WorldWideScience

Sample records for air pressure

  1. IceBridge Paroscientific L0 Pressure Altimeter Raw Air Pressure

    Data.gov (United States)

    National Aeronautics and Space Administration — The NASA IceBridge Paroscientific L0 Pressure Altimeter Raw Air Pressure (IAPRS0) data set contains air pressure readings taken over Antarctica using the...

  2. Noncontact Monitoring of Respiration by Dynamic Air-Pressure Sensor.

    Science.gov (United States)

    Takarada, Tohru; Asada, Tetsunosuke; Sumi, Yoshihisa; Higuchi, Yoshinori

    2015-01-01

    We have previously reported that a dynamic air-pressure sensor system allows respiratory status to be visually monitored for patients in minimally clothed condition. The dynamic air-pressure sensor measures vital information using changes in air pressure. To utilize this device in the field, we must clarify the influence of clothing conditions on measurement. The present study evaluated use of the dynamic air-pressure sensor system as a respiratory monitor that can reliably detect change in breathing patterns irrespective of clothing. Twelve healthy volunteers reclined on a dental chair positioned horizontally with the sensor pad for measuring air-pressure signals corresponding to respiration placed on the seat back of the dental chair in the central lumbar region. Respiratory measurements were taken under 2 conditions: (a) thinly clothed (subject lying directly on the sensor pad); and (b) thickly clothed (subject lying on the sensor pad covered with a pressure-reducing sheet). Air-pressure signals were recorded and time integration values for air pressure during each expiration were calculated. This information was compared with expiratory tidal volume measured simultaneously by a respirometer connected to the subject via face mask. The dynamic air-pressure sensor was able to receive the signal corresponding to respiration regardless of clothing conditions. A strong correlation was identified between expiratory tidal volume and time integration values for air pressure during each expiration for all subjects under both clothing conditions (0.840-0.988 for the thinly clothed condition and 0.867-0.992 for the thickly clothed condition). These results show that the dynamic air-pressure sensor is useful for monitoring respiratory physiology irrespective of clothing.

  3. Prenatal air pollution exposure and newborn blood pressure

    NARCIS (Netherlands)

    van Rossem, Lenie; Rifas-Shiman, Sheryl L.; Melly, Steven J.; Kloog, Itai; Luttmann-Gibson, Heike; Zanobetti, Antonella; Coull, Brent A.; Schwartz, Joel D.; Mittleman, Murray A.; Oken, Emily; Gillman, Matthew W.; Koutrakis, Petros; Gold, Diane R.

    2015-01-01

    Background: Air pollution exposure has been associated with increased blood pressure in adults. oBjective: We examined associations of antenatal exposure to ambient air pollution with newborn systolic blood pressure (SBP). Methods: We studied 1,131 mother–infant pairs in a Boston, Massachusetts, are

  4. Measuring air pressure with a polymeric gas sensor

    Directory of Open Access Journals (Sweden)

    Juliana R. Cordeiro

    2010-01-01

    Full Text Available In this communication we describe the application of a conductive polymer gas sensor as an air pressure sensor. The device consists of a thin doped poly(4'-hexyloxy-2,5-biphenylene ethylene (PHBPE film deposited on an interdigitated metallic electrode. The sensor is cheap, easy to fabricate, lasts for several months, and is suitable for measuring air pressures in the range between 100 and 700 mmHg.

  5. Experimental Study on Coal-Breaking Pressure for Compressed Air

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Based on lab model experiments and through the limit analysis, the theoretical formula of calculauoncoal-breaking pressure with compressed air was derived. The experimental result shows that blasting pressure mustexceed 84.0 MPa to break coal with compressive strength of 13.2 MPa. The research provides an important theoretical basis for the design of airshooting mining and industrial tests.

  6. Dirty Air, High Blood Pressure Linked

    Institute of Scientific and Technical Information of China (English)

    应树道

    2001-01-01

    贵刊去年第6期曾刊登一短文,题目是:盐,迫升血压之元凶。读了该文,我开始严格控制每日的食盐摄入量,再附以药物治疗,血压果然趋于平稳。近日上网,遇一奇文,意思是人的血压与空气污染状况有涉!根据对2600个成年人的调查,得出了这样的结论:Pollution may cause changes in the part of the nervous system that controls blood pressure.文章又同时说明:Exactly how pollution might cause blood pressure to climb remains unclear.人体之奥妙由此可见一斑。

  7. Inverse association between air pressure and rheumatoid arthritis synovitis.

    Directory of Open Access Journals (Sweden)

    Chikashi Terao

    Full Text Available Rheumatoid arthritis (RA is a bone destructive autoimmune disease. Many patients with RA recognize fluctuations of their joint synovitis according to changes of air pressure, but the correlations between them have never been addressed in large-scale association studies. To address this point we recruited large-scale assessments of RA activity in a Japanese population, and performed an association analysis. Here, a total of 23,064 assessments of RA activity from 2,131 patients were obtained from the KURAMA (Kyoto University Rheumatoid Arthritis Management Alliance database. Detailed correlations between air pressure and joint swelling or tenderness were analyzed separately for each of the 326 patients with more than 20 assessments to regulate intra-patient correlations. Association studies were also performed for seven consecutive days to identify the strongest correlations. Standardized multiple linear regression analysis was performed to evaluate independent influences from other meteorological factors. As a result, components of composite measures for RA disease activity revealed suggestive negative associations with air pressure. The 326 patients displayed significant negative mean correlations between air pressure and swellings or the sum of swellings and tenderness (p = 0.00068 and 0.00011, respectively. Among the seven consecutive days, the most significant mean negative correlations were observed for air pressure three days before evaluations of RA synovitis (p = 1.7 × 10(-7, 0.00027, and 8.3 × 10(-8, for swellings, tenderness and the sum of them, respectively. Standardized multiple linear regression analysis revealed these associations were independent from humidity and temperature. Our findings suggest that air pressure is inversely associated with synovitis in patients with RA.

  8. Tongue-Palate Contact Pressure, Oral Air Pressure, and Acoustics of Clear Speech

    Science.gov (United States)

    Searl, Jeff; Evitts, Paul M.

    2013-01-01

    Purpose: The authors compared articulatory contact pressure (ACP), oral air pressure (Po), and speech acoustics for conversational versus clear speech. They also assessed the relationship of these measures to listener perception. Method: Twelve adults with normal speech produced monosyllables in a phrase using conversational and clear speech.…

  9. Horizontal high-pressure air injection well construction and operation

    Energy Technology Data Exchange (ETDEWEB)

    Hume, J. [Continental Resources Inc., ND (United States)

    2005-07-01

    This paper discussed the design and operational challenges of a horizontal high-pressure air injection well currently in use at the Cedar Hill Red River B field in North Dakota. The field was developed in 1994, using horizontal wells oriented from the northeast to the southwest corners of each section on 640 acre spacing. In March of 2001, the field was unitized resulting in a horizontal waterflood project and a 320 acre horizontal high pressure air injection project. Extreme temperatures and pressures occurring in the reservoir from the combustion processes associated with high pressure air injection have resulted in several challenges. Reservoir and fluid properties of the field were presented, as well as a type log. Details of the Buffalo and Cedar Hills field were also provided, with a comparison of horizontal and vertical patterns. A light oil displacement process was reviewed, with details of tubing leak corrosion, packer seal and detonation failures. Burn front exposure to casing was discussed, and a wellbore diagram was provided. Various horizontal conversions were discussed. A description of the Cedar Hills Compressor Station and compression trains was provided. It was concluded that knowledge gained from 25 years of vertical high pressure air injection experience has been successfully incorporated to create a safe and durable design. 1 tab., 16 figs.

  10. RHELP (Regenerative High Efficiency Low Pressure) Air Purification System

    Science.gov (United States)

    2009-06-18

    4 (3), 269. 10. Allen, M. D. and Raabe, O. G., "Re-evaluation of millikan’s oil drop data for the motion of small particles in air," Journal of...rigorous physical filtration testing for collection efficiency, pressure drop , most penetrating particle size, and microwave sensitivity, among other...increased quality factor. More importantly, the synthesized filters were found to exceed military standards for HEPA filter with lower pressure drop . This

  11. Predicted thermal superluminescence in low-pressure air

    CERN Document Server

    Aramyan, A R; Galechyan, G A; Mangasaryan, N R; Nersisyan, H B

    2009-01-01

    It is shown that due to the dissociation of the molecular oxygen it is possible to obtain inverted population in low pressure air by heating. As a result of the quenching of the corresponding levels of the atomic oxygen the thermal superluminescent radiation is generated. It has been found that the threshold of the overpopulation is exceeded at the air temperature 2300-3000 K. Using this effect a possible mechanism for the generation of the flashes of the radiation in air observed on the airframe of the space shuttle during its descent and reentry in the atmosphere is suggested.

  12. Maximum Pressure Evaluation during Expulsion of Entrapped Air from Pressurized Pipelines

    Directory of Open Access Journals (Sweden)

    Diana Maria Bucur

    2017-01-01

    Full Text Available Pressurized pipeline systems may have a wide operating regime. This paper presents the experimental analysis of the transient flow in a horizontal pipe containing an air pocket, which allows the ventilation of the air after the pressurization of the hydraulic system, through an orifice placed at the downstream end. The measurements are made on a laboratory set-up, for different supply pressures and various geometries of water column length, air pocket and expulsion orifice diameter. Dimensional analysis is carried out in order to determine a relation between the parameters influencing the maximum pressure value. A two equations model is obtained and a criterion is established for their use. The equations are validated with experimental data from the present laboratory set-up and with other data available in the literature. The results presented as non-dimensional quantities variations show a good agreement with the previous experimental and analytical researches.

  13. The Jar Magic--Instructional Activities for Teaching Air Pressure

    Science.gov (United States)

    Ku, Bing-Hong; Chen, Chyong-Sun

    2013-01-01

    There are a variety of impressive activities designed for teaching the concept of air pressure to junior high school students. Water, glasses, balloons, plastic bottles, and suction cups are some of the items commonly used in these experiments. For example, if we take a glass of water, cover it with a piece of cardboard, and invert the glass,…

  14. Pneumomediastinum following high pressure air injection to the hand.

    LENUS (Irish Health Repository)

    Kennedy, J

    2012-02-01

    We present the case of a patient who developed pneumomediastinum after high pressure air injection to the hand. To our knowledge this is the first reported case of pneumomediastinum where the gas injection site was the thenar eminence. Fortunately the patient recovered with conservative management.

  15. Pneumomediastinum following high pressure air injection to the hand.

    LENUS (Irish Health Repository)

    Kennedy, J

    2010-04-01

    We present the case of a patient who developed pneumomediastinum after high pressure air injection to the hand. To our knowledge this is the first reported case of pneumomediastinum where the gas injection site was the thenar eminence. Fortunately the patient recovered with conservative management.

  16. One-Component Pressure-Temperature Phase Diagrams in the Presence of Air

    Science.gov (United States)

    Andrade-Gamboa, Julio; Martire, Daniel O.; Donati, Edgardo R.

    2010-01-01

    One-component phase diagrams are good approximations to predict pressure-temperature ("P-T") behavior of a substance in the presence of air, provided air pressure is not much higher than the vapor pressure. However, at any air pressure, and from the conceptual point of view, the use of a traditional "P-T" phase diagram is not strictly correct. In…

  17. Generation of subnanosecond electron beams in air at atmospheric pressure

    Science.gov (United States)

    Kostyrya, I. D.; Tarasenko, V. F.; Baksht, E. Kh.; Burachenko, A. G.; Lomaev, M. I.; Rybka, D. V.

    2009-11-01

    Optimum conditions for the generation of runaway electron beams with maximum current amplitudes and densities in nanosecond pulsed discharges in air at atmospheric pressure are determined. A supershort avalanche electron beam (SAEB) with a current amplitude of ˜30 A, a current density of ˜20 A/cm2, and a pulse full width at half maximum (FWHM) of ˜100 ps has been observed behind the output foil of an air-filled diode. It is shown that the position of the SAEB current maximum relative to the voltage pulse front exhibits a time shift that varies when the small-size collector is moved over the foil surface.

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

    Science.gov (United States)

    Shen, Rui; Suuberg, Eric M

    2016-02-01

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

  19. Microcontrolled air-mattress for ulcer by pressure prevention

    Science.gov (United States)

    Pasluosta, Cristian F.; Fontana, Juan M.; Beltramone, Diego A.; Taborda, Ricardo A. M.

    2007-11-01

    An ulcer by pressure is produced when a constant pressure is exerted over the skin. This generates the collapse of the blood vessels and, therefore, a lack in the contribution of the necessary nutrients for the affected zone. As a consequence, the skin deteriorates, eventually causing an ulcer. In order to prevent it, a protocol must be applied to the patient, which is reflected on time and cost of treatment. There are some air mattresses available for this purpose, but whose performance does not fulfill all requirements. The prototype designed in our laboratory is based on the principle of the air mattress. Its objective is to improve on existing technologies and, due to an increased automation, reduce time dedication for personnel in charge of the patient. A clinical experience was made in the local Emergencies Hospital and also in an institution dedicated to aged patients care. In both cases, the results obtained and the comments from the personnel involved were favorable.

  20. Microcontrolled air-mattress for ulcer by pressure prevention

    Energy Technology Data Exchange (ETDEWEB)

    Pasluosta, Cristian F; Fontana, Juan M; Beltramone, Diego A; Taborda, Ricardo A M [Universidad Nacional de Cordoba. Cordoba (Argentina)

    2007-11-15

    An ulcer by pressure is produced when a constant pressure is exerted over the skin. This generates the collapse of the blood vessels and, therefore, a lack in the contribution of the necessary nutrients for the affected zone. As a consequence, the skin deteriorates, eventually causing an ulcer. In order to prevent it, a protocol must be applied to the patient, which is reflected on time and cost of treatment. There are some air mattresses available for this purpose, but whose performance does not fulfill all requirements. The prototype designed in our laboratory is based on the principle of the air mattress. Its objective is to improve on existing technologies and, due to an increased automation, reduce time dedication for personnel in charge of the patient. A clinical experience was made in the local Emergencies Hospital and also in an institution dedicated to aged patients care. In both cases, the results obtained and the comments from the personnel involved were favorable.

  1. Intraoral air pressure and oral air flow under different bleed and bite-block conditions.

    Science.gov (United States)

    Putnam, A H; Shelton, R L; Kastner, C U

    1986-03-01

    Intraoral pressures and oral flows were measured as normal talkers produced /p lambda/ and /si/ under experimental conditions that perturbed the usual aeromechanical production characteristics of the consonants. A translabial pressure-release device was used to bleed off intraoral pressure during /p/. Bite-blocks were used to open the anterior bite artificially during /s/. For /p/, intraoral pressure decreased and translabial air leakage increased as bleed orifice area increased. For /s/, flow increased as the area of sibilant constriction increased, but differential pressure across the /s/ oral constriction did not vary systematically with changes in its area. Flow on postconsonantal vowels /lambda/ and /i/ did not vary systematically across experimental conditions. The data imply that maintenance of perturbed intraoral pressure was more effective when compensatory options included opportunity for increased respiratory drive and structural adjustments at the place of consonant articulation rather than increased respiratory drive alone.

  2. AIR SEPARATION BY PRESSURE SWING ADSORPTION USING SUPERIOR ADSORBENTS

    Energy Technology Data Exchange (ETDEWEB)

    Ralph T. Yang

    2001-08-31

    Li-X zeolite (Si/Al = 1.0) is currently the best sorbent for use in the separation of air by adsorption processes. In particular, pressure swing adsorption (PSA) using zeolite sorbents is being increasingly used for air separation. Silver is also known to strongly affect the adsorptive properties of zeolites; and it is known that thermal vacuum dehydration of silver zeolites leads to the formation of silver clusters within the zeolite. In this work we have synthesized type X zeolites containing Ag and also varying mixtures of Li and Ag. In this project, we developed the Ag-containing zeolite as the best sorbent for air separation. We have also studied Co-ligand compounds as oxygen-selective sorbents. Syntheses, structural characterization and adsorption properties have been performed on all sorbents. The results are described in detail in 5 chapters.

  3. Air Entrainment in Dynamic Wetting: Knudsen Effects and the Influence of Ambient Air Pressure

    CERN Document Server

    Sprittles, James E

    2015-01-01

    Recent experiments on coating flows and liquid drop impact both demonstrate that wetting failures caused by air entrainment can be suppressed by reducing the ambient gas pressure. Here, it is shown that non-equilibrium effects in the gas can account for this behaviour, with ambient pressure reductions increasing the gas' mean free path and hence the Knudsen number $Kn$. These effects first manifest themselves through Maxwell slip at the gas' boundaries so that for sufficiently small $Kn$ they can be incorporated into a continuum model for dynamic wetting flows. The resulting mathematical model contains flow structures on the nano-, micro- and milli-metre scales and is implemented into a computational platform developed specifically for such multiscale phenomena. The coating flow geometry is used to show that for a fixed gas-liquid-solid system (a) the increased Maxwell slip at reduced pressures can substantially delay air entrainment, i.e. increase the `maximum speed of wetting', (b) unbounded maximum speeds ...

  4. Testing of heat exchangers in membrane oxygenators using air pressure.

    Science.gov (United States)

    Hamilton, Carole; Stein, Jutta; Seidler, Rainer; Kind, Robert; Beck, Karin; Tosok, Jürgen; Upterfofel, Jörg

    2006-03-01

    All heat exchangers (HE) in membrane oxygenators are tested by the manufacturer for water leaks during the production phase. However, for safety reasons, it is highly recommended that HEs be tested again before clinical use. The most common method is to attach the heater-cooler to the HE and allow the water to recirculate for at least 10 min, during which time a water leak should be evident. To improve the detection of water leaks, a test was devised using a pressure manometer with an integrated bulb used to pressurize the HE with air. The cardiopulmonary bypass system is set up as per protocol. A pressure manometer adapted to a 1/2" tubing is connected to the water inlet side of the oxygenator. The water outlet side is blocked with a short piece of 1/2" deadend tubing. The HE is pressurized with 250 mmHg for at least 30 sec and observed for any drop. Over the last 2 years, only one oxygenator has been detected with a water leak in which the air-method leaktest was performed. This unit was sent back to the manufacturer who confirmed the failure. Even though the incidence of water leaks is very low, it does occur and it is, therefore, important that all HEs are tested before they are used clinically. This method of using a pressure manometer offers many advantages, as the HE can be tested outside of the operating room (OR), allowing earlier testing of the oxygenator, no water contact is necessary, and it is simple, easy and quick to perform.

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

    Science.gov (United States)

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

    2017-03-01

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

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

    Science.gov (United States)

    Tsuchiya, Naoki; Nakajima, Hiroshi; Hata, Yutaka

    2011-06-01

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

  7. Thermal separation of soil particles from thermal conductivity measurement under various air pressures.

    Science.gov (United States)

    Lu, Sen; Ren, Tusheng; Lu, Yili; Meng, Ping; Zhang, Jinsong

    2017-01-05

    The thermal conductivity of dry soils is related closely to air pressure and the contact areas between solid particles. In this study, the thermal conductivity of two-phase soil systems was determined under reduced and increased air pressures. The thermal separation of soil particles, i.e., the characteristic dimension of the pore space (d), was then estimated based on the relationship between soil thermal conductivity and air pressure. Results showed that under both reduced and increased air pressures, d estimations were significantly larger than the geometrical mean separation of solid particles (D), which suggested that conductive heat transfer through solid particles dominated heat transfer in dry soils. The increased air pressure approach gave d values lower than that of the reduced air pressure method. With increasing air pressure, more collisions between gas molecules and solid surface occurred in micro-pores and intra-aggregate pores due to the reduction of mean free path of air molecules. Compared to the reduced air pressure approach, the increased air pressure approach expressed more micro-pore structure attributes in heat transfer. We concluded that measuring thermal conductivity under increased air pressure procedures gave better-quality d values, and improved soil micro-pore structure estimation.

  8. Thermal separation of soil particles from thermal conductivity measurement under various air pressures

    Science.gov (United States)

    Lu, Sen; Ren, Tusheng; Lu, Yili; Meng, Ping; Zhang, Jinsong

    2017-01-01

    The thermal conductivity of dry soils is related closely to air pressure and the contact areas between solid particles. In this study, the thermal conductivity of two-phase soil systems was determined under reduced and increased air pressures. The thermal separation of soil particles, i.e., the characteristic dimension of the pore space (d), was then estimated based on the relationship between soil thermal conductivity and air pressure. Results showed that under both reduced and increased air pressures, d estimations were significantly larger than the geometrical mean separation of solid particles (D), which suggested that conductive heat transfer through solid particles dominated heat transfer in dry soils. The increased air pressure approach gave d values lower than that of the reduced air pressure method. With increasing air pressure, more collisions between gas molecules and solid surface occurred in micro-pores and intra-aggregate pores due to the reduction of mean free path of air molecules. Compared to the reduced air pressure approach, the increased air pressure approach expressed more micro-pore structure attributes in heat transfer. We concluded that measuring thermal conductivity under increased air pressure procedures gave better-quality d values, and improved soil micro-pore structure estimation.

  9. Pressurized air cathodes for enhanced stability and power generation by microbial fuel cells

    Science.gov (United States)

    He, Weihua; Yang, Wulin; Tian, Yushi; Zhu, Xiuping; Liu, Jia; Feng, Yujie; Logan, Bruce E.

    2016-11-01

    Large differences between the water and air pressure in microbial fuel cells (MFCs) can deform and damage cathodes. To avoid deformation, the cathode air pressure was controlled to balance pressure differences between the air and water. Raising the air pressures from 0 to 10 kPa at a set cathode potential of -0.3 V (versus Ag/AgCl) enhanced cathode performance by 17%, but pressures ≥25 kPa decreased current and resulted in air leakage into the solution. Matching the air pressure with the water pressure avoided cathode deformation and improved performance. The maximum power density increased by 15%, from 1070 ± 20 to 1230 ± 70 mW m-2, with balanced air and water pressures of 10-25 kPa. Oxygen partial pressures ≥12.5 kPa in the cathode compartment maintained the oxygen reduction rate to be within 92 ± 1% of that in ambient air. The use of pressurized air flow through the cathode compartments can enable closer spacing of the cathodes compared to passive gas transfer systems, which could make the reactor design more compact. The energy cost of pressurizing the cathodes was estimated to be smaller than the increase in power that resulted from the use of pressurized cathodes.

  10. Effect of Mixture Pressure and Equivalence Ratio on Detonation Cell Size for Hydrogen-Air Mixtures

    Science.gov (United States)

    2015-06-01

    EFFECT OF MIXTURE PRESSURE AND EQUIVALENCE RATIO ON DETONATION CELL SIZE FOR HYDROGEN -AIR MIXTURES...protection in the United States. AFIT-ENY-MS-15-J-045 EFFECT OF MIXTURE PRESSURE AND EQUIVALENCE RATIO ON DETONATION CELL SIZE FOR HYDROGEN -AIR...DISTRIBUTION UNLIMITED. AFIT-ENY-MS-15-J-045 EFFECT OF MIXTURE PRESSURE AND EQUIVALENCE RATIO ON DETONATION CELL SIZE FOR HYDROGEN -AIR MIXTURES

  11. 30 CFR 56.13015 - Inspection of compressed-air receivers and other unfired pressure vessels.

    Science.gov (United States)

    2010-07-01

    ... other unfired pressure vessels. 56.13015 Section 56.13015 Mineral Resources MINE SAFETY AND HEALTH... and other unfired pressure vessels. (a) Compressed-air receivers and other unfired pressure vessels... applicable chapters of the National Board Inspection Code, a Manual for Boiler and Pressure Vessel...

  12. 30 CFR 57.13015 - Inspection of compressed-air receivers and other unfired pressure vessels.

    Science.gov (United States)

    2010-07-01

    ... other unfired pressure vessels. 57.13015 Section 57.13015 Mineral Resources MINE SAFETY AND HEALTH... receivers and other unfired pressure vessels. (a) Compressed-air receivers and other unfired pressure... the applicable chapters of the National Board Inspection Code, a Manual for Boiler and Pressure...

  13. Field test to study the pressure equilization on air permeable facade elements

    NARCIS (Netherlands)

    Bentum, C.A. van; Kalkman, I.M.; Geurts, C.P.W.

    2014-01-01

    The net wind load on the outer layer of a façade consisting of multiple layers is determined by the external pressure and the cavity pressure. For an air-permeable outer layer, the cavity pressure is dependent on the extent to which the external pressure equalizes over the openings. Minimizing the p

  14. Study of short atmospheric pressure dc glow microdischarge in air

    Science.gov (United States)

    Kudryavtsev, Anatoly; Bogdanov, Eugene; Chirtsov, Alexander; Emelin, Sergey

    2011-10-01

    The results of experiments and simulations of short (without positive column) atmospheric pressure dc glow discharge in air are presented. We used metal steel electrodes with a gap of 5-100 microns. The experimental voltage-current characteristic's (VAC) have a constant or slightly increasing form at low gap. The most stable microdischarges were burning with a flat cathode and rounded anode, when the length of the discharge is automatically established near the minimum of the Paschen curve by changing their binding on the anode. In this case microdischarge was stable and it had growing VAC. For simulations we used 2D fluid model with kinetic description of electrons. We solved the balance equations for the vibrationally- and the electronically-excited states of a nitrogen and oxygen molecules; nitrogen and oxygen atoms; ozone molecule; and different nitrogen and oxygen ions with different plasmochemical reactions between them. Simulations predicted the main regions of the dc glow discharges including cathode and anode sheath and plasma of negative glow, Faraday dark space and transition region. Gas heating plays an important role in shaping the discharge profiles. The results of experiments and simulations of short (without positive column) atmospheric pressure dc glow discharge in air are presented. We used metal steel electrodes with a gap of 5-100 microns. The experimental voltage-current characteristic's (VAC) have a constant or slightly increasing form at low gap. The most stable microdischarges were burning with a flat cathode and rounded anode, when the length of the discharge is automatically established near the minimum of the Paschen curve by changing their binding on the anode. In this case microdischarge was stable and it had growing VAC. For simulations we used 2D fluid model with kinetic description of electrons. We solved the balance equations for the vibrationally- and the electronically-excited states of a nitrogen and oxygen molecules; nitrogen

  15. Behavior of a horizontal air curtain subjected to a vertical pressure gradient

    Science.gov (United States)

    Linden, James; Phelps, LeEllen

    2012-09-01

    We present the details on an experiment to investigate the behavior of an air curtain that is subjected to a transverse pressure gradient. The setup simulates the conditions that will be present in the Advanced Technology Solar Telescope (ATST), a 4-meter solar observatory that will be built on Haleakala, Hawaii. A test rig was built to replicate the region at which the optical path crosses a temperature and pressure boundary between the telescope mount region, which is at the ambient temperature and pressure, and a warmer, pressurized lab space directly below. Use of an air curtain in place of an optically-transmitting window at the interface would allow science observations at a wider range of scientific wavelengths. With the air curtain exhibiting transitional flow behavior across the boundary, and applied pressure gradients of up to 6.5 Pa, we found that the air curtain was able to hold a pressure gradient of 0.25 Pa. As the applied pressure was increased, transient turbulent regions formed at the interface, and predictable flow behavior only occurred in the region closest to the air curtain blower. Computer modeling is used to validate the test data, identify laminar regions of the air curtain where minimal image distortion would occur, and explore the relationship between the applied pressure, effective pressure difference, and air curtain profile.

  16. Molecular dynamics simulations of water on a hydrophilic silica surface at high air pressures

    DEFF Research Database (Denmark)

    Zambrano, H.A.; Walther, Jens Honore; Jaffe, R.L.

    2014-01-01

    of air in water at different pressures. Using the calibrated force field, we conduct MD simulations to study the interface between a hydrophilic silica substrate and water surrounded by air at different pressures. We find that the static water contact angle is independent of the air pressure imposed......Wepresent a force field forMolecular Dynamics (MD) simulations ofwater and air in contactwith an amorphous silica surface. We calibrate the interactions of each species present in the systemusing dedicated criteria such as the contact angle of a water droplet on a silica surface, and the solubility...

  17. A falling-pressure method for measuring air permeability of asphalt in laboratory

    Science.gov (United States)

    Li, Hailong; Jiao, Jiu Jimmy; Luk, Mario

    2004-01-01

    This paper presents a simple analytical solution for estimating air permeability using the test data obtained by a falling-pressure method in laboratory. The perimeter of the column-shaped sample is fixed in a steel cylinder with the upper sample surface open to the atmosphere. The lower surface of the sample and the cylinder form an air chamber. A water manometer is connected to the air chamber to measure the air pressure inside after the chamber is pressurized. The data of pressure versus time in the air chamber are recorded and analyzed. An approximate analytical solution is derived to describe the pressure-time relationship in the air chamber. The air permeability can be easily estimated using the approximate analytical solution based on the linear least-squares fitting to the recorded pressure-time test data. This method is used to estimate the falling-pressure test data of 15 asphalt samples. The agreement between the test data and the analytical prediction is satisfactory for all the samples. To investigate the error caused by the approximate analytical solution, the air permeabilities are also estimated based on fully numerical solutions. The permeability values obtained from analytical and numerical solutions are very close. The maximum relative error is less than 6% for samples with more than five pressure-time records. A quantitative condition is given under which the analytical solution applies with negligible estimation error. Compared with the common, steady-state method for measuring air permeability, the falling-pressure method has its advantages such as simplicity and economy. The steady-state method has to measure the air flux through the sample, while the falling-pressure method does not.

  18. Growth and β-galactosidase activity in cultures of Kluyveromyces marxianus under increased air pressure

    OpenAIRE

    2003-01-01

    Aims: To investigate the effect of total air pressure raise on cell growth and intracellular β-galactosidase activity in batch cultures of Kluyveromyces marxianus CBS 7894. Methods and Results: A pressurized bioreactor was used for K. marxianus batch cultivation under increased air pressure from 1.2 to 6 bar. Under these conditions no inhibition of cell growth was observed. Moreover, the improvement of the oxygen transfer rate (OTR) from the gas to the culture medium by pressuriza...

  19. Impacts of air pressure on the evolution of nanosecond pulse discharge products

    Institute of Scientific and Technical Information of China (English)

    Yu Jin-Lu; He Li-Ming; Ding Wei; Wang Yu-Qian; Du Chun

    2013-01-01

    Based on the nonequilibrium plasma dynamics of air discharge,a dynamic model of zero-dimensional plasma is established by combining the component density equation,the Boltzmann equation,and the energy transfer equation.The evolution properties of nanosecond pulse discharge (NPD) plasma under different air pressures are calculated.The results show that the air pressure has significant impacts on the NPD products and the peak values of particle number density for particles such as O atoms,O3 molecules,N2(A3) molecules in excited states,and NO molecules.It increases at first and then decreases with the increase of air pressure.On the other hand,the peak values of particle number density for N2(B3)and N2(C3) molecules in excited states are only slightly affected by the air pressure.

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

    KAUST Repository

    Ahn, Yongtae

    2014-02-01

    To better understand how air cathode performance is affected by air humidification, microbial fuel cells were operated under different humidity conditions or water pressure conditions. Maximum power density decreased from 1130 ± 30 mW m-2 with dry air to 980 ± 80 mW m -2 with water-saturated air. When the cathode was exposed to higher water pressures by placing the cathode in a horizontal position, with the cathode oriented so it was on the reactor bottom, power was reduced for both with dry (1030 ± 130 mW m-2) and water-saturated (390 ± 190 mW m-2) air. Decreased performance was partly due to water flooding of the catalyst, which would hinder oxygen diffusion to the catalyst. However, drying used cathodes did not improve performance in electrochemical tests. Soaking the cathode in a weak acid solution, but not deionized water, mostly restored performance (960 ± 60 mW m-2), suggesting that there was salt precipitation in the cathode that was enhanced by higher relative humidity or water pressure. These results showed that cathode performance could be adversely affected by both flooding and the subsequent salt precipitation, and therefore control of air humidity and water pressure may need to be considered for long-term MFC operation. © 2013 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

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

    2014-02-01

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

  2. Impact of air pressure on volatile organic compound emissions from a carpet

    Institute of Scientific and Technical Information of China (English)

    高鹏; 邓琴琴; LIN; Chao-hsin; 杨旭东

    2009-01-01

    The measurement of volatile organic compound (VOC) emissions from materials is normally conducted under standard environmental conditions, i.e., (23±1) ℃ temperature, (50±5)% relative humidity, and 0.1 MPa pressure. In order to define VOC emissions in non-standard environmental conditions, it is necessary to study the impact of key environmental parameters on emissions. This paper evaluates the impact of air pressure on VOC emissions from an aircraft carpet. The correlation between air pressure and VOC diffusion coefficient is derived, and the emission model is applied to studying the VOC emissions under pressure conditions of less than 0.1 MPa.

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

    Science.gov (United States)

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

    2016-09-01

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

  4. TAO/TRITON, RAMA, and PIRATA Buoys, Monthly, Barometric (Air) Pressure

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset has monthly Barometric (Air) Pressure data from the TAO/TRITON (Pacific Ocean, http://www.pmel.noaa.gov/tao/), RAMA (Indian Ocean,...

  5. TAO/TRITON, RAMA, and PIRATA Buoys, Quarterly, Barometric (Air) Pressure

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset has quarterly Barometric (Air) Pressure data from the TAO/TRITON (Pacific Ocean, http://www.pmel.noaa.gov/tao/), RAMA (Indian Ocean,...

  6. TAO/TRITON, RAMA, and PIRATA Buoys, 5-Day, Barometric (Air) Pressure

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset has 5-day Barometric (Air) Pressure data from the TAO/TRITON (Pacific Ocean, http://www.pmel.noaa.gov/tao/), RAMA (Indian Ocean,...

  7. TAO/TRITON, RAMA, and PIRATA Buoys, Daily, Barometric (Air) Pressure

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset has daily Barometric (Air) Pressure data from the TAO/TRITON (Pacific Ocean, http://www.pmel.noaa.gov/tao/), RAMA (Indian Ocean,...

  8. Influence of air pressure on mechanical effect of laser plasma shock wave

    Institute of Scientific and Technical Information of China (English)

    Zhang Yu-Zhu; Wang Guang-An; Zhu Jin-Rong; Shen Zhong-Hua; Ni Xiao-Wu; Lu Jian

    2007-01-01

    The influence of air pressure on mechanical effect of laser plasma shock wave in a vacuum chamber produced by a Nd:YAG laser has been studied. The laser pulses with pulse width of 10ns and pulse energy of about 320mJ at 1.06μm wavelength is focused on the aluminium target mounted on a ballistic pendulum, and the air pressure in the chamber changes from 2.8 × 103 to 1.01×105pa. The experimental results show that the impulse coupling coefficient changes as the air pressure and the distance of the target from focus change. The mechanical effects of the plasma shock wave on the target are analysed at different distances from focus and the air pressure.

  9. Working of spontaneously combustible coal seams with automatic air pressure regulation in the excavation field

    Energy Technology Data Exchange (ETDEWEB)

    Golik, A.S.; Churikov, Yu.V.; Troyan, N.P.

    1980-01-01

    A demonstration is made of the effectiveness of using an automatic air pressure control system during the working of spontaneously combustible coal seams in order to control endogenic fires and gas. 2 figures.

  10. NUMERICAL SIMULATION AND ANALYSIS OF PRESSURE PULSATION IN FRANCIS HYDRAULIC TURBINE WITH AIR ADMISSION

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In this article, the three-dimensional unsteady multiphase flow is simulated in the whole passage of Francis hydraulic turbine. The pressure pulsation is predicted and compared with experimental data at positions in the draft tube, in front of runner, guide vanes and at the inlet of the spiral case. The relationship between pressure pulsation in the whole passage and air admission is analyzed. The computational results show: air admission from spindle hole decreases the pressure difference in the horizontal section of draft tube, which in turn decreases the amplitude of low-frequency pressure pulsation in the draft tube; the rotor-stator interaction between the air inlet and the runner increases the blade-frequency pressure pulsation in front of the runner.

  11. Electrical explosion of Al and Ag wires in air at different pressures

    Science.gov (United States)

    Sarkisov, G. S.; Caplinger, J.; Parada, F.; Sotnikov, V. I.

    2016-09-01

    Experiments with electrically exploding fine Al and Ag wires in air demonstrate a strong dependence of the expanding metal core condition and velocity on ambient pressure. Expansion velocity of the wire core varies by 23 times between ˜0.2 km/s and ˜4.6 km/s. The shock-wave velocity at atmospheric pressure is ˜5 km/s and increases to ˜6 km/s when the pressure is decreased to 50 Torr. The condition of the metal core is strongly dependent on material and whether it is expanding into vacuum or against ambient air pressure. Expansion velocity of the fine Al and Ag wires for different surrounding pressures in general agree with Paschen's Law for air gap.

  12. The effect of form pressure on the air void structure of SCC

    DEFF Research Database (Denmark)

    Jensen, Mikkel Vibæk; Hasholt, Marianne Tange; Geiker, Mette Rica

    2005-01-01

    on the air void structure of hardened, air entrained SCC. The subject was examined through laboratory investigations of SCC with two different amounts of air entrainment. The condition in the form was simulated by using containers making it possible to cure concrete under various pressures corresponding...... structure may be estimated by using Boyle-Mariottes law. However, other conditions such as the form filling method might influence....

  13. The Effects of Air Pressure on Spontaneous Otoacoustic Emissions of Lizards

    NARCIS (Netherlands)

    van Dijk, Pim; Manley, Geoffrey A.

    2013-01-01

    Small changes of air pressure outside the eardrum of five lizard species led to changes in frequency, level, and peak width of spontaneous otoacoustic emissions (SOAE). In contrast to humans, these changes generally occurred at very small pressures (<20 mbar). As in humans, SOAE amplitudes were gene

  14. Air pollution, blood pressure, and the risk of hypertensive complications during pregnancy: The generation r study

    NARCIS (Netherlands)

    Hooven, E.H. van den; Kluizenaar, Y. de; Pierik, F.H.; Hofman, A.; Ratingen, S.W. van; Zandveld, P.Y.J.; MacKenbach, J.P.; Steegers, E.A.P.; Miedema, H.M.E.; Jaddoe, V.W.V.

    2011-01-01

    Exposure to air pollution is associated with elevated blood pressure and cardiovascular disease. We assessed the associations of exposure to particulate matter (PM10) and nitrogen dioxide (NO2) levels with blood pressure measured in each trimester of pregnancy and the risks of pregnancy-induced hype

  15. Finding the optimal setting of inflated air pressure for a multi-cell air cushion for wheelchair patients with spinal cord injury.

    Directory of Open Access Journals (Sweden)

    Hamanami K

    2004-02-01

    Full Text Available Pressure distribution patterns of the seating interface on the multi-cell air cushion (ROHO High Profile of 36 adults with spinal cord injury (SCI (Neurological level Th3 -L1 were measured at different air pressure levels by a pressure mat measurement system. Stress distribution relative to the inflated air pressure in the air cushion on the patients' wheelchairs was analyzed to determine the appropriate inflated air pressure of the cushion for patients. The maximum pressure points in all subjects were at the areas of the ischial tuberosities (82 to 347 mmHg. The optimal reduction in interface pressure at the ischial tuberosities was obtained just before bottoming out. The cushion air pressure at that point was between 17 and 42 mmHg, and correlated well to body weight (r = 0.495, P = 0.0021. In contrast, the maximum pressure levels did not correlate to body weight or the Body Mass Index (BMI. Pressure at the ischial area could be reduced, but not eliminated, by adjusting the air pressure. The maximum pressure levels seemed to be related to the shape of the buttocks, especially the amount of soft tissue, and exceeded the defined threshold for pressure ulcers (> 80 g/cm2.

  16. An experimental study of geyser-like flows induced by a pressurized air pocket

    Science.gov (United States)

    Elayeb, I. S.; Leon, A.; Choi, Y.; Alnahit, A. O.

    2015-12-01

    Previous studies argues that the entrapment of pressurized air pockets within combined sewer systems can produce geyser flows, which is an oscillating jetting of a mixture of gas-liquid flows. To verify that pressurized air pockets can effectively produce geysers, laboratory experiments were conducted. However, past experiments were conducted in relatively small-scale apparatus (i.e. maximum φ2" vertical shaft). This study conducted a set of experiments in a larger apparatus. The experimental setup consists of an upstream head tank, a downstream head tank, a horizontal pipe (46.5ft long, φ6") and a vertical pipe (10ft long, φ6"). The initial condition for the experiments is constant flow discharge through the horizontal pipe. The experiments are initiated by injecting an air pocket with pre-determined volume and pressure at the upstream end of the horizontal pipe. The air pocket propagates through the horizontal pipe until it arrives to the vertical shaft, where it is released producing a geyser-like flow. Three flow rates in the horizontal pipe and three injected air pressures were tested. The variables measured were pressure at two locations in the horizontal pipe and two locations in the vertical pipe. High resolution videos at two regions in the vertical shaft were also recorded. To gain further insights in the physics of air-water interaction, the laboratory experiments were complemented with numerical simulations conducted using a commercial 3D CFD model, previously validated with experiments.

  17. Numerical simulation of high pressure release and dispersion of hydrogen into air with real gas model

    Science.gov (United States)

    Khaksarfard, R.; Kameshki, M. R.; Paraschivoiu, M.

    2010-06-01

    Hydrogen is a renewable and clean source of energy, and it is a good replacement for the current fossil fuels. Nevertheless, hydrogen should be stored in high-pressure reservoirs to have sufficient energy. An in-house code is developed to numerically simulate the release of hydrogen from a high-pressure tank into ambient air with more accuracy. Real gas models are used to simulate the flow since high-pressure hydrogen deviates from ideal gas law. Beattie-Bridgeman and Abel Noble equations are applied as real gas equation of state. A transport equation is added to the code to calculate the concentration of the hydrogen-air mixture after release. The uniqueness of the code is to simulate hydrogen in air release with the real gas model. Initial tank pressures of up to 70 MPa are simulated.

  18. Analysis of mine's air leakage based on pressure gradient matrix between nodes

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jian-rang; WANG Hong-gang; WU Feng-liang; CHANG Xin-tan

    2008-01-01

    Air leakage may significantly affect the effectiveness of mine ventilation by in-creasing the cost of ventilation and arousing problems for ventilation management. Fur-thermore, air leakage may accelerate the process of coal spontaneous combustion andcause gas explosion, thus greatly threatens the safety of coat production. The estimationof air leakage, therefore, have great practical significance. For any ventilation system ofcoal mines, there is a defined pattern of pressure gradient which drived the mine air toflow in the network, drives possible air leakage to go shortcut as well. Air leakage mayoccur through ventilation structures such as ventilation doors and fractures of the surroun-dig coal and rock of airways. A concept and the relevent calculation method of the pres-sure gradient matrix was put forward to assist the analysis of potential air leakage routes.A simplified example was used to introduce the application principle of'pressure gradientmatrix in identifying all the potential air leaking routes, which offers a deeper understand-ing over the ventilation system and the prevention of coal spontaneous combustion.

  19. Adding a custom made pressure release valve during air enema for intussusception: A new technique

    Directory of Open Access Journals (Sweden)

    Hosni Morsi Ahmed

    2015-01-01

    Full Text Available Background: Non-surgical reduction remains the first line treatment of choice for intussusception. The major complication of air enema reduction is bowel perforation. The authors developed a custom made pressure release valve to be added to portable insufflation devices, delivering air at pressures accepted as safe for effective reduction of intussusception in children under fluoroscopic guidance. The aim of this study was to develop a custom made pressure release valve that is suitable for the insufflation devices used for air enema reduction of intussusception and to put this valve into regular clinical practice. Materials and Methods: An adjustable, custom made pressure release valve was assembled by the authors using readily available components. The valve was coupled to a simple air enema insufflation device. The device was used for the trial of reduction of intussusception in a prospective study that included 132 patients. Results: The success rate for air enema reduction with the new device was 88.2%. The mean pressure required to achieve complete reduction was 100 mmHg. The insufflation pressure never exceeded the preset value (120 mmHg. Of the successful cases, 58.3% were reduced from the first attempt while 36.1% required a second insufflation. Only 5.55% required a third insufflation to complete the reduction. In cases with unsuccessful pneumatic reduction attempt (18.1%, surgical treatment was required. Surgery ranged from simple reduction to resection with a primary end to end anastomosis. No complications from air enema were recorded. Conclusions: The authors recommend adding pressure release valves to ensure safety by avoiding pressure overshoot during the procedure.

  20. Conversion of Dynamic High Pressures from Air to Water for a Spherical TNT Charge

    Directory of Open Access Journals (Sweden)

    A. K. Sharma

    1996-01-01

    Full Text Available A numerical method has been applied to convert the dynamic high pressures from air-to-water for a spherical TNT charge. Standard equation of scaling law in air for TNT has been utilised to make the necessary conversions. The investigations have been made by taking into consideration the ambient pressure values for the two media. The calculations have been performed under the scaled distances to get better results. Experimental measurements using indigenous blast pressure gauge have been undertaken by detonating spherical charges of TNT under the same scaled distances in water to check the correctness of results and direct application of this method. A fairly close agreement between the theoretically computed and the experimental values of the dynamic high pressures shows the practical utility of this approach in that it enables an estimate of the experimental shock wave pressures, without conducting underwater experiments.

  1. The discharge of fine silica sand in a silo under different ambient air pressures

    Science.gov (United States)

    Hsiau, Shu-San; Liao, Chun-Chung; Lee, Jie-Hsien

    2012-04-01

    Silos are widely used for the industrial scale handling and transportation of powdered and granular materials. The process of discharging powder in a silo involves the flow of both solid particles and an interstitial fluid, usually air. In this study, we experimentally investigate the effects of particle size and ambient pressure on the discharge process in open- and closed-top silos. The discharge rate, pressure drop, and pressure recovery rate are measured and discussed. The results show that the particle size, the diameter of the orifice, and the ambient pressure significantly influence the process of discharge. The effect of air flow is stronger on fine-powdered flow in a closed-top silo. The results indicate that the effects of air flow could be reduced by lowering the ambient pressure. In addition, a normalized critical pressure can be defined beyond which the discharge rate increases dramatically. With reduced ambient pressure, this normalized critical pressure decreases with increasing particle size. Finally, the experimental results are compared with results calculated using the Beverloo equation and Darcy's law.

  2. 42 CFR 84.149 - Type C supplied-air respirator, demand and pressure demand class; minimum requirements.

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Type C supplied-air respirator, demand and pressure... OF RESPIRATORY PROTECTIVE DEVICES Supplied-Air Respirators § 84.149 Type C supplied-air respirator, demand and pressure demand class; minimum requirements. (a) Respirators tested under this section...

  3. Torricelli and the ocean of air: the first measurement of barometric pressure.

    Science.gov (United States)

    West, John B

    2013-03-01

    The recognition of barometric pressure was a critical step in the development of environmental physiology. In 1644, Evangelista Torricelli described the first mercury barometer in a remarkable letter that contained the phrase, "We live submerged at the bottom of an ocean of the element air, which by unquestioned experiments is known to have weight." This extraordinary insight seems to have come right out of the blue. Less than 10 years before, the great Galileo had given an erroneous explanation for the related problem of pumping water from a deep well. Previously, Gasparo Berti had filled a very long lead vertical tube with water and showed that a vacuum formed at the top. However, Torricelli was the first to make a mercury barometer and understand that the mercury was supported by the pressure of the air. Aristotle stated that the air has weight, although this was controversial for some time. Galileo described a method of measuring the weight of the air in detail, but for reasons that are not clear his result was in error by a factor of about two. Torricelli surmised that the pressure of the air might be less on mountains, but the first demonstration of this was by Blaise Pascal. The first air pump was built by Otto von Guericke, and this influenced Robert Boyle to carry out his classical experiments of the physiological effects of reduced barometric pressure. These were turning points in the early history of high-altitude physiology.

  4. Influence of ambient air pressure on impact pressure caused by breaking waves

    NARCIS (Netherlands)

    Moutzouris, C.

    1979-01-01

    Engineers are interested in the dynamics of the interface waterstructure. In case of breaking of water waves on a structure high positive and sometimes negative pressures of very short duration occur. Not only the maxima and minima of the pressures on the structure are important to a designing engin

  5. A handheld low temperature atmospheric pressure air plasma gun for nanomaterial synthesis in liquid phase

    Science.gov (United States)

    Yu, Shuang; Wang, Kaile; Zuo, Shasha; Liu, Jiahui; Zhang, Jue; Fang, Jing

    2015-10-01

    A handheld low temperature atmospheric pressure air plasma gun based on a dielectric barrier structure with hollow electrodes was proposed. The portable plasma gun with an embedded mini air pump was driven by a 12 V direct voltage battery. The air plasma jet generated from the gun could be touched without a common shock hazard. Besides working in air, the plasma gun can also work in water. The diagnostic result of optical emission spectroscopy showed the difference in reactive species of air plasma jet between in air and in water. The plasma gun was excited in 20 ml chloroauric acid aqueous solution with a concentration of 1.214 mM. A significant amount of gold nanoparticles were synthesized after 2 min continuous discharge. The plasma gun with these unique features is applicable in plasma medicine, etching, and s-nthesis of nanomaterials.

  6. A handheld low temperature atmospheric pressure air plasma gun for nanomaterial synthesis in liquid phase

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Shuang; Wang, Kaile; Zuo, Shasha; Liu, Jiahui [Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China); Zhang, Jue, E-mail: zhangjue@pku.edu.cn; Fang, Jing [Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China); College of Engineering, Peking University, Beijing 100871 (China)

    2015-10-15

    A handheld low temperature atmospheric pressure air plasma gun based on a dielectric barrier structure with hollow electrodes was proposed. The portable plasma gun with an embedded mini air pump was driven by a 12 V direct voltage battery. The air plasma jet generated from the gun could be touched without a common shock hazard. Besides working in air, the plasma gun can also work in water. The diagnostic result of optical emission spectroscopy showed the difference in reactive species of air plasma jet between in air and in water. The plasma gun was excited in 20 ml chloroauric acid aqueous solution with a concentration of 1.214 mM. A significant amount of gold nanoparticles were synthesized after 2 min continuous discharge. The plasma gun with these unique features is applicable in plasma medicine, etching, and s-nthesis of nanomaterials.

  7. Numerical simulation of air flow field in high-pressure fan with splitter blades

    Institute of Scientific and Technical Information of China (English)

    Jianfeng LI; Junfu LU; Hai ZHANG; Qing LIU; Guangxi YUE

    2008-01-01

    For a deeper understanding of the flow char-acteristics in the high-pressure centrifugal blower of a fan of Model 9-26 with splitter blades, a three dimensional (3-D) numerical simulation of air flows in the fan was con-ducted with FLUENT software. The standard k-ε tur-bulent model and unstructured grids were used. The computational fluid dynamics (CFD) results showed that the performance of a fan could be improved by adding the splitter blades in the channel among the leaf blades. Under operational conditions, with the presence of splitter blades, the air flow rate of the fan increased about 5% and the total pressure at the outlet of the fan increased about 10% on average. It was also found that the length of the splitter blades affected the air flow and pressure drop. There is an optimal value for the length. The simulation results provide helpful information for improving the fan performance.

  8. Hydraulic Resistance and Liberation of Air in Aviation Kerosene Flow Through Diaphragms at Low Pressure

    Science.gov (United States)

    Kitanin, É. L.; Kitanina, E. É.; Zherebtsov, V. A.; Peganova, M. M.; Stepanov, S. G.; Bondarenko, D. A.; Morisson, D.

    2016-09-01

    This paper presents the results of experimental investigations of the liberation of air in gravity flow of aviation fuel through a pipeline with diaphragms. Experiments were carried out in the pressure range 0.2-1.0 bar and temperature range -20 to +20°C. The TC-1 kerosene was preliminarily saturated with air at atmospheric pressure. The liberation of air after the diaphragms with three ratios of the flow area to the cross-sectional area of the pipeline has been investigated. The results of investigations of the two-phase flow in several experimental pipelines containing one or two diaphragms and other local hydraulic resistances have been generalized. The obtained approximation equations permit calculating the hydraulic resistance of the diaphragm in the two-phase flow and the mass gas content of air after the diaphragm in pipelines of complex geometry.

  9. Atmospheric-pressure air microplasma jets in aqueous media for the inactivation of Pseudomonas fluorescens cells

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xianhui; Yang, Si-ze [Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, School of Physics and Mechanical and Electrical Engineering, Xiamen University, Xiamen, Fujian 361005 (China); Liu, Dongping [Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, School of Physics and Mechanical and Electrical Engineering, Xiamen University, Xiamen, Fujian 361005 (China); School of Physics and Materials Engineering, Dalian Nationalities University, Dalian 116600 (China); Song, Ying [School of Physics and Materials Engineering, Dalian Nationalities University, Dalian 116600 (China); School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116023 (China); Sun, Yue [School of Physics, Changchun University of Science and Technology, Changchun 130022 (China)

    2013-05-15

    The hollow fiber-based cold air microplasma jet array running at atmospheric pressure has been designed to inactivate Pseudomonas fluorescens (P. fluorescens) cells in vitro in aqueous media. The influences of electrode configurations, air flow rate, and applied voltage on the discharge characteristics of the single microplasma jet operating in aqueous media are presented, and the bactericidal efficiency of the hollow fibers-based and large-volume microplasma jet array is reported. Optical emission spectroscopy is utilized to identify excited species during the antibacterial testing of plasma in solutions. These well-aligned and rather stable air microplasma jets containing a variety of short-lived species, such as OH and O radicals and charged particles, are in direct contact with aqueous media and are very effective in killing P. fluorescens cells in aqueous media. This design shows its potential application for atmospheric pressure air plasma inactivation of bacteria cells in aqueous media.

  10. Optimal heat rejection pressure in transcritical carbon dioxide air conditioning and heat pump systems

    DEFF Research Database (Denmark)

    Liao, Shengming; Jakobsen, Arne

    1998-01-01

    Due to the urgent need for environmentally benign refrigerants, the use of the natural substance carbon dioxide in refrigeration systems has gained more and more attention. In systems such as automobile air-conditioners and heat pumps, owing to the relatively high heat rejection temperatures...... dioxide air conditioning or heat pump systems and for intelligent controlling such systems......., the cycles using carbon dioxide as refrigerant will have to operate in the transcritical area. In a transcritical carbon dioxide system, there is an optimal heat rejection pressure that gives a maximum COP. In this paper, it is shown that the value of this optimal heat rejection pressure mainly depends...

  11. Method of measuring the quantity of air liberated in aviation fuel flow at low pipeline pressure

    Science.gov (United States)

    Kitanin, É. L.; Kitanina, E. É.; Zherebtsov, V. A.; Merkulov, O. A.; Peganova, M. M.; Bondarenko, D. A.; Morrison, D.

    2013-09-01

    This paper presents the results of experimental studies of the quantity of air liberated in the flow of aviation fuel in the pipe at a low pressure. Experiments were carried out in the pressure range from 0.2 to 1.0 bar, and the temperature was varied from -20 to +20°C. We propose a method for determining the mass concentration of air dissolved in the fuel measured with the help of a chromatograph. An attempt to use an optical method for measuring the gas content of the flow has shown that it is useful in combination with a chromatographic method needed to calibrate the optical scheme.

  12. Investigation of Ozone Yield of Air Fed Ozonizer by High Pressure Homogeneous Dielectric Barrier Discharge

    Science.gov (United States)

    2013-07-01

    homogeneous dielectric barrier discharge ( DBD ) in dry air by using a simple DBD device. So far, we have tried to apply the homogeneous DBD to an...specific input energy region. In this work, we investigated the effect of gas pressure (from 0.1 MPa to 0.2 MPa) on the ozone yield by homogeneous DBD . The...homogeneous DBD decreased with increasing the gas pressure. 1. Introduction The dielectric barrier discharge ( DBD ) is composed of many filamentary micro

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

    Science.gov (United States)

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

    2014-06-15

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

  14. Theoretical Computation for Non-Equilibrium Air Plasma Electrical Conductivity at Atmospheric Pressure

    Institute of Scientific and Technical Information of China (English)

    HAN Dong; GUO Wen-Kang; XU Ping; LIANG Rong-Qing

    2007-01-01

    @@ Based on the Chapman-Enskog theory, we calculate the electrical conductivity of non-equilibrium air plasma in the two-temperature model. We consider different degrees of non-equilibrium, which is defined by the ratio of electronic temperature to heavy particles temperature. The method of computing the composition of air plasma is demonstrated. After calculating the electrical conductivity from electron temperature 1000 K to 15000K, the present result is compared with Murphy's study [Plasma Chem. Plasma Process 15 (1994) 279] for equilibrium case. All the calculation is completed at atmospheric pressure. The present results may have potential applications in numerical calculation of non-equilibrium air plasma.

  15. LOCA air-injection loads in BWR Mark II pressure suppression containment systems

    Energy Technology Data Exchange (ETDEWEB)

    Kukita, Y.; Shiba, M. (Japan Atomic Energy Research Inst., Tokai, Ibaraki); Namatame, K. (Institute of Nuclear Safety, Tokyo (Japan))

    1984-02-01

    Large-scale blowdown tests were conducted to investigate the thermal-hydrodynamic response of a boiling-water reactor (BWR) Mark II pressure suppression containment system to a postulated loss-of-coolant accident. This paper presents the test results on the early blowdown transients, where air in the drywell is injected into the pressure suppression pool and induces various hydrodynamic loads onto the containment pressure boundary and internal structures. The test data are compared to predictions by analytical models used for the licensing evaluation of the hydrodynamic loads to assess these models.

  16. A coupled surface/subsurface flow model accounting for air entrapment and air pressure counterflow

    DEFF Research Database (Denmark)

    Delfs, Jens Olaf; Wang, Wenqing; Kalbacher, Thomas

    2013-01-01

    wave) shallow flow and two-phase flow in a porous medium. The simultaneous mass transfer between the soil, overland, and atmosphere compartments is achieved by upgrading a fully established leakance concept for overland-soil liquid exchange to an air exchange flux between soil and atmosphere. In a new...

  17. Spontaneous ignition of methane-air mixtures in a wide range of pressures

    NARCIS (Netherlands)

    Zhukov, VP; Sechenov, VA; Starikovskii, AY

    2003-01-01

    The ignition delay in methane-air mixtures (phi = 0.5) within the range of temperatures of 1200-1700 K and pressures of 3-450 atm behind reflected shock waves in a shock tube is measured on the basis of emission of the electron-excited OH radical (transition A(2)Sigma(+) - X(2)Pi) at the wavelength

  18. Spatiotemporally resolved characteristics of a gliding arc discharge in a turbulent air flow at atmospheric pressure

    DEFF Research Database (Denmark)

    Zhu, Jiajian; Gao, Jinlong; Ehn, Andreas

    2017-01-01

    A gliding arc discharge was generated in a turbulent air flow at atmospheric pressure driven by a 35 kHz alternating current (AC) electric power. The spatiotemporally resolved characteristics of the gliding arc discharge, including glow-type discharges, spark-type discharges, short-cutting events...

  19. Sustained diffusive alternating current gliding arc discharge in atmospheric pressure air

    DEFF Research Database (Denmark)

    Zhu, Jiajian; Gao, Jinlong; Li, Zhongshan

    2014-01-01

    Rapid transition from glow discharge to thermal arc has been a common problem in generating stable high-power non-thermal plasmas especially at ambient conditions. A sustained diffusive gliding arc discharge was generated in a large volume in atmospheric pressure air, driven by an alternating...

  20. The Determination of the Percent of Oxygen in Air Using a Gas Pressure Sensor

    Science.gov (United States)

    Gordon, James; Chancey, Katherine

    2005-01-01

    The experiment of determination of the percent of oxygen in air is performed in a general chemistry laboratory in which students compare the results calculated from the pressure measurements obtained with the calculator-based systems to those obtained in a water-measurement method. This experiment allows students to explore a fundamental reaction…

  1. Hydrostatic pressure effect on micro air bubbles deposited on surfaces with a retreating tip.

    Science.gov (United States)

    Huynh, So Hung; Wang, Jingming; Yu, Yang; Ng, Tuck Wah

    2014-06-01

    The effect of hydrostatic pressure on 6 μL air bubbles formed on micropillar structured PDMS and silicone surfaces using a 2 mm diameter stainless steel tip retreated at 1 mm/s was investigated. Dimensional analysis of the tip retraction process showed the experiments to be conducted in the condition where fluid inertial forces are comparable in magnitude with surface tension forces, while viscous forces were lower. Larger bubbles could be left behind on the structured PDMS surface. For hydrostatic pressures in excess of 20 mm H2O (196 Pa), the volume of bubble deposited was found to decrease progressively with pressure increase. The differences in width of the deposited bubbles (in contact with the substrate) were significant at any particular pressure but marginal in height. The attainable height before rupture reduced with pressure increase, thereby accounting for the reducing dispensed volume characteristic. On structured PDMS, the gaseous bridge width (in contact with the substrate) was invariant with tip retraction, while on silicone it was initially reducing before becoming invariant in the lead up to rupture. With silicone, hence, reductions in the contact width and height were both responsible for reduced volumes with pressure increase. Increased hydrostatic pressure was also found to restrict the growth in contact width on silicone during the stage when air was injected in through the tip. The ability to effect bubble size in such a simple manner may already be harnessed in nature and suggests possibilities in technological applications.

  2. Correcting Air-Pressure Data Collected by MEMS Sensors in Smartphones

    Directory of Open Access Journals (Sweden)

    Na-Young Kim

    2015-01-01

    Full Text Available We present a novel correction method for air-pressure data collected by microelectromechanical pressure sensors embedded in Android-based smartphones, in order to render them usable as meteorological data. The first step of the proposed correction method involves removing the mechanically derived outliers existing beyond the physical limits and those existing outside 3σ, as well as a reduction to the mean sea level pressure using the altitude data from digital elevation models. The second correction step involves classifying data by location and linear-regression analysis utilizing the temperature and humidity sensed by the smartphone to reduce correction errors by performing the analysis according to personalized settings. Air-pressure data obtained from smartphones is subject to several influential factors, depending on the users’ external environment. However, once corrected for spatial location, temperature, and humidity and for individual users after a comprehensive quality control, the corrected air-pressure data was highly reliable as an auxiliary resource for automatic weather stations.

  3. Systematic errors in global air-sea CO2 flux caused by temporal averaging of sea-level pressure

    Directory of Open Access Journals (Sweden)

    H. Kettle

    2005-01-01

    Full Text Available Long-term temporal averaging of meteorological data, such as wind speed and air pressure, can cause large errors in air-sea carbon flux estimates. Other researchers have already shown that time averaging of wind speed data creates large errors in flux due to the non-linear dependence of the gas transfer velocity on wind speed (Bates and Merlivat, 2001. However, in general, wind speed is negatively correlated with air pressure, and a given fractional change in the pressure of dry air produces an equivalent fractional change in the atmospheric partial pressure of carbon dioxide (pCO2air. Thus low pressure systems cause a drop in pCO2air, which together with the associated high winds, promotes outgassing/reduces uptake of CO2 from the ocean. Here we quantify the errors in global carbon flux estimates caused by using monthly or climatological pressure data to calculate pCO2air (and thus ignoring the covariance of wind and pressure over the period 1990-1999, using two common parameterisations for gas transfer velocity. Results show that on average, compared with estimates made using 6 hourly pressure data, the global oceanic sink is systematically overestimated by 7% (W92 and 10% (WM99 when monthly mean pressure is used, and 9% (W92 and 12% (WM99 when climatological pressure is used.

  4. Systematic errors in global air-sea CO2 flux caused by temporal averaging of sea-level pressure

    Directory of Open Access Journals (Sweden)

    C. J. Merchant

    2005-01-01

    Full Text Available Long-term temporal averaging of meteorological data, such as wind speed and air pressure, can cause large errors in air-sea carbon flux estimates. Other researchers have already shown that time averaging of wind speed data creates large errors in flux due to the non-linear dependence of the gas transfer velocity on wind speed (Bates and Merlivat, 2001. However, in general, wind speed is negatively correlated with air pressure, and a given fractional change in the pressure of dry air produces an equivalent fractional change in the atmospheric partial pressure of carbon dioxide (pCO2air. Thus low pressure systems cause a drop in pCO2air, which together with the associated high winds, promotes outgassing/reduces uptake of CO2 from the ocean. Here we quantify the errors in global carbon flux estimates caused by using monthly or climatological pressure data to calculate pCO2air (and thus ignoring the covariance of wind and pressure over the period 1990–1999, using two common parameterisations for gas transfer velocity (Wanninkhof, 1992 (W92 and Wanninkhof and McGillis, 1999 (WM99. Results show that on average, compared with estimates made using 6 hourly pressure data, the global oceanic sink is systematically overestimated by 7% (W92 and 10% (WM99 when monthly mean pressure is used, and 9% (W92 and 12% (WM99 when climatological pressure is used.

  5. Acute changes in pulse pressure in relation to constituents of particulate air pollution in elderly persons

    Energy Technology Data Exchange (ETDEWEB)

    Jacobs, Lotte [Occupational and Environmental Medicine, Unit of Lung Toxicology, K.U.Leuven, Leuven (Belgium); Buczynska, Anna [Departement of Chemistry, UA, Wilrijk (Belgium); Walgraeve, Christophe [Research group EnVOC, Department of Sustainable Organic Chemistry and Technology, UGent, Gent (Belgium); Delcloo, Andy [Royal Meteorological Institute, Brussels (Belgium); Potgieter-Vermaak, Sanja [Departement of Chemistry, UA, Wilrijk (Belgium); Molecular Science Institute, School of Chemistry, University of Witwatersrand, Johannesburg (South Africa); Division of Chemistry and Environmental Science, Manchester Metropolitan University, Manchester (United Kingdom); Van Grieken, Rene [Departement of Chemistry, UA, Wilrijk (Belgium); Demeestere, Kristof; Dewulf, Jo; Van Langenhove, Herman [Research group EnVOC, Department of Sustainable Organic Chemistry and Technology, UGent, Gent (Belgium); De Backer, Hugo [Royal Meteorological Institute, Brussels (Belgium); Nemery, Benoit, E-mail: ben.nemery@med.kuleuven.be [Occupational and Environmental Medicine, Unit of Lung Toxicology, K.U.Leuven, Leuven (Belgium); Nawrot, Tim S. [Occupational and Environmental Medicine, Unit of Lung Toxicology, K.U.Leuven, Leuven (Belgium); Centre for Environmental Sciences, Hasselt University, Diepenbeek (Belgium)

    2012-08-15

    An increased pulse pressure (difference between systolic and diastolic blood pressure) suggests aortic stiffening. The objective of this study was to examine the acute effects of both particulate matter (PM) mass and composition on blood pressure, among elderly persons. We carried out a panel study in persons living in elderly homes in Antwerp, Belgium. We recruited 88 non-smoking persons, 70% women with a mean age of 83 years (standard deviation: 5.2). Blood pressure was measured and a blood sample was collected on two time points, which were chosen so that there was an exposure contrast in ambient PM exposure. The elemental content of the collected indoor and outdoor PM{sub 2.5} (particulate matter with an aerodynamic diameter <2.5 {mu}m) mass concentration was measured. Oxygenated polycyclic aromatic hydrocarbons (oxy-PAHs) on outdoor PM{sub 10} (particulate matter with an aerodynamic diameter <10 {mu}m) were measured. Each interquartile range increase of 20.8 {mu}g/m Superscript-Three in 24-h mean outdoor PM{sub 2.5} was associated with an increase in pulse pressure of 4.0 mmHg (95% confidence interval: 1.8-6.2), in persons taking antihypertensive medication (n=57), but not in persons not using antihypertensive medication (n=31) (p for interaction: 0.02). Vanadium, iron and nickel contents of PM{sub 2.5} were significantly associated with systolic blood pressure and pulse pressure, among persons on antihypertensive medication. Similar results were found for indoor concentrations. Of the oxy-PAHs, chrysene-5,6-dione and benzo[a]pyrene-3,6-dione were significantly associated with increases in systolic blood pressure and pulse pressure. In elderly, pulse pressure was positively associated with acute increases in outdoor and indoor air pollution, among persons taking antihypertensive medication. These results might form a mechanistic pathway linking air pollution as a trigger of cardiovascular events.

  6. A Comparative Study of Sound Speed in Air at Room Temperature between a Pressure Sensor and a Sound Sensor

    Science.gov (United States)

    Amrani, D.

    2013-01-01

    This paper deals with the comparison of sound speed measurements in air using two types of sensor that are widely employed in physics and engineering education, namely a pressure sensor and a sound sensor. A computer-based laboratory with pressure and sound sensors was used to carry out measurements of air through a 60 ml syringe. The fast Fourier…

  7. 42 CFR 84.157 - Airflow resistance test; Type C supplied-air respirator, pressure-demand class; minimum...

    Science.gov (United States)

    2010-10-01

    ... respirator, pressure-demand class; minimum requirements. 84.157 Section 84.157 Public Health PUBLIC HEALTH... ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Supplied-Air Respirators § 84.157 Airflow resistance test; Type C supplied-air respirator, pressure-demand class; minimum requirements. (a) The...

  8. Traffic-related air pollution and noise and children's blood pressure : Results from the PIAMA birth cohort study

    NARCIS (Netherlands)

    Bilenko, Natalya; Van Rossem, Lenie; Brunekreef, Bert; Beelen, Rob; Eeftens, Marloes; Hoek, Gerard; Houthuijs, Danny; De Jongste, Johan C.; Van Kempen, Elise; Koppelman, Gerard H.; Meliefste, Kees; Oldenwening, Marieke; Smit, Henriette A.; Wijga, Alet H.; Gehring, Ulrike

    2015-01-01

    Aims: Elevation of a child's blood pressure may cause possible health risks in later life. There is evidence for adverse effects of exposure to air pollution and noise on blood pressure in adults. Little is known about these associations in children. We investigated the associations of air pollution

  9. Traffic-related air pollution and noise and children's blood pressure : Results from the PIAMA birth cohort study

    NARCIS (Netherlands)

    Bilenko, Natalya; van Rossem, Lenie; Brunekreef, Bert; Beelen, Rob; Eeftens, Marloes; Hoek, Gerard; Houthuijs, Danny; de Jongste, Johan C.; van Kempen, Elise; Koppelman, Gerard H.; Meliefste, Kees; Oldenwening, Marieke; Smit, Henriette A.; Wijga, Alet H.; Gehring, Ulrike

    2015-01-01

    Aims Elevation of a child's blood pressure may cause possible health risks in later life. There is evidence for adverse effects of exposure to air pollution and noise on blood pressure in adults. Little is known about these associations in children. We investigated the associations of air pollution

  10. Calibrating airborne measurements of airspeed, pressure and temperature using a Doppler laser air-motion sensor

    Directory of Open Access Journals (Sweden)

    W. A. Cooper

    2014-09-01

    Full Text Available A new laser air-motion sensor measures the true airspeed with a standard uncertainty of less than 0.1 m s−1 and so reduces uncertainty in the measured component of the relative wind along the longitudinal axis of the aircraft to about the same level. The calculated pressure expected from that airspeed at the inlet of a pitot tube then provides a basis for calibrating the measurements of dynamic and static pressure, reducing standard uncertainty in those measurements to less than 0.3 hPa and the precision applicable to steady flight conditions to about 0.1 hPa. These improved measurements of pressure, combined with high-resolution measurements of geometric altitude from the global positioning system, then indicate (via integrations of the hydrostatic equation during climbs and descents that the offset and uncertainty in temperature measurement for one research aircraft are +0.3 ± 0.3 °C. For airspeed, pressure and temperature, these are significant reductions in uncertainty vs. those obtained from calibrations using standard techniques. Finally, it is shown that although the initial calibration of the measured static and dynamic pressures requires a measured temperature, once calibrated these measured pressures and the measurement of airspeed from the new laser air-motion sensor provide a measurement of temperature that does not depend on any other temperature sensor.

  11. Experimental Study on a Standing Wave Thermoacoustic Prime Mover with Air Working Gas at Various Pressures

    Science.gov (United States)

    Setiawan, Ikhsan; Achmadin, Wahyu N.; Murti, Prastowo; Nohtomi, Makoto

    2016-04-01

    Thermoacoustic prime mover is an energy conversion device which converts thermal energy into acoustic work (sound wave). The advantages of this machine are that it can work with air as the working gas and does not produce any exhaust gases, so that it is environmentally friendly. This paper describes an experimental study on a standing wave thermoacoustic prime mover with air as the working gas at various pressures from 0.05 MPa to 0.6 MPa. We found that 0.2 MPa is the optimum pressure which gives the lowest onset temperature difference of 355 °C. This pressure value would be more preferable in harnessing low grade heat sources to power the thermoacoustic prime mover. In addition, we find that the lowest onset temperature difference is obtained when rh /δ k ratio is 2.85, where r h is the hydraulic radius of the stack and δ k is the thermal penetration depth of the gas. Moreover, the pressure amplitude of the sound wave is significantly getting larger from 2.0 kPa to 9.0 kPa as the charged pressure increases from 0.05 MPa up to 0.6 MPa.

  12. Translational, rotational and vibrational temperatures of a gliding arc discharge at atmospheric pressure air

    DEFF Research Database (Denmark)

    Zhu, Jiajian; Gao, Jinlong; Ehn, Andreas

    2014-01-01

    Gliding arc discharges have generally been used to generate non-equilibrium plasma at atmospheric pressure. Temperature distributions of a gliding arc are of great interest both for fundamental plasma research and for practical applications. In the presented studies, translational, rotational...... and vibrational temperatures of a gliding arc generated at atmospheric pressure air are investigated. Translational temperatures (about 1100 K) were measured by laser-induced Rayleigh scattering, and two-dimensional temperature imaging was performed. Rotational and vibrational temperatures (about 3600 K and 6700...

  13. Numerical simulation of premixed Hydrogen/air combustion pressure in a spherical vessel

    Directory of Open Access Journals (Sweden)

    Guo Han-yu

    2016-01-01

    Full Text Available In order to study the development process of hydrogen combustion in a closed vessel, an on-line chemical equilibrium calculator and a numerical simulation method would be used to analysis the combustion pressure and flame front of mixed gas, which based on 20L H2/air explosion experiments in spherical vessel (Crowl and Jo,2009. The results showed that, the turbulent model could reflect the process of combustion, and the error of combustion pressure by simulation is smaller than the Chemical Equilibrium Calculation. The heat loss and incomplete combustion are the main reason to cause the error.

  14. Spatiotemporal relationships between sea level pressure and air temperature in the tropics

    CERN Document Server

    Makarieva, Anastassia M; Nefiodov, Andrei V; Sheil, Douglas; Nobre, Antonio Donato; Li, Bai-Lian Larry

    2014-01-01

    While surface temperature gradients have been highlighted as drivers of low-level atmospheric circulation, the underlying physical mechanisms remain unclear. Lindzen and Nigam (1987) noted that sea level pressure (SLP) gradients are proportional to surface temperature gradients if isobaric height (the height where pressure does not vary in the horizontal plane) is constant; their own model of low-level circulation assumed that isobaric height in the tropics is around 3 km. Recently Bayr and Dommenget (2013) proposed a simple model of temperature-driven air redistribution from which they derived that the isobaric height in the tropics again varies little but occurs higher (at the height of the troposphere). Here investigations show that neither the empirical assumption of Lindzen and Nigam (1987) nor the theoretical derivations of Bayr and Dommenget (2013) are plausible. Observations show that isobaric height is too variable to determine a universal spatial or temporal relationship between local values of air ...

  15. Parameters of a supershort avalanche electron beam generated in atmospheric-pressure air

    Science.gov (United States)

    Tarasenko, V. F.

    2011-05-01

    Conditions under which the number of runaway electrons in atmospheric-pressure air reaches ˜5 × 1010 are determined. Recommendations for creating runaway electron accelerators are given. Methods for measuring the parameters of a supershort avalanche electron beam and X-ray pulses from gas-filled diodes, as well as the discharge current and gap voltage, are described. A technique for determining the instant of runaway electron generation with respect to the voltage pulse is proposed. It is shown that the reduction in the gap voltage and the decrease in the beam current coincide in time. The mechanism of intense electron beam generation in gas-filled diodes is analyzed. It is confirmed experimentally that, in optimal regimes, the number of electrons generated in atmospheric-pressure air with energies T > eU m , where U m is the maximum gap voltage, is relatively small.

  16. Air-pressure tunable depletion width, rectification behavior, and charge conduction in oxide nanotubes.

    Science.gov (United States)

    Alivov, Yahya; Funke, Hans H; Singh, Vivek; Nagpal, Prashant

    2015-02-01

    Metal-oxide nanotubes provide large surface areas and functionalizable surfaces for a variety of optical and electronic applications. Here we report air-tunable rectifying behavior, depletion width modulation, and two-dimensional (2D) charge conduction in hollow titanium-dioxide nanotubes. The metal contact forms a Schottky-diode in the nanotubes, and the rectification factor (on/off ratio) can be varied by more than 3 orders of magnitude (1-2 × 10(3)) as the air pressure is increased from 2 mTorr to atmospheric pressure. This behavior is explained using a change in depletion width of these thin nanotubes by adsorption of water vapor on both surfaces of a hollow nanotube, and the resulting formation of a metal-insulator-semiconductor (MIS) junction, which controls the 2D charge conduction properties in thin oxide nanotubes.

  17. Evaluation of analytical methodology for hydrocarbons in high pressure air and nitrogen systems. [evaluation of methodology

    Science.gov (United States)

    1977-01-01

    Samples of liquid oxygen, high pressure nitrogen, low pressure nitrogen, and missile grade air were studied to determine the hydrocarbon concentrations. Concentration of the samples was achieved by adsorption on a molecular sieve and activated charcoal. The trapped hydrocarbons were then desorbed and transferred to an analytical column in a gas chromatograph. The sensitivity of the method depends on the volume of gas passed through the adsorbent tubes. The value of the method was verified through recoverability and reproducibility studies. The use of this method enables LOX, GN2, and missile grade air systems to be routinely monitored to determine low level increases in specific hydrocarbon concentration that could lead to potentially hazardous conditions.

  18. Characterization of an atmospheric pressure air plasma source for polymer surface modification

    Science.gov (United States)

    Yang, Shujun; Tang, Jiansheng

    2013-10-01

    An atmospheric pressure air plasma source was generated through dielectric barrier discharge (DBD). It was used to modify polyethyleneterephthalate (PET) surfaces with very high throughput. An equivalent circuit model was used to calculate the peak average electron density. The emission spectrum from the plasma was taken and the main peaks in the spectrum were identified. The ozone density in the down plasma region was estimated by Absorption Spectroscopy. NSF and ARC-ODU

  19. Salt Survey Comparison of Pressurized vs Ambient Deck Air Intakes on JEFF (B) Hovercraft

    Science.gov (United States)

    1981-02-02

    10 Vegetation Collected on Lift Fan Screen 21 Figure 11 Paint Stripping in Lift Fan Shows Dirty vs Clean Air 22 APPENDIX FIGURES Figure A-l Nuclepore...terms of the readings on deck and that ingested in No. 6 engine. Although one single reading is insufficient to draw any fir * conclusions, these data, on...salt above 0.14 PPM, correlates with AVCO experimental data (TF-35 engine). 11. The pressurized engine data demonstrated that the effectof leakage

  20. Ionic wind generation by a wire-cylinder-plate corona discharge in air at atmospheric pressure

    OpenAIRE

    Colas, Dorian,; Ferret, Antoine; Pai, David,; Lacoste, Deanna,; Laux, C.

    2010-01-01

    International audience; A wire-cylinder-plate electrode configuration is presented to generate ionic wind with a dc corona discharge in air at atmospheric pressure. The objective of the work is to maximize the power supplied to the flow in order to increase acceleration while avoiding breakdown. Thus, the proposed experimental setup addresses the problem of decoupling the mechanism of ion generation from that of ion acceleration. Using a wire-plate configuration as a reference, we have focuse...

  1. Self-Organized Filaments in Dielectric Barrier Discharge in Air at Atmospheric Pressure

    Institute of Scientific and Technical Information of China (English)

    DONG Li-Fang; LI Xue-Chen; YINZeng-Qian; QIAN Sheng-Fa; OUYANG Ji-Ting; WANG Long

    2001-01-01

    The self-organized filament pattern created by dielectric barrier discharges in air at atmospheric pressure is investigated experimentally. The density and dimension of filament are analysed quantitatively. The experimental results show that the distance between neighbouring filaments decreases with the increased applied voltage or with the decreased width of the gas gap. Also, the diameter of the filament decreases with the increased applied voltages or with the decreased width of the gas gap.

  2. Advancing a smart air cushion system for preventing pressure ulcers using projection Moiré for large deformation measurements

    Science.gov (United States)

    Cheng, Sheng-Lin; Tsai, Tsung-Heng; Lee, Carina Jean-Tien; Hsu, Yu-Hsiang; Lee, Chih-Kung

    2016-03-01

    A pressure ulcer is one of the most important concerns for wheelchair bound patients with spinal cord injuries. A pressure ulcer is a localized injury near the buttocks that bear ischial tuberosity oppression over a long period of time. Due to elevated compression to blood vessels, the surrounding tissues suffer from a lack of oxygen and nutrition. The ulcers eventually lead to skin damage followed by tissue necrosis. The current medical strategy is to minimize the occurrence of pressure ulcers by regularly helping patients change their posture. However, these methods do not always work effectively or well. As a solution to fundamentally prevent pressure ulcers, a smart air cushion system was developed to detect and control pressure actively. The air cushion works by automatically adjusting a patient's sitting posture to effectively relieve the buttock pressure. To analyze the correlation between the dynamic pressure profiles of an air cell with a patient's weight, a projection Moiré system was adopted to measure the deformation of an air cell and its associated stress distribution. Combining a full-field deformation imaging with air pressure measured within an air cell, the patient's weight and the stress distribution can be simultaneously obtained. By integrating a full-field optical metrology with a time varying pressure sensor output coupled with different active air control algorithms for various designs, we can tailor the ratio of the air cells. Our preliminary data suggests that this newly developed smart air cushion has the potential to selectively reduce localized compression on the tissues at the buttocks. Furthermore, it can take a patient's weight which is an additional benefit so that medical personnel can reference it to prescribe the correct drug dosages.

  3. Measurement of the pressure dependence of air fluorescence emission induced by electrons

    CERN Document Server

    Ave, M; Buonomo, B; Busca, N; Cazon, L; Chemerisov, S D; Conde, M E; Crowell, R A; Di Carlo, P; Di Giulio, C; Doubrava, M; Esposito, A; Facal, P; Franchini, F J; Horandel, J; Hrabovsky, M; Iarlori, M; Kasprzyk, T E; Keilhauer, B; Klages, H; Kleifges, M; Kuhlmann, S; Mazzitelli, G; Nozka, L; Obermeier, A; Palatka, M; Petrera, S; Privitera, P; Rídky, J; Rizi, V; Rodríguez, G; Salamida, F; Schovanek, P; Spinka, H; Strazzeri, E; Ulrich, A; Yusof, Z M; Vacek, V; Valente, P; Verzi, V; Waldenmaier, T

    2007-01-01

    The fluorescence detection of ultra high energy (> 10^18 eV) cosmic rays requires a detailed knowledge of the fluorescence light emission from nitrogen molecules, which are excited by the cosmic ray shower particles along their path in the atmosphere. We have made a precise measurement of the fluorescence light spectrum excited by MeV electrons in dry air. We measured the relative intensities of 34 fluorescence bands in the wavelength range from 284 to 429 nm with a high resolution spectrograph. The pressure dependence of the fluorescence spectrum was also measured from a few hPa up to atmospheric pressure. Relative intensities and collisional quenching reference pressures for bands due to transitions from a common upper level were found in agreement with theoretical expectations. The presence of argon in air was found to have a negligible effect on the fluorescence yield. We estimated that the systematic uncertainty on the cosmic ray shower energy due to the pressure dependence of the fluorescence spectrum i...

  4. Evaluation of the Operator Protection Factors Offered by Positive Pressure Air Suits against Airborne Microbiological Challenge

    Directory of Open Access Journals (Sweden)

    Jackie A. Steward

    2012-08-01

    Full Text Available Laboratories throughout the world that perform work with Risk Group 4 Pathogens generally adopt one of two approaches within BSL-4 environments: either the use of positive pressure air-fed suits or using Class III microbiological safety cabinets and isolators for animal work. Within the UK at present, all laboratories working with Risk Group 4 agents adopt the use of Class III microbiological safety cabinet lines and isolators. Operator protection factors for the use of microbiological safety cabinets and isolators are available however; there is limited published data on the operator protection factors afforded by the use of positive pressure suits. This study evaluated the operator protection factors provided by positive pressure air suits against a realistic airborne microbiological challenge. The suits were tested, both intact and with their integrity compromised, on an animated mannequin within a stainless steel exposure chamber. The suits gave operator protection in all tests with an intact suit and with a cut in the leg. When compromised by a cut in the glove, a very small ingress of the challenge was seen as far as the wrist. This is likely to be due to the low airflow in the gloves of the suit. In all cases no microbiological penetration of the respiratory tract was observed. These data provide evidence on which to base safety protocols for use of positive pressure suits within high containment laboratories.

  5. Evaluation of the operator protection factors offered by positive pressure air suits against airborne microbiological challenge.

    Science.gov (United States)

    Steward, Jackie A; Lever, Mark S

    2012-08-01

    Laboratories throughout the world that perform work with Risk Group 4 Pathogens generally adopt one of two approaches within BSL-4 environments: either the use of positive pressure air-fed suits or using Class III microbiological safety cabinets and isolators for animal work. Within the UK at present, all laboratories working with Risk Group 4 agents adopt the use of Class III microbiological safety cabinet lines and isolators. Operator protection factors for the use of microbiological safety cabinets and isolators are available however; there is limited published data on the operator protection factors afforded by the use of positive pressure suits. This study evaluated the operator protection factors provided by positive pressure air suits against a realistic airborne microbiological challenge. The suits were tested, both intact and with their integrity compromised, on an animated mannequin within a stainless steel exposure chamber. The suits gave operator protection in all tests with an intact suit and with a cut in the leg. When compromised by a cut in the glove, a very small ingress of the challenge was seen as far as the wrist. This is likely to be due to the low airflow in the gloves of the suit. In all cases no microbiological penetration of the respiratory tract was observed. These data provide evidence on which to base safety protocols for use of positive pressure suits within high containment laboratories.

  6. Surface Pressure Study of Lipid Aggregates at the Air Water Interface

    Science.gov (United States)

    Shew, Woody; Ploplis Andrews, Anna

    1996-11-01

    Qualitative and quantitative descriptions of the growth of fatty acid aggregates on a water/air interface were made by analyzing surface pressure measurements taken with a Langmuir Balance. High concentrations of palmitic acid, lauric acid, myristic acid, and also phosphatidylethanolamine in solution with chloroform were applied with a syringe to the surface of the Langmuir Balance and surface pressure was monitored as aggregates assembled spontaneously. The aggregation process for palmitic acid was determined to consist of three distinct parts. Exponential curves were fit to the individual regions of the data and growth and decay constants were determined. Surface pressure varied in very complex ways for lauric acid, myristic acid, and phosphatidylethanolamine yet kinetic measurements yield qualitative information about assembly of those aggregates. This research was supported by NSF Grant No. DMR-93-22301.

  7. Emissions measurements for a lean premixed propane/air system at pressures up to 30 atmospheres

    Science.gov (United States)

    Roffe, G.

    1979-01-01

    A series of experiments was conducted in which the emissions of a lean premixed system of propane and air were measured at pressures of 5, 10, 20 and 30 atm in a flametube apparatus. Measurements were made for inlet temperatures between 600K and 1000K and combustor residence times from 1.0 to 3.0 msec. A schematic of the test rig is presented along with graphs showing emissions measurements for nitric oxide, carbon monoxide, and UHC as functions of bustor residence time for various equivalence ratios, entrance temperatures and pressures; typical behavior of emissions as a function of equivalence ratio for a fixed residence time. Correlations of nitric oxide emission index with adiabatic flame temperature for a fixed residence time of 2 msec and pressures from 5 to 30 atm; and adiabatic flame temperature corresponding to CO breakpoint conditions for 2 msec residence time as a function of inlet temperature.

  8. Analysis of an Aircraft Honeycomb Sandwich Panel with Circular Face Sheet/Core Disbond Subjected to Ground-Air Pressurization

    Science.gov (United States)

    Rinker, Martin; Krueger, Ronald; Ratcliffe, James

    2013-01-01

    The ground-air pressurization of lightweight honeycomb sandwich structures caused by alternating pressure differences between the enclosed air within the honeycomb core and the ambient environment is a well-known and controllable loading condition of aerospace structures. However, initial face sheet/core disbonds intensify the face sheet peeling effect of the internal pressure load significantly and can decrease the reliability of the sandwich structure drastically. Within this paper, a numerical parameter study was carried out to investigate the criticality of initial disbonds in honeycomb sandwich structures under ground-air pressurization. A fracture mechanics approach was used to evaluate the loading at the disbond front. In this case, the strain energy release rate was computed via the Virtual Crack Closure Technique. Special attention was paid to the pressure-deformation coupling which can decrease the pressure load within the disbonded sandwich section significantly when the structure is highly deformed.

  9. Calculation of the upper flammability limit of methane/air mixtures at elevated pressures and temperatures.

    Science.gov (United States)

    Van den Schoor, F; Verplaetsen, F; Berghmans, J

    2008-05-30

    Four different numerical methods to calculate the upper flammability limit of methane/air mixtures at initial pressures up to 10 bar and initial temperatures up to 200 degrees C are evaluated by comparison with experimental data. Planar freely propagating flames are calculated with the inclusion of a radiation heat loss term in the energy conservation equation to numerically obtain flammability limits. Three different reaction mechanisms are used in these calculations. At atmospheric pressure, the results of these calculations are satisfactory. At elevated pressures, however, large discrepancies are found. The spherically expanding flame calculations only show a marginal improvement compared with the planar flame calculations. On the other hand, the application of a limiting burning velocity with a pressure dependence Su,lim approximately p(-1/2) is found to predict the pressure dependence of the upper flammability limit very well, whereas the application of a constant limiting flame temperature is found to slightly underestimate the temperature dependence of the upper flammability limit.

  10. Design of a MEMS piezoresistive differential pressure sensor with small thermal hysteresis for air data modules.

    Science.gov (United States)

    Song, Jin Woo; Lee, Jang-Sub; An, Jun-Eon; Park, Chan Gook

    2015-06-01

    The design, fabrication, and evaluation results of a MEMS piezoresistive differential pressure sensor fabricated by the dry etching process are described in this paper. The proposed sensor is designed to have optimal performances in mid-pressure range from 0 psi to 20 psi suitable for a precision air data module. The piezoresistors with a Wheatstone bridge structure are implanted where the thermal effects are minimized subject to sustainment of the sensitivity. The rectangular-shaped silicon diaphragm is adopted and its dimension is analyzed for improving pressure sensitivity and linearity. The bridge resistors are driven by constant current to compensate temperature effects on sensitivity. The designed differential pressure sensor is fabricated by using MEMS dry etching techniques, and the fabricated sensing element is attached and packaged in a Kovar package in consideration of leakage and temperature hysteresis. The implemented sensors are tested and evaluated as well. The evaluation results show the static RSS (root sum square) accuracy including nonlinearity, non-repeatability, and pressure hysteresis before temperature compensation is about 0.09%, and the total error band which includes the RSS accuracy, the thermal hysteresis, and other thermal effects is about 0.11%, which confirm the validity of the proposed design process.

  11. The impact of mass flow and masking on the pressure drop of air filter in heavy-duty diesel engine

    Directory of Open Access Journals (Sweden)

    Gorji-Bandpy Mofid

    2012-04-01

    Full Text Available This paper presents a computational fluid dynamics (CFD calculation approach to predict and evaluate the impact of the mass-flow inlet on the pressure drop of turbocharger`s air filtfer in heavy-duty diesel engine. The numerical computations were carried out using a commercial CFD program whereas the inlet area of the air filter consisted of several holes connected to a channel. After entering through the channel, the air passes among the holes and enters the air filter. The effect of masking holes and hydraulic diameter is studied and investigated on pressure drop. The results indicate that pressure drop increase with decreasing of hydraulic diameter and masking of the holes has considerable affect on the pressure drop.

  12. The impact of mass flow and masking on the pressure drop of air filter in heavy-duty diesel engine

    Science.gov (United States)

    Hoseeinzadeh, Sepideh; Gorji-Bandpy, Mofid

    2012-04-01

    This paper presents a computational fluid dynamics (CFD) calculation approach to predict and evaluate the impact of the mass-flow inlet on the pressure drop of turbocharger`s air filtfer in heavy-duty diesel engine. The numerical computations were carried out using a commercial CFD program whereas the inlet area of the air filter consisted of several holes connected to a channel. After entering through the channel, the air passes among the holes and enters the air filter. The effect of masking holes and hydraulic diameter is studied and investigated on pressure drop. The results indicate that pressure drop increase with decreasing of hydraulic diameter and masking of the holes has considerable affect on the pressure drop.

  13. Heat transfer and pressure distributions on hemisphere-cylinders in methane-air combustion products at Mach 7

    Science.gov (United States)

    Weinstein, I.

    1973-01-01

    Heat-transfer and pressure distributions were measured over the surfaces of three hemisphere-cylinder models tested at a nominal Mach number of 7 in the Langley 8-foot high-temperature structures tunnel which uses methane-air products of combustion as a test medium. The results showed that the heat-transfer and pressure distributions over the surface of the models were in good agreement with experimental data obtained in air and also with theoretical predictions.

  14. Antimicrobial nanoparticle-coated electrostatic air filter with high filtration efficiency and low pressure drop.

    Science.gov (United States)

    Sim, Kyoung Mi; Park, Hyun-Seol; Bae, Gwi-Nam; Jung, Jae Hee

    2015-11-15

    In this study, we demonstrated an antimicrobial nanoparticle-coated electrostatic (ES) air filter. Antimicrobial natural-product Sophora flavescens nanoparticles were produced using an aerosol process, and were continuously deposited onto the surface of air filter media. For the electrostatic activation of the filter medium, a corona discharge electrification system was used before and after antimicrobial treatment of the filter. In the antimicrobial treatment process, the deposition efficiency of S. flavescens nanoparticles on the ES filter was ~12% higher than that on the pristine (Non-ES) filter. In the evaluation of filtration performance using test particles (a nanosized KCl aerosol and submicron-sized Staphylococcus epidermidis bioaerosol), the ES filter showed better filtration efficiency than the Non-ES filter. However, antimicrobial treatment with S. flavescens nanoparticles affected the filtration efficiency of the filter differently depending on the size of the test particles. While the filtration efficiency of the KCl nanoparticles was reduced on the ES filter after the antimicrobial treatment, the filtration efficiency was improved after the recharging process. In summary, we prepared an antimicrobial ES air filter with >99% antimicrobial activity, ~92.5% filtration efficiency (for a 300-nm KCl aerosol), and a ~0.8 mmAq pressure drop (at 13 cm/s). This study provides valuable information for the development of a hybrid air purification system that can serve various functions and be used in an indoor environment.

  15. A Comprehensive Probabilistic Framework to Learn Air Data from Surface Pressure Measurements

    Directory of Open Access Journals (Sweden)

    Ankur Srivastava

    2015-01-01

    Full Text Available Use of probabilistic techniques has been demonstrated to learn air data parameters from surface pressure measurements. Integration of numerical models with wind tunnel data and sequential experiment design of wind tunnel runs has been demonstrated in the calibration of a flush air data sensing anemometer system. Development and implementation of a metamodeling method, Sequential Function Approximation (SFA, are presented which lies at the core of the discussed probabilistic framework. SFA is presented as a tool capable of nonlinear statistical inference, uncertainty reduction by fusion of data with physical models of variable fidelity, and sequential experiment design. This work presents the development and application of these tools in the calibration of FADS for a Runway Assisted Landing Site (RALS control tower. However, the multidisciplinary nature of this work is general in nature and is potentially applicable to a variety of mechanical and aerospace engineering problems.

  16. A study of the glow discharge characteristics of contact electrodes at atmospheric pressure in air

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Wenzheng, E-mail: wzhliu@bjtu.edu.cn; Sun, Guangliang, E-mail: 11121659@bjtu.edu.cn; Li, Chuanhui; Zhang, Rongrong [School of Electrical Engineering, Beijing Jiaotong University, Beijing 100044 (China)

    2014-04-15

    Electric field distributions and discharge properties of rod-rod contact electrodes were studied under the condition of DBD for the steady generation of atmospheric pressure glow discharge plasma (APGD) in air. We found that under the effect of the initial electrons generated in a nanometer-scale gap, the rod-rod cross-contact electrodes yielded APGD plasma in air. Regarding the rod-rod cross-contact electrodes, increasing the working voltage expanded the strong electric field area of the gas gap so that both discharge area and discharge power increased, and the increase in the number of contact points kept the initial discharge voltage unchanged and caused an increase in the plasma discharge area and discharge power. A mesh-like structure of cross-contact electrodes was designed and used to generate more APGD plasma, suggesting high applicability.

  17. BOREAS AFM-5 Level-2 Upper Air Network Standard Pressure Level Data

    Science.gov (United States)

    Barr, Alan; Hrynkiw, Charmaine; Hall, Forrest G. (Editor); Newcomer, Jeffrey A. (Editor); Smith, David E. (Technical Monitor)

    2000-01-01

    The BOREAS AFM-5 team collected and processed data from the numerous radiosonde flights during the project. The goals of the AFM-05 team were to provide large-scale definition of the atmosphere by supplementing the existing AES aerological network, both temporally and spatially. This data set includes basic upper-air parameters interpolated at 0.5 kiloPascal increments of atmospheric pressure from data collected from the network of upper-air stations during the 1993, 1994, and 1996 field campaigns over the entire study region. The data are contained in tabular ASCII files. The data files are available on a CD-ROM (see document number 20010000884) or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

  18. Finite element modelling of high air pressure forming processes for polymer sheets

    Science.gov (United States)

    Jiang, W.-G.; Warby, M. K.; Whiteman, J. R.; Abbott, S.; Shorter, W.; Warwick, P.; Wright, T.; Munro, A.; Munro, B.

    In this paper we describe the mathematical modelling and computational simulation of the high air pressure (HAP) thermoforming process which is used in the creation of thin walled polymeric structures. This involves, using data from material tests, an elastic-plastic constitutive equation valid for large deformations and a constrained deformation in which there is frictional contact between the polymeric sheet and a constraining surface (the mould surface). Despite a number of simplifying assumptions and some uncertainities in the mathematical model the finite element computations presented predict quite well the actual shape and thickness distribution which are found on sample products.

  19. Effect of microwave frequency on plasma formation in air breakdown at atmospheric pressure

    Institute of Scientific and Technical Information of China (English)

    赵朋程; 郭立新; 李慧敏

    2015-01-01

    Microwave breakdown at atmospheric pressure causes the formation of a discrete plasma structure. The one-dimensional fluid model coupling Maxwell equations with plasma fluid equations is used to study the effect of the mi-crowave frequency on the formation of air plasma. Simulation results show that, the filamentary plasma array propagating toward the microwave source is formed at different microwave frequencies. As the microwave frequency decreases, the ratio of the distance between two adjacent plasma filaments to the corresponding wavelength remains almost unchanged (on the order of 1/4), while the plasma front propagates more slowly due to the increase in the formation time of the new plasma filament.

  20. Integrated LTCC Pressure/Flow/Temperature Multisensor for Compressed Air Diagnostics†

    Science.gov (United States)

    Fournier, Yannick; Maeder, Thomas; Boutinard-Rouelle, Grégoire; Barras, Aurélie; Craquelin, Nicolas; Ryser, Peter

    2010-01-01

    We present a multisensor designed for industrial compressed air diagnostics and combining the measurement of pressure, flow, and temperature, integrated with the corresponding signal conditioning electronics in a single low-temperature co-fired ceramic (LTCC) package. The developed sensor may be soldered onto an integrated electro-fluidic platform by using standard surface mount device (SMD) technology, e.g., as a standard electronic component would be on a printed circuit board, obviating the need for both wires and tubes and thus paving the road towards low-cost integrated electro-fluidic systems. Several performance aspects of this device are presented and discussed, together with electronics design issues. PMID:22163518

  1. Integrated LTCC pressure/flow/temperature multisensor for compressed air diagnostics.

    Science.gov (United States)

    Fournier, Yannick; Maeder, Thomas; Boutinard-Rouelle, Grégoire; Barras, Aurélie; Craquelin, Nicolas; Ryser, Peter

    2010-01-01

    We present a multisensor designed for industrial compressed air diagnostics and combining the measurement of pressure, flow, and temperature, integrated with the corresponding signal conditioning electronics in a single low-temperature co-fired ceramic (LTCC) package. The developed sensor may be soldered onto an integrated electro-fluidic platform by using standard surface mount device (SMD) technology, e.g., as a standard electronic component would be on a printed circuit board, obviating the need for both wires and tubes and thus paving the road towards low-cost integrated electro-fluidic systems. Several performance aspects of this device are presented and discussed, together with electronics design issues.

  2. Energy distribution of runaway electrons generated by a nanosecond discharge in atmospheric-pressure air

    Science.gov (United States)

    Tarasenko, V. F.; Baksht, E. Kh.; Burachenko, A. G.; Kostyrya, I. D.; Lomaev, M. I.; Petin, V. K.; Rybka, D. V.; Shlyakhtun, S. V.

    2008-12-01

    The spectra of an ultrashort avalanche electron beam generated by a nanosecond discharge in atmospheric-pressure air were investigated. The temporal characteristics of the beam current pulses, gap voltage, and discharge current in a gas diode were measured with a time resolution of ˜0.1 ns. A simple technique was developed for recovering electron spectra from the curves of beam attenuation by aluminum foils. The effect of the cathode design, electrode gap length, and generator parameters on the electron spectra were studied using seven setups. It is shown that generation of electrons with anomalously high energies requires the use of cathodes with increased curvature radius.

  3. An Explosive Range Model Based on the Gas Composition, Temperature, and Pressure during Air Drilling

    Directory of Open Access Journals (Sweden)

    Xiangyu Fan

    2016-01-01

    Full Text Available Air drilling is low cost and effectively improves the penetration rate and causes minimal damage to liquid-sensitive pay zones. However, there is a potential downhole explosion when combustible gas mixed with drilling fluid reaches the combustible condition. In this paper, based on the underground combustion mechanism, an explosive range calculation model is established. This model couples the state equation and the empirical formula method, which considers the inert gas content, pressure, mixed gas component, and temperature. The result shows that increase of the inert gas content narrows the explosive range, while increase of the gas temperature and pressure improves the explosive range. A case in Chongqing, China, is used to validate the explosive range calculation model.

  4. Investigation of Nanosecond Pulsed Discharge and Its Audio Characteristics in Atmospheric-pressure Air

    Institute of Scientific and Technical Information of China (English)

    REN Chengyan; RAN Huijuan; WANG Jue; WANG Tao; YAN Ping

    2013-01-01

    There was no well-resolved mechanism of audible noise caused by corona discharge on UHV transmission lines.Hence we measured the sound pressure of pulsed discharges between needle-plane electrodes under different discharge conditions in air,for revealing the intrinsic relationship between discharge and its audible noise(AN).The relationship between discharge parameters and audio characteristics was drawn from the analysis of the electric and sound signals obtained in experiments.Experiment results showed that nanosecond pulsed discharges produce the sound pressure with a microsecond pulse lagging behind the discharge pulse in their waveforms.The peak value of the sound pulse decreases and its high frequency component gradually attenuates,when the measuring distance from discharges increases.The sound pulses correlate with the discharge current and voltage significantly,especially the current.The audible noise produced by repetitive pulsed discharge increases with the strength,duration,and pulse repetition rate of discharge.

  5. Bifurcation and Nonlinear Dynamic Analysis of Externally Pressurized Double Air Films Bearing System

    Directory of Open Access Journals (Sweden)

    Cheng-Chi Wang

    2014-01-01

    Full Text Available This paper studies the chaotic and nonlinear dynamic behaviors of a rigid rotor supported by externally pressurized double air films (EPDAF bearing system. A hybrid numerical method combining the differential transformation method and the finite difference method is used to calculate pressure distribution of EPDAF bearing system and bifurcation phenomenon of rotor center orbits. The results obtained for the orbits of the rotor center are in good agreement with those obtained using the traditional finite difference approach. The results presented summarize the changes which take place in the dynamic behavior of the EPDAF bearing system as the rotor mass and bearing number are increased and therefore provide a useful guideline for the bearing system.

  6. Fast step-response settling of micro electrostatic actuators operated at low air pressure using input shaping

    NARCIS (Netherlands)

    Mol, L.; Rocha, L.A.; Cretu, E.; Wolffenbuttel, R.F.

    2009-01-01

    Squeeze-film damping is highly inadequate in low-pressure systems or in systems where air pressure and/or gap dimensions are poorly defined. Input shaping has been used to circumvent the oscillations typically associated with under-damped mass-spring-damper systems and drastically decrease the settl

  7. 磨煤机出口风压及风温的热控安装%Thermal control installation of air pressure and air temperature of pulverizer outlet

    Institute of Scientific and Technical Information of China (English)

    任强

    2011-01-01

    According to the operation ot ZGM-95 type pulverizer produced by Beijing electric power equipment factory great used in northern region, formation and factors of air pressure and air temperature of pulverizer outlet, this paper made induction and analysis, and made technical reformation to the problems influence of the accuracy of air pressure and air temperature of pulverizer outlet, made its accurate measurement, normal operation.%针对北方地区大量使用的北京电力设备总厂生产的ZGM-95型磨煤机在运行过程中,磨出口风压及风温的形成关系和因素,归纳和分析,对影响磨出口风压及风温准确性的问题进行技术改造,使其测量准确,运行正常。

  8. Extreme Air Pollution Conditions Adversely Affect Blood Pressure and Insulin Resistance: The Air Pollution and Cardiometabolic Disease Study.

    Science.gov (United States)

    Brook, Robert D; Sun, Zhichao; Brook, Jeffrey R; Zhao, Xiaoyi; Ruan, Yanping; Yan, Jianhua; Mukherjee, Bhramar; Rao, Xiaoquan; Duan, Fengkui; Sun, Lixian; Liang, Ruijuan; Lian, Hui; Zhang, Shuyang; Fang, Quan; Gu, Dongfeng; Sun, Qinghua; Fan, Zhongjie; Rajagopalan, Sanjay

    2016-01-01

    Mounting evidence supports that fine particulate matter adversely affects cardiometabolic diseases particularly in susceptible individuals; however, health effects induced by the extreme concentrations within megacities in Asia are not well described. We enrolled 65 nonsmoking adults with metabolic syndrome and insulin resistance in the Beijing metropolitan area into a panel study of 4 repeated visits across 4 seasons since 2012. Daily ambient fine particulate matter and personal black carbon levels ranged from 9.0 to 552.5 µg/m(3) and 0.2 to 24.5 µg/m(3), respectively, with extreme levels observed during January 2013. Cumulative fine particulate matter exposure windows across the prior 1 to 7 days were significantly associated with systolic blood pressure elevations ranging from 2.0 (95% confidence interval, 0.3-3.7) to 2.7 (0.6-4.8) mm Hg per SD increase (67.2 µg/m(3)), whereas cumulative black carbon exposure during the previous 2 to 5 days were significantly associated with ranges in elevations in diastolic blood pressure from 1.3 (0.0-2.5) to 1.7 (0.3-3.2) mm Hg per SD increase (3.6 µg/m(3)). Both black carbon and fine particulate matter were significantly associated with worsening insulin resistance (0.18 [0.01-0.36] and 0.22 [0.04-0.39] unit increase per SD increase of personal-level black carbon and 0.18 [0.02-0.34] and 0.22 [0.08-0.36] unit increase per SD increase of ambient fine particulate matter on lag days 4 and 5). These results provide important global public health warnings that air pollution may pose a risk to cardiometabolic health even at the extremely high concentrations faced by billions of people in the developing world today.

  9. Mining seams liable to spontaneous combustion using a system of automatic regulation of air pressure in a ventilation section

    Energy Technology Data Exchange (ETDEWEB)

    Golik, A.S.; Churikov, Yu.V.; Troyan, N.P.

    1980-01-01

    In mining coal seams liable to spontaneous combustion, the possibility of underground fire increases with growing depth of mining, as air depression in lower seams can suck the air from the goaf of upper levels through cracks and fissures in the roof. To preclude this possibility a system of automatic control of air pressure in a ventilated section of a coal mine has been worked out. The system, called SReDA-1, consists in complete isolation of the ventilated section from other workings by conventional means and in exact maintenance of air pressure equal to atmospheric pressure. Technical specifications of ventilating machines used in the SReDA-1 system are given. Scheme of ventilated section using the system is also shown. (In Russian)

  10. A Novel Constant-Pressure Pumped Hydro Combined with Compressed Air Energy Storage System

    Directory of Open Access Journals (Sweden)

    Erren Yao

    2014-12-01

    Full Text Available As intermittent renewable energy is receiving increasing attention, the combination of intermittent renewable energy with large-scale energy storage technology is considered as an important technological approach for the wider application of wind power and solar energy. Pumped hydro combined with compressed air energy storage system (PHCA is one of the energy storage systems that not only integrates the advantages but also overcomes the disadvantages of compressed air energy storage (CAES systems and pumped hydro energy storage systems to solve the problem of energy storage in China’s arid regions. Aiming at the variable working conditions of PHCA system technology, this study proposes a new constant-pressure PHCA. The most significant characteristics of this system were that the water pump and hydroturbine work under stable conditions and this improves the working efficiency of the equipment without incurring an energy loss. In addition, the constant-pressure PHCA system was subjected to energy and exergy analysis, in expectation of exploring an attractive solution for the large-scale storage of existing intermittent renewable energy.

  11. Two-Dimensional Electron Density Measurement of Positive Streamer Discharge in Atmospheric-Pressure Air

    Science.gov (United States)

    Inada, Yuki; Ono, Ryo; Kumada, Akiko; Hidaka, Kunihiko; Maeyama, Mitsuaki

    2016-09-01

    The electron density of streamer discharges propagating in atmospheric-pressure air is crucially important for systematic understanding of the production mechanisms of reactive species utilized in wide ranging applications such as medical treatment, plasma-assisted ignition and combustion, ozone production and environmental pollutant processing. However, electron density measurement during the propagation of the atmospheric-pressure streamers is extremely difficult by using the conventional localized type measurement systems due to the streamer initiation jitters and the irreproducibility in the discharge paths. In order to overcome the difficulties, single-shot two-dimensional electron density measurement was conducted by using a Shack-Hartmann type laser wavefront sensor. The Shack-Hartmann sensor with a temporal resolution of 2 ns was applied to pulsed positive streamer discharges generated in an air gap between pin-to-plate electrodes. The electron density a few ns after the streamer initiation was 7*1021m-3 and uniformly distributed along the streamer channel. The electron density and its distribution profile were compared with a previous study simulating similar streamers, demonstrating good agreement. This work was supported in part by JKA and its promotion funds from KEIRIN RACE. The authors like to thank Mr. Kazuaki Ogura and Mr. Kaiho Aono of The University of Tokyo for their support during this work.

  12. Numerical simulation and experimental validation of a direct current air corona discharge under atmospheric pressure

    Institute of Scientific and Technical Information of China (English)

    Liu Xing-Hua; He Wei; Yang Fan; Wang Hong-Yu; Liao Rui-Jin; Xiao Han-Guang

    2012-01-01

    Air corona discharge is one of the critical problems associated with high-voltage equipment.Investigating the corona mechanism plays a key role in enhancing the electrical insulation performance.An improved self-consistent multi-component two-dimensional plasma hybrid model is presented for the simulation of a direct current atmospheric pressure corona discharge in air.The model is based on plasma hydrodynamic and chemical models,and includes 12 species and 26 reactions.In addition,the photoionization effect is introduced into the model.The simulation on a bar-plate electrode configuration with an inter-electrode gap of 5.0 mm is carried out.The discharge voltage-current characteristics and the current density distribution predicted by the hybrid model agree with the experimental measurements.In addition,the dynamics of volume charged species generation,discharge current waveform,current density distribution at an electrode,charge density,electron temperature,and electric field variations are investigated in detail based on the model.The results indicate that the model can contribute valuable insights into the physics of an air plasma discharge.

  13. Space Charge Transient Kinetic Characteristics in DC Air Corona Discharge at Atmospheric Pressure

    Science.gov (United States)

    Liu, Xinghua; Xian, Richang; Sun, Xuefeng; Wang, Tao; Lv, Xuebin; Chen, Suhong; Yang, Fan

    2014-08-01

    Investigating the corona mechanism plays a key role in enhancing the performance of electrical insulation systems. Numerical simulation offers a better understanding of the physical characteristics of air corona discharges. Using a two-dimensional axisymmetrical kinetics model, into which the photoionization effect is incorporated, the DC air corona discharge at atmosphere pressure is studied. The plasma model is based on a self-consistent, multi-component, and continuum description of the air discharge, which is comprised of 12 species and 22 reactions. The discharge voltage-current characteristic predicted by the model is found to be in quite good agreement with experimental measurements. The behavior of the electronic avalanche progress is also described. O2+ and N2+ are the dominant positive ions, and the values of O- and O2- densities are much smaller than that of the electron. The electron and positive ion have a low-density thin layer near the anode, which is a result of the surface reaction and absorption effect of the electrode. As time progresses, the electric field increases and extends along the cathode surface, whereas the cathode fall shrinks after the corona discharge hits the cathode; thus, in the cathode sheath, the electron temperature increases and the position of its peak approaches to the cathode. The present computational model contributes to the understanding of this physical mechanism, and suggests ways to improve the electrical insulation system.

  14. Numerical Estimation of Incident Wave Parameters Based on the Air Pressure Measurements in Pico OWC Plant

    Energy Technology Data Exchange (ETDEWEB)

    Le Crom, I.; Brito-Melo, A.; Newman, F. Sarmento, A. [Wave Energy Centre, Av. Manuel da Maia, 36, r/c D., Lisbon (Portugal)

    2009-07-01

    The present study aims at assessing the key spectral parameters of the incident wave on a fixed oscillating water column (OWC) device, based on the air pressure measurements inside the chamber and on the numerical hydrodynamic coefficients of the device. The methodology is based on the equation of continuity of the air in the time-domain and linear decomposition of the air flow in the usual terms of radiation and diffraction flows. By applying the Fast Fourier Transform, the time-domain equation is transposed to the respective frequency-domain equation. This methodology was applied to the 400 kW OWC power plant, on the Island of Pico, Azores, which has been monitored since 2005 by the Wave Energy Centre. The numerical hydrodynamic coefficients obtained by the 3D radiation-diffraction boundary element code, AQUADYN-OWC, were used in this study. No measurements of the incident wave in front of the plant are available; therefore the results obtained for a set of records are compared with forecast estimations for the site of Pico plant provided by INETI and also with the measurements of two directional wave rider buoys offshore Pico and Terceira islands. These data are provided by the Centre of Climate, Meteorology and Global Changes and propagated via the SWAN spectral wave model to the zone of interest. Final objective is to improve the control of the Pico plant by assessing its performance for a range of sea states.

  15. Effect of non-thermal air atmospheric pressure plasma jet treatment on gingival wound healing

    Science.gov (United States)

    Lee, Jung-Hwan; Choi, Eun-Ha; Kim, Kwang-Mahn; Kim, Kyoung-Nam

    2016-02-01

    Non-thermal atmospheric pressure plasmas have been applied in the biomedical field for the improvement of various cellular activities. In dentistry, the healing of gingival soft tissue plays an important role in health and aesthetic outcomes. While the biomedical application of plasma has been thoroughly studied in dentistry, a detailed investigation of plasma-mediated human gingival fibroblast (HGF) migration for wound healing and its underlying biological mechanism is still pending. Therefore, the aim of this study is to apply a non-thermal air atmospheric pressure plasma jet (NTAAPPJ) to HGF to measure the migration and to reveal the underlying biological mechanisms involved in the migration. After the characterization of NTAAPPJ by optical emission spectroscopy, the adherent HGF was treated with NTAAPPJ or air with a different flow rate. Cell viability, lipid peroxidation, migration, intracellular reactive oxygen species (ROS), and the expression of migration-related genes (EGFR, PAK1, and MAPK3) were investigated. The level of statistical significance was set at 0.05. NTAAPPJ and air treatment with a flow rate of 250-1000 standard cubic centimetres per minute (sccm) for up to 30 s did not induce significant decreases in cell viability or membrane damage. A significant increase in the migration of mitomycin C-treated HGF was observed after 30 s of NTAAPPJ treatment compared to 30 s air-only treatment, which was induced by high levels of intracellular reactive oxygen species (ROS). An increase in migration-related gene expression and EGFR activation was observed following NTAAPPJ treatment in an air flow rate-dependent manner. This is the first report that NTAAPPJ treatment induces an increase in HGF migration without changing cell viability or causing membrane damage. HGF migration was related to an increase in intracellular ROS, changes in the expression of three of the migration-related genes (EGFR, PAK1, and MAPK1), and EGFR activation. Therefore

  16. Frequency characteristic of response of surface air pressure to changes in flux of cosmic rays

    Science.gov (United States)

    Bogdanov, M. B.

    2014-11-01

    We compare the series of daily-average values of the surface air pressure for De Bilt and Lugano meteorological stations with subtracted linear trends and seasonal harmonics, as well as the series of the flux of galactic cosmic rays (GCRs) at Jungfraujoch station with subtracted moving average over 200 days. Using the method of superposed epochs, we show that the Forbush decreases at both stations are accompanied by increased pressure. Spectral analysis allows us to conclude that the analyzed series are characterized by nonzero coherence in almost the entire frequency range: from 0.02 day-1 day up to the Nyquist frequency of 0.5 day-1. Using changes in the GCR flux as a probing signal, we obtain amplitude-frequency characteristics of the pressure reaction. For both stations, these characteristics are in qualitative agreement with each other and indicate that the atmospheric response can be described by a second-order linear dynamic system that has wide resonance with a maximum at a frequency of 0.15 day-1.

  17. Air Pollution Exposure and Blood Pressure: An Updated Review of the Literature.

    Science.gov (United States)

    Giorgini, Paolo; Di Giosia, Paolo; Grassi, Davide; Rubenfire, Melvyn; Brook, Robert D; Ferri, Claudio

    2016-01-01

    Both high arterial blood pressure (BP) and elevated levels of fine particulate matter (PM2.5) air pollution have been associated with an increased risk for several cardiovascular (CV) diseases, including stroke, heart failure, and myocardial infarction. Given that PM2.5 and high BP are each independently leading risk factors for premature mortality worldwide, a potential relationship between these factors would have tremendous public health repercussions. Therefore, the aim of this review is to summarize recent evidence linking air pollution and BP. Epidemiological findings demonstrate that particulate pollutants cause significant increases in BP parameters in relation to both short and long-term exposures, with robust evidence for exposures to PM2.5. Moreover, recent epidemiological studies suggest a positive association between residence within regions with higher levels of ambient PM and an increased incidence and prevalence of overt hypertension. Studies provide consistent results that elevated concentrations of pollutants increase hospital admissions and/or emergency visits for hypertensive disorders and also support that PM levels increases BP in vulnerable subsets of individuals (pregnant women, high CV risk individuals). In this context, PM-mediated BP elevations may be an important pathway which acts as a potential triggering factor for acute CV events. Mechanistic evidence illustrates plausible pathways by which acute and chronic exposures to air pollutants might disrupt hemodynamic balance favoring vasoconstriction, including autonomic imbalance and augmented release of various pro-oxidative, inflammatory and/or hemodynamically-active mediators. Together these responses may underlie PM-induced BP elevations; however, full details regarding the responsible mechanisms require further studies. As a consequence of the ubiquity of air pollution, even a small effect on raising BP and/or the prevalence of hypertension, i.e. the major risk factor for mortality

  18. Atmospheric pressure resistive barrier air plasma jet induced bacterial inactivation in aqueous environment

    Science.gov (United States)

    Thiyagarajan, Magesh; Sarani, Abdollah; Gonzales, Xavier

    2013-03-01

    An atmospheric pressure resistive barrier air plasma jet is designed to inactivate bacteria in aqueous media in direct and indirect exposure modes of treatment. The resistive barrier plasma jet is designed to operate at both dc and standard 50-60 Hz low frequency ac power input and the ambient air at 50% humidity level was used as the operating gas. The voltage-current characteristics of the plasma jet were analyzed and the operating frequency of the discharge was measured to be 20 kHz and the plasma power was measured to be 26 W. The plasma jet rotational temperatures (Trot) are obtained from the optical emission spectra, from the N2C-B(2+) transitions by matching the experimental spectrum results with the Spectra Air (SPECAIR) simulation spectra. The reactive oxygen and nitrogen species were measured using optical emission spectroscopy and gas analyzers, for direct and indirect treatment modes. The nitric oxides (NO) were observed to be the predominant long lived reactive nitrogen species produced by the plasma. Three different bacteria including Staphylococcus aureus (Gram-positive), Escherichia coli (Gram-negative), and Neisseria meningitidis (Gram-negative) were suspended in an aqueous media and treated by the resistive barrier air plasma jet in direct and indirect exposure modes. The results show that a near complete bacterial inactivation was achieved within 120 s for both direct and indirect plasma treatment of S. aureus and E. coli bacteria. Conversely, a partial inactivation of N. meningitidis was observed by 120 s direct plasma exposure and insignificant inactivation was observed for the indirect plasma exposure treatment. Plasma induced shifts in N. meningitidis gene expression was analyzed using pilC gene expression as a representative gene and the results showed a reduction in the expression of the pilC gene compared to untreated samples suggesting that the observed protection against NO may be regulated by other genes.

  19. Direct measurement of the capillary pressure characteristics of water-air-gas diffusion layer systems for PEM fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Gostick, Jeff T.; Ioannidis, Marios A.; Fowler, Michael W.; Pritzker, Mark D. [Department of Chemical Engineering, University of Waterloo, 200 University Avenue West, Waterloo, ON (Canada)

    2008-10-15

    A method and apparatus for measuring the relationship between air-water capillary pressure and water saturation in PEMFC gas diffusion layers (GDL) is described. Capillary pressure data for water injection and withdrawal from typical GDL materials are obtained, which demonstrate permanent hysteresis between water intrusion and water withdrawal. Capillary pressure, defined as the difference between the water and gas pressures at equilibrium, is positive during water injection and negative during water withdrawal. The results contribute to the understanding of liquid water behavior in GDL materials which is necessary for the development of effective PEMFC water management strategies. (author)

  20. Association between long-term air pollution and increased blood pressure and hypertension in China.

    Science.gov (United States)

    Dong, Guang-Hui; Qian, Zhengmin Min; Xaverius, Pamela K; Trevathan, Edwin; Maalouf, Salwa; Parker, Jamaal; Yang, Laiji; Liu, Miao-Miao; Wang, Da; Ren, Wan-Hui; Ma, Wenjun; Wang, Jing; Zelicoff, Alan; Fu, Qiang; Simckes, Maayan

    2013-03-01

    Several studies have investigated the short-term effects of ambient air pollutants in the development of high blood pressure and hypertension. However, little information exists regarding the health effects of long-term exposure. To investigate the association between residential long-term exposure to air pollution and blood pressure and hypertension, we studied 24 845 Chinese adults in 11 districts of 3 northeastern cities from 2009 to 2010. Three-year average concentration of particles with an aerodynamic diameter ≤10 µm (PM(10)), sulfur dioxide (SO(2)), nitrogen dioxides (NO(2)), and ozone (O(3)) were calculated from monitoring stations in the 11 districts. We used generalized additive models and 2-level logistic regressions models to examine the health effects. The results showed that the odds ratio for hypertension increased by 1.12 (95% confidence interval [CI], 1.08-1.16) per 19 μg/m(3) increase in PM(10), 1.11 (95% CI, 1.04-1.18) per 20 μg/m(3) increase in SO(2), and 1.13 (95% CI, 1.06-1.20) per 22 μg/m(3) increase in O(3). The estimated increases in mean systolic and diastolic blood pressure were 0.87 mm Hg (95% CI, 0.48-1.27) and 0.32 mm Hg (95% CI, 0.08-0.56) per 19 μg/m(3) interquartile increase in PM(10), 0.80 mm Hg (95% CI, 0.46-1.14) and 0.31 mm Hg (95% CI, 0.10-0.51) per 20 μg/m(3) interquartile increase in SO(2), and 0.73 mm Hg (95% CI, 0.35-1.11) and 0.37 mm Hg (95% CI, 0.14-0.61) per 22 μg/m(3) interquartile increase in O(3). These associations were only statistically significant in men. In conclusion, long-term exposure to PM(10), SO(2), and O(3) was associated with increased arterial blood pressure and hypertension in the study population.

  1. Interaction of high-power microwave with air breakdown plasma at low pressure

    Science.gov (United States)

    Zhao, Pengcheng; Guo, Lixin; Shu, Panpan

    2016-09-01

    The high-power microwave breakdown at the low air pressure (about 0.01 atm) is simulated numerically using the one-dimensional model coupling Maxwell's equations with plasma fluid equations. The accuracy of the model is validated by comparing the breakdown prediction with the experimental data. We find that a diffuse plasma with a stationary front profile forms due to the large electron diffusion. Most of the incident wave energy is absorbed and reflected by the plasma when the plasma front achieves a stationary profile. The front propagation velocity remains almost unchanged with time and increases when the incident wave amplitude increases or the incident wave frequency decreases. With the incident wave frequency increasing, the maximum density of the stationary plasma front increases, while the ratio of the reflected wave power to the incident wave power remains almost unchanged. At a higher incident wave amplitude, the maximum density and reflectance become large.

  2. Synthesis of ammonia directly from air and water at ambient temperature and pressure.

    Science.gov (United States)

    Lan, Rong; Irvine, John T S; Tao, Shanwen

    2013-01-01

    The N≡N bond (225 kcal mol⁻¹) in dinitrogen is one of the strongest bonds in chemistry therefore artificial synthesis of ammonia under mild conditions is a significant challenge. Based on current knowledge, only bacteria and some plants can synthesise ammonia from air and water at ambient temperature and pressure. Here, for the first time, we report artificial ammonia synthesis bypassing N₂ separation and H₂ production stages. A maximum ammonia production rate of 1.14 × 10⁻⁵ mol m⁻² s⁻¹ has been achieved when a voltage of 1.6 V was applied. Potentially this can provide an alternative route for the mass production of the basic chemical ammonia under mild conditions. Considering climate change and the depletion of fossil fuels used for synthesis of ammonia by conventional methods, this is a renewable and sustainable chemical synthesis process for future.

  3. Atmospheric pressure air direct current glow discharge ionization source for ion mobility spectrometry.

    Science.gov (United States)

    Dong, Can; Wang, Weiguo; Li, Haiyang

    2008-05-15

    A new atmospheric pressure air direct current glow discharge (DCGD) ionization source has been developed for ion mobility spectrometry (IMS) to overcome the regularity problems associated with the conventional (63)Ni source and the instability of the negative corona discharge. Its general electrical characteristics were experimentally investigated. By equipping it to IMS, a higher sensitivity was obtained compared to that of a (63)Ni source and corona discharge, and a linear dynamic range from 20 ppb to 20 ppm was obtained for m-xylene. Primary investigations showed that alkanes, such as pentane, which are nondetectable or insensitively detectable with (63)Ni-IMS, can be efficiently detected by DCGD-IMS and the detection limit of 10 ppb can be reached. The preliminary results have shown that the new DCGD ionization source has great potential applications in IMS, such as online monitoring of environment pollutants and halogenated compounds.

  4. Instabilities and soot formation in spherically expanding, high pressure, rich, iso-octane-air flames

    Energy Technology Data Exchange (ETDEWEB)

    Lockett, R D [School of Engineering and Mathematical Sciences, City University, Northampton Square, London EC1V OHB (United Kingdom)

    2006-07-15

    Flame instabilities, cellular structures and soot formed in high pressure, rich, spherically expanding iso-octane-air flames have been studied experimentally using high speed Schlieren cinematography, OH fluorescence, Mie scattering and laser induced incandescence. Cellular structures with two wavelength ranges developed on the flame surface. The larger wavelength cellular structure was produced by the Landau-Darrieus hydrodynamic instability, while the short wavelength cellular structure was produced by the thermal-diffusive instability. Large negative curvature in the short wavelength cusps caused local flame quenching and fracture of the flame surface. In rich flames with equivalence ratio {phi} > 1.8, soot was formed in a honeycomb-like structure behind flame cracks associated with the large wavelength cellular structure induced by the hydrodynamic instability. The formation of soot precursors through low temperature pyrolysis was suggested as a suitable mechanism for the initiation of soot formation behind the large wavelength flame cracks.

  5. Cell immobilization on polymer by air atmospheric pressure plasma jet treatment

    Science.gov (United States)

    Lee, Jung-Hwan; Kwon, Jae-Sung; Om, Ji-yeon; Kim, Yong-Hee; Choi, Eun-Ha; Kim, Kwang-Mahn; Kim, Kyoung-Nam

    2014-08-01

    The study of cell immobilization on delicate polymer by an air atmospheric pressure plasma jet (AAPPJ) is required for its medical application. The aim of this study was to evaluate whether AAPPJ treatment induce cell immobilization effect on delicate polymers without significant change of surface roughness by AAPPJ treatment. After surface roughness, dynamic contact angle, and chemical characteristics were investigated, the immobilization effect was evaluated with the mouse fibroblast L929 cell line. Surface roughness change was not observed (P > 0.05) in either delicate dental wax or polystyrene plate (PSP) as advancing and receding contact angles significantly decreased (P < 0.05), thanks to decreased hydrocarbon and formation of oxygen-related functional groups in treated PSP. Adherent L929 cells with elongated morphology were found in treated PSP along with the formation of immobilization markers vinculin and actin cytoskeleton. Increased PTK2 gene expression upregulated these markers on treated PSP.

  6. Characteristics of a Normal Glow Discharge Excited by DC Voltage in Atmospheric Pressure Air

    Science.gov (United States)

    Li, Xuechen; Zhao, Huanhuan; Jia, Pengying

    2013-11-01

    Atmospheric pressure glow discharges were generated in an air gap between a needle cathode and a water anode. Through changing the ballast resistor and gas gap width between the electrodes, it has been found that the discharges are in normal glow regime judged from the current-voltage characteristics and visualization of the discharges. Results indicate that the diameter of the positive column increases with increasing discharge current or increasing gap width. Optical emission spectroscopy is used to calculate the electron temperature and vibrational temperature. Both the electron temperature and the vibrational temperature increases with increasing discharge current or increasing gap width. Spatially resolved measurements show that the maxima of electron temperature and vibrational temperature appeared in the vicinity of the needle cathode.

  7. Integrated LTCC Pressure/Flow/Temperature Multisensor for Compressed Air Diagnostics†

    Directory of Open Access Journals (Sweden)

    Nicolas Craquelin

    2010-12-01

    Full Text Available We present a multisensor designed for industrial compressed air diagnostics and combining the measurement of pressure, flow, and temperature, integrated with the corresponding signal conditioning electronics in a single low-temperature co-fired ceramic (LTCC package. The developed sensor may be soldered onto an integrated electro-fluidic platform by using standard surface mount device (SMD technology, e.g., as a standard electronic component would be on a printed circuit board, obviating the need for both wires and tubes and thus paving the road towards low-cost integrated electro-fluidic systems. Several performance aspects of this device are presented and discussed, together with electronics design issues.

  8. Ozone production in parallel multichannel dielectric barrier discharge from oxygen and air: the influence of gas pressure

    Science.gov (United States)

    Yuan, Dingkun; Wang, Zhihua; Ding, Can; He, Yong; Whiddon, Ronald; Cen, Kefa

    2016-11-01

    This research aims to investigate the influence of gas pressure (0.1 Mpa-0.2 Mpa) on ozone generation in a parallel multichannel dielectric barrier discharge (DBD) reactor with a narrow gap (0.2 mm). In addition to determining ozone concentration and ozone yield characteristics with gas pressure variation, this paper examines the possible reasons leading to the inconsistency with previous reported results. All the experimental results are plotted on the basis of specific input energy (SIE) in order to conduct the comparison within identical power density. By reviewing the experimental results, the possible cause leading to the inconsistency concerning gas pressure dependences of ozone generation was found using different comparison bases. Results show that ozone generation is slightly suppressed with an increase of gas pressure with an initial increase in SIE. The results of the ozone yield show that an increase of gas pressure would have a favorable effect on ozone production efficiency with an SIE larger than 400 J l-1 in oxygen while ozone yield reaches the maximum at 0.14 Mpa with an SIE larger than 150 J l-1 in air. Increasing gas pressure would lead to a higher critical SIE value at which ozone yield firstly decreases with an increase of SIE both in oxygen and air. The results of nitrogen oxide byproducts show that both NO x byproducts emission and the discharge poisoning effect are suppressed by increasing gas pressure in air plasmas.

  9. Soot Surface Oxidation in Laminar Hydrocarbon/Air Diffusion Flames at Atmospheric Pressure. Appendix I

    Science.gov (United States)

    Xu, F.; El-Leathy, A. M.; Kim, C. H.; Faeth, G. M.; Yuan, Z.-G. (Technical Monitor); Urban, D. L. (Technical Monitor); Yuan, Z.-G. (Technical Monitor)

    2003-01-01

    Soot surface oxidation was studied experimentally in laminar hydrocarbon/air diffusion flames at atmospheric pressure. Measurements were carried out along the axes of round fuel jets burning in coflowing dry air considering acetylene-nitrogen, ethylene, propyiene-nitrogen, propane and acetylene-benzene-nitrogen in the fuel stream. Measurements were limited to the initial stages of soot oxidation (carbon consumption less than 70%) where soot oxidation occurs at the surface of primary soot particles. The following properties were measured as a function of distance above the burner exit: soot concentrations by deconvoluted laser extinction, soot temperatures by deconvoluted multiline emission, soot structure by thermophoretic sampling and analysis using Transmission Electron Microscopy (TEM), concentrations of major stable gas species (N2, H2O, H2, O2, CO, CO2, CH4, C2H2, C2H6, C3H6, C3H8, and C6H6) by sampling and gas chromatography, concentrations of some radical species (H, OH, O) by deconvoluted Li/LiOH atomic absorption and flow velocities by laser velocimetry. For present test conditions, it was found that soot surface oxidation rates were not affected by fuel type, that direct rates of soot surface oxidation by O2 estimated from Nagle and Strickland-Constable (1962) were small compared to observed soot surface oxidation rates because soot surface oxidation was completed near the flame sheet where O2 concentrations were less than 3% by volume, and that soot surface oxidation rates were described by the OH soot surface oxidation mechanism with a collision efficiency of 0.14 and an uncertainty (95% confidence) of +/- 0.04 when allowing for direct soot surface oxidation by O2, which is in reasonably good agreement with earlier observations of soot surface oxidation rates in both premixed and diffusion flames at atmospheric pressure.

  10. An air-pressure-free elastomeric valve for integrated nucleic acid analysis by capillary electrophoresis

    Science.gov (United States)

    Jung, Wooseok; Barrett, Matthew; Brooks, Carla; Rivera, Andrew; Birdsell, Dawn N.; Wagner, David M.; Zenhausern, Frederic

    2015-12-01

    We present a new elastomeric valve for integrated nucleic acid analysis by capillary electrophoresis. The valve functions include metering to capture a designated volume of biological sample into a polymerase chain reaction (PCR) chamber, sealing to preserve the sample during PCR cycling, and transfer of the PCR-products and on-chip formamide post-processing for the analysis of DNA fragments by capillary gel electrophoresis. This new valve differs from prior art polydimethylsiloxane (PDMS) valves in that the valve is not actuated externally by air-pressure or vacuum so that it simplifies a DNA analysis system by eliminating the need for an air-pressure or vacuum source, and off-cartridge solenoid valves, control circuit boards and software. Instead, the new valve is actuated by a thermal cycling peltier assembly integrated within the hardware instrument that tightly comes in contact with a microfluidic cartridge for thermal activation during PCR, so that it spontaneously closes the valve without an additional actuator system. The valve has bumps in the designated locations so that it has a self-alignment that does not require precise alignment of a valve actuator. Moreover, the thickness of the new valve is around 600 μm with an additional bump height of 400 μm so that it is easy to handle and very feasible to fabricate by injection molding compared to other PDMS valves whose thicknesses are around 30-100 μm. The new valve provided over 95% of metering performance in filling the fixed volume of the PCR chamber, preserved over 97% of the sample volume during PCR, and showed very comparable capillary electrophoresis peak heights to the benchtop assay tube controls with very consistent transfer volume of the PCR-product and on-chip formamide. The new valve can perform a core function for integrated nucleic acid analysis by capillary electrophoresis.

  11. Rayleigh-Brillouin scattering profiles of air at different temperatures and pressures

    CERN Document Server

    Gu, Ziyu; van de Water, Willem; Ubachs, Wim

    2013-01-01

    Rayleigh Brillouin (RB) scattering profiles for air have been recorded for the temperature range from 255 to 340 K and the pressure range from 640 to 3300 mbar, covering the conditions relevant for the Earth's atmosphere and for planned atmospheric light detection and ranging (LIDAR) missions. The measurements performed at a wavelength of 366.8 nm detect spontaneous RB scattering at a 90 degree scattering angle from a sensitive intracavity setup, delivering scattering profiles at a 1 percent rms noise level or better. The elusive transport coefficient, the bulk viscosity, is effectively derived by a comparing the measurements to the model, yielding an increased trend. The calculated (Tenti S6) line shapes are consistent with experimental data at the level of 2 percent, meeting the requirements for the future RB scattering LIDAR missions in the Earth's atmosphere. However, the systematic 2 percent deviation may imply that the model has a limit to describe the finest details of RB scattering in air. Finally, it...

  12. Localized etching of polymer films using an atmospheric pressure air microplasma jet

    Science.gov (United States)

    Guo, Honglei; Liu, Jingquan; Yang, Bin; Chen, Xiang; Yang, Chunsheng

    2015-01-01

    A direct-write process device based on the atmospheric pressure air microplasma jet (AμPJ) has been developed for the localized etching of polymer films. The plasma was generated by the air discharge ejected out through a tip-nozzle (inner diameter of 100 μm), forming the microplasma jet. The AμPJ was capable of reacting with the polymer surface since it contains a high concentration of oxygen reactive species and thus resulted in the selective removal of polymer films. The experimental results demonstrated that the AμPJ could fabricate different microstructures on a parylene-C film without using any masks or causing any heat damage. The etch rate of parylene-C reached 5.1 μm min-1 and microstructures of different depth and width could also be realized by controlling two process parameters, namely, the etching time and the distance between the nozzle and the substrate. In addition, combining XPS analysis and oxygen-induced chemical etching principles, the potential etching mechanism of parylene-C by the AμPJ was investigated. Aside from the etching of parylene-C, micro-holes on the photoresist and polyimide film were successfully created by the AμPJ. In summary, maskless pattern etching of polymer films could be achieved using this AμPJ.

  13. Effect of airstream velocity on mean drop diameters of water sprays produced by pressure and air atomizing nozzles

    Science.gov (United States)

    Ingebo, R. D.

    1977-01-01

    A scanning radiometer was used to determine the effect of airstream velocity on the mean drop diameter of water sprays produced by pressure atomizing and air atomizing fuel nozzles used in previous combustion studies. Increasing airstream velocity from 23 to 53.4 meters per second reduced the Sauter mean diameter by approximately 50 percent with both types of fuel nozzles. The use of a sonic cup attached to the tip of an air assist nozzle reduced the Sauter mean diameter by approximately 40 percent. Test conditions included airstream velocities of 23 to 53.4 meters per second at 293 K and atmospheric pressure.

  14. Etching of polymers, proteins and bacterial spores by atmospheric pressure DBD plasma in air

    Science.gov (United States)

    Kuzminova, A.; Kretková, T.; Kylián, O.; Hanuš, J.; Khalakhan, I.; Prukner, V.; Doležalová, E.; Šimek, M.; Biederman, H.

    2017-04-01

    Many studies proved that non-equilibrium discharges generated at atmospheric pressure are highly effective for the bio-decontamination of surfaces of various materials. One of the key processes that leads to a desired result is plasma etching and thus the evaluation of etching rates of organic materials is of high importance. However, the comparison of reported results is rather difficult if impossible as different authors use diverse sources of atmospheric plasma that are operated at significantly different operational parameters. Therefore, we report here on the systematic study of the etching of nine different common polymers that mimic the different structures of more complicated biological systems, bovine serum albumin (BSA) selected as the model protein and spores of Bacillus subtilis taken as a representative of highly resistant micro-organisms. The treatment of these materials was performed by means of atmospheric pressure dielectric barrier discharge (DBD) sustained in open air at constant conditions. All tested polymers, BSA and spores, were readily etched by DBD plasma. However, the measured etching rates were found to be dependent on the chemical structure of treated materials, namely on the presence of oxygen in the structure of polymers.

  15. Surface Treatment of Polyethylene Terephthalate Film Using Atmospheric Pressure Glow Discharge in Air

    Institute of Scientific and Technical Information of China (English)

    方志; 邱毓昌; 王辉

    2004-01-01

    Non-thermal plasmas under atmospheric pressure are of great interest in polymer surface processing because of their convenience, effectiveness and low cost. In this paper, the treatment of Polyethylene terephthalate (PET) film surface for improving hydrophilicity using the non-thermal plasma generated by atmospheric pressure glow discharge (APGD) in air is conducted.The discharge characteristics of APGD are shown by measurement of their electrical discharge parameters and observation of light-emission phenomena, and the surface properties of PET before and after the APGD treatment are studied using contact angle measurement, x-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). It is found that the APGD is homogeneous and stable in the whole gas gap, which differs from the commonly filamentary dielectric barrier discharge (DBD). A short time (several seconds) APGD treatment can modify the surface characteristics of PET film markedly and uniformly. After 10 s APGD treatment, the surface oxygen content of PET surface increases to 39%, and the water contact angle decreases to 19°, respectively.

  16. Interaction of Atmospheric-Pressure Air Microplasmas with Amino Acids as Fundamental Processes in Aqueous Solution.

    Directory of Open Access Journals (Sweden)

    Renwu Zhou

    Full Text Available Plasma medicine is a relatively new field that investigates potential applications of cold atmospheric-pressure plasmas in bioengineering, such as for bacterial inactivation and degradation of organic molecules in water. In order to enunciate mechanisms of bacterial inactivation at molecular or atomic levels, we investigated the interaction of atmospheric-pressure air microplasmas with amino acids in aqueous solution by using high-resolution mass spectrometry (HRMS. Results show that the oxidation effect of plasma-induced species on the side chains of the amino acids can be categorized into four types, namely hydroxylation, nitration, dehydrogenation and dimerization. In addition, relative activities of amino acids resulting from plasma treatment come in descending order as follows: sulfur-containing carbon-chain amino acids > aromatic amino acids > five-membered ring amino acids > basic carbon-chain amino acids. Since amino acids are building blocks of proteins vital to the growth and reproduction of bacteria, these results provide an insight into the mechanism of bacterial inactivation by plasma.

  17. Interaction of Atmospheric-Pressure Air Microplasmas with Amino Acids as Fundamental Processes in Aqueous Solution

    Science.gov (United States)

    Zhou, Renwu; Zhou, Rusen; Zhuang, Jinxing; Zong, Zichao; Zhang, Xianhui; Liu, Dongping; Bazaka, Kateryna; Ostrikov, Kostya

    2016-01-01

    Plasma medicine is a relatively new field that investigates potential applications of cold atmospheric-pressure plasmas in bioengineering, such as for bacterial inactivation and degradation of organic molecules in water. In order to enunciate mechanisms of bacterial inactivation at molecular or atomic levels, we investigated the interaction of atmospheric-pressure air microplasmas with amino acids in aqueous solution by using high-resolution mass spectrometry (HRMS). Results show that the oxidation effect of plasma-induced species on the side chains of the amino acids can be categorized into four types, namely hydroxylation, nitration, dehydrogenation and dimerization. In addition, relative activities of amino acids resulting from plasma treatment come in descending order as follows: sulfur-containing carbon-chain amino acids > aromatic amino acids > five-membered ring amino acids > basic carbon-chain amino acids. Since amino acids are building blocks of proteins vital to the growth and reproduction of bacteria, these results provide an insight into the mechanism of bacterial inactivation by plasma. PMID:27183129

  18. Microwave air plasmas in capillaries at low pressure I. Self-consistent modeling

    Science.gov (United States)

    Coche, P.; Guerra, V.; Alves, L. L.

    2016-06-01

    This work presents the self-consistent modeling of micro-plasmas generated in dry air using microwaves (2.45 GHz excitation frequency), within capillaries (model couples the system of rate balance equations for the most relevant neutral and charged species of the plasma to the homogeneous electron Boltzmann equation. The maintenance electric field is self-consistently calculated adopting a transport theory for low to intermediate pressures, taking into account the presence of O- ions in addition to several positive ions, the dominant species being O{}2+ , NO+ and O+ . The low-pressure small-radius conditions considered yield very-intense reduced electric fields (˜600-1500 Td), coherent with species losses controlled by transport and wall recombination, and kinetic mechanisms strongly dependent on electron-impact collisions. The charged-particle transport losses are strongly influenced by the presence of the negative ion, despite its low-density (˜10% of the electron density). For electron densities in the range (1-≤ft. 4\\right)× {{10}12} cm-3, the system exhibits high dissociation degrees for O2 (˜20-70%, depending on the working conditions, in contrast with the  ˜0.1% dissociation obtained for N2), a high concentration of O2(a) (˜1014 cm-3) and NO(X) (5× {{10}14} cm-3) and low ozone production (<{{10}-3}% ).

  19. Diffuse plasma treatment of polyamide 66 fabric in atmospheric pressure air

    Science.gov (United States)

    Li, Lee; Peng, Ming-yang; Teng, Yun; Gao, Guozhen

    2016-01-01

    The polyamide 66 (PA66) fabrics are hard to be colored or glued in industrial production due to the poor hydrophily. Diffuse plasma is a kind of non-thermal plasma generated at atmospheric pressure in air. This paper proposes that large-scale diffuse plasma generated between wire electrodes can be employed for improving the hydrophily of PA66 fabrics. A repetitive nanosecond-pulse diffuse-discharge reactor using a cylindrical wire electrode configuration is presented, which can generate large-scale non-thermal plasmas steadily at atmospheric pressure without any barrier dielectric. Then the reactor is used to treat PA66 fabrics in different discharge conditions. The hydrophilicity property of modified PA66 is measured by wicking test method. The modified PA66 is also analyzed by atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) to prove the surface changes in physical microstructure and chemical functional groups, respectively. What's more, the effects of treatment time and treatment frequency on surface modification are investigated and discussed.

  20. Pilot Study of the Effects of Simulated Turbine Passage Pressure on Juvenile Chinook Salmon Acclimated with Access to Air at Absolute Pressures Greater than Atmospheric

    Energy Technology Data Exchange (ETDEWEB)

    Carlson, Thomas J.; Abernethy, Cary S.

    2005-04-28

    The impacts of pressure on juvenile salmon who pass through the turbines of hydroelectric dams while migrating downstream on the Columbia and Snake rivers has not been well understood, especially as these impacts relate to injury to the fish's swim bladder. The laboratory studies described here were conducted by Pacific Northwest National Laboratory for the US Army Corps of Engineers Portland District at PNNL's fisheries research laboratories in 2004 to investigate the impacts of simulated turbine passage pressure on fish permitted to achieve neutral buoyancy at pressures corresponding to depths at which they are typically observed during downstream migration. Two sizes of juvenile Chinook salmon were tested, 80-100mm and 125-145mm total length. Test fish were acclimated for 22 to 24 hours in hyperbaric chambers at pressures simulating depths of 15, 30, or 60 ft, with access to a large air bubble. High rates of deflated swim bladders and mortality were observed. Our results while in conclusive show that juvenile salmon are capable of drawing additional air into their swimbladder to compensate for the excess mass of implanted telemetry devices. However they may pay a price in terms of increased susceptibility to injury, predation, and death for this additional air.

  1. An Ultrasonic and Air Pressure Sensing System for Detection of Behavior before Getting out of Bed Aided by Fuzzy Theory

    Science.gov (United States)

    Yamaguchi, Hayato; Nakajima, Hiroshi; Taniguchi, Kazuhiko; Kobashi, Syoji; Hata, Yutaka

    This paper proposes a sensing system for a behavior detection system using an ultrasonic oscillosensor and an air pressure sensor. The ultrasonic oscillosensor sensor has a cylindrical tank filled with water. It detects the vibration of the target object from the signal reflected from the water surface. This sensor can detect a biological vibration by setting to the bottom bed frame. The air pressure sensor consists of a polypropylene sheet and an air pressure sensor, and detects the pressure information by setting under the bed's mattress. An increase (decrease) in the load placed on the bed is detected by the increase (decrease) in the pressure of the air held in the tube attached to the sheet. We propose a behavior detection system using both sensors, complementally. The system recognizes three states (nobody in bed, keeping quiet in bed, moving in bed) using both sensors, and we detect the behavior before getting out of bed by recognized these states. Fuzzy logic plays a primary role in the system. As the fundamental experiment, we applied the system to five healthy volunteers, the system successfully recognized three states, and detected the behavior before getting out of bed. As the clinical experiment, we applied the system to four elderly patients with dementia, the system exactly detected the behavior before getting out of the bed with enough time for medical care support.

  2. Do sudden air temperature and pressure changes affect cardiovascular morbidity and mortality?

    Science.gov (United States)

    Plavcová, E.; Davídkovová, H.; Kyselý, J.

    2012-04-01

    Previous studies have shown that sudden changes in weather (usually represented by air temperature and/or pressure) are associated with increases in daily mortality. Little is understood about physiological mechanisms responsible for the impacts of weather changes on mortality, and whether similar patterns appear for morbidity as well. Relatively little is known also about differences in the magnitude of the mortality response in provincial regions and in cities, where the impacts may be exacerbated by air pollution effects and/or heat island. The present study examines the effects of sudden air temperature and pressure changes on morbidity (represented by hospital admissions) and mortality due to cardiovascular diseases in the population of the Czech Republic (approx. 10 million inhabitants) and separately in the city of Prague (1.2 million inhabitants). The events are selected from data covering 1994-2009 using the methodology introduced by Plavcová and Kyselý (2010), and they are compared with the datasets on hospital admissions and daily mortality (both standardized to account for long-term changes and the seasonal and weekly cycles). Relative deviations of morbidity/mortality from the baseline were averaged over the selected events for days D-2 (2 days before a change) up to D+7 (7 days after), and their statistical significance was tested by means of the Monte Carlo method. The study aims at (i) identifying those weather changes associated with increased cardiovascular morbidity/mortality, separately in summer and winter, (ii) comparing the effects of weather changes on morbidity and mortality, (iii) identifying whether urban population of Prague is more/less vulnerable in comparison to the population of the whole Czech Republic, (iv) comparing the effects for different cardiovascular diseases (ischaemic heart diseases, ICD-10 codes I20-I25; cerebrovascular diseases, I60-I69; hypertension, I10; atherosclerosis, I70) and individual population groups (by age

  3. Pulsed positive discharges in air at moderate pressures near a dielectric rod

    Science.gov (United States)

    Dubinova, A.; Trienekens, D.; Ebert, U.; Nijdam, S.; Christen, T.

    2016-10-01

    We study pulsed positive discharges in air in a cylindrically symmetric setup with an electrode needle close (about 1 mm) above the top of a dielectric cylindrical rod of 4 mm in diameter mounted at its bottom on a grounded plate electrode. We present ICCD (intensified charge-coupled device) pictures and evaluations of experiments as well as simulations with a fluid discharge model; the simulations use cylindrical symmetry. In the experiments, there is an initial inception cloud phase, where the cylindrical symmetry is maintained, and later a streamer phase, where it is broken spontaneously. At 75-150 mbar, discharges with cylindrical symmetry are not attracted to the dielectric rod, but move away from it. The dielectric rod plays the sole role of an obstacle that shades (in the context of photoionization) a cone-shaped part of the inception cloud; the cone size is determined by the geometry of the setup. The material properties of the dielectric rod, such as its dielectric permittivity and the efficiency of the photon induced secondary electron emission do not have a noticeable effect. This is due to the abundance of photoionization in air, which supplies a positive discharge with free electrons and allows it to propagate along the electric field lines. Using some simple field calculations, we show that field enhancement due to dielectric polarization does not play a significant role in our geometry as long as the discharge maintains its cylindrical symmetry. The field component towards the rod is insufficiently enhanced to cause the discharge to move towards the rod. Any additional electrons produced by the dielectric surface do not influence this discharge morphology. This interpretation is supported by both experiments and simulations. At higher pressures (400-600 mbar) or for larger gaps between the needle and the dielectric rod, the inception cloud reaches its maximal radius within the gap between needle and rod and destabilizes there. In those cases

  4. Kinetic studies of NO formation in pulsed air-like low-pressure dc plasmas

    Science.gov (United States)

    Hübner, M.; Gortschakow, S.; Guaitella, O.; Marinov, D.; Rousseau, A.; Röpcke, J.; Loffhagen, D.

    2016-06-01

    The kinetics of the formation of NO in pulsed air-like dc plasmas at a pressure of 1.33 mbar and mean currents between 50 and 150 mA of discharge pulses with 5 ms duration has been investigated both experimentally and by self-consistent numerical modelling. Using time-resolved quantum cascade laser absorption spectroscopy, the densities of NO, NO2 and N2O have been measured in synthetic air as well as in air with 0.8% of NO2 and N2O, respectively. The temporal evolution of the NO density shows four distinct phases during the plasma pulse and the early afterglow in the three gas mixtures that were used. In particular, a steep density increase during the ignition phase and after termination of the discharge current pulse has been detected. The NO concentration has been found to reach a constant value of 0.57× {{10}14}~\\text{molecules}~\\text{c}{{\\text{m}}-3} , 1.05× {{10}14}~\\text{molecules}~\\text{c}{{\\text{m}}-3} , and 1.3× {{10}14}~\\text{molecules}~\\text{c}{{\\text{m}}-3} for mean plasma currents of 50 mA, 100 mA and 150 mA, respectively, in the afterglow. The measured densities of NO2 and N2O in the respective mixture decrease exponentially during the plasma pulse and remain almost constant in the afterglow, especially where the admixture of NO2 has a remarkable impact on the NO production during the ignition. The numerical results of the coupled solution of a set of rate equations for the various heavy particles and the time-dependent Boltzmann equation of the electrons agree quite well with the experimental findings for the different air-like plasmas. The main reaction processes have been analysed on the basis of the model calculations and the remaining differences between the experiment and modelling especially during the afterglow are discussed.

  5. Ultrasound enhanced plasma treatment of glass-fibre-reinforced polyester in atmospheric pressure air for adhesion improvement

    DEFF Research Database (Denmark)

    Kusano, Yukihiro; Singh, Shailendra Vikram; Norrman, Kion

    2011-01-01

    A glass-fibre-reinforced polyester (GFRP) plate was treated with dielectric barrier discharge (DBD) at atmospheric pressure in air for adhesion improvement. The effects of ultrasonic irradiation using a high-power gas-jet generator during the treatment were investigated. The optical emission...

  6. Manufacturers of Copper Tube for Central Air Conditioner Use Face Mounting Pressure in the Final Quarter of the Year

    Institute of Scientific and Technical Information of China (English)

    2014-01-01

    <正>This year,the investment growth rate of real estate industry continued to slow down,sold area of commercial housing also dropped significantly,which brought huge pressure to the domestic air conditioning manufactures.In the first half of the year,by relying on high growth in national financial expenditure,along with investment in public infrastructure

  7. Soot Oxidation in Laminar Hydrocarbon/Air Diffusion Flames at Atmospheric Pressure. Appendix D

    Science.gov (United States)

    Xu, F.; El-Leathy, A. M.; Faeth, G. M.

    2000-01-01

    Soot oxidation was studied experimentally in laminar hydrocarbon/air diffusion flames at atmospheric pressure. Measurements were carried out along the axes of round jets burning in coflowing air considering acetylene, ethylene, proplyene and propane as fuels. Measurements were limited to the initial stages of soot oxidation (carbon consumption less than 70%) where soot oxidation mainly occurs at the surface of primary soot particles. The following properties were measured as a function of distance above the burner exit: soot concentrations by deconvoluted laser extinction, soot temperatures by deconvoluted multiline emission, soot structure by thermophoretic sampling and analysis using Transmission Electron Microscopy (TEM), concentrations of stable major gas species (N2, H2O, H2, 02, CO, CO2, CH4, C2H2, C2H4, C2H6, C3H6, and C3H8) by sampling and gas chromatography, concentrations of some radical species (H, OH, O) by the deconvoluted Li/LiOH atomic absorption technique and flow velocities by laser velocimetry. It was found that soot surface oxidation rates are not particularly affected by fuel type for laminar diffusion flames and are described reasonably well by the OH surface oxidation mechanism with a collision efficiency of 0.10, (standard deviation of 0.07) with no significant effect of fuel type in this behavior; these findings are in good agreement with the classical laminar premixed flame measurements of Neoh et al. Finally, direct rates of surface oxidation by O2 were small compared to OH oxidation for present conditions, based on estimated O2 oxidation rates due to Nagle and Strickland-Constable, because soot oxidation was completed near the flame sheet where O2 concentrations were less than 1.2% by volume.

  8. Soot Oxidation in Hydrocarbon/Air Diffusion Flames at Atmospheric Pressure. Appendix K

    Science.gov (United States)

    Xu, F.; El-Leathy, A. M.; Faeth, G. M.; Urban, D. L. (Technical Monitor); Yuan, Z.-G. (Technical Monitor)

    2001-01-01

    Soot oxidation was studied experimentally in laminar hydrocarbon/air diffusion flames at atmospheric pressure. Measurements were carried out along the axes of round jets burning in coflowing air considering acetylene, ethylene, propylene and propane as fuels. Measurements were limited to the initial stages of soot oxidation (carbon consumption less than 70%) where soot oxidation mainly occurs at the surface of primary soot particles. The following properties were measured as a function of distance above the burner exit: soot concentrations by deconvoluted laser extinction, soot temperatures by deconvoluted multiline emission, soot structure by thermophoretic sampling and analysis using Transmission Electron Microscopy (TEM), concentrations of stable major gas species (N2, H2O, H2, O2, CO, CO2, CH4, C2H2,C2H4, C2H6, C3H6, and C3H8) by sampling and gas chromatography, concentrations of some radical species (H, OH, O) by the deconvoluted Li/LiOH atomic absorption technique and flow velocities by laser velocimetry. It was found that soot surface oxidation rates are not particularly affected by fuel type for laminar diffusion flames and are described reasonably well by the OH surface oxidation mechanism with a collision efficiency of 0.10, (standard deviation of 0.07) with no significant effect of fuel type in this behavior; these findings are in good agreement with the classical laminar premixed flame measurements of Neoh et al. Finally, direct rates of surface oxidation by O2 were small compared to OH oxidation for present conditions, based on estimated O2 oxidation rates due to Nagle and Strickland-Constable (1962), because soot oxidation was completed near the flame sheet where O2 concentrations were less than 1.2% by volume.

  9. High pressure air spray assistant power supply control strategies and their effects on diesel engine under transient operations

    Institute of Scientific and Technical Information of China (English)

    HAN Yongqiang; LIU Zhongchang; WANG Zhongshu; ZHU Ruoqun

    2007-01-01

    In order to reduce smoke from direct-injection (DI) turbo-charged and after-cooled (TCA) diesel engines under transient operations,the real-time controlling and measuring system of a high pressure air spray assistant power supply (HPAS) was developed.Effects of HPAS on a DI TCA diesel engine under constant engine speed and increased torque (CSIT) transient operations were studied by using different control strategies.Pre-spray (PS) strategy,which means supplying highly pressurized air into the exhaust manifold two seconds before the accelerating-graph begins to rise and stopping spraying air when the acceleratinggraph stops rising.Two other strategies-full-time-spray(FTS) and middle-time-spray (MTS)-were used to fully exploit HPAS potential.With the FTS and MTS strategies,the HPAS system can remarkably decrease smoke from DI TCA diesel engines under transient operations.

  10. The association of annual air pollution exposure with blood pressure among patients with sleep-disordered breathing.

    Science.gov (United States)

    Liu, Wen-Te; Lee, Kang-Yun; Lee, Hsin-Chien; Chuang, Hsiao-Chi; Wu, Dean; Juang, Jer-Nan; Chuang, Kai-Jen

    2016-02-01

    While sleep-disordered breathing (SDB), high blood pressure (BP) and air pollution exposure have separately been associated with increased risk of cardiopulmonary mortality, the association linking air pollution exposure to BP among patients with sleep-disordered breathing is still unclear. We collected 3762 participants' data from the Taipei Medical University Hospital's Sleep Center and air pollution data from the Taiwan Environmental Protection Administration. Associations of 1-year mean criteria air pollutants [particulate matter with aerodynamic diameters ≤10 μm (PM10), particulate matter with aerodynamic diameters ≤2.5 μm (PM2.5), nitrogen dioxide (NO2) and ozone (O3)] with systolic BP (SBP) and diastolic BP (DBP) were investigated by generalized additive models. After controlling for age, sex, body mass index (BMI), temperature and relative humidity, we observed that increases in air pollution levels were associated with decreased SBP and increased DBP. We also found that patients with apnea-hypopnea index (AHI) ≥30 showed a stronger BP response to increased levels of air pollution exposure than those with AHIpollution exposure on BP were found in overweight participants than in participants with normal BMI. We concluded that annual exposure to air pollution was associated with change of BP among patients with sleep-disordered breathing. The association between annual air pollution exposure and BP could be modified by AHI and BMI.

  11. Study of heat transfer and pressure drop characteristics of air heat exchanger using PCM for free cooling applications

    Directory of Open Access Journals (Sweden)

    Kalaiselvam Sivakumar

    2016-01-01

    Full Text Available Free cooling is the process of storing the cool energy available in the night ambient air and using it during the day. The heat exchanger used in this work is a modular type which is similar to the shell and tube heat exchanger. The shell side is filled with Phase Change Materials (PCM and air flow is through the tubes in the module. The modules of the heat exchanger are arranged one over other with air spacers in between each module. The air space provided in between the module in-creases the retention time of the air for better heat transfer. Transient Computational Fluid Dynamics modeling is carried out for single air passage in a modular heat exchanger. It shows that the PCM phase transition time in the module in which different shape of fins is adopted. The module with rectangular fins has 17.2 % reduction in solidification compared with the plain module. Then steady state numerical analysis is accomplished to the whole module having the fin of high heat transfer, so that pressure drop, flow and thermal characteristics across the module and the air spacers are deter-mined for various air inlet velocities of 0.4 to 1.6 m/s. To validate the computational results, experiments are carried out and the agreement was found to be good.

  12. Pressure Relief, Visco-Elastic Foam with Inflated Air? A Pilot Study in a Dutch Nursing Home

    Directory of Open Access Journals (Sweden)

    Martin Van Leen

    2015-02-01

    Full Text Available Objective: There is still little evidence regarding the type of mattress that is the best for preventing pressure ulcers (PUs. In a Dutch nursing home, a new type of overlay mattress (air inflated visco-elastic foam was tested to analyze the opportunity for replacement of the normally used static air overlay mattress in its three-step PU prevention protocol In this small pilot the outcome measures were: healing of a category one pressure ulcer, new development or deterioration of a category one PU and need for repositioning. Methods: We included 20 nursing home residents with a new category one pressure ulcer, existing for no longer than 48 h following a consecutive sampling technic. All residents were staying for more than 30 days in the nursing home and were lying on a visco-elastic foam mattress without repositioning (step one of the 3-step protocol at the start of the pilot study. They had not suffered from a PU in the month before. The intervention involved use of an air inflated foam overlay instead of a static air overlay (normally step 2 of the 3-step protocol. At the start; the following data were registered: age; gender; main diagnosis and presence of incontinence. Thereafter; all participating residents were checked weekly for PU healing tendency; deterioration of PUs; new PUs and need of repositioning. Only when residents showed still a category one PU after 48 h or deterioration of an existing pressure ulcer or if there was development of a new pressure ulcer, repositioning was put into practice (step 3 of the PU protocol. All residents participated during 8 weeks. Results: Seven residents developed a new pressure ulcer category one and still had a category one pressure ulcer at the end of the study period. One resident developed a pressure ulcer category 2. Fifteen residents needed repositioning from one week after start of the study until the end of the study. Conclusions: Overall 40% of the residents developed a pressure ulcer

  13. Nanosecond Repetitively Pulsed Discharges in Air at Atmospheric Pressure -- Experiment and Theory of Regime Transitions

    Science.gov (United States)

    Pai, David; Lacoste, Deanna; Laux, Christophe

    2009-10-01

    In atmospheric pressure air preheated from 300 to 1000 K, the Nanosecond Repetitively Pulsed (NRP) method has been used to generate corona, glow, and spark discharges. Experiments have been performed to determine the parameter space (applied voltage, pulse repetition frequency, ambient gas temperature, and inter-electrode gap distance) of each discharge regime. Notably, there is a minimum gap distance for the existence of the glow regime that increases with decreasing gas temperature. A theory is developed to describe the Corona-to-Glow (C-G) and Glow-to-Spark (G-S) transitions for NRP discharges. The C-G transition is shown to depend on the Avalanche-to-Streamer Transition (AST) as well as the electric field strength in the positive column. The G-S transition is due to the thermal ionization instability. The minimum gap distance for the existence of the glow regime can be understood by considering that the applied voltage of the AST must be lower than that of the thermal ionization instability. This is a previously unknown criterion for generating glow discharges, as it does not correspond to the Paschen minimum or to the Meek-Raether criterion.

  14. Preliminary Investigation of a Dielectric Barrier Discharge Lamp in Open Air at Atmospheric Pressure

    Institute of Scientific and Technical Information of China (English)

    LIU Feng; WANG Wei-Wei; CHANG Xi-Jiang; LIANG Rong-Qing

    2011-01-01

    @@ A dielectric barrier discharge (DBD) lamp is investigated by using sinusoidal power with a 10 kHz frequency in open air at atmospheric pressure.With increasing applied voltages, the different discharge phenomena appear.At relatively low voltages, the discharge states are general stochastic filamentary discharges with weak light.However, at relatively high voltages, the walls of quartz tubes are heated sharply by plasma, and then the dazzling light is emitted very quickly to form the DBD Lamp, corresponding to the low maintaining voltage that is lower than the ignited voltage.The discharge state or mode of the DBD lamp that corresponds to the glow discharge is deduced according to the wave form of the circuit current, which is evidently different from the filamentary discharges.Under these conditions, the spectrum of the DBD lamp is continuous in the range 400-932nm, which is scanned in the range 300-932nm.It is also shown that there is another discharge state or mode that is different from the traditional filamentary discharges.Therefore, it is concluded that the discharge state or mode of the DBD lamp is a glow discharge.

  15. High pressure air jet in the endoscopic preparation room: risk of noise exposure on occupational health.

    Science.gov (United States)

    Chiu, King-Wah; Lu, Lung-Sheng; Wu, Cheng-Kun

    2015-01-01

    After high-level disinfection of gastrointestinal endoscopes, they are hung to dry in order to prevent residual water droplets impact on patient health. To allow for quick drying and clinical reuse, some endoscopic units use a high pressure air jet (HPAJ) to remove the water droplets on the endoscopes. The purpose of this study was to evaluate the excessive noise exposure with the use of HPAJ in endoscopic preparation room and to investigate the risk to occupational health. Noise assessment was taken during 7 automatic endoscopic reprocessors (AERs) and combined with/without HPAJ use over an 8-hour time-weighted average (TWA). Analytical procedures of the NIOSH and the ISO for noise-induced hearing loss were estimated to develop analytic models. The peak of the noise spectrum of combined HPAJ and 7 AERs was significantly higher than that of the 7 AERs alone (108.3 ± 1.36 versus 69.3 ± 3.93 dBA, P risk of hearing loss (HL > 2.5 dB) was 2.15% at 90 dBA, 11.6% at 95 dBA, and 51.3% at 100 dBA. The odds ratio was 49.1 (95% CI: 11.9 to 203.6). The noise generated by the HPAJ to work over TWA seriously affected the occupational health and safety of those working in an endoscopic preparation room.

  16. Atmospheric pressure He-air plasma jet: Breakdown process and propagation phenomenon

    Directory of Open Access Journals (Sweden)

    Asma Begum

    2013-06-01

    Full Text Available In this paper He-discharge (plasma jet/bullet in atmospheric pressure air and its progression phenomenon has been studied experimentally using ICCD camera, optical emission spectroscopy (OES and calibrated dielectric probe measurements. The repetitive nanosecond pulse has applied to a plasma pencil to generate discharge in the helium gas channel. The discharge propagation speed was measured from the ICCD images. The axial electric field distribution in the plasma jet is inferred from the optical emission spectroscopic data and from the probe measurement. The correlation between the jet velocities, jet length with the pulse duration is established. It shows that the plasma jet is not isolated from the input voltage along its propagation path. The discharge propagation speed, the electron density and the local and average electric field distribution along the plasma jet axis predicted from the experimental results are in good agreement with the data predicted by numerical simulation of the streamer propagation presented in different literatures. The ionization phenomenon of the discharge predicts the key ionization parameters, such as speed, peak electric field in the front, and electron density. The maximum local electric field measured by OES is 95 kV/cm at 1.3 cm of the jet axis, and average EF measured by probe is 24 kV/cm at the same place of the jet. The average and local electron density estimated are in the order of 1011 cm-3 and it reaches to the maximum of 1012 cm-3.

  17. Auto-ignition of lubricating oil working at high pressures in a compressor for an air conditioner

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Chul Jin; Choi, Hyo Hyun [Department of Mechanical Engineering, Sejong University, Seoul 143-747 (Korea, Republic of); Sohn, Chae Hoon, E-mail: chsohn@sejong.ac.kr [Department of Mechanical Engineering, Sejong University, Seoul 143-747 (Korea, Republic of)

    2011-01-15

    Auto-ignition of lubricating oil working in a compressor for an air conditioner is studied experimentally. The adopted lubricating oil is an unknown mixture with multi-components and known to have flash point temperature of 170 deg. C. First, its auto-ignition temperature is measured 365 deg. C at atmospheric pressure. The lubricating oil works under high-pressure condition up to 30 atm and it is heated and cooled down repeatedly. Accordingly, auto-ignition temperatures or flammable limits of lubricating oil are required at high pressures with respect to fire safety. Because there is not a standard test method for the purpose, a new ignition-test method is proposed in this study and thereby, auto-ignition temperatures are measured over the pressure range below 30 atm. The measured temperatures range from 215 deg. C to 255 deg. C and they strongly depend on pressure of gas mixture consisting of oil vapor, nitrogen, and oxygen. They are close to flash point temperature and the lubricating oil can be hazardous when it works for high-pressure operating condition and abundant air flows into a compressor.

  18. Full scale measurements of pressure equalization on air permeable facade elements

    NARCIS (Netherlands)

    Bentum, C.A. van; Geurts, C.P.W.

    2015-01-01

    Wind-induced pressure differences over rain screens are determined by the external pressures and the pressures inside the cavity. Minimizing this pressure difference decreases the risk of water leakage and also helps to minimize the local loads on the façade elements. Current rules to determine the

  19. Personal black carbon exposure influences ambulatory blood pressure: air pollution and cardiometabolic disease (AIRCMD-China) study.

    Science.gov (United States)

    Zhao, Xiaoyi; Sun, Zhichao; Ruan, Yanping; Yan, Jianhua; Mukherjee, Bhramar; Yang, Fumo; Duan, Fengkui; Sun, Lixian; Liang, Ruijuan; Lian, Hui; Zhang, Shuyang; Fang, Quan; Gu, Dongfeng; Brook, Jeffrey R; Sun, Qinghua; Brook, Robert D; Rajagopalan, Sanjay; Fan, Zhongjie

    2014-04-01

    Few prospective studies have assessed the blood pressure effect of extremely high air pollution encountered in Asia's megacities. The objective of this study was to evaluate the association between combustion-related air pollution with ambulatory blood pressure and autonomic function. During February to July 2012, personal black carbon was determined for 5 consecutive days using microaethalometers in patients with metabolic syndrome in Beijing, China. Simultaneous ambient fine particulate matter concentration was obtained from the Beijing Municipal Environmental Monitoring Center and the US Embassy. Twenty-four-hour ambulatory blood pressure and heart rate variability were measured from day 4. Arterial stiffness and endothelial function were obtained at the end of day 5. For statistical analysis, we used generalized additive mixed models for repeated outcomes and generalized linear models for single/summary outcomes. Mean (SD) of personal black carbon and fine particulate matter during 24 hours was 4.66 (2.89) and 64.2 (36.9) μg/m(3). Exposure to high levels of black carbon in the preceding hours was associated significantly with adverse cardiovascular responses. A unit increase in personal black carbon during the previous 10 hours was associated with an increase in systolic blood pressure of 0.53 mm Hg and diastolic blood pressure of 0.37 mm Hg (95% confidence interval, 0.17-0.89 and 0.10-0.65 mm Hg, respectively), a percentage change in low frequency to high frequency ratio of 5.11 and mean interbeat interval of -0.06 (95% confidence interval, 0.62-9.60 and -0.11 to -0.01, respectively). These findings highlight the public health effect of air pollution and the importance of reducing air pollution.

  20. Microwave air plasmas in capillaries at low pressure II. Experimental investigation

    Science.gov (United States)

    Stancu, G. D.; Leroy, O.; Coche, P.; Gadonna, K.; Guerra, V.; Minea, T.; Alves, L. L.

    2016-11-01

    This work presents an experimental study of microwave (2.45 GHz excitation frequency) micro-plasmas, generated in dry air (N2 80%: O2 20%) within a small radius silica capillary (345 µm inner radius) at low pressure (300 Pa) and low powers (80-130 W). Experimental diagnostics are performed using optical emission spectroscopy calibrated in absolute intensity. Axial-resolved measurements (50 µm spatial resolution) of atomic transitions N(3p4S)  →  N(3s4P) O(3p5P)  →  O(3s5S) and molecular transitions N2(C,v‧)  →  N2(B,v″) \\text{N}2+ (B,v‧)  →  \\text{N}2+ (X,v″) allow us to obtain, as a function of the coupled power, the absolute densities of N(3p4S), O(3p5P), N2(C), N2(B) and \\text{N}2+ (B), as well as the gas (rotational) temperature (700-1000 K), the vibrational temperature of N2(C,v) (7000-10 000 K) and the excitation temperatures of N2(C) and N2(B) (11 000 K). The analysis of the H β line-width gives an upper limiting value of 1013 cm-3 for the electron density; its axial variation (4  ×  1011-6  ×  1012 cm-3) being estimated by solving the wave electrodynamics equations for the present geometry, plasma length and electron-neutral collision frequency. The experimental results were compared with the results from a 0D model, presented in companion paper I [1], which couples the system of rate balance equations for the dominant neutral and charged plasma species to the homogeneous two-term electron Boltzmann equation, taking the measured gas temperature and the estimated electron density as input parameters. Good qualitative agreement is found between the measurements and calculations of the local species densities for various powers and axial positions. The dissociation degree of oxygen is found above 10%. Moreover, both the measurements and calculations show evidence of the non-equilibrium behavior of low-temperature plasmas, with vibrational and excitation temperatures at least

  1. Spatiotemporally resolved characteristics of a gliding arc discharge in a turbulent air flow at atmospheric pressure

    Science.gov (United States)

    Zhu, Jiajian; Gao, Jinlong; Ehn, Andreas; Aldén, Marcus; Larsson, Anders; Kusano, Yukihiro; Li, Zhongshan

    2017-01-01

    A gliding arc discharge was generated in a turbulent air flow at atmospheric pressure driven by a 35 kHz alternating current (AC) electric power. The spatiotemporally resolved characteristics of the gliding arc discharge, including glow-type discharges, spark-type discharges, short-cutting events and transitions among the different types of discharges, were investigated using simultaneously optical and electrical diagnostics. The glow-type discharge shows sinusoidal-like voltage and current waveforms with a peak current of hundreds of milliamperes. The frequency of the emission intensity variation of the glow-type discharge is the same as that of the electronic power dissipated in the plasma column. The glow-type discharge can transfer into a spark discharge characterized by a sharp peak current of several amperes and a sudden increase of the brightness in the plasma column. Transitions can also be found to take place from spark-type discharges to glow-type discharges. Short-cutting events were often observed as the intermediate states formed during the spark-glow transition. Three different types of short-cutting events have been observed to generate new current paths between two plasma channel segments, and between two electrodes, as well as between the channel segment and the electrodes, respectively. The short-cut upper part of the plasma column that was found to have no current passing through can be detected several hundreds of microseconds after the short-cutting event. The voltage recovery rate, the period of AC voltage-driving signal, the flow rates and the rated input powers were found to play an important role in affecting the transitions among the different types of discharges.

  2. Liquid Steel at Low Pressure: Experimental Investigation of a Downward Water Air Flow

    Science.gov (United States)

    Thumfart, Maria

    2016-07-01

    In the continuous casting of steel controlling the steel flow rate to the mould is critical because a well-defined flow field at the mould level is essential for a good quality of the cast product. The stopper rod is a commonly used device to control this flow rate. Agglomeration of solid material near the stopper rod can lead to a reduced cross section and thus to a decreased casting speed or even total blockage (“clogging”). The mechanisms causing clogging are still not fully understood. Single phase considerations of the flow in the region of the stopper rod result in a low or even negative pressure at the smallest cross section. This can cause degassing of dissolved gases from the melt, evaporation of alloys and entrainment of air through the porous refractory material. It can be shown that the degassing process in liquid steel is taking place mainly at the stopper rod tip and its surrounding. The steel flow around the stopper rod tip is highly turbulent. In addition refractory material has a low wettability to liquid steel. So the first step to understand the flow situation and transport phenomena which occur near the stopper is to understand the behaviour of this two phase (steel, gas) flow. To simulate the flow situation near the stopper rod tip, water experiments are conducted using a convergent divergent nozzle with three different wall materials and three different contact angles respectively. These experiments show the high impact of the wettability of the wall material on the actual flow structure at a constant gas flow rate.

  3. Soot Formation in Laminar Premixed Ethylene/Air Flames at Atmospheric Pressure. Appendix G

    Science.gov (United States)

    Xu, F.; Sunderland, P. B.; Faeth, G. M.; Urban, D. L. (Technical Monitor)

    2001-01-01

    Soot formation was studied within laminar premixed ethylene/air flames (C/O ratios of 0.78-0.98) stabilized on a flat-flame burner operating at atmospheric pressure. Measurements included soot volume fractions by both laser extinction and gravimetric methods, temperatures by multiline emission, soot structure by thermophoretic sampling and transmission electron microscopy, major gas species concentrations by sampling and gas chromatography, concentrations of condensable hydrocarbons by gravimetric sampling. and velocities by laser velocimetry. These data were used to find soot surface growth rates and primary soot particle nucleation rates along the axes of the flames. Present measurements of soot surface growth rates were correlated successfully by predictions based on typical hydrogen-abstraction/carbon-addition (HACA) mechanisms of Frenklach and co-workers and Colket and Hall. These results suavest that reduced soot surface growth rates with increasing residence time seen in the present and other similar flames were mainly caused by reduced rates of surface activation due to reduced H atom concentrations as temperatures decrease as a result of radiative heat losses. Primary soot particle nucleation rates exhibited variations with temperature and acetylene concentrations that were similar to recent observations for diffusion flames; however, nucleation rates in the premixed flames were significantly lower than in, the diffusion flames for reasons that still must be explained. Finally, predictions of yields of major gas species based on mechanisms from both Frenklach and co-workers and Leung and Lindstedt were in good agreement with present measurements and suggest that H atom concentrations (relevant to HACA mechanisms) approximate estimates based on local thermodynamic equilibrium in the present flames.

  4. Soot Formation in Laminar Acetylene/Air Diffusion Flames at Atmospheric Pressure. Appendix J

    Science.gov (United States)

    Xu, F.; Faeth, G. M.; Urban, D. L. (Technical Monitor); Yuan, Z.-G. (Technical Monitor)

    2001-01-01

    The flame structure and soot-formation (soot nucleation and growth) properties of axisymmetric laminar coflowing jet diffusion flames were studied experimentally. Test conditions involved acetylene-nitrogen jets burning in coflowing air at atmospheric pressure. Measurements were limited to the axes of the flames and included soot concentrations, soot temperatures, soot structure, major gas species concentrations, radical species (H, OH, and O) concentrations, and gas velocities. The results show that as distance increases along the axes of the flames, detectable soot formation begins when significant H concentrations are present, and ends when acetylene concentrations become small. Species potentially associated with soot oxidation--O2, CO2, H2O, O, and OH-are present throughout the soot-formation region so that soot formation and oxidation proceed at the same time. Strong rates of soot growth compared to soot nucleation early in the soot-formation process, combined with increased rates of soot nucleation and oxidation as soot formation proceeds, causes primary soot particle diameters to reach a maximum relatively early in the soot-formation process. Aggregation of primary soot particles proceeds, however, until the final stages of soot oxidation. Present measurements of soot growth (corrected for soot oxidation) in laminar diffusion flames were consistent with earlier measurements of soot growth in laminar premixed flames and exhibited encouraging agreement with existing hydrogen-abstraction/carbon-addition (HACA) soot growth mechanisms in the literature that were developed based on measurements within laminar premixed flames. Measured primary soot particle nucleation rates in the present laminar diffusion flames also were consistent with corresponding rates measured in laminar premixed flames and yielded a crude correlation in terms of acetylene and H concentrations and the temperature.

  5. Soot Formation in Laminar Acetylene/Air Diffusion Flames at Atmospheric Pressure. Appendix H

    Science.gov (United States)

    Xu, F.; Faeth, G. M.; Yuan, Z.-G. (Technical Monitor); Urban, D. L. (Technical Monitor); Yuan, Z.-G. (Technical Monitor)

    2001-01-01

    The flame structure and soot-formation (soot nucleation and growth) properties of axisymmetric laminar coflowing jet diffusion flames were studied experimentally. Test conditions involved acetylene-nitrogen jets burning in coflowing air at atmospheric pressure. Measurements were limited to the axes of the flames and included soot concentrations, soot temperatures, soot structure, major gas species concentrations, radical species (H, OH, and O) concentrations, and gas velocities. The results show that as distance increases along the axes of the flames, detectable soot formation begins when significant H concentrations are present, and ends when acetylene concentrations become small. Species potentially associated with soot oxidation-O2, CO2, H2O, O, and OH-are present throughout the soot-formation region so that soot formation and oxidation proceed at the same time. Strong rates of soot growth compared to soot nucleation early in the soot-formation process, combined with increased rates of soot nucleation and oxidation as soot formation proceeds, causes primary soot particle diameters to reach a maximum relatively early in the soot-formation process. Aggregation of primary soot particles proceeds, however, until the final stages of soot oxidation. Present measurements of soot growth (corrected for soot oxidation) in laminar diffusion flames were consistent with earlier measurements of soot growth in laminar premixed flames and exhibited encouraging agreement with existing hydrogen-abstraction/carbon-addition (HACA) soot growth mechanisms in the literature that were developed based on measurements within laminar premixed flames. Measured primary soot particle nucleation rates in the present laminar diffusion flames also were consistent with corresponding rates measured in laminar premixed flames and yielded a crude correlation in terms of acetylene and H concentrations and the temperature.

  6. Soot Formation in Laminar Acetylene/Air Diffusion Flames at Atmospheric Pressure. Appendix C

    Science.gov (United States)

    Xu, F.; Faeth, G. M.; Urban, D. L. (Technical Monitor); Yuan, Z.-G. (Technical Monitor)

    2000-01-01

    The flame structure and soot-formation (soot nucleation and growth) properties of axisymmetric laminar coflowing jet diffusion flames were studied experimentally. Test conditions involved acetylene-nitrogen jets burning in coflowing air at atmospheric pressure. Measurements were limited to the axes of the flames and included soot concentrations, soot temperatures, soot structure, major gas species concentrations, radical species (H, OH, and O) concentrations, and gas velocities. The results show that as distance increases along the axes of the flames, detectable soot formation begins when significant H concentrations are present, and ends when acetylene concentrations become small. Species potentially associated with soot oxidation-O2, CO2, H2O, O, and OH-are present throughout the soot-formation region so that soot formation and oxidation proceed at the same time. Strong rates of soot growth compared to soot nucleation early in the soot-formation process, combined with increased rates of soot nucleation and oxidation as soot formation proceeds, causes primary soot particle diameters to reach a maximum relatively early in the soot-formation process. Aggregation of primary soot particles proceeds, however, until the final stages of soot oxidation. Present measurements of soot growth (corrected for soot oxidation) in laminar diffusion flames were consistent with earlier measurements of soot growth in laminar premixed flames and exhibited encouraging agreement with existing hydrogen-abstraction/carbon-addition (HACA) soot growth mechanisms in the literature that were developed based on measurements within laminar premixed flames. Measured primary soot particle nucleation rates in the present laminar diffusion flames also were consistent with corresponding rates measured in laminar premixed flames and yielded a crude correlation in terms of acetylene and H concentrations and the temperature.

  7. Air pressure effects on sea level changes during the twentieth century

    Science.gov (United States)

    Piecuch, Christopher G.; Thompson, Philip R.; Donohue, Kathleen A.

    2016-10-01

    Interpretation of tide gauge data in terms sea level (η) and ocean dynamics requires estimates of air pressure (pa) to determine the ocean's isostatic response—the inverted barometer effect (ηib). Three gridded pa products (HadSLP2, NOAA-20CRv2, and ERA-20C) are used alongside meteorological station pa and tide gauge η records to evaluate the contribution of ηib to η changes over the twentieth century. Agreement between gridded products is better during more recent periods and over regions with good historical data coverage, whereas it is worse for earlier time periods or in ocean areas with poor observational data coverage. Comparison against station data reveals the presence of systematic errors in the gridded products, for example, such that uncertainties estimated through differencing the gridded products underestimate the true errors by roughly 40% on interannual and decadal time scales. Notwithstanding such correlated errors, gridded products are still useful for interpretation of tide gauge data. Removing gridded estimates of ηib from η records reduces spatial variance in centennial trends across tide gauges by 10-30%, formal errors in centennial trends from individual gauges by ˜5%, and the temporal variance in detrended records by 10-15% on average (depending on choice of gridded product). Results here advocate for making the ηib correction to tide gauge records in studies of ocean circulation and global η over long, multidecadal, and centennial time scales using an ensemble mean taken across several gridded ηib products.

  8. Atmospheric pressure He-air plasma jet: Breakdown process and propagation phenomenon

    Energy Technology Data Exchange (ETDEWEB)

    Begum, Asma [Independent University, Bangladesh, School of Engineering and Computer Science, Bashundhara, Dhaka (Bangladesh); Laroussi, Mounir [Old Dominion University, Department of Electrical and Computer Engineering, Norfolk, Virginia (United States); Pervez, Mohammad Rasel [Master Mind College, Department of Physics, Dhanmondi, Dhaka (Bangladesh)

    2013-06-15

    In this paper He-discharge (plasma jet/bullet) in atmospheric pressure air and its progression phenomenon has been studied experimentally using ICCD camera, optical emission spectroscopy (OES) and calibrated dielectric probe measurements. The repetitive nanosecond pulse has applied to a plasma pencil to generate discharge in the helium gas channel. The discharge propagation speed was measured from the ICCD images. The axial electric field distribution in the plasma jet is inferred from the optical emission spectroscopic data and from the probe measurement. The correlation between the jet velocities, jet length with the pulse duration is established. It shows that the plasma jet is not isolated from the input voltage along its propagation path. The discharge propagation speed, the electron density and the local and average electric field distribution along the plasma jet axis predicted from the experimental results are in good agreement with the data predicted by numerical simulation of the streamer propagation presented in different literatures. The ionization phenomenon of the discharge predicts the key ionization parameters, such as speed, peak electric field in the front, and electron density. The maximum local electric field measured by OES is 95 kV/cm at 1.3 cm of the jet axis, and average EF measured by probe is 24 kV/cm at the same place of the jet. The average and local electron density estimated are in the order of 10{sup 11} cm{sup -3} and it reaches to the maximum of 10{sup 12} cm{sup -3}.

  9. Deactivating bacteria with RF Driven Hollow Slot Microplasmas in Open Air at Atmospheric Pressure

    Science.gov (United States)

    Yu, Zengqi; Pruden, Amy; Sharma, Ashish; Collins, George

    2003-10-01

    A hollow slot discharge operating in open air at atmospheric pressure has demonstrated its ability to deactivate bacterial growth on nearby surfaces exposed to the RF driven plasma. The cold plasma exits from a hollow slot with a width of 0.2 mm and variable length of 1-35 cm. An internal electrode was powered by 13.56 MHz radio-frequency power at a voltage below 200 V. External electrically grounded slots face the work piece. The plasma plume extends millimeters to centimeter beyond the hollow slot toward the work piece to be irradiated. Argon-Oxygen gas mixtures, at 33 liters per minute flow, were passed through the electrodes and the downstream plasma was employed for the process, with treatment exposure time varied from 0.06 to 0.18 seconds. Bacterial cultures were fixed to 0.22 micron cellulose filter membranes and passed under the plasma at a controlled rate at a distance of about 5-10 millimeters from the grounded slot electrode. Preliminary studies on the effectiveness of the plasma for sterilization were carried out on E. coli. Cultures were grown overnight on the membranes after exposure and the resulting colony forming units (cfu) were determined in treated and untreated groups. In the plasma treated group, a 98.2% kill rate was observed with the lowest exposure time, and increased to 99.8% when the exposure time was tripled. These studies clearly demonstrate the ability of the RF-driven hollow slot atmospheric plasma to inhibit bacterial growth on surfaces.

  10. Inhibitory effect of silver nanoparticles mediated by atmospheric pressure air cold plasma jet against dermatophyte fungi.

    Science.gov (United States)

    Ouf, Salama A; El-Adly, Amira A; Mohamed, Abdel-Aleam H

    2015-10-01

    In an in vitro study with five clinical isolates of dermatophytes, the MIC(50) and MIC(100) values of silver nanoparticles (AgNPs) ranged from 5 to 16 and from 15 to 32 μg ml(- 1), respectively. The combined treatment of AgNPs with atmospheric pressure-air cold plasma (APACP) induced a drop in the MIC(50) and MIC100 values of AgNPs reaching 3-11 and 12-23 μg ml(- 1), respectively, according to the examined species. Epidermophyton floccosum was the most sensitive fungus to AgNPs, while Trichophyton rubrum was the most tolerant. AgNPs induced significant reduction in keratinase activity and an increase in the mycelium permeability that was greater when applied combined with plasma treatment. Scanning electron microscopy showed electroporation of the cell walls and the accumulation of AgNPs on the cell wall and inside the cells, particularly when AgNPs were combined with APACP treatment. An in vivo experiment with dermatophyte-inoculated guinea pigs indicated that the application of AgNPs combined with APACP was more efficacious in healing and suppressing disease symptoms of skin as compared with the application of AgNPs alone. The recovery from the infection reached 91.7 % in the case of Microsporum canis-inoculated guinea pigs treated with 13 μg ml(- 1) AgNPs combined with APACP treatment delivered for 2  min. The emission spectra indicated that the efficacy of APACP was mainly due to generation of NO radicals and excited nitrogen molecules. These reactive species interact and block the activity of the fungal spores in vitro and in the skin lesions of the guinea pigs. The results achieved are promising compared with fluconazole as reference antifungal drug.

  11. Fast step-response settling of micro electrostatic actuators operated at low air pressure using input shaping

    Science.gov (United States)

    Mol, L.; Rocha, L. A.; Cretu, E.; Wolffenbuttel, R. F.

    2009-07-01

    Squeeze-film damping is highly inadequate in low-pressure systems or in systems where air pressure and/or gap dimensions are poorly defined. Input shaping has been used to circumvent the oscillations typically associated with under-damped mass-spring-damper systems and drastically decrease the settling time. The proposed method does not rely on feedback but solely on the system dynamics. The required input signal is derived analytically from the differential equation describing the system. The resulting device response is simulated and experimentally verified on an electrostatically actuated microstructure. Settling occurs even faster than for an equivalent critically damped system.

  12. Effects of surface pressure on the properties of Langmuir monolayers and interfacial water at the air-water interface.

    Science.gov (United States)

    Lin, Wei; Clark, Anthony J; Paesani, Francesco

    2015-02-24

    The effects of surface pressure on the physical properties of Langmuir monolayers of palmitic acid (PA) and dipalmitoylphosphatidic acid (DPPA) at the air/water interface are investigated through molecular dynamics simulations with atomistic force fields. The structure and dynamics of both monolayers and interfacial water are compared across the range of surface pressures at which stable monolayers can form. For PA monolayers at T = 300 K, the untilted condensed phase with a hexagonal lattice structure is found at high surface pressure, while the uniformly tilted condensed phase with a centered rectangular lattice structure is observed at low surface pressure, in agreement with the available experimental data. A state with uniform chain tilt but no periodic spatial ordering is observed for DPPA monolayers on a Na(+)/water subphase at both high and low surface pressures. The hydrophobic acyl chains of both monolayers pack efficiently at all surface pressures, resulting in a very small number of gauche defects. The analysis of the hydrogen-bonding structure/dynamics at the monolayer/water interface indicates that water molecules hydrogen-bonded to the DPPA head groups reorient more slowly than those hydrogen-bonded to the PA head groups, with the orientational dynamics becoming significantly slower at high surface pressure. Possible implications for physicochemical processes taking place on marine aerosols in the atmosphere are discussed.

  13. Motor control of sound frequency in birdsong involves the interaction between air sac pressure and labial tension

    Science.gov (United States)

    Alonso, Rodrigo; Goller, Franz; Mindlin, Gabriel B.

    2014-03-01

    Frequency modulation is a salient acoustic feature of birdsong. Its control is usually attributed to the activity of syringeal muscles, which affect the tension of the labia responsible for sound production. We use experimental and theoretical tools to test the hypothesis that for birds producing tonal sounds such as domestic canaries (Serinus canaria), frequency modulation is determined by both the syringeal tension and the air sac pressure. For different models, we describe the structure of the isofrequency curves, which are sets of parameters leading to sounds presenting the same fundamental frequencies. We show how their shapes determine the relative roles of syringeal tension and air sac pressure in frequency modulation. Finally, we report experiments that allow us to unveil the features of the isofrequency curves.

  14. Long-term ambient air pollution exposure and risk of high blood pressure among citizens in Nis, Serbia.

    Science.gov (United States)

    Stanković, Aleksandra; Nikolić, Maja

    2016-01-01

    Epidemiological studies suggest that long-term exposure to air pollution increases the risk for high blood pressure (BP). The aim of our study is to evaluate any effects in BP in citizens exposed to long-term ambient air pollution. The subjects are 1136 citizens, aged 18-70 years, living for more than 5 years in the same home in the areas with a different level of air pollution. The air concentrations of black smoke and sulfur dioxide were determined in the period from 2001 to 2011. We measured systolic and diastolic BP and heart rate. Multivariate methods were used in the analysis. Alcohol consumption had the greatest influence on the incidence of hypertension as a risk factor (RR: 3.461; 95% CI: 1.72-6.93) and age had the least (RR: 1.23; 95% CI: 1.183-1.92). Exposure to air pollution increases risk for developing hypertension 2.5 times (95% CI: 1.46-4.49). Physical activity has proved to be statistically significant protective factor for the development of hypertension. Long-term exposure to low levels of main air pollutants is significantly associated with elevated risk of hypertension.

  15. Study of nanosecond discharges in different H2 air mixtures at atmospheric pressure for plasma-assisted applications

    Science.gov (United States)

    Bourdon, Anne; Kobayashi, Sumire; Bonaventura, Zdenek; Tholin, Fabien; Popov, Nikolay

    2016-09-01

    This paper presents 2D simulations of nanosecond pulsed discharges between two point electrodes in different H2/air mixtures and in air at atmospheric pressure. A fluid model is coupled with detailed kinetic schemes for air and different H2/air mixtures to simulate the discharge dynamics. First, as the positive and negative ionization waves propagate in the interelectrode gap, it has been observed that in H2/air mixtures with equivalence ratios between 0.3 and 2, major positive ions produced by the nanosecond discharge are N2+,O2+and HN2+.The discharge dynamics is shown to vary only slightly for equivalence ratios of the H2/air mixture between 0.3 and 2. Then, as the discharge transits to a nanosecond spark discharge, we have studied the different chemical reactions that lead to fast gas heating and to the production of radicals, as O,H and OH. Both thermal and chemical effects of the nanosecond spark discharge are of interest for plasma assisted combustion applications. This work has been supported by the project DRACO (Grant No. ANR-13-IS09-0004) and the french russian LIA Kappa.

  16. Transitions between corona, glow, and spark regimes of nanosecond repetitively pulsed discharges in air at atmospheric pressure

    OpenAIRE

    Pai, David,; Lacoste, Deanna,; Laux, C.

    2010-01-01

    International audience; In atmospheric pressure air preheated from 300 to 1000 K, the nanosecond repetitively pulsed (NRP) method has been used to generate corona, glow, and spark discharges. Experiments have been performed to determine the parameter space (applied voltage, pulse repetition frequency, ambient gas temperature, and interelectrode gap distance) of each discharge regime. In particular, the experimental conditions necessary for the glow regime of NRP discharges have been determine...

  17. Optimal frequency selection of multi-channel O2-band different absorption barometric radar for air pressure measurements

    Science.gov (United States)

    Lin, Bing; Min, Qilong

    2017-02-01

    Through theoretical analysis, optimal selection of frequencies for O2 differential absorption radar systems on air pressure field measurements is achieved. The required differential absorption optical depth between a radar frequency pair is 0.5. With this required value and other considerations on water vapor absorption and the contamination of radio wave transmission, frequency pairs of present considered radar system are obtained. Significant impacts on general design of differential absorption remote sensing systems are expected from current results.

  18. Human activity under high pressure: A case study on fluctuation scaling of air traffic controller's communication behaviors

    Science.gov (United States)

    Wang, Yanjun; Zhang, Qiqian; Zhu, Chenping; Hu, Minghua; Duong, Vu

    2016-01-01

    Recent human dynamics research has unmasked astonishing statistical characteristics such as scaling behaviors in human daily activities. However, less is known about the general mechanism that governs the task-specific activities. In particular, whether scaling law exists in human activities under high pressure remains an open question. In air traffic management system, safety is the most important factor to be concerned by air traffic controllers who always work under high pressure, which provides a unique platform to study human activity. Here we extend fluctuation scaling method to study air traffic controller's communication activity by investigating two empirical communication datasets. Taken the number of controlled flights as the size-like parameter, we show that the relationships between the average communication activity and its standard deviation in both datasets can be well described by Taylor's power law, with scaling exponent α ≈ 0.77 ± 0.01 for the real operational data and α ≈ 0.54 ± 0.01 for the real-time training data. The difference between the exponents suggests that human dynamics under pressure is more likely dominated by the exogenous force. Our findings may lead to further understanding of human behavior.

  19. Trace analysis of organics in air by corona discharge atmospheric pressure ionization using an electrospray ionization interface.

    Science.gov (United States)

    Nikolaev, Eugene; Riter, Leah S; Laughlin, Brian C; Handberg, Eric; Cooks, R Graham

    2004-01-01

    A corona discharge ion source operating at atmospheric pressure in the point-to-plane configuration was constructed by reconfiguring the ion source of a commercial electrospray ionization (ESI) quadrupole mass spectrometer. This new source allows direct air analysis without modification to the mass spectrometer. Detection and quantitation of semi-volatile compounds in air is demonstrated. The analytical performance of the system was established using the chemical warfare agent simulants methyl salicylate and dimethyl methylphosphonate. Limits of detection are 60 pptr in the negative-ion mode and 800 pptr in the positive-ion mode for methyl salicylate and 800 pptr in the negative-ion mode and 3.6 ppb in the positive-ion mode for dimethyl methylphosphonate. A linear response was observed from 60 pptr to 8 ppb for methyl salicylate in air in the negative-ionization mode. Cluster ion formation versus production of analyte ions was investigated and it was found that dry air or an elevated capillary interface temperature (130 degrees C) was needed to avoid extensive clustering, mostly of water. Reagent gases are not needed as proton sources, as is usually the case for atmospheric pressure chemical ionization, and this, together with the simplicity, sensitivity and speed of the technique, makes it promising for miniaturization and future field studies.

  20. Measuring air core characteristics of a pressure-swirl atomizer via a transparent acrylic nozzle at various Reynolds numbers

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Eun J.; Oh, Sang Youp; Kim, Ho Y.; Yoon, Sam S. [Dept. of Mechanical, Korea University Anamdong, 5-Ga, Sungbukgu, 136-713 Seoul (Korea); James, Scott C. [Thermal/Fluid Science and Engineering, Sandia National Labs, PO Box 969, Livermore, CA 94551 (United States)

    2010-11-15

    Because of thermal fluid-property dependence, atomization stability (or flow regime) can change even at fixed operating conditions when subject to temperature change. Particularly at low temperatures, fuel's high viscosity can prevent a pressure-swirl (or simplex) atomizer from sustaining a centrifugal-driven air core within the fuel injector. During disruption of the air core inside an injector, spray characteristics outside the nozzle reflect a highly unstable, nonlinear mode where air core length, Sauter mean diameter (SMD), cone angle, and discharge coefficient variability. To better understand injector performance, these characteristics of the pressure-swirl atomizer were experimentally investigated and data were correlated to Reynolds numbers (Re). Using a transparent acrylic nozzle, the air core length, SMD, cone angle, and discharge coefficient are observed as a function of Re. The critical Reynolds numbers that distinguish the transition from unstable mode to transitional mode and eventually to a stable mode are reported. The working fluids are diesel and a kerosene-based fuel, referred to as bunker-A. (author)

  1. 变频器在空压机恒压供气改造中的应用%Inverter in Transformation of Air Compressor Constant Pressure Air Supply

    Institute of Scientific and Technical Information of China (English)

    翟世宽

    2012-01-01

    Exist for traditional air compressor control to no-load operating power factor is low, serious power waste and two-cylinder temperature rise higher defect, through the use of inverter control system of the air compressor, piston compressor actual operation constant pressure air supply energy-saving air compressor running after the transformation was complete, stable, significant energy savings, and also to meet the requirements of production process.%针对空压机传统控制方式存在空载运行功率因数低、电能浪费严重及二级缸温升高等缺陷,同时根据活塞式空压机实际运行情况,通过采用变频器对空压机控制系统进行恒压供气节能改造.改造完成后,空压机运行稳定、节能效果明显,也满足了生产工艺的要求.

  2. Surface treatment of polypropylene (PP) film by 50 Hz dielectric barrier discharge produced in air and argon/air mixture at atmospheric pressure

    Science.gov (United States)

    Joshi, Ujjwal Man; Subedi, Deepak Prasad

    2015-07-01

    Thin films of polypropylene (PP) are treated for improving hydrophilicity using non-thermal plasma generated by 50 Hz line frequency dielectric barrier discharge produced in air and argon/air mixture at atmospheric pressure. PP samples before and after the treatments are studied using contact angle measurements, surface free energy calculations and scanning electron microscopy (SEM). Distilled water (H2O), glycerol (C3H8O3) and diiodomethane (CH2I2) are used as test liquids. The contact angle measurements between test liquids and PP samples are used to determine total surface free energy using sessile drop technique. PP films show a remarkable increase in surface free energy after plasma treatment. SEM analysis of the plasma-treated PP films shows that plasma treatment introduces greater roughness on the surface leading to the increased surface free energy. Furthermore, it is found that introducing a small quantity of argon can enhance the surface treatment remarkably.

  3. Surface treatment of high density polyethylene (HDPE film by 50 Hz dielectric barrier discharge produced in air and argon/air mixture at atmospheric pressure

    Directory of Open Access Journals (Sweden)

    Joshi Ujjwal Man

    2015-03-01

    Full Text Available Thin films of high density polyethylene (HDPE are treated for improving hydrophilicity using non-thermal plasma generated by 50 Hz line frequency dielectric barrier discharge produced in air and argon/air mixture at atmospheric pressure. HDPE samples before and after the treatment are studied using contact angle measurements, surface free energy calculations and atomic force microscopy (AFM. Distilled water (H2O, glycerol (C3H8O3 and diiodomethane (CH2I2 are used as test liquids. The contact angle measurements between test liquids and HDPE samples are used to determine total surface free energy using sessile drop technique. HDPE films show a remarkable increase in surface free energy after plasma treatment. AFM analysis of the plasma-treated HDPE films shows that plasma treatment introduces greater roughness on the surface leading to the increased surface free energy. Furthermore, it is found that introducing a small quantity of argon can enhance the surface treatment remarkably.

  4. Bench experiments comparing simulated inspiratory effort when breathing helium-oxygen mixtures to that during positive pressure support with air

    Directory of Open Access Journals (Sweden)

    Martin Andrew R

    2012-10-01

    Full Text Available Abstract Background Inhalation of helium-oxygen (He/O2 mixtures has been explored as a means to lower the work of breathing of patients with obstructive lung disease. Non-invasive ventilation (NIV with positive pressure support is also used for this purpose. The bench experiments presented herein were conducted in order to compare simulated patient inspiratory effort breathing He/O2 with that breathing medical air, with or without pressure support, across a range of adult, obstructive disease patterns. Methods Patient breathing was simulated using a dual-chamber mechanical test lung, with the breathing compartment connected to an ICU ventilator operated in NIV mode with medical air or He/O2 (78/22 or 65/35%. Parabolic or linear resistances were inserted at the inlet to the breathing chamber. Breathing chamber compliance was also varied. The inspiratory effort was assessed for the different gas mixtures, for three breathing patterns, with zero pressure support (simulating unassisted spontaneous breathing, and with varying levels of pressure support. Results Inspiratory effort increased with increasing resistance and decreasing compliance. At a fixed resistance and compliance, inspiratory effort increased with increasing minute ventilation, and decreased with increasing pressure support. For parabolic resistors, inspiratory effort was lower for He/O2 mixtures than for air, whereas little difference was measured for nominally linear resistance. Relatively small differences in inspiratory effort were measured between the two He/O2 mixtures. Used in combination, reductions in inspiratory effort provided by He/O2 and pressure support were additive. Conclusions The reduction in inspiratory effort afforded by breathing He/O2 is strongly dependent on the severity and type of airway obstruction. Varying helium concentration between 78% and 65% has small impact on inspiratory effort, while combining He/O2 with pressure support provides an additive

  5. Earth's air pressure 2.7 billion years ago constrained to less than half of modern levels

    Science.gov (United States)

    Som, Sanjoy M.; Buick, Roger; Hagadorn, James W.; Blake, Tim S.; Perreault, John M.; Harnmeijer, Jelte P.; Catling, David C.

    2016-06-01

    How the Earth stayed warm several billion years ago when the Sun was considerably fainter is the long-standing problem of the `faint young Sun paradox'. Because of negligible O2 and only moderate CO2 levels in the Archaean atmosphere, methane has been invoked as an auxiliary greenhouse gas. Alternatively, pressure broadening in a thicker atmosphere with a N2 partial pressure around 1.6-2.4 bar could have enhanced the greenhouse effect. But fossilized raindrop imprints indicate that air pressure 2.7 billion years ago (Gyr) was below twice modern levels and probably below 1.1 bar, precluding such pressure enhancement. This result is supported by nitrogen and argon isotope studies of fluid inclusions in 3.0-3.5 Gyr rocks. Here, we calculate absolute Archaean barometric pressure using the size distribution of gas bubbles in basaltic lava flows that solidified at sea level ~2.7 Gyr in the Pilbara Craton, Australia. Our data indicate a surprisingly low surface atmospheric pressure of Patm = 0.23 +/- 0.23 (2σ) bar, and combined with previous studies suggests ~0.5 bar as an upper limit to late Archaean Patm. The result implies that the thin atmosphere was rich in auxiliary greenhouse gases and that Patm fluctuated over geologic time to a previously unrecognized extent.

  6. Local distribution of wall static pressure and heat transfer on a smooth flat plate impinged by a slot air jet

    Science.gov (United States)

    Adimurthy, M.; Katti, Vadiraj V.

    2016-06-01

    Local distribution of wall static pressure and heat transfer on a smooth flat plate impinged by a normal slot air jet is experimental investigated. Present study focuses on the influence of jet-to-plate spacing (Z/D h ) (0.5-10) and Reynolds number (2500-20,000) on the fluid flow and heat transfer distribution. A single slot jet with an aspect ratio (l/b) of about 22 is chosen for the current study. Infrared Thermal Imaging technique is used to capture the temperature data on the target surface. Local heat transfer coefficients are estimated from the thermal images using `SMART VIEW' software. Wall static pressure measurement is carried out for the specified range of Re and Z/D h . Wall static pressure coefficients are seen to be independent of Re in the range between 5000 and 15,000 for a given Z/D h . Nu values are higher at the stagnation point for all Z/D h and Re investigated. For lower Z/D h and higher Re, secondary peaks are observed in the heat transfer distributions. This may be attributed to fluid translating from laminar to turbulent flow on the target plate. Heat transfer characteristics are explained based on the simplified flow assumptions and the pressure data obtained using Differential pressure transducer and static pressure probe. Semi-empirical correlation for the Nusselt number in the stagnation region is proposed.

  7. Research Update: Direct conversion of h-BN into pure c-BN at ambient temperatures and pressures in air

    Directory of Open Access Journals (Sweden)

    Jagdish Narayan

    2016-02-01

    Full Text Available We report a direct conversion of hexagonal boron nitride (h-BN into pure cubic boron nitride (c-BN by nanosecond laser melting at ambient temperatures and atmospheric pressure in air. According to the phase diagram, the transformation from h-BN into c-BN can occur only at high temperatures and pressures, as the hBN-cBN-Liquid triple point is at 3500 K/9.5 GPa. Using nanosecond laser melting, we have created super undercooled state and shifted this triple point to as low as 2800 K and atmospheric pressure. The rapid quenching from super undercooled state leads to formation of super undercooled BN (Q-BN. The c-BN phase is nucleated from Q-BN depending upon the time allowed for nucleation and growth.

  8. Research Update: Direct conversion of h-BN into pure c-BN at ambient temperatures and pressures in air

    Energy Technology Data Exchange (ETDEWEB)

    Narayan, Jagdish, E-mail: narayan@ncsu.edu; Bhaumik, Anagh [Department of Materials Science and Engineering, Centennial Campus, North Carolina State University, Raleigh, North Carolina 27695-7907 (United States)

    2016-02-01

    We report a direct conversion of hexagonal boron nitride (h-BN) into pure cubic boron nitride (c-BN) by nanosecond laser melting at ambient temperatures and atmospheric pressure in air. According to the phase diagram, the transformation from h-BN into c-BN can occur only at high temperatures and pressures, as the hBN-cBN-Liquid triple point is at 3500 K/9.5 GPa. Using nanosecond laser melting, we have created super undercooled state and shifted this triple point to as low as 2800 K and atmospheric pressure. The rapid quenching from super undercooled state leads to formation of super undercooled BN (Q-BN). The c-BN phase is nucleated from Q-BN depending upon the time allowed for nucleation and growth.

  9. Standard Test Method for Water Penetration of Flat Plate Solar Collectors by Uniform Static Air Pressure Difference

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1986-01-01

    1.1 This test method covers the determination of the resistance of flat plate solar collectors to water penetration when water is applied to their outer surfaces with a static air pressure at the outer surface higher than the pressure at the interior of the collector. 1.2 This test method is applicable to any flat plate solar collector. 1.3 The proper use of this test method requires a knowledge of the principles of pressure and deflection measurement. 1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Specific precautionary information is contained in Section 6.

  10. Influence of ambient air on the flowing afterglow of an atmospheric pressure Ar/O2 radiofrequency plasma

    CERN Document Server

    Duluard, C Y; Hubert, J; Reniers, F

    2016-01-01

    The influence of ambient air on the flowing afterglow of an atmospheric pressure Ar/O2 radiofrequency plasma has been investigated experimentally. Spatially resolved mass spectrometry and laser induced fluorescence on OH radicals were used to estimate the intrusion of air in between the plasma torch and the substrate as a function of the torch-to-substrate separation distance. No air is detected, within the limits of measurement uncertainties, for separation distances smaller than 5 mm. For larger distances, the effect of ambient air can no longer be neglected, and radial gradients in the concentrations of species appear. The Ar 4p population, determined through absolute optical emission spectroscopy, is seen to decrease with separation distance, whereas a rise in emission from the N2(C--B) system is measured. The observed decay in Ar 4p and N2(C) populations for separation distances greater than 9mm is partly assigned to the increasing collisional quenching rate by N2 and O2 molecules from the entrained air....

  11. FAST TRACK COMMUNICATION: Contrasting characteristics of sub-microsecond pulsed atmospheric air and atmospheric pressure helium-oxygen glow discharges

    Science.gov (United States)

    Walsh, J. L.; Liu, D. X.; Iza, F.; Rong, M. Z.; Kong, M. G.

    2010-01-01

    Glow discharges in air are often considered to be the ultimate low-temperature atmospheric pressure plasmas for numerous chamber-free applications. This is due to the ubiquitous presence of air and the perceived abundance of reactive oxygen and nitrogen species in air plasmas. In this paper, sub-microsecond pulsed atmospheric air plasmas are shown to produce a low concentration of excited oxygen atoms but an abundance of excited nitrogen species, UV photons and ozone molecules. This contrasts sharply with the efficient production of excited oxygen atoms in comparable helium-oxygen discharges. Relevant reaction chemistry analysed with a global model suggests that collisional excitation of O2 by helium metastables is significantly more efficient than electron dissociative excitation of O2, electron excitation of O and ion-ion recombination. These results suggest different practical uses of the two oxygen-containing atmospheric discharges, with air plasmas being well suited for nitrogen and UV based chemistry and He-O2 plasmas for excited atomic oxygen based chemistry.

  12. Influence of surface emission processes on a fast-pulsed dielectric barrier discharge in air at atmospheric pressure

    Science.gov (United States)

    Pechereau, François; Bonaventura, Zdeněk; Bourdon, Anne

    2016-08-01

    This paper presents simulations of an atmospheric pressure air discharge in a point-to-plane geometry with a dielectric layer parallel to the cathode plane. Experimentally, a discharge reignition in the air gap below the dielectrics has been observed. With a 2D fluid model, it is shown that due to the fast rise of the high voltage applied and the sharp point used, a first positive spherical discharge forms around the point. Then this discharge propagates axially and impacts the dielectrics. As the first discharge starts spreading on the upper dielectric surface, in the second air gap with a low preionization density of {{10}4}~\\text{c}{{\\text{m}}-3} , the 2D fluid model predicts a rapid reignition of a positive discharge. As in experiments, the discharge reignition is much slower, a discussion on physical processes to be considered in the model to increase the reignition delay is presented. The limit case with no initial seed charges in the second air gap has been studied. First, we have calculated the time to release an electron from the cathode surface by thermionic and field emission processes for a work function φ \\in ≤ft[3,4\\right] eV and an amplification factor β \\in ≤ft[100,220\\right] . Then a 3D Monte Carlo model has been used to follow the dynamics of formation of an avalanche starting from a single electron emitted at the cathode. Due to the high electric field in the second air gap, we have shown that in a few nanoseconds, a Gaussian cloud of seed charges is formed at a small distance from the cathode plane. This Gaussian cloud has been used as the initial condition of the 2D fluid model in the second air gap. In this case, the propagation of a double headed discharge in the second air gap has been observed and the reignition delay is in rather good agreement with experiments.

  13. Impact of two-way air flow due to temperature difference on preventing the entry of outdoor particles using indoor positive pressure control method.

    Science.gov (United States)

    Chen, Chun; Zhao, Bin; Yang, Xudong

    2011-02-28

    Maintaining positive pressure indoors using mechanical ventilation system is a popular control method for preventing the entry of outdoor airborne particles. The idea is, as long as the supply air flow rate is larger than return air flow rate, the pressure inside the ventilated room should be positive since the superfluous air flow must exfiltrate from air leakages or other openings of the room to the outdoors. Based on experimental and theoretical analyses this paper aims to show the impact of two-way air flow due to indoor/outdoor temperature difference on preventing the entry of outdoor particles using positive pressure control method. The indoor positive pressure control method is effective only when the size of the opening area is restricted to a certain level, opening degree less than 30° in this study, due to the two-way air flow effect induced by differential temperature. The theoretical model was validated using the experimental data. The impacts of two-way air flow due to temperature difference and the supply air flow rate were also analyzed using the theoretical model as well as experimental data. For real houses, it seems that the idea about the positive pressure control method for preventing the entry of outdoor particles has a blind side.

  14. 29 CFR 1915.172 - Portable air receivers and other unfired pressure vessels.

    Science.gov (United States)

    2010-07-01

    .... 1915.172 Section 1915.172 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) OCCUPATIONAL SAFETY AND HEALTH STANDARDS FOR... Engineers Boiler and Pressure Vessel Code, Section VIII, Rules for Construction of Unfired Pressure...

  15. Research on the water hammer protection of the long distance water supply project with the combined action of the air vessel and over-pressure relief valve

    Science.gov (United States)

    Li, D. D.; Jiang, J.; Zhao, Z.; Yi, W. S.; Lan, G.

    2013-12-01

    We take a concrete pumping station as an example in this paper. Through the calculation of water hammer protection with a specific pumping station water supply project, and the analysis of the principle, mathematical models and boundary conditions of air vessel and over-pressure relief valve we show that the air vessel can protect the water conveyance system and reduce the transient pressure damage due to various causes. Over-pressure relief valve can effectively reduce the water hammer because the water column re-bridge suddenly stops the pump and prevents pipeline burst. The paper indicates that the combination set of air vessel and over-pressure relief valve can greatly reduce the quantity of the air valve and can eliminate the water hammer phenomenon in the pipeline system due to the vaporization and water column separation and re-bridge. The conclusion could provide a reference for the water hammer protection of long-distance water supply system.

  16. Evaluation of Low-Pressure Drop Antimicrobial and Hybrid Air Filters

    Science.gov (United States)

    2006-09-01

    Pass Bioaerosol Removal Efficiencies of a Room Air Cleaner,” Karin K. Foarde, James T. Hanley, David S. Ensor , Peter Roessler Aerosol Science...Karin K. Foarde, James T. Hanley, Alan C. Veeck ASHRAE Journal 52-58 (2000) “Determine the Efficacy of Antimicrobial Treatments of Fibrous...Air Filters,” Karin K. Foarde, James T. Hanley ASHRAE Transactions: Research 4429 (RP-909): 156–170. “Development of a Method for Measuring Single

  17. Optimally accurate thermal-wave cavity photopyroelectric measurements of pressure-dependent thermophysical properties of air: theory and experiments.

    Science.gov (United States)

    Kwan, Chi-Hang; Matvienko, Anna; Mandelis, Andreas

    2007-10-01

    An experimental technique for the measurement of thermal properties of air at low pressures using a photopyroelectric (PPE) thermal-wave cavity (TWC) was developed. In addition, two theoretical approaches, a conventional one-dimensional thermal-wave model and a three-dimensional theory based on the Hankel integral, were applied to interpret the thermal-wave field in the thermal-wave cavity. The importance of radiation heat transfer mechanisms in a TWC was also investigated. Radiation components were added to the purely conductive model by linearizing the radiation heat transfer component at the cavity boundary. The experimental results indicate that the three-dimensional model is necessary to describe the PPE signal, especially at low frequencies where thermal diffusion length is large and sideways propagation of the thermal-wave field becomes significant. Radiation is found to be the dominant contributor of the PPE signal at high frequencies and large cavity lengths, where heat conduction across the TWC length is relatively weak. The three-dimensional theory and the Downhill Simplex algorithm were used to fit the experimental data and extract the thermal diffusivity of air and the heat transfer coefficient in a wide range of pressures from 760 to 2.6 Torr. It was shown that judicious adjustments of cavity length and computational best fits to frequency-scanned data using three-dimensional photopyroelectric theory lead to optimally accurate value measurements of thermal diffusivity and heat transfer coefficient at various pressures.

  18. Development of open air silicon deposition technology by silane-free atmospheric pressure plasma enhanced chemical transport under local ambient gas control

    Science.gov (United States)

    Naito, Teruki; Konno, Nobuaki; Yoshida, Yukihisa

    2016-07-01

    Open air silicon deposition was performed by combining silane-free atmospheric pressure plasma-enhanced chemical transport and a newly developed local ambient gas control technology. The effect of air contamination on silicon deposition was investigated using a vacuum chamber, and the allowable air contamination level was confirmed to be 3 ppm. The capability of the local ambient gas control head was investigated numerically and experimentally. A safe and clean process environment with air contamination less than 1 ppm was achieved. Combining these technologies, a microcrystalline silicon film was deposited in open air, the properties of which were comparable to those of silicon films deposited in a vacuum chamber.

  19. Define and Quantify the Physics of Air Flow, Pressure Drop and Aerosol Collection in Nuclear Grade HEPA Filters

    Energy Technology Data Exchange (ETDEWEB)

    Moore, Murray E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-02-23

    Objective: Develop a set of peer-review and verified analytical methods to adjust HEPA filter performance to different flow rates, temperatures and altitudes. Experimental testing will measure HEPA filter flow rate, pressure drop and efficiency to verify the analytical approach. Nuclear facilities utilize HEPA (High Efficiency Particulate Air) filters to purify air flow for workspace ventilation. However, the ASME AG-1 technical standard (Code on Nuclear Air and Gas Treatment) does not adequately describe air flow measurement units for HEPA filter systems. Specifically, the AG-1 standard does not differentiate between volumetric air flow in ACFM (actual cubic feet per minute)compared to mass flow measured in SCFM (standard cubic feet per minute). More importantly, the AG-1 standard has an overall deficiency for using HEPA filter devices at different air flow rates, temperatures, and altitudes. Technical Approach: The collection efficiency and pressure drops of 18 different HEPA filters will be measured over a range of flow rates, temperatures and altitudes. The experimental results will be compared to analytical scoping calculations. Three manufacturers have allocated six HEPA filters each for this effort. The 18 filters will be tested at two different flow rates, two different temperatures and two different altitudes. The 36 total tests will be conducted at two different facilities: the ATI Test facilities (Baltimore MD) and the Los Alamos National Laboratory (Los Alamos NM). The Radiation Protection RP-SVS group at Los Alamos has an aerosol wind tunnel that was originally designed to evaluate small air samplers. In 2010, modifications were started to convert the wind tunnel for HEPA filter testing. (Extensive changes were necessary for the required aerosol generators, HEPA test fixtures, temperature control devices and measurement capabilities.) To this date, none of these modification activities have been funded through a specific DOE or NNSA program. This is

  20. The reconstruction of air pressure in Gdańsk in the period of instrumental observations, 1739-2012

    Science.gov (United States)

    Filipiak, Janusz

    2015-04-01

    The purpose of the paper is to characterise the details of reconstruction of air pressure in Gdańsk in the whole period of regular instrumental records spanning the period 1739-2012. Gdańsk pressure series has been reconstructed by joining air pressure observations of 15 local shorter series. The entire instrumental series can be divided into three sub-periods: the Early Observers period, lasting to 1806, the First Meteorological Networks, covering the years from 1807 to 1875 and Modern Measurements begun in 1876. During the first period, observations were made from two to four times per day, sometimes even at midnight. In the 19th century and up to 1945 thrice-daily barometer readings were a standard, in the last few decades the density of data is much denser. A serious gap in the original daily data exists for the period 1849-1875, where it appears that no original source of data have survived. Selected data are presented in the form of five-day or monthly averages. Numerous errors made probably during the re-writing of original observers' data by their assistants were discovered during digitalization. Despite this the quality of observations can be regarded as good. Data have been corrected to provide a monthly-mean measure of atmospheric pressure in the unit of hPa at standard conditions, i.e. standard gravity, 0 °C and at sea level. Some inconsistencies may still arise as the procedure of the homogenization of air temperature is not completed and in case of a few oldest series air temperature was estimated. Numerous breakpoints were identified in the homogenisation of the series and they cannot be always linked to known causes. A reasonably detailed station history has been compiled by incorporating metadata contained in various written sources. These metadata have facilitated the homogenisation of the data series. Mean annual atmospheric pressure in Gdańsk in period 1739-2012 calculated on the basis of homogenized series was 1014.9 hPa. Mean seasonal

  1. Numerical Modelling of Soot Formation in Laminar Axisymmetric Ethylene-Air Coflow Flames at Atmospheric and Elevated Pressures

    KAUST Repository

    Abdelgadir, Ahmed

    2015-03-30

    A set of coflow diffusion flames are simulated to study the formation, growth, and oxidation of soot in flames of diluted hydrocarbon fuels, with focus on the effects of pressure. Firstly, we assess the ability of a high performance CFD solver, coupled with detailed transport and kinetic models, to reproduce experimental measurements of a series of ethylene-air coflow flames. Detailed finite rate chemistry describing the formation of Polycyclic Aromatic Hydro-carbons is used. Soot is modeled with a moment method and the resulting moment transport equations are solved with a Lagrangian numerical scheme. Numerical and experimental results are compared for various pressures. Finally, a sensitivity study is performed assessing the effect of the boundary conditions and kinetic mechanisms on the flame structure and stabilization properties.

  2. Impact of Spatial Resolution on Wind Field Derived Estimates of Air Pressure Depression in the Hurricane Eye

    Directory of Open Access Journals (Sweden)

    Linwood Jones

    2010-03-01

    Full Text Available Measurements of the near surface horizontal wind field in a hurricane with spatial resolution of order 1–10 km are possible using airborne microwave radiometer imagers. An assessment is made of the information content of the measured winds as a function of the spatial resolution of the imager. An existing algorithm is used which estimates the maximum surface air pressure depression in the hurricane eye from the maximum wind speed. High resolution numerical model wind fields from Hurricane Frances 2004 are convolved with various HIRAD antenna spatial filters to observe the impact of the antenna design on the central pressure depression in the eye that can be deduced from it.

  3. Electron properties and air mixing in radio frequency driven argon plasma jets at atmospheric pressure

    Energy Technology Data Exchange (ETDEWEB)

    Gessel, Bram van; Bruggeman, Peter [Department of Applied Physics, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven (Netherlands); Brandenburg, Ronny [Department of Applied Physics, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven (Netherlands); Leibniz Institute for Plasma Science and Technology (INP Greifswald), Felix-Hausdorff-Str. 2, D-17489 Greifswald (Germany)

    2013-08-05

    A time modulated radio frequency (RF) plasma jet operated with an Ar mixture is investigated by measuring the electron density and electron temperature using Thomson scattering. The measurements have been performed spatially resolved for two different electrode configurations and as a function of the plasma dissipated power and air concentration admixed to the Ar. Time resolved measurements of electron densities and temperatures during the RF cycle and after plasma power switch-off are presented. Furthermore, the influence of the plasma on the air entrainment into the effluent is studied using Raman scattering.

  4. Glottal airflow and transglottal air pressure measurements for male and female speakers in soft, normal, and loud voice.

    Science.gov (United States)

    Holmberg, E B; Hillman, R E; Perkell, J S

    1988-08-01

    Measurements on the inverse filtered airflow waveform (the "glottal waveform") and of estimated average transglottal pressure and glottal airflow were made from noninvasive recordings of productions of syllable sequences in soft, normal, and loud voice for 25 male and 20 female speakers. Statistical analyses showed that with change from normal to loud voice, both males and females produced loud voice with increased pressure, accompanied by increased ac flow and increased maximum airflow declination rate. With change from normal voice, soft voice was produced with decreased pressure, ac flow and maximum airflow declination rate, and increased dc and average flow. Within the loudness conditions, there was no significant male-female difference in air pressure. Several glottal waveform parameters separated males and females in normal and loud voice. The data indicate higher ac flow and higher maximum airflow declination rate for males. In soft voice, the male and female glottal waveforms were more alike, and there was no significant difference in maximum airflow declination rate. The dc flow did not differ significantly between males and females. Possible relevance to biomechanical differences and differences in voice source characteristics between males and females and across loudness conditions is discussed.

  5. Targeting cancer cells with reactive oxygen and nitrogen species generated by atmospheric-pressure air plasma.

    Directory of Open Access Journals (Sweden)

    Hak Jun Ahn

    Full Text Available The plasma jet has been proposed as a novel therapeutic method for cancer. Anticancer activity of plasma has been reported to involve mitochondrial dysfunction. However, what constituents generated by plasma is linked to this anticancer process and its mechanism of action remain unclear. Here, we report that the therapeutic effects of air plasma result from generation of reactive oxygen/nitrogen species (ROS/RNS including H2O2, Ox, OH-, •O2, NOx, leading to depolarization of mitochondrial membrane potential and mitochondrial ROS accumulation. Simultaneously, ROS/RNS activate c-Jun NH2-terminal kinase (JNK and p38 kinase. As a consequence, treatment with air plasma jets induces apoptotic death in human cervical cancer HeLa cells. Pretreatment of the cells with antioxidants, JNK and p38 inhibitors, or JNK and p38 siRNA abrogates the depolarization of mitochondrial membrane potential and impairs the air plasma-induced apoptotic cell death, suggesting that the ROS/RNS generated by plasma trigger signaling pathways involving JNK and p38 and promote mitochondrial perturbation, leading to apoptosis. Therefore, administration of air plasma may be a feasible strategy to eliminate cancer cells.

  6. Field test of two high-pressure, direct-contact downhole steam generators. Volume I. Air/diesel system

    Energy Technology Data Exchange (ETDEWEB)

    Marshall, B.W.

    1983-05-01

    As a part of the Project DEEP STEAM to develop technology to more efficiently utilize steam for the recovery of heavy oil from deep reservoirs, a field test of a downhole steam generator (DSG) was performed. The DSG burned No. 2 diesel fuel in air and was a direct-contact, high pressure device which mixed the steam with the combustion products and injected the resulting mixture directly into the oil reservoir. The objectives of the test program included demonstration of long-term operation of a DSG, development of operational methods, assessment of the effects of the steam/combustion gases on the reservoir and comparison of this air/diesel DSG with an adjacent oxygen/diesel direct contact generator. Downhole operation of the air/diesel DSG was started in June 1981 and was terminated in late February 1982. During this period two units were placed downhole with the first operating for about 20 days. It was removed, the support systems were slightly modified, and the second one was operated for 106 days. During this latter interval the generator operated for 70% of the time with surface air compressor problems the primary source of the down time. Thermal contact, as evidenced by a temperature increase in the production well casing gases, and an oil production increase were measured in one of the four wells in the air/diesel pattern. Reservoir scrubbing of carbon monoxide was observed, but no conclusive data on scrubbing of SO/sub x/ and NO/sub x/ were obtained. Corrosion of the DSG combustor walls and some other parts of the downhole package were noted. Metallurgical studies have been completed and recommendations made for other materials that are expected to better withstand the downhole combustion environment. 39 figures, 8 tables.

  7. Effect of inlet-air humidity, temperature, pressure, and reference Mach number on the formation of oxides of nitrogen in a gas turbine combustor

    Science.gov (United States)

    Marchionna, N. R.; Diehl, L. A.; Trout, A. M.

    1973-01-01

    Tests were conducted to determine the effect of inlet air humidity on the formation of oxides of nitrogen (NOx) from a gas turbine combustor. Combustor inlet air temperature ranged from 506 K (450 F) to 838 K (1050 F). The tests were primarily run at a constant pressure of 6 atmospheres and reference Mach number of 0.065. The NOx emission index was found to decrease with increasing inlet air humidity at a constant exponential rate: NOx = NOx0e-19H (where H is the humidity and the subscript 0 denotes the value at zero humidity). the emission index increased exponentially with increasing normalized inlet air temperature to the 1.14 power. Additional tests made to determine the effect of pressure and reference Mach number on NOx showed that the NOx emission index varies directly with pressure to the 0.5 power and inversely with reference Mach number.

  8. Rigid-flexible outer sheath model using slider linkage locking mechanism and air pressure for endoscopic surgery.

    Science.gov (United States)

    Yagi, Akihiko; Matsumiya, Kiyoshi; Masamune, Ken; Liao, Hongen; Dohi, Takeyoshi

    2006-01-01

    The objective of this paper is to develop an outer sheath for flexible endoscopic manipulators. This sheath can switch two states including flexible and rigid, and make a rigid curved path for inserting manipulators. The flexible mode can be curved into a required shape. The rigid mode can hold the shape of the sheath, and then keep the path for instruments. Through the managed path, the flexible manipulators become easy to reach the target. We proposed a serial multi joint model to realize the flexible mechanism. This model is composed of a set of frame units which are connected serially. Each unit can be rotated to a given angle around the center of the joint. We developed a slider-link mechanism and a gear stopper controlled by air pressure for rigid mode. We designed and fabricated the prototype with a diameter of 16 mm and length of 290 mm. The experiment showed that the device could be switched from the flexible mode to the rigid mode when the air pressure was over 150 kPa, and each joint could hold its angle against the maximum 400 mNm. The phantom experiment showed that the flexible devices are possible to transmit the wire tension to the endpoint of the manipulator without changing the curving shape with by the developed outer sheath device.

  9. Two-photon absorption laser induced fluorescence measurement of atomic oxygen density in an air atmospheric pressure plasma jet

    Science.gov (United States)

    Conway, Jim; Gogna, Gurusharan; Daniels, Stephen

    2016-09-01

    Two-photon Absorption Laser Induced Fluorescence (TALIF) is used to measure atomic oxygen number density [O] in an air Atmospheric Pressure Plasma Jet (APPJ). A novel technique based on photolysis of O2 is used to calibrate the TALIF system ensuring the same species (O) is probed during calibration and measurement. As a result, laser intensity can be increased outside the TALIF quadratic laser power region without affecting calibration reliability as any high intensity saturation effects will be identical for calibration and experiment. Higher laser intensity gives stronger TALIF signals helping overcome weak TALIF signals often experienced at atmospheric pressure due to collisional quenching. O2 photo-dissociation and two-photon excitation of the resulting [O] are both achieved within the same laser pulse. The photolysis [O] is spatially non-uniform and time varying. To allow valid comparison with [O] in a plasma, spatial and temporal correction factors are required. Knowledge of the laser pulse intensity I0(t), and wavelength allows correction factors to be found using a rate equation model. The air flow into the jet was fixed and the RF power coupled into the system varied. The resulting [O] was found to increase with RF power.

  10. Characterization of atmospheric pressure plasma treated pure cashmere and wool/cashmere textiles: Treatment in air/water vapor mixture

    Energy Technology Data Exchange (ETDEWEB)

    Zanini, Stefano, E-mail: stefano.zanini@mib.infn.it [Università degli Studi di Milano-Bicocca, Dipartimento di Fisica “G. Occhialini”, p.za della Scienza, 3, I-20126 Milano (Italy); Grimoldi, Elisa [Università degli Studi di Milano-Bicocca, Dipartimento di Fisica “G. Occhialini”, p.za della Scienza, 3, I-20126 Milano (Italy); Citterio, Attilio [Politecnico di Milano, Dipartimento di Chimica, Materiali ed Ingegneria Chimica “G. Natta”, Via Mancinelli 7, I-20131 Milano (Italy); Riccardi, Claudia, E-mail: riccardi@mib.infn.it [Università degli Studi di Milano-Bicocca, Dipartimento di Fisica “G. Occhialini”, p.za della Scienza, 3, I-20126 Milano (Italy)

    2015-09-15

    Highlights: • We treated cashmere and wool/cashmere textiles with atmospheric pressure plasma. • Wettability of the fabrics was increased. • The increment in wettability derived from a surface oxidation of the fibers. • Only minor etching effects were observed with scanning electron microscopy. - Abstract: We performed atmospheric pressure plasma treatments of pure cashmere and wool/cashmere textiles with a dielectric barrier discharge (DBD) in humid air (air/water vapor mixtures). Treatment parameters have been optimized in order to enhance the wettability of the fabrics without changing their bulk properties as well as their touch. A deep characterization has been performed to study the wettability, the surface morphologies, the chemical composition and the mechanical properties of the plasma treated textiles. The chemical properties of the plasma treated samples were investigated with attenuated total reflectance Fourier transform infrared (FTIR/ATR) spectroscopy and X-ray photoelectron microscopy (XPS). The analyses reveal a surface oxidation of the treated fabrics, which enhances their surface wettability. Morphological characterization of the treated fibers with scanning electron microscopy (SEM) reveals minor etching effects, an essential feature for the maintenance of the textile softness.

  11. EXPERIMENTAL INVESTIGATION ON HEAT TRANSFER AND PRESSURE DROP CHARACTERISTICS OF AIR FLOW OVER A STAGGERED FLAT TUBE BANK IN CROSSFLOW

    Directory of Open Access Journals (Sweden)

    M. Ishak

    2013-06-01

    Full Text Available This paper presents an experimental investigation into the heat transfer and pressure drop characteristics of air flow in a staggered flat tube bank in crossflow with laminar-forced convection. Measurements were conducted for sixteen tubes in the direction of flow and four tubes in rows. The air velocity varies between 0.6–1.0 m/s and the Reynolds number varied from 373 to 623. The total heat flux supplied in all tubes are changed from 967.92 to 3629.70 W/m2. The results indicate that the average Nusselt number for all the flat tubes increased by 11.46–46.42%, with the Reynolds numbers varying from 373 to 623 at the fixed heat flux. The average Nusselt number increased by 21.39–84%, and the total heat flux varyied between 967.92–3629.70 W/m2 with a constant Reynolds number Re = 498. In addition, the pressure drop decreased with an increase in the Reynolds number. A new mean Nusselt number-Reynolds number correlation was found, and the correlation yielded good predictions for the measured data with a confidence interval of 98.9%.

  12. Surface treatment of polypropylene (PP) film by 50 Hz dielectric barrier discharge produced in air and argon/air mixture at atmospheric pressure

    Energy Technology Data Exchange (ETDEWEB)

    Joshi, Ujjwal Man, E-mail: umjoshi@gmail.com; Subedi, Deepak Prasad, E-mail: deepaksubedi2001@yahoo.com [Department of Natural Sciences (Physics), School of Science, Kathmandu University P. O. Box No. 6250, Dhulikhel, Kathmandu, Nepal (India)

    2015-07-31

    Thin films of polypropylene (PP) are treated for improving hydrophilicity using non-thermal plasma generated by 50 Hz line frequency dielectric barrier discharge produced in air and argon/air mixture at atmospheric pressure. PP samples before and after the treatments are studied using contact angle measurements, surface free energy calculations and scanning electron microscopy (SEM). Distilled water (H{sub 2}O), glycerol (C{sub 3}H{sub 8}O{sub 3}) and diiodomethane (CH{sub 2}I{sub 2}) are used as test liquids. The contact angle measurements between test liquids and PP samples are used to determine total surface free energy using sessile drop technique. PP films show a remarkable increase in surface free energy after plasma treatment. SEM analysis of the plasma-treated PP films shows that plasma treatment introduces greater roughness on the surface leading to the increased surface free energy. Furthermore, it is found that introducing a small quantity of argon can enhance the surface treatment remarkably.

  13. Pressurized air injection in an axial hydro-turbine model for the mitigation of tip leakage cavitation

    Science.gov (United States)

    Rivetti, A.; Angulo, M.; Lucino, C.; Liscia, S.

    2015-12-01

    Tip leakage vortex cavitation in axial hydro-turbines may cause erosion, noise and vibration. Damage due to cavitation can be found at the tip of the runner blades on the low pressure side and the discharge ring. In some cases, the erosion follows an oscillatory pattern that is related to the number of guide vanes. That might suggest that a relationship exists between the flow through the guide vanes and the tip vortex cavitating core that induces this kind of erosion. On the other hand, it is known that air injection has a beneficial effect on reducing the damage by cavitation. In this paper, a methodology to identify the interaction between guide vanes and tip vortex cavitation is presented and the effect of air injection in reducing this particular kind of erosion was studied over a range of operating conditions on a Kaplan scale model. It was found that air injection, at the expense of slightly reducing the efficiency of the turbine, mitigates the erosive potential of tip leakage cavitation, attenuates the interaction between the flow through the guide vanes and the tip vortex and decreases the level of vibration of the structural components.

  14. Surface modification of polyester fabrics by atmospheric-pressure air/He plasma for color strength and adhesion enhancement

    Science.gov (United States)

    Zhang, Chunming; Zhao, Meihua; Wang, Libing; Qu, Lijun; Men, Yajing

    2017-04-01

    Surface properties of water-based pigmented inks for ink-jet printed polyester fabrics were modified with atmospheric-pressure air/He plasma to improve the color strength and pigment adhesion of the treated surfaces. The influence of various parameters, including the surface morphology, chemical compositions, surface energy and dynamic contact angles of the control and plasma treated samples was studied. Color strength and edge definition were used to evaluate the ink-jet printing performance of fabrics. The change in pigment adhesion to polyester fibers was analyzed by SEM (scanning electron microscopy). AFM (Atomic force microscope) and XPS (X-ray photoelectron spectroscopy) analyses indicated the increase in surface roughness and the oxygen-containing polar groups(Cdbnd O, Csbnd OH and COOH) reinforced the fixation of pigments on the fiber surface. The result from this study suggested that the improved pigment color yield was clearly affected by alteration of pigment adhesion enhanced by plasma surface modification. Polyester fabrics exhibited better surface property and ink-jet printing performance after the air/He mixture plasma treatment comparing with those after air plasma treatment.

  15. Evaluation of the constant pressure panel method (CPM) for unsteady air loads prediction

    Science.gov (United States)

    Appa, Kari; Smith, Michael J. C.

    1988-01-01

    This paper evaluates the capability of the constant pressure panel method (CPM) code to predict unsteady aerodynamic pressures, lift and moment distributions, and generalized forces for general wing-body configurations in supersonic flow. Stability derivatives are computed and correlated for the X-29 and an Oblique Wing Research Aircraft, and a flutter analysis is carried out for a wing wind tunnel test example. Most results are shown to correlate well with test or published data. Although the emphasis of this paper is on evaluation, an improvement in the CPM code's handling of intersecting lifting surfaces is briefly discussed. An attractive feature of the CPM code is that it shares the basic data requirements and computational arrangements of the doublet lattice method. A unified code to predict unsteady subsonic or supersonic airloads is therefore possible.

  16. Evaluation of analytical methodology for hydrocarbons in high pressure air and nitrogen systems. [data aquisition

    Science.gov (United States)

    1977-01-01

    Information regarding the safety limits of hydrocarbons in liquid and gaseous oxygen, the steps taken for hydrocarbon removal from liquified gases, and the analysis of the contaminants was searched and the results are presented. The safety of hydrocarbons in gaseous systems was studied, and the latest hydrocarbon test equipment and methodology is reviewed. A detailed sampling and analysis plan is proposed to evaluate high pressure GN2 and LOX systems.

  17. Numerical Modelling of Soot Formation in Laminar Axisymmetric Ethylene-Air Coflow Flames at Atmospheric and Elevated Pressures

    KAUST Repository

    Rakha, Ihsan Allah

    2015-05-01

    The steady coflow diffusion flame is a widely used configuration for studying combustion kinetics, flame dynamics, and pollutant formation. In the current work, a set of diluted ethylene-air coflow flames are simulated to study the formation, growth, and oxidation of soot, with a focus on the effects of pressure on soot yield. Firstly, we assess the ability of a high performance CFD solver, coupled with detailed transport and kinetic models, to reproduce experimental measurements, like the temperature field, the species’ concentrations and the soot volume fraction. Fully coupled conservation equations for mass, momentum, energy, and species mass fractions are solved using a low Mach number formulation. Detailed finite rate chemistry describing the formation of Polycyclic Aromatic Hydrocarbons up to cyclopenta[cd]pyrene is used. Soot is modeled using a moment method and the resulting moment transport equations are solved with a Lagrangian numerical scheme. Numerical and experimental results are compared for various pressures. Reasonable agreement is observed for the flame height, temperature, and the concentrations of various species. In each case, the peak soot volume fraction is predicted along the centerline as observed in the experiments. The predicted integrated soot mass at pressures ranging from 4-8 atm, scales as P2.1, in satisfactory agreement with the measured integrated soot pressure scaling (P2.27). Significant differences in the mole fractions of benzene and PAHs, and the predicted soot volume fractions are found, using two well-validated chemical kinetic mechanisms. At 4 atm, one mechanism over-predicts the peak soot volume fraction by a factor of 5, while the other under-predicts it by a factor of 5. A detailed analysis shows that the fuel tube wall temperature has an effect on flame stabilization.

  18. Discussion on Feasibility of Roto -jet Pressurizing Dissolving Air Method%射流旋喷加压溶气系统的可行性探讨

    Institute of Scientific and Technical Information of China (English)

    李新

    2012-01-01

    溶气系统是气浮净水系统中的重要组成部分,关系到溶气水的形成及能耗问题等,论述了射流器供气和旋喷泵加压两种溶气方式,集两种方式的优点提出了射流旋喷加压溶气新装置,并对装置在气浮净水中的可行性进行分析。%Dissolved air system is an important part of air - floatation water purification, it affects the formation of dissolved air and energy consumption. This paper introduced two ways: dissolving air by jet eductor and dissolving air by jet bump. on the basis, a new method: roto -jet pressurizing dissolving air is proposed, and then its feasibility is analyzed.

  19. Simulation of the propagation and reignition of atmospheric pressure air discharges behind a dielectric plane obstacle

    Science.gov (United States)

    Pechereau, Francois; Jansky, Jaroslav; Bourdon, Anne

    2012-10-01

    In recent years, experimental studies on flue gas treatment have demonstrated the efficiency of plasma assisted catalysis for the treatment of a wide range of pollutants at a low energetic cost. In plasma reactors, usual catalyst supports are pellets, monoliths or porous media, and then atmospheric pressure discharges have to interact with many obstacles and to propagate in microcavities and pores. As a first step to better understand atmospheric pressure discharge dynamics in these complex geometries, in this work, we have carried out numerical simulations using a 2D-axisymmetric fluid model for a point-to-plane discharge with a dielectric plane obstacle placed in the path of the discharge. First, we have simulated the discharge ignition at the point electrode, its propagation in the gap and its impact and expansion on the dielectric plane. Depending on the applied voltage, the dielectric plane geometry and permittivity, we have identified conditions for the reignition of a second discharge behind the plane obstacle. These conditions will be discussed and compared with recent experimental results on the same configuration.

  20. Investigating the electron density of multi-MeV X-ray-induced air plasmas at low pressures based on electromagnetic resonant cavity analysis

    Science.gov (United States)

    Ribière, M.; d'Almeida, T.; Cessenat, O.; Maulois, M.; Pouzalgues, R.; Crabos, B.; Delbos, C.; Garrigues, A.; Azaïs, B.

    2016-12-01

    We investigate air plasmas generated by multi-MeV pulsed X-rays at pressures ranging from 10-5 to 10-1 mbar. The experimental approach used for these studies is based on measurements of resonant frequencies damping and shift for different electromagnetic modes within a cylindrical cavity. Time-integrated electron densities in X-ray-induced air plasmas are inferred from the damping rate of the measured magnetic fields and their corresponding frequency shifts. In the present study, electron densities ranging from 108 to 109 cm-3 at pressures ranging from 10-3 to 10-1 mbar have been measured. Experimental results were confronted to 3D Maxwell-Vlasov Particle-In-Cell simulations incorporating a radiation-induced electric conductivity model. The method used in this work enables determining microscopic and macroscopic physical quantities within low pressure air plasmas generated by pulsed X-ray.

  1. A comparison between the dimensions of positive transtibial residual limb molds prepared by air pressure casting and weight-bearing casting methods

    Science.gov (United States)

    Hajiaghaei, Behnam; Ebrahimi, Ismail; Kamyab, Mojtaba; Saeedi, Hassan; Jalali, Maryam

    2016-01-01

    Background: Creating a socket with proper fit is an important factor to ensure the comfort and control of prosthetic devices. Several techniques are commonly used to cast transtibial stumps but their effect on stump shape deformation is not well understood. This study compares the dimensions, circumferences and volumes of the positive casts and also the socket comfort between two casting methods. Our hypothesis was that the casts prepared by air pressure method have less volume and are more comfortable than those prepared by weight bearing method. Methods: Fifteen transtibial unilateral amputees participated in the study. Two weight bearing and air pressure casting methods were utilized for their residual limbs. The diameters and circumferences of various areas of the residual limbs and positive casts were compared. The volumes of two types of casts were measured by a volumeter and compared. Visual Analogue Scale (VAS) was used to measure the sockets fit comfort. Results: Circumferences at 10 and 15 cm below the patella on the casts were significantly smaller in air pressure casting method compared to the weight bearing method (p=0.00 and 0.01 respectively). The volume of the cast in air pressure method was lower than that of the weight bearing method (p=0.006). The amputees found the fit of the sockets prepared by air pressure method more comfortable than the weight bearing sockets (p=0.015). Conclusion: The air pressure casting reduced the circumferences of the distal portion of residual limbs which has more soft tissue and because of its snug fit it provided more comfort for amputees, according to the VAS measurements. PMID:27390711

  2. Temperature dependence of evaporation coeffcient of water in air and nitrogen under atmospheric pressure; study in water droplets

    CERN Document Server

    Zientara, M; Kolwas, K; Kolwas, M

    2008-01-01

    The evaporation coefficients of water in air and nitrogen were found as a function of temperature, by studying the evaporation of pure water droplet. The droplet was levitated in an electrodynamic trap placed in a climatic chamber maintaining atmospheric pressure. Droplet radius evolution and evaporation dynamics were studied with high precision by analyzing the angle-resolved light scattering Mie interference patterns. A model of quasi-stationary droplet evolution, accounting for the kinetic effects near the droplet surface was applied. In particular, the effect of thermal effusion (a short range analogue of thermal diffusion) was discussed and accounted for. The evaporation coefficient \\alpha in air and in nitrogen were found equal. \\alpha was found to decrease from ~ 0.18 to ~ 0.13 for the temperature range from 273.1 K to 293.1 K and follow the trend given by Arrhenius formula. The agreement with condensation coefficient values obtained with essentially different method by Li et al.[1] was found excellent...

  3. Novel atmospheric pressure plasma device releasing atomic hydrogen: reduction of microbial-contaminants and OH radicals in the air

    Science.gov (United States)

    Nojima, Hideo; Park, Rae-Eun; Kwon, Jun-Hyoun; Suh, Inseon; Jeon, Junsang; Ha, Eunju; On, Hyeon-Ki; Kim, Hye-Ryung; Choi, Kyoung Hui; Lee, Kwang-Hee; Seong, Baik-Lin; Jung, Hoon; Kang, Shin Jung; Namba, Shinichi; Takiyama, Ken

    2007-01-01

    A novel atmospheric pressure plasma device releasing atomic hydrogen has been developed. This device has specific properties such as (1) deactivation of airborne microbial-contaminants, (2) neutralization of indoor OH radicals and (3) being harmless to the human body. It consists of a ceramic plate as a positive ion generation electrode and a needle-shaped electrode as an electron emission electrode. Release of atomic hydrogen from the device has been investigated by the spectroscopic method. Optical emission of atomic hydrogen probably due to recombination of positive ions, H+(H2O)n, generated from the ceramic plate electrode and electrons emitted from the needle-shaped electrode have been clearly observed in the He gas (including water vapour) environment. The efficacy of the device to reduce airborne concentrations of influenza virus, bacteria, mould fungi and allergens has been evaluated. 99.6% of airborne influenza virus has been deactivated with the operation of the device compared with the control test in a 1 m3 chamber after 60 min. The neutralization of the OH radical has been investigated by spectroscopic and biological methods. A remarkable reduction of the OH radical in the air by operation of the device has been observed by laser-induced fluorescence spectroscopy. The cell protection effects of the device against OH radicals in the air have been observed. Furthermore, the side effects have been checked by animal experiments. The harmlessness of the device has been confirmed.

  4. Quantitative Analysis of Spectral Interference of Spontaneous Raman Scattering in High-Pressure Fuel-Rich H2-Air Combustion

    Science.gov (United States)

    Kojima, Jun; Nguyen, Quang-Viet

    2004-01-01

    We present a theoretical study of the spectral interferences in the spontaneous Raman scattering spectra of major combustion products in 30-atm fuel-rich hydrogen-air flames. An effective methodology is introduced to choose an appropriate line-shape model for simulating Raman spectra in high-pressure combustion environments. The Voigt profile with the additive approximation assumption was found to provide a reasonable model of the spectral line shape for the present analysis. The rotational/vibrational Raman spectra of H2, N2, and H2O were calculated using an anharmonic-oscillator model using the latest collisional broadening coefficients. The calculated spectra were validated with data obtained in a 10-atm fuel-rich H2-air flame and showed excellent agreement. Our quantitative spectral analysis for equivalence ratios ranging from 1.5 to 5.0 revealed substantial amounts of spectral cross-talk between the rotational H2 lines and the N2 O-/Q-branch; and between the vibrational H2O(0,3) line and the vibrational H2O spectrum. We also address the temperature dependence of the spectral cross-talk and extend our analysis to include a cross-talk compensation technique that removes the nterference arising from the H2 Raman spectra onto the N2, or H2O spectra.

  5. Management of Total Pressure Recovery, Distortion and High Cycle Fatigue in Compact Air Vehicle Inlets

    Science.gov (United States)

    Anderson, Bernhard H.; Baust, Henry D.; Agrell, Johan

    2002-01-01

    It is the purpose of this study to demonstrate the viability and economy of Response Surface Methods (RSM) and Robustness Design Concepts (RDC) to arrive at micro-secondary flow control installation designs that maintain optimal inlet performance over a range of the mission variables. These statistical design concepts were used to investigate the robustness properties of 'low unit strength' micro-effector installations. 'Low unit strength' micro-effectors are micro-vanes set at very low angles-of-incidence with very long chord lengths. They were designed to influence the near wall inlet flow over an extended streamwise distance, and their advantage lies in low total pressure loss and high effectiveness in managing engine face distortion.

  6. Atmospheric Pressure Corrections in Geodesy and Oceanography: a Strategy for Handling Air Tides

    Science.gov (United States)

    Ponte, Rui M.; Ray, Richard D.

    2003-01-01

    Global pressure data are often needed for processing or interpreting modern geodetic and oceanographic measurements. The most common source of these data is the analysis or reanalysis products of various meteorological centers. Tidal signals in these products can be problematic for several reasons, including potentially aliased sampling of the semidiurnal solar tide as well as the presence of various modeling or timing errors. Building on the work of Van den Dool and colleagues, we lay out a strategy for handling atmospheric tides in (re)analysis data. The procedure also offers a method to account for ocean loading corrections in satellite altimeter data that are consistent with standard ocean-tide corrections. The proposed strategy has immediate application to the on-going Jason-1 and GRACE satellite missions.

  7. Magnetic Ignition of Pulsed Gas Discharges in Air of Low Pressure in a Coaxial Plasma Gun

    Science.gov (United States)

    Thom, Karlheinz; Norwood, Joseph, Jr.

    1961-01-01

    The effect of an axial magnetic field on the breakdown voltage of a coaxial system of electrodes has been investigated by earlier workers. For low values of gas pressure times electrode spacing, the breakdown voltage is decreased by the application of the magnetic field. The electron cyclotron radius now assumes the role held by the mean free path in nonmagnetic discharges and the breakdown voltage becomes a function of the magnetic flux density. In this paper the dependence of the formative time lag as a function of the magnetic flux density is established and the feasibility of using a magnetic field for igniting high-voltage, high-current discharges is shown through theory and experiment. With a 36 microfarad capacitor bank charged to 48,000 volts, a peak current of 1.3 x 10( exp 6) amperes in a coaxial type of plasma gun was achieved with a current rise time of only 2 microseconds.

  8. Cellular attachment and differentiation on titania nanotubes exposed to air- or nitrogen-based non-thermal atmospheric pressure plasma.

    Directory of Open Access Journals (Sweden)

    Hye Yeon Seo

    Full Text Available The surface topography and chemistry of titanium implants are important factors for successful osseointegration. However, chemical modification of an implant surface using currently available methods often results in the disruption of topographical features and the loss of beneficial effects during the shelf life of the implant. Therefore, the aim of this study was to apply the recently highlighted portable non-thermal atmospheric pressure plasma jet (NTAPPJ, elicited from one of two different gas sources (nitrogen and air, to TiO2 nanotube surfaces to further improve their osteogenic properties while preserving the topographical morphology. The surface treatment was performed before implantation to avoid age-related decay. The surface chemistry and morphology of the TiO2 nanotube surfaces before and after the NTAPPJ treatment were determined using a field-emission scanning electron microscope, a surface profiler, a contact angle goniometer, and an X-ray photoelectron spectroscope. The MC3T3-E1 cell viability, attachment and morphology were confirmed using calcein AM and ethidium homodimer-1 staining, and analysis of gene expression using rat mesenchymal stem cells was performed using a real-time reverse-transcription polymerase chain reaction. The results indicated that both portable nitrogen- and air-based NTAPPJ could be used on TiO2 nanotube surfaces easily and without topographical disruption. NTAPPJ resulted in a significant increase in the hydrophilicity of the surfaces as well as changes in the surface chemistry, which consequently increased the cell viability, attachment and differentiation compared with the control samples. The nitrogen-based NTAPPJ treatment group exhibited a higher osteogenic gene expression level than the air-based NTAPPJ treatment group due to the lower atomic percentage of carbon on the surface that resulted from treatment. It was concluded that NTAPPJ treatment of TiO2 nanotube surfaces results in an increase in

  9. Effect of airstream velocity on mean drop diameters of water sprays produced by pressure and air atomizing nozzles. [for combustion studies

    Science.gov (United States)

    Ingebo, R. D.

    1977-01-01

    A scanning radiometer was used to determine the effect of airstream velocity on the mean drop diameter of water sprays produced by pressure atomizing and air atomizing fuel nozzles used in previous combustion studies. Increasing airstream velocity from 23 to 53.4 meters per second reduced the Sauter mean diameter by approximately 50 percent with both types of fuel nozzles. The use of a sonic cup attached to the tip of an air assist nozzle reduced the Sauter mean diameter by approximately 40 percent. Test conditions included airstream velocities of 23 to 53.4 meters per second at 293 K and atmospheric pressure.

  10. Treatment of poly(ethylene terephthalate) foils by atmospheric pressure air dielectric barrier discharge and its influence on cell growth

    Energy Technology Data Exchange (ETDEWEB)

    Kuzminova, Anna [Department of Macromolecular Physics, Faculty of Mathematics and Physics, Charles University, V Holešovickách 2, 180 00 Praha 8 (Czech Republic); Vandrovcová, Marta [Institute of Physiology, Academy of Sciences of the Czech Republic, Vídeňská 1083, 142 20 Prague 4 (Czech Republic); Shelemin, Artem [Department of Macromolecular Physics, Faculty of Mathematics and Physics, Charles University, V Holešovickách 2, 180 00 Praha 8 (Czech Republic); Kylián, Ondřej, E-mail: ondrej.kylian@gmail.com [Department of Macromolecular Physics, Faculty of Mathematics and Physics, Charles University, V Holešovickách 2, 180 00 Praha 8 (Czech Republic); Choukourov, Andrei; Hanuš, Jan [Department of Macromolecular Physics, Faculty of Mathematics and Physics, Charles University, V Holešovickách 2, 180 00 Praha 8 (Czech Republic); Bačáková, Lucie [Institute of Physiology, Academy of Sciences of the Czech Republic, Vídeňská 1083, 142 20 Prague 4 (Czech Republic); Slavínská, Danka; Biederman, Hynek [Department of Macromolecular Physics, Faculty of Mathematics and Physics, Charles University, V Holešovickách 2, 180 00 Praha 8 (Czech Republic)

    2015-12-01

    Highlights: • Effect of atmospheric pressure DBD plasma on PET foils was investigated. • DBD treatment causes increase in surface density of O-containing functional groups. • DBD plasma causes increase of wettability, roughness and complex modulus of PET. • DBD treatment positively influences cells growth on PET. • Enhancement of cell growth on treated PET depends on the cell type. - Abstract: In this contribution an effect of dielectric barrier discharge (DBD) sustained in air at atmospheric pressure on surface properties of poly(ethylene terephthalate) (PET) foils is studied. It is found that exposure of PET to DBD plasma leads to rapid changes of surface chemical composition, wettability, surface morphology as well as mechanical properties of PET surface. In addition, based on biological tests that were performed using two cell types (Saos-2 human osteoblast-like cells and HUVEC human umbilical vein endothelial cells), it may be concluded that DBD plasma treatment positively influences cell growth on PET. This effect was found to be connected predominantly with increased surface energy and oxygen content of the surface of treated PET foils.

  11. Aging Characteristics on Epoxy Resin Surface Under Repetitive Microsecond Pulses in Air at Atmospheric Pressure

    Science.gov (United States)

    Xie, Qing; Liu, Xiong; Zhang, Cheng; Wang, Ruixue; Rao, Zhangquan; Shao, Tao

    2016-03-01

    Research on aging characteristics of epoxy resin (EP) under repetitive microsecond pulses is important for the design of insulating materials in high power apparatus. It is because that very fast transient overvoltage always occurs in a power system, which causes flashover and is one of the main factors causing aging effects of EP materials. Therefore, it is essential to obtain a better understanding of the aging effect on an EP surface resulting from flashover. In this work, aging effects on an EP surface were investigated by surface flashover discharge under repetitive microsecond pulses in atmospheric pressure. The investigations of parameters such as the surface micro-morphology and chemical composition of the insulation material under different degrees of aging were conducted with the aid of measurement methods such as atomic force microscopy (AFM), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). Results showed that with the accumulation of aging energy on the material surface, the particles formed on the material surface increased both in number and size, leading to the growth of surface roughness and a reduction in the water contact angle; the surface also became more absorbent. Furthermore, in the aging process, the molecular chains of EP on the surface were broken, resulting in oxidation and carbonisation. supported by the Natural Science Foundation of Hebei Province (No. E2015502081), National Natural Science Foundation of China (Nos. 51222701, 51307060), and the National Basic Research Program of China (No. 2014CB239505-3)

  12. Study of a Filamentary Dielectric Barrier Discharge in Air at Atmospheric Pressure

    Science.gov (United States)

    Celestin, Sebastien; Zeghondy, Barbar; Guaitella, Olivier; Bourdon, Anne; Rousseau, Antoine

    2006-10-01

    Dielectric Barrier Discharges (DBD) at atmospheric pressure have many applications, for instance ozone production, surface treatment, and waste gas treatment. Generally, such a discharge is filamentary but it can be diffuse under particular conditions. Understanding the formation of the filament, which is an ionization wave or so-called ``streamer'', is very hard theoretically, numerically, and experimentally. This is due, first, to the non-linearity of the equations concerned, and second, because of the scaling in space and time of this phenomenon: a streamer has a radius on the order of a few microns, and propagates through distances of several centimeters in a few nanoseconds. In this study we will present the results obtained in experiments and in simulations for a plane-to-plane DBD. We electrically characterized this device and have observed collective effects that are still poorly understood. A point-to-plane DBD has also been studied for producing a much more localized discharge. In parallel with the experimental study we have developed a numerical model based on the Immersed Boundary Method (IBM) to introduce an electrode having a complex geometry into a structured Cartesian mesh. The first results of the code will be discussed.

  13. High intensity interior aircraft noise increases the risk of high diastolic blood pressure in Indonesian Air Force pilots

    Directory of Open Access Journals (Sweden)

    Minarma Siagian

    2009-12-01

    Full Text Available Aim: To analyze the effects of aircraft noise, resting pulse rate, and other factors on the risk of high diastolic blood pressure (DBP in Indonesian Air Force pilots.Methods: A nested case-control study was conducted using data extracted from annual medical check-ups indoctrination aerophysiologic training records at the Saryanto Aviation and Aerospace Health Institute (LAKESPRA in Jakarta from January 2003 – September 2008. For analysis of DBP: the case group with DBP ≥ 90 mmHg were compared with contral group with DBP < 79 mmHG. One case matched to 12 controls.Results: Out of 567 pilots, 544 (95.9% had complete medical records. For this analysis there were 40 cases of high DBP and 480 controls for DBP. Pilots exposed to aircraft noise 90-95 dB rather than 70-80 dB had a 2.7-fold increase for high DBP [adjusted odds ratio (ORa = 2.70; 95% confi dence interval (CI = 1.05-6.97]. Pilots with resting pulse rates of ≥ 81/minute rather than ≤ 80/minute had a 2.7-fold increase for high DBP (ORa = 2.66; 95% CI = 1.26-5.61. In terms of total fl ight hours, pilots who had 1401-11125 hours rather than 147-1400 hours had a 3.2-fold increase for high DBP (ORa = 3.18; 95% CI = 1.01-10.03.Conclusion: High interior aircraft noise, high total flight hours,  and high resting pulse rate, increased risk for high DBP. Self assessment of resting pulse rate can be used to control the risk of high DBP. (Med J Indones 2009; 276: 276-82Keywords: diastolic blood pressure, aircraft noise, resting pulse rate, military pilots

  14. Low-pressure catalytic wet-air oxidation of a high-strength industrial wastewater using Fenton's reagent.

    Science.gov (United States)

    Biçaksiz, Zeliha; Aytimur, Gülin; Atalay, Süheyda

    2008-06-01

    Wastewater from the Afyon Alkaloids Factory (Afyon, Turkey) was subjected to low-pressure catalytic wet-air oxidation (CWAO) using Fenton's reagent, and the optimal reaction conditions were investigated. The CWAO using Fenton's reagent was applied to the factory effluent, diluted factory effluent, and aerobically pretreated wastewater. To find the optimum quantities of reagents, ferrous iron (Fe(+2))-to-substrate ratios of 1:10, 1:25, and 1:50 and hydrogen peroxide (H2O2)-to-Fe(+2) ratios of 1, 5, and 10 were investigated, and the treatment was carried out at different temperatures. High chemical oxygen demand (COD) removals were obtained at 50 degrees C, with the Fe(+2)-to-substrate ratio range between 1:10 and 1:25. The change in H2O2-to-Fe(+2) ratios did not cause any considerable effect. Also, the percentages of COD removals were nearly the same, so the ratio H2O2:Fe(+2):1 is recommended. Aerobic pretreatment seems to be effective. On the other hand, no enhancement was observed in the case of the diluted wastewater.

  15. Influence of Surface Resistivity and Temperature on Variation with Time of Current Pulses in Air at Optimum Pressure

    Directory of Open Access Journals (Sweden)

    S.G. Pimpale

    1977-04-01

    Full Text Available The variation of discharge current pulses with the surface nature of electrodes has been investigated by producing discharge in the intense ionizing zone of two ozonizers (A&B containing pure, dry air at a pressure of 4 & 10mm of mercury respectively. The course of reaction in the tube A showed that the periodic rise and fall of discharge counts through a series of recurrences whose amplitude varied randomly. During this reaction, steady potential, temperature of the electrolytic bath, counting time and pulse height were kept fixed. The phenomenon obtained for both the tubes is produced within a critical range of conditions. The results have been interpreted on the basis of activated adsorption at a temperature of 90 degree and 100 degree Centigrade and discussed on the theoretical grounds of change of surface resistivity upon the glass walls. Use of different coatings on annular surface in the same system with appropriate levels of electrolytic solution for a definite value of height-pulses and temperature, etc. shows significant variations in the discharge counts.

  16. Transitions between corona, glow, and spark regimes of nanosecond repetitively pulsed discharges in air at atmospheric pressure

    Science.gov (United States)

    Pai, David Z.; Lacoste, Deanna A.; Laux, Christophe O.

    2010-05-01

    In atmospheric pressure air preheated from 300 to 1000 K, the nanosecond repetitively pulsed (NRP) method has been used to generate corona, glow, and spark discharges. Experiments have been performed to determine the parameter space (applied voltage, pulse repetition frequency, ambient gas temperature, and interelectrode gap distance) of each discharge regime. In particular, the experimental conditions necessary for the glow regime of NRP discharges have been determined, with the notable result that there exists a minimum and maximum gap distance for its existence at a given ambient gas temperature. The minimum gap distance increases with decreasing gas temperature, whereas the maximum does not vary appreciably. To explain the experimental results, an analytical model is developed to explain the corona-to-glow (C-G) and glow-to-spark (G-S) transitions. The C-G transition is analyzed in terms of the avalanche-to-streamer transition and the breakdown field during the conduction phase following the establishment of a conducting channel across the discharge gap. The G-S transition is determined by the thermal ionization instability, and we show analytically that this transition occurs at a certain reduced electric field for the NRP discharges studied here. This model shows that the electrode geometry plays an important role in the existence of the NRP glow regime at a given gas temperature. We derive a criterion for the existence of the NRP glow regime as a function of the ambient gas temperature, pulse repetition frequency, electrode radius of curvature, and interelectrode gap distance.

  17. Influence of pulsed nanosecond volume discharge in atmospheric-pressure air on the electrical characteristics of MCT epitaxial films

    Science.gov (United States)

    Grigoryev, Denis V.; Voitsekhovskii, Alexandr V.; Lozovoy, Kirill A.; Nesmelov, Sergey N.; Dzyadukh, Stanislav M.; Tarasenko, Viktor F.; Shulepov, Michail A.; Dvoretskii, Sergei A.

    2015-12-01

    The purpose of this paper was investigating the effect of volume nanosecond discharge in air at atmospheric pressure on the electro-physical properties of the HgCdTe (MCT) epitaxial films grown by molecular beam epitaxy. Hall measurements of electro-physical parameters of MCT samples after irradiation have shown that there is a layer of epitaxial films exhibiting n-type conductivity that is formed in the near-surface area. After more than 600 pulses of influence parameters and thickness of the resulting n-layer is such that the measured field dependence of Hall coefficient corresponds to the material of n-type conductivity. Also it is shown that the impact of the discharge leads to significant changes in electro-physical characteristics of MIS structures. This fact is demonstrated by increase in density of positive fixed charge, change in the hysteresis type of the capacitance-voltage characteristic, an increase in density of surface states. The preliminary results show that it is possible to use such actions in the development of technologies of the controlled change in the properties of MCT.

  18. Numerical Analysis on the Influence of Thermal Effects on Oil Flow Characteristic in High-Pressure Air Injection (HPAI Process

    Directory of Open Access Journals (Sweden)

    Hu Jia

    2012-01-01

    Full Text Available In previous laboratory study, we have shown the thermal behavior of Keke Ya light crude oil (Tarim oilfield, branch of CNPC for high-pressure air injection (HPAI application potential study. To clarify the influences of thermal effects on oil production, in this paper, we derived a mathematical model for calculating oil flow rate, which is based on the heat conduction property in porous media from the combustion tube experiment. Based on remarkably limited knowledge consisting of very global balance arguments and disregarding all the details of the mechanisms in the reaction zone, the local governing equations are formulated in a dimensionless form. We use finite difference method to solve this model and address the study by way of qualitative analysis. The time-space dimensionless oil flow rate (qD profiles are established for comprehensive studies on the oil flow rate characteristic affected by thermal effects. It also discusses how these findings will impact HPAI project performances, and several guidelines are suggested.

  19. REVIVING ABANDONED RESERVOIRS WITH HIGH-PRESSURE AIR INJECTION: APPLICATION IN A FRACTURED AND KARSTED DOLOMITE RESERVOIR

    Energy Technology Data Exchange (ETDEWEB)

    Robert Loucks; Steve Ruppel; Julia Gale; Jon Holder; Jon Olsen; Deanna Combs; Dhiraj Dembla; Leonel Gomez

    2003-06-01

    The Bureau of Economic Geology and Goldrus Producing Company have assembled a multidisciplinary team of geoscientists and engineers to evaluate the applicability of high-pressure air injection (HPAI) in revitalizing a nearly abandoned carbonate reservoir in the Permian Basin of West Texas. The characterization phase of the project is utilizing geoscientists and petroleum engineers from the bureau of Economic Geology and the Department of Petroleum Engineering (both at The University of Texas at Austin) to define the controls on fluid flow in the reservoir as a basis for developing a reservoir model. This model will be used to define a field deployment plant that Goldrus, a small independent oil company, will implement by drilling both vertical and horizontal wells during the demonstration phase of the project. Additional reservoir data are being gathered during the demonstration phase to improve the accuracy of the reservoir model. The results of the demonstration are being closely monitored to provide a basis for improving the design of the HPAI field deployment plan. The results of the reservoir characterization field demonstration and monitoring program will be documented and widely disseminated to facilitate adoption of this technology by oil operators in the Permian Basin and elsewhere in the US.

  20. Simulation Analysis of Sludge Disposal and Volatile Fatty Acids Production from Gravity Pressure Reactor via Wet Air Oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Park, Gwon Woo [Biomass and Waste Energy Laboratory, KIER, Daejeon (Korea, Republic of); Seo, Tae Wan; Lee, Hong-Cheol; Hwang, In-Ju [Environmental and Plant Engineering Research Institute, KICT, Goyang (Korea, Republic of)

    2016-04-15

    Efficacious wastewater treatment is essential for increasing sewage sludge volume and implementing strict environmental regulations. The operation cost of sludge treatment amounts up to 50% of the total costs for wastewater treatment plants, therefore, an economical sludge destruction method is crucially needed. Amid several destruction methods, wet air oxidation (WAO) can efficiently treat wastewater containing organic pollutants. It can be used not only for sludge destruction but also for useful by-product production. Volatile fatty acids (VFAs), one of many byproducts, is considered to be an important precursor of biofuel and chemical materials. Its high reaction condition has instituted the study of gravity pressure reactor (GPR) for an economical process of WAO to reduce operation cost. Simulation of subcritical condition was conducted using Aspen Plus with predictive Soave-Redlich-Kwong (PSRK) equation of state. Conjointly, simulation analysis for GPR depth, oxidizer type, sludge flow rate and oxidizer injection position was carried out. At GPR depth of 1000m and flow rate of 2 ton/h, the conversion and yield of VFAs were 92.02% and 0.17g/g, respectively.

  1. Development of hydrophilic dental wax without surfactant using a non-thermal air atmospheric pressure plasma jet

    Science.gov (United States)

    Lee, Jung-Hwan; Kim, Yong-Hee; Choi, Eun-Ha; Kim, Kwang-Mahn; Kim, Kyoung-Nam

    2014-06-01

    Dental wax (DW), a low-melting and high-molecular-weight organic mixture, is widely used in dentistry for forming moulds of teeth. Hydrophilicity is an important property for DW, as a wet dental investment is used to surround the wax before wax burnout is performed. However, recent attempts to improve the hydrophilicity of DW using a surfactant have resulted in the reduced mechanical properties of the dental investment, leading to the failure of the dental restoration. This study applied a non-thermal air atmospheric pressure plasma jet (AAPPJ) for DW surface treatment and investigated its effect on both DW hydrophilicity and the dental investment's mechanical properties. The results showed that the application of the AAPPJ significantly improved the hydrophilicity of the DW, and that the results were similar to that of cleaner-treated DW using commercially available products with surfactant. A surface chemical analysis indicated that the improvement of hydrophilicity was related to an increase in the number of oxygen-related bonds on the DW surface following the removal of carbon hydrate in both AAPPJ and cleaner-treated DW. However, cleaner treatment compromised the mechanical property of the dental investment when the dental investment was in contact with the treated DW, while the AAPPJ treatment did not. Therefore, the use of AAPPJ to treat DW is a promising method for accurate dental restoration, as it induces an improvement in hydrophilicity without harming the dental investment.

  2. A comparison of ground and satellite observations of cloud cover to saturation pressure differences during a cold air outbreak

    Energy Technology Data Exchange (ETDEWEB)

    Alliss, R.J.; Raman, S. [North Carolina State Univ., Raleigh, NC (United States)

    1996-04-01

    The role of clouds in the atmospheric general circulation and the global climate is twofold. First, clouds owe their origin to large-scale dynamical forcing, radiative cooling in the atmosphere, and turbulent transfer at the surface. In addition, they provide one of the most important mechanisms for the vertical redistribution of momentum and sensible and latent heat for the large scale, and they influence the coupling between the atmosphere and the surface as well as the radiative and dynamical-hydrological balance. In existing diagnostic cloudiness parameterization schemes, relative humidity is the most frequently used variable for estimating total cloud amount or stratiform cloud amount. However, the prediction of relative humidity in general circulation models (GCMs) is usually poor. Even for the most comprehensive GCMs, the predicted relative humidity may deviate greatly from that observed, as far as the frequency distribution of relative humidity is concerned. Recently, there has been an increased effort to improve the representation of clouds and cloud-radiation feedback in GCMs, but the verification of cloudiness parameterization schemes remains a severe problem because of the lack of observational data sets. In this study, saturation pressure differences (as opposed to relative humidity) and satellite-derived cloud heights and amounts are compared with ground determinations of cloud cover over the Gulf Stream Locale (GSL) during a cold air outbreak.

  3. Experimental study on the flow regimes and pressure gradients of air-oil-water three-phase flow in horizontal pipes.

    Science.gov (United States)

    Al-Hadhrami, Luai M; Shaahid, S M; Tunde, Lukman O; Al-Sarkhi, A

    2014-01-01

    An experimental investigation has been carried out to study the flow regimes and pressure gradients of air-oil-water three-phase flows in 2.25 ID horizontal pipe at different flow conditions. The effects of water cuts, liquid and gas velocities on flow patterns and pressure gradients have been studied. The experiments have been conducted at 20 °C using low viscosity Safrasol D80 oil, tap water and air. Superficial water and oil velocities were varied from 0.3 m/s to 3 m/s and air velocity varied from 0.29 m/s to 52.5 m/s to cover wide range of flow patterns. The experiments were performed for 10% to 90% water cuts. The flow patterns were observed and recorded using high speed video camera while the pressure drops were measured using pressure transducers and U-tube manometers. The flow patterns show strong dependence on water fraction, gas velocities, and liquid velocities. The observed flow patterns are stratified (smooth and wavy), elongated bubble, slug, dispersed bubble, and annular flow patterns. The pressure gradients have been found to increase with the increase in gas flow rates. Also, for a given superficial gas velocity, the pressure gradients increased with the increase in the superficial liquid velocity. The pressure gradient first increases and then decreases with increasing water cut. In general, phase inversion was observed with increase in the water cut. The experimental results have been compared with the existing unified Model and a good agreement has been noticed.

  4. Experimental and numerical investigations of air plasmas induced by multi-MeV pulsed X-ray from low to atmospheric pressures

    Science.gov (United States)

    Maulois, Mélissa; Ribière, Maxime; Eichwald, Olivier; Yousfi, Mohammed; Pouzalgues, Romain; Garrigues, Alain; Delbos, Christophe; Azaïs, Bruno

    2016-09-01

    This research work is devoted to the experimental and theoretical analysis of air plasmas induced by multi-MeV pulsed X-ray for a large pressure range of humid air background gas varying from 20 mbar to atmospheric pressure. The time evolution of the electron density of the air plasma is determined by electromagnetic wave absorption measurements. The measurements have uncertainties of about ±30%, taking into account the precision of the dose measurement and also the shot to shot fluctuations of the generator. The experimental electron density is obtained by comparing the measurements of the transmitted microwave signals to the calculated ones. The calculations need the knowledge of the time evolution of the electron mean energy, which is determined by a chemical kinetic model based on a reaction scheme involving 39 species interacting following 265 reactions. During the X-ray pulse, a good agreement is obtained between time evolution of the electron density obtained from absorption measurements and calculations based on the kinetic model. The relative deviation on the maximum electron density and the corresponding plasma frequency is always lower than 10%. The maximum electron density varies from 4 × 1011 to 3.5 × 1013 cm-3 between 30 mbar to atmospheric pressure, while the peak of the electron mean energy decreases from 5.64 eV to 4.27 eV in the same pressure range.

  5. Modelling of heat and mass transfer in a granular medium during high-temperature air drying. Effect of the internal gas pressure

    Science.gov (United States)

    Othmani, Hammouda; Hassini, Lamine; Lamloumi, Raja; El Cafsi, Mohamed Afif

    2016-02-01

    A comprehensive internal heat and water transfer model including the gas pressure effect has been proposed in order to improve the industrial high-temperature air drying of inserts made of agglomerated sand. In this model, the internal gas phase pressure effect was made perfectly explicit, by considering the liquid and vapour transfer by filtration and the liquid expulsion at the surface. Wet sand enclosed in a tight cylindrical glass bottle dried convectively at a high temperature was chosen as an application case. The model was validated on the basis of the experimental average water content and core temperature curves for drying trials at different operating conditions. The simulations of the spatio-temporal distribution of internal gas pressure were performed and interpreted in terms of product potential damage. Based on a compromise between the drying time and the pressure increase, a simple drying cycle was implemented in order to optimize the drying process.

  6. Functionalization of graphene by atmospheric pressure plasma jet in air or H{sub 2}O{sub 2} environments

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Weixin [Radiation Laboratory, University of Notre Dame, Notre Dame, IN 46556 (United States); Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556 (United States); Ptasinska, Sylwia, E-mail: Sylwia.Ptasinska.1@nd.edu [Radiation Laboratory, University of Notre Dame, Notre Dame, IN 46556 (United States); Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States)

    2016-03-30

    Graphical abstract: - Highlights: • Facile plasma approach was used to functionalize graphene in air or in H{sub 2}O{sub 2} solution. • For the first time, observation of graphene reduction was observed in oxidative surrounding. • N-doping of graphene in H{sub 2}O{sub 2} solution occurred during the APPJ treatment. • H{sub 2}O{sub 2} solution acted as a buffer layer to prevent graphene etching. • Increase in resistance of the plasma-treated graphene was measured. • The transition of the material property from semi-metallic to semiconducting was revealed in the four-point probe measurement manifested by an increase in sheet resistance of the plasma-treated graphene. - Abstract: The functionalization of graphene, which deforms its band structure, can result in a metal-semiconductor transition. In this work, we report a facile strategy to oxidize single-layer graphene using an atmospheric pressure plasma jet (APPJ) that generates a variety of reactive plasma species at close to ambient temperature. We systematically characterized the oxygen content and chemical structure of the graphene films after plasma treatment under different oxidative conditions (ambient air atmosphere or hydrogen peroxide solution) by X-ray Photoelectron Spectroscopy (XPS). Plasma-treated graphene films containing more than 40% oxygen were obtained in both oxidative environments. Interestingly, prolonged irradiation led to the reduction of graphene oxides. N-doping of graphene also occurred during the APPJ treatment in H{sub 2}O{sub 2} solution; the nitrogen content of the doped graphene was dependent on the duration of irradiation and reached up to 8.1% within 40 min. Moreover, the H{sub 2}O{sub 2} solution served as a buffer layer that prevented damage to the graphene during plasma irradiation. Four-point probe measurement revealed an increase in sheet resistance of the plasma-treated graphene, indicating the transition of the material property from semi-metallic to semiconducting.

  7. Atmospheric Pressure Indicator.

    Science.gov (United States)

    Salzsieder, John C.

    1995-01-01

    Discusses observable phenomena related to air pressure. Describes a simple, unobtrusive, semiquantitative device to monitor the changes in air pressure that are associated with altitude, using a soft-drink bottle and a balloon. (JRH)

  8. A Remote Sensing Method for Estimating Surface Air Temperature and Surface Vapor Pressure on a Regional Scale

    Directory of Open Access Journals (Sweden)

    Renhua Zhang

    2015-05-01

    Full Text Available This paper presents a method of estimating regional distributions of surface air temperature (Ta and surface vapor pressure (ea, which uses remotely-sensed data and meteorological data as its inputs. The method takes into account the effects of both local driving force and horizontal advection on Ta and ea. Good correlation coefficients (R2 and root mean square error (RMSE between the measurements of Ta/ea at weather stations and Ta/ea estimates were obtained; with R2 of 0.77, 0.82 and 0.80 and RMSE of 0.42K, 0.35K and 0.20K for Ta and with R2 of 0.85, 0.88, 0.88 and RMSE of 0.24hpa, 0.35hpa and 0.16hpa for ea, respectively, for the three-day results. This result is much better than that estimated from the inverse distance weighted method (IDW. The performance of Ta/ea estimates at Dongping Lake illustrated that the method proposed in the paper also has good accuracy for a heterogeneous surface. The absolute biases of Ta and ea estimates at Dongping Lake from the proposed method are less than 0.5Kand 0.7hpa, respectively, while the absolute biases of them from the IDW method are more than 2K and 3hpa, respectively. Sensitivity analysis suggests that the Ta estimation method presented in the paper is most sensitive to surface temperature and that the ea estimation method is most sensitive to available energy.

  9. Changes in the electro-physical properties of MCT epitaxial films affected by a plasma volume discharge induced by an avalanche beam in atmospheric-pressure air

    Science.gov (United States)

    Grigoryev, D. V.; Voitsekhovskii, A. V.; Lozovoy, K. A.; Tarasenko, V. F.; Shulepov, M. A.

    2015-11-01

    In this paper the influence of the plasma volume discharge of nanosecond duration formed in a non-uniform electric field at atmospheric pressure on samples of epitaxial films HgCdTe (MCT) films are discussed. The experimental data show that the action of pulses of nanosecond volume discharge in air at atmospheric pressure leads to changes in the electrophysical properties of MCT epitaxial films due to formation of a near-surface high- conductivity layer of the n-type conduction. The preliminary results show that it is possible to use such actions in the development of technologies for the controlled change of the properties of MCT.

  10. Effect of Initial Moisture Content on the in-Vessel Composting Under Air Pressure of Organic Fraction of MunicipalSolid Waste in Morocco

    Directory of Open Access Journals (Sweden)

    Abdelhadi Makan

    2013-01-01

    Full Text Available This study aimed to evaluate the effect of initial moisture content on the in-vessel composting under air pressure of organic fraction of municipal solid waste in Morocco in terms of internal temperature, produced gases quantity, organic matter conversion rate, and the quality of the final composts.For this purpose, in-vessel bioreactor was designed and used to evaluate both appropriate initial air pressure and appropriate initial moisture content for the composting process. Moreover, 5 experiments were carried out within initial moisture content of 55%, 65%, 70%, 75% and 85%. The initial air pressure and the initial moisture content of the mixture showed a significant effect on the aerobic composting. The experimental results demonstrated that for composting organic waste, relatively high moisture contents are better at achieving higher temperatures and retaining them for longer times.This study suggested that an initial moisture content of around 75%, under 0.6 bar, can be considered as being suitable for efficient composting of organic fraction of municipal solid waste. These last conditions, allowed maximum value of temperature and final composting product with good physicochemical properties as well as higher organic matter degradation and higher gas production. Moreover, final compost obtained showed good maturity levels and can be used for agricultural applications.

  11. Effects of Atmospheric-Pressure N2, He, Air, and O2 Microplasmas on Mung Bean Seed Germination and Seedling Growth

    Science.gov (United States)

    Zhou, Renwu; Zhou, Rusen; Zhang, Xianhui; Zhuang, Jinxing; Yang, Size; Bazaka, Kateryna; (Ken) Ostrikov, Kostya

    2016-01-01

    Atmospheric-pressure N2, He, air, and O2 microplasma arrays have been used to investigate the effects of plasma treatment on seed germination and seedling growth of mung bean in aqueous solution. Seed germination and growth of mung bean were found to strongly depend on the feed gases used to generate plasma and plasma treatment time. Compared to the treatment with atmospheric-pressure O2, N2 and He microplasma arrays, treatment with air microplasma arrays was shown to be more efficient in improving both the seed germination rate and seedling growth, the effect attributed to solution acidification and interactions with plasma-generated reactive oxygen and nitrogen species. Acidic environment caused by air discharge in water may promote leathering of seed chaps, thus enhancing the germination rate of mung bean, and stimulating the growth of hypocotyl and radicle. The interactions between plasma-generated reactive species, such as hydrogen peroxide (H2O2) and nitrogen compounds, and seeds led to a significant acceleration of seed germination and an increase in seedling length of mung bean. Electrolyte leakage rate of mung bean seeds soaked in solution activated using air microplasma was the lowest, while the catalase activity of thus-treated mung bean seeds was the highest compared to other types of microplasma. PMID:27584560

  12. Effects of Atmospheric-Pressure N2, He, Air, and O2 Microplasmas on Mung Bean Seed Germination and Seedling Growth

    Science.gov (United States)

    Zhou, Renwu; Zhou, Rusen; Zhang, Xianhui; Zhuang, Jinxing; Yang, Size; Bazaka, Kateryna; (Ken) Ostrikov, Kostya

    2016-09-01

    Atmospheric-pressure N2, He, air, and O2 microplasma arrays have been used to investigate the effects of plasma treatment on seed germination and seedling growth of mung bean in aqueous solution. Seed germination and growth of mung bean were found to strongly depend on the feed gases used to generate plasma and plasma treatment time. Compared to the treatment with atmospheric-pressure O2, N2 and He microplasma arrays, treatment with air microplasma arrays was shown to be more efficient in improving both the seed germination rate and seedling growth, the effect attributed to solution acidification and interactions with plasma-generated reactive oxygen and nitrogen species. Acidic environment caused by air discharge in water may promote leathering of seed chaps, thus enhancing the germination rate of mung bean, and stimulating the growth of hypocotyl and radicle. The interactions between plasma-generated reactive species, such as hydrogen peroxide (H2O2) and nitrogen compounds, and seeds led to a significant acceleration of seed germination and an increase in seedling length of mung bean. Electrolyte leakage rate of mung bean seeds soaked in solution activated using air microplasma was the lowest, while the catalase activity of thus-treated mung bean seeds was the highest compared to other types of microplasma.

  13. Air/Liquid-pressure and heartbeat-driven flexible fiber nanogenerators as a micro/nano-power source or diagnostic sensor.

    Science.gov (United States)

    Li, Zetang; Wang, Zhong Lin

    2011-01-04

    We present a new approach for fabricating flexible fiber nanogenerators (FNGs) that can be used for smart shirts, flexible electronics, and medical applications. These FNGs are based on carbon fibers that are covered cylindrically by textured zinc oxide (ZnO) thin films. Once subjected to uni-compression by applying a pressure, the cylindrical ZnO thin film is under a compressive strain, resulting in a macroscopic piezopotential across its inner and exterior surfaces owing to the textured structure of the film, which is the driving force for generating an electric current in the external load. Using such a structure, an output peak voltage of 3.2 V and average current density of 0.15 μA cm(-2) are demonstrated. The FNGs rely on air pressure, so that it can work in a non-contact mode in cases of rotating tires, flowing air/liquid, and even in blood vessels. Pressure-driven FNGs added to a syringe show potential to harvest energy in blood vessels, gas pipes, and oil pipes, as long as there is a fluctuation in pressure (or turbulence). Heart-pulse driven FNGs can serve as ultrasensitive sensors for monitoring the behavior of the human heart, which may possibly be applied to medical diagnostics as sensors and measurement tools.

  14. Observations of the 18.6-year cycle of air pressure and a theoretical model to explain certain aspects of this signal

    Science.gov (United States)

    O'Brien, D. P.; Currie, R. G.

    1993-07-01

    Evidence from barometric data in Japan, USSR, southern Europe, southern Africa, and South America shows that air pressure variations with period near 18.6-years can attain amplitudes as high as 0.9 mb, and are identified as induced by the luni-solar constituent tide M n (M for moon and n for nodal). Luni-solar waveforms commonly exhibit modulation effects due to the superposition of a longer period component with 180° changes in phase. Thus, the waveform amplitudes can be highly nonstationary. Pressure gradients at this period over subcontinental distances show that the amplitudes imply nonequilibrium conditions. A theoretical coupling mechanism between E-W and N-S wind systems and the Coriolis force is envoked to explain the sub-continental extent and the, sometimes abrupt, amplitude changes of the pressure systems over small distances.

  15. Reviving Abandoned Reservoirs with High-Pressure Air Injection: Application in a Fractured and Karsted Dolomite Reservoir

    Energy Technology Data Exchange (ETDEWEB)

    Robert Loucks; Stephen C. Ruppel; Dembla Dhiraj; Julia Gale; Jon Holder; Jeff Kane; Jon Olson; John A. Jackson; Katherine G. Jackson

    2006-09-30

    Despite declining production rates, existing reservoirs in the United States contain vast volumes of remaining oil that is not being effectively recovered. This oil resource constitutes a huge target for the development and application of modern, cost-effective technologies for producing oil. Chief among the barriers to the recovery of this oil are the high costs of designing and implementing conventional advanced recovery technologies in these mature, in many cases pressure-depleted, reservoirs. An additional, increasingly significant barrier is the lack of vital technical expertise necessary for the application of these technologies. This lack of expertise is especially notable among the small operators and independents that operate many of these mature, yet oil-rich, reservoirs. We addressed these barriers to more effective oil recovery by developing, testing, applying, and documenting an innovative technology that can be used by even the smallest operator to significantly increase the flow of oil from mature U.S. reservoirs. The Bureau of Economic Geology and Goldrus Producing Company assembled a multidisciplinary team of geoscientists and engineers to evaluate the applicability of high-pressure air injection (HPAI) in revitalizing a nearly abandoned carbonate reservoir in the Permian Basin of West Texas. The Permian Basin, the largest oil-bearing basin in North America, contains more than 70 billion barrels of remaining oil in place and is an ideal venue to validate this technology. We have demonstrated the potential of HPAI for oil-recovery improvement in preliminary laboratory tests and a reservoir pilot project. To more completely test the technology, this project emphasized detailed characterization of reservoir properties, which were integrated to access the effectiveness and economics of HPAI. The characterization phase of the project utilized geoscientists and petroleum engineers from the Bureau of Economic Geology and the Department of Petroleum

  16. The Production and Evolution of Atomic Oxygen in the Afterglow of Streamer Discharge in Atmospheric Pressure Fuel/Air Mixtures

    Science.gov (United States)

    2013-07-02

    OH where the C3H7 radical can be formed in two isomeric configurations with total rate coefficient k ~ 3 x 1011 cm3 s-1 at T = 1500 K [14, 18]. At...in air and air/fuel nanosecond pulse dillcharges by two photon laser induced fluorescence Proc. Combust. lnst. 32 929 -36 [10] Bowman S, Adamovich

  17. Measurement of vibrationally excited N2(v) in an atmospheric-pressure air pulsed corona discharge using coherent anti-Stokes Raman scattering

    Science.gov (United States)

    Teramoto, Yoshiyuki; Ono, Ryo

    2014-08-01

    Vibrationally excited N2(v = 1, 2) in an atmospheric-pressure air pulsed corona discharge was measured using coherent anti-Stokes Raman scattering (CARS). In a dry air discharge, the vibrational temperature determined from the ratio N2(v = 2)/N2(v = 0), Tv2, was approximately 500 K higher than that determined from N2(v = 1)/N2(v = 0), Tv1, immediately after the discharge pulse. Both vibrational temperatures reached equilibrium within 100 μs after the discharge pulse by the vibration-to-vibration (V-V) process of N2-N2. The translational temperature was also measured using CARS. The rise in the translational temperature due to vibration-to-translation (V-T) energy transfer was not observed for a postdischarge time of 5 μs-1 ms in the dry-air discharge. However, when the air was humidified, a significant V-T energy transfer was observed. It was due to an extremely rapid V-T process of H2O-H2O following the V-V process of N2-H2O. Measurements showed that the humidification of the ambient air accelerated the decrease in the N2 vibrational temperature and increased the translational temperature. N2(v) was generated mostly in the secondary streamer, not in the primary one, according to estimation from the measured N2(v) density.

  18. Estimation of the in-cylinder air/fuel ratio of an internal combustion engine by the use of pressure sensors

    Energy Technology Data Exchange (ETDEWEB)

    Tunestaal, Per

    2000-03-01

    This thesis investigates the use of cylinder pressure measurements for estimation of the in-cylinder air/fuel ratio in a spark ignited internal combustion engine. An estimation model which uses the net heat release profile for estimating the cylinder air/fuel ratio of a spark ignition engine is developed. The net heat release profile is computed from the cylinder pressure trace and quantifies the conversion of chemical energy of the reactants in the charge into thermal energy. The net heat release profile does not take heat- or mass transfer into account. Cycle-averaged air/fuel ratio estimates over a range of engine speeds and loads show an RMS error of 4.1% compared to measurements in the exhaust. A thermochemical model of the combustion process in an internal combustion engine is developed. It uses a simple chemical combustion reaction, polynominal fits of internal energy as function of temperature, and the first law of thermodynamics to derive a relationship between measured cylinder pressure and the progress of the combustion process. Simplifying assumptions are made to arrive at an equation which relates the net heat release to the cylinder pressure. Two methods for estimating the sensor offset of a cylinder pressure transducer are developed. Both methods fit the pressure data during the pre-combustion phase of the compression stroke to a polytropic curve. The first method assumes a known polytropic exponent, and the other estimates the polytropic exponent. The first method results in a linear least-squares problem, and the second method results in a nonlinear least-squares problem. The nonlinear least-squares problem is solved by separating out the nonlinear dependence and solving the single-variable minimization problem. For this, a finite difference Newton method is derived. Using this method, the cost of solving the nonlinear least-squares problem is only slightly higher than solving the linear least-squares problem. Both methods show good statistical

  19. Positive association between short-term ambient air pollution exposure and children blood pressure in China-Result from the Seven Northeast Cities (SNEC) study.

    Science.gov (United States)

    Zeng, Xiao-Wen; Qian, Zhengmin Min; Vaughn, Michael G; Nelson, Erik J; Dharmage, Shyamali C; Bowatte, Gayan; Perret, Jennifer; Chen, Duo-Hong; Ma, Huimin; Lin, Shao; de Foy, Benjamin; Hu, Li-Wen; Yang, Bo-Yi; Xu, Shu-Li; Zhang, Chuan; Tian, Yan-Peng; Nian, Min; Wang, Jia; Xiao, Xiang; Bao, Wen-Wen; Zhang, Ya-Zhi; Dong, Guang-Hui

    2017-05-01

    The impact of ambient air pollution on health causes concerns in China. However, little is known about the association of short-term air pollution exposure with blood pressure (BP) in children. The goal of present study was to assess the association between short-term air pollution and BP in children from a highly polluted area in China. This study enrolled 9354 children in 24 elementary and middle schools (aged 5-17 years) from the Seven Northeast Cities (SNEC) study, respectively, during the period of 2012-2013. Ambient air pollutants, including particulate matter with an aerodynamic diameter of ≤10 μm (PM10), sulfur dioxide (SO2), nitrogen dioxide (NO2) and ozone (O3) on the days (1-5 days) preceding BP examination were collected from local air monitoring stations. Generalized additive models and two-level regression analyses were used to evaluate the relationship between air pollution and BP after adjusting for other covariates. Results showed that with an interquartile range (IQR) increase in PM10 (50.0 μg/m(3)) and O3 (53.0 μg/m(3)) level during the 5-day mean exposure, positive associations with elevated BP were observed, with an odds ratio of 2.17 (95% CI, 1.61-2.93) for PM10 and 2.77 (95% CI, 1.94-3.95) for O3. Both systolic BP and diastolic BP levels were positively associated with an IQR increase of four air pollutants at different lag times. Specifically, an IQR increase in the 5-day mean of PM10 and O3 was associated with elevation of 2.07 mmHg (95% CI, 1.71-2.44) and 3.29 mmHg (95% CI, 2.86-3.72) in systolic BP, respectively. When stratified by sex, positive relationships were observed for elevated BP with NO2 exposure only in males. This is the first report on the relationship between ambient short-term air pollution exposure and children BP in China. Findings indicate a need to control air pollutants and protect children from heavy air pollution exposure in China.

  20. 变频均压防灭火控制系统的设计%System of Air Pressure Balance for Fire Control Based on Frequency Converter

    Institute of Scientific and Technical Information of China (English)

    蒋德智

    2013-01-01

      本文介绍了基于变频调速技术的矿井局扇风机控制系统的设计,该系统根据均压通风原理,通过传感器测量巷道进出风速、进风风门内外压差、一氧化碳浓等物理量,进行PID运算,调节变频器输出频率从而调节风机转速,实现风压和风量的动态平衡控制,在满足工作面正常通风的前提下,最大程度地减小采空区的漏风量,从而达到防灭火的目的。同时系统具有一氧化碳报警功能,当工作面发生起火现象时能够及时报警并采取相应的通风策略,减小或避免煤矿井下发生火险的可能性。%In this paper we introduced a design of pressure balance for air control system based on variable-frequency driver.This system is designed according to pressure balance for air theory,adjust the output frequency of VFD to regulate the motor speed,so we can realize the dynamic balance control of the air pressure and air quantity.The PID operation is based on the value of the wind speed sensor,air pressure sensor,CO concentration sensor.Under the premise of normal wind providing,we can reduce the catching fire possibility of mined-out area.Simultaneously,the system possesses the function of CO alarm,when the mined-out area is catching fire,system can generate a warning sign and take proper ventilation measure.

  1. Changes in foot pressure elicited by 3D air balance exercise and pelvic stability exercise for functional leg-length discrepancy in adult women.

    Science.gov (United States)

    Lee, Byung-Hoon; Kim, Jeong-Ja; Kim, Chan-Kyu

    2015-03-01

    [Purpose] This study was conducted to examine the effect of pelvic stabilization exercise and 3D equipment exercise on adult women with Functional Leg-Length Discrepancy (FLLD). [Subjects and Methods] Twenty female students in their 20's having FLLD without Structural Leg Length Discrepancy were selected. Exercise was performed for 50 min per session, three times a week, for six weeks. The Pelvic stabilization exercise (PSE) group performed pelvic stabilization exercises for 50 minutes, and the 3D exercise (3DE) group performed 3D Air Balance exercise for 10 minutes after performing the pelvic stabilization exercise program for 40 minutes. [Results] The PSE group showed statistically significant differences in tape measure method (TMM) and maximum pressure between pre-test and post-test, and 3DE showed statistically significant differences in TMM, the difference in maximum pressure, the difference in average pressure, and the difference in support area. At the end of the 6-week intervention, TMM, difference in maximum pressure, difference in average pressure, and difference in support area showed significantly greater reduction in the 3DE group. [Conclusion] The results show that 3D stabilization exercise was more effective at improving the stabilization of the deep muscles surrounding the pelvis and left-right muscular balance. We consider that 3D exercise should be included in exercise programs for improving pelvic cavity and spinal stability in the future.

  2. Air/delta/sea surface temperature, pressure, and other data from MISS GAIL in a world-wide distribution from 21 October 1957 to 18 April 1961 (NODC Accession 0000366)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Air/delta/sea surface temperature, pressure, and other data were collected from the MISS GAIL in a world-wide distribution from October 21, 1957 to April 18, 1961....

  3. Dynamics of ionization processes in high-pressure nitrogen, air, and SF{sub 6} during a subnanosecond breakdown initiated by runaway electrons

    Energy Technology Data Exchange (ETDEWEB)

    Tarasenko, V. F., E-mail: vft@loi.hcei.tsc.ru; Beloplotov, D. V.; Lomaev, M. I. [Siberian Branch, Russian Academy of Sciences, Institute of High-Current Electronics (Russian Federation)

    2015-10-15

    The dynamics of ionization processes in high-pressure nitrogen, air, and SF{sub 6} during breakdown of a gap with a nonuniform distribution of the electric field by nanosecond high-voltage pulses was studied experimentally. Measurements of the amplitude and temporal characteristics of a diffuse discharge and its radiation with a subnanosecond time resolution have shown that, at any polarity of the electrode with a small curvature radius, breakdown of the gap occurs via two ionization waves, the first of which is initiated by runaway electrons. For a voltage pulse with an ∼500-ps front, UV radiation from different zones of a diffuse discharge is measured with a subnanosecond time resolution. It is shown that the propagation velocity of the first ionization wave increases after its front has passed one-half of the gap, as well as when the pressure in the discharge chamber is reduced and/or when SF{sub 6} is replaced with air or nitrogen. It is found that, at nitrogen pressures of 0.4 and 0.7 MPa and the positive polarity of the high-voltage electrode with a small curvature radius, the ionization wave forms with a larger (∼30 ps) time delay with respect to applying the voltage pulse to the gap than at the negative polarity. The velocity of the second ionization wave propagating from the plane electrode is measured. In a discharge in nitrogen at a pressure of 0.7 MPa, this velocity is found to be ∼10 cm/ns. It is shown that, as the nitrogen pressure increases to 0.7 MPa, the propagation velocity of the front of the first ionization wave at the positive polarity of the electrode with a small curvature radius becomes lower than that at the negative polarity.

  4. ON THE FLYING SAFETY ASSOCIATED WITH THE AIR TEMPERATURE AND PRESSURE%气温、气压对飞行安全的影响分析

    Institute of Scientific and Technical Information of China (English)

    王永忠

    2001-01-01

    The errors of the airplane altimeter induced by the air temperature and pressure changes as well as the errors of speedometer induced by the air temperature change are analyzed in the present article. The results suggests that the constitution, in which the altitudes for different airlines are given abided by the civil aviation department should be improved. Some schemes are put forward in this paper.%分析了气温、气压变化造成的高度表误差及气温的变化带来的飞机空速表误差,认为现行民航航线飞行安全高度的规定存在一定的不足,并提出了改进办法。

  5. Surface Treatment of Polypropylene Films Using Homogeneous DBD Plasma at Atmospheric Pressure in Air%Surface Treatment of Polypropylene Films Using Homogeneous DBD Plasma at Atmospheric Pressure in Air

    Institute of Scientific and Technical Information of China (English)

    FANG Zhi; CAI Ling-ling; LEI Xiao; QIU Yu-chang; Kuffel Edmund

    2011-01-01

    The homogeneous dielectric barrier discharge (DBD) in atmospheric air is most favorable for polymer sur- face modification due to the low cost of operation and the ability of ambient on-line continuous uniform processing. In this paper, polypropylene (PP) films are treated using a homogeneous DBD plasma in atmospheric air. The surface properties of PP films are studied using contact angle and surface energy measurement, scanning electron microscopy (SEM) and Fourier trailsformed infrared spectroscopy (FTIR), and the aging effect after treatment when the treated materials are exposed to open air is also studied, with the modification mechanism being discussed. It is demonstrated that non thermal plasmas generated by homogeneous DBD in atmospheric air is an effective way to enhance the surface properties of PP films. After the pIasma treatment, the surface of PP film is etched, and oxygen-containing polar groups are introduced into the surface. These two processes can induce a remarkable decrease in water contact angle and a remarkable increase in surface energy, and the surface properties of PP films are improved accordingly.

  6. OH concentration in an atmospheric-pressure methane-air flame from molecular-beam mass spectrometry and laser-absorption spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Cattolica, R.J.; Yoon, S.; Knuth, E.L.

    1982-01-01

    In evaluating experimental techniques for studying premixed atmospheric-pressure methane-air flames, analysts demonstrated that the molecular-beam mass-spectrometry technique adequately measures OH concentration, given careful design of the sampling probe and appropriate consideration for possible mass interferences. Perturbation of the OH concentration profile using various sampling probes indicates the importance of minimizing the length of the sampling-orifice channel to reduce composition relaxation during sampling. The accuracy of the MBMS method was determined by comparing the results with those from a laser-absorption spectroscopy system.

  7. Key insights into the reacting kinetics of atmospheric pressure plasmas using He +N2 /O2 /CO2 /H2 O/Air mixtures

    Science.gov (United States)

    Murakami, Tomoyuki

    2015-09-01

    A zero dimensional kinetic chemistry computational modeling to identify the important collisional mechanisms and the dominant species in atmospheric pressure plasmas has been developed. This modeling provides an enhanced capability to tailor wide variety of reactive intermediates/species in atmospheric pressure plasmas using He +N2 /O2 /CO2 /H2 O/Air mixtures. The influence of the gas constituent, the gas temperature and the excitation frequency (kHz-, RF-, Pulsed-working) on the complex reacting chemical kinetics is clarified. This work also focuses on the benchmarking between the predictive outputs of this computer-based simulations and the diverse experimental diagnostics with particular emphasis on reactive oxygen/nitrogen intermediates/species. This work was partly supported by KAKENHI Grant Number 24561054.

  8. Boost Pressure Control Strategy to Account for Transient Behavior and Pumping Losses in a Two-Stage Turbocharged Air Path Concept

    Directory of Open Access Journals (Sweden)

    Thivaharan Albin

    2016-07-01

    Full Text Available Increasingly complex air path concepts are investigated to achieve a substantial reduction in fuel consumption while improving the vehicle dynamics. One promising technology is the two-stage turbocharging for gasoline engines, where a high pressure and a low pressure turbocharger are placed in series. For exploiting the high potential, a control concept has to be developed that allows for coordinated management of the two turbocharger stages. In this paper, the control strategy is investigated. Therefore, the effect of the actuated values on transient response and pumping losses is analyzed. Based on these findings, an optimization-based control algorithm is developed that allows taking both requirements into account. The developed new controller allows achieving a fast transient response, while at the same time reducing pumping losses in stationary operation.

  9. Clinical evaluation of an air-capsule technique for the direct measurement of intra-abdominal pressure after elective abdominal surgery

    Science.gov (United States)

    Otto, Jens; Kaemmer, Daniel; Biermann, Andreas; Jansen, Marc; Dembinski, Rolf; Schumpelick, Volker; Schachtrupp, Alexander

    2008-01-01

    Background The gold standard for assessment of intraabdominal pressure (IAP) is via intravesicular pressure measurement (IVP). This accepted technique has some inherent problems, e.g. indirectness. Aim of this clinical study was to assess direct IAP measurement using an air-capsule method (ACM) regarding complications risks and agreement with IVP in patients undergoing abdominal surgery. Methods A prospective cohort study was performed in 30 patients undergoing elective colonic, hepatic, pancreatic and esophageal resection. For ACM a Probe 3 (Spiegelberg®, Germany) was placed on the greater omentum. It was passed through the abdominal wall paralleling routine drainages. To compare ACM with IVP t-testing was performed and mean difference as well as limits of agreement were calculated. Results ACM did not lead to complications particularly with regard to organ lesion or surgical site infection. Mean insertion time of ACM was 4.4 days (min-max: 1–5 days). 168 pairwise measurements were made. Mean ACM value was 7.9 ± 2.7 mmHg while mean IVP was 8.4 ± 3.0 mmHg (n.s). Mean difference was 0.4 mmHg ± 2.2 mmHg. Limits of agreement were -4.1 mmHg to 5.1 mmHg. Conclusion Using ACM, direct IAP measurement is feasible and uncomplicated. Associated with relatively low pressure ranges (<17 mmHg), results are comparable to bladder pressure measurement. PMID:18925973

  10. Cold-air atmospheric pressure plasma against Clostridium difficile spores: a potential alternative for the decontamination of hospital inanimate surfaces.

    Science.gov (United States)

    Claro, Tânia; Cahill, Orla J; O'Connor, Niall; Daniels, Stephen; Humphreys, Hilary

    2015-06-01

    Clostridium difficile spores survive for months on environmental surfaces and are highly resistant to decontamination. We evaluated the effect of cold-air plasma against C. difficile spores. The single-jet had no effect while the multi-jet achieved 2-3 log10 reductions in spore counts and may augment traditional decontamination.

  11. 大气压空气介质阻挡汤森放电%Townsend Dielectric Barrier Discharge in Atmospheric Pressure Air

    Institute of Scientific and Technical Information of China (English)

    罗海云; 冉俊霞; 王新新

    2012-01-01

    In order to experimentally study the possibility of homogenous dielectric barrier discharge (DBD) in atmospheric pressure air as well as its characteristics, the homogenous DBD in 3 mm air gap was obtained at atmospheric pressure, using 1-2 kHz sinusoidal high voltage and no less than 1. 5 mm thick alumina as the dielectrics. The discharge was proven as an atmospheric pressure Townsend discharge after analyzing the 10 ns exposure high-speed photographs and the current waveform. The steady breakdown voltage for 3 mm air DBD was calculated to be about 5. 7 kV, much lower than 11. 2 kV, the static breakdown voltage of 3 mm air gap; Extraordinary extinction was also observed in air just like in nitrogen. Both the two phenomena indicated the existence of the shallow traps and consequently the second-electron emissidn in the alumina surface, which were important for ignition and maintaining stage of Townsend DBD. It is found that the thickness of alumina is important for air DBD, and the thickness less than 1.5 mm can not avoid the filamentary discharge. If two 1 mm thick quartz plates are used instead of alumina, it is impossible to get homogenous DBD at 670 PaN 0. 1 MPa in air. The mechanism of Townsend DBD in 3 mm air gap is attributed to the combined effects of the unique shallow traps in the alumina surface and the current-limitation of the dielectrics.%为了实验研究大气压空气介质阻挡均匀放电的可能性,使用1.5mm以上厚度的A120s陶瓷片作为阻挡介质及1-2kHz的高压激励,在大气压3mm空气平板间隙中获得均匀放电。通过ICCD高速摄影得到的放电图像以及电流波形的分析表明这种放电是汤森放电。3mm空气间隙的稳态击穿电压仅约为5.7kV,远低于静态击穿电压11.2kv;还发现了类似氮气DBD汤森放电的“反常熄灭”现象,这两个现象表明陶瓷表面可能存在浅位阱及二次电子发射机制,这对空气汤森放电的起始和维持阶段都

  12. Application of Air Pressure Transmission in Contest Robot%气压传动技术在竞赛机器人中的应用

    Institute of Scientific and Technical Information of China (English)

    王文涛

    2009-01-01

    With the development of robot contest,as a convenient and practical technique, air pressure transmission technology has penetrated into the contest and become an indispensable one. This paper draws a conclusion for the air pressure transmission scheme of Dalian university's robots which took part in the ABU robot contest of 2005. This scheme is easy to operate and can finish the taskefficiently.%近几年来随着机器人比赛的兴起,气压传动技术作为一种方便、实用的技术迅速地渗透到里面,成为了一种不可或缺的技术.本文对大连大学参加2005年亚太地区大学生机器人大赛的机器人做了气压传动设计方案的总结.本设计便于进行操作,并且能够最高效地完成动作.

  13. Flow pattern, void fraction and pressure drop of two-phase air-water flow in a horizontal circular micro-channel

    Energy Technology Data Exchange (ETDEWEB)

    Saisorn, Sira [Energy Division, The Joint Graduate School of Energy and Environment (JGSEE), King Mongkut' s University of Technology Thonburi, Bangmod, Bangkok 10140 (Thailand); Wongwises, Somchai [Fluid Mechanics, Thermal Engineering and Multiphase Flow Research Laboratory (FUTURE), Department of Mechanical Engineering, King Mongkut' s University of Technology Thonburi, Bangmod, Bangkok 10140 (Thailand)

    2008-01-15

    Adiabatic two-phase air-water flow characteristics, including the two-phase flow pattern as well as the void fraction and two-phase frictional pressure drop, in a circular micro-channel are experimentally studied. A fused silica channel, 320 mm long, with an inside diameter of 0.53 mm is used as the test section. The test runs are done at superficial velocity of gas and liquid ranging between 0.37-16 and 0.005-3.04 m/s, respectively. The flow pattern map is developed from the observed flow patterns i.e. slug flow, throat-annular flow, churn flow and annular-rivulet flow. The flow pattern map is compared with those of other researchers obtained from different working fluids. The present single-phase experiments also show that there are no significant differences in the data from the use of air or nitrogen gas, and water or de-ionized water. The void fraction data obtained by image analysis tends to correspond with the homogeneous flow model. The two-phase pressure drops are also used to calculate the frictional multiplier. The multiplier data show a dependence on flow pattern as well as mass flux. A new correlation of two-phase frictional multiplier is also proposed for practical application. (author)

  14. Study on Collection Efficiency and Pressure Drop of Pleated Air Filters%褶型空气滤清器捕集效率及压力损失

    Institute of Scientific and Technical Information of China (English)

    付海明; 尹峰

    2009-01-01

    For pressure drop reduction and collecting efficiency incretion of the air filter,using computational fluid dynamics (CFD) simulation technology and combineing with the way of experimental test,particles trajectories and distribution rate of deposition in air filters were calculated simulatively,the position where the particles reside easily was obtained.According to experimental data of collecting efficiency,multi-relation calculation formula of filtration media collecting efficiency was proposed.By building 2D and 3D model of CFD,flow field distribution and filtration pressure drop of air filters were simulated,the results of computer simulation were in agreement with experimental test results basically.Using simulation model and changing structural parameters of air filters to instead parts of experimental research,variation and formula of relationship between the filtration pressure drop and its significant single-factor impact of air filters were obtained.Based on a large number of simulation data,multi-relation calculation formula of relationship between the pressure drop and its structural parameters of air filters was proposed using regression analysis.%为提高空气滤清器的减阻增效,采用计算流体力学(CFD)模拟技术,结合实验测试的方法,模拟计算颗粒在空气滤清器中的运动轨迹和颗粒在滤清器中沉积的分布率,得出颗粒在滤清器中容易沉积的部位.根据捕集效率实验数据,提出过滤介质捕集效率的多元关联计算式.通过建立二维及三维的CFD模型,模拟计算空气滤清器的流场分布和过滤压力损失,其计算机模拟结果与实验测试结果基本吻合.利用已建立的模拟模型,改变空气滤清器结构参数,替代部分实验模拟研究,得出空气滤清器的过滤压力损失与其各自影响因素的变化规律,以及空气滤清器过滤压力损失与其主要影响因素的单因素关联式.利用大量的模拟数据,回归分析提出空

  15. An experimental study of constant-pressure steam injection and transient condensing flow in an air-saturated porous medium

    NARCIS (Netherlands)

    Brouwers, H.J.H.

    1996-01-01

    In this paper the unsteady process of constant pressure steam injection into an air–saturated porous medium is studied experimentally. To this end, vertical glass tubes are packed with dry quartz sand and injected with dry steam. The propagation of the steam front appears to be proportional to t. It

  16. A numerical study of the the response of transient inhomogeneous flames to pressure fluctuations and negative stretch in contracting hydrogen/air flames

    CERN Document Server

    Malik, Nadeem A; Lovas, Terese

    2016-01-01

    Transient premixed hydrogen/air flames contracting through inhomogeneous fuel distributions and subjected to stretch and pressure oscillations are investigated numerically using an implicit method which couples the fully compressible flow to the realistic chemistry and multicomponent transport properties. The impact of increasing {\\em negative} stretch is investigated through the use of planar, cylindrical and spherical geometries, and a comparison with the results from {\\em positively} stretched expanding H2/air flames (MALIK2010) and CH4/air flames (MALIK2012a) is made. A flame relaxation number $n_R=\\tau_R/\\tau_L$ ($\\tau_R$ is the time that the flame takes to return to the mean equilibrium conditions after initial disturbance; $\\tau_L$ is a flame time scale) decreases by 10\\% with increasing {\\em negative} stretch, in contrast to the two expanding flames where $n_R$ decreased by 40\\% with increasing {\\em positive} stretch. $n_R$ appears to much more sensitive to variations in positive/negative curvature th...

  17. Measuring combined exposure to environmental pressures in urban areas: an air quality and noise pollution assessment approach.

    Science.gov (United States)

    Vlachokostas, Ch; Achillas, Ch; Michailidou, A V; Moussiopoulos, Nu

    2012-02-01

    This study presents a methodological scheme developed to provide a combined air and noise pollution exposure assessment based on measurements from personal portable monitors. Provided that air and noise pollution are considered in a co-exposure approach, they represent a significant environmental hazard to public health. The methodology is demonstrated for the city of Thessaloniki, Greece. The results of an extensive field campaign are presented and the variations in personal exposure between modes of transport, routes, streets and transport microenvironments are evaluated. Air pollution and noise measurements were performed simultaneously along several commuting routes, during the morning and evening rush hours. Combined exposure to environmental pollutants is highlighted based on the Combined Exposure Factor (CEF) and Combined Dose and Exposure Factor (CDEF). The CDEF takes into account the potential relative uptake of each pollutant by considering the physical activities of each citizen. Rather than viewing environmental pollutants separately for planning and environmental sustainability considerations, the possibility of an easy-to-comprehend co-exposure approach based on these two indices is demonstrated. Furthermore, they provide for the first time a combined exposure assessment to these environmental pollutants for Thessaloniki and in this sense they could be of importance for local public authorities and decision makers. A considerable environmental burden for the citizens of Thessaloniki, especially for VOCs and noise pollution levels is observed. The material herein points out the importance of measuring public health stressors and the necessity of considering urban environmental pollution in a holistic way.

  18. Effects of Atmospheric Pressure Air Plasma Pretreatment on the Seed Germination and Early Growth of Andrographis paniculata

    Science.gov (United States)

    Tong, Jiayun; He, Rui; Zhang, Xiaoli; Zhan, Ruoting; Chen, Weiwen; Yang, Size

    2014-03-01

    The objective of this paper is to demonstrate whether air plasma can change the seed germination characteristics, seedling emergence, as well as biochemical reactivity, in Andrographis paniculata (A. paniculata) seedlings by modifying the seed coat and finding a beneficial treatment dose. Eight treatment doses and one control were used to conduct electrical conductivity determination, a germination test, a seedling emergence test and a biochemical assay. The results showed that after being treated with air plasma excited at 5950 V for 10 s, the permeability of the seeds was improved significantly, resulting in the acceleration of seed germination and seedling emergence. In the meantime, the catalase activity and catalase isoenzyme expression were also improved, while the malondialdehyde content in the seedlings was decreased (which means greater counteraction with environmental stress). After being treated with 4250 V for 10 s and 5950 V for 20 s, the seed germination was enhanced, but without an obvious change in seedling emergence. However, after treatment with 3400 V for 20 s and 5100 V for 10 s, the permeability of the seeds was decreased, resulting in a delay in seedling emergence. These results indicate that air plasma can change the physiological and biochemical characteristics of Andrographis paniculata seeds by modifying the seed coat, combined with the effects of the active plasma species, and that different treating doses have different effects.

  19. Study of air entrainment in high pressure spray: optics diagnostics and application to the Diesel injection; Etude de l'entrainement d'air dans un spray haute pression: diagnostics optiques et application a l'injection diesel

    Energy Technology Data Exchange (ETDEWEB)

    Arbeau, A.

    2004-12-15

    The actual development of the engine must reply to a will of fuel consumption reduction and to norms more and more strict concerning the pollutant emissions. Although the Diesel engines are efficient, the NO{sub x} and particle emissions mainly come from the existence of wealthy fuel zone preventing an optimal combustion. Therefore, the air / fuel mixing preparation, highly controlled by the air entrainment in spray, is essential. In this context, we have developed metrological tools in order to analyse the air entrainment mechanism in a dense spray. The Particle Image Velocimetry (PIV) technique is first applied to a conical spray with an injection pressure less than 100 bars to study the air entrainment in spray. A transfer of the methodologies allows then the characterisation and the understanding of the air entrainment mechanism in high pressure full spray (injection pressure less than 1600 bars) type Diesel one. The influence of injection parameters (injection pressure and back pressure) on the mixing rate is studied. The increase of the injection pressure from 800 to 1600 bars implies an increase of the mixing rate of 60 %. Moreover, the thermodynamic conditions of the ambient air, simulated by the chamber back pressure, widely favours the mixing rate. Actually, this latter increases of 350 % when the chamber back pressure varies from 1 to 7 bars. The experimental results do not follow classical laws of air entrainment in one-phase flow jet with variable density, but are in good agreement with an integral model for air entrainment in an axisymmetric full spray. Finally, the Fluorescence Particle Image Velocimetry (FPIV) is introduced in order to extend the PIV application field in dense two-phase flows. (author)

  20. Clinical evaluation of an air-capsule technique for the direct measurement of intra-abdominal pressure after elective abdominal surgery

    Directory of Open Access Journals (Sweden)

    Dembinski Rolf

    2008-10-01

    Full Text Available Abstract Background The gold standard for assessment of intraabdominal pressure (IAP is via intravesicular pressure measurement (IVP. This accepted technique has some inherent problems, e.g. indirectness. Aim of this clinical study was to assess direct IAP measurement using an air-capsule method (ACM regarding complications risks and agreement with IVP in patients undergoing abdominal surgery. Methods A prospective cohort study was performed in 30 patients undergoing elective colonic, hepatic, pancreatic and esophageal resection. For ACM a Probe 3 (Spiegelberg®, Germany was placed on the greater omentum. It was passed through the abdominal wall paralleling routine drainages. To compare ACM with IVP t-testing was performed and mean difference as well as limits of agreement were calculated. Results ACM did not lead to complications particularly with regard to organ lesion or surgical site infection. Mean insertion time of ACM was 4.4 days (min-max: 1–5 days. 168 pairwise measurements were made. Mean ACM value was 7.9 ± 2.7 mmHg while mean IVP was 8.4 ± 3.0 mmHg (n.s. Mean difference was 0.4 mmHg ± 2.2 mmHg. Limits of agreement were -4.1 mmHg to 5.1 mmHg. Conclusion Using ACM, direct IAP measurement is feasible and uncomplicated. Associated with relatively low pressure ranges (

  1. Study on Flow Phenomenon inside a Nozzle in Ship Propulsion Equipment Directly Driven by High Pressure Air

    Science.gov (United States)

    Tajiri, Shinsuke; Tsutahara, Michihisa; Ogawa, Kazuhiko; Sakamoto, Masahiko; Tajima, Masakazu; Azuma, Keisuke

    An experimental study was conducted by performing pressure measurements and flow visualization to investigate unsteady flows inside a two-dimensional semi-open-type nozzle in a ship propulsion equipment directly driven by high-pressure gas. We found that the ejected gas phase and water-flow phase are separated clearly, and the interface between these phases behaves like waves. It was clarified by flow visualization with a high-speed motion camera and a circulating water channel that these interfacial waves change their shapes according to the water-flow velocity. The interfacial wavelength increases as a result of increasing water-flow velocity, and the mechanism that produces thrust on the nozzle wall changes. The thrust and flow patterns for intermittent gas ejection according to water-flow velocity were also clarified.

  2. Pressure distribution and aerodynamic coefficients associated with heat addition to supersonic air stream adjacent to two-dimensional supersonic wing

    Science.gov (United States)

    Pinkel, I Irving; Serafini, John S; Gregg, John L

    1952-01-01

    The modifications in the pressure distributions and the aerodynamic coefficients associated with additions of heat to the two-dimensional supersonic in viscid flow field adjacetnt to the lower surface of of a 5-percent-thickness symmetrical circular-arc wing are presented in this report. The pressure distributions are obtained by the use of graphical method which gives the two-dimensional supersonic inviscid flow field obtained with moderate heat addition. The variation is given of the lift-drag ratio and of the aerodynamic coefficients of lift, drag, and moment with free stream Mach number, angle of attack, and parameters defining extent and amount of heat addition. The six graphical solutions used in this study included Mach numbers of 3.0 and 5.0 and angles of attack of 0 degrees and 2 degrees.

  3. Cold atmospheric-pressure air plasma treatment of C6 glioma cells: effects of reactive oxygen species in the medium produced by the plasma on cell death

    Science.gov (United States)

    Yuyang, Wang; Cheng, Cheng; Peng, Gao; Shaopeng, Li; Jie, Shen; Yan, Lan; Yongqiang, Yu; Paul, K. Chu

    2017-02-01

    An atmospheric-pressure air plasma is employed to treat C6 glioma cells in vitro. To elucidate on the mechanism causing cell death and role of reactive species (RS) in the medium produced by the plasma, the concentration of the long-lived RS such as hydrogen peroxide, nitrate, and ozone in the plasma-treated liquid (phosphate-buffered saline solution) is measured. When vitamin C is added to the medium as a ROS quencher, the viability of C6 glioma cells after the plasma treatment is different from that without vitamin C. The results demonstrate that reactive oxygen species (ROS) such as H2O2, and O3 constitute the main factors for inactivation of C6 glioma cells and the reactive nitrogen species (RNS) may only play an auxiliary role in cell death.

  4. A tris(triazolate) ligand for a highly active and magnetically recoverable palladium catalyst of selective alcohol oxidation using air at atmospheric pressure.

    Science.gov (United States)

    Wang, Dong; Deraedt, Christophe; Salmon, Lionel; Labrugère, Christine; Etienne, Laetitia; Ruiz, Jaime; Astruc, Didier

    2015-04-20

    High efficiency and selectivity, easy magnetic recovery and recycling, and use of air as the oxidant at atmospheric pressure are major objectives for oxidation catalysis in terms of sustainable and green processes. A tris(triazolyl) ligand, so far only used in copper-catalyzed alkyne azide cycloadditions, was found to be extremely efficient in SiO2 /γ-Fe2 O3 -immobilized palladium complexes. It was characterized by inductively coupled plasma (ICP) analysis, transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectra (XPS) and found to fulfill the combined conditions for the selective oxidation of alcohols to aldehydes and ketones.

  5. OH concentration in an atmospheric-pressure methane-air flame from molecular-beam mass spectrometry and laser-absorption spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Cattolica, R.J.; Yoon, S.; Knuth, E.L.

    1980-12-01

    The concentration of the OH radical in a stoichiometric methane-air flat flame at atmospheric pressure was measured with both laser-absorption spectroscopy and molecular-beam mass spectrometry (MBMS). The nonequilibrium peak OH concentrations and the OH decay rate measured from the two techniques were in good agreement. The OH profile from the MBMS measurements, however, was shifted downstream from the absorption measurements by approximately 5 times the sampling-orifice diameter. A comparison of temperature profiles from thermocouple measurements and from a molecular-beam time-of-flight technique exhibited a similar downstream shift. The MBMS measurements effectively sampled the gas properties approximately five orifice diameters ahead of the sampling-probe tip. Perturbation of the OH concentration profile using various sampling probes indicate the importance of minimizing the length of the sampling-orifice channel to reduce composition relaxation during sampling.

  6. Characterizing Excavation Damaged Zone and Stability of Pressurized Lined Rock Caverns for Underground Compressed Air Energy Storage

    Science.gov (United States)

    Kim, Hyung-Mok; Rutqvist, Jonny; Jeong, Ju-Hwan; Choi, Byung-Hee; Ryu, Dong-Woo; Song, Won-Kyong

    2013-09-01

    In this paper, we investigate the influence of the excavation damaged zone (EDZ) on the geomechanical performance of compressed air energy storage (CAES) in lined rock caverns. We conducted a detailed characterization of the EDZ in rock caverns that have been excavated for a Korean pilot test program on CAES in (concrete) lined rock caverns at shallow depth. The EDZ was characterized by measurements of P- and S-wave velocities and permeability across the EDZ and into undisturbed host rock. Moreover, we constructed an in situ concrete lining model and conducted permeability measurements in boreholes penetrating the concrete, through the EDZ and into the undisturbed host rock. Using the site-specific conditions and the results of the EDZ characterization, we carried out a model simulation to investigate the influence of the EDZ on the CAES performance, in particular related to geomechanical responses and stability. We used a modeling approach including coupled thermodynamic multiphase flow and geomechanics, which was proven to be useful in previous generic CAES studies. Our modeling results showed that the potential for inducing tensile fractures and air leakage through the concrete lining could be substantially reduced if the EDZ around the cavern could be minimized. Moreover, the results showed that the most favorable design for reducing the potential for tensile failure in the lining would be a relatively compliant concrete lining with a tight inner seal, and a relatively stiff (uncompliant) host rock with a minimized EDZ. Because EDZ compliance depends on its compressibility (or modulus) and thickness, care should be taken during drill and blast operations to minimize the damage to the cavern walls.

  7. The glow discharge inception and post-discharge relaxation of charged and neutral active particles in synthetic air at low pressure

    Science.gov (United States)

    Jovanović, A. P.; Marković, V. Lj; Stamenković, S. N.; Stankov, M. N.

    2015-11-01

    The study of dc glow discharge inception and post-discharge relaxation of charged and neutral active particles in synthetic air at low pressure is presented. The breakdown time delay dependence as a function of relaxation time \\overline{{{t}\\text{d}}}(τ ) (the memory curve) is measured and modelled from milliseconds to the saturation region determined by the cosmic rays and natural radioactivity level. Due to fast conversion \\text{N}2++{{\\text{O}}2}\\to {{\\text{N}}2}+\\text{O}2+ , relaxation of dc discharge in synthetic air in the time interval from one to about ninety milliseconds is dominated by the diffusion decay of molecular oxygen {{O}}_2^ + ions. The change of regimes, from ambipolar to the free diffusion limit, is investigated and the variation of effective diffusion coefficients is determined. The late relaxation is explained by the kinetics of nitrogen atoms, recombining on the surfaces of gas discharge tube and stainless steel electrodes and relevant surface recombination coefficients are determined.

  8. Microwave assisted catalytic wet air oxidation of H-acid in aqueous solution under the atmospheric pressure using activated carbon as catalyst.

    Science.gov (United States)

    Zhang, Yaobin; Quan, Xie; Chen, Shuo; Zhao, Yazhi; Yang, Fenglin

    2006-09-01

    Catalytic wet air oxidation (CWAO) is a promising method for the treatment of heavily contaminated wastewater. However, its application is restricted due to severe operation conditions (high pressure and high temperature). A microwave (MW) assisted oxidation method was investigated aiming to treat heavily contaminated wastewater under milder conditions. H-acid (1-amino-8-naphthol-3, 6-disulfonic acid) was selected as target compound to evaluate the performance of this novel process. The removal of H-acid and TOC (total organic carbon) for H-acid solution of 3000 mg/L reached as high as 92.6% in 20 min and 84.2% in 60 min, respectively under optimal conditions. The existence of activated carbon and oxygen proved to be critical for effective treatment. The activated carbon acted not only as a catalyst for H-acid decomposition, but also as a special material for the absorption of MW energy. Air was supplied to the reactor as an oxygen source at constant flows. The amino group in H-acid was converted ultimately into nitrate, and sulfonic group into sulfate. This observation gave an evidence of H-acid mineralization although other organic intermediates were unable to be determined. The value of BOD(5)/COD (ratio of 5d biochemical oxygen demand to chemical oxygen demand) increased from 0.008 to 0.467 indicating a significant improvement of biodegradability for the solution, which is beneficial for the further biological treatment of the wastewater.

  9. Development of numerical model to investigate the laser driven shock waves from aluminum target into ambient air at atmospheric pressure and its comparison with experiment

    Science.gov (United States)

    Shiva, S. Sai; Leela, Ch.; Chaturvedi, S.; Sijoy, C. D.; Kiran, P. Prem

    2017-01-01

    A one-dimensional, three-temperature (electron, ion and thermal radiation) numerical model was developed to study the laser induced shock wave (LISW) propagation from aluminum target in ambient air at atmospheric pressure. The hydrodynamic equations of mass, momentum and energy are solved by using an implicit scheme in Lagrangian form. The model considers the laser absorption to take place via inverse-bremsstrahlung due to electron-ion (e-i) process. The flux limited electron thermal energy transport due e-i and e-n thermal energy relaxation equations are solved implicitly. The experimental characterization of spatio-temporal evolution of the LISW in air generated by focusing a second harmonic (532 nm, 7ns) of Nd:YAG laser on to surface of Al is performed using shadowgraphy technique with a temporal resolution of 1.5 ns. The velocity of SW observed in the experiments over 0.2 µs-8 µs time scales was compared with the numerical results to understand the SW transition from planar to spherical evolution.

  10. Application of post-discharge region of atmospheric pressure argon and air plasma jet in the contamination control of Candida albicans biofilms

    Directory of Open Access Journals (Sweden)

    Anelise Cristina Osório Cesar Doria

    Full Text Available Introduction:Candida species are responsible for about 80% of hospital fungal infections. Non-thermal plasmas operated at atmospheric pressure are increasingly used as an alternative to existing antimicrobial strategy. This work investigates the action of post-discharge region of a non-thermal atmospheric plasma jet, generated by a gliding arc reactor, on biofilms of standard strain of Candida albicans grown on polyurethane substrate. Methods Samples were divided into three groups: (i non-treated; (ii treated with argon plasma, and (iii treated with argon plus air plasma. Subsequently to plasma treatment, counting of colony-forming units (CFU/ml and cell viability tests were performed. In addition, the surface morphology of the samples was evaluated by scanning electron microscopy (SEM and optical profilometry (OP. Results Reduction in CFU/ml of 85% and 88.1% were observed in groups ii and iii, respectively. Cell viability after treatment also showed reduction of 33% in group ii and 8% in group iii, in comparison with group i (100%. The SEM images allow observation of the effect of plasma chemistry on biofilm structure, and OP images showed a reduction of its surface roughness, which suggests a possible loss of biofilm mass. Conclusion The treatment in post-discharge region and the chemistries of plasma jet tested in this work were effective in controlling Candida albicans biofilm contamination. Finally, it was evidenced that argon plus air plasma was the most efficient to reduce cell viability.

  11. Influence of viscosity on the scattering of an air pressure wave by a rigid body: a regular boundary integral formulation

    Science.gov (United States)

    Homentcovschi, Dorel

    2008-01-01

    This paper gives a regular vector boundary integral equation for solving the problem of viscous scattering of a pressure wave by a rigid body. Firstly, single-layer viscous potentials and a generalized stress tensor are introduced. Correspondingly, generalized viscous double-layer potentials are defined. By representing the scattered field as a combination of a single-layer viscous potential and a generalized viscous double-layer potential, the problem is reduced to the solution of a vectorial Fredholm integral equation of the second kind. Generally, the vector integral equation is singular. However, there is a particular stress tensor, called pseudostress, which yields a regular integral equation. In this case, the Fredholm alternative applies and permits a direct proof of the existence and uniqueness of the solution. The results presented here provide the foundation for a numerical solution procedure. PMID:19865494

  12. In-Line Ozonation for Sensitive Air-Monitoring of a Mustard-Gas Simulant by Atmospheric Pressure Chemical Ionization Mass Spectrometry

    Science.gov (United States)

    Okumura, Akihiko

    2015-09-01

    A highly sensitive method for real-time air-monitoring of mustard gas (bis(2-chloroethyl) sulfide, HD), which is a lethal blister agent, is proposed. Humidified air containing a HD simulant, 2-chloroethyl ethyl sulfide (2CEES), was mixed with ozone and then analyzed by using an atmospheric pressure chemical ionization ion trap tandem mass spectrometer. Mass-spectral ion peaks attributable to protonated molecules of intact, monooxygenated, and dioxygenated 2CEES (MH+, MOH+, and MO2H+, respectively) were observed. As ozone concentration was increased from zero to 30 ppm, the signal intensity of MH+ sharply decreased, that of MOH+ increased once and then decreased, and that of MO2H+ sharply increased until reaching a plateau. The signal intensity of MO2H+ at the plateau was 40 times higher than that of MH+ and 100 times higher than that of MOH+ in the case without in-line ozonation. Twenty-ppm ozone gas was adequate to give a linear calibration curve for 2CEES obtained by detecting the MO2H+ signal in the concentration range up to 60 μg/m3, which is high enough for hygiene management. In the low concentration range lower than 3 μg/m3, which is equal to the short-term exposure limit for HD, calibration plots unexpectedly fell off the linear calibration curve, but 0.6-μg/m3 vapor was actually detected with the signal-to-noise ratio of nine. Ozone was generated from instrumentation air by using a simple and inexpensive home-made generator. 2CEES was ozonated in 1-m extended sampling tube in only 1 s.

  13. The manifold pressure gauge in the automotive air conditioning failure diagnosis application analysis%歧管压力计在汽车空调故障诊断中的应用分析

    Institute of Scientific and Technical Information of China (English)

    王玉群; 马越群

    2011-01-01

    空调歧管压力计是对汽车空调系统整体工作性能进行分析的一种常用且有效的工具,它不仅应用于制冷剂的加注,而且也是一种故障诊断工具。文中就歧管压力计在空调系统中不同压力显示时的故障原因进行分析,为技术人员用歧管压力计对空调系统的运行状况及其故障进行诊断与排除提供相应的理论与实践借鉴,以保证或维持空调系统正常运行。%Air manifold pressure gauge is the overall performance of automotive air conditioning system for analysis of a common and effective tool,It is not only used in the filling of refrigerant,but also a troubleshooting tool.In this paper,manifold pressure gauge pressure in the air conditioning system is displayed in different analysis of the causes of failure,For the technical staff with the manifold pressure gauge on the air conditioning system operation and fault diagnosis and rule out the theory and practice to provide the corresponding reference,To ensure the normal operation or maintenance of air conditioning systems.

  14. Degradation of cationic red GTL by catalytic wet air oxidation over Mo-Zn-Al-O catalyst under room temperature and atmospheric pressure.

    Science.gov (United States)

    Xu, Yin; Li, Xiaoyi; Cheng, Xiang; Sun, Dezhi; Wang, Xueye

    2012-03-06

    To overcome the drawback of catalytic wet air oxidation (CWAO) with high temperature and high pressure, the catalytic activity of Mo-Zn-Al-O catalyst for degradation of cationic red GTL under room temperature and atmospheric pressure was investigated. Mo-Zn-Al-O catalyst was prepared by coprecipitation and impregnation. XRD, TG-DTG, and XPS were used to characterize the resulting sample. Central composition design using response surface methodology was employed to optimize correlation of factors on the decolorization of cationic red GTL. The results show that the optimal conditions of pH value, initial concentration of dye and catalyst dosage were found to be 4.0, 85 mg/L and 2.72 g/L, respectively, for maximum decolorization of 80.1% and TOC removal of 50.9%. Furthermore, the reaction on the Mo-Zn-Al-O catalyst and degradation mechanism of cationic red GTL was studied by Electron spin resonance (ESR) and GC-MS technique. The possible reaction mechanism was that the Mo-Zn-Al-O catalyst can efficiently react with adsorbed oxygen/H(2)O to produce ·OH and (1)O(2) and finally induce the degradation of cationic red GTL. GC-MS analysis of the degradation products indicates that cationic red GTL was initiated by the cleavage of -N ═ N- and the intermediates were further oxidized by ·OH or (1)O(2).

  15. Exergy analysis and performance of a counter flow Ranque-Hilsch vortex tube having various nozzle numbers at different inlet pressures of oxygen and air

    Energy Technology Data Exchange (ETDEWEB)

    Kirmaci, Volkan [Bartin University, Faculty of Engineering, Mechanical Engineering Department, 74100 Bartin (Turkey)

    2009-11-15

    An experimental investigation is made to determine the effects of the orifice nozzle number and the inlet pressure on the heating and cooling performance of the counter flow Ranque-Hilsch vortex tube when air and oxygen used as a fluid. The orifices used at these experiments are made of the polyamide plastic material. The thermal conductivity of polyamide plastic material is 0.25 W/m C. Five orifices with nozzle numbers of 2, 3, 4, 5 and 6 have been manufactured and used during the experiments. For each one of the orifices (nozzle numbers) when used with two different fluids, inlet pressures were adjusted from 150 kPa to 700 kPa with 50 kPa increments, and the exergy efficiency was determined. During the experiments, a vortex tube is used with an L/D ratio of 15, and cold mass fraction is held constant at 0.5. As a result of the experimental study, it is determined that the temperature gradient between the hot and cold fluid is decreased with increasing of the orifice nozzle number. (author)

  16. Comparative study of zeolite 5A and zeolite 13X in air separation by pressure swing adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Shokroo, Ehsan Javadi; Meymandi, Hadiseh Khalilpour; Yadollahi, Nadia [PART-SHIMI Knowledge Based Company, Shiraz (Iran, Islamic Republic of); Farsani, Danial Jafari [Bidboland Refining Co., NIGC, Bidboland (Iran, Islamic Republic of)

    2016-04-15

    The performance of zeolites 5A and 13X is numerically investigated in oxygen separation from air by a two-bed PSA system. The effect of operating variables such as adsorption step time, PH/PL ratio and cycle time was investigated on product purity and recovery. The simulation results showed that nitrogen adsorption capacity on zeolite 13X was slightly more than the one on zeolite 5A. In the completely same operating conditions, zeolite 5A had a larger mass transfer zone than zeolite 13X. Therefore, the adsorption and desorption rate of nitrogen on zeolite 5A is less than zeolite 13X. Moreover, for the equal volume of adsorbed nitrogen on both adsorbents, zeolite 5A is more capable rather than zeolite 13X to desorb much more volume of nitrogen at certain time. Furthermore, for achieving oxygen with purity of 96%, utilizing zeolite 5A is more economical than zeolite 13X, when 5.5

  17. Shortage of compressed air is expensive. Low pressure for end customers reduces efficiency and extends processing time; Druckluftmangel ist teuer. Niedriger Druck am Endverbraucher mindert die Leistung und verlaengert die Bearbeitungszeit

    Energy Technology Data Exchange (ETDEWEB)

    Stapel, A.G.

    2002-04-02

    The efficiency of compressed air tools decreases distinctly at 0,5 bar under normal pressure. Lower efficiency of a tool extends the processing time and low pressure in distribution network rises up energy cost. [German] - Schon 0,5 bar unter Nenndruck sinkt die Leistungsfaehigkeit vieler Druckluftwerkzeuge deutlich. - Die geringere Leistung eines Werkzeuges verlaengert auch die Arbeitszeit. - Zu niedriger Druck im Netz fuehrt zu deutlich hoeheren Energiekosten. (orig.)

  18. Student Award Finalist - Simulation of the reignition of atmospheric pressure air discharges behind dielectric obstacles: comparison with experiments

    Science.gov (United States)

    Pechereau, Francois; Bourdon, Anne

    2013-09-01

    In recent years, experimental studies on plasma assisted catalysis for flue gas treatment have shown a significant reduction of pollutants at a low energetic cost. Catalyst supports are either random or organized two phase media such as pellets, monoliths or porous media. Then, in plasma reactors, atmospheric pressure discharges have to interact with many obstacles and to propagate in microcavities and pores. To better understand the discharge dynamics in these complex structures, experiments have been carried out at LPGP (Orsay, France) in a point-to-plane geometry with a dielectric plane obstacle placed in the discharge path. In this work, we have carried out discharge simulations in the experimental geometry. We have compared the dynamics of the discharge ignited at the point and its impact on the dielectric surface. Then, we have compared the conditions of a discharge reignition behind the dielectric obstacle. A good qualitative agreement with experiments has been obtained but to improve the quantitative comparison, we have carried out a detailed parametric numerical study. In this work, we will focus on the influence of the level of seed charges on the discharge reignition and discuss several physical processes that could have an impact on the level of seed charges. ALVEOPLAS project (Grant No. ANR-08-BLAN-0159-01).

  19. Numerical study with experimental comparison of pressure waves in the air intake system of an internal combustion engine

    Energy Technology Data Exchange (ETDEWEB)

    Falcao, Carlos E.G.; Vielmo, Horacio A. [Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Mechanical Engineering Dept.], E-mails: vielmoh@mecanica.ufrgs.br; Hanriot, Sergio M. [Pontifical Catholic University of Minas Gerais (PUC-Minas), Belo Horizonte, MG (Brazil). Mechanical Engineering Dept.], E-mail: hanriot@pucminas.br

    2010-07-01

    The work investigates the pressure waves behavior in the intake system of an internal combustion engine. For the purpose of examining this problem, it was chosen an experimental study in order to validate the results of the present simulation. At the literature there are several experimental studies, and some numerical simulations, but the most of the numerical studies treat the problem only in one dimension in practical problems, or two dimensions in specific problems. Using a CFD code it is possible to analyze more complex systems, including tridimensional effects. The pulsating phenomenon is originated from the periodic movement of the intake valve, and produces waves that propagate within the system. The intake system studied was composed by a straight pipe connected to a 1000 cc engine with a single operating cylinder. The experiments were carried out in a flow bench. In the present work, the governing equations was discretized by Finite Volumes Method with an explicit formulation, and the time integration was made using the multi-stage Runge-Kutta time stepping scheme. The solution is independent of mesh or time step. The numerical analysis presents a good agreement with the experimental results. (author)

  20. ICU intensive care unit application effect analysis of air-cushion pressure ulcers prevention%ICU重症监护病房应用防压疮气垫的效果分析

    Institute of Scientific and Technical Information of China (English)

    赵雪梅

    2013-01-01

    目的:探讨ICU重症监护病房应用防压疮气垫的护理效果。方法:将我院重症监护室发生压疮的高危患者40例随机分为观察组和对照组各20例,观察组给予防压疮气垫护理,对照组未采用防压疮气垫防护措施,比较两组的压疮发生率。结果:对照组患者的压疮发生率显著高于观察组,两组比较,差异具有统计学意义(P<0.05)。结论:防压疮气垫能显著降低患者的压疮发生率,是ICU防治高危压疮的有效措施之一。%Objective:To discuss the ICU intensive care unit using the nursing effect of preventing pressure ulcers mattress. Methods:to the intensive care unit 40 patients with higher risk of pressure ulcers were randomly divided into observation group and control group 20 cases, observation group was given care in the air-cushion pressure ulcers, adopt protective measures preventing pressure ulcers air cushion, the control group to compare two groups the incidence of pressure ulcers. Results:the observation group is significantly higher than the control group, the incidence of pressure ulcers in patients with two groups of comparison, the difference statistically significant(P<0.05). Conclusion:for patients with pressure ulcers prevention air cushion bed can significantly reduce the incidence of pressure ulcers, ICU is one of the effective measures of prevention and treatment of pressure ulcers in high-risk patients.

  1. Attempt of lean burn of a 4 cycle gasoline engine by the aid of low pressure air assisted in-cylinder injection; Tonai kuki nenryo funsha ni yoru lean burn no kokoromi

    Energy Technology Data Exchange (ETDEWEB)

    Hatakeyama, S.; Kondo, M.; Sekiya, Y.; Murayama, T. [Hokkaido Automotive Engineering College, Hokkaido (Japan)

    1997-10-01

    Comparable performance and exhaust emission with conventional carburetor was obtained by a low Pressure air assisted in-cylinder injection system. And lean burn of idling and light load operation till A/F=70 was realized by installing a spark Plug and a reed type injection nozzle in a divided combustion chambaer of a 4 cycle gasoline engine. 2 refs., 10 figs.

  2. Numerical Simulation and Validation Test of Air Age in Pressurization Room of Space Station%空间站密封舱空气龄分布数值模拟及试验研究

    Institute of Scientific and Technical Information of China (English)

    裴一飞; 苏新明

    2012-01-01

    The theory of air age was introduced. The effect of air age in pressurization room air quality evaluation of space station was discussed. Research progress of numerical simulation and validation test of air age distribution in pressurization room of space station domestic and abroad was summarized. Suggestions were put forward for numerical simulation and validation test of air age in pressurization room of space station.%介绍了空气龄理论,阐述了空气龄在空间站密封舱内空气品质评价方面的作用,对国内外在空间站密封舱内空气龄数值模拟、空气龄分布验证试验的研究进展进行了综述,并给出了对空间站密封舱进行空气龄数值模拟及试验研究的建议.

  3. 大气压空气等离子体羽的振动温度研究%Vibrational Temperature of Plasma Plume in Atmospheric Pressure Air

    Institute of Scientific and Technical Information of China (English)

    李雪辰; 常媛媛; 贾鹏英; 赵欢欢; 鲍文婷

    2013-01-01

    A tri-electrode discharge device was designed in a dielectric barrier discharge configurations to generate a fairly large volume plasma plume in atmospheric pressure air.The discharge characteristics of the plasma plume were investigated by an optical method.The discharge emission from the plasma plume was collected by a photomultiplier tube.It was found that the number of discharge pulse per cycle of the applied voltage increased with increasing the peak value of the applied voltage.The emission spectra of the plasma plume were collected by a spectrometer.The vibrational temperature was calculated by fitting the experimental data to the theoretical one.Results showed that the vibrational temperature of the plasma plume decreases with increasing the Up.Spatially resolved measurement of the vibrational temperature was also conducted on the plasma plume with the same method.Results showed that the vibrational temperature increases firstly and then decreases with increasing distance from the nozzle.The vibrational temperature reachs its maximum when the distance is 5.4 mm from the nozzle.These experimental phenomena were analyzed qualitatively based on the discharge theory.These results have important significance for the industrial applications of the plasma plume in atmospheric pressure air.%利用三电极介质阻挡放电装置,在大气压空气中产生了较大体积的等离子体羽.采用光学方法对该等离子体羽的特性进行了研究.发现随着外加电压峰值增加,每个外加电压周期的放电脉冲个数增加.通过采集等离子体羽的发射光谱,空间分辨地研究了放电等离子体羽的振动温度.结果表明等离子体羽的振动温度随着外加电压峰值的增加而减小;随着远离喷嘴的距离的增加,等离子体振动温度先增加后减小,当距离喷嘴5.4mm时振动温度达到最高值.对上述现象进行了定性分析.研究结果对大气压空气等离子体羽在杀菌消毒等领域的应用具有重要意义.

  4. Influence of Air Pressure on Corona at the End of the Generator Stator Bar%气压对发电机定子线棒端部电晕放电特性的影响(英文)

    Institute of Scientific and Technical Information of China (English)

    WANG Youyuan; HE Yingchun; LI Yinwei; GAO Zhan

    2012-01-01

    According to the mechanism of corona discharge at the end of the generator stator bar,a model of stator bar end corona discharge is presented.In a closed corona cage at low atmospheric pressure,the corona discharge characteristics of the stator bar end model were observed using an ultraviolet imaging instrument and an oscilloscope.The influence of atmospheric pressure on the corona inception voltage and discharge intensity was analyzed.The results show that the corona inception voltage is lower under lower atmospheric pressure;the discharge intensity is stronger under lower atmospheric pressure.The particles swarm-optimized support vector machine was employed to analyze the impacts of air pressure and humidity on the corona inception voltage.Error between the calculated value of the established model and the experimental value is less than 5%.The established model can be used to calculate the corona inception voltage of the stator bar end model.

  5. Trials of the use of high pressure compressed air for coal winning in soutirage faces. Final report; Ensayo de arranque de carbon con aire comprimido de alta presion en explotaciones por sutiraje. Informe final

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-12-31

    The company Hullera Vasco Leones (HVL) is trying to improve the results of its exploitations by means of soutirage (sublevel caving), looking for maximum vertical concentration of the product. The limitation of the present systems necessitates the use of other methods of breaking the coal block. For this reason, a trial of the high pressure compressed air blasting (DACAP) technique would appear to be appropriate. This offers the outstanding advantage of increasing the height of the coal obtained by soutirage. HVL has divided the investigation into two stages. Firstly, to study the feasibility study recommended the use of the Competidora method, using the DACAP technique for the soutirage, duplicating the distance between sublevels. The foreseen improvements are a cost reduction of 17% and an output increase of almost 9%. The trial stage of this operation started in the first six months of 1992 and results were established in relation to: working variables optimization, improvements in production and productivity, a better percentage of coal recovery and cost reductions. This document summarises the work done and the results obtained from the project.

  6. The back-diffusion effect of air on the discharge characteristics of atmospheric-pressure radio-frequency glow discharges using bare metal electrodes

    Science.gov (United States)

    Sun, Wen-Ting; Liang, Tian-Ran; Wang, Hua-Bo; Li, He-Ping; Bao, Cheng-Yu

    2007-05-01

    Radio-frequency (RF), atmospheric-pressure glow discharge (APGD) plasmas using bare metal electrodes have promising prospects in the fields of plasma-aided etching, deposition, surface treatment, disinfection, sterilization, etc. In this paper, the discharge characteristics, including the breakdown voltage and the discharge voltage for sustaining a stable and uniform α mode discharge of the RF APGD plasmas are presented. The experiments are conducted by placing the home-made planar-type plasma generator in ambient and in a vacuum chamber, respectively, with helium as the primary plasma-forming gas. When the discharge processes occur in ambient, particularly for the lower plasma-working gas flow rates, the experimental measurements show that it is the back-diffusion effect of air in atmosphere, instead of the flow rate of the gas, that results in the obvious decrease in the breakdown voltage with increasing plasma-working gas flow rate. Further studies on the discharge characteristics, e.g. the luminous structures, the concentrations and distributions of chemically active species in plasmas, with different plasma-working gases or gas mixtures need to be conducted in future work.

  7. The back-diffusion effect of air on the discharge characteristics of atmospheric-pressure radio-frequency glow discharges using bare metal electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Sun Wenting; Liang Tianran; Wang Huabo; Li Heping; Bao Chengyu [Department of Engineering Physics, Tsinghua University, Beijing 100084 (China)

    2007-05-15

    Radio-frequency (RF), atmospheric-pressure glow discharge (APGD) plasmas using bare metal electrodes have promising prospects in the fields of plasma-aided etching, deposition, surface treatment, disinfection, sterilization, etc. In this paper, the discharge characteristics, including the breakdown voltage and the discharge voltage for sustaining a stable and uniform {alpha} mode discharge of the RF APGD plasmas are presented. The experiments are conducted by placing the home-made planar-type plasma generator in ambient and in a vacuum chamber, respectively, with helium as the primary plasma-forming gas. When the discharge processes occur in ambient, particularly for the lower plasma-working gas flow rates, the experimental measurements show that it is the back-diffusion effect of air in atmosphere, instead of the flow rate of the gas, that results in the obvious decrease in the breakdown voltage with increasing plasma-working gas flow rate. Further studies on the discharge characteristics, e.g. the luminous structures, the concentrations and distributions of chemically active species in plasmas, with different plasma-working gases or gas mixtures need to be conducted in future work.

  8. Nonhomogeneous surface properties of parylene-C film etched by an atmospheric pressure He/O2 micro-plasma jet in ambient air

    Science.gov (United States)

    Wang, Tao; Yang, Bin; Chen, Xiang; Wang, Xiaolin; Yang, Chunsheng; Liu, Jingquan

    2016-10-01

    Surface properties of parylene-C film etched by an atmospheric pressure He/O2 micro-plasma jet in ambient air were investigated. The morphologies and chemical compositions of the etched surface were analyzed by optical microscopy, SEM, EDS, XPS and ATR-FTIR. The microscopy and SEM images showed the etched surface was nonhomogeneous with six discernable ring patterns from the center to the outside domain, which were composed of (I) a central region; (II) an effective etching region, where almost all of the parylene-C film was removed by the plasma jet with only a little residual parylene-C being functionalized with carboxyl groups (Cdbnd O, Osbnd Cdbnd O-); (III) an inner etching boundary; (IV) a middle etching region, where the film surface was smooth and partially removed; (V) an outer etching boundary, where the surface was decorated with clusters of debris, and (VI) a pristine parylene-C film region. The analysis of the different morphologies and chemical compositions illustrated the different localized etching process in the distinct regions. Besides, the influence of O2 flow rate on the surface properties of the etched parylene-C film was also investigated. Higher volume of O2 tended to weaken the nonhomogeneous characteristics of the etched surface and improve the etched surface quality.

  9. Air atmospheric pressure plasma jet pretreatment for drop-wise loading of dexamethasone on hydroxyapatite scaffold for increase of osteoblast attachment.

    Science.gov (United States)

    Lee, Jung-Hwan; Kwon, Jae-Sung; Kim, Yong Hee; Choi, Eun Ha; Kim, Kwang-Mahn; Kim, Kyoung-Nam

    2014-10-01

    Periodontal disease affects alveolar bone resorption around the involved teeth. To gain bone height, bone graft materials have been widely used with drug carriers. Application of an atmospheric pressure plasma jet (APPJ) treatment is widely studied due to its ability to change surface characteristics without topographical change. The aim of this study is to identify whether the air APPJ (AAPPJ) treatment before drop-wise loading performance could change loaded amount of dexamethasone, and induce increase of cell attachment and proliferation. The results suggested that AAPPJ treatment decreased the contact angle down to about 13 degrees, which increased gradually but significantly lowered at least 4 days compared to no-treated group. After AAPPJ treatment, hydrocarbon was removed with change of zeta potential into positive charge. However, the AAPPJ treatment did not change the quantity or releasing profile of dexamethasone (p > 0.05). Confocal analysis combined with DNA proliferation analysis showed increase of osteoblast attachment and proliferation. Hence, AAPPJ could be a useful pretreatment method before drop-wise loading on HA scaffold with dexamethasone for increase of osteoblast attachment.

  10. Pressure Drop Measurement of Column Weight in Disc and Doughnut Pulsed Extraction Column by External Air Purge Method%外置吹气杯测量折流板脉冲萃取柱柱重压降

    Institute of Scientific and Technical Information of China (English)

    王悦云; 李少伟; 景山

    2013-01-01

    The pressure drop of column weight was measured in a disc and doughnut pulsed extraction column with the inertial diameter of 0.3 m and height of 5.6 m by in-ternal and external air purge methods ,respectively .The experimental results show that the pressure drops of column weight measured by external air purge method are in good agreement with those by internal air purge method ,therefore ,the external air purge method is recommended to measure the pressure drop of column weight in the pulsed extraction column in plutonium purification cycle .%在内径为0.3m和高度为5.6m的折流板脉冲萃取柱中,分别采用内置吹气杯和外置吹气杯对柱重压降信号进行了测量和比较。实验结果表明,两种吹气杯安装方式所测量的结果一致。因此,为了避免由于内置吹气杯所造成的钚纯化循环脉冲萃取柱异形下澄清段的设计和加工难度,推荐可使用外置吹气杯来测量该工段的脉冲萃取柱柱重压降。

  11. 42 CFR 84.163 - Man test for gases and vapors; Type C supplied-air respirators, demand and pressure-demand...

    Science.gov (United States)

    2010-10-01

    ... requirements of the part. Air flow None None The air-supply hose with air regulating valve or orifice shall...) is applied for 5 minutes between 2 planes 7.6 cm. (3 inches) wide on opposite sides of the hose...

  12. Photosynthetic traits of five neotropical rainforest tree species: interactions between light response curves and leaf-to-air vapour pressure deficit

    Directory of Open Access Journals (Sweden)

    Marcelo Schramm Mielke

    2005-09-01

    Full Text Available Measurements of leaf gas exchange at different photosynthetic photon flux density (PPFD levels were conducted in order to compare the photosynthetic traits of five neotropical rainforest tree species, with a special emphasis on empirical mathematical models to estimate the light response curve parameters incorporating the effects of leaf-to-air vapour pressure deficit (D on the saturated photosynthetic rate (Amax. All empirical mathematical models seemed to provide a good estimation of the light response parameters. Comparisons of the leaf photosynthetic traits between different species needed to select an appropriate model and indicated the microenvironmental conditions when the data were collected. When the vapour pressure deficit inside the chamber was not controlled, the incorporation of linear or exponencial functions that explained the effects of D on leaf gas exchange, was a very good method to enhance the performance of the models.Medições das trocas gasosas foliares em diferentes níveis do densidade de fluxo de fótons fotossintéticamente ativos (PPFD foram realizadas com o objetivo de comparar as características fotossintéticas de cinco espécies arbóreas de florestas úmidas neotropicais, com especial ênfase em modelos matemáticos empíricos para estimativa de parâmetros derivados das curvas de resposta à radiação luminosa e dos efeitos da diferença de pressão de vapor entre a folha e o ar (D na taxa fotossintética em saturação luminosa (Amax. Os modelos analisados proporcionaram boas estimativas para os parâmetros derivados das curvas de resposta à radiação luminosa. Comparações entre as características fotossintéticas de diferentes espécies devem sempre considerar os modelos utilizados, seguidas de indicações pormenorizadas das condições microambientais no momento em que os dados foram coletados. Quando a diferença de pressão de vapor não for controlada artificialmente durante as medições, a

  13. Direct numerical simulations of the ignition of a lean biodiesel/air mixture with temperature and composition inhomogeneities at high pressure and intermediate temperature

    KAUST Repository

    Luong, Minhbau

    2014-11-01

    The effects of the stratifications of temperature, T, and equivalence ratio, φ{symbol}, on the ignition characteristics of a lean homogeneous biodiesel/air mixture at high pressure and intermediate temperature are investigated using direct numerical simulations (DNSs). 2-D DNSs are performed at a constant volume with the variance of temperature and equivalence ratio (T′ and φ{symbol}′) together with a 2-D isotropic velocity spectrum superimposed on the initial scalar fields. In addition, three different T s(-) φ{symbol} correlations are investigated: (1) baseline cases with T′ only or φ{symbol}′ only, (2) uncorrelated T s(-) φ{symbol} distribution, and (3) negatively-correlated T s(-) φ{symbol} distribution. It is found that the overall combustion is more advanced and the mean heat release rate is more distributed over time with increasing T′ and/or φ{symbol}′ for the baseline and uncorrelated T s(-) φ{symbol} cases. However, the temporal advancement and distribution of the overall combustion caused by T′ or φ{symbol}′ only are nearly annihilated by the negatively-correlated T s(-) φ{symbol} fields. The chemical explosive mode and Damköhler number analyses verify that for the baseline and uncorrelated T s(-) φ{symbol} cases, the deflagration mode is predominant at the reaction fronts for large T′ and/or φ{symbol}′. On the contrary, the spontaneous ignition mode prevails for cases with small T′ or φ{symbol}′, especially for cases with negative T s(-) φ{symbol} correlations, and hence, simultaneous auto-ignition occurs throughout the entire domain, resulting in an excessive rate of heat release. It is also found that turbulence with large intensity, u′, and a short time scale can effectively smooth out initial thermal and compositional fluctuations such that the overall combustion is induced primarily by spontaneous ignition. Based on the present DNS results, the generalization of the effects of T′, φ{symbol}′, and u

  14. Sensitive monitoring of volatile chemical warfare agents in air by atmospheric pressure chemical ionization mass spectrometry with counter-flow introduction.

    Science.gov (United States)

    Seto, Yasuo; Kanamori-Kataoka, Mieko; Tsuge, Koichiro; Ohsawa, Isaac; Iura, Kazumitsu; Itoi, Teruo; Sekiguchi, Hiroyuki; Matsushita, Koji; Yamashiro, Shigeharu; Sano, Yasuhiro; Sekiguchi, Hiroshi; Maruko, Hisashi; Takayama, Yasuo; Sekioka, Ryoji; Okumura, Akihiko; Takada, Yasuaki; Nagano, Hisashi; Waki, Izumi; Ezawa, Naoya; Tanimoto, Hiroyuki; Honjo, Shigeru; Fukano, Masumi; Okada, Hidehiro

    2013-03-05

    A new method for sensitively and selectively detecting chemical warfare agents (CWAs) in air was developed using counter-flow introduction atmospheric pressure chemical ionization mass spectrometry (MS). Four volatile and highly toxic CWAs were examined, including the nerve gases sarin and tabun, and the blister agents mustard gas (HD) and Lewisite 1 (L1). Soft ionization was performed using corona discharge to form reactant ions, and the ions were sent in the direction opposite to the airflow by an electric field to eliminate the interfering neutral molecules such as ozone and nitrogen oxide. This resulted in efficient ionization of the target CWAs, especially in the negative ionization mode. Quadrupole MS (QMS) and ion trap tandem MS (ITMS) instruments were developed and investigated, which were movable on the building floor. For sarin, tabun, and HD, the protonated molecular ions and their fragment ions were observed in the positive ion mode. For L1, the chloride adduct ions of L1 hydrolysis products were observed in negative ion mode. The limit of detection (LOD) values in real-time or for a 1 s measurement monitoring the characteristic ions were between 1 and 8 μg/m(3) in QMS instrument. Collision-induced fragmentation patterns for the CWAs were observed in an ITMS instrument, and optimized combinations of the parent and daughter ion pairs were selected to achieve real-time detection with LOD values of around 1 μg/m(3). This is a first demonstration of sensitive and specific real-time detection of both positively and negatively ionizable CWAs by MS instruments used for field monitoring.

  15. Surface modification of biphasic calcium phosphate scaffolds by non-thermal atmospheric pressure nitrogen and air plasma treatment for improving osteoblast attachment and proliferation

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Yu-Ri [Department and Research Institute of Dental Biomaterials and Bioengineering, College of Dentistry, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-752 (Korea, Republic of); Research Center for Orofacial Hard Tissue Regeneration, College of Dentistry, Yonsei University, Seoul 120-752 (Korea, Republic of); Kwon, Jae-Sung [Research Center for Orofacial Hard Tissue Regeneration, College of Dentistry, Yonsei University, Seoul 120-752 (Korea, Republic of); Song, Doo-Hoon [Department and Research Institute of Dental Biomaterials and Bioengineering, College of Dentistry, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-752 (Korea, Republic of); Research Center for Orofacial Hard Tissue Regeneration, College of Dentistry, Yonsei University, Seoul 120-752 (Korea, Republic of); Choi, Eun Ha [Plasma Bioscience Research Center Kwangwoon University, Seoul 139-701, 447-1 Wokgye-Dong, Nowon-Gu, Seoul (Korea, Republic of); Lee, Yong-Keun [Department and Research Institute of Dental Biomaterials and Bioengineering, College of Dentistry, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-752 (Korea, Republic of); Kim, Kyoung-Nam [Department and Research Institute of Dental Biomaterials and Bioengineering, College of Dentistry, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-752 (Korea, Republic of); Research Center for Orofacial Hard Tissue Regeneration, College of Dentistry, Yonsei University, Seoul 120-752 (Korea, Republic of); Kim, Kwang-Mahn, E-mail: kmkim@yuhs.ac [Department and Research Institute of Dental Biomaterials and Bioengineering, College of Dentistry, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-752 (Korea, Republic of); Research Center for Orofacial Hard Tissue Regeneration, College of Dentistry, Yonsei University, Seoul 120-752 (Korea, Republic of)

    2013-11-29

    Surface modifications induced by non-thermal plasma have been used extensively in biomedical applications. The attachment and proliferation of osteoblast cells are important in bone tissue engineering using scaffolds. Hence the effect of non-thermal plasma on hydroxyapatite/β-tri-calcium phosphate (HA/β-TCP) scaffolds in terms of improving osteoblast attachment and proliferation was investigated. Experimental groups were treated with non-thermal plasma for 10 min and 20 min and a control group was not treated with non-thermal plasma. For surface chemistry analysis, X-ray photoelectron spectroscopy (XPS) analysis was carried out. The hydrophilicity was determined from contact angle measurement on the surface. Atomic force microscopy analysis (AFM) was used to test the change in surface roughness and cell attachment and proliferation were evaluated using MC3T3-E1 osteoblast cells. XPS spectra revealed a decreased amount of carbon on the surface of the plasma-treated sample. The contact angle was also decreased following plasma treatment, indicating improved hydrophilicity of plasma-treated surfaces compared to the untreated disc. A significant increase in MC3T3E-1 cell attachment and proliferation was noted on plasma-treated samples as compared to untreated specimens. The results suggest that non-thermal atmospheric pressure nitrogen and air plasma treatments provide beneficial surface characteristics on HA/β-TCP scaffolds. - Highlights: ► Non-thermal plasma increased OH- and decreased C on biphasic scaffold. ► Non-thermal plasma had no effect on surface roughness. ► Non-thermal plasma resulted in hydrophilic surface. ► Non-thermal plasma resulted in better cell attachment and proliferation. ► Non-thermal plasma treatment on biphasic scaffold is useful for tissue engineering.

  16. Design and experiment of balance and low-loss air allotter in air pressure maize precision planter%气压式玉米精量播种机均匀低损配气机构设计与试验

    Institute of Scientific and Technical Information of China (English)

    殷小伟; 杨丽; 张东兴; 崔涛; 韩丹丹; 张天亮; 虞异茗

    2016-01-01

    针对气压式玉米精量播种机配气系统存在各行气流分配不均、气压损失及气流速度损耗较大的问题,基于加压导管定常不可压缩湍流模型损失理论,探明了气流损失及分配不均的原因。采用等效仿真简化模型,通过 CFD (computational fluid dynamic,CFD)仿真4种不同气路结构中气压损失及气流速度损耗,分析得出最佳气流分配方式;通过正交试验,得出分配器最优结构形式;确定了配气机构连接段最优母线形状为内凹-外凸组合型曲线,连接段长度以及组合曲线内凹外凸水平长度比是2个影响配气机构性能的关键参数,连接段长度值越大,节锥角越小,且组合曲线内凹外凸水平长度比在3附近时气压损失及速度损耗最小。与常用配气机构进行对比试验,试验结果表明,常用配气机构的气压损失在30%以上,而该低损配气机构能够将气压损失减小到10%以内,气流速度损耗不显著,各行压力一致性变异系数在4%以内。%Air pressure maize precision planter is suitable for high-speed planting which needs to work under ensured and stable air pressure. However, significant problems exist in the air supply system such as high pressure loss and velocity loss, serious heating and uneven pressure and flow supply. Air supply system seriously affects the working stability of planter. Reasonable allocation of the air flow is one of the most important factors to air pressure maize precision planter. The importance of the allotter in the air supply system cannot be ignored. To solve the problems of high loss in air pressure and velocity, this paper supplies a new type of air allotter which contains one inlet, four outlets and a connection segment with gradient combined curve. According to the theory of steady incompressible flow in pressure conduits, the phenomena of high air loss and uneven flow distribution can be interpreted. The pressure

  17. 高温高压下湿空气循环中增湿塔的计算研究%Study on Calculations of Humidification Tower with Humid Air Turbine Cycle at High Temperature and Pressure

    Institute of Scientific and Technical Information of China (English)

    丁皓; 陆小华; 吉晓燕; 秦建华

    2004-01-01

    Humidification is an important step in humid air turbine system. The calculation on humidification is carried out at 423.15-573.15K, 5-15 MPa. The results suggest that to produce high-enthalpy moist air, high water temperature and large water flow are needed. The water temperature is the most sensitive parameter to the humidification tower. And it is better for the humidification tower to work at temperature higher than 523 K when the system pressure is higher than 5 MPa. The comparison between the model used in this paper and ideal model shows that the ideal model can be used in simulation to simply the calculation when the temperature is lower than473 K and pressure is lower than 5 MPa.

  18. Analysis and Experimental Study of Air-cushion Pressure Used to Cardboard Adhesive%一种用于纸板黏合的气垫压合分析及实验研究

    Institute of Scientific and Technical Information of China (English)

    高波

    2014-01-01

    Cushion has a wide range of applications in engineering. It is a new attempt to use it in the lamination process of corrugated cardboard adhesive, to get the theoretical analysis and experimental research. It is made to numerical simulation of multi-stoma pressure distribution from a single stomatal mathematical model by using ANSYS finite element software. It can be used to the experimental device that conveyor speed, air supply’s pressure and flow, and air-cushion thickness can be adjusted. Experiments show that the device can meet analysis results by a test system for relevant parameters. The result shows that the pressure of air distribution simulation is in good agreement with the measured results. The corrugated cardboard and pressing orthogonal ex-perimental results show that is the more appropriate for the pressure of air 1000Pa, air cushion thickness 2mm, pressing time 3min, air cushion pressure used in corrugated cardboard and pressing is feasible.%将气垫用于瓦楞纸板黏合的压合工艺是一种新的尝试,为了探讨气垫压力形成、压力分布及工艺效果,进行了理论分析和实验研究。利用ANSYS有限元软件,从单个气孔的压力分布数学模型出发,对多气孔的压力分布进行数值模拟,用一种供风压力、流量、气垫厚度都可调节的气垫压合实验装置,通过相关参数测试系统,验证了分析结果。结果表明:气垫压力分布模拟与实测结果吻合较好,瓦楞纸板黏合压合正交实验表明,选用气垫压力1000Pa、气垫厚度2mm、压合时间3min是比较合适的,气垫压合用于瓦楞纸黏合压合是可行的。

  19. Effects of different pressure equalization methods on PSA and VSA processes for O2 production from air%不同均压方式对PSA和VSA空分制氧过程的影响

    Institute of Scientific and Technical Information of China (English)

    杨彦钢; 丁艳宾; 马正飞; 赵春风

    2012-01-01

    对存在于变压吸附(PSA)和真空变压吸附(VSA)空分制氧过程中的均压步骤进行研究,应用ASPEN-ADSIM软件,模拟并比较4种不同均压方式(塔顶向塔顶均压(T-T),塔底向塔底均压(B-B),塔顶和塔底双向均压(TB),塔顶向塔底均压(T-B))对过程的影响,分析均压步骤的物流浓度、流量以及均压结束时床层轴向浓度分布.结果表明:采用T-B均压方式的PSA和VSA过程得到的产品O2纯度和收率最高.在均压步骤,均降床层塔顶出气有利于死空间中O2的回收,且减少床层吸附相中N2的脱附带出,从而得到较高的产品O2收率;均升床层塔底进气可使床层N2的质量摩尔浓度前沿陡峭,塔顶洁净,因此得到较高的产品O2纯度.%The pressure equalization step in O2 production from air of pressure swing adsorption(PSA) and vacuum swing adsorption( VSA) processes was studied. Influences of four different pressure equalization modes (the two beds connected by top to top (T-T) ,bottom to bottom(B-B) ,top and bottom both sides(TB) ,top to bottom (T-B)) on O2 production from air were simulated by ASPEN-ADSIM. Accordingly , the O2 concentration and flowrate of the stream in the pressure equalization step and the bed concentration profiles at the end of pressure equalization step were investigated. Results showed that PSA and VSA processes adopting, the pressure equalization mode of T-B had the highest O2 purity and O2 recovery. During pressure equalization step, opening the outlet end of bed 1 ( experiencing the step of de-pressurizing pressure equalization) to discharge gas benefit the increasing of O2 recovery of product, but opening the inlet end of bed 2 (experiencing the step of pressurizing pressure equalization) to let gas in from bed 1 had the benefit to increasing O2 purity of product.

  20. Research on Automotive Air Conditioning Refrigerant Filling Based on Manifold Pressure Gauge%基于歧管压力计的汽车空调制冷剂加注研究

    Institute of Scientific and Technical Information of China (English)

    朱亮亮; 陆健

    2016-01-01

    Automotive air conditioning refrigerant filling, is one of the key projects of automobile maintenance. Through the refrigerant properties and manifold pressure gauge principle of work introduction, refrigerant is filled in automotive air conditioning by manifold pressure gauge, and combines with the pressure detection function, refrigerant state to judge the refrigerant filling quantity; Furthermore qualitative analyzes the six kinds of common leak detection methods. In order to improve the utilization rate of automotive air conditioning, increase the comfort of occupants.%汽车空调系统制冷剂的加注,是汽车保养和维护的关键项目之一。通过制冷剂性能和歧管压力计工作原理的介绍,利用歧管压力计进行制冷剂的加注,并结合其压力检测功能、制冷剂状态等判断制冷剂加注量;并对常用的六种检漏方法进行了定性分析。以此提高汽车空调的利用率,增加驾乘人员的舒适性。

  1. 适应新版GMP对药厂风量-压力控制的探讨%Discussion on the Control of Air Volume and Pressure in Pharmaceutical Factory to Meet the New GMP

    Institute of Scientific and Technical Information of China (English)

    付永飞; 刘燕敏; 胡崔健

    2012-01-01

    In order to better meet the requirements of the new GMP for the pharmaceutical clean room construction and environmental control, a new Smart Venturi valve is used to control air volume and pressure in the pharmaceutical cleanroom. Through analyzing and comparing the air volumes and static pressure differences before and after the transformation of the system, the results show that the Smart Venturi valve can effectively ensure the requirements of air volume and pressure control in the cleanroom.%为了更好地满足我国新版GMP对药厂洁净室的建设与环境控制的要求,采用新型的智能文丘里阀来控制药厂洁净室的风量.压力参数。通过整改前后系统送风量和静压差的比较与分析,表明智能文丘里阀能行之有效地保证洁净室风量与压力的控制要求。

  2. Pressure Drop in Cyclone Separator at High Pressure

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    For the design of pressurized circulating fluidized beds, experiments were conducted in a small cyclone with 120 mm in diameter and 300 mm in height at high pressures and at atmospheric temperatures. Influence of air leakage from the stand pipe into the cyclone was specially focused. A semi-empirical model was developed for the predic tion of the pressure drop of the cyclone separator at different operate pressures with the effect of air leakage and inlet solid loading. The operate pressure, air leakage and inlet solid loading act as significant roles in cyclone pressure drop. The pressure drop increases with the increasing of pressure and decreases with the increasing of the flow rate of air leakage from the standpipe and with the increasing of the inlet solid loading.

  3. Fault Analysis and Troubleshooting Based on Automotive Air Conditioning Pressure Detection%基于压力检测的汽车空调故障分析与排除

    Institute of Scientific and Technical Information of China (English)

    朱亮亮; 丁亚东; 段少勇

    2015-01-01

    Fault analysis and troubleshooting of automotive air conditioning system, is always the emphasis and difficulty in the common fault repair of the automobile. In this paper, by means of refrigeration system and the manifold pressure gauge principle of work introduction, manifold pressure gauge was used to detect the air conditioning system pressure, according to the comparison of testing data and normal pressure range, combined with the visual look, listen, touch and other ways, analyze possible reasons causing the fault, and puts forward diagnosis method and troubleshooting measures in detail, the final fault is solved.%汽车空调系统的故障分析和故障排除,一直是汽车常见故障维修中的重点和难点。通过制冷系统工作原理和歧管压力计工作原理的介绍,利用歧管压力计对空调制冷系统压力进行检测,根据检测数据与正常压力范围的比较,结合直观的看、听、摸等方式,分析引起故障的可能原因,并提出详细的诊断方法及排除措施,最终故障得到解决。

  4. Variable Static Pressure Control Based on LabVIEW in VAV Air-Conditioning System%基于LabVIEW的变风量空调系统变静压控制

    Institute of Scientific and Technical Information of China (English)

    程贝贝; 任庆昌

    2011-01-01

    Aiming at the current situation that system airflow control mostly used fixed static pressure control method in VAV air-conditioning project, the variable static pressure control based on LabVIEW in VAV air-conditioning system is studied in Xi' an university of architecture & technology VAV laboratory. Compared with the fixed static pressure control mode, it verified that the variable static pressure control has energy-saving potential. It achieved good results based on RBF neural network auto-tuning PID control method.%针对目前变风量空调工程中系统风量多采用定静压控制的情况,结合西安建筑科技大学变风量空调实验室为研究平台。研究了基于LabVIEW的空调系统变静压控制。经验证,与定静压控制方式相比,变静压控制具有节能潜力。采用基于RBF神经网络自整定PID的控制方法,能取得良好的效果。

  5. 基于CFD的潜艇高压气吹除主压载水舱系统模拟%The simulation research of high Pressure air blowing the main ballast tank based on CFD

    Institute of Scientific and Technical Information of China (English)

    李其修; 刘辉; 吴向君

    2012-01-01

    高压气吹除主压载水舱是潜艇舱室进水情况下最有效的应急挽回手段之一.由于高压气吹除时压载水舱中剧烈的气液混合流动,导致建立的理论模型有一定局限性.本文通过CFD中两相流VOF模型对高压气吹除压载水舱的动态过程进行仿真,分析吹除过程中压载水舱中气-液混合现象、压力变化情况及压载水舱排水速率等特点,以验证高压气吹除压载水舱的理论模型.%The high pressure air blowing ballast tanks are the most effective means of emergency to restore under flooded submarine. As the process of blowing, there will bring the flow of exquisite gas-liquid mixture in the ballast compartment. This led to the theoretical models that have certain limitations. The paper simulates the dynamic process of high-pressure air blowing ballast tanks by VOF two-phase flow model to analyze gas-liquid mixture phenomena, pressure changes, the ballast tank drainage rate during the process of blowing ballast tank, which provides the basis to theoretical models for the establishment of the high pressure air blowing ballast tanks.

  6. Analysis and experimental study on formation conditions of large-scale barrier-free diffuse atmospheric pressure air plasmas in repetitive pulse mode

    Science.gov (United States)

    Li, Lee; Liu, Lun; Liu, Yun-Long; Bin, Yu; Ge, Ya-Feng; Lin, Fo-Chang

    2014-01-01

    Atmospheric air diffuse plasmas have enormous application potential in various fields of science and technology. Without dielectric barrier, generating large-scale air diffuse plasmas is always a challenging issue. This paper discusses and analyses the formation mechanism of cold homogenous plasma. It is proposed that generating stable diffuse atmospheric plasmas in open air should meet the three conditions: high transient power with low average power, excitation in low average E-field with locally high E-field region, and multiple overlapping electron avalanches. Accordingly, an experimental configuration of generating large-scale barrier-free diffuse air plasmas is designed. Based on runaway electron theory, a low duty-ratio, high voltage repetitive nanosecond pulse generator is chosen as a discharge excitation source. Using the wire-electrodes with small curvature radius, the gaps with highly non-uniform E-field are structured. Experimental results show that the volume-scaleable, barrier-free, homogeneous air non-thermal plasmas have been obtained between the gap spacing with the copper-wire electrodes. The area of air cold plasmas has been up to hundreds of square centimeters. The proposed formation conditions of large-scale barrier-free diffuse air plasmas are proved to be reasonable and feasible.

  7. Calculation of fire-fighting air pressure water tank, pressure maintenance pump and determination of vertical compartment in hydrant system%消防气压罐、稳压泵计算及消火栓系统竖向分区确定

    Institute of Scientific and Technical Information of China (English)

    马林海; 郭尚鸣

    2015-01-01

    After the implementation of GB 50974—2014 Technical Code for Fire Protection Water Supply and Hydrant Systems, air pressure tank is adopted in temporary high pressure fire protection water supply system to prevent pressure maintenance pumps from frequent starts and stops. It is different from the stabilized air pres-sure water tank set to meet the requirement that the height setting of head water tank of fire protection water sup-ply system of temporary high pressure shall conform the static pressure requirement of fire-extinguishing installa-tion at the worst place set before the implementation of GB 50974—2014 in aspects of design philosophy and us-ing function. Although both are gas pressure water tanks specialized for fire protection and both have the function of pressure maintenance, they can neither be confused with each other, nor be applied indiscriminately in design. The design philosophy and computing method of air pressure water tank as well as the confirmation of vertical compartment of hydrant systems were introduced in detail.%GB 50974—2014《消防给水及消火栓系统技术规范》实施后设置稳压泵的临时高压消防给水系统为防止稳压泵频繁启停而采用的气压水罐,与GB 50974—2014实施前临时高压消防给水系统的高位水箱设置高度不能满足最不利处水灭火设施静压要求而设置的稳压气压水罐,虽同为消防用气压水罐,同有稳压作用,但其设计理念,使用功能有很大不同,不能混为一谈,在设计上更不能套用。详细介绍了气压水罐的设计理念和计算方法,以及由此确定消火栓系统的竖向分区。

  8. A nmnerical simulation model of a pressurized smoke-removable air supply system in a subway station%正压送风防烟在地铁车站应用的模拟分析

    Institute of Scientific and Technical Information of China (English)

    梁强; 魏东

    2011-01-01

    This paper is inclined to introduce a numerical simulation model of a pressurized smoke-removable air supply system in a subway station developed by the present authors. As is known, subway stations are a place usually congested with large crowds. Any large-scale fire accidents, once taking place, would involve serious human casualties as well as material damages. For this purpose, the present paper intended to develop a LES field simulation software FDS to simulate some sorts of fire accidents in an Island-platform of double-decked subway station. In order to test the applicability of a pressurized air supply system in the subway stations, two scenes were laid out for our purpose of simulation. Based on the common smoke-removing theory, the pressurized air curtain system has been set up at the top of the stairs so as to create air curtain with an air-current flowing at a speed of 7 m/s, and another air-current flowing at an angle of 45° from top to bottom. The process of smoke movement in the station and the vector diagram of the velocity at stairs were obtained during the simulation. The results of our simulation demonstrate that the air supply amount calculated based on the accounting code would not be enough for the control of the high-temperature smoke through the stairs for 10 MW fires. In addition, the cold air strength cannot yet overwhelm the hot smoke current caused by the buoyancy, because the smoke flu velocity at the moment may reach 1.2 m/s. If creating an air curtain at the top of stairs, it would be possible to make the airflow velocity and direction adapted to the needs of the Code of the subway design. In such cases, the direction of the airflow may just be opposite to the crowd of residents around. Besides, since the downward flow speed can be greater than 1.5 m/s but on the wall of stair, the flow speed can be as high as 0.7 - 1.0 m/s, with the rest parts in the building, the speed are above 2.1 m/s. At the center of stair the flow speed is the

  9. Investigation on Propagation of Back-Pressure in Air-Breathing Pulse Detonation Engine%吸气式脉冲爆震发动机反压传播规律研究

    Institute of Scientific and Technical Information of China (English)

    彭畅新; 王治武; 郑龙席; 卢杰; 陈星谷

    2013-01-01

    With gasoline as fuel and air as oxidizer, experiments were performed to investigate the propagation of back-pressure in an air-breathing pulse detonation engine (PDE) with inner diameter 60mm, The back-pressure was measured at different operation frequencies ranging from 10 Hz to 30 Hz. The experimental results show that the back-pressure approximately increases linearly with increasing frequency. The ratio that the time of pressure fluctuation to a cycle time increases with increasing frequency. The pressure oscillation has a maximum value with operation frequency of 20Hz. The numerical model was developed and the characteristic of formation and propagation of the back-pressure was numerically investigated. The simulation results confirm that the back-pressure is induced by the retonation wave. The experimental and numerical results agree well, indicating that the method of simulation can reasonably reflect the propagation process of back-pressure.%以汽油为燃料,空气为氧化剂,在内径为60mm的吸气式脉冲爆震发动机上进行了反压传播规律实验研究.测量了10 ~30Hz频率范围内进气道内的反传压力.实验结果表明,进气道内的反压峰值随着工作频率的增加而增加,两者基本呈线性关系.随着工作频率的增加,压力波动的时间占每个工作循环时间的比例增加.压力脉动比在20Hz时达到最大.建立了数值模型,采用小能量点火及温度梯度自适应方法,计算得到了反压的形成及传播特性.计算结果印证了反压是由于回传爆震引起的.将计算结果与实验结果进行了比较,结果表明两者符合地较好.

  10. Theoretical and experimental study on pressure characteristics of air film for levitation using porous media%多孔质气悬浮气膜压力特性建模及试验研究

    Institute of Scientific and Technical Information of China (English)

    钟伟; 刘昊; 陶国良; 黎鑫; 香川利春

    2012-01-01

    为了研究多孔质气悬浮气膜压力特性以便对玻璃基板的非接触式搬运系统进行性能分析和优化设计,以具有代表性的区域单元为对象,建立包含多孔质特性和间隙流特性的气膜压力动态模型,利用有限体积法(FVM)进行求解.当多孔质表面空气薄膜受到工件的往复振动挤压时,压力响应相对间隙距离呈现明显的滞环现象,表现出弹性特性和阻尼特性.仿真和试验的结果表明,基于动态模型的计算结果与实验值吻合较好.气膜压力刚度系数随着间隙距离的减小而迅速增大,并受到供给流量与区域半径的影响.气膜压力阻尼系数受供给流量的影响甚小,受区域半径的影响显著,表明适当增加导轨宽度可以有效地加快工件自由振荡衰减速度.%A pressure dynamic model including the characteristics of porous media and gap flow was established within a representative region in order to analyze the air film pressure characteristics of pneumatic levitation using porous media, as for performance analysis and optimal design of non-contact conveying system. The model was solved by using finite volume method (FVM). Results showed that there exists an obvious pressure hysteresis versus gap thickness when a work piece was vibrated back and forth to squeeze the air film, revealing that the pressure response was identified as a representation of spring-damping characteristic. Theoretical and experimental results showed that the dynamic model based calculated results accorded well with the experimental data. Pressure stiffness coefficient of the air film increased greatly as a gap thickness decreased, and varied with the supply flow rate as well as the region radius. Pressure damping coefficient little changed with the supply flow rate, but apparently affected by the region radius, indicating that the decay of free vibration of the work piece can be accelerated by appropriately increasing the width of the conveyor.

  11. A TWO-PHASE FLOW MODEL FOR SIMULATING AIR ENTRAPMENT DURING MOLD FILLING OF HIGH PRESSURE DIE CASTING PROCESS%应用两相流模型模拟压铸充型过程的卷气现象

    Institute of Scientific and Technical Information of China (English)

    李帅君; 熊守美; Mei Li; John Allison

    2009-01-01

    通过对压铸充型过程中卷气缺陷形成机理的分析,认为型腔中空气的流动以及与金属液之间的相互作用是形成卷气现象的主要原因.为了考虑型腔中空气的流动,采用了一种不可压缩两相流数学模型来模拟压铸充型过程的卷气现象.通过计算流体力学中的两个基准算例,较为全面地验证了该模型的准确性和可靠性.在此基础上,设计了专门针对压铸充型过程的高速水模拟实验,通过对可视化实验结果与两相流模拟结果的比较,证实二者吻合较好,说明了该模型能够较好地模拟液体的充填行为和卷入其中的气泡.%The most common defect found in high pressure die casting (HPDC) process is the gas porosity which significantly affects the mechanical properties of the final components. The generation of gas porosity is known mainly due to the air entrapment in the liquid metal during the mold filling stage. Knowing the trapped-air location and amount could allow for a more accurate and objective analysis of casting quality. In the past few decades, extensive efforts have been made to develop simulation codes of casting flow. Most of these codes solve the velocity, pressure and fluid fraction only in the liquid phase with the assumption that the effect of air in the die cavity is negligible. As a matter of fact, the air in the die cavity has significant influence on the filling pattern of the molten metal and the gas porosity distribution of the die casts. Recently, following the development of computational fluid dynamics (CFD), two-phase flow models have drawn continuous attention in the numerical simulation of casting processes, but there are still few models and further studies are needed. In this study, the mechanism of the formation of air entrapment defects in the HPDC process was discussed and it turned out that the air flow in the die cavity as well as the interaction between air and liquid metal resulted in the final air

  12. 大气介质定压条件下煤的瓦斯解吸规律模拟实验研究%Simulation Experiment Study on the Gas Desorption Laws in Air Medium Pressure Conditions

    Institute of Scientific and Technical Information of China (English)

    李奇

    2015-01-01

    In this paper, by using simulation test device for air medium coal gas desorption process of different metamorphic de⁃gree of coal sample collection, under the condition of different particle size, gas pressure, simulation of coal sample in air medium coal gas desorption process, affecting air medium coal gas desorption process, the main factors are described to simulate air medium under the condition of constant pressure gas desorption process of ideal theory empirical formula. It is not only beneficial to improve the stabil⁃ity and the accuracy of coal bed gas content measurement method, but is more advantageous to improve the level of coal mine gas pre⁃vention and control technology in our country and coal resource evaluation level.%文章通过利用大气介质中煤的瓦斯解吸过程模拟试验装置采集不同变质程度煤样,在不同粒度、瓦斯压力条件下,模拟煤样在大气介质中煤的瓦斯解吸过程,找出影响大气介质中煤的瓦斯解吸过程的主控因素,得到表述模拟大气介质等压条件下瓦斯解吸过程较为理想的经验式。这不仅有利于提高煤层瓦斯含量测定方法的稳定性与准确性,更有利于提高我国煤矿瓦斯防治技术水平和煤矿资源评价水平。

  13. A change in the electro-physical properties of narrow-band CdHgTe solid solutions acted upon by a volume discharge induced by an avalanche electron beam in the air at atmospheric pressure

    Science.gov (United States)

    Voitsekhovskii, A. V.; Grigor'ev, D. V.; Korotaev, A. G.; Kokhanenko, A. P.; Tarasenko, V. F.; Shulepov, M. A.

    2012-03-01

    The effect of a nanosecond volume discharge forming in an inhomogeneous electrical field at atmospheric pressure on the CdHgTe (MCT) epitaxial films of the p-type conduction with the hole concentration 2·1016 cm3 and mobility 500 cm2·V-1·s-1 is studied. The measurement of the electrophysical parameters of the MCT specimens upon irradiation shows that a layer exhibiting the n-type conduction is formed in the near-surface region of the epitaxial films. After 600 pulses and more, the thickness and the parameters of the layer are such that the measured field dependence of the Hall coefficient corresponds to the material of the n-type conduction. Analysis of the preliminary results reveals that the foregoing nanosecond volume discharge in the air at atmospheric pressure is promising for modification of electro-physical MCT properties.

  14. Case Study regarding the test of the new screw compressor with high delivery pressure - 45 bara - on the test bench (with air

    Directory of Open Access Journals (Sweden)

    Valentin PETRESCU

    2012-12-01

    Full Text Available Screw compressors, which are part of positive displacement compressors, can find an increasing use in gas industry and beyond due to their advantages. Maximal parameters of these devices, done by Comoti under GHH-Rand license stop at a maximum flow of 3000 Nm3/hour and 26 bara discharge pressure. The needs of potential beneficiaries have imposed the necessity to design and manufacture a new family of screw compressors and oil injection able to develop a discharge pressure of 45 bara with flow rates up to 5000 Nm3/hour. This paper presents the design and experimental test phases – for the first screw compressor with discharge of pressure up to 45 bara – CU90 HP. Continue research and development have allowed to this type of screw-compressor – to find a market position, diversifying its size range in the last decade in a manner more explosive, if we refer to other types of compressors.

  15. Connectable solar air collectors

    Energy Technology Data Exchange (ETDEWEB)

    Oestergaard Jensen, S.; Bosanac, M.

    2002-02-01

    The project has proved that it is possible to manufacture solar air collector panels, which in an easy way can be connected into large collector arrays with integrated ducting without loss of efficiency. The developed connectable solar air collectors are based on the use of matrix absorbers in the form of perforated metal sheets. Three interconnected solar air collectors of the above type - each with an transparent area of approx. 3 m{sup 2} - was tested and compared with parallel tests on two single solar air collectors also with a transparent area of approx. 3 m{sup 2} One of the single solar air collectors has an identical absorber as the connectable solar air collectors while the absorber of the other single solar air collector was a fibre cloth. The efficiency of the three solar air collectors proved to be almost identical in the investigated range of mass flow rates and temperature differences. The solar air collectors further proved to be very efficient - as efficient as the second most efficient solar air collectors tested in the IEA task 19 project Solar Air Systems. Some problems remain although to be solved: the pressure drop across especially the connectable solar air collectors is too high - mainly across the inlets of the solar air collectors. It should, however, be possible to considerably reduce the pressure losses with a more aerodynamic design of the inlet and outlet of the solar air collectors; The connectable solar air collectors are easy connectable but the air tightness of the connections in the present form is not good enough. As leakage leads to lower efficiencies focus should be put on making the connections more air tight without loosing the easiness in connecting the solar air collectors. As a spin off of the project a simple and easy way to determine the efficiency of solar, air collectors for pre-heating of fresh air has been validated. The simple method of determining the efficiency has with success been compared with an advance method

  16. Flow Rate Calculation in the Auto Air Leakage Volume Test System Based on Constant Pressure Method%基于恒压法的汽车整车漏风量测试系统流量计算

    Institute of Scientific and Technical Information of China (English)

    李亚; 赵鑫; 李振亮; 许玮

    2013-01-01

    An auto air leakage volume test system based on constant pressure method was designed. Using standard orifice plate as throttle device,after testing some original data such as the differential pressure between both sides of the throttle device,temperature of the dry-bulb and the wet-bulb,and so on,the auto air leakage volume can be calculated. The formulas and methods involved were demonstrated in detail and the experiment was designed based on an analysis of the measurement theory. According to the result of the experiment,this method proved stable and reliable and can satisfy the requirement of the measurement.%  设计了基于恒压法的汽车整车漏风量测试系统。采用标准孔板作为节流件,通过测量节流件上下游的压力差、干球温度和湿球温度等基础数据,经过计算可得到整车漏风量。在分析测量原理的基础上,详细给出了计算漏风量的公式和方法,并进行了实验。实验结果表明,该计算方法稳定可靠,可满足测量要求。

  17. Application of Pressure Relief Tee Joint in Air Duct in Mengjin Coal Mine%风筒卸压三通在孟津煤矿局部通风中的应用

    Institute of Scientific and Technical Information of China (English)

    马凯

    2015-01-01

    The equipment of pressure relief tee joint was made to solve a series of problems about air duct management and gas prevention caused by high power local ventilation fan and large diameter flowing tube in Mengjin coal mine. The application of pressure relief tee joint solved the problems well, provided convenient air duct management, improved the work environment of working spot and assure the safety production.%为解决孟津煤矿井下局部通风中由大功率局部通风机和大直径风筒引起的风筒管理和通风瓦斯防治方面的一系列难题,加工制作了风筒卸压三通装置。卸压三通的使用能很好解决这些难题,方便了风筒管理,改善了作业现场的工作环境,保证了安全生产。

  18. Study of far-field pressure wavelet of air-gun bubble based on p otential flow theory%基于势流理论的气枪气泡远场压力子波特性研究

    Institute of Scientific and Technical Information of China (English)

    叶亚龙; 李艳青; 张阿漫

    2014-01-01

    The study of far-field pressure wavelet of air-gun bubble is the basic research of air-gun sources. In this paper, a boundary element bubble model is established to simulate the dynamics of bubble, and an energy equivalent method is put forward to solve the bottleneck of bubble jet. In our simplified model, the bubble model takes into consideration the thermodynamic factors such as heat transfer and gas release, and the numerical results agree with the data of Nucleus software well. Based on the established model, the influence of heat transfer coefficient, air-gun firing time, and specific heat at constant volume on the pressure wavelet are studied. Finally, the three-dimensional bubble merging numerical method is put forward, which is an expansion of the axisymmetric model. Thus, the preliminary study of coherent air-gun is conducted, especially the influence of the space between two bubbles on the wavelet. This paper provides a reference for the research of air-gun.%气枪气泡的远场压力子波特性研究是研究气枪震源的基础,本文在前人研究基础上建立了三维边界元气泡动力学模型,并针对气泡射流这一技术瓶颈提出了能量等效算法。再在上述模型中加入了简化的热力学模型,考虑了气枪释放气体以及气泡传热等热力学因素,将上面模型计算结果和Nucleus软件模拟结果对比,两者符合良好,并以此为基础探讨了传热系数、气枪发射时间、气体等体比热容对气枪主要参数的影响规律。最后将轴对称气泡融合技术拓展到三维边界元模型,对相干枪进行初步研究,探讨了气枪间距对压力子波的影响规律,旨在为气枪的研究提供参考。

  19. Air Blast Calculations

    Science.gov (United States)

    2013-07-01

    gauges at this point are still inside the explosive fireball (where the pressure time histories are dramatically influenced by the propagating...outside of the explosive fireball (since no evidence of an air-product interface is detected in any of the pressure time histories at this point

  20. Determinação de volumes e pressões de balonetes de tubos traqueais insuflados com ar ambiente ou óxido nitroso Determinación de volúmenes y presiones de balones de tubos traqueales insuflados con aire ambiente u óxido nitroso Volume and pressure of tracheal tube cuffs filled with air or nitrous oxide

    Directory of Open Access Journals (Sweden)

    Ernesto Leonardo Cárpio Peña

    2004-06-01

    balanceada con entubación orotraqueal. El balón fue insuflado conforme criterios clínicos. Las medidas de base fueron realizadas después de 15 minutos del inicio de la anestesia con un manómetro aneróide calibrado en cm de H2O y dieron los valores iniciales de presión y volumen. Los pacientes fueron divididos en dos grupos: balón reinsuflado con aire ambiente, grupo A, o con óxido nitroso, grupo B. Las medidas de presión fueron obtenidas en intervalos hasta la primera hora y los resultados comparados. RESULTADOS: Los grupos se mostraron comparables para edad y sexo. En ambos grupos los valores basales medios para presión fueron próximos de 40 cmH2O con 8 ml de volumen. En el grupo con aire ambiente, las presiones aumentaron hasta 36 cmH2O en una hora. En el grupo de balón insuflado con N2O, las presiones cayeron abajo de 20 cmH2O entre 20 y 30 minutos de anestesia. CONCLUSIONES: El uso de N2O a 100% para insuflación del balón de sonda traqueal no constituye método seguro, acarreando progresiva pérdida de la capacidad de vedación. El uso de aire ambiente promueve aumento de volumen y de presión en el balón, aumentando la posibilidad de lesión de la mucosa traqueal.BACKGROUND AND OBJECTIVES: Tracheal tube cuff pressure against tracheal wall should to prevent air leaked or pulmonary aspiration, allowing adequate capillary blood flow. This study aimed at determining pressure variations of tracheal tube cuffs filled with air or 100% nitrous oxide. METHODS: Participated in this study 30 patients submitted to balanced general anesthesia with tracheal intubation. Cuff was inflated according to clinical criteria. The intracuff pressure measurements were undertaken after 15 minutes of anesthesia by means of an aneroid manometer gaged in cm of H2O and have provided initial pressure and volume values. The patients was allocated in two groups: cuff inflated with air, group A, and with nitrous oxide, group B. Measurements were recorded during one hour and results were

  1. Slug flow transitions in horizontal gas/liquid two-phase flows. Dependence on channel height and system pressure for air/water and steam/water two-phase flows

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Hideo [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1996-05-01

    The slug flow transitions and related phenomena for horizontal two-phase flows were studied for a better prediction of two-phase flows that typically appear during the reactor loss-of-coolant accidents (LOCAs). For better representation of the flow conditions experimentally, two large-scaled facility: TPTF for high-pressure steam/water two-phase flows and large duct test facility for air/water two-phase flows, were used. The visual observation of the flow using a video-probe was performed in the TPTF experiments for good understanding of the phenomena. The currently-used models and correlations based mostly on the small-scale low-pressure experiments were reviewed and improved based on these experimental results. The modified Taitel-Dukler model for prediction of transition into slug flow from wavy flow and the modified Steen-Wallis correlation for prediction of onset of liquid entrainment from the interfacial waves were obtained. An empirical correlation for the gas-liquid interfacial friction factor was obtained further for prediction of liquid levels at wavy flow. The region of slug flow regime that is generally under influences of the channel height and system pressure was predicted well when these models and correlations were applied together. (author). 90 refs.

  2. 均压工作面造成总回压能升高后通风系统稳定性安全措施%Study on the stability of ventilation system after rising total return air pressure energy caused by pressure working face

    Institute of Scientific and Technical Information of China (English)

    夏春光

    2015-01-01

    For the safety recovery of coal pillar, preventing hazard gas from gob to leak, in the fully mechanized face pressure ventilation process, increasing the total return air pressure energy resulted in other using wind place wind direction changes, so that the ventilation system has great potential safety hazard. in view of this phenomenon, on the pressure energy of the affected region was measured by using JFY-2 type of mine ventilation parameters instrument, taking reasonable use of the method of increasing resistance to change the use wind point pressure energy, so that the ventilation system restore stability, and ensure the safety production of mine.%为安全回收煤柱,防止小窑采空区有害气体泄出,在对综采工作面采用均压通风过程中,造成总回压能升高,其他用风地点风流方向发生变化,使通风系统存在安全隐患。针对此种现象,通过利用JFY-2型矿井通风参数仪对受影响区域内各点压能进行测定,利用增阻法改变各用风点处压能,使通风系统恢复稳定,确保矿井安全生产。

  3. Practice of pressure adjusting technology by air chamber piping system for controlling gas in goaf%气室连通管调压技术调控矿井采空区瓦斯涌出实践

    Institute of Scientific and Technical Information of China (English)

    华德宏

    2011-01-01

    在煤矿无煤柱开采过程中,采煤工作面及其作业空间往往因处于空气压能相对低位,受到邻近采空区内瓦斯等有害气体侵入的威胁.通过研究和实施气室连通管调压技术,合理改变采煤工作面邻近老空区外围的压能关系,调控老空区瓦斯涌出方向和涌出量,有效阻止老空区高浓度瓦斯侵入回采工作面作业空间.%With respect to the pillarless mining operations, the mining district and its working faces were very much prone to the exposure of harmful gases originated from the adjoining goaf as the pressure energy at the mining district was relatively lower. Given this a gas chamber piping system was proposed where the ventilation system was not allowed to be adjusted or such regulations were not favorable. To be specific, auxiliary retaining walls were to be constructed to form a gas chamber along with the original goaf retaining wall located in the air intake roadway. A piping system then could be used to release harmful gases through the auxiliary retaining wall to the main air return roadway. The pressure energy distribution around the goaf would be properly regulated to increase the pressure energy of working area nearby the goaf,at the same time, the gas density of the main air return was lower than the limit and not causing coal spontaneous combustion. In this way harmful gases trapped in the gas chamber could be released through the underground ventilation system. This method was successfully implemented at Kongzhuang Coal Mine and the results proved to be satisfactory. The goaf gas risks were dramatically reduced and mining safety was ensured to the maximum extent.

  4. Ion mobility spectrometry-mass spectrometry studies of ion processes in air at atmospheric pressure and their application to thermal desorption of 2,4,6-trinitrotoluene

    Science.gov (United States)

    Sabo, Martin; Malásková, Michaela; Matejčík, Štefan

    2014-02-01

    In this study we have investigated the negative reactant ion formation in a negative corona discharge (CD) using the corona discharge ion mobility spectrometry orthogonal acceleration time-of-flight (CD-IMS-oaTOF) technique. The reactant ions were formed in the CD operating in the reverse gas flow mode at an elevated temperature of 363.5 K in synthetic and ambient air. Under these conditions mainly O_{2}^{-} and their clusters were formed. We have also studied the influence of CCl4 admixture to air (dopant gas) on the composition of the reactant ions, which resulted in the formation of Cl- and its clusters with a reduced ion mobility of 3.05 cm2 V-1 s-1 as a major reactant ion peak. Additional IMS peaks with reduced ion mobilities of 2.49, 2.25 and 2.03 cm2 V-1 s-1 were detected, and Cl- · (NO2) and Cl- · (NO)n(n = 2, 3) anions were identified. The negative reactant ions were used to detect 2,4,6 trinitrotoluene (TNT) using the thermal desorption (TD) technique using a CD-IMS instrument. Using TD sampling and a negative CD ion source doped by CCl4 we have achieved a limit of detection of 350 pg for direct surface analysis of TNT.

  5. Suprathermal electron energy spectrum and nonlocally affected plasma-wall interaction in helium/air micro-plasma at atmospheric pressure

    Science.gov (United States)

    Demidov, V. I.; Adams, S. F.; Miles, J. A.; Koepke, M. E.; Kurlyandskaya, I. P.

    2016-10-01

    Details of ground-state and excited-state neutral atoms and molecules in an atmospheric-pressure micro-discharge plasma may be obtained by plasma electron spectroscopy (PLES), based on a wall probe. The presence and transport of energetic (suprathermal) electrons, having a nonlocal origin, are responsible for electrostatic charging of the plasma boundary surfaces to potentials many times that associated with the ambient electron kinetic energy. The energy-flux distribution function is shown to be controllable for applications involving analysis of composition and processes taking place in a multiphase (plasma-gas-solid), chemically reactive, interaction region.

  6. Effect of Pulse Nanosecond Volume Discharge in Air at Atmospheric Pressure on Electrical Properties of Mis Structures Based on p-HgCdTe Grown by Molecular Beam Epitaxy

    Science.gov (United States)

    Voitsekhovskii, A. V.; Nesmelov, S. N.; Dzyadukh, S. M.; Grigor'ev, D. V.; Tarasenko, V. F.; Shulepov, M. A.

    2015-11-01

    The effect of the pulse nanosecond volume discharge in air at atmospheric pressure on the admittance of MIS structures based on MBE graded-gap p-Hg0.78Cd0.22Te is studied in a wide range of frequencies and temperatures. It is shown that the impact of the discharge leads to significant changes in electrical characteristics of MIS structures (the density of positive fixed charge increases), to the changes in the nature of the hysteresis of capacitance-voltage characteristics, and to an increase in the density of surface states. A possible reason for the changes in the characteristics of MIS structures after exposure to the discharge is substantial restructuring of the defect-impurity system of the semiconductor near the interface.

  7. 浅述气压盘式制动器在城市客车上应用的可能性与可行性%Possibility and feasibility of air pressure disc brake applicated in city bus

    Institute of Scientific and Technical Information of China (English)

    孙吉宝; 温述波

    2012-01-01

    Analyse the possiblity and feasibility of air pressure disc brake applicated in city bus,focus on discussing the development of 5.5t disc brake front axle,and calculate the brake moment of disc brake front axle and drum brake front axle.%分析了气压盘式制动器在城市客车上应用的可能性与可行性,重点论述了5.5T盘式制动器前桥的开发,并对盘式制动器前桥与鼓式制动器前桥的制动力矩进行对比计算。

  8. Optical and electrical characteristics of a single surface DBD micro-discharge produced in atmospheric-pressure nitrogen and synthetic air

    Science.gov (United States)

    Šimek, M.; Prukner, V.; Schmidt, J.

    2011-05-01

    Basic opto-electrical characteristics of a single micro-discharge generated in a surface DBD reactor with a coplanar electrode arrangement were studied with nanosecond time resolution. The discharge electrode geometry based on machinable glass-ceramic was optimized in order to get a system free of the circulating dielectric liquids that are frequently used to insulate and cool metallic electrodes. The build-up and decay of UV-vis-NIR emission by a single micro-discharge unaffected by concurrent or preceding discharge events was inspected during the first 10 µs of the micro-discharge evolution in nitrogen and in synthetic air. Obtained emission waveforms show a great similarity between the surface and volume streamers. The streamer volume-averaged N2(A) concentrations of ~8 × 1014 cm-3 were estimated at t = 1 µs decay time and concentrations of ~(2-4) × 1015 cm-3 were estimated during the streamer propagation phase in nitrogen.

  9. Polymer-gas reactions (air pollutants: NO2 and SO2) as function of pressure, UV light, temperature, and morphology: A survey

    Science.gov (United States)

    Jellinek, H. H. G.

    1972-01-01

    Reactions of various polymers, such as polystyrene and its stereo-specific isomers, butylrubber, nylon, etc., with nitrogen dioxide and sulfur-dioxide were studied over the past few years. More recently, work has been initiated on the influence of polymer morphology on degradation of polymers in presence of these gases, near UV radiation and oxygen. Unexpected effects have been observed during chain scission near room temperature. Thus, for instance, isotactic polystyrene of various crystallinities, as far as extent and type are concerned, show marked differences in their degradation characteristics. Thus, for instance, crystalline polymers show faster degradation than amorphous ones, which seems to be contrary to expectations. However, this phenomenon can be explained in quite a consistent manner. The importance of all these reactions in connection with air pollution is briefly discussed.

  10. Friction and wear of sintered Alpha SiC sliding against IN-718 alloy at 25 to 800 C in atmospheric air at ambient pressure

    Science.gov (United States)

    Deadmore, Daniel L.; Sliney, Harold E.

    1986-01-01

    The sliding friction and wear of the SiC-nickel based alloy IN-718 couple under line contact test conditions in atmospheric air at a linear velocity of 0.18 m/sec and a load of 6.8 kg (67N) was investigated at temperatures of 25 to 800 C. It was found that the coefficient of friction was 0.6 up to 350 C then decreased to 0.3 at 500 and 800 C. It is suggested that the sharp decrease in the friction in the range of 350 to 550 C is due to the lubrication value of oxidation products. The wear rate reaches a minimum of 1 x 10 to the -10 to 2 x 10 to the -10 cu cm/cm/kg at 400 to 600 C.

  11. The effects of channel diameter on flow pattern, void fraction and pressure drop of two-phase air-water flow in circular micro-channels

    Energy Technology Data Exchange (ETDEWEB)

    Saisorn, Sira [Energy Division, The Joint Graduate School of Energy and Environment (JGSEE), King Mongkut' s University of Technology Thonburi, Bangmod, Bangkok 10140 (Thailand); Wongwises, Somchai [Fluid Mechanics, Thermal Engineering and Multiphase Flow Research Lab. (FUTURE), Department of Mechanical Engineering, King Mongkut' s University of Technology Thonburi, Bangmod, Bangkok 10140 (Thailand)

    2010-05-15

    Two-phase air-water flow characteristics are experimentally investigated in horizontal circular micro-channels. Test sections are made of fused silica. The experiments are conducted based on three different inner diameters of 0.53, 0.22 and 0.15 mm with the corresponding lengths of 320, 120 and 104 mm, respectively. The test runs are done at superficial velocities of gas and liquid ranging between 0.37-42.36 and 0.005-3.04 m/s, respectively. The flow visualisation is facilitated by systems mainly including stereozoom microscope and high-speed camera. The flow regime maps developed from the observed flow patterns are presented. The void fractions are determined based on image analysis. New correlation for two-phase frictional multiplier is also proposed for practical applications. (author)

  12. 基于IMFAC的空压机出口压力控制%Air Compressor Outlet Pressure Control Based on IMFAC

    Institute of Scientific and Technical Information of China (English)

    屠袁飞; 高翀

    2015-01-01

    以南京某石化企业的空分设备为背景,根据空压机非线性、时变、大时滞等特点,使用了一种改进的无模型自适应控制( IMFAC),设计IMFAC-PID串级控制方案,并利用MATLAB/Simulink进行仿真。仿真结果证明,IMFAC具有调节时间短、超调量小、响应速度快等特点。与基本无模型自适应控制和PID控制相比,使用IMFAC-PID的系统具有更好的鲁棒性、更快的响应速度和更高的稳态精度。%In the context of air separation plant of a petrochemical enterprise in Nanjing,based on the air compressor has the characteristics of nonlinear,time-varying and large time delay,an improved model-free adaptive control ( IMFAC) was used,the IMFAC-PID cascade control scheme was designed and a simulation was carried out by adopting Matlab simulation software. The simulation result shows that improved model-free adaptive control has shorter setting time, less overshoot and higher response speed.Compared with the basic model-free adaptive control and PID control,the system has better robustness,higher response speed and steady-state accuracy using IMFAC-PID.

  13. In-air and pressurized water reactor environment fatigue experiments of 316 stainless steel to study the effect of environment on cyclic hardening

    Science.gov (United States)

    Mohanty, Subhasish; Soppet, William K.; Majumdar, Saurindranath; Natesan, Krishnamurti

    2016-05-01

    Argonne National Laboratory (ANL), under the sponsorship of Department of Energy's Light Water Reactor Sustainability (LWRS) program, is trying to develop a mechanistic approach for more accurate life estimation of LWR components. In this context, ANL has conducted many fatigue experiments under different test and environment conditions on type 316 stainless steel (316 SS) material which is widely used in the US reactors. Contrary to the conventional S ∼ N curve based empirical fatigue life estimation approach, the aim of the present DOE sponsored work is to develop an understanding of the material ageing issues more mechanistically (e.g. time dependent hardening and softening) under different test and environmental conditions. Better mechanistic understanding will help develop computer-based advanced modeling tools to better extrapolate stress-strain evolution of reactor components under multi-axial stress states and hence help predict their fatigue life more accurately. Mechanics-based modeling of fatigue such as by using finite element (FE) tools requires the time/cycle dependent material hardening properties. Presently such time-dependent material hardening properties are hardly available in fatigue modeling literature even under in-air conditions. Getting those material properties under PWR environment, are even harder. Through this work we made preliminary attempt to generate time/cycle dependent stress-strain data both under in-air and PWR water conditions for further study such as for possible development of material models and constitutive relations for FE model implementation. Although, there are open-ended possibility to further improve the discussed test methods and related material estimation techniques we anticipate that the data presented in this paper will help the metal fatigue research community particularly, the researchers who are dealing with mechanistic modeling of metal fatigue such as using FE tools. In this paper the fatigue experiments

  14. Diseño en cosmosfloworks del conducto experimental para la medición de la caída de presión del aire al paso de bandejas metálicas Cosmosfloworks design of an experimental duct for measurement of the drop in air pressure after its passage through metal trays

    Directory of Open Access Journals (Sweden)

    Alejandro Escalante

    2009-07-01

    Full Text Available En el siguiente artículo se presenta el proceso de desarrollo de diseño del conducto experimental que facilita la medición de la caída de presión del aire tras su paso por bandejas metálicas. El diseño se fundamenta en los resultados arrojados por las simulaciones realizadas a diferentes disposiciones en la etapa inicial del conducto, y la validación de los datos de la simulación más representativa con un prototipo del conducto real con esta misma distribución. Para este estudio se usó software Cosmosfloworks [1], con el cual se analizaron las líneas de corriente y la caída de presión del fluido en el conducto.The following article presents the development’s process of designing an experimental duct which facilitates the measurement of the drop in air pressure after its going through metal trays. The design is based on the results of simulations conducted at various provisions of the duct, and validation of data from the most representative simulation through actual prototype with the same distribution. For this study, we used [1], with which curves of fluid and pressure drop of the fluid were analyzed.

  15. Fiber Optic Pressure Sensor Array Project

    Data.gov (United States)

    National Aeronautics and Space Administration — VIP Sensors proposes to develop a Fiber Optic Pressure Sensor Array System for measuring air flow pressure at multiple points on the skin of aircrafts for Flight...

  16. Fiber Optic Pressure Sensor Array Project

    Data.gov (United States)

    National Aeronautics and Space Administration — VIP Sensors proposes to develop a Fiber Optic Pressure Sensor Array for measuring air flow pressure at multiple points on the skin of aircrafts for Flight Load Test...

  17. Collision-Induced Dissociation Study of the Adduct Ions Produced in NO3 (-)-Free Area of Atmospheric Pressure Negative Corona Discharges under Ambient Air Conditions.

    Science.gov (United States)

    Sekimoto, Kanako; Matsuda, Natsuki; Takayama, Mitsuo

    2013-01-01

    Collision-induced dissociation (CID) experiments of adducts [M+R](-) with negative atmospheric ions R(-) (O2 (-), HCO3 (-) and COO(-)(COOH)) produced in NO3 (-)-free discharge area in atmospheric pressure corona discharge ionization (APCDI) method were performed using aliphatic and aromatic compounds M. The [M+R](-) adducts for individual R(-) fragmented to form deprotonated analytes [M-H](-) as well as the specific product ions which also occurred in the CID of [M-H](-), independent of analytes with several different functional groups. The results obtained suggested that the specific product ions formed in the CID of [M+R](-), as well as CID of [M-H](-), are generated due to further fragmentation of the product ions [M-H](-). It was concluded, therefore, that CID of [M+R](-) formed in NO3 (-)-free discharge area can indirectly lead to the formation of the product ions originating from [M-H](-).

  18. An improved high performance liquid chromatography-photodiode array detection-atmospheric pressure chemical ionization-mass spectrometry method for determination of chlorophylls and their derivatives in freeze-dried and hot-air-dried Rhinacanthus nasutus (L.) Kurz.

    Science.gov (United States)

    Kao, Tsai Hua; Chen, Chia Ju; Chen, Bing Huei

    2011-10-30

    Rhinacanthus nasutus (L.) Kurz, a traditional Chinese herb possessing antioxidant and anti-cancer activities, has been reported to contain functional components like carotenoids and chlorophylls. However, the variety and amount of chlorophylls remain uncertain. The objectives of this study were to develop a high performance liquid chromatography-photodiode array detection-atmospheric pressure chemical ionization-mass spectrometry (HPLC-DAD-APCI-MS) method for determination of chlorophylls and their derivatives in hot-air-dried and freeze-dried R. nasutus. An Agilent Eclipse XDB-C18 column and a gradient mobile phase composed of methanol/N,N-dimethylformamide (97:3, v/v), acetonitrile and acetone were employed to separate internal standard zinc-phthalocyanine plus 12 cholorophylls and their derivatives within 21 min, including chlorophyll a, chlorophyll a', hydroxychlorophyll a, 15-OH-lactone chlorophyll a, chlorophyll b, chlorophyll b', hydroxychlorophyll b, pheophytin a, pheophytin a', hydroxypheophytin a, hydroxypheophytin a' and pheophytin b in hot-air-dried R. nasutus with flow rate at 1 mL/min and detection at 660 nm. But, in freeze-dried R. nasutus, only 4 chlorophylls and their derivatives, including chlorophyll a, chlorophyll a', chlorophyll b and pheophytin a were detected. Zinc-phthalocyanine was found to be an appropriate internal standard to quantify all the chlorophyll compounds. After quantification by HPLC-DAD, both chlorophyll a and pheophytin a were the most abundant in hot-air-dried R. nasutus, while in freeze-dried R. nasutus, chlorophyll a and chlorophyll b dominated.

  19. Real-time air monitoring of mustard gas and Lewisite 1 by detecting their in-line reaction products by atmospheric pressure chemical ionization ion trap tandem mass spectrometry with counterflow ion introduction.

    Science.gov (United States)

    Okumura, Akihiko; Takada, Yasuaki; Watanabe, Susumu; Hashimoto, Hiroaki; Ezawa, Naoya; Seto, Yasuo; Sekiguchi, Hiroshi; Maruko, Hisashi; Takayama, Yasuo; Sekioka, Ryoji; Yamaguchi, Shintaro; Kishi, Shintaro; Satoh, Takafumi; Kondo, Tomohide; Nagashima, Hisayuki; Nagoya, Tomoki

    2015-01-20

    A new method enabling sensitive real-time air monitoring of highly reactive chemical warfare agents, namely, mustard gas (HD) and Lewisite 1 (L1), by detecting ions of their in-line reaction products instead of intact agents, is proposed. The method is based on corona discharge-initiated atmospheric pressure chemical ionization coupled with ion trap tandem mass spectrometry (MS(n)) via counterflow ion introduction. Therefore, it allows for highly sensitive and specific real-time detection of a broad range of airborne compounds. In-line chemical reactions, ionization reactions, and ion fragmentations of these agents were investigated. Mustard gas is oxygenated in small quantity by reactive oxygen species generated in the corona discharge. With increasing air humidity, the MS(2) signal intensity of protonated molecules of mono-oxygenated HD decreases but exceeds that of dominantly existing intact HD. This result can be explained in view of proton affinity. Lewisite 1 is hydrolyzed and oxidized. As the humidity increases from zero, the signal of the final product, namely, didechlorinated, dihydroxylated, and mono-oxygenated L1, quickly increases and reaches a plateau, giving the highest MS(2) and MS(3) signals among those of L1 and its reaction products. The addition of minimal moisture gives the highest signal intensity, even under low humidity. The method was demonstrated to provide sufficient analytical performance to meet the requirements concerning hygienic management and counter-terrorism. It will be the first practical method, in view of sensitivity and specificity, for real-time air monitoring of HD and L1 without sample pretreatment.

  20. Air Pollution

    Science.gov (United States)

    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 ...

  1. 热一次风加热器与低压省煤器的联合应用%Combined application of hot primary air heater and low pressure economizer

    Institute of Scientific and Technical Information of China (English)

    薛宁; 印旭洋; 王春昌

    2015-01-01

    A hot primary air heater (HPAH)technology was introduced,which uses the heater installed on the hot primary air duct to heat condensation water,so the steam extraction amount can be reduced to in﹣crease the turbine's work ability,thus to save the energy.Moreover,the combined application of the HPAH and low pressure economizer (LPE)was studied,and the its application in a 600MW unit was designed and calculated.The results show that,the HPAH is suitable for units with large quantity of cool air,high ex﹣haust temperature and surplus pressure margin of primary draft fan.The energy conservation potential of the LPE is lower at low load,but the HPAH is on the contrary.The combined application of them can save net coal consumption rate by more than 3 g/(kW•h)at both low and high load.%介绍了一种热一次风加热器技术,该技术通过在热一次风道上增加换热设备,加热凝结水,利用凝结水回收热量,减少汽轮机抽汽量,增加汽轮机做功能力,实现节能。同时,对热一次风加热器与低压省煤器联合应用技术进行了研究,并对某600 MW 机组的联合应用方案进行了设计与计算。结果表明:热一次风加热器技术适用于制粉系统冷风量较大、排烟温度高且一次风机压力具有一定裕量的机组;低压省煤器技术在低负荷时节能潜力降低,而热风加热器技术随负荷降低,节能能力增强,两者联合应用方案在机组高、低负荷段均可节省供电煤耗3 g/(kW•h)以上,节能效果明显。

  2. Generation of large-scale, barrier-free diffuse plasmas in air at atmospheric pressure using array wire electrodes and nanosecond high-voltage pulses

    Science.gov (United States)

    Teng, Yun; Li, Lee; Liu, Yun-Long; Liu, Lun; Liu, Minghai

    2014-10-01

    This paper introduces a method to generate large-scale diffuse plasmas by using a repetition nanosecond pulse generator and a parallel array wire-electrode configuration. We investigated barrier-free diffuse plasmas produced in the open air in parallel and cross-parallel array line-line electrode configurations. We found that, when the distance between the wire-electrode pair is small, the discharges were almost extinguished. Also, glow-like diffuse plasmas with little discharge weakening were obtained in an appropriate range of line-line distances and with a cathode-grounding cross-electrode configuration. As an example, we produced a large-scale, stable diffuse plasma with volumes as large as 18 × 15 × 15 cm3, and this discharge region can be further expanded. Additionally, using optical and electrical measurements, we showed that the electron temperature was higher than the gas temperature, which was almost the same as room temperature. Also, an array of electrode configuration with more wire electrodes had helped to prevent the transition from diffuse discharge to arc discharge. Comparing the current waveforms of configurations with 1 cell and 9 cells, we found that adding cells significantly increased the conduction current and the electrical energy delivered in the electrode gaps.

  3. Pressurized Vessel Slurry Pumping

    Energy Technology Data Exchange (ETDEWEB)

    Pound, C.R.

    2001-09-17

    This report summarizes testing of an alternate ''pressurized vessel slurry pumping'' apparatus. The principle is similar to rural domestic water systems and ''acid eggs'' used in chemical laboratories in that material is extruded by displacement with compressed air.

  4. Deterioration to extinction of wastewater bacteria by non-thermal atmospheric pressure air plasma as assessed by 16S rDNA-DGGE fingerprinting

    Directory of Open Access Journals (Sweden)

    Wael Samir El-Sayed

    2015-10-01

    Full Text Available The impact of cold atmospheric plasma on the bacterial community structure of wastewater from two different industries was investigated by metagenomic-based PCR-DGGE utilizing 16S rRNA genes. Three doses of atmospheric pressure dielectric barrier discharge plasma were applied to wastewater samples on different time scales. DGGE revealed that the bacterial community gradually changed and overall abundance decreased to extinction upon plasma treatment. The bacterial community in food processing wastewater contained 11 key operational taxonomic units that remained almost completely unchanged when exposed to plasma irradiation at 75.5 mA for 30 or 60s. However, when exposure time was extended to 90s, only Escherichia coli, Coliforms, Aeromonas sp., Vibrio sp., and Pseudomonas putida survived. Only E. coli, Aeromonas sp., Vibrio sp. and P. putida survived treatment at 81.94 mA for 90s. Conversely, all bacterial groups were completely eliminated by treatment at 85.34 mA for either 60 or 90s. Dominant bacterial groups in leather processing wastewater also changed greatly upon exposure to plasma at 75.5 mA for 30 or 60s, with Enterobacter aerogenes, Klebsiella sp., Pseudomonas stutzeri and Acidithiobacillus ferrooxidans being sensitive to and eliminated from the community. At 90s of exposure, all groups were affected except for Pseudomonas sp. and Citrobacter freundii.

  5. Deterioration to extinction of wastewater bacteria by non-thermal atmospheric pressure air plasma as assessed by 16S rDNA-DGGE fingerprinting.

    Science.gov (United States)

    El-Sayed, Wael S; Ouf, Salama A; Mohamed, Abdel-Aleam H

    2015-01-01

    The use of cold plasma jets for inactivation of a variety of microorganisms has recently been evaluated via culture-based methods. Accordingly, elucidation of the role of cold plasma in decontamination would be inaccurate because most microbial populations within a system remain unexplored owing to the high amount of yet uncultured bacteria. The impact of cold atmospheric plasma on the bacterial community structure of wastewater from two different industries was investigated by metagenomic-based polymerase chain reaction-denaturing gradient gel electrophoresis (DGGE) utilizing 16S rRNA genes. Three doses of atmospheric pressure dielectric barrier discharge plasma were applied to wastewater samples on different time scales. DGGE revealed that the bacterial community gradually changed and overall abundance decreased to extinction upon plasma treatment. The bacterial community in food processing wastewater contained 11 key operational taxonomic units that remained almost completely unchanged when exposed to plasma irradiation at 75.5 mA for 30 or 60 s. However, when exposure time was extended to 90 s, only Escherichia coli, Coliforms, Aeromonas sp., Vibrio sp., and Pseudomonas putida survived. Only E. coli, Aeromonas sp., Vibrio sp., and P. putida survived treatment at 81.94 mA for 90 s. Conversely, all bacterial groups were completely eliminated by treatment at 85.34 mA for either 60 or 90 s. Dominant bacterial groups in leather processing wastewater also changed greatly upon exposure to plasma at 75.5 mA for 30 or 60 s, with Enterobacter aerogenes, Klebsiella sp., Pseudomonas stutzeri, and Acidithiobacillus ferrooxidans being sensitive to and eliminated from the community. At 90 s of exposure, all groups were affected except for Pseudomonas sp. and Citrobacter freundii. The same trend was observed for treatment at 81.94 mA. The variability in bacterial community response to different plasma treatment protocols revealed that plasma had a selective impact on bacterial

  6. The treatment application of acute cardiogenic pulmonary edema with BiPAP noninvasive positive air pressure ventilation%BiPAP无创通气在急性心源性肺水肿救治中的应用

    Institute of Scientific and Technical Information of China (English)

    黄玉蓉; 王晓园; 张海涛; 李玮; 白会云

    2012-01-01

    目的 探讨双水平正压无创机械通气在救治急性心源性肺水肿患者中的疗效.方法 将我科收治的59例急性心源性肺水肿患者随机分为两组:在常规利尿、扩血管、强心和镇静治疗的基础上,治疗组26例经BiPAP无创通气治疗;而对照组33例则给予高浓度面罩吸氧,观察两组治疗前后心率、呼吸频率、血气分析指标及临床征象的变化,评价治疗效果.结果 治疗组无创正压通气2 h后患者心率(HR)、呼吸频率(RR)明显减慢(P<0.05),收缩压(ABP)及舒张压(DBP)明显下降(P<0.01),血氧饱和度(SaO2)明显升高(P<0.01).结论 BiPAP无创通气治疗急性心源性肺水肿起效快,能明显改善低氧血症,是抢救急性心源性肺水肿的重要方法之一,值得临床推广.%Objective To evaluate the effects of BiPAP noninvasive positive ah- pressure ventilation on acute cardiogenic pulmo nary edema. Methods Fifty-nine patients with acute cardiogenic pulmonary edema were randomly divided into two groups: 26 patients in treatment group received BiPAP, while 33 patients in control groups had high concentration oxygen mask. All the patients received conven tional treatments including diuresis, cardiac stimulant, and sedation. Results Two hours after BiPAP, the patients' heart rate and breathing rate slowed down obviously ( P<0.05 ), and their systolic pressure and diastolic pressure declined dearly ( P <0. 01 ). Be sides , the oxygen saturation of blood rose obviously ( P < 0. 01 ). Conclusion BiPAP noninvasive positive air pressure ventilation can im prove meionectic blood better and take into effect quickly. Therefore it is an important means to rescue acute pulmonary edema and wouth to popularize.

  7. 30 CFR 56.13011 - Air receiver tanks.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Air receiver tanks. 56.13011 Section 56.13011... § 56.13011 Air receiver tanks. Air receiver tanks shall be equipped with one or more automatic pressure... the maximum allowable working pressure in a receiver tank by not more than 10 percent. Air...

  8. High-Compression-Ratio; Atkinson-Cycle Engine Using Low-Pressure Direct Injection and Pneumatic-Electronic Valve Actuation Enabled by Ionization Current and Foward-Backward Mass Air Flow Sensor Feedback

    Energy Technology Data Exchange (ETDEWEB)

    Harold Schock; Farhad Jaberi; Ahmed Naguib; Guoming Zhu; David Hung

    2007-12-31

    This report describes the work completed over a two and one half year effort sponsored by the US Department of Energy. The goal was to demonstrate the technology needed to produce a highly efficient engine enabled by several technologies which were to be developed in the course of the work. The technologies included: (1) A low-pressure direct injection system; (2) A mass air flow sensor which would measure the net airflow into the engine on a per cycle basis; (3) A feedback control system enabled by measuring ionization current signals from the spark plug gap; and (4) An infinitely variable cam actuation system based on a pneumatic-hydraulic valve actuation These developments were supplemented by the use of advanced large eddy simulations as well as evaluations of fuel air mixing using the KIVA and WAVE models. The simulations were accompanied by experimental verification when possible. In this effort a solid base has been established for continued development of the advanced engine concepts originally proposed. Due to problems with the valve actuation system a complete demonstration of the engine concept originally proposed was not possible. Some of the highlights that were accomplished during this effort are: (1) A forward-backward mass air flow sensor has been developed and a patent application for the device has been submitted. We are optimistic that this technology will have a particular application in variable valve timing direct injection systems for IC engines. (2) The biggest effort on this project has involved the development of the pneumatic-hydraulic valve actuation system. This system was originally purchased from Cargine, a Swedish supplier and is in the development stage. To date we have not been able to use the actuators to control the exhaust valves, although the actuators have been successfully employed to control the intake valves. The reason for this is the additional complication associated with variable back pressure on the exhaust valves when

  9. Determination of octanol-air partition coefficients and supercooled liquid vapor pressures of PAHs as a function of temperature: Application to gas-particle partitioning in an urban atmosphere

    Science.gov (United States)

    Odabasi, Mustafa; Cetin, Eylem; Sofuoglu, Aysun

    Octanol-air partition coefficients ( KOA) for 14 polycyclic aromatic hydrocarbons (PAHs) were determined as a function of temperature using the gas chromatographic retention time method. log KOA values at 25° ranged over six orders of magnitude, between 6.34 (acenaphthylene) and 12.59 (dibenz[ a,h]anthracene). The determined KOA values were within factor of 0.7 (dibenz[ a,h]anthracene) to 15.1 (benz[ a]anthracene) of values calculated as the ratio of octanol-water partition coefficient to dimensionless Henry's law constant. Supercooled liquid vapor pressures ( PL) of 13 PAHs were also determined using the gas chromatographic retention time technique. Activity coefficients in octanol calculated using KOA and PL ranged between 3.2 and 6.2 indicating near-ideal solution behavior. Atmospheric concentrations measured in this study in Izmir, Turkey were used to investigate the partitioning of PAHs between particle and gas-phases. Experimental gas-particle partition coefficients ( Kp) were compared to the predictions of KOA absorption and KSA (soot-air partition coefficient) models. Octanol-based absorptive partitioning model predicted lower partition coefficients especially for relatively volatile PAHs. Ratios of measured/modeled partition coefficients ranged between 1.1 and 15.5 (4.5±6.0, average±SD) for KOA model. KSA model predictions were relatively better and measured to modeled ratios ranged between 0.6 and 5.6 (2.3±2.7, average±SD).

  10. 120kV下常压空气纳秒脉冲电晕放电特性%Characteristic of nanosecond-pulsed corona discharge at 120 kV in atmospheric-pressure air

    Institute of Scientific and Technical Information of China (English)

    章程; 邵涛; 许家雨; 马浩; 徐蓉; 严萍

    2012-01-01

    With an excitation of negative repetitive pulses of 15 ns rise time and 30 to 40 ns duration, corona discharge in nanosecond-pulse regime at 120 kV in atmospheric-pressure air is experimentally investigated, and the characteristic of nanosecond-pulsed corona discharge is analyzed by the measurement of electrical discharge parameters, images and X-ray emission. The results show that X-ray emission occurs in nanosecond-pulsed corona discharge, but the intensity is weak. The counts of X rays decrease with the air gap spacing but increase with the pulse repetition frequency. In addition, owing to the fact that the residual particles in the gap enhance the local electric field when the next pulse is applied, separated corona channels are easily obtained at high pulse repetition frequency.%使用上升沿15 ns、脉宽30~40 ns的重复频率纳秒脉冲电源对120 kV下大气压空气中管-板电极结构电晕放电进行了实验研究,通过电压电流测量、放电图像拍摄和X射线探测分析了纳秒脉冲电晕放电特性.结果表明:纳秒脉冲电晕放电中存在X射线辐射,但辐射强度较弱,X射线辐射计数随着气隙距离的增大而减少,随着脉冲重复频率的增大而增多;放电空间的残余电荷加强了下一个脉冲到来时的局部电场,从而导致高重复频率下易于出现分散的电晕通道.

  11. Experimental study on thermal balance performance of naturally aspirated diesel engine at high altitude (low air pressure)%自然吸气柴油机高海拔(低气压)热平衡试验研究

    Institute of Scientific and Technical Information of China (English)

    董素荣; 许翔; 任晓江; 关立哲; 郑智; 刘瑞林

    2011-01-01

    基于内燃机高海拔(低气压)热平衡模拟试验台,对某型内燃叉车自然吸气柴油机进行了热平衡高原模拟试验,研究了柴油机燃烧放热量分配、冷却液温度以及排气温度等随海拔高度(大气压力)的变化规律.结果表明:随着海拔的升高,转化为有效功的热量、冷却水散热量以及排气带走的热量均不断下降,柴油机不完全燃烧造成的热损失、机体散失的热量以及其他热损失所占比重不断增加;与平原相比,海拔5 000 m时,转化为有效功的热量平均下降了13.79%,冷却水散热量平均下降了2.27%,排气带走的热量平均下降了14.4%,发动机的热平衡性能与平原相比发生了较大的变化.%The thermal balance performance of naturally aspirated forklift diesel engine at different altitudes was studied on the engine thermal balance test bed for simulating with high altitude (low air pressure). Influence of atmospheric pressure on the heat distribution, coolant temperature and exhaust gas temperature were analyzed. Results show that thermal changed into usable power, thermal carried by cooling water and exhaust gas decreased with the increase of altitude. On the contrary, the heat loss due to incomplete combustion increased with the increase of altitude. Compared with that at 5 000 m altitude, thermal changed into usable power decreased by 13. 79%; thermal carried by cooling water decreased by 2. 27%; thermal carried by exhaust air decreased by 14.4%. The thermal balance performance at high altitude is different from the performance at sea level.

  12. Air Leakage and Air Transfer Between Garage and Living Space

    Energy Technology Data Exchange (ETDEWEB)

    Rudd, A.

    2014-09-01

    This research project focused on evaluation of air transfer between the garage and living space in a single-family detached home constructed by a production homebuilder in compliance with the 2009 International Residential Code and the 2009 International Energy Conservation Code. The project gathered important information about the performance of whole-building ventilation systems and garage ventilation systems as they relate to minimizing flow of contaminated air from garage to living space. A series of 25 multi-point fan pressurization tests and additional zone pressure diagnostic testing characterized the garage and house air leakage, the garage-to-house air leakage, and garage and house pressure relationships to each other and to outdoors using automated fan pressurization and pressure monitoring techniques. While the relative characteristics of this house may not represent the entire population of new construction configurations and air tightness levels (house and garage) throughout the country, the technical approach was conservative and should reasonably extend the usefulness of the results to a large spectrum of house configurations from this set of parametric tests in this one house. Based on the results of this testing, the two-step garage-to-house air leakage test protocol described above is recommended where whole-house exhaust ventilation is employed. For houses employing whole-house supply ventilation (positive pressure) or balanced ventilation (same pressure effect as the Baseline condition), adherence to the EPA Indoor airPLUS house-to-garage air sealing requirements should be sufficient to expect little to no garage-to-house air transfer.

  13. Picosecond delays of light emitted by streamer in atmospheric pressure air: analysis of N2(C3{\\Pi}u) and N+2 (B2{\\Sigma}+u) emissions and fundamental streamer structure

    CERN Document Server

    Hoder, Tomas; Bourdon, Anne; Simek, Milan

    2014-01-01

    Both experimental and theoretical analysis of ultra-short phenomena occurring dur- ing the positive streamer propagation in atmospheric pressure air is presented. It is shown that as the streamer passes a spatial coordinate, emission maxima from radiative states with different excitation energies follow with different delays. Associating the po- sition of the streamer head with the maximum value of the self-enhanced electric field, a maximum delay of 220 ps was experimentally found for the peak emission of the second positive system of molecular nitrogen. On a later stage of streamer development this delay can reach as much as 400 ps. Different delays for first negative and second positive systems emission maxima are caused by differences in the dynamics of populating the radiative states, due to different excitation rates. It is shown that emission maxima delays linearly depend on the ratio of streamer radius and its velocity. This is found to be one of the fundamental features of the streamer structure and ...

  14. Vacuum exhaust process in vacuum pressure-swing adsorption for upgrading ventilation air methane%真空变压吸附提浓煤矿乏风瓦斯的抽真空排放过程

    Institute of Scientific and Technical Information of China (English)

    张传钊; 刘应书; 李永玲; 杨雄; 孟宇

    2013-01-01

    The equilibrium adsorption characteristics of activated carbon were tested and researched. Equilibrium selectivity of the activated carbon was 5. 20. Vacuum exhaust process in three-bed vacuum pressure swing adsorption (VPSA) for concentrating ventilation air methane (VAM) was studied experimentally. The effect of vacuum exhaust ratio on methane concentration and recovery were investigated. The factors which effect on vacuum exhaust process were analyzed. The results show that vacuum exhaust step can increase the methane concentration of product gas without increasing pressure. As the ratio increases, the concentrations of methane in both product and effluent first increase , and then reach steady state after a certain vacuum exhaust ratio. At the same time, methane recovery is decreased. The pressure equalizing processes and adsorption pressure have obvious effect on the vacuum exhaust process. The process of vacuum exhaust gas recovered can increase methane recovery, but not always increase the methane content of the product gas, there is a critical vacuum exhaust ratio, it will decrease the methane concentration of product when the vacuum exhaust ratio is lower than this value. This process of vacuum exhaust gas recovered can enrich the methane concentration from 0. 2% to 0. 680% with the adsorption and desorption pressure of 140 kPa and 14 kPa. The results could provide reference for the industrial application in VAM enrichment.%研究了活性炭的平衡吸附性能,计算出该种活性炭对甲烷和氮气的混合气体的分离因子为5.20,并采用以该种活性炭为吸附剂的三塔真空变压吸附装置,研究了循环流程中的抽排步骤对吸附分离效果的影响,并分析了影响抽排过程的因素.结果表明:引入抽排步骤可以在不改变吸附与解吸压力的情况下有效提高产品气中甲烷浓度.而甲烷浓度会随抽排比的增加而增加,但存在一个极限值,达到极限值之后趋于稳定.与此同

  15. 某水电站油压装置自动补气超时问题的分析及处理%Analysis and Treatment of the Overtime Problem in Automatic Air Supplement of Oil Pressure Device in a Hydropower Station

    Institute of Scientific and Technical Information of China (English)

    郭守峰

    2015-01-01

    The structure and working principles of an automatic air supplement unit are introduced, which is adopted in the oil pressure device of the generator governor in a hydropower station.The overtime problem of the air supplement process occurred in the automatic air supplement unit is analyzed.Based on the analysis, the overtime problem is solved by optimization of the automatic air supplement parameters.%介绍了某水电站调速器油压装置自动补气装置组成、原理,并对该电站出现的自动补气装置补气超时现象的原因进行了分析,结合实际,通过自动补气参数的优化,自动补气超时现象消除。

  16. Hexane Air Combustion

    CERN Document Server

    Boettcher, Philipp A; Shepherd, Joseph E

    2010-01-01

    Hot surface ignition and subsequent flame propagation of premixed n-hexane air mixtures are shown in this fluid dynamics video. High speed schlieren photography revealed 3 distinct behaviors of ignition and propagation as a function of mixture composition and initial pressure.

  17. Considering Air Density in Wind Power Production

    CERN Document Server

    Farkas, Zénó

    2011-01-01

    In the wind power production calculations the air density is usually considered as constant in time. Using the CIPM-2007 equation for the density of moist air as a function of air temperature, air pressure and relative humidity, we show that it is worth taking the variation of the air density into account, because higher accuracy can be obtained in the calculation of the power production for little effort.

  18. Pressurized Submarine Rescue

    Science.gov (United States)

    1984-06-07

    The atmosphere components can be divided into nitrogen , oxygen, carbon dioxide and contaminates. i. Nitrogen . Nitrogen causes narcosis in a dose...compared with 80% helium 20% oxygen. The narcosis increases as the pressure increases to where debilitation occurs above about 8 ATA (9.3 ATA nitrogen ...when breathing air. Nitrogen narcosis is relatively mild at 5 ATA, and although decrements in performance can be measured in a laboratory setting (19

  19. A Tire Air Maintenance Technology

    Science.gov (United States)

    Pierce, Alan

    2012-01-01

    Improperly inflated car tires can reduce gas mileage and car performance, speed up tire wear, and even cause a tire to blow out. The AAA auto club recommends that someone check the air pressure of one's car's tires at least once a month. Wouldn't it be nice, though, if someone came up with a tire pressure-monitoring system that automatically kept…

  20. Air Leakage and Air Transfer Between Garage and Living Space

    Energy Technology Data Exchange (ETDEWEB)

    Rudd, Armin [Building Science Corporation, Westford, MA (United States)

    2014-09-01

    This research project focused on evaluation of air transfer between the garage and living space in a single-family detached home constructed by a production homebuilder in compliance with the 2009 International Residential Code and the 2009 International Energy Conservation Code. The project gathered important information about the performance of whole-building ventilation systems and garage ventilation systems as they relate to minimizing flow of contaminated air from garage to living space. A series of 25 multi-point fan pressurization tests and additional zone pressure diagnostic testing characterized the garage and house air leakage, the garage-to-house air leakage, and garage and house pressure relationships to each other and to outdoors using automated fan pressurization and pressure monitoring techniques. While the relative characteristics of this house may not represent the entire population of new construction configurations and air tightness levels (house and garage) throughout the country, the technical approach was conservative and should reasonably extend the usefulness of the results to a large spectrum of house configurations from this set of parametric tests in this one house. Based on the results of this testing, the two-step garage-to-house air leakage test protocol described above is recommended where whole-house exhaust ventilation is employed.

  1. 基于歧管压力表法对A30-10汽车空调实验台制冷故障的诊断分析%A Diagnostic Analysis of A30-10 Automotive Air Conditioning Experiment Table Refrigeration Fault Based on Manifold Pressure Gauge

    Institute of Scientific and Technical Information of China (English)

    江四; 孟杰

    2012-01-01

      In the air conditioning maintenance, fault diagnosis and detection, using manifold pressure gauge to make an analysis of refrigeration cycle fault is one of the most effective measures. With manifold pressure gauge the system can make the smelting device turn from high voltage side pressure to low voltage side pressure re⁃spectively with instrument instructions, which can determine the causes of the fault in order to use the right de⁃bugging methods. Based on the manifold pressure gauge method, a diagnostic analysis of A30-10 automotive air conditioning experiment table refrigeration fault is introduced in this paper.%  用歧管压力表能把制冷装置的高压侧与低压侧的压力分别用仪表指示出来,从而大致判定出故障的原因。本文采用歧管压力表法对A30-10汽车空调实验台进行了制冷故障的诊断分析。

  2. 变频空调中翅片管蒸发器换热与压降特性%Heat transfer and pressure drop characteristics of fin - and - tube evaporators in variable frequency air- condition system

    Institute of Scientific and Technical Information of China (English)

    刘金平; 祁元龙; 邹永胜

    2011-01-01

    通过试验研究了变频空调系统中翅片管蒸发器管内外侧换热与压降特性,分析了压缩机频率对波纹翅片和百叶窗翅片管蒸发器管内沸腾换热系数、空气侧换热因子和摩擦因子的影响.结果表明:随着压缩机频率的增加,两种翅片的管内沸腾换热系数hi均增加;摩擦因子f都减小,百叶窗翅片的摩擦因子f是波纹翅片的2倍多;换热因子j随着压缩机频率增加而减小,波纹翅片的j因子随Re数变化明显,百叶窗翅片的则变化不大.%The heat transfer and pressure drop characteristics of outside and inside of the fin - and - tube evaporators in variable frequency air - condition system were studied. The effects of compressor frequency on inside boiling heat transfer coefficient, airside heat transfer factor and friction factor of wavy fin and louver fin were investigated. The results indicated that with the increase of compressor frequency, the boiling heat transfer coefficients in two - phase region of two fins increased. The friction factors f of both fins decreased, and the factor f of louver fin almost was two times higher than that of wavy fin. The factors j of the two fins also decreased and the factor j of wavy fin changed obviously than louver fin with the variety of Re number.

  3. 大尺寸大气压空气等离子体射流设备研究%A Large Scale Air Plasma Jet Device at Atmospheric Pressure

    Institute of Scientific and Technical Information of China (English)

    李森; 吴立; 徐凯; 顾璠

    2015-01-01

    A specially designed device to generate large scale plasma jet at atmospheric pressure is reported. The device is a modified dielectric barrier discharge with a high polymer film as dielectric. It is capable of generating a plasma jet with the diameter up to 28 mm and the length up to several tens mm in the surrounding air. There are various excited plasma species shown through optical emission spectrum. The jet temperature is close to room temperature. Therefore, this device may be used for some applications such as the decontamination of temperature-sensitive materials, surface modification, etc.%本文提出了一种特殊的大尺寸大气压空气等离子体射流设备。该设备采用一种高分子耐高温涂料作为介质进行放电,通过气体渐扩通道,产生大尺寸空气等离子体射流,射流直径最宽处可以达到28 mm,长度可以达到数十mm。本文对射流中的活性物质进行光谱测量,同时对射流宏观温度进行测量,指出该射流温度非常接近室温,可以用于温度敏感材料的表面处理等方面。

  4. Air pocket removal from downward sloping pipes

    NARCIS (Netherlands)

    Pothof, I.W.M.; Clemens, F.H.L.R.

    2012-01-01

    Air-water flow is an undesired condition in water pipelines and hydropower tunnels. Water pipelines and wastewater pressure mains in particular are subject to air pocket accumulation in downward sloping reaches, such as inverted siphons or terrain slopes. Air pockets cause energy losses and an assoc

  5. Clinical study of XIR (extreme infrared) cold and warm air mattress used for pre-vention and control ofⅠandⅡperiods of pressure ulcers in ICU patients with high risk of pressure ulcers%远红外线冷暖气流床垫在 ICU压疮高危患者Ⅰ、Ⅱ期压疮防治中的应用效果

    Institute of Scientific and Technical Information of China (English)

    张允; 朱滨; 陈建芬; 庄细琴; 王亚芳

    2015-01-01

    Objective To explore the effect of XIR cold and warm air mattress used for prevention and control ofⅠandⅡperiods of pressure ulcers in ICU high risk patients of pressure ulcers and provide care references to reduce the incidence of pressure ulcers of the ICU patients with high risk of pressure ulcers and improve pressure ulcer cure rate.Methods 356 cases with high risk of pressure ulcers who were admitted to ICU during January 2010 to December 2011 were selected and randomly divided into observation ( n=186 ) and control ( n=170) groups.XIR cold and warm air mattress was used in observation group and patients in observation group were changed body posi-tion every four hours.The results were compared.Results The pressure ulcer rate of observation group was 13.4%, lower than that of con-trol group (21.8%), the difference was statistically significant.Conclusion XIR cold and warm air mattress could effectively prevent and control pressure ulcers for the ICU patients with high risk of pressure ulcers, it is an effective way to prevent and control pressure ulcers.%目的:探讨远红外线冷暖气流床垫预防和治疗ICU压疮高危患者Ⅰ、Ⅱ期压疮的效果。方法将我院ICU 2010年1月至2011年12月收治的356例压疮患者,随机分为观察组186例和对照组170例,给予观察组患者使用远红外线冷暖气流床垫,4 h翻身1次。比较两组防治效果。结果观察组患者压疮发生率为13.4%,低于对照组21.8%,差异有统计学意义( P<0.05);观察组患者Ⅰ、Ⅱ期压疮愈合率为95.8%,高于对照组70.6%,差异有统计学意义(P<0.05)。结论远红外线冷暖气流床垫防治压疮效果显著,为ICU压疮高危患者有效防治压疮的方法,降低了ICU压疮高危患者的压疮发生率,提高了压疮治愈率。

  6. Peer Pressure

    Science.gov (United States)

    ... who are unsure of themselves, new to the group, or inexperienced with peer pressure may also be more likely to give in. ... stand that makes you look uncool to your group. But these situations can be ... up to peer pressure, but it does take courage — yours: Listen to ...

  7. Air Consumption Analysis of Air-Jet Weaving

    Directory of Open Access Journals (Sweden)

    RAJ KUMAR KHIANI

    2016-07-01

    Full Text Available In Textile industry, production is mostly key concern for Industry owner. This always has attracted researchers and machines manufacturers to make new developments in process and machines. Air-jet is one of the leading and successful highest productive weaving machines. However, it is now well established that due to add of charges of compressed air, manufacturing cost of air-jet weaving machine is higher as compared with rapier and projectile weaving machines. This is why countries having energy issues do not prefer air-jet weaving machines comparing projectile weaving machines. In this regard, several researchers and machine manufacturers have continuously been working to improve the efficiency of air-jet weft insertion. However, industry practice is as important as design made by researchers. The aim of this research is to investigate the air consumption of air-jet weaving on industrial scale practice. In this study, five weaving machine of same manufacturer and model were selected. It was observed that despite of manufacturing same quality of fabric, air consumption was varying almost in all weaving machines. Conventionally, mill workers adopt hit and trial practice in weaving industry including airpressure setting which leads to variation of nozzle pressure. Main reason of disparity of air consumption in air-jet weaving machines may be variation of distance from compressor to weaving machines, number of joints, un-necessary valve opening and pipes leakages cause an increase of compressed air consumption.

  8. Characteristics of atmospheric pressure air uniform discharge generated by a plasma needle%大气压等离子体针产生空气均匀放电特性研究

    Institute of Scientific and Technical Information of China (English)

    李雪辰; 袁宁; 贾鹏英; 常媛媛; 嵇亚飞

    2011-01-01

    Cold plasma generated by atmospheric air discharge has wide application prospect in industry because it does not need vacuum equipment and mass production is possible.In this paper,a stable uniform discharge is generated in open air by a plasma needle.Discharge mechanism is investigated by optical method,and plasma parameters are given by the spatially resolved measurement of emission spectrum from the discharge.Results show that the discharges have two modes.One is a corona discharge mode and the other is plasma plume mode.In the stable plasma plume mode,a strong emission area and a weak emission one can be distinguished from each other.The development velocity of the weak emission area is much faster than that of the strong emission area.Furthermore,the electron energy and the plasma density in the weak emission area are also bigger than those in the strong emission area.Therefore,the discharge in the strong emission area is dominated by Townsend mechanism,while that in the weak emission area is dominated by streamer discharge.Gas temperature and vibration temperature are also studied in this paper.The experimental results are of great importance to the industrial applications of atmospheric pressure discharge.%大气压空气放电由于脱离了真空装置,易于实现流水线生产,因而在工业上具有广泛的应用.采用等离子体针装置在空气中产生了稳定的大气压均匀放电.利用光谱法对等离子体的相关参数进行了空间分辨率测量,并通过光学方法对放电机理进行了研究.结果表明,等离子体针产生的放电存在电晕放电和等离子体羽放电两种模式.在稳定的等离子体羽放电模式中,发光分为强光区和弱光区.弱光区放电的发展速度远大于强光区的发展速度,电子能量和电子密度均是弱光区比强光区大.对均匀放电的气体温度和振动温度的研究表明,强光区放电遵循汤生击穿机理而弱光区为流光放电.这些结果对

  9. Over-pressurized bioreactors: application to microbial cell cultures.

    Science.gov (United States)

    Lopes, Marlene; Belo, Isabel; Mota, Manuel

    2014-01-01

    In industrial biotechnology, microbial cultures are exposed to different local pressures inside bioreactors. Depending on the microbial species and strains, the increased pressure may have detrimental or beneficial effects on cellular growth and product formation. In this review, the effects of increased air pressure on various microbial cultures growing in bioreactors under moderate total pressure conditions (maximum, 15 bar) will be discussed. Recent data illustrating the diversity of increased air pressure effects at different levels in microbial cells cultivation will be presented, with particular attention to the effects of oxygen and carbon dioxide partial pressures on cellular growth and product formation, and the concomitant effect of oxygen pressure on antioxidant cellular defense mechanisms.

  10. Practical application of pressure regulating technology for fire district in Meiyukou Coal Mine

    Institute of Scientific and Technical Information of China (English)

    ZHANG Qing-feng; JIA Bao-shan

    2008-01-01

    Based on the simulated laboratory experiment of pressure balance for fire ex-tinguishing, the pressure regulating technology was summarized for the fire district in Meiyukou Coal Mine. The technology includes three measures for air pressure regulation, namely applying the pressure regulating chamber to balance the air pressure of fire district, increasing the air pressure of the working face, and filling the ground surface fractures. A good effect was obtained to prevent and extinguish the fire. When the measures fail to in-crease the pressure of working face or to regulate that of air chamber, the measure to fill the ground surface fractures will play an important role.

  11. Practical application of pressure regulating technology for fire district in Meiyukou Coal Mine

    Institute of Scientific and Technical Information of China (English)

    ZHANG Qing-feng; JIA Bao-shan

    2008-01-01

    Based on the simulated laboratory experiment of pressure balance for fire extinguishing,the pressure regulating technology was summarized for the fire district in Meiyukou Coal Mine.The technology includes three measures for air pressure regulation,namely applying the pressure regulating chamber to balance the air pressure of fire district,increasing the air pressure of the working face,and filling the ground surface fractures.A good effect was obtained to prevent and extinguish the fire.When the measures fail to increase the pressure of working face or to regulate that of air chamber,the measure to fill the ground surface fractures will play an important role.

  12. Continuous monitoring of barometric pressure in deep mines

    Energy Technology Data Exchange (ETDEWEB)

    Trutwin, W.; Mironowicz, W.; Wasilewski, S.; Krawczyk, J. [Research and Development Centre for Electrical Engineering and Automation in Mining EMAG, Katowice (Poland)

    2005-07-01

    Barometric pressure and its variation in deep underground workings have a considerable effect on ventilation conditions. Pressure changes which create transient states of air flow and air parameters in workings are especially significant. Experiments have shown that pressure changes have a remarkable effect on air parameters at mine workings. Continuous monitoring of the barometric pressure on the surface of mines allows for the detection of changes in pressure which influence alternations of pressure in the underground areas of mines. Important factors are the internal disturbances of pressure within a mine ventilation system due to variable conditions of fan operation and the operation of a winding machine where a mine cage moving in a shaft causes piston like disturbances. Local transient disturbances caused by temporary opening/closing of air stoppings due to personnel or underground transport traffic are of importance. The results of over two years of observations of barometric pressure and its influence on pressure variation in underground mine workings are presented. The observations were possible through the installation of pressure sensors at selected points of the downcast shaft in a mine. Of interest are the observations of the transient states of pressure and other air parameters caused by emergency fan stoppage, movement of a mine cage and changes due to the opening of air stoppings. Data acquired during experiments of opening and closing air stoppings were used for the validation of a flow model in a long working. 13 refs., 15 figs.

  13. Pressure Sores

    Science.gov (United States)

    ... injury. Some chronic diseases, such as diabetes and hardening of the arteries, make it hard for pressure ... Use a mild soap and warm (not hot) water. Apply moisturizers so your skin doesn’t get ...

  14. Pressure difference receiving ears

    DEFF Research Database (Denmark)

    Michelsen, Axel; Larsen, Ole Næsbye

    2007-01-01

    of such pressure difference receiving ears have been hampered by lack of suitable experimental methods. In this review, we review the methods for collecting reliable data on the binaural directional cues at the eardrums, on how the eardrum vibrations depend on the direction of sound incidence, and on how sound...... waves behave in the air spaces leading to the interior surfaces of eardrums. A linear mathematical model with well-defined inputs is used for exploring how the directionality varies with the binaural directional cues and the amplitude and phase gain of the sound pathway to the inner surface...

  15. Barotrauma: Tooth Under Pressure.

    Science.gov (United States)

    Kumar, Satheesh; Kumar, Preeti Satheesh; John, Jins; Patel, Ruchi

    2015-11-01

    With the growing number of air passengers, flight attendants, leisure pilots, as well as military and airline pilots, dentists may encounter physiological and pathological phenomena precipitated by high altitude. With the introduction of the self-contained breathing apparatus (SCUBA), many of these manifestations caused by changes in atmospheric pressure were reported in association with diving as well. Limited literature exists on this subject. Hence, this article aims to review literature concerning the classification, etiology and manifestations of barodontalgia, as well as important clinical considerations for its management.

  16. Lateral pressure profiles in lipid monolayers

    NARCIS (Netherlands)

    Baoukina, Svetlana; Marrink, Siewert J.; Tieleman, D. Peter

    2010-01-01

    We have used molecular dynamics simulations with coarse-grained and atomistic models to study the lateral pressure profiles in lipid monolayers. We first consider simple oil/air and oil/water interfaces, and then proceed to lipid monolayers at air/water and oil/water interfaces. The results are qual

  17. Air Cleaning Technologies

    Science.gov (United States)

    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

  18. 深圳地铁11号线隧道空气压力波研究%Study on Air Pressure Waves in Tunnels on Shenzhen Metro Line 11

    Institute of Scientific and Technical Information of China (English)

    张海天; 陈健

    2011-01-01

    The article proposes pressure comfort standards in high-speed metro tunnels. By using the tunnel pressure wave analysis software ThermoTun, authors analyzed tunnel pressure waves and comfort of pressure considering different section design for tunnels on Shenzhen metro line 11. They also put forward design proposals for tunnel pressure relief system and tunnel profile.%分析并提出高速地铁隧道压力舒适度标准.采用隧道压力波分析软件ThermoTun,对深圳地铁11号线隧道段不同断面设计情况下的压力波及压力舒适度进行分析,提出对隧道泄压系统及隧道断面的设计建议.

  19. Determinants of skin contact pressure formation during non-invasive ventilation.

    Science.gov (United States)

    Dellweg, Dominic; Hochrainer, Dieter; Klauke, Matthias; Kerl, Jens; Eiger, Glenn; Kohler, Dieter

    2010-03-01

    There is no published data about mask features that impact skin contact pressure during mask ventilation. To investigate the physical factors of skin contact pressure formation. We measured masks with original and reduced air cushion size and recorded contact pressure. We determined cushion contact and mask areas by planimetric measurements. Contact pressures necessary to prevent air leakage during inspiration exceed inspiratory pressure by 1.01+/-0.41 hPa independent of cushion size. Contact area, ventilator pressure and mask area during inspiration and expiration impact contact pressure. Mask contact pressures are higher during expiration. The contact pressure increases with increase in inspiratory pressures independent of the ventilator cycle. During expiration, the contact pressure will increase in proportion to the expiratory pressure reduction of the ventilator. The mask with reduced air cushion size developed higher contact pressures. Contact pressure can be reduced by selecting masks with a small mask area in combination with a large mask cushion.

  20. Nitrogen fluorescence in air for observing extensive air showers

    Directory of Open Access Journals (Sweden)

    Tsunesada Y.

    2013-06-01

    Full Text Available Extensive air showers initiate the fluorescence emissions from nitrogen molecules in air. The UV-light is emitted isotropically and can be used for observing the longitudinal development of extensive air showers in the atmosphere over tenth of kilometers. This measurement technique is well-established since it is exploited for many decades by several cosmic ray experiments. However, a fundamental aspect of the air shower analyses is the description of the fluorescence emission in dependence on varying atmospheric conditions. Different fluorescence yields affect directly the energy scaling of air shower reconstruction. In order to explore the various details of the nitrogen fluorescence emission in air, a few experimental groups have been performing dedicated measurements over the last decade. Most of the measurements are now finished. These experimental groups have been discussing their techniques and results in a series of Air Fluorescence Workshops commenced in 2002. At the 8th Air Fluorescence Workshop 2011, it was suggested to develop a common way of describing the nitrogen fluorescence for application to air shower observations. Here, first analyses for a common treatment of the major dependences of the emission procedure are presented. Aspects like the contributions at different wavelengths, the dependence on pressure as it is decreasing with increasing altitude in the atmosphere, the temperature dependence, in particular that of the collisional cross sections between molecules involved, and the collisional de-excitation by water vapor are discussed.

  1. Nitrogen fluorescence in air for observing extensive air showers

    Science.gov (United States)

    Keilhauer, B.; Bohacova, M.; Fraga, M.; Matthews, J.; Sakaki, N.; Tameda, Y.; Tsunesada, Y.; Ulrich, A.

    2013-06-01

    Extensive air showers initiate the fluorescence emissions from nitrogen molecules in air. The UV-light is emitted isotropically and can be used for observing the longitudinal development of extensive air showers in the atmosphere over tenth of kilometers. This measurement technique is well-established since it is exploited for many decades by several cosmic ray experiments. However, a fundamental aspect of the air shower analyses is the description of the fluorescence emission in dependence on varying atmospheric conditions. Different fluorescence yields affect directly the energy scaling of air shower reconstruction. In order to explore the various details of the nitrogen fluorescence emission in air, a few experimental groups have been performing dedicated measurements over the last decade. Most of the measurements are now finished. These experimental groups have been discussing their techniques and results in a series of Air Fluorescence Workshops commenced in 2002. At the 8th Air Fluorescence Workshop 2011, it was suggested to develop a common way of describing the nitrogen fluorescence for application to air shower observations. Here, first analyses for a common treatment of the major dependences of the emission procedure are presented. Aspects like the contributions at different wavelengths, the dependence on pressure as it is decreasing with increasing altitude in the atmosphere, the temperature dependence, in particular that of the collisional cross sections between molecules involved, and the collisional de-excitation by water vapor are discussed.

  2. Steerable percussion air drilling system

    Energy Technology Data Exchange (ETDEWEB)

    Bui, H.D.; Gray, M.A.; Oliver, M.S.

    1995-07-01

    In the Steerable Percussion Air Drilling System (SPADS), air percussion is used to drill directionally in hard formations. Compared to mud or air powered PDM motors, SPADS offers directional drilling at high penetration rate, reduced mud costs, negligible formation damage, and immediate indication of hole productivity. Field tests turned up problems ranging from tool design to operation procedures; remedies were developed. There is an optimum WOB (weight on bit) at which torque is reasonably low. The hammer was tested at three different line pressures (200, 300, 350 psig) at optimum WOB in granite, limestone, and sandstone.

  3. Plasma Air Decontamination System (PADS) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed Plasma Air Decontamination System (PADS) is a trace contaminant control device based on non-thermal atmospheric-pressure plasma technology. Compared to...

  4. Plasma Air Decontamination System (PADS) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed Plasma Air Decontamination System (PADS) is a trace contaminant control device based on non-thermal atmospheric pressure plasma technology that operates...

  5. Charcoal and activated carbon at elevated pressure

    Energy Technology Data Exchange (ETDEWEB)

    Antal, M.J. Jr.; Dai, Xiangfeng; Norberg, N. [Univ. of Hawaii at Manoa, Honolulu, HI (United States)] [and others

    1995-12-01

    High quality charcoal has been produced with very high yields of 50% to 60% from macadamia nut and kukui nut shells and of 44% to 47% from Eucalyptus and Leucaena wood in a bench scale unit at elevated pressure on a 2 to 3 hour cycle, compared to commercial practice of 25% to 30% yield on a 7 to 12 day operating cycle. Neither air pollution nor tar is produced by the process. The effects of feedstock pretreatments with metal additives on charcoal yield are evaluated in this paper. Also, the influences of steam and air partial pressure and total pressure on yields of activated carbon from high yield charcoal are presented.

  6. PRESSURE CHARACTERISTICS OF CAVITATION CONTROL BY AERATION

    Institute of Scientific and Technical Information of China (English)

    DONG Zhi-yong; LU Yang-quan; JU Wen-jie; CAI Xin-ming; DING Chun-sheng

    2005-01-01

    This experimental investigation was systematically conducted with the aid of a non-circulating water tunnel in the Hydraulics Laboratory at Zhejiang University of Technology in China.The test velocity is between 20m/s and 40m/s.The least air concentration to prevent cavitation erosion lies between 1.7% and 4.5%.Pressure waveforms with and without aeration in cavitation and cavitation erosion regions were measured.Time-averaged pressure profiles with and without aeration were compared.Pressure characteristics corresponding to least air concentration to prevent cavitation erosion in cavitation and cavitation erosion regions were analyzed.

  7. Changes in air flow patterns using surfactants and thickeners during air sparging: bench-scale experiments.

    Science.gov (United States)

    Kim, Juyoung; Kim, Heonki; Annable, Michael D

    2015-01-01

    Air injected into an aquifer during air sparging normally flows upward according to the pressure gradients and buoyancy, and the direction of air flow depends on the natural hydrogeologic setting. In this study, a new method for controlling air flow paths in the saturated zone during air sparging processes is presented. Two hydrodynamic parameters, viscosity and surface tension of the aqueous phase in the aquifer, were altered using appropriate water-soluble reagents distributed before initiating air sparging. Increased viscosity retarded the travel velocity of the air front during air sparging by modifying the viscosity ratio. Using a one-dimensional column packed with water-saturated sand, the velocity of air intrusion into the saturated region under a constant pressure gradient was inversely proportional to the viscosity of the aqueous solution. The air flow direction, and thus the air flux distribution was measured using gaseous flux meters placed at the sand surface during air sparging experiments using both two-, and three-dimensional physical models. Air flow was found to be influenced by the presence of an aqueous patch of high viscosity or suppressed surface tension in the aquifer. Air flow was selective through the low-surface tension (46.5 dyn/cm) region, whereas an aqueous patch of high viscosity (2.77 cP) was as an effective air flow barrier. Formation of a low-surface tension region in the target contaminated zone in the aquifer, before the air sparging process is inaugurated, may induce air flow through the target zone maximizing the contaminant removal efficiency of the injected air. In contrast, a region with high viscosity in the air sparging influence zone may minimize air flow through the region prohibiting the region from de-saturating.

  8. Development of energy-efficient comfortable ventilation systems with air quality guided volume flow control and continuous monitoring of the window opening status. Part 2. Theoretical investigations of the pressure difference method. Research project; Entwicklung energieeffizienter Komfortlueftungsanlagen mit luftqualitaetsgefuehrter Volumenstromregelung und kontinuierlicher Erfassung des Fensteroeffnungszustandes. Teilbericht 2. Theoretische Untersuchungen zur Druckdifferenz-Methode. Forschungsprojekt

    Energy Technology Data Exchange (ETDEWEB)

    Knissel, Jens; Grossklos, Marc [Institut Wohnen und Umwelt GmbH, Darmstadt (Germany); Werner, Johannes [Ingenieurbuero fuer Energieberatung, Haustechnik und Oekologische Konzepte GbR (eboek), Tuebingen (Germany)

    2011-05-15

    In energy-efficient buildings with mechanical ventilation and heat recovery, the heat losses of ventilation of a building can be influenced by additional open windows. This causes a significant rise in the heating demand. The Drd method (pressure difference method) assumes that the negative pressure in a building after switching off the supply air fan will depend on whether all windows are closed, or at least one window is open. In the research project under consideration the determination of the position of the window aperture using the Drd method shall be developed further. The operating conditions of the Drd method is investigated theoretically. Questions of the required building tightness and plant characteristics are clarified.

  9. Air Pollution

    Science.gov (United States)

    ... to view this content or go to source URL . What NIEHS is Doing on Air Pollution Who ... Junction Last Reviewed: February 06, 2017 This page URL: NIEHS website: https://www.niehs.nih.gov/ Email ...

  10. Blood pressure measurement

    Science.gov (United States)

    Diastolic blood pressure; Systolic blood pressure; Blood pressure reading; Measuring blood pressure ... or your health care provider will wrap the blood pressure cuff snugly around your upper arm. The lower ...

  11. Screening in humid air plasmas

    Science.gov (United States)

    Filippov, Anatoly; Derbenev, Ivan; Dyatko, Nikolay; Kurkin, Sergey

    2016-09-01

    Low temperature air plasmas containing H2O molecules are of high importance for atmospheric phenomena, climate control, biomedical applications, surface processing, and purification of air and water. Humid air plasma created by an external ionization source is a good model of the troposphere where ions are produced by the galactic cosmic rays and decay products of air and soil radioactive elements such as Rn222. The present paper is devoted to study the ionic composition and the screening in an ionized humid air at atmospheric pressure and room temperature. The ionization rate is varied in the range of 101 -1018 cm-3s-1. The humid air with 0 - 1 . 5 % water admixture that corresponds to the relative humidity of 0 - 67 % at the air temperature equal to 20°C is considered. The ionic composition is determined on the analysis of more than a hundred processes. The system of 41 non-steady state particle number balance equations is solved using the 4th order Runge-Kutta method. The screening of dust particle charge in the ionized humid air are studied within the diffusion-drift approach. The screening constants are well approximated by the inverse Debye length and characteristic lengths of recombination and attachment processes. This work was supported by the Russian Science Foundation, Project No. 16-12-10424.

  12. 49 CFR 232.217 - Train brake tests conducted using yard air.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Train brake tests conducted using yard air. 232... Train brake tests conducted using yard air. (a) When a train air brake system is tested from a yard air... reduction of brake pipe air pressure at the same, or slower, rate as an engineer's brake valve. (b) The...

  13. EFFECTS OF ENTRAINED AIR MANNER ON CAVITATION DAMAGE*

    Institute of Scientific and Technical Information of China (English)

    WU Jian-hua; LUO Chao

    2011-01-01

    Early in 1953 the experiments by Peterka proved that air entrainment has effects on decreasing cavitation damage. This technology has been widely used in the release works of high dams since the inception of air entrainment in the Grand Goulee Dam in 1960. Behavior, mechanism and application of air entrainment for cavitation damage control have been investigated for over half century. However, severe cavitation damage happened due to complex mechanism of air entrainment. The effects of air entrainment are related to many factors, including geometric parameters, hydraulic parameters and entrained air manners. In the present work an experimental set-up for air entrainment was specially designed, the behavior of reducing cavitation damage was experimentally investigated in the three aspects of entrained air pressure, air tube aera and air tube number. The results show that magnitude of reduction of cavitation damage is closely related to the entrained air tube number as well as entrained air pressure, air tube aera, and that the effect through three air tubes is larger than that through single air tube although the entrained air tubes have the same sum of tube aera, that is, 1 + 1 + 1 > 3. Therefore, it is important to design an effective manner of air entrainment.

  14. 全膝关节置换术后应用持续冷疗联合空气波气压治疗的护理效果观察%Nursing effect observation of continuous cryotherapy combined with air wave pressure treatment after total knee replacement

    Institute of Scientific and Technical Information of China (English)

    刘霞

    2015-01-01

    目的:探讨持续冷疗联合空气波气压治疗对全膝关节置换术后减轻关节肿痛的效果。方法120例行全膝关节置换术后患者,按入院先后顺序随机分为对照组和观察组,各60例。对照组采用cryu-cuff加压冷疗自动循环系统持续冷疗,观察组采用cryu-cuff加压冷疗自动循环系统联合空气波气压治疗,观察两组患者关节疼痛、肿胀程度。结果观察组关节疼痛程度、患侧关节肿胀值均低于对照组,差异均有统计学意义(P<0.05)。结论持续冷疗联合空气波气压治疗对全膝关节置换术后患者减轻关节肿痛有较好疗效,利于患者早期康复训练,有效促进关节功能恢复,值得临床推广。%Objective To explore the effect of continuous cryotherapy combined with air wave pressure treatment for relieving swelling and pain in joint after total knee replacement. Methods A total of 120 patients undergoing total knee replacement were randomly divided into control group and observation group by their admission order, and each group contained 60 cases. The control group received continuous cryotherapy by cryu-cuff pressurized cryotherapy automatic cycle system, and the observation group received additional air wave pressure treatment for combination treatment. Swelling and pain degree in joint of the two groups were observed. Results The observation group had lower indexes of joint pain degree and swelling in injured joint than the control group, and the difference had statistical significance (P<0.05). Conclusion The combination of continuous cryotherapy and air wave pressure treatment has good curative effect in relieving swelling and pain after total knee replacement. It can provide benefits for early rehabilitation exercise and knee joint recovery, and is worthy of clinical promotion.

  15. Skin perfusion pressure measured with a photo sensor in an air-filled plastic balloon: validity and reproducibility on the lower leg in normal subjects and patients suspected of obliterative arterial disease

    DEFF Research Database (Denmark)

    Nielsen, Steen Levin; Nielsen, Anne Lerberg; Vind, Susanne Haase

    2011-01-01

    An inflatable small plastic bag including a photo sensor was constructed for measurement of skin perfusion pressure avoiding the rim of the photo sensor over bony and tendineous surfaces of the tibia below the knee, at the ankle, and on the dorsal forefoot. Compression was obtained using a conical...

  16. Dielectric Barrier Discharge Air Plasma at Atmospheric Pressure Induced Oxidative Stress in Saccharomyces cerevisiae%大气压介质阻挡放电空气等离子体引起酿酒酵母氧化应激的研究

    Institute of Scientific and Technical Information of China (English)

    陈慧黠; 修志龙; 白凤武

    2013-01-01

    在产生等离子体的过程中会同时产生大量的自由基和准分子.作者研究了经大气压介质阻挡放电(dielectric barrier discharge,DBD)空气等离子体处理后酿酒酵母(Saccharomyce cerevisiae)细胞的氧化应激,发现酿酒酵母细胞在DBD空气等离子体处理后,胞内总抗氧化能力和谷胱甘肽还原酶活力都不同程度被激活,丙二醛含量也随处理时间的延长不断增加,胞内活性氧(reactive oxygen species,ROS)含量明显增加,细胞周期也出现严重的G1期阻滞,说明等离子体产生的大量自由基可引发酵母细胞的氧化应激.%Atmospheric pressure dielectric barrier discharge (DBD) air plasma is a source of reactive species,such as OH*,H*,O*,H2O2,O3,etc.The oxidative stress in Saccharomyces cerevisiae which was exposed to DBD air plasma at atmospheric pressure was studied.It was showed that the intracellular total antioxidant capability (T-AOC) and activity of glutathione reductase (GR) were activated,malondialdehyde (MDA) content increased in a treatment time-dependent manner,intracellular reactive oxygen species (ROS) content increased,and cell cycle arrested in G1 phase significantly.It was proved that oxidative stress was induced in S.cerevisiae when the cells were exposed to DBD air plasma.

  17. Air surveillance

    Energy Technology Data Exchange (ETDEWEB)

    Patton, G.W.

    1995-06-01

    This section of the 1994 Hanford Site Environmental Report summarizes the air surveillance and monitoring programs currently in operation at that Hanford Site. Atmospheric releases of pollutants from Hanford to the surrounding region are a potential source of human exposure. For that reason, both radioactive and nonradioactive materials in air are monitored at a number of locations. The influence of Hanford emissions on local radionuclide concentrations was evaluated by comparing concentrations measured at distant locations within the region to concentrations measured at the Site perimeter. This section discusses sample collection, analytical methods, and the results of the Hanford air surveillance program. A complete listing of all analytical results summarized in this section is reported separately by Bisping (1995).

  18. Air-Coupled Vibrometry

    Science.gov (United States)

    Döring, D.; Solodov, I.; Busse, G.

    Sound and ultrasound in air are the products of a multitude of different processes and thus can be favorable or undesirable phenomena. Development of experimental tools for non-invasive measurements and imaging of airborne sound fields is of importance for linear and nonlinear nondestructive material testing as well as noise control in industrial or civil engineering applications. One possible solution is based on acousto-optic interaction, like light diffraction imaging. The diffraction approach usually requires a sophisticated setup with fine optical alignment barely applicable in industrial environment. This paper focuses on the application of the robust experimental tool of scanning laser vibrometry, which utilizes commercial off-the-shelf equipment. The imaging technique of air-coupled vibrometry (ACV) is based on the modulation of the optical path length by the acoustic pressure of the sound wave. The theoretical considerations focus on the analysis of acousto-optical phase modulation. The sensitivity of the ACV in detecting vibration velocity was estimated as ~1 mm/s. The ACV applications to imaging of linear airborne fields are demonstrated for leaky wave propagation and measurements of ultrasonic air-coupled transducers. For higher-intensity ultrasound, the classical nonlinear effect of the second harmonic generation was measured in air. Another nonlinear application includes a direct observation of the nonlinear air-coupled emission (NACE) from the damaged areas in solid materials. The source of the NACE is shown to be strongly localized around the damage and proposed as a nonlinear "tag" to discern and image the defects.

  19. Technology Solutions Case Study: Air Leakage and Air Transfer Between Garage and Living Space, Waldorf, Maryland

    Energy Technology Data Exchange (ETDEWEB)

    None

    2014-11-01

    In this project, Building Science Corporation worked with production homebuilder K. Hovnanian to evaluate air transfer between the garage and living space in a single-family detached home constructed by a production homebuilder in compliance with the 2009 International Residential Code and the 2009 International Energy Conservation Code. The project gathered important information about the performance of whole-building ventilation systems and garage ventilation systems as they relate to minimizing flow of contaminated air from garage to living space. A series of 25 multipoint fan pressurization tests and additional zone pressure diagnostic testing measured the garage and house air leakage, the garage-to-house air leakage, and garage and house pressure relationships to each other and to outdoors using automated fan pressurization and pressure monitoring techniques. While the relative characteristics of this house may not represent the entire population of new construction configurations and air tightness levels (house and garage) throughout the country, the technical approach was conservative and should reasonably extend the usefulness of the results to a large spectrum of house configurations from this set of parametric tests in this one house. Based on the results of this testing, the two-step garage-to-house air leakage test protocol described above is recommended where whole-house exhaust ventilation is employed. For houses employing whole-house supply ventilation (positive pressure) or balanced ventilation (same pressure effect as the baseline condition), adherence to the EPA Indoor airPLUS house-to-garage air sealing requirements should be sufficient to expect little to no garage-to-house air transfer.

  20. 30 CFR 57.13011 - Air receiver tanks.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Air receiver tanks. 57.13011 Section 57.13011... Boilers § 57.13011 Air receiver tanks. Air receiver tanks shall be equipped with one or more automatic... exceeding the maximum allowable working pressure in a receiver tank by not more than 10 percent....

  1. Relating water and air flow characteristics in coarse granular materials

    DEFF Research Database (Denmark)

    Andreasen, Rune Røjgaard; Canga, Eriona; Poulsen, Tjalfe Gorm

    2013-01-01

    Water pressure drop as a function of velocity controls w 1 ater cleaning biofilter operation 2 cost. At present this relationship in biofilter materials must be determined experimentally as no 3 universal link between pressure drop, velocity and filter material properties have been established. 4...... Pressure drop - velocity in porous media is much simpler and faster to measure for air than for water. 5 For soils and similar materials, observations show a strong connection between pressure drop – 6 velocity relations for air and water, indicating that water pressure drop – velocity may be estimated 7...... from air flow data. The objective of this study was, therefore, to investigate if this approach is valid 8 also for coarse granular biofilter media which usually consists of much larger particles than soils. In 9 this paper the connection between the pressure drop – velocity relationships for air...

  2. SpaceX Dragon Air Circulation System

    Science.gov (United States)

    Hernandez, Brenda; Piatrovich, Siarhei; Prina, Mauro

    2011-01-01

    The Dragon capsule is a reusable vehicle being developed by Space Exploration Technologies (SpaceX) that will provide commercial cargo transportation to the International Space Station (ISS). Dragon is designed to be a habitable module while it is berthed to ISS. As such, the Dragon Environmental Control System (ECS) consists of pressure control and pressure equalization, air sampling, fire detection, illumination, and an air circulation system. The air circulation system prevents pockets of stagnant air in Dragon that can be hazardous to the ISS crew. In addition, through the inter-module duct, the air circulation system provides fresh air from ISS into Dragon. To utilize the maximum volume of Dragon for cargo packaging, the Dragon ECS air circulation system is designed around cargo rack optimization. At the same time, the air circulation system is designed to meet the National Aeronautics Space Administration (NASA) inter-module and intra-module ventilation requirements and acoustic requirements. A flight like configuration of the Dragon capsule including the air circulation system was recently assembled for testing to assess the design for inter-module and intra-module ventilation and acoustics. The testing included the Dragon capsule, and flight configuration in the pressure section with cargo racks, lockers, all of the air circulation components, and acoustic treatment. The air circulation test was also used to verify the Computational Fluid Dynamics (CFD) model of the Dragon capsule. The CFD model included the same Dragon internal geometry that was assembled for the test. This paper will describe the Dragon air circulation system design which has been verified by testing the system and with CFD analysis.

  3. Field mapping of ballistic pressure pulse sources

    Directory of Open Access Journals (Sweden)

    Rad Abtin Jamshidi

    2015-09-01

    Full Text Available Ballistic pressure pulse sources are used since late 1990s for the extracorporeal treatment of chronic Enthesitis. Newly indications are found in trigger-point-therapy for the treatment of musculoskeletal disorders. In both applications excellent results without relevant side effects were found in clinical trials. The technical principle of pressure pulse source is based on the same techniques used in air guns. A projectile is accelerated by pressurized air and hits the applicator with high kinetic energy. By this a compression wave travels through the material and induces a fast (4..5μs, almost singular pressure pulse of 2..10 MPa, which is followed by an equally short rarefaction phase of about the same amplitude. It is assumed that the pressure pulse accounts for the biomedical effects of the device. The slower inertial motion of the waveguide is damped by elastic stoppers, but still can be measured several micro seconds after the initial pressure pulse. In order to characterize the pressure pulse devices, field mapping is performed on several radial pressure pulse sources using the fiber optic hydrophone and a polyvinylidenfluorid (PVDF piezoelectric hydrophone. It could be shown that the current standard (IEC 61846 is not appropriate for characterization of ballistic pressure pulse sources.

  4. Air-water flow in subsurface systems

    Science.gov (United States)

    Hansen, A.; Mishra, P.

    2013-12-01

    Groundwater traces its roots to tackle challenges of safe and reliable drinking water and food production. When the groundwater level rises, air pressure in the unsaturated Vadose zone increases, forcing air to escape from the ground surface. Abnormally high and low subsurface air pressure can be generated when the groundwater system, rainfall, and sea level fluctuation are favorably combined [Jiao and Li, 2004]. Through this process, contamination in the form of volatile gases may diffuse from the ground surface into residential areas, or possibly move into groundwater from industrial waste sites. It is therefore crucial to understand the combined effects of air-water flow in groundwater system. Here we investigate theoretically and experimentally the effects of air and water flow in groundwater system.

  5. Thermal Conductivity of Humid Air

    Science.gov (United States)

    Beirão, S. G. S.; Ribeiro, A. P. C.; Lourenço, M. J. V.; Santos, F. J. V.; Nieto de Castro, C. A.

    2012-09-01

    In this article, measurements of the thermal conductivity of humid air as a function of pressure, temperature, and mole fraction of water, for pressures up to 5 MPa and temperatures up to 430 K, for different water contents (up to 10 % vapor mole fraction) are reported. Measurements were performed using a transient hot-wire apparatus capable of obtaining data with an uncertainty of 0.8 % for gases. However, as moist air becomes corrosive above 373 K and at pressures >5 MPa, the apparatus, namely, the pressure vessel and the cells had to be modified, by coating all stainless-steel parts with a titanium nitride thin film coating, about 4 μm thick, obtained by physical vapor deposition. The expanded uncertainty (coverage factor k = 2) of the present experimental thermal conductivity data is 1.7 %, while the uncertainty in the mole fraction is estimated to be better than 0.0006. Experimental details regarding the preparation of the samples, the precautions taken to avoid condensation in the tubes connected to the measuring cell, and the method developed for obtaining reliable values of the water content for the gas mixtures are discussed. A preliminary analysis of the application of the kinetic theory of transport properties in reacting mixtures to interpret the complex dependence of the thermal conductivity of humid air on water composition is addressed.

  6. Royal Danish Air Force. Air Operations Doctrine

    DEFF Research Database (Denmark)

    Nørby, Søren

    This brief examines the development of the first Danish Air Force Air Operations Doctrine, which was officially commissioned in October 1997 and remained in effect until 2010. The development of a Danish air power doctrine was heavily influenced by the work of Colonel John Warden (USAF), both...... through his book ”The Air Campaign” and his subsequent planning of the air campaign against Iraq in 1990-1991. Warden’s ideas came to Denmark and the Danish Air Force by way of Danish Air Force students attending the United States Air Force Air University in Alabama, USA. Back in Denmark, graduates from...... the Air University inspired a small number of passionate airmen, who then wrote the Danish Air Operations Doctrine. The process was supported by the Air Force Tactical Command, which found that the work dovetailed perfectly with the transformation process that the Danish Air Force was in the midst...

  7. Influence of the outlet air temperature on the thermohydraulic behaviour of air coolers

    Directory of Open Access Journals (Sweden)

    Đorđević Emila M.

    2003-01-01

    Full Text Available The determination of the optimal process conditions for the operation of air coolers demands a detailed analysis of their thermohydraulic behaviour on the one hand, and the estimation of the operating costs, on the other. One of the main parameters of the thermohydraulic behaviour of this type of equipment, is the outlet air temperature. The influence of the outlet air temperature on the performance of air coolers (heat transfer coefficient overall heat transfer coefficient, required surface area for heat transfer air-side pressure drop, fan power consumption and sound pressure level was investigated in this study. All the computations, using AirCooler software [1], were applied to cooling of the process fluid and the condensation of a multicomponent vapour mixture on two industrial devices of known geometries.

  8. Observation on the Efficacy of Air Pressure Instrument Combined with Surgical Debridement for the Treatment of Diabetic Foot Infection%气压治疗仪联合外科清创术治疗糖尿病足感染的疗效观察

    Institute of Scientific and Technical Information of China (English)

    莫建勋; 叶烨; 莫申荣; 唐盛发; 莫剑锋; 莫春荣; 熊红; 杨灵红

    2013-01-01

    [Objective] To explore the efficacy of air pressure instrument combined surgical debridement for the treatment of diabetic foot infection .[Methods] Totally 97 patients with diabetic foot infection were ran-domly divided into observation group( n=52) and control group( n=45) .All patients in two groups received routine blood sugar control ,anti-infection therapy and surgical debridement of wound weekly .The observation group was additionally treated with air pressure instrument at the same time .[Results] The foot ulcer healing rate of observation group was significantly higher than that of control group ( P<0 .05) ,and the regression of foot edema was obviously better than control group ( P <0 .05) .[Conclusion] Air pressure instrument com-bined with surgical debridement for the treatment of diabetic foot can alleviate limb edema and improve the healing rate of diabetic foot infection in patients with diabetes mellitus after debridement effectively .%[目的]探讨气压治疗仪联合外科清创术治疗糖尿病足感染的疗效。[方法]对97例糖尿病足感染患者随机分为观察组(52例)和对照组(45例),两组患者均常规控制血糖、抗感染、每周伤口进行外科清创等处理,观察组同时加用气压治疗仪联合治疗。[结果]观察组足溃疡愈合率显著高于对照组( P <0.05),且足部水肿消退明显优于对照组( P <0.05)。[结论]气压治疗仪联合外科清创术治疗糖尿病足感染能够减轻肢体水肿,有效提高糖尿病患者足部感染清创术后的愈合率。

  9. Normal Pressure Hydrocephalus (NPH)

    Science.gov (United States)

    ... local chapter Join our online community Normal Pressure Hydrocephalus (NPH) Normal pressure hydrocephalus is a brain disorder ... Symptoms Diagnosis Causes & risks Treatments About Normal Pressure Hydrocephalus Normal pressure hydrocephalus occurs when excess cerebrospinal fluid ...

  10. Hypertension (High Blood Pressure)

    Science.gov (United States)

    ... Surgery? A Week of Healthy Breakfasts Shyness Hypertension (High Blood Pressure) KidsHealth > For Teens > Hypertension (High Blood Pressure) Print ... rest temperature diet emotions posture medicines Why Is High Blood Pressure Bad? High blood pressure means a person's heart ...

  11. Low Blood Pressure

    Science.gov (United States)

    ... a problem. Sometimes blood pressure that is too low can also cause problems. Blood pressure is the ... reading is 90/60 or lower, you have low blood pressure. Some people have low blood pressure ...

  12. GSPEL - Air Filtration Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — Evaluation capabilities for air filtration devices The Air Filtration Lab provides testing of air filtration devices to demonstrate and validate new or legacy system...

  13. Pressurized waterproof case for electronic device

    KAUST Repository

    Berumen, Michael L.

    2013-01-31

    The pressurized waterproof case for an electronic device is particularly adapted for the waterproof containment and operation of a touch-screen computer or the like therein at some appreciable water depth. The case may be formed as an enclosure having an open top panel or face covered by a flexible, transparent membrane or the like for the operation of the touch-screen device within the case. A pressurizing system is provided for the case to pressurize the case and the electronic device therein to slightly greater than ambient in order to prevent the external water pressure from bearing against the transparent membrane and pressing it against the touch screen, thereby precluding operation of the touch screen device within the case. The pressurizing system may be a small gas cartridge (e.g., CO2), or may be provided from an external source, such as the diver\\'s breathing air. A pressure relief valve is also provided.

  14. Air-to-Air Missile Vector Scoring

    Science.gov (United States)

    2012-03-22

    64 4.6. Unscented Kalman Filter Performance in Air-to-Air Missile Scor - ing Application with Continuous Velocity Dynamics Model (Tar- get...Filter Performance in Air-to-Air Missile Scor - ing Application with Continuous Velocity Dynamics Model (Tar- get Aircraft Executing a Vertical Climb...Kalman Filter Performance in Air-to-Air Missile Scor - ing Application with Continuous Velocity Dynamics Model (Tar- get Aircraft Non-maneuvering

  15. 高气压空气环状感性耦合等离子体实验研究和参数诊断∗%Exp erimental investigation and parameter diagnosis of air high-pressure ring-shap ed inductively coupled plasma

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    The variable parameters like electron destiny (ne), electron collision frequency, covered-area and thickness have been regarded as the key factors for the electromagnetic scattering characteristics of the covering target. Therefore, an air inductively coupled plasma (ICP) generator of all-quartz chamber of 20 cm × 20 cm × 7 cm without magnetic confinement and grounded metal surface of substantial area is designed and conducted to study the discharge process and diagnose the parameters in this paper. The shape, E-H mode transition, and structure of inductively coupled plasma are observed, and the width and thickness change due to change of power and pressure are measured in experiments. Results show that the plasma is nearly uniformly full of the chamber in E-mode, while the shape of plasma rapidly changes to a ring in H-mode and the structure of inductively coupled plasma stratified into an electronegative core and an electropositive halo. It is observed clearly that the luminance of plasma increases slowly with the RF power in E-mode, but increases significantly in H-mode, which are proved through the relative spectral intensity variation of nitrogen 337.1 nm spectral lines due to the change of power and pressure. The width and thickness of the core region increase significantly with power, while decrease apparently with increasing pressure, which could be logically explained by the variation of RF magnetic induction amplitude distribution with power and by the theoretical diffusion analyses of electronegative gas. Since a mass of oxygen electronegative ion exists in the air inductively coupled plasma, the electron density (ne) diffusion models are different for the electronegative core and the electropositive halo. It is proved also by the theoretical drift-diffusion analyses that the electron density is distributed nearly uniformly in the electronegative core and decreased sharply in the electropositive halo. The model of electromagnetic wave propagation in

  16. 氧驱动雾化吸入与空气压缩泵雾化吸入治疗小儿哮喘的比较%Comparison of oxygen-driven atomizing inhalation and air pressure pump atomizing inhalation in the treatment of children with asthma

    Institute of Scientific and Technical Information of China (English)

    王正强

    2016-01-01

    目的:比较氧驱动雾化与空气压缩泵雾化吸入法治疗哮喘患儿的临床效果.方法:收治哮喘患儿112例,随机分为两组.治疗组采用氧驱动雾化吸入法,对照组采用空气压缩泵雾化吸入法,比较两组疗效.结果:治疗组总有效率96.43%,明显高于对照组的85.71%(P<0.05).结论:氧驱动雾化吸入法治疗哮喘患儿能大幅度缓解患者的病情.%Objective:To compare the clinical effect of oxygen-driven atomizing inhalation and air pressure pump atomizing inhalation in the treatment of children with asthma.Methods:112 cases of children with asthma were divided into two groups randomly.The treatment group was treated with oxygen-driven atomizing inhalation,the control group was treated with air pressure pump atomizing inhalation,and the curative effect of the two groups were compared.Results:The total effective rate of the treatment group 96.43% was significantly higher than that of the control group 85.71% (P<0.05).Conclusion:Oxygen-driven atomizing inhalation in the treatment of children with asthma could ease the patient''s condition greatly.

  17. Working Characteristics of Variable Intake Valve in Compressed Air Engine

    OpenAIRE

    Qihui Yu; Yan Shi; Maolin Cai

    2014-01-01

    A new camless compressed air engine is proposed, which can make the compressed air energy reasonably distributed. Through analysis of the camless compressed air engine, a mathematical model of the working processes was set up. Using the software MATLAB/Simulink for simulation, the pressure, temperature, and air mass of the cylinder were obtained. In order to verify the accuracy of the mathematical model, the experiments were conducted. Moreover, performance analysis was introduced to design c...

  18. R9 Air Districts

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Region 9 Air Districts layer is a compilation of polygons representing the California Air Pollution Control and Air Quality Management Districts, Arizona Air...

  19. AirData

    Data.gov (United States)

    U.S. Environmental Protection Agency — The AirData site provides access to yearly summaries of United States air pollution data, taken from EPA's air pollution databases. AirData has information about...

  20. California Air Basins

    Data.gov (United States)

    California Department of Resources — Air ResourcesCalifornia Air Resources BoardThe following datasets are from the California Air Resources Board: * arb_california_airbasins - California Air BasinsThe...

  1. Working Characteristics of Variable Intake Valve in Compressed Air Engine

    Directory of Open Access Journals (Sweden)

    Qihui Yu

    2014-01-01

    Full Text Available A new camless compressed air engine is proposed, which can make the compressed air energy reasonably distributed. Through analysis of the camless compressed air engine, a mathematical model of the working processes was set up. Using the software MATLAB/Simulink for simulation, the pressure, temperature, and air mass of the cylinder were obtained. In order to verify the accuracy of the mathematical model, the experiments were conducted. Moreover, performance analysis was introduced to design compressed air engine. Results show that, firstly, the simulation results have good consistency with the experimental results. Secondly, under different intake pressures, the highest output power is obtained when the crank speed reaches 500 rpm, which also provides the maximum output torque. Finally, higher energy utilization efficiency can be obtained at the lower speed, intake pressure, and valve duration angle. This research can refer to the design of the camless valve of compressed air engine.

  2. Working characteristics of variable intake valve in compressed air engine.

    Science.gov (United States)

    Yu, Qihui; Shi, Yan; Cai, Maolin

    2014-01-01

    A new camless compressed air engine is proposed, which can make the compressed air energy reasonably distributed. Through analysis of the camless compressed air engine, a mathematical model of the working processes was set up. Using the software MATLAB/Simulink for simulation, the pressure, temperature, and air mass of the cylinder were obtained. In order to verify the accuracy of the mathematical model, the experiments were conducted. Moreover, performance analysis was introduced to design compressed air engine. Results show that, firstly, the simulation results have good consistency with the experimental results. Secondly, under different intake pressures, the highest output power is obtained when the crank speed reaches 500 rpm, which also provides the maximum output torque. Finally, higher energy utilization efficiency can be obtained at the lower speed, intake pressure, and valve duration angle. This research can refer to the design of the camless valve of compressed air engine.

  3. Air Warfare

    Science.gov (United States)

    2002-03-01

    undoubtedly begat the shield; poisonous gases were countered by the mask. Surely men on the surface of the earth will not have to submit to violent air attack...properties, production methods and cost of helium are given in “Balloon and Airship Gases ,” a volume of the Ronald Aeronautic Library. 5 More complete...becomes and more inse - cure. We shall see later that even some of the men who were advancing in the path prescribed by the principle of mass

  4. Oscillation of large air bubble cloud

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Y.Y.; Kim, H.Y.; Park, J.K. [Korea Atomic Energy Research Inst., Daejeon (Korea, Republic of)

    2001-07-01

    The behavior of a large air bubble cloud, which is generated by the air discharged from a perforated sparger, is analyzed by solving Rayleigh-Plesset equation, energy equations and energy balance equation. The equations are solved by Runge-Kutta integration and MacCormack finite difference method. Initial conditions such as driving pressure, air volume, and void fraction strongly affect the bubble pressure amplitude and oscillation frequency. The pool temperature has a strong effect on the oscillation frequency and a negligible effect on the pressure amplitude. The polytropic constant during the compression and expansion processes of individual bubbles ranges from 1.0 to 1.4, which may be attributed to the fact that small bubbles oscillated in frequencies different from their resonance. The temperature of the bubble cloud rapidly approaches the ambient temperature, as is expected from the polytropic constants being between 1.0 and 1.4. (authors)

  5. The effects of air leaks on solar air heating systems

    Science.gov (United States)

    Elkin, R.; Cash, M.

    1979-01-01

    This paper presents the results of an investigation to determine the effects of leakages in collector and duct work on the system performance of a typical single-family residence solar air heating system. Positive (leakage out) and negative (leakage in) pressure systems were examined. Collector and duct leakage rates were varied from 10 to 30 percent of the system flow rate. Within the range of leakage rates investigated, solar contribution to heated space and domestic hot water loads was found to be reduced up to 30 percent from the no-leak system contribution with duct leakage equally divided between supply and return duct; with supply duct leakage greater than return leakage a reduction of up to 35 percent was noted. The negative pressure system exhibited a reduction in solar contribution somewhat larger than the positive pressure system for the same leakage rates.

  6. Effect of aeration on fast gas pressure tests

    Institute of Scientific and Technical Information of China (English)

    CHEN Yu-jia; JIANG Cheng-lin; LI Xiao-wei; TANG Jun; WANG Chen; YANG Fei-long; WANG Fa-kai; ZHANG Chao-jie; DENG Shu-hua

    2009-01-01

    Given the problem of the long time required for testing gas pressure, we propose a fast-test method in which we used a technique of fast borehole sealing and air replenishing. Based on the characteristics of gas emission from boreholes to be tested, we built a theoretical model for calculating parameters during the process of increasing natural pressure and aeration. Using this model, we investigated the effect of different aeration conditions on velocity of pressure tests. The result shows that: 1) aerating air into boreholes can speed up gas pressure tests and 2) the more similar the pressure of the aerated air to the original gas pressure, the smaller the gas volume absorbed by coal and the shorter the time needed in pressure test. A case study in the Lu'an mining area shows that the time needed for gas pressure test is only 4 h using our method of aeration and 29 h under conditions of increasing natural pressure, saving time by 86.2%. This case study also indicates that, by using the aeration method, only one hour is needed for gas pressure to reach a stable state, which breaks the record of the shortest time needed for gas pressure tests in China.

  7. Cryogenic Cooling System for Zero-Venting Storage of Supercritical Air Packs Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Supercritical air at cryogenic temperature is an attractive source of breathing air because of its very high density and low pressure. However, heat leak into the...

  8. A Study of the Fluid-Dynamic Pressure Fields on Compressor Reed Valves.

    Science.gov (United States)

    1985-12-01

    nigher *A pressures. The total pressure ol the reservoir wnicn suppiieo the air was measured on either a lovi-incn mercury manometer or a3 -v)-incn... mercury manometer . This was the same manometer which was used to measure the total pressure of the reservoir. A pressure tap ran from this total

  9. A Spectacular Experiment Exhibiting Atmospheric Pressure

    Science.gov (United States)

    Le Noxaïc, Armand

    2014-01-01

    The experiment described here is fairly easy to reproduce and dramatically shows the magnitude of ambient air pressure. Two circular plates of aluminum are applied one against the other. How do you make their separation very difficult? With only the help of an elastic band! You don't have to use a vacuum pump for this experiment.

  10. Selection of the air heat exchanger operating in a gas turbine air bottoming cycle

    Science.gov (United States)

    Chmielniak, Tadeusz; Czaja, Daniel; Lepszy, Sebastian

    2013-12-01

    A gas turbine air bottoming cycle consists of a gas turbine unit and the air turbine part. The air part includes a compressor, air expander and air heat exchanger. The air heat exchanger couples the gas turbine to the air cycle. Due to the low specific heat of air and of the gas turbine exhaust gases, the air heat exchanger features a considerable size. The bigger the air heat exchanger, the higher its effectiveness, which results in the improvement of the efficiency of the gas turbine air bottoming cycle. On the other hand, a device with large dimensions weighs more, which may limit its use in specific locations, such as oil platforms. The thermodynamic calculations of the air heat exchanger and a preliminary selection of the device are presented. The installation used in the calculation process is a plate heat exchanger, which is characterized by a smaller size and lower values of the pressure drop compared to the shell and tube heat exchanger. Structurally, this type of the heat exchanger is quite similar to the gas turbine regenerator. The method on which the calculation procedure may be based for real installations is also presented, which have to satisfy the economic criteria of financial profitability and cost-effectiveness apart from the thermodynamic criteria.

  11. Blast Quantification Using Hopkinson Pressure Bars.

    Science.gov (United States)

    Clarke, Samuel D; Fay, Stephen D; Rigby, Samuel E; Tyas, Andrew; Warren, James A; Reay, Jonathan J; Fuller, Benjamin J; Gant, Matthew T A; Elgy, Ian D

    2016-07-05

    Near-field blast load measurement presents an issue to many sensor types as they must endure very aggressive environments and be able to measure pressures up to many hundreds of megapascals. In this respect the simplicity of the Hopkinson pressure bar has a major advantage in that while the measurement end of the Hopkinson bar can endure and be exposed to harsh conditions, the strain gauge mounted to the bar can be affixed some distance away. This allows protective housings to be utilized which protect the strain gauge but do not interfere with the measurement acquisition. The use of an array of pressure bars allows the pressure-time histories at discrete known points to be measured. This article also describes the interpolation routine used to derive pressure-time histories at un-instrumented locations on the plane of interest. Currently the technique has been used to measure loading from high explosives in free air and buried shallowly in various soils.

  12. 针-板DBD微流注与微辉光交替生成的机理研究%Atmospheric pressure streamer and glow-discharge generated alternately by pin-to-plane dielectric barrier discharge in air

    Institute of Scientific and Technical Information of China (English)

    俞哲; 张芝涛; 于清旋; 许少杰; 姚京; 白敏冬; 田一平; 刘开颖

    2012-01-01

    Performance of producing a high energy electron can be improved, if the glow discharge is generated in a system of dielectric barrier discharge. In this paper, different discharge modes of pin-to-plane dielectric barrier discharge are investigated in atmospheric pressure. Different discharge modes are observed in the positive half-period and negative half-period of the discharge. When and applied voltage is 3 kV, a streamer mode appear in the positive half-period and a corona (or Trichel discharge) mode occurs in negative half-period. When the applied voltage is 6 kV, a streamer emerges in the positive half-period and a micro glow discharge is present in the negative half-period. The micro glow discharge has hierarchical structure like that typical low pressure glow discharge produces. The generation of micro glow discharge is due to, enough strong cathode electric field strength and effective secondary electron emission process around naked negative electrode. The glow discharge transforming to arc discharge is avoided due to dielectric layer.%在介质阻挡放电体系中产生辉光放电可以有效的提高放电体系产生高能电子的性能,为等离子体化学反应提供更加丰富的活性粒子.本文对针一板介质阻挡放电体系下的放电模式进行了研究,实验发现放电正负半周期表现出不同的放电模式,激励电压为3kV时放电正负半周期分别为微流注放电和电晕放电(或者Trichel脉冲放电),激励电压为6kV时放电正负半周期分别为微流注放电和微辉光放电.微辉光放电形貌具有与典型辉光放电相同的分层次放电结构,分析了激励电压6kV时的放电过程,认为足够强的阴极电场强度和裸露针状电极形成的有效的二次电子发射过程是形成微辉光放电的主要因素,绝缘介质层的存在避免了微辉光放电向弧光放电过渡.

  13. Preventing pressure ulcers

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/patientinstructions/000147.htm Preventing pressure ulcers To use the sharing features on this page, please enable JavaScript. Pressure ulcers are also called bedsores, or pressure sores. They ...

  14. High Blood Pressure

    Science.gov (United States)

    ... normal blood pressure 140/90 or higher is high blood pressure Between 120 and 139 for the top number, ... prehypertension. Prehypertension means you may end up with high blood pressure, unless you take steps to prevent it. High ...

  15. High Blood Pressure (Hypertension)

    Science.gov (United States)

    ... Print Page Text Size: A A A Listen High Blood Pressure (Hypertension) Nearly 1 in 3 American adults has ... weight. How Will I Know if I Have High Blood Pressure? High blood pressure is a silent problem — you ...

  16. Blood Pressure Test

    Science.gov (United States)

    ... an online personal health record or blood pressure tracker, for example. This gives you the option of ... lower your blood pressure. Exercise regularly. Regular physical activity can help lower your blood pressure and keep ...

  17. Low Blood Pressure (Hypotension)

    Science.gov (United States)

    ... and rises sharply on waking. Blood pressure: How low can you go? What's considered low blood pressure ... even life-threatening disorders. Conditions that can cause low blood pressure Some medical conditions can cause low ...

  18. Low-Pressure Generator Makes Cleanrooms Cleaner

    Science.gov (United States)

    2005-01-01

    Scientists at NASA's Kennedy Space Center work in cleanrooms: laboratories with high degrees of cleanliness provided by strict control of particles such as dust, lint, or human skin. They are contaminant-free facilities, where the air is repeatedly filtered, and surfaces are smooth to prevent particles from getting lodged. Technicians working in these environments wear specially designed cleanroom "bunny suits" and booties over their street clothes, as well as gloves and face masks to avoid any contamination that may be imparted from the outside world. Even normal paper is not allowed in cleanrooms, only cleanroom low-particulate paper. These are sensitive environments where precision work, like the production of silicon chips or hard disk drives, is performed. Often in cleanrooms, positive air pressure is used to force particles outside of the isolated area. The air pressure in the Kennedy cleanrooms is monitored using high-accuracy, low-differential pressure transducers that require periodic calibration. Calibration of the transducers is a tricky business. In prior years, the analysis was performed by sending the transducers to the Kennedy Standards Laboratory, where a very expensive cross-floated, labor- intensive, dead-weight test was conducted. In the early 1990s, scientists at Kennedy determined to develop a technique and find equipment to perform qualification testing on new low-differential pressure transducers in an accurate, cost-effective manner onsite, without requiring an environmentally controlled room. They decided to use the highly accurate, cost-effective Setra Model C264 as the test transducer. For qualification testing of the Setra, though, a portable, lower-cost calibrator was needed that could control the differential pressure to a high degree of resolution and transfer the accuracy of the Standards Laboratory testing to the qualification testing. The researchers decided that, to generate the low-differential pressure setpoints needed for

  19. Transpulmonary passage of venous air emboli

    Science.gov (United States)

    Butler, B. D.; Hills, B. A.

    1985-01-01

    Twenty-seven paralyzed anesthetized dogs were embolized with venous air to determine the effectiveness of the pulmonary vasculature for bubble filtration or trapping. Air doses ranged from 0.05 to 0.40 ml/kg min in 0.05-ml increments with ultrasonic Doppler monitors placed over arterial vessels to detect any microbubbles that crossed the lungs. Pulmonary vascular filtration of the venous air infusions was complete for the lower air doses ranging from 0.05 to 0.30 ml/kg min. When the air doses were increased to 0.35 ml/kg min, the filtration threshold was exceeded with arterial spillover of bubbles occurring in 50 percent of the animals and reaching 71 percent for 0.40 ml/kg min. Significant elevations were observed in pulmonary arterial pressure and pulmonary vascular resistance. Systemic blood pressure and cardiac output decreased, whereas left ventricular end-diastolic pressure remained unchanged. The results indicate that the filtration of venous bubbles by the pulmonary vasculature was complete when the air infusion rates were kept below a threshold value of 0.30 ml/kg min.

  20. Imaging based optofluidic air flow meter with polymer interferometers defined by soft lithography.

    Science.gov (United States)

    Song, Wuzhou; Psaltis, Demetri

    2010-08-01

    We present an optofluidic chip with integrated polymer interferometers for measuring both the microfluidic air pressure and flow rate. The chip contains a microfluidic circuit and optical cavities on a polymer which was defined by soft lithography. The pressure can be read out by imaging the interference patterns of the cavities. The air flow rate was then calculated from the differential pressure across a microfluidic Venturi circuit. Air flow rate measurement in the range of 0-2mg/second was demonstrated. This device provides a simple and versatile way for in situ measuring the microscale air pressure and flow on chip.

  1. Seed disinfection effect of atmospheric pressure plasma and low pressure plasma on Rhizoctonia solani.

    Science.gov (United States)

    Nishioka, Terumi; Takai, Yuichiro; Kawaradani, Mitsuo; Okada, Kiyotsugu; Tanimoto, Hideo; Misawa, Tatsuya; Kusakari, Shinichi

    2014-01-01

    Gas plasma generated and applied under two different systems, atmospheric pressure plasma and low pressure plasma, was used to investigate the inactivation efficacy on the seedborne pathogenic fungus, Rhizoctonia solani, which had been artificially introduced to brassicaceous seeds. Treatment with atmospheric plasma for 10 min markedly reduced the R. solani survival rate from 100% to 3% but delayed seed germination. The low pressure plasma treatment reduced the fungal survival rate from 83% to 1.7% after 10 min and the inactivation effect was dependent on the treatment time. The seed germination rate after treatment with the low pressure plasma was not significantly different from that of untreated seeds. The air temperature around the seeds in the low pressure system was lower than that of the atmospheric system. These results suggested that gas plasma treatment under low pressure could be effective in disinfecting the seeds without damaging them.

  2. Air filtration and indoor air quality

    DEFF Research Database (Denmark)

    Bekö, Gabriel

    2006-01-01

    decent ventilation and air cleaning/air filtration, high indoor air quality cannot be accomplished. The need for effective air filtration has increased with increasing evidence on the hazardous effects of fine particles. Moreover, the air contains gaseous pollutants, removal of which requires various air....... These contradictions should motivate manufacturers and researchers to develop new efficient filtration techniques and/or improve the existing ones. Development of low polluting filtration techniques, which are at the same time easy and inexpensive to maintain is the way forward in the future....

  3. Air wave pressure therapy in prevention of deep vein thrombosis of the lower extremity after total knee arthroplasty%空气波压力治疗预防全膝关节置换后下肢深静脉血栓

    Institute of Scientific and Technical Information of China (English)

    唐进; 杨涛; 熊小江; 陈林; 程智勇; 占方彪; 廖乙名

    2013-01-01

    背景:大量文献研究表明,空气波压力治疗在预防髋部大手术后下肢深静脉血栓形成中有重要作用。  目的:探讨空气波压力治疗仪对预防全膝关节置换后下肢深静脉血栓的效果。  方法:80例全膝关节置换患者随机数字表法均分为试验组和对照组,对照组行常规治疗与护理加个人行为功能锻炼,试验组在对照组基础上,置换后第2天采用空气波压力治疗仪治疗双下肢;比较两组患者患肢肿胀指数、凝血综合指数及发生下肢深静脉血栓的例数。  结果与结论:治疗后2周,试验组肿胀指数、凝血综合指数及发生下肢深静脉血栓的例数明显减少,其效果明显优于对照组,差异有显著性意义(P OBJECTIVE:To explore the efficacy of air wave pressure therapy on deep vein thrombosis of the lower extremity in patients with total knee arthroplasty. METHODS:A total of 80 patients with total knee arthroplasty were randomly divided into experimental group and control group. Patients in the control group were treated only with conventional method to help the patient massage the lower extremity by the nurse and combined with active functional exercise;patients in the experimental group were treated with air wave pressure therapy at 2 days postoperatively, and were also treated with conventional method to help the patient massage the lower extremity by the nurse and combined with active functional exercise. Swel ing index, coagulation index and the number of patients with deep venous thrombosis of the lower extremity were recorded in both groups. RESULTS AND CONCLUSION:At 2 weeks after treatment, swel ing index, coagulation index and the number of patients with deep venous thrombosis of the lower extremity were significantly reduced in the experimental group, and its effects were significantly better than those in the control group (P<0.05). Early use of air wave pressure therapy after total

  4. 40 CFR 1065.315 - Pressure, temperature, and dewpoint calibration.

    Science.gov (United States)

    2010-07-01

    ...) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calibrations and Verifications Measurement of Engine...) Pressure. We recommend temperature-compensated, digital-pneumatic, or deadweight pressure calibrators, with... quantities that are NIST-traceable within 0.5% uncertainty. (2) Temperature. We recommend digital...

  5. Reducing cyclone pressure drop with evasés

    Science.gov (United States)

    Cyclones are widely used to separate particles from gas flows and as air emissions control devices. Their cost of operation is proportional to the fan energy required to overcome their pressure drop. Evasés or exit diffusers potentially could reduce exit pressure losses without affecting collection...

  6. Air Safety Spinoffs

    Science.gov (United States)

    1977-01-01

    Weight saving-even a matter of a few pounds-is an important consideration in airplane design and . construction. Boeing saved 200 pounds simply by substituting a new type of compressed gas cylinder on their 747 commercial airliners. For quickly evacuating passengers in the event of a ground emergency the 747 escape chutes allow ' passengers to slide to safety from the two-story height of the cabin deck. The chutes pop out of exitways and are automatically inflated in seconds by compressed air stored in pressure vessels. Boeing's weight saving resulted from a recent changeover to a new type of pressure vessel built by Structural Composites Industries Inc. of Azusa, Cal. The company employs technology originally developed for rocket motor casings; the cylinders are constructed by winding fibers around an aluminum liner. This technique offers high strength for very low weight-in this case 60 percent less than the pressure vessels earlier used on the 747. Another contribution to improved air safety is an underwater locator device. Called the "Pinger," it uses sonar techniques to locate aircraft crashed in water-or, more specifically, to recover the flight recorder aboard the airplane. Its recovery provides clues as to what caused the accident and suggests measures to prevent similar future occurrences. Until recently, there was no way to recover flight recorders aboard aircraft lost in water crashes. The Pinger, now serving 95 percent of the airline industry, provides an answer. Key element of the Pinger system is a small, battery-powered transmitter, or homing beacon, included as part of the recorder package. For as long as 30 days, the transmitter sends out an acoustic signal from water depths up to 20,000 feet. The other element of the system is a receiver, used by search crews to home in on the transmitter's signal. Originating as a U.S. Navy project, this device was refined and further developed by NASA's Langley Research Center to retrieve submerged nose cones

  7. Air leakage in residential solar heating systems

    Science.gov (United States)

    Shingleton, J. G.; Cassel, D. E.; Overton, R. L.

    1981-02-01

    A series of computer simulations was performed to evaluate the effects of component air leakage on system thermal performance for a typical residential solar heating system, located in Madison, Wisconsin. Auxiliary energy required to supplement solar energy for space heating was determined using the TRNSYS computer program, for a range of air leakage rates at the solar collector and pebble bed storage unit. The effects of heat transfer and mass transfer between the solar equipment room and the heated building were investigated. The effect of reduced air infiltration into the building due to pressurized by the solar air heating system were determined. A simple method of estimating the effect of collector array air leakage on system thermal performance was evaluated, using the f CHART method.

  8. Correction of static pressure on a research aircraft in accelerated flight using differential pressure measurements

    Directory of Open Access Journals (Sweden)

    A. R. Rodi

    2012-05-01

    Full Text Available Geometric altitude data from a combined Global Navigation Satellite System (GNSS and inertial measurement unit (IMU system on the University of Wyoming King Air research aircraft are used to estimate acceleration effects on static pressure measurement. Using data collected during periods of accelerated flight, comparison of measured pressure with that derived from GNSS/IMU geometric altitude show that errors exceeding 150 Pa can occur which is significant in airspeed and atmospheric air motion determination. A method is developed to predict static pressure errors from analysis of differential pressure measurements from a Rosemount model 858 differential pressure air velocity probe. The method was evaluated with a carefully designed probe towed on connecting tubing behind the aircraft – a "trailing cone" – in steady flight, and shown to have a precision of about ±10 Pa over a wide range of conditions including various altitudes, power settings, and gear and flap extensions. Under accelerated flight conditions, compared to the GNSS/IMU data, this algorithm predicts corrections to a precision of better than ±20 Pa. Some limiting factors affecting the precision of static pressure measurement on a research aircraft are examined.

  9. Study on Wood Drying Properties under Vacuum-floating Pressure

    Institute of Scientific and Technical Information of China (English)

    ZHANGBiguang; YISonghn; CHANGJianmin; LIXianjun

    2004-01-01

    Using Masson pine as specimens, when drying mediums are overheated steam and hot-air respectively, preheating characteristics of wood under vacuum-floating pressure drying are discussed by measurement of internal temperature field and variation of moisture content during period of preheating. The relationship between drying medium conditions and drying rate of wood reveals that, firstly, compared with process of air-drying, time needed to be preheated under vacuum-floating decreased dramatically, meanwhile,the magnitude of condensation on the surface is relatively larger. Secondly, drying rate of wood under vacuum-floating pressure increases coupled with temperature of medium, reduction of absolute pressure,and raise of fluctuation rate of pressure. The sequence of factors contribution to drying rate is listed as following: temperature of medium (t) > fluctuation rate of pressure (f)> absolute pressure (p).

  10. Acute management of vascular air embolism

    Directory of Open Access Journals (Sweden)

    Shaikh Nissar

    2009-01-01

    Full Text Available Vascular air embolism (VAE is known since early nineteenth century. It is the entrainment of air or gas from operative field or other communications into the venous or arterial vasculature. Exact incidence of VAE is difficult to estimate. High risk surgeries for VAE are sitting position and posterior fossa neurosurgeries, cesarean section, laparoscopic, orthopedic, surgeries invasive procedures, pulmonary overpressure syndrome, and decompression syndrome. Risk factors for VAE are operative site 5 cm  above the heart, creation of pressure gradient which will facilitate entry of air into the circulation, orogenital sex during pregnancy, rapid ascent in scuba (self contained underwater breathing apparatus divers and barotrauma or chest trauma. Large bolus of air can lead to right ventricular air lock and immediate fatality. In up to 35% patient, the foramen ovale is patent which can cause paradoxical arterial air embolism. VAE affects cardiovascular, pulmonary and central nervous system. High index of clinical suspicion is must to diagnose VAE. The transesophgeal echocardiography is the most sensitive device which will detect smallest amount of air in the circulation. Treatment of VAE is to prevent further entrainment of air, reduce the volume of air entrained and haemodynamic support. Mortality of VAE ranges from 48 to 80%. VAE can be prevented significantly by proper positioning during surgery, optimal hydration, avoiding use of nitrous oxide, meticulous care during insertion, removal of central venous catheter, proper guidance, and training of scuba divers.

  11. Air pollution

    Energy Technology Data Exchange (ETDEWEB)

    1974-12-01

    Air pollution conditions in Iwakuni city were monitored at 9 monitoring stations, and 21 locations where sulfur oxides were measured by the lead peroxide candle method, and 13 locations where particulates concentrations were determined by the deposit cage method. The average SO/sub x/ concentrations in 1973 measured by the lead peroxide candle method ranged from 0.17 mg sulfur trioxide/day/100 sq cm at the Miso Office to 0.58 mg SO/sub 3//day/100 sq cm at Mitsui Sekiyu Shataku. The average SO/sub x/ concentrations measured by the conductivity method ranged from 0.021 ppM at Kazuki Kominkan to 0.037 ppM at the Higashi Fire Department. Only 58% of a total of 264 measurement days gave hourly average concentrations below the environmental standard of 0.04 ppM at the Higashi Fire Deparment. The average airborne particulate concentrations ranged from 0.050 mg/cu m at Totsu Kominkan to 0.056 mg/cu at the Higashi Fire Department. The average nitrogen oxides concentrations measured by the Saltzman method ranged from 0.007 ppM to 0.061 ppM. The average oxidant concentrations at the Iwakuni Municipal Office and Kazuki Kominkan were 0.028 ppM and 0.037 ppM, respectively.

  12. Air flotation treatment of salmon processing waste water

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This paper discusses methods for the reduction of the pollution strength of salmon processing waste water. Past research has indicated the success of air pressure...

  13. The effect of a photocatalytic air purifier on indoor air quality quantified using different measuring methods

    DEFF Research Database (Denmark)

    Kolarik, Barbara; Wargocki, Pawel; Skorek-Osikowska, A.;

    2010-01-01

    The effect on indoor air quality of an air purifier based on photocatalytic oxidation (PCO) was determined by different measuring techniques: sensory assessments of air quality made by human subjects, Proton-Transfer-Reaction Mass Spectrometry (PTR-MS) and chromatographic methods (Gas...... Chromatography/Mass Spectrometry and High-Pressure Liquid Chromatography with UV detection). The experiment was conducted in a simulated office, ventilated with 0.6 h(-1), 2.5 h(-1) and 6 h(-1), in the presence of additional pollution sources (carpet, chipboard and linoleum). At the lowest air change rate......, additional measurements were made with no pollution sources present in the office. All conditions were tested with the photocatalytic air purifier turned on and off. The results show that operation of the air purifier in the presence of pollutants emitted by building materials and furniture improves indoor...

  14. 大气压直流正电晕放电暂态空间电荷分布仿真研究%Numerical simulation of transient space charge distribution of DC positive corona discharge under atmospheric pressure air

    Institute of Scientific and Technical Information of China (English)

    廖瑞金; 伍飞飞; 刘兴华; 杨帆; 杨丽君; 周之; 翟蕾

    2012-01-01

    本文提出了流体一化学动理学二维正电晕放电混合模型,该模型包含12种粒子间的27种化学反应,并且考虑光电离的影响.此外,在实验室内对该模型开展试验验证,单次脉冲波形及伏安特性曲线符合较好.基于上述模型,本文研究了在外施电压3kV时棒一板电极正电晕放电过程中的电场分布、电子温度分布、空间电荷分布的发展规律,并对电晕放电过程中粒子的成分进行了详细分析,讨论了电子、正负离子、中性粒子在放电过程中的生成规律及对电晕放电的影响.结果表明:在整个电晕放电过程中,电子温度分布和电场强度分布曲线相似,电子密度维持在10^19m-3左右,只发现带正电的等离子体特征.O4+密度是放电过程中数量最多的正离子,O2+和N2+在二次电子发射过程中具有重要作用,O2-离子和O分别是负离子和中性粒子中数量最多的粒子,由于负离子和中性粒子在电晕放电过程中数量较小,因而起的作用相对较小.%Corona discharges are usually generated at sharp points, edges or on thin wires where the electric field is strongly concentrated. With the rapid development of extra and ultra high-voltage transmission lines, the air corona discharge becomes one of the critical problems associated with high-voltage lines, which can lead to the deterioration of insulation systems, power loss, radio noise. Corona discharge studies have been undertaken for many years, not only because of the scientific interest in the corona mechanism but also because of its practical engineering importance. Transient space charge distribution effect that is one of the important canses in the process of corona discharge, is closely related to the corona discharge mechanism and onset, self-sustaining. In this paper, we present an improved self-consistent, multi-component and two-dimensional plasma hybrid model for simulating the

  15. High pressure technology 1994

    Energy Technology Data Exchange (ETDEWEB)

    Kapp, J.A.; Picqueuer, L.M. (eds.)

    1994-01-01

    This volume is divided into four sessions: fracture mechanics applications to high pressure vessels; high pressure code issues; high pressure design, analysis, and safety concerns; and military and other high pressure applications. Separate abstracts were prepared for eleven papers of this conference.

  16. Hypertension (High Blood Pressure)

    Science.gov (United States)

    ... Loss Surgery? A Week of Healthy Breakfasts Shyness Hypertension (High Blood Pressure) KidsHealth > For Teens > Hypertension (High Blood Pressure) A ... rest temperature diet emotions posture medicines Why Is High Blood Pressure Bad? High blood pressure means a person's heart ...

  17. Air Sensor Toolbox

    Science.gov (United States)

    Air Sensor Toolbox provides information to citizen scientists, researchers and developers interested in learning more about new lower-cost compact air sensor technologies and tools for measuring air quality.

  18. HEPA air filter (image)

    Science.gov (United States)

    ... pet dander and other irritating allergens from the air. Along with other methods to reduce allergens, such ... controlling the amount of allergens circulating in the air. HEPA filters can be found in most air ...

  19. GSPEL - Air Filtration Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — Evaluation capabilities for air filtration devicesThe Air Filtration Lab provides testing of air filtration devices to demonstrate and validate new or legacy system...

  20. Lead (Pb) Air Pollution

    Science.gov (United States)

    ... States Environmental Protection Agency Search Search Lead (Pb) Air Pollution Share Facebook Twitter Google+ Pinterest Contact Us As ... and protect aquatic and terrestrial ecosystems. Lead (Pb) Air Pollution Lead Air Pollution Basics How does lead get ...