Science.gov

Sample records for air delivery rate

  1. Whole house particle removal and clean air delivery rates for in-duct and portable ventilation systems.

    PubMed

    Macintosh, David L; Myatt, Theodore A; Ludwig, Jerry F; Baker, Brian J; Suh, Helen H; Spengler, John D

    2008-11-01

    A novel method for determining whole house particle removal and clean air delivery rates attributable to central and portable ventilation/air cleaning systems is described. The method is used to characterize total and air-cleaner-specific particle removal rates during operation of four in-duct air cleaners and two portable air-cleaning devices in a fully instrumented test home. Operation of in-duct and portable air cleaners typically increased particle removal rates over the baseline rates determined in the absence of operating a central fan or an indoor air cleaner. Removal rates of 0.3- to 0.5-microm particles ranged from 1.5 hr(-1) during operation of an in-duct, 5-in. pleated media filter to 7.2 hr(-1) for an in-duct electrostatic air cleaner in comparison to a baseline rate of 0 hr(-1) when the air handler was operating without a filter. Removal rates for total particulate matter less than 2.5 microm in aerodynamic diameter (PM2.5) mass concentrations were 0.5 hr(-1) under baseline conditions, 0.5 hr(-1) during operation of three portable ionic air cleaners, 1 hr(-1) for an in-duct 1-in. media filter, 2.4 hr(-1) for a single high-efficiency particle arrestance (HEPA) portable air cleaner, 4.6 hr(-1) for an in-duct 5-in. media filter, 4.7 hr(-1) during operation of five portable HEPA filters, 6.1 hr(-1) for a conventional in-duct electronic air cleaner, and 7.5 hr(-1) for a high efficiency in-duct electrostatic air cleaner. Corresponding whole house clean air delivery rates for PM2.5 attributable to the air cleaner independent of losses within the central ventilation system ranged from 2 m3/min for the conventional media filter to 32 m3/min for the high efficiency in-duct electrostatic device. Except for the portable ionic air cleaner, the devices considered here increased particle removal indoors over baseline deposition rates.

  2. Determination of the Clean Air Delivery Rate (CADR) of Photocatalytic Oxidation (PCO) Purifiers for Indoor Air Pollutants Using a Closed-Loop Reactor. Part I: Theoretical Considerations.

    PubMed

    Dumont, Éric; Héquet, Valérie

    2017-03-06

    This study demonstrated that a laboratory-scale recirculation closed-loop reactor can be an efficient technique for the determination of the Clean Air Delivery Rate (CADR) of PhotoCatalytic Oxidation (PCO) air purification devices. The recirculation closed-loop reactor was modeled by associating equations related to two ideal reactors: one is a perfectly mixed reservoir and the other is a plug flow system corresponding to the PCO device itself. Based on the assumption that the ratio between the residence time in the PCO device and the residence time in the reservoir τP/τR tends to 0, the model highlights that a lab closed-loop reactor can be a suitable technique for the determination of the efficiency of PCO devices. Moreover, if the single-pass removal efficiency is lower than 5% of the treated flow rate, the decrease in the pollutant concentration over time can be characterized by a first-order decay model in which the time constant is proportional to the CADR. The limits of the model are examined and reported in terms of operating conditions (experiment duration, ratio of residence times, and flow rate ranges).

  3. Determination of the Clean Air Delivery Rate (CADR) of Photocatalytic Oxidation (PCO) Purifiers for Indoor Air Pollutants Using a Closed-Loop Reactor. Part II: Experimental Results.

    PubMed

    Héquet, Valérie; Batault, Frédéric; Raillard, Cécile; Thévenet, Frédéric; Le Coq, Laurence; Dumont, Éric

    2017-03-06

    The performances of a laboratory PhotoCatalytic Oxidation (PCO) device were determined using a recirculation closed-loop pilot reactor. The closed-loop system was modeled by associating equations related to two ideal reactors: a perfectly mixed reservoir with a volume of VR = 0.42 m³ and a plug flow system corresponding to the PCO device with a volume of VP = 5.6 × 10(-3) m³. The PCO device was composed of a pleated photocatalytic filter (1100 cm²) and two 18-W UVA fluorescent tubes. The Clean Air Delivery Rate (CADR) of the apparatus was measured under different operating conditions. The influence of three operating parameters was investigated: (i) light irradiance I from 0.10 to 2.0 mW·cm(-2); (ii) air velocity v from 0.2 to 1.9 m·s(-1); and (iii) initial toluene concentration C₀ (200, 600, 1000 and 4700 ppbv). The results showed that the conditions needed to apply a first-order decay model to the experimental data (described in Part I) were fulfilled. The CADR values, ranging from 0.35 to 3.95 m³·h(-1), were mainly dependent on the light irradiance intensity. A square root influence of the light irradiance was observed. Although the CADR of the PCO device inserted in the closed-loop reactor did not theoretically depend on the flow rate (see Part I), the experimental results did not enable the confirmation of this prediction. The initial concentration was also a parameter influencing the CADR, as well as the toluene degradation rate. The maximum degradation rate rmax ranged from 342 to 4894 ppbv/h. Finally, this study evidenced that a recirculation closed-loop pilot could be used to develop a reliable standard test method to assess the effectiveness of PCO devices.

  4. Submicrometer particle removal indoors by a novel electrostatic precipitator with high clean air delivery rate, low ozone emissions, and carbon fiber ionizer.

    PubMed

    Kim, H-J; Han, B; Kim, Y-J; Oda, T; Won, H

    2013-10-01

    A novel positive-polarity electrostatic precipitator (ESP) was developed using an ionization stage (0.4 × 0.4 × 0.14 m(3) ) with 16 carbon fiber ionizers in each channel and a collection stage (0.4 × 0.4 × 0.21 m(3) ) with parallel metallic plates. The single-pass collection efficiency and clean air delivery rate (CADR) were measured by standard tests using KCl particles in 0.25-0.35 μm. Performance was determined using the Deutsch equation and established diffusion and field charging theories and also compared with the commercialized HEPA filter-type air cleaner. Experimental results showed that the single-pass collection efficiency of the ESP ranged from 50 to 95% and decreased with the flow rate (10-20 m(3) /min), but increased with the voltage applied to the ionizers (6 to 8 kV) and collection plates (-5 to -7 kV). The ESP with 18 m(3) /min achieved a CADR of 12.1 m(3) /min with a voltage of 8 kV applied to the ionization stage and with a voltage of -6 kV applied to the collection stage. The concentration of ozone in the test chamber (30.4 m(3) ), a maximum value of 5.4 ppb over 12 h of continuous operation, was much lower than the current indoor regulation (50 ppb).

  5. Cesarean section delivery rates: United States, 1981.

    PubMed Central

    Placek, P J; Taffel, S; Moien, M

    1983-01-01

    The rate of cesarean section delivery in the United States has risen from 4.5 per 100 deliveries in 1965 to 17.9 in 1981. The rate is highest in the Northeast, in hospitals of 500 beds or more, in proprietary hospitals, for Blue Cross as a source of payment, and for mothers aged 35 years and over. The rate is lowest in the North Central region, in hospitals with less than 100 beds, in government hospitals, for self-pay patients, and for mothers under 20 years of age. PMID:6869638

  6. 36 CFR 2.17 - Aircraft and air delivery.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Aircraft and air delivery. 2... RESOURCE PROTECTION, PUBLIC USE AND RECREATION § 2.17 Aircraft and air delivery. (a) The following are prohibited: (1) Operating or using aircraft on lands or waters other than at locations designated pursuant...

  7. 36 CFR 1002.17 - Aircraft and air delivery.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 36 Parks, Forests, and Public Property 3 2012-07-01 2012-07-01 false Aircraft and air delivery... USE AND RECREATION § 1002.17 Aircraft and air delivery. (a) Delivering or retrieving a person or... business of the Federal government, or emergency rescues in accordance with the directions of the...

  8. 36 CFR 2.17 - Aircraft and air delivery.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 1 2011-07-01 2011-07-01 false Aircraft and air delivery. 2... RESOURCE PROTECTION, PUBLIC USE AND RECREATION § 2.17 Aircraft and air delivery. (a) The following are prohibited: (1) Operating or using aircraft on lands or waters other than at locations designated pursuant...

  9. 36 CFR 1002.17 - Aircraft and air delivery.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false Aircraft and air delivery... USE AND RECREATION § 1002.17 Aircraft and air delivery. (a) Delivering or retrieving a person or... business of the Federal government, or emergency rescues in accordance with the directions of the...

  10. 36 CFR 1002.17 - Aircraft and air delivery.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 36 Parks, Forests, and Public Property 3 2013-07-01 2012-07-01 true Aircraft and air delivery... USE AND RECREATION § 1002.17 Aircraft and air delivery. (a) Delivering or retrieving a person or... business of the Federal government, or emergency rescues in accordance with the directions of the...

  11. 36 CFR 1002.17 - Aircraft and air delivery.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 36 Parks, Forests, and Public Property 3 2014-07-01 2014-07-01 false Aircraft and air delivery... USE AND RECREATION § 1002.17 Aircraft and air delivery. (a) Delivering or retrieving a person or... business of the Federal government, or emergency rescues in accordance with the directions of the...

  12. 36 CFR 2.17 - Aircraft and air delivery.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 36 Parks, Forests, and Public Property 1 2014-07-01 2014-07-01 false Aircraft and air delivery. 2... RESOURCE PROTECTION, PUBLIC USE AND RECREATION § 2.17 Aircraft and air delivery. (a) The following are prohibited: (1) Operating or using aircraft on lands or waters other than at locations designated pursuant...

  13. 36 CFR 2.17 - Aircraft and air delivery.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 36 Parks, Forests, and Public Property 1 2012-07-01 2012-07-01 false Aircraft and air delivery. 2... RESOURCE PROTECTION, PUBLIC USE AND RECREATION § 2.17 Aircraft and air delivery. (a) The following are prohibited: (1) Operating or using aircraft on lands or waters other than at locations designated pursuant...

  14. 36 CFR 1002.17 - Aircraft and air delivery.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 3 2011-07-01 2011-07-01 false Aircraft and air delivery... USE AND RECREATION § 1002.17 Aircraft and air delivery. (a) Delivering or retrieving a person or... in paragraph (c)(3) of this section, the owners of a downed aircraft shall remove the aircraft...

  15. 36 CFR 2.17 - Aircraft and air delivery.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 36 Parks, Forests, and Public Property 1 2013-07-01 2013-07-01 false Aircraft and air delivery. 2... RESOURCE PROTECTION, PUBLIC USE AND RECREATION § 2.17 Aircraft and air delivery. (a) The following are prohibited: (1) Operating or using aircraft on lands or waters other than at locations designated pursuant...

  16. The Flying Newsboy: A Small Daily Attempts Air Delivery.

    ERIC Educational Resources Information Center

    Watts, Elizabeth A.

    For 10 months in 1929-30, subscribers to "The McCook (Nebraska) Daily Gazette" (a daily newspaper serving 33 towns in southwestern Nebraska and northwestern Kansas) received their newspapers via air delivery with "The Newsboy," a Curtis Robin cabin monoplane. In an age when over-the-road travel was difficult and air travel was…

  17. Venous Air Embolism during Surgery, Especially Cesarean Delivery

    PubMed Central

    Kim, Chang Seok; Liu, Jia; Kwon, Ja-Young; Shin, Seo Kyung

    2008-01-01

    Venous air embolism (VAE) is the entrapment of air or medical gases into the venous system causing symptoms and signs of pulmonary vessel obstruction. The incidence of VAE during cesarean delivery ranges from 10 to 97% depending on surgical position or diagnostic tools, with a potential for life-threatening events. We reviewed extensive literatures regarding VAE in detail and herein described VAE during surgery including cesarean delivery from background and history to treatment and prevention. It is intended that present work will improve the understanding of VAE during surgery. PMID:18955777

  18. Caesarean Delivery Rate Review: An Evidence-Based Analysis

    PubMed Central

    Degani, N; Sikich, N

    2015-01-01

    Background In 2007, caesarean deliveries comprised 28% of all hospital deliveries in Ontario. Provincial caesarean delivery rates increased with maternal age and varied by Local Health Integration Network. However, the accepted rate of caesarean delivery in a low-risk maternal population remains unclear. Objectives To review the literature to assess factors that affect the likelihood of experiencing a caesarean delivery, and to examine Ontario caesarean delivery rates to determine whether there is rate variation across the province. Data Sources Data sources included publications from OVID MEDLINE, OVID MEDLINE In-Process and Other Non-Indexed Citations, OVID Embase, EBSCO Cumulative Index to Nursing & Allied Health Literature (CINAHL), and EBM Reviews, as well as data from the Canadian Institute for Health Information Discharge Abstracts Database and the Better Outcomes and Registry Network. Review Methods A mixed-methods approach was used, which included a systematic review of the literature to delineate factors associated with the likelihood of caesarean delivery and an analysis of administrative and clinical data on hospital deliveries in Ontario to determine provincial caesarean delivery rates, variation in rates, and reasons for variation. Results Fourteen systematic reviews assessed 14 factors affecting the likelihood of caesarean delivery; 7 factors were associated with an increased likelihood of caesarean delivery, and 2 factors were associated with a decreased likelihood. Five factors had no influence. One factor provided moderate-quality evidence supporting elective induction policies in low-risk women. The overall Ontario caesarean delivery rate in a very-low-risk population was 17%, but varied significantly across Ontario hospitals. Limitations The literature review included a 5–year period and used only systematic reviews. The determination of Robson class for women is based on care received in hospital only, and the low-risk population may have

  19. Air Delivery and Marine Corps Logistics

    DTIC Science & Technology

    2010-03-17

    to ground-based logistics, the evolution of ground-based vehicles to counter the threat, and the lift capacity of air and ground vehicles organic to...UAS------------------------------------------- A4 Figure 11. Bo.eing A160 Hummingbird Vertical Lift UAS------------------------------------------- A4...Vertical Takeoff and Landing Unmanned Aerial Vehicle (VTUAV). VTUAVs like the Boeing A160 Hummingbird , Bell Helicopter Eagle Eye, and the Northrop

  20. Plasma-activated air mediates plasmid DNA delivery in vivo

    PubMed Central

    Edelblute, Chelsea M; Heller, Loree C; Malik, Muhammad A; Bulysheva, Anna; Heller, Richard

    2016-01-01

    Plasma-activated air (PAA) provides a noncontact DNA transfer platform. In the current study, PAA was used for the delivery of plasmid DNA in a 3D human skin model, as well as in vivo. Delivery of plasmid DNA encoding luciferase to recellularized dermal constructs was enhanced, resulting in a fourfold increase in luciferase expression over 120 hours compared to injection only (P < 0.05). Delivery of plasmid DNA encoding green fluorescent protein (GFP) was confirmed in the epidermal layers of the construct. In vivo experiments were performed in BALB/c mice, with skin as the delivery target. PAA exposure significantly enhanced luciferase expression levels 460-fold in exposed sites compared to levels obtained from the injection of plasmid DNA alone (P < 0.001). Expression levels were enhanced when the plasma reactor was positioned more distant from the injection site. Delivery of plasmid DNA encoding GFP to mouse skin was confirmed by immunostaining, where a 3-minute exposure at a 10 mm distance displayed delivery distribution deep within the dermal layers compared to an exposure at 3 mm where GFP expression was localized within the epidermis. Our findings suggest PAA-mediated delivery warrants further exploration as an alternative approach for DNA transfer for skin targets. PMID:27110584

  1. [The effect of air within the infusion syringe on drug delivery of syringe pump infusion systems] .

    PubMed

    Schulz, G; Fischer, J; Neff, T; Bänziger, O; Weiss, M

    2000-12-01

    Application of highly concentrated short-acting vasoactive drugs in the critically ill patient requires precisely working syringe pump systems for continuous intravenous drug delivery. We performed a bench study to investigate the consequences of small amounts of air entrapped within a 50-ml infusion syringe. In particular we studied the effect of entrapped air on drug delivery after moderate vertical displacement of the pump by 50 cm (e.g. in preparation for transport) and the effect on the time required to trigger the pressure alarm after occlusion of the infusion line. At a flow rate of 1 ml/h, lowering the syringe pump prolonged the zero-drug delivery time from (mean +/- SD) 4.1 +/- 0.8 min (without air) to 6.2 +/- 0.9 (with 1 ml air) and to 13.1 +/- 0.9 min (with 2 ml of air, p < 0.001 for all comparisons). Entrapping of 2 ml of air within the syringe resulted in a 2.6-fold prolongation of the occlusion alarm time after accidental occlusion of the infusion line and a 3-fold increase of the resulting infusion bolus after occlusion. Enclosed air within infusion syringes considerably affects the syringe compliance. It increases the susceptibility of constant drug delivery to vertical displacement of syringe pumps and impairs the occlusion alarm function. Therefore, any air in syringe of infusion pump systems should be carefully removed. To avoid infusion boluses of short-acting vasoactive drugs after accidental occlusions, the occluded infusion line should be released to ambient pressure first.

  2. Air Vehicles Technology Integration Program (AVTIP). Delivery Order 0020: Prediction of Manufacturing Tolerances for Laminar Flow

    DTIC Science & Technology

    2005-06-01

    AFRL-VA-WP-TR-2005-3060 AIR VEHICLES TECHNOLOGY INTEGRATION PROGRAM (AVTIP) Delivery Order 0020 : Prediction Of... Technology Integration Program (AVTIP) 5b. GRANT NUMBER Delivery Order 0020 : Prediction Of Manufacturing Tolerances For Laminar Flow 5c. PROGRAM

  3. Thermodynamic Vent System Applied as Propellant Delivery System for Air Force

    NASA Technical Reports Server (NTRS)

    1996-01-01

    Responding to a request from the Air Force, NASA Lewis Research Center engineers designed a combination pressure control and propellant delivery system based on thermodynamic vent system (TVS) technology. The Air Force is designing a new type of orbit transfer vehicle that uses energy from sunlight to both propel and power the vehicle. Because this vehicle uses propellant at a substantially slower rate than higher-energy rockets, it needed the Lewis-developed TVS technology for long-duration storage of cryogen propellants. Lewis engineers, in conjunction with industry partners, showed how this TVS technology could also be used to deliver propellant to the thruster. The Air Force has now begun the ground test demonstration phase. After successful completion of ground testing, the Air Force plans to use this technology in a space flight as early as 1999.

  4. Technological Advancements and Error Rates in Radiation Therapy Delivery

    SciTech Connect

    Margalit, Danielle N.

    2011-11-15

    Purpose: Technological advances in radiation therapy (RT) delivery have the potential to reduce errors via increased automation and built-in quality assurance (QA) safeguards, yet may also introduce new types of errors. Intensity-modulated RT (IMRT) is an increasingly used technology that is more technically complex than three-dimensional (3D)-conformal RT and conventional RT. We determined the rate of reported errors in RT delivery among IMRT and 3D/conventional RT treatments and characterized the errors associated with the respective techniques to improve existing QA processes. Methods and Materials: All errors in external beam RT delivery were prospectively recorded via a nonpunitive error-reporting system at Brigham and Women's Hospital/Dana Farber Cancer Institute. Errors are defined as any unplanned deviation from the intended RT treatment and are reviewed during monthly departmental quality improvement meetings. We analyzed all reported errors since the routine use of IMRT in our department, from January 2004 to July 2009. Fisher's exact test was used to determine the association between treatment technique (IMRT vs. 3D/conventional) and specific error types. Effect estimates were computed using logistic regression. Results: There were 155 errors in RT delivery among 241,546 fractions (0.06%), and none were clinically significant. IMRT was commonly associated with errors in machine parameters (nine of 19 errors) and data entry and interpretation (six of 19 errors). IMRT was associated with a lower rate of reported errors compared with 3D/conventional RT (0.03% vs. 0.07%, p = 0.001) and specifically fewer accessory errors (odds ratio, 0.11; 95% confidence interval, 0.01-0.78) and setup errors (odds ratio, 0.24; 95% confidence interval, 0.08-0.79). Conclusions: The rate of errors in RT delivery is low. The types of errors differ significantly between IMRT and 3D/conventional RT, suggesting that QA processes must be uniquely adapted for each technique. There

  5. Review of Air Exchange Rate Models for Air Pollution Exposure Assessments

    EPA Science Inventory

    A critical aspect of air pollution exposure assessments is estimation of the air exchange rate (AER) for various buildings, where people spend their time. The AER, which is rate the exchange of indoor air with outdoor air, is an important determinant for entry of outdoor air pol...

  6. Distributed rate allocation for multi-flow video delivery

    NASA Astrophysics Data System (ADS)

    Chakareski, Jacob; Argyriou, Antonios

    2009-01-01

    We consider rate-distortion (RD) optimized multi-flow video delivery in unstructured overlay networks. We show that this problem can be studied as a distributed rate allocation. To solve the problem over the participating peers in the overlay, we apply classical decomposition techniques such that the network-wide utility of video distortion is minimized. Media packets are assumed to be piggy-backed with RD preambles that contain information regarding their impact on decoder video distortion and their size. This allows for converting the calculated optimal rate allocation at every node into simple forwarding or dropping actions. Furthermore, the proposed distributed media streaming framework employs a network inference algorithm for minimizing the flow of duplicate packets over the network and utilizing thus more efficiently the available resources. Our simulation results indicate that significant quality benefits can be achieved when the precise RD characteristics of a media presentation are taken into account.

  7. Air velocity distributions inside tree canopies from a variable-rate air-assisted sprayer

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A variable-rate, air assisted, five-port sprayer had been in development to achieve variable discharge rates of both liquid and air. To verify the variable air rate capability by changing the fan inlet diameter of the sprayer, air jet velocities impeded by plant canopies were measured at various loc...

  8. Light dose versus rate of delivery: implications for macroalgal productivity.

    PubMed

    Desmond, Matthew J; Pritchard, Daniel W; Hepburn, Christopher D

    2017-04-07

    The role of how light is delivered over time is an area of macroalgal photosynthesis that has been overlooked but may play a significant role in controlling rates of productivity and the structure and persistence of communities. Here we present data that quantify the relative influence of total quantum dose and delivery rate on the photosynthetic productivity of five ecologically important Phaeophyceae species from southern New Zealand. Results suggested that greater net oxygen production occurs when light is delivered at a lower photon flux density (PFD) over a longer period compared to a greater PFD over a shorter period, given the same total dose. This was due to greater efficiency (α) at a lower PFD which, for some species, meant a compensatory effect can occur. This resulted in equal or greater productivity even when the total quantum dose of the lower PFD was significantly reduced. It was also shown that light limitation at Huriawa Peninsula, where macroaglae were sourced, may be restricting the acclimation potential of species at greater depths, and that even at shallow depth periods of significant light limitation are likely to occur. This research is of particular interest as the variability of light delivery to coastal reef systems increases as a result of anthropogenic disturbances, and as the value of in situ community primary productivity estimates is recognised.

  9. 37 CFR 255.6 - Royalty rate for incidental digital phonorecord deliveries.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... digital phonorecord deliveries. 255.6 Section 255.6 Patents, Trademarks, and Copyrights U.S. COPYRIGHT... for incidental digital phonorecord deliveries. The royalty rate for digital phonorecord deliveries... constitutes a digital phonorecord delivery, as specified in 17 U.S.C. 115(c)(3)(C) and (D), is deferred...

  10. Rate-limiting hydrodynamic resistance for controlled reagent delivery for laboratory solution preparation.

    PubMed

    Oruganti, Prasad; Gratzl, Miklós

    2007-03-15

    The need for precise delivery of minute quantities of substances for solution preparation and other applications is well-known in research, clinical, industrial, and environmental settings. Currently available techniques for solution preparation in the laboratory include traditional transfer pipettes, micropipettes based on air displacement, and motorized devices using some form of a piston system. These techniques control the amount delivered by controlling the delivered volume. In this work we test the practicality of the concept of using a constant rate-limiting hydrodynamic resistance to achieve controlled reagent flow for solution preparation. The delivered amount is determined in this approach by time, pressure, flow resistance, or a combination of these. Good results are achieved comparable to conventional techniques without the use of fine mechanical instrumentation. This approach holds promise as an alternative to current methods of solution preparation and reagent delivery for routine laboratory use.

  11. Air Leakage Rates in Typical Air Barrier Assemblies

    SciTech Connect

    Hun, Diana E.; Atchley, Jerald Allen; Childs, Phillip W.

    2016-11-01

    Estimates for 2010 indicate that infiltration in residential buildings was responsible for 2.85 quads of energy (DOE 2014), which is about 3% of the total energy consumed in the US. One of the mechanisms being implemented to reduce this energy penalty is the use of air barriers as part of the building envelope. These technologies decrease airflow through major leakage sites such as oriented strand board (OSB) joints, and gaps around penetrations (e.g., windows, doors, pipes, electrical outlets) as indicated by Hun et al. (2014). However, most air barrier materials do not properly address leakage spots such as wall-to-roof joints and wall-to-foundation joints because these are difficult to seal, and because air barrier manufacturers usually do not provide adequate instructions for these locations. The present study focuses on characterizing typical air leakage sites in wall assemblies with air barrier materials.

  12. Air Vehicle Technology Integration Program (AVTIP). Delivery Order 0054: Opportune Landing Site (OLS) Critical Experiment

    DTIC Science & Technology

    2008-04-01

    AFRL-RB-WP-TR-2009-3118 AIR VEHICLE TECHNOLOGY INTEGRATION PROGRAM (AVTIP) Delivery Order 0054: Opportune Landing Site (OLS) Critical...VEHICLE TECHNOLOGY INTEGRATION PROGRAM (AVTIP) Delivery Order 0054: Opportune Landing Site (OLS) Critical Experiment 5a. CONTRACT NUMBER F33615-00

  13. 37 CFR 255.6 - Royalty rate for incidental digital phonorecord deliveries.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... digital phonorecord deliveries. 255.6 Section 255.6 Patents, Trademarks, and Copyrights COPYRIGHT OFFICE... digital phonorecord deliveries. The royalty rate for digital phonorecord deliveries where the reproduction or distribution of a phonorecord is incidental to the transmission which constitutes a...

  14. 37 CFR 255.6 - Royalty rate for incidental digital phonorecord deliveries.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... digital phonorecord deliveries. 255.6 Section 255.6 Patents, Trademarks, and Copyrights COPYRIGHT OFFICE... digital phonorecord deliveries. The royalty rate for digital phonorecord deliveries where the reproduction or distribution of a phonorecord is incidental to the transmission which constitutes a...

  15. 37 CFR 255.6 - Royalty rate for incidental digital phonorecord deliveries.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... digital phonorecord deliveries. 255.6 Section 255.6 Patents, Trademarks, and Copyrights COPYRIGHT OFFICE... digital phonorecord deliveries. The royalty rate for digital phonorecord deliveries where the reproduction or distribution of a phonorecord is incidental to the transmission which constitutes a...

  16. 37 CFR 255.5 - Royalty rate for digital phonorecord deliveries in general.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 37 Patents, Trademarks, and Copyrights 1 2014-07-01 2014-07-01 false Royalty rate for digital... for digital phonorecord deliveries in general. (a) For every digital phonorecord delivery made on or... amount is larger. (b) For every digital phonorecord delivery made on or after January 1, 1998, except...

  17. 37 CFR 255.6 - Royalty rate for incidental digital phonorecord deliveries.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... digital phonorecord deliveries. 255.6 Section 255.6 Patents, Trademarks, and Copyrights COPYRIGHT OFFICE... digital phonorecord deliveries. The royalty rate for digital phonorecord deliveries where the reproduction or distribution of a phonorecord is incidental to the transmission which constitutes a...

  18. Air velocity distributions from a variable-rate air-assisted sprayer for tree applications

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A capability that implements tree structure to control liquid and air flow rates is the preferential design in the development of variable-rate orchard and nursery sprayers. Air jet velocity distributions from an air assisted, five-port sprayer which was under the development to achieve variable-rat...

  19. Dynamic Line Rating Oncor Electric Delivery Smart Grid Program

    SciTech Connect

    Johnson, Justin; Smith, Cale; Young, Mike; Donohoo, Ken; Owen, Ross; Clark, Eddit; Espejo, Raul; Aivaliotis, Sandy; Stelmak, Ron; Mohr, Ron; Barba, Cristian; Gonzalez, Guillermo; Malkin, Stuart; Dimitrova, Vessela; Ragsdale, Gary; Mitchem, Sean; Jeirath, Nakul; Loomis, Joe; Trevino, Gerardo; Syracuse, Steve; Hurst, Neil; Mereness, Matt; Johnson, Chad; Bivens, Carrie

    2013-05-04

    Electric transmission lines are the lifeline of the electric utility industry, delivering its product from source to consumer. This critical infrastructure is often constrained such that there is inadequate capacity on existing transmission lines to efficiently deliver the power to meet demand in certain areas or to transport energy from high-generation areas to high-consumption regions. When this happens, the cost of the energy rises; more costly sources of power are used to meet the demand or the system operates less reliably. These economic impacts are known as congestion, and they can amount to substantial dollars for any time frame of reference: hour, day or year. There are several solutions to the transmission constraint problem, including: construction of new generation, construction of new transmission facilities, rebuilding and reconductoring of existing transmission assets, and Dynamic Line Rating (DLR). All of these options except DLR are capital intensive, have long lead times and often experience strong public and regulatory opposition. The Smart Grid Demonstration Program (SGDP) project co-funded by the Department of Energy (DOE) and Oncor Electric Delivery Company developed and deployed the most extensive and advanced DLR installation to demonstrate that DLR technology is capable of resolving many transmission capacity constraint problems with a system that is reliable, safe and very cost competitive. The SGDP DLR deployment is the first application of DLR technology to feed transmission line real-time dynamic ratings directly into the system operation’s State Estimator and load dispatch program, which optimizes the matching of generation with load demand on a security, reliability and economic basis. The integrated Dynamic Line Rating (iDLR)1 collects transmission line parameters at remote locations on the lines, calculates the real-time line rating based on the equivalent conductor temperature, ambient temperature and influence of wind and solar

  20. Air Vehicle Technology Integration Program (AVTIP). Delivery Order 0004: Advanced Sol-Gel Adhesion Processes

    DTIC Science & Technology

    2002-04-01

    AFRL-ML-WP-TR-2003-4173 AIR VEHICLE TECHNOLOGY INTEGRATION PROGRAM (AVTIP) Delivery Order 0004: Advanced Sol-Gel Adhesion Processes Kay Y...2001 – 03/31/2002 5a. CONTRACT NUMBER F33615-00-D-3052 5b. GRANT NUMBER 4. TITLE AND SUBTITLE AIR VEHICLE TECHNOLOGY INTEGRATION PROGRAM

  1. 37 CFR 255.5 - Royalty rate for digital phonorecord deliveries in general.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 37 Patents, Trademarks, and Copyrights 1 2010-07-01 2010-07-01 false Royalty rate for digital... UNDER COMPULSORY LICENSE FOR MAKING AND DISTRIBUTING PHONORECORDS § 255.5 Royalty rate for digital phonorecord deliveries in general. (a) For every digital phonorecord delivery made on or before December...

  2. 37 CFR 255.5 - Royalty rate for digital phonorecord deliveries in general.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 37 Patents, Trademarks, and Copyrights 1 2013-07-01 2013-07-01 false Royalty rate for digital... UNDER COMPULSORY LICENSE FOR MAKING AND DISTRIBUTING PHONORECORDS § 255.5 Royalty rate for digital phonorecord deliveries in general. (a) For every digital phonorecord delivery made on or before December...

  3. 37 CFR 255.5 - Royalty rate for digital phonorecord deliveries in general.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 37 Patents, Trademarks, and Copyrights 1 2011-07-01 2011-07-01 false Royalty rate for digital... UNDER COMPULSORY LICENSE FOR MAKING AND DISTRIBUTING PHONORECORDS § 255.5 Royalty rate for digital phonorecord deliveries in general. (a) For every digital phonorecord delivery made on or before December...

  4. 37 CFR 255.5 - Royalty rate for digital phonorecord deliveries in general.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 37 Patents, Trademarks, and Copyrights 1 2012-07-01 2012-07-01 false Royalty rate for digital... UNDER COMPULSORY LICENSE FOR MAKING AND DISTRIBUTING PHONORECORDS § 255.5 Royalty rate for digital phonorecord deliveries in general. (a) For every digital phonorecord delivery made on or before December...

  5. Forecasting Foreign Currency Exchange Rates for Air Force Budgeting

    DTIC Science & Technology

    2015-03-26

    Department of Systems Engineering and Management Graduate School of Engineering and Management Air Force Institute of Technology Air University Air...this thesis: the Federal Reserve Foreign Exchange Rate – H.10, the Global Insight forecasts, the Chicago Mercantile Exchange (CME) as taken through...foreign currency units per U.S. dollar for each day of the previous week (Board of Governors of the Federal Reserve System , 2015). Table 3 is a

  6. Position paper -- Tank ventilation system design air flow rates

    SciTech Connect

    Goolsby, G.K.

    1995-01-04

    The purpose of this paper is to document a project position on required ventilation system design air flow rates for the waste storage tanks currently being designed by project W-236A, the Multi-Function Waste Tank Facility (MWTF). The Title 1 design primary tank heat removal system consists of two systems: a primary tank vapor space ventilation system; and an annulus ventilation system. At the conclusion of Title 1 design, air flow rates for the primary and annulus ventilation systems were 960 scfm and 4,400 scfm, respectively, per tank. These design flow rates were capable of removing 1,250,000 Btu/hr from each tank. However, recently completed and ongoing studies have resulted in a design change to reduce the extreme case heat load to 700,000 Btu/hr. This revision of the extreme case heat load, coupled with results of scale model evaporative testing performed by WHC Thermal Hydraulics, allow for a reduction of the design air flow rates for both primary and annulus ventilation systems. Based on the preceding discussion, ICF Kaiser Hanford Co. concludes that the design should incorporate the following design air flow rates: Primary ventilation system--500 scfm maximum and Annulus ventilation system--1,100 scfm maximum. In addition, the minimum air flow rates in the primary and annulus ventilation systems will be investigated during Title 2 design. The results of the Title 2 investigation will determine the range of available temperature control using variable air flows to both ventilation systems.

  7. Honeybee flight metabolic rate: does it depend upon air temperature?

    PubMed

    Woods, William A; Heinrich, Bernd; Stevenson, Robert D

    2005-03-01

    Differing conclusions have been reached as to how or whether varying heat production has a thermoregulatory function in flying honeybees Apis mellifera. We investigated the effects of air temperature on flight metabolic rate, water loss, wingbeat frequency, body segment temperatures and behavior of honeybees flying in transparent containment outdoors. For periods of voluntary, uninterrupted, self-sustaining flight, metabolic rate was independent of air temperature between 19 and 37 degrees C. Thorax temperatures (T(th)) were very stable, with a slope of thorax temperature on air temperature of 0.18. Evaporative heat loss increased from 51 mW g(-1) at 25 degrees C to 158 mW g(-1) at 37 degrees C and appeared to account for head and abdomen temperature excess falling sharply over the same air temperature range. As air temperature increased from 19 to 37 degrees C, wingbeat frequency showed a slight but significant increase, and metabolic expenditure per wingbeat showed a corresponding slight but significant decrease. Bees spent an average of 52% of the measurement period in flight, with 19 of 78 bees sustaining uninterrupted voluntary flight for periods of >1 min. The fraction of time spent flying declined as air temperature increased. As the fraction of time spent flying decreased, the slope of metabolic rate on air temperature became more steeply negative, and was significant for bees flying less than 80% of the time. In a separate experiment, there was a significant inverse relationship of metabolic rate and air temperature for bees requiring frequent or constant agitation to remain airborne, but no dependence for bees that flew with little or no agitation; bees were less likely to require agitation during outdoor than indoor measurements. A recent hypothesis explaining differences between studies in the slope of flight metabolic rate on air temperature in terms of differences in metabolic capacity and thorax temperature is supported for honeybees in voluntary

  8. Maternal and neonatal morbidity and mortality rate in caesarean section and vaginal delivery

    PubMed Central

    Ghahiri, Ataollah; Khosravi, Mehrnoush

    2015-01-01

    Background: The cesarean section is one of the most common procedures to prevent health-threatening risks to the mother and infant. Increasing rate of cesarean section attracted the attention of professionals and the overall objective of this study was to determine the frequency of maternal and neonatal morbidity and mortality rates in the two methods of delivery. Materials and Methods: In a comparative cohort study, 300 cases undergoing caesarean section and 300 cases with vaginal delivery were selected in two main hospitals of Isfahan, Iran during 2013 and 2014. Demographic characteristics and factors related to mortality and morbidity of mothers and infants were studied. Mothers were also recruited 6 weeks after delivery to ask for complications. Mothers and infants mortality and morbidity were studied and analyzed by SPSS 22 software. Results: Follow-up of deliveries up to 1-month after delivery suggested 2 cases of infant death (7%) in vaginal delivery group, while no case of infant death was reported in cesarean delivery group (P = 0.5). Incidence of fever was observed in first 10 days after delivery in 7 cases in the vaginal delivery group and 11 cases in the cesarean delivery group (2.3% vs. 3.7%, P = 0.4). Conclusion: Despite all the benefits of vaginal delivery compared with cesarean section, in many cases, especially in emergency cesarean section delivery can substantially reduce the maternal and neonatal mortality and morbidity. It is recommended to assess the complications of each method in all pregnant women about to give birth, and then decide on the method of delivery. PMID:26605232

  9. Air Vehicle Technology Integration Program (AVTIP). Delivery Order 0020: Prediction of Manufacturing Tolerances for Laminar Flow, Task 6

    DTIC Science & Technology

    2006-09-01

    AFRL-VA-WP-TR-2007-3086 AIR VEHICLE TECHNOLOGY INTEGRATION PROGRAM (AVTIP) Delivery Order 0020: Prediction of Manufacturing Tolerances for...NUMBER F33615-00-D-3054-0020 5b. GRANT NUMBER 4. TITLE AND SUBTITLE AIR VEHICLE TECHNOLOGY INTEGRATION PROGRAM (AVTIP) Delivery Order 0020

  10. Design and Implementation of Automatic Air Flow Rate Control System

    NASA Astrophysics Data System (ADS)

    Akbar, A.; Saputra, C.; Munir, M. M.; Khairurrijal

    2016-08-01

    Venturimeter is an apparatus that can be used to measure the air flow rate. In this experiment we designed a venturimeter which equipped with a valve that is used to control the air flow rate. The difference of pressure between the cross sections was measured with the differential pressure sensor GA 100-015WD which can calculate the difference of pressures from 0 to 3737.33 Pa. A 42M048C Z36 stepper motor was used to control the valve. The precision of this motor rotation is about 0.15 °. A Graphical User Interface (GUI) was developed to monitor and set the value of flow rate then an 8-bit microcontroller was used to process the control system In this experiment- the venturimeter has been examined to get the optimal parameter of controller. The results show that the controller can set the stable output air flow rate.

  11. Flying-qualities criteria for wings-level-turn maneuvering during an air-to-ground weapon delivery task

    NASA Technical Reports Server (NTRS)

    Sammonds, R. I.; Bunnell, J. W.

    1981-01-01

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

  12. Flying-qualities criteria for wings-level-turn maneuvering during an air-to-ground weapon delivery task

    NASA Technical Reports Server (NTRS)

    Sammonds, R. I.; Bunnell, J. W., Jr.

    1980-01-01

    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 on the basis of equivalent time constant of the initial response. Ranges of this time constant, as well as digital-system transport delays and lateral-acceleration control authorities that encompassed Level I through Level III handling qualities, were determined.

  13. Measuring Outdoor Air Intake Rates into Existing Building

    SciTech Connect

    Fisk, William; Sullivan, Douglas; Cohen, Sebastian; Han, Hwataik

    2009-04-16

    Practical and accurate technologies are needed for continuously measuring and controlling outdoor air (OA) intake rates in commercial building heating, ventilating, and air conditioning (HVAC) systems. This project evaluated two new measurement approaches. Laboratory experiments determined that OA flow rates were measurable with errors generally less than 10 percent using electronic air velocity probes installed between OA intake louver blades or at the outlet face of louvers. High accuracy was maintained with OA flow rates as low as 15 percent of the maximum for the louvers. Thus, with this measurement approach HVAC systems do not need separate OA intakes for minimum OA supply. System calibration parameters are required for each unique combination of louver type and velocity sensor location but calibrations are not necessary for each system installation. The research also determined that the accuracy of measuring OA flow rates with velocity probes located in the duct downstream of the intake louver was not improved by installing honeycomb airflow straighteners upstream of the probes. Errors varied with type of upstream louver, were as high as 100 percent, and were often greater than 25 percent. In conclusion, use of electronic air velocity probes between the blades of OA intake louvers or at the outlet face of louvers is a highly promising means of accurately measuring rates of OA flow into HVAC systems. The use of electronic velocity probes downstream of airflow straighteners is less promising, at least with the relatively small OA HVAC inlet systems employed in this research.

  14. Evaluation of an extended duct air delivery system for spaces conditioned by rooftop units

    NASA Astrophysics Data System (ADS)

    Kennett, Ryan

    Traditional air delivery to high-bay buildings involves ceiling level supply and return ducts that create an almost-uniform temperature in the space. Problems with this system include potential recirculation of supply air and higher-than-necessary return air temperatures. A new air delivery strategy was investigated that involves changing the height of conventional supply and return ducts to have control over thermal stratification in the space. A full-scale experiment using ten vertical temperature profiles was conducted in a manufacturing facility over one year. The experimental data was utilized to validated CFD and EnergyPlus models. CFD simulation results show that supplying air directly to the occupied zone increases stratification while holding thermal comfort constant during the cooling operation. The building energy simulation identified how return air temperature offset, set point offset, and stratification influence the building's energy consumption. A utility bill analysis for cooling shows 28.8% HVAC energy savings while the building energy simulation shows 19.3-37.4% HVAC energy savings.

  15. High Lapse Rates in AIRS Retrieved Temperatures in Cold Air Outbreaks

    NASA Technical Reports Server (NTRS)

    Fetzer, Eric J.; Kahn, Brian; Olsen, Edward T.; Fishbein, Evan

    2004-01-01

    The Atmospheric Infrared Sounder (AIRS) experiment, on NASA's Aqua spacecraft, uses a combination of infrared and microwave observations to retrieve cloud and surface properties, plus temperature and water vapor profiles comparable to radiosondes throughout the troposphere, for cloud cover up to 70%. The high spectral resolution of AIRS provides sensitivity to important information about the near-surface atmosphere and underlying surface. A preliminary analysis of AIRS temperature retrievals taken during January 2003 reveals extensive areas of superadiabatic lapse rates in the lowest kilometer of the atmosphere. These areas are found predominantly east of North America over the Gulf Stream, and, off East Asia over the Kuroshio Current. Accompanying the high lapse rates are low air temperatures, large sea-air temperature differences, and low relative humidities. Imagery from a Visible / Near Infrared instrument on the AIRS experiment shows accompanying clouds. These lines of evidence all point to shallow convection in the bottom layer of a cold air mass overlying warm water, with overturning driven by heat flow from ocean to atmosphere. An examination of operational radiosondes at six coastal stations in Japan shows AIRS to be oversensitive to lower tropospheric lapse rates due to systematically warm near-surface air temperatures. The bias in near-surface air temperature is seen to be independent of sea surface temperature, however. AIRS is therefore sensitive to air-sea temperature difference, but with a warm atmospheric bias. A regression fit to radiosondes is used to correct AIRS near-surface retrieved temperatures, and thereby obtain an estimate of the true atmosphere-ocean thermal contrast in five subtropical regions across the north Pacific. Moving eastward, we show a systematic shift in this air-sea temperature differences toward more isothermal conditions. These results, while preliminary, have implications for our understanding of heat flow from ocean to

  16. [Delivery room resuscitation with room air and oxygen in newborns. State of art, recommendations].

    PubMed

    Lauterbach, Ryszard; Musialik-Swietlińska, Ewa; Swietliński, Janusz; Pawlik, Dorota; Bober, Klaudiusz

    2008-01-01

    The authors present and discuss the current data, concerning delivery room resuscitation with oxygen and room air in neonates. On the ground of the results obtained from literature and the Polish National Survey on Paediatric and Neonatal Intensive Care, 2007/2008 issue, the authors give the following proposals regarding optimal oxygen treatment: 1. there is a need for optimizing tissue oxygenation in order to prevent injury caused by radical oxygen species; 2. newborn resuscitation should be monitored by measuring the haemoglobin saturation - the values above 90%, found in resuscitated newborn within the first minutes of life may be dangerous and cause tissue injury; 3. starting the resuscitation with oxygen concentration lower than 40% and adjusting it according to the effects of the procedure - the less mature infant the lower oxygen concentration at the beginning of resuscitation; 4. heart rate >100/min and SatO2Hb between 70-80% within the first minutes of life should not be an indication for increasing oxygen concentration.

  17. Impacts of Changes of Indoor Air Pressure and Air Exchange Rate in Vapor Intrusion Scenarios.

    PubMed

    Shen, Rui; Suuberg, Eric M

    2016-02-01

    There has, in recent years, been increasing interest in understanding the transport processes of relevance in vapor intrusion of volatile organic compounds (VOCs) into buildings on contaminated sites. These studies have included fate and transport modeling. Most such models have simplified the prediction of indoor air contaminant vapor concentrations by employing a steady state assumption, which often results in difficulties in reconciling these results with field measurements. This paper focuses on two major factors that may be subject to significant transients in vapor intrusion situations, including the indoor air pressure and the air exchange rate in the subject building. A three-dimensional finite element model was employed with consideration of daily and seasonal variations in these factors. From the results, the variations of indoor air pressure and air exchange rate are seen to contribute to significant variations in indoor air contaminant vapor concentrations. Depending upon the assumptions regarding the variations in these parameters, the results are only sometimes consistent with the reports of several orders of magnitude in indoor air concentration variations from field studies. The results point to the need to examine more carefully the interplay of these factors in order to quantitatively understand the variations in potential indoor air exposures.

  18. Impacts of Changes of Indoor Air Pressure and Air Exchange Rate in Vapor Intrusion Scenarios

    PubMed Central

    Shen, Rui; Suuberg, Eric M.

    2016-01-01

    There has, in recent years, been increasing interest in understanding the transport processes of relevance in vapor intrusion of volatile organic compounds (VOCs) into buildings on contaminated sites. These studies have included fate and transport modeling. Most such models have simplified the prediction of indoor air contaminant vapor concentrations by employing a steady state assumption, which often results in difficulties in reconciling these results with field measurements. This paper focuses on two major factors that may be subject to significant transients in vapor intrusion situations, including the indoor air pressure and the air exchange rate in the subject building. A three-dimensional finite element model was employed with consideration of daily and seasonal variations in these factors. From the results, the variations of indoor air pressure and air exchange rate are seen to contribute to significant variations in indoor air contaminant vapor concentrations. Depending upon the assumptions regarding the variations in these parameters, the results are only sometimes consistent with the reports of several orders of magnitude in indoor air concentration variations from field studies. The results point to the need to examine more carefully the interplay of these factors in order to quantitatively understand the variations in potential indoor air exposures. PMID:28090133

  19. A Method for Rating Computer-Based Career Information Delivery Systems.

    ERIC Educational Resources Information Center

    Bloch, Deborah Perlmutter; Kinnison, Joyce Ford

    1989-01-01

    Developed a three-part rating system for computer-based career information delivery systems in the areas of comprehensiveness, accuracy, and effectiveness. Used system to rate five popular computer-based systems (C-LECT, CHOICES, CIS, DISCOVER, and GIS). Four systems were evaluated as being very similar, with CIS receiving highest scores.…

  20. Yaw rate control of an air bearing vehicle

    NASA Technical Reports Server (NTRS)

    Walcott, Bruce L.

    1989-01-01

    The results of a 6 week project which focused on the problem of controlling the yaw (rotational) rate the air bearing vehicle used on NASA's flat floor facility are summarized. Contained within is a listing of the equipment available for task completion and an evaluation of the suitability of this equipment. The identification (modeling) process of the air bearing vehicle is detailed as well as the subsequent closed-loop control strategy. The effectiveness of the solution is discussed and further recommendations are included.

  1. Vented spikes improve delivery from intravenous bags with no air headspace.

    PubMed

    Galush, William J; Horst, Travis A

    2015-07-01

    Flexible plastic bags are the container of choice for most intravenous (i.v.) infusions. Under certain circumstances, however, the air-liquid interface present in these i.v. bags can lead to physical instability of protein biopharmaceuticals, resulting in product aggregation. In principle, the air headspace present in the bags can be removed to increase drug stability, but experiments described here show that this can result in incomplete draining of solution from the bag using gravity delivery, or generation of negative pressure in the bag when an infusion pump is used. It is expected that these issues could lead to incomplete delivery of medication to patients or pump-related problems, respectively. However, here it is shown that contrary to the standard pharmacy practice of using nonvented spikes with i.v. bags, the use of vented spikes with i.v. bags that lack air headspace allows complete delivery of the dose solution without impacting the physical stability of a protein-based drug.

  2. Versatile radar measurement of the electron loss rate in air

    NASA Astrophysics Data System (ADS)

    Dogariu, Arthur; Shneider, Mikhail N.; Miles, Richard B.

    2013-11-01

    We present an experimental method that makes possible in-situ measurements of the electron loss rate in arbitrary gas mixtures. A weakly ionized plasma is induced via resonant multiphoton ionization of trace amounts of nitric oxide seeded into the gas, and homodyne microwave scattering detection is used to study the dynamics of the electron loss mechanisms. Using this approach, the attachment rate for electrons to molecular oxygen in room temperature, atmospheric pressure air is determined. The measured 0.76 × 108 s-1 attachment rate is in very good agreement with predictions based on literature data.

  3. Versatile radar measurement of the electron loss rate in air

    SciTech Connect

    Dogariu, Arthur; Shneider, Mikhail N.; Miles, Richard B.

    2013-11-25

    We present an experimental method that makes possible in-situ measurements of the electron loss rate in arbitrary gas mixtures. A weakly ionized plasma is induced via resonant multiphoton ionization of trace amounts of nitric oxide seeded into the gas, and homodyne microwave scattering detection is used to study the dynamics of the electron loss mechanisms. Using this approach, the attachment rate for electrons to molecular oxygen in room temperature, atmospheric pressure air is determined. The measured 0.76 × 10{sup 8} s{sup −1} attachment rate is in very good agreement with predictions based on literature data.

  4. Air traffic control surveillance accuracy and update rate study

    NASA Technical Reports Server (NTRS)

    Craigie, J. H.; Morrison, D. D.; Zipper, I.

    1973-01-01

    The results of an air traffic control surveillance accuracy and update rate study are presented. The objective of the study was to establish quantitative relationships between the surveillance accuracies, update rates, and the communication load associated with the tactical control of aircraft for conflict resolution. The relationships are established for typical types of aircraft, phases of flight, and types of airspace. Specific cases are analyzed to determine the surveillance accuracies and update rates required to prevent two aircraft from approaching each other too closely.

  5. A review of air exchange rate models for air pollution exposure assessments.

    PubMed

    Breen, Michael S; Schultz, Bradley D; Sohn, Michael D; Long, Thomas; Langstaff, John; Williams, Ronald; Isaacs, Kristin; Meng, Qing Yu; Stallings, Casson; Smith, Luther

    2014-11-01

    A critical aspect of air pollution exposure assessments is estimation of the air exchange rate (AER) for various buildings where people spend their time. The AER, which is the rate of exchange of indoor air with outdoor air, is an important determinant for entry of outdoor air pollutants and for removal of indoor-emitted air pollutants. This paper presents an overview and critical analysis of the scientific literature on empirical and physically based AER models for residential and commercial buildings; the models highlighted here are feasible for exposure assessments as extensive inputs are not required. Models are included for the three types of airflows that can occur across building envelopes: leakage, natural ventilation, and mechanical ventilation. Guidance is provided to select the preferable AER model based on available data, desired temporal resolution, types of airflows, and types of buildings included in the exposure assessment. For exposure assessments with some limited building leakage or AER measurements, strategies are described to reduce AER model uncertainty. This review will facilitate the selection of AER models in support of air pollution exposure assessments.

  6. Developing a Commercial Air Ultrasonic Ceramic Transducer to Transdermal Insulin Delivery

    PubMed Central

    Jabbari, Nasrollah; Asghari, Mohammad Hossein; Ahmadian, Hassan; Mikaili, Peyman

    2015-01-01

    The application of low-frequency ultrasound for transdermal delivery of insulin is of particular public interest due to the increasing problem of diabetes. The purpose of this research was to develop an air ultrasonic ceramic transducer for transdermal insulin delivery and evaluate the possibility of applying a new portable and low-cost device for transdermal insulin delivery. Twenty-four rats were divided into four groups with six rats in each group: one control group and three experimental groups. Control group (C) did not receive any ultrasound exposure or insulin (untreated group). The second group (T1) was treated with subcutaneous insulin (Humulin® R, rDNA U-100, Eli Lilly and Co., Indianapolis, IN) injection (0.25 U/Kg). The third group (T2) topically received insulin, and the fourth group (T3) received insulin with ultrasound waves. All the rats were anesthetized by intraperitoneal injection of ketamin hydrochloride and xylazine hydrochloride. Blood samples were collected after anesthesia to obtain a baseline glucose level. Additional blood samples were taken every 15 min in the whole 90 min experiment. In order for comparison the changes in blood glucose levels” to “ In order to compare the changes in blood glucose levels. The statistical multiple comparison (two-sided Tukey) test showed a significant difference between transdermal insulin delivery group (T2) and subcutaneous insulin injection group (T1) during 90 min experiment (P = 0.018). In addition, the difference between transdermal insulin delivery group (T2) and ultrasonic transdermal insulin delivery group (T3) was significant (P = 0.001). Results of this study demonstrated that the produced low-frequency ultrasound from this device enhanced the transdermal delivery of insulin across hairless rat skin. PMID:26120571

  7. Developing a Commercial Air Ultrasonic Ceramic Transducer to Transdermal Insulin Delivery.

    PubMed

    Jabbari, Nasrollah; Asghari, Mohammad Hossein; Ahmadian, Hassan; Mikaili, Peyman

    2015-01-01

    The application of low-frequency ultrasound for transdermal delivery of insulin is of particular public interest due to the increasing problem of diabetes. The purpose of this research was to develop an air ultrasonic ceramic transducer for transdermal insulin delivery and evaluate the possibility of applying a new portable and low-cost device for transdermal insulin delivery. Twenty-four rats were divided into four groups with six rats in each group: one control group and three experimental groups. Control group (C) did not receive any ultrasound exposure or insulin (untreated group). The second group (T1) was treated with subcutaneous insulin (Humulin(®) R, rDNA U-100, Eli Lilly and Co., Indianapolis, IN) injection (0.25 U/Kg). The third group (T2) topically received insulin, and the fourth group (T3) received insulin with ultrasound waves. All the rats were anesthetized by intraperitoneal injection of ketamin hydrochloride and xylazine hydrochloride. Blood samples were collected after anesthesia to obtain a baseline glucose level. Additional blood samples were taken every 15 min in the whole 90 min experiment. In order for comparison the changes in blood glucose levels" to " In order to compare the changes in blood glucose levels. The statistical multiple comparison (two-sided Tukey) test showed a significant difference between transdermal insulin delivery group (T2) and subcutaneous insulin injection group (T1) during 90 min experiment (P = 0.018). In addition, the difference between transdermal insulin delivery group (T2) and ultrasonic transdermal insulin delivery group (T3) was significant (P = 0.001). Results of this study demonstrated that the produced low-frequency ultrasound from this device enhanced the transdermal delivery of insulin across hairless rat skin.

  8. Air Controlman 3 and 2: Naval Rate Training Manual and Nonresident Career Course.

    ERIC Educational Resources Information Center

    Naval Education and Training Command, Pensacola, FL.

    The Rate Training Manual is one of a series of training manuals prepared for enlisted personnel of the Navy and Naval Reserve studying for advancement in the Air Controlman (AC) rating to Air Controlman Third and Second Class. Chapter 1 discusses air controlman qualifications, the enlisted rating structure, the Air Controlman rating, references…

  9. Zero-Spring-Rate Mechanism/Air Suspension Cart

    NASA Technical Reports Server (NTRS)

    Woodard, Stanley E.; Cooley, Victor M.

    1991-01-01

    Compact mechanism suspends articulating flexible structures with minimal constraints. Zero-spring-rate mechanism (ZSRM) air suspension cart used to suspend flexible, "mass-critical" articles like lightweight spacecraft undergoing such large motions as slewing, translation, and telescoping/retraction. Suspends flexible article undergoing large rigid-body motion concurrent with vibratory motion, with minimal interaction between suspended article and suspending hardware. Adaptive to active control, which reduces undesirable effects caused by friction, nonlinearity, and mass coupling. Practical for most suspension applications.

  10. Air exchange rates in new energy-efficient manufactured housing

    SciTech Connect

    Hadley, D.; Bailey, S.

    1990-10-01

    During the 1989--1990 heating season, Pacific Northwest Laboratory, for the Bonneville Power Administration, measured the ventilation characteristics of 139 newly constructed energy-efficient manufactured homes and a control sample of 35 newer manufactured homes. A standard door fan pressurization technique was used to estimate shell leakiness, and a passive perfluorocarbon tracer technique was used to estimate overall air exchange rates. A measurement of the designated whole-house exhaust system flow rate was taken as well as an occupant and structure survey. The energy-efficient manufactured homes have very low air exchange rates, significantly lower than either existing manufactured homes or site-built homes. The standard deviation of the effective leakage area for this sample of homes is small (25% to 30% of the mean), indicating that the leakiness of manufactured housing stock can be confidently characterized by the mean value. There is some indication of increased ventilation due to the energy-efficient whole-house ventilation specification, but not directly related to the operation of the whole-house system. The mechanical systems as installed and operated do not provide the intended ventilation; consequently indoor air quality could possibly be adversely impacted and moisture/condensation in the living space is a potential problem. 6 refs., 6 figs., 5 tabs.

  11. Experimental study on the delivery rate and recovery rate of ZrCo hydride for ITER application

    SciTech Connect

    Shim, M.; Chung, H.; Yoshida, H.; Kim, K.; Cho, S.; Lee, E.; Chang, M.

    2008-07-15

    To investigate the key design aspects of the storage and delivery system (SDS) bed in ITER, rates of a hydriding, de-hydriding and isotope effects on the H/D composition during a rapid delivery were experimentally investigated by using small tube-type reactors with different packing heights. Hydrogen recovery times for a shorter packing-height bed (20-40 mm) decreased exponentially with an increasing initial hydrogen pressure, but increased by approximately two orders of a magnitude in a longer packing-height bed (145 mm). De-hydriding rate increases exponentially with an increase in the relative heating area per unit weight of ZrCo powder and decreases in the packing-height of ZrCo hydride. Continuous isotopic compositional change inevitably occurs during the entire delivery time due to the known isotope effect in the metal-hydrogen systems. To overcome the isotope effect during a delivery from the SDS beds, an alternative operation method was suggested for the fuel supply from the SDS. (authors)

  12. Activated air produced by shielded sliding discharge plasma mediates plasmid DNA delivery to mammalian cells.

    PubMed

    Edelblute, Chelsea M; Heller, Loree C; Malik, Muhammad A; Heller, Richard

    2015-12-01

    Cold plasma is emerging as a potential method for medical applications. The current study assessed the efficacy of a novel cold plasma reactor based on shielded sliding discharge producing cathode-directed streamers generated in ambient air for the delivery of plasmid DNA. Experiments were performed with mouse melanoma cells (B16F10) and human keratinocyte cells (HaCaT) inoculated with plasmid DNA encoding luciferase. Quantitative results measured over a 72-h period displayed luciferase expression levels as high as 5-fold greater in cells exposed to plasma-activated air (PAA) than levels obtained from the inoculation of plasmid DNA alone (P < 0.05, P < 0.01). No effect on cell viability was observed. Delivery of plasmid encoding GFP to HaCaT cells seeded on polycaprolactone (PCL) scaffolds was confirmed by immunostaining. The use of cold plasma for DNA delivery is attractive as it provides a non-viral, non-invasive method where the electrode or the plasma itself never directly contacts the exposed site. The current device design provides localized DNA transfer using a novel technology. Our report suggests PAA warrants further exploration as an alternative or supplemental approach for DNA transfer.

  13. Rotational IMRT delivery using a digital linear accelerator in very high dose rate 'burst mode'

    NASA Astrophysics Data System (ADS)

    Salter, Bill J.; Sarkar, Vikren; Wang, Brian; Shukla, Himanshu; Szegedi, Martin; Rassiah-Szegedi, Prema

    2011-04-01

    Recently, there has been a resurgence of interest in arc-based IMRT, through the use of 'conventional' multileaf collimator (MLC) systems that can treat large tumor volumes in a single, or very few pass(es) of the gantry. Here we present a novel 'burst mode' modulated arc delivery approach, wherein 2000 monitor units per minute (MU min-1) high dose rate bursts of dose are facilitated by a flattening-filter-free treatment beam on a Siemens Artiste (Oncology Care Systems, Siemens Medical Solutions, Concord, CA, USA) digital linear accelerator in a non-clinical configuration. Burst mode delivery differs from continuous mode delivery, used by Elekta's VMAT (Elekta Ltd, Crawley, UK) and Varian's RapidArc (Varian Medical Systems, Palo Alto, CA, USA) implementations, in that dose is not delivered while MLC leaves are moving. Instead, dose is delivered in bursts over very short arc angles and only after an MLC segment shape has been completely formed and verified by the controller. The new system was confirmed to be capable of delivering a wide array of clinically relevant treatment plans, without machine fault or other delivery anomalies. Dosimetric accuracy of the modulated arc platform, as well as the Prowess (Prowess Inc., Concord, CA, USA) prototype treatment planning version utilized here, was quantified and confirmed, and delivery times were measured as significantly brief, even with large hypofractionated doses. The burst mode modulated arc approach evaluated here appears to represent a capable, accurate and efficient delivery approach.

  14. Rotational IMRT delivery using a digital linear accelerator in very high dose rate 'burst mode'.

    PubMed

    Salter, Bill J; Sarkar, Vikren; Wang, Brian; Shukla, Himanshu; Szegedi, Martin; Rassiah-Szegedi, Prema

    2011-04-07

    Recently, there has been a resurgence of interest in arc-based IMRT, through the use of 'conventional' multileaf collimator (MLC) systems that can treat large tumor volumes in a single, or very few pass(es) of the gantry. Here we present a novel 'burst mode' modulated arc delivery approach, wherein 2000 monitor units per minute (MU min(-1)) high dose rate bursts of dose are facilitated by a flattening-filter-free treatment beam on a Siemens Artiste (Oncology Care Systems, Siemens Medical Solutions, Concord, CA, USA) digital linear accelerator in a non-clinical configuration. Burst mode delivery differs from continuous mode delivery, used by Elekta's VMAT (Elekta Ltd, Crawley, UK) and Varian's RapidArc (Varian Medical Systems, Palo Alto, CA, USA) implementations, in that dose is not delivered while MLC leaves are moving. Instead, dose is delivered in bursts over very short arc angles and only after an MLC segment shape has been completely formed and verified by the controller. The new system was confirmed to be capable of delivering a wide array of clinically relevant treatment plans, without machine fault or other delivery anomalies. Dosimetric accuracy of the modulated arc platform, as well as the Prowess (Prowess Inc., Concord, CA, USA) prototype treatment planning version utilized here, was quantified and confirmed, and delivery times were measured as significantly brief, even with large hypofractionated doses. The burst mode modulated arc approach evaluated here appears to represent a capable, accurate and efficient delivery approach.

  15. Probabilistic estimation of residential air exchange rates for ...

    EPA Pesticide Factsheets

    Residential air exchange rates (AERs) are a key determinant in the infiltration of ambient air pollution indoors. Population-based human exposure models using probabilistic approaches to estimate personal exposure to air pollutants have relied on input distributions from AER measurements. An algorithm for probabilistically estimating AER was developed based on the Lawrence Berkley National Laboratory Infiltration model utilizing housing characteristics and meteorological data with adjustment for window opening behavior. The algorithm was evaluated by comparing modeled and measured AERs in four US cities (Los Angeles, CA; Detroit, MI; Elizabeth, NJ; and Houston, TX) inputting study-specific data. The impact on the modeled AER of using publically available housing data representative of the region for each city was also assessed. Finally, modeled AER based on region-specific inputs was compared with those estimated using literature-based distributions. While modeled AERs were similar in magnitude to the measured AER they were consistently lower for all cities except Houston. AERs estimated using region-specific inputs were lower than those using study-specific inputs due to differences in window opening probabilities. The algorithm produced more spatially and temporally variable AERs compared with literature-based distributions reflecting within- and between-city differences, helping reduce error in estimates of air pollutant exposure. Published in the Journal of

  16. Effects of Periodontal Therapy on Rate of Preterm Delivery A Randomized Controlled Trial

    PubMed Central

    Offenbacher, Steven; Beck, James D.; Jared, Heather L.; Mauriello, Sally M.; Mendoza, Luisto C.; Couper, David J.; Stewart, Dawn D.; Murtha, Amy P.; Cochran, David L.; Dudley, Donald J.; Reddy, Michael S.; Geurs, Nicolaas C.; Hauth, John C.

    2010-01-01

    OBJECTIVE To test the effects of maternal periodontal disease treatment on the incidence of preterm birth (delivery before 37 weeks of gestation). METHODS The Maternal Oral Therapy to Reduce Obstetric Risk Study was a randomized, treatment-masked, controlled clinical trial of pregnant women with periodontal disease who were receiving standard obstetric care. Participants were assigned to either a periodontal treatment arm, consisting of scaling and root planing early in the second trimester, or a delayed treatment arm that provided periodontal care after delivery. Pregnancy and maternal periodontal status were followed to delivery and neonatal outcomes until discharge. The primary outcome (gestational age less than 37 weeks) and the secondary outcome (gestational age less than 35 weeks) were analyzed using a χ2 test of equality of two proportions. RESULTS The study randomized 1,806 patients at three performance sites and completed 1,760 evaluable patients. At baseline, there were no differences comparing the treatment and control arms for any of the periodontal or obstetric measures. The rate of preterm delivery for the treatment group was 13.1% and 11.5% for the control group (P=.316). There were no significant differences when comparing women in the treatment group with those in the control group with regard to the adverse event rate or the major obstetric and neonatal outcomes. CONCLUSION Periodontal therapy did not reduce the incidence of preterm delivery. CLINICAL TRIAL REGISTRATION ClinicalTrials.gov, www.clinicaltrials.gov, NCT00097656. LEVEL OF EVIDENCE I PMID:19701034

  17. Loading Rates and Impacts of Substrate Delivery for Enhanced Anaerobic Bioremediation

    DTIC Science & Technology

    2010-01-01

    IMPROVED/ALTERNATIVE DELIVERY TECHNIQUES .............................. 20 5.5 ALTERNATE DEGRADATION PROCESSES ...contaminants subject to anaerobic degradation processes . The authors acknowledge the assistance of numerous individuals who provided site data and...reduction (redox) conditions for anaerobic degradation processes to occur. Substrate loading rates are defined as the volume, concentration, and

  18. Air core Bragg fibers for delivery of near-infrared laser radiation

    NASA Astrophysics Data System (ADS)

    Jelínek, Michal; Frank, Milan; Kubeček, Václav; Matějec, Vlastimil; Kašík, Ivan; Podrazký, Ondřej

    2014-12-01

    Optical fibers designed for high power laser radiation delivery represent important tools in medicine, solar systems, or industry. For such purposes several different types of glass optical fibers such as silica, sapphire, or chalcogenide ones as well as hollow-glass fibers, photonic crystal fibers and Bragg fibers have been investigated. Air-core Bragg fibers or photonic crystal fibers offer us the possibility of light transmission in a low dispersive material - air having a high damage threshold and small non-linear coefficient. However, preforms for drawing Bragg fibers can be fabricated by MCVD method similarly as preforms of standard silica fibers. In this paper we present fundamental characteristics of laboratory-designed and fabricated Bragg fibers with air cores intended for delivery of laser radiation at a wavelength range from 0.9 to 1.5 μm. Bragg fibers with different air core diameters of 5, 45 and 73 mm were prepared. The fiber core was surrounded by three pairs of circular Bragg layers. Each pair was composed of one layer with a high and one layer with a low refractive index with a contrast up to 0.03. Several laser sources emitting at 0.975, 1.06, and 1.55 μm were used as radiation sources. Attenuation coefficients, overall transmissions, bending losses, and spatial profiles of output beams from fibers were determined at these wavelengths. The lowest attenuation coefficient of 70 dB/km was determined for the 45 μm and 73 mm air-core fiber when radiation from a laser was launched into the fibers by using optical lenses. However, multimodal transmission has been observed in such condition. It has also been found that bending losses of such fibers are negligible for bending diameters higher than 15 mm.

  19. Flexible Wing Base Micro Aerial Vehicles: Micro Air Vehicles (MAVs) for Surveillance and Remote Sensor Delivery

    NASA Technical Reports Server (NTRS)

    Ifju, Peter

    2002-01-01

    Micro Air Vehicles (MAVs) will be developed for tracking individuals, locating terrorist threats, and delivering remote sensors, for surveillance and chemical/biological agent detection. The tasks are: (1) Develop robust MAV platform capable of carrying sensor payload. (2) Develop fully autonomous capabilities for delivery of sensors to remote and distant locations. The current capabilities and accomplishments are: (1) Operational electric (inaudible) 6-inch MAVs with novel flexible wing, providing superior aerodynamic efficiency and control. (2) Vision-based flight stability and control (from on-board cameras).

  20. Rate-programming of nano-particulate delivery systems for smart bioactive scaffolds in tissue engineering

    NASA Astrophysics Data System (ADS)

    Izadifar, Mohammad; Haddadi, Azita; Chen, Xiongbiao; Kelly, Michael E.

    2015-01-01

    Development of smart bioactive scaffolds is of importance in tissue engineering, where cell proliferation, differentiation and migration within scaffolds can be regulated by the interactions between cells and scaffold through the use of growth factors (GFs) and extra cellular matrix peptides. One challenge in this area is to spatiotemporally control the dose, sequence and profile of release of GFs so as to regulate cellular fates during tissue regeneration. This challenge would be addressed by rate-programming of nano-particulate delivery systems, where the release of GFs via polymeric nanoparticles is controlled by means of the methods of, such as externally-controlled and physicochemically/architecturally-modulated so as to mimic the profile of physiological GFs. Identifying and understanding such factors as the desired release profiles, mechanisms of release, physicochemical characteristics of polymeric nanoparticles, and externally-triggering stimuli are essential for designing and optimizing such delivery systems. This review surveys the recent studies on the desired release profiles of GFs in various tissue engineering applications, elucidates the major release mechanisms and critical factors affecting release profiles, and overviews the role played by the mathematical models for optimizing nano-particulate delivery systems. Potentials of stimuli responsive nanoparticles for spatiotemporal control of GF release are also presented, along with the recent advances in strategies for spatiotemporal control of GF delivery within tissue engineered scaffolds. The recommendation for the future studies to overcome challenges for developing sophisticated particulate delivery systems in tissue engineering is discussed prior to the presentation of conclusions drawn from this paper.

  1. Prototype Systems for Measuring Outdoor Air Intake Rates in Rooftop Air Handlers

    SciTech Connect

    Fisk, William J.; Chan, Wanyu R.; Hotchi, Toshifumi

    2015-01-01

    The widespread absence of systems for real-time measurement and feedback control, of minimum outdoor air intake rates in HVAC systems contributes to the poor control of ventilation rates in commercial buildings. Ventilation rates affect building energy consumption and influence occupant health. The project designed fabricated and tested four prototypes of systems for measuring rates of outdoor air intake into roof top air handlers. All prototypes met the ±20% accuracy target at low wind speeds, with all prototypes accurate within approximately ±10% after application of calibration equations. One prototype met the accuracy target without a calibration. With two of four prototype measurement systems, there was no evidence that wind speed or direction affected accuracy; however, winds speeds were generally below usually 3.5 m s-1 (12.6 km h-1) and further testing is desirable. The airflow resistance of the prototypes was generally less than 35 Pa at maximum RTU air flow rates. A pressure drop of this magnitude will increase fan energy consumption by approximately 4%. The project did not have resources necessary to estimate costs of mass produced systems. The retail cost of components and materials used to construct prototypes ranged from approximately $1,200 to $1,700. The test data indicate that the basic designs developed in this project, particularly the designs of two of the prototypes, have considerable merit. Further design refinement, testing, and cost analysis would be necessary to fully assess commercial potential. The designs and test results will be communicated to the HVAC manufacturing community.

  2. Cesarean Delivery Rates Vary 10-Fold Among US Hospitals; Reducing Variation May Address Quality, Cost Issues

    PubMed Central

    Kozhimannil, Katy Backes; Law, Michael R.; Virnig, Beth A.

    2013-01-01

    Cesarean delivery is the most commonly performed surgical procedure in the United States, and cesarean rates are increasing. Working with 2009 data from 593 US hospitals nationwide, we found that cesarean rates varied tenfold across hospitals, from 7.1 percent to 69.9 percent. Even for women with lower-risk pregnancies, in which more limited variation might be expected, cesarean rates varied fifteen-fold, from 2.4 percent to 36.5 percent. Thus, vast differences in practice patterns are likely to be driving the costly overuse of cesarean delivery in many US hospitals. Because Medicaid pays for nearly half of US births, government efforts to decrease variation are warranted. We focus on four promising directions for reducing these variations, including better coordination of maternity care, more data collection and measurement, tying Medicaid payment to quality improvement, and enhancing patient-centered decision making through public reporting. PMID:23459732

  3. Air exchange rates from atmospheric CO2 daily cycle.

    PubMed

    Carrilho, João Dias; Mateus, Mário; Batterman, Stuart; da Silva, Manuel Gameiro

    2015-04-01

    We propose a new approach for measuring ventilation air exchange rates (AERs). The method belongs to the class of tracer gas techniques, but is formulated in the light of systems theory and signal processing. Unlike conventional CO2 based methods that assume the outdoor ambient CO2 concentration is constant, the proposed method recognizes that photosynthesis and respiration cycle of plants and processes associated with fuel combustion produce daily, quasi-periodic, variations in the ambient CO2 concentrations. These daily variations, which are within the detection range of existing monitoring equipment, are utilized for estimating ventilation rates without the need of a source of CO2 in the building. Using a naturally-ventilated residential apartment, AERs obtained using the new method compared favorably (within 10%) to those obtained using the conventional CO2 decay fitting technique. The new method has the advantages that no tracer gas injection is needed, and high time resolution results are obtained.

  4. Air quality assessment and control of emission rates.

    PubMed

    Skiba, Yuri N; Parra-Guevara, David; Belitskaya, Davydova Valentina

    2005-12-01

    Mathematical methods based on the adjoint model approach are given for the air-pollution estimation and control in an urban region. A simple advection-diffusion-reaction model and its adjoint are used to illustrate the application of the methods. Dual pollution concentration estimates in ecologically important zones are derived and used to develop two non-optimal strategies and one optimal strategy for controlling the emission rates of enterprises. A linear convex combination of these strategies represents a new sufficient strategy. A method for detecting the enterprises, which violate the emission rates prescribed by a control, is given. A method for determining an optimal position for a new enterprise in the region is also described.

  5. Air exchange rates from atmospheric CO2 daily cycle

    PubMed Central

    Carrilho, João Dias; Mateus, Mário; Batterman, Stuart; da Silva, Manuel Gameiro

    2015-01-01

    We propose a new approach for measuring ventilation air exchange rates (AERs). The method belongs to the class of tracer gas techniques, but is formulated in the light of systems theory and signal processing. Unlike conventional CO2 based methods that assume the outdoor ambient CO2 concentration is constant, the proposed method recognizes that photosynthesis and respiration cycle of plants and processes associated with fuel combustion produce daily, quasi-periodic, variations in the ambient CO2 concentrations. These daily variations, which are within the detection range of existing monitoring equipment, are utilized for estimating ventilation rates without the need of a source of CO2 in the building. Using a naturally-ventilated residential apartment, AERs obtained using the new method compared favorably (within 10%) to those obtained using the conventional CO2 decay fitting technique. The new method has the advantages that no tracer gas injection is needed, and high time resolution results are obtained. PMID:26236090

  6. Heart-rate monitoring by air pressure and causal analysis

    NASA Astrophysics Data System (ADS)

    Tsuchiya, Naoki; Nakajima, Hiroshi; Hata, Yutaka

    2011-06-01

    Among lots of vital signals, heart-rate (HR) is an important index for diagnose human's health condition. For instance, HR provides an early stage of cardiac disease, autonomic nerve behavior, and so forth. However, currently, HR is measured only in medical checkups and clinical diagnosis during the rested state by using electrocardiograph (ECG). Thus, some serious cardiac events in daily life could be lost. Therefore, a continuous HR monitoring during 24 hours is desired. Considering the use in daily life, the monitoring should be noninvasive and low intrusive. Thus, in this paper, an HR monitoring in sleep by using air pressure sensors is proposed. The HR monitoring is realized by employing the causal analysis among air pressure and HR. The causality is described by employing fuzzy logic. According to the experiment on 7 males at age 22-25 (23 on average), the correlation coefficient against ECG is 0.73-0.97 (0.85 on average). In addition, the cause-effect structure for HR monitoring is arranged by employing causal decomposition, and the arranged causality is applied to HR monitoring in a setting posture. According to the additional experiment on 6 males, the correlation coefficient is 0.66-0.86 (0.76 on average). Therefore, the proposed method is suggested to have enough accuracy and robustness for some daily use cases.

  7. Relativistic collision rate calculations for electron-air interactions

    SciTech Connect

    Graham, G.; Roussel-Dupre, R.

    1992-12-16

    The most recent data available on differential cross sections for electron-air interactions are used to calculate the avalanche, momentum transfer, and energy loss rates that enter into the fluid equations. Data for the important elastic, inelastic, and ionizing processes are generally available out to electron energies of 1--10 kev. Prescriptions for extending these cross sections to the relativistic regime are presented. The angular dependence of the cross sections is included where data is available as is the doubly differential cross section for ionizing collisions. The collision rates are computed by taking moments of the Boltzmann collision integrals with the assumption that the electron momentum distribution function is given by the Juettner distribution function which satisfies the relativistic H- theorem and which reduces to the familiar Maxwellian velocity distribution in the nonrelativistic regime. The distribution function is parameterized in terms of the electron density, mean momentum, and thermal energy and the rates are therefore computed on a two-dimensional grid as a function of mean kinetic energy and thermal energy.

  8. Relativistic collision rate calculations for electron-air interactions

    SciTech Connect

    Graham, G.; Roussel-Dupre, R.

    1993-12-01

    The most recent data available on differential cross sections for electron-air interactions are used to calculate the avalanche, momentum transfer, and energy loss rates that enter into the fluid equations. Data for the important elastic, inelastic, and ionizing processes are generally available out to electron energies of 1--10 keV. Prescriptions for extending these cross sections to the relativistic regime are presented. The angular dependence of the cross sections is included where data are available as is the doubly differential cross section for ionizing collisions. The collision rates are computed by taking moments of the Boltzmann collision integrals with the assumption that the electron momentum distribution function is given by the Juettner distribution function which satisfies the relativistic H- theorem and which reduces to the familiar Maxwellian velocity distribution in the nonrelativistic regime. The distribution function is parameterized in terms of the electron density, mean momentum, and thermal energy and the rates are therefore computed on a two dimensional grid as a function of mean kinetic energy and thermal energy.

  9. Dummies versus air puffs: efficient stimulus delivery for low-volatile odors.

    PubMed

    Brandstaetter, Andreas Simon; Rössler, Wolfgang; Kleineidam, Christoph Johannes

    2010-05-01

    Aiming to unravel how animals perceive odors, a variety of neurophysiological techniques are used today. For olfactory stimulation, odors are commonly incorporated into a constant airstream that carries odor molecules to the receptor organ (air-delivered stimulation). Such odor delivery works well for odors of high volatility (naturally effective over long distances) but less or not at all for low-volatile odors (usually only received at short range). We developed a new odor stimulation technique especially suited for low-volatile odors and compared it with conventional air-delivered stimulation using 2 neurophysiological approaches. Odor-loaded dummies were moved into close vicinity of the receptor organs on the antenna of the Florida carpenter ant Camponotus floridanus (dummy-delivered stimulation). Neuronal activity was monitored either at receptor neuron level using electroantennography or in the first olfactory neuropile, the antennal lobes, using calcium imaging. We tested 3 odors of different volatility: C. floridanus' highly volatile alarm pheromone undecane, its low-volatile trail pheromone nerolic acid, and an even less volatile, behaviorally active C23 alkene, cis-9-tricosene. For low-volatile odors, dummy-delivered stimulation was particularly efficient. We conclude that dummy-delivered stimulation is advantageous compared to the commonly used air-delivered stimulation when studying an animal's detection and processing of low-volatile odors.

  10. Heart rate, heart rate variability and behaviour of horses during air transport.

    PubMed

    Munsters, C C B M; de Gooijer, J-W; van den Broek, J; van Oldruitenborgh-Oosterbaan, M M Sloet

    2013-01-05

    Heart rate (HR), HR variability (HRV) and behaviour score (BS) of nine horses were evaluated during an eight-hour air transport between The Netherlands and New York. HR and HRV parameters were calculated every five minutes during the air transport. Compared with transit (40±3), mean HRs were higher during loading into the jet stall (67±21, P<0.001), loading into the aircraft (47±6, P=0.011), taxiing (50±8, P=0.001), and during periods of in-flight turbulence (46±7, P=0.017). During the flight, individual horses showed differences in mean HR (P=0.005) and peak HR (P<0.001). By contrast with HR data, HRV data did not differ between stages or horses. BS was highest during turbulence (3.2±0.4). However, behaviour did not always correspond with HR measurements: the least responsive horse had the highest HR. Loading into the jet stall caused the highest increase in HR and was considered the most stressful event. During transit, HR was generally comparable with resting rates. Previous studies have shown that loading and transporting by road caused more elevation in HR than during loading and transporting by air. HRV data were not found to be useful, and caution is needed when interpreting HRV data. Not every horse exhibited stress through visible (evasive) behaviour, and HR measurements may provide an additional tool to assess stress in horses.

  11. Exposure Modeling of Residential Air Exchange Rates for NEXUS Participants.

    EPA Science Inventory

    Due to cost and participant burden of personal measurements, air pollution health studies often estimate exposures using local ambient air monitors. Since outdoor levels do not necessarily reflect personal exposures, we developed the Exposure Model for Individuals (EMI) to improv...

  12. Exposure Modeling of Residential Air Exchange Rates for NEXUS Participants

    EPA Science Inventory

    Due to cost and participant burden of personal measurements, air pollution health studies often estimate exposures using local ambient air monitors. Since outdoor levels do not necessarily reflect personal exposures, we developed the Exposure Model for Individuals (EMI) to improv...

  13. Delivery of 1.9μm laser radiation using air-core Bragg fibers

    NASA Astrophysics Data System (ADS)

    Frank, Milan; Jelínek, Michal; Kubeček, Václav; Podrazký, Ondřej; Kašík, Ivan; Matějec, Vlastimil

    2016-12-01

    In this paper we have investigated Bragg fibers for the 1.94 μm laser- radiation delivery generated by a thulium fiber laser with a maximal continuous output power 50W. For such investigation laboratory-designed and fabricated hollow-core Bragg fibers have been employed with different diameters of 5, 40, 56 and 73 μm surrounded by three pairs of circular Bragg layers. Fundamental optical characteristics such as overall transmittance, attenuation coefficient, bending losses, and delivered spatial beam profiles at the wavelength of 1.94 μm for all tested fibers are reported and summarized in this contribution. In the case of laser radiation delivery with the intensity of 65 kW/cm2, the lowest attenuation coefficient of 1.278 dB/m was determined for the Bragg fiber with the inner air-core diameter of 56 μm. Moreover, the bending losses for a small bend diameter of 15 mm reached 0.177 dB only. However delivered laser radiation was highly multimode character.

  14. Fluence rate variability among light delivery devices for esophageal photodynamic therapy

    NASA Astrophysics Data System (ADS)

    Finlay, Jarod C.; Ginsberg, Gregory G.; Hahn, Stephen M.

    2007-02-01

    Esophageal photodynamic therapy (PDT) is performed using a photosensitizing agent activated by light delivered via a cylindrically symmetric delivery device containing a diffusing optical fiber. In PDT treatment of dysplastic Barrett's esophagus, considerable variability in results is observed due to the non-uniform delivery of treatment light caused by source geometry and by luminal collapse. We compare the fluence rate at the tissue surface resulting from illumination with bare fiber, a centering balloon catheter (X-Cell, Cooke, Inc), and a fixed diameter transparent dilating catheter (Optical Dilator, Inscope, Ethicon ES). Measurements were made in a solid esophagus-simulating phantom illuminated by 2.5 and 5 cm diffusing fibers with and without each delivery device. The diffuser was coupled to a 630 nm dye laser pumped by a 532 nm KTP laser (LaserScope, Inc.) The total power emitted by the diffuser was 1W. The fluence rate as a function of position along the cavity was measured by a calibrated photodiode connected to an optical fiber with a 0.5 mm isotropic scattering tip, which was moved by a computer-controlled positioner. The mean fluence rate measured when the phantom was illuminated using either the centering balloon or the rigid dilator was approximately 50% less than that measured with a bare fiber. The decrease in fluence rate is due to attenuation of the primary light beam and to reduction in scattering from laterally adjacent points in the phantom. The importance of each of these effects as a function of tissue optical properties was confirmed using Monte Carlo simulation.

  15. The Impact of Healthcare Reform Plan on the Rate of Vaginal Delivery and Cesarean Section in Shiraz (Iran) in 2015

    PubMed Central

    Rooeintan, Faranak; Borzabad, Parviz Aghaei; Yazdanpanah, Abbas

    2016-01-01

    Introduction The uncontrolled increase in the rate of cesarean section is one of the most controversial issues, and is a primary challenge among health policy makers. This study was conducted to examine the impact of the Iranian health evolution plan on vaginal delivery rate and cesarean section. Methods This cross-sectional study was carried out in 2014. Maternal health data for 2013 and 2014 were used in this study and changes in vaginal delivery and cesarean section were compared before and after the reform, using t-test and Wilkinson test. Results According to the findings of this study, 64.7% of deliveries in 2013 were performed using cesarean section while it was 58.6% in 2014 (p= 0.772), of which no significant changes were observed. In addition, the percentage of vaginal delivery in 2013 and 2014 were 35.3% and 41.4% respectively (p= 0.00), so a significant increase was found for vaginal delivery. Conclusion Healthcare reform has led to an increase in the number of vaginal deliveries in hospitals affiliated to Shiraz University of Medical Sciences (SUMS). Due to the limited number of hospitals adhering to the healthcare reform plan to increase vaginal delivery (using private midwife and implementing painless delivery), the reform for decreasing the cesarean rate was not effective enough. PMID:27957306

  16. Quality Control of High-Dose-Rate Brachytherapy: Treatment Delivery Analysis Using Statistical Process Control

    SciTech Connect

    Able, Charles M.; Bright, Megan; Frizzell, Bart

    2013-03-01

    Purpose: Statistical process control (SPC) is a quality control method used to ensure that a process is well controlled and operates with little variation. This study determined whether SPC was a viable technique for evaluating the proper operation of a high-dose-rate (HDR) brachytherapy treatment delivery system. Methods and Materials: A surrogate prostate patient was developed using Vyse ordnance gelatin. A total of 10 metal oxide semiconductor field-effect transistors (MOSFETs) were placed from prostate base to apex. Computed tomography guidance was used to accurately position the first detector in each train at the base. The plan consisted of 12 needles with 129 dwell positions delivering a prescribed peripheral dose of 200 cGy. Sixteen accurate treatment trials were delivered as planned. Subsequently, a number of treatments were delivered with errors introduced, including wrong patient, wrong source calibration, wrong connection sequence, single needle displaced inferiorly 5 mm, and entire implant displaced 2 mm and 4 mm inferiorly. Two process behavior charts (PBC), an individual and a moving range chart, were developed for each dosimeter location. Results: There were 4 false positives resulting from 160 measurements from 16 accurately delivered treatments. For the inaccurately delivered treatments, the PBC indicated that measurements made at the periphery and apex (regions of high-dose gradient) were much more sensitive to treatment delivery errors. All errors introduced were correctly identified by either the individual or the moving range PBC in the apex region. Measurements at the urethra and base were less sensitive to errors. Conclusions: SPC is a viable method for assessing the quality of HDR treatment delivery. Further development is necessary to determine the most effective dose sampling, to ensure reproducible evaluation of treatment delivery accuracy.

  17. Delivery

    PubMed Central

    Miller, Thomas A

    2013-01-01

    Enthusiasm greeted the development of synthetic organic insecticides in the mid-twentieth century, only to see this give way to dismay and eventually scepticism and outright opposition by some. Regardless of how anyone feels about this issue, insecticides and other pesticides have become indispensable, which creates something of a dilemma. Possibly as a result of the shift in public attitude towards insecticides, genetic engineering of microbes was first met with scepticism and caution among scientists. Later, the development of genetically modified crop plants was met with an attitude that hardened into both acceptance and hard-core resistance. Transgenic insects, which came along at the dawn of the twenty-first century, encountered an entrenched opposition. Those of us responsible for studying the protection of crops have been affected more or less by these protagonist and antagonistic positions, and the experiences have often left one thoughtfully mystified as decisions are made by non-participants. Most of the issues boil down to concerns over delivery mechanisms. © 2013 Society of Chemical Industry PMID:23852646

  18. Peer Ratings: Scoring Strategy Development and Reliability Demonstration on Air Force Basic Trainees. Final Report.

    ERIC Educational Resources Information Center

    Borman, Walter C.; Rosse, Rodney L.

    As an alternative for or adjunct to paper-and-pencil tests for predicting personnel performance, the United States Air Force studied the use of peer ratings as an evaluative tool. Purpose of this study was to evaluate the psychometric characteristics of peer ratings among Air Force basic trainees. Peer ratings were obtained from more than 27,000…

  19. Statistical analysis of oxidation rates for K Basin fuel in dry air

    SciTech Connect

    Trimble, D.J.

    1998-02-06

    Test data from oxidation of K Basin fuel (SNF) samples in dry air were reviewed, and linear reaction rates were derived on a time-average basis. The derived rates were compared to literature data for unirradiated uranium in dry air using rate law of the form log(rate) = a + b (I/T). The analyses found differences between the SNF data and the literature data. Oxidation rate below 150 C was higher for K Basin fuel than for unirradiated uranium.

  20. Probabilistic estimation of residential air exchange rates for population-based human exposure modeling

    EPA Science Inventory

    Residential air exchange rates (AERs) are a key determinant in the infiltration of ambient air pollution indoors. Population-based human exposure models using probabilistic approaches to estimate personal exposure to air pollutants have relied on input distributions from AER meas...

  1. Effect of wind tunnel air velocity on VOC flux rates from CAFO manure and wastewater

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wind tunnels and flux chambers are often used to estimate volatile organic compound (VOC) emissions from animal feeding operations (AFOs) without regard to air velocity or sweep air flow rates. Laboratory experiments were conducted to evaluate the effect of wind tunnel air velocity on VOC emission ...

  2. Delivery by Cesarean Section is not Associated With Decreased at-Birth Fracture Rates in Osteogenesis Imperfecta

    PubMed Central

    Bellur, S; Jain, M; Cuthbertson, D; Krakow, D; Shapiro, JR; Steiner, RD; Smith, PA; Bober, MB; Hart, T; Krischer, J; Mullins, M; Byers, PH; Pepin, M; Durigova, M; Glorieux, FH; Rauch, F; Sutton, VR; Lee, B; Nagamani, SC

    2015-01-01

    Purpose Osteogenesis imperfecta (OI) predisposes to recurrent fractures. The moderate-to-severe forms of OI present with antenatal fractures and the mode of delivery that would be safest for the fetus is not known. Methods We conducted systematic analyses on the largest cohort of individuals (n=540) with OI enrolled to-date in the OI Linked Clinical Research Centers. Self-reported at-birth fracture rates were compared in individuals with OI types I, III, and IV. Multivariate analyses utilizing backward-elimination logistic regression model building were performed to assess the effect of multiple covariates including method of delivery on fracture-related outcomes. Results When accounting for other covariates, at-birth fracture rates did not differ based on whether delivery was by vaginal route or by cesarean section (CS). Increased birth weight conferred higher risk for fractures irrespective of the delivery method. In utero fracture, maternal history of OI, and breech presentation were strong predictors for choosing CS for delivery. Conclusion Our study, the largest to analyze the effect of various factors on at-birth fracture rates in OI shows that delivery by CS is not associated with decreased fracture rate. With the limitation that the fracture data were self-reported in this cohort, these results suggest that CS should be performed only for other maternal or fetal indications, but not for the sole purpose of fracture prevention in OI. PMID:26426884

  3. Effect of delivery condition on desorption rate of ZrCo metal hydride bed for fusion fuel cycle

    SciTech Connect

    Kang, H.G.; Yun, S.H.; Chung, D.; Oh, Y.H.; Chang, M.H.; Cho, S.; Chung, H.; Song, K.M.

    2015-03-15

    For the safety of fusion fuel cycle, hydrogen isotope gases including tritium are stored as metal hydride form. To satisfy fueling requirement of fusion machine, rapid delivery from metal hydride bed is one of major factors for the development of tritium storage and delivery system. Desorption from metal hydride depends on the operation scenario by pressure and temperature control of the bed. The effect of operation scenario and pump performance on desorption rate of metal hydride bed was experimentally investigated using ZrCo bed. The results showed that the condition of pre-heating scenario before actual delivery of gas affected the delivery performance. Different pumps were connected to desorption line from bed and the effect of pump capacity on desorption rate were also found to be significant. (authors)

  4. Effect of air pollution on peak expiratory flow rate variability.

    PubMed

    Singh, Virendra; Khandelwal, Rakesh; Gupta, A B

    2003-02-01

    Exposure to air pollution affects pulmonary functions adversely. Effect of exposure to pollution on diurnal variation of peak flow was assessed in healthy students. Three hundred healthy age-matched nonsmoker students were studied. They were categorized into two groups on the basis of their residence: commuters and living on campus. Peak expiratory flow (PEF) recordings were made twice daily for 2 days with the Pink City Flow Meter. The measurement was then used to calculate for each subject the amplitude percentage mean, which is an index for expressing PEF variability for epidemiological purposes (Higgins BG, Britton JR, Chinns Jones TD, Jenkinson D, Burnery PG, Tattersfield AE. Distribution of peak expiratory flow variability in a population sample. Am Rev Respir Dis 1989; 140:1368-1372). Air pollution parameters were quantified by measurement of sulfur dioxide (SO2), oxides of nitrogen (NO2), carbon monoxide (CO), and respirable suspended particulate matter (RSPM) in the ambient air at the campus and on the roadside. The mean values of PEF variability (amplitude percent mean) in the students living on campus and in the commuters were 5.7 +/- 3.2 and 11 +/- 3.6, respectively (P < .05). Among the commuters, maximum number of subjects showed amplitude percentage mean PEFR at the higher end of variability distribution, as compared to the students living on campus, among whom the majority of subjects fell in the lower ranges of variability distribution. The ambient air quality parameters, namely SO2, NO2, CO, and RSPM were significantly lower on the campus. It can be concluded that long-term periodic exposure to air pollution can lead to increased PEF variability even in healthy subjects. Measurement of PEF variability may prove to be a simple test to measure effect of air pollution in healthy subjects.

  5. Spatiotemporally‐Resolved Air Exchange Rate as a Modifier of Acute Air Pollution‐Related Morbidity in AtlantaMorbidity in Atlanta

    EPA Science Inventory

    Epidemiological studies frequently use central site concentrations as surrogates of exposure to air pollutants. Variability in air pollutant infiltration due to differential air exchange rates (AERs) is potentially a major factor affecting the relationship between central site c...

  6. Diet, prey delivery rates, and prey biomass of Northern Goshawks in East-Central Arizona

    USGS Publications Warehouse

    Rogers, A.S.; DeStefano, S.; Ingraldi, M.F.

    2006-01-01

    Recent concern over persistence of Northern Goshawk (Accipiter gentilis) populations in Arizona has stemmed from two long-term demography studies that report substantial yearly fluctuations in productivity and evidence of a declining population. Although many factors could be involved in changes in productivity and population declines, availability of food is one such factor. As part of a demography study on the Sitgreaves portion of the Apache-Sitgreaves National Forest in Arizona, we used remote cameras to assess diets of goshawks. Northern Goshawks preyed upon 22 species during two nesting seasons. Adult pairs tended to specialize on particular species of prey. Prey delivery rates decreased throughout the nesting season with a corresponding increase in biomass in the latter stages of the nestling and fledgling periods. Adults appeared to take larger prey as nestlings increased in age.

  7. Effects of energy-efficient ventilation rates on indoor air quality at an Ohio elementary school

    NASA Astrophysics Data System (ADS)

    Berk, J. V.; Young, R.; Hollowell, C. D.; Turiel, I.; Pepper, J.

    1980-04-01

    A mobile laboratory was used to monitor air outdoors and at three indoor sites (two classrooms and a large multipurpose room); tests were made at three different ventilation rates. The parameters measured were outside air flow rates, odor perception, microbial burden, particulate mass, total aldehydes, carbon dioxide, ozone, and nitrogen oxides. The results of these measurements are given and compared with the existing outdoor air quality standards. Carbon dioxide concentrations increased as the ventilation rate decreased, but still did not exceed current standards. Odor perceptibility increased slightly at the lowest ventilation rate. Other pollutants showed very low concentrations, which did not change with reductions in ventilation rate.

  8. Increasing Rates of Tobacco Treatment Delivery in Primary Care Practice: Evaluation of the Ottawa Model for Smoking Cessation

    PubMed Central

    Papadakis, Sophia; Cole, Adam G.; Reid, Robert D.; Coja, Mustafa; Aitken, Debbie; Mullen, Kerri-Anne; Gharib, Marie; Pipe, Andrew L.

    2016-01-01

    PURPOSE We report on the effectiveness of the Ottawa Model for Smoking Cessation (OMSC), a multicomponent knowledge translation intervention, in increasing the rate at which primary care providers delivered smoking cessation interventions using the 3 A’s model—Ask, Advise, and Act, and examine clinic-, provider-and patient-level determinants of 3 A’s delivery. METHODS We examined the effect of the knowledge translation intervention in 32 primary care practices in Ontario, Canada, by assessing a cross-sectional sample of patients before the implementation of the OMSC and a second cross-sectional sample following implementation. We used 3-level modeling (clinic, clinician, patient) to examine the main effects and predictors of 3 A’s delivery. RESULTS Four hundred eighty-one primary care clinicians and more than 3,500 tobacco users contributed data to the evaluation. Rates of delivery of the 3 A’s increased significantly following program implementation (Ask: 55.3% vs 71.3%, P <.001; Advise: 45.5% vs 63.6%, P <.001; Act: 35.4% vs 54.4%, P <.001). The adjusted odds ratios (AOR) for the delivery of 3 A’s between the pre- and post-assessments were AOR = 1.94; (95% CI, 1.61–2.34) for Ask, AOR = 1.92; (95% CI, 1.60–2.29) for Advise, and AOR = 2.03; (95% CI, 1.71–2.42) for Act. The quality of program implementation and the reason for clinic visit were associated with increased rates of 3 A’s delivery. CONCLUSIONS Implementation of the OMSC was associated with increased rates of smoking cessation treatment delivery. High quality implementation of the OMSC program was associated with increased rates of 3 A’s delivery. PMID:27184994

  9. Resistance to change of alcohol self-administration: effects of alcohol-delivery rate on disruption by extinction and naltrexone.

    PubMed

    Jimenez-Gomez, Corina; Shahan, Timothy A

    2007-03-01

    A common finding in resistance to change research with food-maintained operant behavior is that the persistence of behavior depends on the rate of reinforcement delivered in the context in which the behavior occurs. The present experiment evaluated the effects of rate of response-dependent alcohol delivery on the resistance to change of rats' alcohol self-administration in the face of disruption produced by extinction and a range of doses of naltrexone (1.0, 3.0, 10.0 mg/kg, subcutaneous). Rats responded for a 10% alcohol solution in a multiple schedule of reinforcement arranging a higher rate of alcohol delivery (variable interval 15 s) in the presence of one stimulus and a lower rate of alcohol delivery (variable interval 45 s) in the presence of another stimulus. Baseline response rates and resistance to extinction were higher in the presence of the stimulus associated with higher rates of alcohol delivery. This finding is consistent with studies of the resistance to change of food-maintained behavior. The rate of alcohol delivered in the components, however, did not systematically affect resistance to disruption by naltrexone. One interpretation of this finding from the perspective of behavioral momentum theory is that naltrexone may decrease the impact of alcohol-associated stimuli on the persistence of drinking by reducing sensitivity to the relative reinforcement conditions arranged in the presence of different stimuli.

  10. Bioactive silica-based nanomaterials for doxorubicin delivery: evaluation of structural properties associated with release rate.

    PubMed

    Prokopowicz, Magdalena

    2013-10-01

    This study investigated the use of a novel particle-type formulation, composed of a sol-gel derived bioactive silica-poly(dimethylsiloxane) composite containing calcium and phosphate, as a slow release delivery system for an anticancer drug (doxorubicin hydrochloride, DOX). DOX in the solution form was in situ incorporated into the composite network during the sol-gel process. The DOX loaded-formulation was immersed in a simulated body fluid (SBF) having ion concentrations and a pH value nearly equal to those of human blood plasma. The effect of different drug loads and particle sizes - on the release profiles in such biomimetic conditions was studied. The bioactivity was examined in vitro with respect to the ability of hydroxyapatite layer to form on the surface of residual DOX-loaded formulation as a result of contact with SBF. The infrared absorption spectra, scanning electron microscopy, nitrogen gas adsorption/desorption, and X-ray powder diffraction studies were conducted before and after contact of the formulation with SBF. The results show that all the DOX-loaded formulations are characterized by mesoporosity with the uniform pore-size-distribution. The release profiles of DOX consisted of two sequential zero order-controlled stages with distinctly different release rates. After 20 days of DOX release, a semicrystalline carbonated hydroxyapatite with a highly developed porous structure was formed, indicative of their bioactive character. Furthermore, these new covered-particle-type formulations released DOX over 1 month at a constant rate.

  11. Power and Thermal Technologies for Air and Space-Scientific Research Program. Delivery Order 0012: High-Temperature Superconductor Performance Enhancement

    DTIC Science & Technology

    2010-06-01

    AFRL-RZ-WP-TR-2010-2167 POWER AND THERMAL TECHNOLOGIES FOR AIR AND SPACE‒SCIENTIFIC RESEARCH PROGRAM Delivery Order 0012: High -Temperature...AND SUBTITLE POWER AND THERMAL TECHNOLOGIES FOR AIR AND SPACE‒SCIENTIFIC RESEARCH PROGRAM Delivery Order 0012: High -Temperature Superconductor...electrically connect them to the substrate. 4) Develop improved measurement techniques and standards of measurement for properties of high temperature

  12. Absorbed dose rate in air in metropolitan Tokyo before the Fukushima Daiichi Nuclear Power Plant accident.

    PubMed

    Inoue, K; Hosoda, M; Fukushi, M; Furukawa, M; Tokonami, S

    2015-11-01

    The monitoring of absorbed dose rate in air has been carried out continually at various locations in metropolitan Tokyo after the accident of the Fukushima Daiichi Nuclear Power Plant. While the data obtained before the accident are needed to more accurately assess the effects of radionuclide contamination from the accident, detailed data for metropolitan Tokyo obtained before the accident have not been reported. A car-borne survey of the absorbed dose rate in air in metropolitan Tokyo was carried out during August to September 2003. The average absorbed dose rate in air in metropolitan Tokyo was 49±6 nGy h(-1). The absorbed dose rate in air in western Tokyo was higher compared with that in central Tokyo. Here, if the absorbed dose rate indoors in Tokyo is equivalent to that outdoors, the annual effective dose would be calculated as 0.32 mSv y(-1).

  13. A Review of the Thermodynamic, Transport, and Chemical Reaction Rate Properties of High-temperature Air

    NASA Technical Reports Server (NTRS)

    Hansen, C Frederick; Heims, Steve P

    1958-01-01

    Thermodynamic and transport properties of high temperature air, and the reaction rates for the important chemical processes which occur in air, are reviewed. Semiempirical, analytic expressions are presented for thermodynamic and transport properties of air. Examples are given illustrating the use of these properties to evaluate (1) equilibrium conditions following shock waves, (2) stagnation region heat flux to a blunt high-speed body, and (3) some chemical relaxation lengths in stagnation region flow.

  14. Effect of air-flow rate and turning frequency on bio-drying of dewatered sludge.

    PubMed

    Zhao, Ling; Gu, Wei-Mei; He, Pin-Jing; Shao, Li-Ming

    2010-12-01

    Sludge bio-drying is an approach for biomass energy utilization, in which sludge is dried by means of the heat generated by aerobic degradation of its organic substances. The study aimed at investigating the interactive influence of air-flow rate and turning frequency on water removal and biomass energy utilization. Results showed that a higher air-flow rate (0.0909m(3)h(-1)kg(-1)) led to lower temperature than did the lower one (0.0455m(3)h(-1)kg(-1)) by 17.0% and 13.7% under turning per two days and four days. With the higher air-flow rate and lower turning frequency, temperature cumulation was almost similar to that with the lower air-flow rate and higher turning frequency. The doubled air-flow rate improved the total water removal ratio by 2.86% (19.5gkg(-1) initial water) and 11.5% (75.0gkg(-1) initial water) with turning per two days and four days respectively, indicating that there was no remarkable advantage for water removal with high air-flow rate, especially with high turning frequency. The heat used for evaporation was 60.6-72.6% of the total heat consumption (34,400-45,400kJ). The higher air-flow rate enhanced volatile solids (VS) degradation thus improving heat generation by 1.95% (800kJ) and 8.96% (3200kJ) with turning per two days and four days. With the higher air-flow rate, heat consumed by sensible heat of inlet air and heat utilization efficiency for evaporation was higher than the lower one. With the higher turning frequency, sensible heat of materials and heat consumed by turning was higher than lower one.

  15. Modeling exposure close to air pollution sources in naturally ventilated residences: association of turbulent diffusion coefficient with air change rate.

    PubMed

    Cheng, Kai-Chung; Acevedo-Bolton, Viviana; Jiang, Ruo-Ting; Klepeis, Neil E; Ott, Wayne R; Fringer, Oliver B; Hildemann, Lynn M

    2011-05-01

    For modeling exposure close to an indoor air pollution source, an isotropic turbulent diffusion coefficient is used to represent the average spread of emissions. However, its magnitude indoors has been difficult to assess experimentally due to limitations in the number of monitors available. We used 30-37 real-time monitors to simultaneously measure CO at different angles and distances from a continuous indoor point source. For 11 experiments involving two houses, with natural ventilation conditions ranging from <0.2 to >5 air changes per h, an eddy diffusion model was used to estimate the turbulent diffusion coefficients, which ranged from 0.001 to 0.013 m² s⁻¹. The model reproduced observed concentrations with reasonable accuracy over radial distances of 0.25-5.0 m. The air change rate, as measured using a SF₆ tracer gas release, showed a significant positive linear correlation with the air mixing rate, defined as the turbulent diffusion coefficient divided by a squared length scale representing the room size. The ability to estimate the indoor turbulent diffusion coefficient using two readily measurable parameters (air change rate and room dimensions) is useful for accurately modeling exposures in close proximity to an indoor pollution source.

  16. Self-Nanoemulsified Drug Delivery System of Hydrochlorothiazide for Increasing Dissolution Rate and Diuretic Activity.

    PubMed

    Mendes, Cassiana; Buttchevitz, Aline; Kruger, Jéssica Henriques; Caon, Thiago; de Oliveira Benedet, Patricia; Lemos-Senna, Elenara; Silva, Marcos Antônio Segatto

    2017-02-17

    Hydrochlorothiazide (HCTZ) is a class IV drug according to the Biopharmaceutical Classification System. This study aimed the development of self-nanoemulsifying drug delivery system (SNEDDS) for HCTZ as an approach to overcome the biopharmaceutical limitations. Pre-formulation screening and ternary phase diagrams were carried out to select the oil phase, the surfactant, and the co-surfactant as the amount of each constituent. The optimized formulations, with reduced amount of surfactant, and composed of medium chain triglycerides, Cremophor EL and Transcutol P did not affect the pH or show drug incompatibilities. The SNEDDS were stabilized by the nanoscale globules and high negative zeta potential. All the physicochemical characterization assays were performed in biorelevant media to better predict the in vivo performance. The enhanced dissolution rate of the SNEDDS reflected in the in vivo diuretic activity, presenting a natriuresis, kaliuresis, and chloriuresis at early stages and an increased volume of total urine compared with HCTZ alone. The designed SNEDDS produced an improvement in the pharmacodynamics due to high dissolution and probable inhibition of intestinal efflux protein by Cremophor EL. The use of SNEDDS demonstrated to be an efficient approach to modulate the absorption of HCTZ and drug therapeutics.

  17. Effect of bait delivery rate in a GreenFeed system on methane emission estimates from cattle grazing rangeland

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Two experiments were conducted to evaluate the effect of bait delivery rate on methane emission estimates measured by a GreenFeed system (GFS; C-Lock, Inc., Rapid City, SD). The manufacture recommends that cattle have a minimum visit time of 3 minutes so that at least 3 eructations are captured to ...

  18. Temporal Variations of Air Dose Rates in East Fukushima During Japanese Fiscal Years 2012 and 2013.

    PubMed

    Akimoto, Kazuhiro

    2017-01-01

    Temporal variations of ambient air dose rates in eastern Fukushima prefecture during Japanese fiscal years 2012 and 2013 are analyzed. The average overall variation rate of air dose rates in east Fukushima during the examined period is found to be 0.49 (51% down) compared to the theoretically predicted value 0.65 (35% down) based on physical decay of radioactive cesium nuclides. On average, local dose rates declined almost linearly for the relatively short period. Temporal characteristics of air dose rates may be classified into variation rates, peaks, spikes, and oscillations. During the examined period, a typical dose-rate curve formed a long-term peak in summer that lasted one through a few months as well as a long-term spike in winter that lasted likewise. Otherwise, occasional short-term peaks and short-term spikes, in addition to long-term oscillations, were observed. Air dose rates may be effectively modulated at short timescales mainly by precipitation. Moreover, it is likely that winds may oscillate air dose rates due to resuspension of radio-dusts.

  19. Correlation of mutagenic assessment of Houston air particulate extracts in relation to lung cancer mortality rates

    SciTech Connect

    Walker, R.D.; Connor, T.H.; MacDonald, E.J.; Trieff, N.M.; Legator, M.S.; MacKenzie, K.W. Jr.; Dobbins, J.G.

    1982-08-01

    Air particulate extracts from a series of solvents were tested in the Ames mutagen detection system and were found to be mutagenic in varying degrees as a function of the particulate collection site in Houston, Texas. The mutagenicity level at seven sites was compared with age-adjusted mortality rates in the same areas. Significant correlation was found with the lung cancer mortality rates but not with mortality rates for other causes. These findings support the hypothesis of a contribution of urban air particulate to the lung cancer rates. Furthermore, these findings suggest that an index of the mutagenicity of air particulate is a more powerful measure of the human health hazard of air pollution than the traditional indices of particulate concentration.

  20. Refinement of the Air Force Systems Command Production Rate Model

    DTIC Science & Technology

    1989-09-01

    the recommended modified formulations. The relationship between production rate and production ratio has a definite influence on the model’s ability to...1984 7 36 21.954 370.00 1985 8 48 21.017 412.00 A- 3 Table A.2.8 F-15E Cost/Quantity Data Fiscal Year Lot Quntit Recurring Unit Cost LPP 1986 1 60

  1. Air Vehicle Technology Integration Program (AVTIP) Delivery Order 0015: Open Control Platform (OCP) Software Enabled Control (SEC) Hardware in the Loop Simulation - OCP Hardware Integration

    DTIC Science & Technology

    2005-06-01

    AFRL-VA-WP-TR-2006-3075 AIR VEHICLE TECHNOLOGY INTEGRATION PROGRAM (AVTIP) Delivery Order 0015: Open Control Platform (OCP) Software Enabled...2001– 05/28/2004 5a. CONTRACT NUMBER F33615-00-D-3052-0015 5b. GRANT NUMBER 4. TITLE AND SUBTITLE AIR VEHICLE TECHNOLOGY INTEGRATION PROGRAM

  2. Spatiotemporally-Resolved Air Exchange Rate as a Modifier of Acute Air Pollution-Related Morbidity

    EPA Science Inventory

    The National Exposure Research Laboratory (NERL) Human Exposure and Atmospheric Sciences Division (HEASD) conducts research in support of EPA mission to protect human health and the environment. HEASD research program supports Goal 1 (Clean Air) and Goal 4 (Healthy People) of EP...

  3. Modulation of the cell membrane expression of the kininogens regulates the rate of bradykinin delivery to cells.

    PubMed

    Schmaier, A H

    1992-01-01

    The kininogens were first recognized as the parent molecules for bradykinin. Their relative physiologic importance in plasma hemostasis and fibrinolysis and tissue cysteine protease inhibition has not been clarifed. Recent studies on the structure and function of the plasma kininogens, their interaction with cells of the intravascular compartment, and clinical investigations on contact system activation have refocused the physiologic importance of these proteins to kinin delivery for the maintance of vasodilatory tone. Kininogen expression on platelets slows the rate of kinin liberation, and kinins upregulate kininogen expression on endothelial cells. Regulation of kinin delivery by influencing kininogen expression may provide for new agents to manipulate blood pressure.

  4. Variations of the ambient dose equivalent rate in the ground level air.

    PubMed

    Lebedyte, M; Butkus, D; Morkŭnas, G

    2003-01-01

    The ambient dose equivalent rate is caused by ionizing radiation of radionuclides in the atmosphere and on the ground surface as well as by cosmic radiation. Seasonal and diurnal variations of the ambient dose equivalent rate (ADER) in the ground level air are influenced by the concentration of 222Rn daughters. The 222Rn concentration in the ground level atmosphere, in turn, depends on the rate of the 222Rn exhalation from soil and turbulent air mixing. Its diurnal and seasonal variations depend on meteorological conditions. The aim of this study is to estimate the influence of variations of the rate of the 222Rn exhalation from soil and its concentrations in the ground level air on variations of ADER in the ground level air, as well as the dependence of these parameters on meteorological conditions. The 222Rn diffusion coefficient and its exhalation rate in undisturbed loamy soil have been determined. The 222Rn concentration in the soil air and its concentration in the ground level air correlate inversely (correlation coefficient is r = -0.62). The main factors determining the 222Rn exhalation from soil are: the soil temperature (r = 0.64), the difference in temperature of soil and air (r = 0.57), and the precipitation amount (r = 0.50). The intensity of gamma radiation in the ground level air is mostly related to the 222Rn concentration in the air (r = 0.62), while the effect of the exhalation rate from soil is relatively low (r = 0.36). It has been shown that ADER due to 222Rn progeny causes only 7-16% of the total ADER and influences its variation. The comparison of variations of ADER due to 222Rn progeny and the total ADER during several years shows that these parameters correlate positively.

  5. Changes in Cesarean Delivery Rates by Gestational Age: United States, 1996-2011

    MedlinePlus

    ... this change on maternal and infant health outcomes. Definitions Cesarean delivery : Extraction of the infant, placenta, and ... statistics: Trends, outcomes and measurement. Rockville, MD: NICHD Definition of Term Workshop. 2012. American College of Obstetricians ...

  6. Nanostructured thin film polymer devices for constant-rate protein delivery.

    PubMed

    Bernards, Daniel A; Lance, Kevin D; Ciaccio, Natalie A; Desai, Tejal A

    2012-10-10

    Herein long-term delivery of proteins from biodegradable thin film devices is demonstrated, where a nanostructured polymer membrane controls release. Protein was sealed between two poly(caprolactone) films, which generated the thin film devices. Protein release for 210 days was shown in vitro, and stable activity was established through 70 days with a model protein. These thin film devices present a promising delivery platform for biologic therapeutics, particularly for application in constrained spaces.

  7. Meloxicam transdermal delivery: effect of eutectic point on the rate and extent of skin permeation

    PubMed Central

    Mohammadi-Samani, Soliman; Yousefi, Gholamhossein; Mohammadi, Farhad; Ahmadi, Fatemeh

    2014-01-01

    Objective(s): Drug delivery through the skin can transfer therapeutic levels of drugs for pharmacological effects. Analgesics such as NSAIDs have gastrointestinal side effects and topical dosage forms of these drugs are mainly preferred, especially for local pains. Meloxicam is one of NSAIDs with no topical form in the market. In this research, we attempted to quantify the skin permeation of a meloxicam topical preparation and to show how permeation would be increased by using thymol as an enhancer. The effect of eutectic point of drug and thymol mixture on rate and extent of skin permeation was also studied. Materials and Methods: Different mixtures of thymol and meloxicam (2:8, 4:6, 5:5, 6:4, 8:2) were prepared and their melting point were obtained by differential scanning calorimetry. Then drug permeation was measured using diffusion cells and the Guinea pig skin. Results: Mixtures in ratios 5:5 and 4:6 of meloxicam / thymol showed a new endotherm at 149 and 140°C in DSC thermograms. The permeability of meloxicam from the creams containing 6:4, 5:5 and 4:6 ratios of meloxicam to thymol were 4.71, 15.2, 22.06 µg/cm2 respectively. This was significantly different from the cream of pure meloxicam (3.76 µg/cm2). Conclusion: This study set out to determine that thymol plays as a skin permeation enhancer and increases the meloxicam skin absorption and this enhancement is significant at the eutectic point of drug-enhancer mixture. PMID:24711894

  8. Non-Rated Air Force Line Officer Attrition Rates Using Survival Analysis

    DTIC Science & Technology

    2015-03-26

    required and expected . Additionally, the experience they gather throughout their careers is invaluable to the success of the Air Force and cannot be...The service commitments and career paths tend to be relatively equal within this group, so the attrition behavior was expected to be approximately the... females , given that they are in the same yeargroup, career field, etc. Although the actual reason cannot be determined based on this data, one can attribute

  9. Compensating for the impact of non-stationary spherical air cavities on IMRT dose delivery in transverse magnetic fields.

    PubMed

    Bol, G H; Lagendijk, J J W; Raaymakers, B W

    2015-01-21

    With the development of the 1.5 T MRI linear accelerator and the clinical introduction of the 0.35 T ViewRay™ system, delivering intensity-modulated radiotherapy (IMRT) in a transverse magnetic field becomes increasingly important. When delivering dose in the presence of a transverse magnetic field, one of the most prominent phenomena occurs around air cavities: the electron return effect (ERE). For stationary, spherical air cavities which are centrally located in the phantom, the ERE can be compensated by using opposing beams configurations in combination with IMRT. In this paper we investigate the effects of non-stationary spherical air cavities, centrally located within the target in a phantom containing no organs at risk, on IMRT dose delivery in 0.35 T and 1.5 T transverse magnetic fields by using Monte Carlo simulations. We show that IMRT can be used for compensating ERE around those air cavities, except for intrafraction appearing or disappearing air cavities. For these cases, gating or plan re-optimization should be used. We also analyzed the option of using IMRT plans optimized at 0 T to be delivered in the presence of 0.35 T and 1.5 T magnetic field. When delivering dose at 0.35 T, IMRT plans optimized at 0 T and 0.35 T perform equally well regarding ERE compensation. Within a 1.5 T environment, the 1.5 T optimized plans perform slightly better for the static and random intra- and interfraction air cavity movement cases than the 0 T optimized plans. For non-stationary spherical air cavities with a baseline shift (intra- and interfraction) the 0 T optimized plans perform better. These observations show the intrinsic ERE compensation by equidistant and opposing beam configurations for spherical air cavities within the target area. IMRT gives some additional compensation, but only in case of correct positioning of the air cavity according to the IMRT compensation. For intrafraction appearing or disappearing air cavities this correct positioning is absent

  10. A Detailed Assessment of Varying Ejection Rate on Delivery Efficiency of Mesenchymal Stem Cells Using Narrow-Bore Needles

    PubMed Central

    Amer, Mahetab H.; Rose, Felicity R.A.J.; White, Lisa J.

    2016-01-01

    As the number of clinical trials exploring cell therapy rises, a thorough understanding of the limits of cell delivery is essential. We used an extensive toolset comprising various standard and multiplex assays for the assessment of cell delivery postejection. Primary human mesenchymal stem cell (hMSC) suspensions were drawn up into 100-µl Hamilton syringes with 30- and 34-gauge needles attached, before being ejected at rates ranging from 10 to 300 µl/minute. Effects of ejection rate, including changes in viability, apoptosis, senescence, and other key aspects of cellular health, were evaluated. Ejections at slower flow rates resulted in a lower percentage of the cell dose being delivered, and apoptosis measurements of samples ejected at 10 µl/minute were significantly higher than control samples. Immunophenotyping also revealed significant downregulation of CD105 expression in samples ejected at 10 µl/minute (p < .05). Differentiation of ejected hMSCs was investigated using qualitative markers of adipogenesis, osteogenesis, and chondrogenesis, which revealed that slower ejection rates exerted a considerable effect upon the differentiation capacity of ejected cells, thereby possibly influencing the success of cell-based therapies. The findings of this study demonstrate that ejection rate has substantial impact on the percentage of cell dose delivered and cellular health postejection. Significance There are a growing number of clinical trials using mesenchymal stem cells (MSCs) for cellular therapy in a multitude of clinical targets. Numerous cell-therapy procedures use injection-based administration to deliver high-density cell preparations to the target site, either systemically or directly. However, there is growing evidence in the literature of a problem with cell injection methods in various cellular therapy applications. Because a thorough understanding of the limits of cell delivery is essential, an extensive toolset comprising various standard and

  11. Water-air and soil-air exchange rate of total gaseous mercury measured at background sites

    NASA Astrophysics Data System (ADS)

    Poissant, Laurier; Casimir, Alain

    In order to evaluate and understand the processes of water-air and soil-air exchanges involved at background sites, an intensive field measurement campaign has been achieved during the summer of 1995 using high-time resolution techniques (10 min) at two sites (land and water) in southern Québec (Canada). Mercury flux was measured using a dynamic flux chamber technique coupled with an automatic mercury vapour-phase analyser (namely, Tekran®). The flux chamber shows that the rural grassy site acted primarily as a source of atmospheric mercury, its flux mimicked the solar radiation, with a maximum daytime value of ˜ 8.3 ng m -2 h -1 of TGM. The water surface location (St. Lawrence River site located about 3 km from the land site) shows deposition and evasion fluxes almost in the same order of magnitude (-0.5 vs 1.0 ng m -2 h -1).The latter is influenced to some extent by solar radiation but primarily by the formation of a layer of stable air over the water surface in which some redox reactions might promote evasion processes over the water surface. This process does not appear over the soil surface. As a whole, soil-air exchange rate is about 6-8 fold greater than the water-air exchange.

  12. Rapid wetland expansion during European settlement and its implication for marsh survival under modern sediment delivery rates

    USGS Publications Warehouse

    Kirwan, Matthew L.; Murray, A. Brad; Donnelly, Jeffrey P.; Corbett, D. Reide

    2011-01-01

    Fluctuations in sea-level rise rates are thought to dominate the formation and evolution of coastal wetlands. Here we demonstrate a contrasting scenario in which land-use-related changes in sediment delivery rates drive the formation of expansive marshland, and vegetation feedbacks maintain their morphology despite recent sediment supply reduction. Stratigraphic analysis and radiocarbon dating in the Plum Island Estuary (Massachusetts, United States) suggest that salt marshes expanded rapidly during the eighteenth and nineteenth centuries due to increased rates of sediment delivery following deforestation associated with European settlement. Numerical modeling coupled with the stratigraphic observations suggests that existing marshland could survive, but not form under the low suspended sediment concentrations observed in the estuary today. These results suggest that many of the expansive marshes that characterize the modern North American coast are metastable relicts of high nineteenth century sediment delivery rates, and that recent observations of degradation may represent a slow return to pre-settlement marsh extent. In contrast to ecosystem management practices in which restoring pre-anthropogenic conditions is seen as a way to increase ecosystem services, our results suggest that widespread efforts to restore valuable coastal wetlands actually prevent some systems from returning to a natural state.

  13. Air-water Gas Exchange Rates on a Large Impounded River Measured Using Floating Domes (Poster)

    EPA Science Inventory

    Mass balance models of dissolved gases in rivers typically serve as the basis for whole-system estimates of greenhouse gas emission rates. An important component of these models is the exchange of dissolved gases between air and water. Controls on gas exchange rates (K) have be...

  14. Association between Local Traffic-Generated Air Pollution and Preeclampsia and Preterm Delivery in the South Coast Air Basin of California

    PubMed Central

    Wu, Jun; Ren, Cizao; Delfino, Ralph J.; Chung, Judith; Wilhelm, Michelle; Ritz, Beate

    2009-01-01

    Background Preeclampsia is a major complication of pregnancy that can lead to substantial maternal and perinatal morbidity, mortality, and preterm birth. Increasing evidence suggests that air pollution adversely affects pregnancy outcomes. Yet few studies have examined how local traffic-generated emissions affect preeclampsia in addition to preterm birth. Objectives We examined effects of residential exposure to local traffic-generated air pollution on preeclampsia and preterm delivery (PTD). Methods We identified 81,186 singleton birth records from four hospitals (1997–2006) in Los Angeles and Orange Counties, California (USA). We used a line-source dispersion model (CALINE4) to estimate individual exposure to local traffic-generated nitrogen oxides (NOx) and particulate matter < 2.5 μm in aerodynamic diameter (PM2.5) across the entire pregnancy. We used logistic regression to estimate effects of air pollution exposures on preeclampsia, PTD (gestational age < 37 weeks), moderate PTD (MPTD; gestational age < 35 weeks), and very PTD (VPTD; gestational age < 30 weeks). Results We observed elevated risks for preeclampsia and preterm birth from maternal exposure to local traffic-generated NOx and PM2.5. The risk of preeclampsia increased 33% [odds ratio (OR) = 1.33; 95% confidence interval (CI), 1.18–1.49] and 42% (OR = 1.42; 95% CI, 1.26–1.59) for the highest NOx and PM2.5 exposure quartiles, respectively. The risk of VPTD increased 128% (OR = 2.28; 95% CI, 2.15–2.42) and 81% (OR = 1.81; 95% CI, 1.71–1.92) for women in the highest NOx and PM2.5 exposure quartiles, respectively. Conclusion Exposure to local traffic-generated air pollution during pregnancy increases the risk of preeclampsia and preterm birth in Southern California women. These results provide further evidence that air pollution is associated with adverse reproductive outcomes. PMID:20049131

  15. K{sub Air} and H*(10) Rate Constants for Gamma Emitters

    SciTech Connect

    Vega-Carrillo, H. R.; Juarez, R. Rodriguez; Manzanares-Acuna, E.; Davila, V. M. Hernandez; Mercado, G. A.

    2008-08-11

    Monte Carlo calculations have been carried out to estimate the Air Kerma rate constant and the Ambient dose equivalent rate constant for 139 monoenergetic photon sources. The factor that relates activity to air kerma rate or to ambient dose equivalent is useful to estimate the dose from a photon emitter source. Here 139 point-like and monoenergetic gamma-ray sources, ranging from 0.01 to 10 MeV were utilized in Monte Carlo calculations to estimate both gamma factors. These factors were utilized to calculate the air kerma-and-ambient dose equivalent rate constants for {sup 137}Cs-{sup 137m}Ba, {sup 198}Au, {sup 60}Co, and {sup 131}I, whose values were compared with those published in the literature.

  16. Entrainment Rate in Shallow Cumuli: Dependence on Entrained Dry Air Sources and Probability Density Functions

    NASA Astrophysics Data System (ADS)

    Lu, C.; Liu, Y.; Niu, S.; Vogelmann, A. M.

    2012-12-01

    In situ aircraft cumulus observations from the RACORO field campaign are used to estimate entrainment rate for individual clouds using a recently developed mixing fraction approach. The entrainment rate is computed based on the observed state of the cloud core and the state of the air that is laterally mixed into the cloud at its edge. The computed entrainment rate decreases when the air is entrained from increasing distance from the cloud core edge; this is because the air farther away from cloud edge is drier than the neighboring air that is within the humid shells around cumulus clouds. Probability density functions of entrainment rate are well fitted by lognormal distributions at different heights above cloud base for different dry air sources (i.e., different source distances from the cloud core edge). Such lognormal distribution functions are appropriate for inclusion into future entrainment rate parameterization in large scale models. To the authors' knowledge, this is the first time that probability density functions of entrainment rate have been obtained in shallow cumulus clouds based on in situ observations. The reason for the wide spread of entrainment rate is that the observed clouds are affected by entrainment mixing processes to different extents, which is verified by the relationships between the entrainment rate and cloud microphysics/dynamics. The entrainment rate is negatively correlated with liquid water content and cloud droplet number concentration due to the dilution and evaporation in entrainment mixing processes. The entrainment rate is positively correlated with relative dispersion (i.e., ratio of standard deviation to mean value) of liquid water content and droplet size distributions, consistent with the theoretical expectation that entrainment mixing processes are responsible for microphysics fluctuations and spectral broadening. The entrainment rate is negatively correlated with vertical velocity and dissipation rate because entrainment

  17. Zero-Order Antibiotic Release from Multilayer Contact Lenses: Nonuniform Drug and Diffusivity Distributions Produce Constant-Rate Drug Delivery.

    PubMed

    Guzman, Gustavo; Es-Haghi, Siamak Shams; Nugay, Turgut; Cakmak, Mukerrem

    2017-02-01

    A novel approach to zero-order constant-rate drug delivery from contact lenses is presented. Quasi-Case II non-Fickian transport is achieved by nonuniform drug and diffusivity distributions within three-layer bimodal amphiphilic conetworks (β-APCNs). The center layer is a highly oxygen permeable β-APCN matrix, which contains the drug and exhibits a high drug diffusivity. The outer β-APCN layers contain no-drug and are loaded with vitamin E, which slows diffusion. In contrast to single-layer neat-polymer and vitamin E-loaded films that display first-order "burst" kinetics, it is demonstrated experimentally and by modeling that the combined effect of nonuniform distribution of drug loading and diffusion constants within the three-layer lens maintains low local drug concentration at the lens-fluid interface and yields zero-order drug delivery. The release rates of topical antibiotics provide constant-rate therapeutic-level delivery with appropriate oxygen permeability for at least 30 h, at which time ≈25% of the drug was released.

  18. Time-delay when updating infusion rates in the Graseby 3400 pump results in reduced drug delivery.

    PubMed

    Sarraf, Elie; Mandel, Jeff E

    2014-01-01

    Infusion pumps are commonly used for infusion of drugs for physiologic control, and infusion rate has been demonstrated to affect the parameters of pharmacokinetic models. In attempting to develop a model that explained this behavior, we examined the behavior of the Graseby 3400 syringe pump under a range of flow conditions and with variations in syringe characteristics. Two issues were identified: start-up loss (the difference between actual and ideal delivery on initial infusion) and update loss (the difference between actual and ideal delivery when transmitting a command to change infusion rate). Under worst-case conditions, this may result in a 20-second period of zero delivery during start-up, and when updating infusion rates once per second, zero output. These effects are influenced by syringe characteristics and vary sufficiently as to make it impossible to isolate this effect from the pharmacokinetic process being controlled. The implications of this for previous published results and clinical application of target-controlled infusions are discussed.

  19. Integrating C-17 Direct Delivery Airlift into Traditional Air Force Doctrine.

    DTIC Science & Technology

    1998-06-01

    logistics response time, develop seamless logistic systems, and streamline the logistics infrastructure ( Zorich , 1996:2). The Air Force is moving from...and maintenance capability ( Zorich , 1996:2). Lean Logistics strives to produce a system in which logistics information and material flows freely...Air Mobility Warfare Center, March 1997. Zorich , David R. "Lean Logistics: Logistics of Tomorrow Today," A Special Report on Logistics for the 21st

  20. Cooling Rates of Humans in Air and in Water: An Experiment

    NASA Astrophysics Data System (ADS)

    Bohren, Craig F.

    2012-12-01

    In a previous article I analyzed in detail the physical factors resulting in greater cooling rates of objects in still water than in still air, emphasizing cooling of the human body. By cooling rate I mean the rate of decrease of core temperature uncompensated by metabolism. I concluded that the "correct ratio for humans is closer to 2 than to 10." To support this assertion I subsequently did experiments, which I report following a digression on hypothermia.

  1. The rate of pressure rise of gaseous propylene-air explosions in spherical and cylindrical enclosures.

    PubMed

    Razus, Domnina; Movileanua, Codina; Oancea, Dumitru

    2007-01-02

    The maximum rates of pressure rise of propylene-air explosions at various initial pressures and various fuel/oxygen ratios in three closed vessels (a spherical vessel with central ignition and two cylindrical vessels with central or with top ignition) are reported. It was found that in explosions of quiescent mixtures the maximum rates of pressure rise are linear functions on total initial pressure, at constant initial temperature and fuel/oxygen ratio. The slope and intercept of found correlations are greatly influenced by vessel's volume and shape and by the position of the ignition source--factors which determine the amount of heat losses from the burned gas in a closed vessel explosion. Similar data on propylene-air inert mixtures are discussed in comparison with those referring to propylene-air, revealing the influence of nature and amount of inert additive. The deflagration index KG of centrally ignited explosions was also calculated from maximum rates of pressure rise.

  2. Air pollutant emission rates for sources at the Deaf Smith County repository site

    SciTech Connect

    Not Available

    1985-11-01

    This document summarizes the air-quality source terms used for the Deaf Smith County, Texas environmental assessment report and explains their derivation. The engineering data supporting these source terms appear as appendixes to this report and include summary equipment lists for the repository and detailed equipment lists for the exploratory shaft. Although substantial work has been performed in establishing the current repository design, a greater effort will be required for the final design. Consequently, the repository emission rates presented here should be considered as preliminary estimates. Another set of air pollution emission rates will be calculated after design data are more firmly established. 18 refs., 15 tabs.

  3. EFFECT OF AIR-POLLUTION CONTROL ON DEATH RATES IN DUBLIN, IRELAND: AN INTERVENTION STUDY. (R827353C006)

    EPA Science Inventory

    Background Particulate air pollution episodes have been associated with increased daily death. However, there is little direct evidence that diminished particulate air pollution concentrations would lead to reductions in death rates. We assessed the effect of ...

  4. 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 ...

  5. Effects of saline-water flow rate and air speed on leakage current in RTV coatings

    SciTech Connect

    Kim, S.H.; Hackam, R.

    1995-10-01

    Room temperature vulcanizing (RTV) silicone rubber is increasingly being used to coat porcelain and glass insulators in order to improve their electrical performance in the presence of pollution and moisture. A study of the dependence of leakage current, pulse current count and total charge flowing across the surface of RTV on the flow rate of the saline water and on the compressed air pressure used to create the salt-fog is reported. The fog was directed at the insulating rods either from one or two sides. The RTV was fabricated from polydimethylsiloxane polymer, a filler of alumina trihydrate (ATH), a polymerization catalyst and fumed silica reinforcer, all dispersed in 1,1,1-trichloroethane solvent. The saline water flow rate was varied in the range 0.4 to 2.0 l/min. The compressed air pressure at the input of the fog nozzles was varied from 0.20 to 0.63 MPa. The air speed at the surface of the insulating rods was found to depend linearly on the air pressure measured at the inlet to the nozzles and varied in the range 3 to 14 km/hr. The leakage current increased with increasing flow rate and increasing air speed. This is attributed to the increased loss of hydrophobicity with a larger quantity of saline fog and a larger impact velocities of fog droplets interacting with the surface of the RTV coating.

  6. An Analysis of the Design-Build Delivery Approach in Air Force Military Construction

    DTIC Science & Technology

    2008-03-01

    Budget projects awarded NLT 31 Mar 06. Congressional Insert Projects FY06 Congressional Insert projects awarded NLT 30 Sep 06 CWE/PA Ratio The sum of the...Pacific Air Forces (PACAF) (2004). Automated Civil Engineer System Project Management (ACES-PM) Desktop Reference Manual. Conifer CO: OLA

  7. Contribution of climate and air pollution to variation in coronary heart disease mortality rates in England.

    PubMed

    Scarborough, Peter; Allender, Steven; Rayner, Mike; Goldacre, Michael

    2012-01-01

    There are substantial geographic variations in coronary heart disease (CHD) mortality rates in England that may in part be due to differences in climate and air pollution. An ecological cross-sectional multi-level analysis of male and female CHD mortality rates in all wards in England (1999-2004) was conducted to estimate the relative strength of the association between CHD mortality rates and three aspects of the physical environment--temperature, hours of sunshine and air quality. Models were adjusted for deprivation, an index measuring the healthiness of the lifestyle of populations, and urbanicity. In the fully adjusted model, air quality was not significantly associated with CHD mortality rates, but temperature and sunshine were both significantly negatively associated (p<0.05), suggesting that CHD mortality rates were higher in areas with lower average temperature and hours of sunshine. After adjustment for the unhealthy lifestyle of populations and deprivation, the climate variables explained at least 15% of large scale variation in CHD mortality rates. The results suggest that the climate has a small but significant independent association with CHD mortality rates in England.

  8. Contribution of Climate and Air Pollution to Variation in Coronary Heart Disease Mortality Rates in England

    PubMed Central

    Scarborough, Peter; Allender, Steven; Rayner, Mike; Goldacre, Michael

    2012-01-01

    There are substantial geographic variations in coronary heart disease (CHD) mortality rates in England that may in part be due to differences in climate and air pollution. An ecological cross-sectional multi-level analysis of male and female CHD mortality rates in all wards in England (1999–2004) was conducted to estimate the relative strength of the association between CHD mortality rates and three aspects of the physical environment - temperature, hours of sunshine and air quality. Models were adjusted for deprivation, an index measuring the healthiness of the lifestyle of populations, and urbanicity. In the fully adjusted model, air quality was not significantly associated with CHD mortality rates, but temperature and sunshine were both significantly negatively associated (p<0.05), suggesting that CHD mortality rates were higher in areas with lower average temperature and hours of sunshine. After adjustment for the unhealthy lifestyle of populations and deprivation, the climate variables explained at least 15% of large scale variation in CHD mortality rates. The results suggest that the climate has a small but significant independent association with CHD mortality rates in England. PMID:22427884

  9. Spray deposition inside tree canopies from a newly developed variable-rate air assisted sprayer

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Conventional spray applications in orchards and ornamental nurseries are not target-oriented, resulting in significant waste of pesticides and contamination of the environment. To address this problem, a variable-rate air-assisted sprayer implementing laser scanning technology was developed to apply...

  10. THE EFFECT OF OPENING WINDOWS ON AIR CHANGE RATES IN TWO HOMES

    EPA Science Inventory

    Over 300 air change rate experiments were completed in two occupied residences: a two-story detached house in Redwood City, CA and a three-story townhouse in Reston, VA. A continuous monitor was used to measure the decay of sulfur hexafluoride tracer gas over periods of 1 to 1...

  11. Structural Technology Evaluation and Analysis Program (STEAP). Delivery Order 0049: Computational Prototyping of Micro Air Vehicles

    DTIC Science & Technology

    2013-01-01

    integration at the system level . To quantitatively assess MAV technology, a more detailed engineering description is needed. 2 Approved for public...descriptions. A fairly unique source of system- level FWMAV data is the NATO AVT Task Group 184, “Characterization of Bio-Inspired Micro Air Vehicle...control geometric description utilizes the same underlying geometric description in the aerodynamics analysis, but adds an abstract level of describing

  12. Weather in the Cockpit: Priorities, Sources, Delivery, and Needs in the Next Generation Air Transportation System

    DTIC Science & Technology

    2012-07-01

    discomfort. Extreme turbulence could cause physical injuries to pilot/ passengers who are not wearing seat belts. Clear Air Turbulence (CAT) CAT... passengers who are not wearing seat belts. Generally caused by wind shear in the atmosphere where no clouds are present. Mountain Waves Fast...ways in which our analyses could inform the design of information systems. NextGen, in its mature state, envisions pilots having control over

  13. The effects of air pollutants on the mortality rate of lung cancer and leukemia.

    PubMed

    Dehghani, Mansooreh; Keshtgar, Laila; Javaheri, Mohammad Reza; Derakhshan, Zahra; Oliveri Conti, Gea; Zuccarello, Pietro; Ferrante, Margherita

    2017-03-24

    World Health Organization classifies air pollution as the first cause of human cancer. The present study investigated impact of air pollutants on the mortality rates of lung cancer and leukemia in Shiraz, one of the largests cities of Iran. This cross‑sectional (longitudinal) study was carried out in Shiraz. Data on six main pollutants, CO, SO2, O3, NO2, PM10 and PM2.5, were collected from Fars Environmental Protection Agency for 3,001 days starting from 1 January, 2005. Also, measures of climatic factors (temperature, humidity, and air pressure) were obtained from Shiraz Meteorological Organization. Finally, data related to number of deaths due to lung and blood cancers (leukemia) were gathered from Shiraz University Hospital. Relationship between variations of pollutant concentrations and cancers in lung and blood was investigated using statistical software R and MiniTab to perform time series analysis. Results of the present study revealed that the mortality rate of leukemia had a direct significant correlation with concentrations of nitrogen dioxide and carbon monoxide in the air (P<0.05). Therefore, special attention should be paid to sources of these pollutants and we need better management to decrease air pollutant concentrations through, e.g., using clean energy respect to fossil fuels, better management of urban traffic planning, and the improvement of public transport service and car sharing.

  14. Evaluation of the indoor air quality minimum ventilation rate procedure for use in California retail buildings.

    PubMed

    Dutton, S M; Mendell, M J; Chan, W R; Barrios, M; Sidheswaran, M A; Sullivan, D P; Eliseeva, E A; Fisk, W J

    2015-02-01

    This research assesses benefits of adding to California Title-24 ventilation rate (VR) standards a performance-based option, similar to the American Society of Heating, Refrigerating, and Air Conditioning Engineers 'Indoor Air Quality Procedure' (IAQP) for retail spaces. Ventilation rates and concentrations of contaminants of concern (CoC) were measured in 13 stores. Mass balance models were used to estimate 'IAQP-based' VRs that would maintain concentrations of all CoCs below health- or odor-based reference concentration limits. An intervention study in a 'big box' store assessed how the current VR, the Title 24-prescribed VR, and the IAQP-based VR (0.24, 0.69, and 1.51 air changes per hour) influenced measured IAQ and perceived of IAQ. Neither current VRs nor Title 24-prescribed VRs would maintain all CoCs below reference limits in 12 of 13 stores. In the big box store, the IAQP-based VR kept all CoCs below limits. More than 80% of subjects reported acceptable air quality at all three VRs. In 11 of 13 buildings, saving energy through lower VRs while maintaining acceptable IAQ would require source reduction or gas-phase air cleaning for CoCs. In only one of the 13 retail stores surveyed, application of the IAQP would have allowed reduced VRs without additional contaminant-reduction strategies.

  15. [Calculating method for the necessary lamps and sterile rate in a tube-shaped ultraviolet air washer].

    PubMed

    Xu, Z; Chen, C; Shen, J

    1998-05-01

    It has much more advantage to use the cylindric ultraviolet air washer than to use the ordinary ultraviolet lamps. There was a calculation method for determining necessary lamps in a rectangled ultraviolet air washer, but it had a limiting condition. This paper developed two calculating methods for determining necessary lamps and its sterile rate in a tube-shaped ultraviolet air washer. The sterile rate can be extracted with any parameter. Necessary lamps can also be extracted with its sterile rate.

  16. Relationship between recycling rate and air pollution: Waste management in the state of Massachusetts

    SciTech Connect

    Giovanis, Eleftherios

    2015-06-15

    Highlights: • This study examines the relationship between recycling rate of solid waste and air pollution. • Fixed effects Stochastic Frontier Analysis model with panel data are employed. • The case study is a waste municipality survey in the state of Massachusetts during 2009–2012. • The findings support that a negative relationship between air pollution and recycling. - Abstract: This study examines the relationship between recycling rate of solid waste and air pollution using data from a waste municipality survey in the state of Massachusetts during the period 2009–2012. Two econometric approaches are applied. The first approach is a fixed effects model, while the second is a Stochastic Frontier Analysis (SFA) with fixed effects model. The advantage of the first approach is the ability of controlling for stable time invariant characteristics of the municipalities, thereby eliminating potentially large sources of bias. The second approach is applied in order to estimate the technical efficiency and rank of each municipality accordingly. The regressions control for various demographic, economic and recycling services, such as income per capita, population density, unemployment, trash services, Pay-as-you-throw (PAYT) program and meteorological data. The findings support that a negative relationship between particulate particles in the air 2.5 μm or less in size (PM{sub 2.5}) and recycling rate is presented. In addition, the pollution is increased with increases on income per capita up to $23,000–$26,000, while after this point income contributes positively on air quality. Finally, based on the efficiency derived by the Stochastic Frontier Analysis (SFA) model, the municipalities which provide both drop off and curbside services for trash, food and yard waste and the PAYT program present better performance regarding the air quality.

  17. Effect of outside air ventilation rate on VOC concentrations and emissions in a call center

    SciTech Connect

    Hodgson, A.T.; Faulkner, D.; Sullivan, D.P.; DiBartolomeo, D.L.; Russell, M.L.; Fisk, W.J.

    2002-01-01

    A study of the relationship between outside air ventilation rate and concentrations of VOCs generated indoors was conducted in a call center. Ventilation rates were manipulated in the building's four air handling units (AHUs). Concentrations of VOCs in the AHU returns were measured on 7 days during a 13-week period. Indoor minus outdoor concentrations and emission factors were calculated. The emission factor data was subjected to principal component analysis to identify groups of co-varying compounds based on source type. One vector represented emissions of solvents from cleaning products. Another vector identified occupant sources. Direct relationships between ventilation rate and concentrations were not observed for most of the abundant VOCs. This result emphasizes the importance of source control measures for limiting VOC concentrations in buildings.

  18. Comparison of monoenergetic photon organ dose rate coefficients for stylized and voxel phantoms submerged in air

    SciTech Connect

    Bellamy, Michael B.; Hiller, Mauritius M.; Dewji, Shaheen A.; Veinot, Kenneth G.; Leggett, Richard Wayne; Eckerman, Keith F.; Easterly, Clay E.; Hertel, Nolan E.

    2016-02-01

    As part of a broader effort to calculate effective dose rate coefficients for external exposure to photons and electrons emitted by radionuclides distributed in air, soil or water, age-specific stylized phantoms have been employed to determine dose coefficients relating dose rate to organs and tissues in the body. In this article, dose rate coefficients computed using the International Commission on Radiological Protection reference adult male voxel phantom are compared with values computed using the Oak Ridge National Laboratory adult male stylized phantom in an air submersion exposure geometry. Monte Carlo calculations for both phantoms were performed for monoenergetic source photons in the range of 30 keV to 5 MeV. Furthermore, these calculations largely result in differences under 10 % for photon energies above 50 keV, and it can be expected that both models show comparable results for the environmental sources of radionuclides.

  19. Comparison of monoenergetic photon organ dose rate coefficients for stylized and voxel phantoms submerged in air

    DOE PAGES

    Bellamy, Michael B.; Hiller, Mauritius M.; Dewji, Shaheen A.; ...

    2016-02-01

    As part of a broader effort to calculate effective dose rate coefficients for external exposure to photons and electrons emitted by radionuclides distributed in air, soil or water, age-specific stylized phantoms have been employed to determine dose coefficients relating dose rate to organs and tissues in the body. In this article, dose rate coefficients computed using the International Commission on Radiological Protection reference adult male voxel phantom are compared with values computed using the Oak Ridge National Laboratory adult male stylized phantom in an air submersion exposure geometry. Monte Carlo calculations for both phantoms were performed for monoenergetic source photonsmore » in the range of 30 keV to 5 MeV. Furthermore, these calculations largely result in differences under 10 % for photon energies above 50 keV, and it can be expected that both models show comparable results for the environmental sources of radionuclides.« less

  20. Rate constants for chemical reactions in high-temperature nonequilibrium air

    NASA Technical Reports Server (NTRS)

    Jaffe, R. L.

    1986-01-01

    In the nonequilibrium atmospheric chemistry regime that will be encountered by the proposed Aeroassisted Orbital Transfer Vehicle in the upper atmosphere, where air density is too low for thermal and chemical equilibrium to be maintained, the detailed high temperature air chemistry plays a critical role in defining radiative and convective heating loads. Although vibrational and electronic temperatures remain low (less than 15,000 K), rotational and translational temperatures may reach 50,000 K. Attention is presently given to the effects of multiple temperatures on the magnitudes of various chemical reaction rate constants, for the cases of both bimolecular exchange reactions and collisional excitation and dissociation reactions.

  1. Association Between Air Temperature and Cancer Death Rates in Florida: An Ecological Study.

    PubMed

    Hart, John

    2015-01-01

    Proponents of global warming predict adverse events due to a slight warming of the planet in the last 100 years. This ecological study tests one of the possible arguments that might support the global warming theory - that it may increase cancer death rates. Thus, average daily air temperature is compared to cancer death rates at the county level in a U.S. state, while controlling for variables of smoking, race, and land elevation. The study revealed that lower cancer death rates were associated with warmer temperatures. Further study is indicated to verify these findings.

  2. Measurement of HOx• production rate due to radon decay in air

    SciTech Connect

    Ding, Huiling

    1993-08-01

    Radon in indoor air may cause the exposure of the public to excessive radioactivity. Radiolysis of water vapor in indoor air due to radon decay could produce (•OH and HO2 •) that may convert atmospheric constituents to compounds of lower vapor pressure. These lower vapor pressure compounds might then nucleate to form new particles in the indoor atmosphere. Chemical amplification was used to determine HOx• production rate in indoor air caused by radon decay. Average HOx• production rate was found to be (4.31±0.07) x 105 HOx• per Rn decay per second (Bq) 3.4 to 55.0% at 22C. This work provided G(HOx•)-value, 7.86±0.13 No./100 eV in air by directly measuring [HOx•] formed from the radiolysis procedure. This G value implies that HOx• produced by radon decay in air might be formed by multiple processes and may be result of positive ion-molecule reactions, primary radiolysis, and radical reactions. There is no obvious relation between HOx• production rate and relative humidity. A laser-induced fluorescence (LIF) system has been used for •OH production rate measurement; it consists of an excimer laser, a dye laser, a frequency doubler, a gaseous fluorescence chamber, and other optical and electronic parts. This system needs to be improved to eliminate the interferences of light scattering and artificial •OH produced from the photolysis of O3/H2O.

  3. Measuring Infiltration Rates in Homes as a Basis for Understanding Indoor Air Quality

    NASA Astrophysics Data System (ADS)

    Jerz, G. G.; Lamb, B. K.; Pressley, S. N.; O'Keeffe, P.; Fuchs, M.; Kirk, M.

    2015-12-01

    Infiltration rates, or the rate of air exchange, of houses are important to understand because ventilation can be a dominate factor in determining indoor air quality. There are chemicals that are emitted from surfaces or point sources inside the home which are harmful to humans; these chemicals come from various objects including furniture, cleaning supplies, building materials, gas stoves, and the surrounding environment. The use of proper ventilation to cycle cleaner outdoor air into the house can be crucial for maintaining healthy living conditions in the home. At the same time, there can also be outdoor pollutants which infiltrate the house and contribute to poor indoor air quality. In either case, it is important to determine infiltration rates as a function of outdoor weather conditions, the house structure properties and indoor heating and cooling systems. In this work, the objective is to measure ventilation rates using periodic releases of a tracer gas and measuring how quickly the tracer concentration decays. CO2 will be used as the tracer gas because it is inert and harmless at low levels. An Arduino timer is connected to a release valve which controls the release of 9.00 SLPM of CO2 into the uptake vent within the test home. CO2 will be released until there is at least a 200 to 300 ppm increase above ambient indoor levels. Computers with CO2 sensors and temperature/pressure sensors attached will be used to record data from different locations within the home which will continuously record data up to a week. The results from these periodic ventilation measurements will be analyzed with respect to outdoor wind and temperature conditions and house structure properties. The data will be used to evaluate an established indoor air quality model.

  4. Near-surface air temperature lapse rates in Xinjiang, northwestern China

    NASA Astrophysics Data System (ADS)

    Du, Mingxia; Zhang, Mingjun; Wang, Shengjie; Zhu, Xiaofan; Che, Yanjun

    2017-01-01

    Lapse rates of near-surface (2 m) air temperature are important parameters in hydrologic and climate simulations, especially for the mountainous areas without enough in-situ observations. In Xinjiang, northwestern China, the elevations range from higher than 7000 m to lower than sea level, but the existing long-term meteorological measurements are limited and distributed unevenly. To calculate lapse rates in Xinjiang, the daily data of near-surface air temperature (T min, T ave, and T max) were measured by automatic weather stations from 2012 to 2014. All the in situ observation stations were gridded into a network of 1.5° (latitude) by 1.5° (longitude), and the spatial distribution and the daily, monthly, seasonal variations of lapse rates for T min, T ave, and T max in Xinjiang are analyzed. The Urumqi River Basin has been considered as a case to study the influence of elevation, aspect, and the wet and dry air conditions to the T min, T ave, and T max lapse rates. Results show that (1) the lapse rates for T min, T ave, and T max vary spatially during the observation period. The spatial diversity of T min lapse rates is larger than that of T ave, and that of T max is the smallest. For each season, T max lapse rates have more negative values than T ave lapse rates which are steeper than T min lapse rates. The weakest spatial diversity usually appears in July throughout a year. (2) The comparison for the three subregions (North, Middle, and South region) exhibits that lapse rates have similar day-to-day and month-to-month characteristics which present shallower values in winter months and steeper values in summer months. The T ave lapse rates in North region are shallower than those in Middle and South region, and the steepest T ave lapse rates of the three regions all appear in April. T min lapse rates are shallower than T max lapse rates. The maximum medians of T min and T max lapse rates for each grid in the three regions all appear in January, whereas the

  5. Concentrations and decay rates of ozone in indoor air in dependence on building and surface materials.

    PubMed

    Moriske, H J; Ebert, G; Konieczny, L; Menk, G; Schöndube, M

    1998-08-01

    The decay of ozone in indoor air was measured in a closed chamber after contact with different building materials and residential surfaces. The tested materials were: vinyl wall paper, woodchip paper, plywood, latex paint, fitted carpet, and plaster. In the summer of 1996, the entry of ozone from ambient air into indoor air during ventilation and the ozone decay in indoor air, after windows had been closed again, were studied. Measurements were done in a residential house on the outskirts of Berlin. The following results were gained: the chamber measurements showed a decay of ozone after contact with most of the materials put inside the chamber. Higher decay rates have been obtained for wall papers, plywood, fitted carpet and plaster. As described in the literature, ozone is able to react with olefines inside the materials and is able to form formaldehyde and other components. This formation of formaldehyde could also be confirmed in our investigations. Thus, in most cases, the formaldehyde concentrations were lower than the German guideline value of 0.1 ppm. The formation of formaldehyde could be prevented when a special wall paper that was coated with activated carbon was used. In the house, a complete ozone diffusion into indoor air took place during ventilation within 30 min. After closing the windows, the ozone concentrations decreased to the basic level before ventilation within 60-90 min.

  6. US residential building air exchange rates: new perspectives to improve decision making at vapor intrusion sites.

    PubMed

    Reichman, Rivka; Shirazi, Elham; Colliver, Donald G; Pennell, Kelly G

    2017-02-22

    Vapor intrusion (VI) is well-known to be difficult to characterize because indoor air (IA) concentrations exhibit considerable temporal and spatial variability in homes throughout impacted communities. To overcome this and other limitations, most VI science has focused on subsurface processes; however there is a need to understand the role of aboveground processes, especially building operation, in the context of VI exposure risks. This tutorial review focuses on building air exchange rates (AERs) and provides a review of literature related building AERs to inform decision making at VI sites. Commonly referenced AER values used by VI regulators and practitioners do not account for the variability in AER values that have been published in indoor air quality studies. The information presented herein highlights that seasonal differences, short-term weather conditions, home age and air conditioning status, which are well known to influence AERs, are also likely to influence IA concentrations at VI sites. Results of a 3D VI model in combination with relevant AER values reveal that IA concentrations can vary more than one order of magnitude due to air conditioning status and one order of magnitude due to house age. Collectively, the data presented strongly support the need to consider AERs when making decisions at VI sites.

  7. Smoking, air pollution, and the high rates of lung cancer in Shenyang, China

    SciTech Connect

    Xu, Z.Y.; Blot, W.J.; Xiao, H.P.; Wu, A.; Feng, Y.P.; Stone, B.J.; Sun, J.; Ershow, A.G.; Henderson, B.E.; Fraumeni, J.F. Jr. )

    1989-12-06

    A case-control study involving interviews with 1,249 patients with lung cancer and 1,345 population-based controls was conducted in Shenyang, an industrial city in northeastern China, where mortality rates are high among men and women. Cigarette smoking was found to be the principal cause of lung cancer in this population, accounting for 55% of the lung cancers in males and 37% in females. The attributable risk percentage among females is high compared to elsewhere in China, largely because of a higher prevalence of smoking among women. After adjustment for smoking, there were also significant increases in lung cancer risk associated with several measures of exposure to air pollutants. Risks were twice as high among those who reported smoky outdoor environments, and increased in proportion to years of sleeping on beds heated by coal-burning stoves (kang), and to an overall index of indoor air pollution. Threefold increases in lung cancer risk were found among men who worked in the nonferrous smelting industry, where heavy exposures to inorganic arsenic have been reported. The associations with both smoking and indoor air pollution were stronger for squamous cell and small cell carcinomas than for adenocarcinoma of the lung. Risks due to smoking or air pollution were not greatly altered by adjustment for consumption of fresh vegetables or sources of beta carotene or retinol, prior chronic lung diseases, or education level. The findings suggest that smoking and environmental pollution combine to account for the elevated rates of lung cancer mortality in Shenyang.

  8. Effect of laminar air flow and clean-room dress on contamination rates of intravenous admixtures.

    PubMed

    Brier, K L; Latiolais, C J; Schneider, P J; Moore, T D; Buesching, W J; Wentworth, B C

    1981-08-01

    The effect of laminar air flow conditions and clean-room dress on the microbial contamination rates of intravenous admixtures was investigated. Intravenous admixtures were prepared by one investigator using aseptic technique under four environmental conditions: laminar air flow conditions with clean-room dress; laminar air flow without clean-room dress; clean table top with clean-room dress; and clean table top without clean-room dress. In each environmental condition, 350 admixtures were compounded. Negative-control samples (n = 150) were also tested, as were 10 positive-control samples. Samples were tested in each of two growth media and incubated at 35 degrees C for 14 days or until growth occurred. The incidence of contamination of admixtures compounded in laminar air flow conditions was significantly less than the contamination of those compounded on a clean table top (p less than 0.05) regardless of the operator's dress. The incidence of contamination of admixtures compounded while wearing clean-room dress was not significantly different from those prepared while not wearing clean-room dress regardless of the environment in which the admixture was prepared. The overall low level of contamination [0.79% (11/1400)] was inconclusive regarding the effect of dress on the incidence of contamination when admixtures were prepared under LAF conditions. It is concluded that, when one adheres to aseptic technique, the environment in which admixtures are compounded is the most important variable affecting the microbial contamination rate.

  9. Relationship between recycling rate and air pollution: Waste management in the state of Massachusetts.

    PubMed

    Giovanis, Eleftherios

    2015-06-01

    This study examines the relationship between recycling rate of solid waste and air pollution using data from a waste municipality survey in the state of Massachusetts during the period 2009-2012. Two econometric approaches are applied. The first approach is a fixed effects model, while the second is a Stochastic Frontier Analysis (SFA) with fixed effects model. The advantage of the first approach is the ability of controlling for stable time invariant characteristics of the municipalities, thereby eliminating potentially large sources of bias. The second approach is applied in order to estimate the technical efficiency and rank of each municipality accordingly. The regressions control for various demographic, economic and recycling services, such as income per capita, population density, unemployment, trash services, Pay-as-you-throw (PAYT) program and meteorological data. The findings support that a negative relationship between particulate particles in the air 2.5 μm or less in size (PM2.5) and recycling rate is presented. In addition, the pollution is increased with increases on income per capita up to $23,000-$26,000, while after this point income contributes positively on air quality. Finally, based on the efficiency derived by the Stochastic Frontier Analysis (SFA) model, the municipalities which provide both drop off and curbside services for trash, food and yard waste and the PAYT program present better performance regarding the air quality.

  10. Impact of small MU/segment and dose rate on delivery accuracy of volumetric-modulated arc therapy (VMAT).

    PubMed

    Huang, Long; Zhuang, Tingliang; Mastroianni, Anthony; Djemil, Toufik; Cui, Taoran; Xia, Ping

    2016-05-01

    Volumetric-modulated arc therapy (VMAT) plans may require more control points (or segments) than some of fixed-beam IMRT plans that are created with a limited number of segments. Increasing number of control points in a VMAT plan for a given prescription dose could create a large portion of the total number of segments with small number monitor units (MUs) per segment. The purpose of this study is to investigate the impact of the small number MU/segment on the delivery accuracy of VMAT delivered with various dose rates. Ten patient datasets were planned for hippocampus sparing for whole brain irradiation. For each dataset, two VMAT plans were created with maximum dose rates of 600 MU/min (the maximum field size of 21×40 cm2) and 1000 MU/min (the maximum field size of 15×15 cm2) for a daily dose of 3 Gy. Without reoptimization, the daily dose of these plans was purposely reduced to 1.5 Gy and 1.0 Gy while keeping the same total dose. Using the two dose rates and three different daily doses, six VMAT plans for each dataset were delivered to a physical phantom to investigate how the changes of dose rate and daily doses impact on delivery accuracy. Using the gamma index, we directly compared the delivered planar dose profiles with the reduced daily doses (1.5 Gy and 1.0 Gy) to the delivered planar dose at 3 Gy daily dose, delivered at dose rate of 600 MU/min and 1000 MU/min, respectively. The average numbers of segments with MU/segment≤1 were 35±8, 87±6 for VMAT-600 1.5 Gy, VMAT-600 1 Gy plans, and 30±7 and 42±6 for VMAT-1000 1.5 Gy and VMAT-1000 1 Gy plans, respectively. When delivered at 600 MU/min dose rate, the average gamma index passing rates (1%/1 mm criteria) of comparing delivered 1.5 Gy VMAT planar dose profiles to 3.0 Gy VMAT delivered planar dose profiles was 98.28%±1.66%, and the average gamma index passing rate of comparing delivered 1.0 Gy VMAT planar dose to 3.0 Gy VMAT delivered planar dose was 83.75%±4.86%. If using 2%/2 mm and 3%/3 mm

  11. Impact of small MU/segment and dose rate on delivery accuracy of volumetric-modulated arc therapy (VMAT).

    PubMed

    Huang, Long; Zhuang, Tingliang; Mastroianni, Anthony; Djemil, Toufik; Cui, Taoran; Xia, Ping

    2016-05-08

    Volumetric-modulated arc therapy (VMAT) plans may require more control points (or segments) than some of fixed-beam IMRT plans that are created with a limited number of segments. Increasing number of control points in a VMAT plan for a given prescription dose could create a large portion of the total number of segments with small number monitor units (MUs) per segment. The purpose of this study is to investigate the impact of the small number MU/segment on the delivery accuracy of VMAT delivered with various dose rates. Ten patient datasets were planned for hippocampus sparing for whole brain irradiation. For each dataset, two VMAT plans were created with maximum dose rates of 600 MU/min (the maximum field size of 21 × 40 cm2) and 1000 MU/min (the maximum field size of 15 × 15 cm2) for a daily dose of 3 Gy. Without reoptimization, the daily dose of these plans was purposely reduced to 1.5 Gy and 1.0 Gy while keeping the same total dose. Using the two dose rates and three different daily doses, six VMAT plans for each dataset were delivered to a physical phantom to investigate how the changes of dose rate and daily doses impact on delivery accuracy. Using the gamma index, we directly compared the delivered planar dose profiles with the reduced daily doses (1.5 Gy and 1.0 Gy) to the delivered planar dose at 3 Gy daily dose, delivered at dose rate of 600 MU/min and 1000 MU/min, respectively. The average numbers of segments with MU/segment ≤ 1 were 35 ± 8, 87 ± 6 for VMAT-600 1.5 Gy, VMAT-600 1 Gy plans, and 30 ± 7 and 42 ± 6 for VMAT-1000 1.5 Gy and VMAT-1000 1 Gy plans, respectively. When delivered at 600 MU/min dose rate, the average gamma index passing rates (1%/1 mm criteria) of comparing delivered 1.5 Gy VMAT planar dose profiles to 3.0 Gy VMAT delivered planar dose profiles was 98.28% ± 1.66%, and the average gamma index passing rate of comparing delivered 1.0 Gy VMAT planar dose to 3.0 Gy VMAT delivered planar dose was 83.75% ± 4.86%. If using 2%/2mm

  12. Effective Dose Rate Coefficients for Immersions in Radioactive Air and Water.

    PubMed

    Bellamy, M B; Veinot, K G; Hiller, M M; Dewji, S A; Eckerman, K F; Easterly, C E; Hertel, N E; Leggett, R W

    2016-05-05

    The Oak Ridge National Laboratory Center for Radiation Protection Knowledge (CRPK) has undertaken a number of calculations in support of a revision to the United States Environmental Protection Agency (US EPA) Federal Guidance Report on external exposure to radionuclides in air, water and soil (FGR 12). Age-specific mathematical phantom calculations were performed for the conditions of submersion in radioactive air and immersion in water. Dose rate coefficients were calculated for discrete photon and electron energies and folded with emissions from 1252 radionuclides using ICRP Publication 107 decay data to determine equivalent and effective dose rate coefficients. The coefficients calculated in this work compare favorably to those reported in FGR12 as well as by other authors that employed voxel phantoms for similar exposure scenarios.

  13. Mathematical Modeling of Radiocesium Migration and Air Dose Rate Changes in Eastern Fukushima Prefecture

    NASA Astrophysics Data System (ADS)

    Kitamura, A.; Sakuma, K.; Kurikami, H.; Malins, A.; Okumura, M.; Itakura, M.; Yamada, S.; Machida, M.

    2015-12-01

    Radioactive cesium that was deposited over Fukushima Prefecture after the accident at the Fukushima Daiichi nuclear power plant station is one of the major concerns regarding health physics today. Its migration is primarily by soil erosion and sediment transport within surface water during times of heavy rainfall and flooding. In order to predict the future distribution of radioactive cesium and resulting air dose rate at any location in Fukushima, we have integrated a number of mathematical models covering different time and spatial scales. In this presentation we report our overall scheme of prediction starting from sediment and radioactive cesium movement and resulting long term air dose rate changes. Specifically, we present simulation results of sediment movement and radioactive cesium migration using semi-empirical and physics based watershed models, and that of sediment and radioactive cesium behavior in a dam reservoir using one and two dimensional river simulation models. The model's results are compared with ongoing field monitoring.

  14. Effects of aluminum-copper alloy filtration on photon spectra, air kerma rate and image contrast.

    PubMed

    Gonçalves, Andréa; Rollo, João Manuel Domingos de Almeida; Gonçalves, Marcelo; Haiter Neto, Francisco; Bóscolo, Frab Norberto

    2004-01-01

    This study evaluated the performance of aluminum-copper alloy filtration, without the original aluminum filter, for dental radiography in terms of x-ray energy spectrum, air kerma rate and image quality. Comparisons of various thicknesses of aluminum-copper alloy in three different percentages were made with aluminum filtration. Tests were conducted on an intra-oral dental x-ray machine and were made on mandible phantom and on step-wedge. Depending on the thickness of aluminum-copper alloy filtration, the beam could be hardened and filtrated. The use of the aluminum-copper alloy filter resulted in reductions in air kerma rate from 8.40% to 47.33%, and indicated the same image contrast when compared to aluminum filtration. Aluminum-copper alloy filtration may be considered a good alternative to aluminum filtration.

  15. An Extended EPQ-Based Problem with a Discontinuous Delivery Policy, Scrap Rate, and Random Breakdown

    PubMed Central

    Song, Ming-Syuan; Chen, Hsin-Mei; Chiu, Yuan-Shyi P.

    2015-01-01

    In real supply chain environments, the discontinuous multidelivery policy is often used when finished products need to be transported to retailers or customers outside the production units. To address this real-life production-shipment situation, this study extends recent work using an economic production quantity- (EPQ-) based inventory model with a continuous inventory issuing policy, defective items, and machine breakdown by incorporating a multiple delivery policy into the model to replace the continuous policy and investigates the effect on the optimal run time decision for this specific EPQ model. Next, we further expand the scope of the problem to combine the retailer's stock holding cost into our study. This enhanced EPQ-based model can be used to reflect the situation found in contemporary manufacturing firms in which finished products are delivered to the producer's own retail stores and stocked there for sale. A second model is developed and studied. With the help of mathematical modeling and optimization techniques, the optimal run times that minimize the expected total system costs comprising costs incurred in production units, transportation, and retail stores are derived, for both models. Numerical examples are provided to demonstrate the applicability of our research results. PMID:25821853

  16. An extended EPQ-based problem with a discontinuous delivery policy, scrap rate, and random breakdown.

    PubMed

    Chiu, Singa Wang; Lin, Hong-Dar; Song, Ming-Syuan; Chen, Hsin-Mei; Chiu, Yuan-Shyi P

    2015-01-01

    In real supply chain environments, the discontinuous multidelivery policy is often used when finished products need to be transported to retailers or customers outside the production units. To address this real-life production-shipment situation, this study extends recent work using an economic production quantity- (EPQ-) based inventory model with a continuous inventory issuing policy, defective items, and machine breakdown by incorporating a multiple delivery policy into the model to replace the continuous policy and investigates the effect on the optimal run time decision for this specific EPQ model. Next, we further expand the scope of the problem to combine the retailer's stock holding cost into our study. This enhanced EPQ-based model can be used to reflect the situation found in contemporary manufacturing firms in which finished products are delivered to the producer's own retail stores and stocked there for sale. A second model is developed and studied. With the help of mathematical modeling and optimization techniques, the optimal run times that minimize the expected total system costs comprising costs incurred in production units, transportation, and retail stores are derived, for both models. Numerical examples are provided to demonstrate the applicability of our research results.

  17. Air bubble migration rates as a proxy for bubble pressure distribution in ice cores

    NASA Astrophysics Data System (ADS)

    Dadic, Ruzica; Schneebeli, Martin; Bertler, Nancy

    2015-04-01

    Air bubble migration can be used as a proxy to measure the pressure of individual bubbles and can help constrain the gradual close-off of gas bubbles and the resulting age distribution of gases in ice cores. The close-off depth of single bubbles can vary by tens of meters, which leads to a distribution of pressures for bubbles at a given depth. The age distribution of gases (along with gas-age-ice-age differences) decreases the resolution of the gas level reconstructions from ice cores and limits our ability to determine the phase relationship between gas and ice, and thus, the impact of rapid changes of greenhouse gases on surface temperatures. For times of rapid climate change, including the last 150 years, and abrupt climate changes further back in the past, knowledge of the age distribution of the gases trapped in air bubbles will enable us to refine estimates of atmospheric changes. When a temperature gradient is applied to gas bubbles in an ice sample, the bubbles migrate toward warmer ice. This motion is caused by sublimation from the warm wall and subsequent frost deposition on the cold wall. The migration rate depends on ice temperature and bubble pressure and is proportional to the temperature gradient. The spread in migration rates for bubbles in the same samples at given temperatures should therefore reflect the variations in bubble pressures within a sample. Air bubbles with higher pressures would have been closed off higher in the firn column and thus have had time to equilibrate with the surrounding ice pressure, while air bubbles that have been closed off recently would have pressures that are similar to todays atmospheric pressure above the firn column. For ice under pressures up to ~13-16 bar, the pressure distribution of bubbles from a single depth provides a record of the trapping function of air bubbles in the firn column for a certain time in the past. We will present laboratory experiments on air bubble migration, using Antarctic ice core

  18. Schedule-induced drinking: rate of food delivery and Herrnstein's equation.

    PubMed Central

    Wetherington, C L

    1979-01-01

    Schedule-induced drinking was measured in four rats exposed to fixed-time schedules of food ranging from 30 to 480 seconds. Herrnstein's (1970, 1974) equation relating rate of a single response as a hyperbolic function of reinforcement rate provided a good fit to three measures of drinking: lick rate, ingestion rate, and relative time spent drinking. The functions relating the three measures of drinking to reinforcement rate were of similar form. Herrnstein's equation also provided a good description of some already published data on schedule-induced drinking. The fit both to the present data and to the already published data was improved somewhat by computing the measures by subtracting from the time base a latency constant representing the minimal time required to consume the food pellet and travel to the water source. The data from this study provide two correspondences between operant behavior and schedule-induced behavior: (a) conformity to Herrnstein's equation and (b) equivalence of rate and relative time measures. PMID:512568

  19. Determination of collisional quenching rate coefficients of metastable nitrogen molecules by air pollutants

    NASA Astrophysics Data System (ADS)

    Suzuki, Susumu; Itoh, Haruo

    2009-10-01

    It has already been investigated on the determination of the collisional quenching rate coefficients of the metastable nitrogen molecules N2(A^3σu^+ ) by some air pollutants [1] in our laboratory. In this report, we present the result on the collisional quenching rate coefficient of N2(A^3σu^+ ) by formaldehyde (CH2O) using a theoretical procedure that takes into account the reflection of metastables at the boundary. As far as we know, this report is the first result of the collisional quenching rate coefficients of N2(A^3σu^+ ) by CH2O. Formaldehyde is a colorless gas with the foul odor, and elements of the adhesive, paints, and preservative, etc. It is widely used for construction materials such as houses, because it is low cost. It is released from paint of construction materials in air, and, in that case, it is known as one of the causative agents of so-called ``Sick building syndrome'' to influence the human body harmfully even if it is a low concentration. The obtained collisional quenching rate coefficient of N2(A^3σu^+ ) by CH2O is (4.7±0.4) x 10-12 cm^3/s. Because the collisional quenching rate coefficient by CH2O is large, it is understood that CH2O receives energy easily from N2(A^3σu^+ ). In addition, we reports on the obtained collisional quenching rate coefficient of N2(A^3σu^+ ) by some air pollutants. [1] S. Suzuki, T.Suzuki and H.Itoh: Proc. of XXVIII ICPIG (Prague, Czech Republic), (2007) 1P01-40.

  20. Air-to-Water Heat Pumps With Radiant Delivery in Low-Load Homes

    SciTech Connect

    Backman, C.; German, A.; Dakin, B.; Springer, D.

    2013-12-01

    Space conditioning represents nearly 50% of average residential household energy consumption, highlighting the need to identify alternative cost-effective, energy-efficient cooling and heating strategies. As homes are better built, there is an increasing need for strategies that are particularly well suited for high performance, low load homes. ARBI researchers worked with two test homes in hot-dry climates to evaluate the in-situ performance of air-to-water heat pump (AWHP) systems, an energy efficient space conditioning solution designed to cost-effectively provide comfort in homes with efficient, safe, and durable operation. Two monitoring projects of test houses in hot-dry climates were initiated in 2010 to test this system. Both systems were fully instrumented and have been monitored over one year to capture complete performance data over the cooling and heating seasons. Results are used to quantify energy savings, cost-effectiveness, and system performance using different operating modes and strategies. A calibrated TRNSYS model was developed and used to evaluate performance in various climate regions. This strategy is most effective in tight, insulated homes with high levels of thermal mass (i.e. exposed slab floors).

  1. Air-to-Water Heat Pumps With Radiant Delivery in Low-Load Homes

    SciTech Connect

    Backman, C.; German, A.; Dakin, B.; Springer, D.

    2013-12-01

    Space conditioning represents nearly 50% of average residential household energy consumption, highlighting the need to identify alternative cost-effective, energy-efficient cooling and heating strategies. As homes are better built, there is an increasing need for strategies that are particularly well suited for high performance, low load homes. ARBI researchers worked with two test homes in hot-dry climates to evaluate the in-situ performance of air-to-water heat pump systems, an energy efficient space conditioning solution designed to cost-effectively provide comfort in homes with efficient, safe, and durable operation. Two monitoring projects of test houses in hot-dry climates were initiated in 2010 to test this system. Both systems were fully instrumented and have been monitored over one year to capture complete performance data over the cooling and heating seasons. Results are used to quantify energy savings, cost-effectiveness, and system performance using different operating modes and strategies. A calibrated TRNSYS model was developed and used to evaluate performance in various climate regions. This strategy is most effective in tight, insulated homes with high levels of thermal mass (i.e. exposed slab floors).

  2. Impact of Obstetrician/Gynecologist Hospitalists on Quality of Obstetric Care (Cesarean Delivery Rates, Trial of Labor After Cesarean/Vaginal Birth After Cesarean Rates, and Neonatal Adverse Events).

    PubMed

    Iriye, Brian K

    2015-09-01

    Care via obstetric hospitalists continues to expand, quickly becoming an integral part of labor and delivery management in urban and suburban areas. Overall lower cesarean delivery rates have been found with obstetric hospitalist care. Continuous 24-hour coverage of labor units has displayed lower rates of neonatal adverse events and likely reduces time in decision to delivery. Further study is needed on maternal and neonatal outcomes to corroborate earlier observations, and to closely examine the type of obstetric hospitalist model being observed to aid in planning the ideal deployment of providers in this workforce of the future.

  3. Effects of Stream Channel Characteristics on Nitrate Delivery to Streams and In-Stream Denitrification Rates, Raccoon River, Iowa

    NASA Astrophysics Data System (ADS)

    Prestegaard, K. L.; O'Connell, M.

    2004-05-01

    Streams in agricultural areas often exhibit significant channel and sediment modifications; they are often incised and transport more fine sediment than non-agricultural streams. These channel characteristics can influence stream water quality by modifying surface-groundwater interactions. In the Raccoon River basin, channel incision increases the delivery of nitrate from the groundwater to the streams. The sandy in-stream sediments, however, serve as very effective sites for in-stream denitrification. Nitrate delivery and in-stream denitrification was examined in 3 subwatersheds of the Raccoon River. Stream morphology, water quality, and sediment characteristics were measured at 35 sites with varying land uses. Headwater stream nitrate concentration increased with percent row crops and the amount of channel incision. Downstream sites showed a wide variation in nitrate concentration with land use. Stream nitrate concentrations were measured at 6 sites in each of 3 streams with high percentages of row crop land uses during high summer baseflow following the 1993 floods and during average summer baseflow in 1995. Nitrate concentrations were systematically higher for the high baseflow conditions of 1993 than the average year (1995). This change in nitrate concentration is interpreted as the increased effectiveness of nitrate delivery to the stream during periods of high water tables. The effect was most pronounced in incised reaches. All 3 streams show downstream decreases in nitrate concentration. Water samples for all the sites in the watersheds were analyzed for nitrogen isotopic composition. The nitrogen isotopic composition shifts with towards higher d 15N values with decreasing nitrate concentration. This is consistent with denitrification reactions that selectively remove the 14N leaving a higher proportion of 15N in the nitrate. This suggests that most of the downstream decrease in nitrate concentrations is a result of in-stream denitrification. The high rates

  4. A bench evaluation of fraction of oxygen in air delivery and tidal volume accuracy in home care ventilators available for hospital use

    PubMed Central

    Baboi, Loredana; Subtil, Fabien

    2016-01-01

    Background Turbine-powered ventilators are not only designed for long-term ventilation at home but also for hospital use. It is important to verify their capabilities in delivering fraction of oxygen in air (FIO2) and tidal volume (VT). Methods We assessed the FIO2 accuracy and the VT delivery in four home care ventilators (HCV) on the bench. The four HCV were Astral 150, Elisée 150, Monnal T50 and Trilogy 200 HCV, which were connected to a lung model (ASL 5000). For assessing FIO2 accuracy, lung model was set to mimic an obstructive lung and HCV were set in volume controlled mode (VC). They supplied with air, 3 or 15 L/min oxygen and FIO2 was measured by using a ventilator tester (Citrex H4TM). For the VT accuracy, the lung model was set in a way to mimic three adult configurations (normal, obstructive, or restrictive respiratory disorder) and one pediatric configuration. Each HCV was set in VC. Two VT (300 and 500 mL) in adult lung configuration and one 50 mL VT in pediatric lung configuration, at two positive end expiratory pressures 5 and 10 cmH2O, were tested. VT accuracy was measured as volume error (the relative difference between set and measured VT). Statistical analysis was performed by suing one-factor ANOVA with a Bonferroni correction for multiple tests. Results For Astral 150, Elisée 150, Monnal T50 and Trilogy 200, FIO2 averaged 99.2%, 93.7%, 86.3%, and 62.1%, respectively, at 15 L/min oxygen supplementation rate (P<0.001). Volume error was 0.5%±0%, −38%±0%, −9%±0%, −29%±0% and −36%±0% for pediatric lung condition (P<0.001). In adult lung configurations, Monnal T50 systematically over delivered VT and Trilogy 150 was sensitive to lung configuration when VT was set to 300 mL at either positive end-expiratory pressure (PEEP). Conclusions HCV are different in terms of FIO2 efficiency and VT delivery. PMID:28149559

  5. The Tip of the Tail Needle Affects the Rate of DNA Delivery by Bacteriophage P22

    PubMed Central

    Leavitt, Justin C.; Gogokhia, Lasha; Gilcrease, Eddie B.; Bhardwaj, Anshul; Cingolani, Gino; Casjens, Sherwood R.

    2013-01-01

    The P22-like bacteriophages have short tails. Their virions bind to their polysaccharide receptors through six trimeric tailspike proteins that surround the tail tip. These short tails also have a trimeric needle protein that extends beyond the tailspikes from the center of the tail tip, in a position that suggests that it should make first contact with the host’s outer membrane during the infection process. The base of the needle serves as a plug that keeps the DNA in the virion, but role of the needle during adsorption and DNA injection is not well understood. Among the P22-like phages are needle types with two completely different C-terminal distal tip domains. In the phage Sf6-type needle, unlike the other P22-type needle, the distal tip folds into a “knob” with a TNF-like fold, similar to the fiber knobs of bacteriophage PRD1 and Adenovirus. The phage HS1 knob is very similar to that of Sf6, and we report here its crystal structure which, like the Sf6 knob, contains three bound L-glutamate molecules. A chimeric P22 phage with a tail needle that contains the HS1 terminal knob efficiently infects the P22 host, Salmonella enterica, suggesting the knob does not confer host specificity. Likewise, mutations that should abrogate the binding of L-glutamate to the needle do not appear to affect virion function, but several different other genetic changes to the tip of the needle slow down potassium release from the host during infection. These findings suggest that the needle plays a role in phage P22 DNA delivery by controlling the kinetics of DNA ejection into the host. PMID:23951045

  6. Chemical response of methane/air diffusion flames to unsteady strain rate

    SciTech Connect

    Im, H.G.; Chen, J.H.; Chen, J.Y.

    1998-03-01

    Effects of unsteady strain rate on the response of methane/air diffusion flames are studied. The authors use the finite-domain opposed flow configuration in which the nozzle exit velocity is imposed as a function of time. The GRI mechanism v2.11 is used for the detailed methane/air chemistry. The response of individual species to monochromatic oscillation in strain rate with various frequencies reveals that the fluctuation of slow species, such as CO and NO{sub x}, is more rapidly suppressed as the flow time scale decreases. It is also observed that the maximum CO concentration is very insensitive to the variation in the scalar dissipation rate. An extinction event due to an abrupt imposition of high strain rates is also simulated by an impulsive velocity with various frequencies. For a fast impulse, a substantial overshoot in NO{sub 2} concentration is observed after extinction. Finally, the overall fuel burning rate shows a nonmonotonic response to the variation in characteristic unsteady time scale, while the emission indices for NO{sub x} shows monotonic decay in response as frequency is increased.

  7. Avoidance of Timeout from Response-Independent Food: Effects of Delivery Rate and Quality

    ERIC Educational Resources Information Center

    Richardson, Joseph V.; Baron, Alan

    2008-01-01

    In three experiments, a rat's lever presses could postpone timeouts from food pellets delivered on response-independent schedules. In Experiment 1, the pellets were delivered at variable-time (VT) rates ranging from VT 0.5 to VT 8 min. Experiment 2 replicated the VT 1 min and VT 8 min conditions of Experiment 1 with new subjects. Finally, subjects…

  8. Predicting Residential Air Exchange Rates from Questionnaires and Meteorology: Model Evaluation in Central North Carolina

    PubMed Central

    2010-01-01

    A critical aspect of air pollution exposure models is the estimation of the air exchange rate (AER) of individual homes, where people spend most of their time. The AER, which is the airflow into and out of a building, is a primary mechanism for entry of outdoor air pollutants and removal of indoor source emissions. The mechanistic Lawrence Berkeley Laboratory (LBL) AER model was linked to a leakage area model to predict AER from questionnaires and meteorology. The LBL model was also extended to include natural ventilation (LBLX). Using literature-reported parameter values, AER predictions from LBL and LBLX models were compared to data from 642 daily AER measurements across 31 detached homes in central North Carolina, with corresponding questionnaires and meteorological observations. Data was collected on seven consecutive days during each of four consecutive seasons. For the individual model-predicted and measured AER, the median absolute difference was 43% (0.17 h−1) and 40% (0.17 h−1) for the LBL and LBLX models, respectively. Additionally, a literature-reported empirical scale factor (SF) AER model was evaluated, which showed a median absolute difference of 50% (0.25 h−1). The capability of the LBL, LBLX, and SF models could help reduce the AER uncertainty in air pollution exposure models used to develop exposure metrics for health studies. PMID:21069949

  9. Air exchange rates and migration of VOCs in basements and residences

    PubMed Central

    Du, Liuliu; Batterman, Stuart; Godwin, Christopher; Rowe, Zachary; Chin, Jo-Yu

    2015-01-01

    Basements can influence indoor air quality by affecting air exchange rates (AERs) and by the presence of emission sources of volatile organic compounds (VOCs) and other pollutants. We characterized VOC levels, AERs and interzonal flows between basements and occupied spaces in 74 residences in Detroit, Michigan. Flows were measured using a steady-state multi-tracer system, and 7-day VOC measurements were collected using passive samplers in both living areas and basements. A walkthrough survey/inspection was conducted in each residence. AERs in residences and basements averaged 0.51 and 1.52 h−1, respectively, and had strong and opposite seasonal trends, e.g., AERs were highest in residences during the summer, and highest in basements during the winter. Air flows from basements to occupied spaces also varied seasonally. VOC concentration distributions were right-skewed, e.g., 90th percentile benzene, toluene, naphthalene and limonene concentrations were 4.0, 19.1, 20.3 and 51.0 μg m−3, respectively; maximum concentrations were 54, 888, 1117 and 134 μg m−3. Identified VOC sources in basements included solvents, household cleaners, air fresheners, smoking, and gasoline-powered equipment. The number and type of potential VOC sources found in basements are significant and problematic, and may warrant advisories regarding the storage and use of potentially strong VOCs sources in basements. PMID:25601281

  10. Predicting residential air exchange rates from questionnaires and meteorology: model evaluation in central North Carolina.

    PubMed

    Breen, Michael S; Breen, Miyuki; Williams, Ronald W; Schultz, Bradley D

    2010-12-15

    A critical aspect of air pollution exposure models is the estimation of the air exchange rate (AER) of individual homes, where people spend most of their time. The AER, which is the airflow into and out of a building, is a primary mechanism for entry of outdoor air pollutants and removal of indoor source emissions. The mechanistic Lawrence Berkeley Laboratory (LBL) AER model was linked to a leakage area model to predict AER from questionnaires and meteorology. The LBL model was also extended to include natural ventilation (LBLX). Using literature-reported parameter values, AER predictions from LBL and LBLX models were compared to data from 642 daily AER measurements across 31 detached homes in central North Carolina, with corresponding questionnaires and meteorological observations. Data was collected on seven consecutive days during each of four consecutive seasons. For the individual model-predicted and measured AER, the median absolute difference was 43% (0.17 h(-1)) and 40% (0.17 h(-1)) for the LBL and LBLX models, respectively. Additionally, a literature-reported empirical scale factor (SF) AER model was evaluated, which showed a median absolute difference of 50% (0.25 h(-1)). The capability of the LBL, LBLX, and SF models could help reduce the AER uncertainty in air pollution exposure models used to develop exposure metrics for health studies.

  11. Latex paint as a delivery vehicle for diethylphthalate and di-n-butylphthalate: predictable boundary layer concentrations and emission rates.

    PubMed

    Schripp, Tobias; Salthammer, Tunga; Fauck, Christian; Bekö, Gabriel; Weschler, Charles J

    2014-10-01

    The description of emission processes of volatile and semi-volatile organic compounds (VOCs and SVOCs) from building products requires a detailed understanding of the material and the air flow conditions at the surface boundary. The mass flux between the surface of the material and air depends on the mass transfer coefficient (hm) through the boundary layer, the gas phase concentration of the target compound immediately adjacent to the material (y0), and the gas-phase concentration in bulk air (y(t)). In the present study emission experiments were performed in two chambers of quite different sizes (0.25 m(3) and 55 m(3)), and, in the larger chamber, at two different temperatures (23°C and 30°C). The emitting material was latex wall paint that had been doped with two plasticizers, diethylphthalate (DEP) and di-n-butylphthalate (DnBP). The phthalate content in the paint was varied in the small chamber experiment to evaluate the impact of the initial concentration in the bulk material (C0) on the emission rate. Boundary layer theory was applied to calculate hm for the specific phthalates from the Sherwood number (Sh) and the diffusion coefficient (Dair). Then y0 was determined based on the bulk gas-phase concentration at steady state (y¯). For both, DEP and DnBP, the y0 obtained was lower than the respective saturation vapor pressure (Ps). Furthermore, for both phthalates in latex paint, the material/air partition coefficient (C0/y0) was close in value to the octanol/air partition coefficient (KOA). This study provides a basis for designing phthalate emitting reference materials that mimic the emission behavior of common building materials.

  12. Photothermal damage is correlated to the delivery rate of time-integrated temperature

    NASA Astrophysics Data System (ADS)

    Denton, Michael L.; Noojin, Gary D.; Gamboa, B. Giovanna; Ahmed, Elharith M.; Rockwell, Benjamin A.

    2016-03-01

    Photothermal damage rate processes in biological tissues are usually characterized by a kinetics approach. This stems from experimental data that show how the transformation of a specified biological property of cells or biomolecule (plating efficiency for viability, change in birefringence, tensile strength, etc.) is dependent upon both time and temperature. However, kinetic methods require determination of kinetic rate constants and knowledge of substrate or product concentrations during the reaction. To better understand photothermal damage processes we have identified temperature histories of cultured retinal cells receiving minimum lethal thermal doses for a variety of laser and culture parameters. These "threshold" temperature histories are of interest because they inherently contain information regarding the fundamental thermal dose requirements for damage in individual cells. We introduce the notion of time-integrated temperature (Tint) as an accumulated thermal dose (ATD) with units of °C s. Damaging photothermal exposure raises the rate of ATD accumulation from that of the ambient (e.g. 37 °C) to one that correlates with cell death (e.g. 52 °C). The degree of rapid increase in ATD (ΔATD) during photothermal exposure depends strongly on the laser exposure duration and the ambient temperature.

  13. Modified perfluorocarbon tracer method for measuring effective multizone air exchange rates.

    PubMed

    Shinohara, Naohide; Kataoka, Toshiyuki; Takamine, Koichi; Butsugan, Michio; Nishijima, Hirokazu; Gamo, Masashi

    2010-09-01

    A modified procedure was developed for the measurement of the effective air exchange rate, which represents the relationship between the pollutants emitted from indoor sources and the residents' level of exposure, by placing the dosers of tracer gas at locations that resemble indoor emission sources. To measure the 24-h-average effective air exchange rates in future surveys based on this procedure, a low-cost, easy-to-use perfluorocarbon tracer (PFT) doser with a stable dosing rate was developed by using double glass vials, a needle, a polyethylene-sintered filter, and a diffusion tube. Carbon molecular sieve cartridges and carbon disulfide (CS₂) were used for passive sampling and extraction of the tracer gas, respectively. Recovery efficiencies, sampling rates, and lower detection limits for 24-h sampling of hexafluorobenzene, octafluorotoluene, and perfluoroallylbenzene were 40% ± 3%, 72% ± 5%, and 84% ± 6%; 10.5 ± 1.1, 14.4 ± 1.4, and 12.2 ± 0.49 mL min⁻¹; and 0.20, 0.17, and 0.26 μg m⁻³, respectively.

  14. Effect of outside air ventilation rate on volatile organic compound concentrations in a call center

    NASA Astrophysics Data System (ADS)

    Hodgson, A. T.; Faulkner, D.; Sullivan, D. P.; DiBartolomeo, D. L.; Russell, M. L.; Fisk, W. J.

    A study of the relationship between outside air ventilation rate and concentrations of volatile organic compounds (VOCs) generated indoors was conducted in a call center office building. The building, with two floors and a total floor area of 4600 m 2, is located in the San Francisco Bay Area, CA. Ventilation rates were manipulated with the building's four air handling units (AHUs). VOC and CO 2 concentrations in the AHU returns were measured on 7 days during a 13-week period. VOC emission factors were determined for individual zones on days when they were operating at near steady-state conditions. The emission factor data were subjected to principal component (PC) analysis to identify groups of co-varying compounds. Potential sources of the PC vectors were ascribed based on information from the literature. The per occupant CO 2 generation rates were 0.0068-0.0092 l s -1. The per occupant isoprene generation rates of 0.2-0.3 mg h -1 were consistent with the value predicted by mass balance from breath concentration and exhalation rate. The relationships between indoor minus outdoor VOC concentrations and ventilation rate were qualitatively examined for eight VOCs. Of these, acetaldehyde and hexanal, which likely were associated with material sources, and decamethylcyclopentasiloxane, associated with personal care products, exhibited general trends of higher concentrations at lower ventilation rates. For other compounds, a clear inverse relationship between VOC concentrations and ventilation was not observed. The net concentration of 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate isomers, examples of low-volatility compounds, changed very little with ventilation likely due to sorption and re-emission effects. These results illustrate that the efficacy of ventilation for controlling VOC concentrations can vary considerably depending upon the operation of the building, the pollutant sources and the physical and chemical processes affecting the pollutants. Thus, source

  15. Heart rate variability biofeedback: Theoretical basis, delivery, and its potential for the treatment of substance use disorders

    PubMed Central

    Eddie, David; Vaschillo, Evgeny; Vaschillo, Bronya; Lehrer, Paul

    2016-01-01

    Heart rate variability biofeedback (HRV BFB) is a biobehavioural clinical intervention that is gaining growing empirical support for the treatment of a number of psychological disorders, several of which are highly comorbid with substance use disorders (SUDs). The present article reviews the autonomic nervous system bases of two key processes implicated in the formation and maintenance of addictive pathology—affect dysregulation and craving—and asks if HRV BFB may be an effective intervention to ameliorate autonomic nervous system dysregulation in these processes, and as such, prove to be an effective intervention for SUDs. A detailed description of HRV BFB and its delivery is provided. Preliminary evidence suggests HRV BFB may be an effective addendum to current first-line SUD treatments, though no firm conclusions can be drawn at this time; more research is needed. PMID:28077937

  16. Relationship of air sampling rates of semipermeable membrane devices with the properties of organochlorine pesticides.

    PubMed

    Zhu, Xiuhua; Ding, Guanghui; Levy, Walkiria; Jakobi, Gert; Schramm, Karl-Werner

    2011-06-01

    The organochlorine pesticides (OCP) in Eastern-Barvaria at Haidel 1160 m a.s.l. were monitored with a low volume active air sampler and semi-permeable membrane devices (SPMD). The air sampling rates (Rair) of SPMD for OCP were calculated. Quantitative structure-property relationship (QSPR) models of Rair of SPMD were developed for OCP with partial least square (PLS) regression. Quantum chemical descriptors computed by semi-empirical PM6 method were used as predictor variables. The cumulative variance of the dependent variable explained by the PLS components and determined by cross-validation (Q(2)cum), for the optimal models, is 0.637, indicating that the model has good predictive ability and robustness, and could be used to estimate Rair values of OCP. The main factors governing Rair of OCP are intermolecular interactions and the energy required for cave-forming in dissolution of OCP into triolein of SPMD.

  17. High-repetition-rate laser ignition of fuel-air mixtures.

    PubMed

    Hsu, Paul S; Roy, Sukesh; Zhang, Zhili; Sawyer, Jordan; Slipchenko, Mikhail N; Mance, Jason G; Gord, James R

    2016-04-01

    A laser-ignition (LI) method is presented that utilizes a high-repetition-rate (HRR) nanosecond laser to reduce minimal ignition energies of individual pulses by ∼10 times while maintaining comparable total energies. The most common LI employs a single nanosecond-laser pulse with energies on the order of tens of millijoules to ignite combustible gaseous mixtures. Because of the requirements of high energy per pulse, fiber coupling of traditional LI systems is difficult to implement in real-world systems with limited optical access. The HRR LI method demonstrated here has an order of magnitude lower per-pulse energy requirement than the traditional single-pulse LI technique, potentially allowing delivery through standard commercial optical fibers. Additionally, the HRR LI approach significantly increases the ignition probability of lean combustible mixtures in high-speed flows while maintaining low individual pulse energies.

  18. Optimal Chest Compression Rate and Compression to Ventilation Ratio in Delivery Room Resuscitation: Evidence from Newborn Piglets and Neonatal Manikins

    PubMed Central

    Solevåg, Anne Lee; Schmölzer, Georg M.

    2017-01-01

    Cardiopulmonary resuscitation (CPR) duration until return of spontaneous circulation (ROSC) influences survival and neurologic outcomes after delivery room (DR) CPR. High quality chest compressions (CC) improve cerebral and myocardial perfusion. Improved myocardial perfusion increases the likelihood of a faster ROSC. Thus, optimizing CC quality may improve outcomes both by preserving cerebral blood flow during CPR and by reducing the recovery time. CC quality is determined by rate, CC to ventilation (C:V) ratio, and applied force, which are influenced by the CC provider. Thus, provider performance should be taken into account. Neonatal resuscitation guidelines recommend a 3:1 C:V ratio. CCs should be delivered at a rate of 90/min synchronized with ventilations at a rate of 30/min to achieve a total of 120 events/min. Despite a lack of scientific evidence supporting this, the investigation of alternative CC interventions in human neonates is ethically challenging. Also, the infrequent occurrence of extensive CPR measures in the DR make randomized controlled trials difficult to perform. Thus, many biomechanical aspects of CC have been investigated in animal and manikin models. Despite mathematical and physiological rationales that higher rates and uninterrupted CC improve CPR hemodynamics, studies indicate that provider fatigue is more pronounced when CC are performed continuously compared to when a pause is inserted after every third CC as currently recommended. A higher rate (e.g., 120/min) is also more fatiguing, which affects CC quality. In post-transitional piglets with asphyxia-induced cardiac arrest, there was no benefit of performing continuous CC at a rate of 90/min. Not only rate but duty cycle, i.e., the duration of CC/total cycle time, is a known determinant of CC effectiveness. However, duty cycle cannot be controlled with manual CC. Mechanical/automated CC in neonatal CPR has not been explored, and feedback systems are under-investigated in this

  19. Measurement of air exchange rates in different indoor environments using continuous CO2 sensors.

    PubMed

    You, Yan; Niu, Can; Zhou, Jian; Liu, Yating; Bai, Zhipeng; Zhang, Jiefeng; He, Fei; Zhang, Nan

    2012-01-01

    A new air exchange rate (AER) monitoring method using continuous CO2 sensors was developed and validated through both laboratory experiments and field studies. Controlled laboratory simulation tests were conducted in a 1-m3 environmental chamber at different AERs (0.1-10.0 hr(-1)). AERs were determined using the decay method based on box model assumptions. Field tests were conducted in classrooms, dormitories, meeting rooms and apartments during 2-5 weekdays using CO2 sensors coupled with data loggers. Indoor temperature, relative humidity (RH), and CO2 concentrations were continuously monitored while outdoor parameters combined with on-site climate conditions were recorded. Statistical results indicated that good laboratory performance was achieved: duplicate precision was within 10%, and the measured AERs were 90%-120% of the real AERs. Average AERs were 1.22, 1.37, 1.10, 1.91 and 0.73 hr(-1) in dormitories, air-conditioned classrooms, classrooms with an air circulation cooling system, reading rooms, and meeting rooms, respectively. In an elderly particulate matter exposure study, all the homes had AER values ranging from 0.29 to 3.46 hr(-1) in fall, and 0.12 to 1.39 hr(-1) in winter with a median AER of 1.15.

  20. Measuring and modeling air exchange rates inside taxi cabs in Los Angeles, California

    NASA Astrophysics Data System (ADS)

    Shu, Shi; Yu, Nu; Wang, Yueyan; Zhu, Yifang

    2015-12-01

    Air exchange rates (AERs) have a direct impact on traffic-related air pollutant (TRAP) levels inside vehicles. Taxi drivers are occupationally exposed to TRAP on a daily basis, yet there is limited measurement of AERs in taxi cabs. To fill this gap, AERs were quantified in 22 representative Los Angeles taxi cabs including 10 Prius, 5 Crown Victoria, 3 Camry, 3 Caravan, and 1 Uplander under realistic driving (RD) conditions. To further study the impacts of window position and ventilation settings on taxi AERs, additional tests were conducted on 14 taxis with windows closed (WC) and on the other 8 taxis with not only windows closed but also medium fan speed (WC-MFS) under outdoor air mode. Under RD conditions, the AERs in all 22 cabs had a mean of 63 h-1 with a median of 38 h-1. Similar AERs were observed under WC condition when compared to those measured under RD condition. Under WC-MFS condition, AERs were significantly increased in all taxi cabs, when compared with those measured under RD condition. A General Estimating Equation (GEE) model was developed and the modeling results showed that vehicle model was a significant factor in determining the AERs in taxi cabs under RD condition. Driving speed and car age were positively associated with AERs but not statistically significant. Overall, AERs measured in taxi cabs were much higher than typical AERs people usually encounter in indoor environments such as homes, offices, and even regular passenger vehicles.

  1. Effects of Temperature, Humidity and Air Flow on Fungal Growth Rate on Loaded Ventilation Filters.

    PubMed

    Tang, W; Kuehn, T H; Simcik, Matt F

    2015-01-01

    This study compares the fungal growth ratio on loaded ventilation filters under various temperature, relative humidity (RH), and air flow conditions in a controlled laboratory setting. A new full-size commercial building ventilation filter was loaded with malt extract nutrients and conidia of Cladosporium sphaerospermum in an ASHRAE Standard 52.2 filter test facility. Small sections cut from this filter were incubated under the following conditions: constant room temperature and a high RH of 97%; sinusoidal temperature (with an amplitude of 10°C, an average of 23°C, and a period of 24 hr) and a mean RH of 97%; room temperature and step changes between 97% and 75% RH, 97% and 43% RH, and 97% and 11% RH every 12 hr. The biomass on the filter sections was measured using both an elution-culture method and by ergosterol assay immediately after loading and every 2 days up to 10 days after loading. Fungal growth was detected earlier using ergosterol content than with the elution-culture method. A student's t-test indicated that Cladosporium sphaerospermum grew better at the constant room temperature condition than at the sinusoidal temperature condition. By part-time exposure to dry environments, the fungal growth was reduced (75% and 43% RH) or even inhibited (11% RH). Additional loaded filters were installed in the wind tunnel at room temperature and an RH greater than 95% under one of two air flow test conditions: continuous air flow or air flow only 9 hr/day with a flow rate of 0.7 m(3)/s (filter media velocity 0.15 m/s). Swab tests and a tease mount method were used to detect fungal growth on the filters at day 0, 5, and 10. Fungal growth was detected for both test conditions, which indicates that when temperature and relative humidity are optimum, controlling the air flow alone cannot prevent fungal growth. In real applications where nutrients are less sufficient than in this laboratory study, fungal growth rate may be reduced under the same operating conditions.

  2. Measurement of Ozone Emission and Particle Removal Rates from Portable Air Purifiers

    ERIC Educational Resources Information Center

    Mang, Stephen A.; Walser, Maggie L.; Nizkorodov, Sergey A.; Laux, John M.

    2009-01-01

    Portable air purifiers are popular consumer items, especially in areas with poor air quality. Unfortunately, most users of these air purifiers have minimal understanding of the factors affecting their efficiency in typical indoor settings. Emission of the air pollutant ozone (O[subscript 3]) by certain air purifiers is of particular concern. In an…

  3. Temperature lapse rates at restricted thermodynamic equilibrium. Part II: Saturated air and further discussions

    NASA Astrophysics Data System (ADS)

    Björnbom, Pehr

    2016-03-01

    In the first part of this work equilibrium temperature profiles in fluid columns with ideal gas or ideal liquid were obtained by numerically minimizing the column energy at constant entropy, equivalent to maximizing column entropy at constant energy. A minimum in internal plus potential energy for an isothermal temperature profile was obtained in line with Gibbs' classical equilibrium criterion. However, a minimum in internal energy alone for adiabatic temperature profiles was also obtained. This led to a hypothesis that the adiabatic lapse rate corresponds to a restricted equilibrium state, a type of state in fact discussed already by Gibbs. In this paper similar numerical results for a fluid column with saturated air suggest that also the saturated adiabatic lapse rate corresponds to a restricted equilibrium state. The proposed hypothesis is further discussed and amended based on the previous and the present numerical results and a theoretical analysis based on Gibbs' equilibrium theory.

  4. Measurement of nonlinear refractive index and ionization rates in air using a wavefront sensor.

    PubMed

    Schwarz, Jens; Rambo, Patrick; Kimmel, Mark; Atherton, Briggs

    2012-04-09

    A wavefront sensor has been used to measure the Kerr nonlinear focal shift of a high intensity ultrashort pulse beam in a focusing beam geometry while accounting for the effects of plasma-defocusing. It is shown that plasma-defocusing plays a major role in the nonlinear focusing dynamics and that measurements of Kerr nonlinearity and ionization are coupled. Furthermore, this coupled effect leads to a novel way that measures the laser ionization rates in air under atmospheric conditions as well as Kerr nonlinearity. The measured nonlinear index n₂ compares well with values found in the literature and the measured ionization rates could be successfully benchmarked to the model developed by Perelomov, Popov, and Terentev (PPT model) [Sov. Phys. JETP 50, 1393 (1966)].

  5. Catchment-scale distribution of radiocesium air dose rate in a mountainous deciduous forest and its relation to topography.

    PubMed

    Atarashi-Andoh, Mariko; Koarashi, Jun; Takeuchi, Erina; Tsuduki, Katsunori; Nishimura, Syusaku; Matsunaga, Takeshi

    2015-09-01

    A large number of air dose rate measurements were collected by walking through a mountainous area with a small gamma-ray survey system, KURAMA-II. The data were used to map the air dose rate of a mountainous deciduous forest that received radiocesium from the Fukushima Dai-ichi Nuclear Power Plant accident. Measurements were conducted in a small stream catchment (0.6 km(2) in area) in August and September 2013, and the relationship between air dose rates and the mountainous topography was examined. Air dose rates increased with elevation, indicating that more radiocesium was deposited on ridges, and suggesting that it had remained there for 2.5 y with no significant downslope migration by soil erosion or water drainage. Orientation in relation to the dominant winds when the radioactive plume flowed to the catchment also strongly affected the air dose rates. Based on our continuous measurements using the KURAMA-II, we describe the variation in air dose rates in a mountainous forest area and suggest that it is important to consider topography when determining sampling points and resolution to assess the spatial variability of dose rates and contaminant deposition.

  6. Effect of air pollutants on the photosynthetic and dark respiration rates of Phaseolus vulgaris

    SciTech Connect

    Borgman, L.M.

    1982-01-01

    The effects of continuous fumigations with pollutant gases on net and gross photosynthesis, dark respiration, respiration/gross photosynthesis ratios, root/shoot ratios, and chloroplast ultrastructure were examined. Plants of Phaseolus vulgaris L. Blue Lakes, were grown in paired plexi-glass chambers. Photosynthetic and respiration rates of 12-19 day-old plants were measured by infrared gas analysis. The plants were dried and root/shoot ratios calculated. A significant increase (28.9%) in gross photosynthesis of plants exposed to 10 ppm. CO was evident compared to the controls. Although net photosynthesis was not significantly affected by 0.035-0.04 ppm NO/sub 2/, gross photosynthesis, dark respiration, and R/G were significantly greater than in controls. Concentrations of 0.04-0.005 SO/sub 2/ resulted in significantly greater respiration and R/G ratios. This procedure resulted in significantly reduced net and gross photosynthetic rates. Ozone exposures of 10-20 ppm for eight hours a day, five days a week, resulted in progressively lower net and gross photosynthetic rates as the week progressed and R/G ratios were significantly higher. Ozone exposures of 6-8 ppm reduced net and gross photosynthetic rates significantly. Average root/shoot ratios of all exposed plants were significantly greater (14.8%) than those grown in pollutant-free air. The concentrations employed were comparable to the federal air pollution standards. It was concluded that these low levels of pollutant gases are capable of altering physiological activities which may result in reduced yield.

  7. Temperature and strain rate effects in high strength high conductivity copper alloys tested in air

    SciTech Connect

    Edwards, D.J.

    1998-03-01

    The tensile properties of the three candidate alloys GlidCop{trademark} Al25, CuCrZr, and CuNiBe are known to be sensitive to the testing conditions such as strain rate and test temperature. This study was conducted on GlidCop Al25 (2 conditions) and Hycon 3HP (3 conditions) to ascertain the effect of test temperature and strain rate when tested in open air. The results show that the yield strength and elongation of the GlidCop Al25 alloys exhibit a strain rate dependence that increases with temperature. Both the GlidCop and the Hycon 3 HP exhibited an increase in strength as the strain rate increased, but the GlidCop alloys proved to be the most strain rate sensitive. The GlidCop failed in a ductile manner irrespective of the test conditions, however, their strength and uniform elongation decreased with increasing test temperature and the uniform elongation also decreased dramatically at the lower strain rates. The Hycon 3 HP alloys proved to be extremely sensitive to test temperature, rapidly losing their strength and ductility when the temperature increased above 250 C. As the test temperature increased and the strain rate decreased the fracture mode shifted from a ductile transgranular failure to a ductile intergranular failure with very localized ductility. This latter observation is based on the presence of dimples on the grain facets, indicating that some ductile deformation occurred near the grain boundaries. The material failed without any reduction in area at 450 C and 3.9 {times} 10{sup {minus}4} s{sup {minus}1}, and in several cases failed prematurely.

  8. Opposed jet diffusion flames of nitrogen-diluted hydrogen vs air - Axial LDA and CARS surveys; fuel/air rates at extinction

    SciTech Connect

    Pellett, G.L.; Northam, G.B.; Wilson, L.G.; Jarrett, O. Jr.; Antcliff, R.R.

    1989-01-01

    An experimental study of H-air counterflow diffusion flames (CFDFs) is reported. Coaxial tubular opposed jet burners were used to form dish-shaped CFDFs centered by opposing laminar jets of H2/N2 and air in an argon bath at 1 atm. Jet velocities for extinction and flame restoration limits are shown versus input H2 concentration. LDA velocity data and CARS temperature and absolute N2, O2 density data give detailed flame structure on the air side of the stagnation point. The results show that air jet velocity is a more fundamental and appropriate measure of H2-air CFDF extinction than input H2 mass flux or fuel jet velocity. It is proposed that the observed constancy of air jet velocity for fuel mixtures containing 80 to 100 percent H2 measure a maximum, kinetically controlled rate at which the CFDF can consume oxygen in air. Fuel velocity mainly measures the input jet momentum required to center an H2/N2 versus air CFDF. 42 refs.

  9. Opposed jet diffusion flames of nitrogen-diluted hydrogen vs air - Axial LDA and CARS surveys; fuel/air rates at extinction

    NASA Technical Reports Server (NTRS)

    Pellett, G. L.; Northam, G. B.; Wilson, L. G.; Jarrett, Olin, Jr.; Antcliff, R. R.

    1989-01-01

    An experimental study of H-air counterflow diffusion flames (CFDFs) is reported. Coaxial tubular opposed jet burners were used to form dish-shaped CFDFs centered by opposing laminar jets of H2/N2 and air in an argon bath at 1 atm. Jet velocities for extinction and flame restoration limits are shown versus input H2 concentration. LDA velocity data and CARS temperature and absolute N2, O2 density data give detailed flame structure on the air side of the stagnation point. The results show that air jet velocity is a more fundamental and appropriate measure of H2-air CFDF extinction than input H2 mass flux or fuel jet velocity. It is proposed that the observed constancy of air jet velocity for fuel mixtures containing 80 to 100 percent H2 measure a maximum, kinetically controlled rate at which the CFDF can consume oxygen in air. Fuel velocity mainly measures the input jet momentum required to center an H2/N2 versus air CFDF.

  10. Development rates of two Xenopsylla flea species in relation to air temperature and humidity.

    PubMed

    Krasnov, B R; Khokhlova, I S; Fielden, L J; Burdelova, N V

    2001-09-01

    The rate of development of immature fleas, Xenopsylla conformis Wagner and Xenopsylla ramesis Rothschild (Siphonaptera: Xenopsyllidae) was studied in the laboratory at 25 degrees C and 28 degrees C with 40, 55, 75 and 92% relative humidity (RH). These fleas are separately associated with the host jird Meriones crassus Sundevall in different microhabitats of the Ramon erosion cirque, Negev Highlands, Israel. This study of basic climatic factors in relation to flea bionomics provides the basis for ecological investigations to interpret reasons for paratopic local distributions of these two species of congeneric fleas on the same host. Both air temperature and RH were positively correlated with duration of egg and larval stages in both species. Change of humidity between egg and larval environments did not affect duration of larval development at any temperature. At each temperature and RH, the eggs and larvae of X. ramesis did not differ between males and females in the duration of their development, whereas female eggs and larvae of X. conformis usually developed significantly faster than those of males. For both species, male pupae developed slower than female pupae at the same air temperature and RH. Air temperature, but not RH, affected the duration of pupal development. At each humidity, duration of the pupal stage was significantly longer at 25 degrees C than at 28 degrees C: 15.3+/-1.7 vs. 11.7+/-1.2 days in X. conformis; 14.1+/-2.0 vs. 11.5+/-1.7 days in X. ramesis, with a significantly shorter pupal period of the latter species at 25 degrees C. These limited interspecific bionomic contrasts in relation to basic climatic factors appear insufficient to explain the differential habitat distributions of X. conformis and X. ramesis.

  11. Air exchange rates and alternative vapor entry pathways to inform vapor intrusion exposure risk assessments.

    PubMed

    Reichman, Rivka; Roghani, Mohammadyousef; Willett, Evan J; Shirazi, Elham; Pennell, Kelly G

    2016-11-12

    Vapor intrusion (VI) is a term used to describe indoor air (IA) contamination that occurs due to the migration of chemical vapors in the soil and groundwater. The overall vapor transport process depends on several factors such as contaminant source characteristics, subsurface conditions, building characteristics, and general site conditions. However, the classic VI conceptual model does not adequately account for the physics of airflow around and inside a building and does not account for chemical emissions from alternative "preferential" pathways (e.g. sewers and other utility connections) into IA spaces. This mini-review provides information about recent research related to building air exchange rates (AERs) and alternative pathways to improve the accuracy of VI exposure risk assessment practices. First, results from a recently published AER study for residential homes across the United States (US) are presented and compared to AERs recommended by the US Environmental Protection Agency (USEPA). The comparison shows considerable differences in AERs when season, location, building age, and other factors are considered. These differences could directly impact VI assessments by influencing IA concentration measurements. Second, a conceptual model for sewer gas entry into buildings is presented and a summary of published field studies is reported. The results of the field studies suggest that alternative pathways for vapors to enter indoor spaces warrant consideration. Ultimately, the information presented in this mini-review can be incorporated into a multiple-lines-of-evidence approach for assessing site-specific VI exposure risks.

  12. Influence of air flow rate and backwashing on the hydraulic behaviour of a submerged filter.

    PubMed

    Cobos-Becerra, Yazmin Lucero; González-Martínez, Simón

    2013-01-01

    The aim of this study was to evaluate backwashing effects on the apparent porosity of the filter media and on the hydraulic behaviour of a pilot scale submerged filter, prior to biofilm colonization, under different hydraulic retention times, and different air flow rates. Tracer curves were analysed with two mathematical models for ideal and non-ideal flow (axial dispersion and Wolf and Resnick models). The filter media was lava stones sieved to 4.5 mm. Backwashing causes attrition of media particles, decreasing the void volume of the filter media and, consequently, the tracer flow is more uniform. The eroded media presented lower dead volumes (79% for the filter with aeration and 8% for the filter without aeration) compared with the new media (83% for the filter with aeration and 22% for the filter without aeration). The flow patterns of eroded and new media were different because the more regular shape of the particles decreases the void volume of the filter media. The dead volume is attributed, in the case of the filter with aeration, to the turbulence caused by the air bubbles that generate preferential channelling of the bulk liquid along the filter media, creating large zones of stagnant liquid and, for the filter without aeration, to the channels formed due to the irregular shaped media.

  13. Analysis of turbulent free jet hydrogen-air diffusion flames with finite chemical reaction rates

    NASA Technical Reports Server (NTRS)

    Sislian, J. P.

    1978-01-01

    The nonequilibrium flow field resulting from the turbulent mixing and combustion of a supersonic axisymmetric hydrogen jet in a supersonic parallel coflowing air stream is analyzed. Effective turbulent transport properties are determined using the (K-epsilon) model. The finite-rate chemistry model considers eight reactions between six chemical species, H, O, H2O, OH, O2, and H2. The governing set of nonlinear partial differential equations is solved by an implicit finite-difference procedure. Radial distributions are obtained at two downstream locations of variables such as turbulent kinetic energy, turbulent dissipation rate, turbulent scale length, and viscosity. The results show that these variables attain peak values at the axis of symmetry. Computed distributions of velocity, temperature, and mass fraction are also given. A direct analytical approach to account for the effect of species concentration fluctuations on the mean production rate of species (the phenomenon of unmixedness) is also presented. However, the use of the method does not seem justified in view of the excessive computer time required to solve the resulting system of equations.

  14. Delivery performance of conventional aircraft by terminal-area, time-based air traffic control: A real-time simulation evaluation

    NASA Technical Reports Server (NTRS)

    Credeur, Leonard; Houck, Jacob A.; Capron, William R.; Lohr, Gary W.

    1990-01-01

    A description and results are presented of a study to measure the performance and reaction of airline flight crews, in a full workload DC-9 cockpit, flying in a real-time simulation of an air traffic control (ATC) concept called Traffic Intelligence for the Management of Efficient Runway-scheduling (TIMER). Experimental objectives were to verify earlier fast-time TIMER time-delivery precision results and obtain data for the validation or refinement of existing computer models of pilot/airborne performance. Experimental data indicated a runway threshold, interarrival-time-error standard deviation in the range of 10.4 to 14.1 seconds. Other real-time system performance parameters measured include approach speeds, response time to controller turn instructions, bank angles employed, and ATC controller message delivery-time errors.

  15. Effect on air quality and flow rate of fresh water production in humidification and dehumidification system

    NASA Astrophysics Data System (ADS)

    Rajasekar, K.; Pugazhenthi, R.; Selvaraju, A.; Manikandan, T.; Saravanan, R.

    2017-03-01

    Water is the vital need of any living organisms of the world when water fails, functions of nature cease the world. The water scarcity is one of the major problems to be faced by the developing world, which indicates a critical need to develop inexpensive small-scale desalination technologies. The cost of the desalination process takes more, so the world expecting the desalination plants with minimum operating cost, so the utilization of renewable energy source is a preferable one. This research article provides a glimpse of an overview of the humidification-dehumidification (HDH) based desalination method which uses the solar energy. The HDH based desalination method monitored and evaluated the performance parameters, i.e. mass flow rates of water and air.

  16. Influence of travel speed on spray deposition uniformity from an air-assisted variable-rate sprayer

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A newly developed LiDAR-guided air-assisted variable-rate sprayer for nursery and orchard applications was tested at various travel speeds to compare its spray deposition and coverage uniformity with constant-rate applications. Spray samplers, including nylon screens and water-sensitive papers (WSP)...

  17. Space Station Freedom seal leakage rate analysis and testing summary: Air leaks in ambient versus vacuum exit conditions

    NASA Technical Reports Server (NTRS)

    Rodriguez, P. I.; Markovitch, R.

    1992-01-01

    This report is intended to reveal the apparent relationship of air seal leakage rates between 2 atmospheres (atm) to 1 atm and 1 atm to vacuum conditions. Gas dynamics analysis is provided as well as data summarizing the MSFC test report, 'Space Station Freedom (S.S. Freedom) Seal Flaw Study With Delta Pressure Leak Rate Comparison Test Report'.

  18. Chemical characterization of indoor air of homes from communes in Xuan Wei, China, with high lung cancer mortality rates

    EPA Science Inventory

    In a rural county, Xuan Wei, China, the lung cancer mortality rate is among China's highest, especially in women. This mortality rate is more associated with indoor air burning of smoky coal, as opposed to smokeless coal or wood, for cooking and heating under unvented conditions....

  19. Effects of metabolic rate on thermal responses at different air velocities in -10 degrees C.

    PubMed

    Mäkinen, T T; Gavhed, D; Holmér, I; Rintamäki, H

    2001-04-01

    The effects of exercise intensity on thermoregulatory responses in cold (-10 degrees C) in a 0.2 (still air, NoWi), 1.0 (Wi1), and 5.0 (Wi5) m x s(-1) wind were studied. Eight young and healthy men, preconditioned in thermoneutral (+20 degrees C) environment for 60 min, walked for 60 min on the treadmill at 2.8 km/h with different combinations of wind and exercise intensity. Exercise level was adjusted by changing the inclination of the treadmill between 0 degrees (lower exercise intensity, metabolic rate 124 W x m(-2), LE) and 6 degrees (higher exercise intensity, metabolic rate 195 W x m(-2), HE). Due to exercise increased heat production and circulatory adjustments, the rectal temperature (T(re)), mean skin temperature (Tsk) and mean body temperature (Tb) were significantly higher at the end of HE in comparison to LE in NoWi and Wi1, and T(re) and Tb also in Wi5. Tsk and Tb were significantly decreased by 5.0 m x s(-1) wind in comparison to NoWi and Wi1. The higher exercise intensity was intense enough to diminish peripheral vasoconstriction and consequently the finger skin temperature was significantly higher at the end of HE in comparison to LE in NoWi and Wi1. Mean heat flux from the skin was unaffected by the exercise intensity. At LE oxygen consumption (VO2) was significantly higher in Wi5 than NoWi and Wi1. Heart rate was unaffected by the wind speed. The results suggest that, with studied exercise intensities, produced without changes in walking speed, the metabolic rate is not so important that it should be taken into consideration in the calculation of wind chill index.

  20. Effectiveness of traffic-related elements in tree bark and pollen abortion rates for assessing air pollution exposure on respiratory mortality rates.

    PubMed

    Carvalho-Oliveira, Regiani; Amato-Lourenço, Luís F; Moreira, Tiana C L; Silva, Douglas R Rocha; Vieira, Bruna D; Mauad, Thais; Saiki, Mitiko; Saldiva, Paulo H Nascimento

    2017-02-01

    The majority of epidemiological studies correlate the cardiorespiratory effects of air pollution exposure by considering the concentrations of pollutants measured from conventional monitoring networks. The conventional air quality monitoring methods are expensive, and their data are insufficient for providing good spatial resolution. We hypothesized that bioassays using plants could effectively determine pollutant gradients, thus helping to assess the risks associated with air pollution exposure. The study regions were determined from different prevalent respiratory death distributions in the Sao Paulo municipality. Samples of tree flower buds were collected from twelve sites in four regional districts. The genotoxic effects caused by air pollution were tested through a pollen abortion bioassay. Elements derived from vehicular traffic that accumulated in tree barks were determined using energy-dispersive X-ray fluorescence spectrometry (EDXRF). Mortality data were collected from the mortality information program of Sao Paulo City. Principal component analysis (PCA) was applied to the concentrations of elements accumulated in tree barks. Pearson correlation and exponential regression were performed considering the elements, pollen abortion rates and mortality data. PCA identified five factors, of which four represented elements related to vehicular traffic. The elements Al, S, Fe, Mn, Cu, and Zn showed a strong correlation with mortality rates (R(2)>0.87) and pollen abortion rates (R(2)>0.82). These results demonstrate that tree barks and pollen abortion rates allow for correlations between vehicular traffic emissions and associated outcomes such as genotoxic effects and mortality data.

  1. Pyrolysis of polymeric materials. I - Effect of chemical structure, temperature, heating rate, and air flow on char yield and toxicity

    NASA Technical Reports Server (NTRS)

    Hilado, C. J.; Casey, C. J.

    1979-01-01

    Various polymeric materials, including synthetic polymers and cellulosic materials, were evaluated at different temperatures, heating rates and air flow rates for thermophysical and toxicological responses. It is shown that char yields appeared to be a function of air access as much as of the chemical structure of the material. It is stated that the sensitivity of the apparent thermal stability of some materials to air access is so marked that thermogravimetric studies in oxygen-free atmospheres may be a consistently misleading approach to comparing synthetic polymers intended to increase fire safety. Toxicity also appeared to be a function of temperature and air access as much as of the chemical structure of the material. Toxicity of the gases evolved seemed to increase with increasing char yield for some polymers.

  2. Analysis of turbulent free-jet hydrogen-air diffusion flames with finite chemical reaction rates

    NASA Technical Reports Server (NTRS)

    Sislian, J. P.; Glass, I. I.; Evans, J. S.

    1979-01-01

    A numerical analysis is presented of the nonequilibrium flow field resulting from the turbulent mixing and combustion of an axisymmetric hydrogen jet in a supersonic parallel ambient air stream. The effective turbulent transport properties are determined by means of a two-equation model of turbulence. The finite-rate chemistry model considers eight elementary reactions among six chemical species: H, O, H2O, OH, O2 and H2. The governing set of nonlinear partial differential equations was solved by using an implicit finite-difference procedure. Radial distributions were obtained at two downstream locations for some important variables affecting the flow development, such as the turbulent kinetic energy and its dissipation rate. The results show that these variables attain their peak values on the axis of symmetry. The computed distribution of velocity, temperature, and mass fractions of the chemical species gives a complete description of the flow field. The numerical predictions were compared with two sets of experimental data. Good qualitative agreement was obtained.

  3. Uneven futures of human lifespans: reckonings from Gompertz mortality rates, climate change, and air pollution.

    PubMed

    Finch, Caleb E; Beltrán-Sánchez, Hiram; Crimmins, Eileen M

    2014-01-01

    The past 200 years have enabled remarkable increases in human lifespans through improvements in the living environment that have nearly eliminated infections as a cause of death through improved hygiene, public health, medicine, and nutrition. We argue that the limit to lifespan may be approaching. Since 1997, no one has exceeded Jeanne Calment's record of 122.5 years, despite an exponential increase of centenarians. Moreover, the background mortality may be approaching a lower limit. We calculate from Gompertz coefficients that further increases in longevity to approach a life expectancy of 100 years in 21st century cohorts would require 50% slower mortality rate accelerations, which would be a fundamental change in the rate of human aging. Looking into the 21st century, we see further challenges to health and longevity from the continued burning of fossil fuels that contribute to air pollution as well as global warming. Besides increased heat waves to which elderly are vulnerable, global warming is anticipated to increase ozone levels and facilitate the spread of pathogens. We anticipate continuing socioeconomic disparities in life expectancy.

  4. Model-based flow rate control for an orfice-type low-volume air sampler

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The standard method of measuring air suspended particulate matter concentration per volume of air consists of continuously drawing a defined volume of air across a filter over an extended period of time, then measuring the mass of the filtered particles and dividing it by the total volume sampled ov...

  5. Relationships between strength and endurance parameters and air depletion rates in professional firefighters.

    PubMed

    Windisch, Stephanie; Seiberl, Wolfgang; Schwirtz, Ansgar; Hahn, Daniel

    2017-03-17

    The aim of this study was to quantify the physical demands of a simulated firefighting circuit and to establish the relationship between job performance and endurance and strength fitness measurements. On four separate days 41 professional firefighters (39 ± 9 yr, 179.6 ± 2.3 cm, 84.4 ± 9.2 kg, BMI 26.1 ± 2.8 kg/m(2)) performed treadmill testing, fitness testing (strength, balance and flexibility) and a simulated firefighting exercise. The firefighting exercise included ladder climbing (20 m), treadmill walking (200 m), pulling a wire rope hoist (15 times) and crawling an orientation section (50 m). Firefighting performance during the simulated exercise was evaluated by a simple time-strain-air depletion model (TSA) taking the sum of z-transformed parameters of time to finish the exercise, strain in terms of mean heart rate, and air depletion from the breathing apparatus. Multiple regression analysis based on the TSA-model served for the identification of the physiological determinants most relevant for professional firefighting. Three main factors with great influence on firefighting performance were identified (70.1% of total explained variance): VO2peak, the time firefighter exercised below their individual ventilatory threshold and mean breathing frequency. Based on the identified main factors influencing firefighting performance we recommend a periodic preventive health screening for incumbents to monitor peak VO2 and individual ventilatory threshold.

  6. Relationships between strength and endurance parameters and air depletion rates in professional firefighters

    PubMed Central

    Windisch, Stephanie; Seiberl, Wolfgang; Schwirtz, Ansgar; Hahn, Daniel

    2017-01-01

    The aim of this study was to quantify the physical demands of a simulated firefighting circuit and to establish the relationship between job performance and endurance and strength fitness measurements. On four separate days 41 professional firefighters (39 ± 9 yr, 179.6 ± 2.3 cm, 84.4 ± 9.2 kg, BMI 26.1 ± 2.8 kg/m2) performed treadmill testing, fitness testing (strength, balance and flexibility) and a simulated firefighting exercise. The firefighting exercise included ladder climbing (20 m), treadmill walking (200 m), pulling a wire rope hoist (15 times) and crawling an orientation section (50 m). Firefighting performance during the simulated exercise was evaluated by a simple time-strain-air depletion model (TSA) taking the sum of z-transformed parameters of time to finish the exercise, strain in terms of mean heart rate, and air depletion from the breathing apparatus. Multiple regression analysis based on the TSA-model served for the identification of the physiological determinants most relevant for professional firefighting. Three main factors with great influence on firefighting performance were identified (70.1% of total explained variance): VO2peak, the time firefighter exercised below their individual ventilatory threshold and mean breathing frequency. Based on the identified main factors influencing firefighting performance we recommend a periodic preventive health screening for incumbents to monitor peak VO2 and individual ventilatory threshold. PMID:28303944

  7. Measurement of air exchange rate of stationary vehicles and estimation of in-vehicle exposure.

    PubMed

    Park, J H; Spengler, J D; Yoon, D W; Dumyahn, T; Lee, K; Ozkaynak, H

    1998-01-01

    The air exchange rates or air changes per hour (ACH) were measured under 4 conditions in 3 stationary automobiles. The ACH ranged between 1.0 and 3.0 h-1 with windows closed and no mechanical ventilation, between 1.8 and 3.7 h-1 for windows closed with fan set on recirculation, between 13.3 and 26.1 h-1 for window open with no mechanical ventilation, and between 36.2 and 47.5 h-1 for window closed with the fan set on fresh air. ACHs for windows closed with no ventilation were higher for the older automobile than for the newer automobiles. With the windows closed and fan turned off, ACH was not influenced by wind speed (p > 0.05). When the window was open, ACH appeared to be greatly affected by wind speed (R2 = 0.86). These measurements are relevant to understanding exposures inside automobiles to sources such as dry-cleaned clothes, cigarettes and airbags. Therefore, to understand the in-vehicle exposure to these internal sources, perchloroethylene (PCE) emitted from dry-cleaned clothes and environmental tobacco smoke (ETS) inside a vehicle were modeled for simulated driving cycles. Airbag deployment was also modeled for estimating exposure level to alkaline particulate and carbon monoxide (CO). Average exposure to PCE inside a vehicle for 30 minutes period was high (approximately 780 micrograms/m3); however, this is only 6% of the two-week exposure that is influenced by the storage of dry cleaned clothing at home. On the other hand, the exposure levels of respirable suspended particulate (RSP) and formaldehyde due to ETS could reach 2.1 mg/m3 and 0.11 ppm, respectively, when a person smokes inside a driving car even with the window open. In modeling the in-vehicle concentrations following airbag deployment, the average CO level over 20 minutes would not appear to present problem (less than 28 ppm). The peak concentration of respirable particulate would have exceeded 140 mg/m3. Since most of the particle mass is composed of alkaline material, these high levels

  8. Comparison BIPM.RI(I)-K8 of high dose rate 192Ir brachytherapy standards for reference air kerma rate of the NPL and the BIPM

    NASA Astrophysics Data System (ADS)

    Alvarez, J. T.; Sander, T.; de Pooter, J. A.; Allisy-Roberts, P. J.; Kessler, C.

    2014-01-01

    An indirect comparison of the standards for reference air kerma rate for 192Ir high dose rate brachytherapy sources of the National Physical Laboratory (NPL), United Kingdom, and of the Bureau International des Poids et Mesures (BIPM) was carried out at the NPL in June 2010. The comparison result, based on the calibration coefficients for a transfer standard and expressed as a ratio of the NPL and the BIPM standards for reference air kerma rate, is 0.9989 with a combined standard uncertainty of 0.0057. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  9. Modelling evolution of air dose rates in river basins in Fukushima Prefecture affected by sediment-sorbed radiocesium redistribution

    NASA Astrophysics Data System (ADS)

    Malins, A.; Sakuma, K.; Nakanishi, T.; Kurikami, H.; Machida, M.; Kitamura, A.; Yamada, S.

    2015-12-01

    The radioactive 134Cs and 137Cs isotopes deposited over Fukushima Prefecture by the Fukushima Daiichi nuclear disaster are the predominant radiological concern for the years following the accident. This is because the energetic gamma radiation they emit on decay constitutes the majority of the elevated air dose rates that now afflict the region. Therefore, we developed a tool for calculating air dose rates from arbitrary radiocesium spatial distributions across the land surface and depth profiles within the ground. As cesium is strongly absorbed by clay soils, its primary redistribution mechanism within Fukushima Prefecture is by soil erosion and water-borne sediment transport. Each year between 0.1~1% of the total radiocesium inventory in the river basins neighboring Fukushima Daiichi is eroded from the land surface and enters into water courses, predominantly during typhoon storms. Although this is a small amount in relative terms, in absolute terms it corresponds to terabecquerels of 134Cs and 137Cs redistribution each year and this can affect the air dose rate at locations of high erosion and sediment deposition. This study inputs the results of sediment redistribution simulations into the dose rate evaluation tool to calculate the locations and magnitude of air dose rate changes due to radiocesium redistribution. The dose rate calculations are supported by handheld survey instrument results taken within the Prefecture.

  10. Feasibility Study: Ductless Hydronic Distribution Systems with Fan Coil Delivery

    SciTech Connect

    Springer, D.; Dakin, B.; Backman, C.

    2012-07-01

    The primary objectives of this study are to estimate potential energy savings relative to conventional ducted air distribution, and to identify equipment requirements, costs, and barriers with a focus on ductless hydronic delivery systems that utilize water-to-air terminal units in each zone. Results indicate that annual heating and cooling energy use can be reduced by up to 27% assuming replacement of the conventional 13 SEER heat pump and coil with a similarly rated air-to-water heat pump.

  11. MO-D-213-07: RadShield: Semi- Automated Calculation of Air Kerma Rate and Barrier Thickness

    SciTech Connect

    DeLorenzo, M; Wu, D; Rutel, I; Yang, K

    2015-06-15

    Purpose: To develop the first Java-based semi-automated calculation program intended to aid professional radiation shielding design. Air-kerma rate and barrier thickness calculations are performed by implementing NCRP Report 147 formalism into a Graphical User Interface (GUI). The ultimate aim of this newly created software package is to reduce errors and improve radiographic and fluoroscopic room designs over manual approaches. Methods: Floor plans are first imported as images into the RadShield software program. These plans serve as templates for drawing barriers, occupied regions and x-ray tube locations. We have implemented sub-GUIs that allow the specification in regions and equipment for occupancy factors, design goals, number of patients, primary beam directions, source-to-patient distances and workload distributions. Once the user enters the above parameters, the program automatically calculates air-kerma rate at sampled points beyond all barriers. For each sample point, a corresponding minimum barrier thickness is calculated to meet the design goal. RadShield allows control over preshielding, sample point location and material types. Results: A functional GUI package was developed and tested. Examination of sample walls and source distributions yields a maximum percent difference of less than 0.1% between hand-calculated air-kerma rates and RadShield. Conclusion: The initial results demonstrated that RadShield calculates air-kerma rates and required barrier thicknesses with reliable accuracy and can be used to make radiation shielding design more efficient and accurate. This newly developed approach differs from conventional calculation methods in that it finds air-kerma rates and thickness requirements for many points outside the barriers, stores the information and selects the largest value needed to comply with NCRP Report 147 design goals. Floor plans, parameters, designs and reports can be saved and accessed later for modification and recalculation

  12. Dynamic evaluation of airflow rates for a variable air volume system serving an open-plan office.

    PubMed

    Mai, Horace K W; Chan, Daniel W T; Burnett, John

    2003-09-01

    In a typical air-conditioned office, the thermal comfort and indoor air quality are sustained by delivering the amount of supply air with the correct proportion of outdoor air to the breathing zone. However, in a real office, it is not easy to measure these airflow rates supplied to space, especially when the space is served by a variable air volume (VAV) system. The most accurate method depends on what is being measured, the details of the building and types of ventilation system. The constant concentration tracer gas method as a means to determine ventilation system performance, however, this method becomes more complicated when the air, including the tracer gas is allowed to recirculate. An accurate measurement requires significant resource support in terms of instrumentation set up and also professional interpretation. This method deters regular monitoring of the performance of an airside systems by building managers, and hence the indoor environmental quality, in terms of thermal comfort and indoor air quality, may never be satisfactory. This paper proposes a space zone model for the calculation of all the airflow parameters based on tracer gas measurements, including flow rates of outdoor air, VAV supply, return space, return and exfiltration. Sulphur hexafluoride (SF6) and carbon dioxide (CO2) are used as tracer gases. After using both SF6 and CO2, the corresponding results provide a reference to justify the acceptability of using CO2 as the tracer gas. The validity of using CO2 has the significance that metabolic carbon dioxide can be used as a means to evaluate real time airflow rates. This approach provides a practical protocol for building managers to evaluate the performance of airside systems.

  13. Stretch-Induced Drug Delivery from Superhydrophobic Polymer Composites: Use of Crack Propagation Failure Modes for Controlling Release Rates.

    PubMed

    Wang, Julia; Kaplan, Jonah A; Colson, Yolonda L; Grinstaff, Mark W

    2016-02-18

    The concept of using crack propagation in polymeric materials to control drug release and its first demonstration are reported. The composite drug delivery system consists of highly-textured superhydrophobic electrosprayed microparticle coatings, composed of biodegradable and biocompatible polymers poly(caprolactone) and poly(glycerol monostearate carbonate-co-caprolactone), and a cellulose/polyester core. The release of entrapped agents is controlled by the magnitude of applied strain, resulting in a graded response from water infiltration through the propagating patterned cracks in the coating. Strain-dependent delivery of the anticancer agents cisplatin and 7-ethyl-10-hydroxycamptothecin to esophageal cancer cells (OE33) in vitro is observed. Finally the device is integrated with an esophageal stent to demonstrate delivery of fluorescein diacetate, using applied tension, to an ex vivo esophagus.

  14. E-beam treatment of trichloroethylene-air mixtures: Products and rates

    NASA Astrophysics Data System (ADS)

    Mill, Theodore; Su, Minggong; David Yao, C. C.; Matthews, Stephen M.; Wang, Francis T. S.

    1997-09-01

    Electron beam (E-beam) treatment of 3000 ppmv trichloroethylene (TCE) vapor in dry and wet air led to rapid, nearly quantitative, conversion of TCE to dichloroacetyl chloride, plus small amounts of phosgene. Higher E-beam doses, up to 110 kGy, led to oxidation of the initial products to CO, CO 2, HCl and Cl 2. The results parallel results found for photo- and Cl-atom initiated oxidation of TCE vapor, and are accounted for by an efficient Cl-atom chain oxidation. Lack of effect of 28,000 ppmv water vapor (90% RH) on rates or products reflects a very high efficiency for the Cl-atom chain oxidation and the very slow reaction of vapor phase water with acyl halides. Irradiation experiments conducted with TCE dissolved in aerated and deaerated water at 10 and 300 ppm showed marked differences in radiolytic products from those found in the vapor phase. A preliminary cost estimate indicates that E-beam treatment of TCE vapor is very competitive with conventional activated carbon treatment and catalytic oxidation.

  15. Measuring OutdoorAir Intake Rates Using Electronic Velocity Sensors at Louvers and Downstream of Airflow Straighteners

    SciTech Connect

    Fisk, William; Sullivan, Douglas; Cohen, Sebastian; Han, Hwataik

    2008-10-01

    Practical and accurate technologies are needed for continuously measuring and controlling outdoor air (OA) intake rates in commercial building heating, ventilating, and air conditioning (HVAC) systems. This project evaluated two new measurement approaches. Laboratory experiments determined that OA flow rates were measurable with errors generally less than 10percent using electronic air velocity probes installed between OA intake louver blades or at the outlet face of louvers. High accuracy was maintained with OA flow rates as low as 15percent of the maximum for the louvers. Thus, with this measurement approach HVAC systems do not need separate OA intakes for minimum OA supply. System calibration parameters are required for each unique combination of louver type and velocity sensor location but calibrations are not necessary for each system installation. The research also determined that the accuracy of measuring OA flow rates with velocity probes located in the duct downstream of the intake louver was not improved by installing honeycomb airflow straighteners upstream of the probes. Errors varied with type of upstream louver, were as high as 100percent, and were often greater than 25percent. In conclusion, use of electronic air velocity probes between the blades of OA intake louvers or at the outlet face of louvers is a highly promising means of accurately measuring rates of OA flow into HVAC systems. The use of electronic velocity probes downstream of airflow straighteners is less promising, at least with the relatively small OA HVAC inlet systems employed in this research.

  16. 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.

  17. Ablation rate, caries removal, and restoration using Nd:YAG and Er:YAG lasers and air abrasion

    NASA Astrophysics Data System (ADS)

    White, Joel M.

    1998-04-01

    This study evaluated the ablation rate in dentin and enamel of the Nd:YAG laser (1 - 2W, 10Hz) and the Er:YAG laser (1 - 2.5W, 10Hz), compared to the high-speed drill, low-speed drill and air abrasion (fine and extra-fine particle size). Subsequently, the effectiveness of caries removal and restoration in enamel of the Nd:YAG laser at the same powers and pulse repetition rate was compared to the high-speed drill, low-speed drill, and air abrasion. Enamel and dentin of 1mm thick mid-coronal sections from extracted third molars were ablated by Er:YAG laser ((lambda) equals 2.94 micrometer), Nd:YAG laser ((lambda) equals 1.06 micrometer) both with air/water spray, high-speed drill with 300 carbide bur, and low-speed drill with $1/4 round bur and air abrasions at 160 psi, with fine air abrasion at 50 micrometer and extra fine at 27 micrometer particle size. Removal (ablation) rate defined as dentin or enamel thickness divided by time required for perforation of the samples was determined for lasers, drills and air abrasion. Multifactor randomized ANOVA (p less than 0.05) considered removal rate as a function of treatment conditions. Removal Rate (micrometers per second) Enamel Dentin High-speed drill 273 +/- 47.34 493 +/- 1.73 Low-speed drill 0 42 +/- 14.25 Nd:YAG 2W 0 103 +/- 37 Er:YAG 2W 35 +/- 10 348 +/- 101 Air abrasion/fine 220 +/- 27 433 +/- 99 Air abrasion/extra fine 151 +/- 13 203 +/- 30 Er:YAG laser at 2W 10Hz ablated both enamel and dentin faster than the low-speed drill but slower than the high-speed drill, while the Nd:YAG laser at identical power and pulse rate did not ablate healthy enamel but was capable of removing dentin. To determine caries removal rate in enamel, extracted superficial carious molars (n equals 35) that included minimal explorer penetration and radiographic confirmation of caries extent were selected. Samples were randomly distributed into treatment groups: high-speed drill (HS), low-speed drill (LS), Nd:YAG laser (L), Nd:YAG with air

  18. Air Vehicle Technology Integration Program (AVTIP). Delivery Order 0033: Advanced Sol-Gel Adhesion Processes - Transition Support

    DTIC Science & Technology

    2005-07-01

    or without an additional acid desmut. The use of an open air plasma process may improve the surface cleanliness, but the results were not conclusive...from PlasmaTreat -North America was used to clean and activate the surface of the aluminum alloy. This process blasts the surface of an object on the...conditioner with or without an additional acid desmut. The use of an open air plasma process may improve the surface cleanliness, but the results

  19. Modeling Spatial and Temporal Variability of Residential Air Exchange Rates for the Near-Road Exposures and Effects of Urban Air Pollutants Study (NEXUS)

    PubMed Central

    Breen, Michael S.; Burke, Janet M.; Batterman, Stuart A.; Vette, Alan F.; Godwin, Christopher; Croghan, Carry W.; Schultz, Bradley D.; Long, Thomas C.

    2014-01-01

    Air pollution health studies often use outdoor concentrations as exposure surrogates. Failure to account for variability of residential infiltration of outdoor pollutants can induce exposure errors and lead to bias and incorrect confidence intervals in health effect estimates. The residential air exchange rate (AER), which is the rate of exchange of indoor air with outdoor air, is an important determinant for house-to-house (spatial) and temporal variations of air pollution infiltration. Our goal was to evaluate and apply mechanistic models to predict AERs for 213 homes in the Near-Road Exposures and Effects of Urban Air Pollutants Study (NEXUS), a cohort study of traffic-related air pollution exposures and respiratory effects in asthmatic children living near major roads in Detroit, Michigan. We used a previously developed model (LBL), which predicts AER from meteorology and questionnaire data on building characteristics related to air leakage, and an extended version of this model (LBLX) that includes natural ventilation from open windows. As a critical and novel aspect of our AER modeling approach, we performed a cross validation, which included both parameter estimation (i.e., model calibration) and model evaluation, based on daily AER measurements from a subset of 24 study homes on five consecutive days during two seasons. The measured AER varied between 0.09 and 3.48 h−1 with a median of 0.64 h−1. For the individual model-predicted and measured AER, the median absolute difference was 29% (0.19 h‑1) for both the LBL and LBLX models. The LBL and LBLX models predicted 59% and 61% of the variance in the AER, respectively. Daily AER predictions for all 213 homes during the three year study (2010–2012) showed considerable house-to-house variations from building leakage differences, and temporal variations from outdoor temperature and wind speed fluctuations. Using this novel approach, NEXUS will be one of the first epidemiology studies to apply calibrated

  20. Modeling spatial and temporal variability of residential air exchange rates for the Near-Road Exposures and Effects of Urban Air Pollutants Study (NEXUS).

    PubMed

    Breen, Michael S; Burke, Janet M; Batterman, Stuart A; Vette, Alan F; Godwin, Christopher; Croghan, Carry W; Schultz, Bradley D; Long, Thomas C

    2014-11-07

    Air pollution health studies often use outdoor concentrations as exposure surrogates. Failure to account for variability of residential infiltration of outdoor pollutants can induce exposure errors and lead to bias and incorrect confidence intervals in health effect estimates. The residential air exchange rate (AER), which is the rate of exchange of indoor air with outdoor air, is an important determinant for house-to-house (spatial) and temporal variations of air pollution infiltration. Our goal was to evaluate and apply mechanistic models to predict AERs for 213 homes in the Near-Road Exposures and Effects of Urban Air Pollutants Study (NEXUS), a cohort study of traffic-related air pollution exposures and respiratory effects in asthmatic children living near major roads in Detroit, Michigan. We used a previously developed model (LBL), which predicts AER from meteorology and questionnaire data on building characteristics related to air leakage, and an extended version of this model (LBLX) that includes natural ventilation from open windows. As a critical and novel aspect of our AER modeling approach, we performed a cross validation, which included both parameter estimation (i.e., model calibration) and model evaluation, based on daily AER measurements from a subset of 24 study homes on five consecutive days during two seasons. The measured AER varied between 0.09 and 3.48 h(-1) with a median of 0.64 h(-1). For the individual model-predicted and measured AER, the median absolute difference was 29% (0.19 h‑1) for both the LBL and LBLX models. The LBL and LBLX models predicted 59% and 61% of the variance in the AER, respectively. Daily AER predictions for all 213 homes during the three year study (2010-2012) showed considerable house-to-house variations from building leakage differences, and temporal variations from outdoor temperature and wind speed fluctuations. Using this novel approach, NEXUS will be one of the first epidemiology studies to apply calibrated and

  1. Intensity-modulated radiation therapy for pancreatic and prostate cancer using pulsed low–dose rate delivery techniques

    SciTech Connect

    Li, Jie; Lang, Jinyi; Wang, Pei; Kang, Shengwei; Lin, Mu-han; Chen, Xiaoming; Chen, Fu; Guo, Ming; Chen, Lili; Ma, Chang-Ming Charlie

    2014-01-01

    Reirradiation of patients who were previously treated with radiotherapy is vastly challenging. Pulsed low–dose rate (PLDR) external beam radiotherapy has the potential to reduce normal tissue toxicities while providing significant tumor control for recurrent cancers. This work investigates treatment planning techniques for intensity-modulated radiation therapy (IMRT)-based PLDR treatment of various sites, including cases with pancreatic and prostate cancer. A total of 20 patients with clinical recurrence were selected for this study, including 10 cases with pancreatic cancer and 10 with prostate cancer. Large variations in the target volume were included to test the ability of IMRT using the existing treatment planning system and optimization algorithm to deliver uniform doses in individual gantry angles/fields for PLDR treatments. Treatment plans were generated with 10 gantry angles using the step-and-shoot IMRT delivery technique, which can be delivered in 3-minute intervals to achieve an effective low dose rate of 6.7 cGy/min. Instead of dose constraints on critical structures, ring structures were mainly used in PLDR-IMRT optimization. In this study, the PLDR-IMRT plans were compared with the PLDR-3-dimensional conformal radiation therapy (3DCRT) plans and the PLDR-RapidArc plans. For the 10 cases with pancreatic cancer that were investigated, the mean planning target volume (PTV) dose for each gantry angle in the PLDR-IMRT plans ranged from 17.6 to 22.4 cGy. The maximum doses ranged between 22.9 and 34.8 cGy. The minimum doses ranged from 8.2 to 17.5 cGy. For the 10 cases with prostate cancer that were investigated, the mean PTV doses for individual gantry angles ranged from 18.8 to 22.6 cGy. The maximum doses per gantry angle were between 24.0 and 34.7 cGy. The minimum doses per gantry angle ranged from 4.4 to 17.4 cGy. A significant reduction in the organ at risk (OAR) dose was observed with the PLDR-IMRT plan when compared with that using the PLDR-3DCRT

  2. EFFECT OF VENTILATION SYSTEMS AND AIR FILTERS ON DECAY RATES OF PARTICLES PRODUCED BY INDOOR SOURCES IN AN OCCUPIED TOWNHOUSE

    EPA Science Inventory

    Several studies have shown the importance of particle losses in real homes due to deposition and filtration; however, none have quantitatively shown the impact of using a central forced air fan and in-duct filter on particle loss rates. In an attempt to provide such data, we me...

  3. Development and Evaluation of a New Air Exchange Rate Algorithm for the Stochastic Human Exposure and Dose Simulation Model

    EPA Science Inventory

    between-home and between-city variability in residential pollutant infiltration. This is likely a result of differences in home ventilation, or air exchange rates (AER). The Stochastic Human Exposure and Dose Simulation (SHEDS) model is a population exposure model that uses a pro...

  4. CHANGES IN HEART RATE VARIABILITY AND LUNG FUNCTION OBSERVED IN NC PATROL TROOPERS EXPOSED TO PM AND AIR TOXICS

    EPA Science Inventory

    Changes in Heart Rate Variability and Lung Function in NC Patrol Troopers exposed to PM and Air Toxics

    Michael Riediker1, Wayne E Cascio1, Robert B Devlin2, Thomas Griggs1&4, Margaret Herbst1, Ronald W Williams3, Steve P McCorquodale4, Philip A Bromberg1
    1) University o...

  5. INVESTIGATING THE INFLUENCE OF RELATIVE HUMIDITY, AIR VELOCITY, AND AMPLIFICATION ON THE EMISSION RATES OF FUNGAL SPORES

    EPA Science Inventory

    The paper discusses the impact of relative humidity (RH), air velocity, and surface growth on the emission rates of fungal spores from the surface of contaminated material. Although the results show a complex interaction of factors, we have determined, for this limited data set,...

  6. The IPEM code of practice for determination of the reference air kerma rate for HDR (192)Ir brachytherapy sources based on the NPL air kerma standard.

    PubMed

    Bidmead, A M; Sander, T; Locks, S M; Lee, C D; Aird, E G A; Nutbrown, R F; Flynn, A

    2010-06-07

    This paper contains the recommendations of the high dose rate (HDR) brachytherapy working party of the UK Institute of Physics and Engineering in Medicine (IPEM). The recommendations consist of a Code of Practice (COP) for the UK for measuring the reference air kerma rate (RAKR) of HDR (192)Ir brachytherapy sources. In 2004, the National Physical Laboratory (NPL) commissioned a primary standard for the realization of RAKR of HDR (192)Ir brachytherapy sources. This has meant that it is now possible to calibrate ionization chambers directly traceable to an air kerma standard using an (192)Ir source (Sander and Nutbrown 2006 NPL Report DQL-RD 004 (Teddington: NPL) http://publications.npl.co.uk). In order to use the source specification in terms of either RAKR, Κ(R) (ICRU 1985 ICRU Report No 38 (Washington, DC: ICRU); ICRU 1997 ICRU Report No 58 (Bethesda, MD: ICRU)), or air kerma strength, S(K) (Nath et al 1995 Med. Phys. 22 209-34), it has been necessary to develop algorithms that can calculate the dose at any point around brachytherapy sources within the patient tissues. The AAPM TG-43 protocol (Nath et al 1995 Med. Phys. 22 209-34) and the 2004 update TG-43U1 (Rivard et al 2004 Med. Phys. 31 633-74) have been developed more fully than any other protocol and are widely used in commercial treatment planning systems. Since the TG-43 formalism uses the quantity air kerma strength, whereas this COP uses RAKR, a unit conversion from RAKR to air kerma strength was included in the appendix to this COP. It is recommended that the measured RAKR determined with a calibrated well chamber traceable to the NPL (192)Ir primary standard is used in the treatment planning system. The measurement uncertainty in the source calibration based on the system described in this COP has been reduced considerably compared to other methods based on interpolation techniques.

  7. Is volcanic air pollution associated with decreased heart-rate variability?

    PubMed Central

    Chow, Dominic C; Grandinetti, Andrew; Fernandez, Ed; Sutton, A J; Elias, Tamar; Brooks, Barbara; Tam, Elizabeth K

    2010-01-01

    Objectives To determine the autonomic cardiovascular control among residents of Hawaii who are exposed to varying levels of volcanic air pollution (vog), which consists largely of sulfur dioxide (SO2) and acid aerosols. Methods In a cross-sectional study between April 2006 and June 2008, the authors measured cardiovagal autonomic function by heart-rate variability (HRV) in 72 healthy individuals who lived in four exposure zones on Hawaii Island: vog-free (n=18); episodic exposure to SO2 >200 ppb and acid aerosol (n=19); chronic exposure to SO2 ≥30 ppb and acid aerosol (n=15); and chronic exposure to acid aerosols (n=20). Individuals with diabetes or heart disease, or who had smoked in the preceding month were excluded. HRV was measured in all subjects during rest, paced breathing and active standing (Ewing manoeuvre). HRV was analysed in time and frequency domains and compared between the four exposure zones. Results There were no significant differences between exposure zones in HRV, in either time or frequency domains, even after adjustment for age, gender, ethnicity and body mass index. There was no significant HRV change in three individuals in whom HRV was measured before and during an exposure to combined SO2 100–250 ppb and concentration of respirable particles of diameter ≤2.5 μ (PM2.5) >500 μg/m3. Age was significantly correlated with time-domain parameters during paced breathing and the Ewing manoeuvre. Conclusions This study of healthy individuals found no appreciable effects of vog on the autonomic nervous system. PMID:21546995

  8. The air dose rate around the Fukushima Dai-ichi Nuclear Power Plant: its spatial characteristics and temporal changes until December 2012.

    PubMed

    Mikami, Satoshi; Maeyama, Takeshi; Hoshide, Yoshifumi; Sakamoto, Ryuichi; Sato, Shoji; Okuda, Naotoshi; Sato, Tetsuro; Takemiya, Hiroshi; Saito, Kimiaki

    2015-01-01

    Distribution maps of air dose rates around the Fukushima Dai-ichi Nuclear Power Plant were constructed using the results of measurement obtained from approximately 6500 locations (at most) per measurement period. The measurements were conducted 1 m above the ground using survey meters in flat and spatially open locations. Spatial distribution and temporal change of the air dose rate in the area were revealed by examining the resultant distribution maps. The observed reduction rate of the air dose rate over the 18 months between June 2011 and December 2012 was greater than that calculated from radioactive decay of radiocesium by 10% in relative percentage except decontaminated sites. This 10% difference in the reduction of the air dose rate can be explained by the mobility of radiocesium in the depth direction. In the region where the air dose rate was lower than 0.25 μSv h(-1) on June 2011, the reduction of the air dose rate was observed to be smaller than that of the other dose rate regions, and it was in fact smaller than the reduction rate caused by radioactive decay alone. In contrast, the reduction rate was larger in regions with higher air dose rates. In flat and spatially open locations, no significant difference in the reduction tendency of air dose rates was observed among different land use classifications (rice fields, farmland, forests, and building sites).

  9. Seasonal Variations of Indoor Microbial Exposures and Their Relation to Temperature, Relative Humidity, and Air Exchange Rate

    PubMed Central

    Bekö, Gabriel; Timm, Michael; Gustavsen, Sine; Hansen, Erik Wind

    2012-01-01

    Indoor microbial exposure has been related to adverse pulmonary health effects. Exposure assessment is not standardized, and various factors may affect the measured exposure. The aim of this study was to investigate the seasonal variation of selected microbial exposures and their associations with temperature, relative humidity, and air exchange rates in Danish homes. Airborne inhalable dust was sampled in five Danish homes throughout the four seasons of 1 year (indoors, n = 127; outdoors, n = 37). Measurements included culturable fungi and bacteria, endotoxin, N-acetyl-beta-d-glucosaminidase, total inflammatory potential, particles (0.75 to 15 μm), temperature, relative humidity, and air exchange rates. Significant seasonal variation was found for all indoor microbial exposures, excluding endotoxin. Indoor fungi peaked in summer (median, 235 CFU/m3) and were lowest in winter (median, 26 CFU/m3). Indoor bacteria peaked in spring (median, 2,165 CFU/m3) and were lowest in summer (median, 240 CFU/m3). Concentrations of fungi were predominately higher outdoors than indoors, whereas bacteria, endotoxin, and inhalable dust concentrations were highest indoors. Bacteria and endotoxin correlated with the mass of inhalable dust and number of particles. Temperature and air exchange rates were positively associated with fungi and N-acetyl-beta-d-glucosaminidase and negatively with bacteria and the total inflammatory potential. Although temperature, relative humidity, and air exchange rates were significantly associated with several indoor microbial exposures, they could not fully explain the observed seasonal variations when tested in a mixed statistical model. In conclusion, the season significantly affects indoor microbial exposures, which are influenced by temperature, relative humidity, and air exchange rates. PMID:23001651

  10. Seasonal variations of indoor microbial exposures and their relation to temperature, relative humidity, and air exchange rate.

    PubMed

    Frankel, Mika; Bekö, Gabriel; Timm, Michael; Gustavsen, Sine; Hansen, Erik Wind; Madsen, Anne Mette

    2012-12-01

    Indoor microbial exposure has been related to adverse pulmonary health effects. Exposure assessment is not standardized, and various factors may affect the measured exposure. The aim of this study was to investigate the seasonal variation of selected microbial exposures and their associations with temperature, relative humidity, and air exchange rates in Danish homes. Airborne inhalable dust was sampled in five Danish homes throughout the four seasons of 1 year (indoors, n = 127; outdoors, n = 37). Measurements included culturable fungi and bacteria, endotoxin, N-acetyl-beta-d-glucosaminidase, total inflammatory potential, particles (0.75 to 15 μm), temperature, relative humidity, and air exchange rates. Significant seasonal variation was found for all indoor microbial exposures, excluding endotoxin. Indoor fungi peaked in summer (median, 235 CFU/m(3)) and were lowest in winter (median, 26 CFU/m(3)). Indoor bacteria peaked in spring (median, 2,165 CFU/m(3)) and were lowest in summer (median, 240 CFU/m(3)). Concentrations of fungi were predominately higher outdoors than indoors, whereas bacteria, endotoxin, and inhalable dust concentrations were highest indoors. Bacteria and endotoxin correlated with the mass of inhalable dust and number of particles. Temperature and air exchange rates were positively associated with fungi and N-acetyl-beta-d-glucosaminidase and negatively with bacteria and the total inflammatory potential. Although temperature, relative humidity, and air exchange rates were significantly associated with several indoor microbial exposures, they could not fully explain the observed seasonal variations when tested in a mixed statistical model. In conclusion, the season significantly affects indoor microbial exposures, which are influenced by temperature, relative humidity, and air exchange rates.

  11. Five percent dextrose maximizes dose delivery of Yttrium-90 resin microspheres and reduces rates of premature stasis compared to sterile water

    PubMed Central

    Koran, Mary Ellen; Stewart, Samantha; Baker, Jennifer C.; Lipnik, Andrew J.; Banovac, Fil; Omary, Reed A.; Brown, Daniel B.

    2016-01-01

    Resin Yttrium-90 (Y90) microspheres have historically been infused using sterile water (H2O). In 2013, recommendations expanded to allow delivery with 5% dextrose in water (D5W). In this retrospective study, we hypothesized that D5W would improve Y90 delivery with a lower incidence of stasis. We reviewed 190 resin Y90 infusions using H2O (n=137) or D5W (n=53). Y90 dosimetry was calculated using the body surface area method. Infusion was halted if intra-arterial stasis was fluoroscopically identified prior to clearing the vial. Differences between H2O and D5W groups were calculated for activity prescription, percentage of cases reaching stasis, and percentage delivery of prescribed activity using z- and t-test comparisons, with α=0.05. Thirty-one of 137 H2O infusions developed stasis compared to 2 of 53 with D5W (z=3.07, p=1.05E-03). D5W also had a significantly higher prescribed activity than H2O [28.2 millicuries (mCi) vs. 20.4 mCi, respectively; t=5.0, p=1.1E-6]. D5W had a higher delivery percentage of the prescribed dose compared to H2O (101.5 vs. 92.7%, respectively; t=3.8, p=1.92E-4). In conclusion, resin microsphere infusion utilizing D5W has a significantly lower rate of stasis than H2O and results in more complete dose delivery. D5W is preferable to H2O for resin microsphere infusion. PMID:28105342

  12. Reference dosimetry at the Australian Synchrotron's imaging and medical beamline using free-air ionization chamber measurements and theoretical predictions of air kerma rate and half value layer

    SciTech Connect

    Crosbie, Jeffrey C.; Rogers, Peter A. W.; Stevenson, Andrew W.; Hall, Christopher J.; Lye, Jessica E.; Nordstroem, Terese; Midgley, Stewart M.; Lewis, Robert A.

    2013-06-15

    Purpose: Novel, preclinical radiotherapy modalities are being developed at synchrotrons around the world, most notably stereotactic synchrotron radiation therapy and microbeam radiotherapy at the European Synchrotron Radiation Facility in Grenoble, France. The imaging and medical beamline (IMBL) at the Australian Synchrotron has recently become available for preclinical radiotherapy and imaging research with clinical trials, a distinct possibility in the coming years. The aim of this present study was to accurately characterize the synchrotron-generated x-ray beam for the purposes of air kerma-based absolute dosimetry. Methods: The authors used a theoretical model of the energy spectrum from the wiggler source and validated this model by comparing the transmission through copper absorbers (0.1-3.0 mm) against real measurements conducted at the beamline. The authors used a low energy free air ionization chamber (LEFAC) from the Australian Radiation Protection and Nuclear Safety Agency and a commercially available free air chamber (ADC-105) for the measurements. The dimensions of these two chambers are different from one another requiring careful consideration of correction factors. Results: Measured and calculated half value layer (HVL) and air kerma rates differed by less than 3% for the LEFAC when the ion chamber readings were corrected for electron energy loss and ion recombination. The agreement between measured and predicted air kerma rates was less satisfactory for the ADC-105 chamber, however. The LEFAC and ADC measurements produced a first half value layer of 0.405 {+-} 0.015 and 0.412 {+-} 0.016 mm Cu, respectively, compared to the theoretical prediction of 0.427 {+-} 0.012 mm Cu. The theoretical model based upon a spectrum calculator derived a mean beam energy of 61.4 keV with a first half value layer of approximately 30 mm in water. Conclusions: The authors showed in this study their ability to verify the predicted air kerma rate and x-ray attenuation

  13. Superhydrophobic materials for drug delivery

    NASA Astrophysics Data System (ADS)

    Yohe, Stefan Thomas

    Superhydrophobicity is a property of material surfaces reflecting the ability to maintain air at the solid-liquid interface when in contact with water. These surfaces have characteristically high apparent contact angles, by definition exceeding 150°, as a result of the composite material-air surface formed under an applied water droplet. Superhydrophobic surfaces were first discovered on naturally occurring substrates, and have subsequently been fabricated in the last several decades to harness these favorable surface properties for a number of emerging applications, including their use in biomedical settings. This work describes fabrication and characterization of superhydrophobic 3D materials, as well as their use as drug delivery devices. Superhydrophobic 3D materials are distinct from 2D superhydrophobic surfaces in that air is maintained not just at the surface of the material, but also within the bulk. When the superhydrophobic 3D materials are submerged in water, water infiltrates slowly and continuously as a new water-air-material interface is formed with controlled displacement of air. Electrospinning and electrospraying are used to fabricate superhydrophobic 3D materials utilizing blends of the biocompatible polymers poly(epsilon-caprolactone) and poly(caprolactone-co-glycerol monostearate) (PGC-C18). PGC-C18 is significantly more hydrophobic than PCL (contact angle of 116° versus 83° for flat materials), and further additions of PGC-C18 into electrospun meshes and electrosprayed coatings affords increased stability of the entrapped air layer. For example, PCL meshes alone (500 mum thick) take 10 days to fully wet, and with 10% or 30% PGC-C18 addition wetting rates are dramatically slowed to 60% wetted by 77 days and 4% by 75 days, respectively. Stability of the superhydrophobic materials can be further probed with a variety of physio-chemical techniques, including pressure, surfactant containing solutions, and solvents of varying surface tension

  14. Authentic Assessment in the Geometry Classroom: Calculating the Classroom Air-Exchange Rate.

    ERIC Educational Resources Information Center

    Erich, David J.

    2002-01-01

    Introduces a room air-exchange activity designed to assess student understanding of the concept of volume. Lists materials for the activity and its procedures. Includes the lesson plan and a student worksheet. (KHR)

  15. Time variations of 222Rn concentration and air exchange rates in a Hungarian cave.

    PubMed

    Nagy, Hedvig Éva; Szabó, Zsuzsanna; Jordán, Gyozo; Szabó, Csaba; Horváth, Akos; Kiss, Attila

    2012-09-01

    A long-term radon concentration monitoring was carried out in the Pál-völgy cave, Budapest, Hungary, for 1.5 years. Our major goal was to determine the time dependence of the radon concentration in the cave to characterise the air exchange and define the most important environmental parameters that influence the radon concentration inside the cave. The radon concentration in the cave air was measured continuously by an AlphaGuard radon monitor, and meteorological parameters outside the cave were collected simultaneously. The air's radon concentration in the cave varied between 104 and 7776 Bq m(-3), the annual average value was 1884±85 Bq m(-3). The summer to winter radon concentration ratio was as high as 21.8. The outside air temperature showed the strongest correlation with the radon concentration in the cave, the correlation coefficient (R) was 0.76.

  16. Western Mojave Desert, Rate of Progress Demonstration; Proposed Approval of California Air Plan Revision

    EPA Pesticide Factsheets

    EPA is proposing to approve a state implementation plan revision submitted by the State of California to meet Clean Air Act requirements applicable to the Western Mojave Desert (WMD) ozone nonattainment area.

  17. Ultra-narrow width air-gap Si FET integrated with micro-fluidic delivery for charge based sensing

    NASA Astrophysics Data System (ADS)

    Gokirmak, Ali; Tiwari, Sandip

    2005-11-01

    An ultra-narrow width silicon field effect transistor (FET) with a suspended gate, integrated with on-chip microfluidic delivery system is described. The device is designed to be used as an FET based sensor for sequencing of DNA, RNA and proteins, by detecting the local charge variations along the chains of these molecules as they are passed between the gate and the channel of the FET in an aqueous solution. A side-gated FET structure is demonstrated with sub-10 nm width, successfully suppressing the electrical leakage currents at the device edges. Side-gated FET structure allows electrostatic confinement of the electrons in the channel for increased spatial resolution.

  18. Air-guided photonic-crystal-fiber pulse-compression delivery of multimegawatt femtosecond laser output for nonlinear-optical imaging and neurosurgery

    NASA Astrophysics Data System (ADS)

    Lanin, Aleksandr A.; Fedotov, Il'ya V.; Sidorov-Biryukov, Dmitrii A.; Doronina-Amitonova, Lyubov V.; Ivashkina, Olga I.; Zots, Marina A.; Sun, Chi-Kuang; Ömer Ilday, F.; Fedotov, Andrei B.; Anokhin, Konstantin V.; Zheltikov, Aleksei M.

    2012-03-01

    Large-core hollow photonic-crystal fibers (PCFs) are shown to enable a fiber-format air-guided delivery of ultrashort infrared laser pulses for neurosurgery and nonlinear-optical imaging. With an appropriate dispersion precompensation, an anomalously dispersive 15-μm-core hollow PCF compresses 510-fs, 1070-nm light pulses to a pulse width of about 110 fs, providing a peak power in excess of 5 MW. The compressed PCF output is employed to induce a local photodisruption of corpus callosum tissues in mouse brain and is used to generate the third harmonic in brain tissues, which is captured by the PCF and delivered to a detector through the PCF cladding.

  19. Comparison of Monoenergetic Photon Organ Dose Rate Coefficients for the Female Stylized and Voxel Phantoms Submerged in Air

    DOE PAGES

    Hiller, Mauritius; Dewji, Shaheen Azim

    2017-02-16

    Dose rate coefficients computed using the International Commission on Radiological Protection (ICRP) reference adult female voxel phantom were compared with values computed using the Oak Ridge National Laboratory (ORNL) adult female stylized phantom in an air submersion exposure geometry. This is a continuation of previous work comparing monoenergetic organ dose rate coefficients for the male adult phantoms. With both the male and female data computed, effective dose rate as defined by ICRP Publication 103 was compared for both phantoms. Organ dose rate coefficients for the female phantom and ratios of organ dose rates for the voxel and stylized phantoms aremore » provided in the energy range from 30 to 5 MeV. Analysis of the contribution of the organs to effective dose is also provided. Lastly, comparison of effective dose rates between the voxel and stylized phantoms was within 8% at 100 keV and is <5% between 200 and 5000 keV.« less

  20. SU-F-BRB-14: Dosimetric Effects at Air- Tissue Boundary Due to Magnetic Field in MR-Guided IMRT/VMAT Delivery for Head and Neck Cancer

    SciTech Connect

    Prior, P; Chen, X; Schultz, C; Li, X

    2015-06-15

    Purpose: The advent of the MR-Linac enables real-time and high soft tissue contrast image guidance in radiation therapy (RT) delivery. Potential hot-spots at air-tissue interfaces, such as the sphenoid sinus, in RT for head and neck cancer (HNC), could potentially occur due to the electron return effect (ERE). In this study, we investigate the dosimetric effects of ERE on the dose distribution at air-tissues interfaces in HNC IMRT treatment planning. Methods: IMRT plans were generated based on planning CT’s acquired for HNC cases (nasopharynx, base of skull and paranasal sinus) using a research planning system (Monaco, v5.09.06, Elekta) employing Monte Carlo dose calculations with or without the presence of a transverse magnetic field (TMF). The dose in the air cavity was calculated in a 1 & 2 mm thick tissue layer, while the dose to the skin was calculated in a 1, 3 and 5 mm thick tissue layer. The maximum dose received in 1 cc volume, D1cc, were collected at different TMF strengths. Plan qualities generated with or without TMF or with increasing TMF were compared in terms of commonly-used dose-volume parameters (DVPs). Results: Variations in DVPs between plans with and without a TMF present were found to be within 5% of the planning CT. The presence of a TMF results in <5% changes in sinus air tissue interface. The largest skin dose differences with and without TMF were found within 1 mm of the skin surface Conclusion: The presence of a TMF results in practically insignificant changes in HNC IMRT plan quality, except for skin dose. Planning optimization with skin DV constraints could reduce the skin doses. This research was partially supported by Elekta Inc. (Crowley, U.K.)

  1. Impact of dose rate on accuracy of intensity modulated radiation therapy plan delivery using the pretreatment portal dosimetry quality assurance and setting up the workflow at hospital levels

    PubMed Central

    Kaviarasu, Karunakaran; Raj, N. Arunai Nambi; Murthy, K. Krishna; Babu, A. Ananda Giri; Prasad, Bhaskar Laxman Durga

    2015-01-01

    The aim of this study was to examine the impact of dose rate on accuracy of intensity modulated radiation therapy (IMRT) plan delivery by comparing the gamma agreement between the calculated and measured portal doses by pretreatment quality assurance (QA) using electronic portal imaging device dosimetry and creating a workflow for the pretreatment IMRT QA at hospital levels. As the improvement in gamma agreement leads to increase in the quality of IMRT treatment delivery, gamma evaluation was carried out for the calculated and the measured portal images for the criteria of 3% dose difference and 3 mm distance-to-agreement (DTA). Three gamma parameters: Maximum gamma, average gamma, and percentage of the field area with a gamma value>1.0 were analyzed. Three gamma index parameters were evaluated for 40 IMRT plans (315 IMRT fields) which were calculated for 400 monitor units (MU)/min dose rate and maximum multileaf collimator (MLC) speed of 2.5 cm/s. Gamma parameters for all 315 fields are within acceptable limits set at our center. Further, to improve the gamma results, we set an action level for this study using the mean and standard deviation (SD) values from the 315 fields studied. Forty out of 315 IMRT fields showed low gamma agreement (gamma parameters>2 SD as per action level of the study). The parameters were recalculated and reanalyzed for the dose rates of 300, 400 and 500 MU/min. Lowering the dose rate helped in getting an enhanced gamma agreement between the calculated and measured portal doses of complicated fields. This may be attributed to the less complex motion of MLC over time and the MU of the field/segment. An IMRT QA work flow was prepared which will help in improving the quality of IMRT delivery. PMID:26865759

  2. To boldly gulp: standard metabolic rate and boldness have context-dependent influences on risk-taking to breathe air in a catfish.

    PubMed

    McKenzie, David J; Belão, Thiago C; Killen, Shaun S; Rantin, F Tadeu

    2015-12-01

    The African sharptooth catfish Clarias gariepinus has bimodal respiration, it has a suprabranchial air-breathing organ alongside substantial gills. We used automated bimodal respirometry to reveal that undisturbed juvenile catfish (N=29) breathed air continuously in normoxia, with a marked diurnal cycle. Air breathing and routine metabolic rate (RMR) increased in darkness when, in the wild, this nocturnal predator forages. Aquatic hypoxia (20% air saturation) greatly increased overall reliance on air breathing. We investigated whether two measures of risk taking to breathe air, namely absolute rates of aerial O2 uptake (ṀO2,air) and the percentage of RMR obtained from air (%ṀO2,air), were influenced by individual standard metabolic rate (SMR) and boldness. In particular, whether any influence varied with resource availability (normoxia versus hypoxia) or relative fear of predation (day versus night). Individual SMR, derived from respirometry, had an overall positive influence on ṀO2,air across all contexts but a positive influence on %ṀO2,air only in hypoxia. Thus, a pervasive effect of SMR on air breathing became most acute in hypoxia, when individuals with higher O2 demand took proportionally more risks. Boldness was estimated as time required to resume air breathing after a fearful stimulus in daylight normoxia (Tres). Although Tres had no overall influence on ṀO2,air or %ṀO2,air, there was a negative relationship between Tres and %ṀO2,air in daylight, in normoxia and hypoxia. There were two Tres response groups, 'bold' phenotypes with Tres below 75 min (N=13) which, in daylight, breathed proportionally more air than 'shy' phenotypes with Tres above 115 min (N=16). Therefore, individual boldness influenced air breathing when fear of predation was high. Thus, individual energy demand and personality did not have parallel influences on the emergent tendency to take risks to obtain a resource; their influences varied in strength with context.

  3. The Air Force Processes for Approving Air Force Life Cycle Management Center Single-Award Indefinite-Delivery Indefinite-Quantity Contracts Need Improvement

    DTIC Science & Technology

    2016-04-29

    Improperly‑ Approved D&F Contract Value FA8540-14-D-0001 Deputy Assistant Secretary (Contracting) August 15, 2011 Yes FA8505-11-D-0006 Deputy...Assistant Secretary (Contracting) September 6, 2011 Yes FA8519-14-D-00021 Military Deputy, Office of the Assistant Secretary of the Air Force...Acquisition) September 2, 2014 No $68,900,414 FA8528-14-D-0015 Senior Procurement Executive April 1, 2014 Yes FA8528-14-D-0023 Senior Procurement

  4. Measurements of air dose rates in and around houses in the Fukushima Prefecture in Japan after the Fukushima accident.

    PubMed

    Matsuda, Norihiro; Mikami, Satoshi; Sato, Tetsuro; Saito, Kimiaki

    2017-01-01

    Measurements of air dose rates for 192 houses in a less contaminated area (<0.5 μSv h(-1)) of the Fukushima Prefecture in Japan were conducted in both living rooms and/or bedrooms using optically stimulated luminescence (OSL) dosimeters and around the houses via a man-borne survey at intervals of several meters. The relation of the two air dose rates (inside and outside) for each house, including the background from natural radionuclides, was divided into several categories, determined by construction materials (light and heavy) and floor number, with the dose reduction factors being expressed as the ratio of the dose inside to that outside the house. For wooden and lightweight steel houses (classed as light), the dose rates inside and outside the houses showed a positive correlation and linear regression with a slope-intercept form due to the natural background, although the degree of correlation was not very high. The regression coefficient, i.e., the average dose reduction factor, was 0.38 on the first floor and 0.49 on the second floor. It was found that the contribution of natural radiation cannot be neglected when we consider dose reduction factors in less contaminated areas. The reductions in indoor dose rates are observed because a patch of ground under each house is not contaminated (this is the so-called uncontaminated effect) since the shielding capability of light construction materials is typically low. For reinforced steel-framed concrete houses (classed as heavy), the dose rates inside the houses did not show a correlation with those outside the houses due to the substantial shielding capability of these materials. The average indoor dose rates were slightly higher than the arithmetic mean value of the outdoor dose rates from the natural background because concrete acts as a source of natural radionuclides. The characteristics of the uncontaminated effect were clarified through Monte Carlo simulations. It was found that there is a great variation

  5. Drying rate and temperature profile for superheated steam vacuum drying and moist air drying of softwood lumber

    SciTech Connect

    Pang, S.; Dakin, M.

    1999-07-01

    Two charges of green radiata pine sapwood lumber were dried, ether using superheated steam under vacuum (90 C, 0.2 bar abs.) or conventionally using hot moist air (90/60 C). Due to low density of the drying medium under vacuum, the circulation velocity used was 10 m/s for superheated steam drying and 5.0 m/s for moist air drying, and in both cases, the flow was unidirectional. In drying, stack drying rate and wood temperatures were measured to examine the differences between the superheated steam drying and drying using hot moist air. The experimental results have shown that the stack edge board in superheated steam drying dried faster than in the hot moist air drying. Once again due to the low density of the steam under vacuum, a prolonged maximum temperature drop across load (TDAL) was observed in the superheated steam drying, however, the whole stack dried slower and the final moisture content distribution was more variable than for conventional hot moist air drying.

  6. Air Vehicle Integration and Technology Research (AVIATR). Delivery Order 0013: Nonlinear, Low-Order/Reduced-Order Modeling Applications and Demonstration

    DTIC Science & Technology

    2011-12-01

    distribution for Ti panel in exhaust flow of T-58 jet engine ................ 72 Figure 93 – Temperature distribution for Ti panel in exhaust flow of T-58 jet...image max temperature 350°F, no air flow ........................................................ 95 Figure 129 – IR image at max temperature 500°F, Test...correlation degrading with distance (separated flow , exhaust impinged flow ). Figure 5 – Acoustic noise sources Another important aspect of the acoustic

  7. Characteristics and verification of a car-borne survey system for dose rates in air: KURAMA-II.

    PubMed

    Tsuda, S; Yoshida, T; Tsutsumi, M; Saito, K

    2015-01-01

    The car-borne survey system KURAMA-II, developed by the Kyoto University Research Reactor Institute, has been used for air dose rate mapping after the Fukushima Dai-ichi Nuclear Power Plant accident. KURAMA-II consists of a CsI(Tl) scintillation detector, a GPS device, and a control device for data processing. The dose rates monitored by KURAMA-II are based on the G(E) function (spectrum-dose conversion operator), which can precisely calculate dose rates from measured pulse-height distribution even if the energy spectrum changes significantly. The characteristics of KURAMA-II have been investigated with particular consideration to the reliability of the calculated G(E) function, dose rate dependence, statistical fluctuation, angular dependence, and energy dependence. The results indicate that 100 units of KURAMA-II systems have acceptable quality for mass monitoring of dose rates in the environment.

  8. Deconvolution of insulin secretion, insulin hepatic extraction post-hepatic delivery rates and sensitivity during 24-hour standardized meals: time course of glucose homeostasis in leptin replacement treatment.

    PubMed

    Andreev, V P; Paz-Filho, G; Wong, M-L; Licinio, J

    2009-02-01

    Minimally invasive methodology, mathematical model, and software for analysis of glucose homeostasis by deconvolution of insulin secretion, hepatic extraction, post-hepatic delivery, and sensitivity from 24-hour standardized meals test have been developed and illustrated by the study of glucose homeostasis of a genetically based leptin-deficient patient before and after leptin replacement treatment. The only genetically leptin-deficient adult man identified in the world was treated for 24 months with recombinant methionyl human leptin. Blood was collected every 7 minutes for 24 hours, with standardized meals consumed during the 4 visits: at baseline, one-week, 18-months, and 24-months after initiation of the treatment. Concentrations of insulin, C-peptide, and plasma glucose were measured. Insulin secretion was obtained by deconvolution of C-peptide data. Hepatic insulin extraction was determined based on our modifications of the insulin kinetics model . Insulin sensitivity for each of the four meals was calculated by using the minimal glucose model approach. Hepatic extraction of insulin was the first element of glucose homeostasis to respond to leptin replacement treatment and increased 2-fold after one week of treatment. Insulin secretion and delivery rates decreased more than 2-fold and insulin sensitivity increased 10-fold after 24 months of treatment. Computer programs for analysis of 24-hour insulin secretion, extraction, delivery, and action are available upon request.

  9. California residential indoor air quality study. Volume 2. Carbon monoxide and air exchange rate: A univariate and multivariate analysis. Topical report

    SciTech Connect

    Colome, S.D.; Wilson, A.L.; Tian, Y.

    1994-07-01

    This second volume provides a systematic evaluation of the data set focusing on the relationships of the recorded parameters with the following four outcome measures: indoor 48-hour average CO; net 48-hour average indoor minus outdoor CO; air exchange rates; and maximum 8-hour average indoor CO. Over 350 variables were measured and/or recorded for each house in the pilot study. These parameters included the concentrations of pollutants of interest (CO, benzene, NO2, toluene, radon, formaldehyde, and methane), housing characteristics (e.g., cooking fuel, burner adjustments, proper venting) and occupant practices (e.g., cigarette smoking, heating with the range/oven).

  10. Regional Contrasts of the Warming Rate over Land Significantly Depend on the Calculation Methods of Mean Air Temperature.

    PubMed

    Wang, Kaicun; Zhou, Chunlüe

    2015-07-22

    Global analyses of surface mean air temperature (T(m)) are key datasets for climate change studies and provide fundamental evidences for global warming. However, the causes of regional contrasts in the warming rate revealed by such datasets, i.e., enhanced warming rates over the northern high latitudes and the "warming hole" over the central U.S., are still under debate. Here we show these regional contrasts depend on the calculation methods of T(m). Existing global analyses calculate T(m) from daily minimum and maximum temperatures (T2). We found that T2 has a significant standard deviation error of 0.23 °C/decade in depicting the regional warming rate from 2000 to 2013 but can be reduced by two-thirds using T(m) calculated from observations at four specific times (T4), which samples diurnal cycle of land surface air temperature more often. From 1973 to 1997, compared with T4, T2 significantly underestimated the warming rate over the central U.S. and overestimated the warming rate over the northern high latitudes. The ratio of the warming rate over China to that over the U.S. reduces from 2.3 by T2 to 1.4 by T4. This study shows that the studies of regional warming can be substantially improved by T4 instead of T2.

  11. Nanosecond discharge in air at atmospheric pressure as an x-ray source with high pulse repetition rates

    NASA Astrophysics Data System (ADS)

    Tarasenko, Victor F.

    2006-02-01

    The properties of x-ray radiation and runaway electrons produced using a nanosecond volume discharge are examined. X-ray radiation at a pulse repetition rate of 3kHz was obtained time in a gas diode filled with air at atmospheric pressure. The current pulse width (FWHM) for runaway electrons generated in the gas diode was ˜100ps. A prepulse was observed on an oscilloscope trace of the main runaway electron beam current.

  12. Nanosecond discharge in air at atmospheric pressure as an x-ray source with high pulse repetition rates

    SciTech Connect

    Tarasenko, Victor F.

    2006-02-20

    The properties of x-ray radiation and runaway electrons produced using a nanosecond volume discharge are examined. X-ray radiation at a pulse repetition rate of 3 kHz was obtained time in a gas diode filled with air at atmospheric pressure. The current pulse width (FWHM) for runaway electrons generated in the gas diode was {approx}100 ps. A prepulse was observed on an oscilloscope trace of the main runaway electron beam current.

  13. Elementary stage rate coefficients of heterogeneous catalytic recombination of dissociated air on thermal protective surfaces from ab initio approach

    NASA Astrophysics Data System (ADS)

    Buchachenko, A. A.; Kroupnov, A. A.; Kovalev, V. L.

    2015-08-01

    Elementary stage rate coefficients of the full system of kinetic equations describing heterogeneous catalytic recombination of the dissociated air on the surfaces of thermal protective ceramic coatings of β-cristobalite and α-Al2O3 are determined using the quantum-mechanical calculations within the framework of cluster models and literature data. Both the impact and associative recombination processes of adsorbed oxygen and nitrogen atoms are taken into account.

  14. THE EFFECT OF SALINITY ON RATES OF ELEMENTAL MERCURY AIR/WATER EXCHANGE

    EPA Science Inventory

    The U.S. EPA laboratory in Athens, Georgia i spursuing the goal of developing a model for describing toxicant vapor phase air/water exchange under all relevant environmental conditions. To date, the two-layer exchange model (suitable for low wind speed conditions) has been modif...

  15. THE ROLE OF AQUEOUS THIN FILM EVAPORATIVE COOLING ON RATES OF ELEMENTAL MERCURY AIR-WATER EXCHANGE UNDER TEMPERATURE DISEQUILIBRIUM CONDITIONS

    EPA Science Inventory

    The technical conununity has only recently addressed the role of atmospheric temperature variations on rates of air-water vapor phase toxicant exchange. The technical literature has documented that: 1) day time rates of elemental mercury vapor phase air-water exchange can exceed ...

  16. Determination of dispersion parameters for oxidizing air and the oxidation rate of calcium sulfites in a pilot desulfurization plant

    SciTech Connect

    Burenkov, D.K.; Derevich, I.V.; Rzaev, A.I.

    1995-10-01

    In the effort to remove sulfur oxides from waste gases, the widest use is gained by desulfurization plants based on wet collection of sulfur dioxide in empty absorbers in which a limestone-gypsum suspension is sprayed, with gypsum being produced as a commodity product. Dispersion of oxidizing air in a model liquid and the oxidation rate of calcium sulfites in a suspension contained in the sump of a pilot desulfurization plant absorber are studied experimentally. Flow velocities, bubble trajectories, and oxidation rates were determined and are presented.

  17. Production and Characterization of High Repetition Rate Terahertz Radiation in Femtosecond-Laser-Induced Air Plasma

    DTIC Science & Technology

    2009-03-01

    and plasma signal. The air plasma intensity was measured using a 40 kHz ultrasonic transducer, while the terahertz radiation was measured by a... calibrate the time axis of the streak camera ................................................... 28 8. Processed data used to calibrate the time axis of...field can be measured 5 directly, but is difficult to manipulate and requires bulky waveguides. However, in optics, radiation is viewed as light

  18. Indoor air pollutants, ventilation rate determinants and potential control strategies in Chinese dwellings: A literature review.

    PubMed

    Ye, Wei; Zhang, Xu; Gao, Jun; Cao, Guangyu; Zhou, Xiang; Su, Xing

    2017-05-15

    After nearly twenty years of rapid modernization and urbanization in China, huge achievements have transformed the daily lives of the Chinese people. However, unprecedented environmental consequences in both indoor and outdoor environments have accompanied this progress and have triggered public awareness and demands for improved living standards, especially in residential environments. Indoor pollution data measured for >7000 dwellings (approximately 1/3 were newly decorated and were tested for volatile organic compound (VOC) measurements, while the rest were tested for particles, phthalates and other semi-volatile organic compounds (SVOCs), moisture/mold, inorganic gases and radon) in China within the last ten years were reviewed, summarized and compared with indoor concentration recommendations based on sensory or health end-points. Ubiquitous pollutants that exceed the concentration recommendations, including particulate matter, formaldehyde, benzene and other VOCs, moisture/mold, inorganic gases and radon, were found, indicating a common indoor air quality (IAQ) issue in Chinese dwellings. With very little prevention, oral, inhalation and dermal exposure to those pollutants at unhealthy concentration levels is almost inevitable. CO2, VOCs, humidity and radon can serve as ventilation determinants, each with different ventilation demands and strategies, at typical occupant densities in China; and particle reduction should be a prerequisite for determining ventilation requirements. Two directional ventilation modes would have profound impacts on improving IAQ for Chinese residences are: 1) natural (or window) ventilation with an air cleaner and 2) mechanical ventilation with an air filtration unit, these two modes were reviewed and compared for their applicability and advantages and disadvantages for reducing human exposure to indoor air pollutants. In general, mode 2 can more reliably ensure good IAQ for occupants; while mode 1 is more applicable due to its low

  19. 48 CFR 1552.216-73 - Fixed rates for services-indefinite delivery/indefinite quantity contract.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Fixed rates for services... Regulations System ENVIRONMENTAL PROTECTION AGENCY CLAUSES AND FORMS SOLICITATION PROVISIONS AND CONTRACT CLAUSES Texts of Provisions and Clauses 1552.216-73 Fixed rates for services—indefinite...

  20. 48 CFR 1552.216-73 - Fixed rates for services-indefinite delivery/indefinite quantity contract.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 6 2012-10-01 2012-10-01 false Fixed rates for services... Regulations System ENVIRONMENTAL PROTECTION AGENCY CLAUSES AND FORMS SOLICITATION PROVISIONS AND CONTRACT CLAUSES Texts of Provisions and Clauses 1552.216-73 Fixed rates for services—indefinite...

  1. 48 CFR 1552.216-73 - Fixed rates for services-indefinite delivery/indefinite quantity contract.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 6 2014-10-01 2014-10-01 false Fixed rates for services... Regulations System ENVIRONMENTAL PROTECTION AGENCY CLAUSES AND FORMS SOLICITATION PROVISIONS AND CONTRACT CLAUSES Texts of Provisions and Clauses 1552.216-73 Fixed rates for services—indefinite...

  2. A neural network based optimization system provides on-line coal fired furnace air flow balancing for heat rate improvement and NO{sub x} reduction

    SciTech Connect

    Radl, B.J.; Roland, W. Jr.

    1995-12-31

    The optimization system provides on-line, real-time air flow balancing without extensive testing or large complex physical models. NO{sub x} emissions and unit heat rate are very sensitive to air distribution and turbulence in the combustion zone. These issues are continuously changing due to ambient conditions, coal quality and the condition of plant equipment. This report discusses applying on-line, real-time and neural network to adjust secondary air flow and overfire air flow to reduce NO{sub x} and improve heat rate on various coal fired boiler designs.

  3. Influence of inspiratory flow rate, particle size, and airway caliber on aerosolized drug delivery to the lung.

    PubMed

    Dolovich, M A

    2000-06-01

    A number of studies in the literature support the use of fine aerosols of drug, inhaled at low IFRs to target peripheral airways, with the objective of improving clinical responses to inhaled therapy (Fig. 8). Attempts have been made to separate response due to changes in total administered dose or the surface concentration of the dose from response due to changes in site of deposition--both are affected by the particle size of the aerosol, with IFR additionally influencing the latter. The tools for measuring dose and distribution have improved over the last 10-15 years, and thus we should expect greater accuracy in these measurements for assessing drug delivery to the lung. There are still issues, though, in producing radiolabeled (99m)technetium aerosols that are precise markers for the pharmaceutical product being tested and in quantitating absolute doses deposited in the lung. PET isotopes may provide the means for directly labelling a drug and perhaps can offer an alternative for making these measurements in the future, but deposition measurements should not be used in isolation; protocols should incorporate clinical tests to provide parallel therapeutic data in response to inhalation of the drug by the various patient populations being studied.

  4. Oxidation rate of nuclear-grade graphite IG-110 in the kinetic regime for VHTR air ingress accident scenarios

    NASA Astrophysics Data System (ADS)

    Lee, Jo Jo; Ghosh, Tushar K.; Loyalka, Sudarshan K.

    2014-03-01

    The oxidation rates of nuclear-grade graphite IG-110 in the kinetically-controlled temperature regime of graphite oxidation were predicted and compared in Very High Temperature Reactor air ingress accident scenarios. The oxidative mass loss of graphite was measured thermogravimetrically from 873 to 1873 K in 100% air (21 mol%). The activation energy was found to be 222.07 kJ/mol, and the order of reaction with respect to oxygen concentration is 0.76. The surfaces of the samples were characterized by Scanning Electron Microscopy, Energy Dispersive Spectroscopy, Fourier Transform Infrared Spectroscopy and X-ray Photoelectron Spectroscopy before and after oxidation. These results are compared with those available in the literature, and our recently reported results for NBG-18 nuclear-grade graphite using the same technique.

  5. Relationships between ozone photolysis rates and peroxy radical concentrations in clean marine air over the Southern Ocean

    NASA Astrophysics Data System (ADS)

    Penkett, S. A.; Monks, P. S.; Carpenter, L. J.; Clemitshaw, K. C.; Ayers, G. P.; Gillett, R. W.; Galbally, I. E.; Meyer, C. P.

    1997-06-01

    Measurements of the sum of inorganic and organic peroxy radicals (RO2) and photolysis rate coefficients J(NO2) and J(O1D) have been made at Cape Grim, Tasmania in the course of a comprehensive experiment which studied photochemistry in the unpolluted marine boundary layer. The SOAPEX (Southern Ocean Atmospheric Photochemistry Experiment) campaign included measurements of ozone, peroxides, nitrogen oxides, water vapor, and many other parameters. This first full length paper concerned with the experiment focuses on the types of relationships observed between peroxy radicals and J(NO2), J(O1D) and √[J(O1D)] in different air masses in which ozone is either produced or destroyed by photochemistry. It was found that in baseline air with ozone loss, RO2 was proportional to √[J(O1D)], whereas in more polluted air RO2 was proportional to J(O1D). Simple algorithms were derived to explain these relationships and also to calculate the concentrations of OH radicals in baseline air from the instantaneous RO2 concentrations. The signal to noise ratio of the peroxy radical measurements was up to 10 for 1-min values and much higher than in other previous deployments of the instrument in the northern hemisphere, leading to the confident determination of the relationships between RO2 and J(O1D) in different conditions. The absolute concentration Of RO2 determined in these experiments is in some doubt, but this does not affect our conclusions concerned either with the behavior of peroxy radicals with changing light levels or with the concentrations of OH calculated from RO2. The results provide confidence that the level of understanding of the photochemistry of ozone leading to the production of peroxide via recombination of peroxy radicals in clean air environments is well advanced.

  6. SU-E-T-375: Evaluation of a MapCHECK2(tm) Planar 2-D Diode Array for High-Dose-Rate Brachytherapy Treatment Delivery Verifications

    SciTech Connect

    Macey, N; Siebert, M; Shvydka, D; Parsai, E

    2015-06-15

    Purpose: Despite improvements of HDR brachytherapy delivery systems, verification of source position is still typically based on the length of the wire reeled out relative to the parked position. Yet, the majority of errors leading to medical events in HDR treatments continue to be classified as missed targets or wrong treatment sites. We investigate the feasibility of using dose maps acquired with a two-dimensional diode array to independently verify the source locations, dwell times, and dose during an HDR treatment. Methods: Custom correction factors were integrated into frame-by-frame raw counts recorded for a Varian VariSource™ HDR afterloader Ir-192 source located at various distances in air and in solid water from a MapCHECK2™ diode array. The resultant corrected counts were analyzed to determine the dwell position locations and doses delivered. The local maxima of polynomial equations fitted to the extracted dwell dose profiles provided the X and Y coordinates while the distance to the source was determined from evaluation of the full width at half maximum (FWHM). To verify the approach, the experiment was repeated as the source was moved through dwell positions at various distances along an inclined plane, mimicking a vaginal cylinder treatment. Results: Dose map analysis was utilized to provide the coordinates of the source and dose delivered over each dwell position. The accuracy in determining source dwell positions was found to be +/−1.0 mm of the preset values, and doses within +/−3% of those calculated by the BrachyVision™ treatment planning system for all measured distances. Conclusion: Frame-by-frame data furnished by a 2 -D diode array can be used to verify the dwell positions and doses delivered by the HDR source over the course of treatment. Our studies have verified that measurements provided by the MapCHECK2™ can be used as a routine QA tool for HDR treatment delivery verification.

  7. Magnetic Nanodrug Delivery Through the Mucus Layer of Air-Liquid Interface Cultured Primary Normal Human Tracheobronchial Epithelial Cells.

    PubMed

    Economou, E C; Marinelli, S; Smith, M C; Routt, A A; Kravets, V V; Chu, H W; Spendier, K; Celinski, Z J

    2016-09-01

    Superparamagnetic iron oxide (Fe3O4) and highly anisotropic barium hexaferrite (BaFe12O19) nanoparticles were coated with an anti-inflammatory drug and magnetically transported through mucus produced by primary human airway epithelial cells. Using wet planetary ball milling, dl-2-amino-3-phosphonopropionic acid-coated BaFe12O19 nano-particles (BaNPs) of 1-100 nm in diameter were prepared in water. BaNPs and conventional 20-30-nm Fe3O4 nanoparticles (FeNPs) were then encased in a polymer (PLGA) loaded with dexamethasone (Dex) and tagged for imaging. PLGA-Dex-coated BaNPs and FeNPs were characterized using dynamic light scattering (DLS), transmission electron microscopy (TEM), and superconducting quantum interference device (SQUID) magnetometry. Both PLGA-Dex-coated BaNPs and FeNPs were transferred to the surface of a ~100-μm thick mucus layer of air-liquid interface cultured primary normal human tracheobronchial epithelial (NHTE) cells. Within 30 min, the nanoparticles were pulled successfully through the mucus layer by a permanent neodymium magnet. The penetration time of the nanomedicine was monitored using confocal microscopy and tailored by varying the thickness of the PLGA-Dex coating around the particles.

  8. Magnetic Nanodrug Delivery Through the Mucus Layer of Air-Liquid Interface Cultured Primary Normal Human Tracheobronchial Epithelial Cells

    PubMed Central

    Economou, E. C.; Marinelli, S.; Smith, M. C.; Routt, A. A.; Kravets, V. V.; Chu, H. W.; Spendier, K.; Celinski, Z. J.

    2016-01-01

    Superparamagnetic iron oxide (Fe3O4) and highly anisotropic barium hexaferrite (BaFe12O19) nanoparticles were coated with an anti-inflammatory drug and magnetically transported through mucus produced by primary human airway epithelial cells. Using wet planetary ball milling, dl-2-amino-3-phosphonopropionic acid-coated BaFe12O19 nano-particles (BaNPs) of 1–100 nm in diameter were prepared in water. BaNPs and conventional 20–30-nm Fe3O4 nanoparticles (FeNPs) were then encased in a polymer (PLGA) loaded with dexamethasone (Dex) and tagged for imaging. PLGA-Dex-coated BaNPs and FeNPs were characterized using dynamic light scattering (DLS), transmission electron microscopy (TEM), and superconducting quantum interference device (SQUID) magnetometry. Both PLGA-Dex-coated BaNPs and FeNPs were transferred to the surface of a ~100-μm thick mucus layer of air-liquid interface cultured primary normal human tracheobronchial epithelial (NHTE) cells. Within 30 min, the nanoparticles were pulled successfully through the mucus layer by a permanent neodymium magnet. The penetration time of the nanomedicine was monitored using confocal microscopy and tailored by varying the thickness of the PLGA-Dex coating around the particles. PMID:27774374

  9. Air-To-Water Heat Pumps with Radiant Delivery in Low Load Homes: Tucson, Arizona and Chico, California (Fact Sheet)

    SciTech Connect

    Not Available

    2013-11-01

    Space conditioning represents nearly 50% of average residential household energy consumption, highlighting the need to identify alternative cost-effective, energy-efficient cooling and heating strategies. As homes are better built, there is an increasing need for strategies that are particularly well suited for high performance, low load homes. ARBI researchers worked with two test homes in hot-dry climates to evaluate the in-situ performance of air-to-water heat pump (AWHP) systems, an energy efficient space conditioning solution designed to cost-effectively provide comfort in homes with efficient, safe, and durable operation. Two monitoring projects of test houses in hot-dry climates were initiated in 2010 to test this system. Both systems were fully instrumented and have been monitored over one year to capture complete performance data over the cooling and heating seasons. Results are used to quantify energy savings, cost-effectiveness, and system performance using different operating modes and strategies. A calibrated TRNSYS model was developed and used to evaluate performance in various climate regions. This strategy is most effective in tight, insulated homes with high levels of thermal mass (i.e. exposed slab floors).

  10. Crash Rates of Scheduled Commuter and Air Carrier Flights Before and After a Regulatory Change

    PubMed Central

    Baker, Susan P.; Groff, Loren; Haaland, Wren; Qiang, Yandong; Rebok, George W.; Li, Guohua

    2010-01-01

    Introduction In 1997, in an effort to reduce the crash rate of scheduled commuter flights, the FAA required aircraft with 10–30 passenger seats to operate under stricter rules. Training and other requirements of 14 CFR Part 121 rules were applied to these midsize commuters, which previously had operated under the less strict Part 135 rules. Published crash rates obscured changes related to aircraft size. This research was undertaken to determine whether the rule change affected crash rates of aircraft with 10–30 passenger seats. Method We determined the number of passenger seats on each Part 135 or Part 121 aircraft that crashed between 1983 and 2007. For aircraft with < 10, 10–30, and > 30 seats, we estimated the numbers of departures and crash rates, adjusting for changes in total departures and numbers of in-service aircraft. Results The Part 135 crash rate tripled in 1997 when commuters with 10–30 seats were excluded, reflecting the administrative change. However, the crash rate of aircraft with 10–30 passenger seats began to decline 4 yr before the rule change; thereafter, their rate was lower than for larger aircraft. The fleet size of aircraft with 10–30 passenger seats increased from 1983 to 1997, then declined as they were replaced with larger aircraft in response to the rule change. Discussion No effect of the rule change on crash rates of 10–30-seat aircraft was apparent. The decline in their crash rates began before the rule change and may have been related to the 1992 requirement for ground proximity warning devices. PMID:19378909

  11. Distribution and Rate of Microbial Processes in an Ammonia-Loaded Air Filter Biofilm▿

    PubMed Central

    Juhler, Susanne; Revsbech, Niels Peter; Schramm, Andreas; Herrmann, Martina; Ottosen, Lars D. M.; Nielsen, Lars Peter

    2009-01-01

    The in situ activity and distribution of heterotrophic and nitrifying bacteria and their potential interactions were investigated in a full-scale, two-section, trickling filter designed for biological degradation of volatile organics and NH3 in ventilation air from pig farms. The filter biofilm was investigated by microsensor analysis, fluorescence in situ hybridization, quantitative PCR, and batch incubation activity measurements. In situ aerobic activity showed a significant decrease through the filter, while the distribution of ammonia-oxidizing bacteria (AOB) was highly skewed toward the filter outlet. Nitrite oxidation was not detected during most of the experimental period, and the AOB activity therefore resulted in NO2−, accumulation, with concentrations often exceeding 100 mM at the filter inlet. The restriction of AOB to the outlet section of the filter was explained by both competition with heterotrophic bacteria for O2 and inhibition by the protonated form of NO2−, HNO2. Product inhibition of AOB growth could explain why this type of filter tends to emit air with a rather constant NH3 concentration irrespective of variations in inlet concentration and airflow. PMID:19363071

  12. Low air exchange rate causes high indoor radon concentration in energy-efficient buildings.

    PubMed

    Vasilyev, A V; Yarmoshenko, I V; Zhukovsky, M V

    2015-06-01

    Since 1995, requirements on energy-efficient building construction were established in Russian Building Codes. In the course of time, utilisation of such technologies became prevailing, especially in multi-storey building construction. According to the results of radon survey in buildings constructed meeting new requirements on energy efficiency, radon concentration exceeds the average level in early-constructed buildings. Preponderance of the diffusion mechanism of radon entry in modern multi-storey buildings has been experimentally established. The experimental technique of the assessment of ventilation rate in dwellings under real conditions was developed. Based on estimates of average ventilation rate, it was approved that measures to increase energy efficiency lead to reduction in ventilation rate and accumulation of higher radon concentrations indoors. Obtained ventilation rate values have to be considered as extremely low.

  13. Embedded computer controlled premixing inline injection system for air-assisted variable-rate sprayers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Improvements to reduce chemical waste and environmental pollution for variable-rate sprayers used in orchards and ornamental nurseries require inline injection techniques. A microprocessor controlled premixing inline injection system implementing a ceramic piston chemical metering pump and two small...

  14. The Sky is Falling: An air deposition/stormwater runoff model simulating the pathways of five heavy metals from their status as mobile and stack exhaust constituents to their delivery to the Elizabeth River

    SciTech Connect

    Barrett-McDaniels, J.; Barrett, M.

    1997-12-31

    Recent studies by the Environmental Protection Agency (EPA) indicate that air emissions contribute a major portion of the total loading of toxic metals to the waters of the Chesapeake Bay and its tributaries. According to the Chesapeake Executive Council of the interstate Chesapeake Bay Program, five of these metals, cadmium, chromium, copper, lead, and zinc, have been observed to have a negative impact on the waters of the Elizabeth River, which is within the Chesapeake Bay watershed. In order to better define the sources and processes which contribute to concentrations of these metals in the Elizabeth River, this analysis simulates the pathway of these metals from their status as mobile and stack exhaust constituents to their delivery to the river. EPA`s ISCST3 model was used to predict deposition loading on the Elizabeth River water and watershed surfaces, using regional annual meteorological data. Air emissions input to the ISCST3 model were derived from stationary and mobile sources: stationary source emissions were estimated using Virginia Department of Environmental Quality inventories and EPA-approved emissions factors for major sources with the potential to impact the watershed, while mobile source emissions were estimated using traffic volumes provided by the Department of Transportation and EPA-approved emissions factors. EPA`s SWMM model was then used to predict maximum short term and average annual build up and wash off rates for these metals using recorded rainfall data and existing land use and impervious cover for the watershed. The results are compared to water quality monitoring data from the municipal NPDES stormwater wet weather monitoring permit program.

  15. An accurate derivation of the air dose-rate and the deposition concentration distribution by aerial monitoring in a low level contaminated area

    NASA Astrophysics Data System (ADS)

    Nishizawa, Yukiyasu; Sugita, Takeshi; Sanada, Yukihisa; Torii, Tatsuo

    2015-04-01

    Since 2011, MEXT (Ministry of Education, Culture, Sports, Science and Technology, Japan) have been conducting aerial monitoring to investigate the distribution of radioactive cesium dispersed into the atmosphere after the accident at the Fukushima Dai-ichi Nuclear Power Plant (FDNPP), Tokyo Electric Power Company. Distribution maps of the air dose-rate at 1 m above the ground and the radioactive cesium deposition concentration on the ground are prepared using spectrum obtained by aerial monitoring. The radioactive cesium deposition is derived from its dose rate, which is calculated by excluding the dose rate of the background radiation due to natural radionuclides from the air dose-rate at 1 m above the ground. The first step of the current method of calculating the dose rate due to natural radionuclides is calculate the ratio of the total count rate of areas where no radioactive cesium is detected and the count rate of regions with energy levels of 1,400 keV or higher (BG-Index). Next, calculate the air dose rate of radioactive cesium by multiplying the BG-Index and the integrated count rate of 1,400 keV or higher for the area where the radioactive cesium is distributed. In high dose-rate areas, however, the count rate of the 1,365-keV peak of Cs-134, though small, is included in the integrated count rate of 1,400 keV or higher, which could cause an overestimation of the air dose rate of natural radionuclides. We developed a method for accurately evaluating the distribution maps of natural air dose-rate by excluding the effect of radioactive cesium, even in contaminated areas, and obtained the accurate air dose-rate map attributed the radioactive cesium deposition on the ground. Furthermore, the natural dose-rate distribution throughout Japan has been obtained by this method.

  16. The effects of air temperature on office workers' well-being, workload and productivity-evaluated with subjective ratings.

    PubMed

    Lan, Li; Lian, Zhiwei; Pan, Li

    2010-12-01

    Productivity bears a close relationship to the indoor environmental quality (IEQ), but how to evaluate office worker's productivity remains to be a challenge for ergonomists. In this study, the effect of indoor air temperature (17 °C, 21 °C, and 28 °C) on productivity was investigated with 21 volunteered participants in the laboratory experiment. Participants performed computerized neurobehavioral tests during exposure in the lab; their physiological parameters including heart rate variation (HRV) and electroencephalograph (EEG) were also measured. Several subjective rating scales were used to tap participant's emotion, well-being, motivation and the workload imposed by tasks. It was found that the warm discomfort negatively affected participants' well-being and increased the ratio of low frequency (LF) to high frequency (HF) of HRV. In the moderately uncomfortable environment, the workload imposed by tasks increased and participants had to exert more effort to maintain their performance and they also had lower motivation to do work. The results indicate that thermal discomfort caused by high or low air temperature had negative influence on office workers' productivity and the subjective rating scales were useful supplements of neurobehavioral performance measures when evaluating the effects of IEQ on productivity.

  17. Indoor air quality, air exchange rates, and radioactivity in new built temporary houses following the Great East Japan Earthquake in Minamisoma, Fukushima.

    PubMed

    Shinohara, N; Tokumura, M; Kazama, M; Yoshino, H; Ochiai, S; Mizukoshi, A

    2013-08-01

    This study measured air exchange rates, indoor concentrations of aldehydes and volatile organic compounds (VOCs), and radioactivity levels at 19 temporary houses in different temporary housing estate constructed in Minamisoma City following the Great East Japan Earthquake. The 19 surveyed houses represented all of the companies assigned to construct temporary houses in that Minamisoma City. Data were collected shortly after construction and before occupation, from August 2011 to January 2012. Mean air exchange rates in the temporary houses were 0.28/h, with no variation according to housing types and construction date. Mean indoor concentrations of formaldehyde, acetaldehyde, toluene, ethylbenzene, m/p-xylene, o-xylene, styrene, p-dichlorobenzene, tetradecane, and total VOCs (TVOCs) were 29.2, 72.7, 14.6, 6.35, 3.05, 1.81, 7.29, 14.3, 8.32, and 901 μg/m(3), respectively. The levels of acetaldehyde and TVOCs exceeded the indoor guideline (48 μg/m(3)) and interim target (400 μg/m(3)) in more than half of the 31 rooms tested. In addition to guideline chemicals, terpenes (α-pinene and d-limonene) and acetic esters (butyl acetate and ethyl acetate) were often detected in these houses. The indoor radiation levels measured by a Geiger-Müller tube (Mean: 0.22 μSv/h) were lower than those recorded outdoors (Mean: 0.42 μSv/h), although the shielding effect of the houses was less than for other types of buildings.

  18. Improving snow process modeling with satellite-based estimation of near-surface-air-temperature lapse rate

    NASA Astrophysics Data System (ADS)

    Wang, Lei; Sun, Litao; Shrestha, Maheswor; Li, Xiuping; Liu, Wenbin; Zhou, Jing; Yang, Kun; Lu, Hui; Chen, Deliang

    2016-10-01

    In distributed hydrological modeling, surface air temperature (Tair) is of great importance in simulating cold region processes, while the near-surface-air-temperature lapse rate (NLR) is crucial to prepare Tair (when interpolating Tair from site observations to model grids). In this study, a distributed biosphere hydrological model with improved snow physics (WEB-DHM-S) was rigorously evaluated in a typical cold, large river basin (e.g., the upper Yellow River basin), given a mean monthly NLRs. Based on the validated model, we have examined the influence of the NLR on the simulated snow processes and streamflows. We found that the NLR has a large effect on the simulated streamflows, with a maximum difference of greater than 24% among the various scenarios for NLRs considered. To supplement the insufficient number of monitoring sites for near-surface-air-temperature at developing/undeveloped mountain regions, the nighttime Moderate Resolution Imaging Spectroradiometer land surface temperature is used as an alternative to derive the approximate NLR at a finer spatial scale (e.g., at different elevation bands, different land covers, different aspects, and different snow conditions). Using satellite-based estimation of NLR, the modeling of snow processes has been greatly refined. Results show that both the determination of rainfall/snowfall and the snowpack process were significantly improved, contributing to a reduced summer evapotranspiration and thus an improved streamflow simulation.

  19. Oxidation rate of graphitic matrix material in the kinetic regime for VHTR air ingress accident scenarios

    NASA Astrophysics Data System (ADS)

    Lee, Jo Jo; Ghosh, Tushar K.; Loyalka, Sudarshan K.

    2014-08-01

    Data on oxidation rates of matrix-grade graphite in the kinetically-controlled temperature regime of graphite oxidation are needed for safety analysis of High Temperature Gas Cooled Reactors and Very High Temperature Reactors. In this work, the oxidation rate of graphitic matrix material GKrS was measured thermogravimetrically for various oxygen concentrations and with temperatures from 873 to 1873 K. A semi-empirical Arrhenius rate equation was also developed for this temperature range. The activation energy of the graphitic material is found to be about 111.5 kJ/mol. The order of reaction was found to be about 0.89. The surface of oxidized GKrS was characterized by Scanning Electron Microscopy, Electron Dispersive Spectroscopy, Fourier Transform Infrared Spectroscopy and X-ray Photoelectron Spectroscopy.

  20. Identifying Housing and Meteorological Conditions Influencing Residential Air Exchange Rates in the DEARS and RIOPA Studies: Development of Distributions for Human Exposure Modeling

    EPA Science Inventory

    Appropriate prediction of residential air exchange rate (AER) is important for estimating human exposures in the residential microenvironment, as AER drives the infiltration of outdoor-generated air pollutants indoors. AER differences among homes may result from a number of fact...

  1. Air Change Rates and Interzonal Flows in Residences, and the Need for Multi-Zone Models for Exposure and Health Analysis

    EPA Science Inventory

    Air change rates (ACRs) and interzonal flows are key determinants of indoor air quality (IAQ) and building energy use. This paper characterizes ACRs and interzonal flows in 126 houses, and evaluates effects of these parameters on IAQ. ACRs measured using weeklong tracer measureme...

  2. Relationships between Individual Differences and Accuracy in Rating Air Force Jet Engine Mechanic Performance

    DTIC Science & Technology

    1989-08-01

    may be enhanced to some extent (Thornton & Zorich , 1980). However, training costs may still be reduced by selecting for training those candidates with...ratee behaviors correctly noted by the rater (Thornton & Zorich , 1980). Several studies have investigated evaluation accuracy. For example, Borman (1977...correlations: Uses in assessing rater reliability. Psychological Bulletin, 86, 420-428. Thornton, G., & Zorich , S. (1980). Training to improve

  3. Monitoring the impact of the indoor air quality on silver cultural heritage objects using passive and continuous corrosion rate assessments

    NASA Astrophysics Data System (ADS)

    `t Hart, Lucy; Storme, Patrick; Anaf, Willemien; Nuyts, Gert; Vanmeert, Frederik; Dorriné, Walter; Janssens, Koen; de Wael, Karolien; Schalm, Olivier

    2016-10-01

    There is a long tradition in evaluating industrial atmospheres by measuring the corrosion rate of exposed metal coupons. The heritage community also uses this method, but the interpretation of the corrosion rate often lacks clarity due to the low corrosivity in indoor museum environments. This investigation explores the possibilities and drawbacks of different silver corrosion rate assessments. The corrosion rate is determined by three approaches: (1) chemical characterization of metal coupons using analytical techniques such as electrochemical measurements, SEM-EDX, XRD, and µ-Raman spectroscopy, (2) continuous corrosion monitoring methods based on electrical resistivity loss of a corroding nm-sized metal wire and weight gain of a corroding silver coated quartz crystal, and (3) characterization of the visual degradation of the metal coupons. This study confirms that subtle differences in corrosivity between locations inside a museum can be determined on condition that the same corrosion rate assessment is used. However, the impact of the coupon orientation with respect to the prevailing direction of air circulation can be substantially larger than the impact of the coupon location.

  4. A Feasibility Study. Ductless Hydronic Distribution Systems with Fan Coil Delivery

    SciTech Connect

    Springer, D.; Dakin, B.; Backman, C.

    2012-07-01

    The primary objectives of this study are to estimate potential energy savings relative to conventional ducted air distribution, and to identify equipment requirements, costs, and barriers with a focus on ductless hydronic delivery systems that utilize water-to-air terminal units in each zone. Results indicate that annual heating and cooling energy use can be reduced by up to 27% assuming replacement of the conventional 13 SEER heat pump and coil with a similarly rated air-to-water heat pump.

  5. SENSOR FOR INDIVIDUAL BURNER CONTROL OF FIRING RATE, FUEL-AIR RATIO, AND COAL FINENESS CORRELATION

    SciTech Connect

    Wayne Hill; Roger Demler; Robert G. Mudry

    2004-10-01

    Instrumentation difficulties encountered in the previous reporting period were addressed early in this reporting period, resulting in a new instrumentation configuration that appears to be free of the noise issues found previously. This permitted the collection of flow calibration data to begin. The first issues in question are the effects of the type and location of the transducer mount. Data were collected for 15 different transducer positions (upstream and downstream of an elbow in the pipe), with both a stud mount and a magnetic transducer mount, for each of seven combinations of air and coal flow. Analysis of these data shows that the effects of the transducer mount type and location on the resulting dynamics are complicated, and not easily captured in a single analysis. To maximize the practical value of the calibration data, further detailed calibration data will be collected with both the magnetic and stud mounts, but at a single mounting location just downstream of a pipe elbow. This testing will be performed in the Coal Flow Test Facility in the next reporting period. The program progress in this reporting period was sufficient to put us essentially back on schedule.

  6. Gas phase dispersion in compost as a function of different water contents and air flow rates.

    PubMed

    Sharma, Prabhakar; Poulsen, Tjalfe G

    2009-07-21

    Gas phase dispersion in a natural porous medium (yard waste compost) was investigated as a function of gas flow velocity and compost volumetric water content using oxygen and nitrogen as tracer gases. The compost was chosen because it has a very wide water content range and because it represents a wide range of porous media, including soils and biofilter media. Column breakthrough curves for oxygen and nitrogen were measured at relatively low pore gas velocities, corresponding to those observed in for instance soil vapor extraction systems or biofilters for air cleaning at biogas plants or composting facilities. Total gas mechanical dispersion-molecular diffusion coefficients were fitted from the breakthrough curves using a one-dimensional numerical solution to the advection-dispersion equation and used to determine gas dispersivities at different volumetric gas contents. The results showed that gas mechanical dispersion dominated over molecular diffusion with mechanical dispersion for all water contents and pore gas velocities investigated. Importance of mechanical dispersion increased with increasing pore gas velocity and compost water content. The results further showed that gas dispersivity was relatively constant at high values of compost gas-filled porosity but increased with decreasing gas-filled porosity at lower values of gas-filled porosity. Results finally showed that measurement uncertainty in gas dispersivity is generally highest at low values of pore gas velocity.

  7. Influence of liquid and gas flow rates on sulfuric acid mist removal from air by packed bed tower

    PubMed Central

    2012-01-01

    The possible emission of sulfuric acid mists from a laboratory scale, counter-current packed bed tower operated with a caustic scrubbing solution was studied. Acid mists were applied through a local exhaust hood. The emissions from the packed bed tower were monitored in three different categories of gas flow rate as well as three liquid flow rates, while other influencing parameters were kept almost constant. Air sampling and sulfuric acid measurement were carried out iso-kinetically using USEPA method 8. The acid mists were measured by the barium-thorin titration method. According to the results when the gas flow rate increased from 10 L/s to 30 L/s, the average removal efficiency increased significantly (p < 0.001) from 76.8 ± 1.8% to 85.7 ± 1.2%. Analysis of covariance method followed by Tukey post-hoc test of 92 tests did not show a significant change in removal efficiency between liquid flow rates of 1.5, 2.5 and 3.5 L/min (p = 0.811). On the other hand, with fixed pressure loss across the tower, by increasing the liquid/gas (L/G) mass ratio, the average removal efficiency decreased significantly (p = 0.001) from 89.9% at L/G of <2 to 83.1% at L/G of 2–3 and further to 80.2% at L/G of >3, respectively. L/G of 2–3 was recommended for designing purposes of a packed tower for sulfuric acid mists and vapors removal from contaminated air stream. PMID:23369487

  8. Influence of liquid and gas flow rates on sulfuric acid mist removal from air by packed bed tower.

    PubMed

    Jafari, Mohammad Javad; Ghasemi, Roohollah; Mehrabi, Yadollah; Yazdanbakhsh, Ahmad Reza; Hajibabaei, Majid

    2012-12-10

    The possible emission of sulfuric acid mists from a laboratory scale, counter-current packed bed tower operated with a caustic scrubbing solution was studied. Acid mists were applied through a local exhaust hood. The emissions from the packed bed tower were monitored in three different categories of gas flow rate as well as three liquid flow rates, while other influencing parameters were kept almost constant. Air sampling and sulfuric acid measurement were carried out iso-kinetically using USEPA method 8. The acid mists were measured by the barium-thorin titration method. According to the results when the gas flow rate increased from 10 L/s to 30 L/s, the average removal efficiency increased significantly (p < 0.001) from 76.8 ± 1.8% to 85.7 ± 1.2%. Analysis of covariance method followed by Tukey post-hoc test of 92 tests did not show a significant change in removal efficiency between liquid flow rates of 1.5, 2.5 and 3.5 L/min (p = 0.811). On the other hand, with fixed pressure loss across the tower, by increasing the liquid/gas (L/G) mass ratio, the average removal efficiency decreased significantly (p = 0.001) from 89.9% at L/G of <2 to 83.1% at L/G of 2-3 and further to 80.2% at L/G of >3, respectively. L/G of 2-3 was recommended for designing purposes of a packed tower for sulfuric acid mists and vapors removal from contaminated air stream.

  9. A multiscale Bayesian data integration approach for mapping air dose rates around the Fukushima Daiichi Nuclear Power Plant.

    PubMed

    Wainwright, Haruko M; Seki, Akiyuki; Chen, Jinsong; Saito, Kimiaki

    2017-02-01

    This paper presents a multiscale data integration method to estimate the spatial distribution of air dose rates in the regional scale around the Fukushima Daiichi Nuclear Power Plant. We integrate various types of datasets, such as ground-based walk and car surveys, and airborne surveys, all of which have different scales, resolutions, spatial coverage, and accuracy. This method is based on geostatistics to represent spatial heterogeneous structures, and also on Bayesian hierarchical models to integrate multiscale, multi-type datasets in a consistent manner. The Bayesian method allows us to quantify the uncertainty in the estimates, and to provide the confidence intervals that are critical for robust decision-making. Although this approach is primarily data-driven, it has great flexibility to include mechanistic models for representing radiation transport or other complex correlations. We demonstrate our approach using three types of datasets collected at the same time over Fukushima City in Japan: (1) coarse-resolution airborne surveys covering the entire area, (2) car surveys along major roads, and (3) walk surveys in multiple neighborhoods. Results show that the method can successfully integrate three types of datasets and create an integrated map (including the confidence intervals) of air dose rates over the domain in high resolution. Moreover, this study provides us with various insights into the characteristics of each dataset, as well as radiocaesium distribution. In particular, the urban areas show high heterogeneity in the contaminant distribution due to human activities as well as large discrepancy among different surveys due to such heterogeneity.

  10. Properties of the seawater-air interface. 2. Rates of surface film formation under steady state conditions

    SciTech Connect

    Dragcevic, D.; Pravdic, V.

    1981-05-01

    The laboratory techniques of dynamic surface tension and of surface electrical potential measurements were used to determine rates of formation and of reorientation of organic surface films at the seawater-air interface. Relaxation times of surface films were determined for three characteristic samples obtained by screen and bottle sampling in the coastal waters of the northern Adriatic area. These data were compared with those for model samples produced by spreading oleic acid and crude oil on or dissolving polyethyleneglycol and sodium dodecyl sulfate in artificial seawater. Relaxation times were in the range of 0.1-1 s for most of the samples. A good representative value for field samples is 0.2 s. The temperature-dependence (the energies of activation) for the surface film relaxation indicates that several processes control material transport toward the seawater-air interface. The findings are interpreted as showing that an almost ever-present organic surface film influences the mechanism and the rate of material transport across the sea-atmosphere boundary.

  11. Particulate Air Pollution and the Rate of Hospitalization for Congestive Heart Failure among Medicare Beneficiaries in Pittsburgh, Pennsylvania.

    PubMed Central

    Wellenius, Gregory A.; Bateson, Thomas F.; Mittleman, Murray A.; Schwartz., Joel

    2006-01-01

    We used a case-crossover approach to evaluate the association between ambient air pollution and the rate of hospitalization for congestive heart failure (CHF) among Medicare recipients (age ≥ 65) residing in Allegheny County (Pittsburgh area), PA, during 1987–1999. We also explored effect modification by age, gender, and specific secondary diagnoses. During follow-up, there were 55,019 admissions with a primary diagnosis of CHF. We found that particulate matter with aerodynamic diameter ≤ 10 μm (PM10), carbon monoxide (CO), nitrogen dioxide (NO2), and sulfur dioxide – but not ozone – were positively and significantly associated with the rate of admission on the same day in single-pollutant models. The strongest associations were observed with CO, NO2 and PM10. The associations with CO and NO2 were the most robust in two-pollutant models, remaining statistically significant even after adjusting for other pollutants. Patients with a recent myocardial infarction were at greater risk of particulate-related admission, but there was otherwise no significant effect modification by age, gender, or other secondary diagnoses. These results suggest that short-term elevations in air pollution from traffic-related sources may trigger acute cardiac decompensation of heart failure patients and that those with certain comorbid conditions may be more susceptible to these effects. PMID:15901623

  12. Development and Evaluation of a New Air Exchange Rate Algorithm for the Stochastic Human Exposure and Dose Simulation Model (ISES Presentation)

    EPA Science Inventory

    Previous exposure assessment panel studies have observed considerable seasonal, between-home and between-city variability in residential pollutant infiltration. This is likely a result of differences in home ventilation, or air exchange rates (AER). The Stochastic Human Exposure ...

  13. Oxidation and decomposition mechanisms of air sensitive aluminum clusters at high heating rates

    NASA Astrophysics Data System (ADS)

    DeLisio, Jeffery B.; Mayo, Dennis H.; Guerieri, Philip M.; DeCarlo, Samantha; Ives, Ross; Bowen, Kit; Eichhorn, Bryan W.; Zachariah, Michael R.

    2016-09-01

    Molecular near zero oxidation state clusters of metals are of interest as fuel additives. In this work high heating rate decomposition of the Al(I) tetrameric cluster, [AlBr(NEt3)]4 (Et = C2H5), was studied at heating rates of up to 5 × 105 K/s using temperature-jump time-of-flight mass spectrometry (T-jump TOFMS). Gas phase Al and AlHx species were rapidly released during decomposition of the cluster, at ∼220 °C. The activation energy for decomposition was determined to be ∼43 kJ/mol. Addition of an oxidizer, KIO4, increased Al, AlO, and HBr signal intensities, showing direct oxidation of the cluster with gas phase oxygen.

  14. Development of a Portable Gamma-ray Survey System for the Measurement of Air Dose Rates

    NASA Astrophysics Data System (ADS)

    Goto, Jun; Shobugawa, Yugo; Kawano, Yoh; Amaya, Yoshihiro; Izumikawa, Takuji; Katsuragi, Yoshinori; Shiiya, Tomohiro; Suzuki, Tsubasa; Takahashi, Takeshi; Takahashi, Toshihiro; Yoshida, Hidenori; Naito, Makoto

    BIo-Safety Hybrid Automatic MOnitor-Niigata (BISHAMON), a portable gamma-ray survey system, was developed to support victims of the Fukushima Daiichi nuclear disaster. BISHAMON is capable of constructing a map of the distribution of ambient dose equivalent rates using vehicle-mounted or on-foot survey methods. In this study, we give an overview of BISHAMON and its measurement results including a comparison with those of other systems such as KURAMA.

  15. Effect of ventilation systems and air filters on decay rates of particles produced by indoor sources in an occupied townhouse

    NASA Astrophysics Data System (ADS)

    Howard-Reed, Cynthia; Wallace, Lance A.; Emmerich, Steven J.

    Several studies have shown the importance of particle losses in real homes due to deposition and filtration; however, none have quantitatively shown the impact of using a central forced air fan and in-duct filter on particle loss rates. In an attempt to provide such data, we measured the deposition of particles ranging from 0.3 to 10 μm in an occupied townhouse and also in an unoccupied test house. Experiments were run with three different sources (cooking with a gas stove, citronella candle, pouring kitty litter), with the central heating and air conditioning (HAC) fan on or off, and with two different types of in-duct filters (electrostatic precipitator and ordinary furnace filter). Particle size, HAC fan operation, and the electrostatic precipitator had significant effects on particle loss rates. The standard furnace filter had no effect. Surprisingly, the type of source (combustion vs. mechanical generation) and the type of furnishings (fully furnished including carpet vs. largely unfurnished including mostly bare floor) also had no measurable effect on the deposition rates of particles of comparable size. With the HAC fan off, average deposition rates varied from 0.3 h -1 for the smallest particle range (0.3-0.5 μm) to 5.2 h -1 for particles greater than 10 μm. Operation of the central HAC fan approximately doubled these rates for particles <5 μm, and increased rates by 2 h -1 for the larger particles. An in-duct electrostatic precipitator increased the loss rates compared to the fan-off condition by factors of 5-10 for particles <2.5 μm, and by a factor of 3 for 2.5-5.0 μm particles. In practical terms, use of the central fan alone could reduce indoor particle concentrations by 25-50%, and use of an in-duct ESP could reduce particle concentrations by 55-85% compared to fan-off conditions.

  16. Use of reference chemicals to determine passive uptake rates of common indoor air VOCs by collocation deployment of active and passive samplers.

    PubMed

    Xian, Qiming; Feng, Yong-Lai; Chan, Cecilia C; Zhu, Jiping

    2011-09-01

    Passive samplers have become more popular in their application in the measurement of airborne chemicals. For volatile organic compounds, the rate of a chemical's diffusivity is a determining factor in the quantity of the chemical being collected for a given passive sampler. While uptake rate of a chemical in the passive sampler can be determined either by collocation deployment of both active and passive samplers or use of controlled facilities such as environmental chambers, a new approach without a need for accurate active flow rate in the collocation experiment was demonstrated in this study. This approach uses chemicals of known uptake rates as references to calculate the actual flow rate of the active sampling in the collocation experiment. The active sampling rate in turn can be used in the determination of the uptake rates of all other chemicals present in the passive samplers. The advantage of such approach is the elimination of the errors in actual active sampling rate associated with low flow employed in the collocation experiment. Using this approach, passive uptake rates of more than 80 volatile organic compounds commonly present in indoor air were determined. These experimentally determined uptake rates correlate well with air diffusivity of the chemicals, indicating the regression equation describing such correlation might be useful in predicting the uptake rates of other volatile organic chemicals in indoor air based on their air diffusivity.

  17. Measurement of air dose rates over a wide area around the Fukushima Dai-ichi Nuclear Power Plant through a series of car-borne surveys.

    PubMed

    Andoh, Masaki; Nakahara, Yukio; Tsuda, Shuichi; Yoshida, Tadayoshi; Matsuda, Norihiro; Takahashi, Fumiaki; Mikami, Satoshi; Kinouchi, Nobuyuki; Sato, Tetsuro; Tanigaki, Minoru; Takamiya, Koichi; Sato, Nobuhiro; Okumura, Ryo; Uchihori, Yukio; Saito, Kimiaki

    2015-01-01

    A series of car-borne surveys using the Kyoto University RAdiation MApping (KURAMA) and KURAMA-II survey systems has been conducted over a wide area in eastern Japan since June 2011 to evaluate the distribution of air dose rates around the Fukushima Dai-ichi Nuclear Power Plant and to evaluate the time-dependent trend of decrease in air dose rates. An automated data processing system for the KURAMA-II system was established, which enabled rapid analysis of large amounts of data obtained using about 100 KURAMA-II units. The initial data used for evaluating the migration status of radioactive cesium were obtained in the first survey, followed by other car-borne surveys conducted over more extensive and wider measurement ranges. By comparing the measured air dose rates obtained in each survey (until December 2012), the decreasing trend of air dose rates measured through car-borne surveys was found to be more pronounced than those expected on the basis of the physical decay of radioactive cesium and of the air dose rates measured using NaI (Tl) survey meters in the areas surrounding the roadways. In addition, it was found that the extent of decrease in air dose rates depended on land use, wherein it decreased faster for land used as building sites than for forested areas.

  18. A Novel Method for Quantifying the Inhaled Dose of Air Pollutants Based on Heart Rate, Breathing Rate and Forced Vital Capacity

    PubMed Central

    Greenwald, Roby; Hayat, Matthew J.; Barton, Jerusha; Lopukhin, Anastasia

    2016-01-01

    To better understand the interaction of physical activity and air pollution exposure, it is important to quantify the change in ventilation rate incurred by activity. In this paper, we describe a method for estimating ventilation using easily-measured variables such as heart rate (HR), breathing rate (fB), and forced vital capacity (FVC). We recruited healthy adolescents to use a treadmill while we continuously measured HR, fB, and the tidal volume (VT) of each breath. Participants began at rest then walked and ran at increasing speed until HR was 160–180 beats per minute followed by a cool down period. The novel feature of this method is that minute ventilation (V˙E) was normalized by FVC. We used general linear mixed models with a random effect for subject and identified nine potential predictor variables that influence either V˙E or FVC. We assessed predictive performance with a five-fold cross-validation procedure. We used a brute force selection process to identify the best performing models based on cross-validation percent error, the Akaike Information Criterion and the p-value of parameter estimates. We found a two-predictor model including HR and fB to have the best predictive performance (V˙E/FVC = -4.247+0.0595HR+0.226fB, mean percent error = 8.1±29%); however, given the ubiquity of HR measurements, a one-predictor model including HR may also be useful (V˙E/FVC = -3.859+0.101HR, mean percent error = 11.3±36%). PMID:26809066

  19. SCC Propagation Rate of Type 304, 304L Steels Under Oceanic Air Environment

    SciTech Connect

    Akio Kosaki

    2006-07-01

    Corrosion integrity of canister in the concrete cask for spent fuel storage is very important because the canister serves to maintain the sealability over the storage period of 40 to 60 years. Natural exposure and accelerated corrosion tests of conventional stainless steels for canister, that are Type 304, 304L, and 316(LN), for concrete cask's canister have been conducted by using many three Point Bending (3PB) test specimens and compared. The SCC propagation rates in Type 304 and 304L at the natural condition were about 1.2 E-12 to 1.8 E-11 m/s at the K (Stress Intensity Factor) range of 0.6 to 9.0 MPa/m, and that of the accelerate test (60 degrees C, 95%RHS., filled with NaCl mist.) were about 1.0 E-10 to 3.5 E-9 m/s at the K range of 0.3 to 32 MPa/m. The SCC propagation rates under both natural and accelerated conditions were independent with K. Both da/dt values of the direct exposure test and of the under glass exposure test were in the same scattering band. (author)

  20. Air pollution and mortality rates: a note on Lave and Seskin's pooling of cross-section and time-series data

    SciTech Connect

    Christainsen, G.B.; Degen, C.G.

    1980-06-01

    Air Pollution and Human Health (Johns Hopkins University Press, Baltimore, 1977) by Lester Lave and Eugene Seskin reports the results of regressions which suggest a strong association between air pollution and mortality rates. This note questions assumptions made by Lave and Seskin which underlie their estimation of a single-equation model using pooled cross-section and time-series data. If, in fact, these assumptions cannot be made, the association between air pollution and mortality rates appears considerably weakened, but it still appears to be significant.

  1. Gas exchange rates across the sediment-water and air-water interfaces in south San Francisco Bay

    USGS Publications Warehouse

    Hartman, Blayne; Hammond, Douglas E.

    1984-01-01

    Radon 222 concentrations in the water and sedimentary columns and radon exchange rates across the sediment-water and air-water interfaces have been measured in a section of south San Francisco Bay. Two independent methods have been used to determine sediment-water exchange rates, and the annual averages of these methods agree within the uncertainty of the determinations, about 20%. The annual average of benthic fluxes from shoal areas is nearly a factor of 2 greater than fluxes from the channel areas. Fluxes from the shoal and channel areas exceed those expected from simple molecular diffusion by factors of 4 and 2, respectively, apparently due to macrofaunal irrigation. Values of the gas transfer coefficient for radon exchange across the air-water interface were determined by constructing a radon mass balance for the water column and by direct measurement using floating chambers. The chamber method appears to yield results which are too high. Transfer coefficients computed using the mass balance method range from 0.4 m/day to 1.8 m/day, with a 6-year average of 1.0 m/day. Gas exchange is linearly dependent upon wind speed over a wind speed range of 3.2–6.4 m/s, but shows no dependence upon current velocity. Gas transfer coefficients predicted from an empirical relationship between gas exchange rates and wind speed observed in lakes and the oceans are within 30% of the coefficients determined from the radon mass balance and are considerably more accurate than coefficients predicted from theoretical gas exchange models.

  2. Association between indoor air pollutant exposure and blood pressure and heart rate in subjects according to body mass index.

    PubMed

    Jung, Chien-Cheng; Su, Huey-Jen; Liang, Hsiu-Hao

    2016-01-01

    This study investigates the effects of high body mass index (BMI) of subjects on individual who exhibited high cardiovascular disease indexes with blood pressure (BP) and heart rate (HR) when exposed to high levels of indoor air pollutants. We collected 115 office workers, and measured their systolic blood pressure (SBP), diastolic blood pressure (DBP) and HR at the end of the workday. The subjects were divided into three groups according to BMI: 18-24 (normal weight), 24-27 (overweight) and >27 (obese). This study also measured the levels of carbon dioxide (CO2), total volatile organic compounds (TVOC), particulate matter with an aerodynamic diameter less than 2.5μm (PM2.5), as well as the bacteria and fungi in the subjects' work-places. The pollutant effects were divided by median. Two-way analysis of variance (ANOVA) was used to analyze the health effects of indoor air pollution exposure according to BMI. Our study showed that higher levels of SBP, DBP and HR occurred in subjects who were overweight or obese as compared to those with normal weight. Moreover, there was higher level of SBP in subjects who were overweight or obese when they were exposed to higher levels of TVOC and fungi (p<0.05). We also found higher value for DBP and HR with increasing BMI to be associated with exposure to higher TVOC levels. This study suggests that individuals with higher BMI have higher cardiovascular disease risk when they are exposed to poor indoor air quality (IAQ), and specifically in terms of TVOC.

  3. The rate of second electron transfer to QB(-) in bacterial reaction center of impaired proton delivery shows hydrogen-isotope effect.

    PubMed

    Maróti, Ágnes; Wraight, Colin A; Maróti, Péter

    2015-02-01

    The 2nd electron transfer in reaction center of photosynthetic bacterium Rhodobacter sphaeroides is a two step process in which protonation of QB(-) precedes interquinone electron transfer. The thermal activation and pH dependence of the overall rate constants of different RC variants were measured and compared in solvents of water (H2O) and heavy water (D2O). The electron transfer variants where the electron transfer is rate limiting (wild type and M17DN, L210DN and H173EQ mutants) do not show solvent isotope effect and the significant decrease of the rate constant of the second electron transfer in these mutants is due to lowering the operational pKa of QB(-)/QBH: 4.5 (native), 3.9 (L210DN), 3.7 (M17DN) and 3.1 (H173EQ) at pH7. On the other hand, the proton transfer variants where the proton transfer is rate limiting demonstrate solvent isotope effect of pH-independent moderate magnitude (2.11±0.26 (WT+Ni(2+)), 2.16±0.35 (WT+Cd(2+)) and 2.34±0.44 (L210DN/M17DN)) or pH-dependent large magnitude (5.7 at pH4 (L213DN)). Upon deuteration, the free energy and the enthalpy of activation increase in all proton transfer variants by about 1 kcal/mol and the entropy of activation becomes negligible in L210DN/M17DN mutant. The results are interpreted as manifestation of equilibrium and kinetic solvent isotope effects and the structural, energetic and kinetic possibility of alternate proton delivery pathways are discussed.

  4. Continuous measurements of air change rates in an occupied house for 1 year: the effect of temperature, wind, fans, and windows.

    PubMed

    Wallace, L A; Emmerich, S J; Howard-Reed, C

    2002-07-01

    A year-long investigation of air change rates in an occupied house was undertaken to establish the effects of temperature, wind velocity, use of exhaust fans, and window-opening behavior. Air change rates were calculated by periodically injecting a tracer gas (SF(6)) into the return air duct and measuring the concentration in 10 indoor locations sequentially every minute by a gas chromatograph equipped with an electron capture detector. Temperatures were also measured outdoors and in the 10 indoor locations. Relative humidity (RH) was measured outdoors and in five indoor locations every 5 min. Wind speed and direction in the horizontal plane were measured using a portable meteorological station mounted on the rooftop. Use of the thermostat-controlled attic fan was recorded automatically. Indoor temperatures increased from 21 degrees C in winter to 27 degrees C in summer. Indoor RH increased from 20% to 70% in the same time period. Windows were open only a few percent of the time in winter but more than half the time in summer. About 4600 hour-long average air change rates were calculated from the measured tracer gas decay rates. The mean (SD) rate was 0.65 (0.56) h(-1). Tracer gas decay rates in different rooms were very similar, ranging only from 0.62 to 0.67 h(-1), suggesting that conditions were well mixed throughout the year. The strongest influence on air change rates was opening windows, which could increase the rate to as much as 2 h(-1) for extended periods, and up to 3 h(-1) for short periods of a few hours. The use of the attic fan also increased air change rates by amounts up to 1 h(-1). Use of the furnace fan had no effect on air change rates. Although a clear effect of indoor-outdoor temperature difference could be discerned, its magnitude was relatively small, with a very large temperature difference of 30 degrees C (54 degrees F) accounting for an increase in the air change rate of about 0.6 h(-1). Wind speed and direction were found to have very

  5. Combustion rate limits of hydrogen plus hydrocarbon fuel: Air diffusion flames from an opposed jet burner technique

    NASA Technical Reports Server (NTRS)

    Pellett, Gerald L.; Guerra, Rosemary; Wilson, Lloyd G.; Reeves, Ronald N.; Northam, G. Burton

    1987-01-01

    Combustion of H2/hydrocarbon (HC) fuel mixtures may be considered in certain volume-limited supersonic airbreathing propulsion applications. Effects of HC addition to H2 were evaluated, using a recent argon-bathed, coaxial, tubular opposed jet burner (OJB) technique to measure the extinction limits of counterflow diffusion flames. The OJB flames were formed by a laminar jet of (N2 and/or HC)-diluted H2 mixture opposed by a similar jet of air at ambient conditions. The OJB data, derived from respective binary mixtures of H2 and methane, ethylene, or propane HCs, were used to characterize BLOWOFF and RESTORE. BLOWOFF is a sudden breaking of the dish-shaped OJB flame to a stable torus or ring shape, and RESTORE marks sudden restoration of the central flame by radial inward flame propagation. BLOWOFF is a measure of kinetically-limited flame reactivity/speed under highly stretched, but relatively ideal impingement flow conditions. RESTORE measures inward radial flame propagation rate, which is sensitive to ignition processes in the cool central core. It is concluded that relatively small molar amounts of added HC greatly reduce the reactivity characteristics of counterflow hydrogen-air diffusion flames, for ambient initial conditions.

  6. SENSOR FOR INDIVIDUAL BURNER CONTROL OF FIRING RATE, FUEL-AIR RATIO, AND COAL FINENESS CORRELATION

    SciTech Connect

    Wayne Hill; Roger Demler; Robert G. Mudry

    2005-04-01

    A no-cost time extension was requested, to permit additional laboratory testing prior to undertaking field data collection. This was received in this reporting period. To minimize program cost, this additional testing is planned to be performed in concert with EPRI-funded testing at the Coal Flow Test Facility. Since the EPRI schedule was undecided, a hiatus occurred in the test effort. Instead, a significant effort was exerted to analyze the available laboratory test data to see whether the source and nature of noise behaviors could be identified, or whether the key flow information could be extracted even in the presence of the noise. One analysis approach involved filtering the data numerically to reject dynamics outside of various frequency bands. By varying the center frequency and width of the band, the effect of signal frequency on flow dynamics could be examined. Essentially equivalent results were obtained for all frequency bands that excluded a neighborhood of the transducer resonance, indicating that there is little advantage to be gained by limiting the experimental frequency window. Another approach examined the variation of the dynamics over a series of 1-second windows of data, producing an improvement in the prediction of coal flow rate. Yet another approach compared the dynamics of a series of 1-second windows to those of a series of 5-second windows, producing still better results. These results will be developed further in the next reporting period, which should also include further laboratory testing at the Coal Flow Test Facility.

  7. SENSOR FOR INDIVIDUAL BURNER CONTROL OF FIRING RATE, FUEL-AIR RATIO, AND COAL FINENESS CORRELATION

    SciTech Connect

    Wayne Hill; Roger Demler; Robert G. Mudry

    2005-01-01

    Additional calibration data were collected in the Coal Flow Test Facility early in this reporting period. These data comprised a total of 181 tests for stud and magnetic accelerometer mounts, with two mounting locations relative to two different pipe elbows, and including some tests with out-of-plane elbows upstream of the test section to produce coal ''roping''. The results found in analyzing these new data were somewhat disappointing: correlations for coal flow rate for a given mount type and mounting location were less accurate than desired, and degraded badly when data from other locations were included in the same analysis. Reviewing all of the data files (from both the earlier testing and recent calibration testing) disclosed a significant fraction of cases with several forms of noise. Eliminating these cases improved the correlations somewhat, but the number of cases that remained did not permit general conclusions to be drawn. It was finally learned that yet another type of noise is present in some data files, producing a strong effect on the correlation accuracy. The cases not subject to this noise correlated very well. It would be desirable to collect additional data in the Coal Flow Test Facility prior to moving on to field data collection, a change in program direction that would require a no-cost time extension.

  8. Chemical characterization of indoor air of homes from communes in Xuan Wei, China, with high lung cancer mortality rate

    NASA Astrophysics Data System (ADS)

    Chuang, J. C.; Cao, S. R.; Xian, Y. L.; Harris, D. B.; Mumford, J. L.

    In a rural county, Xuan Wei, China, the lung cancer mortality rate is among China's highest, especially in women. This mortality rate is more associated with indoor air burning of smoky coal, as opposed to smokeless coal or wood, for cooking and heating under unvented conditions. Homes using different fuels from communes with high and low lung cancer mortality rates were sampled for particulate matter (< 10 μm) and semivolatile organics. The fine particles obtained from homes using smoky coal contained highest concentrations of organic matter (> 70%), including PAH, followed by homes using wood and smokeless coal. The major components present in the smoky coal filter samples were PAH and alkylated PAH. The smokeless coal filter samples exhibited profiles which were similar to the smoky coal samples except that some sulfur compounds were found. The estimated concentration levels of PAH in the smokeless coal samples were about one to two orders of magnitude lower than those of the smoky coal samples. In addition to PAH, aliphatic compounds and fatty acids were the major components found in the wood samples. Selected sample extracts from homes using smoky coal were fractionated into four fractions, and the results showed that the PAH and polar fractions have high mutagenic activity. Chemical characterization of the PAH fraction indicated that concentrations of some alkylated PAH were higher than those of their parent compounds. Chemical characterization of the polar fractions showed that nitrogen heterocyclic compounds are present.

  9. Heart rate and heart rate variability assessment identifies individual differences in fear response magnitudes to earthquake, free fall, and air puff in mice.

    PubMed

    Liu, Jun; Wei, Wei; Kuang, Hui; Tsien, Joe Z; Zhao, Fang

    2014-01-01

    Fear behaviors and fear memories in rodents have been traditionally assessed by the amount of freezing upon the presentation of conditioned cues or unconditioned stimuli. However, many experiences, such as encountering earthquakes or accidental fall from tree branches, may produce long-lasting fear memories but are behaviorally difficult to measure using freezing parameters. Here, we have examined changes in heartbeat interval dynamics as physiological readout for assessing fearful reactions as mice were subjected to sudden air puff, free-fall drop inside a small elevator, and a laboratory-version earthquake. We showed that these fearful events rapidly increased heart rate (HR) with simultaneous reduction of heart rate variability (HRV). Cardiac changes can be further analyzed in details by measuring three distinct phases: namely, the rapid rising phase in HR, the maximum plateau phase during which HRV is greatly decreased, and the recovery phase during which HR gradually recovers to baseline values. We showed that durations of the maximum plateau phase and HR recovery speed were quite sensitive to habituation over repeated trials. Moreover, we have developed the fear resistance index based on specific cardiac response features. We demonstrated that the fear resistance index remained largely consistent across distinct fearful events in a given animal, thereby enabling us to compare and rank individual mouse's fear responsiveness among the group. Therefore, the fear resistance index described here can represent a useful parameter for measuring personality traits or individual differences in stress-susceptibility in both wild-type mice and post-traumatic stress disorder (PTSD) models.

  10. Biodrying of sewage sludge: kinetics of volatile solids degradation under different initial moisture contents and air-flow rates.

    PubMed

    Villegas, Manuel; Huiliñir, Cesar

    2014-12-01

    This study focuses on the kinetics of the biodegradation of volatile solids (VS) of sewage sludge for biodrying under different initial moisture contents (Mc) and air-flow rates (AFR). For the study, a 3(2) factorial design, whose factors were AFR (1, 2 or 3L/minkgTS) and initial Mc (59%, 68% and 78% w.b.), was used. Using seven kinetic models and a nonlinear regression method, kinetic parameters were estimated and the models were analyzed with two statistical indicators. Initial Mc of around 68% increases the temperature matrix and VS consumption, with higher moisture removal at lower initial Mc values. Lower AFRs gave higher matrix temperatures and VS consumption, while higher AFRs increased water removal. The kinetic models proposed successfully simulate VS biodegradation, with root mean square error (RMSE) between 0.007929 and 0.02744, and they can be used as a tool for satisfactory prediction of VS in biodrying.

  11. Quantifying Molecular Hydrogen Emissions and an Industrial Leakage Rate for the South Coast Air Basin of California

    NASA Astrophysics Data System (ADS)

    Irish, M. C.; Schroeder, J.; Beyersdorf, A. J.; Blake, D. R.

    2015-12-01

    The poorly understood atmospheric budget and distribution of molecular hydrogen (H2) have invited further research since the discovery that emissions from a hydrogen-based economy could have negative impacts on the global climate system and stratospheric ozone. The burgeoning fuel cell electric vehicle industry in the South Coast Air Basin of California (SoCAB) presents an opportunity to observe and constrain urban anthropogenic H2 emissions. This work presents the first H2 emissions estimate for the SoCAB and calculates an upper limit for the current rate of leakage from production and distribution infrastructure within the region. A top-down method utilized whole air samples collected during the Student Airborne Research Program (SARP) onboard the NASA DC-8 research aircraft from 23-25 June 2015 to estimate H2 emissions from combustion and non-combustion sources. H2:carbon monoxide (CO) and H2:carbon dioxide ratios from airborne observations were compared with experimentally established ratios from pure combustion source ratios and scaled with the well-constrained CO emissions inventory to yield H2 emissions of 24.9 ± 3.6 Gg a-1 (1σ) from combustion engines and 8.2 ± 4.7 Gg a-1 from non-combustion sources. Total daily production of H2 in the SoCAB was compared with the top-down results to estimate an upper limit leakage rate (5%) where all emissions not accounted for by incomplete combustion in engines were assumed to be emitted from H2 infrastructure. For bottom-up validation, the NOAA Hybrid Single Particle Lagrangian Integrated Trajectory dispersion model was run iteratively with all known stationary sources in attempt to constrain emissions. While this investigation determined that H2 emissions from non-combustion sources in the SoCAB are likely significant, more in-depth analysis is required to better predict the atmospheric implications of a hydrogen economy.

  12. [METHODOLOGY FOR THE ASSESSMENT OF THE IMPACT OF THE ATMOSPHERIC AIR POLLUTION ON THE FORMATION OF THE LEVELS OF OVERALL MORBIDITY RATE OF BRONCHIAL ASTHMA].

    PubMed

    Veremchuk, L V; Cherpack, N A; Gvozdenko, T A; Volkova, M V

    2015-01-01

    In large cities with strong air pollution the formation of the levels of morbidity rate of bronchial asthma has a complex causation that requires the search for informative methods for identification of causes and consequences of this dependence. Method for the assessment of the dependence of overall levels of morbidity rate of bronchial asthma on the degree of air pollution allows you to select a "useful information" of the direct impact of air pollution on a background of random processes and latent relationship between human and environment. The use of the method of the information entropy analysis allowed us to estimate the total and the individual contribution of the separate components of air pollution on the formation of levels of total morbidity rate of bronchial asthma in the population of the city of Vladivostok. Levels of total incidence of this pathology were established to differ in various age groups. The adult population is more adapted to air pollution, but retains a high sensitivity to the impact of nitrogen dioxide. Levels of overall l morbidity rate of bronchial asthma in children and adolescents depend on the total air pollution with some dominance of the influence of suspended matter and carbon monoxide.

  13. Relationship between heart rate variability, blood pressure and arterial wall properties during air and oxygen breathing in healthy subjects.

    PubMed

    Graff, Beata; Szyndler, Anna; Czechowicz, Krzysztof; Kucharska, Wiesława; Graff, Grzegorz; Boutouyrie, Pierre; Laurent, Stephane; Narkiewicz, Krzysztof

    2013-11-01

    Previous studies reported that normobaric hyperoxia influences heart rate, arterial pressure, cardiac output and systemic vascular resistance, but the mechanisms underlying these changes are still not fully understood. Several factors are considered including degeneration of endothelium-derived nitric oxide by reactive oxygen species, the impact of oxygen-free radicals on tissues and alterations of autonomic nervous system function. Recently, new devices for the detailed non-invasive assessment of large and small arteries have been developed. Therefore, the aim of our study was to assess heart rate variability (HRV) as a potential indicator of autonomic balance and its relation to blood pressure and vascular properties during medical air (MAB) and 100% oxygen breathing (OXB) in healthy volunteers. In 12 healthy subjects we assessed heart rate and blood pressure variability, baroreflex sensitivity, respiratory frequency, common carotid artery diameter and its wall distensibility, as well as changes in the digital artery pulse waveform, stroke index and systemic vascular resistance during MAB and OXB. Mean and systolic blood pressure have increased significantly while digital pulse amplitude and carotid artery diameter were significantly lower during hyperoxia. Heart rate variability measures did not differ during MAB and OXB. However, the correlations between spectral HRV components and those hemodynamic parameters which have changed due to hyperoxia varied substantially during MAB (correlated significantly) and OXB (no significant correlations were noted). Our findings suggest that autonomic nervous system might not be the main mediator of the cardiovascular changes during 100% oxygen breathing in healthy subjects. It seems that the direct vascular responses are initial consequences of hyperoxia and other cardiovascular parameter alterations are secondary to them.

  14. Prevalence rates of respiratory symptoms in Italian general population samples exposed to different levels of air pollution

    SciTech Connect

    Viegi, G. Univ. of Arizona, Tucson ); Paoletti, P.; Carrozzi, L.; Vellutini, M.; Diviggiano, E.; Pistelli, G.; Giutini, G. ); Di Pede, C. Occupational Medicine Service, Toscana ); Lebowitz, M.D. )

    1991-08-01

    The authors surveyed two general population samples aged 8 to 64 living in the unpolluted, rural area of the Po Delta (northern Italy) and in the urban area of Pisa (central Italy). Each subject filled out a standardized interviewer-administered questionnaire. The Pisa sample was divided into three groups according to their residence in the urban-suburban areas and to outdoor air pollution exposure (automobile exhaust only or industrial fumes as well). Significantly higher prevalence rates of all the respiratory symptoms and diseases were found in Pisa compared with the Po Delta. Current smoking was more frequent in the rural area, but the urban smokers had a higher lifetime cigarette consumption. Childhood respiratory trouble and recurrent respiratory illnesses were evenly distributed. Exposure to parental smoking in childhood and lower educational level were more frequent in Po Delta, whereas familial history of respiratory/allergic disorders and work and indoor exposures were more often reported in the city. Multiple logistic regression models estimating independently the role of the various risk factors showed significant odds ratios associated with residence in Pisa for all the symptoms but chronic phlegm. The conclusion, these preliminary analyses indicate an urban factor related to the rates of respiratory symptoms and diseases in Italy in the 1980s.

  15. Oxidation rate of nuclear-grade graphite NBG-18 in the kinetic regime for VHTR air ingress accident scenarios

    NASA Astrophysics Data System (ADS)

    Lee, Jo Jo; Ghosh, Tushar K.; Loyalka, Sudarshan K.

    2013-07-01

    One of the most severe accident scenarios anticipated for VHTRs is an air ingress accident caused by a pipe break. Graphite oxidation could be severe under these conditions. In this work, the oxidation rate of NBG-18 nuclear-grade graphite was studied thermogravimetrically for different oxygen concentrations and with temperatures from 873 to 1873 K. A semi-empirical Arrhenius rate equation was developed for the temperature range of 873-1023 K. The activation energy of NBG-18 was 187 kJ/mol and the order of reaction was 1.25. The penetration depth of oxidant was about 3-4 mm for NBG-18 oxidized at 973 K. Increased porosity and changes in external geometry became more prominent at higher temperatures from about 1173 to 1873 K. The surface of oxidized NBG-18 was characterized by SEM, EDS, FTIR and XPS. Diffusion of oxygen to the graphite surface and walls of open volume pores. Adsorption of oxygen atoms on the graphite surface free active sites and complexes inducing the simultaneous forming of Csbnd O and Csbnd H bonds and breaking of Csbnd C bonds (dissociative chemisorption). Chemical reactions occur at the surface. Desorption of gaseous products, CO and CO2, from the graphite surface and transport to the bulk gas mixture.

  16. Selective attention and the auditory vertex potential. I - Effects of stimulus delivery rate. II - Effects of signal intensity and masking noise

    NASA Technical Reports Server (NTRS)

    Schwent, V. L.; Hillyard, S. A.; Galambos, R.

    1976-01-01

    The effects of varying the rate of delivery of dichotic tone pip stimuli on selective attention measured by evoked-potential amplitudes and signal detectability scores were studied. The subjects attended to one channel (ear) of tones, ignored the other, and pressed a button whenever occasional targets - tones of a slightly higher pitch were detected in the attended ear. Under separate conditions, randomized interstimulus intervals were short, medium, and long. Another study compared the effects of attention on the N1 component of the auditory evoked potential for tone pips presented alone and when white noise was added to make the tones barely above detectability threshold in a three-channel listening task. Major conclusions are that (1) N1 is enlarged to stimuli in an attended channel only in the short interstimulus interval condition (averaging 350 msec), (2) N1 and P3 are related to different modes of selective attention, and (3) attention selectivity in multichannel listening task is greater when tones are faint and/or difficult to detect.

  17. A review of reaction rates and thermodynamic and transport properties for the 11-species air model for chemical and thermal nonequilibrium calculations to 30000 K

    NASA Technical Reports Server (NTRS)

    Gupta, Roop N.; Yos, Jerrold M.; Thompson, Richard A.

    1989-01-01

    Reaction rate coefficients and thermodynamic and transport properties are provided for the 11-species air model which can be used for analyzing flows in chemical and thermal nonequilibrium. Such flows will likely occur around currently planned and future hypersonic vehicles. Guidelines for determining the state of the surrounding environment are provided. Approximate and more exact formulas are provided for computing the properties of partially ionized air mixtures in such environments.

  18. The characteristics of coarse particulate matter air pollution associated with alterations in blood pressure and heart rate during controlled exposures

    PubMed Central

    Morishita, Masako; Bard, Robert L.; Wang, Lu; Das, Ritabrata; Dvonch, J. Timothy; Spino, Catherine; Mukherjee, Bhramar; Sun, Qinghua; Harkema, Jack R.; Rajagopalan, Sanjay; Brook, Robert D.

    2015-01-01

    Although fine particulate matter (PM) air pollution <2.5 μm in aerodynamic diameter (PM2.5) is a leading cause of global morbidity and mortality, the potential health effects of coarse PM (2.5–10 μm in aerodynamic diameter; PM10–2.5) remain less clearly understood. We aimed to elucidate the components within coarse PM most likely responsible for mediating these hemodynamic alterations. Thirty-two healthy adults (25.9 ± 6.6 years) were exposed to concentrated ambient coarse PM (CAP) (76.2 ± 51.5 μg/m3) and filtered air (FA) for 2 h in a rural location in a randomized double-blind crossover study. The particle constituents (24 individual elements, organic and elemental carbon) were analyzed from filter samples and associated with the blood pressure (BP) and heart rate (HR) changes occurring throughout CAP and FA exposures in mixed model analyses. Total coarse PM mass along with most of the measured elements were positively associated with similar degrees of elevations in both systolic BP and HR. Conversely, total PM mass was unrelated, whereas only two elements (Cu and Mo) were positively associated with and Zn was inversely related to diastolic BP changes during exposures. Inhalation of coarse PM from a rural location rapidly elevates systolic BP and HR in a concentration-responsive manner, whereas the particulate composition does not appear to be an important determinant of these responses. Conversely, exposure to certain PM elements may be necessary to trigger a concomitant increase in diastolic BP. These findings suggest that particulate mass may be an adequate metric of exposure to predict some, but not all, hemodynamic alterations induced by coarse PM mass. PMID:25227729

  19. ANEMOS: A computer code to estimate air concentrations and ground deposition rates for atmospheric nuclides emitted from multiple operating sources

    SciTech Connect

    Miller, C.W.; Sjoreen, A.L.; Begovich, C.L.; Hermann, O.W.

    1986-11-01

    This code estimates concentrations in air and ground deposition rates for Atmospheric Nuclides Emitted from Multiple Operating Sources. ANEMOS is one component of an integrated Computerized Radiological Risk Investigation System (CRRIS) developed for the US Environmental Protection Agency (EPA) for use in performing radiological assessments and in developing radiation standards. The concentrations and deposition rates calculated by ANEMOS are used in subsequent portions of the CRRIS for estimating doses and risks to man. The calculations made in ANEMOS are based on the use of a straight-line Gaussian plume atmospheric dispersion model with both dry and wet deposition parameter options. The code will accommodate a ground-level or elevated point and area source or windblown source. Adjustments may be made during the calculations for surface roughness, building wake effects, terrain height, wind speed at the height of release, the variation in plume rise as a function of downwind distance, and the in-growth and decay of daughter products in the plume as it travels downwind. ANEMOS can also accommodate multiple particle sizes and clearance classes, and it may be used to calculate the dose from a finite plume of gamma-ray-emitting radionuclides passing overhead. The output of this code is presented for 16 sectors of a circular grid. ANEMOS can calculate both the sector-average concentrations and deposition rates at a given set of downwind distances in each sector and the average of these quantities over an area within each sector bounded by two successive downwind distances. ANEMOS is designed to be used primarily for continuous, long-term radionuclide releases. This report describes the models used in the code, their computer implementation, the uncertainty associated with their use, and the use of ANEMOS in conjunction with other codes in the CRRIS. A listing of the code is included in Appendix C.

  20. Modeling Spatial and Temporal Variability of Residential Air Exchange Rates for the Near-Road Exposures and Effects of Urban Air Pollutants Study (NEXUS)

    EPA Science Inventory

    Air pollution health studies often use outdoor concentrations as exposure surrogates. Failure to account for variability of residential infiltration of outdoor pollutants can induce exposure errors and lead to bias and incorrect confidence intervals in health effect estimates. Th...

  1. Remifentanil patient-controlled analgesia for labor – monitoring of newborn heart rate, blood pressure and oxygen saturation during the first 24 hours after delivery

    PubMed Central

    Konefał, Halina; Jaskot, Brygida; Pastuszka, Joanna

    2012-01-01

    Introduction There is no available information about the effects of remifentanil labor analgesia on newborns’ vital signs in the first hours after delivery. The aim of the study was to assess changes in the heart rate, blood pressure and oxygen saturation during the first 24 h of neonatal life after using remifentanil patient-controlled analgesia (PCA) for labor analgesia. Material and methods Forty-four full-term neonates, 23 from intravenous PCA remifentanil labor anesthesia 0.2 µg/kg, repeated not more frequently than every 2 min, and 21 born to mothers without any pharmacological forms of analgesia, were studied. Heart rate, oxygen saturation, and systolic (SBP) and diastolic blood pressure (DBP) were monitored using a Nellcor Oxi Max monitor N5500 (Tyco Healthcare), and recorded at 1 h, 6 h, 12 h and 24 h. Results No significant differences in heart rate (p = 0.54; p = 0.26; p = 0.60; p = 0.83), oxygen saturation (p = 0.21; p = 0.27; p = 0.61; p = 0.9) and DBP (p = 0.98; p = 0.31; p = 0.83; p = 0.58) between the groups at 1 h, 6 h, 12 h and 24 h. Newborns from the remifentanil group had lower SBP at 1 h of life (59 mm Hg vs. 68.5 mm Hg) but the difference was just on the borderline of statistical significance (p > 0.06). There were no significant differences in SBP between the groups at 6 h (p = 0.65), 12 h (p = 0.11), and 24 h (p = 0.89) of life. Conclusions Remifentanil PCA analgesia during labor does not significantly modify the oxygen saturation, heart rate and blood pressure in infants during the first day of their life. Therefore, further studies are needed to explain the observed trend for arterial hypotension in the first hour of life in infants born to mothers treated with remifentanil. PMID:24049531

  2. Natural variation of ambient dose rate in the air of Izu-Oshima Island after the Fukushima Daiichi Nuclear Power Plant accident.

    PubMed

    Maedera, Fumihiko; Inoue, Kazumasa; Sugino, Masato; Sano, Ryosuke; Furue, Mai; Shimizu, Hideo; Tsuruoka, Hiroshi; Le Van, Tan; Fukushi, Masahiro

    2016-03-01

    The ambient dose rate in air and radioactivity concentration in soil samples collected on Izu-Oshima Island were observed in 2012, 2013 and 2014, i.e. 1, 2 and 3 years after the severe accident at the Fukushima Daiichi Nuclear Power Plant. A car-borne survey for the ambient dose rate in air was carried out for the entire island. Soil samples were collected for the radioactivity concentration measurements from 22 points. The ambient dose rates in air were 36 nGy h(-1) in 2012, 34 nGy h(-1) in 2013 and 29 nGy h(-1) in 2014. The corresponding radioactivity concentrations in those years for (134)Cs were 53, 39 and 29 Bq kg(-1) and for (137)Cs, 87, 73 and 75 Bq kg(-1). All the values have decreased every year.

  3. Death rate in a small air-lift loop reactor of vero cells grown on solid microcarriers and in macroporous microcarriers.

    PubMed

    Martens, D E; Nollen, E A; Hardeveld, M; van der Velden-de Groot, C A; de Gooijer, C D; Beuvery, E C; Tramper, J

    1996-01-01

    The death rate of Vero cells grown on Cytodex-3 microcarriers was studied as a function of the gas flow rate in a small air-lift loop reactor. The death rate may be described by first-order death-rate kinetics. The first-order death-rate constant as calculated from the decrease in viable cells, the increase in dead cells and the increase in LDH activity is linear proportional to the gas flow rate, with a specific hypothetical killing volume in which all cells are killed of about 2·10(-3) m(3) liquid per m(3) of air bubbles. In addition, an experiment was conducted in the same air-lift reactor with Vero cells grown inside porous Asahi microcarriers. The specific hypothetical killing volume calculated from this experiment has a value of 3·10(-4) m(3) liquid per m(3) of air bubbles, which shows that the porous microcarriers were at least in part able to protect the cells against the detrimental hydrodynamic forces generated by the bubbles.

  4. Smog O3 Production Rate in California Air: Marker Compounds Allow Checks on Source Attribution to Fire and Other Sources

    NASA Astrophysics Data System (ADS)

    Chatfield, R. B.; Esswein, R. F.; Cai, C.; Kaduwela, A.; Kulkarni, S.; Blake, D. R.; Weinheimer, A. J.; Fried, A.; Huey, L. G.

    2012-12-01

    We are able to attribute sources of both radical reactivity and NO that determined the smog-chemical production rate of ozone, P(O3), for NASA's wide-ranging sampling of California air in June, 2008, part of the ARCTAS intensive. We relate formaldehyde, HCHO, and reactive nitrogen oxides, NOx, to a variety of distinct "marker" species that identify origins. We have labeled the sources and markers as (i) Fire emissions (CH3CN), (ii) Biogenic emissions (Isoprene), (iii) Urban/business emissions (CHCl3), (iv) Transport-related fuel consumption, (SO2), and (v) Refining/Port emissions ("residual" toluene). We use multiple linear regression with some appropriate restrictions. We achieve R-squared or explained variance of 88% for HCHO (VOC's) and 60% for NOx. HCHO and NOx are slowly evolving measures of potential ozone generation. The two related but radiation-influenced measures j (HCHO->H+HCO) x [HCHO] and [NO] quantitatively, but non-linearly, relate to instantaneous ozone production in California air, with R-squared of 86-93%, just as in New York City (Chatfield et al., Atmos. Environ., 2010). Maps of attribution for 650 samples from the Port of San Diego to the Northern Sierra foothills, and offshore -— all show huge variability in source attributions for VOCs and NOx. They indicate a widespread fire-emission influence on VOCs as they produce peroxy radicals, but show no positive influence on NOx, in fact consuming NOx from other sources. Comparisons with simulations help to refine our attribution classes and also to check balances of VOC emissions in available inventories. The use of the P(O3) measures is directly translatable to a method for estimate smog-ozone production rate from space, as data from another intensive, DISCOVER-AQ, show. (Left) A rare example where all sources contribute significantly, with markers and tentative attributions marked. (Right) Three different situations describing the control of smog ozone production, all from the same geographic

  5. F-22 Pilot Heart Rate Response to +Gz and Relationship to Pilot Fitness Using U.S. Air Force Fitness Test Scores

    DTIC Science & Technology

    2015-08-19

    AFRL-SA-WP-SR-2015-0024 F-22 Pilot Heart Rate Response to +Gz and Relationship to Pilot Fitness Using U.S. Air Force Fitness Test Scores...To) July 2013 – June 2015 4. TITLE AND SUBTITLE F-22 Pilot Heart Rate Response to +Gz and Relationship to Pilot Fitness Using U.S. Air Force... Fitness Test Scores 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Marie-France M. McIntee, Mark J

  6. Experimental determination of the velocity and strain rate field in a laminar H2/Air counter-flow diffusion flame via LDA

    NASA Technical Reports Server (NTRS)

    Yeo, S. H.; Dancey, C. L.

    1991-01-01

    Measurements of the axial and radial components of velocity on the air side of stagnation in an axisymmetric H2/Air laminar counter-flow diffusion flame are reported. Results include the two-dimensional velocity field and computed velocity gradients (strain rates) along the stagnation streamline at two 'characteristic' strain rates, below the extinction limit. The measurements generally verify the modeling assumptions appropriate to the model of Kee et al. (1988). The 'traditional' potential flow model is not consistent with the measured results.

  7. What is an effective portable air cleaning device? A review.

    PubMed

    Shaughnessy, R J; Sextro, R G

    2006-04-01

    The use of portable air cleaning devices in residential settings has been steadily growing over the last 10 years. Three out of every 10 households now contain a portable air cleaning device. This increased use of air cleaners is accompanied by, if not influenced by, a fundamental belief by consumers that the air cleaners are providing an improved indoor air environment. However, there is a wide variation in the performance of air cleaners that is dependent on the specific air cleaner design and various indoor factors. The most widely used method in the United States to assess the performance of new air cleaners is the procedure described in the American National Standards Institute (ANSI)/Association of Home Appliance Manufacturers (AHAM) AC-1-2002. This method describes both the test conditions and the testing protocol. The protocol yields a performance metric that is based on the measured decay rate of contaminant concentrations with the air cleaner operating compared with the measured decay rate with the air cleaner turned off. The resulting metric, the clean air delivery rate (CADR), permits both an intercomparison of performance among various air cleaners and a comparison of air cleaner operation to other contaminant removal processes. In this article, we comment on the testing process, discuss its applicability to various contaminants, and evaluate the resulting performance metrics for effective air cleaning.

  8. General characteristics of U.S. Air Force and U.S. Army rated male and female aircrew.

    PubMed

    Voge, V M

    1996-11-01

    The issue of women flying military combat aircraft has been controversial. We conducted a comprehensive survey, via anonymous questionnaire, of all U.S. Army and U.S. Air Force rated female aircrew and an equal number of age- and duty-matched male aircrew. We are reporting on the general information section of the questionnaire here: age, time in the military, flight role, desire to remain in the military, marital status, number of children, spousal encouragement of career, type of aircraft flown, aircraft mishap and injury history, and reasons for extended period of illness/medical incapacitation to fly. Males' and females' responses in most areas surveyed were very similar. However, women were more than twice as likely to have been medically grounded for a period of more than 30 days. Not all the excess groundings were due to pregnancies. The responses to this section of the questionnaire indicate that female military officer aircrew are similar to their male counterparts. About 20% of married female aircrew do not postpone pregnancies in deference to their military careers.

  9. SU-E-P-15: Technique Factor Modulation and Reference Plane Air Kerma Rates in Response to Simulated Patient Thickness Variations for a Sample of Current Generation Fluoroscopes

    SciTech Connect

    Wunderle, K; Rakowski, J; Dong, F

    2015-06-15

    Purpose: To evaluate and compare approaches to technique factor modulation and air kerma rates in response to simulated patient thickness variations for four state-of-the-art and one previous-generation interventional fluoroscopes. Methods: A polymethyl methacrylate (PMMA) phantom was used as a tissue surrogate for the purposes of determining fluoroscopic reference plane air kerma rates, kVp, mA, and spectral filtration over a wide range of simulated tissue thicknesses. Data were acquired for each fluoroscopic and acquisition dose curve within a default abdomen or body imaging protocol. Results: The data obtained indicated vendor- and model-specific variations in the approach to technique factor modulation and reference plane air kerma rates across a range of tissue thicknesses. Some vendors have made hardware advances increasing the radiation output capabilities of their fluoroscopes; this was evident in the acquisition air kerma rates. However, in the imaging protocol evaluated, all of the state-of-the-art systems had relatively low air kerma rates in the fluoroscopic low-dose imaging mode as compared to the previous-generation unit. Each of the newest-generation systems also employ copper filtration in the selected protocol in the acquisition mode of imaging; this is a substantial benefit, reducing the skin entrance dose to the patient in the highest dose-rate mode of fluoroscope operation. Conclusion: Understanding how fluoroscopic technique factors are modulated provides insight into the vendor-specific image acquisition approach and provides opportunities to optimize the imaging protocols for clinical practice. The enhanced radiation output capabilities of some of the fluoroscopes may, under specific conditions, may be beneficial; however, these higher output capabilities also have the potential to lead to unnecessarily high dose rates. Therefore, all parties involved in imaging, including the clinical team, medical physicists, and imaging vendors, must work

  10. The impacts of short-term exposure to noise and traffic-related air pollution on heart rate variability in young healthy adults.

    PubMed

    Huang, Jing; Deng, Furong; Wu, Shaowei; Lu, Henry; Hao, Yu; Guo, Xinbiao

    2013-01-01

    Traffic-related air pollution and noise are associated with cardiovascular diseases, and alternation of heart rate variability (HRV), which reflects cardiac autonomic function, is one of the mechanisms. However, few studies considered the impacts of noise when exploring associations between air pollution and HRV. We explored whether noise modifies associations between short-term exposure to traffic-related air pollution and HRV in young healthy adults. In this randomized, crossover study, 40 young healthy adults stayed for 2 h in a traffic center and, on a separate occasion, in a park. Personal exposure to traffic-related air pollutants and noise were measured and ambulatory electrocardiogram was performed. Effects were estimated using mixed-effects regression models. Traffic-related air pollution and noise were both associated with HRV, and effects of air pollutants were amplified at high noise level (>65.6 A-weighted decibels (dB[A])) compared with low noise level (≤ 65.6 dB[A]). High frequency (HF) decreased by -4.61% (95% confidence interval, -6.75% to-2.42%) per 10 μg/m(3) increment in fine particle (PM2.5) at 5-min moving average, but effects became insignificant at low noise level (P>0.05). Similar effects modification was observed for black carbon (BC) and carbon monoxide (CO). We conclude that noise is an important factor influencing the effects of air pollution on HRV.

  11. Traffic-Related Air Pollution and Acute Changes in Heart Rate Variability and Respiratory Function in Urban Cyclists

    PubMed Central

    Kulka, Ryan; Dubeau, Aimee; Martin, Christina; Wang, Daniel; Dales, Robert

    2011-01-01

    Background: Few studies have examined the acute health effects of air pollution exposures experienced while cycling in traffic. Objectives: We conducted a crossover study to examine the relationship between traffic pollution and acute changes in heart rate variability. We also collected spirometry and exhaled nitric oxide measures. Methods: Forty-two healthy adults cycled for 1 hr on high- and low-traffic routes as well as indoors. Health measures were collected before cycling and 1–4 hr after the start of cycling. Ultrafine particles (UFPs; ≤ 0.1 μm in aerodynamic diameter), particulate matter ≤ 2.5 μm in aerodynamic diameter (PM2.5), black carbon, and volatile organic compounds were measured along each cycling route, and ambient nitrogen dioxide (NO2) and ozone (O3) levels were recorded from a fixed-site monitor. Mixed-effects models were used to estimate associations between air pollutants and changes in health outcome measures relative to precycling baseline values. Results: An interquartile range increase in UFP levels (18,200/cm3) was associated with a significant decrease in high-frequency power 4 hr after the start of cycling [β = –224 msec2; 95% confidence interval (CI), –386 to –63 msec2]. Ambient NO2 levels were inversely associated with the standard deviation of normal-to-normal (NN) intervals (β = –10 msec; 95% CI, –20 to –0.34 msec) and positively associated with the ratio of low-frequency to high-frequency power (β = 1.4; 95% CI, 0.35 to 2.5) 2 hr after the start of cycling. We also observed significant inverse associations between ambient O3 levels and the root mean square of successive differences in adjacent NN intervals 3 hr after the start of cycling. Conclusions: Short-term exposures to traffic pollution may contribute to altered autonomic modulation of the heart in the hours immediately after cycling. PMID:21672679

  12. Medium-Detail Delta Morphodynamic Modeling: Initial Experiments with Avulsion Behaviors, Sediment Delivery, Artificial Leeves, and Relative Sea Level Rise Rates

    NASA Astrophysics Data System (ADS)

    Ratliff, K. M.; Murray, A. B.; Hutton, E. W. H.; Piliouras, A.; Kim, W.

    2014-12-01

    Deltas and their flat, fertile lands have become the most densely populated places on earth, but, partly because of anthropogenic interactions with fluvial, coastal, and wetland processes, their inhabitants are increasingly susceptible to natural disasters. Humans have decreased sediment supply delivered to rivers and ultimately wetlands and the coast, causing accelerating subsidence. The natural course and processes of many rivers have been altered through channelization, artificial levees, and dams, which 'perch' the river above its floodplain. As the rate of relative sea-level rise (RSLR) increases, so will surface aggradation and channel backfilling, resulting in a fluvial system that is more vulnerable to flooding and frequent avulsions. To investigate the effects of increasing RSLR and anthropogenic manipulations on delta morphodynamics, we create new avulsion and floodplain modules to couple with the 3D mode of Sedflux (Hutton and Syvitski, 2008), a stratigraphic basin-filling model. We replace the probabilistic approach of channel avulsion previously used in the model with a module incorporating the steepest-decent methodology used in Jerolmack and Paola (2007), and a floodplain algorithm to deposit sediment on subaerial cells. Model experiments with Sedflux and the new modules address the effects on delta morphodynamics of varying rates of RSLR (affecting base-level), changes in sediment delivery (adjusting the upstream boundary conditions), and restriction of natural fluvial dynamics (inhibiting avulsions). The work presented here is the first step in a more expansive project to develop a new 3D eco-morphodynamic delta model system that will be based on further model couplings, including a vegetation module (that will affect fluvial and floodplain dynamics) and a coastline module (that will re-work the shoreline based on wave-driven alongshore sediment transport). The model system results will be tested and calibrated based on comparisons with

  13. Heating rate measurements over 30 deg and 40 deg (half angle) blunt cones in air and helium in the Langley expansion tube facility

    NASA Technical Reports Server (NTRS)

    Reddy, N. M.

    1980-01-01

    Convective heat transfer measurements, made on the conical portion of spherically blunted cones (30 deg and 40 deg half angle) in an expansion tube are discussed. The test gases used were helium and air; flow velocities were about 6.8 km/sec for helium and about 5.1 km/sec for air. The measured heating rates are compared with calculated results using a viscous shock layer computer code. For air, various techniques to determine flow velocity yielded identical results, but for helium, the flow velocity varied by as much as eight percent depending on which technique was used. The measured heating rates are in satisfactory agreement with calculation for helium, assuming the lower flow velocity, the measurements are significantly greater than theory and the discrepancy increased with increasing distance along the cone.

  14. Effects of H2O, CO2, and N2 Air Contaminants on Critical Airside Strain Rates for Extinction of Hydrogen-Air Counterflow Diffusion Flames

    NASA Technical Reports Server (NTRS)

    Pellett, G. L.; Wilson, L. G.; Northam, G. B.; Guerra, Rosemary

    1989-01-01

    Coaxial tubular opposed jet burners (OJB) were used to form dish shaped counterflow diffusion flames (CFDF), centered by opposing laminar jets of H2, N2 and both clean and contaminated air (O2/N2 mixtures) in an argon bath at 1 atm. Jet velocities for flame extinction and restoration limits are shown versus wide ranges of contaminant and O2 concentrations in the air jet, and also input H2 concentration. Blowoff, a sudden breaking of CFDF to a stable ring shape, occurs in highly stretched stagnation flows and is generally believed to measure kinetically limited flame reactivity. Restore, a sudden restoration of central flame, is a relatively new phenomenon which exhibits a H2 dependent hysteresis from Blowoff. For 25 percent O2 air mixtures, mole for mole replacement of 25 percent N2 contaminant by steam increased U(air) or flame strength at Blowoff by about 5 percent. This result is consistent with laminar burning velocity results from analogous substitution of steam for N2 in a premixed stoichiometric H2-O2-N2 (or steam) flame, shown by Koroll and Mulpuru to promote a 10 percent increase in experimental and calculated laminar burning velocity, due to enhanced third body efficiency of water in: H + O2 + M yields HO2 + M. When the OJB results were compared with Liu and MacFarlane's experimental laminar burning velocity of premixed stoichiometric H2 + air + steam, a crossover occurred, i.e., steam enhanced OJB flame strength at extinction relative to laminar burning velocity.

  15. Measurement of air kerma rates for 6- to 7-MeV high-energy gamma-ray field by ionisation chamber and build-up plate.

    PubMed

    Kowatari, Munehiko; Tanimura, Yoshihiko; Tsutsumi, Masahiro

    2014-12-01

    The 6- to 7-MeV high-energy gamma-ray calibration field by the (19)F(p, αγ)(16)O reaction is to be served at the Japan Atomic Energy Agency. For the determination of air kerma rates using an ionisation chamber in the 6- to 7-MeV high-energy gamma-ray field, the establishment of the charged particle equilibrium must be achieved during measurement. In addition to measurement of air kerma rates by the ionisation chamber with a thick build-up cap, measurement using the ionisation chamber and a build-up plate (BUP) was attempted, in order to directly determine air kerma rates under the condition of regular calibration for ordinary survey meters and personal dosemeters. Before measurements, Monte Carlo calculations were made to find the optimum arrangement of BUP in front of the ionisation chamber so that the charged particle equilibrium could be well established. Measured results imply that air kerma rates for the 6- to 7-MeV high-energy gamma-ray field could be directly determined under the appropriate condition using an ionisation chamber coupled with build-up materials.

  16. Effect of air flow rate on the polyphenols content and antioxidant capacity of convective dried cactus pear cladodes (Opuntia ficus indica).

    PubMed

    Gallegos-Infante, José-Alberto; Rocha-Guzman, Nuria-Elizabeth; González-Laredo, Ruben-Francisco; Reynoso-Camacho, Rosalia; Medina-Torres, Luis; Cervantes-Cardozo, Veronica

    2009-01-01

    The interest in nopal has encouraged the use of dehydration; there are few studies about the effect of process parameters on the nopal polyphenol content and antioxidant activity. The objective of the present work was to evaluate the effect of air-drying flow rates on the amount and antioxidant capacity of extracts of Opuntia ficus indica cladodes. Nopal was dried at 45 degrees C and air flow rates of 3 and 5 m/sec. Samples were analyzed for moisture, total polyphenol, flavonoid, and flavonol contents, chain-breaking activity, inhibition of low-density lipoprotein and deoxyribose oxidation. Nopal drying at an air flow rate of 3 m/sec showed higher values of phenols, flavonoids and flavonols. The best value of low-density lipoprotein inhibition and deoxyribose was found at 1,000 microg/ml. The air flow rate affected the amount of polyphenols and the OH( . ) radical scavenging, but did not modify the chain-breaking activity and the low-density lipoprotein inhibition activity.

  17. Experimental study on burning rates of square/rectangular gasoline and methanol pool fires under longitudinal air flow in a wind tunnel.

    PubMed

    Hu, L H; Liu, S; Peng, W; Huo, R

    2009-09-30

    Square pool fires with length of 5, 7.5, 10, 15, 20, 25 and 30 cm and rectangular pool fires with dimensions of 10 cm x 20 cm and 10 cm x 40 cm were burned in a wind tunnel, under a longitudinal air flow ranged from 0 to 3m/s with incremental change of about 0.5m/s. Methanol and gasoline were burned and compared, with results indicated that their burning rates showed different response to the longitudinal air flow. With the increase of the longitudinal air flow speed, the burning rates of methanol pool fires, except the 5 cm square one, first decreased and then increased, but those of the 5 cm methanol square one and the gasoline pool fires increased monotonously. The burning rate of smaller square pool fires increased more significantly than that of the larger ones, as well as the enlargement of their flame attachment length along the ground. The burning rate of a rectangular pool fire with longer rim parallel to the longitudinal flow increased faster, but the flame attachment length seemed to increase more gradually, with the increase of the longitudinal air flow speed than that perpendicular to.

  18. Chemical Abstracts' Document Delivery Service.

    ERIC Educational Resources Information Center

    Rollins, Stephen

    1984-01-01

    The Document Delivery Service offered by Chemical Abstracts is described in terms of the DIALORDER option on the Dialog information retrieval system, mail requests, and requests transmitted through OCLC's Interlibrary Loan system. Transmission costs, success rates, delivery rates, and other considerations in utilizing the service are included.…

  19. Using numerical simulation methods to predict the effects of balancing coal and primary air flow rates on furnace emissions

    SciTech Connect

    Schwab, M.J.; Nelson, R.K.; Hardman, R.R.; Facchiano, T.

    1996-12-31

    This paper presents the technical results of a computer modeling exercise to quantify the impacts of balanced and unbalanced coal flows on NO{sub x} emissions and other boiler performance indicators. Using Airflow Sciences Corporation`s proprietary codes, separate computational fluid dynamics models of the furnace region and coal nozzles of a 200 MW{sub e} tangentially-fired boiler equipped with an ABB C-E Services Low NO{sub x} Concentric Firing System (Level II) were constructed. In modeling the coal combustion process, the numerical simulation of gas conditions within the furnace is accomplished by coupling the fluid dynamics relationships with sub-models that predict heat transfer (conduction, convection and radiation), turbulence, coal particle trajectories and temperatures, coal devolatilization, char combustion and equilibrium (mixing limited) chemistry. The equilibrium chemistry sub-model defines concentrations of the products of combustion at all locations within the furnace, with the exception of NO{sub x} concentrations. The generation of NO{sub x} is decoupled from the CFD simulation and is determined using finite-rate chemistry. The model was validated using test results from a recently completed US Department of Energy-sponsored Clean Coal Project at Gulf Power Company`s Plant Lansing Smith Unit 2. Validation was accomplished through comparison of the model results with experimental data including NO{sub x} emissions, unburned carbon, furnace exit gas temperatures, carbon monoxide levels, and excess oxygen values. Following validation, additional simulations were run to quantify the effect of balanced and unbalanced coal flows. Conditions simulated included the as-found condition, a fully balanced condition, a mill-by-mill fully balanced condition, and a {+-}10 percent balanced condition. The results showed that NO{sub x} emissions were not significantly affected by improving the distributions of primary air and coal between the burners.

  20. Fluid delivery control system

    SciTech Connect

    Hoff, Brian D.; Johnson, Kris William; Algrain, Marcelo C.; Akasam, Sivaprasad

    2006-06-06

    A method of controlling the delivery of fluid to an engine includes receiving a fuel flow rate signal. An electric pump is arranged to deliver fluid to the engine. The speed of the electric pump is controlled based on the fuel flow rate signal.

  1. [Effect of past abortions and the sequence of gestations on the course of the next pregnancy and labor as well as the state-at-delivery, maturity, dystrophia and mortality rate of the newborn infants].

    PubMed

    Osuch-Jaczewska, R; Tomala, J

    1979-02-01

    Legal abortions have reduced the number of miscarriages by 20%, and of abandoned children by 56%; but at the same time, can be hazardous to the mother both initially (loss of blood, punctured uterus, damaged cervix) and later (infections in the reproductive system, infertility, extrauterine pregnancy, psychological disorders). From 1968 to 1975, 12,795 mothers and their newborns were studied: group 1 (24.8%), were mothers who have had abortions prior to 1st delivery; group 2 (42.3%), mothers having a first delivery with no previous miscarriages or abortions; and group 3 (32.9%), mothers of 2 or more children who had abortions afterwards. Abortion prior to first delivery increased the number of complications (54.4%) during pregnancy (liver and kidney problems, bacterial and viral infections), and during delivery (dirty amniotic fluid, bag of waters ruptured prematurely, pathology of the placenta and membranes, pathology of the umbilical cord). 10% of the deliveries where the mother had a previous history of abortion required medical intervention. Intrauterine dystrophy had occurred in 17% cases and the incidence of premature births was greater, 16%. 29.2% of the infants were in poor condition at delivery according to the Apgar scale (under 4 points) and 42.4% manifested disturbances in environment adaptability. The neonatal mortality rate 6.6% was twice that of the infants from the other 2 groups. The authors conclude that abortions are a threat to the health of mothers and during subsequent pregnancies, endanger the fetus and the newborn. Abortion cannot be regarded as a means of family planning. (Summaries in RUS, ENG).

  2. Temperature and pressure influence on maximum rates of pressure rise during explosions of propane-air mixtures in a spherical vessel.

    PubMed

    Razus, D; Brinzea, V; Mitu, M; Movileanu, C; Oancea, D

    2011-06-15

    The maximum rates of pressure rise during closed vessel explosions of propane-air mixtures are reported, for systems with various initial concentrations, pressures and temperatures ([C(3)H(8)]=2.50-6.20 vol.%, p(0)=0.3-1.3 bar; T(0)=298-423 K). Experiments were performed in a spherical vessel (Φ=10 cm) with central ignition. The deflagration (severity) index K(G), calculated from experimental values of maximum rates of pressure rise is examined against the adiabatic deflagration index, K(G, ad), computed from normal burning velocities and peak explosion pressures. At constant temperature and fuel/oxygen ratio, both the maximum rates of pressure rise and the deflagration indices are linear functions of total initial pressure, as reported for other fuel-air mixtures. At constant initial pressure and composition, the maximum rates of pressure rise and deflagration indices are slightly influenced by the initial temperature; some influence of the initial temperature on maximum rates of pressure rise is observed only for propane-air mixtures far from stoichiometric composition. The differentiated temperature influence on the normal burning velocities and the peak explosion pressures might explain this behaviour.

  3. 19 CFR 19.39 - Delivery for exportation.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 19 Customs Duties 1 2011-04-01 2011-04-01 false Delivery for exportation. 19.39 Section 19.39... Delivery for exportation. (a) Delivery to land border locations—(1) Land border locations. Land border... not including departure to a contiguous country by air or sea. Deliveries from a duty-free store...

  4. Counterflow diffusion flames of hydrogen, and hydrogen plus methane, ethylene, propane, and silane vs. air - Strain rates at extinction

    NASA Technical Reports Server (NTRS)

    Pellett, G. L.; Northam, G. Burton; Wilson, L. G.

    1991-01-01

    Five coaxial tubular opposed jet burners (OJBs) with tube diameter D(T) of 1.8-10 mm and 5 mm conical nozzles were used to form dish-shaped counterflow diffusion flames centered by opposing laminar jets of nitrogen and hydrocarbon-diluted H2 versus air in an argon-purged chamber at 1 atm. Area-averaged air jet velocities at blowoff of the central flame, U(air), characterized extinction of the airside flame as functions of input H2 concentration on the fuelside. A master plot of extensive U(air) data at blowoff versus D(T) shows that U(air) varies linearly with D(T). This and other data sets are used to find that nozzle OJB results for U(air)/diameter average 4.24 + or - 0.28 times larger than tubular OJB results for the same fuel compositions. Critical radial velocity gradients consistent with one-dimensional stagnation point boundary theory and with plug flow inputs are estimated. The results compare favorably with published numerical results based only on potential flow.

  5. Rationale for the selection of an aerosol delivery system for gene delivery.

    PubMed

    Lentz, Yvonne K; Anchordoquy, Thomas J; Lengsfeld, Corinne S

    2006-01-01

    Genetic therapeutics show great promise toward the treatment of illnesses associated with the lungs; however, current methods of delivery such as jet and ultrasonic nebulization decrease the activity and effectiveness of these treatments. Extremely low transfection rates exhibited by non-complexed plasmid DNA in these nebulizers have been primarily attributed to poor translocation and loss of molecular integrity as a consequence of shear-induced degradation. Current research focusing on methods to increase transfection rates via the pulmonary delivery route has largely concentrated on the incorporation of carbon dioxide in the air stream to increase breath depth as well as the addition of cationic agents that condense DNA into compact, ordered complexes. The purpose of this study was to examine the impact of several classic as well as the latest atomization devices on the structure of non-complexed DNA. Various sizes of plasmid and cosmid DNA were processed through an electrostatic spray, ultrasonic nebulizer, vibrating mesh nebulizer, and jet nebulizer. Results varied dramatically based upon atomization device as well as DNA size. This may explain the inefficiency experienced by genetic therapeutics during pulmonary delivery. More importantly, this suggests that the selection of an atomization device should consider DNA size in order to achieve optimal gene delivery to the lungs.

  6. Determination of air-kerma strength for the {sup 192}Ir GammaMedplus iX pulsed-dose-rate brachytherapy source

    SciTech Connect

    Riley, A. D.; Pike, T. L.; Micka, J. A.; Fulkerson, R. K.; DeWerd, L. A.

    2013-07-15

    Purpose: Pulsed-dose-rate (PDR) brachytherapy was originally proposed to combine the therapeutic advantages of high-dose-rate (HDR) and low-dose-rate brachytherapy. Though uncommon in the United States, several facilities employ pulsed-dose-rate brachytherapy in Europe and Canada. Currently, there is no air-kerma strength standard for PDR brachytherapy {sup 192}Ir sources traceable to the National Institute of Standards and Technology. Discrepancies in clinical measurements of the air-kerma strength of the PDR brachytherapy sources using HDR source-calibrated well chambers warrant further investigation.Methods: In this research, the air-kerma strength for an {sup 192}Ir PDR brachytherapy source was compared with the University of Wisconsin Accredited Dosimetry Calibration Laboratory transfer standard well chambers, the seven-distance technique [B. E. Rasmussen et al., 'The air-kerma strength standard for 192Ir HDR sources,' Med. Phys. 38, 6721-6729 (2011)], and the manufacturer's stated value. Radiochromic film and Monte Carlo techniques were also employed for comparison to the results of the measurements.Results: While the measurements using the seven-distance technique were within + 0.44% from the manufacturer's determination, there was a + 3.10% difference between the transfer standard well chamber measurements and the manufacturer's stated value. Results showed that the PDR brachytherapy source has geometric and thus radiological qualities that exhibit behaviors similar to a point source model in contrast to a conventional line source model.Conclusions: The resulting effect of the pointlike characteristics of the PDR brachytherapy source likely account for the differences observed between well chamber and in-air measurements.

  7. Effects of H2O, CO2, and N2 air contaminants on critical airside strain rates for extinction of hydrogen-air counterflow diffusion flames

    NASA Technical Reports Server (NTRS)

    Pellett, G. L.; Northam, G. B.; Wilson, L. G.; Guerra, Rosemary

    1989-01-01

    Dish-shaped counterflow diffusion flames centered by opposing laminar jets of H2 and clean and contaminant O2/N2 mixtures in an argon bath at 1 atm were used to study the effects of contaminants on critical airside strain. The jet velocities for both flame extinction and restoration are found for a wide range of contaminant and O2 concentrations in the air jet. The tests are also conducted for a variety of input H2 concentrations. The results are compared with those from several other studies.

  8. Contemporary-use pesticides in personal air samples during pregnancy and blood samples at delivery among urban minority mothers and newborns.

    PubMed Central

    Whyatt, Robin M; Barr, Dana B; Camann, David E; Kinney, Patrick L; Barr, John R; Andrews, Howard F; Hoepner, Lori A; Garfinkel, Robin; Hazi, Yair; Reyes, Andria; Ramirez, Judyth; Cosme, Yesenia; Perera, Frederica P

    2003-01-01

    We have measured 29 pesticides in plasma samples collected at birth between 1998 and 2001 from 230 mother and newborn pairs enrolled in the Columbia Center for Children's Environmental Health prospective cohort study. Our prior research has shown widespread pesticide use during pregnancy among this urban minority cohort from New York City. We also measured eight pesticides in 48-hr personal air samples collected from the mothers during pregnancy. The following seven pesticides were detected in 48-83% of plasma samples (range, 1-270 pg/g): the organophosphates chlorpyrifos and diazinon, the carbamates bendiocarb and 2-isopropoxyphenol (metabolite of propoxur), and the fungicides dicloran, phthalimide (metabolite of folpet and captan), and tetrahydrophthalimide (metabolite of captan and captafol). Maternal and cord plasma levels were similar and, except for phthalimide, were highly correlated (p < 0.001). Chlorpyrifos, diazinon, and propoxur were detected in 100% of personal air samples (range, 0.7-6,010 ng/m(3)). Diazinon and propoxur levels were significantly higher in the personal air of women reporting use of an exterminator, can sprays, and/or pest bombs during pregnancy compared with women reporting no pesticide use or use of lower toxicity methods only. A significant correlation was seen between personal air level of chlorpyrifos, diazinon, and propoxur and levels of these insecticides or their metabolites in plasma samples (maternal and/or cord, p < 0.05). The fungicide ortho-phenylphenol was also detected in 100% of air samples but was not measured in plasma. The remaining 22 pesticides were detected in 0-45% of air or plasma samples. Chlorpyrifos, diazinon, propoxur, and bendiocarb levels in air and/or plasma decreased significantly between 1998 and 2001. Findings indicate that pesticide exposures are frequent but decreasing and that the pesticides are readily transferred to the developing fetus during pregnancy. PMID:12727605

  9. The effects of indoor particle exposure on blood pressure and heart rate among young adults: An air filtration-based intervention study

    NASA Astrophysics Data System (ADS)

    Lin, Lian-Yu; Chen, Hua-Wei; Su, Te-Li; Hong, Gui-Bing; Huang, Li-Chu; Chuang, Kai-Jen

    2011-10-01

    This study aims to evaluate whether air filtration can modify the effect of indoor particles on blood pressure (BP) and heart rate (HR) in a young, healthy population. We recruited 60 students to participate in a study of multiple, prolonged exposures to either particle-filtered or non-filtered indoor air. We made four home visits in which we took continuous 48-hour measurements of systolic BP (SBP), diastolic BP (DBP), and HR in each participant. Particulate matter less than 2.5 μm in diameter (PM 2.5) and total volatile organic compounds (VOCs) were measured at each participant's home. We used mixed-effects models to associate BP and HR with indoor particles and total VOCs, which were averaged over 1-hour to 8-hour periods prior to physiological measurements. We found that the mean values for indoor PM 2.5 exposures at 1-hour to 4-hour were associated with an elevation in SBP, DBP and HR. The effects of indoor PM 2.5 on BP and HR were greatest during the visits without air filtration. During visits with air filtration, participants showed no significant change in BP and HR in response to indoor PM 2.5 exposure. We concluded that air filtration can reduce indoor PM 2.5 concentrations and modify the effect of PM 2.5 on BP and HR in a healthy, young population.

  10. Comparison of injection pain, heart rate increase, and postinjection pain of articaine and lidocaine in a primary intraligamentary injection administered with a computer-controlled local anesthetic delivery system.

    PubMed Central

    Nusstein, John; Berlin, Jeffrey; Reader, Al; Beck, Mike; Weaver, Joel M.

    2004-01-01

    The purpose of this prospective, randomized, double-blind study was to compare the pain of injection, heart rate increase, and postinjection pain of the intraligamentary injection of 4% articaine with 1:100,000 epinephrine and 2% lidocaine with 1:100,000 epinephrine administered with a computer-controlled local anesthetic delivery system. Using a crossover design, intraligamentary injections of 1.4 mL of 4% articaine with 1:100,000 epinephrine and 1.4 mL of 2% lidocaine with 1:100,000 epinephrine were randomly administered on the mesial and distal aspects of the mandibular first molar with a computer-controlled local anesthetic delivery system in a double-blind manner at 2 separate appointments to 51 subjects. The results demonstrated the incidence of moderate pain was 14%-27% with needle insertion, with 0%-4% reporting severe pain. For solution deposition, moderate pain was reported 8%-18% of the time, with no reports of severe pain. There were no significant differences between the articaine and lidocaine solutions. Regarding heart rate changes, neither anesthetic solution resulted in a significant increase in heart rate over baseline readings. On day 1 postinjection, there was a 31% incidence of moderate/severe pain with the articaine solution and 20% incidence of moderate/severe pain with the lidocaine solution. The moderate/severe pain ratings decreased over the next 2 days. There were no significant differences between the articaine and lidocaine solutions. We concluded that the intraligamentary injection of 4% articaine with 1:100,000 epinephrine was similar to 2% lidocaine with 1:100,000 epinephrine for injection pain and postinjection pain in the mandibular first molar when administered with a computer-controlled local anesthetic delivery system. For both anesthetic solutions, heart rate did not significantly increase with the intraligamentary injection using the computer-controlled local anesthetic system. PMID:15675261

  11. Relationship between low tube voltage (70 kV) and the iodine delivery rate (IDR) in CT angiography: An experimental in-vivo study

    PubMed Central

    Pietsch, Hubertus; Korporaal, Johannes G.; Haberland, Ulrike; Mahnken, Andreas H.; Flohr, Thomas G.; Uder, Michael; Jost, Gregor

    2017-01-01

    Objective Very short acquisition times and the use of low-kV protocols in CTA demand modifications in the contrast media (CM) injection regimen. The aim of this study was to optimize the use of CM delivery parameters in thoraco-abdominal CTA in a porcine model. Materials and methods Six pigs (55–68 kg) were examined with a dynamic CTA protocol (454 mm scan length, 2.5 s temporal resolution, 70 s total acquisition time). Four CM injection protocols were applied in a randomized order. 120 kV CTA protocol: (A) 300 mg iodine/kg bodyweight (bw), IDR = 1.5 g/s (flow = 5 mL/s), injection time (ti) 12 s (60 kg bw). 70 kV CTA protocols: 150 mg iodine/kg bw: (B) IDR = 0.75 g/s (flow = 2.5 mL/s), ti = 12 s (60 kg bw); (C) IDR = 1.5 g/s (flow = 5 mL/s), ti = 12 s (60 kg bw); (D) IDR = 3.0 g/s (flow = 10 mL/s), ti = 3 s (60 kg bw). The complete CM bolus shape was monitored by creating time attenuation curves (TAC) in different vascular territories. Based on the TAC, the time to peak (TTP) and the peak enhancement were determined. The diagnostic window (relative enhancement > 300 HU), was calculated and compared to visual inspection of the corresponding CTA data sets. Results The average relative arterial peak enhancements after baseline correction were 358.6 HU (A), 356.6 HU (B), 464.0 HU (C), and 477.6 HU (D). The TTP decreased with increasing IDR and decreasing ti, protocols A and B did not differ significantly (systemic arteries, p = 0.843; pulmonary arteries, p = 0.183). The delay time for bolus tracking (trigger level 100 HU; target enhancement 300 HU) for single-phase CTA was comparable for protocol A and B (3.9, 4.3 s) and C and D (2.4, 2.0 s). The scan window time frame was comparable for the different protocols by visual inspection of the different CTA data sets and by analyzing the TAC. Conclusions All protocols provided sufficient arterial enhancement. The use of a 70 kV CTA protocol is recommended because of a 50% reduction of total CM volume and a 50% reduced

  12. The study of mercury exchange rate between air and soil surface in Hongfeng reservoir region, Guizhou, PR China

    NASA Astrophysics Data System (ADS)

    Wang, S.; Feng, X.; Qiu, G.

    2003-05-01

    In summer of 2002, we measured the exchange flux of mercury between air and soil surface using the method of Dynamic Flux Chamber (DFC) in Hongfeng lake region. At the same time, we recorded meteorological parameters such as air temperature, soil temperature, wind speed and solar radiation using a multi-function mini-weather station (global water III). Soil, moss and fertilizer samples in study area were also collected. The Hg fluxes of air/soil surface rangeed from -11.0ng m^{-2} h^{-1} to 219.0ng m^{-2}h^{-1}, averaged at 29.2 ng m^{-2} h^{-1} (n = 508). The data show that the exchange of mercury is bi-direction between air and soit surface: namely both emission and deposition of mercury occurs, but Hg emission is much more frequent than deposition process (n_{deposition} =3,n_{emission}= 505). The average mercury content in soil, moss, fertilizer sample are 249.9± 24.1ng/g (n=3), 450.4 ± 64.6ng/g (n=2), 53.4ng/g (n= 1) respectively.

  13. Sensor for Individual Burner Control of Coal Firing Rate, Fuel-Air Ratio and Coal Fineness Correlation

    SciTech Connect

    R. Demler

    2006-04-01

    Accurate, cost-efficient monitoring instrumentation has long been considered essential to the operation of power plants. Nonetheless, for the monitoring of coal flow, such instrumentation has been sorely lacking and technically difficult to achieve. With more than half of the electrical power in the United States currently supplied by coal, energy generated by this resource is critical to the US economy. The demand for improvement in this area has only increased as a result of the following two situations: First, deregulation has produced a heightened demand for both reduced electrical cost and improved grid connectivity. Second, environmental concerns have simultaneously resulted in a need for both increased efficiency and reduced carbon and NOx emissions. A potential approach to addressing both these needs would be improvement in the area of combustion control. This would result in a better heat rate, reduced unburned carbon in ash, and reduced NOx emissions. However, before feedback control can be implemented, the ability to monitor coal flow to the burners in real-time must be established. While there are several ''commercially available'' products for real-time coal flow measurement, power plant personnel are highly skeptical about the accuracy and longevity of these systems in their current state of development. In fact, following several demonstration projects of in-situ coal flow measurement systems in full scale utility boilers, it became obvious that there were still many unknown influences on these instruments during field applications. Due to the operational environment of the power plant, it has been difficult if not impossible to sort out what parameters could be influencing the various probe technologies. Additionally, it has been recognized for some time that little is known regarding the performance of coal flow splitters, even where rifflers are employed. Often the coal flow distribution from these splitters remains mal-distributed. There have

  14. Metrology for drug delivery.

    PubMed

    Lucas, Peter; Klein, Stephan

    2015-08-01

    In various recently published studies, it is argued that there are underestimated risks with infusion technology, i.e., adverse incidents believed to be caused by inadequate administration of the drugs. This is particularly the case for applications involving very low-flow rates, i.e., <1 ml/h and applications involving drug delivery by means of multiple pumps. The risks in infusing are caused by a lack of awareness, incompletely understood properties of the complete drug delivery system and a lack of a proper metrological infrastructure for low-flow rates. Technical challenges such as these were the reason a European research project "Metrology for Drug Delivery" was started in 2011. In this special issue of Biomedical Engineering, the results of that project are discussed.

  15. Forceps Delivery

    MedlinePlus

    ... provider might limit the amount of time you push. Your baby is facing the wrong direction. A forceps delivery might be needed if your baby is facing up (occiput posterior position) rather than down (occiput anterior ...

  16. Delivery presentations

    MedlinePlus

    ... page: //medlineplus.gov/ency/patientinstructions/000621.htm Delivery presentations To use the sharing features on this page, ... baby by cesarean birth (C-section) . Less Common Presentations With the brow-first position, the baby's head ...

  17. The effect of fission products on the rate of U3O8 formation in SIMFUEL oxidized in air at 250°C

    NASA Astrophysics Data System (ADS)

    Choi, Jong-Won; McEachern, Rod J.; Taylor, Peter; Wood, Donald D.

    1996-06-01

    The effect of fission products on the rate of U3O8 formation was investigated by oxidizing UO2-based SIMFUEL (simulated high burnup nuclear fuel) and unirradiated UO2 fuel specimens in air at 250°C for different times (1-317 days). The progress of oxidation was monitored by X-ray diffraction, revealing that the rate of U3O8 formation declines with increasing burnup. An expression was derived to describe quantitatively the time for U3O8 powder formation as a function of simulated burnup. These findings were supported by additional isochronal oxidation experiments conducted between 200 and 300°C.

  18. Death rate in a small air-lift loop reactor of vero cells grown on solid microcarriers and in macroporous microcarriers.

    PubMed

    Martens, D E; Nollen, E A; Hardeveld, M; Velden-de Groot, C A; Gooijer, C D; Beuvery, E C; Tramper, J

    1997-01-01

    The death rate of Vero cells grown on Cytodex-3 microcarrierswas studied as a function of the gas flow rate in a smallair-lift loop reactor. The death rate may be described byfirst-order death-rate kinetics. The first-order death-rateconstant as calculated from the decrease in viable cells, theincrease in dead cells and the increase in LDH activity islinear proportional to the gas flow rate, with a specifichypothetical killing volume in which all cells are killed ofabout 2.10(-3)m(3) liquid per m(3) of air bubbles.In addition, an experiment was conducted in the sameair-lift reactor with Vero cells grown inside porous Asahimicrocarriers. The specific hypothetical killing volumecalculated from this experiment has a value of 3.10(-4)m(3) liquid per m(3) of air bubbles, which shows thatthe porous microcarriers were at least in part able to protectthe cells against the detrimental hydrodynamic forcesgenerated by the bubbles.

  19. Improving the Quality of Student Ratings of Instruction: A Look at Two Strategies. AIR 1988 Annual Forum Paper.

    ERIC Educational Resources Information Center

    Cook, Stuart S.

    The effect of rating scale format (behaviorally anchored rating scales (BARS) and Likert) and rater training on leniency and halo in student ratings of instruction was investigated. The subjects (N=269) were students enrolled in required courses at a graduate theological seminary in the southwestern United States. A repeated measures design…

  20. A Simulation of the Effects of Varying Repetition Rate and Pulse Width of Nanosecond Discharges on Premixed Lean Methane-Air Combustion

    DOE PAGES

    Bak, Moon Soo; Cappelli, Mark A.

    2012-01-01

    Two-dimensional kinetic simulation has been carried out to investigate the effects of repetition rate and pulse width of nanosecond repetitively pulsed discharges on stabilizing premixed lean methane-air combustion. The repetition rate and pulse width are varied from 10 kHz to 50 kHz and from 9 ns to 2 ns while the total power is kept constant. The lower repetition rates provide larger amounts of radicals such as O, H, and OH. However, the effect on stabilization is found to be the same for all of the tested repetition rates. The shorter pulse width is found to favor the production of species in higher electronicmore » states, but the varying effects on stabilization are also found to be small. Our results indicate that the total deposited power is the critical element that determines the extent of stabilization over this range of discharge properties studied.« less

  1. An integrated evaluation study of the ventilation rate, the exposure and the indoor air quality in naturally ventilated classrooms in the Mediterranean region during spring.

    PubMed

    Dorizas, Paraskevi Vivian; Assimakopoulos, Margarita-Niki; Helmis, Constantinos; Santamouris, Mattheos

    2015-01-01

    Ventilation rates and indoor air pollutants have been extensively monitored in nine naturally ventilated primary schools of Athens, Greece during spring. The ventilation rates and pollutant levels were studied during the teaching and non-teaching periods and ventilation profiles were created for each of the schools. The median ventilation rates per school ranged between 0.7 and 8 ACH while the average ventilation rate in all schools (11.7l/s/p) was greater than the minimum recommended rates by ASHRAE for school classrooms. The average carbon dioxide (CO2) concentrations per school varied between 893 and 2082ppm, while the majority of the cases were slightly above the recommended limit values. CO2 concentrations were also positively correlated to the number of students and negatively correlated to the ventilation rates. Particles of several size ranges (PM10, PM5, PM2.5, PM1, PM0.5 and UFP) were also measured and analyzed. PM10 concentrations exceeded the recommended limit values by more than 10 times for the majority of the cases. There were also many cases that the PM2.5 concentrations exceeded their limit values. PM concentrations were significantly affected by the ventilation rates and the presence of students. All of the measured particle sizes were greater during teaching than the non-teaching hours. For most of the cases the indoor to outdoor (I/O) concentrations ratios of PM10 and PM2.5 were much greater than one, indicating that the indoor environment was being mostly affected by indoor sources instead of the outdoor air. Furthermore it was found that chalk and marker boards' usage significantly affect indoor pollutant concentrations. Overall, the measured levels of exposure were for most of the cases greater than the recommended guideline values due to the intense presence of indoor pollution sources, even though the ventilation rates were in general satisfactory.

  2. Simplified Two-Time Step Method for Calculating Combustion Rates and Nitrogen Oxide Emissions for Hydrogen/Air and Hydorgen/Oxygen

    NASA Technical Reports Server (NTRS)

    Molnar, Melissa; Marek, C. John

    2005-01-01

    A simplified single rate expression for hydrogen combustion and nitrogen oxide production was developed. Detailed kinetics are predicted for the chemical kinetic times using the complete chemical mechanism over the entire operating space. These times are then correlated to the reactor conditions using an exponential fit. Simple first order reaction expressions are then used to find the conversion in the reactor. The method uses a two-time step kinetic scheme. The first time averaged step is used at the initial times with smaller water concentrations. This gives the average chemical kinetic time as a function of initial overall fuel air ratio, temperature, and pressure. The second instantaneous step is used at higher water concentrations (> 1 x 10(exp -20) moles/cc) in the mixture which gives the chemical kinetic time as a function of the instantaneous fuel and water mole concentrations, pressure and temperature (T4). The simple correlations are then compared to the turbulent mixing times to determine the limiting properties of the reaction. The NASA Glenn GLSENS kinetics code calculates the reaction rates and rate constants for each species in a kinetic scheme for finite kinetic rates. These reaction rates are used to calculate the necessary chemical kinetic times. This time is regressed over the complete initial conditions using the Excel regression routine. Chemical kinetic time equations for H2 and NOx are obtained for H2/air fuel and for the H2/O2. A similar correlation is also developed using data from NASA s Chemical Equilibrium Applications (CEA) code to determine the equilibrium temperature (T4) as a function of overall fuel/air ratio, pressure and initial temperature (T3). High values of the regression coefficient R2 are obtained.

  3. Summary of Simplified Two Time Step Method for Calculating Combustion Rates and Nitrogen Oxide Emissions for Hydrogen/Air and Hydrogen/Oxygen

    NASA Technical Reports Server (NTRS)

    Marek, C. John; Molnar, Melissa

    2005-01-01

    A simplified single rate expression for hydrogen combustion and nitrogen oxide production was developed. Detailed kinetics are predicted for the chemical kinetic times using the complete chemical mechanism over the entire operating space. These times are then correlated to the reactor conditions using an exponential fit. Simple first order reaction expressions are then used to find the conversion in the reactor. The method uses a two time step kinetic scheme. The first time averaged step is used at the initial times with smaller water concentrations. This gives the average chemical kinetic time as a function of initial overall fuel air ratio, temperature, and pressure. The second instantaneous step is used at higher water concentrations (greater than l x 10(exp -20)) moles per cc) in the mixture which gives the chemical kinetic time as a function of the instantaneous fuel and water mole concentrations, pressure and temperature (T(sub 4)). The simple correlations are then compared to the turbulent mixing times to determine the limiting properties of the reaction. The NASA Glenn GLSENS kinetics code calculates the reaction rates and rate constants for each species in a kinetic scheme for finite kinetic rates. These reaction rates are used to calculate the necessary chemical kinetic times. This time is regressed over the complete initial conditions using the Excel regression routine. Chemical kinetic time equations for H2 and NOx are obtained for H2/Air fuel and for H2/O2. A similar correlation is also developed using data from NASA's Chemical Equilibrium Applications (CEA) code to determine the equilibrium temperature (T(sub 4)) as a function of overall fuel/air ratio, pressure and initial temperature (T(sub 3)). High values of the regression coefficient R squared are obtained.

  4. Assessment of organic compound exposures, thermal comfort parameters, and HVAC system-driven air exchange rates in public school portable classrooms in California

    SciTech Connect

    Shendell, Derek Garth

    2003-01-01

    The prevalence of prefabricated, portable classrooms (portables, relocatables, RCs) has increased due to class size reduction initiatives and limited resources. Classroom mechanical wall-mount heating, ventilation, and air conditioning (HVAC) systems may function improperly or not be maintained; lower ventilation rates may impact indoor air and environmental quality (IEQ). Materials in portables may off-gas volatile organic compounds (VOCs), including formaldehyde, as a function of age, temperature, and humidity. For a pilot study, public K-12 schools located in or serving target areas within five Los Angeles County communities were identified. In two communities where school districts (SD) consented, 1-3 randomly selected portables, one newer and one older, and one main building control classroom from each participating school were included. Sampling was conducted over a five-day school week in the cooling and heating seasons, or repeated twice in the cooling season. Measurements included passive samplers for VOCs, formaldehyde and acetaldehyde, and air exchange rate (AER) calculation; indoor air temperature and humidity; technician walk-through surveys; an interview questionnaire above HVAC system operation and maintenance (O and M). For an intervention study evaluating advanced HVAC technologies in comparison to the common conventional technology, and materials for source reduction of VOCs, four RC were manufactured and located in pairs at two schools in two recruited Northern California SD in different climate zones. RCs were built with the two HVAC systems, cabinetry and conduit for monitoring equipment, and standard or advanced interior finish materials. Each RC was its own control in a case-crossover design--HVAC systems alternately operated for 1-2 week intervals in the 2001-02 school year, with IEQ monitoring including aldehyde and indoor air temperature and humidity data. Measured classroom AER were low, formaldehyde concentrations were below the state

  5. Raman measurement of mixing and finite-rate chemistry in a supersonic hydrogen-air diffusion flame

    SciTech Connect

    Cheng, T.S.; Wehrmeyer, J.A.; Pitz, R.W. . Dept. of Mechanical Engineering); Jarrett, O. Jr.; Northam, G.B. . Langley Research Center)

    1994-10-01

    Ultraviolet (UV) spontaneous vibrational Raman scattering and laser-induced predissociative fluorescence (LIPF) from a KrF excimer laser are combined to simultaneously measure temperature, major species concentrations (H[sub 2], O[sub 2], N[sub 2], H[sub 2]O), and OH radical concentration in a supersonic lifted co-flowing hydrogen-air diffusion flame. The axisymmetric flame is formed when a sonic jet of hydrogen mixes with a Mach 2 annular jet of vitiated air. Mean and rms profiles of temperature, species concentrations, and mixture fraction are obtained throughout the supersonic flame. Simultaneous measurements of the chemical species and temperature are compared with frozen chemistry and equilibrium chemistry limits to assess the local state of the mixing and chemistry. Upstream of the lifted flame base, a very small amount of reaction occurs form mixing with hot vitiated air. Downstream of the lifted flame base, strong turbulent mixing leads to sub equilibrium values of temperature and OH concentration. Due to the interaction of velocity and temperature in supersonic compressible flames, the fluctuations of temperature and species concentrations are found to be higher than subsonic flames. Farther downstream, slow three-body recombination reactions result in super equilibrium OH concentrations that depress temperatures below their equilibrium values.

  6. The influence of a low air pressure environment on human metabolic rate during short-term (< 2 h) exposures.

    PubMed

    Cui, W; Wang, H; Wu, T; Ouyang, Q; Hu, S; Zhu, Y

    2017-03-01

    Passengers in aircraft cabins are exposed to low-pressure environments. One of the missing links in the research on thermal comfort under cabin conditions is the influence of low air pressure on the metabolic rate. In this research, we simulated the cabin pressure regime in a chamber in which the pressure level could be controlled. Three pressure levels (101/85/70 kPa) were tested to investigate how metabolic rate changed at different pressure levels. The results show that as pressure decreased, the respiratory flow rate (RFR) at standard condition (STPD: 0°C, 101 kPa) significantly decreased. Yet the oxygen (O2 ) consumption and carbon dioxide (CO2 ) production significantly increased, as reflected in the larger concentration difference between inhaled and exhaled air. A significant increase in the respiratory quotient (RQ) was also observed. For metabolic rate, no significant increase (P > 0.05) was detected when pressure decreased from 101 kPa to 85 kPa; however, the increase associated with a pressure decrease from 85 kPa to 70kPa was significant (P < 0.05). Empirical equations describing the above parameters are provided, which can be helpful for thermal comfort assessment in short-haul flights.

  7. A review of reaction rates and thermodynamic and transport properties for an 11-species air model for chemical and thermal nonequilibrium calculations to 30000 K

    NASA Technical Reports Server (NTRS)

    Gupta, Roop N.; Yos, Jerrold M.; Thompson, Richard A.; Lee, Kam-Pui

    1990-01-01

    Reaction rate coefficients and thermodynamic and transport properties are reviewed and supplemented for the 11-species air model which can be used for analyzing flows in chemical and thermal nonequilibrium up to temperatures of 3000 K. Such flows will likely occur around currently planned and future hypersonic vehicles. Guidelines for determining the state of the surrounding environment are provided. Curve fits are given for the various species properties for their efficient computation in flowfield codes. Approximate and more exact formulas are provided for computing the properties of partially ionized air mixtures in a high energy environment. Limitations of the approximate mixing laws are discussed for a mixture of ionized species. An electron number-density correction for the transport properties of the charged species is obtained. This correction has been generally ignored in the literature.

  8. A comparative study of terrestrial gamma dose rate in air measured by thermoluminescent dosimeter, portable survey meter and HPGe gamma spectrometer.

    PubMed

    Huang, Yan-Jun; Guo, Gui-Yin; He, Yi; Yang, Li-Tao; Shan, Zhen; Chen, Chao-Feng; Shang-Guan, Zhi-Hong

    2016-11-01

    In this paper, three different widely-used measurement techniques for environmental gamma dose rate were studied and compared, i.e., the thermoluminescent dosimeter, the portable survey meter and the spectrometric analysis. Thirteen investigation sites were selected, and the TLDs were arranged to accumulate the radiation signals during an interval of about one quarter, the instant dose rates by using a portable survey meter were collected around the site, and top surface soils were sampled in the surroundings for radionuclides analyzing in laboratory. The results from these methods were compared, which revealed high correlations. The differences and possible uncertainties for the three methods were analyzed, inspired a further study should be conducted to have more successful estimation of dose rate in surface air.

  9. Adapting Biofilter Processes to Treat Spray Painting Exhausts: Concentration and Leveling of Vapor Delivery Rates, and Enhancement of Destruction by Exhaust Recirculation

    DTIC Science & Technology

    2001-12-20

    biological air treatment system is biofiltration. Biofiltration is a process that utilizes microorganisms immobilized in the form of a biofilm layer on...1991; Devinny et al., 1999). Biofiltration is a process that utilizes microorganisms immobilized in the form of a biofilm layer on an organic... model for the removal of dichloromethane from waste gases using a biological trickling filter (Part I)," Bioprocess Engr. 6:93–99. Diks, R.M.M. and

  10. Detailed Distribution Map of Absorbed Dose Rate in Air in Tokatsu Area of Chiba Prefecture, Japan, Constructed by Car-Borne Survey 4 Years after the Fukushima Daiichi Nuclear Power Plant Accident.

    PubMed

    Inoue, Kazumasa; Arai, Moeko; Fujisawa, Makoto; Saito, Kyouko; Fukushi, Masahiro

    2017-01-01

    A car-borne survey was carried out in the northwestern, or Tokatsu, area of Chiba Prefecture, Japan, to make a detailed distribution map of absorbed dose rate in air four years after the Fukushima Daiichi Nuclear Power Plant accident. This area was chosen because it was the most heavily radionuclide contaminated part of Chiba Prefecture and it neighbors metropolitan Tokyo. Measurements were performed using a 3-in × 3-in NaI(Tl) scintillation spectrometer in June 2015. The survey route covered the whole Tokatsu area which includes six cities. A heterogeneous distribution of absorbed dose rate in air was observed on the dose distribution map. Especially, higher absorbed dose rates in air exceeding 80 nGy h-1 were observed along national roads constructed using high porosity asphalt, whereas lower absorbed dose rates in air were observed along local roads constructed using low porosity asphalt. The difference between these asphalt types resulted in a heterogeneous dose distribution in the Tokatsu area. The mean of the contribution ratio of artificial radionuclides to absorbed dose rate in air measured 4 years after the accident was 29% (9-50%) in the Tokatsu area. The maximum absorbed dose rate in air, 201 nGy h-1 was observed at Kashiwa City. Radiocesium was deposited in the upper 1 cm surface layer of the high porosity asphalt which was collected in Kashiwa City and the environmental half-life of the absorbed dose rate in air was estimated to be 1.7 years.

  11. 3D image-based adapted high-dose-rate brachytherapy in cervical cancer with and without interstitial needles: measurement of applicator shift between imaging and dose delivery

    PubMed Central

    Thunberg, Per; With, Anders; Mordhorst, Louise Bohr; Persliden, Jan

    2017-01-01

    Purpose Using 3D image-guided adaptive brachytherapy for cervical cancer treatment, it often means that patients are transported and moved during the treatment procedure. The purpose of this study was to determine the intra-fractional longitudinal applicator shift in relation to the high risk clinical target volume (HR-CTV) by comparing geometries at imaging and dose delivery for patients with and without needles. Material and methods Measurements were performed in 33 patients (71 fractions), where 25 fractions were without and 46 were with interstitial needles. Gold markers were placed in the lower part of the cervix as a surrogate for HR-CTV, enabling distance measurements between HR-CTV and the ring applicator. Shifts of the applicator relative to the markers were determined using planning computed tomography (CT) images used for planning, and the radiographs obtained at dose delivery. Differences in the physical D90 for HR-CTV due to applicator shifts were simulated individually in the treatment planning system to provide the relative dose variation. Results The maximum distances of the applicator shifts, in relation to the markers, were 3.6 mm (caudal), and –2.5 mm (cranial). There was a significant displacement of –0.7 mm (SD = 0.9 mm) without needles, while with needles there was no significant shift. The relative dose variation showed a significant increase in D90 HR-CTV of 1.6% (SD = 2.6%) when not using needles, and no significant dose variation was found when using needles. Conclusions The results from this study showed that there was a small longitudinal displacement of the ring applicator and a significant difference in displacement between using interstitial needles or not. PMID:28344604

  12. Influence of photon energy spectra from brachytherapy sources on Monte Carlo simulations of kerma and dose rates in water and air

    SciTech Connect

    Rivard, Mark J.; Granero, Domingo; Perez-Calatayud, Jose; Ballester, Facundo

    2010-02-15

    Purpose: For a given radionuclide, there are several photon spectrum choices available to dosimetry investigators for simulating the radiation emissions from brachytherapy sources. This study examines the dosimetric influence of selecting the spectra for {sup 192}Ir, {sup 125}I, and {sup 103}Pd on the final estimations of kerma and dose. Methods: For {sup 192}Ir, {sup 125}I, and {sup 103}Pd, the authors considered from two to five published spectra. Spherical sources approximating common brachytherapy sources were assessed. Kerma and dose results from GEANT4, MCNP5, and PENELOPE-2008 were compared for water and air. The dosimetric influence of {sup 192}Ir, {sup 125}I, and {sup 103}Pd spectral choice was determined. Results: For the spectra considered, there were no statistically significant differences between kerma or dose results based on Monte Carlo code choice when using the same spectrum. Water-kerma differences of about 2%, 2%, and 0.7% were observed due to spectrum choice for {sup 192}Ir, {sup 125}I, and {sup 103}Pd, respectively (independent of radial distance), when accounting for photon yield per Bq. Similar differences were observed for air-kerma rate. However, their ratio (as used in the dose-rate constant) did not significantly change when the various photon spectra were selected because the differences compensated each other when dividing dose rate by air-kerma strength. Conclusions: Given the standardization of radionuclide data available from the National Nuclear Data Center (NNDC) and the rigorous infrastructure for performing and maintaining the data set evaluations, NNDC spectra are suggested for brachytherapy simulations in medical physics applications.

  13. Peak Expiratory Flow, Breath Rate and Blood Pressure in Adults with Changes in Particulate Matter Air Pollution during the Beijing Olympics: A Panel Study

    PubMed Central

    Mu, Lina; Deng, Furong; Tian, Lili; Li, Yanli; Swanson, Mya; Ying, Jingjing; Browne, Richard W; Rittenhouse-Olson, Kate; Zhang, Junfeng (Jim); Zhang, Zuo-Feng; Bonner, Matthew R.

    2014-01-01

    Objectives This study aims to examine whether changes in short-term exposures to particulate matter are associated with changes in lung function, breath rate, and blood pressure among healthy adults and whether smoking status modifies the association. Methods We took advantage of the artificially controlled changes in air pollution levels that occurred during the 2008 Olympic Games in Beijing, China and conducted a panel study of 201 Beijing residents. Data were collected before, during, and after the Olympics, respectively. Linear mixed-effects models and generalized estimating equation models were used to compare measurements of peak expiratory flow, breath rate, blood pressure across the three time points. Results The mean values of peak expiratory flow were 346.0 L/min, 399.3 L/min, and 364.1 L/min over the three study periods. Peak expiratory flow levels increased in 78% of the participants when comparing the during- and pre- Olympics time points, while peak expiratory flow levels decreased in 80% of participants for the post- and during-Olympic periods comparison. In subgroup analyses comparing the during -Olympic to pre-Olympic time points, we found a larger percentage change in peak expiratory flow (+17%) among female, younger and non-smoking participants than among male, elderly and smoking participants (+12%). The percentage of participants with a fast breath rate (>20/min) changed from 9.7%, to 4.9%, to 30.1% among females, and from 7.9%, to 2.6%, to 27.3% among males over the three time points respectively. The changes on blood pressure over the three study periods were not very clear, although there is an increase in diastolic pressure and a decrease in pulse pressure among males during the games. Conclusions The results suggest that exposure to different air pollution levels has significant effects on respiratory function. Smoking, age and gender appear to modify participants’ biological response to changes in air quality. PMID:24906062

  14. Maintaining perioperative normothermia in the patient undergoing cesarean delivery.

    PubMed

    Carpenter, Lavenia; Baysinger, Curtis L

    2012-07-01

    Anesthesia and surgery interfere with normal thermoregulation, and nearly all patients will become hypothermic unless compensatory measures are used. Preoperative patient warming and intraoperative methods using forced air and warmed intravenous fluids are important methods for maintaining patient's core temperature during the perioperative period. The benefits of maintaining normothermia include reductions in postoperative wound infection, the risk of perioperative coagulopathy, and myocardial ischemia. These advantages, demonstrated in patients undergoing general surgery, would be expected in patients undergoing gynecological surgery but have not been specifically studied in that population. Few studies have examined the maternal and neonatal effects of hypothermia after cesarean delivery. The results conflict as to the effectiveness of maternal warming techniques used to prevent it and the effects on neonatal temperature and acid-base status at delivery. Large prospective studies will be required to show significant effects on rates of maternal wound infection after cesarean delivery. European and American national obstetrical organizations have not published recommendations regarding the perioperative thermal regulation for cesarean delivery. We review the physiology of thermal regulation and perioperative thermal management in surgical patients and the literature that has examined perioperative maternal warming for cesarean delivery.

  15. High rates of serum Se deficiency among HIV and HCV infected and uninfected drug users in Buenos Aires, Argentina

    PubMed Central

    Sheehan, Heidi B; Benetucci, Jorge; Muzzio, Estela; Redini, Liliana; Naveira, Jorge; Segura, Marcela; Weissenbacher, Mercedes; Tang, Alice M

    2012-01-01

    Objective To describe the prevalence and correlates of low serum Se and determine whether HIV, hepatitis C virus (HCV) and/or types of drugs used are associated with serum Se in a cohort of infected and uninfected drug users. Design Independent correlates of low serum Se levels based on data collected from food recalls, physical exams, and clinical status questionnaires were identified using multivariate analysis. Setting Buenos Aires, Argentina Subjects A total of 205 (25 females and 180 males) former and current drug users Results Drug users had an average serum Se level of 69.8±32.8 μg/dl, and 82% were considered deficient (< 85μg/l). Multivariate analyses found that HIV and/or HCV infection had lower mean Se compared to healthy, uninfected drug users (HIV/HCV co-infection: −25.3 μg/l (SE =7.6, p=0.001); HIV alone: −28.9 μg/l (SE=6.9, p<0.001); HCV alone −19.4 μg/l (SE = 7.1, p=0.006). Current and previous drug use was associated with higher serum Se. Cigarette smoking and heavy alcohol consumption were not found to be associated with Se status. Conclusions Low serum Se levels are highly prevalent among drug users in Buenos Aires, Argentina. Se supplementation and/or dietary interventions may be warranted in drug users who are at high risk of HIV and/or HCV infection. PMID:21740621

  16. The relationship between oxygen consumption rate and viability of in vivo-derived pig embryos vitrified by the micro volume air cooling method.

    PubMed

    Sakagami, N; Nishida, K; Misumi, K; Hirayama, Y; Yamashita, S; Hoshi, H; Misawa, H; Akiyama, K; Suzuki, C; Yoshioka, K

    2016-01-01

    The aim of this study was to assess the viability of vitrified-warmed in vivo-derived pig embryos after measuring the oxygen consumption rate. Six days after artificial insemination, blastocysts were collected from gilts and vitrified by the micro volume air cooling method. The oxygen consumption rate was measured in 60 vitrified-warmed embryos, which were then cultured for 48h to assess the viability. The survival (re-expansion) rate of embryos after warming was 85.0%. The average oxygen consumption rate of embryos immediately after warming was greater in embryos which could re-expand during subsequent culture (F=0.75±0.04) than that in those which failed to re-expand (F=0.33±0.05). Moreover, the oxygen consumption rate of vitrified-warmed embryos was greater in the hatched (F=0.88±0.06) than that in the not-hatched group (F=0.53±0.04). When the oxygen consumption rate of the vitrified-warmed embryos and the numbers of viable and dead cells in embryos were determined, there was a positive correlation between the oxygen consumption rate and the number of live cells (P<0.01, r=0.538). A total of 29 vitrified embryos after warming and measuring the oxygen consumption rate were surgically transferred into uterine horns of two recipients. Both of the recipients become pregnant and farrowed 12 healthy piglets. These results demonstrate that the oxygen consumption rate of vitrified-warmed pig embryos can be related to the number of live cells and that the measurement of oxygen consumption of embryos after cryopreservation may be useful for estimating embryo survivability.

  17. Accumulation rates during 1311-2011 CE in North Central Greenland derived from air-borne radar data

    NASA Astrophysics Data System (ADS)

    Karlsson, Nanna; Eisen, Olaf; Dahl-Jensen, Dorthe; Freitag, Johannes; Kipfstuhl, Sepp; Lewis, Cameron; Nielsen, Lisbeth; Paden, John; Winter, Anna; Wilhelms, Frank

    2016-11-01

    Radar-detected internal layering contains information on past accumulation rates and patterns. In this study, we assume that the radar layers are isochrones, and use the layer stratigraphy in combination with ice-core measurements and numerical methods to retrieve accumulation information for the northern part of central Greenland. Measurements of the dielectric properties of an ice core from the NEEM (North Greenland Eemian Ice Drilling) site, allow for correlation of the radar layers with volcanic horizons to obtain an accurate age of the layers. We obtain accumulation patterns averaged over 100 a for the period 1311-2011. Our results show a clear trend of high accumulation rates west of the ice divide and low accumulation rates east of the ice divide. At the NEEM site the accumulation pattern is persistent during our study period and only small temporal variations occur in the accumulation rate. However, from approximately 200 km south of the NEEM drill site, the accumulation rate shows temporal variations based on our centennial averages. We attribute this variation to shifts in the location of the high-low accumulation boundary that usually is aligned with the ice divide, but appears to have moved across the divide in the past.

  18. Technology Solutions Case Study: Air-To-Water Heat Pumps with Radiant Delivery in Low Load Homes, Tucson, Arizona and Chico, California

    SciTech Connect

    2013-11-01

    Space conditioning represents nearly 50% of average residential household energy consumption, highlighting the need to identify alternative cost-effective, energy-efficient cooling and heating strategies. As homes are better built, there is an increasing need for strategies that are particularly well suited for high performance, low load homes. ARBI researchers worked with two test homes in hot-dry climates to evaluate the in-situ performance of air-to-water heat pump (AWHP) systems, an energy efficient space conditioning solution designed to cost-effectively provide comfort in homes with efficient, safe, and durable operation. Both systems were fully instrumented and have been monitored over one year to capture complete performance data over the cooling and heating seasons. Results are used to quantify energy savings, cost-effectiveness, and system performance using different operating modes and strategies. This strategy is most effective in tight, insulated homes with high levels of thermal mass (i.e. exposed slab floors).

  19. Encapsulation of proteins in hydrogel carrier systems for controlled drug delivery: influence of network structure and drug size on release rate.

    PubMed

    Bertz, Andreas; Wöhl-Bruhn, Stefanie; Miethe, Sebastian; Tiersch, Brigitte; Koetz, Joachim; Hust, Michael; Bunjes, Heike; Menzel, Henning

    2013-01-20

    Novel hydrogels based on hydroxyethyl starch modified with polyethylene glycol methacrylate (HES-P(EG)₆MA) were developed as delivery system for the controlled release of proteins. Since the drug release behavior is supposed to be related to the pore structure of the hydrogel network the pore sizes were determined by cryo-SEM, which is a mild technique for imaging on a nanometer scale. The results showed a decreasing pore size and an increase in pore homogeneity with increasing polymer concentration. Furthermore, the mesh sizes of the hydrogels were calculated based on swelling data. Pore and mesh size were significantly different which indicates that both structures are present in the hydrogel. The resulting structural model was correlated with release data for bulk hydrogel cylinders loaded with FITC-dextran and hydrogel microspheres loaded with FITC-IgG and FITC-dextran of different molecular size. The initial release depended much on the relation between hydrodynamic diameter and pore size while the long term release of the incorporated substances was predominantly controlled by degradation of the network of the much smaller meshes.

  20. Internal short circuit and accelerated rate calorimetry tests of lithium-ion cells: Considerations for methane-air intrinsic safety and explosion proof/flameproof protection methods

    PubMed Central

    Dubaniewicz, Thomas H.; DuCarme, Joseph P.

    2016-01-01

    Researchers with the National Institute for Occupational Safety and Health (NIOSH) studied the potential for lithium-ion cell thermal runaway from an internal short circuit in equipment for use in underground coal mines. In this third phase of the study, researchers compared plastic wedge crush-induced internal short circuit tests of selected lithium-ion cells within methane (CH4)-air mixtures with accelerated rate calorimetry tests of similar cells. Plastic wedge crush test results with metal oxide lithium-ion cells extracted from intrinsically safe evaluated equipment were mixed, with one cell model igniting the chamber atmosphere while another cell model did not. The two cells models exhibited different internal short circuit behaviors. A lithium iron phosphate (LiFePO4) cell model was tolerant to crush-induced internal short circuits within CH4-air, tested under manufacturer recommended charging conditions. Accelerating rate calorimetry tests with similar cells within a nitrogen purged 353-mL chamber produced ignitions that exceeded explosion proof and flameproof enclosure minimum internal pressure design criteria. Ignition pressures within a 20-L chamber with 6.5% CH4-air were relatively low, with much larger head space volume and less adiabatic test conditions. The literature indicates that sizeable lithium thionyl chloride (LiSOCl2) primary (non rechargeable) cell ignitions can be especially violent and toxic. Because ignition of an explosive atmosphere is expected within explosion proof or flameproof enclosures, there is a need to consider the potential for an internal explosive atmosphere ignition in combination with a lithium or lithium-ion battery thermal runaway process, and the resulting effects on the enclosure. PMID:27695201

  1. Internal short circuit and accelerated rate calorimetry tests of lithium-ion cells: Considerations for methane-air intrinsic safety and explosion proof/flameproof protection methods.

    PubMed

    Dubaniewicz, Thomas H; DuCarme, Joseph P

    2016-09-01

    Researchers with the National Institute for Occupational Safety and Health (NIOSH) studied the potential for lithium-ion cell thermal runaway from an internal short circuit in equipment for use in underground coal mines. In this third phase of the study, researchers compared plastic wedge crush-induced internal short circuit tests of selected lithium-ion cells within methane (CH4)-air mixtures with accelerated rate calorimetry tests of similar cells. Plastic wedge crush test results with metal oxide lithium-ion cells extracted from intrinsically safe evaluated equipment were mixed, with one cell model igniting the chamber atmosphere while another cell model did not. The two cells models exhibited different internal short circuit behaviors. A lithium iron phosphate (LiFePO4) cell model was tolerant to crush-induced internal short circuits within CH4-air, tested under manufacturer recommended charging conditions. Accelerating rate calorimetry tests with similar cells within a nitrogen purged 353-mL chamber produced ignitions that exceeded explosion proof and flameproof enclosure minimum internal pressure design criteria. Ignition pressures within a 20-L chamber with 6.5% CH4-air were relatively low, with much larger head space volume and less adiabatic test conditions. The literature indicates that sizeable lithium thionyl chloride (LiSOCl2) primary (non rechargeable) cell ignitions can be especially violent and toxic. Because ignition of an explosive atmosphere is expected within explosion proof or flameproof enclosures, there is a need to consider the potential for an internal explosive atmosphere ignition in combination with a lithium or lithium-ion battery thermal runaway process, and the resulting effects on the enclosure.

  2. Protein quantity on the air-solid interface determines degradation rates of human growth hormone in lyophilized samples.

    PubMed

    Xu, Yemin; Grobelny, Pawel; Von Allmen, Alexander; Knudson, Korben; Pikal, Michael; Carpenter, John F; Randolph, Theodore W

    2014-05-01

    Recombinant human growth hormone (rhGH) was lyophilized with various glass-forming stabilizers, employing cycles that incorporated various freezing and annealing procedures to manipulate glass formation kinetics, associated relaxation processes, and glass-specific surface areas (SSAs). The secondary structure in the cake was monitored by infrared and in reconstituted samples by circular dichroism. The rhGH concentrations on the surface of lyophilized powders were determined from electron spectroscopy for chemical analysis. Glass transition temperature (Tg ), SSAs, and water contents were determined immediately after lyophilization. Lyophilized samples were incubated at 323 K for 16 weeks, and the resulting extents of rhGH aggregation, oxidation, and deamidation were determined after rehydration. Water contents and Tg were independent of lyophilization process parameters. Compared with samples lyophilized after rapid freezing, rhGH in samples that had been annealed in frozen solids prior to drying, or annealed in glassy solids after secondary drying retained more native-like protein secondary structure, had a smaller fraction of the protein on the surface of the cake, and exhibited lower levels of degradation during incubation. A simple kinetic model suggested that the differences in the extent of rhGH degradation during storage in the dried state between different formulations and processing methods could largely be ascribed to the associated levels of rhGH at the solid-air interface after lyophilization.

  3. Evaluation of the reaction rate constants for the gas-phase Al-CH4-air combustion chemistry

    NASA Astrophysics Data System (ADS)

    Sharipov, A. S.; Titova, N. S.; Starik, A. M.

    2012-10-01

    The most likely reaction pathways and reaction products in the Al-CH4-O2-N2 system are investigated using density functional theory and ab initio calculations. The B3LYP functional with extended 6-311+G(3df,2p) basis set as well as the CBS-QB3 composite method are mainly utilised. Theoretical analysis of corresponding reaction rate constants is also performed with the use of simple theoretical models. A critical overview of current knowledge on combustion-relevant reactions with aluminium compounds is given. On the basis of critical comparison of available experimental kinetic data with theoretical calculations, the approximations for rate constants for 44 reversible elementary reactions involving Al-containing species are recommended for use in combustion issues.

  4. Short communication: Effects of dairy calf hutch elevation on heat reduction, carbon dioxide concentration, air circulation, and respiratory rates.

    PubMed

    Moore, D A; Duprau, J L; Wenz, J R

    2012-07-01

    Heat stress affects dairy calf welfare and can result in morbidity, mortality, and lower weight gain. The purpose of this project was to evaluate the effects of elevating the back of plastic calf hutches on measures of ventilation and heat stress. A total of 15 calves housed in individual hutches were enrolled, with each calf hutch serving as its own control. Heat, humidity, carbon dioxide, and wind speed were measured inside each hutch and the observations were compared with external measurements over two 24-h periods; 1 period without and 1 with hutch elevation. Respiratory rates were measured in the morning and afternoon as an indicator of the degree of heat stress experienced by calves with and without elevation of the hutch. When the hutch was elevated, internal hutch temperatures were cooler than external temperatures, hutch carbon dioxide levels were lower and respiratory rates were lower, particularly comparing the afternoon observation periods.

  5. Delivery Innovations.

    PubMed

    2017-03-01

    The need for innovations in care delivery is recognized by providers, payers, and patients alike. Hospitals, physicians, and other clinicians are experimenting with new models of care designed to better meet patients' needs, reduce administrative burdens, and lower costs. The Affordable Care Act placed the Medicare and Medicaid programs at the center of a national effort to experiment with delivery and payment models designed to improve care and contain costs. These public-sector efforts have often aligned with private initiatives, such as the use of reference pricing-in which an insurer will only pay for a service at the price available from the lowest-cost provider. Employers in the public and private sectors have adopted value-based insurance design, in which copayments and deductibles are calibrated to the clinical benefit obtained from different services. Patients have the most to gain-or lose-from delivery innovations. Better, more efficient care should translate into better health and lower costs, but payment models designed to encourage innovation may have the unintended effect of limiting access to care.

  6. Dry powders based on PLGA nanoparticles for pulmonary delivery of antibiotics: modulation of encapsulation efficiency, release rate and lung deposition pattern by hydrophilic polymers.

    PubMed

    Ungaro, Francesca; d'Angelo, Ivana; Coletta, Ciro; d'Emmanuele di Villa Bianca, Roberta; Sorrentino, Raffaella; Perfetto, Brunella; Tufano, Maria Antonietta; Miro, Agnese; La Rotonda, Maria Immacolata; Quaglia, Fabiana

    2012-01-10

    Although few experimental studies have been handled so far to exploit the potential of poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) in the production of dry powders for antibiotic inhalation, there has been no comprehensive study on the role played by NP composition. In this work, we try to shed light on this aspect by designing and developing a pulmonary delivery system for antibiotics, such as tobramycin (Tb), based on PLGA NPs embedded in an inert microcarrier made of lactose, referred to as nano-embedded micro-particles (NEM). At nanosize level, helper hydrophilic polymers were used to impart the desired surface, bulk and release properties to PLGA NPs prepared by a modified emulsion-solvent diffusion technique. Results showed that poly(vinyl alcohol) (PVA) and chitosan (CS) are essential to optimise the size and modulate the surface properties of Tb-loaded PLGA NPs, whereas the use of alginate (Alg) allows efficient Tb entrapment within NPs and its release up to one month. Optimized formulations display good in vitro antimicrobial activity against P. aeruginosa planktonic cells. Furthermore, spray-drying of the NPs with lactose yielded NEM with peculiar but promising flow and aerosolization properties, while preserving the peculiar NP features. Nonetheless, in vivo biodistribution studies showed that PVA-modified Alg/PLGA NPs reached the deep lung, while CS-modified NPs were found in great amounts in the upper airways, lining lung epithelial surfaces. In conclusion, PLGA NP composition appears to play a crucial role in determining not only the technological features of NPs but, once processed in the form of NEM, also their in vitro/in vivo deposition pattern.

  7. Sensor for Individual Burner Control of Coal Firing Rate, Fuel-Air Ratio and Coal Fineness Correlation

    SciTech Connect

    Wayne Hill; Roger Demler

    2004-06-01

    The project's overall objective is to develop a commercially viable dynamic signature based sensing system that is used to infer the flow rate and fineness of pulverized coal. This eighteen month effort will focus on developments required to transfer the measurement system from the laboratory to a field ready prototype system. This objective will be achieved through the completion of the laboratory development of the sensor and data algorithm followed by full scale field tests of a portable measurement system. The sensing system utilizes accelerometers attached externally to coal feeder pipes. Raw data is collected from the impingement of the coal particles as well as the acoustic noise generated from the flow and is transformed into characteristic signatures through proper calibration that are meaningful to the operator. The laboratory testing will use a portable version of the sensing system to collect signature data from a variety of flow conditions including coal flow rates, flow orientations, and coal particle characteristics. This work will be conducted at the Coal Flow Measurement Laboratory that is sponsored by EPRI and operated by Airflow Sciences. The data will be used to enhance the algorithm and neural network required to perform real time analysis of the nonspecific signature data. The system will be installed at two full scale power plants to collect data in a real time operating scenario. These short term duration tests will evaluate the ability of the algorithm to accurately infer coal flow rates and determine if the measurement system can be used effectively in an active control loop for combustion diagnostics and burner balancing. At the completion of this project, prototype versions of both a portable system and a permanent installation will be available for final packaging and commercialization by one of the team members. Both types of systems will be marketed for conducting combustion diagnostics and balancing of individual flows to pulverized

  8. SENSOR FOR INDIVIDUAL BURNER CONTROL OF COAL FIRING RATE, FUEL-AIR RATIO AND COAL FINENESS CORRELATION

    SciTech Connect

    Wayne Hill

    2004-02-01

    The project's overall objective is to development a commercially viable dynamic signature based sensing system that is used to infer the flow rate and fineness of pulverized coal. This eighteen month effort will focus on developments required to transfer the measurement system from the laboratory to a field ready prototype system. This objective will be achieved through the completion of the laboratory development of the sensor and data algorithm followed by full scale field tests of a portable measurement system. The sensing system utilizes accelerometers attached externally to coal feeder pipes. Raw data is collected from the impingement of the coal particles as well as the acoustic noise generated from the flow and is transformed into characteristic signatures through proper calibration that are meaningful to the operator. The laboratory testing will use a portable version of the sensing system to collect signature data from a variety of flow conditions including coal flow rates, flow orientations, and coal particle characteristics. This work will be conducted at the Coal Flow Measurement Laboratory that is sponsored by EPRI and operated by Airflow Sciences. The data will be used to enhance the algorithm and neural network required to perform real time analysis of the non-specific signature data. The system will be installed at two full scale power plants to collect data in a real time operating scenario. These short term duration tests will evaluate the ability of the algorithm to accurately infer coal flow rates and determine if the measurement system can be used effectively in an active control loop for combustion diagnostics and burner balancing. At the completion of this project, prototype versions of both a portable system and a permanent installation will be available for final packaging and commercialization by one of the team members. Both types of systems will be marketed for conducting combustion diagnostics and balancing of individual flows to

  9. A practical approach to estimate emission rates of indoor air pollutants due to the use of personal combustible products based on small-chamber studies.

    PubMed

    Szulejko, Jan E; Kim, Ki-Hyun

    2016-02-01

    As emission rates of airborne pollutants are commonly measured from combusting substances placed inside small chambers, those values need to be re-evaluated for the possible significance under practical conditions. Here, a simple numerical procedure is investigated to extrapolate the chamber-based emission rates of formaldehyde that can be released from various combustible sources including e-cigarettes, conventional cigarettes, or scented candles to their concentration levels in a small room with relatively poor ventilation. This simple procedure relies on a mass balance approach by considering the masses of pollutants emitted from source and lost through ventilation under the assumption that mixing occurs instantaneously in the room without chemical reactions or surface sorption. The results of our study provide valuable insights into re-evaluation procedure of chamber data to allow comparison between extrapolated and recommended values to judge the safe use of various combustible products in confined spaces. If two scented candles with a formaldehyde emission rate of 310 µg h(-1) each were lit for 4 h in a small 20 m(3) room with an air change rate of 0.5 h(-1), then the 4-h (candle lit) and 8-h (up to 8 h after candle lighting) TWA [FA] were determined to be 28.5 and 23.5 ppb, respectively. This is clearly above the 8-h NIOSH recommended exposure limit (REL) time weighted average of 16 ppb.

  10. EFFECTS OF COVAPORS ON ADSORPTION RATE COEFFICIENTS OF ORGANIC VAPORS ADSORBED ONTO ACTIVATED CARBON FROM FLOWING AIR

    SciTech Connect

    G. WOOD

    2000-12-01

    Published breakthrough time, adsorption rate, and capacity data for components of organic vapor mixtures adsorbed from flows through fixed activated carbon beds have been analyzed. Capacities (as stoichiometric centers of constant pattern breakthrough curves) yielded stoichiometric times {tau}, which are useful for determining elution orders of mixture components. We also calculated adsorption rate coefficients k{sub v} of the Wheeler (or, more general Reaction Kinetic) breakthrough curve equation, when not reported, from breakthrough times and {tau}. Ninety-five k{sub v} (in mixture)/ k{sub v} (single vapor) ratios at similar vapor concentrations were calculated and averaged for elution order categories. For 43 first-eluting vapors the average ratio (1.07) was statistically no different (0.21 standard deviation) than unity, so that we recommend using the single-vapor k{sub v} for such. Forty-seven second-eluting vapor ratios averaged 0.85 (0.24 standard deviation), also not significantly different from unity; however, other evidence and considerations lead us recommend using k{sub v} (in mixture) = 0.85 k{sub v} (single vapor). Five third- and fourth-eluting vapors gave an average of 0.56 (0.16 standard deviation) for a recommended k{sub v} (in mixture) = 0.56 k{sub v} (single vapor) for such.

  11. Controlled Drug Delivery Using Microdevices

    PubMed Central

    Sanjay, Sharma T.; Dou, Maowei; Fu, Guanglei; Xu, Feng; Li, XiuJun

    2016-01-01

    Therapeutic drugs administered systematically are evenly distributed to the whole body through blood circulation and have to cross many biological barriers before reaching the pathological site. Conventional drug delivery may make drugs inactive or reduce their potency as they may be hydrolyzed or degraded enzymatically and are rapidly excreted through the urinary system resulting in suboptimal concentration of drugs at the desired site. Controlled drug delivery aims to localize the pharmacological activity of the drug to the desired site at desired release rates. The advances made by micro/nanofluidic technologies have provided new opportunities for better-controlled drug delivery. Various components of a drug delivery system can be integrated within a single tiny micro/nanofluidic chip. This article reviews recent advances of controlled drug delivery made by microfluidic/nanofluidic technologies. We first discuss microreservoir-based drug delivery systems. Then we highlight different kinds of microneedles used for controlled drug delivery, followed with a brief discussion about the current limitations and the future prospects of controlled drug delivery systems. PMID:26813304

  12. The Influence of Fuel Moisture, Charge Size, Burning Rate and Air Ventilation Conditions on Emissions of PM, OC, EC, Parent PAHs, and Their Derivatives from Residential Wood Combustion

    PubMed Central

    Shen, Guofeng; Xue, Miao; Wei, Siye; Chen, Yuanchen; Wang, Bin; Wang, Rong; Lv, Yan; Shen, Huizhong; Li, Wei; Zhang, Yanyan; Huang, Ye; Chen, Han; Wei, Wen; Zhao, Qiuyue; Li, Bin; Wu, Haisuo; TAO, Shu

    2014-01-01

    Controlled combustion experiments were conducted to investigate the influence of fuel charge size, moisture, air ventilation and burning rate on the emission factors (EFs) of carbonaceous particulate matter, parent polycyclic aromatic hydrocarbons (pPAHs) and their derivatives from residential wood combustion in a typical brick cooking stove. Measured EFs were found to be independent of fuel charge size, but increased with increasing fuel moisture. Pollution emissions from a normal burning under an adequate air supply condition were the lowest for most pollutants, while more pollutants were emitted when the oxygen deficient atmosphere was formed in stove chamber during fast burning. The impact of these 4 factors on particulate matter size distribution was also studied. Modified combustion efficiency and the four investigated factors explained 68, 72, and 64% of total variations in EFs of PM, organic carbon, and oxygenated PAHs, respectively, but only 36, 38 and 42% of the total variations in EFs of elemental carbon, pPAHs and nitro-PAHs, respectively. PMID:24520723

  13. Effects of particle size and air flow rates on the runaway temperature of bituminous coal at 290K < T < 700K

    SciTech Connect

    Malhotro, V.M.; Crelling, J.C.

    1987-01-01

    Spontaneous ignition and combustion of coal are major problems not only for actual mining of coal but also for its transportation and for industrial users. Most coals are prone to spontaneous combustion, but their susceptibility to ignition increases as the coal rank decreases. However, there are many anomalies to this straight rank order susceptibility. Chamberlain and Hall have in fact, pointed out that some higher rank coals may be more susceptible to spontaneous ignition than lower rank coals. The causes and mechanisms of spontaneous ignition are enigmatic because exceptions exist for every previously-suggested, single cause. Several models have been advanced to describe spontaneous heating, however. Among these are coal rank, electrostatic effects, geological factors, temperature, microbial ignition, the reduction in reactivity due to deterioration, air flow rates, particle size, pyrite content, porosity and water wetting of coal. The purpose of this research was to examine the factors which may contribute to spontaneous ignition of ultrafine (particle size < 250 /mu/m) bituminous coals and maceral enriched fractions under storage, air flow and/or dense phase pneumatic conditions and to understand physical interactions and chemical reactions pathways which may lead to spontaneous ignition of bituminous coals. We have initiated spontaneous ignition, FTIR, DSC, TGA and EPR measurements to accumulate data which can be used to propose mathematical models for spontaneous ignition of stored and pneumatically conveyed coals. In this report, we present our preliminary results on a high-volatile bituminous coal subjected to ignition temperature and FTIR measurements.

  14. Modelling the contribution of individual radionuclides to the total gamma air kerma rate for the sediments of the Ribble Estuary, NW England.

    PubMed

    Brown, J E; McDonald, P; Williams, M; Parker, A; Rae, J E

    1999-12-01

    The aim of this study was to test the performance of a published dose-rate model, investigate the contribution of individual radionuclides to the total gamma air kerma rate (GAKR) and derive external doses to man in the Ribble Estuary, NW England. GAKRs were measured and sediment cores were collected in order to determine radionuclide specific activities with depth. The latter values were used as input data for the external dose-rate model. The model has a slight tendency to over-predict the GAKR, but, on average, the model predictions fall within +/-26% of the measured value. Improvements, in the present case, might be made by accounting for core shortening and variations in soil density in the input data. The model predicted that, for exposed intertidal mud sites, a range of GAKRs between 0.011 and 0.022 microGy h(-1) was attributable to Springfields discharges alone. The contribution due to 234mPa and 234Th ranged between 20 and 60%. An excess GAKR (GAKR arising from anthropogenic emissions alone) of 0.139-0.150 microGy h(-1), used in conjunction with relevant habit-survey data (for a potential critical group) and conversion factors, yielded a dose to man of 0.029-0.031 mSv year(-1).

  15. Rate acceleration of the heterogeneous reaction of ozone with a model alkene at the air-ice interface at low temperatures.

    PubMed

    Ray, Debajyoti; Malongwe, Joseph K'Ekuboni; Klán, Petr

    2013-07-02

    The kinetics of the ozonation reaction of 1,1-diphenylethylene (DPE) on the surface of ice grains (also called "artificial snow"), produced by shock-freezing of DPE aqueous solutions or DPE vapor-deposition on pure ice grains, was studied in the temperature range of 268 to 188 K. A remarkable and unexpected increase in the apparent ozonation rates with decreasing temperature was evaluated using the Langmuir-Hinshelwood and Eley-Rideal kinetic models, and by estimating the apparent specific surface area of the ice grains. We suggest that an increase of the number of surface reactive sites, and possibly higher ozone uptake coefficients are responsible for the apparent rate acceleration of DPE ozonation at the air-ice interface at lower temperatures. The increasing number of reactive sites is probably related to the fact that organic molecules are displaced more to the top of a disordered interface (or quasi-liquid) layer on the ice surface, which makes them more accessible to the gas-phase reactants. The effect of NaCl as a cocontaminant on ozonation rates was also investigated. The environmental implications of this phenomenon for natural ice/snow are discussed. DPE was selected as an example of environmentally relevant species which can react with ozone. For typical atmospheric ozone concentrations in polar areas (20 ppbv), we estimated that its half-life on the ice surface would decrease from ∼5 days at 258 K to ∼13 h at 188 K at submonolayer DPE loadings.

  16. Experimental study on copper cathode erosion rate and rotational velocity of magnetically driven arcs in a well-type cathode non-transferred plasma torch operating in air

    NASA Astrophysics Data System (ADS)

    Chau, S. W.; Hsu, K. L.; Lin, D. L.; Tzeng, C. C.

    2007-04-01

    The cathode erosion rate, arc root velocity and output power of a well-type cathode (WTC), non-transferred plasma torch operating in air are studied experimentally in this paper. An external solenoid to generate a magnetically driven arc and a circular swirler to produce a vortex flow structure are equipped in the studied torch system, which is designed to reduce the erosion rate at the cathode. A least square technique is applied to correlate the system parameters, i.e. current, axial magnetic field and mass flow rate, with the cathode erosion rate, arc root velocity and system power output. In the studied WTC torch system, the cathode erosion has a major thermal erosion component and a minor component due to the ion-bombardment effect. The cathode erosion increases with the increase of current due to the enhancement in both Joule heating and ion bombardment. The axial magnetic field can significantly reduce the cathode erosion by reducing the thermal loading of cathode materials at the arc root and improving the heat transfer to gas near the cathode. But, the rise in the mass flow rate leads to the deterioration of erosion, since the ion-bombardment effect prevails over the convective cooling at the cathode. The most dominant system parameter to influence the arc root velocity is the axial magnetic field, which is mainly contributed to the magnetic force driving the arc. The growth in current has a negative impact on increasing the arc root velocity, because the friction force acting at the spot due to a severe molten condition becomes the dominant component counteracting the magnetic force. The mass flow rate also suppresses the arc root velocity, as a result of which the arc root moves in the direction against that of the swirled working gas. All system parameters such as current, magnetic field and gas flow rate increase with the increase in the torch output power. The experimental evidences suggest that the axial magnetic field is the most important parameter

  17. Detailed Distribution Map of Absorbed Dose Rate in Air in Tokatsu Area of Chiba Prefecture, Japan, Constructed by Car-Borne Survey 4 Years after the Fukushima Daiichi Nuclear Power Plant Accident

    PubMed Central

    Inoue, Kazumasa; Arai, Moeko; Fujisawa, Makoto; Saito, Kyouko; Fukushi, Masahiro

    2017-01-01

    A car-borne survey was carried out in the northwestern, or Tokatsu, area of Chiba Prefecture, Japan, to make a detailed distribution map of absorbed dose rate in air four years after the Fukushima Daiichi Nuclear Power Plant accident. This area was chosen because it was the most heavily radionuclide contaminated part of Chiba Prefecture and it neighbors metropolitan Tokyo. Measurements were performed using a 3-in × 3-in NaI(Tl) scintillation spectrometer in June 2015. The survey route covered the whole Tokatsu area which includes six cities. A heterogeneous distribution of absorbed dose rate in air was observed on the dose distribution map. Especially, higher absorbed dose rates in air exceeding 80 nGy h-1 were observed along national roads constructed using high porosity asphalt, whereas lower absorbed dose rates in air were observed along local roads constructed using low porosity asphalt. The difference between these asphalt types resulted in a heterogeneous dose distribution in the Tokatsu area. The mean of the contribution ratio of artificial radionuclides to absorbed dose rate in air measured 4 years after the accident was 29% (9–50%) in the Tokatsu area. The maximum absorbed dose rate in air, 201 nGy h-1 was observed at Kashiwa City. Radiocesium was deposited in the upper 1 cm surface layer of the high porosity asphalt which was collected in Kashiwa City and the environmental half-life of the absorbed dose rate in air was estimated to be 1.7 years. PMID:28129382

  18. Mucoadhesive drug delivery systems

    PubMed Central

    Shaikh, Rahamatullah; Raj Singh, Thakur Raghu; Garland, Martin James; Woolfson, A David; Donnelly, Ryan F.

    2011-01-01

    Mucoadhesion is commonly defined as the adhesion between two materials, at least one of which is a mucosal surface. Over the past few decades, mucosal drug delivery has received a great deal of attention. Mucoadhesive dosage forms may be designed to enable prolonged retention at the site of application, providing a controlled rate of drug release for improved therapeutic outcome. Application of dosage forms to mucosal surfaces may be of benefit to drug molecules not amenable to the oral route, such as those that undergo acid degradation or extensive first-pass metabolism. The mucoadhesive ability of a dosage form is dependent upon a variety of factors, including the nature of the mucosal tissue and the physicochemical properties of the polymeric formulation. This review article aims to provide an overview of the various aspects of mucoadhesion, mucoadhesive materials, factors affecting mucoadhesion, evaluating methods, and finally various mucoadhesive drug delivery systems (buccal, nasal, ocular, gastro, vaginal, and rectal). PMID:21430958

  19. Comparative analysis of steam delivery cost for surface and downhole steam drive technologies

    SciTech Connect

    Hart, C.M.

    1981-10-01

    A basis is established for evaluating the economic performances of the technologies for enhanced recovery of heavy crude being investigated through the Department of Energy's Project DEEP STEAM. Conventional surface steam drive is compared with: (1) thermally efficient delivery (through insulated strings) of surface generated steam; (2) low pressure combustion downhole steam generation; (3) high pressure combustion downhole steam generation; (4) high pressure combustion downhole steam generation using air as the oxygen source; and (5) high pressure combustion downhole steam generation substituting pure oxygen for air. A parametric analysis is performed for varying depths, injection rates, and steam qualities.

  20. Variable delivery, fixed displacement pump

    SciTech Connect

    Sommars, Mark F.

    2001-01-01

    A variable delivery, fixed displacement pump comprises a plurality of pistons reciprocated within corresponding cylinders in a cylinder block. The pistons are reciprocated by rotation of a fixed angle swash plate connected to the pistons. The pistons and cylinders cooperate to define a plurality of fluid compression chambers each have a delivery outlet. A vent port is provided from each fluid compression chamber to vent fluid therefrom during at least a portion of the reciprocal stroke of the piston. Each piston and cylinder combination cooperates to close the associated vent port during another portion of the reciprocal stroke so that fluid is then pumped through the associated delivery outlet. The delivery rate of the pump is varied by adjusting the axial position of the swash plate relative to the cylinder block, which varies the duration of the piston stroke during which the vent port is closed.

  1. Assisted delivery with forceps

    MedlinePlus

    ... page: //medlineplus.gov/ency/patientinstructions/000509.htm Assisted delivery with forceps To use the sharing features on ... called vacuum assisted delivery . When is a Forceps Delivery Needed? Even after your cervix is fully dilated ( ...

  2. Delivery systems for brachytherapy.

    PubMed

    de la Puente, Pilar; Azab, Abdel Kareem

    2014-10-28

    Brachytherapy is described as the short distance treatment of cancer with a radioactive isotope placed on, in, or near the lesions or tumor to be treated. The main advantage of brachytherapy compared with external beam radiation (EBR) is the improved localized delivery of dose to the target volume of interest, thus normal tissue irradiation is reduced. The precise and targeted nature of brachytherapy provides a number of key benefits for the effective treatment of cancer such as efficacy, minimized risk of side effects, short treatment times, and cost-effectiveness. Brachytherapy devices have yielded promising results in preclinical and clinical studies. However, brachytherapy can only be used in localized and relatively small tumors. Although the introduction of new delivery devices allows the treatment of more complex tumor sites, with wider range of dose rate for improving treatment efficacy and reduction of side effects, a better understanding about the safety, efficacy, and accuracy of these systems is required, and further development of new techniques is warranted. Therefore, this review focuses on the delivery devices for brachytherapy and their application in prostate, breast, brain, and other tumor sites.

  3. Spectrum-dose conversion operator of NaI(Tl) and CsI(Tl) scintillation detectors for air dose rate measurement in contaminated environments.

    PubMed

    Tsuda, Shuichi; Saito, Kimiaki

    2017-01-01

    Spectrum-dose conversion operators, the G(E) functions, for common NaI(Tl) scintillation survey meters and CsI(Tl) detectors are obtained for measurements in a semi-infinite plane of contaminated ground field by photon-emitting radionuclides (ground source). The calculated doses at a height of 100 cm from the ground in (137)Cs-contaminated environments by the Monte Carlo simulation technique are compared with those obtained using the G(E) functions by assuming idealized irradiation geometries such as anterior-posterior or isotropic. The simulation reveals that one could overestimate air dose rates in the environment by a maximum of 20-30% for NaI(Tl) detectors and 40-50% for CsI(Tl) detectors depending on photon energy when using the G(E) functions assuming idealized irradiation geometries for ground source measurements. Measurements obtained after the nuclear accident in Fukushima reveal that the doses calculated using a G(E) function for a unidirectional irradiation geometry are 1.17 times higher than those calculated using a G(E) function for the ground source in the case of a CsI(Tl) scintillation detector, which has a rectangular parallelepiped crystal (13 × 13 × 20 mm(3)). However, if a G(E) function is used assuming irradiation to a surface of the detector, the doses agree with those of the ground source within 2%. These results indicate that in contaminated environments, the commonly used scintillation-based detectors overestimate doses within the acceptable limit. In addition, the degree of overestimation depends on the irradiation direction of each detector assumed for developing the G(E) function. With regard to directional dependence of the detectors, reliable air dose rates in the environment can be obtained using the G(E) function determined in unidirectional irradiation geometry, provided that the irradiation surface of the crystal is determined properly.

  4. Net carbon dioxide exchange rates and predicted growth patterns in Alstroemeria Jacqueline' at varying irradiances, carbon dioxide concentrations, and air temperatures

    SciTech Connect

    Leonardos, E.D.; Tsujita, M.J.; Grodzinski, B. . Dept. of Horticultural Science)

    1994-11-01

    The influence of irradiance, CO[sub 2] concentration, and air temperature on leaf and whole-plant net C exchange rate (NCER) of Alstroemeria Jacqueline' was studied. At ambient CO[sub 2], leaf net photosynthesis was maximum at irradiances above 600 [mu]mol[center dot]m[sup [minus]2][center dot]s[sup [minus]1] photosynthetically active radiation (PAR), while whole-plant NCER required 1,200 [mu]mol[center dot]m[sup [minus]2][center dot]s[sup [minus]1] PAR to be saturated. Leaf and whole-plant NCERs were doubled under CO[sub 2] enrichment of 1,500 to 2,000 [mu]l CO[sub 2]/liter. Leaf and whole-plant NCERs declined as temperature increased from 20 to 35 C. Whereas the optimum temperature range for leaf net photosynthesis was 17 to 23 C, whole-plant NCER, even at high light and high CO[sub 2], declined above 12 C. Dark respiration of leaves and whole plants increased with a Q[sub 10] of [approx] 2 at 15 to 35 C. In an analysis of day effects, irradiance, CO[sub 2] concentration, and temperature contributed 58%, 23%, and 14%, respectively, to the total variation in NCER explained by a second-order polynomial model (R[sup 2] = 0.85). Interactions among the factors accounted for 4% of the variation in day C assimilation. The potential whole-plant growth rates during varying greenhouse day and night temperature regimes were predicted for short- and long-day scenarios. The data are discussed with the view of designing experiments to test the importance of C gain in supporting flowering and high yield during routine harvest of Alstroemeria plants under commercial greenhouse conditions.

  5. Effect of indoor air pollution during cooking on peak expiratory flow rate and its association with exposure index in rural women.

    PubMed

    Sukhsohale, Neelam D; Narlawar, Uday W; Phatak, Mrunal S; Agrawal, Sanjay B; Ughade, Suresh N

    2013-01-01

    Routine exposure to domestic cooking fuels is an important source of indoor air pollution causing deterioration of lung function. We conducted a community based cross-sectional study in 760 non-smoking rural women involved in household cooking with four types of cooking fuels i.e. Biomass, Kerosene stove, Liquid Petroleum Gas (LPG) and Mixed (combination of two and more cooking fuels). Peak Expiratory Flow Rate (PEFR) less than 80% of the predicted was considered as abnormal PEFR. The overall prevalence of abnormal PEFR was found to be 29.1% with greater predominance among biomass fuel users (43.3%) with high risk ratio (1.86) as compared to kerosene (0.63), LPG (0.75) and mixed (0.66) fuel users. However the pair wise comparison of different groups of cooking fuels by Marascuilo procedure reported significant differences within different groups except kerosene--mixed group. The study also demonstrated a negative correlation between observed PEFR and exposure indices in different cooking fuels (r = -0.51). Our results indicate that prolonged exposure to cooking fuels particularly biomass fuels as a source of cooking adversely affects PEFR in nonsmoking rural women.

  6. Analysis of specific absorption rate and internal electric field in human biological tissues surrounding an air-core coil-type transcutaneous energy transmission transformer.

    PubMed

    Shiba, Kenji; Zulkifli, Nur Elina Binti; Ishioka, Yuji

    2016-11-21

    In this study, we analyzed the internal electric field E and specific absorption rate (SAR) of human biological tissues surrounding an air-core coil transcutaneous energy transmission transformer. Using an electromagnetic simulator, we created a model of human biological tissues consisting of a dry skin, wet skin, fat, muscle, and cortical bone. A primary coil was placed on the surface of the skin, and a secondary coil was located subcutaneously inside the body. The E and SAR values for the model representing a 34-year-old male subject were analyzed using electrical frequencies of 0.3-1.5 MHz. The transmitting power was 15 W, and the load resistance was 38.4 Ω. The results showed that the E values were below the International Commission on Non-ionizing Radiation Protection (ICNIRP) limit for the general public exposure between the frequencies of 0.9 and 1.5 MHz, and SAR values were well below the limit prescribed by the ICNIRP for the general public exposure between the frequencies of 0.3 and 1.2 MHz.

  7. SAROTA: application of specific absorption rate (SAR) and over-the-air (OTA) data for the characterization of the real-life exposure due to mobile phones

    NASA Astrophysics Data System (ADS)

    Monebhurrun, Vikass

    2013-04-01

    The RF exposure level of a mobile phone is quantified by the measurement of the specific absorption rate (SAR) under laboratory conditions. The SAR which is measured while the mobile phone is operated at maximum power level does not reflect the real-life exposure scenario since the mobile phone typically re-adjusts its power level and frequency depending on the quality of the communication link with the nearest base station. The choice of a low RF exposure device based on the comparison of the relative SAR values of mobile phones can be misleading. The real-life RF exposure also depends on the over-the-air (OTA) performance of the mobile phone. Taken independently, the two sets of data do not allow a straightforward comparison of the global RF performance amongst mobile phones. A unique and simple parameter denoted as the SAROTA index is proposed for the characterization of mobile phones with regard to both RF exposure and OTA performance. The SAROTA index provides the real-life exposure index of the mobile phone.

  8. Effect of forward rapidly rotating shift work on circadian rhythms of arterial pressure, heart rate and oral temperature in air traffic controllers.

    PubMed

    Stoynev, A G; Minkova, N K

    1998-02-01

    Twenty-four-hour records of arterial pressure (AP), heart rate (HR), oral temperature (OT) and physical and mental performance were obtained in air traffic controllers during morning (n = 16), afternoon (n = 17) and night (n = 19) shifts. Data were analyzed by the cosinor method. The results obtained during the morning shift were as follows (mesor/amplitude/acrophase): systolic AP (mm Hg)--113.6/10.0/16:03 h; diastolic AP--71.1/8.2/15:19 h; mean AP--85.6/8.8/15:41 h; HR (beats/min)--77.5/8.9/16:00 h; OT (dg C)--36.71/0.21/15:49 h; right-hand grip strength (kg)--49.8/2.0/17:43 h; left-hand grip strength--46.1/2.0/16:08 h; mental performance (calculations/min)--14.9/1.1/16:39 h. During the night shift either no change of the circadian acrophases (HR, right-hand grip strength) or acrophase delays ranging from about 2 h (systolic AP, OT, mental performance) up to 3 h (diastolic and mean AP, left-hand grip strength) were observed. Our data suggest that the shift system studied does not significantly alter the circadian rhythms, and does not induce a desynchronization, particularly as concerns arterial pressure and oral temperature.

  9. Balancing energy conservation and occupant needs in ventilation rate standards for Big Box stores and other commercial buildings in California. Issues related to the ASHRAE 62.1 Indoor Air Quality Procedure

    SciTech Connect

    Mendell, Mark J.; Apte, Mike G.

    2010-10-31

    This report considers the question of whether the California Energy Commission should incorporate the ASHRAE 62.1 ventilation standard into the Title 24 ventilation rate (VR) standards, thus allowing buildings to follow the Indoor Air Quality Procedure. This, in contrast to the current prescriptive standard, allows the option of using ventilation rate as one of several strategies, which might include source reduction and air cleaning, to meet specified targets of indoor air concentrations and occupant acceptability. The research findings reviewed in this report suggest that a revised approach to a ventilation standard for commercial buildings is necessary, because the current prescriptive ASHRAE 62.1 Ventilation Rate Procedure (VRP) apparently does not provide occupants with either sufficiently acceptable or sufficiently healthprotective air quality. One possible solution would be a dramatic increase in the minimum ventilation rates (VRs) prescribed by a VRP. This solution, however, is not feasible for at least three reasons: the current need to reduce energy use rather than increase it further, the problem of polluted outdoor air in many cities, and the apparent limited ability of increasing VRs to reduce all indoor airborne contaminants of concern (per Hodgson (2003)). Any feasible solution is thus likely to include methods of pollutant reduction other than increased outdoor air ventilation; e.g., source reduction or air cleaning. The alternative 62.1 Indoor Air Quality Procedure (IAQP) offers multiple possible benefits in this direction over the VRP, but seems too limited by insufficient specifications and inadequate available data to provide adequate protection for occupants. Ventilation system designers rarely choose to use it, finding it too arbitrary and requiring use of much non-engineering judgment and information that is not readily available. This report suggests strategies to revise the current ASHRAE IAQP to reduce its current limitations. These

  10. Spontaneous diaphragm rupture associated with vaginal delivery.

    PubMed

    Hamaji, Masatsugu; Burt, Bryan M; Ali, Syed Osman; Cohen, Daniel M

    2013-08-01

    Spontaneous rupture of the diaphragm associated with vaginal delivery is a rare occurrence, but has high rates of morbidity and mortality. Herein, we present a first uncomplicated case of spontaneous rupture of the diaphragm associated with vaginal delivery, which was treated successfully with surgery via a thoracotomy.

  11. Software Build and Delivery Systems

    SciTech Connect

    Robey, Robert W.

    2016-07-10

    This presentation deals with the hierarchy of software build and delivery systems. One of the goals is to maximize the success rate of new users and developers when first trying your software. First impressions are important. Early successes are important. This also reduces critical documentation costs. This is a presentation focused on computer science and goes into detail about code documentation.

  12. Ocular delivery of macromolecules

    PubMed Central

    Kim, Yoo-Chun; Chiang, Bryce; Wu, Xianggen; Prausnitz, Mark R.

    2014-01-01

    Biopharmaceuticals are making increasing impact on medicine, including treatment of indications in the eye. Macromolecular drugs are typically given by physician-administered invasive delivery methods, because non--invasive ocular delivery methods, such as eye drops, and systemic delivery, have low bioavailability and/or poor ocular targeting. There is a need to improve delivery of biopharmaceuticals to enable less-invasive delivery routes, less-frequent dosing through controlled-release drug delivery and improved drug targeting within the eye to increase efficacy and reduce side effects. This review discusses the barriers to drug delivery via various ophthalmic routes of administration in the context of macromolecule delivery and discusses efforts to develop controlled-release systems for delivery of biopharmaceuticals to the eye. The growing number of macromolecular therapies in the eye needs improved drug delivery methods that increase drug efficacy, safety and patient compliance. PMID:24998941

  13. State-of-the-Art Survey of Hardware Delivery and Damage Inspection Methods for Coast Guard Hazardous Chemical Spill Response.

    DTIC Science & Technology

    1980-08-01

    deck decompression chamber. A special breathing gas mixture is often used in this mode. For underwater jobs at a deep depth which require extensive...air/water inflatable bags)9 3, Delivery of a chemical sensor for venting rate measurements , sampling, and analysis for the detection, identification...and subjected to a weighted factor evaluation. The results of the evaluation indicate the most promising approach is through the application of a

  14. Isokinetic air sampler

    DOEpatents

    Sehmel, George A.

    1979-01-01

    An isokinetic air sampler includes a filter, a holder for the filter, an air pump for drawing air through the filter at a fixed, predetermined rate, an inlet assembly for the sampler having an inlet opening therein of a size such that isokinetic air sampling is obtained at a particular wind speed, a closure for the inlet opening and means for simultaneously opening the closure and turning on the air pump when the wind speed is such that isokinetic air sampling is obtained. A system incorporating a plurality of such samplers provided with air pumps set to draw air through the filter at the same fixed, predetermined rate and having different inlet opening sizes for use at different wind speeds is included within the ambit of the present invention as is a method of sampling air to measure airborne concentrations of particulate pollutants as a function of wind speed.

  15. Radiological assessment of water treatment processes in a water treatment plant in Saudi Arabia: Water and sludge radium content, radon air concentrations and dose rates.

    PubMed

    Al-Jaseem, Q Kh; Almasoud, Fahad I; Ababneh, Anas M; Al-Hobaib, A S

    2016-09-01

    There is an increase demand for clean water sources in Saudi Arabia and, yet, renewable water resources are very limited. This has forced the authorities to explore deep groundwater which is known to contain large concentrations of radionuclides, mainly radium isotopes. Lately, there has been an increase in the number of water treatment plants (WTPs) around the country. In this study, a radiological assessment of a WTP in Saudi Arabia was performed. Raw water was found to have total radium activity of 0.23Bq/L, which exceeds the international limit of 0.185Bq/L (5pCi/L). The WTP investigated uses three stages of treatment: flocculation/sedimentation, sand filtration and reverse osmosis. The radium removal efficiency was evaluated for each stage and the respective values were 33%, 22% and 98%. Moreover, the activity of radium in the solid waste generated from the WTP in the sedimentation and sand filtrations stages were measured and found to be 4490 and 6750Bq/kg, respectively, which exceed the national limit of 1000Bq/kg for radioactive waste. A radiological assessment of the air inside the WTP was also performed by measuring the radon concentrations and dose rates and were found in the ranges of 2-18Bq/m(3) and 70-1000nSv/h, respectively. The annual effective dose was calculated and the average values was found to be 0.3mSv which is below the 1mSv limit.

  16. Design and stable flight of a 21 g insect-like tailless flapping wing micro air vehicle with angular rates feedback control.

    PubMed

    Phan, Hoang Vu; Kang, Taesam; Park, Hoon Cheol

    2017-04-04

    An insect-like tailless flapping wing micro air vehicle (FW-MAV) without feedback control eventually becomes unstable after takeoff. Flying an insect-like tailless FW-MAV is more challenging than flying a bird-like tailed FW-MAV, due to the difference in control principles. This work introduces the design and controlled flight of an insect-like tailless FW-MAV, named KUBeetle. A combination of four-bar linkage and pulley-string mechanisms was used to develop a lightweight flapping mechanism that could achieve a high flapping amplitude of approximately 190°. Clap-and-flings at dorsal and ventral stroke reversals were implemented to enhance vertical force. In the absence of a control surface at the tail, adjustment of the location of the trailing edges at the wing roots to modulate the rotational angle of the wings was used to generate control moments for the attitude control. Measurements by a 6-axis load cell showed that the control mechanism produced reasonable pitch, roll and yaw moments according to the corresponding control inputs. The control mechanism was integrated with three sub-micro servos to realize the pitch, roll and yaw controls. A simple PD feedback controller was implemented for flight stability with an onboard microcontroller and a gyroscope that sensed the pitch, roll and yaw rates. Several flight tests demonstrated that the tailless KUBeetle could successfully perform a vertical climb, then hover and loiter within a 0.3 m ground radius with small variations in pitch and roll body angles.

  17. A laboratory study examining the impact of linen use on low-air-loss support surface heat and water vapor transmission rates.

    PubMed

    Williamson, Rachel; Lachenbruch, Charlie; VanGilder, Catherine

    2013-08-01

    Layers of linens are frequently placed under patients to manage moisture and/or assist with positioning immobile patients, including persons placed on a therapeutic surface because they are at risk for developing pressure ulcers. Because skin microclimate is believed to affect pressure ulcer risk, some therapeutic surfaces are designed to manage skin temperature and humidity (microclimate management). The purpose of this study was to measure the effects of linens and underpads on a low-air-loss (LAL) surface's ability to disperse heat and evaporate moisture. Underpads and transfer sheet combinations (grouped by three common linen functions: immobility, moisture management, and immobility and moisture management) were tested using the sweating guarded hot plate method, which allows for the measurement of the evaporative capacity (g H2O/m2*hour) and the total rate of heat withdrawal (Watts/m2) associated with nine different linen configurations placed on the support surface. Total heat withdrawal and evaporative capacity of the LAL surface with a fitted sheet only was used for comparison (P <0.05) Compared with fitted sheet only, heat withdrawal was significantly reduced by five of eight combinations, and evaporative moisture reduction was significantly reduced by six of eight linen combinations (P <0.05). All combinations that included plastic-containing underpads significantly reduced the surface's ability to dissipate heat and evaporate moisture, and use of the maximum number of layers (nine) reduced heat withdrawal to the level of a static, nonLAL surface. The results of this study suggest that putting additional linens or underpads on LAL surfaces may adversely affect skin temperature and moisture, thereby reducing the pressure ulcer prevention potential of these surfaces. Additional studies to examine the effect of linens and underpads as well as microclimate management strategies on pressure ulcer risk are needed.

  18. Radiological investigations at the "Taiga" nuclear explosion site, part II: man-made γ-ray emitting radionuclides in the ground and the resultant kerma rate in air.

    PubMed

    Ramzaev, V; Repin, V; Medvedev, A; Khramtsov, E; Timofeeva, M; Yakovlev, V

    2012-07-01

    Samples of soil and epigeic lichens were collected from the "Taiga" peaceful nuclear explosion site (61.30°N 56.60°E, the Perm region, Russia) in 2009 and analyzed using high resolution γ-ray spectrometry. For soil samples obtained at six different plots, two products of fission ((137)Cs and (155)Eu), five products of neutron activation ((60)Co, (94)Nb, (152)Eu, (154)Eu, (207)Bi) and (241)Am have been identified and quantified. The maximal activity concentrations of (60)Co, (137)Cs, and (241)Am for the soils samples were measured as 1650, 7100, and 6800 Bq kg(-1) (d.w.), respectively. The deposit of (137)Cs for the top 20 cm of soil on the tested plots at the "Taiga" site ranged from 30 to 1020 kBq m(-2); the maximal value greatly (by almost 3 orders of magnitude) exceeded the regional background (from global fallout) level of 1.4 kBq m(-2). (137)Cs contributes approximately 57% of the total ground inventory of the man-made γ-ray emitters for the six plots tested at the "Taiga" site. The other major radionuclides -(241)Am and (60)Co, constitute around 40%. Such radionuclides as (60)Co, (137)Cs, (241)Am, and (207)Bi have also been determined for the epigeic lichens (genera Cladonia) that colonized certain areas at the ground lip produced by the "Taiga" explosion. Maximal activity concentrations (up to 80 Bq kg(-1) for (60)Co, 580 Bq kg(-1) for (137)Cs, 200 Bq kg(-1) for (241)Am, and 5 Bq kg(-1) for (207)Bi; all are given in terms of d.w.) have been detected for the lower dead section of the organisms. The air kerma rates associated with the anthropogenic sources of gamma radiation have been calculated using the data obtained from the laboratory analysis. For the six plots tested, the kerma rates ranged from 50 to 1200 nGy h(-1); on average, 51% of the dose can be attributed to (137)Cs and 45% to (60)Co. These estimates agree reasonably well with the results of the in situ measurements made during our field survey of the "Taiga" site in August

  19. 32 CFR 935.93 - Delivery of summons to plaintiff.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 32 National Defense 6 2011-07-01 2011-07-01 false Delivery of summons to plaintiff. 935.93 Section 935.93 National Defense Department of Defense (Continued) DEPARTMENT OF THE AIR FORCE TERRITORIAL AND INSULAR REGULATIONS WAKE ISLAND CODE Civil Actions § 935.93 Delivery of summons to plaintiff. The Clerk...

  20. 7. VIEW OF WEAPONS DELIVERY ROAD CULVERT OF LOWER DIAGONAL ...

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

    7. VIEW OF WEAPONS DELIVERY ROAD CULVERT OF LOWER DIAGONAL NO. 1 DRAIN, LOOKING 522 EAST OF NORTH. - Truckee-Carson Irrigation District, Lower Diagonal No. 1 Drain, Bounded by West Gate Road & Weapons Delivery Road, Naval Air Station Fallon, Fallon, Churchill County, NV

  1. Photocatalytic air purifiers for indoor air: European standard and pilot room experiments.

    PubMed

    Costarramone, N; Cantau, C; Desauziers, V; Pécheyran, C; Pigot, T; Lacombe, S

    2016-09-15

    At the European level (CEN/TC386), some efforts are currently devoted to new standards for comparing the efficiency of commercial photocatalytic material/devices in various application fields. Concerning prototype or commercial indoor photocatalytic air purifiers designed for volatile organic compounds (VOC) abatement, the methodology is based on a laboratory airtight chamber. The photocatalytic function is demonstrated by the mineralization of a mixture of five VOCs. Experimental data were obtained for four selected commercial devices and three commercial materials: drop of VOC concentration, but also identification of secondary species (with special attention to formaldehyde), mineralization rates, and Clean Air Delivery Rate (CADR). With two efficient air purifiers, these laboratory experiments were compared to the results in two experimental rooms (35-40 m(3)) where air pollution was introduced through wooden floor and furniture. The systems' ageing was also studied. The safety of the commercial products was also assessed by the determination of nanoparticle release. Standardized tests are useful to rank photocatalytic air purifiers and passive materials and to discard inefficient ones. A good correlation between the standard experiments and the experimental room experiments was found, even if in the latter case, the concentration of lower weight VOCs drops less quickly than that of heavier VOCs.

  2. Comparison of six oxygen delivery systems for COPD patients at rest and during exercise.

    PubMed

    Braun, S R; Spratt, G; Scott, G C; Ellersieck, M

    1992-09-01

    Five different oxygen-conserving devices were tested in each of ten oxygen-dependent patients with COPD who had met the NOTT criteria for continuous oxygen use. They were tested on room air, their prescribed continuous oxygen flow and then on each of the five devices. The devices which delivered a bolus of oxygen during early inspiration or increased oxygen delivery as the respiratory rate increased did better than those devices which delivered oxygen at a normal flow rate during inspiration or a fixed portion of inspiration. In at least one of the subjects each device was associated with desaturation to less than 80 percent during a 12-min walk. It is concluded that oxygen-conserving devices vary in their ability to maintain SaO2 levels during exercise. It is recommended that a home oxygen evaluation include measurement of an exercise SaO2 utilizing the prescribed oxygen delivery system.

  3. [On the question of occurrence and the problem of hygiene rating of fungal air pollution of the environment of residential and public buildings].

    PubMed

    Gubernskiĭ, Iu D; Beliaeva, N N; Kalinina, N V; Mel'nikova, A I; Chuprina, O V

    2013-01-01

    Comprehensive sanitary examinations of fungal pollution of the environment of residential and public buildings were performed. There is established the occurrence of sensitization of the population associated with the fungal contamination of the wallings of buildings and presence of viable mold spores in the indoor air environment. Major factors determining the degree of fungal contamination of indoor environments: increasing humidity of indoor air due to leaks and bays, the area of enclosure structures and the temperature factor have been identified.

  4. Bladder Injury During Cesarean Delivery

    PubMed Central

    Tarney, Christopher M.

    2013-01-01

    Cesarean section is the most common surgery performed in the United States with over 30% of deliveries occurring via this route. This number is likely to increase given decreasing rates of vaginal birth after cesarean section (VBAC) and primary cesarean delivery on maternal request, which carries the inherent risk for intraoperative complications. Urologic injury is the most common injury at the time of either obstetric or gynecologic surgery, with the bladder being the most frequent organ damaged. Risk factors for bladder injury during cesarean section include previous cesarean delivery, adhesions, emergent cesarean delivery, and cesarean section performed at the time of the second stage of labor. Fortunately, most bladder injuries are recognized at the time of surgery, which is important, as quick recognition and repair are associated with a significant reduction in patient mortality. Although cesarean delivery is a cornerstone of obstetrics, there is a paucity of data in the literature either supporting or refuting specific techniques that are performed today. There is evidence to support double-layer closure of the hysterotomy, the routine use of adhesive barriers, and performing a Pfannenstiel skin incision versus a vertical midline subumbilical incision to decrease the risk for bladder injury during cesarean section. There is also no evidence that supports the creation of a bladder flap, although routinely performed during cesarean section, as a method to reduce the risk of bladder injury. Finally, more research is needed to determine if indwelling catheterization, exteriorization of the uterus, and methods to extend hysterotomy incision lead to bladder injury. PMID:24876830

  5. Air Research

    EPA Pesticide Factsheets

    EPA's air research provides the critical science to develop and implement outdoor air regulations under the Clean Air Act and puts new tools and information in the hands of air quality managers and regulators to protect the air we breathe.

  6. Vacuum-assisted delivery

    MedlinePlus

    ... this page: //medlineplus.gov/ency/patientinstructions/000514.htm Vacuum-assisted delivery To use the sharing features on ... the baby through the birth canal. When is Vacuum-assisted Delivery Needed? Even after your cervix is ...

  7. Once more unto the breech: planned vaginal delivery compared with planned cesarean delivery.

    PubMed

    Joseph, K S; Pressey, Tracy; Lyons, Janet; Bartholomew, Sharon; Liu, Shiliang; Muraca, Giulia; Liston, Robert M

    2015-05-01

    This article provides a knowledge-based assessment of planned cesarean delivery compared with planned vaginal delivery for breech presentation at term gestation. The most critical evidence on this issue is the intention-to-treat analysis from the Term Breech Trial, which showed that planned cesarean delivery reduced composite perinatal death and serious neonatal morbidity. Although there was no difference in composite death or neurodevelopmental delay at 2 years of age, this finding was based on only 44% of randomized patients and was not an analysis by intention to treat. On the other hand, the design of the nonexperimental Presentation et Mode d'Accouchement: presentation and mode of delivery (PREMODA) study (which showed no difference in composite perinatal mortality or morbidity after planned cesarean delivery compared with planned vaginal delivery), likely favored the planned vaginal delivery group; lack of exclusion criteria led to higher risk women (with contraindications to vaginal delivery) being included in the planned cesarean delivery group. Such selection bias notwithstanding, both the Term Breech Trial and the PREMODA study showed significantly higher rates of 5-minute Apgar score less than 4, 5-minute Apgar score less than 7, intubation, and birth trauma in the planned vaginal delivery group. Finally, studies from the Netherlands, Denmark, and Canada have shown that increases in planned cesarean delivery after the Term Breech Trial led to improved neonatal outcomes. Nevertheless, planned vaginal delivery continues to be associated with higher rates of adverse perinatal outcomes in these countries. The totality of the evidence therefore unequivocally shows the relatively greater safety of planned cesarean delivery for breech presentation at term gestation.

  8. [Interventions during labor for reducing instrumental deliveries].

    PubMed

    Schmitz, T; Meunier, E

    2008-12-01

    Several interventions have been demonstrated, with high evidence levels (EL), to be associated with reduced instrumental deliveries and should therefore be undertaken during labor for increasing spontaneous vaginal deliveries. Using a partogram (EL1) and continuous support during labor and childbirth (EL1) lead to fewer operative vaginal deliveries. Systematic early amniotomy increases the frequency of fetal heart rate abnormalities (EL2) without decreasing the incidence of instrumental deliveries (EL1) and should thus be avoided. Early oxytocin in dysfunctional labor (EL2) and manual rotation of posterior and transverse presentations (EL3) may reduce operative vaginal deliveries. Even without epidural analgesia, any upright or lateral positions compared to supine or lithotomy positions do not reduce instrumental deliveries (EL2). Epidural analgesia alters significantly instrumental delivery rates and therefore patient management in the labor ward. Indeed, when used with high concentration of local anesthetic, epidural analgesia is associated with increased operative vaginal deliveries (EL1), at least in part because of increased posterior presentations (EL2). However, the effect of epidural analgesia on instrumental delivery rates closely depends from the type of anesthetic and concentrations used. This effect is reduced when low concentrations of local anesthetic are used in combination with fat-soluble morphinated agent (EL1). Finally, for nulliparous women with continuous epidural analgesia, unless irresistible urge to push or medical indication to shorten second stage of labor, delayed pushing is associated with reduced difficult instrumental deliveries (EL1). Fundal pressure maneuvers should be prohibited because of their inefficiency (EL2) and dangerousness (EL4).

  9. Post caesarean section delivery.

    PubMed

    Bolaji, I I; Meehan, F P

    1993-10-29

    Recent clinical attention has focused upon the rising rate of caesarean sections being performed and whether patients with a previous caesarean section should be allowed a vaginal delivery. In this paper, the worldwide trend of caesarean section and the role of trial of scar following single and multiple caesarean surgery is reviewed. The role of oxytocin and regional epidural analgesia is evaluated as well as perinatal and maternal mortality. On the basis of the available data, there is no justification for the current clinical practice of almost 99% prevalence of elective repeat caesarean section in some hospitals in the North America. Oxytocin and epidural analgesia, when carefully monitored, are safe and reasonable in these patients. Watchful waiting has always been an essential virtue in obstetric management and should not be replaced by hopeful expectancy. This aspect of the art of obstetrics would appear to require rejuvenation if we are to stem the rising tide of caesarean sections.

  10. Articulating feedstock delivery device

    SciTech Connect

    Jordan, Kevin

    2013-11-05

    A fully articulable feedstock delivery device that is designed to operate at pressure and temperature extremes. The device incorporates an articulating ball assembly which allows for more accurate delivery of the feedstock to a target location. The device is suitable for a variety of applications including, but not limited to, delivery of feedstock to a high-pressure reaction chamber or process zone.

  11. Postpartum sterilization in cesarean section and non-cesarean section deliveries: United States, 1970-75.

    PubMed Central

    Placek, P J; Taffel, S M; Smith, J C; Maze, J M

    1981-01-01

    National Hospital Discharge Survey data indicate that the overall postpartum sterilization rate per 100 deliveries increased by 75 per cent from 4.0 in 1970 to 7.0 in 1975; by type of delivery, rates rose from 18.0 per 100 cesarean section deliveries and 3.2 for all other deliveries in 1970 to 19.0 and 5.6 respectively in 1975. The South had the highest postpartum sterilization rates overall. Deliveries to older mothers and cesarean section deliveries in hospitals with less than 100 beds were more often characterized by higher sterilization rates. PMID:7294272

  12. Protective supplied-breathing-air garment

    DOEpatents

    Childers, E.L.; von Hortenau, E.F.

    1982-05-28

    A breathing-air garment for isolating a wearer from hostile environments containing toxins or irritants is disclosed. The garment includes a suit and a separate head-protective enclosure or hood engaging a suit collar in sealing attachment. The hood and suit collar are cylindrically shaped and dimensioned to enable the wearer to withdraw his hands from the suit sleeves to perform manual tasks within the hood interior. Breathing air is supplied from an external air line with an air-delivery hose attached to the hood interior. The hose feeds air into an annular halo-like fiber-filled plenum having spaced discharge orifices attached to the hood top wall. A plurality of air exhaust/check valves located at the suit extremities cooperate with the hood air-delivery system to provide a cooling flow of circulating air from the hood throughout the suit interior. A suit entry seal provided on the suit sealed with an adhesive sealing flap.

  13. Colloidal drug delivery systems in vaccine delivery.

    PubMed

    Beg, Sarwar; Samad, Abdus; Nazish, Iram; Sultana, Ruksar; Rahman, Mahfoozur; Ahmad, Md Zaki; Akbar, Md

    2013-01-01

    Vaccines play a vital role in the field of community medicine to combat against several diseases of human existence. Vaccines primarily trigger the acquired immune system to develop long-lasting immunity against pathogens. Conventional approaches for vaccine delivery lacks potential to target a particular antigen to develop acquired immunity by specific antibodies. Recent advancements in vaccine delivery showed that inclusion of adjuvants in vaccine formulations or delivery of them in a carrier helps in achieving desired targeting ability, reducing the immunogenicity and significant augmentation in the immune response. Colloidal carriers (liposomes, niosomes, microspheres, proteosomes, virosomes and virus like particles (VLPs), antigen cochleates, dendrimers and carbon nanotubes) have been widely explored for vaccine delivery. Further, surface engineering of these carriers with ligands, functional moieties and monoclonal antibodies tend to enhance the immune recognition potential of vaccines by differentiation of antigen specific memory T-cells. The current review, therefore, provides an updated account on the recent advancements in various colloidal delivery systems in vaccine delivery, outlining the mechanism of immune response initiated by them along with potential applications and marketed instances in an explicit manner.

  14. Long-term maternal morbidity associated with repeat cesarean delivery.

    PubMed

    Clark, Erin A S; Silver, Robert M

    2011-12-01

    Concern regarding the association between cesarean delivery and long-term maternal morbidity is growing as the rate of cesarean delivery continues to increase. Observational evidence suggests that the risk of morbidity increases with increasing number of cesarean deliveries. The dominant maternal risk in subsequent pregnancies is placenta accreta spectrum disorder and its associated complications. A history of multiple cesarean deliveries is the major risk factor for this condition. Pregnancies following cesarean delivery also have increased risk for other types of abnormal placentation, reduced fetal growth, preterm birth, and possibly stillbirth. Chronic maternal morbidities associated with cesarean delivery include pelvic pain and adhesions. Adverse reproductive effects may include decreased fertility and increased risk of spontaneous abortion and ectopic pregnancy. Clinicians and patients need to be aware of the long-term risks associated with cesarean delivery so that they can be considered when determining the method of delivery for first and subsequent births.

  15. [Timing, place and method of delivery in twin pregnancy].

    PubMed

    Nikolov, A

    2011-01-01

    Over the past years, rate and number of twin births have increased, in general, due to innovations in infertility treatment. Delivery in twin pregnancy has its own specifics in the three periods of delivery. Contemporary tendencies in twin pregnancy management and elective birth timing are been reviewed in this article. The general rules defining the place of delivery and general organizational and diagnostic problems are outlined. The methods of delivery are discussed in detail whereby types of incisions and anesthesiological specifics for abdominal operative delivery are focused. Contemporary possibilities for vaginal delivery are described as well as methods and specifics of the anesthesia. The knowledge of the specifics of twin pregnancy delivery as well as the definition of time and place of delivery is of high significance for successful perinatal outcome and long-term prognosis.

  16. /Air Atmospheres

    NASA Astrophysics Data System (ADS)

    Emami, Samar; Sohn, Hong Yong; Kim, Hang Goo

    2014-08-01

    Molten magnesium oxidizes rapidly when exposed to air causing melt loss and handling difficulties. The use of certain additive gases such as SF6, SO2, and CO2 to form a protective MgO layer over a magnesium melt has been proposed. The oxidation behavior of molten magnesium in air containing various concentrations of SF6 was investigated. Measurements of the kinetics of the oxide layer growth at various SF6 concentrations in air and temperatures were made. Experiments were performed using a thermogravimetric analysis unit in the temperature range of 943 K to 1043 K (670 °C to 770 °C). Results showed that a thin, coherent, and protective MgF2 layer was formed under SF6/Air mixtures, with a thickness ranging from 300 nm to 3 μm depending on SF6 concentration, temperature, and exposure time. Rate parameters were calculated and a model for the process was developed. The morphology and composition of the surface films were studied using scanning electron microscope and energy-dispersive spectroscope.

  17. Do time-averaged, whole-building, effective volatile organic compound (VOC) emissions depend on the air exchange rate? A statistical analysis of trends for 46 VOCs in U.S. offices.

    PubMed

    Rackes, A; Waring, M S

    2016-08-01

    We used existing data to develop distributions of time-averaged air exchange rates (AER), whole-building 'effective' emission rates of volatile organic compounds (VOC), and other variables for use in Monte Carlo analyses of U.S. offices. With these, we explored whether long-term VOC emission rates were related to the AER over the sector, as has been observed in the short term for some VOCs in single buildings. We fit and compared two statistical models to the data. In the independent emissions model (IEM), emissions were unaffected by other variables, while in the dependent emissions model (DEM), emissions responded to the AER via coupling through a conceptual boundary layer between the air and a lumped emission source. For 20 of 46 VOCs, the DEM was preferable to the IEM and emission rates, though variable, were higher in buildings with higher AERs. Most oxygenated VOCs and some alkanes were well fit by the DEM, while nearly all aromatics and halocarbons were independent. Trends by vapor pressure suggested multiple mechanisms could be involved. The factors of temperature, relative humidity, and building age were almost never associated with effective emission rates. Our findings suggest that effective emissions in real commercial buildings will be difficult to predict from deterministic experiments or models.

  18. 76 FR 51847 - Air Cargo Screening

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-18

    ... apply to international inbound cargo. \\2\\ 74 FR 47672. The IFR provides detailed information on TSA's..., Express Delivery and Logistics Association, International Air Transport Association, Meridian One... for international inbound cargo. TSA Response: TSA is working closely with its foreign...

  19. Air conditioning system

    DOEpatents

    Lowenstein, Andrew; Miller, Jeffrey; Gruendeman, Peter; DaSilva, Michael

    2005-02-01

    An air conditioner comprises a plurality of plates arranged in a successively stacked configuration with portions thereof having a spaced apart arrangement, and defining between successive adjacent pairs of plates at the spaced apart portions a first and second series of discrete alternating passages wherein a first air stream is passed through the first series of passages and a second air stream is passed through the second series of passages; and said stacked configuration of plates forming integrally therewith a liquid delivery means for delivering from a source a sufficient quantity of a liquid to the inside surfaces of the first series of fluid passages in a manner which provides a continuous flow of the liquid from a first end to a second end of the plurality of plates while in contact with the first air stream.

  20. Prodrug Strategies in Ocular Drug Delivery

    PubMed Central

    Barot, Megha; Bagui, Mahuya; Gokulgandhi, Mitan R.; Mitra, Ashim K.

    2015-01-01

    Poor bioavailability of topically instilled drug is the major concern in the field of ocular drug delivery. Efflux transporters, static and dynamic ocular barriers often possess rate limiting factors for ocular drug therapy. Different formulation strategies like suspension, ointment, gels, nanoparticles, implants, dendrimers and liposomes have been employed in order to improve drug permeation and retention by evading rate limiting factors at the site of absorption. Chemical modification such as prodrug targeting various nutrient transporters (amino acids, peptide and vitamin) has evolved a great deal ofintereSt to improve ocular drug delivery. In this review, we have discussed various prodrug strategies which have been widely applied for enhancing therapeutic efficacy of ophthalmic drugs. The purpose of this review is to provide an update on the utilization of prodrug concept in ocular drug delivery. In addition, this review will highlight ongoing academic and industrial research and development in terms of ocular prodrug design and delivery. PMID:22530907

  1. Air Pollution

    MedlinePlus

    Air pollution is a mixture of solid particles and gases in the air. Car emissions, chemicals from factories, ... Ozone, a gas, is a major part of air pollution in cities. When ozone forms air pollution, it's ...

  2. Final Report Balancing energy conservation and occupant needs in ventilation rate standards for Big Box stores in California. Predicted indoor air quality and energy consumption using a matrix of ventilation scenarios

    SciTech Connect

    Apte, Michael G.; Mendell, Mark J.; Sohn, Michael D.; Dutton, Spencer M.; Berkeley, Pam M.; Spears, Michael

    2011-02-01

    Through mass-balance modeling of various ventilation scenarios that might satisfy the ASHRAE 62.1 Indoor Air Quality (IAQ) Procedure, we estimate indoor concentrations of contaminants of concern (COCs) in California “big box” stores, compare estimates to available thresholds, and for selected scenarios estimate differences in energy consumption. Findings are intended to inform decisions on adding performance-based approaches to ventilation rate (VR) standards for commercial buildings. Using multi-zone mass-balance models and available contaminant source rates, we estimated concentrations of 34 COCs for multiple ventilation scenarios: VRmin (0.04 cfm/ft2 ), VRmax (0.24 cfm/ft2 ), and VRmid (0.14 cfm/ft2 ). We compared COC concentrations with available health, olfactory, and irritant thresholds. We estimated building energy consumption at different VRs using a previously developed EnergyPlus model. VRmax did control all contaminants adequately, but VRmin did not, and VRmid did so only marginally. Air cleaning and local ventilation near strong sources both showed promise. Higher VRs increased indoor concentrations of outdoor air pollutants. Lowering VRs in big box stores in California from VRmax to VRmid would reduce total energy use by an estimated 6.6% and energy costs by 2.5%. Reducing the required VRs in California’s big box stores could reduce energy use and costs, but poses challenges for health and comfort of occupants. Source removal, air cleaning, and local ventilation may be needed at reduced VRs, and even at current recommended VRs. Also, alternative ventilation strategies taking climate and season into account in ventilation schedules may provide greater energy cost savings than constant ventilation rates, while improving IAQ.

  3. Quantile Regression Analysis of the Distributional Effects of Air Pollution on Blood Pressure, Heart Rate Variability, Blood Lipids, and Biomarkers of Inflammation in Elderly American Men: The Normative Aging Study

    PubMed Central

    Bind, Marie-Abele; Peters, Annette; Koutrakis, Petros; Coull, Brent; Vokonas, Pantel; Schwartz, Joel

    2016-01-01

    Background: Previous studies have observed associations between air pollution and heart disease. Susceptibility to air pollution effects has been examined mostly with a test of effect modification, but little evidence is available whether air pollution distorts cardiovascular risk factor distribution. Objectives: This paper aims to examine distributional and heterogeneous effects of air pollution on known cardiovascular biomarkers. Methods: A total of 1,112 men from the Normative Aging Study and residents of the greater Boston, Massachusetts, area with mean age of 69 years at baseline were included in this study during the period 1995–2013. We used quantile regression and random slope models to investigate distributional effects and heterogeneity in the traffic-related responses on blood pressure, heart rate variability, repolarization, lipids, and inflammation. We considered 28-day averaged exposure to particle number, PM2.5 black carbon, and PM2.5 mass concentrations (measured at a single monitor near the site of the study visits). Results: We observed some evidence suggesting distributional effects of traffic-related pollutants on systolic blood pressure, heart rate variability, corrected QT interval, low density lipoprotein (LDL) cholesterol, triglyceride, and intercellular adhesion molecule-1 (ICAM-1). For example, among participants with LDL cholesterol below 80 mg/dL, an interquartile range increase in PM2.5 black carbon exposure was associated with a 7-mg/dL (95% CI: 5, 10) increase in LDL cholesterol, while among subjects with LDL cholesterol levels close to 160 mg/dL, the same exposure was related to a 16-mg/dL (95% CI: 13, 20) increase in LDL cholesterol. We observed similar heterogeneous associations across low versus high percentiles of the LDL distribution for PM2.5 mass and particle number. Conclusions: These results suggest that air pollution distorts the distribution of cardiovascular risk factors, and that, for several outcomes, effects may be

  4. CHAPTER 11. DELIVERY AND DISTRIBUTION SYSTEMS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Water delivery through canals or pipelines usually implies that several farms must somehow share access to the water in terms of flow rate, duration of access, and the return time to access the flow again, called an irrigation schedule, which can be rigid or flexible regarding the rate, duration and...

  5. Causes of preterm delivery.

    PubMed

    Gravett, M G

    1984-10-01

    Although major advances have been made in both obstetric care of the high-risk patient and in neonatal care, prematurity and its consequences remain the major contributor to perinatal mortality. The identification of maternal or obstetric risk factors associated with preterm delivery has enhanced our ability to provide special obstetric care to gravidas at increased risk. The selective management of patients at increased risk for preterm delivery may ultimately reduce the incidence of preterm births. Maternal genital infections are also associated with preterm delivery. Further research is needed to explore the pathogenesis of preterm delivery associated with genital infections, since infections may represent a potentially preventable cause of prematurity.

  6. Changes in fat concentration of human milk during delivery by intermittent bolus and continuous mechanical pump infusion.

    PubMed

    Greer, F R; McCormick, A; Loker, J

    1984-11-01

    The changes in fat concentration and cumulative fat losses that occur during the delivery of human milk using two different continuous infusion systems were compared with the changes in fat concentration during simulated intermittent gavage or bolus feedings. With both mechanical pumps the largest cumulative fat losses and the greatest decreases in fat concentrations occurred at the slowest infusion rates. State of homogenization of the milk generally made little difference in the changes in fat concentration using the syringe pump, whereas homogenizing the milk increased the fat concentration significantly with the roller pump. With the syringe pump the positioning of the syringe tip (horizontal or vertical) made no difference in fat concentration at an infusion rate of 1 ml/hr, whereas at 4 and 7 ml/hr the fat concentration was increased significantly by keeping the syringe tip vertical. With either mechanical pump a large fat bolus was delivered during the eighth and final hour of infusion if the milk remaining in the tubing was recovered by using air infusion at the same infusion rate. Intermittent bolus delivery of human milk resulted in no significant loss of human milk fat, no changes in fat concentration, and no terminal delivery of a large fat load. Thus intermittent bolus feedings are preferred over continuous mechanical pump infusion systems for the delivery of human milk to low-birth-weight infants.

  7. Heat and mass transfer in a dissociated laminar boundary layer of air with consideration of the finite rate of chemical reaction

    NASA Technical Reports Server (NTRS)

    Oyegbesan, A. O.; Algermissen, J.

    1986-01-01

    A numerical investigation of heat and mass transfer in a dissociated laminar boundary layer of air on an isothermal flat plate is carried out for different degrees of cooling of the wall. A finite-difference chemical model is used to study elementary reactions involving NO2 and N2O. The analysis is based on equations of continuity, momentum, energy, conservation and state for the two-dimensional viscous flow of a reacting multicomponent mixtures. Attention is given to the effects of both catalyticity and noncatalyticity of the wall.

  8. Guidance on the relationship between the 15 percent rate-of-progress plans and other provisions of the Clean Air Act

    SciTech Connect

    Not Available

    1993-05-01

    The document focuses on the creditability of emissions reductions associated with programs covered by the Clean Air Act Amendments (CAAA) of 1990 toward the 15 percent volatile organic compound (VOC) emissions reduction requirements. The programs addressed in the document include those covered by Titles I through V of the CAAA. The programs addressed are: new source review (NSR), section 112 maximum achievable control technology (MACT) standards and early reductions, section 111 new source performance standards (NSPS), mobile source programs, Title IV nitrogen oxides (NOx) reductions, economic incentives programs (EIP's), and Title V operating permit programs.

  9. Effect of air-blast drying and the presence of protectants on the viability of yeast entrapped in calcium alginate beads with an aim to improve the survival rate.

    PubMed

    Kim, Dong-Hwan; Lee, Sae-Byuk; Park, Heui-Dong

    2017-01-01

    Five yeast strains, Saccharomyces cerevisiae D8, M12, and S13; Hanseniaspora uvarum S6; and Issatchenkia orientalis KMBL5774, isolated from Korean grapes, were entrapped in Ca-alginate beads, which are non-toxic, simple to use, and economical. Ca-alginate beads containing yeast cells were soaked in protective solutions, such as skim milk, saccharides, polyols, and nitrogen compounds, before air-blast drying to improve the yeast survival rate and storage ability. The results showed that both entrapment in Ca-alginate beads and soaking in protective agents favorably affected the survival of all strains. The microenvironment formed by the beads and protective agents can protect the yeast cells from harsh environmental conditions, such as low water (below 10 %). All the yeast strains entrapped in Ca-alginate beads showed greater than 80 % survival and less than 11 % water content after air-blast drying at 37 °C for 5 h. In addition, air-blast dried cells of S. cerevisiae D8, M12, S13; H. uvarum S6; and I. orientalis KMBL5774 entrapped in 2 % Ca-alginate beads and soaked in protective agents (10 % skim milk containing 10 % sucrose, 10 % raffinose, 10 % trehalose, 10 % trehalose, and 10 % glucose, respectively) after air-blast drying at 37 °C for 5 h showed 90, 87, 92, 90, and 87 % viability, respectively. All dried entrapped yeast cells showed survival rates of at least 51 % after storage at 4 °C for 3 months.

  10. Do perceived job insecurity and annoyance due to air and noise pollution predict incident self-rated poor health? A prospective analysis of independent and joint associations using a German national representative cohort study

    PubMed Central

    Riedel, Natalie; Loerbroks, Adrian; Bolte, Gabriele; Li, Jian

    2017-01-01

    Background Current economic and social change has contributed to increasing job insecurity and traffic-related pollution in residential areas. Both job insecurity and exposure to noise and air pollution are known determinants of population health and can concur in peoples' lives. This may hold true particularly for socially disadvantaged subpopulations. Nevertheless, the potential independent and joint links of those exposures to health have been rarely examined so far. We aimed to contribute to the scarce body of evidence. Methods Information on perceived job insecurity and exposures to noise and air pollution as expressed by annoyance as well as on self-rated health were gathered from 2 waves of the population-based German Socio-Economic Panel (2009 and 2011, N=6544). We performed multivariable Poisson regression to examine the independent and joint risk of poor health in 2011 by perceived job insecurity and annoyance due to noise and air pollution in 2009. Results After the 2-year follow-up in 2011, 571 (8.7%) participants rated their health as poor. The risk of reporting incident poor health was increased by roughly 40% in employees reporting high versus low perceived job insecurity and annoyance due to noise and air pollution, respectively. This risk increased when both exposures were present at higher levels (risk ratio=1.95 (1.49 to 2.55)). Conclusions Work-related and environmental exposures may accumulate and have a joint health impact. Elaboration on the link between occupational and residential exposures is warranted in the light of their concurrence and their implications for health inequities. PMID:28115332

  11. [Fetal macrosomia: mode of delivery].

    PubMed

    Tatarova, S; Popov, I; Khristova, P

    2004-01-01

    This study was provided among 1847 deliveries from January, 1 to December, 31, 2003. The aim of the study was to examine the correlation between antenatal diagnosis "fetal macrosomia" and the mode of delivery. We found that among the cases with birth weight > or = 4000 g and antenatal diagnosis "fetal macrosomia" the rate of cesarean section was fourfold higher than among the cases without such a diagnosis. There weren't statistically significant correlation between the cases with antenatal diagnosis "fetal macrosomia " and the cases with estimated birth weight < or = 3999g in reference to the mother's age and weight, parity, fundal height and abdominal circumference. There are insignificant differences between both of groups in reference to gestacional age and birth.

  12. Permeation enhancer strategies in transdermal drug delivery.

    PubMed

    Marwah, Harneet; Garg, Tarun; Goyal, Amit K; Rath, Goutam

    2016-01-01

    Today, ∼74% of drugs are taken orally and are not found to be as effective as desired. To improve such characteristics, transdermal drug delivery was brought to existence. This delivery system is capable of transporting the drug or macromolecules painlessly through skin into the blood circulation at fixed rate. Topical administration of therapeutic agents offers many advantages over conventional oral and invasive techniques of drug delivery. Several important advantages of transdermal drug delivery are prevention from hepatic first pass metabolism, enhancement of therapeutic efficiency and maintenance of steady plasma level of the drug. Human skin surface, as a site of drug application for both local and systemic effects, is the most eligible candidate available. New controlled transdermal drug delivery systems (TDDS) technologies (electrically-based, structure-based and velocity-based) have been developed and commercialized for the transdermal delivery of troublesome drugs. This review article covers most of the new active transport technologies involved in enhancing the transdermal permeation via effective drug delivery system.

  13. Formality in Rhetorical Delivery.

    ERIC Educational Resources Information Center

    Skopec, Eric Wm.

    Formality in rhetorical delivery can be defined as a complex variable that represents the speaker's efforts to invoke sociocultural rules of audience control through the nonverbal components of the delivery. This document describes some of the aspects of formality, outlines its significance in rhetorical contexts, and evaluates the concept in…

  14. [The moon and delivery].

    PubMed

    Romero Martínez, Jorge; Guerrero Guijo, Inmaculada; Artura Serrano, Antonio

    2004-11-01

    In different cultures and mythologies, the moon is related with fertility, pregnancy and delivery. Professional obstetricians also notice an increase in care demands on the days when the moon is full. Many studies have been made which try to correlate delivery processes to the phases of the moon with contradictory results. The authors plan to try to find any basis in fact which support these popular beliefs and to discover if lunar phases bear an influence on the distribution of deliveries. They carried out a descriptive transversal study on a total of 1715 unassisted deliveries over the course of ten complete lunar cycles. The authors have carried out a descriptive and inferential analysis, a one way ANOVA and a Kruskal Wallis test on their three data bases which are general, primipara and multipara in which they contemplated the total number of deliveries per phase, the mean of each phase, as well as the central day in each phase of the lunar cycle. The differences found in the distribution of deliveries over the four lunar phases, along with the comparison of the means and the comparison of the number of deliveries on the central day in each phase are not statistically significant. The different phases in the lunar cycle and especially the full moon do not appear to have any influence over the distribution of deliveries in this study.

  15. Designing Bioactive Delivery Systems for Tissue Regeneration

    PubMed Central

    Davis, Hillary E.

    2010-01-01

    The direct infusion of macromolecules into defect sites generally does not impart adequate physiological responses. Without the protection of delivery systems, inductive molecules may likely redistribute away from their desired locale and are vulnerable to degradation. In order to achieve efficacy, large doses supplied at interval time periods are necessary, often at great expense and ensuing detrimental side effects. The selection of a delivery system plays an important role in the rate of re-growth and functionality of regenerating tissue: not only do the release kinetics of inductive molecules and their consequent bioactivities need to be considered, but also how the delivery system interacts and integrates with its surrounding host environment. In the current review, we describe the means of release of macromolecules from hydrogels, polymeric microspheres, and porous scaffolds along with the selection and utilization of bioactive delivery systems in a variety of tissue-engineering strategies. PMID:20676773

  16. Novel biodegradable nanocarriers for enhanced drug delivery.

    PubMed

    Gagliardi, Mariacristina

    2016-12-01

    With the refinement of functional properties, the interest around biodegradable materials, in biorelated applications and, in particular, in their use as controlled drug-delivery systems, increased in the last decades. Biodegradable materials are an ideal platform to obtain nanoparticles for spatiotemporal controlled drug delivery for the in vivo administration, thanks to their biocompatibility, functionalizability, the control exerted on delivery rates and the complete degradation. Their application in systems for cancer treatment, brain and cardiovascular diseases is already a consolidated practice in research, while the bench-to-bedside translation is still late. This review aims at summarizing reported applications of biodegradable materials to obtain drug-delivery nanoparticles in the last few years, giving a complete overview of pros and cons related to degradable nanomedicaments.

  17. Protective supplied breathing air garment

    DOEpatents

    Childers, E.L.; Hortenau, E.F. von.

    1984-07-10

    A breathing air garment is disclosed for isolating a wearer from hostile environments containing toxins or irritants includes a suit and a separate head protective enclosure or hood engaging a suit collar in sealing attachment. The hood and suit collar are cylindrically shaped and dimensioned to enable the wearer to withdraw his hands from the suit sleeves to perform manual tasks within the hood interior. Breathing air is supplied from an external air line with an air delivery hose attached to the hood interior. The hose feeds air into an annular halo-like fiber-filled plenum having spaced discharge orifices attached to the hood top wall. A plurality of air exhaust/check valves located at the suit extremities cooperate with the hood air delivery system to provide a cooling flow of circulating air from the hood throughout the suit interior. A suit entry seal provided on the suit rear torso panel permits access into the suit and is sealed with an adhesive sealing flap. 17 figs.

  18. Protective supplied breathing air garment

    DOEpatents

    Childers, Edward L.; von Hortenau, Erik F.

    1984-07-10

    A breathing air garment for isolating a wearer from hostile environments containing toxins or irritants includes a suit and a separate head protective enclosure or hood engaging a suit collar in sealing attachment. The hood and suit collar are cylindrically shaped and dimensioned to enable the wearer to withdraw his hands from the suit sleeves to perform manual tasks within the hood interior. Breathing air is supplied from an external air line with an air delivery hose attached to the hood interior. The hose feeds air into an annular halo-like fiber-filled plenum having spaced discharge orifices attached to the hood top wall. A plurality of air exhaust/check valves located at the suit extremities cooperate with the hood air delivery system to provide a cooling flow of circulating air from the hood throughout the suit interior. A suit entry seal provided on the suit rear torso panel permits access into the suit and is sealed with an adhesive sealing flap.

  19. Elective Delivery Before 39 Weeks

    MedlinePlus

    ... Delivery, and Postpartum Care Elective Delivery Before 39 Weeks • What is a “medically indicated” delivery? • What is ... the baby grow and develop during the last weeks of pregnancy? • What are the risks for babies ...

  20. The Delivery of Developmental Mathematics: Course Redesign and Implementation at a Community College

    ERIC Educational Resources Information Center

    Westerfield, Mary Ann K.

    2013-01-01

    This research was undertaken to determine if the redesigned modular delivery method for developmental mathematics produced a higher sequence completion rate within a year as compared to the traditional lecture style delivery. Re-enrollment rates from fall to spring for the modularized delivery system were compared to the traditional delivery…

  1. Ultrafine particle removal and generation by portable air cleaners

    NASA Astrophysics Data System (ADS)

    Waring, Michael S.; Siegel, Jeffrey A.; Corsi, Richard L.

    Portable air cleaners can both remove and generate pollutants indoors. To investigate these phenomena, we conducted a two-phase investigation in a 14.75 m 3 stainless steel chamber. In the first phase, particle size-resolved (12.6-514 nm diameter) clean air delivery rates (CADR) and efficiencies were determined, as were ozone emission rates, for two high-efficiency particle arresting (HEPA) filters, one electrostatic precipitator with a fan, and two ion generators without fans. The two HEPA air cleaners had count average CADR (standard deviation) of 188 (30) and 324 (44) m 3 h -1; the electrostatic precipitator 284 (62) m 3 h -1; and the two ion generators 41 (11) and 35 (13) m 3 h -1. The electrostatic precipitator emitted ozone at a rate of 3.8±0.2 mg h -1, and the two ion generators 3.3±0.2 and 4.3±0.2 mg h -1. Ozone initiates reactions with certain unsaturated organic compounds that produce ultrafine and fine particles, carbonyls, other oxidized products, and free radicals. During the second phase, five different ion generators were operated separately in the presence of a plug-in liquid or solid air freshener, representing a strong terpene source. For air exchange rates of between 0.49 and 0.96 h -1, three ion generators acted as steady-state net particle generators in the entire measured range of 4.61-157 nm, and two generated particles in the range of approximately 10 to 39-55 nm. Terpene and aldehyde concentrations were also sampled for one ion generator, and concentrations of terpenes decreased and formaldehyde increased. Given these results, the pollutant removal benefits of ozone-generating air cleaners may be outweighed by the generation of indoor pollution.

  2. Ultrasound mediated nanoparticle drug delivery

    NASA Astrophysics Data System (ADS)

    Mullin, Lee B.

    . Ultrasound parameters are optimized to achieve maximum cell internalization of molecules and increased nanoparticle delivery to a cell layer on a coverslip. In-vivo studies demonstrate the possibility of using a lower dose of paclitaxel to slow tumor growth rates, increase doxorubicin concentration in tumor tissue, and enhance tumor delivery of fluorescent molecules through treatments that combine nanoparticles with ultrasound and microbubbles.

  3. Emission rates of particle number, mass and black carbon by the Los Angeles International Airport (LAX) and its impact on air quality in Los Angeles

    NASA Astrophysics Data System (ADS)

    Shirmohammadi, Farimah; Sowlat, Mohammad H.; Hasheminassab, Sina; Saffari, Arian; Ban-Weiss, George; Sioutas, Constantinos

    2017-02-01

    This study describes a series of air monitoring measurements of particle number (PN), black carbon (BC) and PM2.5 mass concentrations in the vicinity of the Los Angeles International Airport (LAX) (roughly 150 m downwind of the LAX's south runways) as well as on-road measurements of the aforementioned pollutants using a mobile platform on three major freeways (i.e., I-110, I-105, and I-405) during May-July 2016. All measurements were performed in the "impact zone" of LAX with the predominant westerly winds from coast to inland. The overall impact of aircraft emissions from the LAX airport and its facilities in comparison to vehicular emissions from freeways on air quality was evaluated on a local scale (i.e. areas in the vicinity of the airport). PN concentration was, on average, 4.1 ± 1.2 times greater at the LAX site than on the studied freeways. Particle number emission factors for takeoffs and landings were comparable, with average values of 8.69 ×1015 particles/kg fuel and 8.16 ×1015 particles/kg fuel, respectively, and indicated a nearly 4-fold statistically significant reduction in PN emission factors for takeoffs during the past decade. BC emission factors were 0.12 ± 0.02 and 0.11 ± 0.01 g/kg fuel during takeoffs and landings, respectively. Additionally, the mean PM2.5 emission factor values for takeoffs and landings were also comparable, with values of 0.38 ± 0.04 and 0.40 ± 0.05 g/kg fuel, respectively. Within the impact zone of the airport, an area of roughly 100 km2 downwind of the LAX, measurements indicated that the LAX daily contributions to PN, BC, and PM2.5 were approximately 11, 2.5, and 1.4 times greater than those from the three surrounding freeways. These results underscore the significance of the LAX airport as a major source of pollution within its zone of impact comparing to freeway emissions.

  4. A pulsed mode electrolytic drug delivery device

    NASA Astrophysics Data System (ADS)

    Yi, Ying; Buttner, Ulrich; Carreno, Armando A. A.; Conchouso, David; Foulds, Ian G.

    2015-10-01

    This paper reports the design of a proof-of-concept drug delivery device that is actuated using the bubbles formed during electrolysis. The device uses a platinum (Pt) coated nickel (Ni) metal foam and a solid drug in reservoir (SDR) approach to improve the device’s performance. This electrochemically-driven pump has many features that are unlike conventional drug delivery devices: it is capable of pumping periodically and being refilled automatically; it features drug release control; and it enables targeted delivery. Pt-coated metal foam is used as a catalytic reforming element, which reduces the period of each delivery cycle. Two methods were used for fabricating the Pt-coated metal: sputtering and electroplating. Of these two methods, the sputtered Pt-coated metal foam has a higher pumping rate; it also has a comparable recombination rate when compared to the electroplated Pt-coated metal foam. The only drawback of this catalytic reformer is that it consumes nickel scaffold. Considering long-term applications, the electroplated Pt metal foam was selected for drug delivery, where a controlled drug release rate of 2.2 μg  ±  0.3 μg per actuation pulse was achieved using 4 mW of power.

  5. Super Long Conductive Canal for Energy Delivery from Space

    SciTech Connect

    Apollonov, Victor V.

    2010-10-08

    The goal of the project is to accomplish a circle of experimental, engineering and technological works on creation of long conductive guide for energy delivery from space. High repetition rate pulse-periodic laser system and the most important components for the project realization will be presented. Optical system for long range energy delivery will be discussed in details. Some new applications of energy delivery system are highlighted.

  6. 77 FR 37034 - Oncor Electric Delivery Company LLC; Notice of Filing

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-20

    ...] Oncor Electric Delivery Company LLC; Notice of Filing Take notice that on May 16, 2012, Oncor Electric Delivery Company LLC submitted its tariff filing per 35.28(e): Oncor TFO Tariff Rate Changes...

  7. 77 FR 45599 - Oncor Electric Delivery Company LLC; Notice of Filing

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-01

    ...] Oncor Electric Delivery Company LLC; Notice of Filing Take notice that on June 19, 2012, Oncor Electric Delivery Company LLC submitted its tariff filing per 35.28(e): Oncor Tex-La Tariff Rate Changes...

  8. The Delivery System of Environmental Education at the Tertiary Level in the Asia-Pacific Region.

    ERIC Educational Resources Information Center

    Sato, Masahisa; Bhandari, Bishnu; Abe, Osamu

    2001-01-01

    Analyzes the delivery system of environmental education at the tertiary level in relation to higher education attendance rate. Describes the characteristics of the delivery system in countries such as China, India, Australia, Japan, South Korea, and Indonesia. (Author/MM)

  9. AIR QUALITY IMPACTS OF LIQUEFIED NATURAL GAS IN THE SOUTH COAST AIR BASIN OF CALIFORNIA

    SciTech Connect

    Carerras-Sospedra, Marc; Brouwer, Jack; Dabdub, Donald; Lunden, Melissa; Singer, Brett

    2011-07-01

    The effects of liquefied natural gas (LNG) on pollutant emission inventories and air quality in the South Coast Air Basin of California were evaluated using recent LNG emission measurements by Lawrence Berkeley National Laboratory and the Southern California Gas Company (SoCalGas), and with a state-of-the-art air quality model. Pollutant emissions can be affected by LNG owing to differences in composition and physical properties, including the Wobbe index, a measure of energy delivery rate. This analysis uses LNG distribution scenarios developed by modeling Southern California gas flows, including supplies from the LNG receiving terminal in Baja California, Mexico. Based on these scenarios, the projected penetratino of LNG in the South Coast Air Basin is expected to be limited. In addition, the increased Wobbe index of delivered gas (resulting from mixtures of LNG and conventional gas supplies) is expected to cause increases smaller than 0.05 percent in overall (area-wide) emissions of nitrogen oxides (NOx). BAsed on the photochemical state of the South Coast Air Basin, any increase in NOx is expected to cause an increase in the highest local ozone concentrations, and this is reflected in model results. However, the magnitude of the increase is well below the generally accepted accuracy of the model and would not be discernible with the existing monitoring network. Modeling of hypothetical scenarios indicates that discernible changes to ambient ozone and particulate matter concentrations would occur only at LNG distribution rates that are not achievable with current or planned infrastructure and with Wobbe index vlaues that exceed current gas quality tariffs. Results of these hypothetical scenarios are presented for consideration of any proposed substantial expansion of LNG supply infrastructure in Southern California.

  10. Noise Emission from Laboratory Air Blowers

    ERIC Educational Resources Information Center

    Rossing, Thomas D.; Windham, Betty

    1978-01-01

    Product noise ratings for a number of laboratory air blowers are reported and several recommendations for reducing laboratory noise from air blowers are given. Relevant noise ratings and methods for measuring noise emission of appliances are discussed. (BB)

  11. Intravenous drug delivery in neonates: lessons learnt.

    PubMed

    Sherwin, Catherine M T; Medlicott, Natalie J; Reith, David M; Broadbent, Roland S

    2014-06-01

    Intravenous drug administration presents a series of challenges that relate to the pathophysiology of the neonate and intravenous infusion systems in neonates. These challenges arise from slow intravenous flow rates, small drug volume, dead space volume and limitations on the flush volume in neonates. While there is a reasonable understanding of newborn pharmacokinetics, an appreciation of the substantial delay and variability in the rate of drug delivery from the intravenous line is often lacking. This can lead to difficulties in accurately determining the pharmacokinetic and pharmacodynamic relationship of drugs in the smallest patients. The physical variables that affect the passage of drugs through neonatal lines need to be further explored in order to improve our understanding of their impact on the delivery of drugs by this route in neonates. Through careful investigation, the underlying causes of delayed drug delivery may be identified and administration protocols can then be modified to ensure predictable, appropriate drug input kinetics.

  12. Breastfeeding After Cesarean Delivery

    MedlinePlus

    ... Breastfeeding Crying & Colic Diapers & Clothing Feeding & Nutrition Preemie Sleep Teething & Tooth Care Toddler Preschool Gradeschool Teen Young Adult Healthy Children > Ages & Stages > Baby > Breastfeeding > Breastfeeding After Cesarean Delivery Ages & Stages ...

  13. Transdermal delivery of proteins.

    PubMed

    Kalluri, Haripriya; Banga, Ajay K

    2011-03-01

    Transdermal delivery of peptides and proteins avoids the disadvantages associated with the invasive parenteral route of administration and other alternative routes such as the pulmonary and nasal routes. Since proteins have a large size and are hydrophilic in nature, they cannot permeate passively across the skin due to the stratum corneum which allows the transport of only small lipophilic drug molecules. Enhancement techniques such as chemical enhancers, iontophoresis, microneedles, electroporation, sonophoresis, thermal ablation, laser ablation, radiofrequency ablation and noninvasive jet injectors aid in the delivery of proteins by overcoming the skin barrier in different ways. In this review, these enhancement techniques that can enable the transdermal delivery of proteins are discussed, including a discussion of mechanisms, sterility requirements, and commercial development of products. Combination of enhancement techniques may result in a synergistic effect allowing increased protein delivery and these are also discussed.

  14. Delivery of twins.

    PubMed

    Hofmeyr, G J; Drakeley, A J

    1998-03-01

    The delivery of twins presents considerable challenges to the obstetric team, particularly in terms of decision-making, technical skills required and the need to respond quickly to changing circumstances. There is a serious lack of sound evidence upon which to base decisions concerning the method of delivery of twins. The trend towards the routine use of caesarean section is not supported by evidence of improved outcome for the infants, while maternal outcome is compromised. Specific circumstances that may have a bearing on the need for caesarean section include gestational age, presentation of the twins and chorionicity/amnionicity. Caesarean section does not eliminate the chance of fetal trauma during delivery, particularly for premature twins. The techniques of twin delivery, whether vaginal or by caesarean section, require thorough preparation for all possible eventualities, and skilled teamwork. Particular attention should be paid to emotional needs during labour, birth and afterwards, of the parents of twins.

  15. Delivery by Cesarean Section

    MedlinePlus

    ... Español Text Size Email Print Share Delivery by Cesarean Section Page Content Article Body More than one mother in three gives birth by Cesarean section in the United States (it is also called ...

  16. Project Delivery Methods.

    ERIC Educational Resources Information Center

    Dolan, Thomas G.

    2003-01-01

    Describes project delivery methods that are replacing the traditional Design/Bid/Build linear approach to the management, design, and construction of new facilities. These variations can enhance construction management and teamwork. (SLD)

  17. A laboratory simulation of toluene cleanup by air sparging of water-saturated sands.

    PubMed

    Peterson, J W; DeBoer, M J; Lake, K L

    2000-02-25

    Laboratory air sparging experiments were performed in narrow acrylic tanks to evaluate the cleanup of toluene in water-saturated sands. Air flow channels in the sediment were identified by way of a colorimetric visualization technique, which allowed pore water samples to be collected at a known horizontal distance from an air channel. Pore water was sampled at periodic intervals during sparging experiments and analyzed by gas chromatography to yield toluene concentration vs. time data. Results indicate that channelized air flow is effective in reducing toluene concentrations in the range of 36-3 ppm, within 2 to 5 days, at least up to 185 mm from an active air channel. While relatively rapid, these toluene reduction times are longer than previously published data, from similar type experiments. The discrepancy is likely a function of air delivery flow rate and proximity of sampling sites to active air channels. Data from the current investigation were used to attempt an estimate of effective diffusion coefficients (D*) for toluene in clean, well-characterized sands in which the concentration gradient was imposed by sparge air. Calculated D* values range from 2. 98x10(-8) m(2)/s to 5.74x10(-9) m(2)/s, and are significantly faster than previously published values of toluene diffusion in clay soils. However, the values are also slightly greater than diffusion coefficients for toluene in aqueous solutions, indicating that the calculations more likely estimate coefficients of hydrodynamic dispersion (D(L)).

  18. Self-cleaning feed distributing delivery device for glass melters

    SciTech Connect

    Mensink, D.L.

    1991-01-16

    This invention consists of a self cleaning, plug resistant, adjustable parameter feed distributing and delivery apparatus for a glass melter comprising a housing with a passage therethrough for a glass slurry, a cold finger within the passage for creating a dispersion patten of the slurry, a movable slotted tube for controlling the confluence of air propellant and slurry in the passage, and a plurality of ribs that extend through the slots in the slotted tube to urge the slurry forward if it becomes stuck or resists forward movement. Coolant passages in the housing and the cold finger maintain the slurry temperature below that of the melter plenum. The cold finger is axially movable to adjust the dispersion patten to the desired consistency. Other design features of size can be applied for use in situations requiring different parameters of patten, particle size, rate, feed consistencies. The device utilizes air as both a propellant and a surface cleansing mechanism. Other fluids may be used as propellants where process compatibility requires.

  19. Self-cleaning feed distributing delivery device for glass melters

    DOEpatents

    Mensink, Daniel L.

    1992-01-01

    A self cleaning, plug resistant, adjustable parameter feed distributing and delivery apparatus for a glass melter comprising a housing with a passage therethrough for a glass slurry, a cold finger within the passage for creating a dispersion pattern of the slurry, a movable slotted tube for controlling the confluence of air propellant and slurry in the passage, and a plurality of ribs that extend through the slots in the slotted tube to urge the slurry forward if it becomes stuck or resists forward movement. Coolant passages in the housing and the cold finger maintain the slurry temperature below that of the melter plenum. The cold finger is axially movable to adjust the dispersion pattern to the desired consistency. Other design features of size can be applied for use in situations requiring different parameters of pattern, particle size, rate, and feed consistencies. The device utilizes air as both a propellant and a surface cleansing mechanism. Other fluids may be used as propellants where process compatibility requires.

  20. Transpired Air Collectors - Ventilation Preheating

    SciTech Connect

    Christensen, C.

    2006-06-22

    Many commercial and industrial buildings have high ventilation rates. Although all that fresh air is great for indoor air quality, heating it can be very expensive. This short (2-page) fact sheet describes a technology available to use solar energy to preheat ventilation air and dramatically reduce utility bills.