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. PMID:19044163

  2. High Rate Data Delivery Thrust Area

    NASA Technical Reports Server (NTRS)

    Bhasin, Kul

    2000-01-01

    In this paper, a brief description of the high rate data delivery (HRDD) thrust area, its focus and current technical activities being carried out by NASA centers including JPL, academia and industry under this program is provided. The processes and methods being used to achieve active participation in this program are presented. The developments in space communication technologies, which will shape NASA enterprise missions in the 21 st. century, are highlighted.

  3. 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...

  4. 36 CFR 1002.17 - Aircraft and air delivery.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... the Federal Aviation Administration as found in 14 CFR chapter I. (e) The operation or use of... 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...

  5. 36 CFR 1002.17 - Aircraft and air delivery.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... the Federal Aviation Administration as found in 14 CFR chapter I. (e) The operation or use of... 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...

  6. 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. 2.17 Section 2.17 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR RESOURCE PROTECTION, PUBLIC USE AND RECREATION § 2.17 Aircraft and air delivery. (a) The following...

  7. 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. 2.17 Section 2.17 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR RESOURCE PROTECTION, PUBLIC USE AND RECREATION § 2.17 Aircraft and air delivery. (a) The following...

  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. 2.17 Section 2.17 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR RESOURCE PROTECTION, PUBLIC USE AND RECREATION § 2.17 Aircraft and air delivery. (a) The following...

  9. 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. 1002.17 Section 1002.17 Parks, Forests, and Public Property PRESIDIO TRUST RESOURCE PROTECTION, PUBLIC USE AND RECREATION § 1002.17 Aircraft and air delivery. (a) Delivering or retrieving a person or object by parachute, helicopter, or other...

  10. 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. 2.17 Section 2.17 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR RESOURCE PROTECTION, PUBLIC USE AND RECREATION § 2.17 Aircraft and air delivery. (a) The following...

  11. 36 CFR 1002.17 - Aircraft and air delivery.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... the Federal Aviation Administration as found in 14 CFR chapter I. (e) The operation or use of... 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...

  12. 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 just emerging,…

  13. Air kerma rate constants for radionuclides.

    PubMed

    Wasserman, H; Groenewald, W

    1988-01-01

    Conversion to SI units requires that the exposure rate constant which was usually quoted in R.h-1.mCi-1.cm2 be replaced by the air kerma rate constant with units m2.Gy.Bq-1.s-1. The conversion factor is derived and air kerma rate constants for 30 radionuclides used in nuclear medicine and brachytherapy are listed. A table for calculation of air kerma rates for other radionuclides is also given. To calculate absorbed dose to tissue, the air kerma rate has to be multiplied by approximately 1.1. A dose equivalent rate constant is thus listed which allows direct calculation of dose equivalent rate to soft tissue without resorting to exposure rate constants tabulated in the special units R.m2.mCi-1.h-1 which should no longer be used. PMID:3208786

  14. Air Controlman 1 & C: Rate Training Manual.

    ERIC Educational Resources Information Center

    Naval Training Command, Pensacola, FL.

    The manual is designed for use in preparing for advancement within the Navy Air Controlman rating, which designates a professional air traffic controller, unlike the more specialized center or tower controllers. However, minimum qualifications for the rating include completion of the Federal Aviation Administration (FAA) written examination for…

  15. 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

  16. 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

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

    PubMed

    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

  18. 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

  19. Operative delivery rates following induction of labour for obstetric cholestasis

    PubMed Central

    Webster, Jessica R; Chappell, Lucy; Cheng, Floria; Breeze, Andrew C G; Lucas, Nuala; Plaat, Felicity; Williamson, Catherine

    2011-01-01

    The aim of this study was to determine whether women induced for obstetric cholestasis (OC) have increased rates of operative delivery compared with women without OC who are induced. This retrospective case-control study included 64 women with OC (singleton pregnancies), who had labour induced compared with two control groups (matched for parity and gestational week at delivery). The majority of women were induced at 37 weeks. We found no significant increase in the rate of operative or assisted delivery in OC cases compared with either control group. Women with OC who are induced between 36 and 40 weeks gestation do not have increased rates of assisted or operative delivery compared with induced controls.

  20. Operative delivery rates following induction of labour for obstetric cholestasis.

    PubMed

    Webster, Jessica R; Chappell, Lucy; Cheng, Floria; Breeze, Andrew C G; Lucas, Nuala; Plaat, Felicity; Williamson, Catherine

    2011-06-01

    The aim of this study was to determine whether women induced for obstetric cholestasis (OC) have increased rates of operative delivery compared with women without OC who are induced. This retrospective case-control study included 64 women with OC (singleton pregnancies), who had labour induced compared with two control groups (matched for parity and gestational week at delivery). The majority of women were induced at 37 weeks. We found no significant increase in the rate of operative or assisted delivery in OC cases compared with either control group. Women with OC who are induced between 36 and 40 weeks gestation do not have increased rates of assisted or operative delivery compared with induced controls. PMID:27582856

  1. Efficient delivery techniques for variable-bit-rate multimedia

    NASA Astrophysics Data System (ADS)

    Zhao, Yanping; Eager, Derek L.; Vernon, Mary K.

    2001-12-01

    Two key technologies enabling scalable on-demand delivery of stored multimedia content are work-ahead smoothing and multicast delivery. Work-ahead smoothing reduces the burstiness of variable bit rate streams, simplifying server and network resource allocation. Recent multicast delivery techniques such as patching or bandwidth skimming serve clients that request the same content close together in time with (partially) shared multicasts, greatly reducing required server bandwidth. Although previous studies of work-ahead smoothing have generally assumed very limited client buffer space, in a number of contexts of current interest (such as systems that have significant settop storage), it becomes feasible to fully smooth variable bit rate content. We quantify the start-up delay and settop storage requirements of full smoothing for a number of sample variable bit rate objects. We then evaluate a fundamental conflict between aggressive smoothing and the new multicast delivery techniques. Work-ahead smoothing requires sending data for high rate portions of an object earlier than it is needed for playback, while multicast techniques yield their greatest benefit when data is delivered within each stream as late as possible so that more clients can share reception of that data. A new multicast delivery technique is proposed that can accommodate aggressive smoothing with increased efficiency in comparison to previous techniques, particularly for high request rates.

  2. 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.

  3. Food intake rate and delivery strategy in aquaculture

    NASA Astrophysics Data System (ADS)

    You, Kui; Ma, Caihua; Gao, Huiwang; Li, Fengqi; Zhang, Meizhao; Qiu, Yantao; Wang, Bo

    2008-08-01

    In aquaculture, it is important to estimate in advance how much food cultured animals would take. The rate of food consumption by cultured animals to available food amount is defined as the food intake rate (FIR) in this paper. To some extents, FIR reflects the quality of food, the health of cultured animals and the delivery efficiency. In practice, it is difficult to estimate in advance the accurate quantity of food that cultured animal needs. Usually, food is provided more than the need by animals, causing excess food that may pollute water and environment. Our experiments in past years show that FIR at 80% is recommended.

  4. 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...

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

    MedlinePlus

    ... Cesarean delivery rates at 38 weeks declined for all maternal age groups, but increased at 39 weeks. ... Cesarean delivery rates at 38 weeks declined for all racial and ethnic groups, but rose at 39 ...

  6. Road Sediment Production and Delivery: Processes, Rates, and Possible Improvements

    NASA Astrophysics Data System (ADS)

    MacDonald, Lee; Ramos-Scharron, Carlos; Coe, Drew; Stafford, Alexander; Welsh, Matthew; Korte, Abby; Libohova, Zamir; Brown, Ethan; James, Cajun

    2013-04-01

    Unpaved roads are increasingly recognized as one of the largest sources of anthropogenic sediment in forested areas. For nearly 20 years we have been studying road surface erosion and sediment delivery across widely varying environments in California, Colorado, and the Caribbean. The objectives of this paper are to: 1) compare road sediment production and delivery rates across different environments; 2) summarize the primary controls on road surface erosion and sediment delivery; 3) estimate the relative contribution of roads to watershed-scale sediment yields; and 4) suggest management practices to minimize road sediment production and delivery. In our studies segment-scale sediment production is measured with sediment fences, while detailed road surveys are used to assess road-stream connectivity and estimating the contribution of roads to watershed-scale sediment yields. Road-induced mass movements are not included here. Our mean road sediment production rates range from 0.1 kg m-2 yr-1 in snow-dominated areas in California's Sierra Nevada to 3.5 kg m-2 yr-1 in Colorado and 7.4 kg m-2 yr-1 on St. John in the Caribbean. First-order controls on road sediment production are the amount and type of precipitation, road gradient, road surface area, and surface cover, although geology and soil type also can be important. Higher traffic levels can greatly increase road sediment production by reducing the amount of surface cover, increasing the supply of fine sediment, and increasing the propensity for rilling, particularly during wet weather. Applying gravel can reduce road sediment production by a factor of 2-8 times by largely eliminating rainsplash and reducing rilling. Grading will at least double road sediment production by increasing the supply of easily erodible fine particles. The percent of road length connected to streams also varies widely. In California only 3% of the road length was connected in a snow-dominated area as opposed to 30% in a nearby rain

  7. Current Problems and Issues in Air Freight Rates

    NASA Technical Reports Server (NTRS)

    Stout, A. R.

    1972-01-01

    Actions of the Civil Aeronautics Board in determining air freight rates are discussed. The tariff filings by domestic airlines for making basic changes in domestic fares and rates are reported. The roles of the carriers and the Civil Aeronautics Board in establishing freight rates are defined. Specific examples of areas of controversy in establishing freight rates are included. Methods for improving the air cargo and freight rate situation are proposed.

  8. 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...

  9. RESIDENTIAL AIR EXCHANGE RATES FOR USE IN INDOOR AIR AND EXPOSURE MODELING STUDIES

    EPA Science Inventory

    Data on air exchange rates are important inputs to indoor air quality models. ndoor air models, in turn, are incorporated into the structure of total human exposure models. ragmentary data on residential ventilation rates are available in various governmental reports, journal art...

  10. 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, LIBRARY OF CONGRESS COPYRIGHT ARBITRATION ROYALTY PANEL RULES AND PROCEDURES ADJUSTMENT OF ROYALTY PAYABLE... digital phonorecord deliveries. The royalty rate for digital phonorecord deliveries where the...

  11. 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, LIBRARY OF CONGRESS COPYRIGHT ARBITRATION ROYALTY PANEL RULES AND PROCEDURES ADJUSTMENT OF ROYALTY PAYABLE... digital phonorecord deliveries. The royalty rate for digital phonorecord deliveries where the...

  12. 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, LIBRARY OF CONGRESS COPYRIGHT ARBITRATION ROYALTY PANEL RULES AND PROCEDURES ADJUSTMENT OF ROYALTY PAYABLE... digital phonorecord deliveries. The royalty rate for digital phonorecord deliveries where the...

  13. 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, LIBRARY OF CONGRESS COPYRIGHT ARBITRATION ROYALTY PANEL RULES AND PROCEDURES ADJUSTMENT OF ROYALTY PAYABLE... digital phonorecord deliveries. The royalty rate for digital phonorecord deliveries where the...

  14. 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

  15. Acute Air Pollution Exposure and Blood Pressure at Delivery Among Women With and Without Hypertension

    PubMed Central

    Männistö, Tuija; Liu, Danping; Leishear, Kira; Sherman, Seth; Laughon, S. Katherine

    2015-01-01

    BACKGROUND Chronic air pollution exposure increases risk for hypertensive disorders of pregnancy, but the effect of acute air pollution exposure on blood pressure during pregnancy is less well known. METHODS We studied 151,276 singleton term deliveries from the Consortium on Safe Labor (2002–2008) with clinical blood pressure measured at admission to labor/delivery and diagnoses of hypertensive disorders collected from electronic medical records and hospital discharge summaries. Air pollution exposures were estimated for the admission hour and the 4 hours preceding admission using a modified version of the Community Multiscale Air Quality models and observed air monitoring data. Blood pressure was categorized as normal; high normal; and mild, moderate, or severe hypertension based on pregnancy cut points. Adjusted ordinal logistic regression estimated the odds of women having a higher admission blood pressure category as a function of air pollutant, hypertensive disorders, and their interaction effect. RESULTS Odds of high blood pressure at admission to labor/delivery were increased in normotensive women after exposure to nitrogen oxides (by 0.2%/5 units), sulfur dioxide (by 0.3%/1 unit), carbon monoxide and several air toxics (by 3%–4%/high exposure). The effects were often similar or stronger among women with gestational hypertension and preeclampsia. Exposure to particulate matter <10 μm increased odds of high blood pressure in women with preeclampsia by 3%/5 units. CONCLUSIONS Air pollution can influence admission blood pressure in term deliveries and may increase likelihood of preeclampsia screening at delivery admission. PMID:24795401

  16. 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.

  17. Delivery Rate Affects Uptake of a Fluorescent Glucose Analog in Murine Metastatic Breast Cancer

    PubMed Central

    Rajaram, Narasimhan; Frees, Amy E.; Fontanella, Andrew N.; Zhong, Jim; Hansen, Katherine; Dewhirst, Mark W.; Ramanujam, Nirmala

    2013-01-01

    We demonstrate an optical strategy using intravital microscopy of dorsal skin flap window chamber models to image glucose uptake and vascular oxygenation in vivo. Glucose uptake was imaged using a fluorescent glucose analog, 2-[N-(7-nitrobenz-2-oxa-1,3-diaxol-4-yl)amino]-2-deoxyglucose (2-NBDG). SO2 was imaged using the differential absorption properties of oxygenated [HbO2] and deoxygenated hemoglobin [dHb]. This study was carried out on two sibling murine mammary adenocarcinoma lines, 4T1 and 4T07. 2-NBDG uptake in the 4T1 tumors was lowest when rates of delivery and clearance were lowest, indicating perfusion-limited uptake in poorly oxygenated tumor regions. For increasing rates of delivery that were still lower than the glucose consumption rate (as measured in vitro), both 2-NBDG uptake and the clearance rate from the tumor increased. When the rate of delivery of 2-NBDG exceeded the glucose consumption rate, 2-NBDG uptake decreased with any further increase in rate of delivery, but the clearance rate continued to increase. This inflection point was not observed in the 4T07 tumors due to an absence of low delivery rates close to the glucose consumption rate. In the 4T07 tumors, 2-NBDG uptake increased with increasing rates of delivery at low rates of clearance. Our results demonstrate that 2-NBDG uptake in tumors is influenced by the rates of delivery and clearance of the tracer. The rates of delivery and clearance are, in turn, dependent on vascular oxygenation of the tumors. Knowledge of the kinetics of tracer uptake as well as vascular oxygenation is essential to make an informed assessment of glucose demand of a tumor. PMID:24204635

  18. Greenhouse Gas Growth Rates from AIRS Hyperspectral Radiance Time Series

    NASA Astrophysics Data System (ADS)

    Strow, L. L.; Desouza-Machado, S. G.; Hannon, S.; Imbiriba, B.; Schou, P.

    2009-12-01

    The AIRS seven year hyperspectral radiance record provides an ideal platform for measurings growth rates of infrared active minor gases, especially carbon dioxide and methane. The largest changes in CLARREO radiances will likely be due to increasing carbon dioxide and other greenhouse gases. We have produced a 5+ year record of almost cloud-free AIRS radiances, from which we have derived the radiance anomaly and linear time rate of change. The source of these radiances are the L1b radiances corrected for small frequency drifts. Growth rates of carbon dioxide, nitrous oxide, methane, ozone, and CFC11 are simultaneously derived from zonal averages of these radiance rates for tropics, and mid-latitude northern and southern hemispheres. The effective linear rate of change of ~5 layers of water vapor and temperature, plus the surface temperature are also simultaneously derived with the minor gas rates. No model data or prior is needed and more than 1000 channels are used in the fit. Sampling issues may preclude the use of the mid-latitude temperature and water vapor rates for climate analysis, but possibly not for the tropics. The resulting greenhouse gas growth rates agree very well with in-situ measurements, which suggests high radiometric stability for AIRS. Radiance intercomparisons for climate analysis between IASI and AIRS will also be presented.

  19. Relationship between air exchange rate and indoor VOC levels

    SciTech Connect

    Otson, R.; Williams, D.T.; Fellin, P.

    1998-12-31

    It is often assumed that the air quality is better in leaky than in airtight buildings. To test this anecdotal hypothesis, data from two Canadian surveys were examined. Indoor measurements of 28 volatile organic compounds (VOCs) were made by means of a passive sampling method during the 24 to 48 h study periods in both studies, and air exchange rates were determined by the perfluorocarbon tracer approach. The air exchange rates ranged between about 0.1 to 2.5 air changes per hour in 54 test homes in the Greater Toronto Area (GTA). Other information on building age and construction, renovation activities and occupant activities that potentially influenced indoor VOC concentrations in the homes was collected by means of a questionnaire. The statistical relationships between the concentrations of VOCs and air exchange were determined. Correlation coefficients between the airborne concentrations of each VOC and the air exchange rates for the homes were all < 0.1 indicating that the relationship between the air exchange and indoor VOC concentrations is tenuous. Since the questionnaire responses did not provide quantitative estimates of indoor emissions, a quantitative correlation between responses and indoor concentrations could not be established nor was a consistent pattern evident between these responses and the occurrence of high indoor concentrations. The lack of definitive quantitative relationships is not surprising considering the complexity of indoor environments, the lack of a detailed inventory of indoor sources and their emission rates and a lack of information or understanding of indoor sinks. The findings, on the effect of air exchange rates and the value of questionnaires in studies on indoor VOCs are consistent with findings in other similar studies.

  20. Residential air exchange rates for use in indoor air and exposure modeling studies.

    PubMed

    Pandian, M D; Ott, W R; Behar, J V

    1993-01-01

    Data on air exchange rates are important inputs to indoor air quality models. Indoor air models, in turn, are incorporated into the structure of total human exposure models. Fragmentary data on residential ventilation rates are available in various governmental reports, journal articles, and contractor reports. Most of the published papers present data on only a few homes to answer very specialized questions, and none of these publications summarize the ventilation rates of a large population of homes across the United States. Brookhaven National Laboratory (BNL) has conducted more than 4000 residential perfluorocarbon tracer (PFT) measurements and brought them together into a large data base from about 100 studies in the United States and elsewhere. This paper analyzes the BNL PFT data base to generate frequency distributions and summary statistics for different regions of the United States, different seasons, and different levels within the homes. The data analyses suggest that residential ventilation rates are similar in the northeastern and northwestern states but higher in the southwestern states. Winter and fall ventilation rates are similar, but the rates are slightly higher in spring, and much higher in summer. Multi-level residences have higher air exchange rates than single-level residences. Although the BNL data are not a representative sample of homes in the United States, these analyses give insight into the range of air exchange rates found in the United States under a great variety of conditions and are intended for use by developers of models of indoor air quality and total human exposure. PMID:8173341

  1. 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 OFFICE, LIBRARY OF CONGRESS COPYRIGHT ARBITRATION ROYALTY PANEL RULES AND PROCEDURES ADJUSTMENT OF... for incidental digital phonorecord deliveries. The royalty rate for digital phonorecord...

  2. 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.

  3. 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.

  4. 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.

  5. 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

  6. Ventilating-air change rate versus particulate contaminant spread

    SciTech Connect

    Langer, G.; Deitesfeld, C.A.

    1987-11-13

    This study provides information on the spread of particulate contamination from glovebox leaks in plutonium manufacturing facilities, with emphasis on the effect of ventilating-air change rate on contaminated spread. A new, very sensitive aerosol tracer technique was developed to simulate plutonium aerosol leaks and its dispersion in a room. The tracer, a submicron aerosol of phloroglucinol, does not interfere with work activity and is detected by its ability to form ice crystals in a supercooled cloud. This technique was applied in Buildings 371 and 707 plutonium production areas. The tracer spread throughout the rooms in a few minutes and reached its equilibrium concentration in 10 to 25 min. Also, to clear the room of all tracer took about the same time. In one room, tracer concentration decreased proportionally to the air change rate, while in the second one, air change rate had no effect. This points out the need for air velocity data. Also, future work must include simultaneous particle concentration measurements at several points. 4 refs., 9 figs., 2 tabs.

  7. 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.

  8. 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.

  9. 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.

  10. 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. PMID:23715084

  11. 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. PMID:25953689

  12. 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. PMID:26120571

  13. The Effects of Air Pollution on Ischemic Stroke Admission Rate

    PubMed Central

    Alimohammadi, Hossein; Fakhri, Sara; Derakhshanfar, Hojjat; Hosseini-Zijoud, Seyed-Mostafa; Safari, Saeed

    2016-01-01

    The present study aimed to determine the relationship between the level of air pollutants and the rate of ischemic stroke (IS) admissions to hospitals. In this retrospective cross-sectional study, stroke admissions (January-March 2012 and 2013) to an emergency department and air pollution and meteorological data were gathered. The relationship between air pollutant levels and hospital admission rates were evaluated using the generalize additive model. In all 379 patients with IS were referred to the hospital (52.5% male; mean age 68.2±13.3 years). Both transient (p<0.001) and long-term (p<0.001) rises in CO level increases the risk of IS. Increased weekly (p<0.001) and monthly (p<0.001) average O3 levels amplifies this risk, while a transient increase in NO2 (p<0.001) and SO2 (p<0.001) levels has the same effect. Long-term changes in PM10 (p<0.001) and PM2.5 (p<0.001) also increase the risk of IS. The findings showed that the level of air pollutants directly correlates with the number of stroke admissions to the emergency department. PMID:26866000

  14. The Effects of Air Pollution on Ischemic Stroke Admission Rate.

    PubMed

    Alimohammadi, Hossein; Fakhri, Sara; Derakhshanfar, Hojjat; Hosseini-Zijoud, Seyed-Mostafa; Safari, Saeed; Hatamabadi, Hamid Reza

    2016-01-01

    The present study aimed to determine the relationship between the level of air pollutants and the rate of ischemic stroke (IS) admissions to hospitals. In this retrospective cross-sectional study, stroke admissions (January-March 2012 and 2013) to an emergency department and air pollution and meteorological data were gathered. The relationship between air pollutant levels and hospital admission rates were evaluated using the generalize additive model. In all 379 patients with IS were referred to the hospital (52.5% male; mean age 68.2±13.3 years). Both transient (p<0.001) and long-term (p<0.001) rises in CO level increases the risk of IS. Increased weekly (p<0.001) and monthly (p<0.001) average O3 levels amplifies this risk, while a transient increase in NO2 (p<0.001) and SO2 (p<0.001) levels has the same effect. Long-term changes in PM10 (p<0.001) and PM2.5 (p<0.001) also increase the risk of IS. The findings showed that the level of air pollutants directly correlates with the number of stroke admissions to the emergency department. PMID:26866000

  15. 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…

  16. 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.

  17. 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)

  18. The air-kerma rate constant of 192Ir.

    PubMed

    Ninković, M M; Raiĉevìć, J J

    1993-01-01

    The air-kerma rate constant gamma delta (and its precursors), as one of the basic radiation characteristics of 192Ir, was determined by many authors. Analysis of accessible data on this quantity led us to the conclusion that published data strongly disagree. That is the reason we calculated this quantity on the basis of our and many other authors' gamma-ray spectral data and the latest data for mass energy-transfer coefficients for air. In this way, a value was obtained for gamma delta of 30.0 +/- 0.9 a Gy m2 s-1 Bq-1 for an unshielded 192Ir source and 27.8 +/- 0.9 a Gy m2s -1Bq-1 for a standard packaged radioactive source taking into account attenuation of gamma rays in the platinum source wall. PMID:8416220

  19. 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

    2011-04-01

    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. PMID:21364260

  20. Expected rates with mini-arrays for air showers

    NASA Technical Reports Server (NTRS)

    Hazen, W. E.

    1985-01-01

    As a guide in the design of mini-arrays used to exploit the Linsley effect in the study of air showers, it is useful to calculate the expected rates. The results can aid in the choice of detectors and their placement or in predicting the utility of existing detector systems. Furthermore, the potential of the method can be appraised for the study of large showers. Specifically, we treat the case of a mini-array of dimensions small enough compared to the distance of axes of showers of interest so that it can be considered a point detector. The input information is taken from the many previous studies of air showers by other groups. The calculations will give: (1) the expected integral rate, F(sigma, rho), for disk thickness, sigma, or rise time, t sub 1/2, with local particle density, rho, as a parameter; (2) the effective detection area A(N) with sigma (min) and rho (min) and rho (min) as parameters; (3) the expected rate of collection of data F sub L (N) versus shower size, N.

  1. 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).

  2. 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 phonorecord deliveries in general. 255.5 Section 255.5 Patents, Trademarks, and Copyrights U.S. COPYRIGHT OFFICE, LIBRARY OF CONGRESS COPYRIGHT ARBITRATION ROYALTY PANEL RULES AND PROCEDURES ADJUSTMENT...

  3. 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 phonorecord deliveries in general. 255.5 Section 255.5 Patents, Trademarks, and Copyrights COPYRIGHT OFFICE, LIBRARY OF CONGRESS COPYRIGHT ARBITRATION ROYALTY PANEL RULES AND PROCEDURES ADJUSTMENT OF ROYALTY...

  4. 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 phonorecord deliveries in general. 255.5 Section 255.5 Patents, Trademarks, and Copyrights COPYRIGHT OFFICE, LIBRARY OF CONGRESS COPYRIGHT ARBITRATION ROYALTY PANEL RULES AND PROCEDURES ADJUSTMENT OF ROYALTY...

  5. 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 phonorecord deliveries in general. 255.5 Section 255.5 Patents, Trademarks, and Copyrights COPYRIGHT OFFICE, LIBRARY OF CONGRESS COPYRIGHT ARBITRATION ROYALTY PANEL RULES AND PROCEDURES ADJUSTMENT OF ROYALTY...

  6. 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.

  7. 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

  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. 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.

  10. 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.

  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. Primary Air-Liquid Interface Culture of Nasal Epithelium for Nasal Drug Delivery.

    PubMed

    Ong, Hui Xin; Jackson, Claire L; Cole, Janice L; Lackie, Peter M; Traini, Daniela; Young, Paul M; Lucas, Jane; Conway, Joy

    2016-07-01

    Nasal drug administration is a promising alternative to oral and parenteral administration for both local and systemic delivery of drugs. The benefits include its noninvasive nature, rapid absorption, and circumvention of first pass metabolism. Hence, the use of an in vitro model using human primary nasal epithelial cells could be key to understanding important functions and parameters of the respiratory epithelium. This model will enable investigators to address important and original research questions using a biologically relevant in vitro platform that mimics the in vivo nasal epithelial physiology. The purpose of this study was to establish, systematically characterize, and validate the use of a primary human nasal epithelium model cultured at the air-liquid interface for the study of inflammatory responses and drug transport and to simultaneously quantify drug effects on ciliary activity. PMID:27223825

  14. Impact of Surface Curvature on Dose Delivery in Intraoperative High-Dose-Rate Brachytherapy

    SciTech Connect

    Oh, Moonseong Wang Zhou; Malhotra, Harish K.; Jaggernauth, Wainwright; Podgorsak, Matthew B.

    2009-04-01

    In intraoperative high-dose-rate (IOHDR) brachytherapy, a 2-dimensional (2D) geometry is typically used for treatment planning. The assumption of planar geometry may cause serious errors in dose delivery for target surfaces that are, in reality, curved. A study to evaluate the magnitude of these errors in clinical practice was undertaken. Cylindrical phantoms with 6 radii (range: 1.35-12.5 cm) were used to simulate curved treatment geometries. Treatment plans were developed for various planar geometries and were delivered to the cylindrical phantoms using catheters inserted into Freiburg applicators of varying dimension. Dose distributions were measured using radiographic film. In comparison to the treatment plan (for a planar geometry), the doses delivered to prescription points were higher on the concave side of the geometry, up to 15% for the phantom with the smallest radius. On the convex side of the applicator, delivered doses were up to 10% lower for small treated areas ({<=} 5 catheters) but, interestingly, the dose error was negligible for large treated areas (>5 catheters). Our measurements have shown inaccuracy in dose delivery when the original planar treatment plan is delivered with a curved applicator. Dose delivery errors arising from the use of planar treatment plans with curved applicators may be significant.

  15. Increased risk of preterm delivery in areas with air pollution from a petroleum refinery plant in Taiwan.

    PubMed

    Lin, M C; Chiu, H F; Yu, H S; Tsai, S S; Cheng, B H; Wu, T N; Sung, F C; Yang, C Y

    2001-12-21

    The petrochemical and petroleum industries are among the main sources of industrial air pollution in Taiwan. Data in this study concern outdoor air pollution and the health of individuals living in communities in close proximity to a petroleum refinery plant. The prevalence of delivery of preterm birth infants was significantly higher in mothers living in a petroleum refinery area compared to controls in Taiwan. After controlling for several possible confounders (including maternal age, season, marital status, maternal education, and infant sex), the adjusted odds ratio was 1.41 (95% CI = 1.08-1.82) for delivery of preterm infants in the polluted region. Data support the view that air pollution can affect the outcome of pregnancy. PMID:11766170

  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. Estimation of uncertainty in tracer gas measurement of air change rates.

    PubMed

    Iizuka, Atsushi; Okuizumi, Yumiko; Yanagisawa, Yukio

    2010-12-01

    Simple and economical measurement of air change rates can be achieved with a passive-type tracer gas doser and sampler. However, this is made more complex by the fact many buildings are not a single fully mixed zone. This means many measurements are required to obtain information on ventilation conditions. In this study, we evaluated the uncertainty of tracer gas measurement of air change rate in n completely mixed zones. A single measurement with one tracer gas could be used to simply estimate the air change rate when n = 2. Accurate air change rates could not be obtained for n ≥ 2 due to a lack of information. However, the proposed method can be used to estimate an air change rate with an accuracy of <33%. Using this method, overestimation of air change rate can be avoided. The proposed estimation method will be useful in practical ventilation measurements. PMID:21318005

  19. HAZARDOUS AIR POLLUTANTS: WET REMOVAL RATES AND MECHANISMS

    EPA Science Inventory

    Fourteen hazardous organic air pollutants were evaluated for their potentials to be wet deposited by precipitation scavenging. This effort included a survey of solubilities (Henry's Law constants) in the literature, measurement of solubilities of three selected species, developme...

  20. REFINED PHOTOLYSIS RATES FOR ADVANCED AIR QUALITY MODELING SYSTEM

    EPA Science Inventory

    Accurate modeling of photochemistry is critical and fundamental to reducing the uncertainty in air quality model predictions. lmost all chemical reactions in the atmosphere are initiated by the photodissociation of a number of trace gases. irect measure of this photodissociation ...

  1. Investigation of pulsed low dose rate radiotherapy using dynamic arc delivery techniques

    NASA Astrophysics Data System (ADS)

    Ma, C.-M.; Lin, M. H.; Dai, X. F.; Koren, Sion; Klayton, T.; Wang, L.; Li, J. S.; Chen, L.; Price, R. A.

    2012-07-01

    There has been no consensus standard of care to treat recurrent cancer patients who have previously been irradiated. Pulsed low dose rate (PLDR) external beam radiotherapy has the potential to reduce normal tissue toxicities while still providing significant tumor control for recurrent cancers. This work investigates the dosimetry feasibility of PLDR treatment using dynamic arc delivery techniques. Five treatment sites were investigated in this study including breast, pancreas, prostate, head and neck, and lung. Dynamic arc plans were generated using the Varian Eclipse system and the RapidArc delivery technique with 6 and 10 MV photon beams. Each RapidArc plan consisted of two full arcs and the plan was delivered five times to achieve a daily dose of 200 cGy. The dosimetry requirement was to deliver approximately 20 cGy/arc with a 3 min interval to achieve an effective dose rate of 6.7 cGy min-1. Monte Carlo simulations were performed to calculate the actual dose delivered to the planning target volume (PTV) per arc taking into account beam attenuation/scattering and intensity modulation. The maximum, minimum and mean doses to the PTV were analyzed together with the dose volume histograms and isodose distributions. The dose delivery for the five plans was validated using solid water phantoms inserted with an ionization chamber and film, and a cylindrical detector array. Two intensity-modulated arcs were used to efficiently deliver the PLDR plans that provided conformal dose distributions for treating complex recurrent cancers. For the five treatment sites, the mean PTV dose ranged from 18.9 to 22.6 cGy/arc. For breast, the minimum and maximum PTV dose was 8.3 and 35.2 cGy/arc, respectively. The PTV dose varied between 12.9 and 27.5 cGy/arc for pancreas, 12.6 and 28.3 cGy/arc for prostate, 12.1 and 30.4 cGy/arc for H&N, and 16.2 and 27.6 cGy/arc for lung. Advanced radiation therapy can provide superior target coverage and normal tissue sparing for PLDR

  2. Development of Strategies to Reduce Cesarean Delivery Rates in Iran 2012–2014: A Mixed Methods Study

    PubMed Central

    Lotfi, Razieh; Tehrani, Fahimeh Ramezani; Dovom, Marzieh Rostami; Torkestani, Farahnaz; Abedini, Mehrandokht; Sajedinejad, Sima

    2014-01-01

    Background: With the change in population policy from birth control toward encouraging birth and population growth in Iran, repeated cesarean deliveries as a main reason of cesarean section are associated with more potential adverse consequences. The aim of this research was to explore effective strategies to reduce cesarean delivery rates in Iran. Methods: A mixed methodological study was designed and implemented. First, using a qualitative approach, concepts and influencing factors of increased cesarean delivery were explored. Based on the findings of this phase of the study, a questionnaire including the proposed strategies to reduce cesarean delivery was developed. Then in a quantitative phase, the questionnaire was assessed by key informants from across the country and evaluated to obtain more effective strategies to reduce cesarean delivery. Ten participants in the qualitative study included policy makers from the Ministry of Health, obstetricians, midwives and anthropologists. In the next step, 141 participants from private and public hospitals, insurance experts, Academic Associations of Midwifery, and policy makers in Maternity Health Affairs of Ministry of Health were invited to assess and provide feedback on the strategies that work to reduce cesarean deliveries. Results: Qualitative data analysis showed four concept related to increased cesarean delivery rates including; “standardization”, “education”, “amending regulations”, and “performance supervision”. Effective strategies extracted from qualitative data were rated by participants then, using ACCEPT derived from A as attainability, C as costing, C as complication, E as effectiveness, P as popularity, and T as timing table 19 strategies were detected as priorities. Conclusions: Although developing effective strategies to reduce cesarean delivery rates is complex process because of the multi-factorial nature of increased cesarean deliveries, in this study we have achieved strategies

  3. 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 ...

  4. 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.

  5. 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

  6. VOLATILIZATION RATES FROM WATER TO INDOOR AIR PHASE II

    EPA Science Inventory

    Contaminated water can lead to volatilization of chemicals to residential indoor air. Previous research has focused on only one source (shower stalls) and has been limited to chemicals in which gas-phase resistance to mass transfer is of marginal significance. As a result, attemp...

  7. 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...

  8. 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)

  9. 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.

  10. Rating procedure for mixed-air-source unitary air conditioners and heat pumps operating in the cooling mode

    SciTech Connect

    Domanski, P.A.

    1986-02-01

    A procedure is presented for rating split, residential air conditioners and heat pumps operating in the cooling mode that are made up of an evaporator unit combined with a condensing unit that has been rated under current procedures in conjunction with a different evaporator unit. The procedure allows calculation of capacity at the 95/sup 0/ F rating point and seasonal energy efficiency ratio, SEER, without performing laboratory tests of the complete system.

  11. Comparing variation in hospital rates of cesarean delivery among low-risk women using 3 different measures.

    PubMed

    Armstrong, Joanne C; Kozhimannil, Katy B; McDermott, Patricia; Saade, George R; Srinivas, Sindhu K

    2016-02-01

    This report describes the development of a measure of low-risk cesarean delivery by the Society for Maternal-Fetal Medicine (SMFM). Safely lowering the cesarean delivery rate is a priority for maternity care clinicians and health care delivery systems. Therefore, hospital quality assurance programs are increasingly tracking cesarean delivery rates among low-risk pregnancies. Two commonly used definitions of "low risk" are available, the Joint Commission (JC) and the Agency for Healthcare Research and Quality (AHRQ) measures, but these measures are not clinically comprehensive. We sought to refine the definition of the low-risk cesarean delivery rate to enhance the validity of the metric for quality measurement. We created this refined definition-called the SMFM definition-and compared it to the JC and AHRQ measures using claims-based data from the 2011 Nationwide Inpatient Sample of >863,000 births in 612 hospitals. Using these definitions, we calculated means and interquartile ranges (25th-75th percentile range) for hospital low-risk cesarean delivery rates, stratified by hospital size, teaching status, urban/rural location, and payer mix. Across all hospitals, the mean low-risk cesarean delivery rate was lowest for the SMFM definition (12.65%), but not substantially different from the JC and AHRQ measures (13.12% and 13.29%, respectively). We empirically examined the SMFM definition to ensure its validity and utility. This refined definition performs similarly to existing measures and has the added advantage of clinical perspective, enhanced face validity, and ease of use. PMID:26593970

  12. Correlation between indoor radon concentration and dose rate in air from terrestrial gamma radiation in Japan.

    PubMed

    Fujimoto, K

    1998-09-01

    A correlation between the indoor radon concentration and dose rate in air from terrestrial gamma radiation is studied using the results of nationwide indoor radon and external exposure surveys, although the surveys were not conducted at the same time nor at the same location. The radon concentration shows a log-normal-like distribution, whereas the terrestrial gamma radiation dose rate in air shows a normal-like distribution. A log-linear scatterplot for each pair of the indoor radon concentration and gamma-ray dose rate in air in each city reveals a clear relationship. The average, maximum, and minimum as well as regression line of radon concentration were found to increase with the gamma-ray dose rate in air. The group in higher quantile of radon concentration shows larger dependence on the gamma-ray dose rate. The rate of increase of radon concentration with the gamma-ray dose rate in air depends on the house structure. The wooden house has a larger rate of increase than the concrete house, and the regression lines cross at high air dose rate. Based on the finding in the present study a certain criterion level of air dose rate could be established and used for an effective survey to find out which houses might require a remedial action in conjunction with other screening tools. The criterion level of air dose rate might be more effective if the level is set for each house structure since the rate of increase of radon concentration depends on house structure. PMID:9721838

  13. Fractal structure of the distributions of air dose rates in Koriyama city in Fukushima.

    PubMed

    Ishihara, Masamichi

    2014-10-01

    The authors investigated the fractal structure of the distributions of air dose rates in Koriyama city in Fukushima using data published by the Fukushima Prefectural and Koriyama City governments. Relative frequency data of air dose rates (strength distribution) could be well fitted with a q-distribution. In the present analysis, the relative frequency decreases approximately as s for high air dose rate values, where the quantity s represents air dose rate. The fractal dimension is a function of the threshold sth of air dose rate. The fractal dimension is approximately 1.59 when sth is the average of the air dose rates in Koriyama (0.9 μSv h) and decreases with increasing the threshold: it is approximately 1.97 for sth = 0.6 μSv h and 1.40 for sth = 1.2 μSv h. These results confirm that the strength distribution behaves like a power function for high air dose rate values and that the fallout pattern can be described as a fractal. PMID:25162424

  14. 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). PMID:25944962

  15. Effect of room air recirculation delay on the decay rate of tracer gas concentration

    SciTech Connect

    Kristoffersen, A.R.; Gadgil, A.J.; Lorenzetti, D.M.

    2004-05-01

    Tracer gas measurements are commonly used to estimate the fresh air exchange rate in a room or building. Published tracer decay methods account for fresh air supply, infiltration, and leaks in ductwork. However, the time delay associated with a ventilation system recirculating tracer back to the room also affects the decay rate. We present an analytical study of tracer gas decay in a well-mixed, mechanically-ventilated room with recirculation. The analysis shows that failing to account for delays can lead to under- or over-estimates of the fresh air supply, depending on whether the decay rate calculation includes the duct volume.

  16. 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.

  17. Reducing the cesarean delivery rates for breech presentations: administration of spinal anesthesia facilitates manipulation to cephalic presentation, but is it cost saving?

    PubMed Central

    2014-01-01

    Background External cephalic version (ECV) is infrequently performed and 98% of breech presenting fetuses are delivered surgically. Neuraxial analgesia can increase the success rate of ECV significantly, potentially reducing cesarean delivery rates for breech presentation. The current study aims to determine whether the additional cost to the hospital of spinal anesthesia for ECV is offset by cost savings generated by reduced cesarean delivery. Methods In our tertiary hospital, three variables manpower, disposables, and fixed costs were calculated for ECV, ECV plus anesthetic doses of spinal block, vaginal delivery and cesarean delivery. Total procedure costs were compared for possible delivery pathways. Manpower data were obtained from management payroll, fixed costs by calculating cost/lifetime usage rate and disposables were micro-costed in 2008, expressed in 2013 NIS. Results Cesarean delivery is the most expensive option, 11670.54 NIS and vaginal delivery following successful ECV under spinal block costs 5497.2 NIS. ECV alone costs 960.21 NIS, ECV plus spinal anesthesia costs 1386.97 NIS. The highest individual cost items for vaginal, cesarean delivery and ECV were for manpower. Expensive fixed costs for cesarean delivery included operating room trays and postnatal hospitalization (minimum 3 days). ECV with spinal block is cheaper due to lower expected cesarean delivery rate and its lower associated costs. Conclusions The additional cost of the spinal anesthesia is offset by increased success rates for the ECV procedure resulting in reduction in the cesarean delivery rate. PMID:24564984

  18. Research: Care Delivery Development and validation of the Diabetes Medication System Rating Questionnaire-Short Form

    PubMed Central

    Peyrot, M; Xu, Y; Rubin, R R

    2014-01-01

    medications and between those using different insulin delivery devices. Conclusions This study suggests that the Diabetes Medication System Rating Questionnaire Short-Form provides a comprehensive set of measures with acceptable reliability and validity and a reduced burden of administration. What’s new? This study reports the development and validation of a short form of the Diabetes Medication System Rating Questionnaire (DMSRQ) that maintains the domains and performance of the long-form questionnaire. Like the Diabetes Medication System Rating Questionnaire, the Diabetes Medication System Rating Questionnaire-Short Form (DMSRQ-SF) has good reliability and enhanced validity relative to other comparable measures. The DMSRQ-SF has a lower burden of administration than the DMSRQ, which makes it suitable for use in clinical settings as well as research. Each of the DMSRQ-SF therapy perception items was chosen to have unique validity and applicability as a single-item measure, i.e. to assess an independent aspect of treatment satisfaction that discriminates treatments and drives global assessments of treatments. PMID:24673614

  19. 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...

  20. Increased planned delivery contributes to declining rates of pregnancy hypertension in Australia: a population-based record linkage study

    PubMed Central

    Roberts, Christine L; Algert, Charles S; Morris, Jonathan M; Ford, Jane B

    2015-01-01

    Objective Since the 1990s, pregnancy hypertension rates have declined in some countries, but not all. Increasing rates of early planned delivery (before the due date) have been hypothesised as the reason for the decline. The aim of this study was to explore whether early planned delivery can partly explain the declining pregnancy hypertension rates in Australia. Design Population-based record linkage study utilising linked birth and hospital records. Setting and participants A cohort of 1 076 122 deliveries in New South Wales, Australia, 2001–2012. Outcome measures Pregnancy hypertension (including gestational hypertension, pre-eclampsia and eclampsia) was the main outcome; pre-eclampsia was a secondary outcome. Results From 2001 to 2012, pregnancy hypertension rates declined by 22%, from 9.9% to 7.7%, and pre-eclampsia by 27%, from 3.3% to 2.4% (trend p<0.0001). At the same time, planned deliveries increased: prelabour caesarean section by 43% (12.9–18.4%) and labour inductions by 10% (24.8–27.2%). Many maternal risk factors for pregnancy hypertension significantly increased (p<0.01) over the study period including nulliparity, age ≥35 years, diabetes, overweight and obesity, and use of assisted reproductive technologies; some risk factors decreased including multifetal pregnancies, age <20 years, autoimmune diseases and previous pregnancy hypertension. Given these changes in risk factors, the pregnancy hypertension rate was predicted to increase to 10.5%. Examination of annual gestational age distributions showed that pregnancy hypertension rates actually declined from 38 weeks gestation and were steepest from 41 weeks; at least 36% of the decrease could be attributed to planned deliveries. The risk factors for pregnancy hypertension were also risk factors for planned delivery. Conclusions It appears that an unanticipated consequence of increasing early planned deliveries is a decline in the incidence of pregnancy hypertension. Women with risk

  1. 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 ...

  2. Daily changes in oxygen saturation and pulse rate associated with particulate air pollution and barometric pressure.

    PubMed

    Dockery, D W; Pope, C A; Kanner, R E; Martin Villegas, G; Schwartz, J

    1999-01-01

    Epidemiologic studies have linked fine particulate air pollution with increases in morbidity and mortality rates from cardiopulmonary complications. Although the underlying biologic mechanisms responsible for this increase remain largely unknown, potential pathways include transient declines in blood oxygenation and changes in pulse rate following exposures to particulate air pollution episodes. This study evaluated potential associations between daily measures of respirable particulate matter (PM) with pulse rate and oxygen saturation of the blood. Pulse rate and oxygen saturation (Spo2) using pulse oximetry were measured daily in 90 elderly subjects living near air pollution monitors during the winter of 1995-96 in Utah Valley. We also evaluated potential associations of oxygen saturation and pulse rate with barometric pressure. Small but statistically significant positive associations between day-to-day changes in Spo2 and barometric pressure were observed. Pulse rate was inversely associated with barometric pressure. Exposure to particulate pollution was not significantly associated with Spo2 except in male participants 80 years of age or older. Increased daily pulse rate, as well as the odds of having a pulse rate 5 or 10 beats per minute (bpm) above normal (normal is defined as the individual's mean pulse rate throughout the study period), were significantly associated with exposure to particulate pollution on the previous 1 to 5 days. The medical or biologic relevance of these increases in pulse rate following exposure to particulate air pollution requires further study. PMID:10192116

  3. Dosimetric Effects of Air Pockets Around High-Dose Rate Brachytherapy Vaginal Cylinders

    SciTech Connect

    Richardson, Susan; Palaniswaamy, Geethpriya; Grigsby, Perry W.

    2010-09-01

    Purpose: Most physicians use a single-channel vaginal cylinder for postoperative endometrial cancer brachytherapy. Recent published data have identified air pockets between the vaginal cylinders and the vaginal mucosa. The purpose of this research was to evaluate the incidence, size, and dosimetric effects of these air pockets. Methods and Materials: 25 patients receiving postoperative vaginal cuff brachytherapy with a high-dose rate vaginal cylinders were enrolled in this prospective data collection study. Patients were treated with 6 fractions of 200 to 400 cGy per fraction prescribed at 5 mm depth. Computed tomography simulation for brachytherapy treatment planning was performed for each fraction. The quantity, volume, and dosimetric impact of the air pockets surrounding the cylinder were quantified. Results: In 25 patients, a total of 90 air pockets were present in 150 procedures (60%). Five patients had no air pockets present during any of their treatments. The average number of air pockets per patient was 3.6, with the average total air pocket volume being 0.34 cm{sup 3} (range, 0.01-1.32 cm{sup 3}). The average dose reduction to the vaginal mucosa at the air pocket was 27% (range, 9-58%). Ten patients had no air pockets on their first fraction but air pockets occurred in subsequent fractions. Conclusion: Air pockets between high-dose rate vaginal cylinder applicators and the vaginal mucosa are present in the majority of fractions of therapy, and their presence varies from patient to patient and fraction to fraction. The existence of air pockets results in reduced radiation dose to the vaginal mucosa.

  4. Tolerability of Nasal Delivery of Humidified and Warmed Air at Different Temperatures: A Randomised Double-Blind Pilot Study

    PubMed Central

    Bibby, Susan; Reddy, Sumeet; Cripps, Terrianne; McKinstry, Steve; Weatherall, Mark; Beasley, Richard; Pilcher, Janine

    2016-01-01

    Objectives. Delivery of warmed, humidified air via nasal high flow therapy could potentially reduce replication of temperature-sensitive viruses in the upper respiratory tract. This study investigates whether nasal high flow therapy is well tolerated by healthy adults at 37°C and 41°C. Methods. In this randomised, double-blind, controlled crossover pilot trial, nasal high flow therapy was used to deliver humidified air at 35 L/min, at either 37°C or 41°C, for three one-hour sessions of use over one day. The alternative was delivered at least 14 days later. Ten healthy, nonsmoking adults were asked, via questionnaire after each day's use, whether they would use nasal high flow therapy while being unwell with a cold or flu if it was demonstrated to improve symptoms. Results. All participants completed both interventions. Eighty percent responded “yes” to future use of nasal high flow therapy, for both 37°C and 41°C. There was no significant change from baseline in saccharin times following either intervention or in the following morning. Conclusions. Delivering humidified air via nasal high flow therapy at both 37°C and 41°C is well tolerated by healthy adults. This supports investigation into the potential use of nasal high flow therapy as treatment in viral upper respiratory tract infections. Trial Registration. This trial is registered with ACTRN12614000183684 (tolerability study of nasal delivery of humidified & warmed air). PMID:27127650

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

    NASA Astrophysics Data System (ADS)

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

    2015-01-01

    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

  6. 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

  7. 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...

  8. 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.

  9. Reaction rate constant for dry air oxidation of K Basin fuel

    SciTech Connect

    Trimble, D.J.

    1998-04-29

    The rate of oxidation of spent nuclear fuel stored in the K Basin water is an important parameter when assessing the processes and accident scenarios for preparing the fuel for dry storage. The literature provides data and rate laws for the oxidation of unirradiated uranium in various environments. Measurement data for the dry air oxidation of K Basin fuel is compared to the literature data for linear oxidation in dry air. Equations for the correlations and statistical bounds to the K Basin fuel data and the literature data are selected for predicting nominal and bounding rates for the dry air oxidation of the K Basin fuel. These rate equations are intended for use in the Spent Nuclear Fuel Project Technical Data book.

  10. 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

  11. 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.

  12. On the accuracy of the rate coefficients used in plasma fluid models for breakdown in air

    NASA Astrophysics Data System (ADS)

    Kourtzanidis, Konstantinos; Raja, Laxminarayan L.

    2016-07-01

    The electrical breakdown of air depends on the balance between creation and loss of charged particles. In fluid models, datasets of the rate coefficients used are obtained either from fits to experimental data or by solutions of the Boltzmann equation. Here, we study the accuracy of the commonly used models for ionization and attachment frequencies and their impact on the prediction of the breakdown threshold for air. We show that large errors can occur depending on the model and propose the most accurate dataset available for modeling of air breakdown phenomena.

  13. 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 ...

  14. Air and silica core Bragg fibers for radiation delivery in the wavelength range 0.6-1.5 μ m

    NASA Astrophysics Data System (ADS)

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

    2016-09-01

    This paper presents fundamental characteristics of laboratory designed and fabricated Bragg fibers with air and silica cores at wavelengths of 632, 975, 1064 and 1550 nm. Fibers with the 26- μ m-silica core and 5- or 73- μ m-air cores in diameters and claddings of 3 pairs of Bragg layers were prepared from one preform. The overall transmittance, attenuation coefficients, coupling losses, bending losses, and damage-intensity thresholds were determined using four continuous-wave laser sources with the maximum output power of 300 mW and a pulsed 9 ns laser with the maximum output energy up to 1 mJ. The lowest attenuation coefficient of about 70 dB/km was determined at 1064 nm with the 73- μ m-air-core Bragg fiber. All fibers have been found to exhibit negligible bending losses down to the bending diameters of 5 cm. In comparison with the conventional gradient optical fiber, all the prepared Bragg fibers have approximately six times higher damage intensity threshold of about 30 GWcm-2 and therefore they are very suitable for high power laser radiation delivery.

  15. Long-term dynamics of death rates of emphysema, asthma, and pneumonia and improving air quality

    PubMed Central

    Kravchenko, Julia; Akushevich, Igor; Abernethy, Amy P; Holman, Sheila; Ross, William G; Lyerly, H Kim

    2014-01-01

    Background The respiratory tract is a major target of exposure to air pollutants, and respiratory diseases are associated with both short- and long-term exposures. We hypothesized that improved air quality in North Carolina was associated with reduced rates of death from respiratory diseases in local populations. Materials and methods We analyzed the trends of emphysema, asthma, and pneumonia mortality and changes of the levels of ozone, sulfur dioxide (SO2), nitrogen dioxide (NO2), carbon monoxide (CO), and particulate matters (PM2.5 and PM10) using monthly data measurements from air-monitoring stations in North Carolina in 1993–2010. The log-linear model was used to evaluate associations between air-pollutant levels and age-adjusted death rates (per 100,000 of population) calculated for 5-year age-groups and for standard 2000 North Carolina population. The studied associations were adjusted by age group-specific smoking prevalence and seasonal fluctuations of disease-specific respiratory deaths. Results Decline in emphysema deaths was associated with decreasing levels of SO2 and CO in the air, decline in asthma deaths–with lower SO2, CO, and PM10 levels, and decline in pneumonia deaths–with lower levels of SO2. Sensitivity analyses were performed to study potential effects of the change from International Classification of Diseases (ICD)-9 to ICD-10 codes, the effects of air pollutants on mortality during summer and winter, the impact of approach when only the underlying causes of deaths were used, and when mortality and air-quality data were analyzed on the county level. In each case, the results of sensitivity analyses demonstrated stability. The importance of analysis of pneumonia as an underlying cause of death was also highlighted. Conclusion Significant associations were observed between decreasing death rates of emphysema, asthma, and pneumonia and decreases in levels of ambient air pollutants in North Carolina. PMID:25018627

  16. Experiments probing the influence of air exchange rates on secondary organic aerosols derived from indoor chemistry

    NASA Astrophysics Data System (ADS)

    Weschler, Charles J.; Shields, Helen C.

    Reactions between ozone and terpenes have been shown to increase the concentrations of submicron particles in indoor settings. The present study was designed to examine the influence of air exchange rates on the concentrations of these secondary organic aerosols as well as on the evolution of their particle size distributions. The experiments were performed in a manipulated office setting containing a constant source of d-limonene and an ozone generator that was remotely turned "on" or "off" at 6 h intervals. The particle number concentrations were monitored using an optical particle counter with eight-channels ranging from 0.1-0.2 to>2.0 μm diameter. The air exchange rates during the experiments were either high (working hours) or low (non-working hours) and ranged from 1.6 to>12 h -1, with intermediate exchange rates. Given the emission rates of ozone and d-limonene used in these studies, at an air exchange rate of 1.6 h -1 particle number concentration in the 0.1-0.2 μm size-range peaked 1.2 h after the ozone generator was switched on. In the ensuing 4.8 h particle counts increased in successive size-ranges up to the 0.5-0.7 μm diameter range. At higher air exchange rates, the resulting concentrations of total particles and particle mass (calculated from particle counts) were smaller, and at exchange rates exceeding 12 h -1, no excess particle formation was detectable with the instrument used in this study. Particle size evolved through accretion and, in some cases, coagulation. There was evidence for coagulation among particles in the smallest size-range at low air exchange rates (high particle concentrations) but no evidence of coagulation was apparent at higher air exchange rates (lower particle concentrations). At higher air exchange rates the particle count or size distributions were shifted towards smaller particle diameters and less time was required to achieve the maximum concentration in each of the size-ranges where discernable particle growth

  17. Attenuation effects on the kerma rates in air after cesium depositions on grasslands.

    PubMed

    Jacob, P; Meckbach, R; Paretzke, H G; Likhtarev, I; Los, I; Kovgan, L; Komarikov, I

    1994-01-01

    Since the reactor accident of Chernobyl, cesium depth profiles and nuclide-specific kerma rates in air have been determined for various grassland sites in south Bavaria and in Ukraine. The sites are described by soil characteristics, annual precipitation, distance from release point, mode of deposition, and activity per unit area. The effects of surface roughness and migration of cesium into the soil on the kerma rate in air over grasslands was determined by two methods. The kerma rates in air obtained by the evaluations of in situ gamma-ray spectrometry results and of measured activity distributions in the soil showed only negligible differences for the observation period of 6 years after deposition. For the sites in Ukraine the kerma rate in air per activity per unit area was found to be systematically 40% higher than in Bavaria. The results from Bavaria on the attenuation of the kerma rate and a data set, including experiences from the weapons test fallout, are analytically approximated as a function of time up to 25 years after deposition. PMID:7809371

  18. Measurement of air exchange rates in residential and commercial buildings in the northwest: techniques and results

    SciTech Connect

    Parker, G.B.

    1985-04-01

    In a study of air exchange rates in commercial and residential buildings, several techniques were employed to measure the air exchange: analysis of sulfur hexafluoride tracer gas decay using a portable gas chromatograph; analysis of carbon monoxide decay using a continuous infrared analyzer; analysis of nitrogen oxides decay using a continuous oxides of nitrogen analyzer; and analysis of perfluorocarbon tracer (PFT) gas using a programmable automatic sampler, and a passive capillary tube sampler. Using sulfur hexafluoride tracer gas with real-time chromatography was the most labor-intensive method, requiring constant attention for several hours; whereas, analyzing the decay of PFT tracer gas using small capillary tubes required little setup time and virtually no attention. However, the analysis of tracer gas captured by the capillary tubes was difficult and was performed using special analysis equipment. The air exchange rate measured in the commercial buildings ranged from 5 to 0.04 air changes per hour (ACH) depending on the type of heating, ventilation, and air conditioning (HVAC) system. Air exchange in the residential structures ranged from about 1 ACH to about 0.3 ACH. 6 refs., 5 tabs., 3 figs.

  19. 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

  20. 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.

  1. 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 ...

  2. 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...

  3. Spray droplet sizes with additives discharged from an air-assisted variable-rate nozzle

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Understanding droplet size distributions is essential to achieve constant spray quality for real-time variable-rate sprayers that synchronize spray outputs with canopy structures. Droplet sizes were measured for a custom-designed, air-assisted, five-port nozzle coupled with a pulse width modulated (...

  4. 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...

  5. 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. PMID:24809924

  6. 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.

  7. 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.

  8. The measurement of water vapour transfer rate through clothing system with air gap between layers

    NASA Astrophysics Data System (ADS)

    Oh, Ae-Gyeong

    2008-02-01

    The experiments described in this paper are designed to test the water vapour transfer rates through outdoor clothing system with air gap between layers under conditions more closely actual wear. It was adopted distance of 5 mm to ensure no disturbance of the air gap thickness between layers throughout the measurement period with all fabrics. The results have indicated that the water vapour transfer rates of clothing system decrease very slightly with time, it is shown that they approached nearly equilibrium state throughout the experiment. It is revealed that the water vapour transfer rates of the clothing system were ordered into groups determined by the type of waterproof breathable fabric as a shell layer being ordered.

  9. 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.

  10. 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.

  11. Developing IntegRATE: a fast and frugal patient-reported measure of integration in health care delivery

    PubMed Central

    Elwyn, Glyn; Thompson, Rachel; John, Roshen; Grande, Stuart W

    2015-01-01

    Background Efforts have been made to measure integration in health care delivery, but few existing instruments have adopted a patient perspective, and none is sufficiently generic and brief for administration at scale. We sought to develop a brief and generic patient-reported measure of integration in health care delivery. Methods Drawing on both existing conceptualisations of integrated care and research on patients’ perspectives, we chose to focus on four distinct domains of integration: information sharing, consistent advice, mutual respect and role clarity. We formulated candidate items and conducted cognitive interviews with end users to further develop and refine the items. We then pilot-tested the measure. Results Four rounds of cognitive interviews were conducted (n = 14) and resulted in a four-item measure that was both relevant and understandable to end users. The pilot administration of the measure (n = 15) further confirmed the relevance and interpretability of items and demonstrated that the measure could be completed in less than one minute. Conclusions This new measure, IntegRATE, represents a patient-reported measure of integration in health care delivery that is conducive to use in both routine performance monitoring and research. The psychometric properties of the measure will be assessed in the next stage of development. PMID:26034467

  12. What is the most relevant standard of success in assisted reproduction?: The cumulated singleton/twin delivery rates per oocyte pick-up: the CUSIDERA and CUTWIDERA.

    PubMed

    Germond, Marc; Urner, Françoise; Chanson, Alain; Primi, Marie-Pierre; Wirthner, Daniel; Senn, Alfred

    2004-11-01

    National and international registries are essential tools for establishing new standards and comparing success rates, but they do not take into account the total pregnancy/delivery rate per oocyte recovery. In Switzerland and Germany, because of legal constraints, a maximum of three two-pronuclear zygotes are allocated for transfer whereas all the supernumerary pronuclear zygotes are immediately cryopreserved, preventing selection of the transferred embryos. We report on a 10 years' experience (1993-2002) of our centre which performs transfers of unselected embryos and cryopreservation at the two-pronuclear zygote stage. As approximately 30% of all deliveries are from cryo cycles, it is essential to take into account the contribution of the cryo transfers, and we propose therefore to evaluate, as a measure of IVF performance, the cumulated delivery rate per oocyte pick-up. This delivery rate is broken down further into the cumulated singleton delivery rate (CUSIDERA) and the cumulated twin delivery rate (CUTWIDERA). The sum (S) of these two rates is a measure of efficacy while the ratio CUTWIDERA/S as a percentage is a measure of safety of IVF treatments. Using these new indexes, the average 10 year efficacy and safety of our IVF programme were 26 and 19%, respectively. Both CUSIDERA and CUTWIDERA can be calculated easily in any clinical situation and yield useful parameters for patient counselling and internal/external benchmarking purposes. PMID:15358719

  13. Age of air and heating rates: comparison of ERA-40 with ERA-Interim

    NASA Astrophysics Data System (ADS)

    Legras, B.; Fueglistaler, S.

    2009-04-01

    The age of air in the stratosphere is often used as a test for the good representation of the Brewer-Dobson circulation by atmospheric models. This is a critical requirement to modelize the distribution of long-lived species in chemical models. It is often advocated that using heating rates for vertical transport in the stratosphere performs better that standard analysed velocities from weather centers. This work is based on an extensive comparison of the age of air using 5 years of heating rates from the ERA-40 reanalysis and from the new ERA-interim reanalysis built with 4D-Var assimilation. The ERA-40 exhibits both too young ages with analyzed velocities and too old ages with heating rates. The reason for too young ages is spurious transport associated with too noisy wind, as a result of 3D-Var assimilation. Heating rates provide a much less noisy meridional circulation and preserve transport barriers and polar vortex confinement. However, excessive cooling near 30 hPa in the tropics blocks the ascending motion within the tropical pipe over extended periods of time inducing very old ages. This effect is usually corrected by an empirical correction which can exceed in some regions the calculated heating rate in magnitude, with opposite sign. We relate this correction to the assimilation temperature increment that is required to compensate the bias of the model, notably the excessive negative heat transport due to the noisy vertical velocities and the lack of mass conservation in the isentropic frame. The new ERA-interim exhibits much reduced noise in the vertical velocity and is ten times less diffusive than the ERA-40 in the tropics. Age of air is then found to be slightly older than given by the observations. The biases in the heating rate have also been considerably reduced with respect to ERA-40 and the assimilation increment is now only a fraction of the heating rate. The age of air is in fairly good aggreement with the observations at 20 km and higher

  14. 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. PMID:25827258

  15. 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.

  16. A Subgrid Model for Predicting Air Entrainment Rates in Bubbly Flows

    NASA Astrophysics Data System (ADS)

    Ma, Jingsen; Oberai, Assad A.; Drew, Donald E.; Lahey, Richard T., Jr.; Moraga, Francisco J.

    2008-11-01

    In this talk we present a fairly simple subgrid air entrainment model that accurately predicts the rate of air entrainment, which is critical in simulating multiphase (air/water) flows. The derivation of this model begins by assuming that a thin sheet of air is carried into the water by the inertia of the liquid at the free surface. A momentum balance on the entrained gas layer results in an expression for the entrained volumetric gas flow rate, in terms of the local liquid velocity, gas viscosity etc., which are readily available from a multiphase RANS-type simulation. This model has been validated against extensive experimental data on both plunging jets and hydraulic jumps over a wide range of liquid velocities. It was implemented in a two-fluid computational fluid dynamics code (CFDShipM) to be used to predict the void fraction distribution underneath a plunging liquid jet at different depths and jet velocities. The results were found to match the experimental observations very well. The application of this model to more challenging problems, including hydraulic jumps and full-scale ship simulations, is currently underway.

  17. 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.

  18. 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).

  19. 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).

  20. The water delivery system affects the rate of weight gain in C57BL/6J mice during the first week after weaning.

    PubMed

    Gordon, Alexander; Wyatt, Jeff

    2011-01-01

    Facility planners, IACUCs, veterinary staff, and researchers make choices on water delivery systems for rodents on the basis of cost effectiveness, water quality, risk of malfunction, and potential effect on animal health and welfare. Here we compare biometrics, including weight trends, of newly arrived mice unfamiliar with automated watering; weight trends of weanlings; fecundity of mice; and risk of malfunction among 3 water delivery techniques: water bottle only, combination of automated delivery and water bottle, and automated system only. There was no statistically significant difference among the 3 experimental groups with respect to fecundity, mortality, and delivery malfunction. On the basis of body weight trends, the health and wellbeing of the mice used in these studies were not affected by the water delivery system or housing density after the first week; however, there was a significant difference in the growth rate at 21 to 28 d of age among the 3 groups of pups. The mice receiving both automated delivery and water bottles experienced higher growth rates from 21 to 28 d of age than did the other experimental groups. However, after 35 d of age, weight trends did not differ among the groups. Our results suggest that mice weaned into the same method of water delivery as their respective dams thrive equally well among the 3 tested water delivery systems. PMID:21333161

  1. 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..., LIBRARY OF CONGRESS COPYRIGHT ARBITRATION ROYALTY PANEL RULES AND PROCEDURES ADJUSTMENT OF ROYALTY PAYABLE UNDER COMPULSORY LICENSE FOR MAKING AND DISTRIBUTING PHONORECORDS § 255.5 Royalty rate for...

  2. 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

    2016-01-01

    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%/2mm

  3. Enhancement of topical delivery of drugs via direct penetration by reducing blood flow rate in skin.

    PubMed

    Higaki, K; Nakayama, K; Suyama, T; Amnuaikit, Chomchan; Ogawara, K; Kimura, T

    2005-01-20

    The purpose of this work was to investigate the effect of blood flow in the skin on the direct penetration of topically applied drugs into the muscular layer, and to show that the skin blood flow could also be one of the important factors determining the direct penetration of drugs to the muscular layer. In vivo percutaneous absorption study was performed for antipyrine, salicylic acid or diclofenac by using rats with tape-stripped skin. Phenylephrine, which is well known to reduce the local blood flow by vasoconstrictor action, was topically applied to decrease the local blood flow in the skin. The concentrations of drugs in viable skin and muscle, and the local blood flow in the skin under the applied and the contralateral sites were determined to evaluate the effect of the local blood flow on the delivery of topically applied drugs into the muscular layer. Dose dependency for the effect of phenylephrine was, first of all, investigated for antipyrine in the range from 0.4 to 10 micromol. The distribution of antipyrine into the viable skin and muscular layer 2 h after topical application significantly increased, but the effect of phenylephrine was saturated around 2 micromol and the dose-dependent profiles for both tissues were almost superimposed. On the other hand, the fraction dose absorbed, plasma concentration and concentrations in viable skin and muscular layer under the contralateral site showed the decreasing tendency and the saturation of the effect around 2 micromol. To confirm the effect of phenylephrine on the local blood flow in the skin, the skin blood flow was measured 2 h after topical application of 2 micromol phenylephrine, and the significant decrease in the blood flow was recognized. In vivo percutaneous absorption studies were performed for salicylic acid and diclofenac, too. Extensive enhancement of penetration into the viable skin and muscular layer was observed for both drugs, although total absorption from the donor cell showed the

  4. Risk of sick leave associated with outdoor air supply rate, humidification, and occupant complaints.

    PubMed

    Milton, D K; Glencross, P M; Walters, M D

    2000-12-01

    We analyzed 1994 sick leave for 3,720 hourly employees of a large Massachusetts manufacturer, in 40 buildings with 115 independently ventilated work areas. Corporate records identified building characteristics and IEQ complaints. We rated ventilation as moderate (approximately 25 cfm/person, 12 ls-1) or high (approximately 50 cfm/person, 24 ls-1) outdoor air supply based on knowledge of ventilation systems and CO2 measurements on a subset of work areas, and used Poisson regression to analyze sick leave controlled for age, gender, seniority, hours of non-illness absence, shift, ethnicity, crowding, and type of job (office, technical, or manufacturing worker). We found consistent associations of increased sick leave with lower levels of outdoor air supply and IEQ complaints. Among office workers, the relative risk for short-term sick leave was 1.53 (95% confidence 1.22-1.92) with lower ventilation, and 1.52 (1.18-1.97) in areas with IEQ complaints. The effect of ventilation was independent of IEQ complaints and among those exposed to lower outdoor air supply rates the attributable risk of short-term sick leave was 35%. The cost of sick leave attributable to ventilation at current recommended rates was estimated as $480 per employee per year at Polaroid. These findings suggest that net savings of $400 per employee per year may be obtained with increased ventilation. Thus, currently recommended levels of outdoor air supply may be associated with significant morbidity, and lost productivity on a national scale could be as much as $22.8 billion per year. Additional studies of IEQ impacts on productivity and sick leave, and the mechanisms underlying the apparent association are needed. PMID:11089326

  5. 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

  6. 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. PMID:25821853

  7. 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. PMID:26333637

  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. Establishment of air kerma reference standard for low dose rate Cs-137 brachytherapy sources.

    PubMed

    Sharma, Sunil Dutt; Kumar, Sudhir; Srinivasan, P; Chourasiya, G

    2011-01-01

    A guarded cylindrical graphite ionization chamber of nominal volume 1000 cm3 was designed and fabricated for use as a reference standard for low-dose rate 137Cs brachytherapy sources. The air kerma calibration coefficient (N(K)) of this ionization chamber was estimated analytically using Burlin's general cavity theory, as well as by the Monte Carlo simulation and validated experimentally using Amersham CDCS-J-type 137Cs reference source. In the analytical method, the N(K) was calculated for 662 keV gamma rays of 137Cs brachytherapy source. In the Monte Carlo method, the geometry of the measurement setup and physics-related input data of the 137Cs source and the surrounding material were simulated using the Monte Carlo N-Particle code. The photon energy fluence was used to arrive at the reference air kerma rate (RAKR) using mass energy absorption coefficient. The energy deposition rates were used to simulate the value of charge rate in the ionization chamber, and the N(K) was determined. The analytical and Monte Carlo values of N(K) of the cylindrical graphite ionization chamber for 137Cs brachytherapy source are in agreement within 1.07%. The deviation of analytical and Monte Carlo values from experimental values of N(K) is 0.36% and 0.72%, respectively. This agreement validates the analytical value, and establishes this chamber as a reference standard for RAKR or AKS measurement of 137Cs brachytherapy sources. PMID:22089009

  10. Method and apparatus for measuring the rate at which air infiltrates into and out of buildings

    SciTech Connect

    Dempsey, J. C.

    1985-01-15

    Tracer emission sources which emit tracer gas at a predetermined constant known rate are distributed throughout a building. The preferred source is a small vessel containing a vaporous perfluorocarbon tracer (PFT) substance having a very small bore hole in the top through which the PFT vapor can escape. Time is permitted for the tracer gas to mix uniformly throughout the building and for its concentration to equilibrate with infiltrating air. The concentration of the tracer is then measured and compared to the known volume of air in the building to determine the infiltration rate. In the preferred mode, the concentration is integrated and measured by continuously sampling the tracer gas at a constant rate on activated charcoal adsorbent over a period of several weeks. The amount of tracer substance accumulated on the adsorbent at the end of the test is directly related to the average tracer gas concentration which existed in the building during the sampling period and it can therefore be used to calculate an average infiltration rate during that period.

  11. 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. PMID:20948928

  12. 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

  13. Distribution and variability of the 24-h average air exchange rates and interzonal flow rates in 26 Japanese residences in 5 seasons

    NASA Astrophysics Data System (ADS)

    Shinohara, Naohide; Kataoka, Toshiyuki; Takamine, Koichi; Gamo, Masashi

    2011-07-01

    In this study, to evaluate the distribution of air exchange rates in Japan, daily, seasonal, and inter-residence variabilities were determined as well as the air exchange rate itself. In addition, airflows among multiple zones were also evaluated. For this purpose, the 24 h average air exchange rates and interzonal air flow rates were measured using a passive perfluorocarbon tracer (PFT) method with three kinds of tracer gases for 1 week in three rooms of 26 Japanese residences over five seasons: summer and autumn of 2005, and winter, spring, and summer of 2006. During these seasons, the weekly average air exchange rates were found to be 1.6 ± 1.7, 0.58 ± 0.94, 0.61 ± 0.93, 1.2 ± 2.5, and 1.7 ± 1.8 h -1, respectively. Two-way repeated measure analysis of variance (ANOVA) revealed that the air exchange rates differed significantly with respect to the seasons, residences, and interaction of seasons and residences ( p < 0.01). In addition, the air exchange rates in both summers and spring were statistically higher than those in autumn and winter (Sheffe test, p < 0.01). According to the ANOVA, the percentage contribution of inter-residence variability, seasonal variability, interaction of seasonal and inter-residence variabilities, and daily variability to the total variability of the 24 h average air exchange rates in the present survey was 51%, 44%, 3.7%, and 1.0%, respectively.

  14. 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

  15. Dissolution Rate Enhancement, Design and Development of Buccal Drug Delivery of Darifenacin Hydroxypropyl β-Cyclodextrin Inclusion Complexes

    PubMed Central

    Jagdale, Swati C.; Mohanty, Prachyasuman; Chabukswar, Aniruddha R.; Kuchekar, Bhanudas S.

    2013-01-01

    Darifenacin is a urinary antispasmodic. The oral absorption of darifenacin is poor due to its low solubility and poor bioavailability (15–19%). Darifenacin was complexed with hydroxylropyl beta-cyclodextrin (Hpβ-CD). The best results were obtained with the coevaporation that interacts in a 1 : 1 drug : cyclodextrin molar ratio. The solid inclusion complexes were found to be amorphous in the characterization. The dissolution rate of darifenacin from the Hpβ-CD solid inclusion complex was increased compared to the powdered drug. The controlled release buccoadhesive patches for the delivery of darifenacin were prepared using HPMC K100M CR and HPMC K15. The coevaporation complex of the drug was used in the formulation due to its increased saturation solubility and increased ease of dissolution. The patches were evaluated for their surface pH, folding endurance, swelling, mucoadhesive properties, in vitro residence time, vapour transmission test, and in vitro and ex vivo release studies. Formulations Hb2 (2%) and Pb4 (4%) were found to be optimized. These two formulations can be used for buccal delivery of darifenacin which avoids first pass effect and leads to increased bioavailability of darifenacin. PMID:26556003

  16. The rate of intravenous cocaine or amphetamine delivery: influence on drug-taking and drug-seeking behavior in rats

    PubMed Central

    Crombag, Hans S.; Ferrario, Carrie R.; Robinson, Terry E.

    2008-01-01

    We studied the influence of rate of intravenous infusion of cocaine or amphetamine on drug-taking and seeking behavior. First, drug-naive rats were tested for acquisition of self-administration of increasing doses of amphetamine or cocaine infused over 5 or 100s. Second, self-administration of cocaine or amphetamine infused over 5–100 sec was assessed on fixed or progressive-ratio (PR) reinforcement schedules. Finally, the ability of a single 5 or 100 sec amphetamine or cocaine infusion to reinstate extinguished drug seeking was assessed. Although slower infusion rates produced a small effect on drug taking under continuous-reinforcement conditions, infusion rate did not alter drug taking on intermittent or PR reinforcement schedules, or the ability of cocaine or amphetamine to reinstate drug seeking. Taken together, our results suggest that variation in drug delivery rate over a range that we previously found alters the induction of behavioral sensitization, gene-expression and striatal dopamine activity, does not markedly alter drug-taking or seeking behavior. PMID:18586051

  17. 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…

  18. Survey Platform: A Factor Influencing Online Survey Delivery and Response Rate

    ERIC Educational Resources Information Center

    Nair, Chenicheri Sid; Adams, Phillip

    2009-01-01

    Online surveys in general are advantageous because of the ease of administration, collection and storing of data resulting in monetary and time savings. Though research in general shows the advantages to be beneficial, the down-side to such online surveys has been the response rate. The aim of this paper is to initiate a discussion where one…

  19. Cryotop vitrification of human oocytes results in high survival rate and healthy deliveries.

    PubMed

    Antinori, Monica; Licata, Emanuele; Dani, Gianluca; Cerusico, Fabrizio; Versaci, Caterina; Antinori, Severino

    2007-01-01

    Vitrification, an ultra-rapid cooling technique, offers a new perspective in attempts to develop an optimal cryopreservation procedure for human oocytes and embryos. To further evaluate this method for human oocytes, 796 mature oocytes (metaphase II) were collected from 120 volunteers. Since Italian legislation allows the fertilization of a maximum of only three oocytes per woman, there were 463 supernumerary oocytes; instead of being discarded, they were vitrified. When, in subsequent cycles, these oocytes were utilized, 328 out of 330 (99.4%) oocytes survived the warming procedure. The fertilization rate, pregnancy rate and implantation rate per embryo were 92.9, 32.5 and 13.2% respectively. Thus, as already reported in the literature, the vitrification procedure seems to be highly effective, safe (since healthy babies have been born) and easy to apply. In situations where embryo cryopreservation is not permitted (as in Italy), there is now good indication for routine application of the method, once further standardization is achieved. PMID:17207335

  20. 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.

  1. Joint source/FEC rate selection for quality-optimal MPEG-2 video delivery.

    PubMed

    Frossard, P; Verscheure, O

    2001-01-01

    This paper deals with the optimal allocation of MPEG-2 encoding and media-independent forward error correction (FEC) rates under a total given bandwidth. The optimality is defined in terms of minimum perceptual distortion given a set of video and network parameters. We first derive the set of equations leading to the residual loss process parameters. That is, the packet loss ratio (PLR) and the average burst length after FEC decoding. We then show that the perceptual source distortion decreases exponentially with the increasing MPEG-2 source rate. We also demonstrate that the perceptual distortion due to data loss is directly proportional to the number of lost macroblocks, and therefore decreases with the amount of channel protection. Finally, we derive the global set of equations that lead to the optimal dynamic rate allocation. The optimal distribution is shown to outperform classical FEC scheme, thanks to its adaptivity to the scene complexity, the available bandwidth and to the network performance. Furthermore, our approach holds for any standard video compression algorithms (i.e., MPEG-x, H.26x). PMID:18255521

  2. Evaluation of passive air sampler calibrations: Selection of sampling rates and implications for the measurement of persistent organic pollutants in air

    NASA Astrophysics Data System (ADS)

    Melymuk, Lisa; Robson, Matthew; Helm, Paul A.; Diamond, Miriam L.

    2011-04-01

    Polyurethane foam (PUF) passive air samplers (PAS) are a common and highly useful method of sampling persistent organic pollutants (POP) concentrations in air. PAS calibration is necessary to obtain reasonable and comparable semi-quantitative measures of air concentrations. Various methods are found in the literature concerning PAS calibration. 35 studies on PAS use and calibration are examined here, in conjunction with a study involving 10 PAS deployed concurrently in outdoor air with a low-volume air sampler in order to measure the sampling rates of PUF-PAS for polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), polycyclic musks (PCMs), and polycyclic aromatic hydrocarbons (PAHs). Based on this analysis it is recommended that (1) PAS should be assumed to represent bulk rather than gas-phase compound concentrations due to the sampling of particle-bound compounds, (2) calibration of PAS sampling rates is more accurately achieved using an active low-volume air sampler rather than depuration compounds since the former measures gas- and particle-phase compounds and does so continuously over the deployment period of the PAS, and (3) homolog-specific sampling rates based on KOA groupings be used in preference to compound/congener-specific or single sampling rates.

  3. Ambient temperature, air pollution, and heart rate variability in an aging population.

    PubMed

    Ren, Cizao; O'Neill, Marie S; Park, Sung Kyun; Sparrow, David; Vokonas, Pantel; Schwartz, Joel

    2011-05-01

    Studies show that ambient temperature and air pollution are associated with cardiovascular disease and that they may interact to affect cardiovascular events. However, few epidemiologic studies have examined mechanisms through which ambient temperature may influence cardiovascular function. The authors examined whether temperature was associated with heart rate variability (HRV) in a Boston, Massachusetts, study population and whether such associations were modified by ambient air pollution concentrations. The population was a cohort of 694 older men examined between 2000 and 2008. The authors fitted a mixed model to examine associations between temperature and air pollution and their interactions with repeated HRV measurements, adjusting for covariates selected a priori on the basis of their previous studies. Results showed that higher ambient temperature was associated with decreases in HRV measures (standard deviation of normal-to-normal intervals, low-frequency power, and high-frequency power) during the warm season but not during the cold season. These warm-season associations were significantly greater when ambient ozone levels were higher (>22.3 ppb) but did not differ according to levels of ambient fine (≤2.5 μm) particulate matter. The authors conclude that temperature and ozone, exposures to both of which are expected to increase with climate change, might act together to worsen cardiovascular health and/or precipitate cardiovascular events via autonomic nervous system dysfunction. PMID:21385834

  4. 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.

  5. Evaluation of Burning Test Rate Method for Flammable Solids to Increase air-Cargo Safety.

    PubMed

    Lukežič, Marjan; Marinšek, Marjan; Faganeli, Jadran

    2010-03-01

    This paper deals with a standard classification procedure for readily combustible solids and their assignment to the relevant packing groups according to international air-cargo legislation and regulations. The current International Air Transport Association and United Nations Orange Book regulations were used on chemically similar substances: hexamethylenetetramine and Dancook ignition briquettes, which are both assigned into the same Packing Group III. To critically evaluate the degree of hazard both chemicals present, a standard burning test rate as well as thermogravimetry, differential scanning calorimetry and evolved gas analysis measurements were performed. It was shown that relatively small changes in the chemical composition of the material may have essential influence on the package group determination. Taking into account all the facts collected in the experimental work, it was concluded that ignition briquettes will undergo spontaneous combustion if exposed to elevated temperatures and, from this point of view, represent higher risk than hexamethylenetetramine during air transportation. Therefore, ignition briquettes should be classified into Packing Group II. PMID:24061664

  6. 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

  7. Field observations of turbulent dissipation rate profiles immediately below the air-water interface

    NASA Astrophysics Data System (ADS)

    Wang, Binbin; Liao, Qian

    2016-06-01

    Near surface profiles of turbulence immediately below the air-water interface were measured with a free-floating Particle Image Velocimetry (PIV) system on Lake Michigan. The surface-following configuration allowed the system to measure the statistics of the aqueous-side turbulence in the topmost layer immediately below the water surface (z≈0˜15 cm, z points downward with 0 at the interface). Profiles of turbulent dissipation rate (ɛ) were investigated under a variety of wind and wave conditions. Various methods were applied to estimate the dissipation rate. Results suggest that these methods yield consistent dissipation rate profiles with reasonable scattering. In general, the dissipation rate decreases from the water surface following a power law relation in the top layer, ɛ˜z-0.7, i.e., the slope of the decrease was lower than that predicted by the wall turbulence theory, and the dissipation was considerably higher in the top layer for cases with higher wave ages. The measured dissipation rate profiles collapse when they were normalized with the wave speed, wave height, water-side friction velocity, and the wave age. This scaling suggests that the enhanced turbulence may be attributed to the additional source of turbulent kinetic energy (TKE) at the "skin layer" (likely due to micro-breaking), and its downward transport in the water column.

  8. 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.

  9. Effect of surfactants on the rate of growth of an air bubble by rectified diffusion.

    PubMed

    Lee, Judy; Kentish, Sandra; Ashokkumar, Muthupandian

    2005-08-01

    The rectified diffusion growth of a single air bubble levitated in an acoustic field (frequency = 22.35 kHz) in water and in aqueous solutions containing surfactants (sodium dodecyl sulfate and sodium dodecylbenzene sulfonate) was investigated. As reported by Crum (J. Acoust. Soc. Am. 1980, 68, 203), the presence of surfactants at the bubble/liquid interface enhanced the growth rate of the bubble by rectified diffusion. It is suggested in this paper that in addition to the effect of surfactants on the surface tension and interfacial resistance to mass transfer, the effect of surface rheological properties may also contribute to the cause of the enhancement observed in the bubble growth rate. PMID:16852840

  10. Effects of air oxidation on the dissolution rate of LWR spent fuel

    SciTech Connect

    Gray, W.J.; Thomas, L.E.; Einziger, R.E.

    1993-12-31

    Dissolution rates for air-oxidized spent fuel were measured in flowthrough tests where U concentrations were kept well below the solubility limit. Results from two types of specimens, separated grains and coarse particles, both in oxidized (U{sub 4}O{sub 9+x}) and unoxidized (UO{sub 2}) conditions indicated only minor effects of oxidation on the surface-area-normalized rates. Similar results were obtained for unirradiated specimens in three different oxidation states (UO{sub 2}, U{sub 3}O{sub 7}, and U{sub 3}O{sub 8}). These observations have important practical implications for disposal of spent fuel in a geologic repository as well as implications regarding the oxidative dissolution mechanism of UO{sub 2} fuel.

  11. 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…

  12. Biofiltration of air contaminated by styrene: Effect of nitrogen supply, gas flow rate, and inlet concentration

    SciTech Connect

    Jorio, H.; Bibeau, L.; Heitz, M.

    2000-05-01

    The biofiltration process is a promising technology for the treatment of dilute styrene emissions in air. The efficiency of this process is however strongly dependent upon various operational parameters such as the filter bed characteristics, nutrient supplies, input contaminant concentrations, and gas flow rates. The biofiltration of air containing styrene vapors was therefore investigated, employing a novel biomass filter material, in two identical but separate laboratory scale biofiltration units (units 1 and 2), both biofilters being initially inoculated with a microbial consortium. Each biofilter was irrigated with a nutrient solution supplying nitrogen in one of two forms; i.e., mainly as ammonia for unit 1 and exclusively as nitrate for unit 2. The experimental results have revealed that greater styrene elimination rates are achieved in the biofilter supplied with ammonia as the major nitrogen source in comparison to the lesser elimination performance obtained with the nitrate provided biofilter. However, in achieving the high styrene removal rates in the ammonia supplied biofilter, the excess of biomass accumulates on the filtering pellets and causes progressive clogging of the filter media. Furthermore, the effectiveness of nitrate supply as the sole nitrogen nutrient form, on reducing or controlling the biomass accumulation in the filter media in comparison to ammonia, could not be satisfactorily demonstrated because the two biofilters operated with very different styrene elimination capacities. The monitoring of the carbon dioxide concentration profile through both biofilters revealed that the ratio of carbon dioxide produced to the styrene removed was approximately 3/1, which confirms the complete biodegradation of removed styrene, given that some of the organic carbon consumed is also used for the microbial growth. The effects of the most important design parameters, namely styrene input concentrations and gas flow rates, were investigated for each

  13. Safety management of nuclear medicine personnel with visualisation of air dose rate.

    PubMed

    Kawase, S; Ohno, K; Nakamoto, Y; Miyatake, H

    2015-07-01

    Many people are anxious about radiation exposure for the reason that radiation cannot be seen. With the aim of devising a way for medical personnel to perform their medical duties without worry about radiation exposure, we attempted safety management using a system that displays the air dose of radiation in real time. Measurements were made in a lung ventilation scintigraphy examination room with the use of Xe-133. An SCI-type RI detector from Hamamatsu Photonics, which displays the air dose rate in real time, was used for the measurements. These radiation measurements were continued from the start to finish of the examination. The measurements were made in two locations, on the patient inhalation tube side and on the opposite side. Measurements were made on the patient tube side in 24 tests and on the opposite side in 12 tests. The maximum air dose rate was 3.7 ± 2.1 μSv/h on the patient tube side and 1.1 ± 0.5 μSv/h on the opposite side. Thus, the level on the opposite side was about 1/5 that of the tube side. To accurately perform lung ventilation scintigraphy, a medical worker needs to observe the patient's breathing status up close. Because of this, some medical workers are worried about radiation exposure during tests. The simplest way to reduce exposure would be to maintain a distance from the examination tube that is the source of radiation. The measurements in this study were made to encourage medical workers' recognition of this fact. Displaying specific numbers not only serves as basic data for managing staff operations, but is also thought to reassure workers through visualization. PMID:25889608

  14. 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.

  15. [Usefulness of Determining Acquisition Time by True Count Rate Measurement Method for Delivery 18F-FDG PET/CT].

    PubMed

    Miura, Shota; Odashima, Satoshi

    2016-03-01

    A stable quality of delivery 18F-fluoro-2-deoxy-D-glucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) requires suitable acquisition time, which can be obtained from an accurate true count of 18F-FDG. However, the true count is influenced by body mass index (BMI) and attenuation of 18F-FDG. In order to remove these influences, we have developed a new method (actual measurement method) to measure the actual true count rate based on sub-pubic thigh, which allows us to calculate a suitable acquisition time. In this study, we aimed to verify the acquisition count through our new method in terms of two categories: (1) the accuracy of acquisition count and (2) evaluation of clinical images using physical index. Our actual measurement method was designed to obtain suitable acquisition time through the following procedure. A true count rate of sub-pubic thigh was measured through detector of PET, and used as a standard true count rate. Finally, the obtained standard count rate was processed to acquisition time. This method was retrospectively applied to 150 patients, receiving 18F-FDG administration from 109.7 to 336.8 MBq, and whose body weight ranged from 37 to 95.4 kg. The accuracy of true count was evaluated by comparing relationships of true count, relative to BMI or to administered dose of 18F-FDG. The PET/CT images obtained by our actual measurement method were assessed using physical index. Our new method resulted in accurate true count, which was not influenced by either BMI or administered dose of 18F-FDG, as well as satisfied PET/CT images with recommended criteria of physical index in all patients. PMID:27000670

  16. Radiative and turbulent heating rates in the clear-air boundary layer

    NASA Astrophysics Data System (ADS)

    Savijärvi, Hannu

    2006-01-01

    The diurnal evolution of a clear-sky midlatitude summertime boundary layer (BL) was studied using a column model over smooth and homogeneous land, subject to weak, moderate, and strong winds. The high-resolution BL model (lowest point at 30 cm) was equipped with an adequate turbulence scheme and a narrow-band long-wave (LW) radiation scheme, the latter validated using data from the International Comparison of Radiation Codes in Climate Models (ICRCCM).In off-line ICRCCM experiments, ground emissivity ɛ < 1 led to extra LW cooling of air near the surface compared to ɛ = 1. However, much stronger LW cooling at heights of 1 3 m, and warming below 1 m, was obtained by setting the ground colder than air at screen height, a typical condition during clear nights. Conversely, a warm surface anomaly typical of sunny days leads to strong LW warming at 1 3 m, with LW cooling just above the ground. These ground temperature anomalies dominated the LW heating/cooling patterns at heights of up to 3 4 m, perhaps explaining controversies in the observed LW flux divergences close to the ground.Interactive model results indicate that the middle part of a windy clear-air nocturnal BL (NBL) is dominated by turbulent cooling, while the upper and lower NBL is dominated by LW cooling. Below about 1 m, a fourth layer is formed with LW warming and turbulent cooling, in agreement with the off-line experiments. When the surface winds fall below about 1 1.5 m s -1 LW cooling dominates in the whole NBL, except very near the surface. In these light wind conditions the Monin Obukhov theory should be revised to include radiative effects.In clear-air daytime conditions strong convective BL heating dominates over weak LW cooling except at 1 3 m heights where the cooler air absorbs the thermal emission of the hot ground. The subsequent LW warming of the superadiabatic surface layer appears to be strong enough to induce local turbulent cooling (despite the hot surface) in an 'hour glass' pattern

  17. The effects of outdoor air supply rate in an office on perceived air quality, sick building syndrome (SBS) symptoms and productivity.

    PubMed

    Wargocki, P; Wyon, D P; Sundell, J; Clausen, G; Fanger, P O

    2000-12-01

    Perceived air quality, Sick Building Syndrome (SBS) symptoms and productivity were studied in a normally furnished office space (108 m3) ventilated with an outdoor airflow of 3, 10 or 30 L/s per person, corresponding to an air change rate of 0.6, 2 or 6 h-1. The temperature of 22 degrees C, the relative humidity of 40% and all other environmental parameters remained unchanged. Five groups of six female subjects were each exposed to the three ventilation rates, one group and one ventilation rate at a time. Each exposure lasted 4.6 h and took place in the afternoon. Subjects were unaware of the intervention and remained thermally neutral by adjusting their clothing. They assessed perceived air quality and SBS symptoms at intervals, and performed simulated normal office work. Increasing ventilation decreased the percentage of subjects dissatisfied with the air quality (P < 0.002) and the intensity of odour (P < 0.02), and increased the perceived freshness of air (P < 0.05). It also decreased the sensation of dryness of mouth and throat (P < 0.0006), eased difficulty in thinking clearly (P < 0.001) and made subjects feel generally better (P < 0.0001). The performance of four simulated office tasks improved monotonically with increasing ventilation rates, and the effect reached formal significance in the case of text-typing (P < 0.03). For each two-fold increase in ventilation rate, performance improved on average by 1.7%. This study shows the benefits for health, comfort and productivity of ventilation at rates well above the minimum levels prescribed in existing standards and guidelines. It confirms the results of a previous study in the same office when the indoor air quality was improved by decreasing the pollution load while the ventilation remained unchanged. PMID:11089327

  18. Hydrocarbon Observations and Ozone Production Rates in Western Houston During the Texas 2000 Air Quality Study

    SciTech Connect

    Berkowitz, Carl M.; Spicer, Chet W.; Doskey, Paul V.

    2005-06-01

    Measurements of total non-methane hydrocarbon in whole air canisters collected from the top of a skyscraper on the western edge of Houston, Texas are summarized with an emphasis on samples collected during the passage of plumes of O{sub 3} and the associated rapid increase in the mixing ratio of this species. The back-trajectories associated with these events showed a pronounced deceleration of air parcels over central and western Houston and were not necessarily associated with direct passage over the petrochemical plants located in the heavily industrialized eastern part of Houston. As a result of the time these air parcels spent over the central and western parts of Houston, their VOC mix and associated chemical production rates were expected to differ from similar observations made over eastern Houston from aircraft sampling at low altitudes. Although periods of high O{sub 3} in the western part of the city were closely associated with light alkenes, these same observations show isoprene to make a significant contribution to the total VOC reactivity in the early afternoon (the start of peak photochemical activity) in contrast to observations made east of our sampling site that found the reactivity to be dominated by anthropogenic species. By initializing a 0-dimensional chemical kinetic model with observations made at the Williams Tower, we find that the ozone production efficiency scaled linearly to the ratio of total hydrocarbons and NO{sub x}, with an average OPE of 7.2, ranging from 2.3 to 16.9; these values are smaller than those reported in eastern Houston, suggesting a strong gradient in photochemical productivity across the city.

  19. Indoor Air Pollution, Nighttime Heart Rate Variability and Coffee Consumption among Convenient Store Workers

    PubMed Central

    Chuang, Kai-Jen; Chuang, Hsiao-Chi; Lin, Lian-Yu

    2013-01-01

    Background The association between ambient air pollution and heart rate variability (HRV) has been well-documented. Little is known about the association of HRV at night with indoor air pollution and coffee consumption. The aim of this study was to investigate the association of HRV indices with indoor air pollution, working time and coffee consumption. Methods We recruited 60 young healthy convenient store workers to monitor indoor PM2.5 (particulate matter with an aerodynamic diameter ≤ 2.5 µm) exposures, coffee consumption (yes vs. no) and HRV indices during daytime (0700–1500 hours) and nighttime (2300-0700 hours). We used linear mixed effects models to assess the associations of HRV indices with indoor PM2.5 exposures and coffee consumption. Results We observed the inverse association between indoor PM2.5 exposures and HRV indices, with a decrease in all HRV indices with increased indoor PM2.5 exposures. However, the decrease was most pronounced during nighttime, where a 1 interquartile range (IQR) increase in indoor PM2.5 at 4-hr time-weighted moving average was associated with a change of −4.78% 5-min standard deviation (SD) of normal-to-normal intervals for 5-min segment (SDNN) and −3.23% 5-min square root of the mean squared differences of successive intervals for 5-min segment (r-MSSD). Effects of indoor PM2.5 were lowest for participants with coffee consumption during daytime. Conclusions Indoor PM2.5 exposures were associated with decreased 5-min SDNN and 5-min r-MSSD, especially during nighttime. The effect of indoor PM2.5 on HRV indices may be modified by coffee consumption in young healthy convenient store workers. PMID:24312680

  20. 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.

  1. An experimental investigation on the effects of surface gravity waves on the water evaporation rate in different air flow regimes

    NASA Astrophysics Data System (ADS)

    Jodat, Amin; Moghiman, Mohammad; Shirkhani, Golshad

    2013-12-01

    Estimating rate of evaporation from undisturbed water surfaces to moving and quiet air has been the topic a vast number of research activities. The obvious presence of various shapes of gravity waves on the water body surfaces was the motivation of this experimental investigation. In this investigation experimental measurements have been done to quantify evaporation rate from wavy water surfaces in free, mixed and forced convection regimes. The effects of a wide range of surface gravity waves from low steepness, round shaped crest with slow celerity, to steep and very slight spilling crest waves, on the water evaporation rate have been investigated. A wide range of was achieved by applying different air flow velocities on a large heated wave flume equipped with a wind tunnel. Results reveal that wave motion on the water surface increase the rate of evaporation for all air flow regimes. For free convection, due to the effect of wave motion for pumping rotational airflows at the wave troughs and the dominant effect of natural convection for the air flow advection, the maximum evaporation increment percentage from wavy water surface is about 70 %. For mixed and forced convection, water evaporation rate increment is more sensitive to the air flow velocity for the appearance of very slight spilling on the steep wave crests and the leeward air flow structures.

  2. Effects of oblique air flow on burning rates of square ethanol pool fires.

    PubMed

    Tao, Changfa; He, Yaping; Li, Yuan; Wang, Xishi

    2013-09-15

    The effects of downward airflow on the burning rate and/or burning intensity of square alcohol pool fires for different airflow speeds and directions have been studied experimentally in an inclined wind tunnel. An interesting flame-wrapping phenomenon, caused by impingement of air flow, was observed. The mass burning intensity was found to increase with the airflow speed and the impinging angle. The fuel pan rim temperatures were also measured to study the effect of wind direction and speed on heat transfer from the flame to the fuel source. A model based on heat transfer analysis was developed to correlate the burning intensity with the pan rim characteristic temperature. A good correlation was established between the model results and the experimental results. PMID:23811377

  3. Effects of different data-editing methods on trends in race-specific preterm delivery rates, United States, 1990-2002.

    PubMed

    Qin, Cheng; Dietz, Patricia M; England, Lucinda J; Martin, Joyce A; Callaghan, William M

    2007-09-01

    In recent years, national vital statistics data indicate that the US preterm delivery rate has decreased among African Americans and increased among whites. These trends in preterm delivery rates may have been affected, in part, by improvements in the accuracy of gestational age reporting on birth certificates. Several data-editing methods have been developed with the intention of reducing the percentage of records with misclassified gestational age. We explored whether three data-editing methods yielded different trends in preterm delivery for years 1990-2002 among US non-Hispanic white and non-Hispanic African American singleton livebirths. Using National Center for Health Statistics (NCHS) public-use data, we assessed two published methods for editing gestational age, one by Alexander et al. and the other by Zhang and Bowes (Zhang/Bowes). We also assessed a third method that substitutes the clinical estimate (CE) of gestational age when the NCHS last menstrual period (LMP)-based estimate differs from the CE by more than 2 weeks (the LMP/CE method). The percentage of records excluded and/or reclassified by each method was calculated for years 1990, 1996 and 2002. Gestational age-specific birthweight distributions were plotted by race for each method. Preterm delivery rates were calculated and compared by method of editing over time. The percentage of records excluded or reclassified declined from 1990 to 2002 regardless of the method applied. For infants at 28-33 weeks' gestation using the NCHS edited data, birthweight distributions were bimodal, with the second (right-sided) mode showing a mean birthweight consistent with that of term infants. The second mode was less pronounced using the Alexander et al. and the Zhang/Bowes methods, and was not present when the LMP/CE method was used. From 1990 to 2002, preterm delivery rates increased for non-Hispanic whites regardless of method (range 21.3-31.3%). Preterm delivery rates increased slightly for non

  4. 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.

  5. A comparison of the tissue oxygenation achieved using different oxygen delivery devices and flow rates.

    PubMed

    2016-03-01

    Consistent with the Committee on Publication Ethics guidelines, we the above authors are initiating a partial retraction of our paper: Blake DF, Naidoo P, Brown LH, Young DA, Lippmann J: A comparison of the tissue oxygenation achieved using different oxygen delivery devices and flow rates. Diving Hyperb Med. 2015;45:79-83. We wish to make the following statement: "The authors voluntarily retract aspects of this article after discovering a critical error associated with the instrumentation used in the study, namely the fitting of incorrect sensor membranes on the electrodes of the transcutaneous oximetry device used in the study. This resulted in transcutaneous oxygen tension (PtcO₂) measurements that were consistently lower than those that would be recorded with the correct electrode membranes in place. This measurement error was consistent across all arms of the study. This non-differential information error would have created a bias toward the null hypothesis. Therefore, whilst the absolute values for the data were incorrect, the direction and implications of the significant associations reported in this study are unchanged." PMID:27044467

  6. 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. PMID:11282319

  7. The association of particulate air metal concentrations with heart rate variability.

    PubMed Central

    Magari, Shannon R; Schwartz, Joel; Williams, Paige L; Hauser, Russ; Smith, Thomas J; Christiani, David C

    2002-01-01

    Numerous studies show an association between particulate air pollution and adverse health effects. Particulate matter is a complex mixture of elemental carbon, ammonium, sulfates, nitrates, organic components, and metals. The mechanisms of action of particulate matter less than or equal to 2.5 micro m in mean aerodynamic diameter (PM(2.5)), as well as the constituents responsible for the observed cardiopulmonary health effects, have not been identified. In this study we focused on the association between the metallic component of PM(2.5) and cardiac autonomic function based on standard heart rate variability (HRV) measures in an epidemiologic study of boilermakers. Thirty-nine male boilermakers were monitored throughout a work shift. Each subject wore an ambulatory electrocardiogram (Holter) monitor and a personal monitor to measure PM(2.5). We used mixed-effects models to regress heart rate and SDNN index (standard deviation of the normal-to-normal) on PM(2.5) and six metals (vanadium, nickel, chromium, lead, copper, and manganese). There were statistically significant mean increases in the SDNN index of 11.30 msec and 3.98 msec for every 1 micro g/m(3) increase in the lead and vanadium concentrations, respectively, after adjusting for mean heart rate, age, and smoking status. Small changes in mean heart rate were seen with all exposure metrics. The results of this study suggest an association between exposure to airborne metals and significant alterations in cardiac autonomic function. These results extend our understanding of the adverse health effects of the metals component of ambient PM(2.5). PMID:12204821

  8. Childhood cancer incidence rates and hazardous air pollutants in California: an exploratory analysis.

    PubMed Central

    Reynolds, Peggy; Von Behren, Julie; Gunier, Robert B; Goldberg, Debbie E; Hertz, Andrew; Smith, Daniel F

    2003-01-01

    Hazardous air pollutants (HAPs) are compounds shown to cause cancer or other adverse health effects. We analyzed population-based childhood cancer incidence rates in California (USA) from 1988 to 1994, by HAP exposure scores, for all California census tracts. For each census tract, we calculated exposure scores by combining cancer potency factors with outdoor HAP concentrations modeled by the U.S. Environmental Protection Agency. We evaluated the relationship between childhood cancer rates and exposure scores for 25 potentially carcinogenic HAPs emitted from mobile, area, and point sources and from all sources combined. Our study period saw 7,143 newly diagnosed cancer cases in California; of these, 6,989 (97.8%) could be assigned to census tracts and included in our analysis. Using Poisson regression, we estimated rate ratios (RRs) adjusted for age, race/ethnicity, and sex. We found little evidence for elevated cancer RRs for all sites or for gliomas among children living in high-ranking combined-source exposure areas. We found elevated RRs and a significant trend with increasing exposure level for childhood leukemia in tracts ranked highest for exposure to the combined group of 25 HAPs (RR = 1.21; 95% confidence interval, 1.03, 1.42) and in tracts ranked highest for point-source HAP exposure (RR = 1.32; 95% confidence interval, 1.11, 1.57). Our findings suggest an association between increased childhood leukemia rates and high HAP exposure, but studies involving more comprehensive exposure assessment and individual-level exposure data will be important for elucidating this relationship. PMID:12676632

  9. 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....

  10. 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'.

  11. 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)...

  12. 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. PMID:24401556

  13. 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.

  14. Uneven Futures of Human Lifespans: Reckonings from Gompertz Mortality Rates, Climate Change, and Air Pollution

    PubMed Central

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

    2014-01-01

    The past 200 years have enabled remarkable increases in human lifespans thru improvements of 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 Jean 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 C cohorts would require 50% slower mortality rate accelerations, which would be a fundamental change in the rate of human aging. Looking into the 21st C, 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 to favor the spread of pathogens. We anticipate continuing socio-economic disparities of life expectancy. PMID:24401556

  15. 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...

  16. The influence of surface sorption and air flow rate on phthalate emissions from vinyl flooring: Measurement and modeling

    NASA Astrophysics Data System (ADS)

    Liang, Yirui; Xu, Ying

    2015-02-01

    This study investigated the influences of surface sorption and air flow rate on the emission of phthalates from building materials. Controlled tests were conducted in specially designed stainless steel and wood chambers, and the steady-state concentration in the stainless steel chamber was about 2-3 times higher than that in the wood chamber for di(2-ethylhexyl) phthalate (DEHP) and diisononyl phthalate (DINP). The emission rate of phthalates increased in the wood chamber due to the diffusion mass flow through the chamber wall (i.e., surface absorption). The adsorption isotherm of phthalates on the stainless steel surface and the absorption parameters (i.e., diffusion and partition coefficients) of phthalates on the wood surface were determined experimentally, and the values were comparable to those in the literature. The equilibration time scale for phthalates absorbed to the sink reservoir in actual indoor environments was estimated and can be substantial (approximately 80 years), indicating that surface absorption may continuously drive phthalates from their indoor sources to various sinks and thus significantly increase the emission rate of phthalates. The gas-phase concentration of DEHP was measured in two stainless steel chambers operated at flow rates of 300 mL/min and 3000 mL/min, respectively, which were both adjusted to 1000 mL/min after steady state was reached. The gas-phase concentration of DEHP in the chamber was very sensitive to the chamber air flow rate, and higher air flow rates resulted in lower concentration levels. However, the increased emission rate compensated for the dilution in the gas phase and made the DEHP concentration not drop substantially with an increase in the air flow rate. Independently measured or calculated parameters were used to validate a semi-volatile organic compounds (SVOCs) emission model that included absorptive surfaces and for a range of air flow rates, with excellent agreement between the model predictions and the

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

    NASA Astrophysics Data System (ADS)

    Kessler, C.; Allisy-Roberts, P. J.; Selbach, H. J.

    2015-01-01

    An indirect comparison of the standards for reference air kerma rate (RAKR) for 192Ir high dose rate (HDR) brachytherapy sources of the Physikalisch-Technische Bundesanstalt (PTB), Germany, and of the Bureau International des Poids et Mesures (BIPM) was carried out at the PTB in September 2011. The comparison result, based on the calibration coefficients for a transfer standard and expressed as a ratio of the PTB and the BIPM standards for reference air kerma rate, is 1.0003 with a combined standard uncertainty of 0.0099. 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).

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

    NASA Astrophysics Data System (ADS)

    Kessler, C.; Downton, B.; Mainegra-Hing, E.

    2015-01-01

    An indirect comparison of the standards for reference air kerma rate for 192Ir high dose rate (HDR) brachytherapy sources of the National Research Council (NRC), Canada, and of the Bureau International des Poids et Mesures (BIPM) was carried out at the NRC in August 2014. The comparison result, based on the calibration coefficients for a transfer standard and expressed as a ratio of the NRC and the BIPM standards for reference air kerma rate, is 0.9966 with a combined standard uncertainty of 0.0050. 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).

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

    NASA Astrophysics Data System (ADS)

    Kessler, C.; Kurosawa, T.; Mikamoto, T.

    2016-01-01

    An indirect comparison of the standards for reference air kerma rate for 192Ir high dose rate (HDR) brachytherapy sources of the National Metrology Institute of Japan (AIST-NMIJ), Japan, and of the Bureau International des Poids et Mesures (BIPM) was carried out at the Japan Radioisotope Association (JRIA) in April 2015. The comparison result, based on the calibration coefficients for a transfer standard and expressed as a ratio of the NMIJ and the BIPM standards for reference air kerma rate, is 1.0036 with a combined standard uncertainty of 0.0054. 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).

  20. Impact of alternative reimbursement strategies in the new cooperative medical scheme on caesarean delivery rates: a mixed-method study in rural China

    PubMed Central

    2012-01-01

    Background The rate of caesarean delivery (CD) in rural China has been rapidly increasing in recent decades. Due to the exorbitant costs associated with CD, paying for this expensive procedure is often a great challenge for the majority of rural families. Since 2003, the Chinese government has re-established the New Cooperative Medical Scheme (NCMS), aimed to improve the access of essential healthcare to rural residents and reduce financial burden owing to high out of pocket payments. This paper seeks to test the hypothesis that NCMS may provide service users and providers with financial incentives to select CD. It also assesses the effect of different health insurance reimbursement strategies of NCMS on CD rates in rural China. Methods Mixed quantitative and qualitative methods were adopted for data collection. Two cross-sectional household surveys were conducted with women having babies delivered in 2006 and 2009; 2326 and 1515 women, respectively, from the study sites were interviewed using structured questionnaires, to collect demographic and socio-economic data, maternal and child care characteristics and health-related expenditures. Focus group discussions (FGDs) and in-depth key informant interviews (KIIs) were undertaken with policy makers, health managers, providers and mothers to understand their perceptions of the influence of NCMS on the choices of delivery mode. Results The CD rates in the two study counties were 46.0 percent and 64.7 percent in 2006, increasing to 63.6 percent and 82.1 percent, respectively, in 2009. The study found that decisions on the selection of CD largely came from the pregnant women. Logistic regression analysis, after adjusting for socio-economic, maternal and fetal characteristics, did not indicate a significant effect of either proportional reimbursement or fixed amount reimbursement on the choice of CD for both study years. Interviews with stakeholders reflected that different reimbursable rates for CD and vaginal

  1. 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.

  2. 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

    2014-11-01

    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 and

  3. 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

  4. 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. PMID:26804182

  5. 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.

  6. Impact of Janani Suraksha Yojana on institutional delivery rate and maternal morbidity and mortality: an observational study in India.

    PubMed

    Gupta, Sanjeev K; Pal, Dinesh K; Tiwari, Rajesh; Garg, Rajesh; Shrivastava, Ashish K; Sarawagi, Radha; Patil, Rajkumar; Agarwal, Lokesh; Gupta, Prashant; Lahariya, Chandrakant

    2012-12-01

    The Government of India initiated a cash incentive scheme--Janani Suraksha Yojana (JSY)--to promote institutional deliveries with an aim to reduce maternal mortality ratio (MMR). An observational study was conducted in a tertiary-care hospital of Madhya Pradesh, India, before and after implementation of JSY, with a sample of women presenting for institutional delivery. The objectives of this study were to: (i) determine the total number of institutional deliveries before and after implementation of JSY, (ii) determine the MMR, and (iii) compare factors associated with maternal mortality and morbidity. The data were analyzed for two years before implementation of JSY (2003-2005) and compared with two years following implementation of JSY (2005-2007). Overall, institutional deliveries increased by 42.6% after implementation, including those among rural, illiterate and primary-literate persons of lower socioeconomic strata. The main causes of maternal mortality were eclampsia, pre-eclampsia and severe anaemia both before and after implementation of JSY. Anaemia was the most common morbidity factor observed in this study. Among those who had institutional deliveries, there were significant increases in cases of eclampsia, pre-eclampsia, polyhydramnios, oligohydramnios, antepartum haemorrhage (APH), postpartum haemorrhage (PPH), and malaria after implementation of JSY. The scheme appeared to increase institutional delivery by at-risk mothers, which has the potential to reduce maternal morbidity and mortality, improve child survival, and ensure equity in maternal healthcare in India. The lessons from this study and other available sources should be utilized to improve the performance and implementation of JSY scheme in India. PMID:23304913

  7. Comparison of success rate of intubation through Air-Q with ILMA using two different endotracheal tubes

    PubMed Central

    Malhotra, SK; Bharath, KV; Saini, Vikas

    2016-01-01

    Background and Aims: Air-Q™ is a newly introduced airway device, which can be used to facilitate endotracheal intubation. The primary aim of this study was to assess whether use of two different endotracheal tubes (ETTs) (standard polyvinyl chloride [PVC] and reinforced PVC) increases the success rate of blind intubation through Air-Q™ (Group Q) when compared with intubating laryngeal mask airway (ILMA- Fastrach™) keeping ILMA as control (Group I). Methods: One hundred and twenty patients aged between 18 and 60 years with American Society of Anesthesiologists physical status I-II, undergoing elective surgery under general anaesthesia, were enrolled into this prospective, randomised, case–control study to compare the success rate of tracheal intubation between ILMA (Fastrach™) and Air-Q™ intubating laryngeal airway. Those patients with anticipated difficult airway were excluded from the study. All the recruited patients completed the study. Reinforced PVC ETT was used in both airway devices to secure intubation. Since standard PVC tube is recommended for use in Air-Q, when first intubation attempt failed, second or third attempt was made with standard PVC ETT. Total of three attempts were made for each procedure: Whereas in ILMA group, only reinforced tube was used in all three attempts. Results: The overall success rate after three attempts was more with Air-Q (96.6%) in our study compared with ILMA (91.6%) but no significant difference was seen between the groups (P = 0.43). Conclusion: The present study shows that when intubation with reinforced tube fails, the success rate with use of conventional PVC tube is more with Air-Q when compared with ILMA. PMID:27141106

  8. The vascular actions of insulin control its delivery to muscle and regulate the rate-limiting step in skeletal muscle insulin action

    PubMed Central

    Barrett, EJ; Eggleston, EM; Inyard, AC; Wang, H; Li, G; Chai, W; Liu, Z

    2009-01-01

    Evidence suggests that insulin delivery to skeletal muscle interstitium is the rate-limiting step in insulin-stimulated muscle glucose uptake and that this process is impaired by insulin resistance. In this review we examine the basis for the hypothesis that insulin acts on the vasculature at three discrete steps to enhance its own delivery to muscle: (1) relaxation of resistance vessels to increase total blood flow; (2) relaxation of pre-capillary arterioles to increase the microvascular exchange surface perfused within skeletal muscle (microvascular recruitment); and (3) the trans-endothelial transport (TET) of insulin. Insulin can relax resistance vessels and increase blood flow to skeletal muscle. However, there is controversy as to whether this occurs at physiological concentrations of, and exposure times to, insulin. The microvasculature is recruited more quickly and at lower insulin concentrations than are needed to increase total blood flow, a finding consistent with a physiological role for insulin in muscle insulin delivery. Microvascular recruitment is impaired by obesity, diabetes and nitric oxide synthase inhibitors. Insulin TET is a third potential site for regulating insulin delivery. This is underscored by the consistent finding that steady-state insulin concentrations in plasma are approximately twice those in muscle interstitium. Recent in vivo and in vitro findings suggest that insulin traverses the vascular endothelium via a trans-cellular, receptor-mediated pathway, and emerging data indicate that insulin acts on the endothelium to facilitate its own TET. Thus, muscle insulin delivery, which is rate-limiting for its metabolic action, is itself regulated by insulin at multiple steps. These findings highlight the need to further understand the role of the vascular actions of insulin in metabolic regulation. PMID:19283361

  9. 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...

  10. 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,...

  11. 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...

  12. 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...

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

    PubMed

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

    2010-02-23

    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 (SO(2)) 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 SO(2) >200 ppb and acid aerosol (n=19); chronic exposure to SO(2) ≥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 SO(2) 100-250 ppb and concentration of respirable particles of diameter ≥2.5 μ (PM(2.5)) >500 μg/m(3). 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

  14. The amphibious fish Kryptolebias marmoratus uses different strategies to maintain oxygen delivery during aquatic hypoxia and air exposure.

    PubMed

    Turko, Andy J; Robertson, Cayleih E; Bianchini, Kristin; Freeman, Megan; Wright, Patricia A

    2014-11-15

    Despite the abundance of oxygen in atmospheric air relative to water, the initial loss of respiratory surface area and accumulation of carbon dioxide in the blood of amphibious fishes during emersion may result in hypoxemia. Given that the ability to respond to low oxygen conditions predates the vertebrate invasion of land, we hypothesized that amphibious fishes maintain O2 uptake and transport while emersed by mounting a co-opted hypoxia response. We acclimated the amphibious fish Kryptolebias marmoratus, which are able to remain active for weeks in both air and water, for 7 days to normoxic brackish water (15‰, ~21kPa O2; control), aquatic hypoxia (~3.6kPa), normoxic air (~21 kPa) or aerial hypoxia (~13.6kPa). Angiogenesis in the skin and bucco-opercular chamber was pronounced in air- versus water-acclimated fish, but not in response to hypoxia. Aquatic hypoxia increased the O2-carrying capacity of blood via a large (40%) increase in red blood cell density and a small increase in the affinity of hemoglobin for O2 (P50 decreased 11%). In contrast, air exposure increased the hemoglobin O2 affinity (decreased P50) by 25% without affecting the number of red blood cells. Acclimation to aerial hypoxia both increased the O2-carrying capacity and decreased the hemoglobin O2 affinity. These results suggest that O2 transport is regulated both by O2 availability and also, independently, by air exposure. The ability of the hematological system to respond to air exposure independent of O2 availability may allow extant amphibious fishes, and may also have allowed primitive tetrapods to cope with the complex challenges of aerial respiration during the invasion of land. PMID:25267849

  15. 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

  16. 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). PMID:25246092

  17. 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

  18. 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.

  19. [Effects of air pollution on stillbirth rates in an industrial town].

    PubMed

    Dimitriev, D A

    2000-01-01

    The impact of seasonal variations in ambient air pollution with some compounds (suspended matters, sulphur dioxide, carbon oxide, nitrogen dioxide) on stillbirth was studied. Changes in the concentration of the studied pollutants were found to affect stillbirth. PMID:11030098

  20. 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)

  1. Impact of Blow/Fill/Seal process variables in determining rate of vial contamination by air dispersed microorganisms.

    PubMed

    Leo, Frank; Poisson, Patrick; Sinclair, Colin S; Tallentire, Alan

    2005-01-01

    Controlled challenges of air dispersed spores of Bacillus subtilis NCIMB 8649 have been generated in a custom-built challenge room housing a Blow/Fill/Seal machine filling filter-sterilized trypticase soy broth into 5.5 cm3 low density polyethylene vials. The effects on the rate of vial contamination of systematic changes in the process variables, rate of provision of ballooning air, delay in the application of mould vacuum and duration of transfer of the open vial, have been examined. Overall, the findings show that the conditions of vial formation can affect appreciably the rate of vial contamination from airborne spores. The indications are that heat lethality, associated with the elevated temperature required for polymer extrusion and vial formation, has a role in determining such contamination. PMID:16316067

  2. Measurement of HO{sub x}{center_dot} 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 ({center_dot}OH and HO{sub 2} {center_dot}) 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 HO{sub x}{center_dot} production rate in indoor air caused by radon decay. Average HO{sub x}{center_dot} production rate was found to be (4.31{plus_minus}0.07) {times} 10{sup 5} HO{sub x}{center_dot} per Rn decay per second (Bq) 3.4 to 55.0% at 22C. This work provided G{sub (HO{sub x}{center_dot})}-value, 7.86{plus_minus}0.13 No./100 eV in air by directly measuring [HO{sub x}{center_dot}] formed from the radiolysis procedure. This G value implies that HO{sub x}{center_dot} 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 HO{sub x}{center_dot} production rate and relative humidity. A laser-induced fluorescence (LIF) system has been used for {center_dot}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 {center_dot}OH produced from the photolysis of O{sub 3}/H{sub 2}O.

  3. 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.

  4. 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. PMID:24698118

  5. Transdermal drug delivery

    PubMed Central

    Prausnitz, Mark R.; Langer, Robert

    2009-01-01

    Transdermal drug delivery has made an important contribution to medical practice, but has yet to fully achieve its potential as an alternative to oral delivery and hypodermic injections. First-generation transdermal delivery systems have continued their steady increase in clinical use for delivery of small, lipophilic, low-dose drugs. Second-generation delivery systems using chemical enhancers, non-cavitational ultrasound and iontophoresis have also resulted in clinical products; the ability of iontophoresis to control delivery rates in real time provides added functionality. Third-generation delivery systems target their effects to skin’s barrier layer of stratum corneum using microneedles, thermal ablation, microdermabrasion, electroporation and cavitational ultrasound. Microneedles and thermal ablation are currently progressing through clinical trials for delivery of macromolecules and vaccines, such as insulin, parathyroid hormone and influenza vaccine. Using these novel second- and third-generation enhancement strategies, transdermal delivery is poised to significantly increase impact on medicine. PMID:18997767

  6. Effect of ambient air pollution on daily mortality rates in Guangzhou, China

    NASA Astrophysics Data System (ADS)

    Yu, Ignatius Tak Sun; Zhang, Yong hui; San Tam, Wilson Wai; Yan, Qing Hua; Xu, Yan jun; Xun, Xiao jun; Wu, Wei; Ma, Wen Jun; Tian, Lin Wei; Tse, Lap Ah; Lao, Xiang Qian

    2012-01-01

    We aimed to investigate the effects of ambient air pollutants on daily mortality in a relatively stable and homogeneous population in Guangzhou, China. Daily mortality, air pollution, and weather data between 2006 and 2009 were collected. The generalized additive model with poison regression was used to estimate the excessive risks (ERs) of air pollutants (PM 10, SO 2, and NO 2) on total, cardiovascular and respiratory mortality. The effects of lag0-1 were the greatest for total non-accidental and cardiovascular deaths. The increments of 10 μg m -3 in SO 2, NO 2, and PM 10 were associated with ERs of 1.54% (95%CI: 1.03-2.06%), 1.42% (95%CI: 1.06-1.78%), and 1.26% (95%CI: 0.86-1.66%) respectively for total non-accidental deaths, and 2.28% (95%CI: 1.40-3.16%), 1.81% (95%CI: 1.20-2.41%), and 1.79% (95%CI: 1.11-2.47%) respectively for cardiovascular deaths. For persons who died from respiratory disease, however, the maximum effects occurred at lag0. The ERs for SO 2, NO 2, and PM 10 were 1.36% (95%CI: 0.23-2.50%), 1.47% (95%CI: 0.66-2.29%) and 0.93% (95%CI: 0.03-1.83%), respectively. The effects of the three air pollutants on mortality were stronger in elderly and in women. The ERs in the present study were higher than those reported in Europe, the U.S., and most other Asian cities. Our findings show relatively higher ERs of daily mortality by ambient air pollutants in the center of Guangzhou, China, compared with estimates in other cities. Further studies with accurate exposure measurement among homogeneous population are needed to evaluate the precise magnitudes of the effects of the air pollutants.

  7. 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

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

    PubMed Central

    Wang, Kaicun; Zhou, Chunlüe

    2015-01-01

    Global analyses of surface mean air temperature (Tm) 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 Tm. Existing global analyses calculate Tm 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 Tm 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. PMID:26198976

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

    NASA Astrophysics Data System (ADS)

    Wang, Kaicun; Zhou, Chunlüe

    2015-07-01

    Global analyses of surface mean air temperature (Tm) 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 Tm. Existing global analyses calculate Tm 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 Tm 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.

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

    NASA Astrophysics Data System (ADS)

    Wang, Kaicun; Zhou, Chunlüe

    2016-04-01

    Global analyses of surface mean air temperature (Tm) 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 depends on the calculation methods of Tm. Existing global analyses calculated Tm 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 Tm 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. Regional Contrasts of the Warming Rate over Land Significantly Depend on the Calculation Methods of Mean Air Temperature.

    PubMed

    Wang, Kaicun; Zhou, Chunlüe

    2015-01-01

    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. PMID:26198976

  12. 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

  13. 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...

  14. 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.

  15. Lower responsiveness of canopy evapotranspiration rate than of leaf stomatal conductance to open-air CO2 elevation in rice.

    PubMed

    Shimono, Hiroyuki; Nakamura, Hirofumi; Hasegawa, Toshihiro; Okada, Masumi

    2013-08-01

    An elevated atmospheric CO2 concentration ([CO2 ]) can reduce stomatal conductance of leaves for most plant species, including rice (Oryza sativa L.). However, few studies have quantified seasonal changes in the effects of elevated [CO2 ] on canopy evapotranspiration, which integrates the response of stomatal conductance of individual leaves with other responses, such as leaf area expansion, changes in leaf surface temperature, and changes in developmental stages, in field conditions. We conducted a field experiment to measure seasonal changes in stomatal conductance of the uppermost leaves and in the evapotranspiration, transpiration, and evaporation rates using a lysimeter method. The study was conducted for flooded rice under open-air CO2 elevation. Stomatal conductance decreased by 27% under elevated [CO2 ], averaged throughout the growing season, and evapotranspiration decreased by an average of 5% during the same period. The decrease in daily evapotranspiration caused by elevated [CO2 ] was more significantly correlated with air temperature and leaf area index (LAI) rather than with other parameters of solar radiation, days after transplanting, vapor-pressure deficit and FAO reference evapotranspiration. This indicates that higher air temperatures, within the range from 16 to 27 °C, and a larger LAI, within the range from 0 to 4 m(2)  m(-2) , can increase the magnitude of the decrease in evapotranspiration rate caused by elevated [CO2 ]. The crop coefficient (i.e. the evapotranspiration rate divided by the FAO reference evapotranspiration rate) was 1.24 at ambient [CO2 ] and 1.17 at elevated [CO2 ]. This study provides the first direct measurement of the effects of elevated [CO2 ] on rice canopy evapotranspiration under open-air conditions using the lysimeter method, and the results will improve future predictions of water use in rice fields. PMID:23564676

  16. Indoor air exposure to coal and wood combustion emissions associated with a high lung cancer rate in Xuan Wei, China

    SciTech Connect

    Mumford, J.L.; Chapman, R.S.; Harris, D.B.; He, X.Z.; Cac, S.R.

    1989-01-01

    Residents of Xuan Wei County in China have unusually high lung cancer mortality that cannot be attributed to tobacco use or occupational exposure. They are exposed to smoke from unvented, open pit coal or wood fires (often used for cooking and heating). The variation in lung cancer rates among communes within the county suggests that indoor combustion of smoky coal may be the prime determinant of lung cancer. To characterize the air in Xuan Wei homes, samples of the air particles and semivolatile organic compounds were collected from homes located in two communes; one commune has a high rate of lung cancer, and the other has a low rate. Samples collected in the commune where the lung cancer rate is high and where smoky coal is the predominant fuel contained high concentrations of small particles with high organic content; organic extracts of these samples were mutagenic. Samples from homes in the wood-burning commune, which has a low rate of lung cancer, consisted mostly of larger particles of lower organic content and mutagenicity. The smoky coal sample was a mouse skin carcinogen and was a more potent initiator of skin tumors in comparison to the wood or smokeless coal sample.

  17. Indoor air exposure to coal and wood combustion emissions associated with a high lung cancer rate in Xuan Wei, China

    SciTech Connect

    Mumford, J.L.; Chapman, R.S.; Harris, D.B. ); He, X.Z.; Cao, S.R.; Xian, Y.L.; Li, X.M. )

    1989-01-01

    Residents of Xuan Wei County in China have unusually high lung cancer mortality that cannot be attributed to tobacco use or occupational exposure. They are exposed to smoke from unvented, open pit coal or wood fires (often used for cooking and heating). The variation in lung cancer rates among communes within the county suggests that indoor combustion of smoky coal may be the prime determinant of lung cancer. To characterize the air in Xuan Wei homes, samples of air particles and semivolatile organic compounds were collected from homes located in two communes; one commune has a high rate of lung cancer, and the other has a low rate. Samples collected in the commune where the lung cancer rate is high and where smoky coal is the predominant fuel contained high concentrations of small particles with high organic content; organic extracts of these samples were mutagenic. Samples from homes in the wood-burning commune, which has a low rate of lung cancer, consisted mostly of larger particles of lower organic content and mutagenicity. The smoky coal sample was a mouse skin carcinogen and was a more potent initiator of skin tumors in comparison to the wood or smokeless coal sample.

  18. 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 ...

  19. Cave air and hydrological controls on prior calcite precipitation and stalagmite growth rates: Implications for palaeoclimate reconstructions using speleothems

    NASA Astrophysics Data System (ADS)

    Sherwin, Catherine M.; Baldini, James U. L.

    2011-07-01

    Hourly resolved cave air P and cave drip water hydrochemical data illustrate that calcite deposition on stalagmites can be modulated by prior calcite precipitation (PCP) on extremely short timescales. A very clear second-order covariation between cave air P and drip water Ca 2+ concentrations during the winter months demonstrates the effects of degassing-induced PCP on drip water chemistry. Estimating the strength of the cave air P control on PCP is possible because the PCP signal is so clear; at our drip site a one ppm shift in Ca 2+ concentrations requires a P shift of between 333 and 667 ppm. This value will undoubtedly vary from site to site, depending on drip water flow rate, residence time, drip water-cave air P differential, and availability of low P void spaces in the vadose zone above the cave. High-resolution cave environmental measurements were used to model calcite deposition on one stalagmite in Crag Cave, SW Ireland, and modelled growth over the study period (222 μm over 171 days) is extremely similar to the amount of actual calcite growth (240 μm) over the same time interval, strongly suggesting that equations used to estimate stalagmite growth rates are valid. Although cave air P appears to control drip water hydrochemistry in the winter, drip water dilution caused by rain events may have played a larger role during the summer, as evidenced by a series of sudden drops in Ca 2+ concentrations (dilution) followed by much more gradual increases in drip water Ca 2+ concentrations (slow addition of diffuse water). This research demonstrates that PCP on stalactites, cave ceilings, and void spaces within the karst above the cave partially controls drip water chemistry, and that thorough characterisation of this process at individual caves is necessary to most accurately interpret climate records from those sites.

  20. The Analysis of Ratings Using Generalizability Theory for Student Outcome Assessment. AIR 1988 Annual Forum Paper.

    ERIC Educational Resources Information Center

    Erwin, T. Dary

    Rating scales are a typical method for evaluating a student's performance in outcomes assessment. The analysis of the quality of information from rating scales poses special measurement problems when researchers work with faculty in their development. Generalizability measurement theory offers a set of techniques for estimating errors or…

  1. Identifying Peer Institutions for Graduation Rate Comparisons. AIR 2000 Annual Forum Paper.

    ERIC Educational Resources Information Center

    Walsh, Timothy A.

    This study used publicly available information to identify institutional controllable variables that influence graduation rate and to group colleges using these factors. The dependent variable for the correlation analysis was the six-year graduation rate of the fall 1993 freshman cohort (as reported by US News and World Report) at more than 1,400…

  2. Effects of Recruiting Midwives into a Family Physician Program on Women's Awareness and Preference for Mode of Delivery and Caesarean Section Rates in Rural Areas of Kurdistan

    PubMed Central

    Hajizadeh, Shayesteh; Tehrani, Fahimeh Ramezani; Simbar, Masoumeh; Farzadfar, Farshad

    2016-01-01

    Background The accepted rate rate of caesarean section is 15%. It is expected that an increase in the density of midwives in the family physician program lead to a decrease in this indicator. This study aimed to compare the rates of caesarean section and women's awareness and preference for mode of delivery before and after the implementation of the family physician program in health centres with and without an increase in midwives density. Methods In this cross-sectional study, using multistage cluster sampling method a total of 668 mothers with two-month-old children were selected from among all mothers with two-month-old children who were living in rural areas of Kurdistan province. Using the difference-in-differences model and Matchit statistical model, the factors associated with caesarean section rates and women's awareness and preference for mode of delivery were compared in centres with and without an increase in midwives density after the implementation of the family physician program. To compare the changes before and after the program, we used the data collected from the same number of women in 2005 as the baseline. Results After adjusting for baseline data collected in 2005, the resutls showed no significant change in caesarean section rates and women's awareness and preference for mode of delivery in the centres with and without an increase in midwives density after the implementation of the family physician program. The Matchit model showed a significant mean increase 14%(0.03–0.25) in women’s awareness of the benefits of natural childbirth between 2005 and 2013 in health centres where the density of midwives increased compared with health centres where it did not. The difference-in-differences model showed that the odds ratio of women’s preference for caesarean section decreased by 41% among participants who were aware of the benefits of natural childbirth, (OR = 0.59, 95% CI: (0.22–0.85); P>0.001). Conclusions The results of this study

  3. Simulating and explaining passive air sampling rates for semi-volatile compounds on polyurethane foam passive samplers

    PubMed Central

    Petrich, Nicholas T.; Spak, Scott N.; Carmichael, Gregory R.; Hu, Dingfei; Martinez, Andres; Hornbuckle, Keri C.

    2013-01-01

    Passive air samplers (PAS) including polyurethane foam (PUF) are widely deployed as an inexpensive and practical way to sample semi-volatile pollutants. However, concentration estimates from PAS rely on constant empirical mass transfer rates, which add unquantified uncertainties to concentrations. Here we present a method for modeling hourly sampling rates for semi-volatile compounds from hourly meteorology using first-principle chemistry, physics, and fluid dynamics, calibrated from depuration experiments. This approach quantifies and explains observed effects of meteorology on variability in compound-specific sampling rates and analyte concentrations; simulates nonlinear PUF uptake; and recovers synthetic hourly concentrations at a reference temperature. Sampling rates are evaluated for polychlorinated biphenyl congeners at a network of Harner model samplers in Chicago, Illinois during 2008, finding simulated average sampling rates within analytical uncertainty of those determined from loss of depuration compounds, and confirming quasi-linear uptake. Results indicate hourly, daily and interannual variability in sampling rates, sensitivity to temporal resolution in meteorology, and predictable volatility-based relationships between congeners. We quantify importance of each simulated process to sampling rates and mass transfer and assess uncertainty contributed by advection, molecular diffusion, volatilization, and flow regime within the PAS, finding PAS chamber temperature contributes the greatest variability to total process uncertainty (7.3%). PMID:23837599

  4. Dose rate estimates from irradiated light-water-reactor fuel assemblies in air

    SciTech Connect

    Lloyd, W.R.; Sheaffer, M.K.; Sutcliffe, W.G.

    1994-01-31

    It is generally considered that irradiated spent fuel is so radioactive (self-protecting) that it can only be moved and processed with specialized equipment and facilities. However, a small, possibly subnational, group acting in secret with no concern for the environment (other than the reduction of signatures) and willing to incur substantial but not lethal radiation doses, could obtain plutonium by stealing and processing irradiated spent fuel that has cooled for several years. In this paper, we estimate the dose rate at various distances and directions from typical pressurized-water reactor (PWR) and boiling-water reactor (BWR) spent-fuel assemblies as a function of cooling time. Our results show that the dose rate is reduced rapidly for the first ten years after exposure in the reactor, and that it is reduced by a factor of {approx}10 (from the one year dose rate) after 15 years. Even for fuel that has cooled for 15 years, a lethal dose (LD50) of 450 rem would be received at 1 m from the center of the fuel assembly after several minutes. However, moving from 1 to 5 m reduces the dose rate by over a factor of 10, and moving from 1 to 10 m reduces the dose rate by about a factor of 50. The dose rates 1 m from the top or bottom of the assembly are considerably less (about 10 and 22%, respectively) than 1 m from the center of the assembly, which is the direction of the maximum dose rate.

  5. 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

  6. 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.

  7. Cooling rates of living and killed chicken and quail eggs in air and in helium-oxygen gas mixture.

    PubMed

    Tazawa, H; Turner, J S; Paganelli, C V

    1988-01-01

    1. In a helium atmosphere, heat is dissipated from a surface 3.5 times faster than it is in air. Eggs in a helium-oxygen atmosphere cool only 1.4 times faster than they cool in air. This signifies that internal resistance to heat flow is a significant factor in the cooling rates of eggs. 2. Heat flow occurs inside an egg in two ways: by conduction through the tissues and in flowing blood. Killing an embryo stops the latter, but not the former. Eggs cool more slowly after they have been killed, signifying that blood flow can be an important component in an egg's internal flows of heat. 3. Blood flow should be a relatively more important component of heat flow in large eggs than in small eggs. The difference in conductance between living and killed eggs is larger in 60 g chicken eggs than it is in 10 g quail eggs. PMID:2900113

  8. 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...

  9. 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.

  10. 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).

  11. Export of Abscisic Acid, 1-Aminocyclopropane-1-Carboxylic Acid, Phosphate, and Nitrate from Roots to Shoots of Flooded Tomato Plants (Accounting for Effects of Xylem Sap Flow Rate on Concentration and Delivery).

    PubMed Central

    Else, M. A.; Hall, K. C.; Arnold, G. M.; Davies, W. J.; Jackson, M. B.

    1995-01-01

    We determined whether root stress alters the output of physiologically active messages passing from roots to shoots in the transpiration stream. Concentrations were not good measures of output. This was because changes in volume flow of xylem sap caused either by sampling procedures or by effects of root stress on rates of whole-plant transpiration modified concentrations simply by dilution. Thus, delivery rate (concentration x sap flow rate) was preferred to concentration as a measure of solute output from roots. To demonstrate these points, 1-aminocyclopropane-1-carboxylic acid (ACC), abscisic acid, phosphate, nitrate, and pH were measured in xylem sap of flooded and well-drained tomato (Lycopersicon esculentum Mill., cv Ailsa Craig) plants expressed at various rates from pressurized detopped roots. Concentrations decreased as sap flow rates were increased. However, dilution of solutes was often less than proportional to flow, especially in flooded plants. Thus, sap flowing through detopped roots at whole-plant transpiration rates was used to estimate solute delivery rates in intact plants. On this basis, delivery of ACC from roots to shoots was 3.1-fold greater in plants flooded for 24 h than in well-drained plants, and delivery of phosphate was 2.3-fold greater. Delivery rates of abscisic acid and nitrate in flooded plants were only 11 and 7%, respectively, of those in well-drained plants. PMID:12228364

  12. 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. PMID:20478555

  13. Microalgae cultivation in air-lift reactors: modeling biomass yield and growth rate as a function of mixing frequency.

    PubMed

    Barbosa, Maria J; Janssen, Marcel; Ham, Nienke; Tramper, Johannes; Wijffels, René H

    2003-04-20

    The slow development of microalgal biotechnology stems from the failure in the design of large-scale photobioreactors where light energy is efficiently utilized. Due to the light gradient inside the reactor and depending on the mixing properties, algae are subjected to certain light/dark cycles where the light period is characterized by a light gradient. These light/dark cycles will determine productivity and biomass yield on light energy. Air-lift reactors can be used for microalgae cultivation and medium-frequency light/dark cycles will be found in these systems. Light/dark cycles are associated with two basic parameters: first, the light fraction, i.e., the ratio between the light period and the cycle time and second, the frequency of the light/dark cycle. In the present work, light/dark cycles found in air-lift reactors were simulated taking into account the light gradient during the light period. The effect of medium-frequency cycle time (10-100 s) and light fraction (0.1-1) on growth rate and biomass yield on light energy of the microalgae Dunaliella tertiolecta was studied. The biomass yield and growth rates were mainly affected by the light fraction, while cycle time had little influence. Response surface methodology was used and a statistical model describing the effect of light fraction and cycle time on growth rate and biomass yield on light energy was developed. The use of the model as a reactor design criterion is discussed. PMID:12584758

  14. 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.

  15. 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.

  16. 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.

  17. 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. PMID:10894453

  18. Safety in the Chemical Laboratory: Laboratory Air Quality: Part II. Measurements of Ventilation Rates.

    ERIC Educational Resources Information Center

    Butcher, Samuel S.; And Others

    1985-01-01

    Part I of this paper (SE 538 295) described a simple model for estimating laboratory concentrations of gas phase pollutants. In this part, the measurement of ventilation rates and applications of the model are discussed. The model can provide a useful starting point in planning for safer instructional laboratories. (JN)

  19. Numerical analysis of reaction-diffusion effects on species mixing rates in turbulent premixed methane-air combustion

    SciTech Connect

    Richardson, E.S.; Grout, R.W.; Chen, J.H.; Sankaran, R.

    2010-03-15

    The scalar mixing time scale, a key quantity in many turbulent combustion models, is investigated for reactive scalars in premixed combustion. Direct numerical simulations (DNS) of three-dimensional, turbulent Bunsen flames with reduced methane-air chemistry have been analyzed in the thin reaction zones regime. Previous conclusions from single step chemistry DNS studies are confirmed regarding the role of dilatation and turbulence-chemistry interactions on the progress variable dissipation rate. Compared to the progress variable, the mixing rates of intermediate species is found to be several times greater. The variation of species mixing rates are explained with reference to the structure of one-dimensional premixed laminar flames. According to this analysis, mixing rates are governed by the strong gradients which are imposed by flamelet structures at high Damkoehler numbers. This suggests a modeling approach to estimate the mixing rate of individual species which can be applied, for example, in transported probability density function simulations. Flame-turbulence interactions which modify the flamelet based representation are analyzed. (author)

  20. Corrosion product identification and relative rates of corrosion of candidate metals in an irradiated air-steam environment

    SciTech Connect

    Reed, D.T.; Swayambunathan, V.; Tani, B.S. ); Van Konynenburg, R.A. )

    1989-11-03

    Previously reported work by others indicates that dicopper trihydroxide nitrate, Cu{sub 2}NO{sub 3}(OH){sub 3}, forms on copper and copper alloys subjected to irradiated moist air near room temperature. We have performed experiments over a range of temperature and humidity, and have found that this species is formed at temperatures up to at least 150{degree}C if low to intermediate relative humidities are present. At 150{degree}C and 100% relative humidity, only Cu{sub 2}O and CuO were observed. The relative general corrosion rates of the copper materials tested in 1-month experiments at dose rates of 0.7 and 2.0 kGy/h were Cu > 70/30 Cu--Ni > Al-bronze. High-nickel alloy 825 showed no observable corrosion. 29 refs., 4 tabs.

  1. 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.

  2. Limiting the caesarean section rate in low risk pregnancies is key to lowering the trend of increased abdominal deliveries: an observational study

    PubMed Central

    2012-01-01

    Background As the rate of Caesarean sections (CS) continues to rise in Western countries, it is important to analyze the reasons for this trend and to unravel the underlying motives to perform CS. This research aims to assess the incidence and trend of CS in a population-based birth register in order to identify patient groups with an increasing risk for CS. Methods Data from the Flemish birth register 'Study Centre for Perinatal Epidemiology' (SPE) were used for this historic control comparison. Caesarean sections (CS) from the year 2000 (N = 10540) were compared with those from the year 2008 (N = 14016). By means of the Robson classification, births by Caesarean section were ordered in 10 groups according to mother - and delivery characteristics. Results Over a period of eight years, the CS rise is most prominent in women with previous sections and in nulliparous women with a term cephalic in spontaneous labor. The proportion of inductions of labor decreases in favor of elective CS, while the ongoing inductions of labor more often end in non-elective CS. Conclusions In order to turn back the current CS trend, we should focus on low-risk primiparae. Avoiding unnecessary abdominal deliveries in this group will also have a long-term effect, in that the number of repeat CS will be reduced in the future. For the purpose of self-evaluation, peer discussion on the necessity of CS, as well as accurate registration of the main indication for CS are recommended. PMID:22230339

  3. 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

  4. 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

  5. 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.

  6. 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...

  7. 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...

  8. 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.

  9. Wind-tunnel simulation of infiltration across permeable building envelopes: Energy and air pollution exchange rates

    SciTech Connect

    Meroney, R.N.; Neff, D.E.; Birdsall, J.B.

    1995-12-31

    This study investigates the fluid-modeling techniques used to simulate wind-forced natural ventilation rates of rectangular, single-cell low-rise buildings. A 1:25 scale model of the Texas Tech University Wind Engineering Research Field Laboratory is used in a boundary-layer wind tunnel to evaluate alternative strategies for simulating infiltration into permeable buildings. A new approach is proposed which should permit evaluation of a wide range of leakage situations. In addition data is used to critique standard full-scale tracer gas test methods.

  10. 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 ...

  11. Improvement Accuracy of Assessment of Total Equivalent Dose Rate during Air Travel

    NASA Astrophysics Data System (ADS)

    Dorenskiy, Sergey; Minligareev, Vladimir

    For radiation safety on the classic flight altitudes 8-11 km is necessary to develop a methodology for calculating the total equivalent dose rate (EDR) to prevent excess exposure of passengers and crews of airliners. During development it became necessary to assess all components affecting the calculation of EDR Comprehensive analysis of the solution to this problem, based on the developed program basis, allowing to automate calculations , as well as on the assessment of the statistical data is introduced. The results have shown that: 1) Limiting accuracy of error of geomagnetic cutoff rigidity (GCR) in the period from 2005 to 2010 was 5% This error is not significant within the considered problems. 2) It is necessary to take into account seasonal variations of atmospheric parameters in the calculation of the EDR. The difference in the determination of dose rate can reach 31% Diurnal variations of atmospheric parameters are offered to consider to improve reliability of EDR estimates. 3) Introduction in the GCR calculations of additional parameters is necessary for reliability improvement and estimation accuracy of EDR on flight routs (Kp index of geomagnetic activity , etc.).

  12. 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)

  13. 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

  14. 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.

  15. 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. PMID:24951121

  16. 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.

  17. Characteristic of flotation deinking using bio and synthetic surfactant at different air flow rate

    NASA Astrophysics Data System (ADS)

    Trismawati, Wardana, I. N. G.; Hamidi, Nurkholis; Sasongko, Mega Nur

    2016-03-01

    Flotation deinking has industrially applied but several problems keep unsolved because limitations have to compete with several variables present. Flotation deinking is multi variables process, so studying flotation deinking is still interesting. In this research, the amount of variables was reduced and focused to the performance comparison between flotation deinking of old newspaper (ONP) using biodegradable fatty acid of morinda citrifolia as the raw bio surfactant (RBS) and biodegradable fatty acid of palm oil that had been converted to be commercial surfactant (CS). The flotation was done at laboratory flotation cell equipped with orifice at different diameter (orifice number 20, 40 and 60) with adjustable airflow rate. Brightness and Effective Residual Ink Concentration (ERIC) of the deinked pulp were measured. The best results were achieved on orifice number 40 with the highest brightness of 41.96 °ISO and 40.96 °ISO when using CS and RBS respectively, and lowest ERIC of 896.82 ppm and 1001.72 ppm when using CS and RBS respectively. The percentage delta of deinking power characteristic between CS and RBS was 2.36% and 11.70% for brightness and ERIC, respectively.

  18. 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.

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

    SciTech Connect

    Wayne Hill

    2004-10-01

    The project's overall objective is to develop a commercially viable sensing system to infer the flow rate and fineness of pulverized coal flows using the dynamic signature from a pipe-mounted accelerometer. The preliminary calibration data for this effort will be obtained using a Coal Flow Test Facility built and operated by our subcontractor, Airflow Sciences Corporation, in support of an EPRI program. Airflow Sciences encountered significant difficulty getting the system up and running, with the final hurdles related to the system controls. These problems were resolved in this reporting period, so that the facility is ready for testing. Shakedown testing with our instrumentation package began late in the reporting period. Preliminary analysis of the resulting data indicates that there are problems with the instrumentation and/or test rig. Even with no flow passing through the test section, a power spectrum of the data shows strong frequency ''lines''. The data should be free of such behaviors, so the instrumentation must be recording behaviors that are unrelated to the flow. This issue must be resolved before calibration data are collected. A preliminary effort to debug the problem through long-distance consultation between Foster-Miller and Airflow Sciences personnel at the end of the reporting period did not discover the source of the problem. Consequently, a Foster-Miller engineer will visit the test facility early in the next reporting period. Assuming this effort is successful, preliminary testing and analysis should be completed in the next reporting period. Because of slack in the program schedule, there should be no net effect on the program scope, cost, or schedule.

  20. Electrospun Polymer Blend Nanofibers for Tunable Drug Delivery: The Role of Transformative Phase Separation on Controlling the Release Rate.

    PubMed

    Tipduangta, Pratchaya; Belton, Peter; Fábián, László; Wang, Li Ying; Tang, Huiru; Eddleston, Mark; Qi, Sheng

    2016-01-01

    Electrospun fibrous materials have a wide range of biomedical applications, many of them involving the use of polymers as matrices for incorporation of therapeutic agents. The use of polymer blends improves the tuneability of the physicochemical and mechanical properties of the drug loaded fibers. This also benefits the development of controlled drug release formulations, for which the release rate can be modified by altering the ratio of the polymers in the blend. However, to realize these benefits, a clear understanding of the phase behavior of the processed polymer blend is essential. This study reports an in depth investigation of the impact of the electrospinning process on the phase separation of a model partially miscible polymer blend, PVP K90 and HPMCAS, in comparison to other conventional solvent evaporation based processes including film casting and spin coating. The nanoscale stretching and ultrafast solvent removal of electrospinning lead to an enhanced apparent miscibility between the polymers, with the same blends showing micronscale phase separation when processed using film casting and spin coating. Nanoscale phase separation in electrospun blend fibers was confirmed in the dry state. Rapid, layered, macroscale phase separation of the two polymers occurred during the wetting of the fibers. This led to a biphasic drug release profile from the fibers, with a burst release from PVP-rich phases and a slower, more continuous release from HPMCAS-rich phases. It was noted that the model drug, paracetamol, had more favorable partitioning into the PVP-rich phase, which is likely to be a result of greater hydrogen bonding between PVP and paracetamol. This led to higher drug contents in the PVP-rich phases than the HPMCAS-rich phases. By alternating the proportions of the PVP and HPMCAS, the drug release rate can be modulated. PMID:26655957

  1. A pilot study to determine medical laser generated air contaminant emission rates for a simulated surgical procedure.

    PubMed

    Lippert, Julia F; Lacey, Steven E; Lopez, Ramon; Franke, John; Conroy, Lorraine; Breskey, John; Esmen, Nurtan; Liu, Li

    2014-01-01

    The U.S. Occupational Safety and Health Administration (OSHA) estimates that half a million health-care workers are exposed to laser surgical smoke each year. The purpose of this study was to establish a methodology to (1) estimate emission rates of laser-generated air contaminants (LGACs) using an emission chamber, and to (2) perform a screening study to differentiate the effects of three laser operational parameters. An emission chamber was designed, fabricated, and assessed for performance to estimate the emission rates of gases and particles associated with LGACs during a simulated surgical procedure. Two medical lasers (Holmium Yttrium Aluminum Garnet [Ho:YAG] and carbon dioxide [CO2]) were set to a range of plausible medical laser operational parameters in a simulated surgery to pyrolyze porcine skin generating plume in the emission chamber. Power, pulse repetition frequency (PRF), and beam diameter were evaluated to determine the effect of each operational parameter on emission rate using a fractional factorial design. The plume was sampled for particulate matter and seven gas phase combustion byproduct contaminants (benzene, ethylbenzene, toluene, formaldehyde, hydrogen cyanide, carbon dioxide, and carbon monoxide): the gas phase emission results are presented here. Most of the measured concentrations of gas phase contaminants were below their limit of detection (LOD), but detectable measurements enabled us to determine laser operation parameter influence on CO2 emissions. Confined to the experimental conditions of this screening study, results indicated that beam diameter was statistically significantly influential and power was marginally statistically significant to emission rates of CO2 when using the Ho:YAG laser but not with the carbon dioxide laser; PRF was not influential vis-a-vis emission rates of these gas phase contaminants. PMID:24498966

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

    SciTech Connect

    Chuang, J.; Cao, S.; Xian, Y.; Harris, B.; Mumford, J.

    1992-01-01

    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 micrometers) 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.

  3. 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.

  4. 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.

  5. Influence of specimen size, tray inclination and air flow rate on the emission of gases from biomass combustion

    NASA Astrophysics Data System (ADS)

    Amorim, E. B.; Carvalho, J. A.; Soares Neto, T. G.; Anselmo, E.; Saito, V. O.; Dias, F. F.; Santos, J. C.

    2013-08-01

    Experiments of biomass combustion were performed to determine whether specimen size, tray inclination, or combustion air flow rate was the factor that most affects the emission of carbon dioxide, carbon monoxide, and methane. The chosen biomass was Eucalyptus citriodora, a very abundant species in Brazil, utilized in many industrial applications, including combustion for energy generation. Analyses by gas chromatograph and specific online instruments were used to determine the concentrations of the main emitted gases, and the following figures were found for the emission factors: 1400 ± 101 g kg-1 of CO2, 50 ± 13 g kg-1 of CO, and 3.2 ± 0.5 g kg-1 of CH4, which agree with values published in the literature for biomass from the Amazon rainforest. Statistical analysis of the experiments determined that specimen size most significantly affected the emission of gases, especially CO2 and CO.

  6. Heart Rate and Heart Rate Variability Assessment Identifies Individual Differences in Fear Response Magnitudes to Earthquake, Free Fall, and Air Puff in Mice

    PubMed Central

    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. PMID:24667366

  7. 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.

  8. Determining air pollutant emission rates based on mass balance using airborne measurement data over the Alberta oil sands operations

    NASA Astrophysics Data System (ADS)

    Gordon, M.; Li, S.-M.; Staebler, R.; Darlington, A.; Hayden, K.; O'Brien, J.; Wolde, M.

    2015-09-01

    Top-down approaches to measure total integrated emissions provide verification of bottom-up, temporally resolved, inventory-based estimations. Aircraft-based measurements of air pollutants from sources in the Canadian oil sands were made in support of the Joint Canada-Alberta Implementation Plan for Oil Sands Monitoring during a summer intensive field campaign between 13 August and 7 September 2013. The measurements contribute to knowledge needed in support of the Joint Canada-Alberta Implementation Plan for Oil Sands Monitoring. This paper describes the top-down emission rate retrieval algorithm (TERRA) to determine facility emissions of pollutants, using SO2 and CH4 as examples, based on the aircraft measurements. In this algorithm, the flight path around a facility at multiple heights is mapped to a two-dimensional vertical screen surrounding the facility. The total transport of SO2 and CH4 through this screen is calculated using aircraft wind measurements, and facility emissions are then calculated based on the divergence theorem with estimations of box-top losses, horizontal and vertical turbulent fluxes, surface deposition, and apparent losses due to air densification and chemical reaction. Example calculations for two separate flights are presented. During an upset condition of SO2 emissions on one day, these calculations are within 5 % of the industry-reported, bottom-up measurements. During a return to normal operating conditions, the SO2 emissions are within 11 % of industry-reported, bottom-up measurements. CH4 emissions calculated with the algorithm are relatively constant within the range of uncertainties. Uncertainty of the emission rates is estimated as less than 30 %, which is primarily due to the unknown SO2 and CH4 mixing ratios near the surface below the lowest flight level.

  9. Delays in hiring Air Traffic Collegiate Training Initiative (AT-CTI) graduates and the impact on their training success rate

    NASA Astrophysics Data System (ADS)

    Jorgenson, Terra A.

    arrive at the FAA Academy. In addition, the effect of the wait on the success rate of training at the FAA Academy and at the candidate's first facility was examined. Data was collected to examine the relationship between a CTI graduate's performance in the CTI program and the individual's performance during FAA training at the FAA Academy and assignment to their first facility. Through correlation analysis of the Air Traffic Basics (AT-Basic), Air Traffic Selection and Training (AT-SAT) and Performance Verification (PV) scores there was significant correlation between the AT-Basic and PV scores. As the AT-Basic score increases so does the PV scores. There needs to be future research on GPA's, PV's, AT-SAT and AT-Basics scores to determine if any of them are predictors of CTI's success in training. If the FAA can better predict if an applicant will be successful in training, it can save the FAA money in the selection, hiring and training process.

  10. Free-air CO{sub 2} enrichment effects on rate and duration of apical development of spring wheat

    SciTech Connect

    Li, Ai-Guo; Trent, A.; Wall, G.W.; Kimball, B.A.

    1997-05-01

    Rates and durations of individual phases of wheat (Triticum aestivum L.) apical development are among the most important factors that determine yield components. Because atmospheric CO{sub 2} has been increasing steadily, it is important to evaluate the effects of elevated CO{sub 2} on wheat development. This study was conducted to determine rates and durations of leaf, spikelet, and floret primordium initiation in a Free-Air Carbon Dioxide Enrichment (FACE) system. Spring wheat (cv. Yecora Roja) was planted at the University of Arizona Maricopa Agricultural Center. The two CO{sub 2} concentrations were 550 (elevated) and 370 (ambient) {mu}mol mol{sup -1} CO{sub 2}. Individual plant samples were collected every 3 to 4 d. We dissected the main stem (MS), coleoptile tiller (T0), primary tillers (T1, T2, and T3) and secondary tillers (T00, T01, T02, T10, T11, and T12) and counted primordia. Apex primordium data were fitted to a four-piece linear-spline segmented regression model with the SAS proc NLIN. No influence of elevated CO{sub 2} (550 {mu}mol mol{sup -1}) on leaf primordium initiation of MS was detected. Nevertheless, CO{sub 2} enrichment significantly increased was detected. Nevertheless, CO{sub 2} enrichment significantly increased rates of spikelet primordium initiation of MS, T1, T2, T10, and T11, and diminished the durations of spikelet development phase of MS, T1, T2, T3, T10, and T11. Within the floret phase, CO{sub 2} enrichment significantly increased rates of floret primordium initiation of MS, floret primordium initiation of MS, T0, T1, T3, and T11. The information from this study will be utilized to predict wheat apical development and grain production in the elevated atmospheric CO{sub 2} environments of the future. 40 refs., 4 figs., 5 tabs.

  11. Transdermal delivery of contraceptives.

    PubMed

    Friend, D R

    1990-01-01

    Contraceptive agents are administered to the body through a variety of routes. Research has recently been directed at examining the transdermal route for systemic delivery of contraceptive agents, including estrogens and progestins. The transdermal route has several potential advantages over the other routes of administration: (1) improved compliance, (2) once-weekly administration, (3) delivery is easily terminated, and (4) some side effects can be alleviated based on more constant delivery rates. This article reviews the permeability of skin toward contraceptive steroids and how skin permeability is evaluated. The metabolism of contraceptive steroids is also considered. Transdermal delivery systems used to deliver contraceptives are presented, followed by a detailed discussion of several delivery systems for specific contraceptive agents such as levonorgestrel and estradiol. The potential problem of skin irritation is presented as it relates to transdermal contraceptive delivery systems, all of which will be worn chronically. PMID:2272099

  12. 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.

  13. 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.

  14. Ambient particulate air pollution, heart rate variability, and blood markers of inflammation in a panel of elderly subjects.

    PubMed Central

    Pope, C Arden; Hansen, Matthew L; Long, Russell W; Nielsen, Karen R; Eatough, Norman L; Wilson, William E; Eatough, Delbert J

    2004-01-01

    Epidemiologic studies report associations between particulate air pollution and cardiopulmonary morbidity and mortality. Although the underlying pathophysiologic mechanisms remain unclear, it has been hypothesized that altered autonomic function and pulmonary/systemic inflammation may play a role. In this study we explored the effects of air pollution on autonomic function measured by changes in heart rate variability (HRV) and blood markers of inflammation in a panel of 88 elderly subjects from three communities along the Wasatch Front in Utah. Subjects participated in multiple sessions of 24-hr ambulatory electrocardiographic monitoring and blood tests. Regression analysis was used to evaluate associations between fine particulate matter [aerodynamic diameter less than or equal to 2.5 microm (PM2.5)] and HRV, C-reactive protein (CRP), blood cell counts, and whole blood viscosity. A 100- microg/m3 increase in PM2.5 was associated with approximately a 35 (SE = 8)-msec decline in standard deviation of all normal R-R intervals (SDNN, a measure of overall HRV); a 42 (SE = 11)-msec decline in square root of the mean of the squared differences between adjacent normal R-R intervals (r-MSSD, an estimate of short-term components of HRV); and a 0.81 (SE = 0.17)-mg/dL increase in CRP. The PM2.5-HRV associations were reasonably consistent and statistically robust, but the CRP association dropped to 0.19 (SE = 0.10) after excluding the most influential subject. PM2.5 was not significantly associated with white or red blood cell counts, platelets, or whole-blood viscosity. Most short-term variability in temporal deviations of HRV and CRP was not explained by PM2.5; however, the small statistically significant associations that were observed suggest that exposure to PM2.5 may be one of multiple factors that influence HRV and CRP. PMID:14998750

  15. 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

  16. 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...

  17. Modeling air pollutant emissions from Indian auto-rickshaws: Model development and implications for fleet emission rate estimates

    NASA Astrophysics Data System (ADS)

    Grieshop, Andrew P.; Boland, Daniel; Reynolds, Conor C. O.; Gouge, Brian; Apte, Joshua S.; Rogak, Steven N.; Kandlikar, Milind

    2012-04-01

    Chassis dynamometer tests were conducted on 40 Indian auto-rickshaws with 3 different fuel-engine combinations operating on the Indian Drive Cycle (IDC). Second-by-second (1 Hz) data were collected and used to develop velocity-acceleration look-up table models for fuel consumption and emissions of CO2, CO, total hydrocarbons (THC), oxides of nitrogen (NOx) and fine particulate matter (PM2.5) for each fuel-engine combination. Models were constructed based on group-average vehicle activity and emissions data in order to represent the performance of a 'typical' vehicle. The models accurately estimated full-cycle emissions for most species, though pollutants with more variable emission rates (e.g., PM2.5) were associated with larger errors. Vehicle emissions data showed large variability for single vehicles ('intra-vehicle variability') and within the test group ('inter-vehicle variability'), complicating the development of a single model to represent a vehicle population. To evaluate the impact of this variability, sensitivity analyses were conducted using vehicle activity data other than the IDC as model input. Inter-vehicle variability dominated the uncertainty in vehicle emission modeling. 'Leave-one-out' analyses indicated that the model outputs were relatively insensitive to the specific sample of vehicles and that the vehicle samples were likely a reasonable representation of the Delhi fleet. Intra-vehicle variability in emissions was also substantial, though had a relatively minor impact on model performance. The models were used to assess whether the IDC, used for emission factor development in India, accurately represents emissions from on-road driving. Modeling based on Global Positioning System (GPS) activity data from real-world auto-rickshaws suggests that, relative to on-road vehicles in Delhi, the IDC systematically under-estimates fuel use and emissions; real-word auto-rickshaws consume 15% more fuel and emit 49% more THC and 16% more PM2.5. The models

  18. Influence of air flow rate on emission of DEHP from vinyl flooring in the emission cell FLEC: Measurements and CFD simulation

    NASA Astrophysics Data System (ADS)

    Clausen, Per Axel; Liu, Zhe; Xu, Ying; Kofoed-Sørensen, Vivi; Little, John C.

    2010-07-01

    The emission of di-(2-ethylhexyl)phthalate (DEHP) from one type of vinyl flooring with ˜15% (w/w) DEHP as plasticizer was measured at 22 °C in five FLECs + one blank FLEC (Field and Laboratory Emission Cell). Initially, the flow through all FLECs was 450 ml min -1. After 689 days the flows were changed to 1000 ml min -1, 1600 ml min -1, 2300 ml min -1, and 3000 ml min -1, respectively, in four FLECs, and kept at 450 ml min -1 in one FLEC. Air samples were collected from the effluent air at regular intervals. After 1190 days the experiments were terminated and the interior surfaces of all six FLECs were rinsed with methanol to estimate the internal surface concentrations of DEHP. The DEHP air concentration and specific emission rate (SER) at steady state was estimated for the five different flow rates. The steady-state concentrations decreased slightly with increasing air flow with only the two highest flow rates resulting in significantly lower concentrations. In contrast, the SERs increased significantly. Despite large variation, the internal surface concentrations appeared to decrease slightly with increasing FLEC flow. Computational fluid dynamic (CFD) simulations suggest that the interior gas and surface concentrations were roughly uniform for the low flow case (450 ml min -1), under which, the partitioning between the FLEC internal surface and chamber air was examined. Although paired t-tests showed no difference between CFD and experimental results for DEHP air concentrations and SERs at steady-state conditions, CFD indicated that the experimental DEHP surface concentrations in the FLECs were underestimated. In conclusion, the experiments showed that the emission of DEHP from vinyl flooring is subject to "external" control and that the SER is strongly and positively dependent on the air exchange rate. However, the increased SER almost compensates for the decrease in gas-phase concentration caused by the increased air exchange.

  19. 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.

  20. 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

  1. 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.

  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. PMID:26246583

  3. Comparison of availability and plasma clearance rates of β-hydroxy-β-methylbutyrate delivery in the free acid and calcium salt forms.

    PubMed

    Fuller, John C; Sharp, Rick L; Angus, Hector F; Khoo, Paul Y; Rathmacher, John A

    2015-11-14

    β-Hydroxy-β-methylbutyrate (HMB), a leucine metabolite, has long been supplemented as a Ca salt (Ca-HMB) to increase strength and performance gains with exercise and to reduce recovery time. Recently, the free acid form of HMB (HMB-FA) has become commercially available in capsule form (gelcap). The current study was conducted to compare the bioavailability of HMB using the two commercially available capsule forms of HMB-FA and Ca-HMB. We also compared the pharmacokinetics of each form when administered mixed in water. Ten human subjects (five male and five female) were studied in a randomised crossover design. There was no significant sex by treatment interaction for any of the pharmacokinetic parameters measured. HMB-FA administered in capsules was more efficient than Ca-HMB capsule at HMB delivery with a 37 % increase in plasma clearance rate (74·8 (sem 4·0) v. 54·5 (sem 3·2) ml/min, P<0·0001) and a 76 % increase in peak plasma HMB concentration (270·2 (sem 17·8) v. 153·9 (sem 17·9) μmol/l, P<0·006), which was reached in one-third the time (P<0·009). When HMB-FA and Ca-HMB were administered in water, the differences still favoured HMB-FA, albeit to a lesser degree. Plasma HMB with HMB-FA administered in water was greater during the early phase of absorption (up to 45 min postadministration, P<0·05); this resulted in increased AUC during the first 60 min after administration, when compared with Ca-HMB mixed in water (P<0·03). In conclusion, HMB-FA in capsule form improves clearance rate and availability of HMB compared with Ca-HMB in capsule form. PMID:26373270

  4. What is the role of wind pumping on heat and mass transfer rates at the air-snow interface?

    NASA Astrophysics Data System (ADS)

    Helgason, W.; Pomeroy, J. W.

    2010-12-01

    Accurate prediction of the turbulent exchange of sensible heat and water vapour between the atmosphere and snowpack remains a challenging task under all but the most ideal conditions. Heat and mass transfer coefficients that recognize the unique properties of the snow surface are warranted. A particular area requiring improvement concerns the role of the porous nature of snow which provides a large surface area for heat and mass exchange with the atmosphere. Wind-pumping has long been considered as a viable mechanism for incorporating aerosols into snowpacks; however these processes are not considered in parameterization schemes for heat and mass transfer near the surface. This study attempts to determine the degree to which wind pumping can increase the rates of heat and mass transfer to snow, and to ascertain which structural properties of the snowpack are needed for inclusion in heat and mass transfer coefficients that reflect wind pumping processes. Based upon a review of recent geophysical and engineering literature where porous surfaces are exploited for their ability to augment heat and mass transfer rates, a technical analysis was conducted. Numerous conceptual mechanisms of wind pumping were considered: topographically-induced flow; barometric pressure changes; high frequency pressure fluctuations at the surface; and steady flow in the interfacial region. A sensitivity analysis was performed, subjecting each conceptual model to varying thermal and hydraulic conditions at the air-snow interface, as well as variable micro-structural properties of snow. It is shown that the rate of heat and mass exchange is most sensitive to the interfacial thermal conditions and factors controlling the energy balance of the uppermost snow grains. The effect upon the thermal regime of the snowpack was found to be most significant for mechanisms of wind pumping that result in shorter flow paths near the surface, rather than those caused by low frequency pressure changes. In

  5. Rate-ratio asymptotic analysis of methane-air diffusion-flame structure for predicting production of oxides of nitrogen

    SciTech Connect

    Hewson, J.C.; Williams, F.A.

    1999-05-01

    Production rates of oxides of nitrogen in laminar methane-air diffusion flames are addressed, with thermal, prompt, and nitrous oxide mechanisms taken into account, as well as consumption processes collectively termed reburn. For this purpose, it is necessary to extend the well-known four-step flame-chemistry description to six steps, with acetylene taken out of steady-state and one-step production of nitric oxide included. Emission indices are calculated as functions of the rate of scalar dissipation at the stoichiometric mixture fraction for near-atmospheric pressures and shown to be in reasonable agreement with results obtained from numerical integrations. The various mechanisms of NO{sub x} production and consumption are verified to be strongly dependent on the flame temperature and on superequilibrium concentrations of radicals, both fuel-derived and from hydrogen-oxygen chemistry; the flame-structure analysis was extended to provide sufficient accuracy in the prediction of these quantities. It was found that for flames in near-normal ambient atmospheres, the prompt mechanism usually is most important. For longer residence times, and especially for ambient pressures and temperatures above standard, the thermal mechanism was found to increase in importance, but this increase was calculated to be offset almost entirely by NO consumption through reburn reactions. Conditions that favor reburn were observed to be those where the ratio of radical concentrations to NO concentrations is small. Longer residence times and higher pressures were demonstrated to lead both to more complete heat release and to smaller superequilibrium radical concentrations whence the correspondence between thermal production and reburn. The nitrous oxide mechanism was found to be generally less important for the conditions considered here.

  6. 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

  7. 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

  8. 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.

  9. 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. PMID:16531290

  10. 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.

  11. QUALITY ASSURANCE PROCEDURES: METHOD 28A MEASUREMENT OF AIR TO FUEL RATIO AND MINIMUM BURN RATE FOR WOOD-FIRED APPLIANCES

    EPA Science Inventory

    Quality assurance procedures are contained in this comprehensive document intended to be used as an aid for wood heater manufacturers and testing laboratories in performing measurement of air-to-fuel ratio and minimum burn rate determinations according to EPA protocol, Method 28A...

  12. 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. PMID:19468951

  13. Association of Heart Rate Variability in Taxi Drivers with Marked Changes in Particulate Air Pollution in Beijing in 2008

    PubMed Central

    Wu, Shaowei; Deng, Furong; Niu, Jie; Huang, Qinsheng; Liu, Youcheng; Guo, Xinbiao

    2010-01-01

    Background Heart rate variability (HRV), a marker of cardiac autonomic function, has been associated with particulate matter (PM) air pollution, especially in older patients and those with cardiovascular diseases. However, the effect of PM exposure on cardiac autonomic function in young, healthy adults has received less attention. Objectives We evaluated the relationship between exposure to traffic-related PM with an aerodynamic diameter ≤ 2.5 μm (PM2.5) and HRV in a highly exposed panel of taxi drivers. Methods Continuous measurements of personal exposure to PM2.5 and ambulatory electrocardiogram monitoring were conducted on 11 young healthy taxi drivers for a 12-hr work shift during their work time (0900–2100 hr) before, during, and after the Beijing 2008 Olympic Games. Mixed-effects regression models were used to estimate associations between PM2.5 exposure and percent changes in 5-min HRV indices after combining data from the three time periods and controlling for potentially confounding variables. Results Personal exposures of taxi drivers to PM2.5 changed markedly across the three time periods. The standard deviation of normal-to-normal (SDNN) intervals decreased by 2.2% [95% confidence interval (CI), −3.8% to −0.6%] with an interquartile range (IQR; 69.5 μg/m3) increase in the 30-min PM2.5 moving average, whereas the low-frequency and high-frequency powers decreased by 4.2% (95% CI, −9.0% to 0.8%) and 6.2% (95% CI, −10.7% to −1.5%), respectively, in association with an IQR increase in the 2-hr PM2.5 moving average. Conclusions Marked changes in traffic-related PM2.5 exposure were associated with altered cardiac autonomic function in young healthy adults. PMID:20056565

  14. Policy Analysis Implications of a Model to Improve the Delivery of Financial Aid to Disadvantaged Students. AIR 1983 Annual Forum Paper.

    ERIC Educational Resources Information Center

    Fenske, Robert H.; Porter, John D.

    The role of institutional research in policy analysis regarding the operation of a computer model for delivery of financial aid to disadvantaged students is considered. A student financial aid model at Arizona State University is designed to develop a profile of late appliers for aid funds and also those who file inaccurate or incomplete…

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

    PubMed Central

    Du, Liuliu; Batterman, Stuart; Godwin, Christopher; Chin, Jo-Yu; Parker, Edith; Breen, Michael; Brakefield, Wilma; Robins, Thomas; Lewis, Toby

    2012-01-01

    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 measurements in several seasons averaged 0.73 ± 0.76 h−1 (median = 0.57 h−1, n = 263) in the general living area, and much higher, 1.66 ± 1.50 h−1 (median = 1.23 h−1, n = 253) in bedrooms. Living area ACRs were highest in winter and lowest in spring; bedroom ACRs were highest in summer and lowest in spring. Bedrooms received an average of 55 ± 18% of air from elsewhere in the house; the living area received only 26 ± 20% from the bedroom. Interzonal flows did not depend on season, indoor smoking or the presence of air conditioners. A two-zone IAQ model calibrated for the field study showed large differences in pollutant levels between the living area and bedroom, and the key parameters affecting IAQ were emission rates, emission source locations, air filter use, ACRs, interzonal flows, outdoor concentrations, and PM penetration factors. The single-zone models that are commonly used for residences have substantial limitations and may inadequately represent pollutant concentrations and exposures in bedrooms and potentially other environments other where people spend a substantial fraction of time. PMID:23235286

  16. 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.…

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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. PMID:17034312

  2. 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

  3. Large conversion rates of NO2 to HNO2 observed in air masses from the South China Sea: Evidence of strong production at sea surface?

    NASA Astrophysics Data System (ADS)

    Zha, Qiaozhi; Xue, Likun; Wang, Tao; Xu, Zheng; Yeung, Chungpong; Louie, Peter K. K.; Luk, Connie W. Y.

    2014-11-01

    Nitrous acid (HONO) plays important roles in tropospheric chemistry, but its source(s) are not completely understood. Here we analyze measurements of HONO, nitrogen dioxide (NO2), and related parameters at a coastal site in Hong Kong during September-December 2012. The nocturnal NO2-to-HONO conversion rates were estimated in air masses passing over land and sea surfaces. The conversion rates in the "sea cases" (3.17-3.36 × 10-2 h-1) were significantly higher than those in the "land cases" in our study (1.20-1.30 × 10-2 h-1) and in previous studies by others. These results suggest that air-sea interactions may be a significant source of atmospheric HONO and need to be considered in chemical transport models.

  4. 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

  5. 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…

  6. 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.

  7. A Simulation of the Effects of Varying Repetition Rate and Pulse Width of Nanosecond Discharges on Premixed Lean Methane-Air Combustion

    DOE PAGESBeta

    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

  8. 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. PMID:25879307

  9. 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.

  10. 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.

  11. Improvement of oxygen transfer coefficient during Penicillium canescens culture. Influence of turbine design, agitation speed, and air flow rate on xylanase production.

    PubMed

    Gaspar, A; Strodiot, L; Thonart, P

    1998-01-01

    To improve xylanase productivity from Penicillium canescens 10-10c culture, an optimization of oxygen supply is required. Because the strain is sensitive to shear forces, leading to lower xylanase productivity as to morphological alteration, vigorous mixing is not desired. The influence of turbine design, agitation speed, and air flow rate on K1a (global mass transfer coefficient, h(-1)) and enzyme production is discussed. K1a values increased with agitation speed and air flow rate, whatever the impeller, in our assay conditions. Agitation had more influence on K1a values than air flow, when a disk-mounted blade's impeller (DT) is used; an opposite result was obtained with a hub-mounted pitched blade's impeller (PBT). Xylanase production appeared as a function of specific power (W/m3), and an optimum was found in 20 and 100 L STRs fitted with DT impellers. On the other hand, the use of a hub-mounted pitched blade impeller (PBT8), instead of a disk-mounted blade impeller (DT4), reduced the lag time of hemicellulase production and increased xylanase productivity 1.3-fold. PMID:18576019

  12. Theoretical study of the effect of liquid desiccant mass flow rate on the performance of a cross flow parallel-plate liquid desiccant-air dehumidifier

    NASA Astrophysics Data System (ADS)

    Mohammad, Abdulrahman Th.; Mat, Sohif Bin; Sulaiman, M. Y.; Sopian, K.; Al-abidi, Abduljalil A.

    2013-11-01

    A computer simulation using MATLAB is investigated to predict the distribution of air stream parameters (humidity ratio and temperature) as well as desiccant parameters (temperature and concentration) inside the parallel plate absorber. The present absorber consists of fourteen parallel plates with a surface area per unit volume ratio of 80 m2/m3. Calcium chloride as a liquid desiccant flows through the top of the plates to the bottom while the air flows through the gap between the plates making it a cross flow configuration. The model results show the effect of desiccant mass flow rate on the performance of the dehumidifier (moisture removal and dehumidifier effectiveness). Performance comparisons between present cross-flow dehumidifier and another experimental cross-flow dehumidifier in the literature are carried out. The simulation is expected to help in optimizing of a cross flow dehumidifier.

  13. Measurements of VOC/SVOC emission factors from burning incenses in an environmental test chamber: influence of temperature, relative humidity, and air exchange rate.

    PubMed

    Manoukian, A; Buiron, D; Temime-Roussel, B; Wortham, H; Quivet, E

    2016-04-01

    This study investigates the influence of three environmental indoor parameters (i.e., temperature, relative humidity, and air exchange rate) on the emission of 13 volatile organic compounds (VOCs) and semi-volatile organic compounds (SVOCs) during incense burning. Experiments have been carried out using an environmental test chamber. Statistical results from a classical two-level full factorial design highlight the predominant effect of ventilation on emission factors. The higher the ventilation, the higher the emission factor. Moreover, thanks to these results, an estimation of the concentration range for the compounds under study can be calculated and allows a quick look of indoor pollution induced by incense combustion. Carcinogenic substances (i.e., benzene, benzo(a)pyrene, and formaldehyde) produced from the incense combustion would be predicted in typical living indoors conditions to reach instantaneous concentration levels close to or higher than air quality exposure threshold values. PMID:26614451

  14. 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.

  15. 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.

  16. 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

  17. 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. PMID:26642748

  18. To Mail or To Web: Comparisons of Survey Response Rates and Respondent Characteristics. AIR 2000 Annual Forum Paper.

    ERIC Educational Resources Information Center

    Underwood, Daniel; Kim, Heather; Matier, Michael

    The purpose of this study was to explore issues arising from the proliferation in use of electronic survey methods in higher education. Specifically, it examined whether response rates differed between surveys administered utilizing traditional, mailed, paper-and-pencil instruments and surveys administered utilizing electronic mail (e-mail) and…

  19. Air travel in pregnancy: the 'air-born' study.

    PubMed

    Breathnach, F; Geoghegan, T; Daly, S; Turner, M J

    2004-06-01

    An increasingly common question posed by patients antenatally is whether air travel can be considered safe in pregnancy. The aim of this study was to assess whether any agreed standards or policies exist between airlines with respect to flying in pregnancy. Sixty-eight international airlines were surveyed, of whom seventeen (25%) replied. Three of seventeen (17.5%) airlines applied no restrictions at all to pregnant passengers; the remainder applied restrictions to air travel with varying gestations (28 to 36 weeks). A full delivery kit was carried by 5/17 airlines (29%), and some form of training in the management of a delivery was provided to the cabin crew in 12/17 airlines (70%). Experience of in-flight obstetric emergencies was reported by 11/17 airlines (65%). This study highlights a lack of consensus regarding restrictions on air travel in pregnancy. The low response rate also suggests an unwillingness on the part of the airline industry to openly declare their policy on this issue. PMID:15305617

  20. 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).

  1. Gastroretentive delivery systems: hollow beads.

    PubMed

    Talukder, R; Fassihi, R

    2004-04-01

    The objective of this study was to develop a floatable multiparticulate system with potential for intragastric sustained drug delivery. Cross-linked beads were made by using calcium and low methoxylated pectin (LMP), which is an anionic polysaccharide, and calcium, LMP, and sodium alginate. Beads were dried separately in an air convection type oven at 40 degrees C for 6 hours and in a freeze dryer to evaluate the changes in bead characteristics due to process variability. Riboflavin (B-2), tetracycline (TCN), and Methotrexate (MTX) were used as model drugs for encapsulation. Ionic and nonionic excipients were added to study their effects on the release profiles of the beads. The presence of noncross linking agents in low amounts (less than 2%) did not significantly interfere with release kinetics. For an amphoteric drug like TCN, which has pH dependent solubility, three different pHs (1.5, 5.0, and 8.0) of cross-linking media were used to evaluate the effects of pH on the drug entrapment capacity of the beads. As anticipated, highest entrapment was possible when cross-linking media pH coincided with least drug solubility. Evaluation of the drying process demonstrated that the freeze-dried beads remained buoyant over 12 hours in United States Pharmacopeia (USP) hydrochloride buffer at pH 1.5, whereas the air-dried beads remained submerged throughout the release study. Confocal laser microscopy revealed the presence of air-filled hollow spaces inside the freeze dried beads, which was responsible for the flotation property of the beads. However, the release kinetics from freeze dried beads was independent of hydrodynamic conditions. Calcium-pectinate-alginate beads released their contents at much faster rates than did calcium-pectinate beads (100% in 10 hours vs. 50% in 10 hours). It appears that the nature of cross-linking, drying method, drug solubility, and production approach are all important and provide the opportunity and potential for development of a

  2. 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. PMID:22926250

  3. 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. PMID:22720960

  4. Critical influence of finite rate chemistry and unmixedness on ignition and combustion of supersonic H2-air streams

    NASA Technical Reports Server (NTRS)

    Evans, J. S.; Schexnayder, C. J., Jr.

    1979-01-01

    Good agreement has been obtained between published profiles of composition and pitot pressure and the calculated results from a computer program in which finite rate chemistry was used. Significant differences are noted between results calculated using 7 species and 8 reactions and those calculated using 12 species and 25 reactions. Differences are also found between results in which the effect of unmixedness on reaction in turbulent flow is applied or is not applied.

  5. Delivery methods for LVSD systems

    NASA Astrophysics Data System (ADS)

    Kasner, James H.; Brower, Bernard V.

    2011-06-01

    In this paper we present formats and delivery methods of Large Volume Streaming Data (LVSD) systems. LVSD systems collect TBs of data per mission with aggregate camera sizes in the 100 Mpixel to several Gpixel range at temporal rates of 2 - 60 Hz. We present options and recommendations for the different stages of LVSD data collection and delivery, to include the raw (multi-camera) data, delivery of processed (stabilized mosaic) data, and delivery of user-defined region of interest windows. Many LVSD systems use JPEG 2000 for the compression of raw and processed data. We explore the use of the JPEG 2000 Interactive Protocol (JPIP) for interactive client/server delivery to thick-clients (desktops and laptops) and MPEG-2 and H.264 to handheld thin-clients (tablets, cell phones). We also explore the use of 3D JPEG 2000 compression, defined in ISO 15444-2, for storage and delivery as well. The delivery of raw, processed, and region of interest data requires different metadata delivery techniques and metadata content. Beyond the format and delivery of data and metadata we discuss the requirements for a client/server protocol that provides data discovery and retrieval. Finally, we look into the future as LVSD systems perform automated processing to produce "information" from the original data. This information may include tracks of moving targets, changes of the background, snap shots of targets, fusion of multiple sensors, and information about "events" that have happened.

  6. Hospital admission rates for asthma and respiratory disease in the West Midlands: their relationship to air pollution levels.

    PubMed Central

    Walters, S.; Phupinyokul, M.; Ayres, J.

    1995-01-01

    BACKGROUND--A study was undertaken to determine the relationship between hospital admissions for asthma and all respiratory conditions in electoral wards in the West Midlands and ambient levels of smoke, sulphur dioxide, and nitrogen dioxide, and to establish whether the relationship is independent of social deprivation and ethnicity, and is different for young children and older individuals. METHODS--Data on hospital admissions for acute respiratory conditions were obtained by electoral ward from the West Midlands Regional Health Authority Information Department Körner inpatient data including asthma (ICD 493) and all acute respiratory disease (466, 480-486, 490-496) for the period April 1988 to March 1990. The population for each electoral ward, percentage of ward population that was from non-white ethnic groups, and Townsend deprivation score were all calculated from 1991 census information. Data on smoke and sulphur dioxide (SO2) levels were obtained for 24 wards in Birmingham, Coventry, Wolverhampton, Dudley, Stafford, and Burton-on-Trent, and on nitrogen dioxide (NO2) levels from 39 wards in the same local authority areas. All were background urban sites and most participated in the Warren Spring national quality control programme for SO2 and smoke monitoring. Indirect age-sex standardised hospitalisation rates (SHR) for all respiratory conditions and asthma were calculated using the 1991 rates for the West Midlands RHA as the standard. Multivariate regression models were used to assess the relationship between individual pollutants and the SHR. The Townsend score and percentage of the population from non-white ethnic groups were included in all models to adjust for ethnicity and socioeconomic deprivation. RESULTS--The SHR for asthma varied almost fourfold across the region, and all respiratory SHR showed more than three fold variation. Bivariate regression revealed both Townsend score and percentage of non-white individuals to be associated with SHR for

  7. Elevated NH 3 and NO 2 air concentrations and nitrogen deposition rates in the vicinity of a highway in Southern Bavaria

    NASA Astrophysics Data System (ADS)

    Kirchner, Manfred; Jakobi, Gert; Feicht, Ernst; Bernhardt, Markus; Fischer, Anton

    A transect study consisting of air concentration and deposition measurements of nitrogen compounds was performed to estimate the potential influence of car emissions on the nitrogen input to ecosystems. Therefore, two transects each consisting of 4 plots, the first in a coniferous forest and the second one in an extensively farmed grassland, were installed perpendicular to a highway south of Munich (Bavaria). Both profiles were influenced mainly by car emissions and showed only small local influences caused by agricultural activities. In the framework of a pilot study based upon denuder measurements we found a strong temporal dependency of both nitrogen dioxide (NO 2) and ammonia (NH 3) concentrations on traffic density. In the main study air concentrations of NO 2 and NH 3 were measured by passive samplers; they used as the basis for the estimation of dry deposition. These estimations have been compared with the results of analyses from simultaneously conducted canopy throughfall deposition and open air bulk measurements of nitrate (NO 3-) and ammonium (NH 4+). Additionally, within the forest transect the variety of different soil vegetation species was recorded and quantified. We obtained a strong gradient of gas concentrations along both profiles. Whereas the bulk deposition remained quite constant along the non-forested transect, the nitrogen throughfall deposition rate diminished substantially with the distance from the highway. The deposition rate at the forest edge was twice of that inside. The nitrogen load estimated for the examined forest in the vicinity of the highway was comparable to other forest ecosystems situated near diffuse emission sources from agriculture. It could be shown that changes in soil composition and soil vegetation along the forest transect are caused by decreasing nitrogen deposition with distance from the highway. The application of road salt in winter leads to further impacts.

  8. 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

  9. 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

  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. 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. PMID:26495830

  12. Modeling the MJO rain rates using parameterized large scale dynamics: vertical structure, radiation, and horizontal advection of dry air

    NASA Astrophysics Data System (ADS)

    Wang, S.; Sobel, A. H.; Nie, J.

    2015-12-01

    Two Madden Julian Oscillation (MJO) events were observed during October and November 2011 in the equatorial Indian Ocean during the DYNAMO field campaign. Precipitation rates and large-scale vertical motion profiles derived from the DYNAMO northern sounding array are simulated in a small-domain cloud-resolving model using parameterized large-scale dynamics. Three parameterizations of large-scale dynamics --- the conventional weak temperature gradient (WTG) approximation, vertical mode based spectral WTG (SWTG), and damped gravity wave coupling (DGW) --- are employed. The target temperature profiles and radiative heating rates are taken from a control simulation in which the large-scale vertical motion is imposed (rather than directly from observations), and the model itself is significantly modified from that used in previous work. These methodological changes lead to significant improvement in the results.Simulations using all three methods, with imposed time -dependent radiation and horizontal moisture advection, capture the time variations in precipitation associated with the two MJO events well. The three methods produce significant differences in the large-scale vertical motion profile, however. WTG produces the most top-heavy and noisy profiles, while DGW's is smoother with a peak in midlevels. SWTG produces a smooth profile, somewhere between WTG and DGW, and in better agreement with observations than either of the others. Numerical experiments without horizontal advection of moisture suggest that that process significantly reduces the precipitation and suppresses the top-heaviness of large-scale vertical motion during the MJO active phases, while experiments in which the effect of cloud on radiation are disabled indicate that cloud-radiative interaction significantly amplifies the MJO. Experiments in which interactive radiation is used produce poorer agreement with observation than those with imposed time-varying radiative heating. Our results highlight the

  13. Polymer Particulates in Drug Delivery.

    PubMed

    Kaur, Harmeet; Kumar, Virender; Kumar, Krishan; Rathor, Sandeep; Kumari, Parveen; Singh, Jasbir

    2016-01-01

    Development of effective drug delivery systems is important for medicine and healthcare. Polymer particulates (micro- and nanoparticles) have opened new opportunities in the field of drug delivery by overcoming various limitations of conventional delivery methods. The properties of polymeric particles can be readily tuned by precisely engineering the constituent blocks of polymers for improving drug loading, release rate, pharmacokinetics, targeting, etc. The end-groups of various polymers can be readily modified with ligands making them suitable for recognizing by cell-specific receptors, providing cellular specificity, and superior intracellular delivery. This review will mainly cover delivery of many potential drugs and biomolecules by means of polymeric microparticles, nanoparticles and copolymer micelles or assemblies. An overview about formulation methods of polymer particulates has also been addressed. Attempt has been made to cover all the potential polymers that are well known in pharmaceutical history. PMID:26898740

  14. 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. PMID:21864595

  15. 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). PMID:10616780

  16. 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

  17. Calculation of the Effects of Structure Design on Neutron, Primary Gamma-Ray and Secondary Gamma-Ray Dose Rates in Air.

    1997-06-09

    Version 01 SKYSHINE was designed to aid in the evaluation of the effects of structure geometry on the gamma-ray dose rate at given detector positions outside of a building housing N16 gamma-ray sources. The program considers a rectangular structure enclosed by four walls and a roof. Each of the walls and the roof of the building may be subdivided into up to nine different areas, representing different materials or different thicknesses of the same materialmore » for those positions of the wall or roof. Basic sets of iron and concrete slab transmission and reflection data for 6.2 MeV gamma rays are part of the SKYSHINE block data. These data, as well as parametric air transport data for line-beam sources at a number of energies between 0.6 MeV and 6.2 MeV and ranges to 3750 ft, are used to estimate the various components of the gamma-ray dose rate at positions outside of the building. The gamma-ray source is assumed to be a 6.2-MeV point-isotropic source. SKYSHINE-III provides an increase in versatility over the original SKYSHINE code in that it addresses both neutron and gamma-ray point sources. In addition, the emitted radiation may be characterized by an energy emission spectrum defined by the user. A new SKYSHINE data base is also included. SKYIII-PC is a PC version of SKYSHINE-III. Only minor modifications were made in converting for PC use. The June 1997 replacement of the PC version corrects the previously existing index problem leading to erroneous results for the "wall-scattered/air-scattered" contribution if a roof is modeled. Associated with these changes is the precaution that the detector height should always be lower than the base of the roof. Erroneous results for the roof portion of the "wall-scattered/air- attenuated" contribution will occur if a roof is modeled and the detector is not below the roof plane.« less

  18. Blind serosurvey of HIV antibodies in newborns in 92 Italian hospitals: a method for monitoring the infection rate in women at time of delivery.

    PubMed

    Ippolito, G; Costa, F; Stegagno, M; Angeloni, P; Angeloni, U; Guzzanti, E

    1991-01-01

    In Italy, drug abusers are the major risk category for HIV infection, representing 67% of all the reported cases of AIDS. This can in part explain the higher incidence of the infection observed in Italian females (17.7%) in comparison with the data reported in Europe (11.5%) or in the U.S. (8.5%). Therefore, anti-HIV screening in newborns reflects the serologic pattern of the respective mothers and can provide a useful tool in evaluating the incidence of the infection in a relatively unselected population. Furthermore, the data collected can provide a good predictive parameter for the rate at which pediatric AIDS will develop. Blood samples were collected on filter paper for routine screenings from 39,102 consecutive newborns in 92 hospital nurseries, from eight different Italian regions, during the period June 1988-April 1989. Blood-saturated disks were screened for anti-HIV antibodies (HIV Ab) using an ELISA; positive results were confirmed using a Western blot. Among the 39,102 blood samples tested, 51 (0.00130, 95% confidence intervals, Poisson distribution of 0.00097-0.00171) were found to be positive for HIV Ab. The distribution pattern of the positive samples among the different regions correlates to the cumulative AIDS incidence rate, with a higher prevalence in urban and industrialized areas. PMID:2007975

  19. 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

  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. 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.

  2. 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.

  3. Qualification of the GASGUARD® SAS GGT Arsine Sub-Atmospheric Gas Delivery System for Ion Implantation

    NASA Astrophysics Data System (ADS)

    Dunn, James P.; Rolland, James L.; Grim, James S.; Machado, Reinaldo M.; Hartz, Christopher L.

    2006-11-01

    A beta level evaluation of the GASGUARD® SAS GGT Arsine ion implant dopant supply developed by Air Products and Chemicals, Inc. was conducted by Atmel Corporation. The evaluation included characterization of the normalized wafer yield, mass spectra, ionization efficiency, flow rate, beam current, extraction of usable material and cylinder lifetime. This new and novel sub-atmospheric dopant gas delivery system utilizes a unique electrochemical process, which can generate, on demand, high flows of arsine at a constant 400 torr pressure while limiting net inventory of arsine to only 1 gram. This paper illustrates how Atmel Corporation evaluated and released this new arsine dopant delivery system for commercial production and verified high delivery capacity, resulting in reduced gas costs and increased cylinder life compared to the traditional adsorbent based technology.

  4. Influence of human activity patterns, particle composition, and residential air exchange rates on modeled distributions of PM2.5 exposure compared with central-site monitoring data.

    PubMed

    Baxter, Lisa K; Burke, Janet; Lunden, Melissa; Turpin, Barbara J; Rich, David Q; Thevenet-Morrison, Kelly; Hodas, Natasha; Ökaynak, Halûk

    2013-01-01

    Central-site monitors do not account for factors such as outdoor-to-indoor transport and human activity patterns that influence personal exposures to ambient fine-particulate matter (PM(2.5)). We describe and compare different ambient PM(2.5) exposure estimation approaches that incorporate human activity patterns and time-resolved location-specific particle penetration and persistence indoors. Four approaches were used to estimate exposures to ambient PM(2.5) for application to the New Jersey Triggering of Myocardial Infarction Study. These include: Tier 1, central-site PM(2.5) mass; Tier 2A, the Stochastic Human Exposure and Dose Simulation (SHEDS) model using literature-based air exchange rates (AERs); Tier 2B, the Lawrence Berkeley National Laboratory (LBNL) Aerosol Penetration and Persistence (APP) and Infiltration models; and Tier 3, the SHEDS model where AERs were estimated using the LBNL Infiltration model. Mean exposure estimates from Tier 2A, 2B, and 3 exposure modeling approaches were lower than Tier 1 central-site PM(2.5) mass. Tier 2A estimates differed by season but not across the seven monitoring areas. Tier 2B and 3 geographical patterns appeared to be driven by AERs, while seasonal patterns appeared to be due to variations in PM composition and time activity patterns. These model results demonstrate heterogeneity in exposures that are not captured by the central-site monitor. PMID:23321856

  5. The effect of embryo catheter loading technique on the live birth rate

    PubMed Central

    Omidi, Marjan; Halvaei, Iman; Mangoli, Esmat; Razi, Mohammad Hossein

    2015-01-01

    Objective Embryo loading (EL) is a major step in embryo transfer (ET) and affect on the success of in vitro fertilization (IVF). This study aimed to compare the effect of two different EL techniques on the rates of pregnancy and delivery in IVF/ET cycles. Methods 207 fresh ET and 194 Frozen-thawed ET (FET) cycles were included in this retrospective study. Two groups (A and B) were defined based on the EL technique used. In group A, the entire catheter was flushed with Ham's F-10 medium. The embryos were then drawn into the catheter using one air bracket. In group B, 70 µL of air was aspirated into the syringe and the catheter was flushed using Ham's F10 medium. The medium, air, embryos, air, and finally another layer of medium were then sequentially drawn into the catheter. The main outcome measures were the pregnancy and delivery rates. Results The groups did not differ with respect to the etiology of infertility, the source of spermatozoa, the quality of the embryos, the type of EL catheter, and the ease of transfer. The pregnancy rate was similar between two groups. In fresh ET cycles, a higher delivery rate was observed in group B than it group A (78.1% vs. 60%, p=0.1). In FET cycles, the rate of delivery was significantly higher in group B than in group A to a nonsignificant extent (88.9% vs. 58.8%, p=0.06). Conclusion EL techniques did not have a significant impact on the delivery rate in either fresh or FET cycles. PMID:26815646

  6. 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

  7. Relationship between Arterial Inflow Rate and Venous Filling Index of the Lower Extremities Assessed by Air Plethysmography in Subjects with or without Axial Reflux in the Great Saphenous Vein

    PubMed Central

    2014-01-01

    Objective: To evaluate the relationship between arterial inflow rate (AIR) and venous filling index (VFI) in limbs with or without varicose veins, assessed by air plethysmography (APG). Materials and Methods: A total of 142 patients (142 limbs) visiting our clinic with leg complaints, but without arterial and venous disease, were defined as the normal group (NG), and 65 patients (65 limbs) with leg varices were defined as the varicose vein group (VG). Both groups underwent duplex ultrasonography and APG to identify venous reflux and measure hemodynamic parameters, respectively. Examinations were performed at the first visit in the NG and before and one month after treatment in the VG. Results: A strong correlation between resting AIR and VFI was found in the NG (r = 0.72) and postoperative VG (r = 0.71). Twenty-two and three limbs in the NG and postoperative VG, respectively, had a VFI over 2.0 mL/s because of the high AIR. In the VG, AIR tended to decrease after treatment (P >0.01). Conclusions: High leg AIR lead to high VFI measured by APG. AIR and VFI should be measured at the same session to assess venous hemodynamic changes after varicose vein treatment when residual venous reflux cannot be diagnosed with duplex ultrasonography. PMID:25298834

  8. Information Delivery Options over Three Decades.

    ERIC Educational Resources Information Center

    Kennedy, H. Edward

    1986-01-01

    The rate of new technology-driven innovations for information delivery has accelerated over the past three decades. New information delivery formats in the 1950s and 1960s included microforms and, in response to demands from librarians, indexing and abstracting services began to make their publications available on this medium. Electronic…

  9. 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.

  10. 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. PMID:27169731

  11. 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

  12. Osmotic micropumps for drug delivery.

    PubMed

    Herrlich, Simon; Spieth, Sven; Messner, Stephan; Zengerle, Roland

    2012-11-01

    This paper reviews miniaturized drug delivery systems applying osmotic principles for pumping. Osmotic micropumps require no electrical energy and consequently enable drug delivery systems of smallest size for a broad field of new applications. In contrast to common tablets, these pumps provide constant (zero-order) drug release rates. This facilitates systems for long term use not limited by gastrointestinal transit time and first-pass metabolism. The review focuses on parenteral routes of administration targeting drug delivery either in a site-specific or systemic way. Osmotic pumps consist of three building blocks: osmotic agent, solvent, and drug. This is used to categorize pumps into (i) single compartment systems using water from body fluids as solvent and the drug itself as the osmotic agent, (ii) two compartment systems employing a separate osmotic agent, and (iii) multi-compartment architectures employing solvent, drug and osmotic agent separately. In parallel to the micropumps, relevant applications and therapies are discussed. PMID:22370615

  13. 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

  14. 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

  15. /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.

  16. Articulating feedstock delivery device

    DOEpatents

    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.

  17. Air Pollution

    MedlinePlus

    Air pollution is a mixture of solid particles and gases in the air. Car emissions, chemicals from factories, dust, ... a gas, is a major part of air pollution in cities. When ozone forms air pollution, it's ...

  18. 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 ...

  19. Targeted Drug Delivery in Pancreatic Cancer

    PubMed Central

    Yu, Xianjun; Zhang, Yuqing; Chen, Changyi; Yao, Qizhi; Li, Min

    2009-01-01

    Effective drug delivery in pancreatic cancer treatment remains a major challenge. Because of the high resistance to chemo and radiation therapy, the overall survival rate for pancreatic cancer is extremely low. Recent advances in drug delivery systems hold great promise for improving cancer therapy. Using liposomes, nanoparticles, and carbon nanotubes to deliver cancer drugs and other therapeutic agents such as siRNA, suicide gene, oncolytic virus, small molecule inhibitor and antibody has been a success in recent pre-clinical trials. However, how to improve the specificity and stability of the delivered drug using ligand or antibody directed delivery represent a major problem. Therefore, developing novel, specific, tumor-targeted drug delivery systems is urgently needed for this terrible disease. This review summarizes the current progress on targeted drug delivery in pancreatic cancer, and provides important information on potential therapeutic targets for pancreatic cancer treatment. PMID:19853645

  20. Management of Spontaneous Vaginal Delivery.

    PubMed

    Dresang, Lee T; Yonke, Nicole

    2015-08-01

    Most of the nearly 4 million births in the United States annually are normal spontaneous vaginal deliveries. In the first stage of labor, normal birth outcomes can be improved by encouraging the patient to walk and stay in upright positions, waiting until at least 6 cm dilation to diagnose active stage arrest, providing continuous labor support, using intermittent auscultation in low-risk deliveries, and following the Centers for Disease Control and Prevention guidelines for group B streptococcus prophylaxis. Most women with a low transverse uterine incision are candidates for a trial of labor after cesarean delivery and should be counseled accordingly. Pain management during labor includes complementary modalities and systemic opioids, epidural anesthesia, and pudendal block. Outcomes in the second stage of labor can be improved by using warm perineal compresses, allowing women more time to push before intervening, and offering labor support. Delayed pushing increases the length of the second stage of labor and does not affect the rate of spontaneous vaginal delivery. A tight nuchal cord can be clamped twice and cut before delivery of the shoulders, or the baby may be delivered using a somersault maneuver in which the cord is left nuchal and the distance from the cord to placenta minimized by pushing the head toward the maternal thigh. After delivery, skin-to-skin contact with the mother is recommended. Beyond 35 weeks' gestation, there is no benefit to bulb suctioning the nose and mouth. Postpartum maternal and neonatal outcomes can be improved through delayed cord clamping, active management to prevent postpartum hemorrhage, careful examination for external anal sphincter injuries, and use of absorbable synthetic suture for second-degree perineal laceration repair. Practices that will not improve outcomes and may result in negative outcomes include discontinuation of epidurals late in labor and routine episiotomy. PMID:26280140

  1. 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.

  2. 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. PMID:26010216

  3. Intermolt development reduces oxygen delivery capacity and jumping performance in the American locust (Schistocerca americana).

    PubMed

    Kirkton, Scott D; Hennessey, Lauren E; Duffy, Bridget; Bennett, Meghan M; Lee, Wah-Keat; Greenlee, Kendra J

    2012-02-01

    Among animals, insects have the highest mass-specific metabolic rates; yet, during intermolt development the tracheal respiratory system cannot meet the increased oxygen demand of older stage insects. Using locomotory performance indices, whole body respirometry, and X-ray imaging to visualize the respiratory system, we tested the hypothesis that due to the rigid exoskeleton, an increase in body mass during the intermolt period compresses the air-filled tracheal system, thereby, reducing oxygen delivery capacity in late stage insects. Specifically, we measured air sac ventilation frequency, size, and compressibility in both the abdomen and femur of early, middle, and late stage sixth instar Schistocerca americana grasshoppers. Our results show that late stage grasshoppers have a reduced air sac ventilation frequency in the femur and decreased convective capacities in the abdomen and femur. We also used X-ray images of the abdomen and femur to calculate the total proportion of tissue dedicated to respiratory structure during the intermolt period. We found that late stage grasshoppers had a lower proportion of their body dedicated to respiratory structures, especially air sacs, which convectively ventilate the tracheal system. These intermolt changes make oxygen delivery more challenging to the tissues, especially critical ones such as the jumping muscle. Indeed, late stage grasshoppers showed reduced jump frequencies compared to early stage grasshoppers, as well as decreased mass-specific CO(2) emission rates at 3 kPa PO(2). Our findings provide a mechanism to explain how body mass changes during the intermolt period reduce oxygen delivery capacity and alter an insect's life history. PMID:21965137

  4. 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.

  5. 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.

  6. Potential Air Contamination During CO{sub 2} Angiography Using a Hand-Held Syringe: Theoretical Considerations and Gas Chromatography

    SciTech Connect

    Cho, David R.; Cho, Kyung J. Hawkins, Irvin F.

    2006-08-15

    Purpose. To assess air contamination in the hand-held syringes currently used for CO{sub 2} delivery and to determine whether there is an association between their position and the rate of air contamination. Methods. Assessment of air contamination in the syringe (20 ml) included theoretical modeling, mathematical calculation, and gas chromatography (GC). The model was used with Fick's first law to calculate the diffusion of CO{sub 2} and the amount of air contamination. For GC studies, the syringes were placed in the upright, horizontal, and inverted positions and gas samples were obtained after 5, 10, 20, 30, and 60 min. All trials with each position for each sampling time were performed five times. Results. The amounts of air contamination with time calculated mathematically were 5-10% less than those of GC. With the diffusivity of air-CO{sub 2} at 0.1599 cm{sup 2}/sec (9.594 cm{sup 2}/min), air contamination was calculated to be 60% at 60 min. With GC air contamination was 13% at 5 min, 31% at 20 min, 43% at 30 min, and 68% at 60 min. There was no difference in air contamination between the different syringe positions. Conclusion. Air contamination occurs in hand-held syringes filled with CO{sub 2} when they are open to the ambient air. The amounts of air contamination over time are similar among syringes placed in the upright, horizontal, and inverted positions.

  7. Intracochlear Drug Delivery Systems

    PubMed Central

    Borenstein, Jeffrey T.

    2011-01-01

    Introduction Advances in molecular biology and in the basic understanding of the mechanisms associated with sensorineural hearing loss and other diseases of the inner ear, are paving the way towards new approaches for treatments for millions of patients. However, the cochlea is a particularly challenging target for drug therapy, and new technologies will be required to provide safe and efficacious delivery of these compounds. Emerging delivery systems based on microfluidic technologies are showing promise as a means for direct intracochlear delivery. Ultimately, these systems may serve as a means for extended delivery of regenerative compounds to restore hearing in patients suffering from a host of auditory diseases. Areas covered in this review Recent progress in the development of drug delivery systems capable of direct intracochlear delivery is reviewed, including passive systems such as osmotic pumps, active microfluidic devices, and systems combined with currently available devices such as cochlear implants. The aim of this article is to provide a concise review of intracochlear drug delivery systems currently under development, and ultimately capable of being combined with emerging therapeutic compounds for the treatment of inner ear diseases. Expert Opinion Safe and efficacious treatment of auditory diseases will require the development of microscale delivery devices, capable of extended operation and direct application to the inner ear. These advances will require miniaturization and integration of multiple functions, including drug storage, delivery, power management and sensing, ultimately enabling closed-loop control and timed-sequence delivery devices for treatment of these diseases. PMID:21615213

  8. TH-C-17A-09: Direct Visualization and Monitoring of Medical Radiation Beams in Air

    SciTech Connect

    Fahimian, B; Ceballos, A; Turkcan, S; Kapp, D; Pratx, G

    2014-06-15

    Purpose: Radiation therapy errors are rare but potentially catastrophic. Recent fatal incidents could have been avoided by utilizing real-time methods of monitoring delivery of radiation during treatment. However, few existing methods are practical enough to be used routinely. The study presents the first experimental demonstration of a novel non-perturbing method of monitoring radiation therapy through the phenomena of air scintillation. Methods: Monitoring of radiation delivery was devised by leveraging the phenomena of nitrogen excitation in air by ionizing radiation. The excitation induced weak luminescence in the 300–400 nm range, a process called air scintillation. An electron-multiplication charge-coupled device camera (f/0.95 lens; 440 nm shortpass) was set-up in a clinical treatment vault and was used to capture air scintillation images of kilovoltage and megavoltage beams. Monte Carlo simulations were performed to determine the correlation of radiation dose to air scintillation. Results: Megavoltage beams from a Varian Clinac 21EX and kilovoltage beams from an orthovoltage unit (50 kVp, 30 mA) were visualized with a relatively short exposure time (10 s). Cherenkov luminescence produced in a plastic transparent phantom did not interfere with detection of air scintillation. The image intensity displayed an inverse intensity falloff (r{sup 2} = 0.89) along the central axis and was proportional to dose rate (r{sup 2} = 0.9998). As beam energy increased, the divergence of the imaged beam decreased. Last, air scintillation was visualized during a simulated total skin irradiation electron treatment. Conclusion: Air scintillation can be clinically detected to monitor a radiation beam in an inexpensive and non-perturbing manner. This new method is advantageous in monitoring for gross delivery and uniquely capable of wide area in a single acquisition, such as the case for online verification of total body / skin / lymphoid irradiation treatments.

  9. 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.

  10. 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...

  11. Analytic modeling of antibody versus nanocell delivery of photosensitizer

    NASA Astrophysics Data System (ADS)

    Pogue, Brian W.; Srinivasan, Subhadra; Samkoe, Kimberley; Zheng, Lei Zak; Rai, Prakash; Mai, Zhiming; Verma, Sarika; Hasan, Tayyaba

    2010-02-01

    Delivery of therapeutic agents to solid tumors is challenging, and the issues that govern this can be distilled down into parameters which allow computational modeling. In this paper, the basic rate equations and diffusion kernel for the time and space modeling of delivery are developed, along with an analytical solution to this equation. The model is then used to compare delivery of Avastin antibody relative to delivery encapsulated in a nanocell delivery vehicle. The key factors are the plasma clearance or excretion rates, and the binding, or not, as it transports into the tumor tissue. A reduction in the plasma clearance rate inherently increases available delivery over time, and additionally the reduction in binding from antibody to nanocell allows higher penetration into the tumor at the longer circulation times.

  12. Antibiotic delivery by nanobioceramics.

    PubMed

    Kumar, Ts Sampath; Madhumathi, K

    2016-08-01

    The role of nanotechnology has evinced remarkable interest in the field of drug delivery. Bioceramics are inorganic biomaterials which are frequently used as bone substitutes. They have been explored in drug delivery as carriers for antibiotics, anti-osteoporotic drugs and anticancer drugs. Bioceramic nanoparticles are excellent alternatives to polymers due to their bioactivity, pH and temperature stability, multifunctionality, biocompatibility and tunable biodegradability. The use of bioceramics for local drug delivery in the field of orthopedics offer an efficient, safe mode of drug delivery directly to the surgical site thereby overcoming the limitations of systemic drug delivery. This review focuses on the development and applications of various nanobioceramics employed as drug delivery systems for the treatment of bone infections. PMID:27444496

  13. [CAESAREAN DELIVERY: STANDARDIZING THE PRACTICES].

    PubMed

    Thellier, Élise; Benhamou, Dan

    2016-06-01

    Caesarean delivery was performed in 20% of all deliveries in France in 2010 and this rate has remained unchanged during the last 10 years. Indications to perform this procedure are well defined, especially in case of scarred uterus, twin pregnancies, macrosomia or breech presentation. Surgical (haemorrhage, urinary or intestinal tract injury) and anaesthetic (hypotension after regional anaesthesia, difficult intubation and aspiration after general anaesthesia) complications may occur during the procedure. Complications may also be encountered in the early postoperative period (haemorrhage, infection, venous thromboembolism) but also on the long-term, such as placenta accreta or uterine rupture which may significantly impact obstetric outcomes. Enhanced recovery after surgery promotes early recovery and rapid convalescence. It simplifies nursing practice after surgery and is the first important step toward a patient- and family-centred care. PMID:27538322

  14. [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. PMID:15669645

  15. Air Abrasion

    MedlinePlus

    ... delivered directly to your desktop! more... What Is Air Abrasion? Article Chapters What Is Air Abrasion? What Happens? The Pros and Cons Will I Feel Anything? Is Air Abrasion for Everyone? print full article print this ...

  16. Drug delivery systems.

    PubMed

    Robinson, D H; Mauger, J W

    1991-10-01

    New and emerging drug delivery systems for traditional drugs and the products of biotechnology are discussed, and the role of the pharmacist in ensuring the appropriate use of these systems is outlined. Advantages of advanced drug delivery systems over traditional systems are the ability to deliver a drug more selectively to a specific site; easier, more accurate, less frequent dosing; decreased variability in systemic drug concentrations; absorption that is more consistent with the site and mechanism of action; and reductions in toxic metabolites. Four basic strategies govern the mechanisms of advanced drug delivery: physical, chemical, biological, and mechanical. Oral drug delivery systems use natural and synthetic polymers to deliver the product to a specific region in the gastrointestinal tract in a timely manner that minimizes adverse effects and increases drug efficacy. Innovations in injectable and implantable delivery systems include emulsions, particulate delivery systems, micromolecular products and macromolecular drug adducts, and enzymatic-controlled delivery. Options for noninvasive drug delivery include the transdermal, respiratory, intranasal, ophthalmic, lymphatic, rectal, intravaginal, and intrauterine routes as well as topical application. Rapid growth is projected in the drug delivery systems market worldwide in the next five years. Genetic engineering has mandated the development of new strategies to deliver biotechnologically derived protein and peptide drugs and chemoimmunoconjugates. The role of the pharmacist in the era of advanced drug delivery systems will be broad based, including administering drugs, compounding, calculating dosages based on pharmacokinetic and pharmacodynamic monitoring, counseling, and research. The advent of advanced drug delivery systems offers pharmacists a new opportunity to assume an active role in patient care. PMID:1772110

  17. 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.

  18. 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.

  19. 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. PMID:25006687

  20. Mode of delivery and subsequent fertility

    PubMed Central

    Evers, E.C.; McDermott, K.C.; Blomquist, J.L.; Handa, V.L.

    2014-01-01

    to infertility after their most recent delivery (7 versus 6%, P = 0.597), the interval between their first and second births (30.8 versus 30.6 months, P = 0.872), or multiparity (75 versus 76%, P = 0.650). Across all births, a history of Cesarean delivery was not significantly associated with infertility (odds ratio [OR], 0.90; 95% confidence interval [CI], 0.64–1.26). Women who reported infertility prior to their first delivery were significantly more likely to report infertility after each subsequent delivery (OR, 5.16; 95% CI, 3.60–7.39). LIMITATIONS, REASONS FOR CAUTION Due to the use of self-reported infertility, the fertility status of some participants may be misclassified. Also, the small sample size may result in insufficient power to detect small differences between groups. Finally, a relatively high proportion of our participants were over age 35 at the time of first delivery (26%) and highly educated (37% with graduate degrees), which may indicate that our population may not be generalizable. WIDER IMPLICATIONS OF THE FINDINGS While some prior studies have shown decreased family size among women who deliver by Cesarean, our results suggest that the rate of infertility is not different after Cesarean compared with vaginal birth. Our findings should be reassuring to women who deliver by Cesarean section. STUDY FUNDING/COMPETING INTEREST(S) This study was funded by the US National Institutes of Health (NIH, R01-HD056275). No competing interests are declared. TRIAL REGISTRATION NUMBER N/A. PMID:25164023

  1. Nitric oxide delivery system for cell culture studies.

    PubMed

    Wang, Chen; Deen, William M

    2003-01-01

    To investigate the toxicity and mutagenicity of NO, methods are needed to deliver it to cell cultures at known, constant rates. To permit continuous exposures over lengthy periods, we fabricated a simple apparatus utilizing gas-permeable polydimethylsiloxane (Silastic) tubing to supply both NO and O2 to a stirred, cylindrical vessel. Mass transfer in this system was characterized by measuring the delivery rates of NO or O2 alone, and of NO to air-saturated solutions. The concentrations of NO, O2, and NO2- (the end product of NO oxidation) were monitored continuously. The total flux of nitrogen species into the liquid (as determined from the sum of NO and NO2- accumulation) was 50%-90% greater in the presence of O2, depending on the NO partial pressure in the gas. Also, the simultaneously measured mass transfer coefficients for NO and O2 differed greatly from the corresponding unreactive values. An analysis of the data using diffusion-reaction models showed that NO oxidation in the aqueous boundary layer contributed very little to the nitrogen flux increase or to variations in the mass transfer coefficients. However, the unusually strong dependence of the delivery rates on chemical reactions could be explained by postulating that partial oxidation of NO to NO2 occurred within the membrane. The rate constant we estimated for polydimethylsiloxane, 4.4 x 10(5) M-2 s(-1) at 23 degrees C, is only about one-fifth of values reported previously for water and nonpolar solvents, but the high solubilities of NO and O2 in the polymer are sufficient to make NO2 formation significant. Although considerable NO2 is calculated to enter the liquid, its reaction with aqueous NO is rapid enough to keep this undesired compound at trace levels, except within a few microns of the tubing. Thus, cells will have little exposure to NO2 PMID:12572657

  2. N-malonyl-1,2-dihydroisoquinoline as a novel carrier for specific delivery of drugs to the brain.

    PubMed

    Abdel-Aziz, Mohamed; Abuo-Rahma, Gamal El-Din A A; Hassan, Heba A; Farag, Hassan H

    2010-01-01

    N-Malonyl-1,2-dihydroisoquinoline derivatives were synthesized and investigated as a novel carrier system for site-specific and sustained delivery of drugs to the brain. Such carriers are expected to be stable against air oxidation due to the presence of the carbonyl group close to nitrogen of the dihydroisoquinoline. Reduction of the prepared isoquinolinium quaternary derivatives with sodium dithionite afforded a novel group of N-malonyl-1,2-dihydroisoquinoline chemical delivery systems (CDS). The synthesized N-malonyl-1,2-dihydroisoquinoline chemical delivery systems were subjected to various chemical and biological investigations to evaluate their ability to cross the blood-brain barrier (BBB), and to be oxidized biologically into their corresponding quaternary derivatives. The in-vitro oxidation studies showed that the designed N-malonyl-1,2-dihydroisoquinoline chemical delivery system could be oxidized into its corresponding quaternary derivatives at an adequate rate. The in-vivo distribution studies showed that these N-malonyl-1,2-dihydroisoquinoline chemical delivery systems were able to cross the blood-brain barrier at detectable concentrations. PMID:19899103

  3. Ocular drug delivery.

    PubMed

    Gaudana, Ripal; Ananthula, Hari Krishna; Parenky, Ashwin; Mitra, Ashim K

    2010-09-01

    Ocular drug delivery has been a major challenge to pharmacologists and drug delivery scientists due to its unique anatomy and physiology. Static barriers (different layers of cornea, sclera, and retina including blood aqueous and blood-retinal barriers), dynamic barriers (choroidal and conjunctival blood flow, lymphatic clearance, and tear dilution), and efflux pumps in conjunction pose a significant challenge for delivery of a drug alone or in a dosage form, especially to the posterior segment. Identification of influx transporters on various ocular tissues and designing a transporter-targeted delivery of a parent drug has gathered momentum in recent years. Parallelly, colloidal dosage forms such as nanoparticles, nanomicelles, liposomes, and microemulsions have been widely explored to overcome various static and dynamic barriers. Novel drug delivery strategies such as bioadhesive gels and fibrin sealant-based approaches were developed to sustain drug levels at the target site. Designing noninvasive sustained drug delivery systems and exploring the feasibility of topical application to deliver drugs to the posterior segment may drastically improve drug delivery in the years to come. Current developments in the field of ophthalmic drug delivery promise a significant improvement in overcoming the challenges posed by various anterior and posterior segment diseases. PMID:20437123

  4. 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.

  5. 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…

  6. Released air during vapor and air cavitation

    NASA Astrophysics Data System (ADS)

    Jablonská, Jana; Kozubková, Milada

    2016-06-01

    Cavitation today is a very important problem that is solved by means of experimental and mathematical methods. The article deals with the generation of cavitation in convergent divergent nozzle of rectangular cross section. Measurement of pressure, flow rate, temperature, amount of dissolved air in the liquid and visualization of cavitation area using high-speed camera was performed for different flow rates. The measurement results were generalized by dimensionless analysis, which allows easy detection of cavitation in the nozzle. For numerical simulation the multiphase mathematical model of cavitation consisting of water and vapor was created. During verification the disagreement with the measurements for higher flow rates was proved, therefore the model was extended to multiphase mathematical model (water, vapor and air), due to release of dissolved air. For the mathematical modeling the multiphase turbulence RNG k-ɛ model for low Reynolds number flow with vapor and air cavitation was used. Subsequently the sizes of the cavitation area were verified. In article the inlet pressure and loss coefficient depending on the amount of air added to the mathematical model are evaluated. On the basis of the approach it may be create a methodology to estimate the amount of released air added at the inlet to the modeled area.

  7. 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 ...

  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. 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.

  10. 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.

  11. Heart Rate Variability, Ambient Particulate Matter Air Pollution, and Glucose Homeostasis: The Environmental Epidemiology of Arrhythmogenesis in the Women's Health Initiative

    PubMed Central

    Quibrera, P. Miguel; Christ, Sharon L.; Liao, Duanping; Prineas, Ronald J.; Anderson, Garnet L.; Heiss, Gerardo

    2009-01-01

    Metabolic neuropathophysiology underlying the prediabetic state may confer susceptibility to the adverse health effects of ambient particulate matter <10 μm in diameter (PM10). The authors therefore examined whether impaired glucose homeostasis modifies the effect of PM10 on heart rate variability in a stratified, random sample of 4,295 Women's Health Initiative clinical trial participants, among whom electrocardiograms and fasting blood draws were repeated at 3-year intervals from 1993 to 2004. In multilevel, mixed models weighted for sampling design and adjusted for clinical and environmental covariables, PM10 exposure was inversely associated with heart rate variability. Inverse PM10–heart rate variability associations were strongest for the root mean square of successive differences in normal-to-normal RR intervals (RMSSD). Among participants with impaired fasting glucose, there were −8.3% (95% confidence interval: −13.9, −2.4) versus −0.6% (95% confidence interval: −2.4, 1.3), −8.4% (95% confidence interval: −13.8, −2.7) versus −0.3% (95% confidence interval: −2.1, 1.6), and −4.3% (95% confidence interval: −9.4, 1.0) versus −0.8% (95% confidence interval: −2.7, 1.0) decreases in the RMSSD per 10-μg/m3 increase in PM10 at high versus low levels of insulin (P < 0.01), insulin resistance (P < 0.01), and glucose (P = 0.16), respectively. These associations were stronger among participants with diabetes and weaker among those without diabetes or impaired fasting glucose. The findings suggest that insulin and insulin resistance exacerbate the adverse effect of PM10 on cardiac autonomic control and thus risk of coronary heart disease among nondiabetic, postmenopausal women with impaired fasting glucose. PMID:19208727

  12. Heart rate variability, ambient particulate matter air pollution, and glucose homeostasis: the environmental epidemiology of arrhythmogenesis in the women's health initiative.

    PubMed

    Whitsel, Eric A; Quibrera, P Miguel; Christ, Sharon L; Liao, Duanping; Prineas, Ronald J; Anderson, Garnet L; Heiss, Gerardo

    2009-03-15

    Metabolic neuropathophysiology underlying the prediabetic state may confer susceptibility to the adverse health effects of ambient particulate matter <10 microm in diameter (PM(10)). The authors therefore examined whether impaired glucose homeostasis modifies the effect of PM(10) on heart rate variability in a stratified, random sample of 4,295 Women's Health Initiative clinical trial participants, among whom electrocardiograms and fasting blood draws were repeated at 3-year intervals from 1993 to 2004. In multilevel, mixed models weighted for sampling design and adjusted for clinical and environmental covariables, PM(10) exposure was inversely associated with heart rate variability. Inverse PM(10)-heart rate variability associations were strongest for the root mean square of successive differences in normal-to-normal RR intervals (RMSSD). Among participants with impaired fasting glucose, there were -8.3% (95% confidence interval: -13.9, -2.4) versus -0.6% (95% confidence interval: -2.4, 1.3), -8.4% (95% confidence interval: -13.8, -2.7) versus -0.3% (95% confidence interval: -2.1, 1.6), and -4.3% (95% confidence interval: -9.4, 1.0) versus -0.8% (95% confidence interval: -2.7, 1.0) decreases in the RMSSD per 10-microg/m(3) increase in PM(10) at high versus low levels of insulin (P < 0.01), insulin resistance (P < 0.01), and glucose (P = 0.16), respectively. These associations were stronger among participants with diabetes and weaker among those without diabetes or impaired fasting glucose. The findings suggest that insulin and insulin resistance exacerbate the adverse effect of PM(10) on cardiac autonomic control and thus risk of coronary heart disease among nondiabetic, postmenopausal women with impaired fasting glucose. PMID:19208727

  13. 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)

  14. 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.

  15. Influence of ozone air pollution on plant-herbivore interactions. Part 2: Effects of ozone on feeding preference, growth and consumption rates of monarch butterflies (Danaus plexippus).

    PubMed

    Bolsinger, M; Lier, M E; Hughes, P R

    1992-01-01

    Effects of ozone fumigation of Asclepias curassavica L. and A. syriaca L. on feeding preference, growth, development, and nutritional indices of monarch larvae were investigated in conjunction with changes in specific leaf metabolites. While foliar chemistry was quite variable, fumigation generally decreased sugars and proteins, and increased amino acids and phenolics in A. curassavica. Effects were similar in A. syriaca except that sugars were generally increased while amino acids were usually not affected. On A. curassavica, 3rd instar larvae preferred ozone-treated leaves while 4th instars showed no preference; conversely, on A. syriaca, 3rd instars showed no preference while 4th instars preferred control leaves. Relative growth rate and relative consumption rate of 5th instars were greater on fumigated plants of both species, but other nutritional indices were unaffected. Larvae developed more rapidly on intact fumigated plants of both species than on the respective controls. The results suggest that enhanced feeding stimulation may be the primary cause of the altered behavior and performance on ozone-fumigated plants. PMID:15091975

  16. Biodegradable microspheres for parenteral delivery.

    PubMed

    Sinha, V R; Trehan, A

    2005-01-01

    Nowadays, emphasis is being laid to development of controlled release dosage forms. Interest in this technology has increased steadily over the past few years. Although oral administration of drugs is a widely accepted route of drug delivery, bioavailability of drug often varies as a result of gastrointestinal absorption, degradation by first-pass effect, and hostile environment of gastrointestinal tract. Transdermal administration for percutaneous absorption of drug is limited by the impermeable nature of the stratum corneum. Ocular and nasal delivery is also unfavorable because of degradation by enzymes present in eye tissues and nasal mucosa. Hence, the parenteral route is the most viable approach in such cases. Of the various ways of achieving long-term parenteral drug delivery, biodegradable microspheres are one of the better means of controlling the release of drug over a long time. Because of the lipidic nature of liposomes, problems such as limited physical stability and difficulty of freeze-drying are encountered. Similarly, for emulsions, stability on long-term basis and in suspensions, rheological changes during filling, injecting, and storage poses limitation. Also, in all these systems, the release rate cannot be tailored to the needs of the patient. Parenteral controlled-release formulations based on biodegradable microspheres can overcome these problems and can control the release of drug over a predetermined time span, usually in the order of days to weeks to months. Various FDA-approved controlled-release parenteral formulations based on these biodegradable microspheres are available on the market, including Lupron Depot Nutropin Depot and Zoladex. This review covers various molecules encapsulated in biodegradable microspheres for parenteral delivery. PMID:16566705

  17. 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.

  18. External dose-rate conversion factors of radionuclides for air submersion, ground surface contamination and water immersion based on the new ICRP dosimetric setting

    PubMed Central

    Yoo, Song Jae; Jang, Han-Ki; Lee, Jai-Ki; Noh, Siwan; Cho, Gyuseong

    2013-01-01

    For the assessment of external doses due to contaminated environment, the dose-rate conversion factors (DCFs) prescribed in Federal Guidance Report 12 (FGR 12) and FGR 13 have been widely used. Recently, there were significant changes in dosimetric models and parameters, which include the use of the Reference Male and Female Phantoms and the revised tissue weighting factors, as well as the updated decay data of radionuclides. In this study, the DCFs for effective and equivalent doses were calculated for three exposure settings: skyshine, groundshine and water immersion. Doses to the Reference Phantoms were calculated by Monte Carlo simulations with the MCNPX 2.7.0 radiation transport code for 26 mono-energy photons between 0.01 and 10 MeV. The transport calculations were performed for the source volume within the cut-off distances practically contributing to the dose rates, which were determined by a simplified calculation model. For small tissues for which the reduction of variances are difficult, the equivalent dose ratios to a larger tissue (with lower statistical errors) nearby were employed to make the calculation efficient. Empirical response functions relating photon energies, and the organ equivalent doses or the effective doses were then derived by the use of cubic-spline fitting of the resulting doses for 26 energy points. The DCFs for all radionuclides considered important were evaluated by combining the photon emission data of the radionuclide and the empirical response functions. Finally, contributions of accompanied beta particles to the skin equivalent doses and the effective doses were calculated separately and added to the DCFs. For radionuclides considered in this study, the new DCFs for the three exposure settings were within ±10 % when compared with DCFs in FGR 13. PMID:23542764

  19. Gamma Radiation Dose Rate in Air due to Terrestrial Radionuclides in Southern Brazil: Synthesis by Geological Units and Lithotypes Covered by the Serra do Mar Sul Aero-Geophysical Project

    SciTech Connect

    Bastos, Rodrigo O.; Appoloni, Carlos R.

    2008-08-07

    The absorbed dose rates in air due to terrestrial radionuclides were estimated from aerial gamma spectrometric data for an area of 48,600 km{sup 2} in Southern Brazil. The source data was the Serra do Mar Sul Aero-Geophysical Project back-calibrated in a cooperative work among the Geological Survey of Brazil, the Geological Survey of Canada, and Paterson, Grant and Watson Ltd. The concentrations of eU (ppm), eTh (ppm) and K (%) were converted to dose rates in air (nGy{center_dot}h{sup -1}) by accounting for the contribution of each element's concentration. Regional variation was interpreted according to lithotypes and a synthesis was performed according to the basic geological units present in the area. Higher values of total dose were estimated for felsic igneous and metamorphic rocks, with average values varying up to 119{+-}24 nGy{center_dot}h{sup -1}, obtained by Anitapolis syenite body. Sedimentary, metasedimentary and metamafic rocks presented the lower dose levels, and some beach deposits reached the lowest average total dose, 18.5{+-}8.2 nGy{center_dot}h{sup -1}. Thorium gives the main average contribution in all geological units, the highest value being reached by the nebulitic gneisses of Atuba Complex, 71{+-}23 nGy{center_dot}h{sup -1}. Potassium presents the lowest average contribution to dose rate in 53 of the 72 units analyzed, the highest contribution being obtained by intrusive alkaline bodies (28{+-}12 nGy{center_dot}h{sup -1}). The general pattern of geographic dose distribution respects well the hypotheses on geo-physicochemical behavior of radioactive elements.

  20. 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)

  1. 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 ...

  2. Assisted Vaginal Delivery

    MedlinePlus

    ... having a repeat assisted vaginal delivery in a future pregnancy? If you have had one assisted vaginal ... a vacuum device. Vacuum Device: A metal or plastic cup that is applied to the fetus’ head ...

  3. Nanotransporters for drug delivery.

    PubMed

    Lühmann, Tessa; Meinel, Lorenz

    2016-06-01

    Soluble nanotransporters for drugs can be profiled for targeted delivery particularly to maximize the efficacy of highly potent drugs while minimizing off target effects. This article outlines on the use of biological carrier molecules with a focus on albumin, various drug linkers for site specific release of the drug payload from the nanotransporter and strategies to combine these in various ways to meet different drug delivery demands particularly the optimization of the payload per nanotransporter. PMID:26773302

  4. [Transdermal Delivery of NSAIDs].

    PubMed

    Nakajima, Takehisa; Makino, Kimiko

    2015-11-01

    Skin has been studied as administration site of drug for its systemic effects, since systemic therapeutic agents can be delivered for long time with a controlled ratio, escaping from the first pass effect by liver by the transdermal delivery, which can decrease the dosage form. The low permeability of drug molecules through stratum corneum has been the limiting factor for developing transdermal delivery system of therapeutic agents. To enhance the permeability of drug molecules, many studies have been reported. PMID:26689064

  5. Perspectives on the Interface of Drug Delivery and Tissue Engineering

    PubMed Central

    Ekenseair, Adam K.; Kasper, F. Kurtis; Mikos, Antonios G.

    2012-01-01

    Controlled drug delivery of bioactive molecules continues to be an essential component of engineering strategies for tissue defect repair. This article surveys the current challenges associated with trying to regenerate complex tissues utilizing drug delivery and gives perspectives on the development of translational tissue engineering therapies which promote spatiotemporal cell-signaling cascades to maximize the rate and quality of repair. PMID:23000743

  6. Matching and Conditioned Reinforcement Rate

    PubMed Central

    Shahan, Timothy A; Podlesnik, Christopher A; Jimenez-Gomez, Corina

    2006-01-01

    Attempts to examine the effects of variations in relative conditioned reinforcement rate on choice have been confounded by changes in rates of primary reinforcement or changes in the value of the conditioned reinforcer. To avoid these problems, this experiment used concurrent observing responses to examine sensitivity of choice to relative conditioned reinforcement rate. In the absence of observing responses, unsignaled periods of food delivery on a variable-interval 90-s schedule alternated with extinction on a center key (i.e., a mixed schedule was in effect). Two concurrently available observing responses produced 15-s access to a stimulus differentially associated with the schedule of food delivery (S+). The relative rate of S+ deliveries arranged by independent variable-interval schedules for the two observing responses varied across conditions. The relation between the ratio of observing responses and the ratio of S+ deliveries was well described by the generalized matching law, despite the absence of changes in the rate of food delivery. In addition, the value of the S+ deliveries likely remained constant across conditions because the ratio of S+ to mixed schedule food deliveries remained constant. Assuming that S+ deliveries serve as conditioned reinforcers, these findings are consistent with the functional similarity between primary and conditioned reinforcers suggested by general choice theories based on the concatenated matching law (e.g., contextual choice and hyperbolic value-added models). These findings are inconsistent with delay reduction theory, which has no terms for the effects of rate of conditioned reinforcement in the absence of changes in rate of primary reinforcement. PMID:16673824

  7. Effect of Remediation Parameters on in-Air Ambient Dose Equivalent Rates When Remediating Open Sites with Radiocesium-contaminated Soil.

    PubMed

    Malins, Alex; Kurikami, Hiroshi; Kitamura, Akihiro; Machida, Masahiko

    2016-10-01

    Calculations are reported for ambient dose equivalent rates [H˙*(10)] at 1 m height above the ground surface before and after remediating radiocesium-contaminated soil at wide and open sites. The results establish how the change in H˙*(10) upon remediation depends on the initial depth distribution of radiocesium within the ground, on the size of the remediated area, and on the mass per unit area of remediated soil. The remediation strategies considered were topsoil removal (with and without recovering with a clean soil layer), interchanging a topsoil layer with a subsoil layer, and in situ mixing of the topsoil. The results show the ratio of the radiocesium components of H˙*(10) post-remediation relative to their initial values (residual dose factors). It is possible to use the residual dose factors to gauge absolute changes in H˙*(10) upon remediation. The dependency of the residual dose factors on the number of years elapsed after fallout deposition is analyzed when remediation parameters remain fixed and radiocesium undergoes typical downward migration within the soil column. PMID:27575348

  8. Significances of the variability of airway paths and their air-flow rates to dosimetry model predictions of the absorption of gases

    SciTech Connect

    Overton, J.H.; Barnett, A.E.; Graham, R.C.

    1987-12-01

    The ozone-dosimetry model developed at EPA was developed to be used in conjunction with species lung models that summarize the structure of a lung as a lung of many equivalent paths. The paper reports the results of a preliminary study into the question of whether or not more realistic lung structures and airflow rates in individual airways need to be taken into account in order to make more-accurate predictions of ozone uptake. The results indicate that in order to obtain a better understanding of the distribution of absorbed ozone in the lower respiratory tract (LRT), realistic lung structures need to be taken into account. Whereas, estimating LRT dose using a lung model composed of equivalent paths was found to give the same results obtained as when the complex lung structure was taken into account. The information will allow for a better use of experimental uptake data for the evaluation of dosimetry model predictions as well as for improved interpreting of toxicological data.

  9. Management of Cesarean Deliveries and Cesarean Scars With Osteopathic Manipulative Treatment: A Brief Report.

    PubMed

    Martingano, Daniel

    2016-07-01

    Cesarean scars pose a unique set of risks for women who have had previous cesarean deliveries. Between 1996 and 2007, the rate of trial of labor after previous cesarean delivery increased, along with reported rates of uterine rupture and other complications. Consequently, trial of labor after previous cesarean delivery and resultant vaginal birth after cesarean delivery have decreased and cesarean delivery has increased. With nearly one-third of women having cesarean delivery, the rate of rare complications such as cesarean scar ectopic pregnancy has also increased. An integration of osteopathic manipulative treatment techniques into the management of cesarean deliveries and cesarean scars has yet to be defined. The author presents 4 cases of cesarean delivery in which osteopathic manipulative treatment was integrated with successful outcomes. PMID:27367961

  10. 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.

  11. 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.

  12. Air resources

    SciTech Connect

    1995-10-01

    This section describes the ambient (surrounding) air quality of the TVA region, discusses TVA emission contributions to ambient air quality, and identifies air quality impacts to human health and welfare. Volume 2 Technical Document 2, Environmental Consequences, describes how changes in TVA emissions could affect regional air quality, human health, environmental resources, and materials. The primary region of the affected environment is broadly defined as the state of Tennessee, as well as southern Kentucky, western Virginia, southern West Virginia, western North Carolina, and northern Georgia, Alabama, and Mississippi. This area represents the watershed of the Tennessee River and the 201 counties of the greater TVA service area. Emissions from outside the Tennessee Valley region contribute to air quality in the Valley. Also, TVA emissions are transported outside the Valley and have some impact on air quality beyond the primary study area. Although the study area experiences a number of air quality problems, overall air quality is good.

  13. FLUIDIC: Metal Air Recharged

    SciTech Connect

    Friesen, Cody

    2014-03-07

    Fluidic, with the help of ARPA-E funding, has developed and deployed the world's first proven high cycle life metal air battery. Metal air technology, often used in smaller scale devices like hearing aids, has the lowest cost per electron of any rechargeable battery storage in existence. Deploying these batteries for grid reliability is competitive with pumped hydro installations while having the advantages of a small footprint. Fluidic's battery technology allows utilities and other end users to store intermittent energy generated from solar and wind, as well as maintain reliable electrical delivery during power outages. The batteries are manufactured in the US and currently deployed to customers in emerging markets for cell tower reliability. As they continue to add customers, they've gained experience and real world data that will soon be leveraged for US grid reliability.

  14. FLUIDIC: Metal Air Recharged

    ScienceCinema

    Friesen, Cody

    2014-04-02

    Fluidic, with the help of ARPA-E funding, has developed and deployed the world's first proven high cycle life metal air battery. Metal air technology, often used in smaller scale devices like hearing aids, has the lowest cost per electron of any rechargeable battery storage in existence. Deploying these batteries for grid reliability is competitive with pumped hydro installations while having the advantages of a small footprint. Fluidic's battery technology allows utilities and other end users to store intermittent energy generated from solar and wind, as well as maintain reliable electrical delivery during power outages. The batteries are manufactured in the US and currently deployed to customers in emerging markets for cell tower reliability. As they continue to add customers, they've gained experience and real world data that will soon be leveraged for US grid reliability.

  15. Using Sea Level to Probe Linkages Between Heat Transport Convergence, Heat Storage Rate, and Air-Sea Heat Exchange in the Subtropical North Atlantic

    NASA Astrophysics Data System (ADS)

    Thompson, L.; Kelly, K. A.; Booth, J. F.

    2014-12-01

    Annual mean surface heat fluxes from the ocean to the atmosphere in midlatitudes are maximum in the Gulf Stream and that surface flux is driven by geostrophic heat transport convergence. Evidence is mounting that on interannual times scales, the surface flux of heat in the Gulf Stream region is controlled by the amount of heat that is stored in the region and that the heat storage rate is in turn controlled by geostrophic heat transport convergence. In addition, variations in meridional heat transport have been linked to the meridional overturning circulation just to the south of the Gulf Stream at the RAPID/MOCHA array at 26.5N, suggesting that changes in the meridional overturning circulation might be linked to surface heat exchange in the Gulf Stream. The twenty-year record of satellite sea level (SSH) along with high quality surface heat fluxes allow a detailed evaluation of the interaction between stored oceanic heat in this region and surface heat fluxes on interannual times scales. Using gridded sea level from AVISO as a proxy for upper ocean heat content along with surface turbulent heat flux from OAFlux, we evaluate the lagged correlations between interannual surface turbulent heat fluxes and SSH variability. Previous work has shown that where advection is small lagged correlations between SST (sea surface temperature) and surface turbulent heat flux are generally antisymmetric about zero lag with negative correlations when SST leads and positive correlations when SST lags. This indicates that surface heat fluxes force SST anomalies that at later times are damped by surface fluxes. In contrast, the lagged correlation between SSH anomalies and the turbulent flux of heat in the Gulf Stream region show a distinctly asymmetric relationship about zero-lag. The correlations are negative when SSH leads but are not significant when SSH lags indicating the dominant role in heat transport convergence in driving heat content changes, and that the heat content

  16. Maternal postpartum complications according to delivery mode in twin pregnancies

    PubMed Central

    Stach, Sonia Leme; Liao, Adolfo Wenjaw; de Lourdes Brizot, Maria; Francisco, Rossana Pulcineli Vieira; Zugaib, Marcelo

    2014-01-01

    OBJECTIVE: We aimed to examine maternal postpartum complications of twin deliveries according to mode of delivery and investigate the associated risk factors. METHODS: This was a retrospective cohort review of twin pregnancies with delivery after 26 weeks at a tertiary teaching hospital (1993-2008). The rates of maternal postpartum complications were compared among vaginal, elective cesarean and emergency cesarean deliveries. Significant predictors of complications were investigated with stepwise regression analysis and relative risks were calculated. RESULTS: A total of 90 complications were observed in 56/817 (6.9%) deliveries: 7/131 (5.3%) vaginal, 10/251 (4.0%) elective cesarean and 39/435 (9.0%) emergency cesarean deliveries. Significant predictors included high-risk pregnancy, gestational age at birth and delivery mode. The occurrence of complications was significantly increased in emergency compared to elective cesarean deliveries (RR = 2.34). CONCLUSIONS: Maternal postpartum complications in twin pregnancies are higher in emergency compared to elective cesarean deliveries and are also related to preexisting complications and earlier gestational age at delivery. PMID:25029574

  17. Air Pollution.

    ERIC Educational Resources Information Center

    Gilpin, Alan

    A summary of one of our most pressing environmental problems, air pollution, is offered in this book by the Director of Air Pollution Control for the Queensland (Australia) State Government. Discussion of the subject is not restricted to Queensland or Australian problems and policies, however, but includes analysis of air pollution the world over.…

  18. NANOMATERIALS FOR PROTEIN MEDIATED THERAPY AND DELIVERY

    PubMed Central

    Barry, John N.; Vertegel, Alexey A.

    2014-01-01

    There has been a significant amount of research done on liposomes and nanoparticles as drug carriers for protein drugs. Proteins and enzymes have been used both as targeting moieties and for their therapeutic potential. High specificity and rapid reaction rates make proteins and enzymes excellent candidates for therapeutic treatment, but some limitations exist. Many of these limitations can be addressed by a well studied nanotechnology based delivery system. Such a system can provide a medium for delivery, stabilization of the drugs, and enable site specific accumulation of drugs. Nanomedicines such as these have great potential to revolutionize the pharmaceutical industry and improve healthcare worldwide. PMID:25414730

  19. Technique for measuring air flow and carbon dioxide flux in large, open-top chambers

    SciTech Connect

    Ham, J.M.; Owensby, C.E.; Coyne, P.I.

    1993-10-01

    Open-Top Chambers (OTCs) are commonly used to evaluate the effect of CO{sub 2},O{sub 3}, and other trace gases on vegetation. This study developed and tested a new technique for measuring forced air flow and net CO{sub 2} flux from OTCs. Experiments were performed with a 4.5-m diam. OTC with a sealed floor and a specialized air delivery system. Air flow through the chamber was computed with the Bernoulli equation using measurements of the pressure differential between the air delivery ducts and the chamber interior. An independent measurement of air flow was made simultaneously to calibrate and verify the accuracy of the Bernoulli relationship. The CO{sub 2} flux density was calculated as the product of chamber air flow and the difference in CO{sub 2} concentration between the air entering and exhausting from the OTC (C{sub in}-C{sub out}). Accuracy was evaluated by releasing CO{sub 2} within the OTC at known rates. Data were collected with OTCs at ambient and elevated CO{sub 2} ({approx}700 {mu}mol{sup -1}). Results showed the Bernoulli equation, with a flow coefficient of 0.7, accurately measured air flow in the OTC within {+-}5% regardless of flow rate and air duct geometry. Experiments in ambient OTCs showed CO{sub 2} flux density ({mu}mol m{sup -2} s{sup -1}), computed from 2-min averages of air flow and C{sub in} - C{sub out,} was typically within {+-} 10% of actual flux, provided that the exit air velocity at the top of the OTC was greater than 0.6 m s{sup -1}. Obtaining the same accuracy in CO{sub 2}-enriched OTCs required a critical exit velocity near 1.2 m s{sup -1} to minimize the incursion of ambient air and prevent contamination of exit gas sample. When flux data were integrated over time to estimate daily CO{sub 2} flux ({mu}mol m{sup -2} d{sup -1}), actual and measured values agreed to within {+-}2% for both ambient and CO{sub 2}-enriched chambers, suggesting that accurate measurements of daily net C exchange are possible with this technique.

  20. Nanomedicine in pulmonary delivery

    PubMed Central

    Mansour, Heidi M; Rhee, Yun-Seok; Wu, Xiao

    2009-01-01

    The lung is an attractive target for drug delivery due to noninvasive administration via inhalation aerosols, avoidance of first-pass metabolism, direct delivery to the site of action for the treatment of respiratory diseases, and the availability of a huge surface area for local drug action and systemic absorption of drug. Colloidal carriers (ie, nanocarrier systems) in pulmonary drug delivery offer many advantages such as the potential to achieve relatively uniform distribution of drug dose among the alveoli, achievement of improved solubility of the drug from its own aqueous solubility, a sustained drug release which consequently reduces dosing frequency, improves patient compliance, decreases incidence of side effects, and the potential of drug internalization by cells. This review focuses on the current status and explores the potential of colloidal carriers (ie, nanocarrier systems) in pulmonary drug delivery with special attention to their pharmaceutical aspects. Manufacturing processes, in vitro/in vivo evaluation methods, and regulatory/toxicity issues of nanomedicines in pulmonary delivery are also discussed. PMID:20054434

  1. Risk factors for cesarean section and instrumental vaginal delivery after successful external cephalic version.

    PubMed

    de Hundt, Marcella; Vlemmix, Floortje; Bais, Joke M J; de Groot, Christianne J; Mol, Ben Willem; Kok, Marjolein

    2016-06-01

    Aim of this article is to examine if we could identify factors that predict cesarean section and instrumental vaginal delivery in women who had a successful external cephalic version. We used data from a previous randomized trial among 25 hospitals and their referring midwife practices in the Netherlands. With the data of this trial, we performed a cohort study among women attempting vaginal delivery after successful ECV. We evaluated whether maternal age, gestational age, parity, time interval between ECV and delivery, birth weight, neonatal gender, and induction of labor were predictive for a vaginal delivery on one hand or a CS or instrumental vaginal delivery on the other hand. Unadjusted and adjusted odds ratios were calculated with univariate and multivariate logistic regression analysis. Among 301 women who attempted vaginal delivery after a successful external cephalic version attempt, the cesarean section rate was 13% and the instrumental vaginal delivery rate 6%, resulting in a combined instrumental delivery rate of 19%. Nulliparity increased the risk of cesarean section (OR 2.7 (95% CI 1.2-6.1)) and instrumental delivery (OR 4.2 (95% CI 2.1-8.6)). Maternal age, gestational age at delivery, time interval between external cephalic version and delivery, birth weight and neonatal gender did not contribute to the prediction of failed spontaneous vaginal delivery. In our cohort of 301 women with a successful external cephalic version, nulliparity was the only one of seven factors that predicted the risk for cesarean section and instrumental vaginal delivery. PMID:26333291

  2. Transcutaneous antigen delivery system

    PubMed Central

    Lee, Mi-Young; Shin, Meong-Cheol; Yang, Victor C.

    2013-01-01

    Transcutaneous immunization refers to the topical application of antigens onto the epidermis. Transcutaneous immunization targeting the Langerhans cells of the skin has received much attention due to its safe, needle-free, and noninvasive antigen delivery. The skin has important immunological functions with unique roles for antigen-presenting cells such as epidermal Langerhans cells and dermal dendritic cells. In recent years, novel vaccine delivery strategies have continually been developed; however, transcutaneous immunization has not yet been fully exploited due to the penetration barrier represented by the stratum corneum, which inhibits the transport of antigens and adjuvants. Herein we review recent achievements in transcutaneous immunization, focusing on the various strategies for the enhancement of antigen delivery and vaccination efficacy. [BMB Reports 2013; 46(1): 17-24] PMID:23351379

  3. Chitosan coatings to control release and target tissues for therapeutic delivery.

    PubMed

    Jennings, Jessica Amber; Wells, Carlos Montez; McGraw, Gregory S; Velasquez Pulgarin, Diego A; Whitaker, Marsalas D; Pruitt, Reginald L; Bumgardner, Joel David

    2015-07-01

    The natural biopolymer chitosan has versatile applications in therapeutic delivery. Coating drug delivery matrices or biomaterials with chitosan offers several advantages in drug delivery, including control of drug release, slowing degradation rate and improving biocompatibility. Advanced uses of chitosan in coating form include targeting drug delivery vehicles to specific tissue as well as providing a stimulus-controlled release response. The present review summarizes the current applications of chitosan coatings in the context of different biomaterial delivery technologies, as well as future directions of chitosan coatings for drug delivery technologies under development. PMID:26228776

  4. Microfluidic parallel patterning and cellular delivery of molecules with a nanofountain probe.

    PubMed

    Kang, Wonmo; McNaughton, Rebecca L; Yavari, Fazel; Minary-Jolandan, Majid; Safi, Asmahan; Espinosa, Horacio D

    2014-02-01

    This brief report describes a novel tool for microfluidic patterning of biomolecules and delivery of molecules into cells. The microdevice is based on integration of nanofountain probe (NFP) chips with packaging that creates a closed system and enables operation in liquid. The packaged NFP can be easily coupled to a micro/nano manipulator or atomic force microscope for precise position and force control. We demonstrate here the functionality of the device for continuous direct-write parallel patterning on a surface in air and in liquid. Because of the small volume of the probes (~3 pL), we can achieve flow rates as low as 1 fL/s and have dispensed liquid drops with submicron to 10 µm diameters in a liquid environment. Furthermore, we demonstrate that this microdevice can be used for delivery of molecules into single cells by transient permeabilization of the cell membrane (i.e., electroporation). The significant advantage of NFP-based electroporation compared with bulk electroporation and other transfection techniques is that it allows for precise and targeted delivery while minimizing stress to the cell. We discuss the ongoing development of the tool toward automated operation and its potential as a multifunctional device for microarray applications and time-dependent single-cell studies. PMID:23897012

  5. Systems and Components Fuel Delivery System, Water Delivery System, ...

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

    Systems and Components - Fuel Delivery System, Water Delivery System, Derrick Crane System, and Crane System Details - Marshall Space Flight Center, F-1 Engine Static Test Stand, On Route 565 between Huntsville and Decatur, Huntsville, Madison County, AL

  6. Air velocity distributions from air-assisted five-port sprayer

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Capability to control both liquid and air flow rates based on tree structures would be one of the advantages of future 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-rate functions...

  7. 19 CFR 19.39 - Delivery for exportation.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... TREASURY CUSTOMS WAREHOUSES, CONTAINER STATIONS AND CONTROL OF MERCHANDISE THEREIN Duty-Free Stores § 19.39... not including departure to a contiguous country by air or sea. Deliveries from a duty-free store for... an exit point (see § 19.35(d)) from which conditionally duty-free merchandise is delivered...

  8. Delivery efficiency of an Elekta linac under gated operation.

    PubMed

    Cui, Guoqiang; Housley, David J; Chen, Fan; Mehta, Vivek K; Shepard, David M

    2014-01-01

    In this study, we have characterized the efficiency of an Elekta linac in the delivery of gated radiotherapy. We have explored techniques to reduce the beam-on delay and to improve the delivery efficiency, and have investigated the impact of frequent beam interruptions on the dosimetric accuracy of gated deliveries. A newly available gating interface was installed on an Elekta Synergy. Gating signals were generated using a surface mapping system in conjunction with a respiratory motion phantom. A series of gated deliveries were performed using volumetric modulated arc therapy (VMAT) treatment plans previously generated for lung cancer patients treated with stereotactic body radiotherapy. Baseline values were determined for the delivery times. The machine was then tuned in an effort to minimize beam-on delays and improve delivery efficiency. After that process was completed, the dosimetric accuracy of the gated deliveries was evaluated by comparing the measured and the planned coronal dose distributions using gamma index analyses. Comparison of the gated and the non-gated deliveries were also performed. The results demonstrated that, with the optimal machine settings, the average beam-on delay was reduced to less than 0.22 s. High dosimetric accuracy was demonstrated with gamma index passing rates no lower than 99.0% for all tests (3%/3 mm criteria). Consequently, Elekta linacs can provide a practical solution for gated VMAT treatments with high dosimetric accuracy and only a moderate increase in the overall delivery time. PMID:25207561

  9. Vaccine delivery using nanoparticles

    PubMed Central

    Gregory, Anthony E.; Titball, Richard; Williamson, Diane

    2013-01-01

    Vaccination has had a major impact on the control of infectious diseases. However, there are still many infectious diseases for which the development of an effective vaccine has been elusive. In many cases the failure to devise vaccines is a consequence of the inability of vaccine candidates to evoke appropriate immune responses. This is especially true where cellular immunity is required for protective immunity and this problem is compounded by the move toward devising sub-unit vaccines. Over the past decade nanoscale size (<1000 nm) materials such as virus-like particles, liposomes, ISCOMs, polymeric, and non-degradable nanospheres have received attention as potential delivery vehicles for vaccine antigens which can both stabilize vaccine antigens and act as adjuvants. Importantly, some of these nanoparticles (NPs) are able to enter antigen-presenting cells by different pathways, thereby modulating the immune response to the antigen. This may be critical for the induction of protective Th1-type immune responses to intracellular pathogens. Their properties also make them suitable for the delivery of antigens at mucosal surfaces and for intradermal administration. In this review we compare the utilities of different NP systems for the delivery of sub-unit vaccines and evaluate the potential of these delivery systems for the development of new vaccines against a range of pathogens. PMID:23532930

  10. Technological Delivery Systems.

    ERIC Educational Resources Information Center

    Kennedy, Don; And Others

    A section on technological delivery systems, presented as part of the second Australian National Workshop on Distance Education (Perth, 1983), contains four papers on using technological resources to provide educational services to persons in isolated locations. The first paper, by Don Kennedy, covers the use of satellite broadcasting of course…

  11. Document Delivery Update.

    ERIC Educational Resources Information Center

    Nelson, Nancy Melin

    1992-01-01

    Presents highlights of research that used industrywide surveys, focus groups, personal interviews, and industry-published data to explore the future of electronic information delivery in libraries. Topics discussed include CD-ROMs; prices; full-text products; magnetic tape leasing; engineering and technical literature; connections between online…

  12. Nanotopography applications in drug delivery.

    PubMed

    Walsh, Laura A; Allen, Jessica L; Desai, Tejal A

    2015-01-01

    Refinement of micro- and nanofabrication in the semiconductor field has led to innovations in biomedical technologies. Nanotopography, in particular, shows great potential in facilitating drug delivery. The flexibility of fabrication techniques has created a diverse array of topographies that have been developed for drug delivery applications. Nanowires and nanostraws deliver drug cytosolically for in vitro and ex vivo applications. In vivo drug delivery is limited by the barrier function of the epithelium. Nanowires on microspheres increase adhesion and residence time for oral drug delivery, while also increasing permeability of the epithelium. Low aspect ratio nanocolumns increase paracellular permeability, and in conjunction with microneedles increase transdermal drug delivery of biologics in vivo. In summary, nanotopography is a versatile tool for drug delivery. It can deliver directly to cells or be used for in vivo delivery across epithelial barriers. This editorial highlights the application of nanotopography in the field of drug delivery. PMID:26512871

  13. MEMS: Enabled Drug Delivery Systems.

    PubMed

    Cobo, Angelica; Sheybani, Roya; Meng, Ellis

    2015-05-01

    Drug delivery systems play a crucial role in the treatment and management of medical conditions. Microelectromechanical systems (MEMS) technologies have allowed the development of advanced miniaturized devices for medical and biological applications. This Review presents the use of MEMS technologies to produce drug delivery devices detailing the delivery mechanisms, device formats employed, and various biomedical applications. The integration of dosing control systems, examples of commercially available microtechnology-enabled drug delivery devices, remaining challenges, and future outlook are also discussed. PMID:25703045

  14. Can commonly-used fan-driven air cleaning technologies improve indoor air quality? A literature review

    NASA Astrophysics Data System (ADS)

    Zhang, Yinping; Mo, Jinhan; Li, Yuguo; Sundell, Jan; Wargocki, Pawel; Zhang, Jensen; Little, John C.; Corsi, Richard; Deng, Qihong; Leung, Michael H. K.; Fang, Lei; Chen, Wenhao; Li, Jinguang; Sun, Yuexia

    2011-08-01

    Air cleaning techniques have been applied worldwide with the goal of improving indoor air quality. The effectiveness of applying these techniques varies widely, and pollutant removal efficiency is usually determined in controlled laboratory environments which may not be realized in practice. Some air cleaners are largely ineffective, and some produce harmful by-products. To summarize what is known regarding the effectiveness of fan-driven air cleaning technologies, a state-of-the-art review of the scientific literature was undertaken by a multidisciplinary panel of experts from Europe, North America, and Asia with expertise in air cleaning, aerosol science, medicine, chemistry and ventilation. The effects on health were not examined. Over 26,000 articles were identified in major literature databases; 400 were selected as being relevant based on their titles and abstracts by the first two authors, who further reduced the number of articles to 160 based on the full texts. These articles were reviewed by the panel using predefined inclusion criteria during their first meeting. Additions were also made by the panel. Of these, 133 articles were finally selected for detailed review. Each article was assessed independently by two members of the panel and then judged by the entire panel during a consensus meeting. During this process 59 articles were deemed conclusive and their results were used for final reporting at their second meeting. The conclusions are that: (1) None of the reviewed technologies was able to effectively remove all indoor pollutants and many were found to generate undesirable by-products during operation. (2) Particle filtration and sorption of gaseous pollutants were among the most effective air cleaning technologies, but there is insufficient information regarding long-term performance and proper maintenance. (3) The existing data make it difficult to extract information such as Clean Air Delivery Rate (CADR), which represents a common benchmark for

  15. Electro-osmotically driven liquid delivery method and apparatus

    DOEpatents

    Rakestraw, David J.; Anex, Deon S.; Yan, Chao; Dadoo, Rajeev; Zare, Richard N.

    1999-01-01

    Method and apparatus for controlling precisely the composition and delivery of liquid at sub-.mu.L/min flow rate. One embodiment of such a delivery system is an electro-osmotically driven gradient flow delivery system that generates dynamic gradient flows with sub-.mu.L/min flow rates by merging a plurality of electro-osmotic flows. These flows are delivered by a plurality of delivery arms attached to a mixing connector, where they mix and then flow into a receiving means, preferably a column. Each inlet of the plurality of delivery arms is placed in a corresponding solution reservoir. A plurality of independent programmable high-voltage power supplies is used to apply a voltage program to each of the plurality of solution reservoirs to regulate the electro-osmotic flow in each delivery arm. The electro-osmotic flow rates in the delivery arms are changed with time according to each voltage program to deliver the required gradient profile to the column.

  16. Electro-osmotically driven liquid delivery method and apparatus

    DOEpatents

    Rakestraw, D.J.; Anex, D.S.; Yan, C.; Dadoo, R.; Zare, R.N.

    1999-08-24

    Method and apparatus are disclosed for controlling precisely the composition and delivery of liquid at sub-{micro}L/min flow rate. One embodiment of such a delivery system is an electro-osmotically driven gradient flow delivery system that generates dynamic gradient flows with sub-{micro}L/min flow rates by merging a plurality of electro-osmotic flows. These flows are delivered by a plurality of delivery arms attached to a mixing connector, where they mix and then flow into a receiving means, preferably a column. Each inlet of the plurality of delivery arms is placed in a corresponding solution reservoir. A plurality of independent programmable high-voltage power supplies is used to apply a voltage program to each of the plurality of solution reservoirs to regulate the electro-osmotic flow in each delivery arm. The electro-osmotic flow rates in the delivery arms are changed with time according to each voltage program to deliver the required gradient profile to the column. 4 figs.

  17. Air Pollution.

    ERIC Educational Resources Information Center

    Fox, Donald L.

    1989-01-01

    Materials related to air pollution are reviewed for the period January 1987, to October 1988. The topics are pollution monitoring, air pollution, and environmental chemistry. The organization consists of two major analytical divisions: (1) gaseous methods; and (2) aerosol and particulate methods. (MVL)

  18. Air Pollution.

    EPA Science Inventory

    Air quality is affected by many types of pollutants that are emitted from various sources, including stationary and mobile. These sources release both criteria and hazardous air pollutants, which cause health effects, ecological harm, and material damage. They are generally categ...

  19. PECTIN IN CONTROLLED DRUG DELIVERY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Controlled drug delivery remains a research focus for public health to enhance patient compliance, drug efficiency and to reduce the side effects of drugs. Pectin, an edible plant polysaccharide, has shown potential for the construction of drug delivery systems for site-specific drug delivery. Sev...

  20. Continuing Professional Education Delivery Systems.

    ERIC Educational Resources Information Center

    Weeks, James P.

    This investigation of delivery systems for continuing professional education provides an overview of current operational delivery systems in continuing professional education, drawing on experience as found in the literature. Learning theories and conclusions are woven into the descriptive text. Delivery systems profiled in the paper include the…

  1. Peptide and protein delivery using new drug delivery systems.

    PubMed

    Jain, Ashish; Jain, Aviral; Gulbake, Arvind; Shilpi, Satish; Hurkat, Pooja; Jain, Sanjay K

    2013-01-01

    Pharmaceutical and biotechnological research sorts protein drug delivery systems by importance based on their various therapeutic applications. The effective and potent action of the proteins/peptides makes them the drugs of choice for the treatment of numerous diseases. Major research issues in protein delivery include the stabilization of proteins in delivery devices and the design of appropriate target-specific protein carriers. Many efforts have been made for effective delivery of proteins/peptidal drugs through various routes of administrations for successful therapeutic effects. Nanoparticles made of biodegradable polymers such as poly lactic acid, polycaprolactone, poly(lactic-co-glycolic acid), the poly(fumaric-co-sebacic) anhydride chitosan, and modified chitosan, as well as solid lipids, have shown great potential in the delivery of proteins/peptidal drugs. Moreover, scientists also have used liposomes, PEGylated liposomes, niosomes, and aquasomes, among others, for peptidal drug delivery. They also have developed hydrogels and transdermal drug delivery systems for peptidal drug delivery. A receptor-mediated delivery system is another attractive strategy to overcome the limitation in drug absorption that enables the transcytosis of the protein across the epithelial barrier. Modification such as PEGnology is applied to various proteins and peptides of the desired protein and peptides also increases the circulating life, solubility and stability, pharmacokinetic properties, and antigenicity of protein. This review focuses on various approaches for effective protein/peptidal drug delivery, with special emphasis on insulin delivery. PMID:23662604

  2. Preterm delivery among people living around Portland cement plants.

    PubMed

    Yang, Chun-Yuh; Chang, Chih-Ching; Tsai, Shang-Shyue; Chuang, Hung-Yi; Ho, Chi-Kung; Wu, Trong-Neng; Sung, Fung-Chang

    2003-05-01

    The Portland cement industry is the main source of particulate air pollution in Kaohsiung city. Data in this study concern outdoor air pollution and the health of individuals living in communities in close proximity to Portland cement plants. The prevalence of delivery of preterm birth infants was significantly higher in mothers living within 0-2 km of a Portland cement plant than in mothers living within 2-4 km. After controlling for several possible confounders (including maternal age, season, marital status, maternal education, and infant sex), the adjusted odds ratio was 1.30 (95% CI=1.09-1.54) for the delivery of preterm infants for mothers living close to the Portland cement plants, chosen at the start to be from 0 to 2 km. These data provide further support for the hypothesis that air pollution can affect the outcome of pregnancy. PMID:12706757

  3. Implication of nanofibers in oral drug delivery.

    PubMed

    Kapahi, Himani; Khan, Nikhat Mansoor; Bhardwaj, Ankur; Mishra, Neeraj

    2015-01-01

    Nanofibers has gained significant prominence in recent years due to its wide applications in medicinal pharmacy, textile, tissue engineering and in various drug delivery system. In oral drug delivery system (DDS), nanofibers can be delivered as Nanofiber scaffolds, electrosponge nanofibers as oral fast delivery system, multilayered nanofiber loaded mashes, surface modified cross-linked electrospun nanofibers. Nanofibers are of 50- 1000 nm size fibres having large surface area, high porosity, small pore size, low density. Various approaches for formulation of nanofibers are molecular assembly, thermally induced phase separation, electrospining. Most commonly used by using electrospining polymer nanofibres with different range can be produced collective usage of electro spinning with pharmaceutical polymers offers novel tactics for developing drug delivery system (DDS). Different polymers used in preparation of nanofibers include biodegradable hydrophilic polymers, hydrophobic polymers and amphiphilic polymers. Electrospun nanofibers are often used to load insoluble drugs for enhancing their dissolution properties due to their high surface area per unit mass. Besides the water insoluble drugs freely water soluble sodium can also spun into the fibers. The most commonly polymers used for nanofibers are gelatin, dextran, nylon, polystyrene, polyacrylonitrile, polycarbonate, polyimides, poly vinyl alchol, polybenzimidazole. Delivery systems reviewed rely on temporal control, changes in pH along the GIT, the action of local enzymes to trigger drug release, and changes in intraluminal pressure. Dissolution of enteric polymer coatings due to a change in local pH and reduction of azo-bonds to release an active agent are both used in commercially marketed products. In vitro and in vivo studies have demonstrated that the release rates of drugs from these nanofiber formulations are enhanced compared to those from original drug substance. This review is focused on the different

  4. Air Cleaning Technologies

    PubMed Central

    2005-01-01

    zoster, whereas close contact is required for the direct transmission of infectious diseases transmitted by droplets, such as influenza (the flu) and SARS. The Technology In-room air cleaners are supplied as portable or fixed devices. Fixed devices can be attached to either a wall or ceiling and are preferred over portable units because they have a greater degree of reliability (if installed properly) for achieving adequate room air mixing and airflow patterns, which are important for optimal effectiveness. Through a method of air recirculation, an in-room air cleaner can be used to increase room ventilation rates and if used to exhaust air out of the room it can create a negative-pressure room for airborne infection isolation (AII) when the building’s HVAC system cannot do so. A negative-pressure room is one where clean air flows into the room but contaminated air does not flow out of it. Contaminated room air is pulled into the in-room air cleaner and cleaned by passing through a series of filters, which remove the airborne infectious pathogens. The cleaned air is either recirculated into the room or exhausted outside the building. By filtering contaminated room air and then recirculating the cleaned air into the room, an in-room air cleaner can improve the room’s ventilation. By exhausting the filtered air to the outside the unit can create a negative-pressure room. There are many types of in-room air cleaners. They vary widely in the airflow rates through the unit, the type of air cleaning technology used, and the technical design. Crucial to maximizing the efficiency of any in-room air cleaner is its strategic placement and set-up within a room, which should be done in consultation with ventilation engineers, infection control experts, and/or industrial hygienists. A poorly positioned air cleaner may disrupt airflow patterns within the room and through the air cleaner, thereby compromising its air cleaning efficiency. The effectiveness of an in-room air cleaner

  5. Delivery strategies for antiparasitics.

    PubMed

    Kayser, Oliver; Kiderlen, Albrecht F

    2003-02-01

    Optimisation of drug carrier systems and drug delivery strategies that take into account the peculiarities of individual infectious agents and diseases are key elements of modern drug development. In the following, different aspects of a rational design for antiparasitic drug formulation will be reviewed, covering delivery systems such as nano- and microparticles, liposomes, emulsions and microemulsions, cochleates and bioadhesive macromolecules. Functional properties for each carrier system will be discussed as well as their therapeutic efficacy for parasitic diseases, including leishmaniasis, human African trypanosomiasis, human cryptosporidiosis, malaria and schistosomiasis. Critical issues for the application of drug carrier systems will be discussed, focusing on biopharmaceutical and pathophysiological parameters such as routes of application, improvement of body distribution and targeting intracellularly persisting pathogens. PMID:12556214

  6. Compact SPS - Power delivery

    NASA Astrophysics Data System (ADS)

    Pospisil, M.; Pospisilova, L.

    1982-09-01

    The power deliverable by a compact solar Space Power Station (SPS) is a function of its outer surface shape. Methods of fitting the power delivery curve of such a system to different patterns of daily power demand are considered that involve the appropriate choice of the number of satellites, their maximal power, height to width ratio and the shift of longitude with respect to the receiving station. Changes in the daily delivery curve can be made by altering the longitudes and orientations of the satellites. Certain limitations to the choice of parameters exist, such as: the height to width ratio should be near 1.2, and the sum of longitude and orientation changes will probably not be greater than 50 deg. The optimization of the peak to average power ratio is also discussed.

  7. Terplex Gene Delivery System.

    PubMed

    Kim, Sung Wan

    2005-01-01

    Polymeric gene delivery systems have been developed to overcome problems caused by viral carriers. They are low cytotoxic, have no size limit, are convenient in handling, of low cost and reproducible. A Terplex gene delivery system consisting of plasmid DNA, low density lipoprotein and hydropholized poly-L-lysine was designed and characterized. The plasmid DNA, when formulated with stearyl PLL and LDL, forms a stable and hydrophobicity/charge-balanced Terplex system of optimal size for efficient cellular uptake. DNA is still intact after the Terplex formation. This information is expected to be utilized for the development of improved transfection vector for in vivo gene therapy. Terplex DNA complex showed significantly longer retention in the vascular space than naked DNA. This system was used in the augmentation of myocardial transfection at an infarction site with the VEGF gene. PMID:16243067

  8. Terplex gene delivery system.

    PubMed

    Kim, Sung Wan

    2005-01-01

    Polymeric gene delivery systems have been developed to overcome problems caused by viral carriers. They are low cytotoxic, have no size limit, are convenient in handling, of low cost and reproducible. A Terplex gene delivery system consisting of plasmid DNA, low density lipoprotein and hydropholized poly-L-lysine was designed and characterized. The plasmid DNA, when formulated with stearyl PLL and LDL, forms a stable and hydrophobicity/charge-balanced Terplex system of optimal size for efficient cellular uptake. DNA is still intact after the Terplex formation. This information is expected to be utilized for the development of improved transfection vector for in vivo gene therapy. Terplex DNA complex showed significantly longer retention in the vascular space than naked DNA. This system was used in the augmentation of myocardial transfection at an infarction site with the VEGF gene. PMID:16240997

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

    NASA Technical Reports Server (NTRS)

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

    1982-01-01

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

  10. Reproductive health care delivery.

    PubMed

    Lindgren, Mark C; Ross, Lawrence S

    2014-02-01

    Most patients in the United States with reproductive health disorders are not covered by their health insurance for these problems. Health insurance plans consider reproductive care as a lifestyle choice not as a disease. If coverage is provided it is, most often, directed to female factor infertility and advanced reproductive techniques, ignoring male factor reproductive disorders. This article reviews the history of reproductive health care delivery and its present state, and considers its possible future direction. PMID:24286778

  11. Mucosal delivery of vaccines.

    PubMed

    Del Giudice, G; Pizza, M; Rappuoli, R

    1999-09-01

    Oral delivery represents one of the most pursued approaches for large-scale human vaccination. Due to the different characteristics of mucosal immune response, as compared with systemic response, oral immunization requires particular methods of antigen preparation and selective strategies of adjuvanticity. In this paper, we describe the preparation and use of genetically detoxified bacterial toxins as mucosal adjuvants and envisage the possibility of their future exploitation for human oral vaccines. PMID:10525451

  12. Nanovehicular intracellular delivery systems.

    PubMed

    Prokop, Ales; Davidson, Jeffrey M

    2008-09-01

    This article provides an overview of principles and barriers relevant to intracellular drug and gene transport, accumulation and retention (collectively called as drug delivery) by means of nanovehicles (NV). The aim is to deliver a cargo to a particular intracellular site, if possible, to exert a local action. Some of the principles discussed in this article apply to noncolloidal drugs that are not permeable to the plasma membrane or to the blood-brain barrier. NV are defined as a wide range of nanosized particles leading to colloidal objects which are capable of entering cells and tissues and delivering a cargo intracelullarly. Different localization and targeting means are discussed. Limited discussion on pharmacokinetics and pharmacodynamics is also presented. NVs are contrasted to micro-delivery and current nanotechnologies which are already in commercial use. Newer developments in NV technologies are outlined and future applications are stressed. We also briefly review the existing modeling tools and approaches to quantitatively describe the behavior of targeted NV within the vascular and tumor compartments, an area of particular importance. While we list "elementary" phenomena related to different level of complexity of delivery to cancer, we also stress importance of multi-scale modeling and bottom-up systems biology approach. PMID:18200527

  13. Nanovehicular Intracellular Delivery Systems

    PubMed Central

    PROKOP, ALES; DAVIDSON, JEFFREY M.

    2013-01-01

    This article provides an overview of principles and barriers relevant to intracellular drug and gene transport, accumulation and retention (collectively called as drug delivery) by means of nanovehicles (NV). The aim is to deliver a cargo to a particular intracellular site, if possible, to exert a local action. Some of the principles discussed in this article apply to noncolloidal drugs that are not permeable to the plasma membrane or to the blood–brain barrier. NV are defined as a wide range of nanosized particles leading to colloidal objects which are capable of entering cells and tissues and delivering a cargo intracelullarly. Different localization and targeting means are discussed. Limited discussion on pharmacokinetics and pharmacodynamics is also presented. NVs are contrasted to micro-delivery and current nanotechnologies which are already in commercial use. Newer developments in NV technologies are outlined and future applications are stressed. We also briefly review the existing modeling tools and approaches to quantitatively describe the behavior of targeted NV within the vascular and tumor compartments, an area of particular importance. While we list “elementary” phenomena related to different level of complexity of delivery to cancer, we also stress importance of multi-scale modeling and bottom-up systems biology approach. PMID:18200527

  14. Single compartment drug delivery

    PubMed Central

    Cima, Michael J.; Lee, Heejin; Daniel, Karen; Tanenbaum, Laura M.; Mantzavinou, Aikaterini; Spencer, Kevin C.; Ong, Qunya; Sy, Jay C.; Santini, John; Schoellhammer, Carl M.; Blankschtein, Daniel; Langer, Robert S.

    2014-01-01

    Drug design is built on the concept that key molecular targets of disease are isolated in the diseased tissue. Systemic drug administration would be sufficient for targeting in such a case. It is, however, common for enzymes or receptors that are integral to disease to be structurally similar or identical to those that play important biological roles in normal tissues of the body. Additionally, systemic administration may not lead to local drug concentrations high enough to yield disease modification because of rapid systemic metabolism or lack of sufficient partitioning into the diseased tissue compartment. This review focuses on drug delivery methods that physically target drugs to individual compartments of the body. Compartments such as the bladder, peritoneum, brain, eye and skin are often sites of disease and can sometimes be viewed as “privileged,” since they intrinsically hinder partitioning of systemically administered agents. These compartments have become the focus of a wide array of procedures and devices for direct administration of drugs. We discuss the rationale behind single compartment drug delivery for each of these compartments, and give an overview of examples at different development stages, from the lab bench to phase III clinical trials to clinical practice. We approach single compartment drug delivery from both a translational and a technological perspective. PMID:24798478

  15. Novel antigen delivery systems.

    PubMed

    Trovato, Maria; De Berardinis, Piergiuseppe

    2015-08-12

    Vaccines represent the most relevant contribution of immunology to human health. However, despite the remarkable success achieved in the past years, many vaccines are still missing in order to fight important human pathologies and to prevent emerging and re-emerging diseases. For these pathogens the known strategies for making vaccines have been unsuccessful and thus, new avenues should be investigated to overcome the failure of clinical trials and other important issues including safety concerns related to live vaccines or viral vectors, the weak immunogenicity of subunit vaccines and side effects associated with the use of adjuvants. A major hurdle of developing successful and effective vaccines is to design antigen delivery systems in such a way that optimizes antigen presentation and induces broad protective immune responses. Recent advances in vector delivery technologies, immunology, vaccinology and system biology, have led to a deeper understanding of the molecular and cellular mechanisms by which vaccines should stimulate both arms of the adaptive immune responses, offering new strategies of vaccinations. This review is an update of current strategies with respect to live attenuated and inactivated vaccines, DNA vaccines, viral vectors, lipid-based carrier systems such as liposomes and virosomes as well as polymeric nanoparticle vaccines and virus-like particles. In addition, this article will describe our work on a versatile and immunogenic delivery system which we have studied in the past decade and which is derived from a non-pathogenic prokaryotic organism: the "E2 scaffold" of the pyruvate dehydrogenase complex from Geobacillus stearothermophilus. PMID:26279977

  16. Transmembrane heme delivery systems

    PubMed Central

    Goldman, Barry S.; Beck, David L.; Monika, Elizabeth M.; Kranz, Robert G.

    1998-01-01

    Heme proteins play pivotal roles in a wealth of biological processes. Despite this, the molecular mechanisms by which heme traverses bilayer membranes for use in biosynthetic reactions are unknown. The biosynthesis of c-type cytochromes requires that heme is transported to the bacterial periplasm or mitochondrial intermembrane space where it is covalently ligated to two reduced cysteinyl residues of the apocytochrome. Results herein suggest that a family of integral membrane proteins in prokaryotes, protozoans, and plants act as transmembrane heme delivery systems for the biogenesis of c-type cytochromes. The complete topology of a representative from each of the three subfamilies was experimentally determined. Key histidinyl residues and a conserved tryptophan-rich region (designated the WWD domain) are positioned at the site of cytochrome c assembly for all three subfamilies. These histidinyl residues were shown to be essential for function in one of the subfamilies, an ABC transporter encoded by helABCD. We believe that a directed heme delivery pathway is vital for the synthesis of cytochromes c, whereby heme iron is protected from oxidation via ligation to histidinyl residues within the delivery proteins. PMID:9560218

  17. Waste Feed Delivery Transfer System Analysis

    SciTech Connect

    JULYK, L.J.

    2000-05-05

    This document provides a documented basis for the required design pressure rating and pump pressure capacity of the Hanford Site waste-transfer system in support of the waste feed delivery to the privatization contractor for vitrification. The scope of the analysis includes the 200 East Area double-shell tank waste transfer pipeline system and the associated transfer system pumps for a11 Phase 1B and Phase 2 waste transfers from AN, AP, AW, AY, and A2 Tank Farms.

  18. Air Pollution and Human Health

    ERIC Educational Resources Information Center

    Lave, Lester B.; Seskin, Eugene P.

    1970-01-01

    Reviews studies statistically relating air pollution to mortality and morbidity rates for respiratory, and cardiovascular diseases, cancer and infant mortality. Some data recalculated. Estimates 50 percent air pollution reduction will save 4.5 percent (2080 million dollars per year) of all economic loss (hospitalization, income loss) associated…

  19. Sustained Inflation and Its Role in the Delivery Room Management of Preterm Infants.

    PubMed

    Lista, Gianluca; La Verde, Paola Azzurra; Castoldi, Francesca

    2016-01-01

    A noninvasive approach in the delivery room in place of intubation and mechanical ventilation can reduce rates of bronchopulmonary dysplasia and death. Nevertheless, the rate of nasal continuous positive airway pressure failure still remains high. In order to prevent lung injury and to enhance the success of continuous positive airway pressure, sustained inflation (administration by face mask or nasopharyngeal tube of a high peak pressure of 20-25 cm H2O, maintained for 10-15 s) has been recently proposed to establish an early and efficient functional residual capacity in the delivery room. Sustained inflation is an intriguing therapy, although the results of clinical trials are controversial in terms of respiratory outcomes. A critical role in the success of sustained inflation could be the presence of open or closed glottis and the contribution of spontaneous breathing that allows air to enter the lungs during the maneuver. Recent neonatal resuscitation guidelines suggest that sustained inflation may be considered in individual clinical circumstances or research settings. PMID:27251566

  20. Air Pollution

    MedlinePlus

    ... tobacco smoke. How is air pollution linked to climate change? While climate change is a global process, it ... ozone levels are also a concern. Impacts of Climate Change on Human Health in the United States: A ...

  1. Air Apparent.

    ERIC Educational Resources Information Center

    Harbster, David A.

    1988-01-01

    Explains the principle upon which a barometer operates. Describes how to construct two barometric devices for use in the classroom that show air's changing pressure. Cites some conditions for predicting weather. (RT)

  2. Maternal and neonatal complications of elective early-term deliveries.

    PubMed

    Jensen, Jani R; White, Wendy M; Coddington, Charles C

    2013-11-01

    Approximately 10% to 15% of all deliveries in the United States are performed before 39 completed weeks of gestation without a true medical indication for early delivery, despite long-standing recommendations against this practice. Early-term deliveries are those that occur between 3707 and 3867 weeks. It is now recognized that maternal and neonatal complications have increased for deliveries that occur at early- vs late-term gestation. The reasons for the increase in the rate of elective early-term deliveries are unclear but likely involve both patient and physician factors. Various strategies have been used to increase awareness of the morbidities associated with the practice of elective early-term delivery and to reduce its frequency. Insurers and quality accrediting agencies are increasingly holding hospitals accountable for their rates of elective early-term deliveries, and this pressure will likely continue to lead to widespread change in the practice of obstetrics. The interventions to increase adherence to evidence-based medicine guidelines that are described within this review may also be applicable to other areas of medicine. PMID:24182707

  3. Microencapsulation: A promising technique for controlled drug delivery

    PubMed Central

    Singh, M.N.; Hemant, K.S.Y.; Ram, M.; Shivakumar, H.G.

    2010-01-01

    Microparticles offer various significant advantages as drug delivery systems, including: (i) an effective protection of the encapsulated active agent against (e.g. enzymatic) degradation, (ii) the possibility to accurately control the release rate of the incorporated drug over periods of hours to months, (iii) an easy administration (compared to alternative parenteral controlled release dosage forms, such as macro-sized implants), and (iv) Desired, pre-programmed drug release profiles can be provided which match the therapeutic needs of the patient. This article gives an overview on the general aspects and recent advances in drug-loaded microparticles to improve the efficiency of various medical treatments. An appropriately designed controlled release drug delivery system can be a foot ahead towards solving problems concerning to the targeting of drug to a specific organ or tissue, and controlling the rate of drug delivery to the target site. The development of oral controlled release systems has been a challenge to formulation scientist due to their inability to restrain and localize the system at targeted areas of gastrointestinal tract. Microparticulate drug delivery systems are an interesting and promising option when developing an oral controlled release system. The objective of this paper is to take a closer look at microparticles as drug delivery devices for increasing efficiency of drug delivery, improving the release profile and drug targeting. In order to appreciate the application possibilities of microcapsules in drug delivery, some fundamental aspects are briefly reviewed. PMID:21589795

  4. [Assistance to delivery according to hospital classification].

    PubMed

    Lopez-escobar, G; Daza-parada, L; Riano-gamboa, G; Fortney, J

    1979-06-01

    Between March and October 1977 40 urban Colombian hospitals participated in an evaluation of services given to women with high risk pregnancies. The purpose of the study was to find out whether high risk cases go to the more appropriate and better equipped hospitals. A total of 13,450 deliveries were observed at random, i.e. 8.3% of all deliveries in all 40 hospitals during the same time. Social, cultural, and clinical characteristics of mothers and infants were carefully recorded. It was found that Social Security hospitals had the lowest number of high risk patients, a moderate number of surgical interventions, and the lowest maternal and perinatal mortality rate. On the other hand, average size hospitals serviced a larger number of high risk patients, had the highest rate of surgical intervention and of perinatal mortality, and a moderate maternal mortality rate. University hospitals, with the highest concentration of high risk patients and with a moderate incidence of surgical interventions, had a moderate rate of perinatal mortality, and a high rate of maternal mortality. Obviously not all high risk patients were serviced by the best equipped hospitals and by the best prepared personnel, which resulted in a high rate of maternal-infant morbidity and mortality. It would be necessary to reorganize all available services in a more functional way, so that high risk patients can be assisted and treated in the most appropriate environment. PMID:12310258

  5. 36 CFR 1002.17 - Aircraft and air delivery.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... the Federal Aviation Administration as found in 14 CFR chapter I. (e) The operation or use of hovercraft is prohibited. (f) Violation of the terms and conditions of a permit issued in accordance...

  6. Unimpeded air velocity profiles of air-assisted five-port sprayer

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A capability that relies on tree structure information to control liquid and air flow rates is the preferential design in the development of variable-rate orchard and nursery sprayers. Unimpeded air jet velocities from an air assisted, five-port sprayer in an open field were measured at four height...

  7. A Well-Mixed Computational Model for Estimating Room Air Levels of Selected Constituents from E-Vapor Product Use

    PubMed Central

    Rostami, Ali A.; Pithawalla, Yezdi B.; Liu, Jianmin; Oldham, Michael J.; Wagner, Karl A.; Frost-Pineda, Kimberly; Sarkar, Mohamadi A.

    2016-01-01

    Concerns have been raised in the literature for the potential of secondhand exposure from e-vapor product (EVP) use. It would be difficult to experimentally determine the impact of various factors on secondhand exposure including, but not limited to, room characteristics (indoor space size, ventilation rate), device specifications (aerosol mass delivery, e-liquid composition), and use behavior (number of users and usage frequency). Therefore, a well-mixed computational model was developed to estimate the indoor levels of constituents from EVPs under a variety of conditions. The model is based on physical and thermodynamic interactions between aerosol, vapor, and air, similar to indoor air models referred to by the Environmental Protection Agency. The model results agree well with measured indoor air levels of nicotine from two sources: smoking machine-generated aerosol and aerosol exhaled from EVP use. Sensitivity analysis indicated that increasing air exchange rate reduces room air level of constituents, as more material is carried away. The effect of the amount of aerosol released into the space due to variability in exhalation was also evaluated. The model can estimate the room air level of constituents as a function of time, which may be used to assess the level of non-user exposure over time. PMID:27537903

  8. A Well-Mixed Computational Model for Estimating Room Air Levels of Selected Constituents from E-Vapor Product Use.

    PubMed

    Rostami, Ali A; Pithawalla, Yezdi B; Liu, Jianmin; Oldham, Michael J; Wagner, Karl A; Frost-Pineda, Kimberly; Sarkar, Mohamadi A

    2016-01-01

    Concerns have been raised in the literature for the potential of secondhand exposure from e-vapor product (EVP) use. It would be difficult to experimentally determine the impact of various factors on secondhand exposure including, but not limited to, room characteristics (indoor space size, ventilation rate), device specifications (aerosol mass delivery, e-liquid composition), and use behavior (number of users and usage frequency). Therefore, a well-mixed computational model was developed to estimate the indoor levels of constituents from EVPs under a variety of conditions. The model is based on physical and thermodynamic interactions between aerosol, vapor, and air, similar to indoor air models referred to by the Environmental Protection Agency. The model results agree well with measured indoor air levels of nicotine from two sources: smoking machine-generated aerosol and aerosol exhaled from EVP use. Sensitivity analysis indicated that increasing air exchange rate reduces room air level of constituents, as more material is carried away. The effect of the amount of aerosol released into the space due to variability in exhalation was also evaluated. The model can estimate the room air level of constituents as a function of time, which may be used to assess the level of non-user exposure over time. PMID:27537903

  9. Reduced bleed air extraction for DC-10 cabin air conditioning

    NASA Technical Reports Server (NTRS)

    Newman, W. H.; Viele, M. R.; Hrach, F. J.

    1980-01-01

    It is noted that a significant fuel savings can be achieved by reducing bleed air used for cabin air conditioning. Air in the cabin can be recirculated to maintain comfortable ventilation rates but the quality of the air tends to decrease due to entrainment of smoke and odors. Attention is given to a development system designed and fabricated under the NASA Engine Component Improvement Program to define the recirculation limit for the DC-10. It is shown that with the system, a wide range of bleed air reductions and recirculation rates is possible. A goal of 0.8% fuel savings has been achieved which results from a 50% reduction in bleed extraction from the engine.

  10. Fluid delivery from infusion-pump syringes.

    PubMed

    Carl, J L; Erstad, B L; Murphy, J E; Slack, M K

    1995-07-01

    Fluid-delivery rates of five small-volume infusion-pump syringes were compared. The study consisted of a comparison of the infusion-pump syringes in their respective infusion pumps (1) set for continuous delivery at 1 mL/hr, (2) set for continuous delivery at 3 mL/hr, and (3) set to deliver 1-mL bolus volumes during continuous delivery at 4 mL/hr. The Life-care prefilled 30-mL syringe (Abbott), the DBL 30-mL syringe no. 770205 (DBL Inc.), and the Pump-Jet 30-mL syringe no. 1931 (International Medication Systems) were tested in the Lifecare PCA Plus II infusion pump no. 4100 (Abbott). The 30-mL Pump-Jet syringe no. 1911 (International Medication Systems) and the DBL 30-mL syringe no. 709700 (DBL Inc.) were tested in the Stratofuse PCA infusion pump (Baxter). The infusion pumps were set to deliver fluid continuously at 1 mL/hr for 30 hours, and the solutions were collected separately and weighed. The procedure was repeated with the infusion rate set at 3 mL/hr for 10 hours. For the third part of the study, each syringe was tested to deliver 1-mL boluses with 0, 5, 15, and 25 mL removed from the syringe. The solutions were collected and weighed before and after each bolus was delivered. The volume of solution collected was calculated by using the specific gravity of the solution. The syringes delivered significantly different volumes during the first hour of infusion at both the 1- and 3-mL/hr rates. Differences also existed across time for most of the syringes. Bolus volumes varied greatly after infusion of 0 or 5 mL of fluid but were acceptable for the remainder of the infusions.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7671041

  11. Air bearing vacuum seal assembly

    DOEpatents

    Booth, Rex

    1978-01-01

    An air bearing vacuum seal assembly capable of rotating at the speed of several thousand revolutions per minute using an air cushion to prevent the rotating and stationary parts from touching, and a two stage differential pumping arrangement to maintain the pressure gradient between the air cushion and the vacuum so that the leak rate into the vacuum is, for example, less than 1 .times. 10.sup.-4 Pa m.sup.3 /s. The air bearing vacuum seal has particular application for mounting rotating targets to an evacuated accelerator beam tube for bombardment of the targets with high-power charged particle beams in vacuum.

  12. Novel antigen delivery systems

    PubMed Central

    Trovato, Maria; Berardinis, Piergiuseppe De

    2015-01-01

    Vaccines represent the most relevant contribution of immunology to human health. However, despite the remarkable success achieved in the past years, many vaccines are still missing in order to fight important human pathologies and to prevent emerging and re-emerging diseases. For these pathogens the known strategies for making vaccines have been unsuccessful and thus, new avenues should be investigated to overcome the failure of clinical trials and other important issues including safety concerns related to live vaccines or viral vectors, the weak immunogenicity of subunit vaccines and side effects associated with the use of adjuvants. A major hurdle of developing successful and effective vaccines is to design antigen delivery systems in such a way that optimizes antigen presentation and induces broad protective immune responses. Recent advances in vector delivery technologies, immunology, vaccinology and system biology, have led to a deeper understanding of the molecular and cellular mechanisms by which vaccines should stimulate both arms of the adaptive immune responses, offering new strategies of vaccinations. This review is an update of current strategies with respect to live attenuated and inactivated vaccines, DNA vaccines, viral vectors, lipid-based carrier systems such as liposomes and virosomes as well as polymeric nanoparticle vaccines and virus-like particles. In addition, this article will describe our work on a versatile and immunogenic delivery system which we have studied in the past decade and which is derived from a non-pathogenic prokaryotic organism: the “E2 scaffold” of the pyruvate dehydrogenase complex from Geobacillus stearothermophilus. PMID:26279977

  13. Anemia and Oxygen Delivery.

    PubMed

    Bliss, Stuart

    2015-09-01

    Clinical assessment of tissue oxygenation is challenging. Anemia reflects a decreased oxygen carrying capacity of the blood and its significance in the perioperative setting relates largely to the associated risk of insufficient oxygen delivery and cellular hypoxia. Until meaningful clinical measures of tissue oxygenation are available in veterinary practice, clinicians must rely on evaluation of a patient's hemodynamic and ventilatory performance, along with biochemical and hemogasometric measurements. Blood transfusion is used commonly for treatment of perioperative anemia, and may improve tissue oxygenation by normalizing the rheologic properties of blood and enhancing perfusion, independent of increases in oxygen carrying capacity. PMID:26033442

  14. DELIVERY OF THERAPEUTIC PROTEINS

    PubMed Central

    Pisal, Dipak S.; Kosloski, Matthew P.; Balu-Iyer, Sathy V.

    2009-01-01

    The safety and efficacy of protein therapeutics are limited by three interrelated pharmaceutical issues, in vitro and in vivo instability, immunogenicity and shorter half-lives. Novel drug modifications for overcoming these issues are under investigation and include covalent attachment of poly(ethylene glycol) (PEG), polysialic acid, or glycolic acid, as well as developing new formulations containing nanoparticulate or colloidal systems (e.g. liposomes, polymeric microspheres, polymeric nanoparticles). Such strategies have the potential to develop as next generation protein therapeutics. This review includes a general discussion on these delivery approaches. PMID:20049941

  15. Note: Pneumatically modulated liquid delivery with feedback control

    NASA Astrophysics Data System (ADS)

    Field, C. R.; Terray, A. V.; Lubrano, A. L.; Rogers, D. A.; Hart, S. J.; Rose-Pehrsson, S. L.

    2012-07-01

    We present the design and characterization of a pneumatically driven liquid delivery system using an embedded microcontroller with feedback control capable of maintaining a stable, constant flow rate over several hours of operation. Flow rates with relative standard deviations less than 1% were achieved and compared to a typical laboratory syringe pump.

  16. A Controlled Drug-Delivery Experiment Using Alginate Beads

    ERIC Educational Resources Information Center

    Farrell, Stephanie; Vernengo, Jennifer

    2012-01-01

    This paper describes a simple, cost-effective experiment which introduces students to drug delivery and modeling using alginate beads. Students produce calcium alginate beads loaded with drug and measure the rate of release from the beads for systems having different stir rates, geometries, extents of cross-linking, and drug molecular weight.…

  17. Radioaerosol delivery and clearance in patients with respiratory failure

    SciTech Connect

    Jacobs, M.P.; Tennenberg, S.D.; Baughman, R.P.

    1987-12-01

    A technique for radioaerosol delivery to patients requiring mechanical ventilation is described. Ventilation images and pulmonary radioaerosol clearance rates were successfully obtained in 35 patients regardless of ventilator type or level of positive end-expiratory pressure (PEEP). Those patients with noncardiogenic pulmonary edema (NPE) had significantly increased clearance rates relative to those patients in whom NPE was not present.

  18. Polymers for Drug Delivery Systems

    PubMed Central

    Liechty, William B.; Kryscio, David R.; Slaughter, Brandon V.; Peppas, Nicholas A.

    2012-01-01

    Polymers have played an integral role in the advancement of drug delivery technology by providing controlled release of therapeutic agents in constant doses over long periods, cyclic dosage, and tunable release of both hydrophilic and hydrophobic drugs. From early beginnings using off-the-shelf materials, the field has grown tremendously, driven in part by the innovations of chemical engineers. Modern advances in drug delivery are now predicated upon the rational design of polymers tailored for specific cargo and engineered to exert distinct biological functions. In this review, we highlight the fundamental drug delivery systems and their mathematical foundations and discuss the physiological barriers to drug delivery. We review the origins and applications of stimuli-responsive polymer systems and polymer therapeutics such as polymer-protein and polymer-drug conjugates. The latest developments in polymers capable of molecular recognition or directing intracellular delivery are surveyed to illustrate areas of research advancing the frontiers of drug delivery. PMID:22432577

  19. MODIFICATION AND CHARACTERIZATION OF DRY MATERIAL FEEDER FOR DELIVERY OF RED AND VIOLET DYE MIXTURES

    EPA Science Inventory

    Uniform delivery of dry material for stable concentrations of aerosols in inhalation exposure chambers is essential in inhalation experiments. his paper characterizes an AccuRate dry material feeder with modifications, for different helix sizes, actuation rates, nozzle types and ...

  20. Optimized regional caching for on-demand data delivery

    NASA Astrophysics Data System (ADS)

    Eager, Derek L.; Ferris, Michael C.; Vernon, Mary K.

    1998-12-01

    Systems for on-demand delivery of large, widely-shared data can use several techniques to improve cost/performance, including: multicast data delivery, segmented data delivery, and regional (or proxy) servers that cache some of the data close to the clients. This paper makes three contributions to the state-of-the-art design of such systems. First, we show how segmented multicast delivery techniques, in particular the recently proposed high-performance dynamic skyscraper scheme, can be modified to allow each object to be partially or fully cached at regional servers. The new partitioned delivery architecture supports shared delivery between the regional and remote servers and improves performance even if one server delivers the entire object. The second contribution is an analytic model that can be solved to determine the full/partial object caching strategy that minimizes delivery cost in the context of a system that has homogeneous regional servers. Finally, results in the paper illustrate the use of the model and provide insight into how the optimal caching strategy is influenced by key system and workload parameters, including client request rate, the relative severity of the disk bandwidth and storage capacity constraints at the regional servers, and the relative costs of regional and remote delivery. Two important conclusions from the results are: (1) it is often cost-effective to cache the initial segments of many data objects rather than the complete data for fewer objects, and (2) the partitioned delivery architecture and caching partial objects can each greatly reduce delivery cost.