in the lowermost troposphere (LmT) with a spatial and temporal resolution relevant for monitoring pollution processes at the regional scale. Indeed, LEO instruments are not well adapted to monitor small scale and short term phenomena, owing to their unsatisfactory revisit time. From this point of view, a more satisfactory concept might be based on geostationary Earth orbit (GEO) platforms. Current and planned GEO missions are mainly tailored on meteorological parameters retrieval and do not have sufficient spectral resolutions and signal to noise ratios (SNR) to infer information on trace gases in the LmT. New satellite missions are currently proposed that can partly overcome these limitations. Here we present a group of simulation exercises and sensitivity analyses to set-up future TIR GEO missions adapted to monitor and forecast AQ over Europe, and to evaluate their technical requirements. At this aim, we have developed a comprehensive simulator to produce pseudo-observations for different platform/instrument configurations. The core of this simulator is the KOPRA radiative transfer model, including the KOPRAFIT inversion module. Note that to assess the impact of the different instruments on the analyses and forecasts of AQ by means of models, our

  20. Performance assessment of future thermal infrared geostationary instruments to monitor air quality

    NASA Astrophysics Data System (ADS)

    Sellitto, P.; Dauphin, P.; Dufour, G.; Eremenko, M.; Cuesta, J.; Coman, A.; Forêt, G.; Beekmann, M.; Gaubert, B.; Flaud, J.-M.

    2012-04-01

    Air quality (AQ) has a recognized onerous impact on human health and the environment, and then on society. It is more and more clear that constantly and efficiently monitoring AQ from space is a valuable step forward towards a more thorough comprehension of pollution processes that can have a relevant impact on the biosphere. In recent years, important progresses in this field have been made, e.g., reliable observations of several pollutants have been obtained, proving the feasibility of monitoring atmospheric composition from space. In this sense, low Earth orbit (LEO) thermal infrared (TIR) space-borne instruments are widely regarded as a useful tool to observe targeted AQ parameters like tropospheric ozone concentrations [1]. However, limitations remain with the current observation systems in particular to observe ozone in the lowermost troposphere (LmT) with a spatial and temporal resolution relevant for monitoring pollution processes at the regional scale. Indeed, LEO instruments are not well adapted to monitor small scale and short term phenomena, owing to their unsatisfactory revisit time. From this point of view, a more satisfactory concept might be based on geostationary (GEO) platforms. Current and planned GEO missions are mainly tailored on meteorological parameters retrieval and do not have sufficient spectral resolutions and signal to noise ratios (SNR) to infer information on trace gases in the LmT. New satellite missions are currently proposed that can partly overcome these limitations. Here we present a group of simulation exercises and sensitivity analyses to set-up future TIR GEO missions adapted to monitor and forecast AQ over Europe, and to evaluate their technical requirements. At this aim, we have developed a general simulator to produce pseudo-observations for different platform/instrument configurations. The core of this simulator is the KOPRA radiative transfer model, including the KOPRAfit inversion module [2]. Note that to assess the

  1. Effect of air-entry angle on performance of a 2-stroke-cycle compression-ignition engine

    NASA Technical Reports Server (NTRS)

    Earle, Sherod L; Dutee, Francis J

    1937-01-01

    An investigation was made to determine the effect of variations in the horizontal and vertical air-entry angles on the performance characteristics of a single-cylinder 2-stroke-cycle compression-ignition test engine. Performance data were obtained over a wide range of engine speed, scavenging pressure, fuel quantity, and injection advance angle with the optimum guide vanes. Friction and blower-power curves are included for calculating the indicated and net performances. The optimum horizontal air-entry angle was found to be 60 degrees from the radial and the optimum vertical angle to be zero, under which conditions a maximum power output of 77 gross brake horsepower for a specific fuel consumption of 0.52 pound per brake horsepower-hour was obtained at 1,800 r.p.m. and 16-1/2 inches of Hg scavenging pressure. The corresponding specific output was 0.65 gross brake horsepower per cubic inch of piston displacement. Tests revealed that the optimum scavenging pressure increased linearly with engine speed. The brake mean effective pressure increased uniformly with air quantity per cycle for any given vane angle and was independent of engine speed and scavenging pressure.

  2. Novel prescribed performance neural control of a flexible air-breathing hypersonic vehicle with unknown initial errors.

    PubMed

    Bu, Xiangwei; Wu, Xiaoyan; Zhu, Fujing; Huang, Jiaqi; Ma, Zhen; Zhang, Rui

    2015-11-01

    A novel prescribed performance neural controller with unknown initial errors is addressed for the longitudinal dynamic model of a flexible air-breathing hypersonic vehicle (FAHV) subject to parametric uncertainties. Different from traditional prescribed performance control (PPC) requiring that the initial errors have to be known accurately, this paper investigates the tracking control without accurate initial errors via exploiting a new performance function. A combined neural back-stepping and minimal learning parameter (MLP) technology is employed for exploring a prescribed performance controller that provides robust tracking of velocity and altitude reference trajectories. The highlight is that the transient performance of velocity and altitude tracking errors is satisfactory and the computational load of neural approximation is low. Finally, numerical simulation results from a nonlinear FAHV model demonstrate the efficacy of the proposed strategy.

  3. Performance of the Proposed New Federal Reference Methods for Measuring Ozone Concentrations in Ambient Air

    EPA Science Inventory

    The current Federal Reference Method (FRM) for measuring concentrations of ozone in ambient air, described in EPA regulations at 40 CFR Part 50, Appendix D, is based on the dry, gas-phase, chemiluminescence reaction between ethylene (C2H4) and any ozone (O

  4. Environmental Learning Workshop: Lichen as Biological Indicator of Air Quality and Impact on Secondary Students' Performance

    ERIC Educational Resources Information Center

    Samsudin, Mohd Wahid; Daik, Rusli; Abas, Azlan; Meerah, T. Subahan Mohd; Halim, Lilia

    2013-01-01

    In this study, the learning of science outside the classroom is believe to be an added value to science learning as well as it offers students to interact with the environment. This study presents data obtained from two days' workshop on Lichen as Biological Indicator for Air Quality. The aim of the workshop is for the students to gain an…

  5. EVALUATION OF TRICKLE-BED AIR BIOFILTER PERFORMANCE FOR STYRENE REMOVAL

    EPA Science Inventory

    A pilot-scale trickle-bed air biofilter (TBAB) was evaluated for the removal of styrene from a waste gas stream. Six-millimeter (6 mm) Celite pellets (R-635) were used as the biological attachment medium. The operating parameters considered in the study included the styrene vol...

  6. Experience-Based Mitigation of Age-Related Performance Declines: Evidence from Air Traffic Control

    ERIC Educational Resources Information Center

    Nunes, Ashley; Kramer, Arthur F.

    2009-01-01

    Previous research has found age-related deficits in a variety of cognitive processes. However, some studies have demonstrated age-related sparing on tasks where individuals have substantial experience, often attained over many decades. Here, the authors examined whether decades of experience in a fast-paced demanding profession, air traffic…

  7. 16 CFR Appendix H to Part 305 - Cooling Performance and Cost for Central Air Conditioners

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Conditioners (Cooling Only): All capacities 10.6 16.5 Heat Pumps (Cooling Function): All capacities 10.6 16.0 Split System Units Central Air Conditioners (Cooling Only): All capacities 10.9 23.0 Heat Pumps...

  8. THE NEW ENGLAND AIR QUALITY FORECASTING PILOT PROGRAM: DEVELOPMENT OF AN EVALUATION PROTOCOL AND PERFORMANCE BENCHMARK

    EPA Science Inventory

    The National Oceanic and Atmospheric Administration recently sponsored the New England Forecasting Pilot Program to serve as a "test bed" for chemical forecasting by providing all of the elements of a National Air Quality Forecasting System, including the development and implemen...

  9. Assessing the Feasibility of Performing an Air Accountability Study in New Haven, CT

    EPA Science Inventory

    The main objective of this EPA study was to examine the feasibility of conducting a local (e.g., city level) assessment of the public health impacts of cumulative air pollution reduction activities (a.k.a. accountability) from the federal, state, local and voluntary actions in t...

  10. 16 CFR Appendix H to Part 305 - Cooling Performance and Cost for Central Air Conditioners

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Conditioners (Cooling Only): All capacities 10.6 16.5 Heat Pumps (Cooling Function): All capacities 10.6 16.0 Split System Units Central Air Conditioners (Cooling Only): All capacities 10.9 23.0 Heat Pumps...

  11. 16 CFR Appendix H to Part 305 - Cooling Performance and Cost for Central Air Conditioners

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Conditioners (Cooling Only): All capacities 10.6 16.5 Heat Pumps (Cooling Function): All capacities 10.6 16.0 Split System Units Central Air Conditioners (Cooling Only): All capacities 10.9 23.0 Heat Pumps...

  12. 16 CFR Appendix H to Part 305 - Cooling Performance and Cost for Central Air Conditioners

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Conditioners (Cooling Only): All capacities 10.6 16.5 Heat Pumps (Cooling Function): All capacities 10.6 16.0 Split System Units Central Air Conditioners (Cooling Only): All capacities 10.9 23.0 Heat Pumps...

  13. Painting as Rhetorical Performance: Joseph Wright's "An Experiment on a Bird in the Air Pump."

    ERIC Educational Resources Information Center

    Helmers, Marguerite

    2001-01-01

    Explores three broad areas of inquiry: what significance visual images have for rhetorical analysis; how a study of nonverbal material might be conducted; and whether visual explanations depend on the image or the viewer. Argues that viewers understand Joseph Wright's painting "The Air Pump" in terms of its subject, its exhibition space, the…

  14. 132. WEST SIDE OF MECHANICAL AND ELECTRICAL ROOM (210), LSB ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    132. WEST SIDE OF MECHANICAL AND ELECTRICAL ROOM (210), LSB (BLDG. 751), QUALITY CONTROL BOARD ON LEFT. SOUTH SIDE OF TRANSFORMER ROOM (212) ON RIGHT SIDE OF PHOTOGRAPH, THROUGH OPEN DOORS. - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 East, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

  15. Impact of Charge Degradation on the Life Cycle Climate Performance of a Residential Air-Conditioning System

    SciTech Connect

    Beshr, Mohamed; Aute, Vikrant; Abdelaziz, Omar; Fricke, Brian A; Radermacher, Reinhard

    2014-01-01

    Vapor compression systems continuously leak a small fraction of their refrigerant charge to the environment, whether during operation or servicing. As a result of the slow leak rate occurring during operation, the refrigerant charge decreases until the system is serviced and recharged. This charge degradation, after a certain limit, begins to have a detrimental effect on system capacity, energy consumption, and coefficient of performance (COP). This paper presents a literature review and a summary of previous experimental work on the effect of undercharging or charge degradation of different vapor compression systems, especially those without a receiver. These systems include residential air conditioning and heat pump systems utilizing different components and refrigerants, and water chiller systems. Most of these studies show similar trends for the effect of charge degradation on system performance. However, it is found that although much experimental work exists on the effect of charge degradation on system performance, no correlation or comparison between charge degradation and system performance yet exists. Thus, based on the literature review, three different correlations that characterize the effect of charge on system capacity and energy consumption are developed for different systems as follows: one for air-conditioning systems, one for vapor compression water-to-water chiller systems, and one for heat pumps. These correlations can be implemented in vapor compression cycle simulation tools to obtain a better prediction of the system performance throughout its lifetime. In this paper, these correlations are implemented in an open source tool for life cycle climate performance (LCCP) based design of vapor compression systems. The LCCP of a residential air-source heat pump is evaluated using the tool and the effect of charge degradation on the results is studied. The heat pump is simulated using a validated component-based vapor compression system model and

  16. Artificial intelligence modeling to evaluate field performance of photocatalytic asphalt pavement for ambient air purification.

    PubMed

    Asadi, Somayeh; Hassan, Marwa; Nadiri, Ataallah; Dylla, Heather

    2014-01-01

    In recent years, the application of titanium dioxide (TiO₂) as a photocatalyst in asphalt pavement has received considerable attention for purifying ambient air from traffic-emitted pollutants via photocatalytic processes. In order to control the increasing deterioration of ambient air quality, urgent and proper risk assessment tools are deemed necessary. However, in practice, monitoring all process parameters for various operating conditions is difficult due to the complex and non-linear nature of air pollution-based problems. Therefore, the development of models to predict air pollutant concentrations is very useful because it can provide early warnings to the population and also reduce the number of measuring sites. This study used artificial neural network (ANN) and neuro-fuzzy (NF) models to predict NOx concentration in the air as a function of traffic count (Tr) and climatic conditions including humidity (H), temperature (T), solar radiation (S), and wind speed (W) before and after the application of TiO₂ on the pavement surface. These models are useful for modeling because of their ability to be trained using historical data and because of their capability for modeling highly non-linear relationships. To build these models, data were collected from a field study where an aqueous nano TiO₂ solution was sprayed on a 0.2-mile of asphalt pavement in Baton Rouge, LA. Results of this study showed that the NF model provided a better fitting to NOx measurements than the ANN model in the training, validation, and test steps. Results of a parametric study indicated that traffic level, relative humidity, and solar radiation had the most influence on photocatalytic efficiency.

  17. Performance Optimization of an Air-Standard Irreversible Dual-Atkinson Cycle Engine Based on the Ecological Coefficient of Performance Criterion

    PubMed Central

    Gonca, Guven; Sahin, Bahri

    2014-01-01

    This paper presents an ecological performance analysis and optimization for an air-standard irreversible Dual-Atkinson cycle (DAC) based on the ecological coefficient of performance (ECOP) criterion which includes internal irreversibilities, heat leak, and finite-rate of heat transfer. A comprehensive numerical analysis has been realized so as to investigate the global and optimal performances of the cycle. The results obtained based on the ECOP criterion are compared with a different ecological function which is named as the ecologic objective-function and with the maximum power output conditions. The results have been attained introducing the compression ratio, cut-off ratio, pressure ratio, Atkinson cycle ratio, source temperature ratio, and internal irreversibility parameter. The change of cycle performance with respect to these parameters is investigated and graphically presented. PMID:25170525

  18. Performance and diagnostic evaluation of ozone predictions by the Eta-Community Multiscale Air Quality Forecast System during the 2002 New England Air Quality Study.

    PubMed

    Yu, Shaocai; Mathur, Rohit; Kang, Daiwen; Schere, Kenneth; Eder, Brian; Pleim, Jonathan

    2006-10-01

    A real-time air quality forecasting system (Eta-Community Multiscale Air Quality [CMAQ] model suite) has been developed by linking the National Centers for Environmental Estimation Eta model to the U.S. Environmental Protection Agency (EPA) CMAQ model. This work presents results from the application of the Eta-CMAQ modeling system for forecasting ozone (O3) over the Northeastern United States during the 2002 New England Air Quality Study (NEAQS). Spatial and temporal performance of the Eta-CMAQ model for O3 was evaluated by comparison with observations from the EPA Air Quality System (AQS) network. This study also examines the ability of the model to simulate the processes governing the distributions of tropospheric O3 on the basis of the intensive datasets obtained at the four Atmospheric Investigation, Regional Modeling, Analysis, and Estimation (AIRMAP) and Harvard Forest (HF) surface sites. The episode analysis reveals that the model captured the buildup of O3 concentrations over the northeastern domain from August 11 and reproduced the spatial distributions of observed O3 very well for the daytime (8:00 p.m.) of both August 8 and 12 with most of normalized mean bias (NMB) within +/- 20%. The model reproduced 53.3% of the observed hourly O3 within a factor of 1.5 with NMB of 29.7% and normalized mean error of 46.9% at the 342 AQS sites. The comparison of modeled and observed lidar O3 vertical profiles shows that whereas the model reproduced the observed vertical structure, it tended to overestimate at higher altitude. The model reproduced 64-77% of observed NO2 photolysis rate values within a factor of 1.5 at the AIRMAP sites. At the HF site, comparison of modeled and observed O3/nitrogen oxide (NOx) ratios suggests that the site is mainly under strongly NOx-sensitive conditions (>53%). It was found that the modeled lower limits of the O3 production efficiency values (inferred from O3-CO correlation) are close to the observations.

  19. Enhanced performance of an air-cathode microbial fuel cell with oxygen supply from an externally connected algal bioreactor.

    PubMed

    Kakarla, Ramesh; Kim, Jung Rae; Jeon, Byong-Hun; Min, Booki

    2015-11-01

    An algae bioreactor (ABR) was externally connected to air-cathode microbial fuel cells (MFCs) to increase power generation by supplying a high amount of oxygen to cathode electrode. The MFC with oxygen fed from ABR produced maximum cell voltage and cathode potential at a fixed loading of 459 mV and 10 mV, respectively. During polarization analysis, the MFC displayed a maximum power density of 0.63 W/m(2) (at 2.06 A/m(2)) using 39.2% O2 from ABR, which was approximately 30% higher compared with use of atmospheric air (0.44 W/m(2), 20.8% O2,). The cyclic voltammogram analysis exhibited a higher reduction current of -137 mA with 46.5% O2 compared to atmospheric air (-115 mA). Oxygen supply by algae bioreactor to air-cathode MFC could also maintain better MFC performance in long term operation by minimizing cathode potential drop over time.

  20. Assessing the performance of standard methods to predict the standard uncertainty of air quality data having incomplete time coverage.

    PubMed

    Brown, Richard J C; Harris, Peter M; Cox, Maurice G

    2014-07-01

    As a result of the complex nature of operating multi-station national air quality networks it is rare that complete data sets are produced from these networks. The reliance of most air quality legislation on the assessment of measured annual average concentrations against target or limit concentrations necessitates the use of methods to calculate an annual average value and the uncertainty in this value in the absence of a complete data set for the year in question. Standard procedures exist for performing these calculations, but it is not clear how effective these are when data having low time resolution are collected and missing data accounts for large periods of the year. This paper investigates the influence of these deficiencies using data from UK air quality networks in the form of monthly average concentrations for polycyclic aromatic hydrocarbons and for metals in the PM10 phase of ambient air. Whilst the standard methods currently employed produce good results on average, for individual cases the uncertainty in the annual average calculated when data is missing may be appreciably different from that obtained when full knowledge of the distribution of the data is known. These effects become more apparent as the quantity of missing data increases.