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Sample records for partial liquid ventilation

  1. Liquid ventilation

    PubMed Central

    Sarkar, Suman; Paswan, Anil; Prakas, S.

    2014-01-01

    Human have lungs to breathe air and they have no gills to breath liquids like fish. When the surface tension at the air-liquid interface of the lung increases as in acute lung injury, scientists started to think about filling the lung with fluid instead of air to reduce the surface tension and facilitate ventilation. Liquid ventilation (LV) is a technique of mechanical ventilation in which the lungs are insufflated with an oxygenated perfluorochemical liquid rather than an oxygen-containing gas mixture. The use of perfluorochemicals, rather than nitrogen as the inert carrier of oxygen and carbon dioxide offers a number of advantages for the treatment of acute lung injury. In addition, there are non-respiratory applications with expanding potential including pulmonary drug delivery and radiographic imaging. It is well-known that respiratory diseases are one of the most common causes of morbidity and mortality in intensive care unit. During the past few years several new modalities of treatment have been introduced. One of them and probably the most fascinating, is of LV. Partial LV, on which much of the existing research has concentrated, requires partial filling of lungs with perfluorocarbons (PFC's) and ventilation with gas tidal volumes using conventional mechanical ventilators. Various physico-chemical properties of PFC's make them the ideal media. It results in a dramatic improvement in lung compliance and oxygenation and decline in mean airway pressure and oxygen requirements. No long-term side-effect reported. PMID:25886321

  2. The use of intratracheal pulmonary ventilation and partial liquid ventilation in newborn piglets with meconium aspiration syndrome.

    PubMed

    Onasanya, Babatunde I.; Rais-Bahrami, Khodayar; Rivera, Oswaldo; Seale, Winslow R.; Short, Billie L.

    2001-01-01

    OBJECTIVE: To determine whether intratracheal pulmonary ventilation (ITPV) combined with partial liquid ventilation (PLV) improves oxygenation and ventilation at lower mean airway and peak inspiratory pressures when compared with conventional mechanical ventilation in a piglet model of meconium aspiration syndrome. DESIGN: Prospective, randomized, interventional study. SETTING: Animal Research Laboratory at the Children's National Medical Center, Washington, DC. SUBJECTS: Twenty newborn piglets, 1 to 2 wks of age, 1.8-2.8 kg in weight. INTERVENTION: The animals were anesthetized, paralyzed, and intubated with a 4.0 mm (internal diameter) endotracheal tube via a tracheostomy and were ventilated. Catheters were placed in the femoral artery and vein. Seven milliliters per kilogram of 20% human meconium was insufflated into the lungs over 30 mins. Dynamic pulmonary compliance was measured before and after instillation of meconium. Animals were ventilated to maintain arterial blood gases in a normal range, that is, pH = 7.35-7.45, Paco(2) = 40-45 torr (5.3-6.0 kPa), and Pao(2) = 70-90 torr (9.3-12.0 kPa). Ventilator settings were increased as needed to a maximum setting of Fio(2) = 1.0, peak inspiratory pressure (PIP) = 40 cm H(2)O, positive end-expiratory pressure = 5 cm H(2)O, and intermittent mandatory ventilation = 60 bpm. After a period of stabilization, 30 mL/kg of perflubron (Liquivent; Alliance Pharmaceutical Corp., San Diego, CA) was given intratracheally over 30 mins and the animals were randomized to either ITPV or control group. Measurements and RESULTS: Arterial blood gases were taken every 30 mins, and ventilatory settings were adjusted to achieve the targeted blood gas parameters. The animals' temperature, arterial blood pressure, heart rate, and oxygen saturation were monitored continuously. There was a significant decrease in the dynamic pulmonary compliance measurements in both groups immediately after meconium instillation. Compliance measurements

  3. Effect of partial liquid ventilation and nebulized perfluorocarbon on CT lung density distribution: randomized controlled study of experimental lung injury.

    PubMed

    Kelly, K P; Stenson, B J; Drummond, G B

    2005-05-01

    Perfluorocarbon (PFC) liquid can improve gas exchange in acute lung injury. How PFC aerosol is distributed in the lung is unknown. We induced lung injury in rabbits with saline lavage, followed by mechanical ventilation in the supine position. The animals were divided into three groups: a control group, a group treated with partial liquid ventilation and a group given nebulized perfluorocarbon (PF 5080). We made CT image slices of the excised lungs. In the apical, middle and caudal slices we defined three regions of interest, from anterior to posterior, and noted the mean attenuation of each area. We also studied two rabbits which had not received lung injury or mechanical ventilation. Group means were different between the normal rabbits and all three study groups. There was a difference between the control and partial liquid ventilation groups, and between the partial liquid ventilation and nebulized groups, but no difference between the nebulized and control groups. Within each treatment group, there was no regional difference in the distribution of density. PF 5080 is not deposited in large amounts by aerosol. Less PFC was found in the lungs after partial liquid ventilation than expected. Within treatment groups, lung densities indicate less gravitational and regional differences than found in other studies.

  4. Partial liquid ventilation shows dose-dependent increase in oxygenation with PEEP and decreases lung injury associated with mechanical ventilation.

    PubMed

    Suh, G Y; Chung, M P; Park, S J; Koh, Y; Kang, K W; Kim, H; Han, J; Rhee, C H; Kwon, O J

    2000-09-01

    The purpose of this article is to evaluate the effect of positive end-expiratory pressure (PEEP) during partial liquid ventilation (PLV) and to investigate if lung damage associated with mechanical ventilation can be reduced by PLV. Twenty-two New-Zealand white rabbits were ventilated in pressure-controlled mode maintaining constant tidal volume (10 mL/kg). Lung injury was induced by repeated saline lavage (PaO2 < 100 mm Hg). Two incremental PEEP steps maneuvers (IPSMs) from 2 to 10 cm H2O in 2 cm H2O steps were performed sequentially. The control group received the first IPSM in the supine position and were turned prone for the second IPSM. In the PLV group (n = 7), 12 mL/kg of perfluorodecalin was instilled after lung injury before the two IPSMs. The early prone group (n = 7) received both IPSMs in the prone position. Parameters of gas exchange, lung mechanics, and hemodynamics as well as pathology were examined. During the first IPSM, the PLV group showed a significant increase in PaO2 after instillation of perfluorodecalin (P < .05) and then showed a dose-dependent increase in PaO2 with PEER. The control and EP groups showed improvement in PaO2 only at higher PEEP, eventually showing no intergroup differences at PEEP of 10 cm H2O. During the second IPSM only the PLV group retained its ability to increase PaO2 to the level obtained during the first IPSM (P < .05 compared with control and EP groups). During the first IPSM all three groups showed increasing trend in static compliance (Cst) with PEEP peaking at PEEP of 8 cm H2O. During the second IPSM, only the PLV group showed increase in static compliance with PEEP (P < .05 compared with other groups). Lung histology revealed significantly less hyaline membrane formation in the PLV group (P < .05). PLV shows dose-dependent increase in oxygenation with PEEP and may reduce lung damage associated with mechanical ventilation.

  5. A comparison of conventional surfactant treatment and partial liquid ventilation on the lung volume of injured ventilated small lungs.

    PubMed

    Proquitté, Hans; Hartenstein, Sebastian; Koelsch, Uwe; Wauer, Roland R; Rüdiger, Mario; Schmalisch, Gerd

    2013-08-01

    As an alternative to surfactant therapy (ST), partial liquid ventilation (PLV) with perfluorocarbons (PFC) has been considered as a treatment for acute lung injury (ALI) in newborns. The instilled PFC is much heavier than the instilled surfactant and the aim of this study was to investigate whether PLV, compared to ST, increases the end-expiratory volume of the lung (VL). Fifteen newborn piglets (age <12 h, mean weight 678 g) underwent saline lung lavage to achieve a surfactant depletion. Thereafter animals were randomized to PLV (n = 8), receiving PFC PF5080 (3M, Germany) at 30 mL kg(-1), and ST (n = 7) receiving 120 mg Curosurf®. Blood gases, hemodynamics and static compliance were measured initially (baseline), immediately after ALI, and after 240 min mechanical ventilation with either technique. Subsequently all piglets were killed; the lungs were removed in toto and frozen in liquid N2. After freeze-drying the lungs were cut into lung cubes (LCs) with edge lengths of 0.7 cm, to calculate VL. All LCs were weighed and the density of the dried lung tissue was calculated. No statistically significant differences between treatment groups PLV and ST (means ± SD) were noted in body weight (676 ± 16 g versus 679 ± 17 g; P = 0.974) or lung dry weight (1.64 ± 0.29 g versus 1.79 ± 0.48 g; P = 0.48). Oxygenation index and ventilatory efficacy index did not differ significantly between both groups at any time. VL (34.28 ± 6.13 mL versus 26.22 ± 8.1 mL; P < 0.05) and the density of the dried lung tissue (48.07 ± 5.02 mg mL(-1) versus 69.07 ± 5.30 mg mL(-1); P < 0.001), however, differed significantly between the PLV and ST groups. A 4 h PLV treatment of injured ventilated small lungs increased VL by 30% and decreased lung density by 31% compared to ST treatment, indicating greater lung distension after PLV compared to ST.

  6. The use of chilled condensers for the recovery of perfluorocarbon liquid in an experimental model of perfluorocarbon vapour loss during neonatal partial liquid ventilation

    PubMed Central

    Dunster, Kimble R; Davies, Mark W; Fraser, John F

    2007-01-01

    Background Perfluorocarbon (PFC) vapour in the expired gases during partial liquid ventilation should be prevented from entering the atmosphere and recovered for potential reuse. This study aimed to determine how much PFC liquid could be recovered using a conventional humidified neonatal ventilator with chilled condensers in place of the usual expiratory ventilator circuit and whether PFC liquid could be recovered when using the chilled condensers at the ventilator exhaust outlet. Methods Using a model lung, perfluorocarbon vapour loss during humidified partial liquid ventilation of a 3.5 kg infant was approximated. For each test 30 mL of FC-77 was infused into the model lung. Condensers were placed in the expiratory limb of the ventilator circuit and the amounts of PFC (FC-77) and water recovered were measured five times. This was repeated with the condensers placed at the ventilator exhaust outlet. Results When the condensers were used as the expiratory limb, the mean (± SD) volume of FC77 recovered was 16.4 mL (± 0.18 mL). When the condensers were connected to the ventilator exhaust outlet the mean (± SD) volume of FC-77 recovered was 7.6 mL (± 1.14 mL). The volume of FC-77 recovered was significantly higher when the condenser was used as an expiratory limb. Conclusion Using two series connected condensers in the ventilator expiratory line 55% of PFC liquid (FC-77) can be recovered during partial liquid ventilation without altering the function of the of the ventilator circuit. This volume of PFC recovered was just over twice that recovered with the condensers connected to the ventilator exhaust outlet. PMID:17537270

  7. Effect of partial liquid ventilation on pulmonary vascular permeability and edema after experimental acute lung injury.

    PubMed

    Lange, N R; Kozlowski, J K; Gust, R; Shapiro, S D; Schuster, D P

    2000-07-01

    We evaluated the effects of partial liquid ventilation (PLV) with two different dosages of the perfluorocarbon LiquiVent (perflubron) on pulmonary vascular permeability and edema formation after oleic acid (OA)-induced acute lung injury in dogs. We used imaging with positron emission tomography to measure fractional pulmonary blood flow, lung water concentration (LWC), and the pulmonary transcapillary escape rate (PTCER) of (68)Ga-labeled transferrin at 5 and 21 h after lung injury in five dogs undergoing conventional mechanical ventilation (CMV), five dogs undergoing low-dose PLV (perflubron at 10 ml/kg), and four dogs undergoing high dose PLV (perflubron at 30 ml/kg). A positive end-expiratory pressure of 7.5 cm H(2)O was used in all dogs. After OA (0.08 ml/kg)- induced lung injury, there were no significant differences or trends for PTCER or LWC at any time when the PLV groups were compared with the CMV group. However, lung tissue myeloperoxidase activity was significantly lower in the combined PLV group than in the CMV group (p = 0.016). We conclude that after OA-induced lung injury, the addition of PLV to CMV does not directly attenuate pulmonary vascular leak or lung water accumulation. Rather, the benefits of such treatment may be due to modifications of the inflammatory response.

  8. Perfluorocarbon-associated gas exchange (partial liquid ventilation) in respiratory distress syndrome: a prospective, randomized, controlled study.

    PubMed

    Leach, C L; Fuhrman, B P; Morin, F C; Rath, M G

    1993-09-01

    To determine the efficacy of perfluorocarbon-associated gas exchange (partial liquid ventilation) in respiratory distress syndrome. Prospective, randomized, controlled study. State University of New York at Buffalo, School of Medicine and Biomedical Sciences. Eleven premature lambs with respiratory distress syndrome, delivered by cesarean section. Five lambs were supported by conventional mechanical ventilation alone. Six lambs were switched to perfluorocarbon-associated gas exchange after 60 to 90 mins of conventional mechanical ventilation. Perfluorocarbon-associated gas exchange was accomplished by instilling a volume of liquid perfluorocarbon equivalent to normal functional residual capacity (30 mL/kg) into the trachea, performing 3 to 4 mins of tidal liquid ventilation, and, at end-expiration, with liquid functional residual capacity of 30 mL/kg remaining in the lung, reconnecting the animal to the volume ventilator for gas tidal volumes. Serial arterial blood gases and lung mechanics were measured. While receiving conventional ventilation, all animals developed progressive hypoxemia, hypercarbia, and acidosis. However, in the perfluorocarbon-associated gas exchange group, within 5 mins of the initiation of perfluorocarbon-associated gas exchange, mean PaO2 increased four-fold, from 59 +/- 6 torr (7.9 +/- 0.8 kPa) during conventional ventilation to 250 +/- 28 torr (33.3 +/- 3.7 kPa; p < .05) during perfluorocarbon-associated gas exchange, and this increase was sustained at 60 mins of perfluorocarbon-associated gas exchange (268 +/- 38 torr; 35.7 +/- 5.1 kPa; p < .05). Mean PaCO2 decreased progressively from 62 +/- 4 torr (8.3 +/- 0.5 kPa) during conventional ventilation to 38 +/- 3.3 torr (5.1 +/- 0.4 kPa) at 60 mins of perfluorocarbon-associated gas exchange (p < .05). Mean pH concomitantly increased. Dynamic compliance increased three-fold within 15 mins of instituting perfluorocarbon-associated gas exchange, from 0.31 +/- 0.02 mL/cm H2O during conventional

  9. Time-dependency of improvements in arterial oxygenation during partial liquid ventilation in experimental acute respiratory distress syndrome

    PubMed Central

    Max, Martin; Kuhlen, Ralf; Dembinski, Rolf; Rossaint, Rolf

    2000-01-01

    Background: The mechanisms by which partial liquid ventilation (PLV) can improve gas exchange in acute lung injury are still unclear. Therefore, we examined the time- and dose-dependency of the improvements in arterial oxygen tension (PaO2) due to PLV in eight pigs with experimental lung injury, in order to discriminate increases due to oxygen dissolved in perfluorocarbon before its intrapulmonary instillation from a persistent diffusion of the respiratory gas through the liquid column. Results: Application of four sequential doses of perfluorocarbon resulted in a dose-dependent increase in PaO2. Comparison of measurements 5 and 30 min after instillation of each dose revealed a time-dependent decrease in PaO2 for doses that approximated the functional residual capacity of the animals. Conclusion: Although oxygen dissolved in perfluorocarbon at the onset of PLV can cause a short-term improvement in arterial oxygenation, diffusion of oxygen through the liquid may not be sufficient to maintain the initially observed increase in PaO2. PMID:11056747

  10. Partial liquid ventilation for preventing death and morbidity in adults with acute lung injury and acute respiratory distress syndrome.

    PubMed

    Galvin, Imelda M; Steel, Andrew; Pinto, Ruxandra; Ferguson, Niall D; Davies, Mark W

    2013-07-23

    Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are syndromes of severe respiratory failure that are associated with substantial mortality and morbidity. Artifical ventilatory support is commonly required and may exacerbate lung injury. Partial liquid ventilation (PLV) has been proposed as a less injurious form of ventilatory support for these patients. Although PLV has been shown to improve gas exchange and to reduce inflammation in experimental models of ALI, a previous systematic review did not find any evidence to support or refute its use in humans with ALI and ARDS. The primary objective of this review was to assess whether PLV reduced mortality (at 28 d, at discharge from the intensive care unit (ICU), at discharge from hospital and at one, two and five years) in adults with ALI or ARDS when compared with conventional ventilatory support.Secondary objectives were to determine how PLV compared with conventional ventilation with regard to duration of invasive mechanical ventilation, duration of respiratory support, duration of oxygen therapy, length of ICU stay, length of hospital stay, incidence of infection, long-term cognitive impairment, long-term health related quality of life, long- term lung function, long-term morbidity costs and adverse events. The following adverse events were considered: hypoxia (arterial PO2 <80 mm Hg), pneumothorax (any air leak into the pleural space requiring therapeutic intervention), hypotension (systolic blood pressure < 90 mm Hg sustained for longer than two minutes or requiring treatment with fluids or vasoactive drugs), bradycardia (heart rate < 50 beats per minute sustained for longer than one minute or requiring therapeutic intervention) and cardiac arrest (absence of effective cardiac output). In this updated review, we searched the Cochrane Central Register of Controlled Trials (CENTRAL Issue 10, 2012, in The Cochrane Library; MEDLINE (Ovid SP, 1966 to November 2012); EMBASE (Ovid SP, 1980 to

  11. Delayed Partial Liquid Ventilation Shows no Efficacy in the Treatment of Smoke Inhalation Injury in Swine

    DTIC Science & Technology

    2001-06-01

    peak and mean airway pressures, oxygen- ation index, and rate-pressure product (a barotrauma index) and lower lung compliance and arterial partial... airway over alveolar disease in SII. barotrauma; perfluorocarbon; pigs SMOKE INHALATION INJURY (SII) accompanies thermal in- jury in up to 30% of...abnormalities by its damaging effect on airways and air spaces (alveoli and distal bronchioles). Within 2 h of injury, large areas of the airways can be denuded

  12. On the horizon: liquid ventilation.

    PubMed

    Eanes, R

    1995-02-01

    Studies in preterm animals and humans have shown that liquid ventilation is a potential alternative mode of support for neonates with respiratory failure. Perfluorochemicals have a high solubility for respiratory gases and can be instilled in the lung using lower pressures than with gas ventilation. Other potential advantages of liquid ventilation include decreased alveolar surface tension, improved pulmonary mechanics, alveolar recruitment, and the removal of pulmonary debris. This article describes in detail what liquid ventilation is, compares the physiologic effects of liquid ventilation to gas ventilation, and presents the nursing implications of this technique. A review of the recent literature on the subject is presented, including reports of laboratory and clinical experience with liquid ventilation.

  13. Effect of Surfactant and Partial Liquid Ventilation Treatment on Gas Exchange and Lung Mechanics in Immature Lambs: Influence of Gestational Age

    PubMed Central

    Rey-Santano, Carmen; Mielgo, Victoria; Gastiasoro, Elena; Valls-i-Soler, Adolfo; Murgia, Xabier

    2013-01-01

    Objectives Surfactant (SF) and partial liquid ventilation (PLV) improve gas exchange and lung mechanics in neonatal RDS. However, variations in the effects of SF and PLV with degree of lung immaturity have not been thoroughly explored. Setting Experimental Neonatal Respiratory Physiology Research Unit, Cruces University Hospital. Design Prospective, randomized study using sealed envelopes. Subjects 36 preterm lambs were exposed (at 125 or 133-days of gestational age) by laparotomy and intubated. Catheters were placed in the jugular vein and carotid artery. Interventions All the lambs were assigned to one of three subgroups given: 20 mL/Kg perfluorocarbon and managed with partial liquid ventilation (PLV), surfactant (Curosurf®, 200 mg/kg) or (3) no pulmonary treatment (Controls) for 3 h. Measurements and Main Results Cardiovascular parameters, blood gases and pulmonary mechanics were measured. In 125-day gestation lambs, SF treatment partially improved gas exchange and lung mechanics, while PLV produced significant rapid improvements in these parameters. In 133-day lambs, treatments with SF or PLV achieved similarly good responses. Neither surfactant nor PLV significantly affected the cardiovascular parameters. Conclusion SF therapy response was more effective in the older gestational age group whereas the effectiveness of PLV therapy was not gestational age dependent. PMID:23418521

  14. Liquid ventilation: a future modality?

    PubMed

    Bresnahan, M

    1999-09-01

    Liquid ventilation, an idea currently being trialled in the United States, is increasingly being discussed as a possible future trend in ventilation. A review of the available literature indicates that this treatment provides effective gas exchange and has a number of potential advantages. These include lower airway pressures, decreased alveolar surface tension, alveolar recruitment and removal of pulmonary exudate. While yet to be seen in this country, liquid ventilation may be introduced in the future. If it is, those caring for patients treated in that way will require knowledge of the mechanics and physiological changes involved, as well as the potential hazards of this modality.

  15. Combined effect of low-dose nitric oxide gas inhalation with partial liquid ventilation on hemodynamics, pulmonary function, and gas exchange in acute lung injury of newborn piglets.

    PubMed Central

    Choi, Chang Won; Hwang, Jong Hee; Chang, Yun Sil; Park, Won Soon

    2003-01-01

    We conducted a randomized animal study to determine whether there is a cumulative effect on hemodynamics, pulmonary function, and gas exchange when low-dose nitric oxide (NO) is added to partial liquid ventilation (PLV) in acute lung injury. Eighteen newborn piglets were saline-lavaged repeatedly, and randomly divided into two groups: PLV with perfluorocarbon group (n=8) and lavage only (control) group (n=10). Perfluorodecalin (30 mL/kg) was instilled into the endotracheal tube for 30 min, followed by 5-10 mL/kg/hr. Fifteen minutes after the completion of perfluorodecalin dosing, NO (10 ppm) was added to the inspiratory gas in an "on/off" manner. Perfluorodecalin instillation produced a significant improvement in gas exchange, pulmonary mechanics, shunt, and pulmonary arterial pressure (PAP). The addition of NO produced a further significant improvement in PaO2 and PAP. The "on/off" response to NO was seen apparently in PAP, PaO2, dynamic compliance, and shunt. All the variables in control group were remained at near the after-lavage levels without significant improvements until the end of the experiment. We concluded that NO might have a cumulative effect on gas exchange when combined with PLV, and this might be attributable to deceased PAP and V/Q mismatching. PMID:14676437

  16. Cardiopulmonary function and oxygen delivery during total liquid ventilation.

    PubMed

    Tsagogiorgas, Charalambos; Alb, Markus; Herrmann, Peter; Quintel, Michael; Meinhardt, Juergen P

    2011-10-01

    Total liquid ventilation (TLV) with perfluorocarbons has shown to improve cardiopulmonary function in the injured and immature lung; however there remains controversy over the normal lung. Hemodynamic effects of TLV in the normal lung currently remain undetermined. This study compared changes in cardiopulmonary and circulatory function caused by either liquid or gas tidal volume ventilation. In a prospective, controlled study, 12 non-injured anesthetized, adult New Zealand rabbits were primarily conventionally gas-ventilated (CGV). After instrumentation for continuous recording of arterial (AP), central venous (CVP), left artrial (LAP), pulmonary arterial pressures (PAP), and cardiac output (CO) animals were randomized into (1) CGV group and (2) TLV group. In the TLV group partial liquid ventilation was initiated with instillation of perfluoroctylbromide (12 ml/kg). After 15 min, TLV was established for 3 hr applying a volume-controlled, pressure-limited, time-cycled ventilation mode using a double-piston configured TLV. Controls (CGV) remained gas-ventilated throughout the experiment. During TLV, heart rate, CO, PAP, MAP, CVP, and LAP as well as derived hemodynamic variables, arterial and mixed venous blood gases, oxygen delivery, PVR, and SVR did not differ significantly compared to CGV. Liquid tidal volumes suitable for long-term TLV in non-injured rabbits do not significantly impair CO, blood pressure, and oxygen dynamics when compared to CGV. Copyright © 2011 Wiley-Liss, Inc.

  17. A regulator for pressure-controlled total-liquid ventilation.

    PubMed

    Robert, Raymond; Micheau, Philippe; Avoine, Olivier; Beaudry, Benoit; Beaulieu, Alexandre; Walti, Hervé

    2010-09-01

    Total-liquid ventilation (TLV) is an innovative experimental method of mechanical-assisted ventilation in which lungs are totally filled and then ventilated with a tidal volume of perfluorochemical liquid by using a dedicated liquid ventilator. Such a novel medical device must resemble other conventional ventilators: it must be able to conduct controlled-pressure ventilation. The objective was to design a robust controller to perform pressure-regulated expiratory flow and to implement it on our latest liquid-ventilator prototype (Inolivent-4). Numerical simulations, in vitro experiments, and in vivo experiments in five healthy term newborn lambs have demonstrated that it was efficient to generate expiratory flows while avoiding collapses. Moreover, the in vivo results have demonstrated that our liquid ventilator can maintain adequate gas exchange, normal acid-base equilibrium, and achieve greater minute ventilation, better oxygenation and CO2 extraction, while nearing flow limits. Hence, it is our suggestion to perform pressure-controlled ventilation during expiration with minute ventilation equal or superior to 140 mL x min(-1) x kg(-1) in order to ensure PaCO2 below 55 mmHg. From a clinician's point of view, pressure-controlled ventilation greatly simplifies the use of the liquid ventilator, which will certainly facilitate its introduction in intensive care units for clinical applications.

  18. 46 CFR 116.600 - Ventilation of enclosed and partially enclosed spaces.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Ventilation of enclosed and partially enclosed spaces... PASSENGERS CONSTRUCTION AND ARRANGEMENT Ventilation § 116.600 Ventilation of enclosed and partially enclosed... manner suitable for the purpose of the space. (b) A power ventilation system must be capable of...

  19. 46 CFR 116.600 - Ventilation of enclosed and partially enclosed spaces.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Ventilation of enclosed and partially enclosed spaces... PASSENGERS CONSTRUCTION AND ARRANGEMENT Ventilation § 116.600 Ventilation of enclosed and partially enclosed... manner suitable for the purpose of the space. (b) A power ventilation system must be capable of...

  20. 46 CFR 116.600 - Ventilation of enclosed and partially enclosed spaces.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Ventilation of enclosed and partially enclosed spaces... PASSENGERS CONSTRUCTION AND ARRANGEMENT Ventilation § 116.600 Ventilation of enclosed and partially enclosed... manner suitable for the purpose of the space. (b) A power ventilation system must be capable of...

  1. 46 CFR 116.600 - Ventilation of enclosed and partially enclosed spaces.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Ventilation of enclosed and partially enclosed spaces... PASSENGERS CONSTRUCTION AND ARRANGEMENT Ventilation § 116.600 Ventilation of enclosed and partially enclosed... manner suitable for the purpose of the space. (b) A power ventilation system must be capable of...

  2. Partially Ventilated Transom Flow Elevations-Unsteady Analysis

    DTIC Science & Technology

    2016-06-30

    wave elevations were measured at 24 different positions within the towing tank.. High definition video was used to capture the flow elevations for a...Transom flow wave elevations between the fully wetted and fully separated regimes are measured in waves and compared with the steady case for two different...reports for ONR Grant N00014-14-1-0606 entitled "Partially Ventilated Transom Flow Elevations -Unsteady Analysis." Please contact me with any

  3. 19. NBS SUIT LAB. STORAGE SHELF WITH LIQUID COOLING VENTILATION ...

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

    19. NBS SUIT LAB. STORAGE SHELF WITH LIQUID COOLING VENTILATION GARMENT (LCVG), SUIT GLOVES, WAIST INSERTS, UPPER AND LOWER ARMS (LEFT, FROM TOP TO BOTTOM), LOWER TORSO ASSEMBLIES (LTA) (MIDDLE RIGHT TO LOWER RIGHT). - Marshall Space Flight Center, Neutral Buoyancy Simulator Facility, Rideout Road, Huntsville, Madison County, AL

  4. 46 CFR 116.600 - Ventilation of enclosed and partially enclosed spaces.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Ventilation of enclosed and partially enclosed spaces. 116.600 Section 116.600 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER VESSELS CARRYING MORE THAN 150 PASSENGERS OR WITH OVERNIGHT ACCOMMODATIONS FOR MORE THAN 49 PASSENGERS CONSTRUCTION AND ARRANGEMENT Ventilation ...

  5. Breakdown and partial discharges in magnetic liquids

    NASA Astrophysics Data System (ADS)

    Herchl, F.; Marton, K.; Tomčo, L.; Kopčanský, P.; Timko, M.; Koneracká, M.; Kolcunová, I.

    2008-05-01

    The dielectric properties (permittivity, loss factor, dielectric breakdown strength) of magnetic liquids were investigated. The magnetic liquids were composed of magnetite particles coated with oleic acid as surfactant and dispersed in transformer oil. To determine their dielectric properties they were subjected to a uniform magnetic field at high alternating electric fields up to 14 MV m-1. Nearly constant permittivity of magnetic liquid with particle volume concentration Φ = 0.0019 as a function of electric field was observed. Magnetic liquids with concentrations Φ = 0.019 and 0.032 showed significant changes of permittivity and loss factor dependent on electric and magnetic fields. The best concentration of magnetic fluid was found at which partial current impulse magnitudes were the lowest. The breakdown strength distribution of the magnetic liquid with Φ = 0.0025 was fitted with the Duxbury-Leath, Weibull and Gauss distribution functions.

  6. Effects of respiratory rate and tidal volume on gas exchange in total liquid ventilation.

    PubMed

    Bull, Joseph L; Tredici, Stefano; Fujioka, Hideki; Komori, Eisaku; Grotberg, James B; Hirschl, Ronald B

    2009-01-01

    Using a rabbit model of total liquid ventilation (TLV), and in a corresponding theoretical model, we compared nine tidal volume-respiratory rate combinations to identify a ventilator strategy to maximize gas exchange, while avoiding choked flow, during TLV. Nine different ventilation strategies were tested in each animal (n = 12): low [LR = 2.5 breath/min (bpm)], medium (MR = 5 bpm), or high (HR = 7.5 bpm) respiratory rates were combined with a low (LV = 10 ml/kg), medium (MV = 15 ml/kg), or high (HV = 20 ml/kg) tidal volumes. Blood gases and partial pressures, perfluorocarbon gas content, and airway pressures were measured for each combination. Choked flow occurred in all high respiratory rate-high volume animals, 71% of high respiratory rate-medium volume (HRMV) animals, and 50% of medium respiratory rate-high volume (MRHV) animals but in no other combinations. Medium respiratory rate-medium volume (MRMV) resulted in the highest gas exchange of the combinations that did not induce choke. The HRMV and MRHV animals that did not choke had similar or higher gas exchange than MRMV. The theory predicted this behavior, along with spatial and temporal variations in alveolar gas partial pressures. Of the combinations that did not induce choked flow, MRMV provided the highest gas exchange. Alveolar gas transport is diffusion dominated and rapid during gas ventilation but is convection dominated and slow during TLV. Consequently, the usual alveolar gas equation is not applicable for TLV.

  7. Conventional gas ventilation, liquid-assisted high-frequency oscillatory ventilation, and tidal liquid ventilation in surfactant-treated preterm lambs.

    PubMed

    Degraeuwe, P L; Thunnissen, F B; Jansen, N J; Dormaar, J T; Dohmen, L R; Blanco, C E

    2000-11-01

    This study was designed to compare the efficacy and potential protective or injurious effects of tidal liquid ventilation (TLV), liquid-assisted high-frequency oscillatory ventilation (LA-HFOV), and high PEEP conventional mechanical ventilation (CMV) in neonatal respiratory distress syndrome. Preterm lambs (124-126 days gestation), prophylactically treated with natural surfactant, were allocated to one of the treatment modalities or to an untreated fetal control group (F), euthanised after tracheal ligation. LA-HFOV animals received an intratracheal loading dose of 5 mL x kg(-1) followed by a continuous intrapulmonary instillation of 12 mL x kg(-1);h(-1) FC-75 perfluorocarbon liquid. The ventilation strategies aimed at keeping clinically appropriate arterial blood gases for a study period of 5 hours. A histological lung injury score was calculated and semiquantitative morphometry was performed on lung tissue fixed by vascular perfusion. The alveolar-arterial pressure difference for O2 was significantly lower throughout the study in TLV compared to CMV lambs; at 1, 2, and 5 hours, oxygenation was better in TLV when compared to LA-HFOV. Total lung injury scores in TLV lambs were significantly lower than in either CMV or LA-HFOV animals, but higher when compared to F. CMV and LA-HFOV induced an excess of collapsed and overdistended alveoli, whereas in TLV alveolar expansion was normally distributed around predominantly normal alveoli. CMV and LA-HFOV, but not TLV, were associated with an excess of dilated airways. Thus, in the ovine neonatal RDS model, TLV compared favourably to either gas ventilation strategy by its more uniform ventilation, reduced lung injury, and improved gas exchange.

  8. Gas transfer model to design a ventilator for neonatal total liquid ventilation.

    PubMed

    Bonfanti, Mirko; Cammi, Antonio; Bagnoli, Paola

    2015-12-01

    The study was aimed to optimize the gas transfer in an innovative ventilator for neonatal Total Liquid Ventilation (TLV) that integrates the pumping and oxygenation functions in a non-volumetric pulsatile device made of parallel flat silicone membranes. A computational approach was adopted to evaluate oxygen (O2) and carbon dioxide (CO2) exchanges between the liquid perfluorocarbon (PFC) and the oxygenating gas, as a function of the geometrical parameter of the device. A 2D semi-empirical model was implemented to this purpose using Comsol Multiphysics to study both the fluid dynamics and the gas exchange in the ventilator. Experimental gas exchanges measured with a preliminary prototype were compared to the simulation outcomes to prove the model reliability. Different device configurations were modeled to identify the optimal design able to guarantee the desired gas transfer. Good agreement between experimental and simulation outcomes was obtained, validating the model. The optimal configuration, able to achieve the desired gas exchange (ΔpCO2 = 16.5 mmHg and ΔpO2 = 69 mmHg), is a device comprising 40 modules, 300 mm in length (total exchange area = 2.28 m(2)). With this configuration gas transfer performance is satisfactory for all the simulated settings, proving good adaptability of the device.

  9. A model of neonatal tidal liquid ventilation mechanics.

    PubMed

    Costantino, M L; Fiore, G B

    2001-09-01

    Tidal liquid ventilation (TLV) with perfluorocarbons (PFC) has been proposed to treat surfactant-deficient lungs of preterm neonates, since it may prevent pulmonary instability by abating saccular surface tension. With a previous model describing gas exchange, we showed that ventilator settings are crucial for CO(2) scavenging during neonatal TLV. The present work is focused on some mechanical aspects of neonatal TLV that were hardly studied, i.e. the distribution of mechanical loads in the lungs, which is expected to differ substantially from gas ventilation. A new computational model is presented, describing pulmonary PFC hydrodynamics, where viscous losses, kinetic energy changes and lung compliance are accounted for. The model was implemented in a software package (LVMech) aimed at calculating pressures (and approximately estimate shear stresses) within the bronchial tree at different ventilator regimes. Simulations were run taking the previous model's outcomes into account. Results show that the pressure decrease due to high saccular compliance may compensate for the increased pressure drops due to PFC viscosity, and keep airway pressure low. Saccules are exposed to pressures remarkably different from those at the airway opening; during expiration negative pressures, which may cause airway collapse, are moderate and appear in the upper airways only. Delivering the fluid with a slightly smoothed square flow wave is convenient with respect to a sine wave. The use of LVMech allows to familiarize with LV treatment management taking the lungs' mechanical load into account, consistently with a proper respiratory support.

  10. High Performance Mars Liquid Cooling and Ventilation Garment Project

    NASA Technical Reports Server (NTRS)

    Terrier, Douglas; Clayton, Ronald; Whitlock, David; Conger, Bruce

    2015-01-01

    EVA space suit mobility in micro-gravity is enough of a challenge and in the gravity of Mars, improvements in mobility will enable the suited crew member to efficiently complete EVA objectives. The idea proposed is to improve thermal efficiencies of the liquid cooling and ventilation garment (LCVG) in the torso area in order to free up the arms and legs by removing the liquid tubes currently used in the ISS EVA suit in the limbs. By using shaped water tubes that greatly increase the contact area with the skin in the torso region of the body, the heat transfer efficiency can be increased to provide the entire liquid cooling requirement and increase mobility by freeing up the arms and legs. Additional potential benefits of this approach include reduced LCVG mass, enhanced evaporation cooling, increased comfort during Mars EVA tasks, and easing of the overly dry condition in the helmet associated with the Advanced Extravehicular Mobility Unit (EMU) ventilation loop currently under development.

  11. Quantitative investigation of alveolar structures with OCT using total liquid ventilation during mechanical ventilation

    NASA Astrophysics Data System (ADS)

    Schnabel, Christian; Gaertner, Maria; Meissner, Sven; Koch, Edmund

    2012-02-01

    To develop new treatment possibilities for patients with severe lung diseases it is crucial to understand the lung function on an alveolar level. Optical coherence tomography (OCT) in combination with intravital microscopy (IVM) are used for imaging subpleural alveoli in animal models to gain information about dynamic and morphological changes of lung tissue during mechanical ventilation. The image content suitable for further analysis is influenced by image artifacts caused by scattering, refraction, reflection, and absorbance. Because the refractive index varies with each air-tissue interface in lung tissue, these effects decrease OCT image quality exceedingly. The quality of OCT images can be increased when the refractive index inside the alveoli is matched to the one of tissue via liquid-filling. Thereby, scattering loss can be decreased and higher penetration depth and tissue contrast can be achieved. To use the advantages of liquid-filling for in vivo imaging of small rodent lungs, a suitable breathing fluid (perfluorodecalin) and a special liquid respirator are necessary. Here we show the effect of liquid-filling on OCT and IVM image quality of subpleural alveoli in a mouse model.

  12. Pleural liquid and kinetic friction coefficient of mesothelium after mechanical ventilation.

    PubMed

    Bodega, Francesca; Sironi, Chiara; Porta, Cristina; Zocchi, Luciano; Agostoni, Emilio

    2015-01-15

    Volume and protein concentration of pleural liquid in anesthetized rabbits after 1 or 3h of mechanical ventilation, with alveolar pressure equal to atmospheric at end expiration, were compared to those occurring after spontaneous breathing. Moreover, coefficient of kinetic friction between samples of visceral and parietal pleura, obtained after spontaneous or mechanical ventilation, sliding in vitro at physiological velocity under physiological load, was determined. Volume of pleural liquid after mechanical ventilation was similar to that previously found during spontaneous ventilation. This finding is contrary to expectation of Moriondo et al. (2005), based on measurement of lymphatic and interstitial pressure. Protein concentration of pleural liquid after mechanical ventilation was also similar to that occurring after spontaneous ventilation. Coefficient of kinetic friction after mechanical ventilation was 0.023±0.001, similar to that obtained after spontaneous breathing.

  13. Partially exposed polymer dispersed liquid crystals for boundary layer investigations

    NASA Technical Reports Server (NTRS)

    Parmar, Devendra S.; Singh, Jag J.

    1992-01-01

    A new configuration termed partially exposed polymer dispersed liquid crystal in which the liquid crystal microdroplets dispersed in a rigid polymer matrix are partially entrapped on the free surface of the thin film deposited on a glass substrate is reported. Optical transmission characteristics of the partially exposed polymer dispersed liquid crystal thin film in response to an air flow induced shear stress field reveal its potential as a sensor for gas flow and boundary layer investigations.

  14. Partial Support Ventilation and Mitochondrial-Targeted Antioxidants Protect against Ventilator-Induced Decreases in Diaphragm Muscle Protein Synthesis.

    PubMed

    Hudson, Matthew B; Smuder, Ashley J; Nelson, W Bradley; Wiggs, Michael P; Shimkus, Kevin L; Fluckey, James D; Szeto, Hazel H; Powers, Scott K

    2015-01-01

    Mechanical ventilation (MV) is a life-saving intervention in patients in respiratory failure. Unfortunately, prolonged MV results in the rapid development of diaphragm atrophy and weakness. MV-induced diaphragmatic weakness is significant because inspiratory muscle dysfunction is a risk factor for problematic weaning from MV. Therefore, developing a clinical intervention to prevent MV-induced diaphragm atrophy is important. In this regard, MV-induced diaphragmatic atrophy occurs due to both increased proteolysis and decreased protein synthesis. While efforts to impede MV-induced increased proteolysis in the diaphragm are well-documented, only one study has investigated methods of preserving diaphragmatic protein synthesis during prolonged MV. Therefore, we evaluated the efficacy of two therapeutic interventions that, conceptually, have the potential to sustain protein synthesis in the rat diaphragm during prolonged MV. Specifically, these experiments were designed to: 1) determine if partial-support MV will protect against the decrease in diaphragmatic protein synthesis that occurs during prolonged full-support MV; and 2) establish if treatment with a mitochondrial-targeted antioxidant will maintain diaphragm protein synthesis during full-support MV. Compared to spontaneously breathing animals, full support MV resulted in a significant decline in diaphragmatic protein synthesis during 12 hours of MV. In contrast, diaphragm protein synthesis rates were maintained during partial support MV at levels comparable to spontaneous breathing animals. Further, treatment of animals with a mitochondrial-targeted antioxidant prevented oxidative stress during full support MV and maintained diaphragm protein synthesis at the level of spontaneous breathing animals. We conclude that treatment with mitochondrial-targeted antioxidants or the use of partial-support MV are potential strategies to preserve diaphragm protein synthesis during prolonged MV.

  15. Partial Support Ventilation and Mitochondrial-Targeted Antioxidants Protect against Ventilator-Induced Decreases in Diaphragm Muscle Protein Synthesis

    PubMed Central

    Hudson, Matthew B.; Smuder, Ashley J.; Nelson, W. Bradley; Wiggs, Michael P.; Shimkus, Kevin L.; Fluckey, James D.; Szeto, Hazel H.; Powers, Scott K.

    2015-01-01

    Mechanical ventilation (MV) is a life-saving intervention in patients in respiratory failure. Unfortunately, prolonged MV results in the rapid development of diaphragm atrophy and weakness. MV-induced diaphragmatic weakness is significant because inspiratory muscle dysfunction is a risk factor for problematic weaning from MV. Therefore, developing a clinical intervention to prevent MV-induced diaphragm atrophy is important. In this regard, MV-induced diaphragmatic atrophy occurs due to both increased proteolysis and decreased protein synthesis. While efforts to impede MV-induced increased proteolysis in the diaphragm are well-documented, only one study has investigated methods of preserving diaphragmatic protein synthesis during prolonged MV. Therefore, we evaluated the efficacy of two therapeutic interventions that, conceptually, have the potential to sustain protein synthesis in the rat diaphragm during prolonged MV. Specifically, these experiments were designed to: 1) determine if partial-support MV will protect against the decrease in diaphragmatic protein synthesis that occurs during prolonged full-support MV; and 2) establish if treatment with a mitochondrial-targeted antioxidant will maintain diaphragm protein synthesis during full-support MV. Compared to spontaneously breathing animals, full support MV resulted in a significant decline in diaphragmatic protein synthesis during 12 hours of MV. In contrast, diaphragm protein synthesis rates were maintained during partial support MV at levels comparable to spontaneous breathing animals. Further, treatment of animals with a mitochondrial-targeted antioxidant prevented oxidative stress during full support MV and maintained diaphragm protein synthesis at the level of spontaneous breathing animals. We conclude that treatment with mitochondrial-targeted antioxidants or the use of partial-support MV are potential strategies to preserve diaphragm protein synthesis during prolonged MV. PMID:26361212

  16. A prototype of volume-controlled tidal liquid ventilator using independent piston pumps.

    PubMed

    Robert, Raymond; Micheau, Philippe; Cyr, Stéphane; Lesur, Olivier; Praud, Jean-Paul; Walti, Hervé

    2006-01-01

    Liquid ventilation using perfluorochemicals (PFC) offers clear theoretical advantages over gas ventilation, such as decreased lung damage, recruitment of collapsed lung regions, and lavage of inflammatory debris. We present a total liquid ventilator designed to ventilate patients with completely filled lungs with a tidal volume of PFC liquid. The two independent piston pumps are volume controlled and pressure limited. Measurable pumping errors are corrected by a programmed supervisor module, which modifies the inserted or withdrawn volume. Pump independence also allows easy functional residual capacity modifications during ventilation. The bubble gas exchanger is divided into two sections such that the PFC exiting the lungs is not in contact with the PFC entering the lungs. The heating system is incorporated into the metallic base of the gas exchanger, and a heat-sink-type condenser is placed on top of the exchanger to retrieve PFC vapors. The prototype was tested on 5 healthy term newborn lambs (<5 days old). The results demonstrate the efficiency and safety of the prototype in maintaining adequate gas exchange, normal acido-basis equilibrium, and cardiovascular stability during a short, 2-hour total liquid ventilator. Airway pressure, lung volume, and ventilation scheme were maintained in the targeted range.

  17. Liquid ventilator for ultrafast hypothermia induction in juvenile lambs: Preliminary results.

    PubMed

    Nadeau, Mathieu; Sage, Michaël; Kohlhauer, Matthias; Robert, Raymond; Vandamne, Jonathan; Mousseau, Julien; Tissier, Renaud; Praud, Jean-Paul; Walti, Hervé; Micheau, Philippe

    2015-08-01

    Total liquid ventilation (TLV) is an emerging mechanical ventilation technique. In this technique, the lungs are filled with liquid perfluorocarbons (PFC) and a liquid ventilator assures ventilation by periodically renewing a volume of oxygenated, CO2 freed and temperature controlled PFC. A huge difference between conventional mechanical ventilation and TLV relates to the fact that PFCs are about 1500 times denser than air. Thus, the PFCs filled lungs turn into an efficient heat exchanger with the circulating blood. One of the most appealing utilization of the lungs as a heat exchanger in TLV is for ultrafast induction of mild therapeutic hypothermia (MTH) for neuroprotection and cardioprotection after ischemia-reperfusion injuries. This study aimed to perform ultrafast MTH induction by TLV in animals up to 25 kg, then perform a fast post-hypothermic rewarming while maintaining proper ventilation. A thermal model of the lamb and liquid ventilator was developed to predict the dynamic and the control strategy to adopt for MTH induction. Two juvenile lambs were instrumented with temperature sensors in the femoral artery, pulmonary artery, oesophagus, right eardrum and rectum. After stabilization in conventional mechanical ventilation, TLV was initiated with ultrafast MTH induction, followed by posthypothermic rewarming. Preliminary results in the two juvenile lambs reveal that the liquid ventilator Inolivent-6.0 can induce MTH by TLV in less than 2.5 min for systemic arterial blood and in less than 10 min for venous return, esophagus and eardrum. Rectal temperature reached MTH in respectively 19.4 and 17.0 min for both lambs. Experimental results were consistent with the model predictions. Moreover, blood gas analysis exhibited that the gas exchange in the lungs was maintained adequately for the entire experiments.

  18. Ventilation.

    PubMed

    Turner, W A; Bearg, D W; Brennan, T

    1995-01-01

    This chapter begins with an overview of the history of ventilation guidelines, which has led to the guidelines that are in effect today. Of particular interest is the most recent return in the past 5 years to ventilation rates that more closely reflect a mean or average of the range of guidelines that have existed over the past century. OSHA's and the EPA's recognition of the need to operate ventilation systems in buildings in an accountable manner is also of note. Of even more interest is the resurgence of the concept of minimum mixing and once-through ventilation air that has been pursued in parts of Northern Europe for the past 10 years, and in a school that is being designed with this concept in New Hampshire. In addition, the design concept of equipping office buildings with low pressure drop high efficiency particle filtration to remove fine particles from all of the air that is supplied to the occupants is being used increasingly in the U.S. This chapter also presents an overview of the various types of ventilation systems found in homes and commercial office buildings and the common indoor air quality problems that may be associated with them. It also offers an overview of common HVAC evaluation techniques that can be used to determine if a ventilation system is performing in a manner that makes sense for the use of the space and the needs of the occupants. Are the occupants receiving a reasonable supply of outdoor air? Is the air that they receive of reasonable quality? Are obvious pollutants being exhausted? Ventilation systems have become extremely complex and more difficult to run and maintain over the past 40 years. This trend will continue to drive the need for professionally maintained HVAC equipment that is serviced and run by individuals who are accountable for the quality of the air that the system delivers.

  19. Software for real-time control of a tidal liquid ventilator.

    PubMed

    Heckman, J L; Hoffman, J; Shaffer, T H; Wolfson, M R

    1999-01-01

    The purpose of this project was to develop and test computer software and control algorithms designed to operate a tidal liquid ventilator. The tests were executed on a 90-MHz Pentium PC with 16 MB RAM and a prototype liquid ventilator. The software was designed using Microsoft Visual C++ (Ver. 5.0) and the Microsoft Foundation Classes. It uses a graphic user interface, is multithreaded, runs in real time, and has a built-in simulator that facilitates user education in liquid-ventilation principles. The operator can use the software to specify ventilation parameters such as the frequency of ventilation, the tidal volume, and the inspiratory-expiratory time ratio. Commands are implemented via control of the pump speed and by setting the position of two two-way solenoid-controlled valves. Data for use in monitoring and control are gathered by analog-to-digital conversion. Control strategies are implemented to maintain lung volumes and airway pressures within desired ranges, according to limits set by the operator. Also, the software allows the operator to define the shape of the flow pulse during inspiration and expiration, and to optimize perfluorochemical liquid transfer while minimizing airway pressures and maintaining the desired tidal volume. The operator can stop flow during inspiration and expiration to measure alveolar pressures. At the end of expiration, the software stores all user commands and 30 ventilation parameters into an Excel spreadsheet for later review and analysis. Use of these software and control algorithms affords user-friendly operation of a tidal liquid ventilator while providing precise control of ventilation parameters.

  20. Numerical investigation of turbulent bubbly wakes created by the ventilated partial cavity

    NASA Astrophysics Data System (ADS)

    Xiang, Min; Zhang, WeiHua; Cheung, S. C. P.; Tu, JiYuan

    2012-02-01

    This paper presents a numerical study on the turbulent bubbly wakes created by the ventilated partial cavity. A semi-empirical approach is introduced to model the discrete interface of the ventilated cavity and its complex gas leakage rate induced by the local turbulent shear stress. Based on the Eulerian-Eulerian two-fluid modeling framework, a population balance approach based on MUltiple-SIze-Group (MUSIG) model is incorporated to simulate the size evolution of the sheared off microbubbles and its complex interactions with the two-phase flow structure in the wake region. Numerical predictions at various axial locations downstream of the test body were in satisfactory agreement with the experimental measurements. The captured bubbly wake structure illustrates that the bubbles may disperse as a twin-vortex tube driven by gravity effect. The predicted Sauter mean bubble diameter has confirmed the dominance of the coleascense process in the axial direction. As the bubbles develop downstream, the coleascense and breakup rate gradually reach balance, resulting in the stable bubble diameter. A close examination of the flow structures, gas void fraction distributions and the bubble size evolution provides valuable insights into the complex physical phenomenon induced by ventilated cavity.

  1. A perfluorochemical loss/restoration (L/R) system for tidal liquid ventilation.

    PubMed

    Libros, R; Philips, C M; Wolfson, M R; Shaffer, T H

    2000-01-01

    Tidal liquid ventilation is the transport of dissolved respiratory gases via volume exchange of perfluorochemical (PFC) liquid to and from the PFC-filled lung. All gas-liquid surface tension is eliminated, increasing compliance and providing lung protection due to lower inflation pressures. Tidal liquid ventilation is achieved by cycling fluid from a reservoir to and from the lung by a ventilator. Current approaches are microprocessor-based with feedback control. During inspiration, warmed oxygenated PFC liquid is pumped from a fluid reservoir/gas exchanger into the lung. PFC fluid is conserved by condensing (60-80% efficiency) vapor in the expired gas. A feedback-control system was developed to automatically replace PFC lost due to condenser inefficiency. This loss/restoration (L/R) system consists of a PFC-vapor thermal detector (+/- 2.5%), pneumatics, amplifiers, a gas flow detector (+/- 1%), a PFC pump (+/- 5%), and a controller. Gravimetric studies of perflubron loss from a flask due to evaporation were compared with experimental L/R results and found to be within +/- 1.4%. In addition, when L/R studies were conducted with a previously reported liquid ventilation system over a four-hour period, the L/R system maintained system perflubron volume to within +/- 1% of prime volume and 11.5% of replacement volume, and the difference between experimental PFC loss and that of the L/R system was 1.8 mL/hr. These studies suggest that the PFC L/R system may have significant economic (appropriate dosing for PFC loss) as well as physiologic (maintenance of PFC inventory in the lungs and liquid ventilator) impact on liquid ventilation procedures.

  2. Liquid dynamics in partially crystalline glycerol

    NASA Astrophysics Data System (ADS)

    Sanz, Alejandro; Niss, Kristine

    2017-01-01

    We present a dielectric study on the dynamics of supercooled glycerol during crystallization. We explore the transformation into a solid phase in real time by monitoring the temporal evolution of the amplitude of the dielectric signal. Neither the initial nucleation nor the crystal growth influences the liquid dynamics visibly. For one of the samples studied, a tiny fraction of glycerol remained in the disordered state after the end of the transition. We examined the nature of the α relaxation in this frustrated crystal and find that it is virtually identical to the bulk dynamics. In addition, we have found no evidence that supercooled glycerol transforms into a peculiar phase in which either a new solid amorphous state or nano-crystals dispersed in a liquid matrix are formed.

  3. Total liquid ventilation provides superior respiratory support to conventional mechanical ventilation in a large animal model of severe respiratory failure.

    PubMed

    Pohlmann, Joshua R; Brant, David O; Daul, Morgan A; Reoma, Junewai L; Kim, Anne C; Osterholzer, Kathryn R; Johnson, Kent J; Bartlett, Robert H; Cook, Keith E; Hirschl, Ronald B

    2011-01-01

    Total liquid ventilation (TLV) has the potential to provide respiratory support superior to conventional mechanical ventilation (CMV) in the acute respiratory distress syndrome (ARDS). However, laboratory studies are limited to trials in small animals for no longer than 4 hours. The objective of this study was to compare TLV and CMV in a large animal model of ARDS for 24 hours. Ten sheep weighing 53 ± 4 (SD) kg were anesthetized and ventilated with 100% oxygen. Oleic acid was injected into the pulmonary circulation until PaO2:FiO2 ≤ 60 mm Hg, followed by transition to a protective CMV protocol (n = 5) or TLV (n = 5) for 24 hours. Pathophysiology was recorded, and the lungs were harvested for histological analysis. Animals treated with CMV became progressively hypoxic and hypercarbic despite maximum ventilatory support. Sheep treated with TLV maintained normal blood gases with statistically greater PO2 (p < 10(-9)) and lower PCO2 (p < 10(-3)) than the CMV group. Survival at 24 hours in the TLV and CMV groups were 100% and 40%, respectively (p < 0.05). Thus, TLV provided gas exchange superior to CMV in this laboratory model of severe ARDS.

  4. Total Liquid Ventilation Provides Superior Respiratory Support to Conventional Mechanical Ventilation in a Large Animal Model of Severe Respiratory Failure

    PubMed Central

    Pohlmann, Joshua R; Brant, David O; Daul, Morgan A; Reoma, Junewai L; Kim, Anne C; Osterholzer, Kathryn R; Johnson, Kent J; Bartlett, Robert H; Cook, Keith E; Hirschl, Ronald B

    2011-01-01

    Total liquid ventilation (TLV) has the potential to provide respiratory support superior to conventional mechanical ventilation (CMV) in the acute respiratory distress syndrome (ARDS). However, laboratory studies are limited to trials in small animals for no longer than 4 hours. The objective of this study was to compare TLV and CMV in a large animal model of ARDS for 24 hours. Ten sheep weighing 53 ± 4 (SD) kg were anesthetized and ventilated with 100% oxygen. Oleic acid was injected into the pulmonary circulation until PaO2:FiO2 ≥ 60 mmHg, followed by transition to a protective CMV protocol (n=5) or TLV (n=5) for 24 hours. Pathophysiology was recorded and the lungs were harvested for histological analysis. Animals treated with CMV became progressively hypoxic and hypercarbic despite maximum ventilatory support. Sheep treated with TLV maintained normal blood gases with statistically greater PO2 (p<10−9) and lower PCO2 (p < 10−3) than the CMV group. Survival at 24 hours in the TLV and CMV groups were 100% and 40% respectively (p< 0.05). Thus, TLV provided gas exchange superior to CMV in this laboratory model of severe ARDS. PMID:21084968

  5. Core body temperature control by total liquid ventilation using a virtual lung temperature sensor.

    PubMed

    Nadeau, Mathieu; Micheau, Philippe; Robert, Raymond; Avoine, Olivier; Tissier, Renaud; Germim, Pamela Samanta; Vandamme, Jonathan; Praud, Jean-Paul; Walti, Herve

    2014-12-01

    In total liquid ventilation (TLV), the lungs are filled with a breathable liquid perfluorocarbon (PFC) while a liquid ventilator ensures proper gas exchange by renewal of a tidal volume of oxygenated and temperature-controlled PFC. Given the rapid changes in core body temperature generated by TLV using the lung has a heat exchanger, it is crucial to have accurate and reliable core body temperature monitoring and control. This study presents the design of a virtual lung temperature sensor to control core temperature. In the first step, the virtual sensor, using expired PFC to estimate lung temperature noninvasively, was validated both in vitro and in vivo. The virtual lung temperature was then used to rapidly and automatically control core temperature. Experimentations were performed using the Inolivent-5.0 liquid ventilator with a feedback controller to modulate inspired PFC temperature thereby controlling lung temperature. The in vivo experimental protocol was conducted on seven newborn lambs instrumented with temperature sensors at the femoral artery, pulmonary artery, oesophagus, right ear drum, and rectum. After stabilization in conventional mechanical ventilation, TLV was initiated with fast hypothermia induction, followed by slow posthypothermic rewarming for 1 h, then by fast rewarming to normothermia and finally a second fast hypothermia induction phase. Results showed that the virtual lung temperature was able to provide an accurate estimation of systemic arterial temperature. Results also demonstrate that TLV can precisely control core body temperature and can be favorably compared to extracorporeal circulation in terms of speed.

  6. Improved OCT imaging of lung tissue using a prototype for total liquid ventilation

    NASA Astrophysics Data System (ADS)

    Schnabel, Christian; Meissner, Sven; Koch, Edmund

    2011-06-01

    Optical coherence tomography (OCT) is used for imaging subpleural alveoli in animal models to gain information about dynamic and morphological changes of lung tissue during mechanical ventilation. The quality of OCT images can be increased if the refraction index inside the alveoli is matched to the one of tissue via liquid-filling. Thereby, scattering loss can be decreased and higher penetration depth and tissue contrast can be achieved. Until now, images of liquid-filled lungs were acquired in isolated and fixated lungs only, so that an in vivo measurement situation is not present. To use the advantages of liquid-filling for in vivo imaging of small rodent lungs, it was necessary to develop a liquid ventilator. Perfluorodecalin, a perfluorocarbon, was selected as breathing fluid because of its refraction index being similar to the one of water and the high transport capacity for carbon dioxide and oxygen. The setup is characterized by two independent syringe pumps to insert and withdraw the fluid into and from the lung and a custom-made control program for volume- or pressure-controlled ventilation modes. The presented results demonstrate the liquid-filling verified by optical coherence tomography and intravital microscopy (IVM) and the advantages of liquid-filling to OCT imaging of subpleural alveoli.

  7. A prototype of a liquid ventilator using a novel hollow-fiber oxygenator in a rabbit model.

    PubMed

    Tredici, Stefano; Komori, Eisaku; Funakubo, Akio; Brant, David O; Bull, Joseph L; Bartlett, Robert H; Hirschl, Ronald B

    2004-10-01

    A functional total liquid ventilator should be simple in design to minimize operating errors and have a low priming volume to minimize the amount of perfluorocarbon needed. Closed system circuits using a membrane oxygenator have partially met these requirements but have high resistance to perfluorocarbon flow and high priming volume. To further this goal, a single piston prototype ventilator with a low priming volume and a new high-efficiency hollow-fiber oxygenator in a circuit with a check valve flow control system was developed. Prospective, controlled animal laboratory study. Research facility at a university medical center. Seven anesthetized, paralyzed, normal New Zealand rabbits The prototype oxygenator, consisting of cross-wound silicone hollow fibers with a surface area of 1.5 m2 with a priming volume of 190 mL, was tested in a bench-top model followed by an in vivo rabbit model. Total liquid ventilation was performed for 3 hrs with 20 mL.kg(-1) initial fill volume, 17.5-20 mL.kg(-1) tidal volume, respiratory rate of 5 breaths/min, inspiratory/expiratory ratio 1:2, and countercurrent sweep gas of 100% oxygen. Bench top experiments demonstrated 66-81% elimination of CO2 and 0.64-0.76 mL.min(-1) loss of perfluorocarbon across the fibers. No significant changes in PaCO2 and PaO2 were observed. Dynamic airway pressures were in a safe range in which ventilator lung injury or airway closure was unlikely (3.6 +/- 0.5 and -7.8 +/- 0.3 cm H2O, respectively, for mean peak inspiratory pressure and mean end expiratory pressure). No leakage of perfluorocarbon was noted in the new silicone fiber gas exchange device. Estimated in vivo perfluorocarbon loss from the device was 1.2 mL.min(-1). These data demonstrate the ability of this novel single-piston, nonporous hollow silicone fiber oxygenator to adequately support gas exchange, allowing successful performance of total liquid ventilation.

  8. Four-dimensional optical coherence tomography imaging of total liquid ventilated rats

    NASA Astrophysics Data System (ADS)

    Kirsten, Lars; Schnabel, Christian; Gaertner, Maria; Koch, Edmund

    2013-06-01

    Optical coherence tomography (OCT) can be utilized for the spatially and temporally resolved visualization of alveolar tissue and its dynamics in rodent models, which allows the investigation of lung dynamics on the microscopic scale of single alveoli. The findings could provide experimental input data for numerical simulations of lung tissue mechanics and could support the development of protective ventilation strategies. Real four-dimensional OCT imaging permits the acquisition of several OCT stacks within one single ventilation cycle. Thus, the entire four-dimensional information is directly obtained. Compared to conventional virtual four-dimensional OCT imaging, where the image acquisition is extended over many ventilation cycles and is triggered on pressure levels, real four-dimensional OCT is less vulnerable against motion artifacts and non-reproducible movement of the lung tissue over subsequent ventilation cycles, which widely reduces image artifacts. However, OCT imaging of alveolar tissue is affected by refraction and total internal reflection at air-tissue interfaces. Thus, only the first alveolar layer beneath the pleura is visible. To circumvent this effect, total liquid ventilation can be carried out to match the refractive indices of lung tissue and the breathing medium, which improves the visibility of the alveolar structure, the image quality and the penetration depth and provides the real structure of the alveolar tissue. In this study, a combination of four-dimensional OCT imaging with total liquid ventilation allowed the visualization of the alveolar structure in rat lung tissue benefiting from the improved depth range beneath the pleura and from the high spatial and temporal resolution.

  9. Evaluation of Mechanical Ventilator Use with Liquid Oxygen Systems

    DTIC Science & Technology

    2017-02-22

    Nasilowski J , Przybylowski T , Zielinski J , Chazan R . Comparing supplementary oxygen benefits from a portable oxygen concentrator and a liquid oxygen...Rodriquez Jr., MSc, RRT; Richard Branson, MSc, RRT; John-Michael Fowler , BSN, RN; Matthew Worsham, RT; Nicole Alston, RT; Dina Gomaa, MSc, RRT...Branson, MSc, RRT; John-Michael Fowler , BSN, RN; Matthew Worsham, RT; Nicole Alston, RT; Dina Gomaa, MSc, RRT; James Woods, MSc, RRT 5d. PROJECT

  10. Near Axisymmetric Partial Wetting Using Interface-Localized Liquid Dielectrophoresis.

    PubMed

    Brabcova, Zuzana; McHale, Glen; Wells, Gary George; Brown, Carl V; Newton, Michael Ian; Edwards, Andrew M J

    2016-10-03

    The wetting of solid surfaces can be modified by altering the surface free energy balance between the solid, liquid, and vapour phases. Liquid dielectrophoresis (L-DEP) can produce wetting on normally non-wetting surfaces, without modification of the surface topography or chemistry. L-DEP is a bulk force acting on the dipoles of a dielectric liquid and is not normally considered to be a localized effect acting at the interface between the liquid and a solid or other fluid. However, if this force is induced by a non-uniform electric field across a solid-liquid interface, it can be used to enhance and control the wetting of a dielectric liquid. Recently, it was reported theoretically and experimentally that this approach can cause a droplet of oil to spread along parallel interdigitated electrodes thus forming a stripe of liquid. Here we show that by using spiral shaped electrodes actuated with four 90º successive phase shifted signals, a near axisymmetric spreading of droplets can be achieved. Experimental observations show that the induced wetting can achieve film formation, an effect not possible with electrowetting. We show that the spreading is reversible thus enabling a wide range of partial wetting droplet states to be achieved in a controllable manner. Furthermore, we find that the cosine of the contact angle has a quadratic dependence on applied voltage during spreading and deduce a scaling law for the dependence of the strength of the effect on the electrode size. .

  11. Partial coalescence of sessile drops with different liquids

    NASA Astrophysics Data System (ADS)

    Borcia, Rodica; Bestehorn, Michael

    2014-11-01

    We examine numerically the interaction between two deformable drops consisting of two perfectly miscible liquids sitting on a solid substrate under a given contact angle. Driven by solutal Marangoni forces, several distinct coalescence regimes are achieved after the droplets collision. Phase diagrams for different control parameters are emphasized, which give predictions about drop behavior along the solid substrates, control of various interfacial effects, manipulations of tiny droplets in micro- and nano-fluidic devices without power supply, design of droplets or cleaning surfaces. This work was partially supported by Deutsche Forschungsgemeinschaft (DFG) under the project ``Dynamics of interfaces between drops with miscible liquids''.

  12. A microprocessor-controlled tracheal insufflation-assisted total liquid ventilation system.

    PubMed

    Parker, James Courtney; Sakla, Adel; Donovan, Francis M; Beam, David; Chekuri, Annu; Al-Khatib, Mohammad; Hamm, Charles R; Eyal, Fabien G

    2009-09-01

    A prototype time cycled, constant volume, closed circuit perfluorocarbon (PFC) total liquid ventilator system is described. The system utilizes microcontroller-driven display and master control boards, gear motor pumps, and three-way solenoid valves to direct flow. A constant tidal volume and functional residual capacity (FRC) are maintained with feedback control using end-expiratory and end-inspiratory stop-flow pressures. The system can also provide a unique continuous perfusion (bias flow, tracheal insufflation) through one lumen of a double-lumen endotracheal catheter to increase washout of dead space liquid. FRC and arterial blood gases were maintained during ventilation with Rimar 101 PFC over 2-3 h in normal piglets and piglets with simulated pulmonary edema induced by instillation of albumin solution. Addition of tracheal insufflation flow significantly improved the blood gases and enhanced clearance of instilled albumin solution during simulated edema.

  13. A Partial Equilibrium Theory for Drops and Capillary Liquids

    SciTech Connect

    Searcy, Alan W.; Beruto, Dario T.; Barberis, Fabrizio

    2006-10-26

    The two-century old theory of Young and Laplace retains apowerful influence on surface and interface studies because itquantitatively predicts the height of rise of capillary liquids from thecontact angles of drops. But the classical theory does not acknowledgethat equilibrium requires separate minimization of partial free energiesof one-component liquids bonded to immiscible solids. We generalize atheorem of Gibbs and Curie to obtain a partial equilibrium (PE) theorythat does so and that also predicts the height of capillary rise fromcontact angles of drops. Published observations and our own measurementsof contact angles of water bonded to glass and Teflon surfaces supportthe conclusion of PE theory that contact angles of meniscuses and ofdrops are different dependent variables. PE theory provides thermodynamicand kinetic guidance to nanoscale processes that the classical theoryobscures, as illustrated by examples in our concludingsection.

  14. Skin friction measurement with partially exposed polymer dispersed liquid crystals

    NASA Technical Reports Server (NTRS)

    Parmar, D. S.; Holmes, H. K.

    1993-01-01

    Partially exposed polymer dispersed liquid crystal thin film (10-25 microns) deposited on a flat glass substrate has been used for the first time to measure skin friction. Utilizing the shear-stress-induced director reorientation in the partially exposed liquid-crystal droplets, optical transmission under crossed polarization has been measured as a function of the air flow differential pressure. Direct measurement of the skin friction with a skin friction drag balance, under the same aerodynamic conditions, lets us correlate the skin friction with optical transmission. This provides a unique technique for the direct measurement of skin friction from the transmitted light intensity. The results are in excellent agreement with the model suggested in this paper.

  15. 46 CFR 177.600 - Ventilation of enclosed and partially enclosed spaces.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    .... (d) An exhaust duct over a frying vat or a grill must be of at least 11 U.S. Standard Gauge steel. (e) Combustibles and other foreign materials are not allowed within ventilation ducts. However, metal piping and electrical wiring installed in a metal protective enclosure may be installed within ventilation...

  16. Neonatal total liquid ventilation: is low-frequency forced oscillation technique suitable for respiratory mechanics assessment?

    PubMed

    Bossé, Dominick; Beaulieu, Alexandre; Avoine, Olivier; Micheau, Philippe; Praud, Jean-Paul; Walti, Hervé

    2010-08-01

    This study aimed to implement low-frequency forced oscillation technique (LFFOT) in neonatal total liquid ventilation (TLV) and to provide the first insight into respiratory impedance under this new modality of ventilation. Thirteen newborn lambs, weighing 2.5 + or - 0.4 kg (mean + or - SD), were premedicated, intubated, anesthetized, and then placed under TLV using a specially design liquid ventilator and a perfluorocarbon. The respiratory mechanics measurements protocol was started immediately after TLV initiation. Three blocks of measurements were first performed: one during initial respiratory system adaptation to TLV, followed by two other series during steady-state conditions. Lambs were then divided into two groups before undergoing another three blocks of measurements: the first group received a 10-min intravenous infusion of salbutamol (1.5 microg x kg(-1) x min(-1)) after continuous infusion of methacholine (9 microg x kg(-1) x min(-1)), while the second group of lambs was chest strapped. Respiratory impedance was measured using serial single-frequency tests at frequencies ranging between 0.05 and 2 Hz and then fitted with a constant-phase model. Harmonic test signals of 0.2 Hz were also launched every 10 min throughout the measurement protocol. Airway resistance and inertance were starkly increased in TLV compared with gas ventilation, with a resonant frequency < or = 1.2 Hz. Resistance of 0.2 Hz and reactance were sensitive to bronchoconstriction and dilation, as well as during compliance reduction. We report successful implementation of LFFOT to neonatal TLV and present the first insight into respiratory impedance under this new modality of ventilation. We show that LFFOT is an effective tool to track respiratory mechanics under TLV.

  17. Visualizing dissolved oxygen transport for liquid ventilation in an in vitro model of the human airways

    NASA Astrophysics Data System (ADS)

    Janke, T.; Bauer, K.

    2017-04-01

    Up until to now, the measurement of dissolved oxygen concentrations during liquid ventilation is limited to the determination of averaged concentrations of the liquid entering or leaving the body. The work presented in this paper aims to extend the possible measurement techniques in the research of liquid ventilation. Therefore optical measurements of the dissolved oxygen concentration, using a luminescent sensor dye, are performed. The preparation of a suitable sensor liquid, based on the metal complex Dichlorotris(1,10)-(phenanthroline)ruthenium(II), is presented. A transparent simplified human lung geometry is used for conducting the experiments. Inspiratory as well as expiratory flow at three different constant flow rates is investigated, covering the flow regimes \\text{Re}=83 -333 and \\text{Pe}=33 300 -133 000. The applied measurement technique is capable to reveal distinctive concentration patterns during inspiration and expiration caused by the laminar flow characteristics. Allowing a sufficiently long flow duration, local concentration inhomogeneities disappear and an exponential rise and decay of the mean values can be observed for inspiration and expiration.

  18. A partial equilibrium theory for liquids bonded to immobile solids.

    PubMed

    Searcy, Alan W; Beruto, Dario T; Barberis, Fabrizio

    2009-05-14

    In order to obtain consistency with the force balance theory of Young and Laplace, which quantitatively predicts the height of capillary rise from the contact angles of drops on solid surfaces, Gibbs made chemical potentials in interface functions of the integral interface free energies. We cite evidence that equilibrium chemical potentials in one-component systems are identical at interfaces to equilibrium chemical potentials in bulk phases. We evaluate two postulates. (1) Partial free energies of liquids at an interface with a solid are functions of the strength and range of attractive fields outside solid phase boundaries. (2) At equilibrium, the chemical potentials in all interfaces of a one-component liquid equal the chemical potential in its interior when the liquid is bonded to one or more immiscible solids. These postulates yield equations for partial equilibrium (PE) states of drops, films, and liquids. The PE equations yield the same prediction of the height of a meniscus from the contact angle of drops as does Young-Laplace theory and also the same dependence of the volume of capillary condensate on vapor pressure as does the Kelvin equation. But our measurements of the contact angles of water on glass and Teflon and between their close-spaced surfaces contradict the YL supposition that meniscus angles are the same as angles of drops on glass and Teflon surfaces and support the PE postulate that attraction by the external fields of solids, not meniscus curvature, is responsible for capillary rise. We use published data to illustrate the validity of the PE conclusion that divergence or convergence at the saturation pressure of a parent liquid depends on whether or not the attractive field of a solid surface imparts to the liquid more than twice the energy required to create two liquid-vapor interfaces. For divergent water films on quartz, the PE equation provides a quantitative fit to experimental data for films of any thickness greater than 1.5 nm. No

  19. Establishment of a total liquid ventilation system using saline-based oxygen micro/nano-bubble dispersions in rats.

    PubMed

    Kakiuchi, Kenta; Matsuda, Kenichi; Harii, Norikazu; Sou, Keitaro; Aoki, Junko; Takeoka, Shinji

    2015-09-01

    Micro/nano-bubbles are practical nanomaterials designed to increase the gas content in liquids. We attempted to use oxygen micro/nano-bubble dispersions as an oxygen-rich liquid as a means for total liquid ventilation. To determine the oxygen content in the bubble dispersion, a new method based on a spectrophotometric change between oxy- and deoxy-hemoglobin was established. The oxygen micro/nano-bubble dispersion was supplied to an experimental total ventilation liquid in anesthetic rats. Though the amount of dissolving oxygen was as low as 6 mg/L in physiological saline, the oxygen content in the oxygen micro/nano-bubble dispersion was increased to 45 mg/L. The positive correlation between the oxygen content and the life-saving time under liquid ventilation clearly indicates that the life-saving time is prolonged by increasing the oxygen content in the oxygen micro/nano-bubble dispersion. This is the first report indicating that the oxygen micro/nano-bubbles containing a sufficient amount of oxygen are useful in producing oxygen-rich liquid for the process of liquid ventilation.

  20. 46 CFR 177.600 - Ventilation of enclosed and partially enclosed spaces.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... be capable of being shut down from the pilot house. (c) An enclosed passenger or crew accommodation... electrical wiring installed in a metal protective enclosure may be installed within ventilation ducts, provided that the piping or the wiring does not interfere with the operation of fire dampers....

  1. 46 CFR 177.600 - Ventilation of enclosed and partially enclosed spaces.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... be capable of being shut down from the pilot house. (c) An enclosed passenger or crew accommodation... electrical wiring installed in a metal protective enclosure may be installed within ventilation ducts, provided that the piping or the wiring does not interfere with the operation of fire dampers....

  2. 46 CFR 177.600 - Ventilation of enclosed and partially enclosed spaces.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... be capable of being shut down from the pilot house. (c) An enclosed passenger or crew accommodation... electrical wiring installed in a metal protective enclosure may be installed within ventilation ducts, provided that the piping or the wiring does not interfere with the operation of fire dampers....

  3. 46 CFR 177.600 - Ventilation of enclosed and partially enclosed spaces.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... be capable of being shut down from the pilot house. (c) An enclosed passenger or crew accommodation... electrical wiring installed in a metal protective enclosure may be installed within ventilation ducts, provided that the piping or the wiring does not interfere with the operation of fire dampers....

  4. Effect of ultra-fast mild hypothermia using total liquid ventilation on hemodynamics and respiratory mechanics.

    PubMed

    Sage, Michaël; Nadeau, Mathieu; Kohlhauer, Matthias; Praud, Jean-Paul; Tissier, Renaud; Robert, Raymond; Walti, Hervé; Micheau, Philippe

    2016-08-01

    Ultra-fast cooling for mild therapeutic hypothermia (MTH) has several potential applications, including prevention of post-cardiac arrest syndrome. Ultra-fast MTH by total liquid ventilation (TLV) entails the sudden filling of the lungs with a cold perfluorocarbon liquid and its subsequent use to perform TLV. The present physiological study was aimed at assessing whether pulmonary and systemic hemodynamics as well as lung mechanics are significantly altered during this procedure. Pulmonary and systemic arterial pressures, cardiac output as well as airway resistance and respiratory system compliance were measured during ultra-fast MTH by TLV followed by rewarming and normothermia in six healthy juvenile lambs. Results show that none of the studied variables were altered upon varying the perfluorocarbon temperature from 12 to 41 °C. It is concluded that ultra-fast MTH by TLV does not have any deleterious effect on hemodynamics or lung mechanics in healthy juvenile lambs.

  5. Hydroelastic vibration analysis of partially liquid-filled shells using a series representation of the liquid

    NASA Technical Reports Server (NTRS)

    Housner, J. M.; Herr, R. W.; Sewall, J. L.

    1980-01-01

    A series representation of the oscillatory behavior of incompressible nonviscous liquids contained in partially filled elastic tanks is presented. Each term is selected on the basis of hydroelastic vibrations in circular cylindrical tanks. Using a complementary energy principle, the superposition of terms is made to approximately satisfy the liquid-tank interface compatibility. This analysis is applied to the gravity sloshing and hydroelastic vibrations of liquids in hemispherical tanks and in a typical elastic aerospace propellant tank. With only a few series terms retained, the results correlate very well with existing analytical results, NASTRAN-generated analytical results, and experimental test results. Hence, although each term is based on a cylindrical tank geometry, the superposition can be successfully applied to noncylindrical tanks.

  6. Mechanisms used to restore ventilation after partial upper airway collapse during sleep in humans.

    PubMed

    Jordan, Amy S; Wellman, Andrew; Heinzer, Raphael C; Lo, Yu-Lun; Schory, Karen; Dover, Louise; Gautam, Shiva; Malhotra, Atul; White, David P

    2007-10-01

    Most patients with obstructive sleep apnoea (OSA) can restore airflow after an obstructive respiratory event without arousal at least some of the time. The mechanisms that enable this ventilatory recovery are unclear but probably include increased upper airway dilator muscle activity and/or changes in respiratory timing. The aims of this study were to compare the ability to recover ventilation and the mechanisms of compensation following a sudden reduction of continuous positive airway pressure (CPAP) in subjects with and without OSA. Ten obese patients with OSA (mean (SD) apnoea-hypopnoea index 62.6 (12.4) events/h) and 15 healthy non-obese non-snorers were instrumented with intramuscular genioglossus electrodes and a mask/pneumotachograph which was connected to a modified CPAP device that could deliver either continuous positive or negative pressure. During stable non-rapid eye movement sleep the CPAP was repeatedly reduced 2-10 cm H2O below the level required to eliminate flow limitation and was held at this level for 5 min or until arousal from sleep occurred. During reduced CPAP the increases in genioglossus activity (311.5 (49.4)% of baseline in subjects with OSA and 315.4 (76.2)% of baseline in non-snorers, p = 0.9) and duty cycle (123.8 (3.9)% of baseline in subjects with OSA and 118.2 (2.8)% of baseline in non-snorers, p = 0.4) were similar in both groups, yet patients with OSA could restore ventilation without cortical arousal less often than non-snorers (54.1% vs 65.7% of pressure drops, p = 0.04). When ventilatory recovery did not occur, genioglossus muscle and respiratory timing changes still occurred but these did not yield adequate pharyngeal patency/ventilation. Compensatory mechanisms (increased genioglossus muscle activity and/or duty cycle) often restore ventilation during sleep but may be less effective in obese patients with OSA than in non-snorers.

  7. Optimal control of inspired perfluorocarbon temperature for induction of hypothermia by total liquid ventilation in juvenile lamb model.

    PubMed

    Nadeau, Mathieu; Sage, Michael; Praud, Jean-Paul; Tissier, Renaud; Walti, Herve; Micheau, Philippe; Nadeau, Mathieu; Sage, Michael; Praud, Jean-Paul; Tissier, Renaud; Walti, Herve; Micheau, Philippe; Sage, Michael; Micheau, Philippe; Praud, Jean-Paul; Nadeau, Mathieu; Walti, Herve; Tissier, Renaud

    2016-08-01

    Mild hypothermia is well known for its therapeutic value in cardio- and neuroprotection. Many recent experimental studies have shown that the swiftness of the cooling offered by total liquid ventilation (TLV) holds great promise in achieving maximal therapeutic effect. TLV is an emerging ventilation technique in which the lungs are filled with breathable liquids, namely perfluorocarbons (PFCs). A liquid ventilator ensures subject ventilation by periodically renewing a volume of oxygenated, CO2-free and temperature-controlled breathable PFC. The substantial difference between breathing air and liquid is related to the fact that PFCs have over 500 times the volumetric thermal capacity of air 100% relative humidity. The PFC-filled lungs thus turn into an efficient heat exchanger with pulmonary circulation. The objective of the present study was to compute a posteriori the optimal inspired PFC temperature for ultrafast induction of mild hypothermia by TLV in a juvenile lamb experimentation using direct optimal control. The continuous time model and the discretized cycle-by-cycle model are presented. The control objectives of the direct optimal control are also presented and the results are compared with experimental data in order to validate the improved control performances. The computed direct optimal control showed that the inspired PFC temperature command can be improved to avoid temperature undershoots without altering the cooling performances.

  8. A morphologic study of long-term retention of fluorocarbon after liquid ventilation.

    PubMed

    Hood, C I; Modell, J H

    2000-11-01

    To determine how long perfluorinated hydrocarbons remain in the lung after they are used for lung ventilation in dogs, and to determine if residual perfluorinated hydrocarbons cause structural alteration or an inflammatory reaction of the lung. Adult dogs were anesthetized and received ventilation with oxygenated perfluorinated hydrocarbon liquid. Morphologic studies of tissue from the lungs of these dogs were performed at intervals of a few minutes to 10 years after reconversion to breathing gas. University College of Medicine. Adult mongrel and beagle dogs. Anesthetized adult dogs breathed oxygenated liquid fluorocarbons for 1 h and then were reconverted to breathing air. Three fluorocarbons, FX-80 (C(8)F(16)O; 3M Company; St. Paul, MN), Caroxin-D (C(10)F(22)O(2); P-1D; Allied Chemical Company; Morristown, NJ), and Caroxin-F (C(9)F(20)O; P-12F; Allied Chemical Company), were used. Morphologic studies of the lungs of these animals were performed immediately after restoration of air breathing and at intervals for up to 10 years. Not all animals were studied at each time interval. A transient, acute inflammatory reaction was followed by a massive influx of macrophages, which were at first intra-alveolar and later interstitial, especially around vessels and bronchioles. Fluorocarbons remained in the lung in diminishing amounts for at least 5 years, as evidenced by persistent vacuolated macrophages in the alveoli, interstitium, and hilar lymph nodes; fluorocarbon was also detected in these tissues by chemical assays. In no case was there fibrosis or any other structural alteration associated with the residual fluorocarbon, which suggests that it was inert. At 10 years, no evidence of residual fluorocarbon was seen morphologically.

  9. Comparison of artificial neural network (ANN) and partial least squares (PLS) regression models for predicting respiratory ventilation: an exploratory study.

    PubMed

    Lin, Ming-I Brandon; Groves, William A; Freivalds, Andris; Lee, Eun Gyung; Harper, Martin

    2012-05-01

    The objective of this study was to assess the potential for using artificial neural networks (ANN) to predict inspired minute ventilation (V(I)) during exercise activities. Six physiological/kinematic measurements obtained from a portable ambulatory monitoring system, along with individual's anthropometric and demographic characteristics, were employed as input variables to develop and optimize the ANN configuration with respect to reference values simultaneously measured using a pneumotachograph (PT). The generalization ability of the resulting two-hidden-layer ANN model was compared with a linear predictive model developed through partial least squares (PLS) regression, as well as other V(I) predictive models proposed in the literature. Using an independent dataset recorded from nine 80-min step tests, the results showed that the ANN-estimated V(I) was highly correlated (R(2) = 0.88) with V(I) measured by the PT, with a mean difference of approximately 0.9%. In contrast, the PLS and other regression-based models resulted in larger average errors ranging from 7 to 34%. In addition, the ANN model yielded estimates of cumulative total volume that were on average within 1% of reference PT measurements. Compared with established statistical methods, the proposed ANN model demonstrates the potential to provide improved prediction of respiratory ventilation in workplace applications for which the use of traditional laboratory-based instruments is not feasible. Further research should be conducted to investigate the performance of ANNs for different types of physical activity in larger and more varied worker populations.

  10. Nucleation type instabilities in partially wetting nanoscale nematic liquid films

    NASA Astrophysics Data System (ADS)

    Lam, Michael; Cummings, Linda; Kondic, Lou

    2016-11-01

    Nucleation type instabilities are studied in nematic liquid crystal (NLC) films with thicknesses less than a micrometer. Within the framework of the long wave approximation, a 4th order nonlinear partial differential equation is proposed for the free surface height. Unlike simple fluids, NLC molecules have a dipole moment which induces an elastic response due to deformation in the bulk of the fluid. The model includes the balance between the bulk elasticity energy and the anchoring (boundary) energy at the substrate and free surface, and van der Waals' intermolecular forces, by means of a structural disjoining pressure. In this presentation, we focus on two-dimensional flow and present simulation results for a flat film with a localized perturbation. We are interested in the morphology of the dewetted film as a function of the initial film thickness. We will show that there exists a range of film thicknesses within the linearly unstable flat film regime where stability analysis does not explain the morphology of the dewetted film. Marginal stability criterion (MSC) is used to derive an analytical expression for the velocity at which a perturbation propagates into the unstable flat film. Finally, we discuss the degree to which MSC can be used to explain the observed morphology.

  11. Wissler Simulations of a Liquid Cooled and Ventilation Garment (LCVG) for Extravehicular Activity (EVA)

    NASA Technical Reports Server (NTRS)

    Kesterson, Matthew; Bue, Grant; Trevino, Luis

    2006-01-01

    In order to provide effective cooling for astronauts during extravehicular activities (EVAs), a liquid cooling and ventilation garment (LCVG) is used to remove heat by a series off tubes through which cooling water is circulated. To better predict the effectiveness of the LCG and determine possible modifications to improve performance, computer simulations dealing with the interaction of the cooling garment with the human body have been run using the Wissler Human Model. Simulations have been conducted to predict the heat removal rate for various liquid cooled garment configurations. The current LCVG uses 48 cooling tubes woven into a fabric with cooling water flowing through the tubes. The purpose of the current project is to decrease the overall weight of the LCVG system. In order to achieve this weight reduction, advances in the garment heat removal rates need to be obtained. Currently, increasing the fabric s thermal conductivity along with also examining an increase in the cooling tube conductivity to more efficiently remove the excess heat generated during EVA is being simulated. Initial trials varied cooling water temperature, water flow rate, garment conductivity, tube conductivity, and total number of cooling tubes in the LCVG. Results indicate that the total number of cooling tubes could be reduced to 22 and still achieve the desired heat removal rate of 361 W. Further improvements are being made to the garment network used in the model to account for temperature gradients associated with the spacing of the cooling tubes over the surface of the garment

  12. Using Dalton's Law of Partial Pressures to Determine the Vapor Pressure of a Volatile Liquid

    ERIC Educational Resources Information Center

    Hilgeman, Fred R.; Bertrand, Gary; Wilson, Brent

    2007-01-01

    This experiment, designed for a general chemistry laboratory, illustrates the use of Dalton's law of partial pressures to determine the vapor pressure of a volatile liquid. A predetermined volume of air is injected into a calibrated tube filled with a liquid whose vapor pressure is to be measured. The volume of the liquid displaced is greater than…

  13. Using Dalton's Law of Partial Pressures to Determine the Vapor Pressure of a Volatile Liquid

    ERIC Educational Resources Information Center

    Hilgeman, Fred R.; Bertrand, Gary; Wilson, Brent

    2007-01-01

    This experiment, designed for a general chemistry laboratory, illustrates the use of Dalton's law of partial pressures to determine the vapor pressure of a volatile liquid. A predetermined volume of air is injected into a calibrated tube filled with a liquid whose vapor pressure is to be measured. The volume of the liquid displaced is greater than…

  14. Dynamic and quasi-static lung mechanics system for gas-assisted and liquid-assisted ventilation.

    PubMed

    Alvarez, Francisco J; Gastiasoro, Elena; Rey-Santano, M Carmen; Gomez-Solaetxe, Miguel A; Publicover, Nelson G; Larrabe, Juan L

    2009-07-01

    Our aim was to develop a computerized system for real-time monitoring of lung mechanics measurements during both gas and liquid ventilation. System accuracy was demonstrated by calculating regression and percent error of the following parameters compared to standard device: airway pressure difference (Delta P(aw)), respiratory frequency (f(R) ), tidal volume (V(T)), minute ventilation (V'(E)), inspiratory and expiratory maximum flows (V'(ins,max), V'(exp,max)), dynamic lung compliance (C(L,dyn) ), resistance of the respiratory system calculated by method of Mead-Whittenberger (R(rs,MW)) and by equivalence to electrical circuits (R(rs,ele)), work of breathing (W(OB)), and overdistension. Outcome measures were evaluated as function of gas exchange, cardiovascular parameters, and lung mechanics including mean airway pressure (mP(aw)). Delata P(aw), V(T), V'(ins,max), V'(exp,max), and V'(E) measurements had correlation coefficients r = 1.00, and %error < 0.5%. f(R), C(L,dyn), R(rs,MW), R(rs,ele), and W(OB) showed r > or = 0.98 and %error < 5%. Overdistension had r = 0.87 and %error < 15%. Also, resistance was accurately calculated by a new algorithm. The system was tested in rats in which lung lavage was used to induce acute respiratory failure. After lavage, both gas- and liquid-ventilated groups had increased mP(aw) and W(OB), with decreased V(T), V'(E), C(L,dyn), R(rs,MW), and R(rs,ele) compared to controls. After 1-h ventilation, both injured group had decreased V(T), V'(E) , and C(L,dyn), with increased mP(aw), R(rs,MW), R(rs,ele), and W(OB) . In lung-injured animals, liquid ventilation restored gas exchange, and cardiovascular and lung functions. Our lung mechanics system was able to closely monitor pulmonary function, including during transitions between gas and liquid phases.

  15. A comparison of three liquid-ventilation cooling garments during treadmill exercise

    NASA Technical Reports Server (NTRS)

    Webbon, B.; Miller, L.; Williams, B.; Montgomery, L.

    1981-01-01

    A comparative study was made of the heat transfer performance and physiological effects of three different cooling garments used under sealed garments (simulating space suits) on five male subjects, during treadmill exercise. The mean exercise metabolic rate while walking at 0.9 m/s (2 mph) was 464 plus or minus 33 W. An equilibrium condition was never reached during the uncooled suited control runs and the subjects lost approximately two percent of body weight during the exercises. The mean weight loss with an Apollo-type garment was 0.35 plus or minus 0.10 kg, and 0.26 plus or minus 0.11 kg with the full-body cooling patch garment (garment 2). With the partial-coverage cooling patch (garment 3), the weight loss was 0.52 plus or minus 0.12 kg. The data showed an increase in the leg blood flow when the working muscles were not cooled by liquid flow (garment 3), and the arm blood flow remained unchanged with and without liquid cooling to the arms.

  16. A comparison of three liquid-ventilation cooling garments during treadmill exercise

    NASA Technical Reports Server (NTRS)

    Webbon, B.; Miller, L.; Williams, B.; Montgomery, L.

    1981-01-01

    A comparative study was made of the heat transfer performance and physiological effects of three different cooling garments used under sealed garments (simulating space suits) on five male subjects, during treadmill exercise. The mean exercise metabolic rate while walking at 0.9 m/s (2 mph) was 464 plus or minus 33 W. An equilibrium condition was never reached during the uncooled suited control runs and the subjects lost approximately two percent of body weight during the exercises. The mean weight loss with an Apollo-type garment was 0.35 plus or minus 0.10 kg, and 0.26 plus or minus 0.11 kg with the full-body cooling patch garment (garment 2). With the partial-coverage cooling patch (garment 3), the weight loss was 0.52 plus or minus 0.12 kg. The data showed an increase in the leg blood flow when the working muscles were not cooled by liquid flow (garment 3), and the arm blood flow remained unchanged with and without liquid cooling to the arms.

  17. Transport processes in partially saturate concrete: Testing and liquid properties

    NASA Astrophysics Data System (ADS)

    Villani, Chiara

    The measurement of transport properties of concrete is considered by many to have the potential to serve as a performance criterion that can be related to concrete durability. However, the sensitivity of transport tests to several parameters combined with the low permeability of concrete complicates the testing. Gas permeability and diffusivity test methods are attractive due to the ease of testing, their non-destructive nature and their potential to correlate to in-field carbonation of reinforced concrete structures. This work was aimed at investigating the potential of existing gas transport tests as a way to reliably quantify transport properties in concrete. In this study gas permeability and diffusivity test methods were analyzed comparing their performance in terms of repeatability and variability. The influence of several parameters was investigated such as moisture content, mixture proportions and gas flow. A closer look to the influence of pressure revealed an anomalous trend of permeability with respect to pressure. An alternative calculation is proposed in an effort to move towards the determination of intrinsic material properties that can serve as an input for service life prediction models. The impact of deicing salts exposure was also analyzed with respect to their alteration of the degree of saturation as this may affect gas transport in cementitious materials. Limited information were previously available on liquid properties over a wide range of concentrations. To overcome this limitation, this study quantified surface tension, viscosity in presence of deicing salts in a broad concentration range and at different temperatures. Existing models were applied to predict the change of fluid properties during drying. Vapor desorption isotherms were obtained to investigate the influence of deicing salts presence on the non-linear moisture diffusion coefficient. Semi-empirical models were used to quantify the initiation and the rate of drying using liquid

  18. Partial liquidation rules provide stockholder tax saving opportunities in oil and gas divestitures

    SciTech Connect

    Blatz, R.E. Jr.

    1984-09-01

    Oil and gas companies are looking at divestiture as a result of the current oil glut. A summary of the current rules governing partial liquidations focuses on stockholder gain or loss calculations in qualified partial liquidations. These calculations are not routine, and can provide a tax-saving opportunity for the stockholders. Revenue Ruling 81-3 and 77-245 mandate a specific mechanical computation in determining the number of shares considered surrendered, but the stockholder has some latitude in planning his gain or loss by selecting the specific shares to be surrendered. 24 references, 3 tables.

  19. Simultaneous heat and mass transfer from a two-dimensional, partially liquid-covered surface

    SciTech Connect

    Tao, Y.X.; Kaviany, M. )

    1991-11-01

    Simultaneous heat and mass transfer from partially liquid-covered surfaces is examined experimentally using a surface made of cylinders with the voids filled with liquid. The steady-state evaporation rate, surface temperature of the liquid and exposed solid, and location of meniscus are measured for various ambient air velocities and temperatures. Using these, the authors examine the effect of the extent to which the liquid covers the surface on the evaporation mass transfer rate resulting from the convective heat transfer from the ambient gas to this surface. The results show strong Bond and Reynolds number effects. For small Bond and Reynolds numbers, the presence of dry (exposed solid) surface does not influence the mass transfer rate. As the Bond or Reynolds number increases, a critical liquid coverage is found below which the mass transfer begins to decrease. Heat transfer from the exposed solid to the liquid is also examined using the measured surface temperature, a conduction model, and an estimate of the liquid and solid surface areas (using a static formation for the liquid meniscus). The results show that at the liquid surface an analogy between heat and mass transfer does not exist.

  20. Lattice Boltzmann simulations of incompressible liquid-gas systems on partial wetting surfaces.

    PubMed

    Shih, Ching-Hsiang; Wu, Cheng-Long; Chang, Li-Chen; Lin, Chao-An

    2011-06-28

    A three-dimensional Lattice Boltzmann two-phase model capable of dealing with large liquid and gas density ratios and with a partial wetting surface is introduced. This is based on a high density ratio model combined with a partial wetting boundary method. The predicted three-dimensional droplets at different partial wetting conditions at equilibrium are in good agreement with analytical solutions. Despite the large density ratio, the spurious velocity around the interface is not substantial, and is rather insensitive to the examined liquid and gas density and viscosity ratios. The influence of the gravitational force on the droplet shape is also examined through the variations of the Bond number, where the droplet shape migrates from spherical to flattened interface in tandem with the increase of the Bond number. The predicted interfaces under constant Bond number are also validated against measurements with good agreements.

  1. Highly pressurized partially miscible liquid-liquid flow in a micro-T-junction. I. Experimental observations

    NASA Astrophysics Data System (ADS)

    Qin, Ning; Wen, John Z.; Ren, Carolyn L.

    2017-04-01

    This is the first part of a two-part study on a partially miscible liquid-liquid flow (liquid carbon dioxide and deionized water) which is highly pressurized and confined in a microfluidic T-junction. Our main focuses are to understand the flow regimes as a result of varying flow conditions and investigate the characteristics of drop flow distinct from coflow, with a capillary number, C ac , that is calculated based on the continuous liquid, ranging from 10-3 to 10-2 (10-4 for coflow). Here in part I, we present our experimental observation of drop formation cycle by tracking drop length, spacing, frequency, and after-generation speed using high-speed video and image analysis. The drop flow is chronologically composed of a stagnating and filling stage, an elongating and squeezing stage, and a truncating stage. The common "necking" time during the elongating and squeezing stage (with C ac˜10-3 ) for the truncation of the dispersed liquid stream is extended, and the truncation point is subsequently shifted downstream from the T-junction corner. This temporal postponement effect modifies the scaling function reported in the literature for droplet formation with two immiscible fluids. Our experimental measurements also demonstrate the drop speed immediately following their generations can be approximated by the mean velocity from averaging the total flow rate over the channel cross section. Further justifications of the quantitative analysis by considering the mass transfer at the interface of the two partially miscible fluids are provided in part II.

  2. Ventilation and ventilators.

    PubMed

    Hayes, B

    1982-01-01

    The history of ventilation is reviewed briefly and recent developments in techniques of ventilation are discussed. Operating features of ventilators have changed in the past few years, partly as the result of clinical progress; yet, technology appears to have outstripped the clinician's ability to harness it most effectively. Clinical discipline and training of medical staff in the use of ventilators could be improved. The future is promising if clinician and designer can work together closely. Ergonomics of ventilators and their controls and the provision of alarms need special attention. Microprocessors are likely to feature prominently in the next generation of designs.

  3. Plasma Jet Interactions with Liquids in Partial Fulfillment of an NRL Karles Fellowship

    DTIC Science & Technology

    2015-11-30

    deposition), modify (e.g., chemical functionalization), and etch (in Si technology) materials. In low- pressure non-equilibrium discharge plasmas ...Naval Research Laboratory Washington, DC 20375-5320 NRL/MR/6750--15-9650 Plasma Jet Interactions with Liquids in Partial Fulfillment of an NRL... Plasma Physics Division i REPORT DOCUMENTATION PAGE Form ApprovedOMB No. 0704-0188 3. DATES COVERED (From - To) Standard Form 298 (Rev. 8-98

  4. Plasma Jet Interactions with Liquids in Partial Fulfillment of an NRL Karle’s Fellowship

    DTIC Science & Technology

    2015-11-30

    deposition), modify (e.g., chemical functionalization), and etch (in Si technology) materials. In low- pressure non-equilibrium discharge plasmas ...Naval Research Laboratory Washington, DC 20375-5320 NRL/MR/6750--15-9650 Plasma Jet Interactions with Liquids in Partial Fulfillment of an NRL... Plasma Physics Division i REPORT DOCUMENTATION PAGE Form ApprovedOMB No. 0704-0188 3. DATES COVERED (From - To) Standard Form 298 (Rev. 8-98

  5. Bifurcation analysis of the behavior of partially wetting liquids on a rotating cylinder

    NASA Astrophysics Data System (ADS)

    Lin, Te-Sheng; Rogers, Steven; Tseluiko, Dmitri; Thiele, Uwe

    2016-08-01

    We discuss the behavior of partially wetting liquids on a rotating cylinder using a model that takes into account the effects of gravity, viscosity, rotation, surface tension, and wettability. Such a system can be considered as a prototype for many other systems where the interplay of spatial heterogeneity and a lateral driving force in the proximity of a first- or second-order phase transition results in intricate behavior. So does a partially wetting drop on a rotating cylinder undergo a depinning transition as the rotation speed is increased, whereas for ideally wetting liquids, the behavior only changes quantitatively. We analyze the bifurcations that occur when the rotation speed is increased for several values of the equilibrium contact angle of the partially wetting liquids. This allows us to discuss how the entire bifurcation structure and the flow behavior it encodes change with changing wettability. We employ various numerical continuation techniques that allow us to track stable/unstable steady and time-periodic film and drop thickness profiles. We support our findings by time-dependent numerical simulations and asymptotic analyses of steady and time-periodic profiles for large rotation numbers.

  6. The stability of motion of satellites with cavities partially filled with liquid

    NASA Technical Reports Server (NTRS)

    Nayfeh, A. H.; Meirovitch, L.

    1975-01-01

    The stability and time dependent motion of a spinning satellite, simulated by a rigid body with a cavity partially filled with liquid is examined. The problem formulation, consisting of the boundary-value problem for the liquid and moment equations for the entire system is presented. Because of large Reynold's numbers involved, viscosity effects are negligible everywhere except for a thin boundary layer near the wetted surface. Using a boundary-layer analysis, the effect of the boundary layer is replaced by modified boundary conditions for the liquid. The solution of the differential equations for the inviscid problem is solved in closed form. A semi-analytical numerical solution of the inviscid equations subject to the viscous boundary condition has proved unsucessful.

  7. Effects of Oxygen Partial Pressure on the Surface Tension of Liquid Nickel

    NASA Technical Reports Server (NTRS)

    SanSoucie, Michael P.; Rogers, Jan R.; Gowda, Vijaya Kumar Malahalli Shankare; Rodriguez, Justin; Matson, Douglas M.

    2015-01-01

    The NASA Marshall Space Flight Center's electrostatic levitation (ESL) laboratory has been recently upgraded with an oxygen partial pressure controller. This system allows the oxygen partial pressure within the vacuum chamber to be measured and controlled, theoretically in the range from 10-36 to 100 bar. The oxygen control system installed in the ESL laboratory's main chamber consists of an oxygen sensor, oxygen pump, and a control unit. The sensor is a potentiometric device that determines the difference in oxygen activity in two gas compartments (inside the chamber and the air outside of the chamber) separated by an electrolyte, which is yttria-stabilized zirconia. The pump utilizes coulometric titration to either add or remove oxygen. The system is controlled by a desktop control unit, which can also be accessed via a computer. The controller performs temperature control for the sensor and pump, PID-based current loop, and a control algorithm. Oxygen partial pressure has been shown to play a significant role in the surface tension of liquid metals. Oxide films or dissolved oxygen may lead to significant changes in surface tension. The effects of oxygen partial pressure on the surface tension of undercooled liquid nickel will be analyzed, and the results will be presented. The surface tension will be measured at several different oxygen partial pressures while the sample is undercooled. Surface tension will be measured using the oscillating drop method. While undercooled, each sample will be oscillated several times consecutively to investigate how the surface tension behaves with time while at a particular oxygen partial pressure.

  8. Experimental derivation of nepheline syenite and phonolite liquids by partial melting of upper mantle peridotites

    NASA Astrophysics Data System (ADS)

    Laporte, Didier; Lambart, Sarah; Schiano, Pierre; Ottolini, Luisa

    2014-10-01

    Piston-cylinder experiments were performed to characterize the composition of liquids formed at very low degrees of melting of two fertile lherzolite compositions with 430 ppm and 910 ppm K2O at 1 and 1.3 GPa. We used the microdike technique (Laporte et al., 2004) to extract the liquid phase from the partially molten peridotite, allowing us to analyze liquid compositions at degrees of melting F down to 0.9%. At 1.3 GPa, the liquid is in equilibrium with olivine + orthopyroxene + clinopyroxene + spinel in all the experiments; at 1 GPa, plagioclase is present in addition to these four mineral phases up to about 5% of melting (T≈1240 °C). Important variations of liquid compositions are observed with decreasing temperature, including strong increases in SiO2, Na2O, K2O, and Al2O3 concentrations, and decreases in MgO, FeO, and CaO concentrations. The most extreme liquid compositions are phonolites with 57% SiO2, 20-22% Al2O3, Na2O + K2O up to 14%, and concentrations of MgO, FeO, and CaO as low as 2-3%. Reversal experiments confirm that low-degree melts of a fertile lherzolite have phonolitic compositions, and pMELTS calculations show that the amount of phonolite liquid generated at 1.2 GPa increases from 0.3% in a source with 100 ppm K2O to 3% in a source with 2000 ppm K2O. The enrichment in silica and alkalis with decreasing melt fraction is coupled with an increase of the degree of melt polymerization, which has important consequences for the partitioning of minor and trace elements. Thus Ti4+ in our experiments and, by analogy with Ti4+, other highly charged cations, and rare earth elements become less incompatible near the peridotite solidus. Our study brings a strong support to the hypothesis that phonolitic lavas or their plutonic equivalents (nepheline syenites) may be produced directly by partial melting of upper mantle rock-types at moderate pressures (1-1.5 GPa), especially where large domains of the subcontinental lithospheric mantle has been enriched in

  9. Experimental Investigation of Ventilation of a Surface Piercing Hydrofoil

    NASA Astrophysics Data System (ADS)

    Harwood, Casey; Miguel Montero, Francisco; Young, Yin Lu; Ceccio, Steven

    2013-11-01

    Bodies that pierce a liquid free-surface are prone to entrainment of atmospheric and/or vaporous gases. This process, called ventilation, can occur suddenly and violently, drastically altering hydrodynamic response. Experiments have been conducted at the free-surface towing-tank in the University of Michigan Marine Hydrodynamics Laboratory to investigate fully attached, partially ventilated, and fully ventilated flows around a canonical surface-piercing hydrofoil. The objectives of the work are: (i) to gain a broad and improved understanding of the physics of ventilation, (ii) to classify the physical mechanisms by which ventilation inception and washout may occur and quantify the conditions required for each mechanism and (iii) to quantify the effects of ventilation on global hydrodynamic responses, including the six force and moment components. Experimental data and high-speed video will be used to illustrate the impact of ventilation on hydrodynamic loads, pressures, and flow structures. The completion of this study is expected to contribute significantly toward a comprehensive understanding of ventilation physics, and toward an improved ability to design safe and controllable ventilated lifting surfaces for use in propulsion, energy harvesting, and turbomachinery. Supported by: The Office of Naval Research (ONR) (Grant No. N00014-09-1-1204); the National Research Foundation of Korea (NRF) (GCRC-SOP Grant No. 2012-0004783); the National Science Foundation Graduate Student Research Fellowship (Grant No. DGE 1256260).

  10. Internal resonances and dynamic responses in equivalent mechanical model of partially liquid-filled vessel

    NASA Astrophysics Data System (ADS)

    Farid, M.; Gendelman, O. V.

    2016-09-01

    The paper treats dynamical responses in an equivalent mechanical model for oscillations of a liquid in partially filled vessel under horizontal harmonic ground excitation. Such excitation may lead to hydraulic impacts. The liquid sloshing mass is modeled by equivalent pendulum, which can impact the vessel walls. Parameters of the equivalent pendulum for well-explored case of cylindrical vessels are used. The hydraulic impacts are modeled by high-power potential function. Conditions for internal resonances are formulated. A non-resonant behavior and dynamic response related to 3:1 internal resonance are explored. When the excitation amplitude exceeds certain critical value, the system exhibits multiple steady state solutions. Quasi-periodic solutions appear in relatively narrow range of parameters. Numerical continuation links between resonant regimes found asymptotically for small excitation amplitude, and high-amplitude responses with intensive impacts.

  11. Communication: Probing the existence of partially arrested states in ionic liquids.

    PubMed

    Ramírez-González, Pedro E; Sanchéz-Díaz, Luis E; Medina-Noyola, Magdaleno; Wang, Yanting

    2016-11-21

    The recent predictions of the self-consistent generalized Langevin equation theory, describing the existence of unusual partially arrested states in the context of ionic liquids, were probed using all-atom molecular dynamics simulations of a room-temperature ionic liquid. We have found a slower diffusion of the smaller anions compared with the large cations for a wide range of temperatures. The arrest mechanism consists on the formation of a strongly repulsive glass by the anions, stabilized by the long range electrostatic potential. The diffusion of the less repulsive cations occurs through the holes left by the small particles. All of our observations in the simulated system coincide with the theoretical picture.

  12. Administration of hydrogen sulfide via extracorporeal membrane lung ventilation in sheep with partial cardiopulmonary bypass perfusion: a proof of concept study on metabolic and vasomotor effects

    PubMed Central

    2011-01-01

    Introduction Although inhalation of 80 parts per million (ppm) of hydrogen sulfide (H2S) reduces metabolism in mice, doses higher than 200 ppm of H2S were required to depress metabolism in rats. We therefore hypothesized that higher concentrations of H2S are required to reduce metabolism in larger mammals and humans. To avoid the potential pulmonary toxicity of H2S inhalation at high concentrations, we investigated whether administering H2S via ventilation of an extracorporeal membrane lung (ECML) would provide means to manipulate the metabolic rate in sheep. Methods A partial venoarterial cardiopulmonary bypass was established in anesthetized, ventilated (fraction of inspired oxygen = 0.5) sheep. The ECML was alternately ventilated with air or air containing 100, 200, or 300 ppm H2S for intervals of 1 hour. Metabolic rate was estimated on the basis of total CO2 production (V˙CO2) and O2 consumption (V˙O2). Continuous hemodynamic monitoring was performed via indwelling femoral and pulmonary artery catheters. Results V˙CO2, V˙O2, and cardiac output ranged within normal physiological limits when the ECML was ventilated with air and did not change after administration of up to 300 ppm H2S. Administration of 100, 200 and 300 ppm H2S increased pulmonary vascular resistance by 46, 52 and 141 dyn·s/cm5, respectively (all P ≤ 0.05 for air vs. 100, 200 and 300 ppm H2S, respectively), and mean pulmonary artery pressure by 4 mmHg (P ≤ 0.05), 3 mmHg (n.s.) and 11 mmHg (P ≤ 0.05), respectively, without changing pulmonary capillary wedge pressure or cardiac output. Exposure to 300 ppm H2S decreased systemic vascular resistance from 1,561 ± 553 to 870 ± 138 dyn·s/cm5 (P ≤ 0.05) and mean arterial pressure from 121 ± 15 mmHg to 66 ± 11 mmHg (P ≤ 0.05). In addition, exposure to 300 ppm H2S impaired arterial oxygenation (PaO2 114 ± 36 mmHg with air vs. 83 ± 23 mmHg with H2S; P ≤ 0.05). Conclusions Administration of up to 300 ppm H2S via ventilation of an

  13. Highly pressurized partially miscible liquid-liquid flow in a micro-T-junction. II. Theoretical justifications and modeling

    NASA Astrophysics Data System (ADS)

    Qin, Ning; Wen, John Z.; Ren, Carolyn L.

    2017-04-01

    This is the second part of a two-part study on a partially miscible liquid-liquid flow (carbon dioxide and deionized water) that is highly pressurized and confined in a microfluidic T-junction. In the first part of this study, we reported experimental observations of the development of flow regimes under various flow conditions and the quantitative characteristics of the drop flow including the drop length, after-generation drop speed, and periodic spacing development between an emerging drop and the newly produced one. Here in part II we provide theoretical justifications to our quantitative studies on the drop flow by considering (1) C O2 hydration at the interface with water, (2) the diffusion-controlled dissolution of C O2 molecules in water, and (3) the diffusion distance of the dissolved C O2 molecules. Our analyses show that (1) the C O2 hydration at the interface is overall negligible, (2) a saturation scenario of the dissolved C O2 molecules in the vicinity of the interface will not be reached within the contact time between the two fluids, and (3) molecular diffusion does play a role in transferring the dissolved molecules, but the diffusion distance is very limited compared with the channel geometry. In addition, mathematical models for the drop length and the drop spacing are developed based on the observations in part I, and their predictions are compared to our experimental results.

  14. Dielectric relaxation process of a partially unwound helical structure in ferroelectric liquid crystals.

    PubMed

    Choudhary, Amit; Bawa, Ambika; Rajesh; Singh, Surinder P; Biradar, Ashok M

    2017-06-01

    The fluctuations of unwound helical structure have been observed in deformed helix ferroelectric liquid crystal (DHFLC) and conventional FLC sample cells. The helix is partially unwound by strong anchoring on the substrates. In such sample cells, the helical decarlization lines are not observed in the texture under crossed polarized microscope. The dielectric spectroscopy is employed to observe the behavior of dielectric relaxation processes in these sample cells. A dielectric relaxation process is observed at a lower frequency than the Goldstone mode processes in DHFLC and FLC, which we call partially unwound helical mode (p-UHM). However, the p-UHM process is not observed in the sample cell in which the helical lines appear. The application of various amplitudes of probing ac voltages on this mode has shown the higher frequency shift, i.e., the larger the amplitude of ac voltage, the higher is the relaxation frequency of p-UHM. At sufficient amplitude of applied probing ac voltage, the p-UHM merges with the Goldstone mode process and is difficult to detect. However, the Goldstone mode relaxation frequency is almost independent of the cell geometry and sample configuration. The electro-optical behavior of the p-UHM has also been confirmed by electro-optical technique. The dielectric relaxation of UHM at a frequency lower than the Goldstone mode is interpreted as the fluctuation of partially unwound helix.

  15. Dielectric relaxation process of a partially unwound helical structure in ferroelectric liquid crystals

    NASA Astrophysics Data System (ADS)

    Choudhary, Amit; Bawa, Ambika; Rajesh, Singh, Surinder P.; Biradar, Ashok M.

    2017-06-01

    The fluctuations of unwound helical structure have been observed in deformed helix ferroelectric liquid crystal (DHFLC) and conventional FLC sample cells. The helix is partially unwound by strong anchoring on the substrates. In such sample cells, the helical decarlization lines are not observed in the texture under crossed polarized microscope. The dielectric spectroscopy is employed to observe the behavior of dielectric relaxation processes in these sample cells. A dielectric relaxation process is observed at a lower frequency than the Goldstone mode processes in DHFLC and FLC, which we call partially unwound helical mode (p-UHM). However, the p-UHM process is not observed in the sample cell in which the helical lines appear. The application of various amplitudes of probing ac voltages on this mode has shown the higher frequency shift, i.e., the larger the amplitude of ac voltage, the higher is the relaxation frequency of p-UHM. At sufficient amplitude of applied probing ac voltage, the p-UHM merges with the Goldstone mode process and is difficult to detect. However, the Goldstone mode relaxation frequency is almost independent of the cell geometry and sample configuration. The electro-optical behavior of the p-UHM has also been confirmed by electro-optical technique. The dielectric relaxation of UHM at a frequency lower than the Goldstone mode is interpreted as the fluctuation of partially unwound helix.

  16. Eggs and milk: Spinning spheres partially immersed in a liquid bath

    NASA Astrophysics Data System (ADS)

    Langley, Kenneth R.; Maynes, Daniel; Truscott, Tadd T.

    2015-03-01

    When a hard-boiled egg spins through a pool of milk on the kitchen counter, the milk rises up the sides of the egg and droplets are ejected. This phenomenon occurs when any partially submerged object whose radius increases upward from the fluid surface (e.g., spheres, inverted cones, and rings) spins in a liquid bath. The fluid ejects from the surface near the maximum radius in one of three ejection modes: jets, sheets, or sheet breakup. Additionally, a surprisingly large flow rate is induced by the spinning object. In this study, we used spheres to determine the effects of experimental parameters on the induced flow rate. We characterized the modes of ejection and measured the sheet breakup distance using high-speed imaging. The basis of our closed form analytical model utilizes an integral momentum boundary layer analysis both beneath the free surface and in the thin film attached to the sphere. We present criteria defining the transitions between ejection modes and the radius where liquid sheets break up in the sheet ejection regime. Criteria defining the transitions between ejection modes and the radius where liquid sheets break up in the sheet ejection regime shows good agreement with experiments.

  17. Nonlinear seismic response of a partially-filled rectangular liquid tank with a submerged block

    NASA Astrophysics Data System (ADS)

    Nayak, Santosh Kumar; Biswal, Kishore Chandra

    2016-04-01

    The seismic response of partially-filled two-dimensional rigid rectangular liquid tanks with a bottom-mounted submerged block is numerically simulated. The Galerkin-weighted-residual based finite element method (FEM) is used for solving the governing Laplace equation with fully nonlinear free surface boundary conditions and also for velocity recovery. Based on the mixed Eulerian-Lagrangian (MEL) method, a fourth order explicit Runge-Kutta scheme is used for the time-stepping integration of free surface boundary conditions. A cubic-spline fitted regridding technique is used at every time step to eliminate possible numerical instabilities on account of Lagrangian node induced mesh distortion. An artificial surface damping term is used to mimic the viscosity induced damping. Three different earthquake motions characterized on the basis of low, intermediate and high frequency contents are used to study the effect of frequency content on the nonlinear dynamic response of this tank-liquid-submerged block system. The effect of the submerged block on the impulsive and convective response components of the hydrodynamic forces manifested in terms of base shear, overturning base moment and pressure distribution along the tank wall as well as the block wall has been quantified vis-a-vis frequency content of ground motions. It is observed that the convective response of this tank-liquid system is highly sensitive to the frequency content of the ground motion.

  18. Anaesthesia ventilators

    PubMed Central

    Jain, Rajnish K; Swaminathan, Srinivasan

    2013-01-01

    Anaesthesia ventilators are an integral part of all modern anaesthesia workstations. Automatic ventilators in the operating rooms, which were very simple with few modes of ventilation when introduced, have become very sophisticated with many advanced ventilation modes. Several systems of classification of anaesthesia ventilators exist based upon various parameters. Modern anaesthesia ventilators have either a double circuit, bellow design or a single circuit piston configuration. In the bellows ventilators, ascending bellows design is safer than descending bellows. Piston ventilators have the advantage of delivering accurate tidal volume. They work with electricity as their driving force and do not require a driving gas. To enable improved patient safety, several modifications were done in circle system with the different types of anaesthesia ventilators. Fresh gas decoupling is a modification done in piston ventilators and in descending bellows ventilator to reduce th incidence of ventilator induced volutrauma. In addition to the conventional volume control mode, modern anaesthesia ventilators also provide newer modes of ventilation such as synchronised intermittent mandatory ventilation, pressure-control ventilation and pressure-support ventilation (PSV). PSV mode is particularly useful for patients maintained on spontaneous respiration with laryngeal mask airway. Along with the innumerable benefits provided by these machines, there are various inherent hazards associated with the use of the ventilators in the operating room. To use these workstations safely, it is important for every Anaesthesiologist to have a basic understanding of the mechanics of these ventilators and breathing circuits. PMID:24249886

  19. Hypothermic liquid ventilation prevents early hemodynamic dysfunction and cardiovascular mortality after coronary artery occlusion complicated by cardiac arrest in rabbits

    PubMed Central

    Darbera, Lys; Chenoune, Mourad; Lidouren, Fanny; Kohlhauer, Matthias; Adam, Clovis; Bruneval, Patrick; Ghaleh, Bijan; Dubois-Randé, Jean-Luc; Carli, Pierre; Vivien, Benoit; Ricard, Jean-Damien; Berdeaux, Alain; Tissier, Renaud

    2013-01-01

    Objective Ultrafast and whole-body cooling can be induced by total liquid ventilation (TLV) with temperature-controlled perfluorocarbons. Our goal was to determine whether this can afford maximal cardio- and neuroprotections through cooling rapidity when coronary occlusion is complicated by cardiac arrest. Design Prospective, randomized animal study. Setting Academic research laboratory. Subjects Male New-Zealand rabbits. Interventions Chronically instrumented rabbits were submitted to coronary artery occlusion and ventricular fibrillation. After 8-min of cardiac arrest, animals were resuscitated and submitted to a normothermic follow-up (Control group) or to 3-h of mild hypothermia induced by TLV (TLV group) or by combination of cold saline infusion and cold blankets application (Saline group). Coronary reperfusion was permitted 40-min after the onset of occlusion. After awakening, rabbits were followed during 7 days. Measurements and main results Ten animals were resuscitated in each group. In the Control group, all animals secondarily died from cardiac/respiratory failure (8/10) or neurological dysfunction (2/10). In the Saline group, the target temperature of 32°C was achieved within 30–45 min after cooling initiation. This slightly reduced infarct size vs Control (41±16% vs 54±8% of risk zone, respectively; p<0.05) but failed to significantly improve cardiac output, neurological recovery and survival rate (3 survivors, 6 death from cardiac/respiratory failure and 1 from neurological dysfunction). Conversely, the 32°C temperature was achieved within 5–10 min in the TLV group. This led to a dramatic reduction in infarct size (13±4%; p<0.05 vs other groups) and improvements in cardiac output, neurological recovery and survival (8 survivors, 2 deaths from cardiac/respiratory failure). Conclusions Achieving hypothermia rapidly is critical to improve the cardiovascular outcome after cardiac arrest with underlying myocardial infarction. PMID:24126441

  20. Serpentine diffusion trajectories and the Ouzo effect in partially miscible ternary liquid mixtures.

    PubMed

    Krishna, Rajamani

    2015-11-07

    This work investigates the transient equilibration process when partially miscible ternary liquid mixtures of two different compositions are brought into contact with each other. Diffusional coupling effects are shown to become increasingly significant as the mixture compositions approach the meta-stable regions of the phase equilibrium diagrams. The proper modelling of coupled diffusion phenomena requires the use of a Fick diffusivity matrix [D], with inclusion of non-zero off-diagonal elements. The primary objective of this article is to develop a simple, robust, procedure for the estimation of the matrix [D], using the Maxwell-Stefan (M-S) formulation as a convenient starting point. In the developed simplified approach, the Fick diffusivity matrix [D] is expressed as the product of a scalar diffusivity and the matrix of thermodynamic correction factors [Γ]. By detailed examination of experimental data for the matrix [D] in a wide variety of ternary mixtures, it is deduced that the major contribution of diffusional coupling arises from the contributions of non-ideal solution thermodynamics, quantified by the matrix of thermodynamic correction factors [Γ]. An important consequence of strong thermodynamic coupling is that equilibration trajectories are serpentine in shape and may exhibit incursions into meta-stable zones opening up the possibility of spontaneous emulsification and the Ouzo effect. If diffusional coupling effects are ignored, the equilibration trajectory is linear in composition space. For a wide variety of partially miscible ternary mixtures, it is demonstrated that the corresponding linear equilibration trajectories do not anticipate the possibility of emulsification.

  1. Vibration mitigation in partially liquid-filled vessel using passive energy absorbers

    NASA Astrophysics Data System (ADS)

    Farid, M.; Levy, N.; Gendelman, O. V.

    2017-10-01

    We consider possible solutions for vibration mitigation in reduced-order model (ROM) of partially filled liquid tank under impulsive forcing. Such excitations may lead to strong hydraulic impacts applied to the tank inner walls. Finite stiffness of the tank walls is taken into account. In order to mitigate the dangerous internal stresses in the tank walls, we explore both linear (Tuned Mass Damper) and nonlinear (Nonlinear Energy Sink) passive vibration absorbers; mitigation performance in both cases is examined numerically. The liquid sloshing mass is modeled by equivalent mass-spring-dashpot system, which can both perform small-amplitude linear oscillations and hit the vessel walls. We use parameters of the equivalent mass-spring-dashpot system for a well-explored case of cylindrical tanks. The hydraulic impacts are modeled by high-power potential and dissipation functions. Critical location in the tank structure is determined and expression of the corresponding local mechanical stress is derived. We use finite element approach to assess the natural frequencies for specific system parameters. Numerical evaluation criteria are suggested to determine the energy absorption performance.

  2. Partial delignification of wood and membrane preparation using a quaternary ammonium ionic liquid

    PubMed Central

    Miao, Jiaojiao; Yu, Yongqi; Jiang, Zeming; Tang, Lan; Zhang, Liping

    2017-01-01

    This work determined that southern yellow pine wood can almost be completely dissolved in the quaternary ammonium ionic liquid tetrabutylammonium acetate with dimethyl sulfoxide (in a 2:8 mass ratio), after minimal grinding, upon heating at 85 °C for three dissolution/reconstitution cycles, each 1.5 h. Approximately 34.6% of the native lignin and 67.4% of the native carbohydrates present in the original wood can subsequently be extracted, respectively, and were assessed. A gradual decrease in lignin with increased extraction cycles resulted in increased crystallinity index of the cellulose II in the cellulose-rich residue, as confirmed by X-ray diffraction. An increasingly homogeneous macrostructure in the cellulose-rich residue was also evident from scanning electron microscopy images. Membranes cast directly from either wood or cellulose-rich residue solutions in the same tetrabutylammonium acetate/dimethyl sulfoxide system, were prepared using a papermaking-like process. Morphological and mechanical studies indicated that lignin extraction made the membranes more uniform and flexible. Systematic increases in the fibril lengths and orientations of the recovered materials were also found with decreasing lignin contents on the basis of atomic force microscopy analysis. This work demonstrates that relatively efficient partial separation of pine wood and subsequent membrane preparation are possible using a quaternary ammonium ionic liquid. PMID:28266507

  3. Partial delignification of wood and membrane preparation using a quaternary ammonium ionic liquid

    NASA Astrophysics Data System (ADS)

    Miao, Jiaojiao; Yu, Yongqi; Jiang, Zeming; Tang, Lan; Zhang, Liping

    2017-03-01

    This work determined that southern yellow pine wood can almost be completely dissolved in the quaternary ammonium ionic liquid tetrabutylammonium acetate with dimethyl sulfoxide (in a 2:8 mass ratio), after minimal grinding, upon heating at 85 °C for three dissolution/reconstitution cycles, each 1.5 h. Approximately 34.6% of the native lignin and 67.4% of the native carbohydrates present in the original wood can subsequently be extracted, respectively, and were assessed. A gradual decrease in lignin with increased extraction cycles resulted in increased crystallinity index of the cellulose II in the cellulose-rich residue, as confirmed by X-ray diffraction. An increasingly homogeneous macrostructure in the cellulose-rich residue was also evident from scanning electron microscopy images. Membranes cast directly from either wood or cellulose-rich residue solutions in the same tetrabutylammonium acetate/dimethyl sulfoxide system, were prepared using a papermaking-like process. Morphological and mechanical studies indicated that lignin extraction made the membranes more uniform and flexible. Systematic increases in the fibril lengths and orientations of the recovered materials were also found with decreasing lignin contents on the basis of atomic force microscopy analysis. This work demonstrates that relatively efficient partial separation of pine wood and subsequent membrane preparation are possible using a quaternary ammonium ionic liquid.

  4. Contact line instability of a liquid rivulet partially wetting an inclined plane

    NASA Astrophysics Data System (ADS)

    Gonzalez, A. G.; Diez, J. A.; Kondic, L.

    2011-11-01

    We analyze the stability of a liquid rivulet of cross section, A, positioned across a plane with inclination angle, α. The liquid partially wets the substrate with a static contact angle, θ0, when the substrate is horizontal. The contact line stability is studied using the lubrication approximation and with a slip model. Both normal and parallel components of gravity are included A static solution exists for small α's and its linear stability is considered. We use an pseudo-spectral Chebyshev method with a combination of basis functions that automatically satisfies the conditions at the contact lines. We analyze the effects of A, θ0 and α on the predictions of the model, such as stability regions, the maximum growth rate and the behavior of most unstable perturbation. Experiments with silicone oils spreading on a coated glass substrate are considered for a number of different fluid volumes and α's. We find a good agreement between the wavelength of maximum growth predicted by the model and the experimental average distance between drops. Supported by ANPCyT-PICT2498/06, CONICET(Argentina) and NSF Grant DMS-0908158.

  5. Partial transient liquid phase diffusion bonding of Zircaloy-4 to stabilized austenitic stainless steel 321

    SciTech Connect

    Atabaki, M. Mazar; Hanzaei, A. Talebi

    2010-10-15

    An innovative method was applied for bonding Zircaloy-4 to stabilized austenitic stainless steel 321 using an active titanium interlayer. Specimens were joined by a partial transient liquid phase diffusion bonding method in a vacuum furnace at different temperatures under 1 MPa dynamic pressure of contact. The influence of different bonding temperatures on the microstructure, microindentation hardness, joint strength and interlayer thickness has been studied. The diffusion of Fe, Cr, Ni and Zr has been investigated by scanning electron microscopy and energy dispersive spectroscopy elemental analyses. Results showed that control of the heating and cooling rate and 20 min soaking at 1223 K produces a perfect joint. However, solid-state diffusion of the melting point depressant elements into the joint metal causes the solid/liquid interface to advance until the joint is solidified. The tensile strength of all the bonded specimens was found around 480-670 MPa. Energy dispersive spectroscopy studies indicated that the melting occurred along the interface of the bonded specimens as a result of the transfer of atoms between the interlayer and the matrix during bonding. This technique provides a reliable method of bonding zirconium alloy to stainless steel.

  6. Statistical analysis of liquid seepage in partially saturated heterogeneous fracture systems

    SciTech Connect

    Liou, Tai -Sheng

    1999-12-01

    Field evidence suggests that water flow in unsaturated fracture systems may occur along fast preferential flow paths. However, conventional macroscale continuum approaches generally predict the downward migration of water as a spatially uniform wetting front subjected to strong inhibition into the partially saturated rock matrix. One possible cause of this discrepancy may be the spatially random geometry of the fracture surfaces, and hence, the irregular fracture aperture. Therefore, a numerical model was developed in this study to investigate the effects of geometric features of natural rock fractures on liquid seepage and solute transport in 2-D planar fractures under isothermal, partially saturated conditions. The fractures were conceptualized as 2-D heterogeneous porous media that are characterized by their spatially correlated permeability fields. A statistical simulator, which uses a simulated annealing (SA) algorithm, was employed to generate synthetic permeability fields. Hypothesized geometric features that are expected to be relevant for seepage behavior, such as spatially correlated asperity contacts, were considered in the SA algorithm. Most importantly, a new perturbation mechanism for SA was developed in order to consider specifically the spatial correlation near conditioning asperity contacts. Numerical simulations of fluid flow and solute transport were then performed in these synthetic fractures by the flow simulator TOUGH2, assuming that the effects of matrix permeability, gas phase pressure, capillary/permeability hysteresis, and molecular diffusion can be neglected. Results of flow simulation showed that liquid seepage in partially saturated fractures is characterized by localized preferential flow, along with bypassing, funneling, and localized ponding. Seepage pattern is dominated by the fraction of asperity contracts, and their shape, size, and spatial correlation. However, the correlation structure of permeability field is less important

  7. [Effect of oxygen tubing connection site on percutaneous oxygen partial pressure and percutaneous carbon dioxide partial pressure in patients with chronic obstructive pulmonary disease during noninvasive positive pressure ventilation].

    PubMed

    Mi, S; Zhang, L M

    2017-04-12

    Objective: We evaluated the effects of administering oxygen through nasal catheters inside the mask or through the mask on percutaneous oxygen partial pressure (PcO(2))and percutaneous carbon dioxide partial pressure (PcCO(2)) during noninvasive positive pressure ventilation (NPPV) to find a better way of administering oxygen, which could increase PcO(2) by increasing the inspired oxygen concentration. Methods: Ten healthy volunteers and 9 patients with chronic obstructive pulmonary disease complicated by type Ⅱ respiratory failure were included in this study. Oxygen was administered through a nasal catheter inside the mask or through the mask (oxygen flow was 3 and 5 L/min) during NPPV. PcO(2) and PcCO(2) were measured to evaluate the effects of administering oxygen through a nasal catheter inside the mask or through the mask, indirectly reflecting the effects of administering oxygen through nasal catheter inside the mask or through the mask on inspired oxygen concentration. Results: Compared to administering oxygen through the mask during NPPV, elevated PcO(2) was measured in administering oxygen through the nasal catheter inside the mask, and the differences were statistically significant (P<0.05). At the same time, there was no significant change in PcCO(2) (P>0.05). Conclusion: Administering oxygen through a nasal catheter inside the mask during NPPV increased PcO(2) by increasing the inspired oxygen concentration but did not increase PcCO(2). This method of administering oxygen could conserve oxygen and be suitable for family NPPV. Our results also provided theoretical basis for the development of new masks.

  8. Assisted Ventilation.

    PubMed

    Dries, David J

    2016-01-01

    Controlled Mechanical Ventilation may be essential in the setting of severe respiratory failure but consequences to the patient including increased use of sedation and neuromuscular blockade may contribute to delirium, atelectasis, and diaphragm dysfunction. Assisted ventilation allows spontaneous breathing activity to restore physiological displacement of the diaphragm and recruit better perfused lung regions. Pressure Support Ventilation is the most frequently used mode of assisted mechanical ventilation. However, this mode continues to provide a monotonous pattern of support for respiration which is normally a dynamic process. Noisy Pressure Support Ventilation where tidal volume is varied randomly by the ventilator may improve ventilation and perfusion matching but the degree of support is still determined by the ventilator. Two more recent modes of ventilation, Proportional Assist Ventilation and Neurally Adjusted Ventilatory Assist (NAVA), allow patient determination of the pattern and depth of ventilation. Proposed advantages of Proportional Assist Ventilation and NAVA include decrease in patient ventilator asynchrony and improved adaptation of ventilator support to changing patient demand. Work of breathing can be normalized with these modes as well. To date, however, a clear pattern of clinical benefit has not been demonstrated. Existing challenges for both of the newer assist modes include monitoring patients with dynamic hyperinflation (auto-positive end expiratory pressure), obstructive lung disease, and air leaks in the ventilator system. NAVA is dependent on consistent transduction of diaphragm activity by an electrode system placed in the esophagus. Longevity of effective support with this technique is unclear.

  9. The distribution of partial melt in a granitic system: The application of liquid phase sintering theory

    NASA Astrophysics Data System (ADS)

    Jurewicz, Stephen R.; Watson, E. Bruce

    1985-05-01

    Two series of experiments, four crystallization and four partial melting, were performed at 1000°C and 10 kilobars in the quartz-alkali feldspar-granitic melt system in order to determine the equilibrium melt distribution and textural adjustment processes. The melt distribution in both types of experiments was characterized by melt residing at grain edge intersections and in a few large pools scattered throughout the sample. Wetting angle measurements from both sets of experiments gave values of 44, 49, and 59 degrees for the feldspar/feldspar, feldspar/quartz, and quartz/quartz wetting angles, respectively. Interparticle welding, a process consistent with the measured wetting angles, resulted in the formation of a skeleton of solid grains with very few unattached grains in any sample. Analysis of wetting angle distributions indicates that the longest duration experiments closely approached textural equilibrium and that the distributions of observed wetting angles from both sets of experiments were nearly identical. Measurement of quartz grain sizes from the 2, 4, 7, and 14-day crystallization experiments revealed: 1) a probable cube root of time dependence for the quartz growth rate; 2) a decrease in the number of quartz grains per square micron with increasing time; 3) a normalized distribution of grain sizes that appeared stationary in time. These results were shown to be consistent with the processes observed during the liquid phase sintering of ceramic materials and suggest that identical processes may occur in natural partially-molten systems. Finally, it was shown that interfacial energy considerations lead to a model of interparticle welding (clustering) in which it is discovered that there is an equilibrium melt fraction stable along grain edges of a partially-molten crystalline aggregate. This melt fraction may be greater, equal to, or less than the equilibrium fraction of melt dictated by the pressure, temperature, and chemical potential conditions. If

  10. Partial enzymatic elimination and quantification of sarcosine from alanine using liquid chromatography-tandem mass spectrometry.

    PubMed

    Burton, Casey; Gamagedara, Sanjeewa; Ma, Yinfa

    2013-04-01

    Since sarcosine and D,L-alanine co-elute on reversed-phase high-performance liquid chromatography (HPLC) columns and the tandem mass spectrometer cannot differentiate them due to equivalent parent and fragment ions, derivatization is often required for analysis of sarcosine in LC/MS systems. This study offers an alternative to derivatization by employing partial elimination of sarcosine by enzymatic oxidation. The decrease in apparent concentration from the traditionally merged sarcosine-alanine peak associated with the enzymatic elimination has been shown to be proportional to the total sarcosine present (R(2) = 0.9999), allowing for determinations of urinary sarcosine. Sarcosine oxidase was shown to eliminate only sarcosine in the presence of D,L-alanine, and was consequently used as the selective enzyme. This newly developed technique has a method detection limit of 1 μg/L (parts per billion) with a linear range of 3 ppb-1 mg/L (parts per million) in urine matrices. The method was further validated through spiked recoveries of real urine samples, as well as the analysis of 35 real urine samples. The average recoveries for low, middle, and high sarcosine concentration spikes were 111.7, 90.8, and 90.1 %, respectively. In conclusion, this simple enzymatic approach coupled with HPLC/MS/MS is able to resolve sarcosine from D,L-alanine leading to underivatized quantification of sarcosine.

  11. A comparative study of two generation partial light intensity imager based on liquid crystal

    NASA Astrophysics Data System (ADS)

    Tang, Yuanhe; Yang, Xusan; Gao, Haiyang; Wu, Yong; Wang, Shuiwei; Cao, Xiangang; Jia, Wanli

    2013-06-01

    Two generations of prototype partial light intensity imager (PLII) based on liquid crystal (LC) are designed and implemented to achieve imaging of objects with strong light illuminations. They can both realize object imaging by controlling each pixel of the LC for a strong light intensity of larger than 2.2×105lx. There are two ways to control the LC's transmission. One way is to adjust the applied voltage to the LC selected (Sony LCX029AMT) that realizes an adjutable light transmission of 1.28-25.60%. Another way is to change the angle of polarization of either the polarizer or analyzer and obtain a range of the light transmission of 3.35-17.73%. The 1st generation of PLII uses a closed feedback loop to control the imaging system with one CCD which requires two frames of image to realize the image gating function. The 2nd generation is an upgraded version that employs two CCDs to improve the real-time imaging performance. While the 1st generation has a lower cost and smaller volume than the 2nd generation does, the 2nd generation has a capability to more easily realize image gating at a video frequency which only requires one single image frame because of the use of two CCDs. The modulate transfer function (MTF) of the two PLII systems using the two transmission control methods is 0.586 and 0.480 respectively.

  12. Molecular dynamics simulations of liquid binary mixtures: Partial properties of mixing and transport coefficients

    NASA Astrophysics Data System (ADS)

    Heyes, D. M.

    1992-02-01

    Equilibrium molecular dynamics (MD) computer simulations have been used to determine the transport coefficients of model Ar-Kr, Ar-CH4, and CH4-N2 mixtures at a large number of liquid and dense fluid state points for which experimental data are available. Both species in each mixture are represented by single-site Lennard-Jones pair potentials with Lorentz-Berthelot mixing rules for the unlike interactions. Green-Kubo formulas and mean-square displacements are used to calculate the self-diffusion coefficients for each species and mutual-diffusion coefficients. The shear and bulk moduli and viscosities, thermal conductivity and the thermal diffusion coefficient are determined by Green-Kubo in the [NVE] and [NVT] ensembles. The thermotransport coefficients employ a rigorous definition for the heat flux, which includes the partial enthalpy of the two species, used for the first time to compute these transport coefficients. The partial volumes and enthalpies, and chemical potentials for each species, were obtained from separate computations carried out at constant pressure in the [NPT] ensemble. The simulated density at fixed pressure, shear viscosity, and thermal conductivity of the Ar-Kr mixtures are in excellent agreement with experiment. However, the bulk viscosity shows a significant qualitative difference in the composition and temperature dependence (the latter even in the single component fluids). Agreement with experiment deteriorates as the quasispherical molecules progressively depart from spherical shape. For Ar-CH4 the density (obtained using [NPT] MD) is in good agreement with experiment, whereas the shear viscosity is in progressively poorer agreement with increasing methane content. This is caused by an overestimation of the methane viscosity (˜50% higher than experiment for pure methane). For CH4-N2 there are substantial differences between the simulated quantities and experiment. The average simulated densities are ˜5% higher than experiment over a

  13. Wetting phenomenon in the liquid-vapor phase coexistence of a partially miscible Lennard-Jones binary mixture

    NASA Astrophysics Data System (ADS)

    Díaz-Herrera, Enrique; Moreno-Razo, J. Antonio; Ramírez-Santiago, Guillermo

    2004-11-01

    We have carried out extensive equilibrium molecular dynamics simulations to study the structure and the interfacial properties in the liquid-vapor phase coexistence of partially miscible binary Lennard-Jones mixtures. By analyzing the structural properties as a function of the miscibility parameter, α , we found that at relatively low temperatures the system separates forming a liquid A-liquid B interface in coexistence with the vapor phase. At higher temperatures and, 0<α⩽0.5 , we found a temperature range, Tw*(α)⩽T*liquid phases are wet by the vapor phase. Here, Tw*(α) represents the wetting transition temperature and TCons*(α) is the consolute temperature of the mixture. However, for 0.5<α<1 , no wetting phenomenon occurs. For the particular value, α=0.25 , we analyzed quantitatively the T* versus ρ* , and P* versus T* phase diagrams and found, Tc*≃1.25 , and TCons*≃1.25 . We also studied quantitatively, as a function of temperature, the surface tension and the adsorption of molecules at the liquid-liquid interface. It was found that the adsorption shows a jump from a finite negative value up to minus infinity, when the vapor wets the liquid phases, suggesting that the wetting transition is of first order. The calculated phase diagram, together with the wetting phenomenon, strongly suggests the existence of a tricritical point. These results agree well with some experiments carried out in fluid binary mixtures.

  14. Pressure dependence of the electro-optic response function in partially exposed polymer dispersed ferroelectric liquid crystals

    NASA Technical Reports Server (NTRS)

    Parmar, D. S.; Holmes, H. K.

    1993-01-01

    Ferroelectric liquid crystals in a new configuration, termed partially exposed polymer dispersed ferroelectric liquid crystal (PEPDFLC), respond to external pressures and demonstrate pressure-induced electro-optic switching response. When the PEPDFLC thin film is sandwiched between two transparent conducting electrodes, one a glass plate and the other a flexible sheet such as polyvenylidene fluoride, the switching characteristics of the thin film are a function of the pressure applied to the flexible transparent electrode and the bias voltage across the electrodes. Response time measurements reveal a linear dependence of the change in electric field with external pressure.

  15. Free films of a partially wetting liquid under the influence of a propagating MHz surface acoustic wave

    NASA Astrophysics Data System (ADS)

    Altshuler, Gennady; Manor, Ofer

    2016-07-01

    We use both theory and experiment to study the response of thin and free films of a partially wetting liquid to a MHz vibration, propagating in the solid substrate in the form of a Rayleigh surface acoustic wave (SAW). We generalise the previous theory for the response of a thin fully wetting liquid film to a SAW by including the presence of a small but finite three phase contact angle between the liquid and the solid. The SAW in the solid invokes a convective drift of mass in the liquid and leaks sound waves. The dynamics of a film that is too thin to support the accumulation of the sound wave leakage is governed by a balance between the drift and capillary stress alone. We use theory to demonstrate that a partially wetting liquid film, supporting a weak capillary stress, will spread along the path of the SAW. A partially wetting film, supporting an appreciable capillary stress, will however undergo a concurrent dynamic wetting and dewetting at the front and the rear, respectively, such that the film will displace, rather than spread, along the path of the SAW. The result of the theory for a weak capillary stress is in agreement with the previous experimental and theoretical studies on the response of thin silicon oil films to a propagating SAW. No corresponding previous results exist for the case of an appreciable capillary stress. We thus complement the large capillary limit of our theory by undertaking an experimental procedure where we explore the response of films of water and a surfactant solutions to a MHz SAW, which is found to be in qualitative agreement with the theory at this limit.

  16. The effect of various quantum mechanically derived partial atomic charges on the bulk properties of chloride-based ionic liquids

    NASA Astrophysics Data System (ADS)

    Zolghadr, Amin Reza; Ghatee, Mohammad Hadi; Moosavi, Fatemeh

    2016-08-01

    Partial atomic charges using various quantum mechanical calculations for [Cnmim]Cl (n = 1, 4) ionic liquids (ILs) are obtained and used for development of molecular dynamics simulation (MD) force fields. The isolated ion pairs are optimized using HF, B3LYP, and MP2 methods for electronic structure with 6-311++G(d,p) basis set. Partial atomic charges are assigned to the atomic center with CHELPG and NBO methods. The effect of these sets of partial charges on the static and dynamic properties of ILs is evaluated by performing a series of MD simulations and comparing the essential thermodynamic properties with the available experimental data and available molecular dynamics simulation results. In contrast to the general trends reported for ionic liquids with BF4, PF6, and iodide anions (in which restrained electrostatic potential (RESP) charges are preferred), partial charges derived by B3LYP-NBO method are relatively good in prediction of the structural, dynamical, and thermodynamic energetic properties of the chloride based ILs.

  17. Demand Controlled Ventilation and Classroom Ventilation

    SciTech Connect

    Fisk, William J.; Mendell, Mark J.; Davies, Molly; Eliseeva, Ekaterina; Faulkner, David; Hong, Tienzen; Sullivan, Douglas P.

    2012-05-01

    This document summarizes a research effort on demand controlled ventilation and classroom ventilation. The research on demand controlled ventilation included field studies and building energy modeling.

  18. Flow patterns in a rotating horizontal cylinder partially filled with liquid

    NASA Astrophysics Data System (ADS)

    Kozlov, Victor; Polezhaev, Denis

    2015-07-01

    The dynamics of an annular layer of low-viscosity liquid inside a rapidly rotating horizontal cylinder is experimentally studied. Under gravity, the liquid performs forced azimuthal oscillations in the cavity frame. We examined the stability of the two-dimensional azimuthal flow and discovered two novel types of axisymmetric liquid flows. First, a large-scale axially symmetric flow is excited near the end walls. The inertial modes generated in the corner regions are proven to be responsible for such a flow. Second, a small-scale flow in the form of the Taylor-Gortler vortices appears due to the centrifugal instability of the oscillatory liquid flow. The spatial period of the vortices is in qualitative agreement with the data obtained in the experimental and numerical studies of cellular flow in librating containers.

  19. Electro-optic properties of nematic and ferroelectric liquid crystalline nanocolloids doped with partially reduced graphene oxide

    NASA Astrophysics Data System (ADS)

    Lapanik, Valeri; Timofeev, Sergei; Haase, Wolfgang

    2016-02-01

    Flakes of partially reduced graphene oxide (PRGO) were doped in nematic liquid crystals (NLCs) and ferroelectric liquid crystals (FLCs), respectively. The dielectric and electro-optical properties of NLCs doped with those flakes have been investigated. Threshold voltage and switching times are reduced by 30%-50%. This is primarily due to the decrease of the elastic properties of the nanocolloids compared to the non-doped nematics. The influence of the PRGO flakes on the spontaneous polarization, tilt angle and switching time of FLCs was investigated too. Such flakes reduce the response time by 40%-60%, increases spontaneous polarization by 20%-25% and increase the tilt angle by 15%-20%.

  20. [Principles and function of mechanical ventilation: classification and modes of ventilators].

    PubMed

    Kelbel, C; Huntemann, M; Lorenz, J

    2006-04-01

    A spectrum of diseases is associated with the necessity for partial or total support of pulmonary ventilation. The insight into the function of ventilators and their modes reduces the spectrum of ventilatory support to a few basic principles. The knowledge enables the pulmonary intensivist to adapt mechanical ventilation to the individual patient's needs. This overview describes the technical aspects of mechanical ventilation and summarizes the variety of specific modes implied.

  1. Ventilation Model

    SciTech Connect

    V. Chipman

    2002-10-05

    The purpose of the Ventilation Model is to simulate the heat transfer processes in and around waste emplacement drifts during periods of forced ventilation. The model evaluates the effects of emplacement drift ventilation on the thermal conditions in the emplacement drifts and surrounding rock mass, and calculates the heat removal by ventilation as a measure of the viability of ventilation to delay the onset of peak repository temperature and reduce its magnitude. The heat removal by ventilation is temporally and spatially dependent, and is expressed as the fraction of heat carried away by the ventilation air compared to the fraction of heat produced by radionuclide decay. One minus the heat removal is called the wall heat fraction, or the remaining amount of heat that is transferred via conduction to the surrounding rock mass. Downstream models, such as the ''Multiscale Thermohydrologic Model'' (BSC 2001), use the wall heat fractions as outputted from the Ventilation Model to initialize their post-closure analyses. The Ventilation Model report was initially developed to analyze the effects of preclosure continuous ventilation in the Engineered Barrier System (EBS) emplacement drifts, and to provide heat removal data to support EBS design. Revision 00 of the Ventilation Model included documentation of the modeling results from the ANSYS-based heat transfer model. The purposes of Revision 01 of the Ventilation Model are: (1) To validate the conceptual model for preclosure ventilation of emplacement drifts and verify its numerical application in accordance with new procedural requirements as outlined in AP-SIII-10Q, Models (Section 7.0). (2) To satisfy technical issues posed in KTI agreement RDTME 3.14 (Reamer and Williams 2001a). Specifically to demonstrate, with respect to the ANSYS ventilation model, the adequacy of the discretization (Section 6.2.3.1), and the downstream applicability of the model results (i.e. wall heat fractions) to initialize post

  2. Mechanical Ventilation

    MedlinePlus

    ... cared for in a hospital’s intensive care unit (ICU). People who need a ventilator for a longer time may be in a regular unit of a hospital, a rehabilitation facility, or cared for at home. Why are ...

  3. Salting-out assisted liquid-liquid extraction and partial least squares regression to assay low molecular weight polycyclic aromatic hydrocarbons leached from soils and sediments.

    PubMed

    Bressan, Lucas P; do Nascimento, Paulo Cícero; Schmidt, Marcella E P; Faccin, Henrique; de Machado, Leandro Carvalho; Bohrer, Denise

    2017-02-15

    A novel method was developed to determine low molecular weight polycyclic aromatic hydrocarbons in aqueous leachates from soils and sediments using a salting-out assisted liquid-liquid extraction, synchronous fluorescence spectrometry and a multivariate calibration technique. Several experimental parameters were controlled and the optimum conditions were: sodium carbonate as the salting-out agent at concentration of 2molL(-1), 3mL of acetonitrile as extraction solvent, 6mL of aqueous leachate, vortexing for 5min and centrifuging at 4000rpm for 5min. The partial least squares calibration was optimized to the lowest values of root mean squared error and five latent variables were chosen for each of the targeted compounds. The regression coefficients for the true versus predicted concentrations were higher than 0.99. Figures of merit for the multivariate method were calculated, namely sensitivity, multivariate detection limit and multivariate quantification limit. The selectivity was also evaluated and other polycyclic aromatic hydrocarbons did not interfere in the analysis. Likewise, high performance liquid chromatography was used as a comparative methodology, and the regression analysis between the methods showed no statistical difference (t-test). The proposed methodology was applied to soils and sediments of a Brazilian river and the recoveries ranged from 74.3% to 105.8%. Overall, the proposed methodology was suitable for the targeted compounds, showing that the extraction method can be applied to spectrofluorometric analysis and that the multivariate calibration is also suitable for these compounds in leachates from real samples.

  4. Salting-out assisted liquid-liquid extraction and partial least squares regression to assay low molecular weight polycyclic aromatic hydrocarbons leached from soils and sediments

    NASA Astrophysics Data System (ADS)

    Bressan, Lucas P.; do Nascimento, Paulo Cícero; Schmidt, Marcella E. P.; Faccin, Henrique; de Machado, Leandro Carvalho; Bohrer, Denise

    2017-02-01

    A novel method was developed to determine low molecular weight polycyclic aromatic hydrocarbons in aqueous leachates from soils and sediments using a salting-out assisted liquid-liquid extraction, synchronous fluorescence spectrometry and a multivariate calibration technique. Several experimental parameters were controlled and the optimum conditions were: sodium carbonate as the salting-out agent at concentration of 2 mol L- 1, 3 mL of acetonitrile as extraction solvent, 6 mL of aqueous leachate, vortexing for 5 min and centrifuging at 4000 rpm for 5 min. The partial least squares calibration was optimized to the lowest values of root mean squared error and five latent variables were chosen for each of the targeted compounds. The regression coefficients for the true versus predicted concentrations were higher than 0.99. Figures of merit for the multivariate method were calculated, namely sensitivity, multivariate detection limit and multivariate quantification limit. The selectivity was also evaluated and other polycyclic aromatic hydrocarbons did not interfere in the analysis. Likewise, high performance liquid chromatography was used as a comparative methodology, and the regression analysis between the methods showed no statistical difference (t-test). The proposed methodology was applied to soils and sediments of a Brazilian river and the recoveries ranged from 74.3% to 105.8%. Overall, the proposed methodology was suitable for the targeted compounds, showing that the extraction method can be applied to spectrofluorometric analysis and that the multivariate calibration is also suitable for these compounds in leachates from real samples.

  5. Computational Model for Liquid Phase Electro-Epitaxial Crystal Growth on Partially Masked Substrate

    NASA Astrophysics Data System (ADS)

    Khenner, Mikhail; Braun, Richard J.

    2003-03-01

    A computational model for semiconductor crystal growth on a partially masked substrate under simplified LPEE conditions is developed. The model assumes isothermal diffusional growth from molten metal solution, which is enhanced by applied DC current through crystal/melt interface. Finite-difference, front-tracking method is used to numerically evolve the interface according to the set of governing partial differential equations and boundary conditions. Computed examples show strong influence of the electromigration on growth rates in vertical and lateral directions and the dependence of growth on electrical conductivities of substrate and mask materials as well as on wetting contact angle. The study presented is the first attempt to model LPEE growth on patterned substrates commonly employed in semiconductor industry.

  6. Study of non-Fermi Liquid behavior from partial nesting in multi-orbital superconductors

    NASA Astrophysics Data System (ADS)

    Setty, Chandan; Phillips, Philip

    Partial nesting between two connected or disconnected regions of the Fermi surface leads to fractional powers of the Coulomb scattering lifetime as a function of temperature and frequency. This result is first demonstrated for a toy band structure where partial nesting occurs within a single band and between different regions of the Brillouin zone. A comparison is then made to a multiband scenario by studying the scattering rate of an effective two orbital model that was proposed in the context of multi-orbital superconductors. In the process, various model independent factors affecting the temperature exponent, n, are identified. The logarithmically divergent contributions of the lowest order vertex correction to the multi-orbital susceptibility, and the role played by nesting in suppressing these divergences is analyzed. The relevance of these results is discussed keeping the recently observed anomalous resistivity in the Co doped Iron superconductor LiFeAs as a backdrop.

  7. Thin liquid film in polymer tubing : dynamics and dewetting in partial wetting condition

    NASA Astrophysics Data System (ADS)

    Hayoun, Pascaline; Letailleur, Alban; Teisseire, Jérémie; Verneuil, Emilie; Lequeux, François; Barthel, Etienne

    2015-11-01

    Polymers such as PVC and Silicone are low cost materials widely used in industry to produce tubing for fluid transport. Most of these applications involve repeated, intermittent flow of liquids which can lead to unwanted contamination. This study aims at better understanding contamination mechanisms during intermittent flow in polymer tubing, and at elucidating the relation between flow, wetting and contamination. We experimentally and theoretically investigate, flow regimes as well as dewetting process at the triple line induced by gravity flow of a vertical liquid slug in a cylindrical geometry. Our results for Newtonian fluids evidence a succession of thick film formation, hydraulic jump creation in the thickness profile, oscillatory regime and destabilization leading to substrate contamination. In order to understand theoretically the flow, one crucial quantity to assess is the film thickness in the inside of the tube. Based on an absorption measurement method, we provide explanations for behaviors and flow regimes observed experimentally.

  8. Analytical method for the attitude stability of partially liquid filled spacecraft with flexible appendage

    NASA Astrophysics Data System (ADS)

    Yan, Yulong; Yue, Baozeng

    2017-02-01

    In this paper, the attitude stability of liquid-filled spacecraft with flexible appendage is investigated. The motion of liquid sloshing is modeled as the spherical pendulum, and the flexible appendage is approached by a linear shearing beam. Nonlinear dynamic equations of the coupled system are derived from the Hamiltonian. The stability of the coupled system was analyzed by using the energy-Casimir method, and the nonlinear stability theorem of the coupled spacecraft system was also obtained. Through numerical computation, the correctness of the proposed theorem is verified and the boundary curves of the stable region are presented. The increase of the angular velocity and flexible attachment length will weaken the attitude stability, and the change of the filled ratio of liquid fuel tank has a different influence on the stability of the coupled spacecraft, depending on the different conditions. The attitude stability analysis of the coupled spacecraft system in this context is useful for selecting appropriate parameters in the complex spacecraft design.

  9. Breakdown and Partial Discharge Measurements of Some Commonly Used Dielectric Materials in Liquid Nitrogen for HTS Applications

    SciTech Connect

    James, David Randy; Sauers, Isidor; Ellis, Alvin R; Tuncer, Enis; Tekletsadik, Kasegn; Hazelton, Drew

    2007-01-01

    For high temperature superconducting (HTS) power applications it is necessary to improve the understanding of the dielectric properties of materials in a cryogenic environment. It is necessary to know the breakdown strength of materials and systems as a function of gap in order to scale to higher voltages. The partial discharge (PD) onset voltage for materials is also very important since the primary aging mechanism at cryogenic temperature is PD. Another important design characteristic is the surface flashover voltage of a material in liquid nitrogen as a function of gap. With these characteristics in mind, several generic materials were investigated under a variety of electrode and gap configurations. The impulse breakdown voltage and PD onset of three types of commercial polyetherimide, filled and unfilled, were measured at room temperature and 77 K. A modest increase in PD onset voltage was observed at the lower temperature. Breakdown voltages of fiberglass reinforced plastic (FRP) cylinders for two wall thicknesses were measured which showed a decrease in strength at the larger gap. Breakdown voltages for liquid nitrogen using a sphere-plane electrode geometry were measured. Also flashover voltages along a FRP plate immersed in liquid nitrogen were performed for sphere-plane and rod-plane electrodes at 1 bar pressure. It was found that the breakdown voltage increased only slightly with increasing gap lengths.

  10. Electron impact ionization of liquid and gaseous water: a single-center partial-wave approach.

    PubMed

    Champion, C

    2010-01-07

    In this work, we report a unified methodology to express the molecular wavefunctions of water in both vapor and liquid phases by means of a single-center approach. These latter are then used as input data in a theoretical treatment--previously published and successfully tested--for describing the water ionization process in the first Born approximation (Champion et al 2006 Phys. Rev. A 73 012717). The multi-differential and total cross sections also obtained are reported for the two thermodynamical phases investigated and compared to the rare existing experimental and theoretical data.

  11. Injection of liquid carbon dioxide into a reservoir partially saturated with methane hydrate

    NASA Astrophysics Data System (ADS)

    Shagapov, V. Sh.; Khasanov, M. K.; Musakaev, N. R.

    2016-11-01

    A mathematical model is proposed to describe methane-carbon dioxide replacement in gas hydrate by injecting liquid carbon dioxide into a porous medium initially saturated with methane and its hydrate. Self-similar solutions of the axisymmetric problems are constructed that describe the distribution of the main parameters of the reservoir. It is shown that there exist solutions according to which the process can occur both with and without boiling of carbon dioxide. Diagrams of the existence of each type of solution are constructed.

  12. Partial oxidation of vanadium-containing heavy liquid hydrocarbonaceous and solid carbonaceous fuels

    SciTech Connect

    Becker, M.W.; Stevenson, J.S.; Najjar, M.S.

    1987-11-10

    In a partial oxidation process for the production of gaseous mixtures comprising H/sub 2/ + CO in the reaction zone of a down flowing gas generator, this patent describes the improvement comprising: (1) mixing together the following materials to produce a feed mixture, (i) a vanadium-containing fuel; (ii) supplemental iron-containing ash fusion temperature reducing agent containing iron compounds; and (iii) at least a portion of the remainder of the iron-containing slag after separation of the course slag fraction; (2) reacting by partial oxidation the feed mixture with a free-oxygen containing gas in the presence of a temperature moderator in a refractory-lined free-flow unpacked reaction zone of the gas generator the vanadium-containing feed mixture from (1) to produce a hot raw effluent gas stream comprising H/sub 2/ + CO along with vanadium-containing molten slag and particulate matter; (3) passing the hot raw effluent gas stream from (2) at a temperature in the range of about 2200/sup 0/F to 3000/sup 0/F and a pressure in the range of about 1 to 300 atmospheres down through a coaxial discharge passage in the bottom of the reaction zone of the gas generator; (4) passing through the hot effluent gas stream; and (5) passing the water and solids from the bottom of the quench tank into a water-solids separation zone.

  13. Antifatigue Activity of Liquid Cultured Tricholoma matsutake Mycelium Partially via Regulation of Antioxidant Pathway in Mouse

    PubMed Central

    Li, Quan; Wang, Yanzhen; Cai, Guangsheng; Kong, Fange; Wang, Xiaohan; Liu, Yang; Yang, Chuanbin; Wang, Di; Teng, Lirong

    2015-01-01

    Tricholoma matsutake has been popular as food and biopharmaceutical materials in Asian countries for its various pharmacological activities. The present study aims to analyze the antifatigue effects on enhancing exercise performance of Tricholoma matsutake fruit body (ABM) and liquid cultured mycelia (TM) in mouse model. Two-week Tricholoma matsutake treatment significantly enhances the exercise performance in weight-loaded swimming, rotating rod, and forced running test. In TM- and ABM-treated mice, some factors were observed at 60 min after swimming compared with nontreated mice, such as the increased levels of adenosine triphosphate (ATP), antioxidative enzymes, and glycogen and the reduced levels of malondialdehyde and reactive oxygen species in muscle, liver, and/or serum. Further data obtained from western blot show that CM and ABM have strongly enhanced the activation of 5′-AMP-activated protein kinase (AMPK), and the expressions of peroxisome proliferator have activated receptor γ coactivator-1α (PGC-1α) and phosphofructokinase-1 (PFK-1) in liver. Our data suggest that both Tricholoma matsutake fruit body and liquid cultured mycelia possess antifatigue effects related to AMPK-linked antioxidative pathway. The information uncovered in our study may serve as a valuable resource for further identification and provide experimental evidence for clinical trials of Tricholoma matsutake as an effective agent against fatigue related diseases. PMID:26697489

  14. [Mechanical ventilator].

    PubMed

    Kimura, Akio; Hashimoto, S

    2009-07-01

    The development of the computer technology brought reform in the field of medical equipment. Originally the mechanical ventilator was an instrument only as for running by pressure and the tool that let you breathe. However, it has a function to assist a measurement (tidal volume, peek pressure, etc.) and to wean from a ventilator. There is a case to use a mechanical ventilator for after a chest surgical operation. After the operation without the complication, it seems that there is not the special administration. However, special respiratory management is necessary in case of chronic respiratory failure and acute lung injury, acute respiratory distress syndrome. Therefore I introduce a method to use a respirator after an operation in our institution.

  15. The effect of the partial pressure of water vapor on the surface tension of the liquid water-air interface.

    PubMed

    Pérez-Díaz, José L; Álvarez-Valenzuela, Marco A; García-Prada, Juan C

    2012-09-01

    Precise measurements of the surface tension of water in air vs. humidity at 5, 10, 15, and 20 °C are shown. For constant temperature, surface tension decreases linearly for increasing humidity in air. These experimental data are in good agreement with a simple model based on Newton's laws here proposed. It is assumed that evaporating molecules of water are ejected from liquid to gas with a mean normal component of the speed of "ejection" greater than zero. A high humidity in the air reduces the net flow of evaporating water molecules lowering the effective surface tension on the drop. Therefore, just steam in air acts as an effective surfactant for the water-air interface. It can partially substitute chemical surfactants helping to reduce their environmental impact.

  16. Prediction of Arterial Blood pH and Partial Pressure of Carbon dioxide from Venous Blood Samples in Patients Receiving Mechanical Ventilation.

    PubMed

    Tavakol, Kamran; Ghahramanpoori, Bahareh; Fararouei, Mohammad

    2013-07-01

    Substitution of arterial with venous blood samples to estimate blood gas status is highly preferable due to practical and safety concerns. Numerous studies support the substitution of arterial by venous blood samples, reporting strong correlations between arterial and venous values. This study further investigated the predictive ability of venous blood samples for arterial Acid-Base Balance (pH) and pressure of carbon dioxide (pCO2). Participants were 51 post-brain surgery patients receiving mechanical ventilation, who had blood samples taken simultaneously from radial artery of the wrist and elbow vein. Results showed significant associations between arterial and venous pH and pCO2. However, the variation of regression residuals was not homogenous, and the regression line did not fit properly to the data, indicating that simple linear regression is sub-optimal for prediction of arterial pH and pCO2 by venous blood sample. Although highly significant correlations were found between arterial and venous blood pH and pCO2, the results did not support the reliability of prediction of arterial blood pH and pCO2 by venous blood samples across a range of concentrations.

  17. Nasal ventilation.

    PubMed Central

    Simonds, A. K.

    1998-01-01

    Nasal intermittent positive pressure ventilation is likely to have an increasing role in the management of acute ventilatory failure, weaning, and chronic ventilatory problems. Further improvements in ventilator and mask design will be seen. Appropriate application is likely to reduce both mortality and admissions to intensive care, while domiciliary use can improve life expectancy and/or quality of life in chronic ventilatory disorders. As with any new technique, enthusiasm should not outweigh clear outcome information, and possible new indications should always be subject to careful assessment. Images Figure 2 PMID:9799887

  18. [Home mechanical ventilation: Invasive and noninvasive ventilation therapy for chronic respiratory failure].

    PubMed

    Huttmann, S E; Storre, J H; Windisch, W

    2015-06-01

    Home mechanical ventilation represents a valuable therapeutic option to improve alveolar ventilation in patients with chronic respiratory failure. For this purpose both invasive ventilation via tracheostomy and noninvasive ventilation via facemasks are available. The primary goal of home mechanical ventilation is a reduction of symptoms, improvement of quality of life and in many cases reduction of mortality. Elective establishment of home mechanical ventilation is typically provided for noninvasive ventilation in respect to clinical symptoms and partial pressure of carbon dioxide depending on the underlying disease. However, invasive mechanical ventilation is increasingly being used to continue ventilatory support in polymorbid patients following unsuccessful weaning. Recommendations and guidelines have been published by the German Respiratory Society (DGP).

  19. A Brief Period of Hypothermia Induced by Total Liquid Ventilation Decreases End-Organ Damage and Multiorgan Failure Induced by Aortic Cross-Clamping.

    PubMed

    Mongardon, Nicolas; Kohlhauer, Matthias; Lidouren, Fanny; Hauet, Thierry; Giraud, Sébastien; Hutin, Alice; Costes, Bruno; Barau, Caroline; Bruneval, Patrick; Micheau, Philippe; Cariou, Alain; Dhonneur, Gilles; Berdeaux, Alain; Ghaleh, Bijan; Tissier, Renaud

    2016-09-01

    In animal models, whole-body cooling reduces end-organ injury after cardiac arrest and other hypoperfusion states. The benefits of cooling in humans, however, are uncertain, possibly because detrimental effects of prolonged cooling may offset any potential benefit. Total liquid ventilation (TLV) provides both ultrafast cooling and rewarming. In previous reports, ultrafast cooling with TLV potently reduced neurological injury after experimental cardiac arrest in animals. We hypothesized that a brief period of rapid cooling and rewarming via TLV could also mitigate multiorgan failure (MOF) after ischemia-reperfusion induced by aortic cross-clamping. Anesthetized rabbits were submitted to 30 minutes of supraceliac aortic cross-clamping followed by 300 minutes of reperfusion. They were allocated either to a normothermic procedure with conventional ventilation (control group) or to hypothermic TLV (33°C) before, during, and after cross-clamping (pre-clamp, per-clamp, and post-clamp groups, respectively). In all TLV groups, hypothermia was maintained for 75 minutes and switched to a rewarming mode before resumption to conventional mechanical ventilation. End points included cardiovascular, renal, liver, and inflammatory parameters measured 300 minutes after reperfusion. In the normothermic (control) group, ischemia-reperfusion injury produced evidence of MOF including severe vasoplegia, low cardiac output, acute kidney injury, and liver failure. In the TLV group, we observed gradual improvements in cardiac output in post-clamp, per-clamp, and pre-clamp groups versus control (53 ± 8, 64 ± 12, and 90 ± 24 vs 36 ± 23 mL/min/kg after 300 minutes of reperfusion, respectively). Liver biomarker levels were also lower in pre-clamp and per-clamp groups versus control. However, acute kidney injury was prevented in pre-clamp, and to a limited extent in per-clamp groups, but not in the post-clamp group. For instance, creatinine clearance was 4.8 ± 3.1 and 0.5 ± 0.6 m

  20. [Structural characterization of Astragalus polysaccharides using partial acid hydrolysis-hydrophilic interaction liquid chromatography-mass spectrometry].

    PubMed

    Liang, Tu; Fu, Qing; Xin, Huaxia; Li, Fangbing; Jin, Yu; Liang, Xinmiao

    2014-12-01

    Water-soluble polysaccharides from traditional Chinese medicine (TCM) have properties of broad-spectrum treatment and low toxicity, making them as important components in natural medicines and health products. In order to solve the problem of polysaccharides characterization caused by their complex structures, a "bottom-up" approach was developed to complete the characterization of polysaccharides from Astragalus. Firstly, Astragalus pieces were extracted with hot water and then were precipitated by ethanol to obtain Astragalus polysaccharides. Secondly, a partial acid hydrolysis method was carried out and the effects of time, acid concentration and temperature on hydrolysis were investigated. The degree of hydrolysis increased along with the increase of hydrolysis time and acid concentration. The temperature played a great role in the hydrolysis process. No hydrolysis of the polysaccharides occurred at low temperature, while the polysaccharides were almost hydrolyzed to monosaccharide at high temperature. Under the optimum hydrolysis conditions (4 h, 1.5 mol/L trifluoroacetic acid, and 80 °C), Astragalus polysaccharides were hydrolyzed to characteristic oligosaccharide fragments. At last, a hydrophilic liquid chromatography-mass spectrometry method was used for the separation and structural characterization of the polysaccharide hydrolysates. The results showed that the resulting polysaccharides were mainly 1--> 4 linear glucan, and gluco-oligosaccharides with the degrees of polymerization (DP) of 4 - 11 were obtained after partial acid hydrolysis. The significance of this study is that it is the guidance for the characterization of other TCM polysaccharides.

  1. [Modalities of mechanical ventilation].

    PubMed

    Subirana, M; Bazan, P

    2000-01-01

    Mechanical ventilation improves the symptoms and reduces complications of acute respiratory failure. Recent advances in microprocessor technology have increased the sophistication of mechanical ventilators, thus leading to new ventilation modalities. This article describes the ventilation modalities available, grouping them as conventional, alternative and new modalities. Conventional ventilation includes the most widely used modalities, alternative ventilation includes less frequently used modalities, and new ventilation modalities include recently introduced options that are available on the latest-generation mechanical ventilators.

  2. Liquid crystal ordering of DNA and RNA oligomers with partially overlapping sequences

    NASA Astrophysics Data System (ADS)

    Zanchetta, G.; Nakata, M.; Buscaglia, M.; Clark, N. A.; Bellini, T.

    2008-12-01

    We have recently shown that solutions of very short double-stranded B-DNA and A-RNA, down to six base pairs in length, can self-organize into chiral nematic and columnar liquid crystal (LC) phases. These observations were made on fully complementary sequences forming duplexes with blunt ends, where the LC ordering is due to base stacking forces promoting end-to-end aggregation of duplexes into living-polymer-type structures. Here we report LC formation in solutions of DNA and RNA 14mers forming double helices having single-stranded dangling ends that are 'sticky', i.e., mutually complementary with similar ends on other duplexes. This finding widens the conditions for spontaneous long range ordering in oligomeric nucleic acids, thus strengthening the notion that nucleic acids have remarkable self-assembly capability. Quantitative analysis of the phase diagram enables the extraction, within a nearest-neighbor interaction approximation, of the free energy associated with the pairing and stacking of nucleobases.

  3. Ventilator waveforms.

    PubMed

    Mellema, Matthew S

    2013-08-01

    Ventilator waveforms are graphic representations of changes in pressure, flow, and volume within a ventilator circuit. The changes in these parameters over time may be displayed individually (scalars) or plotted one against another (pressure-volume and flow-volume loops). There are 6 basic shapes of scalar waveforms, but only 3 are functionally distinct (square, ramp, and sine). The pressure scalar is a particularly valuable tool when constant flow (e.g., volume control) modes are employed and an inspiratory pause is added. In this setting, inspection of the pressure waveform can allow determination of static, quasistatic, and dynamic compliance, as well as relative changes in airway resistance. Inspection of the pressure waveform can also help to identify many important aspects of patient drug responses, dyssynchrony, and air trapping (auto positive end-expiratory pressure [auto-PEEP]). Depending on the ventilation mode employed, the shape of the flow waveform may be set by the ventilator operator or may be dependent on patient effort and lung mechanics. Decelerating flow patterns have several important advantages when this option is available. Inspection of flow waveforms is crucial in the recognition of dyssynchrony, setting optimal inspiratory times, evaluating responses to bronchodilators, and the recognition of auto-PEEP. The volume waveform often contains somewhat less useful information than the other 2 scalars, but plays a crucial role in the identification of leaks in the circuit. Pressure-volume loops are particularly useful in setting PEEP and peak inspiratory pressure ranges. Inspection of these loops also often helps in the evaluation of lung mechanics, in the identification of circuit leaks, and in the assessment of patient triggering effort. Flow-volume loops are extremely useful in the identification of leaks and excessive airway secretions as well as alterations in airway resistance. Lastly, serial waveform inspection is crucial to the

  4. Partially oxidized atomic cobalt layers for carbon dioxide electroreduction to liquid fuel

    NASA Astrophysics Data System (ADS)

    Gao, Shan; Lin, Yue; Jiao, Xingchen; Sun, Yongfu; Luo, Qiquan; Zhang, Wenhua; Li, Dianqi; Yang, Jinlong; Xie, Yi

    2016-01-01

    Electroreduction of CO2 into useful fuels, especially if driven by renewable energy, represents a potentially ‘clean’ strategy for replacing fossil feedstocks and dealing with increasing CO2 emissions and their adverse effects on climate. The critical bottleneck lies in activating CO2 into the CO2•- radical anion or other intermediates that can be converted further, as the activation usually requires impractically high overpotentials. Recently, electrocatalysts based on oxide-derived metal nanostructures have been shown to enable CO2 reduction at low overpotentials. However, it remains unclear how the electrocatalytic activity of these metals is influenced by their native oxides, mainly because microstructural features such as interfaces and defects influence CO2 reduction activity yet are difficult to control. To evaluate the role of the two different catalytic sites, here we fabricate two kinds of four-atom-thick layers: pure cobalt metal, and co-existing domains of cobalt metal and cobalt oxide. Cobalt mainly produces formate (HCOO-) during CO2 electroreduction; we find that surface cobalt atoms of the atomically thin layers have higher intrinsic activity and selectivity towards formate production, at lower overpotentials, than do surface cobalt atoms on bulk samples. Partial oxidation of the atomic layers further increases their intrinsic activity, allowing us to realize stable current densities of about 10 milliamperes per square centimetre over 40 hours, with approximately 90 per cent formate selectivity at an overpotential of only 0.24 volts, which outperforms previously reported metal or metal oxide electrodes evaluated under comparable conditions. The correct morphology and oxidation state can thus transform a material from one considered nearly non-catalytic for the CO2 electroreduction reaction into an active catalyst. These findings point to new opportunities for manipulating and improving the CO2 electroreduction properties of metal systems

  5. Spatial reorientation experiments for NMR of solids and partially oriented liquids.

    PubMed

    Martin, Rachel W; Kelly, John E; Collier, Kelsey A

    2015-11-01

    Motional reorientation experiments are extensions of Magic Angle Spinning (MAS) where the rotor axis is changed in order to average out, reintroduce, or scale anisotropic interactions (e.g. dipolar couplings, quadrupolar interactions or chemical shift anisotropies). This review focuses on Variable Angle Spinning (VAS), Switched Angle Spinning (SAS), and Dynamic Angle Spinning (DAS), all of which involve spinning at two or more different angles sequentially, either in successive experiments or during a multidimensional experiment. In all of these experiments, anisotropic terms in the Hamiltonian are scaled by changing the orientation of the spinning sample relative to the static magnetic field. These experiments vary in experimental complexity and instrumentation requirements. In VAS, many one-dimensional spectra are collected as a function of spinning angle. In SAS, dipolar couplings and/or chemical shift anisotropies are reintroduced by switching the sample between two different angles, often 0° or 90° and the magic angle, yielding a two-dimensional isotropic-anisotropic correlation spectrum. Dynamic Angle Spinning (DAS) is a related experiment that is used to simultaneously average out the first- and second-order quadrupolar interactions, which cannot be accomplished by spinning at any unique rotor angle in physical space. Although motional reorientation experiments generally require specialized instrumentation and data analysis schemes, some are accessible with only minor modification of standard MAS probes. In this review, the mechanics of each type of experiment are described, with representative examples. Current and historical probe and coil designs are discussed from the standpoint of how each one accomplishes the particular objectives of the experiment(s) it was designed to perform. Finally, applications to inorganic materials and liquid crystals, which present very different experimental challenges, are discussed. The review concludes with perspectives

  6. Ultrafast and whole-body cooling with total liquid ventilation induces favorable neurological and cardiac outcomes after cardiac arrest in rabbits.

    PubMed

    Chenoune, M; Lidouren, F; Adam, C; Pons, S; Darbera, L; Bruneval, P; Ghaleh, B; Zini, R; Dubois-Randé, J-L; Carli, P; Vivien, B; Ricard, J-D; Berdeaux, A; Tissier, R

    2011-08-23

    In animal models of cardiac arrest, the benefit afforded by hypothermia is closely linked to the rapidity of the decrease in body temperature after resuscitation. Because total liquid ventilation (TLV) with temperature-controlled perfluorocarbons induces a very rapid and generalized cooling, we aimed to determine whether this could limit the post-cardiac arrest syndrome in a rabbit model. We especially focused on neurological, cardiac, pulmonary, liver and kidney dysfunctions. Anesthetized rabbits were submitted to either 5 or 10 minutes of untreated ventricular fibrillation. After cardiopulmonary resuscitation and resumption of a spontaneous circulation, the animals underwent either normothermic life support (control) or therapeutic hypothermia induced by TLV. The latter procedure decreased esophageal and tympanic temperatures to 32°C to 33°C within only 10 minutes. After rewarming, the animals submitted to TLV exhibited an attenuated neurological dysfunction and decreased mortality 7 days later compared with control. The neuroprotective effect of TLV was confirmed by a significant reduction in brain histological damages. We also observed limitation of myocardial necrosis, along with a decrease in troponin I release and a reduced myocardial caspase 3 activity, with TLV. The beneficial effects of TLV were directly related to the rapidity of hypothermia induction because neither conventional cooling (cold saline infusion plus external cooling) nor normothermic TLV elicited a similar protection. Ultrafast cooling instituted by TLV exerts potent neurological and cardiac protection in an experimental model of cardiac arrest in rabbits. This could be a relevant approach to provide a global and protective hypothermia against the post-cardiac arrest syndrome.

  7. 46 CFR 153.316 - Special cargo pumproom ventilation rate.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Special cargo pumproom ventilation rate. 153.316 Section... CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Handling Space Ventilation § 153.316 Special cargo pumproom ventilation rate. When Table...

  8. 46 CFR 153.316 - Special cargo pumproom ventilation rate.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Special cargo pumproom ventilation rate. 153.316 Section... CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Handling Space Ventilation § 153.316 Special cargo pumproom ventilation rate. When Table...

  9. 46 CFR 153.310 - Ventilation system type.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Ventilation system type. 153.310 Section 153.310... CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Handling Space Ventilation § 153.310 Ventilation system type. A cargo handling space must have a...

  10. 46 CFR 153.316 - Special cargo pumproom ventilation rate.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Special cargo pumproom ventilation rate. 153.316 Section... CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Handling Space Ventilation § 153.316 Special cargo pumproom ventilation rate. When Table...

  11. 46 CFR 153.316 - Special cargo pumproom ventilation rate.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Special cargo pumproom ventilation rate. 153.316 Section... CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Handling Space Ventilation § 153.316 Special cargo pumproom ventilation rate. When Table...

  12. 46 CFR 153.316 - Special cargo pumproom ventilation rate.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Special cargo pumproom ventilation rate. 153.316 Section... CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Handling Space Ventilation § 153.316 Special cargo pumproom ventilation rate. When Table...

  13. 46 CFR 153.310 - Ventilation system type.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Ventilation system type. 153.310 Section 153.310... CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Handling Space Ventilation § 153.310 Ventilation system type. A cargo handling space must have a...

  14. 46 CFR 153.310 - Ventilation system type.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Ventilation system type. 153.310 Section 153.310... CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Handling Space Ventilation § 153.310 Ventilation system type. A cargo handling space must have a...

  15. 46 CFR 153.310 - Ventilation system type.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Ventilation system type. 153.310 Section 153.310... CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Handling Space Ventilation § 153.310 Ventilation system type. A cargo handling space must have a...

  16. 46 CFR 153.312 - Ventilation system standards.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Ventilation system standards. 153.312 Section 153.312... CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Handling Space Ventilation § 153.312 Ventilation system standards. A cargo handling space...

  17. 46 CFR 153.312 - Ventilation system standards.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Ventilation system standards. 153.312 Section 153.312... CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Handling Space Ventilation § 153.312 Ventilation system standards. A cargo handling space...

  18. Comparison between Total Parenteral Nutrition Vs. Partial Parenteral Nutrition on Serum Lipids Among Chronic Ventilator Dependent Patients; A Multi Center Study

    PubMed Central

    Radpay, Rojan; Radpay, Badiozaman

    2016-01-01

    Background: Malnutrition is very common among chronically hospitalized patients, especially those in the intensive care unit (ICU). Identifying the patients at risk and providing suitable nutritional support can prevent and/or overcome malnutrition in them. Total parenteral nutrition (TPN) and partial parenteral nutrition (PPN) are two common routes to deliver nutrition to hospitalized patients. We conducted a multicenter, prospective double blind randomized controlled trial to evaluate the benefits and compare their adverse effects of each method. Materials and Methods: 97 patients were enrolled and divided into two groups based on the inclusion criteria. Serum protein, serum albumin, serum transferrin, and total lymphocyte count were measured on days 7 and 14. Results: We did not find any statistically significant differences in clinical status or laboratory values between the two groups but there were significant improvements in measured lab values between days 7 and 14 (p<0.005) indicating improved nutritional status in each groups. Conclusion: This study shows that both TPN and PPN can be used safely in chronic ICU patients to provide nutritional support and prevent catabolic state among chronic critically ill patients. We need to develop precise selection criteria in order to choose the patients who would benefit the most from TPN and PPN. In addition, appropriate laboratory markers are needed to monitor the metabolic requirements of the patients and assess their progress. PMID:27403176

  19. Molecular orientation distributions during injection molding of liquid crystalline polymers: Ex situ investigation of partially filled moldings

    SciTech Connect

    Fang, Jun; Burghardt, Wesley R.; Bubeck, Robert A.

    2013-01-10

    The development of molecular orientation in thermotropic liquid crystalline polymers (TLCPs) during injection molding has been investigated using two-dimensional wide-angle X-ray scattering coordinated with numerical computations employing the Larson-Doi polydomain model. Orientation distributions were measured in 'short shot' moldings to characterize structural evolution prior to completion of mold filling, in both thin and thick rectangular plaques. Distinct orientation patterns are observed near the filling front. In particular, strong extension at the melt front results in nearly transverse molecular alignment. Far away from the flow front shear competes with extension to produce complex spatial distributions of orientation. The relative influence of shear is stronger in the thin plaque, producing orientation along the filling direction. Exploiting an analogy between the Larson-Doi model and a fiber orientation model, we test the ability of process simulation tools to predict TLCP orientation distributions during molding. Substantial discrepancies between model predictions and experimental measurements are found near the flow front in partially filled short shots, attributed to the limits of the Hele-Shaw approximation used in the computations. Much of the flow front effect is however 'washed out' by subsequent shear flow as mold filling progresses, leading to improved agreement between experiment and corresponding numerical predictions.

  20. Preliminary drop-tower experiments on liquid-interface geometry in partially filled containers at zero gravity

    NASA Technical Reports Server (NTRS)

    Smedley, G.

    1990-01-01

    Plexiglass containers with rounded trapezoidal cross sections were designed and built to test the validity of Concus and Finn's existence theorem (1974, 1983) for a bounded free liquid surface at zero gravity. Experiments were carried out at the NASA Lewis two-second drop tower. Dyed ethanol-water solutions and three immiscible liquid pairs, with one liquid dyed, were tested. High-speed movies were used to record the liquid motion. Liquid rose to the top of the smaller end of the containers when the contact angle was small enough, in agreement with the theory. Liquid interface motion demonstrated a strong dependence on physical properties, including surface roughness and contamination.

  1. Laboratory investigation of flux reduction from dense non-aqueous phase liquid (DNAPL) partial source zone remediation by enhanced dissolution

    NASA Astrophysics Data System (ADS)

    Kaye, Andrew J.; Cho, Jaehyun; Basu, Nandita B.; Chen, Xiaosong; Annable, Michael D.; Jawitz, James W.

    2008-11-01

    This study investigated the benefits of partial removal of dense nonaqueous phase liquid (DNAPL) source zones using enhanced dissolution in eight laboratory scale experiments. The benefits were assessed by characterizing the relationship between reductions in DNAPL mass and the corresponding reduction in contaminant mass flux. Four flushing agents were evaluated in eight controlled laboratory experiments to examine the effects of displacement fluid property contrasts and associated override and underride on contaminant flux reduction ( Rj) vs. mass reduction ( Rm) relationships ( Rj( Rm)): 1) 50% ethanol/50% water (less dense than water), 2) 40% ethyl-lactate/60% water (more dense than water), 3) 18% ethanol/26% ethyl-lactate/56% water (neutrally buoyant), and 4) 2% Tween-80 surfactant (also neutrally buoyant). For each DNAPL architecture evaluated, replicate experiments were conducted where source zone dissolution was conducted with a single flushing event to remove most of the DNAPL from the system, and with multiple shorter-duration floods to determine the path of the Rj( Rm) relationship. All of the single-flushing experiments exhibited similar Rj( Rm) relationships indicating that override and underride effects associated with cosolvents did not significantly affect the remediation performance of the agents. The Rj( Rm) relationship of the multiple injection experiments for the cosolvents with a density contrast with water tended to be less desirable in the sense that there was less Rj for a given Rm. UTCHEM simulations supported the observations from the laboratory experiments and demonstrated the capability of this model to predict Rj( Rm) relationships for non-uniformly distributed NAPL sources.

  2. Ventilation heterogeneity in obesity.

    PubMed

    Pellegrino, Riccardo; Gobbi, Alessandro; Antonelli, Andrea; Torchio, Roberto; Gulotta, Carlo; Pellegrino, Giulia Michela; Dellacà, Raffaele; Hyatt, Robert E; Brusasco, Vito

    2014-05-01

    Obesity is associated with important decrements in lung volumes. Despite this, ventilation remains normally or near normally distributed at least for moderate decrements in functional residual capacity (FRC). We tested the hypothesis that this is because maximum flow increases presumably as a result of an increased lung elastic recoil. Forced expiratory flows corrected for thoracic gas compression volume, lung volumes, and forced oscillation technique at 5-11-19 Hz were measured in 133 healthy subjects with a body mass index (BMI) ranging from 18 to 50 kg/m(2). Short-term temporal variability of ventilation heterogeneity was estimated from the interquartile range of the frequency distribution of the difference in inspiratory resistance between 5 and 19 Hz (R5-19_IQR). FRC % predicted negatively correlated with BMI (r = -0.72, P < 0.001) and with an increase in slope of either maximal (r = -0.34, P < 0.01) or partial flow-volume curves (r = -0.30, P < 0.01). Together with a slight decrease in residual volume, this suggests an increased lung elastic recoil. Regression analysis of R5-19_IQR against FRC % predicted and expiratory reserve volume (ERV) yielded significantly higher correlation coefficients by nonlinear than linear fitting models (r(2) = 0.40 vs. 0.30 for FRC % predicted and r(2) = 0.28 vs. 0.19 for ERV). In conclusion, temporal variability of ventilation heterogeneities increases in obesity only when FRC falls approximately below 65% of predicted or ERV below 0.6 liters. Above these thresholds distribution is quite well preserved presumably as a result of an increase in lung recoil.

  3. VENTILATION NEEDS DURING CONSTRUCTION

    SciTech Connect

    C.R. Gorrell

    1998-07-23

    The purpose of this analysis is to determine ventilation needs during construction and development of the subsurface repository and develop systems to satisfy those needs. For this analysis, construction is defined as pre-emplacement excavation and development is excavation that takes place simultaneously with emplacement. The three options presented in the ''Overall Development and Emplacement Ventilation Systems'' analysis (Reference 5.5) for development ventilation will be applied to construction ventilation in this analysis as well as adding new and updated ventilation factors to each option for both construction and development. The objective of this analysis is to develop a preferred ventilation system to support License Application Design. The scope of this analysis includes: (1) Description of ventilation conditions; (2) Ventilation factors (fire hazards, dust control, construction logistics, and monitoring and control systems); (3) Local ventilation alternatives; (4) Global ventilation options; and (5) Evaluation of options.

  4. Variable mechanical ventilation

    PubMed Central

    Fontela, Paula Caitano; Prestes, Renata Bernardy; Forgiarini Jr., Luiz Alberto; Friedman, Gilberto

    2017-01-01

    Objective To review the literature on the use of variable mechanical ventilation and the main outcomes of this technique. Methods Search, selection, and analysis of all original articles on variable ventilation, without restriction on the period of publication and language, available in the electronic databases LILACS, MEDLINE®, and PubMed, by searching the terms "variable ventilation" OR "noisy ventilation" OR "biologically variable ventilation". Results A total of 36 studies were selected. Of these, 24 were original studies, including 21 experimental studies and three clinical studies. Conclusion Several experimental studies reported the beneficial effects of distinct variable ventilation strategies on lung function using different models of lung injury and healthy lungs. Variable ventilation seems to be a viable strategy for improving gas exchange and respiratory mechanics and preventing lung injury associated with mechanical ventilation. However, further clinical studies are necessary to assess the potential of variable ventilation strategies for the clinical improvement of patients undergoing mechanical ventilation. PMID:28444076

  5. Variable mechanical ventilation.

    PubMed

    Fontela, Paula Caitano; Prestes, Renata Bernardy; Forgiarini, Luiz Alberto; Friedman, Gilberto

    2017-01-01

    To review the literature on the use of variable mechanical ventilation and the main outcomes of this technique. Search, selection, and analysis of all original articles on variable ventilation, without restriction on the period of publication and language, available in the electronic databases LILACS, MEDLINE®, and PubMed, by searching the terms "variable ventilation" OR "noisy ventilation" OR "biologically variable ventilation". A total of 36 studies were selected. Of these, 24 were original studies, including 21 experimental studies and three clinical studies. Several experimental studies reported the beneficial effects of distinct variable ventilation strategies on lung function using different models of lung injury and healthy lungs. Variable ventilation seems to be a viable strategy for improving gas exchange and respiratory mechanics and preventing lung injury associated with mechanical ventilation. However, further clinical studies are necessary to assess the potential of variable ventilation strategies for the clinical improvement of patients undergoing mechanical ventilation.

  6. SY Tank Farm ventilation isolation option risk assessment report

    SciTech Connect

    Powers, T.B.; Morales, S.D.

    1994-03-01

    The safety of the 241-SY Tank Farm ventilation system has been under extensive scrutiny due to safety concerns associated with tank 101-SY. Hydrogen and other gases are generated and trapped in the waste below the liquid surface. Periodically, these gases are released into the dome space and vented through the exhaust system. This attention to the ventilation system has resulted in the development of several alternative ventilation system designs. The ventilation system provides the primary means of mitigation of accidents associated with flammable gases. This report provides an assessment of various alternatives ventilation system designs.

  7. Analysis of the Pressure Rise in a Partially Filled Liquid Tank in Microgravity with Low Wall Heat Flux and Simultaneous Boiling and Condensation

    NASA Technical Reports Server (NTRS)

    Hasan, Mohammad M.; Balasubramaniam, R.

    2012-01-01

    Experiments performed with Freon 113 in the space shuttle have shown that in a pro- cess of very slow heating, high liquid superheats can be sustained for a long period in microgravity. In a closed system explosive vaporization of superheated liquid resulted in pressure spikes of varying magnitudes. In this paper, we analyze the pressure rise in a partially lled closed tank in which a large vapor bubble (i.e., ullage) is initially present, and the liquid is subjected to a low wall heat ux. The liquid layer adjacent to the wall becomes superheated until the temperature for nucleation of the bubbles (or the incipience of boiling) is achieved. In the absence of the gravity-induced convection large quantities of superheated liquid can accumulate over time near the heated surface. Once the incipience temperature is attained, explosive boiling occurs and the vapor bubbles that are produced on the heater surface tend to quickly raise the tank pressure. The liquid-vapor saturation temperature increases as well. These two e ects tend to induce condensation of the large ullage bubble that is initially present, and tends to mitigate the tank pressure rise. As a result, the tank pressure is predicted to rise sharply, attain a maximum, and subsequently decay slowly. The predicted pressure rise is compared with experimental results obtained in the microgravity environments of the space shuttle for Freon 113. The analysis is appli- cable, in general to heating of liquid in closed containers in microgravity and to cryogenic fuel tanks, in particular where small heat leaks into the tank are unavoidable.

  8. Mechanics of liquid helium in a partially filled rotating dewar in low gravity with application to Gravity Probe-B

    NASA Technical Reports Server (NTRS)

    Schafer, C. F.; Lowry, S. A.

    1983-01-01

    The Gravity Probe-B spacecraft is composed largely of a liquid helium dewar containing an experiment package. It is shown that an unsymmetric liquid helium distribution in the dewar can cause unacceptably high forces, gravitational and gravity gradient forces, at the experiment location. It is further shown that for the planned spacecraft configuration and operational parameters, it is very likely that the liquid helium distribution in the dewar will be unsymmetric. The required symmetry can be attained by using higher operational spacecraft rotation rates.

  9. Analysis of axisymmetrical vibration of a partially liquid-filled elastic sphere by the method of Green's function. [with application to launch vehicle propellant tanks

    NASA Technical Reports Server (NTRS)

    Glaser, R. F.

    1973-01-01

    The longitudinal dynamic behavior of launch vehicles is largely determined by their huge liquid propellant masses which are spring supported by the elastic tank walls. Throughout much of the powered flight time, these masses constitute a high percentage of the entire vehicle mass and, therefore, may dominate the fundamental modes of the vehicle. In this report, a spherical container is considered. The analysis is based on a Galerkin approach, in the course of which a second-order differential equation must be solved. The solution has been obtained by the method of Green's function. This method is favorable because it displays the manner in which the analysis can be extended to partially liquid-filled general shells of revolution. The computer programs currently available for partially liquid-filled propellant tanks are based on the finite element methods and result in analytical models having as many as several hundred degrees of freedom. The method applied in this report results in a model having less than 10 degrees of freedom as can be shown by numerical evaluation. Therefore, it will be possible to analyze propellant tanks using much less computer time with comparable accuracy.

  10. On the validity of a Fickian diffusion model for the spreading of liquid infiltration plumes in partially saturated heterogeneous media

    SciTech Connect

    Pruess, K.

    1994-01-01

    Localized infiltration of aqueous and -non-aqueous phase liquids (NAPLs) occurs in many circumstances. Examples include leaky underground pipelines and storage tanks, landfill and disposal sites, and surface spills. Because of ever-present heterogeneities on different scales such infiltration plumes are expected to disperse transversally and longitudinally. This paper examines recent suggestions that liquid plumes are being dispersed from medium heterogeneities in a manner that is analogous to Fickian diffusion. Numerical simulation experiments on liquid infiltration in heterogeneous media are performed to study the dispersive effects of small-scale heterogeneity. It is found that plume spreading indeed tends to be diffusive. Our results suggest that, as far as infiltration of liquids is concerned, broad classes of heterogeneous media behave as dispersive media with locally homogeneous (albeit anisotropic) permeability.

  11. The Partial Molar Volume and Thermal Expansivity of Fe2O3 in Alkali Silicate Liquids: Evidence for the Average Coordination of Fe3+

    NASA Astrophysics Data System (ADS)

    Liu, Q.; Lange, R.

    2003-12-01

    Ferric iron is an important component in magmatic liquids, especially in those formed at subduction zones. Although it has long been known that Fe3+ occurs in four-, five- and six-fold coordination in crystalline compounds, only recently have all three Fe3+ coordination sites been confirmed in silicate glasses utilizing XANES spectroscopy at the Fe K-edge (Farges et al., 2003). Because the density of a magmatic liquid is largely determined by the geometrical packing of its network-forming cations (e.g., Si4+, Al3+, Ti4+, and Fe3+), the capacity of Fe3+ to undergo composition-induced coordination change affects the partial molar volume of the Fe2O3 component, which must be known to calculate how the ferric-ferrous ratio in magmatic liquids changes with pressure. Previous work has shown that the partial molar volume of Fe2O3 (VFe2O3) varies between calcic vs. sodic silicate melts (Mo et al., 1982; Dingwell and Brearley, 1988; Dingwell et al., 1988). The purpose of this study is to extend the data set in order to search for systematic variations in VFe2O3 with melt composition. High temperature (867-1534° C) density measurements were performed on eleven liquids in the Na2O-Fe2O3-FeO-SiO2 (NFS) system and five liquids in the K2O-Fe2O3-FeO-SiO2 (KFS) system using Pt double-bob Archimedean method. The ferric-ferrous ratio in the sodic and potassic liquids at each temperature of density measurement were calculated from the experimentally calibrated models of Lange and Carmichael (1989) and Tangeman et al. (2001) respectively. Compositions range (in mol%) from 4-18 Fe2O3, 0-3 FeO, 12-39 Na2O, 25-37 K2O, and 43-78 SiO2. Our density data are consistent with those of Dingwell et al. (1988) on similar sodic liquids. Our results indicate that for all five KFS liquids and for eight of eleven NFS liquids, the partial molar volume of the Fe2O3 component is a constant (41.57 ñ 0.14 cm3/mol) and exhibits zero thermal expansivity (similar to that for the SiO2 component). This value

  12. Liquid and surfactant delivery into pulmonary airways

    PubMed Central

    Halpern, David; Fujioka, Hideki; Takayama, Shuichi; Grotberg, James B.

    2008-01-01

    We describe the mechanisms by which liquids and surfactants can be delivered into the pulmonary airways. These are instilled and transported throughout the lung in clinical therapies such as surfactant replacement therapy, partial liquid ventilation and drug delivery. The success of these treatments is contingent on the liquid distribution and the delivery to targeted regions of the lung. The targeting of a liquid plug can be influenced by a variety of factors such as the physical properties of the liquid, the interfacial activity, the gravitational orientation, instillation method and propagation speed. We provide a review of experimental and theoretical studies that examine these effects in single tubes or channels, in tubes with single bifurcations and in the whole lung. PMID:18585985

  13. A flowing liquid test system for assessing the linearity and time-response of rapid fibre optic oxygen partial pressure sensors.

    PubMed

    Chen, R; Hahn, C E W; Farmery, A D

    2012-08-15

    The development of a methodology for testing the time response, linearity and performance characteristics of ultra fast fibre optic oxygen sensors in the liquid phase is presented. Two standard medical paediatric oxygenators are arranged to provide two independent extracorporeal circuits. Flow from either circuit can be diverted over the sensor under test by means of a system of rapid cross-over solenoid valves exposing the sensor to an abrupt change in oxygen partial pressure, P O2. The system is also capable of testing the oxygen sensor responses to changes in temperature, carbon dioxide partial pressure P CO2 and pH in situ. Results are presented for a miniature fibre optic oxygen sensor constructed in-house with a response time ≈ 50 ms and a commercial fibre optic sensor (Ocean Optics Foxy), when tested in flowing saline and stored blood.

  14. Control of Partial Coalescence of Self-Assembled Metal Nano-Particles across Lyotropic Liquid Crystals Templates towards Long Range Meso-Porous Metal Frameworks Design

    PubMed Central

    Dumée, Ludovic F.; Lemoine, Jean-Baptiste; Ancel, Alice; Hameed, Nishar; He, Li; Kong, Lingxue

    2015-01-01

    The formation of purely metallic meso-porous metal thin films by partial interface coalescence of self-assembled metal nano-particles across aqueous solutions of Pluronics triblock lyotropic liquid crystals is demonstrated for the first time. Small angle X-ray scattering was used to study the influence of the thin film composition and processing conditions on the ordered structures. The structural characteristics of the meso-structures formed demonstrated to primarily rely on the lyotropic liquid crystal properties while the nature of the metal nano-particles used as well as the their diameters were found to affect the ordered structure formation. The impact of the annealing temperature on the nano-particle coalescence and efficiency at removing the templating lyotropic liquid crystals was also analysed. It is demonstrated that the lyotropic liquid crystal is rendered slightly less thermally stable, upon mixing with metal nano-particles and that low annealing temperatures are sufficient to form purely metallic frameworks with average pore size distributions smaller than 500 nm and porosity around 45% with potential application in sensing, catalysis, nanoscale heat exchange, and molecular separation. PMID:28347094

  15. Home Ventilator Guide

    MedlinePlus

    ... are for negative pressure ventilators currently on the markets. There is no “standard” form for specifications. American ... specifications are for bilevel ventilators currently on the markets. There is no “standard” form for specifications. American ...

  16. VENTILATION MODEL REPORT

    SciTech Connect

    V. Chipman

    2002-10-31

    The purpose of the Ventilation Model is to simulate the heat transfer processes in and around waste emplacement drifts during periods of forced ventilation. The model evaluates the effects of emplacement drift ventilation on the thermal conditions in the emplacement drifts and surrounding rock mass, and calculates the heat removal by ventilation as a measure of the viability of ventilation to delay the onset of peak repository temperature and reduce its magnitude. The heat removal by ventilation is temporally and spatially dependent, and is expressed as the fraction of heat carried away by the ventilation air compared to the fraction of heat produced by radionuclide decay. One minus the heat removal is called the wall heat fraction, or the remaining amount of heat that is transferred via conduction to the surrounding rock mass. Downstream models, such as the ''Multiscale Thermohydrologic Model'' (BSC 2001), use the wall heat fractions as outputted from the Ventilation Model to initialize their postclosure analyses.

  17. VENTILATION TECHNOLOGY SYSTEMS ANALYSIS

    EPA Science Inventory

    The report gives results of a project to develop a systems analysis of ventilation technology and provide a state-of-the-art assessment of ventilation and indoor air quality (IAQ) research needs. (NOTE: Ventilation technology is defined as the hardware necessary to bring outdoor ...

  18. VENTILATION TECHNOLOGY SYSTEMS ANALYSIS

    EPA Science Inventory

    The report gives results of a project to develop a systems analysis of ventilation technology and provide a state-of-the-art assessment of ventilation and indoor air quality (IAQ) research needs. (NOTE: Ventilation technology is defined as the hardware necessary to bring outdoor ...

  19. Selective partial hydrogenation of alkynes to (Z)-alkenes with ionic liquid-doped nickel nanocatalysts at near ambient conditions.

    PubMed

    Konnerth, Hannelore; Prechtl, Martin H G

    2016-07-12

    A selective hydrogenation method for forming (Z)-alkenes from alkynes has been developed using a catalyst system of cheap Ni-NPs in a nitrile functionalised imidazolium based ionic liquid (IL) operating under very mild reaction conditions of 30-50 °C and 1-4 bar H2 pressure.

  20. DEMAND CONTROLLED VENTILATION AND CLASSROOM VENTILATION

    SciTech Connect

    Fisk, William J.; Mendell, Mark J.; Davies, Molly; Eliseeva, Ekaterina; Faulkner, David; Hong, Tienzen; Sullivan, Douglas P.

    2014-01-06

    This document summarizes a research effort on demand controlled ventilation and classroom ventilation. The research on demand controlled ventilation included field studies and building energy modeling. Major findings included: ? The single-location carbon dioxide sensors widely used for demand controlled ventilation frequently have large errors and will fail to effectively control ventilation rates (VRs).? Multi-location carbon dioxide measurement systems with more expensive sensors connected to multi-location sampling systems may measure carbon dioxide more accurately.? Currently-available optical people counting systems work well much of the time but have large counting errors in some situations. ? In meeting rooms, measurements of carbon dioxide at return-air grilles appear to be a better choice than wall-mounted sensors.? In California, demand controlled ventilation in general office spaces is projected to save significant energy and be cost effective only if typical VRs without demand controlled ventilation are very high relative to VRs in codes. Based on the research, several recommendations were developed for demand controlled ventilation specifications in the California Title 24 Building Energy Efficiency Standards.The research on classroom ventilation collected data over two years on California elementary school classrooms to investigate associations between VRs and student illness absence (IA). Major findings included: ? Median classroom VRs in all studied climate zones were below the California guideline, and 40percent lower in portable than permanent buildings.? Overall, one additional L/s per person of VR was associated with 1.6percent less IA. ? Increasing average VRs in California K-12 classrooms from the current average to the required level is estimated to decrease IA by 3.4percent, increasing State attendance-based funding to school districts by $33M, with $6.2 M in increased energy costs. Further VR increases would provide additional benefits

  1. Hydrothermal carbonization (HTC): near infrared spectroscopy and partial least-squares regression for determination of selective components in HTC solid and liquid products derived from maize silage.

    PubMed

    Reza, M Toufiq; Becker, Wolfgang; Sachsenheimer, Kerstin; Mumme, Jan

    2014-06-01

    Near-infrared (NIR) spectroscopy was evaluated as a rapid method of predicting fiber components (hemicellulose, cellulose, lignin, and ash) and selective compounds of hydrochar and corresponding process liquor produced by hydrothermal carbonization (HTC) of maize silage. Several HTC reaction times and temperatures were applied and NIR spectra of both HTC solids and liquids were obtained and correlated with concentration determined from van-Soest fiber analysis, IC, and UHPLC. Partial least-squares regression was applied to calculate models for the prediction of selective substances. The model developed with the spectra had the best performance in 3-7 factors with a correlation coefficient, which varied between 0.9275-0.9880 and 0.9364-0.9957 for compounds in solid and liquid, respectively. Calculated root mean square errors of prediction (RMSEP) were 0.42-5.06mg/kg. The preliminary results indicate that NIR, a widely applied technique, might be applied to determine chemical compounds in HTC solid and liquid.

  2. 46 CFR 153.314 - Ventilation of spaces not usually occupied.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Ventilation of spaces not usually occupied. 153.314... CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Handling Space Ventilation § 153.314 Ventilation of spaces not usually occupied. (a)...

  3. 46 CFR 153.314 - Ventilation of spaces not usually occupied.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Ventilation of spaces not usually occupied. 153.314... CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Handling Space Ventilation § 153.314 Ventilation of spaces not usually occupied. (a)...

  4. 46 CFR 153.314 - Ventilation of spaces not usually occupied.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Ventilation of spaces not usually occupied. 153.314... CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Handling Space Ventilation § 153.314 Ventilation of spaces not usually occupied. (a)...

  5. Ventilation Model Report

    SciTech Connect

    V. Chipman; J. Case

    2002-12-20

    The purpose of the Ventilation Model is to simulate the heat transfer processes in and around waste emplacement drifts during periods of forced ventilation. The model evaluates the effects of emplacement drift ventilation on the thermal conditions in the emplacement drifts and surrounding rock mass, and calculates the heat removal by ventilation as a measure of the viability of ventilation to delay the onset of peak repository temperature and reduce its magnitude. The heat removal by ventilation is temporally and spatially dependent, and is expressed as the fraction of heat carried away by the ventilation air compared to the fraction of heat produced by radionuclide decay. One minus the heat removal is called the wall heat fraction, or the remaining amount of heat that is transferred via conduction to the surrounding rock mass. Downstream models, such as the ''Multiscale Thermohydrologic Model'' (BSC 2001), use the wall heat fractions as outputted from the Ventilation Model to initialize their post-closure analyses. The Ventilation Model report was initially developed to analyze the effects of preclosure continuous ventilation in the Engineered Barrier System (EBS) emplacement drifts, and to provide heat removal data to support EBS design. Revision 00 of the Ventilation Model included documentation of the modeling results from the ANSYS-based heat transfer model. Revision 01 ICN 01 included the results of the unqualified software code MULTIFLUX to assess the influence of moisture on the ventilation efficiency. The purposes of Revision 02 of the Ventilation Model are: (1) To validate the conceptual model for preclosure ventilation of emplacement drifts and verify its numerical application in accordance with new procedural requirements as outlined in AP-SIII-10Q, Models (Section 7.0). (2) To satisfy technical issues posed in KTI agreement RDTME 3.14 (Reamer and Williams 2001a). Specifically to demonstrate, with respect to the ANSYS ventilation model, the adequacy of

  6. New generation ventilators.

    PubMed

    Bersten, A D; Skowronski, G A; Oh, T E

    1986-08-01

    Desirable features of new generation intensive care ventilators include the ability to ventilate a wide range of patient sizes, an uncomplicated control panel, an appropriate but not excessive variety of ventilatory patterns, adequate patient monitoring and alarm functions, and simplicity of cleaning and routine maintenance. Examples of currently available ventilators include the Servo 900-C, CPU-1, Engstrom Erica, Bear 5, Drager EV-A and Hamilton Veolar. The incorporation of microcomputer control into some of these ventilators has resulted in improved flexibility and a limited number of automatic responses to detected patient changes. However, the function of components provided to allow spontaneous ventilation, such as demand valves, requires considerable improvement. Current trends in ventilator design include further refinement of computer control and the provision of graphic displays showing the results of continuous sophisticated analysis of respiratory function. The extent to which these developments will prove clinically useful will require careful evaluation.

  7. Liquid extracorporeal carbon dioxide removal: use of THAM (tris-hydroxymethyl aminomethane) coupled to hemofiltration to control hypercapnic acidosis in a porcine model of protective mechanical ventilation.

    PubMed

    Tapia, Pablo; Lillo, Felipe; Soto, Dagoberto; Escobar, Leslie; Simon, Felipe; Hernández, Karina; Alegría, Leyla; Bruhn, Alejandro

    2016-01-01

    A promising approach to facilitate protective mechanical ventilation is the use of extracorporeal CO2 removal techniques. Several strategies based on membrane gas exchangers have been developed. However, these techniques are still poorly available. The goal of this study was to assess the efficacy and safety of THAM infusion coupled to hemofiltration for the management of hypercapnic acidosis. A severe respiratory acidosis was induced in seven anesthetized pigs. Five of them were treated with THAM 8-mmol·kg(-1)·h(-1) coupled to hemofiltration (THAM+HF group) at 100 mL·kg(-1)·h(-1). After 18-hours of treatment the THAM infusion was stopped but hemofiltration was kept on until 24-hours. The 2 other animals were treated with THAM but without hemofiltration. After 1-hour of treatment in THAM+HF, PaCO2 rapidly decreased from a median of 89.0 (IQR) (80.0, 98.0) to 71.3 (65.8, 82.0) mmHg (P<0.05), while pH increased from 7.12 (7.01, 7.15) to 7.29 (7.27, 7.30) (P<0.05). Thereafter PaCO2 remained stable between 60-70 mmHg, while pH increased above 7.4. After stopping THAM at 18 hours of treatment a profound rebound effect was observed with severe hypercapnic acidosis. The most important side effect we observed was hyperosmolality, which reached a maximum of 330 (328, 332) mOsm·kg H2O(-1) at T18. The animals treated only with THAM developed severe hypercapnia, despite the fact that pH returned to normal values, and died after 12 hours. Control-group had an uneven evolution until the end of the experiment. A combined treatment with THAM coupled to hemofiltration may be an effective treatment to control severe hypercapnic acidosis.

  8. Protective garment ventilation system

    NASA Technical Reports Server (NTRS)

    Lang, R. (Inventor)

    1970-01-01

    A method and apparatus for ventilating a protective garment, space suit system, and/or pressure suits to maintain a comfortable and nontoxic atmosphere within is described. The direction of flow of a ventilating and purging gas in portions of the garment may be reversed in order to compensate for changes in environment and activity of the wearer. The entire flow of the ventilating gas can also be directed first to the helmet associated with the garment.

  9. Rescue Ventilation Through a Small-Bore Transtracheal Cannula in Severe Hypoxic Pigs Using Expiratory Ventilation Assistance

    PubMed Central

    Hamaekers, Ankie E.; van der Beek, Tim; Theunissen, Maurice

    2015-01-01

    BACKGROUND: Suction-generated expiratory ventilation assistance (EVA) has been proposed as a way to facilitate bidirectional ventilation through a small-bore transtracheal cannula (TC). In this study, we investigated the efficiency of ventilation with EVA for restoring oxygenation and ventilation in a pig model of acute hypoxia. METHODS: Six pigs (61–76 kg) were anesthetized and ventilated (intermittent positive pressure ventilation) via a cuffed endotracheal tube (ETT). Monitoring lines were placed, and a 75-mm long, 2-mm inner diameter TC was inserted. After the baseline recordings, the ventilator was disconnected. After 2 minutes of apnea, reoxygenation with EVA was initiated through the TC and continued for 15 minutes with the ETT occluded. In the second part of the study, the experiment was repeated with the ETT either partially obstructed or left open. Airway pressures and hemodynamic data were recorded, and arterial blood gases were measured. Descriptive statistical analysis was performed. RESULTS: With a completely or partially obstructed upper airway, ventilation with EVA restored oxygenation to baseline levels in all animals within 20 seconds. In a completely obstructed airway, Paco2 remained stable for 15 minutes. At lesser degrees of airway obstruction, the time to reoxygenation was delayed. Efficacy probably was limited when the airway was completely unobstructed, with 2 of 6 animals having a Pao2 <85 mm Hg even after 15 minutes of ventilation with EVA and a mean Paco2 increased up to 90 mm Hg. CONCLUSIONS: In severe hypoxic pigs, ventilation with EVA restored oxygenation quickly in case of a completely or partially obstructed upper airway. Reoxygenation and ventilation were less efficient when the upper airway was completely unobstructed. PMID:25565319

  10. Mechanical ventilation in children.

    PubMed

    Kendirli, Tanil; Kavaz, Asli; Yalaki, Zahide; Oztürk Hişmi, Burcu; Derelli, Emel; Ince, Erdal

    2006-01-01

    Mechanical ventilation can be lifesaving, but > 50% of complications in conditions that require intensive care are related to ventilatory support, particularly if it is prolonged. We retrospectively evaluated the medical records of patients who had mechanical ventilation in the Pediatric Intensive Care Unit (PICU) during a follow-up period between January 2002-May 2005. Medical records of 407 patients were reviewed. Ninety-one patients (22.3%) were treated with mechanical ventilation. Ages of all patients were between 1-180 (median: 8) months. The mechanical ventilation time was 18.8 +/- 14.1 days. Indication of mechanical ventilation could be divided into four groups as respiratory failure (64.8%), cardiovascular failure (19.7%), central nervous system disease (9.8%) and safety airway (5.4%). Tracheostomy was performed in four patients. The complication ratio of mechanically ventilated children was 42.8%, and diversity of complications was as follows: 26.3% atelectasia, 17.5% ventilator-associated pneumonia, 13.1% pneumothorax, 5.4% bleeding, 4.3% tracheal edema, and 2.1% chronic lung disease. The mortality rate of mechanically ventilated patients was 58.3%, but the overall mortality rate in the PICU was 12.2%. In conclusion, there are few published epidemiological data on the follow-up results and mortality in infants and children who are mechanically ventilated.

  11. Noninvasive ventilation in trauma

    PubMed Central

    Karcz, Marcin K; Papadakos, Peter J

    2015-01-01

    Trauma patients are a diverse population with heterogeneous needs for ventilatory support. This requirement depends mainly on the severity of their ventilatory dysfunction, degree of deterioration in gaseous exchange, any associated injuries, and the individual feasibility of potentially using a noninvasive ventilation approach. Noninvasive ventilation may reduce the need to intubate patients with trauma-related hypoxemia. It is well-known that these patients are at increased risk to develop hypoxemic respiratory failure which may or may not be associated with hypercapnia. Hypoxemia in these patients is due to ventilation perfusion mismatching and right to left shunt because of lung contusion, atelectasis, an inability to clear secretions as well as pneumothorax and/or hemothorax, all of which are common in trauma patients. Noninvasive ventilation has been tried in these patients in order to avoid the complications related to endotracheal intubation, mainly ventilator-associated pneumonia. The potential usefulness of noninvasive ventilation in the ventilatory management of trauma patients, though reported in various studies, has not been sufficiently investigated on a large scale. According to the British Thoracic Society guidelines, the indications and efficacy of noninvasive ventilation treatment in respiratory distress induced by trauma have thus far been inconsistent and merely received a low grade recommendation. In this review paper, we analyse and compare the results of various studies in which noninvasive ventilation was applied and discuss the role and efficacy of this ventilator modality in trauma. PMID:25685722

  12. Ventilatory failure, ventilator support, and ventilator weaning.

    PubMed

    Tobin, Martin J; Laghi, Franco; Jubran, Amal

    2012-10-01

    The development of acute ventilatory failure represents an inability of the respiratory control system to maintain a level of respiratory motor output to cope with the metabolic demands of the body. The level of respiratory motor output is also the main determinant of the degree of respiratory distress experienced by such patients. As ventilatory failure progresses and patient distress increases, mechanical ventilation is instituted to help the respiratory muscles cope with the heightened workload. While a patient is connected to a ventilator, a physician's ability to align the rhythm of the machine with the rhythm of the patient's respiratory centers becomes the primary determinant of the level of rest accorded to the respiratory muscles. Problems of alignment are manifested as failure to trigger, double triggering, an inflationary gas-flow that fails to match inspiratory demands, and an inflation phase that persists after a patient's respiratory centers have switched to expiration. With recovery from disorders that precipitated the initial bout of acute ventilatory failure, attempts are made to discontinue the ventilator (weaning). About 20% of weaning attempts fail, ultimately, because the respiratory controller is unable to sustain ventilation and this failure is signaled by development of rapid shallow breathing. Substantial advances in the medical management of acute ventilatory failure that requires ventilator assistance are most likely to result from research yielding novel insights into the operation of the respiratory control system.

  13. Liquid extracorporeal carbon dioxide removal: use of THAM (tris-hydroxymethyl aminomethane) coupled to hemofiltration to control hypercapnic acidosis in a porcine model of protective mechanical ventilation

    PubMed Central

    Tapia, Pablo; Lillo, Felipe; Soto, Dagoberto; Escobar, Leslie; Simon, Felipe; Hernández, Karina; Alegría, Leyla; Bruhn, Alejandro

    2016-01-01

    A promising approach to facilitate protective mechanical ventilation is the use of extracorporeal CO2 removal techniques. Several strategies based on membrane gas exchangers have been developed. However, these techniques are still poorly available. The goal of this study was to assess the efficacy and safety of THAM infusion coupled to hemofiltration for the management of hypercapnic acidosis. A severe respiratory acidosis was induced in seven anesthetized pigs. Five of them were treated with THAM 8-mmol·kg-1·h-1 coupled to hemofiltration (THAM+HF group) at 100 mL·kg-1·h-1. After 18-hours of treatment the THAM infusion was stopped but hemofiltration was kept on until 24-hours. The 2 other animals were treated with THAM but without hemofiltration. After 1-hour of treatment in THAM+HF, PaCO2 rapidly decreased from a median of 89.0 (IQR) (80.0, 98.0) to 71.3 (65.8, 82.0) mmHg (P<0.05), while pH increased from 7.12 (7.01, 7.15) to 7.29 (7.27, 7.30) (P<0.05). Thereafter PaCO2 remained stable between 60-70 mmHg, while pH increased above 7.4. After stopping THAM at 18 hours of treatment a profound rebound effect was observed with severe hypercapnic acidosis. The most important side effect we observed was hyperosmolality, which reached a maximum of 330 (328, 332) mOsm·kg H2O-1 at T18. The animals treated only with THAM developed severe hypercapnia, despite the fact that pH returned to normal values, and died after 12 hours. Control-group had an uneven evolution until the end of the experiment. A combined treatment with THAM coupled to hemofiltration may be an effective treatment to control severe hypercapnic acidosis. PMID:27648139

  14. Partially light-controlled imager based on liquid crystal plate and image intensifier for aurora and airglow measurement.

    PubMed

    Tang, Yuanhe; Cao, Xiangang; Liu, Hanchen; Shepherd, G G; Liu, Shulin; Gao, Haiyang; Yang, Xusan; Wu, Yong; Wang, Shuiwei

    2012-04-20

    In order to obtain information both of aurora and airglow in one image by the same detector, a PLCI based on liquid crystal plate LCP and super second-generation image intensifier SSGII is proposed in this research. The detection thresholds of the CCD for aurora and airglow are calculated. For the detectable illumination range of 10(4)-10(-2) lx, the corresponding electron count is 1.57×10(5) - 0.2 for every pixel of CCD. The structure and work principle of the PLCI are described. An LC is introduced in the front of CCD to decrease the intensities of aurora in overexposure areas by means of controlling transmittances pixel by pixel, while an image intensifier is set between the LC and CCD to increase the intensity of the weak airglow. The modulation transfer function MTF of this system is calculated as 0.391 at a Nyquist frequency of 15 lp/mm. The curve of transmittance with regard to gray level for the LC is obtained by calibration experiment. Based on the design principle, the prototype is made and used to take photos of objects under strong light greater than 2×10(5) lx. The clear details of [symbols: see text] presented in the image indicate that the PLCI can greatly improve the imaging quality. The theoretical calculations and experiment results prove that this device can extend the dynamic range and it provides a more effective method for upper atmospheric wind measurement.

  15. Review of Residential Ventilation Technologies

    SciTech Connect

    Armin Rudd

    2005-08-30

    This paper reviews current and potential ventilation technologies for residential buildings, including a variety of mechanical systems, natural ventilation, and passive ventilation. with particular emphasis on North American climates and construction.

  16. Surfactant-induced ordering and wetting transitions of droplets of thermotropic liquid crystals "caged" inside partially filled polymeric capsules.

    PubMed

    Carlton, Rebecca J; Zayas-Gonzalez, Yashira M; Manna, Uttam; Lynn, David M; Abbott, Nicholas L

    2014-12-16

    We report a study of the wetting and ordering of thermotropic liquid crystal (LC) droplets that are trapped (or "caged") within micrometer-sized cationic polymeric microcapsules dispersed in aqueous solutions of surfactants. When they were initially dispersed in water, we observed caged, nearly spherical droplets of E7, a nematic LC mixture, to occupy ∼40% of the interior volume of the polymeric capsules [diameter of 6.7 ± 0.3 μm, formed via covalent layer-by-layer assembly of branched polyethylenimine and poly(2-vinyl-4,4-dimethylazlactone)] and to contact the interior surface of the capsule wall at an angle of ∼157 ± 11°. The internal ordering of LC within the droplets corresponded to the so-called bipolar configuration (distorted by contact with the capsule walls). While the effects of dodecyltrimethylammonium bromide (DTAB) and sodium dodecyl sulfate (SDS) on the internal ordering of "free" LC droplets are similar, we observed the two surfactants to trigger strikingly different wetting and configurational transitions when LC droplets were caged within polymeric capsules. Specifically, upon addition of SDS to the aqueous phase, we observed the contact angles (θ) of caged LC on the interior surface of the capsule to decrease, resulting in a progression of complex droplet shapes, including lenses (θ ≈ 130 ± 10°), hemispheres (θ ≈ 89 ± 5°), and concave hemispheres (θ < 85°). The wetting transitions induced by SDS also resulted in changes in the internal ordering of the LC to yield states topologically equivalent to axial and radial configurations. Although topologically equivalent to free droplets, the contributions that surface anchoring, LC elasticity, and topological defects make to the free energy of caged LC droplets differ from those of free droplets. Overall, these results and others reported herein lead us to conclude that caged LC droplets offer a platform for new designs of LC-droplet-based responsive soft matter that cannot be

  17. Multifamily Ventilation Retrofit Strategies

    SciTech Connect

    Ueno, K.; Lstiburek, J.; Bergey, D.

    2012-12-01

    In multifamily buildings, central ventilation systems often have poor performance, overventilating some portions of the building (causing excess energy use), while simultaneously underventilating other portions (causing diminished indoor air quality). BSC and Innova Services Corporation performed a series of field tests at a mid-rise test building undergoing a major energy audit and retrofit, which included ventilation system upgrades.

  18. Guide to Home Ventilation

    SciTech Connect

    2010-10-01

    A fact sheet from the U.S. Department of Energy's Office of Energy Efficiency and Renewable Energy: Ventilation refers to the exchange of indoor and outdoor air. Without proper ventilation, an otherwise insulated and airtight house will seal in harmful pollutants, such as carbon monoxide, and moisture that can damage a house.

  19. Partial oxidation of liquid hydrocarbons in the presence of oxygen-conducting supports: Effect of catalyst layer deposition

    SciTech Connect

    Smith, M.; Berry, D.; Shekhawt, D.; Haynes, D.; Spivey, J.

    2010-01-01

    Ni-substituted barium hexaaluminate (BNHA) catalysts supported onto gadolinium-doped ceria (GDC), an oxygen-conductor, were prepared using two different methods: (1) conventional incipient wetness impregnation (IWI), in which a non-porous GDC support was impregnated in the conventional manner with aqueous precursors, then dried and calcined to form a supported hexaaluminate, and (2) solid-state mixing (SSM), in which solid hexaaluminate and GDC particles were mechanically ground together and thermally treated to produce a final catalyst. These catalysts were compared to bulk, unsupported BNHA; 3 wt% Ni/alumina; and 3 wt% Ni/GDC (the latter two prepared by conventional impregnation) for the partial oxidation (POX) of n-tetradecane. The reaction studies included examining the effect of 50 ppm S as dibenzothiophene (DBT) and 5 wt% 1-methylnaphthalene (MN) on the product yield under POX conditions. Temperature programmed oxidation (TPO) was used to characterize carbon formation in the reactor. The materials were characterized by BET, ICP-OES, XRD, and SEM/EDS prior to the reaction tests. Characterization of the two GDC-supported BNHA catalysts prior to the reaction studies indicated no significant differences in the bulk composition, surface area, and crystal structure. However, SEM images showed a larger amount of exposed GDC support surface area for the material prepared by IWI. Both of the GDC-supported BNHA materials demonstrated greatly reduced deactivation, with significantly reduced carbon formation compared to bulk BNHA. This was attributed to the oxygen-conducting property of the GDC, which reduced the rate of deactivation of the reaction sites by DBT and MN. The material prepared by IWI demonstrated more stable hydrogen and carbon monoxide yield than the material prepared by SSM. Although both catalysts deactivated in the presence of DBT and MN, the activity of the catalyst prepared by IWI recovered activity more quickly after the contaminants were removed

  20. Transport of a partially wetted particle at the liquid/vapor interface under the influence of an externally imposed surfactant generated Marangoni stress.

    PubMed

    Sharma, Ramankur; Corcoran, Timothy E; Garoff, Stephen; Przybycien, Todd M; Tilton, Robert D

    2017-05-20

    Marangoni flows offer an interesting and useful means to transport particles at fluid interfaces with potential applications such as dry powder pulmonary drug delivery. In this article, we investigate the transport of partially wetted particles at a liquid/vapor interface under the influence of Marangoni flows driven by gradients in the surface excess concentration of surfactants. We deposit a microliter drop of soluble (sodium dodecyl sulfate aqueous solution) surfactant solution or pure insoluble liquid (oleic acid) surfactant on a water subphase and observe the transport of a pre-deposited particle. Following the previous observation by Wang et al. [1] that a surfactant front rapidly advances ahead of the deposited drop contact line initiates particle motion but then moves beyond the particle, we now characterize the two dominant, time- and position-dependent forces acting on the moving particle: 1) a surface tension force acting on the three-phase contact line around the particle periphery due to the surface tension gradient at the liquid/vapor interface which always accelerates the particle and 2) a viscous force acting on the immersed surface area of the particle which accelerates or decelerates the particle depending on the difference in the velocities of the liquid and particle. We find that the particle velocity evolves over time in two regimes. In the acceleration regime, the net force on the particle acts in the direction of particle motion, and the particle quickly accelerates and reaches a maximum velocity. In the deceleration regime, the net force on the particle reverses and the particle decelerates gradually and stops. We identify the parameters that affect the two forces acting on the particle, including the initial particle position relative to the surfactant drop, particle diameter, particle wettability, subphase thickness, and surfactant solubility. We systematically vary these parameters and probe the spatial and temporal evolution of the two

  1. Oscillations and noise: inherent instability of pressure support ventilation?

    PubMed

    Hotchkiss, John R; Adams, Alexander B; Stone, Mary K; Dries, David J; Marini, John J; Crooke, Philip S

    2002-01-01

    Pressure support ventilation (PSV) is almost universally employed in the management of actively breathing ventilated patients with acute respiratory failure. In this partial support mode of ventilation, a fixed pressure is applied to the airway opening, and flow delivery is monitored by the ventilator. Inspiration is terminated when measured inspiratory flow falls below a set fraction of the peak flow rate (flow cutoff); the ventilator then cycles to a lower pressure and expiration commences. We used linear and nonlinear mathematical models to investigate the dynamic behavior of pressure support ventilation and confirmed the predicted behavior using a test lung. Our mathematical and laboratory analyses indicate that pressure support ventilation in the setting of airflow obstruction can be accompanied by marked variations in tidal volume and end-expiratory alveolar pressure, even when subject effort is unvarying. Unstable behavior was observed in the simplest plausible linear mathematical model and is an inherent consequence of the underlying dynamics of this mode of ventilation. The mechanism underlying the observed instability is "feed forward" behavior mediated by oscillatory elevation in end-expiratory pressure. In both mathematical and mechanical models, unstable behavior occurred at impedance values and ventilator settings that are clinically realistic.

  2. Design and economics of a lignite-to-SNG (substitute natural gas) facility using Lurgi gasifiers for lignite gasification and the Texaco Partial Oxidation Process to gasify Lurgi by-product liquids. Final topical report, April 1985-November 1985

    SciTech Connect

    Smith, J.T.; Smelser, S.C.

    1985-01-01

    A design and cost estimate was prepared for a 250 billion Btu/day lignite-to-SNG plant that uses Lurgi dry-bottom gasifiers to gasify lignite and the Texaco Partial Oxidation (POX) process to gasify the various hydrocarbon liquids produced by the Lurgi process. Also presented are plant performance and economic comparisons between this plant design and a Base Case design prepared previously in which the Lurgi by-product liquids are burned in boilers and superheaters for steam production. The cost-of-gas for the Study Case is approximately 1.5% higher than the cost-of-gas for the Base Case. It is slightly more economical to burn Lurgi liquids than to gasify them in an auxiliary unit, primarily because if liquids are gasified, additional coal-fired boilers are required for generation of process steam and these are substantially more expensive than boilers fired with liquid fuel.

  3. CFD and ventilation research.

    PubMed

    Li, Y; Nielsen, P V

    2011-12-01

    There has been a rapid growth of scientific literature on the application of computational fluid dynamics (CFD) in the research of ventilation and indoor air science. With a 1000-10,000 times increase in computer hardware capability in the past 20 years, CFD has become an integral part of scientific research and engineering development of complex air distribution and ventilation systems in buildings. This review discusses the major and specific challenges of CFD in terms of turbulence modelling, numerical approximation, and boundary conditions relevant to building ventilation. We emphasize the growing need for CFD verification and validation, suggest ongoing needs for analytical and experimental methods to support the numerical solutions, and discuss the growing capacity of CFD in opening up new research areas. We suggest that CFD has not become a replacement for experiment and theoretical analysis in ventilation research, rather it has become an increasingly important partner. We believe that an effective scientific approach for ventilation studies is still to combine experiments, theory, and CFD. We argue that CFD verification and validation are becoming more crucial than ever as more complex ventilation problems are solved. It is anticipated that ventilation problems at the city scale will be tackled by CFD in the next 10 years. © 2011 John Wiley & Sons A/S.

  4. Adaptive lung ventilation.

    PubMed

    Linton, D M

    2001-09-01

    Adaptive lung ventilation (ALV) is a method of closed-loop mechanical ventilation analogous to modern closed-loop technology in aviation such as the autopilot and automatic landing system. The algorithm of the controller of ALV is designed to automatically provide pressure-controlled synchronized intermittent mandatory ventilation (P-SIMV) and weaning as individually required in any clinical situation. The synchronized pressure limited breaths constantly adapt to the patient requirements to encourage optimal alveolar ventilation with minimal adverse physiological disturbance and timely weaning. The ease of application, efficiency, and safety of the first ALV controllers have been demonstrated in lung models, in patients with normal lungs undergoing general anesthesia, in patients requiring unusual positioning, in transition to and from one-lung anesthesia, and in long-term ventilation of patients with various lung pathologies and in weaning patients who have restrictive or obstructive pulmonary disease. Prospective comparative studies of ALV versus other currently used manually selected modes of mechanical ventilation, such as the one reported in this article, should confirm the safety and identify the benefits of this form of advanced closed-loop mechanical ventilation technology.

  5. Delayed mouth-caecum transit of a lactulose labelled liquid test meal in patients with steatorrhoea caused by partially treated coeliac disease.

    PubMed Central

    Spiller, R C; Lee, Y C; Edge, C; Ralphs, D N; Stewart, J S; Bloom, S R; Silk, D B

    1987-01-01

    Mouth-caecum transit time (M-CTT) of a lactulose labelled liquid test meal has been measured in 27 coeliac patients and 10 healthy controls using the breath hydrogen technique. Although all patients were urged to maintain a gluten free diet, not all did, and there was, therefore, a wide range in the severity of fat malabsorption within the patient group. Gastric emptying of a 113Indium DTPA-labelled liquid test meal was also assessed in separate studies on six healthy controls and 11 of the coeliac patients. Fasting breath hydrogen concentrations and the response to lactulose, as assessed both by the rate of rise, and the peak breath hydrogen concentration reached, showed no difference between coeliacs and controls, regardless of the presence or absence of steatorrhoea. Mouth-caecum transit time in the 16 coeliac patients with steatorrhea (faecal fat greater than 7 g/24 h) was, however, significantly prolonged being 158 +/- 18 minutes (mean +/- SEM), compared with 70 +/- 9 minutes for the controls (p less than 0.02), and 83 +/- 15 minutes for the 11 coeliacs without steatorrhoea (p less than 0.002). Mouth-caecum transit time in the coeliac patients was linearly related to the 24 hour faecal fat excretion, r = 0.55, n = 27, p less than 0.01. Slow mouth-caecum transit in the coeliacs with steatorrhoea was not caused by delayed gastric emptying as the t1/2 for coeliacs with steatorrhoea was within the normal range. Coeliacs with delayed mouth-caecum transit had impaired insulin release but the postprandial profiles of the other peptides measured (cholecystokinin, GIP, secretin, motilin, neurotensin, enteroglucagon, and peptide YY) were all within the normal range in this group of partially treated coeliac patients. PMID:3678957

  6. Ventilating Air-Conditioner

    NASA Technical Reports Server (NTRS)

    Dinh, Khanh

    1994-01-01

    Air-conditioner provides ventilation designed to be used alone or incorporated into cooling or heating system operates efficiently only by recirculating stale air within building. Energy needed to operate overall ventilating cooling or heating system slightly greater than operating nonventilating cooling or heating system. Helps to preserve energy efficiency while satisfying need for increased forced ventilation to prevent accumulation of undesired gases like radon and formaldehyde. Provides fresh treated air to variety of confined spaces: hospital surgeries, laboratories, clean rooms, and printing shops and other places where solvents used. In mobile homes and portable classrooms, eliminates irritant chemicals exuded by carpets, panels, and other materials, ensuring healthy indoor environment for occupants.

  7. Ventilating Air-Conditioner

    NASA Technical Reports Server (NTRS)

    Dinh, Khanh

    1994-01-01

    Air-conditioner provides ventilation designed to be used alone or incorporated into cooling or heating system operates efficiently only by recirculating stale air within building. Energy needed to operate overall ventilating cooling or heating system slightly greater than operating nonventilating cooling or heating system. Helps to preserve energy efficiency while satisfying need for increased forced ventilation to prevent accumulation of undesired gases like radon and formaldehyde. Provides fresh treated air to variety of confined spaces: hospital surgeries, laboratories, clean rooms, and printing shops and other places where solvents used. In mobile homes and portable classrooms, eliminates irritant chemicals exuded by carpets, panels, and other materials, ensuring healthy indoor environment for occupants.

  8. Newborn pig trachea cell line cultured in air-liquid interface conditions allows a partial in vitro representation of the porcine upper airway tissue

    PubMed Central

    2014-01-01

    Background The domestic pig is an excellent animal model to study human microbial diseases due to its similarity to humans in terms of anatomy, physiology, and genetics. We assessed the suitability of an in vitro air-liquid interface (ALI) culture system for newborn pig trachea (NPTr) cells as a practical tool for analyzing the immune response of respiratory epithelial cells to aggressors. This cell line offers a wide microbial susceptibility spectrum to both viruses and bacteria. The purpose of our study was to evaluate and characterize diverse aspects of cell differentiation using different culture media. After the NPTr cells reached confluence, the apical medium was removed and the cells were fed by medium from the basal side. Results We assessed the cellular layer’s capacity to polarize and differentiate in ALI conditions. Using immunofluorescence and electronic microscopy we evaluated the presence of goblet and ciliated cells, the epithelial junction organization, and the transepithelial electrical resistance. We found that the cellular layer develops a variable density of mucus producing cells and acquires a transepithelial resistance. We also identified increased development of cellular junctions over the culture period. Finally, we observed variable expression of transcripts associated to proteins such as keratin 8, mucins (MUC1, MUC2, and MUC4), occludin, and villin 1. Conclusions The culture of NPTr cells in ALI conditions allows a partial in vitro representation of porcine upper airway tissue that could be used to investigate some aspects of host/respiratory pathogen interactions. PMID:24885012

  9. Performance comparison of partial least squares-related variable selection methods for quantitative structure retention relationships modelling of retention times in reversed-phase liquid chromatography.

    PubMed

    Talebi, Mohammad; Schuster, Georg; Shellie, Robert A; Szucs, Roman; Haddad, Paul R

    2015-12-11

    The relative performance of six multivariate data analysis methods derived from or combined with partial least squares (PLS) has been compared in the context of quantitative structure-retention relationships (QSRR). These methods include, GA (genetic algorithm)-PLS, Monte Carlo uninformative variable elimination (MC-UVE), competitive adaptive reweighted sampling (CARS), iteratively retaining informative variables (IRIV), variable iterative space shrinkage approach (VISSA) and PLS with automated backward selection of predictors (autoPLS). A set of 825 molecular descriptors was computed for 86 suspected sports doping compounds and used for predicting their gradient retention times in reversed-phase liquid chromatography (RPLC). The correlation between molecular descriptors selected by each technique and the retention time was established using the PLS method. All models derived from a selected subset of descriptors outperformed the reference PLS model derived from all descriptors, with very small demands of computational time and effort. A performance comparison indicated great diversity of these methods in selecting the most relevant molecular descriptors, ranging from 28 for CARS to 263 for MC-UVE. While VISSA provided the lowest degree of over-fitting for the training set, CARS demonstrated the best compromise between the prediction accuracy and the number of selected descriptors, with the prediction error of as low as 46s for the external test set. Only ten descriptors were found to be common for all models, with the characteristics of these descriptors being representative of the retention mechanism in RPLC.

  10. Why We Ventilate

    SciTech Connect

    Logue, Jennifer M.; Sherman, Max H.; Price, Phil N.; Singer, Brett C.

    2011-09-01

    It is widely accepted that ventilation is critical for providing good indoor air quality (IAQ) in homes. However, the definition of"good" IAQ, and the most effective, energy efficient methods for delivering it are still matters of research and debate. This paper presents the results of work done at the Lawrence Berkeley National Lab to identify the air pollutants that drive the need for ventilation as part of a larger effort to develop a health-based ventilation standard. First, we present results of a hazard analysis that identified the pollutants that most commonly reach concentrations in homes that exceed health-based standards or guidelines for chronic or acute exposures. Second, we present results of an impact assessment that identified the air pollutants that cause the most harm to the U.S. population from chronic inhalation in residences. Lastly, we describe the implications of our findings for developing effective ventilation standards.

  11. Conventional mechanical ventilation

    PubMed Central

    Tobias, Joseph D.

    2010-01-01

    The provision of mechanical ventilation for the support of infants and children with respiratory failure or insufficiency is one of the most common techniques that are performed in the Pediatric Intensive Care Unit (PICU). Despite its widespread application in the PICUs of the 21st century, before the 1930s, respiratory failure was uniformly fatal due to the lack of equipment and techniques for airway management and ventilatory support. The operating rooms of the 1950s and 1960s provided the arena for the development of the manual skills and the refinement of the equipment needed for airway management, which subsequently led to the more widespread use of endotracheal intubation thereby ushering in the era of positive pressure ventilation. Although there seems to be an ever increasing complexity in the techniques of mechanical ventilation, its successful use in the PICU should be guided by the basic principles of gas exchange and the physiology of respiratory function. With an understanding of these key concepts and the use of basic concepts of mechanical ventilation, this technique can be successfully applied in both the PICU and the operating room. This article reviews the basic physiology of gas exchange, principles of pulmonary physiology, and the concepts of mechanical ventilation to provide an overview of the knowledge required for the provision of conventional mechanical ventilation in various clinical arenas. PMID:20927268

  12. Noninvasive ventilation: practical advice.

    PubMed

    Bello, Giuseppe; De Pascale, Gennaro; Antonelli, Massimo

    2013-02-01

    This critical review discusses the key points that would be of practical help for the clinician who applies noninvasive ventilation (NIV) for treatment of patients with acute respiratory failure (ARF). In recent years, the growing role of NIV in the acute care setting has led to the development of technical innovations to overcome the problems related to gas leakage and dead space. A considerable amount of research has been conducted to improve the quality of the devices as well as optimize ventilation modes used to administer NIV. As a result, also mechanical ventilators have been implemented with modalities aimed at delivering NIV. The success of NIV in patients with ARF depends on several factors, including the skills of the clinician, selection of patient, choice of interface, selection of ventilation mode and ventilator setting, monitoring, and the motivation of the patient. Recent advances in the understanding of the physiological aspects of using NIV through different interfaces and ventilator settings have led to improve patient-machine interaction, enhancing favorable NIV outcome.

  13. Dynamic Behaviour of Ventilated Hydrofoils.

    NASA Astrophysics Data System (ADS)

    Kjeldsen, Morten; Arndt, Roger; Wosnik, Martin

    2006-11-01

    In certain types of pumping applications oscillations are induced by operation with liquids containing a free gas load. In order to understand the physics of this process, a series of tests with a ventilated A 2D NACA 0015 hydrofoil were performed in the water tunnel at the St. Anthony Falls Laboratory of the University of Minnesota. The special bubble removal feature of the water tunnel allowed continuous ventilation without experiencing visible bubbles upstream the hydrofoil. These studies build on previous work on cavitation-induced oscillations. Gas injection studies were made over a range of gas flow rates and test section pressure. The results clearly show that lift oscillations increase in intensity when the gas load is increased. The point of maximum unsteadiness is also associated the rapid decline of the foil performance as measured as average lift. Further increase of the gas injection load gives a steady behaviour with almost no lift. These experiments are compared with traditional cavitation experiments. The similarities between gas injection- and cavitation induced unsteadiness on the hydrofoil are many, but the amplitude of lift oscillations found on the foil with gas injection corresponds to about 50% of that found for cavitating hydrofoils. The fact that the oscillations are periodic leads to the consideration of both passive and active control.

  14. Numerical heat transfer during partially-confined, confined, and free liquid jet impingement with rotation and chemical mechanical planarization process modeling

    NASA Astrophysics Data System (ADS)

    Lallave Cortes, Jorge C.

    This work presents the use of numerical modeling for the analysis of transient and steady state liquid jet impingement for cooling application of electronics, and energy dissipation during a CMP process under the influence of a series of parameters that controls the transport phenomena mechanism. Seven thorough studies were done to explore how the flow structure and conjugated heat transfer in both the solid and fluid regions was affected by adding a secondary rotational flow during the jet impingement process. Axis-symmetrical numerical models of round jets with a spinning or static nozzle were developed using the following configurations: confined, partially-confined, and free liquid jet impingement on a rotating or stationary uniformly heated disk of finite thickness and radius. Calculations were done for various materials, namely copper, silver, Constantan, and silicon with a solid to fluid thermal conductivity ratio covering a range of 36.91.2222, at different laminar Reynolds numbers ranging from 220 to 2,000, under a broad rotational rate range of 0 to 1,000 RPM (Ekman number=infinity--3.31x10--5), nozzle-to-plate spacing (beta=0.25.5.0), dimensionless disk thicknesses (b/dn=0.167.1.67), confinement ratio (rp/rd=0.2.0.75), and Prandtl number (1.29.124.44) using NH3, H2O, FC.77 and MIL.7808 as working fluids. An engineering correlation relating the average Nusselt number with the above parameters was developed for the prediction of system performance. The simulation results compared reasonably well with previous experimental studies. The second major contribution of this research was the development of a three dimensional CMP model that shows the temperature distributions profile as an index of energy dissipation at the wafer and pad surfaces, and slurry interface. A finite element analysis was done with FIDAP 8.7.4 package under the influence of physical parameters, such as slurry flow rates (0.5.1.42 cc/s), polishing pressures (17.24.41.37 kPa), pad

  15. 14 CFR 25.831 - Ventilation.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction Ventilation and Heating § 25.831 Ventilation... probable failures or malfunctioning of the ventilating, heating, pressurization, or other systems...

  16. 14 CFR 25.831 - Ventilation.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction Ventilation and Heating § 25.831 Ventilation... probable failures or malfunctioning of the ventilating, heating, pressurization, or other systems...

  17. 14 CFR 25.831 - Ventilation.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction Ventilation and Heating § 25.831 Ventilation... probable failures or malfunctioning of the ventilating, heating, pressurization, or other systems...

  18. 14 CFR 25.831 - Ventilation.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction Ventilation and Heating § 25.831 Ventilation... probable failures or malfunctioning of the ventilating, heating, pressurization, or other systems...

  19. Weaning from artificial ventilation.

    PubMed

    Mancebo, J

    1998-06-01

    Every intubated and mechanically-ventilated patient should be clinically evaluated, at least on a daily basis, by a skilled team in order to speed up the weaning process as much as possible. Again, it should be emphasized that the adoption of an active clinical strategy when faced with "difficult" to wean patients is of paramount importance. In one study, performed in Spain, analysing the prevalence of mechanical ventilation in intensive care units [3], reported the mean number of days that patients spent on mechanical ventilation was 27. In a more recent intervention study, in which a specific protocol was followed each day [2], the mean number of days on mechanical ventilation was only 12. These data have been confirmed by several authors [4, 40], and it has also been reported that a protocol-directed weaning strategy leads not only to a significant reduction in the duration of mechanical ventilation but also to a significant decrease in the number of complications and cost [4]. However, even following a protocol-directed weaning strategy, it is possible that weaning duration can be further reduced. In a prospective study performed in our institution [41] during 32 months, we reported that, following an episode of unplanned extubation, the only independent variables associated with the need for reintubation were the number of days of mechanical ventilation and the type of ventilatory support at the time of autoextubation. Indeed, when patients were in the weaning period only 16% (5 out of 32) needed reintubation, whereas reintubation was needed in 82% (22 out of 27) of patients who had an unplanned extubation during full mechanical ventilatory support. These data suggest that there are still some patients being on mechanical ventilation for a longer than necessary period of time. Finally, very recent advances in technological areas such as artificial intelligence, are proving to be useful in the management of the weaning process. When such systems are applied to

  20. Determination of selectivity differences for basic compounds in gradient reverse phase high performance liquid chromatography under high pH conditions by partial least squares modelling.

    PubMed

    Fornal, Emilia; Borman, Phil; Luscombe, Christopher

    2006-06-16

    The retention behaviour of compounds in a chromatographic system is believed to be multivariate by nature, i.e. many physico-chemical properties of an analyte can influence its retention. Principal component analysis (PCA) and partial least squares (PLS) can therefore be particularly useful tools for visualising, exploring and modelling the complex interactions between solutes and the mobile and stationary phase. PCA allows the relationships between compounds (the observations) and their retention parameters (the variables) to be visualised in usually just two or three dimensions. PLS can be used to model quantitative structure-retention relationships (QSRRs) and may lead to better understanding of retention and selectivity changes in chromatographic systems. The objective of the study was to investigate the chromatographic behaviour of basic compounds under optimised gradient conditions using octadecyl high performance liquid chromatography (HPLC) columns designed for high pH separations. Three pharmaceutical mixtures were analysed by linear gradient reverse phase HPLC (RP-HPLC) at high pH using ammonia as a pH modifier, and methanol and/or acetonitrile as the organic modifier. The separations were carried out on three octadecyl columns: Waters XTerra MS C18, Agilent Zorbax Extend C18 and Thermo Hypersil-Keystone BetaBasic-18. Multivariate PCA and PLS modelling were employed to explore and explain the differences in selectivity between the chromatographic systems studied when the basic compounds were analysed under the high pH conditions. The interactions between the analytes and the mobile-stationary phases were described by relating the compound molecular descriptors with the selectivity of each chromatographic system. The selectivity differences between the chromatographic systems were identified.

  1. Ventilation technologies scoping study

    SciTech Connect

    Walker, Iain S.; Sherman, Max H.

    2003-09-30

    This document presents the findings of a scoping study commissioned by the Public Interest Energy Research (PIER) program of the California Energy Commission to determine what research is necessary to develop new residential ventilation requirements for California. This study is one of three companion efforts needed to complete the job of determining the needs of California, determining residential ventilation requirements, and determining appropriate ventilation technologies to meet these needs and requirements in an energy efficient manner. Rather than providing research results, this scoping study identifies important research questions along with the level of effort necessary to address these questions and the costs, risks, and benefits of pursuing alternative research questions. In approaching these questions and level of effort, feasibility and timing were important considerations. The Commission has specified Summer 2005 as the latest date for completing this research in time to update the 2008 version of California's Energy Code (Title 24).

  2. Ventilation flow: Submerged

    NASA Technical Reports Server (NTRS)

    Hutchinson, D.

    1985-01-01

    The ventilation system on a submarine is discussed. When the submarine is submerged. The ventilation system provides a conditioned atmosphere in the ship with complete isolation from the outside. A conditioned atmosphere includes not only filtration and temperature and humidity control, but also air purification (removal of potentially harmful quantities of impurities and comtaminants) and revitalization (addition of vital life support oxygen). Carbon dioxide removal, the oxygen system, air conditioning, carbon monoxide removal, hydrogen removal, and atmosphere monitoring systems are among the topics discussed.

  3. Bench performance of ventilators during simulated paediatric ventilation.

    PubMed

    Park, M A J; Freebairn, R C; Gomersall, C D

    2013-05-01

    This study compares the accuracy and capabilities of various ventilators using a paediatric acute respiratory distress syndrome lung model. Various compliance settings and respiratory rate settings were used. The study was done in three parts: tidal volume and FiO2 accuracy; pressure control accuracy and positive end-expiratory pressure (PEEP) accuracy. The parameters set on the ventilator were compared with either or both of the measured parameters by the test lung and the ventilator. The results revealed that none of the ventilators could consistently deliver tidal volumes within 1 ml/kg of the set tidal volume, and the discrepancy between the delivered volume and the volume measured by the ventilator varied greatly. The target tidal volume was 8 ml/kg, but delivered tidal volumes ranged from 3.6-11.4 ml/kg and the volumes measured by the ventilator ranged from 4.1-20.6 ml/kg. All the ventilators maintained pressure within 20% of the set pressure, except one ventilator which delivered pressures of up to 27% higher than the set pressure. Two ventilators maintained PEEP within 10% of the prescribed PEEP. The majority of the readings were also within 10%. However, three ventilators delivered, at times, PEEPs over 20% higher. In conclusion, as lung compliance decreases, especially in paediatric patients, some ventilators perform better than others. This study highlights situations where ventilators may not be able to deliver, nor adequately measure, set tidal volumes, pressure, PEEP or FiO2.

  4. Meeting Residential Ventilation Standards Through Dynamic Control of Ventilation Systems

    SciTech Connect

    Sherman, Max H.; Walker, Iain S.

    2011-04-01

    Existing ventilation standards, including American Society of Heating, Refrigerating, and Air-conditioning Engineers (ASHRAE) Standard 62.2, specify continuous operation of a defined mechanical ventilation system to provide minimum ventilation, with time-based intermittent operation as an option. This requirement ignores several factors and concerns including: other equipment such as household exhaust fans that might incidentally provide ventilation, negative impacts of ventilation when outdoor pollutant levels are high, the importance of minimizing energy use particularly during times of peak electricity demand, and how the energy used to condition air as part of ventilation system operation changes with outdoor conditions. Dynamic control of ventilation systems can provide ventilation equivalent to or better than what is required by standards while minimizing energy costs and can also add value by shifting load during peak times and reducing intake of outdoor air contaminants. This article describes the logic that enables dynamic control of whole-house ventilation systems to meet the intent of ventilation standards and demonstrates the dynamic ventilation system control concept through simulations and field tests of the Residential Integrated Ventilation-Energy Controller (RIVEC).

  5. Pulmonary ventilation/perfusion scan

    MedlinePlus

    ... JavaScript. A pulmonary ventilation/perfusion scan involves two nuclear scan tests to measure breathing (ventilation) and circulation ( ... In: Mettler FA, Guiberteau MJ, eds. Essentials of Nuclear Medicine Imaging . 6th ed. Philadelphia, PA: Elsevier Saunders; ...

  6. Central Fan Integrated Ventilation Systems

    SciTech Connect

    2009-05-12

    This information sheet describes one example of a ventilation system design, a central fan integrated supply (CFIS) system, a mechanical ventilation and pollutant source control to ensure that there is reasonable indoor air quality inside the house.

  7. Inert gas analysis of ventilation-perfusion matching during hemodialysis.

    PubMed Central

    Ralph, D D; Ott, S M; Sherrard, D J; Hlastala, M P

    1984-01-01

    The mechanism of hypoxemia during hemodialysis was investigated by the multiple inert gas elimination technique in anesthetized, paralyzed, mechanically ventilated dogs. Profound leukopenia occurred in the first hour of a 2-h hemodialysis with a cuprophan membrane and dialysate that contained acetate. Arterial partial pressure of O2 and CO2 and oxygen consumption remained unchanged during dialysis. Pulmonary carbon dioxide elimination and lung respiratory exchange ratio decreased with the initiation of dialysis, remained depressed throughout the duration of dialysis, and returned to predialysis levels after the cessation of dialysis. Cardiac output diminished during dialysis but did not return to base-line levels after dialysis. Multiple indices calculated from inert gas analysis revealed no ventilation-perfusion mismatching during dialysis. The shunt and perfusion to regions of low alveolar ventilation-to-perfusion ratio (VA/Q) were unchanged during dialysis. There was no change in the mean or standard deviation of the profile of the percentage of total perfusion to regions of the lung that had VA/Q near 1.0; nor was there any increase in the directly calculated arterial-alveolar partial pressure differences for the inert gases during dialysis. Dead space became mildly elevated during dialysis. These results show that during dialysis with controlled ventilation there is no ventilation-perfusion mismatching that leads to hypoxemia. During spontaneous ventilation any hypoxemia must occur due to hypoventilation secondary to the CO2 exchange by the dialyzer and subsequent reduction in pulmonary CO2 exchange. PMID:6715542

  8. How to Plan Ventilation Systems.

    ERIC Educational Resources Information Center

    Clarke, John H.

    1963-01-01

    Ventilation systems for factory safety demand careful planning. The increased heat loads and new processes of industry have introduced complex ventilation problems in--(1) ventilation supply, (2) duct work design, (3) space requirements, (4) hood face velocities, (5) discharge stacks, and (6) building eddies. This article describes and diagrams…

  9. How to Plan Ventilation Systems.

    ERIC Educational Resources Information Center

    Clarke, John H.

    1963-01-01

    Ventilation systems for factory safety demand careful planning. The increased heat loads and new processes of industry have introduced complex ventilation problems in--(1) ventilation supply, (2) duct work design, (3) space requirements, (4) hood face velocities, (5) discharge stacks, and (6) building eddies. This article describes and diagrams…

  10. The use of partially porous particle columns for the routine, generic analysis of biological samples for pharmacokinetic studies in drug discovery by reversed-phase ultra-high performance liquid chromatography-tandem mass spectrometry.

    PubMed

    Mallett, David N; Ramírez-Molina, César

    2009-01-15

    Recent years have seen the introduction of new high performance liquid chromatography (HPLC) instruments and columns that are capable of achieving high resolution, high speed liquid chromatographic separations at back pressures up to 1000 bar, so-called ultra-high performance liquid chromatography (UHPLC). Ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS) is gaining widespread use for this purpose, and for this approach to be successful a generically applicable, robust column is required. Here, data are presented showing the robustness of a partially porous 2.7 microm diameter particle material in this application and the accuracy and precision of an assay for a typical pharmaceutical in plasma. This stationary phase material is evaluated for performance and compared with other materials frequently used for similar analyses using a test mix currently used routinely in our laboratories to assess the performance of UHPLC-MS/MS systems. The partially porous material demonstrates similar resolving power to sub-2 microm materials under the ballistic gradient chromatography conditions employed and exhibits excellent resilience over the analysis of thousands of protein precipitated plasma extracts. It is suggested that this stationary phase material can be an invaluable tool in generic, high throughput assays for pharmaceutical bioanalysts.

  11. Measure Guideline: Ventilation Cooling

    SciTech Connect

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

    2012-04-01

    The purpose of this measure guideline on ventilation cooling is to provide information on a cost-effective solution for reducing cooling system energy and demand in homes located in hot-dry and cold-dry climates. This guideline provides a prescriptive approach that outlines qualification criteria, selection considerations, and design and installation procedures.

  12. Non-invasive ventilation.

    PubMed Central

    Spence, D.

    1996-01-01

    Nasal intermittent positive pressure ventilation is an effective treatment for nocturnal hypoventilation secondary to chest wall deformity or respiratory muscle weakness. Physicians should be aware that, in these groups of patients, disabling breathlessness can be alleviated and established cor pulmonale reversed by the technique. Images Figure 1 Figure 2 Figure 3 PMID:8949588

  13. Ventilator-associated pneumonia.

    PubMed

    Morehead, R S; Pinto, S J

    2000-07-10

    Ventilator-associated pneumonia is a common complication in intensive care units, occurring in 9% to 24% of patients intubated for longer than 48 hours. Because of this large disease burden and the resultant attributable morbidity and mortality, there is great interest in accurately diagnosing, treating, and preventing this complication. More severely ill patients tend to develop ventilator-associated pneumonia, and identified risk factors include prolonged mechanical ventilation, reintubation after failed extubation, and a few other clinical variables. The efficacy of diagnostic and preventive strategies is somewhat controversial. Diagnosis by invasive methods requires a considerable commitment of resources but can potentially reduce cost of care; however, mortality benefit from this approach has not been demonstrated. As such, in most institutions, ventilator-associated pneumonia is best diagnosed using traditional clinical criteria. Prompt administration of appropriate antibiotics seems to be the only intervention that alters outcome once the diagnosis is established. Several strategies seem to reduce pneumonia incidence; however, mortality and cost benefits have yet to be convincingly shown.

  14. Energy recovery ventilator

    SciTech Connect

    Schneider, S. L.; Dravnieks, K.

    1985-04-30

    An energy recovery ventilator adapted to be mounted on a roof and adapted to be connected to the outlet of an exhaust air duct of a building ventilation system and the inlet of an air supply duct of a building ventilation system. The energy recovery ventilator includes a housing having an exhaust air chamber and a supply air chamber separated by a divider wall. A circular heat transfer wheel is position in the housing, a portion of the wheel being housed in the exhaust air chamber and a second portion of the wheel being housed in the supply air chamber, and the heat transfer wheel is caused to rotate about a central axis. An exhaust fan is housed in the exhaust air chamber and causes exhaust air to be pulled through the exhaust air duct and the heat transfer wheel and to be exhausted from the housing. A supply air fan is housed in the supply air housing above the heat transfer wheel, and causes outside air to be drawn into the supply air chamber and to be forced through the heat transfer wheel into the air supply duct.

  15. Understanding mechanical ventilators.

    PubMed

    Chatburn, Robert L

    2010-12-01

    The respiratory care academic community has not yet adopted a standardized system for classifying and describing modes of ventilation. As a result, there is enough confusion that patient care, clinician education and even ventilator sales are all put at risk. This article summarizes a ventilator mode taxonomy that has been extensively published over the last 15 years. Specifically, the classification system has three components: a description of the control variables within breath; a description of the sequence of mandatory and spontaneous breaths; and a specification for the targeting scheme. This three-level specification provides scalability of detail to make the mode description appropriate for the particular need. At the bedside, we need only refer to a mode briefly using the first or perhaps first and second components. To distinguish between similar modes and brand names, we would need to include all components. This taxonomy uses the equation of motion for the respiratory system as the underlying theoretical framework. All terms relevant to describing modes of mechanical ventilation are defined in an extensive appendix.

  16. Laboratory Ventilation and Safety.

    ERIC Educational Resources Information Center

    Steere, Norman V.

    1965-01-01

    In order to meet the needs of both safety and economy, laboratory ventilation systems must effectively remove air-borne toxic and flammable materials and at the same time exhaust a minimum volume of air. Laboratory hoods are the most commonly used means of removing gases, dusts, mists, vapors, and fumed from laboratory operations. To be effective,…

  17. Space station ventilation study

    NASA Technical Reports Server (NTRS)

    Colombo, G. V.; Allen, G. E.

    1972-01-01

    A ventilation system design and selection method which is applicable to any manned vehicle were developed. The method was used to generate design options for the NASA 33-foot diameter space station, all of which meet the ventilation system design requirements. System characteristics such as weight, volume, and power were normalized to dollar costs for each option. Total system costs for the various options ranged from a worst case $8 million to a group of four which were all approximately $2 million. A system design was then chosen from the $2 million group and is presented in detail. A ventilation system layout was designed for the MSFC space station mockup which provided comfortable, efficient ventilation of the mockup. A conditioned air distribution system design for the 14-foot diameter modular space station, using the same techniques, is also presented. The tradeoff study resulted in the selection of a system which costs $1.9 million, as compared to the alternate configuration which would have cost $2.6 million.

  18. Rehabilitation of spinal cord injured patients on long term ventilation.

    PubMed

    Chawla, J C

    1993-02-01

    Recent advances in roadside management and resuscitation techniques have resulted in an increased survival rate of people with high cervical cord injury. A few become partially or permanently ventilator dependent. Not only are these people dependent on assisted ventilation, but their speech is also compromised, along with loss of voluntary control and many other bodily functions, as they are tetraplegic. By using recent technological advancements, such as portable ventilators, phrenic nerve stimulation, environmental controls and specialised wheelchairs it has been possible to manage such patients at home. Furthermore, patients on ventilators are unable to have verbal communication. There is therefore a need for them to develop either augmentative communication or the use of alternative communication aids. Recent published reports indicate the factors other than the clinical state that may prevent such patients from taking advantage of modern advances; the main issues appear to be cost factors, community care provision and ethical considerations.

  19. 46 CFR 153.314 - Ventilation of spaces not usually occupied.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Ventilation of spaces not usually occupied. 153.314 Section 153.314 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Handling Space Ventilation §...

  20. 46 CFR 153.314 - Ventilation of spaces not usually occupied.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Ventilation of spaces not usually occupied. 153.314 Section 153.314 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Handling Space Ventilation §...

  1. Patient-ventilator dyssynchrony during assisted invasive mechanical ventilation.

    PubMed

    Murias, G; Villagra, A; Blanch, L

    2013-04-01

    Patient-ventilator dyssynchrony is common during mechanical ventilation. Dyssynchrony decreases comfort, prolongs mechanical ventilation and intensive care unit stays, and might lead to worse outcome. Dyssynchrony can occur during the triggering of the ventilator, the inspiration period after triggering, the transition from inspiration to expiration, and the expiratory phase. The most common dyssynchronies are delayed triggering, autotriggering, ineffective inspiratory efforts (which can occur at any point in the respiratory cycle), mismatch between the patient's and ventilator's inspiratory times, and double triggering. At present, the detection of dyssynchronies usually depends on healthcare staff observing ventilator waveforms; however, performance is suboptimal and many events go undetected. To date, technological complexity has made it impossible to evaluate patient-ventilator synchrony throughout the course of mechanical ventilation. Studies have shown that a high index of dyssynchrony may increase the duration of mechanical ventilation. Better training, better ventilatory modes, and/or computerized systems that permit better synchronization of patients' demands and ventilator outputs are necessary to improve patient-ventilator synchrony.

  2. Comparison of respiratory and hemodynamic stability in patients with traumatic brain injury ventilated by two ventilator modes: Pressure regulated volume control versus synchronized intermittent mechanical ventilation

    PubMed Central

    Aghadavoudi, Omid; Alikiaii, Babak; Sadeghi, Fariba

    2016-01-01

    Background: This study aimed to compare pressure regulated volume control (PRVC) and synchronized intermittent mechanical ventilation (SIMV) modes of ventilation according to respiratory and hemodynamic stability in patients with traumatic brain injury (TBI) admitted to Intensive Care Unit (ICU). Materials and Methods: In a randomized, single-blinded, clinical trial study, 100 patients who hospitalized in ICU due to TBI were selected and randomly divided into two groups. The first and second groups were ventilated by PRVC and SIMV modes, respectively. During mechanical ventilation, arterial blood gas and respiratory and hemodynamic parameters were also recorded and compared between the two groups. Results: According to the t-test, the mean rapid shallow breathing index (RSBI) after the first 8 h of mechanical ventilation was significantly higher in SIMV group compared with PRVC group (107.6 ± 2.75 vs. 102.2 ± 5.2, respectively, P < 0.0001). Further, according to ANOVA with repeated measures, the trend of RSBI changes had a significant difference between the two groups (P < 0.001). The trend of ratio of partial pressure arterial oxygen and fraction of inspired oxygen was different between the two groups according to Mann–Whitney–Wilcoxon test (P < 0.001). Conclusions: Using PRVC mode might be more desirable than using SIMV mode in patients with TBI due to better stability of ventilation and oxygenating. To ensure for more advantages of PRVC mode, further studies with longer follow-up and more detailed measurements are recommended. PMID:28028515

  3. Performance characteristics of five new anesthesia ventilators and four intensive care ventilators in pressure-support mode: a comparative bench study.

    PubMed

    Jaber, Samir; Tassaux, Didier; Sebbane, Mustapha; Pouzeratte, Yvan; Battisti, Anne; Capdevila, Xavier; Eledjam, Jean-Jacques; Jolliet, Philippe

    2006-11-01

    During the past few years, many manufacturers have introduced new modes of ventilation in anesthesia ventilators, especially partial-pressure modalities. The current bench test study was designed to compare triggering and pressurization of five new anesthesia ventilators with four intensive care unit ventilators. Ventilators were connected to a two-compartment lung model. One compartment was driven by an intensive care unit ventilator to mimic "patient" inspiratory effort, whereas the other was connected to the tested ventilator. The settings of ventilators were positive end-expiratory pressures of 0 and 5 cm H2O, and pressure-support ventilation levels of 10, 15, and 20 cm H2O with normal and high "patient" inspiratory effort. For the anesthesia ventilators, all the measurements were obtained for a low (1 l/min) and a high (10 l/min) fresh gas flow. Triggering delay, triggering workload, and pressurization at 300 and 500 ms were analyzed. For the five tested anesthesia ventilators, the pressure-support ventilation modality functioned correctly. For inspiratory triggering, the three most recent anesthesia machines (Fabius, Drägerwerk AG, Lübeck, Germany; Primus, Drägerwerk AG; and Avance, GE-Datex-Ohemda, Munchen, Germany) had a triggering delay of less than 100 ms, which is considered clinically satisfactory and is comparable to intensive care unit machines. The use of positive end-expiratory pressure modified the quality of delivered pressure support for two anesthesia ventilators (Kion, Siemens AG, Munich, Germany; and Felix, Taema, Antony, France). Three of the five anesthesia ventilators exhibited pressure-support ventilation performance characteristics comparable to those of the intensive care unit machines. Increasing fresh gas flow (1 to 10 l/min) in the internal circuit did not influence the pressure-support ventilation performance of the anesthesia ventilators. Regarding trigger sensitivity and the system's ability to meet inspiratory flow during

  4. ASHRAE and residential ventilation

    SciTech Connect

    Sherman, Max H.

    2003-10-01

    In the last quarter of a century, the western world has become increasingly aware of environmental threats to health and safety. During this period, people psychologically retreated away from outdoors hazards such as pesticides, smog, lead, oil spills, and dioxin to the seeming security of their homes. However, the indoor environment may not be healthier than the outdoor environment, as has become more apparent over the past few years with issues such as mold, formaldehyde, and sick-building syndrome. While the built human environment has changed substantially over the past 10,000 years, human biology has not; poor indoor air quality creates health risks and can be uncomfortable. The human race has found, over time, that it is essential to manage the indoor environments of their homes. ASHRAE has long been in the business of ventilation, but most of the focus of that effort has been in the area of commercial and institutional buildings. Residential ventilation was traditionally not a major concern because it was felt that, between operable windows and envelope leakage, people were getting enough outside air in their homes. In the quarter of a century since the first oil shock, houses have gotten much more energy efficient. At the same time, the kinds of materials and functions in houses changed in character in response to people's needs. People became more environmentally conscious and aware not only about the resources they were consuming but about the environment in which they lived. All of these factors contributed to an increasing level of public concern about residential indoor air quality and ventilation. Where once there was an easy feeling about the residential indoor environment, there is now a desire to define levels of acceptability and performance. Many institutions--both public and private--have interests in Indoor Air Quality (IAQ), but ASHRAE, as the professional society that has had ventilation as part of its mission for over 100 years, is the

  5. Ventilator-associated pneumonia.

    PubMed

    2009-11-01

    Ventilator-associated pneumonia is a pneumonia that develops initially more than 48 h from the start of tracheal intubation and mechanical ventilation. The route of infection is almost always through the respiratory tract. Intake of contaminants from outside the tracheal tube (silent aspiration) is considered a key route, and suctioning of secretions that have accumulated above the cuff of the endotracheal tubes is effective in preventing infection. The circuit is managed and heated-wire humidifiers and suction are manipulated based on appropriate infection control measures. To diagnose pathogens, efforts should be made to collect specimens from the pneumonia focus. Realistically, however, diagnosis can also be achieved based on the clinical course and from the results of culture of samples from tracheal aspirate. Use of prophylactic antimicrobials is not recommended, but once a diagnosis is made, antimicrobials are administered that combat the causative microorganism.

  6. 46 CFR 153.310 - Ventilation system type.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Ventilation system type. 153.310 Section 153.310 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo...

  7. [Non-invasive ventilation].

    PubMed

    Gallardo Romero, Jose Manuel; García, Teresa Gómez; Sancho Chust, José Norberto; González Martínez, Mónica

    2010-10-01

    The advent of non-invasive mechanical ventilation (NIMV) has radically changed the management of acute and chronic respiratory failure. Over the last few years, the number of possible applications of NIMV has progressively increased, both in the hospital and extrahospital setting. NIMV is now used in all hospitals and resident physicians currently receive specific training -nonexistent until a few years ago- in this modality. It falls to all of us to push forward the clinical and scientific advances represented by the development of NIMV, by promoting the events that accompany better knowledge of the physiopathological bases of ventilation and of its continuous applications in daily clinical practice and by perfecting the elements required for the correct application of this technique. The present review aims to provide a broad overview of NIMV, from the most theoretical knowledge (the physiopathology of NIMV) to the most practical skills (recognition of patient-ventilator asynchrony). Through this progression from the complex to the most basic, or from the basics to the most complex, depending on the perspective taken, we aim to provide deeper knowledge of the concepts required to understand the technical functioning of the ventilator, describing its distinct modes and parameters and the abilities that must be developed for the correct indication, use and monitoring of the technique. We provide a final reflection on other forms of respiratory support that can be offered to patients with ventilatory failure. Copyright © 2010 Sociedad Española de Neumología y Cirugía Torácica. Published by Elsevier Espana. All rights reserved.

  8. Oven ventilation system

    SciTech Connect

    Brewer, D.E.

    1987-02-17

    A ventilation system is described for venting an oven with external surfaces, the oven being located within an enclosed space, the system comprising: intake means for collecting air from the external environment of the enclosed space; means for forming a sheet of the air and passing the sheet across the external surfaces of the oven; and exhaust means for exhausting the sheet of the air to the external environment of the enclosed space after the air has been passed across the external surfaces.

  9. Harnessing natural ventilation benefits.

    PubMed

    O'Leary, John

    2013-04-01

    Making sure that a healthcare establishment has a good supply of clean fresh air is an important factor in keeping patients, staff, and visitors, free from the negative effects of CO2 and other contaminants. John O'Leary of Trend Controls, a major international supplier of building energy management solutions (BEMS), examines the growing use of natural ventilation, and the health, energy-saving, and financial benefits, that it offers.

  10. Monitoring of regional lung ventilation using electrical impedance tomography after cardiac surgery in infants and children.

    PubMed

    Krause, Ulrich; Becker, Kristin; Hahn, Günter; Dittmar, Jörg; Ruschewski, Wolfgang; Paul, Thomas

    2014-08-01

    Electrical impedance tomography (EIT) is a noninvasive method to monitor regional lung ventilation in infants and children without using radiation. The objective of this prospective study was to determine the value of EIT as an additional monitoring tool to assess regional lung ventilation after pediatric cardiac surgery for congenital heart disease in infants and children. EIT monitoring was performed in a prospective study comprising 30 pediatric patients who were mechanically ventilated after cardiac surgery. Data were analyzed off-line with respect to regional lung ventilation in different clinical situations. EIT data were correlated with respirator settings and arterial carbon dioxide (CO2) partial pressure in the blood. In 29 of 30 patients, regional ventilation of the lung could sufficiently and reliably be monitored by means of EIT. The effects of the transition from mechanical ventilation to spontaneous breathing after extubation on regional lung ventilation were studied. After extubation, a significant decrease of relative impedance changes was evident. In addition, a negative correlation of arterial CO2 partial pressure and relative impedance changes could be shown. EIT was sufficient to discriminate differences of regional lung ventilation in children and adolescents after cardiac surgery. EIT reliably provided additional information on regional lung ventilation in children after cardiac surgery. Neither chest tubes nor pacemaker wires nor the intensive care unit environment interfered with the application of EIT. EIT therefore may be used as an additional real-time monitoring tool in pediatric cardiac intensive care because it is noninvasive.

  11. Home Mechanical Ventilation in Children.

    PubMed

    Preutthipan, Aroonwan

    2015-09-01

    The number of children dependent on home mechanical ventilation has been reported to be increasing in many countries around the world. Home mechanical ventilation has been well accepted as a standard treatment of children with chronic respiratory failure. Some children may need mechanical ventilation as a lifelong therapy. To send mechanically ventilated children back home may be more difficult than adults. However, relatively better outcomes have been demonstrated in children. Children could be safely ventilated at home if they are selected and managed properly. Conditions requiring home ventilation include increased respiratory load from airway or lung pathologies, ventilatory muscle weakness and failure of neurologic control of ventilation. Home mechanical ventilation should be considered when the patient develops progressive respiratory failure or intractable failure to wean mechanical ventilation. Polysomnography or overnight pulse oximetry plus capnometry are used to detect nocturnal hypoventilation in early stage of respiratory failure. Ventilator strategy including non-invasive and invasive approach should be individualized for each patient. The author strongly believes that parents and family members are able to take care of their child at home if they are trained and educated effectively. A good team work with dedicated members is the key factor of success.

  12. Diaphragmatic dysfunction in mechanical ventilation.

    PubMed

    Haitsma, Jack J

    2011-04-01

    It has become clear from experimental data that prolonged mechanical ventilation can induce diaphragm dysfunction, also known as ventilator-induced diaphragm dysfunction. In this article we will discuss most recent understanding on ventilator-induced diaphragm dysfunction and data on diaphragm dysfunction in patients. Over the last year several studies confirmed the existence of diaphragm dysfunction in patients. Known atrophy pathways are activated in patients undergoing prolonged conventional ventilation resulting in muscle proteolysis and a decrease in myofiber content. The loss of diaphragm force is time-dependent, but current data do not distinguish between the role played by other factors involved in diaphragm dysfunction. Diaphragm dysfunction occurs in patients, especially when ventilated with controlled modes of ventilation that minimize diaphragm activity. Time on the ventilator seems to be one of the biggest risk factors resulting in difficulties in weaning patients and prolonging time on the ventilator. Future trials should investigate whether improved patient-ventilator synchrony can reduce ventilator-induced diaphragm dysfunction and decrease weaning failure.

  13. Ventilators for noninvasive ventilation to treat acute respiratory failure.

    PubMed

    Scala, Raffaele; Naldi, Mario

    2008-08-01

    The application of noninvasive ventilation (NIV) to treat acute respiratory failure has increased tremendously both inside and outside the intensive care unit. The choice of ventilator is crucial for success of NIV in the acute setting, because poor tolerance and excessive air leaks are significantly correlated with NIV failure. Patient-ventilator asynchrony and discomfort can occur if the physician or respiratory therapist fails to adequately set NIV to respond to the patient's ventilatory demand, so clinicians need to fully understood the ventilator's technical peculiarities (eg, efficiency of trigger and cycle systems, speed of pressurization, air-leak compensation, CO(2) rebreathing, reliability of fraction of inspired oxygen reading, monitoring accuracy). A wide range of ventilators of different complexity have been introduced into clinical practice to noninvasively support patients in acute respiratory failure, but the numerous commercially available ventilators (bi-level, intermediate, and intensive care unit ventilators) have substantial differences that can influence patient comfort, patient-ventilator interaction, and, thus, the chance of NIV clinical success. This report examines the most relevant aspects of the historical evolution, the equipment, and the acute-respiratory-failure clinical application of NIV ventilators.

  14. Partial Neuromuscular Blockade during Partial Ventilatory Support in Sedated Patients with High Tidal Volumes.

    PubMed

    Doorduin, Jonne; Nollet, Joeke L; Roesthuis, Lisanne H; van Hees, Hieronymus W H; Brochard, Laurent J; Sinderby, Christer A; van der Hoeven, Johannes G; Heunks, Leo M A

    2017-04-15

    Controlled mechanical ventilation is used to deliver lung-protective ventilation in patients with acute respiratory distress syndrome. Despite recognized benefits, such as preserved diaphragm activity, partial support ventilation modes may be incompatible with lung-protective ventilation due to high Vt and high transpulmonary pressure. As an alternative to high-dose sedatives and controlled mechanical ventilation, pharmacologically induced neuromechanical uncoupling of the diaphragm should facilitate lung-protective ventilation under partial support modes. To investigate whether partial neuromuscular blockade can facilitate lung-protective ventilation while maintaining diaphragm activity under partial ventilatory support. In a proof-of-concept study, we enrolled 10 patients with lung injury and a Vt greater than 8 ml/kg under pressure support ventilation (PSV) and under sedation. After baseline measurements, rocuronium administration was titrated to a target Vt of 6 ml/kg during neurally adjusted ventilatory assist (NAVA). Thereafter, patients were ventilated in PSV and NAVA under continuous rocuronium infusion for 2 hours. Respiratory parameters, hemodynamic parameters, and blood gas values were measured. Rocuronium titration resulted in significant declines of Vt (mean ± SEM, 9.3 ± 0.6 to 5.6 ± 0.2 ml/kg; P < 0.0001), transpulmonary pressure (26.7 ± 2.5 to 10.7 ± 1.2 cm H2O; P < 0.0001), and diaphragm electrical activity (17.4 ± 2.3 to 4.5 ± 0.7 μV; P < 0.0001), and could be maintained under continuous rocuronium infusion. During titration, pH decreased (7.42 ± 0.02 to 7.35 ± 0.02; P < 0.0001), and mean arterial blood pressure increased (84 ± 6 to 99 ± 6 mm Hg; P = 0.0004), as did heart rate (83 ± 7 to 93 ± 8 beats/min; P = 0.0004). Partial neuromuscular blockade facilitates lung-protective ventilation during partial ventilatory support, while maintaining diaphragm activity

  15. Pulmonary mechanics during mechanical ventilation.

    PubMed

    Henderson, William R; Sheel, A William

    2012-03-15

    The use of mechanical ventilation has become widespread in the management of hypoxic respiratory failure. Investigations of pulmonary mechanics in this clinical scenario have demonstrated that there are significant differences in compliance, resistance and gas flow when compared with normal subjects. This paper will review the mechanisms by which pulmonary mechanics are assessed in mechanically ventilated patients and will review how the data can be used for investigative research purposes as well as to inform rational ventilator management.

  16. [Jet ventilation in laryngotracheal surgery].

    PubMed

    Friedrich, G; Mausser, G; Gugatschka, M

    2008-12-01

    Conventional endotracheal intubation can be a limiting factor in endolaryngeal and endotracheal surgery. Tubeless jet ventilation can overcome this problem and provides an unlimited operation field to the surgeon. Since the development of first jet ventilation systems, many modifications have been performed and are used permanently in daily clinical routine. The aim of this work is to provide an overview of widely used jet ventilation systems and furthermore to list all advantages, as well as disadvantages of this technique in laryngotracheal surgery.

  17. 46 CFR 111.105-21 - Ventilation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Ventilation. 111.105-21 Section 111.105-21 Shipping... REQUIREMENTS Hazardous Locations § 111.105-21 Ventilation. A ventilation duct which ventilates a hazardous location has the classification of that location. Each fan for ventilation of a hazardous location must...

  18. 46 CFR 111.105-21 - Ventilation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Ventilation. 111.105-21 Section 111.105-21 Shipping... REQUIREMENTS Hazardous Locations § 111.105-21 Ventilation. A ventilation duct which ventilates a hazardous location has the classification of that location. Each fan for ventilation of a hazardous location must...

  19. 46 CFR 111.105-21 - Ventilation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Ventilation. 111.105-21 Section 111.105-21 Shipping... REQUIREMENTS Hazardous Locations § 111.105-21 Ventilation. A ventilation duct which ventilates a hazardous location has the classification of that location. Each fan for ventilation of a hazardous location must...

  20. Field measurement of ventilation rates.

    PubMed

    Persily, A K

    2016-02-01

    Ventilation rates have significant impacts on building energy use and indoor contaminant concentrations, making them key parameters in building performance. Ventilation rates have been measured in buildings for many decades, and there are mature measurement approaches available to researchers and others who need to know actual ventilation rates in buildings. Despite the fact that ventilation rates are critical in interpreting indoor concentration measurements, it is disconcerting how few Indoor Air Quality field studies measure ventilation rates or otherwise characterize the ventilation design of the study building(s). This paper summarizes parameters of interest in characterizing building ventilation, available methods for quantifying these parameters, and challenges in applying these methods to different types of buildings and ventilation systems. These parameters include whole-building air change rates, system outdoor air intake rates, and building infiltration rates. Tracer gas methods are reviewed as well as system airflow rate measurements using, for example, duct traverses. Several field studies of ventilation rates conducted over the past 75 years are described to highlight the approaches employed and the findings obtained.

  1. Ventilated Oscillatory Boundary Layers

    DTIC Science & Technology

    1993-02-01

    AD-A266 226IllII !i III ll11111 II •" Ventilated Oscillatory Boundary Layers 0 Daniel -. Conley Douglas L. I nman C 0 UM U U U U till 1% w 1% W" Z t...A SIGNIFICANT NUMBER OF PAGES WHICH DO NOT REPRODUCE LEGIBLY. VENlTILATiD SCIILLAORY BOUNDARY LAYERS Daniel C. C7onley DoL’laN L. . ... La olDla...Wave Crest ........ 5. Boundary Layer Development Under the Wave Trough W 6 . Laboratory Observations .................. ................ 7

  2. Laboratory and Industrial Ventilation

    NASA Technical Reports Server (NTRS)

    1972-01-01

    This handbook supplements the Facilities Engineering Handbook (NHB 7320.1) and provides additional policies and criteria for uniform application to ventilation systems. It expands basic requirements, provides additional design and construction guidance, and places emphasis on those design considerations which will provide for greater effectiveness in the use of these systems. The provisions of this handbook are applicable to all NASA field installations and the Jet Propulsion Laboratory. Since supply of this handbook is limited, abstracts of the portion or portions applicable to a given requirement will be made for the individual specific needs encountered rather than supplying copies of the handbook as has been past practice.

  3. Radioaerosol ventilation imaging in ventilator-dependent patients. Technical considerations

    SciTech Connect

    Vezina, W.; Chamberlain, M.; Vinitski, S.; King, M.; Nicholson, R.; Morgan, W.K.

    1985-11-01

    The differentiation of pulmonary embolism (PE) from regional ventilatory abnormalities accompanied by reduced perfusion requires contemporary perfusion and ventilation studies. Distinguishing these conditions in ventilator-dependent patients is aided by administering a Tc-99m aerosol to characterize regional ventilation, and by performing a conventional Tc-99m MAA perfusion study. The technique uses a simple in-house constructed apparatus. Simple photographic techniques suffice, but computer subtraction of perfusion from the combined perfusion-ventilation image renders interpretation easier if aerosol administration follows perfusion imaging. Multiple defects can be examined in a single study. Excluding normal or near-normal perfusion studies, PE was thought to be present in eight of 16 patients after perfusion imaging alone, but in only one of eight after added aerosol imaging. Angiography confirmed the diagnosis in that patient. Of the eight patients who had abnormal perfusion but were thought unlikely to have PE from the perfusion study alone, two had normal ventilation, and subsequently were shown to have PE by angiography. Because angiography was only performed on patients who were thought to have a high probability of PE on sequential perfusion-ventilation imaging, the true incidence of PE may have been higher. Aerosol ventilation imaging is a useful adjunct to perfusion imaging in patients on ventilators. It requires an efficient delivery system, particularly if aerosol administration follows perfusion imaging, as it does in this study.

  4. Nuclear factor-κB signaling contributes to mechanical ventilation-induced diaphragm weakness*.

    PubMed

    Smuder, Ashley J; Hudson, Matthew B; Nelson, W Bradley; Kavazis, Andreas N; Powers, Scott K

    2012-03-01

    Although mechanical ventilation is a life-saving measure for patients in respiratory failure, prolonged mechanical ventilation results in diaphragmatic weakness attributable to fiber atrophy and contractile dysfunction. Therefore, identifying the signaling pathways responsible for mechanical ventilation-induced diaphragmatic weakness is important. In this context, it is established that oxidative stress is required for mechanical ventilation-induced diaphragmatic weakness to occur. Numerous redox-sensitive signaling pathways exist in muscle including the transcription factor nuclear factor-κB. Although it has been suggested that nuclear factor-κB contributes to proteolytic signaling in inactivity-induced atrophy in locomotor muscles, the role that nuclear factor-κB plays in mechanical ventilation-induced diaphragmatic weakness is unknown. We tested the hypothesis that nuclear factor-κB activation plays a key signaling role in mechanical ventilation-induced diaphragmatic weakness and that oxidative stress is required for nuclear factor-κB activation. Cause and effect was determined by independently treating mechanically ventilated animals with either a specific nuclear factor-κB inhibitor (SN50) or a clinically relevant antioxidant (curcumin). Inhibition of nuclear factor-κB activity partially attenuated both mechanical ventilation-induced diaphragmatic atrophy and contractile dysfunction. Further, treatment with the antioxidant curcumin prevented mechanical ventilation-induced activation of nuclear factor-κB in the diaphragm and rescued the diaphragm from both mechanical ventilation-induced atrophy and contractile dysfunction. Collectively, these findings support the hypothesis that nuclear factor-κB activation plays a significant signaling role in mechanical ventilation-induced diaphragmatic weakness and that oxidative stress is an upstream activator of nuclear factor-κB. Finally, our results suggest that prevention of mechanical ventilation

  5. Fuselage ventilation under wind conditions

    NASA Technical Reports Server (NTRS)

    Stuart, J. W.

    1979-01-01

    To determine realistic fuselage ventilation rates for post-crash fires and full-scale fire tests, the effects on wind-about fuselage ventilation rate of various parameters were studied. The parameters investigated were fuselage size and shape, fuselage orientation and proximity to ground, fuselage-opening and location, and wind speed and direction.

  6. Transpired Air Collectors - Ventilation Preheating

    SciTech Connect

    Christensen, C.

    2006-06-22

    Many commercial and industrial buildings have high ventilation rates. Although all that fresh air is great for indoor air quality, heating it can be very expensive. This short (2-page) fact sheet describes a technology available to use solar energy to preheat ventilation air and dramatically reduce utility bills.

  7. Mechanical ventilation in abdominal surgery.

    PubMed

    Futier, E; Godet, T; Millot, A; Constantin, J-M; Jaber, S

    2014-01-01

    One of the key challenges in perioperative care is to reduce postoperative morbidity and mortality. Patients who develop postoperative morbidity but survive to leave hospital have often reduced functional independence and long-term survival. Mechanical ventilation provides a specific example that may help us to shift thinking from treatment to prevention of postoperative complications. Mechanical ventilation in patients undergoing surgery has long been considered only as a modality to ensure gas exchange while allowing maintenance of anesthesia with delivery of inhaled anesthetics. Evidence is accumulating, however, suggesting an association between intraoperative mechanical ventilation strategy and postoperative pulmonary function and clinical outcome in patients undergoing abdominal surgery. Non-protective ventilator settings, especially high tidal volume (VT) (>10-12mL/kg) and the use of very low level of positive end-expiratory pressure (PEEP) (PEEP<5cmH2O) or no PEEP, may cause alveolar overdistension and repetitive tidal recruitment leading to ventilator-associated lung injury in patients with healthy lungs. Stimulated by previous findings in patients with acute respiratory distress syndrome, the use of lower tidal volume ventilation is becoming increasingly more common in the operating room. However, lowering tidal volume, though important, is only part of the overall multifaceted approach of lung protective mechanical ventilation. In this review, we aimed at providing the most recent and relevant clinical evidence regarding the use of mechanical ventilation in patients undergoing abdominal surgery.

  8. Inhalation therapy in mechanical ventilation

    PubMed Central

    Maccari, Juçara Gasparetto; Teixeira, Cassiano; Gazzana, Marcelo Basso; Savi, Augusto; Dexheimer-Neto, Felippe Leopoldo; Knorst, Marli Maria

    2015-01-01

    Patients with obstructive lung disease often require ventilatory support via invasive or noninvasive mechanical ventilation, depending on the severity of the exacerbation. The use of inhaled bronchodilators can significantly reduce airway resistance, contributing to the improvement of respiratory mechanics and patient-ventilator synchrony. Although various studies have been published on this topic, little is known about the effectiveness of the bronchodilators routinely prescribed for patients on mechanical ventilation or about the deposition of those drugs throughout the lungs. The inhaled bronchodilators most commonly used in ICUs are beta adrenergic agonists and anticholinergics. Various factors might influence the effect of bronchodilators, including ventilation mode, position of the spacer in the circuit, tube size, formulation, drug dose, severity of the disease, and patient-ventilator synchrony. Knowledge of the pharmacological properties of bronchodilators and the appropriate techniques for their administration is fundamental to optimizing the treatment of these patients. PMID:26578139

  9. Evaluation of building ventilation systems

    SciTech Connect

    Hughes, R.T.; O'Brien, D.M.

    1986-04-01

    Over the past several years, NIOSH has responded to health hazard evaluation requests from workers in dozens of office environments. Typically, the employees have complained of headache, eye and upper respiratory tract irritation, dizziness, lethargy and the inability to concentrate. Most often inadequate ventilation has been blamed for these complaints. Of paramount importance in the evaluation and correction of these problems is an effective evaluation of the building's ventilation system. Heating, ventilating and air-conditioning conditions that can cause worker stresses include: migration of odors or chemical hazards between building areas; reentrainment of exhaust from building fume hoods or through heat wheels; buildup of microorganisms in the HVAC system components; and poor odor or environmental control due to insufficient fresh outdoor air or system heating or cooling malfunction. The purpose of this paper is to provide an overview of building ventilation systems, the ventilation problems associated with poorly designed or operating systems, and the methodology for effectively evaluating system performance.

  10. Difficult weaning from mechanical ventilation.

    PubMed

    Oh, T E

    1994-07-01

    Weaning from mechanical ventilation may be influenced by factors relating to equipment, techniques and procedures. Criteria to initiate weaning and predictors of weaning outcome are generally unreliable, but mechanical work of breathing, the tidal volume: frequency ratio and the inspiratory pressure: maximal inspiratory pressure ratio may anticipate those likely to fail weaning. The optimal weaning ventilatory mode is not known, but intermittent mandatory ventilation, pressure support ventilation, and continuous positive pressure ventilation are the most commonly used. The resistances of individual components of breathing circuits are extremely important. Blow-by heated humidifiers and ventilators which compensate for the impedances of their inspiratory demand valves impose clinically acceptable spontaneous breathing loads. Close monitoring, adequate respiratory muscle rest, attention to mineral deficiencies, nutrition and pulmonary hygiene are also important parts of the weaning process.

  11. Ventilator-induced diaphragmatic dysfunction.

    PubMed

    Petrof, Basil J; Jaber, Samir; Matecki, Stefan

    2010-02-01

    Diaphragmatic function is a major determinant of the ability to successfully wean patients from mechanical ventilation. There is increasing recognition of a condition termed ventilator-induced diaphragmatic dysfunction. The purpose of the present review is to present evidence that mechanical ventilation can itself be a cause of diaphragmatic dysfunction, to outline our current understanding of the cellular mechanisms responsible for this phenomenon, and to discuss the implications of recent research for future therapeutic strategies. Many critically ill patients demonstrate diaphragmatic weakness. A large body of evidence from animal models, and more limited data from humans, indicates that mechanical ventilation can cause muscle fiber injury and atrophy within the diaphragm. Current data support a complex underlying pathophysiology involving oxidative stress and the activation of several intracellular proteolytic pathways involved in degradation of the contractile apparatus. This includes the calpain, caspase, and ubiquitin-proteasome systems. In addition, there is a simultaneous downregulation of protein synthesis pathways. Studies in animal models suggest that future therapies may be able to specifically target these processes, whereas for the time being current preventive measures in humans are primarily based upon allowing persistent diaphragmatic activation during mechanical ventilation. Diaphragmatic dysfunction is common in mechanically ventilated patients and is a likely cause of weaning failure. Recently, there has been a great expansion in our knowledge of how mechanical ventilation can adversely affect diaphragmatic structure and function. Future studies need to better define the evolution and mechanistic basis for ventilator-induced diaphragmatic dysfunction in humans, in order to allow the development of mechanical ventilation strategies and pharmacologic agents that will decrease the incidence of ventilator-induced diaphragmatic dysfunction.

  12. Methanol partial oxidation reformer

    DOEpatents

    Ahmed, Shabbir; Kumar, Romesh; Krumpelt, Michael

    1999-01-01

    A partial oxidation reformer comprising a longitudinally extending chamber having a methanol, water and an air inlet and an outlet. An igniter mechanism is near the inlets for igniting a mixture of methanol and air, while a partial oxidation catalyst in the chamber is spaced from the inlets and converts methanol and oxygen to carbon dioxide and hydrogen. Controlling the oxygen to methanol mole ratio provides continuous slightly exothermic partial oxidation reactions of methanol and air producing hydrogen gas. The liquid is preferably injected in droplets having diameters less than 100 micrometers. The reformer is useful in a propulsion system for a vehicle which supplies a hydrogen-containing gas to the negative electrode of a fuel cell.

  13. Methanol partial oxidation reformer

    DOEpatents

    Ahmed, S.; Kumar, R.; Krumpelt, M.

    1999-08-17

    A partial oxidation reformer is described comprising a longitudinally extending chamber having a methanol, water and an air inlet and an outlet. An igniter mechanism is near the inlets for igniting a mixture of methanol and air, while a partial oxidation catalyst in the chamber is spaced from the inlets and converts methanol and oxygen to carbon dioxide and hydrogen. Controlling the oxygen to methanol mole ratio provides continuous slightly exothermic partial oxidation reactions of methanol and air producing hydrogen gas. The liquid is preferably injected in droplets having diameters less than 100 micrometers. The reformer is useful in a propulsion system for a vehicle which supplies a hydrogen-containing gas to the negative electrode of a fuel cell. 7 figs.

  14. Methanol partial oxidation reformer

    DOEpatents

    Ahmed, S.; Kumar, R.; Krumpelt, M.

    1999-08-24

    A partial oxidation reformer is described comprising a longitudinally extending chamber having a methanol, water and an air inlet and an outlet. An igniter mechanism is near the inlets for igniting a mixture of methanol and air, while a partial oxidation catalyst in the chamber is spaced from the inlets and converts methanol and oxygen to carbon dioxide and hydrogen. Controlling the oxygen to methanol mole ratio provides continuous slightly exothermic partial oxidation reactions of methanol and air producing hydrogen gas. The liquid is preferably injected in droplets having diameters less than 100 micrometers. The reformer is useful in a propulsion system for a vehicle which supplies a hydrogen-containing gas to the negative electrode of a fuel cell. 7 figs.

  15. Methanol partial oxidation reformer

    DOEpatents

    Ahmed, Shabbir; Kumar, Romesh; Krumpelt, Michael

    2001-01-01

    A partial oxidation reformer comprising a longitudinally extending chamber having a methanol, water and an air inlet and an outlet. An igniter mechanism is near the inlets for igniting a mixture of methanol and air, while a partial oxidation catalyst in the chamber is spaced from the inlets and converts methanol and oxygen to carbon dioxide and hydrogen. Controlling the oxygen to methanol mole ratio provides continuous slightly exothermic partial oxidation reactions of methanol and air producing hydrogen gas. The liquid is preferably injected in droplets having diameters less than 100 micrometers. The reformer is useful in a propulsion system for a vehicle which supplies a hydrogen-containing gas to the negative electrode of a fuel cell.

  16. Methanol partial oxidation reformer

    DOEpatents

    Ahmed, Shabbir; Kumar, Romesh; Krumpelt, Michael

    1999-01-01

    A partial oxidation reformer comprising a longitudinally extending chamber having a methanol, water and an air inlet and an outlet. An igniter mechanism is near the inlets for igniting a mixture of methanol and air, while a partial oxidation catalyst in the chamber is spaced from the inlets and converts methanol and oxygen to carbon dioxide and hydrogen. Controlling the oxygen to methanol mole ratio provides continuous slightly exothermic partial oxidation reactions of methanol and air producing hydrogen gas. The liquid is preferably injected in droplets having diameters less than 100 micrometers. The reformer is useful in a propulsion system for a vehicle which supplies a hydrogen-containing gas to the negative electrode of a fuel cell.

  17. Ventilation and respiratory mechanics.

    PubMed

    Sheel, Andrew William; Romer, Lee M

    2012-04-01

    During dynamic exercise, the healthy pulmonary system faces several major challenges, including decreases in mixed venous oxygen content and increases in mixed venous carbon dioxide. As such, the ventilatory demand is increased, while the rising cardiac output means that blood will have considerably less time in the pulmonary capillaries to accomplish gas exchange. Blood gas homeostasis must be accomplished by precise regulation of alveolar ventilation via medullary neural networks and sensory reflex mechanisms. It is equally important that cardiovascular and pulmonary system responses to exercise be precisely matched to the increase in metabolic requirements, and that the substantial gas transport needs of both respiratory and locomotor muscles be considered. Our article addresses each of these topics with emphasis on the healthy, young adult exercising in normoxia. We review recent evidence concerning how exercise hyperpnea influences sympathetic vasoconstrictor outflow and the effect this might have on the ability to perform muscular work. We also review sex-based differences in lung mechanics.

  18. Solar ventilation and tempering

    NASA Astrophysics Data System (ADS)

    Adámek, Karel; Pavlů, Miloš; Bandouch, Milan

    2014-08-01

    The paper presents basic information about solar panels, designed, realized and used for solar ventilation of rooms. Used method of numerical flow simulation gives good overview about warming and flowing of the air in several kinds of realized panels (window, facade, chimney). Yearlong measurements give a good base for calculations of economic return of invested capital. The operation of the system in transient period (spring, autumn) prolongs the period without classical heating of the room or building, in winter the classical heating is supported. In the summer period the system, furnished with chimney, can exhaust inner warm air together with necessary cooling of the system by gravity circulation, only. System needs not any invoiced energy source; it is supplied entirely by solar energy. Large building systems are supported by classical electric fan respectively.

  19. Cardiac gated ventilation

    SciTech Connect

    Hanson, C.W. III; Hoffman, E.A.

    1995-12-31

    There are several theoretic advantages to synchronizing positive pressure breaths with the cardiac cycle, including the potential for improving distribution of pulmonary and myocardial blood flow and enhancing cardiac output. The authors evaluated the effects of synchronizing respiration to the cardiac cycle using a programmable ventilator and electron beam CT (EBCT) scanning. The hearts of anesthetized dogs were imaged during cardiac gated respiration with a 50 msec scan aperture. Multi slice, short axis, dynamic image data sets spanning the apex to base of the left ventricle were evaluated to determine the volume of the left ventricular chamber at end-diastole and end-systole during apnea, systolic and diastolic cardiac gating. The authors observed an increase in cardiac output of up to 30% with inspiration gated to the systolic phase of the cardiac cycle in a non-failing model of the heart.

  20. Estimation of Lung Ventilation

    NASA Astrophysics Data System (ADS)

    Ding, Kai; Cao, Kunlin; Du, Kaifang; Amelon, Ryan; Christensen, Gary E.; Raghavan, Madhavan; Reinhardt, Joseph M.

    Since the primary function of the lung is gas exchange, ventilation can be interpreted as an index of lung function in addition to perfusion. Injury and disease processes can alter lung function on a global and/or a local level. MDCT can be used to acquire multiple static breath-hold CT images of the lung taken at different lung volumes, or with proper respiratory control, 4DCT images of the lung reconstructed at different respiratory phases. Image registration can be applied to this data to estimate a deformation field that transforms the lung from one volume configuration to the other. This deformation field can be analyzed to estimate local lung tissue expansion, calculate voxel-by-voxel intensity change, and make biomechanical measurements. The physiologic significance of the registration-based measures of respiratory function can be established by comparing to more conventional measurements, such as nuclear medicine or contrast wash-in/wash-out studies with CT or MR. An important emerging application of these methods is the detection of pulmonary function change in subjects undergoing radiation therapy (RT) for lung cancer. During RT, treatment is commonly limited to sub-therapeutic doses due to unintended toxicity to normal lung tissue. Measurement of pulmonary function may be useful as a planning tool during RT planning, may be useful for tracking the progression of toxicity to nearby normal tissue during RT, and can be used to evaluate the effectiveness of a treatment post-therapy. This chapter reviews the basic measures to estimate regional ventilation from image registration of CT images, the comparison of them to the existing golden standard and the application in radiation therapy.

  1. Ventilation/perfusion mismatch during lung aeration at birth.

    PubMed

    Lang, Justin A R; Pearson, James T; te Pas, Arjan B; Wallace, Megan J; Siew, Melissa L; Kitchen, Marcus J; Fouras, Andreas; Lewis, Robert A; Wheeler, Kevin I; Polglase, Graeme R; Shirai, Mikiyasu; Sonobe, Takashi; Hooper, Stuart B

    2014-09-01

    At birth, the transition to newborn life is triggered by lung aeration, which stimulates a large increase in pulmonary blood flow (PBF). Current theories predict that the increase in PBF is spatially related to ventilated lung regions as they aerate after birth. Using simultaneous phase-contrast X-ray imaging and angiography we investigated the spatial relationships between lung aeration and the increase in PBF after birth. Six near-term (30-day gestation) rabbits were delivered by caesarean section, intubated and an intravenous catheter inserted, before they were positioned for X-ray imaging. During imaging, iodine was injected before ventilation onset, after ventilation of the right lung only, and after ventilation of both lungs. Unilateral ventilation increased iodine levels entering both left and right pulmonary arteries (PAs) and significantly increased heart rate, iodine ejection per beat, diameters of both left and right PAs, and number of visible vessels in both lungs. Within the 6th intercostal space, the mean gray level (relative measure of iodine level) increased from 68.3 ± 11.6 and 70.3 ± 7.5%·s to 136.3 ± 22.6 and 136.3 ± 23.7%·s in the left and right PAs, respectively. No differences were observed between vessels in the left and right lungs, despite the left lung not initially being ventilated. The increase in PBF at birth is not spatially related to lung aeration allowing a large ventilation/perfusion mismatch, or pulmonary shunting, to occur in the partially aerated lung at birth.

  2. [Leak monitoring in noninvasive ventilation].

    PubMed

    Rabec, C A; Reybet-Degat, O; Bonniaud, P; Fanton, A; Camus, P

    2004-11-01

    Nasal mask ventilation has been shown to be effective, but outcomes do not always match expectations because of mouth leaks, patient-ventilator asynchrony, or decreased upper airway patency. These developments are detected when they lead ultimately to circuit leaks that lower the effectiveness of ventilation through pressure loss, poor inspiratory triggering, and prolonged inspiratory time. The quality of sleep is affected, and adverse effects and treatment intolerance may arise. A number of ways to detect leaks and their practical consequences are proposed in this article. We applied 310 leak-detection procedures to 177 patients who had disappointing clinical, gasometric, or polysomnographic outcomes of ventilation. The leak-detection procedures varied according to the type of ventilation and the supposed underlying pathophysiological mechanism. Significant leaks were detected in 132 patients (76%); therapeutic changes were then prescribed to optimize outcomes. We present a practical method to apply in patients with suboptimal ventilation outcomes. If leaks can be detected during treatment, the probable cause of treatment failure can sometimes be established and possible pathophysiological mechanisms better understood. With this knowledge, it may be possible to improve ventilation.

  3. Ventilator Associated Pneumonia in Children.

    PubMed

    Chang, Ivy; Schibler, Andreas

    2016-09-01

    Ventilator associated pneumonia (VAP) is a common complication in mechanically ventilated children and adults. There remains much controversy in the literature over the definition, treatment and prevention of VAP. The incidence of VAP is variable, depending on the definition used and can effect up to 12% of ventilated children. For the prevention and reduction of the incidence of VAP, ventilation care bundles are suggested, which include vigorous hand hygiene, head elevation and use of non-invasive ventilation strategies. Diagnosis is mainly based on the clinical presentation with a lung infection occurring after 48hours of mechanical ventilation requiring a change in ventilator settings (mainly increased oxygen requirement, a positive culture of a specimen taken preferentially using a sterile sampling technique either using a bronchoscope or a blind lavage of the airways). A new infiltrate on a chest X ray supports the diagnosis of VAP. For the treatment of VAP, initial broad-spectrum antibiotics should be used followed by a specific antibiotic therapy with a narrow target once the bacterium is confirmed.

  4. Respiratory dysfunction in ventilated patients: can inspiratory muscle training help?

    PubMed

    Bissett, B; Leditschke, I A; Paratz, J D; Boots, R J

    2012-03-01

    Respiratory muscle dysfunction is associated with prolonged and difficult weaning from mechanical ventilation. This dysfunction in ventilator-dependent patients is multifactorial: there is evidence that inspiratory muscle weakness is partially explained by disuse atrophy secondary to ventilation, and positive end-expiratory pressure can further reduce muscle strength by negatively shifting the length-tension curve of the diaphragm. Polyneuropathy is also likely to contribute to apparent muscle weakness in critically ill patients, and nutritional and pharmaceutical effects may further compound muscle weakness. Moreover, psychological influences, including anxiety, may contribute to difficulty in weaning. There is recent evidence that inspiratory muscle training is safe and feasible in selected ventilator-dependent patients, and that this training can reduce the weaning period and improve overall weaning success rates. Extrapolating from evidence in sports medicine, as well as the known effects of inspiratory muscle training in chronic lung disease, a theoretical model is proposed to describe how inspiratory muscle training enhances weaning and recovery from mechanical ventilation. Possible mechanisms include increased protein synthesis (both Type 1 and Type 2 muscle fibres), enhanced limb perfusion via dampening of a sympathetically-mediated metaboreflex, reduced lactate levels and modulation of the perception of exertion, resulting in less dyspnoea and enhanced exercise capacity.

  5. Subsurface Ventilation System Description Document

    SciTech Connect

    Eric Loros

    2001-07-25

    The Subsurface Ventilation System supports the construction and operation of the subsurface repository by providing air for personnel and equipment and temperature control for the underground areas. Although the system is located underground, some equipment and features may be housed or located above ground. The system ventilates the underground by providing ambient air from the surface throughout the subsurface development and emplacement areas. The system provides fresh air for a safe work environment and supports potential retrieval operations by ventilating and cooling emplacement drifts. The system maintains compliance within the limits established for approved air quality standards. The system maintains separate ventilation between the development and waste emplacement areas. The system shall remove a portion of the heat generated by the waste packages during preclosure to support thermal goals. The system provides temperature control by reducing drift temperature to support potential retrieval operations. The ventilation system has the capability to ventilate selected drifts during emplacement and retrieval operations. The Subsurface Facility System is the main interface with the Subsurface Ventilation System. The location of the ducting, seals, filters, fans, emplacement doors, regulators, and electronic controls are within the envelope created by the Ground Control System in the Subsurface Facility System. The Subsurface Ventilation System also interfaces with the Subsurface Electrical System for power, the Monitored Geologic Repository Operations Monitoring and Control System to ensure proper and safe operation, the Safeguards and Security System for access to the emplacement drifts, the Subsurface Fire Protection System for fire safety, the Emplacement Drift System for repository performance, and the Backfill Emplacement and Subsurface Excavation Systems to support ventilation needs.

  6. Subsurface Ventilation System Description Document

    SciTech Connect

    2000-10-12

    The Subsurface Ventilation System supports the construction and operation of the subsurface repository by providing air for personnel and equipment and temperature control for the underground areas. Although the system is located underground, some equipment and features may be housed or located above ground. The system ventilates the underground by providing ambient air from the surface throughout the subsurface development and emplacement areas. The system provides fresh air for a safe work environment and supports potential retrieval operations by ventilating and cooling emplacement drifts. The system maintains compliance within the limits established for approved air quality standards. The system maintains separate ventilation between the development and waste emplacement areas. The system shall remove a portion of the heat generated by the waste packages during preclosure to support thermal goals. The system provides temperature control by reducing drift temperature to support potential retrieval operations. The ventilation system has the capability to ventilate selected drifts during emplacement and retrieval operations. The Subsurface Facility System is the main interface with the Subsurface Ventilation System. The location of the ducting, seals, filters, fans, emplacement doors, regulators, and electronic controls are within the envelope created by the Ground Control System in the Subsurface Facility System. The Subsurface Ventilation System also interfaces with the Subsurface Electrical System for power, the Monitored Geologic Repository Operations Monitoring and Control System to ensure proper and safe operation, the Safeguards and Security System for access to the emplacement drifts, the Subsurface Fire Protection System for fire safety, the Emplacement Drift System for repository performance, and the Backfill Emplacement and Subsurface Excavation Systems to support ventilation needs.

  7. 6. VIEW LOOKING SOUTHEAST AT VENTILATION EQUIPMENT IN SOUTH VENTILATION ...

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

    6. VIEW LOOKING SOUTHEAST AT VENTILATION EQUIPMENT IN SOUTH VENTILATION HOUSE. THIS AIR CONDITIONING SYSTEM WAS INSTALLED BY PARKS-CRAMER COMPANY OF FITCHBURG, MASSACHUSETTS WHEN THE MILL WAS CONSTRUCTED IN 1923-24. ONE AIR WASHER AND FAN ROOM EXTERIOR IS VISIBLE ON THE RIGHT. THE DUCTS FROM BOTH FAN ROOMS (CURVED METAL STRUCTURES AT CENTER AND LEFT OF PHOTO) ARE CONNECTED TO A COMMON AIR SHAFT. - Stark Mill, 117 Corinth Road, Hogansville, Troup County, GA

  8. Effects of expiratory rib-cage compression on oxygenation, ventilation, and airway-secretion removal in patients receiving mechanical ventilation.

    PubMed

    Unoki, Takeshi; Kawasaki, Yuri; Mizutani, Taro; Fujino, Yoko; Yanagisawa, Yaeko; Ishimatsu, Shinichi; Tamura, Fumiko; Toyooka, Hidenori

    2005-11-01

    Expiratory rib-cage compression, a chest physiotherapy technique, is well known as the "squeezing" technique in Japan. To determine the effects of rib-cage compression on airway-secretion removal, oxygenation, and ventilation in patients receiving mechanical ventilation. An intensive care unit of an emergency and critical care center at a tertiary-care teaching hospital in Tokyo, Japan. Thirty-one intubated, mechanically ventilated patients in an intensive care unit were studied in a randomized, crossover trial. The patients received endotracheal suctioning with or without rib-cage compression, with a minimum 3-hour interval between the 2 interventions. Rib-cage compression was performed for 5 min before endotracheal suctioning. Arterial blood gas and respiratory mechanics were measured 5 min before endotracheal suctioning (baseline) and 25 min after suctioning. The 2 measurement periods were carried out on the same day. There were no significant differences in the ratio of arterial partial pressure of oxygen to fraction of inspired oxygen, P(aCO2), or dynamic compliance of the respiratory system between the 2 periods (before and after endotracheal suctioning). Moreover, there were no significant differences in airway-secretion removal between the 2 periods. This study suggests that rib-cage compression prior to endotracheal suctioning does not improve airway-secretion removal, oxygenation, or ventilation after endotracheal suctioning in this unselected population of mechanically ventilated patients.

  9. Preoperational test report, vent building ventilation system

    SciTech Connect

    Clifton, F.T.

    1997-11-04

    This represents a preoperational test report for Vent Building Ventilation Systems, Project W-030. Project W-030 provides a ventilation upgrade for the four Aging Waste Facility tanks. The system provides Heating, Ventilation, and Air Conditioning (HVAC) for the W-030 Ventilation Building. The tests verify correct system operation and correct indications displayed by the central Monitor and Control System.

  10. 30 CFR 57.8520 - Ventilation plan.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Ventilation plan. 57.8520 Section 57.8520... SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Ventilation Underground Only § 57.8520 Ventilation plan. A plan of the mine ventilation system shall be set out by...

  11. 24 CFR 3285.505 - Crawlspace ventilation.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 24 Housing and Urban Development 5 2011-04-01 2011-04-01 false Crawlspace ventilation. 3285.505... ventilation. (a) A crawlspace with skirting must be provided with ventilation openings. The minimum net area of ventilation openings must not be less than one square foot (ft.2) for every 150 square feet...

  12. 24 CFR 3285.505 - Crawlspace ventilation.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 24 Housing and Urban Development 5 2014-04-01 2014-04-01 false Crawlspace ventilation. 3285.505... ventilation. (a) A crawlspace with skirting must be provided with ventilation openings. The minimum net area of ventilation openings must not be less than one square foot (ft.2) for every 150 square feet...

  13. 30 CFR 57.8520 - Ventilation plan.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Ventilation plan. 57.8520 Section 57.8520... Underground Only § 57.8520 Ventilation plan. A plan of the mine ventilation system shall be set out by the... ventilation plan or revisions thereto shall be submitted to the District Manager for review and comments...

  14. 30 CFR 57.8520 - Ventilation plan.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Ventilation plan. 57.8520 Section 57.8520... Underground Only § 57.8520 Ventilation plan. A plan of the mine ventilation system shall be set out by the... ventilation plan or revisions thereto shall be submitted to the District Manager for review and comments...

  15. Preoperational test, vent building ventilation system

    SciTech Connect

    Clifton, F.T., Westinghouse Hanford

    1996-08-20

    Preoperational Test Procedure for Vent Building Ventilation System, Project W-030. Project W-030 provides a ventilation upgrade for the four Aging Waste Facility tanks. The Vent Building ventilation system provides ventilation, heating, cooling, and zone confinement control for the W-030 Project Vent Building. The tests verify correct System operation and correct indications displayed by the central Monitor and Control system.

  16. 46 CFR 168.15-50 - Ventilation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Ventilation. 168.15-50 Section 168.15-50 Shipping COAST... Accommodations § 168.15-50 Ventilation. (a) All quarters must be adequately ventilated in a manner suitable to the purpose of the space and route of the vessel. (b) When mechanical ventilation is provided...

  17. 46 CFR 194.20-5 - Ventilation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Ventilation. 194.20-5 Section 194.20-5 Shipping COAST... Ventilation. (a) Chemical storerooms shall be equipped with a power ventilation system of exhaust type. The... based upon the volume of the compartment. (1) Power ventilation units shall have nonsparking...

  18. 33 CFR 175.201 - Ventilation.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Ventilation. 175.201 Section 175... SAFETY EQUIPMENT REQUIREMENTS Ventilation § 175.201 Ventilation. No person may operate a boat built after... unless it is equipped with an operable ventilation system that meets the requirements of 33 CFR...

  19. 33 CFR 175.201 - Ventilation.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Ventilation. 175.201 Section 175... SAFETY EQUIPMENT REQUIREMENTS Ventilation § 175.201 Ventilation. No person may operate a boat built after... unless it is equipped with an operable ventilation system that meets the requirements of 33 CFR...

  20. 24 CFR 3285.505 - Crawlspace ventilation.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 24 Housing and Urban Development 5 2013-04-01 2013-04-01 false Crawlspace ventilation. 3285.505... ventilation. (a) A crawlspace with skirting must be provided with ventilation openings. The minimum net area of ventilation openings must not be less than one square foot (ft.2) for every 150 square feet...

  1. 33 CFR 175.201 - Ventilation.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Ventilation. 175.201 Section 175... SAFETY EQUIPMENT REQUIREMENTS Ventilation § 175.201 Ventilation. No person may operate a boat built after... unless it is equipped with an operable ventilation system that meets the requirements of 33 CFR...

  2. 46 CFR 168.15-50 - Ventilation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Ventilation. 168.15-50 Section 168.15-50 Shipping COAST... Accommodations § 168.15-50 Ventilation. (a) All quarters must be adequately ventilated in a manner suitable to the purpose of the space and route of the vessel. (b) When mechanical ventilation is provided...

  3. 46 CFR 194.20-5 - Ventilation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Ventilation. 194.20-5 Section 194.20-5 Shipping COAST... Ventilation. (a) Chemical storerooms shall be equipped with a power ventilation system of exhaust type. The... based upon the volume of the compartment. (1) Power ventilation units shall have nonsparking...

  4. 46 CFR 168.15-50 - Ventilation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Accommodations § 168.15-50 Ventilation. (a) All quarters must be adequately ventilated in a manner suitable to the purpose of the space and route of the vessel. (b) When mechanical ventilation is provided for... 46 Shipping 7 2010-10-01 2010-10-01 false Ventilation. 168.15-50 Section 168.15-50 Shipping...

  5. Physiological Effects of Positive Pressure Ventilation.

    DTIC Science & Technology

    1992-05-01

    in the ventilated patient and increase proportionally with the length of time Ventilation 43 mechanical ventilation is employed. Major infection ... sources are contributed to repeated breaks in the ventilator circuit and aspiration of gastric contents. There appears to be a positive correlation with

  6. 46 CFR 111.103-1 - Power ventilation systems except machinery space ventilation systems.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Power ventilation systems except machinery space ventilation systems. 111.103-1 Section 111.103-1 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... Power ventilation systems except machinery space ventilation systems. Each power ventilation system...

  7. 46 CFR 111.103-1 - Power ventilation systems except machinery space ventilation systems.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Power ventilation systems except machinery space ventilation systems. 111.103-1 Section 111.103-1 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... Power ventilation systems except machinery space ventilation systems. Each power ventilation system...

  8. Equivalence in Ventilation and Indoor Air Quality

    SciTech Connect

    Sherman, Max; Walker, Iain; Logue, Jennifer

    2011-08-01

    We ventilate buildings to provide acceptable indoor air quality (IAQ). Ventilation standards (such as American Society of Heating, Refrigerating, and Air-Conditioning Enginners [ASHRAE] Standard 62) specify minimum ventilation rates without taking into account the impact of those rates on IAQ. Innovative ventilation management is often a desirable element of reducing energy consumption or improving IAQ or comfort. Variable ventilation is one innovative strategy. To use variable ventilation in a way that meets standards, it is necessary to have a method for determining equivalence in terms of either ventilation or indoor air quality. This study develops methods to calculate either equivalent ventilation or equivalent IAQ. We demonstrate that equivalent ventilation can be used as the basis for dynamic ventilation control, reducing peak load and infiltration of outdoor contaminants. We also show that equivalent IAQ could allow some contaminants to exceed current standards if other contaminants are more stringently controlled.

  9. Basic concepts in mechanical ventilation.

    PubMed

    Carbery, Catherine

    2008-03-01

    Mechanical ventilatory support is a major component of the clinical management of critically ill patients admitted into intensive care. Closely linked with the developments within critical care medicine, the use of ventilatory support has been increasing since the polio epidemics in the 1950s (Lassen 1953). Initially used to provide controlled mandatory ventilation, today with advances in technology, most mechanical ventilators are triggered by the patient, increasing the awareness of the complexity of patient/ventilator interaction (Tobin 1994). Though ventilator appearance and design may have changed quite significantly and the variety of options for support extensive, the basic concepts of mechanical ventilatory support of the critically ill patient remains unchanged. This paper aims to outline these concepts so as to gain a better understanding of mechanical ventilatory support.

  10. Mechanical ventilation in the home.

    PubMed

    Make, B J; Gilmartin, M E

    1990-07-01

    Despite advances in the application of mechanical ventilation as a short-term, life-saving technique, intensive care units are increasingly faced with patients who cannot be weaned from ventilatory assistance and who require mechanical ventilation as a long-term, life-supporting necessity. Because of limited resources in health care facilities for the management of chronic ventilator-assisted individuals, home care has become an important option. With careful selection of appropriate candidates, home care for ventilator-assisted individuals can result in not only decreased respiratory symptoms, reduction in hospitalization, and improved physiologic measures, but also an improved quality of life with substantial survival and a reduction in the costs of medical care.

  11. Implications of natural occlusion of ventilated racks on ammonia and sanitation practices.

    PubMed

    Creamer, Michelle A; Petty, Joann; Martin, Tara; Bergdall, Valerie; Hickman-Davis, Judy M

    2014-03-01

    Examination of ventilated rat racks prior to semiannual sanitation revealed silicone nozzles and ventilation ports that were partially or completely occluded with granular debris. We subsequently sought to document performance standards for rack sanitation and investigate the effect of ventilation port occlusion on rack function and animal husbandry practices. We hypothesized that individually ventilated cages with occluded airflow would require more frequent cage changes, comparable to those for static cages (that is, every 3 to 4 d). Sprague-Dawley rats were housed under one of 4 conditions: no airflow occlusion, occluded air-supply inlet, occluded air-exhaust outlet, and occlusion of both inlet and outlet. Cages were changed when daily ammonia concentration exceeded 20 ppm or after 14 d had elapsed. Most cages with unoccluded or partial airflow occlusion remained below the 20 ppm limit until day 12 or 13. Cages with occlusion of both inlet and outlet exceeded 20 ppm ammonia by as early as day 5. Airflow was significantly lower in cages with occlusion of both inlet and outlet airflow. Weekly inspection revealed that occlusion of ventilation ports was detectable by 3 mo after semiannual sanitation. This study demonstrates that silicone nozzles should be removed prior to rack sanitation to improve the effectiveness of cleaning ventilation ports and nozzles. While the rack is in use, silicone nozzles and ventilation ports should be inspected regularly to identify occlusion that is likely to diminish environmental quality in the cage. Intracage ammonia levels are significantly higher when both inlet and outlet airflow are occluded.

  12. Partial Tonsillectomy.

    PubMed

    Wong, Kevin; Levi, Jessica R

    2017-03-01

    Evaluate the content and readability of health information regarding partial tonsillectomy. A web search was performed using the term partial tonsillectomy in Google, Yahoo!, and Bing. The first 50 websites from each search were evaluated using HONcode standards for quality and content. Readability was assessed using the Flesch-Kincaid Grade Level (FKGL), Flesch Reading Ease, Gunning-Fog Index, Coleman-Liau Index, Automated Readability Index, and SMOG score. The Freeman-Halton extension of Fisher's exact test was used to compare categorical differences between engines. Less than half of the websites mentioned patient eligibility criteria (43.3%), referenced peer-reviewed literature (43.3%), or provided a procedure description (46.7%). Twenty-two websites (14.7%) were unrelated to partial tonsillectomy, and over half contained advertisements (52%). These finding were consistent across search engines and search terms. The mean FKGL was 11.6 ± 0.11, Gunning-Fog Index was 15.1 ± 0.13, Coleman-Liau Index was 14.6 ± 0.11, ARI was 12.9 ± 0.13, and SMOG grade was 14.0 ± 0.1. All readability levels exceeded the abilities of the average American adult. Current online information regarding partial tonsillectomy may not provide adequate information and may be written at a level too difficult for the average adult reader.

  13. Ventilation Model and Analysis Report

    SciTech Connect

    V. Chipman

    2003-07-18

    This model and analysis report develops, validates, and implements a conceptual model for heat transfer in and around a ventilated emplacement drift. This conceptual model includes thermal radiation between the waste package and the drift wall, convection from the waste package and drift wall surfaces into the flowing air, and conduction in the surrounding host rock. These heat transfer processes are coupled and vary both temporally and spatially, so numerical and analytical methods are used to implement the mathematical equations which describe the conceptual model. These numerical and analytical methods predict the transient response of the system, at the drift scale, in terms of spatially varying temperatures and ventilation efficiencies. The ventilation efficiency describes the effectiveness of the ventilation process in removing radionuclide decay heat from the drift environment. An alternative conceptual model is also developed which evaluates the influence of water and water vapor mass transport on the ventilation efficiency. These effects are described using analytical methods which bound the contribution of latent heat to the system, quantify the effects of varying degrees of host rock saturation (and hence host rock thermal conductivity) on the ventilation efficiency, and evaluate the effects of vapor and enhanced vapor diffusion on the host rock thermal conductivity.

  14. Partial Derivative Fitted Taylor Expansion: An efficient method for calculating gas-liquid equilibria in atmospheric aerosol particles: 1. Inorganic compounds

    NASA Astrophysics Data System (ADS)

    Topping, David; Lowe, Douglas; McFiggans, Gordon

    2009-02-01

    Parameterizations for calculating the equilibrium vapor pressure of the semivolatile inorganic gases, HNO3, HCl, and NH3, above an aqueous aerosol are presented. The hybrid Partial Derivative Fitted Taylor Expansion (PD-FiTE) approach uses optimized model parameters describing the interaction between different inorganic ions, resulting in comparable computational performance with existing reduced methods while remaining accurate. Comparisons with the most accurate inorganic activity coefficient model available indicate that PD-FiTE performs very well over the parameterization space of the system H+-NH4+-Na+-SO42--HSO4--NO3--Cl- at 298.15 K. The linear additive framework allows the inclusion of further species. However, including the ability to describe the interaction between inorganic and organic components will be presented in a future publication. Coupling PD-FiTE to a coupled box model of gaseous chemistry and aerosol microphysics in a test case investigating marine aerosol passing through a polluted environment demonstrates its robustness and ability to capture fine details of important phenomena such as the outgassing of HCl in response to HNO3 uptake by sea-salt particles.

  15. Argonne Fuel Cycle Facility ventilation system -- modeling and results

    SciTech Connect

    Mohr, D.; Feldman, E.E.; Danielson, W.F.

    1995-02-01

    This paper describes an integrated study of the Argonne-West Fuel Cycle Facility (FCF) interconnected ventilation systems during various operations. Analyses and test results include first a nominal condition reflecting balanced pressures and flows followed by several infrequent and off-normal scenarios. This effort is the first study of the FCF ventilation systems as an integrated network wherein the hydraulic effects of all major air systems have been analyzed and tested. The FCF building consists of many interconnected regions in which nuclear fuel is handled, transported and reprocessed. The ventilation systems comprise a large number of ducts, fans, dampers, and filters which together must provide clean, properly conditioned air to the worker occupied spaces of the facility while preventing the spread of airborne radioactive materials to clean am-as or the atmosphere. This objective is achieved by keeping the FCF building at a partial vacuum in which the contaminated areas are kept at lower pressures than the other worker occupied spaces. The ventilation systems of FCF and the EBR-II reactor are analyzed as an integrated totality, as demonstrated. We then developed the network model shown in Fig. 2 for the TORAC code. The scope of this study was to assess the measured results from the acceptance/flow balancing testing and to predict the effects of power failures, hatch and door openings, single-failure faulted conditions, EBR-II isolation, and other infrequent operations. The studies show that the FCF ventilation systems am very controllable and remain stable following off-normal events. In addition, the FCF ventilation system complex is essentially immune to reverse flows and spread of contamination to clean areas during normal and off-normal operation.

  16. Ventilator risk management using a programmed monitor.

    PubMed

    Silvern, D A; Gupte, P M

    1989-01-01

    A computer program was written to improve quality control and risk management of patients on ventilators. The software was designed to run on the new-generation Spacelabs PC Monitor interfaced to the Puritan-Bennett 7200a ventilator. Before the program allows connection of the ventilator to a patient, the ventilator is polled for initial hardware status, alarm statuses and alarm limit settings. If there are no hardware failures, alarm violations, or improperly set alarm limits, the program prompts the clinician to connect the ventilator to the patient. Polling is done periodically after patient ventilation begins, and patient data, alarm conditions, or changes to the ventilator settings are automatically written to disk. In addition, real-time data can be displayed at any time during the ventilation session by using a set of touch-screen options. After the ventilation session is complete, the clinician can print the final report in hard copy or to disk.

  17. Inspiratory work and response times of a modified pediatric volume ventilator during synchronized intermittent mandatory ventilation and pressure support ventilation.

    PubMed

    Martin, L D; Rafferty, J F; Wetzel, R C; Gioia, F R

    1989-12-01

    Volume ventilation by demand flow ventilators significantly increases work of breathing during inspiration. Although various ventilator modifications and different modes of ventilation have been developed, there have been few studies regarding imposed work of breathing in infants and children. This study was designed to evaluate several modifications of a commercially available demand flow ventilator designed to shorten response time (tr) and decrease the imposed work (Wi) involved in opening the demand valve. Minimum withdrawal volume (Vmin), maximum negative pressure (P mneg), and tr were measured. Wi was defined as the product of Vmin and P mneg. Seven Siemens Servo 900C ventilators were tested under 16 different trial conditions with four variables: 1) mode of ventilation (synchronized intermittent mandatory ventilation [SIMV] vs. pressure support ventilation [PSV]); 2) caliber of circuit tubing (adult vs. pediatric); 3) location of airway pressure monitor (distal vs. proximal); and 4) ventilator trigger sensitivity (0 cm H2O--high vs. -2 cm H2O--low). Vmin, Pmneg, and Wi were all decreased (P less than .05) while tr was unaffected by changing ventilator trigger sensitivity from low to high. Wi was decreased by pediatric tubing and proximal airway pressure monitoring only when low trigger sensitivity was used. PSV and proximal airway monitoring shortened tr. The authors conclude that the use of pediatric circuit tubing and proximal airway pressure monitoring with a Siemens Servo 900C ventilator significantly improved ventilator performance.

  18. Residential ventilation standards scoping study

    SciTech Connect

    McKone, Thomas E.; Sherman, Max H.

    2003-10-01

    The goals of this scoping study are to identify research needed to develop improved ventilation standards for California's Title 24 Building Energy Efficiency Standards. The 2008 Title 24 Standards are the primary target for the outcome of this research, but this scoping study is not limited to that timeframe. We prepared this scoping study to provide the California Energy Commission with broad and flexible options for developing a research plan to advance the standards. This document presents the findings of a scoping study commissioned by the Public Interest Energy Research (PIER) program of the California Energy Commission to determine what research is necessary to develop new residential ventilation requirements for California. This study is one of three companion efforts needed to complete the job of determining the ventilation needs of California residences, determining the bases for setting residential ventilation requirements, and determining appropriate ventilation technologies to meet these needs and requirements in an energy efficient manner. Rather than providing research results, this scoping study identifies important research questions along with the level of effort necessary to address these questions and the costs, risks, and benefits of pursuing alternative research questions. In approaching these questions and corresponding levels of effort, feasibility and timing were important considerations. The Commission has specified Summer 2005 as the latest date for completing this research in time to update the 2008 version of California's Energy Code (Title 24).

  19. Surfactant-Induced Ordering and Wetting Transitions of Droplets of Thermotropic Liquid Crystals “Caged” Inside Partially Filled Polymeric Capsules

    PubMed Central

    2015-01-01

    We report a study of the wetting and ordering of thermotropic liquid crystal (LC) droplets that are trapped (or “caged”) within micrometer-sized cationic polymeric microcapsules dispersed in aqueous solutions of surfactants. When they were initially dispersed in water, we observed caged, nearly spherical droplets of E7, a nematic LC mixture, to occupy ∼40% of the interior volume of the polymeric capsules [diameter of 6.7 ± 0.3 μm, formed via covalent layer-by-layer assembly of branched polyethylenimine and poly(2-vinyl-4,4-dimethylazlactone)] and to contact the interior surface of the capsule wall at an angle of ∼157 ± 11°. The internal ordering of LC within the droplets corresponded to the so-called bipolar configuration (distorted by contact with the capsule walls). While the effects of dodecyltrimethylammonium bromide (DTAB) and sodium dodecyl sulfate (SDS) on the internal ordering of “free” LC droplets are similar, we observed the two surfactants to trigger strikingly different wetting and configurational transitions when LC droplets were caged within polymeric capsules. Specifically, upon addition of SDS to the aqueous phase, we observed the contact angles (θ) of caged LC on the interior surface of the capsule to decrease, resulting in a progression of complex droplet shapes, including lenses (θ ≈ 130 ± 10°), hemispheres (θ ≈ 89 ± 5°), and concave hemispheres (θ < 85°). The wetting transitions induced by SDS also resulted in changes in the internal ordering of the LC to yield states topologically equivalent to axial and radial configurations. Although topologically equivalent to free droplets, the contributions that surface anchoring, LC elasticity, and topological defects make to the free energy of caged LC droplets differ from those of free droplets. Overall, these results and others reported herein lead us to conclude that caged LC droplets offer a platform for new designs of LC-droplet-based responsive soft matter that cannot

  20. Density and sound speed measurements on model basalt (An-Di-Hd) liquids at one bar: New constraints on the partial molar volume and compressibility of the FeO component

    NASA Astrophysics Data System (ADS)

    Guo, Xuan; Lange, Rebecca A.; Ai, Yuhui

    2014-02-01

    Density and sound speed measurements were obtained over a wide range of temperature for three model basalt liquids in the An-Di-Hd (CaAl2Si2O8-CaMgSi2O6-CaFeSi2O6) system. High-temperature (1585-1838 K) double-bob density measurements were combined with low-temperature (943-930 K) measurements at the limiting fictive temperature for each sample to provide liquid volume data over a temperature interval of ∼900 K. In addition, relaxed sound speeds were obtained with a frequency sweep acoustic interferometer from 1665-1876 K. An ideal mixing model for molar volume, thermal expansivity, and isothermal compressibility recovers the new data from this study and leads to the following fitted values (±2σ) at 1723 K for VbarFeO (12.86±0.32 cm/mol), ∂VbarFeO/∂T((3.69±1.16)×10-3 cm/mol-K) and βbarT,FeO((4.72±0.46)×10-2 GPa). These volumetric properties for the FeO component are estimated to reflect Fe2+ in an average coordination of 5.7 (±0.2), based on the relationship between VbarFeO and Fe2+ coordination derived by a comparison to mineral molar volumes (Guo et al., 2013). Application of these volumetric data to a calculation of the pressure dependence of the Fe-Mg exchange reaction between orthopyroxene and basaltic liquid results in a small decrease in Fe-MgKD with pressure. In contrast, partial melting experiments of peridotite show a small increase in Fe-MgKD(opx-liq) with pressure (e.g., Walter, 1998). This difference in the pressure dependence is proposed to reflect the role of alkalis in reducing the average coordination number of Fe2+ toward five compared to the alkali-free model basalt compositions in this study, thus changing the volume and compressibility of the FeO liquid component. The results from this study may be most appropriately applied to lunar basalts, which are impoverished in alkalis.

  1. Automated mechanical ventilation: adapting decision making to different disease states.

    PubMed

    Lozano-Zahonero, S; Gottlieb, D; Haberthür, C; Guttmann, J; Möller, K

    2011-03-01

    The purpose of the present study is to introduce a novel methodology for adapting and upgrading decision-making strategies concerning mechanical ventilation with respect to different disease states into our fuzzy-based expert system, AUTOPILOT-BT. The special features are: (1) Extraction of clinical knowledge in analogy to the daily routine. (2) An automated process to obtain the required information and to create fuzzy sets. (3) The controller employs the derived fuzzy rules to achieve the desired ventilation status. For demonstration this study focuses exclusively on the control of arterial CO(2) partial pressure (p(a)CO(2)). Clinical knowledge from 61 anesthesiologists was acquired using a questionnaire from which different disease-specific fuzzy sets were generated to control p(a)CO(2). For both, patients with healthy lung and with acute respiratory distress syndrome (ARDS) the fuzzy sets show different shapes. The fuzzy set "normal", i.e., "target p(a)CO(2) area", ranges from 35 to 39 mmHg for healthy lungs and from 39 to 43 mmHg for ARDS lungs. With the new fuzzy sets our AUTOPILOT-BT reaches the target p(a)CO(2) within maximal three consecutive changes of ventilator settings. Thus, clinical knowledge can be extended, updated, and the resulting mechanical ventilation therapies can be individually adapted, analyzed, and evaluated.

  2. [Nasopharyngeal myiasis during mechanical ventilation].

    PubMed

    Yoshitomi, A; Sato, A; Suda, T; Chida, K

    1997-12-01

    We report a case of myiasis caused by Phaenicia sericata during mechanical ventilation. An 86-year-old woman with bronchiectasis was admitted to our hospital with severe respiratory failure. Treatment with mechanical ventilation and sedatives was initiated. On the 10th day of hospitalization, about 20 white larvae were found in the patient's oral or nasal cavities. The larvae were removed and identified as Phaenicia sericata. No mucosal injury was found in the patient's oral or nasal cavity by endoscopic examination. The patient died of multiple organ failure caused by sepsis that had no association with myiasis. From the clinical course and the fly's life cycle, it is considered that the fly laid eggs in the patient's oral or nasal cavity while she was sedated during mechanical ventilation. Myiasis can occur even in a hospital.

  3. Assisted mechanical ventilation: the future is now!

    PubMed

    Kacmarek, Robert M; Pirrone, Massimiliano; Berra, Lorenzo

    2015-07-29

    Assisted ventilation is a highly complex process that requires an intimate interaction between the ventilator and the patient. The complexity of this form of ventilation is frequently underappreciated by the bedside clinician. In assisted mechanical ventilation, regardless of the specific mode, the ventilator's gas delivery pattern and the patient's breathing pattern must match near perfectly or asynchrony between the patient and the ventilator occurs. Asynchrony can be categorized into four general types: flow asynchrony; trigger asynchrony; cycle asynchrony; and mode asynchrony. In an article recently published in BMC Anesthesiology, Hodane et al. have demonstrated reduced asynchrony during assisted ventilation with Neurally Adjusted Ventilatory Assist (NAVA) as compared to pressure support ventilation (PSV). These findings add to the growing volume of data indicating that modes of ventilation that provide proportional assistance to ventilation - e.g., NAVA and Proportional Assist Ventilation (PAV) - markedly reduce asynchrony. As it becomes more accepted that the respiratory center of the patient in most circumstances is the most appropriate determinant of ventilatory pattern and as the negative outcome effects of patient-ventilator asynchrony become ever more recognized, we can expect NAVA and PAV to become the preferred modes of assisted ventilation!

  4. Macromolecular liquids

    SciTech Connect

    Safinya, C.R.; Safran, S.A. ); Pincus, P.A. )

    1990-01-01

    Liquids include a broad range of material systems which are of high scientific and technological interest. Generally speaking, these are partially ordered or disordered phases where the individual molecular species have organized themselves on length scales which are larger than simple fluids, typically between 10 Angstroms and several microns. The specific systems reported on in this book include membranes, microemulsions, micelles, liquid crystals, colloidal suspensions, and polymers. They have a major impact on a broad spectrum of technological industries such as displays, plastics, soap and detergents, chemicals and petroleum, and pharmaceuticals.

  5. [Pressure support ventilation and proportional assist ventilation during weaning from mechanical ventilation].

    PubMed

    Aguirre-Bermeo, H; Bottiroli, M; Italiano, S; Roche-Campo, F; Santos, J A; Alonso, M; Mancebo, J

    2014-01-01

    To compare tolerance, duration of mechanical ventilation (MV) and clinical outcomes during weaning from MV in patients subjected to either pressure support ventilation (PSV) or proportional assist ventilation (PAV). A prospective, observational study was carried out. Intensive Care Unit. A total of 40 consecutive subjects were allocated to either the PSV or the PAV group until each group contained 20 patients. Patients were included in the study when they met the criteria to begin weaning and the attending physician decided to initiate the weaning process. The physician selected the modality and set the ventilatory parameters. None. Demographic data, respiratory mechanics, ventilatory parameters, duration of MV, and clinical outcomes (reintubation, tracheostomy, mortality). Baseline characteristics were similar in both groups. No significant differences were observed between the PSV and PAV groups in terms of the total duration of MV (10 [5-18] vs. 9 [7-19] days; P=.85), reintubation (5 [31%] vs. 3 [19%]; P=.69), or mortality (4 [20%] vs. 5 [25%] deaths; P=1). Eight patients (40%) in the PSV group and 6 patients (30%) in the PAV group (P=.74) required a return to volume assist-control ventilation due to clinical deterioration. Tolerance, duration of MV and clinical outcomes during weaning from mechanical ventilation were similar in PSV and PAV. Copyright © 2013 Elsevier España, S.L. and SEMICYUC. All rights reserved.

  6. Alterations of alveolar type II cells and intraalveolar surfactant after bronchoalveolar lavage and perfluorocarbon ventilation. An electron microscopical and stereological study in the rat lung

    PubMed Central

    Rüdiger, Mario; Wendt, Sebastian; Köthe, Lars; Burkhardt, Wolfram; Wauer, Roland R; Ochs, Matthias

    2007-01-01

    Background Repeated bronchoalveolar lavage (BAL) has been used in animals to induce surfactant depletion and to study therapeutical interventions of subsequent respiratory insufficiency. Intratracheal administration of surface active agents such as perfluorocarbons (PFC) can prevent the alveolar collapse in surfactant depleted lungs. However, it is not known how BAL or subsequent PFC administration affect the intracellular and intraalveolar surfactant pool. Methods Male wistar rats were surfactant depleted by BAL and treated for 1 hour by conventional mechanical ventilation (Lavaged-Gas, n = 5) or partial liquid ventilation with PF 5080 (Lavaged-PF5080, n = 5). For control, 10 healthy animals with gas (Healthy-Gas, n = 5) or PF5080 filled lungs (Healthy-PF5080, n = 5) were studied. A design-based stereological approach was used for quantification of lung parenchyma and the intracellular and intraalveolar surfactant pool at the light and electron microscopic level. Results Compared to Healthy-lungs, Lavaged-animals had more type II cells with lamellar bodies in the process of secretion and freshly secreted lamellar body-like surfactant forms in the alveoli. The fraction of alveolar epithelial surface area covered with surfactant and total intraalveolar surfactant content were significantly smaller in Lavaged-animals. Compared with Gas-filled lungs, both PF5080-groups had a significantly higher total lung volume, but no other differences. Conclusion After BAL-induced alveolar surfactant depletion the amount of intracellularly stored surfactant is about half as high as in healthy animals. In lavaged animals short time liquid ventilation with PF5080 did not alter intra- or extracellular surfactant content or subtype composition. PMID:17550584

  7. Human versus Computer Controlled Selection of Ventilator Settings: An Evaluation of Adaptive Support Ventilation and Mid-Frequency Ventilation.

    PubMed

    Mireles-Cabodevila, Eduardo; Diaz-Guzman, Enrique; Arroliga, Alejandro C; Chatburn, Robert L

    2012-01-01

    Background. There are modes of mechanical ventilation that can select ventilator settings with computer controlled algorithms (targeting schemes). Two examples are adaptive support ventilation (ASV) and mid-frequency ventilation (MFV). We studied how different clinician-chosen ventilator settings are from these computer algorithms under different scenarios. Methods. A survey of critical care clinicians provided reference ventilator settings for a 70 kg paralyzed patient in five clinical/physiological scenarios. The survey-derived values for minute ventilation and minute alveolar ventilation were used as goals for ASV and MFV, respectively. A lung simulator programmed with each scenario's respiratory system characteristics was ventilated using the clinician, ASV, and MFV settings. Results. Tidal volumes ranged from 6.1 to 8.3 mL/kg for the clinician, 6.7 to 11.9 mL/kg for ASV, and 3.5 to 9.9 mL/kg for MFV. Inspiratory pressures were lower for ASV and MFV. Clinician-selected tidal volumes were similar to the ASV settings for all scenarios except for asthma, in which the tidal volumes were larger for ASV and MFV. MFV delivered the same alveolar minute ventilation with higher end expiratory and lower end inspiratory volumes. Conclusions. There are differences and similarities among initial ventilator settings selected by humans and computers for various clinical scenarios. The ventilation outcomes are the result of the lung physiological characteristics and their interaction with the targeting scheme.

  8. Ventilation of CO2 from a reduced mantle and the climate history of Mars

    NASA Astrophysics Data System (ADS)

    Hirschmann, M. M.; Withers, A. C.

    2007-12-01

    A fundamental question regarding Martian history is the storage of carbon in the Martian interior and the processes and fluxes leading to ventilation of carbonaceous volatiles to the Martian crust and atmosphere. Evidence for liquid water on the Martian surface during the Late Noachian and Hesperian epochs (<3.7 Ga) likely requires a substantial accumulation of greenhouse gases in the Martian atmosphere. Most commonly, it is assumed that this gas was principally volcanogenic CO2. A key consideration regarding the extraction of C during partial melting of the Martian mantle is that the Martian mantle is thought to be reduced, with fO2 between IW and IW+1. Therefore, carbon likely resides chiefly as graphite, and extraction of CO2 from a graphite- saturated mantle can be estimated using thermodynamic models developed for terrestrial basalts by John Holloway. For melts derived from a graphite-saturated mantle at IW and IW+1, calculated liquids will have ~100 ppm and ~1000 ppm CO2, respectively, assuming basalt extraction at 1300 °C and 1 GPa. These concentrations do not change appreciably if temperature and pressure were both higher. Formation of the 50 km thick Martian crust at 4.5 Ga would therefore have liberated an atmosphere of 0.4-4 bars of CO2. Only the higher value is sufficient to maintain a strong greenhouse on early Mars, suggesting either that the Martian mantle must not be more reduced than IW+1 or that gases other than volcanogenic CO2 were responsible for the earliest Martian greenhouse atmosphere. It is sometimes suggested that degassing of CO2 associated with the gigantic (3 X 108 km3) Tharsis magmatic province was responsible for sustaining a significant Martian greenhouse later in Martian history (<3.7 Ga). However, at IW to IW+1, only 40-400 mbars CO2 could have been ventilated. Thus, if these calculations are applicable to the Martian mantle, either the greenhouse gases responsible for sustaining an equable climate compatible with liquid H2O on

  9. Intraoperative mechanical ventilation for the pediatric patient.

    PubMed

    Kneyber, Martin C J

    2015-09-01

    Invasive mechanical ventilation is required when children undergo general anesthesia for any procedure. It is remarkable that one of the most practiced interventions such as pediatric mechanical ventilation is hardly supported by any scientific evidence but rather based on personal experience and data from adults, especially as ventilation itself is increasingly recognized as a harmful intervention that causes ventilator-induced lung injury. The use of low tidal volume and higher levels of positive end-expiratory pressure became an integral part of lung-protective ventilation following the outcomes of clinical trials in critically ill adults. This approach has been readily adopted in pediatric ventilation. However, a clear association between tidal volume and mortality has not been ascertained in pediatrics. In fact, experimental studies have suggested that young children might be less susceptible to ventilator-induced lung injury. As such, no recommendations on optimal lung-protective ventilation strategy in children with or without lung injury can be made.

  10. The School Advanced Ventilation Engineering Software (SAVES)

    EPA Pesticide Factsheets

    The School Advanced Ventilation Engineering Software (SAVES) package is a tool to help school designers assess the potential financial payback and indoor humidity control benefits of Energy Recovery Ventilation (ERV) systems for school applications.

  11. The effect of changing ventilator settings on indices of ventilation inhomogeneity in small ventilated lungs

    PubMed Central

    Schmalisch, G; Proquitté, H; Roehr, CC; Wauer, RR

    2006-01-01

    Background In ventilated newborns the use of multiple breath washout (MBW) techniques for measuring both lung volume and ventilation inhomogeneity (VI) is hampered by the comparatively high dead space fraction. We studied how changes in ventilator settings affected VI indices in this particular population. Methods Using a computer simulation of a uniformly ventilated volume the interaction between VI indices (lung clearance index (LCI), moment ratios (M1/M0, M2/M0, AMDN1, AMDN2) of the washout curve) and tidal volume (VT), dead space (VD) and functional residual capacity (FRC) were calculated. The theoretical results were compared with measurements in 15 ventilated piglets (age <12 h, median weight 1135 g) by increasing the peak inspiratory pressure (PIP). FRC and VI indices were measured by MBW using 0.8% heptafluoropropane as tracer gas. Results The computer simulation showed that the sensitivity of most VI indices to changes in VD/VT and VT/FRC increase, in particular for VD/VT > 0.5. In piglets, the raised PIP caused a significant increase of VT from 15.4 ± 9.5 to 21.9 ± 14.7 (p = 0.003) and of the FRC from 31.6 ± 14.7 mL to 35.0 ± 15.9 mL (p = 0.006), whereas LCI (9.15 ± 0.75 to 8.55 ± 0.74, p = 0.019) and the moment ratios M1/M0, M2/M0 (p < 0.02) decreased significantly. No significant changes were seen in AMDN1 and AMDN2. The within-subject variability of the VI indices (coefficient of variation in brackets) was distinctly higher (LCI (9.8%), M1/M0 (6.6%), M2/M0 (14.6%), AMDN1 (9.1%), AMDN2 (16.3%)) compared to FRC measurements (5.6%). Computer simulations showed that significant changes in VI indices were exclusively caused by changes in VT and FRC and not by an improvement of the homogeneity of alveolar ventilation. Conclusion In small ventilated lungs with a high dead space fraction, indices of VI may be misinterpreted if the changes in ventilator settings are not considered. Computer simulations can help to prevent this misinterpretation. PMID

  12. Inadequate face mask ventilation--clinical applications.

    PubMed

    Goranović, Tatjana; Milić, Morena; Holjevac, Jadranka Katancić; Maldini, Branka; Sakić, Katarina

    2010-09-01

    Face mask ventilation is a life saving technique. This article will review aetiology and patophysiological consequences of inadequate mask ventilation. The main focus will be on circulatory changes during induction of anesthesia, before and in a short period after intubation that could be attributed to inadequate mask ventilation in humans.

  13. 30 CFR 57.8520 - Ventilation plan.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... system; (4) Locations of all main, booster and auxiliary fans not shown in paragraph (d) of this standard...) Significant changes in the ventilation system projected for one year. (c) Mine fan data for all active main... Underground Only § 57.8520 Ventilation plan. A plan of the mine ventilation system shall be set out by the...

  14. 14 CFR 27.831 - Ventilation.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction Personnel and Cargo Accommodations § 27.831 Ventilation. (a) The ventilating system for the pilot and passenger compartments must be designed to prevent... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Ventilation. 27.831 Section...

  15. 14 CFR 27.831 - Ventilation.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction Personnel and Cargo Accommodations § 27.831 Ventilation. (a) The ventilating system for the pilot and passenger compartments must be designed to prevent... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Ventilation. 27.831 Section...

  16. 14 CFR 27.831 - Ventilation.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction Personnel and Cargo Accommodations § 27.831 Ventilation. (a) The ventilating system for the pilot and passenger compartments must be designed to prevent... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Ventilation. 27.831 Section...

  17. 14 CFR 27.831 - Ventilation.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction Personnel and Cargo Accommodations § 27.831 Ventilation. (a) The ventilating system for the pilot and passenger compartments must be designed to prevent... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Ventilation. 27.831 Section...

  18. 46 CFR 194.15-5 - Ventilation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...) Ventilation of air conditioning systems serving the chemical laboratory shall be designed so that air cannot... 46 Shipping 7 2012-10-01 2012-10-01 false Ventilation. 194.15-5 Section 194.15-5 Shipping COAST....15-5 Ventilation. (a) Operations, reactions or experiments which produce toxic, noxious or...

  19. 14 CFR 27.831 - Ventilation.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction Personnel and Cargo Accommodations § 27.831 Ventilation. (a) The ventilating system for the pilot and passenger compartments must be designed to prevent... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Ventilation. 27.831 Section...

  20. 46 CFR 194.15-5 - Ventilation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...) Ventilation of air conditioning systems serving the chemical laboratory shall be designed so that air cannot... 46 Shipping 7 2011-10-01 2011-10-01 false Ventilation. 194.15-5 Section 194.15-5 Shipping COAST....15-5 Ventilation. (a) Operations, reactions or experiments which produce toxic, noxious or...

  1. 46 CFR 111.15-10 - Ventilation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... REQUIREMENTS Storage Batteries and Battery Chargers: Construction and Installation § 111.15-10 Ventilation. (a) General. Each room, locker, and box for storage batteries must be arranged or ventilated to prevent... with the battery charger so that the battery cannot be charged without ventilation. (c) Large battery...

  2. 46 CFR 116.610 - Ventilation ducts.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... type of piping, chamber, or conduit used for ventilation. (b) A ventilation duct, and materials incidental to its installation, must be made of noncombustible material. (c) Combustibles and other foreign materials are not allowed within ventilation ducts. However, metal piping and electrical wiring installed in...

  3. 46 CFR 111.15-10 - Ventilation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... REQUIREMENTS Storage Batteries and Battery Chargers: Construction and Installation § 111.15-10 Ventilation. (a) General. Each room, locker, and box for storage batteries must be arranged or ventilated to prevent... with the battery charger so that the battery cannot be charged without ventilation. (c) Large battery...

  4. 46 CFR 111.15-10 - Ventilation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... REQUIREMENTS Storage Batteries and Battery Chargers: Construction and Installation § 111.15-10 Ventilation. (a) General. Each room, locker, and box for storage batteries must be arranged or ventilated to prevent... with the battery charger so that the battery cannot be charged without ventilation. (c) Large battery...

  5. 46 CFR 111.15-10 - Ventilation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... REQUIREMENTS Storage Batteries and Battery Chargers: Construction and Installation § 111.15-10 Ventilation. (a) General. Each room, locker, and box for storage batteries must be arranged or ventilated to prevent... with the battery charger so that the battery cannot be charged without ventilation. (c) Large battery...

  6. 46 CFR 111.15-10 - Ventilation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... REQUIREMENTS Storage Batteries and Battery Chargers: Construction and Installation § 111.15-10 Ventilation. (a) General. Each room, locker, and box for storage batteries must be arranged or ventilated to prevent... with the battery charger so that the battery cannot be charged without ventilation. (c) Large battery...

  7. 14 CFR 125.117 - Ventilation.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Ventilation. 125.117 Section 125.117 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR CARRIERS....117 Ventilation. Each passenger or crew compartment must be suitably ventilated. Carbon...

  8. 14 CFR 125.117 - Ventilation.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 false Ventilation. 125.117 Section 125.117 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR CARRIERS....117 Ventilation. Each passenger or crew compartment must be suitably ventilated. Carbon...

  9. 9 CFR 91.21 - Ventilation.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 9 Animals and Animal Products 1 2014-01-01 2014-01-01 false Ventilation. 91.21 Section 91.21... LIVESTOCK FOR EXPORTATION Inspection of Vessels and Accommodations § 91.21 Ventilation. Each underdeck... mechanical ventilation that will furnish a complete change of air in each compartment every 2 minutes...

  10. 14 CFR 125.117 - Ventilation.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 3 2014-01-01 2014-01-01 false Ventilation. 125.117 Section 125.117 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR CARRIERS....117 Ventilation. Each passenger or crew compartment must be suitably ventilated. Carbon...

  11. 14 CFR 125.117 - Ventilation.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 false Ventilation. 125.117 Section 125.117 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR CARRIERS....117 Ventilation. Each passenger or crew compartment must be suitably ventilated. Carbon...

  12. 33 CFR 175.201 - Ventilation.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Ventilation. 175.201 Section 175.201 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) BOATING SAFETY EQUIPMENT REQUIREMENTS Ventilation § 175.201 Ventilation. No person may operate a boat built...

  13. 14 CFR 125.117 - Ventilation.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Ventilation. 125.117 Section 125.117 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR CARRIERS....117 Ventilation. Each passenger or crew compartment must be suitably ventilated. Carbon...

  14. 33 CFR 175.201 - Ventilation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Ventilation. 175.201 Section 175... SAFETY EQUIPMENT REQUIREMENTS Ventilation § 175.201 Ventilation. No person may operate a boat built after July 31, 1980, that has a gasoline engine for electrical generation, mechanical power, or...

  15. 46 CFR 153.312 - Ventilation system standards.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... ventilation system must be sized to change the air in the ventilated space at least 30 times per hour. (f) A... Handling Space Ventilation § 153.312 Ventilation system standards. A cargo handling space ventilation... (approx. 32.8 ft) from openings into or ventilation intakes for, accommodation or service spaces. (b) A...

  16. Fire Service Training. Ventilation. (Revised).

    ERIC Educational Resources Information Center

    North Carolina State Dept. of Community Colleges, Raleigh.

    One of a set of fourteen outlines for use in a course to train novice firemen, this guide covers ventilation practices and principles. As background, subjects such as heat transmission and building construction are included. The three objectives of this part of the course are to enable the fireman to (1) rescue trapped victims, (2) locate fires as…

  17. Preventing Ventilation On Sailboard Skegs

    NASA Technical Reports Server (NTRS)

    Caldwell, Richard A.

    1990-01-01

    Design effort undertaken to solve spinout problem plaguing high-performance sailboards. Proposed skeg section designed by use of computer model of pressure field and boundary layer. Prevents ventilation by maintaining attached boundary-layer flow throughout operating environment. Cavitation also avoided by preventing valleys in pressure distribution while skeg operated throughout its range.

  18. Preventing Ventilation On Sailboard Skegs

    NASA Technical Reports Server (NTRS)

    Caldwell, Richard A.

    1990-01-01

    Design effort undertaken to solve spinout problem plaguing high-performance sailboards. Proposed skeg section designed by use of computer model of pressure field and boundary layer. Prevents ventilation by maintaining attached boundary-layer flow throughout operating environment. Cavitation also avoided by preventing valleys in pressure distribution while skeg operated throughout its range.

  19. Prognosis of mechanically ventilated patients.

    PubMed Central

    Papadakis, M A; Lee, K K; Browner, W S; Kent, D L; Matchar, D B; Kagawa, M K; Hallenbeck, J; Lee, D; Onishi, R; Charles, G

    1993-01-01

    In this Department of Veterans Affairs cooperative study, we examined predictors of in-hospital and 1-year mortality of 612 mechanically ventilated patients from 6 medical intensive care units in a retrospective cohort design. The outcome variable was vital status at hospital discharge and after 1 year. The results showed that 97% of patients were men, the mean age was 63 +/- 11 years (SD), and hospital mortality was 64% (95% confidence interval, 60% to 68%). Within the next year, an additional 38% of hospital survivors died, for a total 1-year mortality of 77% (95% confidence interval, 73% to 80%). Hospital and 1-year mortality, respectively, for patients older than 70 years was 76% and 94%, for those with serum albumin levels below 20 grams per liter it was 92% and 96%, for those with an Acute Physiology and Chronic Health Evaluation II (APACHE II) score greater than 35 it was 91% and 98%, and for patients who were being mechanically ventilated after cardiopulmonary resuscitation it was 86% and 90%. The mortality ratio (actual mortality versus APACHE II-predicted mortality) was 1.15. Conclusions are that patient age, APACHE II score, serum albumin levels, or the use of cardiopulmonary resuscitation may identify a subset of mechanically ventilated veterans for whom mechanical ventilation provides little or no benefit. PMID:8128673

  20. Control of ventilation in elite synchronized swimmers.

    PubMed

    Bjurström, R L; Schoene, R B

    1987-09-01

    Synchronized swimmers perform strenuous underwater exercise during prolonged breath holds. To investigate the role of the control of ventilation and lung volumes in these athletes, we studied the 10 members of the National Synchronized Swim Team including an olympic gold medalist and 10 age-matched controls. We evaluated static pulmonary function, hypoxic and hypercapnic ventilatory drives, and normoxic and hyperoxic breath holding. Synchronized swimmers had an increased total lung capacity and vital capacity compared with controls (P less than 0.005). The hypoxic ventilatory response (expressed as the hyperbolic shape parameter A) was lower in the synchronized swimmers than controls with a mean value of 29.2 +/- 2.6 (SE) and 65.6 +/- 7.1, respectively (P less than 0.001). The hypercapnic ventilatory response [expressed as S, minute ventilation (1/min)/alveolar CO2 partial pressure (Torr)] was no different between synchronized swimmers and controls. Breath-hold duration during normoxia was greater in the synchronized swimmers, with a mean value of 108.6 +/- 4.8 (SE) vs. 68.03 +/- 8.1 s in the controls (P less than 0.001). No difference was seen in hyperoxic breath-hold times between groups. During breath holding synchronized swimmers demonstrated marked apneic bradycardia expressed as either absolute or heart rate change from basal heart rate as opposed to the controls, in whom heart rate increased during breath holds. Therefore the results show that elite synchronized swimmers have increased lung volumes, blunted hypoxic ventilatory responses, and a marked apneic bradycardia that may provide physiological characteristics that offer a competitive advantage for championship performance.(ABSTRACT TRUNCATED AT 250 WORDS)

  1. Fire protection countermeasures for containment ventilation systems

    SciTech Connect

    Alvares, N.; Beason, D.; Bergman, V.; Creighton, J.; Ford, H.; Lipska, A.

    1980-08-25

    The goal of this project is to find countermeasures to protect High Efficiency Particulate Air (HEPA) filters, in exit ventilation ducts, from the heat and smoke generated by fire. Initially, methods were developed to cool fire-heated air by fine water spray upstream of the filters. It was recognized that smoke aerosol exposure to HEPA filters could also cause disruption of the containment system. Through testing and analysis, several methods to partially mitigate the smoke exposure to the HEPA filters were identified. A continuous, movable, high-efficiency prefilter using modified commercial equipment was designed. The technique is capable of protecting HEPA filters over the total time duration of the test fires. The reason for success involved the modification of the prefiltration media. Commercially available filter media has particle sorption efficiency that is inversely proportional to media strength. To achieve properties of both efficiency and strength, rolling filter media were laminated with the desired properties. The approach was Edisonian, but truncation in short order to a combination of prefilters was effective. The application of this technique was qualified, since it is of use only to protect HEPA filters from fire-generated smoke aerosols. It is not believed that this technique is cost effective in the total spectrum of containment systems, especially if standard fire protection systems are available in the space. But in areas of high-fire risk, where the potential fuel load is large and ignition sources are plentiful, the complication of a rolling prefilter in exit ventilation ducts to protect HEPA filters from smoke aerosols is definitely justified.

  2. Fire protection countermeasures for containment ventilation systems

    SciTech Connect

    Alvares, N.J.; Beason, D.G.; Bergman, W.; Ford, H.W.; Lipska, A.E.

    1980-01-01

    The goal of this project is to find countermeasures to protect HEPA filters in exit ventilation ducts from the heat and smoke generated by fire. Several methods for partially mitigating the smoke exposure to the HEPA filters were identified through testing and analysis. These independently involve controlling the fuel, controlling the fire, and intercepting the smoke aerosol prior to its sorption on the HEPA filter. Exit duct treatment of aerosols is not unusual in industrial applications and involves the use of scrubbers, prefilters, and inertial impaction, depending on the size, distribution, and concentration of the subject aerosol. However, when these unmodified techniques were applied to smoke aerosols from fires on materials, common to experimental laboratories of LLNL, it was found they offered minimal protection to the HEPA filters. Ultimately, a continuous, movable, high-efficiency prefilter using modified commercial equipment was designed. This technique is capable of protecting HEPA filters over the total duration of the test fires. The reason for success involved the modificaton of the prefiltration media. Commercially available filter media has a particle sorption efficiency that is inversely proportional to media strength. To achieve properties of both efficiency and strength, we laminated rolling filter media with the desired properties. It is not true that the use of rolling prefilters solely to protect HEPA filters from fire-generated smoke aerosols is cost effective in every type of containment system, especially if standard fire-protection systems are available in the space. But in areas of high fire risk, where the potential fuel load is large and ignition sources are plentiful, the complication of a rolling prefilter in exit ventilation ducts to protect HEPA filters from smoke aerosols is definitely justified.

  3. Ventilation heterogeneity is a major determinant of airway hyperresponsiveness in asthma, independent of airway inflammation

    PubMed Central

    Downie, Sue R; Salome, Cheryl M; Verbanck, Sylvia; Thompson, Bruce; Berend, Norbert; King, Gregory G

    2007-01-01

    Background Airway hyperresponsiveness is the ability of airways to narrow excessively in response to inhaled stimuli and is a key feature of asthma. Airway inflammation and ventilation heterogeneity have been separately shown to be associated with airway hyperresponsiveness. A study was undertaken to establish whether ventilation heterogeneity is associated with airway hyperresponsiveness independently of airway inflammation in subjects with asthma and to determine the effect of inhaled corticosteroids on this relationship. Methods Airway inflammation was measured in 40 subjects with asthma by exhaled nitric oxide, ventilation heterogeneity by multiple breath nitrogen washout and airway hyperresponsiveness by methacholine challenge. In 18 of these subjects with uncontrolled symptoms, measurements were repeated after 3 months of treatment with inhaled beclomethasone dipropionate. Results At baseline, airway hyperresponsiveness was independently predicted by airway inflammation (partial r2 = 0.20, p<0.001) and ventilation heterogeneity (partial r2 = 0.39, p<0.001). Inhaled corticosteroid treatment decreased airway inflammation (p = 0.002), ventilation heterogeneity (p = 0.009) and airway hyperresponsiveness (p<0.001). After treatment, ventilation heterogeneity was the sole predictor of airway hyperresponsiveness (r2 = 0.64, p<0.001). Conclusions Baseline ventilation heterogeneity is a strong predictor of airway hyperresponsiveness, independent of airway inflammation in subjects with asthma. Its persistent relationship with airway hyperresponsiveness following anti‐inflammatory treatment suggests that it is an important independent determinant of airway hyperresponsiveness. Normalisation of ventilation heterogeneity is therefore a potential goal of treatment that may lead to improved long‐term outcomes. PMID:17311839

  4. Cardiovascular effects of mechanical ventilation and weaning.

    PubMed

    Frazier, Susan K

    2008-03-01

    Because of their anatomic position in the closed thoracic cavity, the heart and lungs interact during each ventilation cycle. The application of mechanical ventilation and subsequent removal changes normal ventilatory mechanics and produces alterations in cardiac preload and afterload that influence global hemodynamic state and delivery of oxygen and nutrients. Adverse cardiovascular responses to mechanical ventilation and weaning from ventilation include hemodynamic alterations and instability, myocardial ischemia, autonomic dysfunction, and cardiac dysrhythmias. Clinicians must have a clear understanding of the cardiovascular effects of mechanical ventilation and weaning so they may anticipate, recognize, and effectively manage negative effects and improve patient outcomes.

  5. Economics of mechanical ventilation and respiratory failure.

    PubMed

    Cooke, Colin R

    2012-01-01

    For patients with acute respiratory failure, mechanical ventilation provides the most definitive life-sustaining therapy. Because of the intense resources required to care for these patients, its use accounts for considerable costs. There is great societal need to ensure that use of mechanical ventilation maximizes societal benefits while minimizing costs, and that mechanical ventilation, and ventilator support in general, is delivered in the most efficient and cost-effective manner. This review summarizes the economic aspects of mechanical ventilation and summarizes the existing literature that examines its economic impact cost effectiveness.

  6. Patient-ventilator interaction: an overview.

    PubMed

    Prinianakis, George; Kondili, Eumorfia; Georgopoulos, Dimitris

    2005-06-01

    During assisted mechanical ventilation, the total pressure applied to respiratory system is the sum of ventilator and muscle pressure. As a result, the respiratory system is under the influence of two pumps, the ventilator pump (ie, Paw), which is controlled by the physician's brain and the capabilities of the ventilator, and the patient's own respiratory muscle pump (Pmus), which is controlled by the patient's brain. The patient-ventilator interaction is mainly an expression of the function of these two brains, which should be in harmony to promote patient-ventilator synchrony. The achievement of this harmony depends exclusively on the physician, who should be aware that during assisted mechanical ventilation the respiratory system is not a passive structure but reacts to pressure delivered by the ventilator via various feedback systems and, depending on several factors both to the ventilator and patient, may modify the function of the ventilator. Finally, the physician should know that the ventilator imposes significant constraints to the respiratory system, the magnitude of which depends heavily on the triggering variable, the variable that controls the gas delivery and the cycling off criterion.

  7. Night ventilation control strategies in office buildings

    SciTech Connect

    Wang, Zhaojun; Yi, Lingli; Gao, Fusheng

    2009-10-15

    In moderate climates night ventilation is an effective and energy-efficient approach to improve the indoor thermal environment for office buildings during the summer months, especially for heavyweight construction. However, is night ventilation a suitable strategy for office buildings with lightweight construction located in cold climates? In order to answer this question, the whole energy-consumption analysis software EnergyPlus was used to simulate the indoor thermal environment and energy consumption in typical office buildings with night mechanical ventilation in three cities in northern China. The summer outdoor climate data was analyzed, and three typical design days were chosen. The most important factors influencing night ventilation performance such as ventilation rates, ventilation duration, building mass and climatic conditions were evaluated. When night ventilation operation time is closer to active cooling time, the efficiency of night ventilation is higher. With night ventilation rate of 10 ach, the mean radiant temperature of the indoor surface decreased by up to 3.9 C. The longer the duration of operation, the more efficient the night ventilation strategy becomes. The control strategies for three locations are given in the paper. Based on the optimized strategies, the operation consumption and fees are calculated. The results show that more energy is saved in office buildings cooled by a night ventilation system in northern China than ones that do not employ this strategy. (author)

  8. Airway pressure release ventilation: theory and practice.

    PubMed

    Frawley, P M; Habashi, N M

    2001-05-01

    Airway pressure release ventilation (APRV) is a relatively new mode of ventilation, that only became commercially available in the United States in the mid-1990s. Airway pressure release ventilation produces tidal ventilation using a method that differs from any other mode. It uses a release of airway pressure from an elevated baseline to simulate expiration. The elevated baseline facilitates oxygenation, and the timed releases aid in carbon dioxide removal. Advantages of APRV include lower airway pressures, lower minute ventilation, minimal adverse effects on cardio-circulatory function, ability to spontaneously breathe throughout the entire ventilatory cycle, decreased sedation use, and near elimination of neuromuscular blockade. Airway pressure release ventilation is consistent with lung protection strategies that strive to limit lung injury associated with mechanical ventilation. Future research will probably support the use of APRV as the primary mode of choice for patients with acute lung injury.

  9. Evaluation of AY/AZ tank farm ventilation system during aging waste retrieval operations

    SciTech Connect

    Wong, J.J.; Waters, E.D.

    1995-01-01

    Waste Management is currently planning to demonstrate mobilization of radioactive waste sludges in Tank 101-AZ beginning in October 1991. The retrieval system being designed will utilize mixer pumps that generate high-velocity, high-volume submerged liquid jets to mobilize settled solids. There is concern that these jets may also generate radioactive aerosols, some of which may be carried into the tank Ventilation system. The purpose of this study is to determine if the current AY/AZ ventilation system or the proposed ventilation system upgrade (Project W-030) will provide adequate deentrainment of liquid and solid aerosols during mixer pump operations, or if the radioactive aerosols will overload the HEPA filters.

  10. Iloprost drug delivery during infant conventional and high-frequency oscillatory ventilation

    PubMed Central

    DiBlasi, Robert M.; Crotwell, Dave N.; Shen, Shuijie; Zheng, Jiang; Fink, James B.; Yung, Delphine

    2016-01-01

    Abstract Iloprost is a selective pulmonary vasodilator approved for inhalation by the Food and Drug Administration. Iloprost has been increasingly used in the management of critically ill neonates with hypoxic lung disease. This in vitro study was designed to test the hypothesis that aerosol drug delivery could be effectively administered to infants with both conventional ventilation and high-frequency oscillatory ventilation (HFOV). A neonatal test lung model configured with newborn lung mechanics was ventilated with a conventional ventilator and an HFOV with standard settings. A vibrating-mesh nebulizer was placed (1) proximal to the patient airway in the inspiratory limb between the humidifier probe and patient wye (conventional) as well as between the vent circuit and the endotracheal tube (ETT) for HFOV and (2) between the ventilator and humidifier (distal). Iloprost was nebulized in three separate runs using three new nebulizers in each of the circuit locations. A collecting filter was placed at the distal end of the ETT for each trial. Iloprost was quantified using high-performance liquid chromatography. The percentage of nominal dose delivered was greater with the nebulizer placed proximal to the airway for conventional ventilation (10.74% ± 2%) and HFOV (29% ± 2%) than with it placed in the distal position (2.96% ± 0.2% vs. 0.96% ± 0.8%, respectively; P < 0.05). Drug delivery in proximal position was nearly threefold greater during HFOV than during conventional ventilation. In conclusion, iloprost drug delivery was best achieved when the nebulizer was placed proximal to the patient airway during neonatal mechanical ventilation. Drug delivery appears to be more efficient during HFOV than during conventional ventilation. PMID:27162615

  11. Summary of human responses to ventilation

    SciTech Connect

    Seppanen, Olli A.; Fisk, William J.

    2004-06-01

    The effects of ventilation on indoor air quality and health is a complex issue. It is known that ventilation is necessary to remove indoor generated pollutants from indoor air or dilute their concentration to acceptable levels. But, as the limit values of all pollutants are not known, the exact determination of required ventilation rates based on pollutant concentrations and associated risks is seldom possible. The selection of ventilation rates has to be based also on epidemiological research (e.g. Seppanen et al., 1999), laboratory and field experiments (e.g. CEN 1996, Wargocki et al., 2002a) and experience (e.g. ECA 2003). Ventilation may also have harmful effects on indoor air quality and climate if not properly designed, installed, maintained and operated as summarized by Seppdnen (2003). Ventilation may bring indoors harmful substances that deteriorate the indoor environment. Ventilation also affects air and moisture flow through the building envelope and may lead to moisture problems that deteriorate the structures of the building. Ventilation changes the pressure differences over the structures of building and may cause or prevent the infiltration of pollutants from structures or adjacent spaces. Ventilation is also in many cases used to control the thermal environment or humidity in buildings. Ventilation can be implemented with various methods which may also affect health (e.g. Seppdnen and Fisk, 2002, Wargocki et al., 2002a). In non residential buildings and hot climates, ventilation is often integrated with air-conditioning which makes the operation of ventilation system more complex. As ventilation is used for many purposes its health effects are also various and complex. This paper summarizes the current knowledge on positive and negative effects of ventilation on health and other human responses. The focus of the paper is on office-type working environment and residential buildings. In the industrial premises the problems of air quality are usually

  12. Stockpiling Ventilators for Influenza Pandemics

    PubMed Central

    Araz, Ozgur M.; Morton, David P.; Johnson, Gregory P.; Damien, Paul; Clements, Bruce; Meyers, Lauren Ancel

    2017-01-01

    In preparing for influenza pandemics, public health agencies stockpile critical medical resources. Determining appropriate quantities and locations for such resources can be challenging, given the considerable uncertainty in the timing and severity of future pandemics. We introduce a method for optimizing stockpiles of mechanical ventilators, which are critical for treating hospitalized influenza patients in respiratory failure. As a case study, we consider the US state of Texas during mild, moderate, and severe pandemics. Optimal allocations prioritize local over central storage, even though the latter can be deployed adaptively, on the basis of real-time needs. This prioritization stems from high geographic correlations and the slightly lower treatment success assumed for centrally stockpiled ventilators. We developed our model and analysis in collaboration with academic researchers and a state public health agency and incorporated it into a Web-based decision-support tool for pandemic preparedness and response. PMID:28518041

  13. Experimental research on the indoor temperature and humidity fields in radiant ceiling air-conditioning system under natural ventilation

    NASA Astrophysics Data System (ADS)

    Huang, Tao; Xiang, Yutong; Wang, Yonghong

    2017-05-01

    In this paper, the indoor temperature and humidity fields of the air in a metal ceiling radiant panel air conditioning system with fresh air under natural ventilation were researched. The temperature and humidity distributions at different height and different position were compared. Through the computation analysis of partial pressure of water vapor, the self-recovery characteristics of humidity after the natural ventilation was discussed.

  14. [Mechanical ventilation during thoracic anesthesia].

    PubMed

    Valenza, F

    1999-05-01

    Aim of the study was to test individual mechanical and functional responses to open chest lateral decubitus during one lung ventilation. We measured dependent lung pressure volume (P-V) curves of 19 patients during supine and lateral decubitus. We found that patients characterized by high FEV1 developed greater changes in P-V curve shape than those characterized by low FEV1. Based on these results we decided to test a ventilation strategy characterized by the use of ZEEP or PEEP = 10 cm H2O applied to the dependent lung. In a preliminary set of patients stratified by FEV1 we found that PEEP deteriorated PaO2/FiO2 in patients with low FEV1, while there was a trend towards improvement in patients with high FEV1. It is possible that dependent lung PEEP counteracts atelectasias in normal lungs, while it may divert blood flow or create dead space in patients with sick and stiff lungs. We conclude that during one lung ventilation in open chest lateral decubitus, ventilatory setting need to be individually tailored.

  15. 46 CFR 153.545 - Special requirements for liquid sulfur.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Special requirements for liquid sulfur. 153.545 Section... Equipment Special Requirements § 153.545 Special requirements for liquid sulfur. (a) A containment system carrying liquid sulfur must have: (1) A cargo tank ventilation system that: (i) Maintains the H2S...

  16. 46 CFR 153.545 - Special requirements for liquid sulfur.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Special requirements for liquid sulfur. 153.545 Section... Equipment Special Requirements § 153.545 Special requirements for liquid sulfur. (a) A containment system carrying liquid sulfur must have: (1) A cargo tank ventilation system that: (i) Maintains the H2S...

  17. 46 CFR 153.545 - Special requirements for liquid sulfur.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Special requirements for liquid sulfur. 153.545 Section... Equipment Special Requirements § 153.545 Special requirements for liquid sulfur. (a) A containment system carrying liquid sulfur must have: (1) A cargo tank ventilation system that: (i) Maintains the H2S...

  18. 46 CFR 153.545 - Special requirements for liquid sulfur.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Special requirements for liquid sulfur. 153.545 Section... Equipment Special Requirements § 153.545 Special requirements for liquid sulfur. (a) A containment system carrying liquid sulfur must have: (1) A cargo tank ventilation system that: (i) Maintains the H2S...

  19. 46 CFR 153.545 - Special requirements for liquid sulfur.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Special requirements for liquid sulfur. 153.545 Section... Equipment Special Requirements § 153.545 Special requirements for liquid sulfur. (a) A containment system carrying liquid sulfur must have: (1) A cargo tank ventilation system that: (i) Maintains the H2S...

  20. Development of a Residential Integrated Ventilation Controller

    SciTech Connect

    Staff Scientist; Walker, Iain; Sherman, Max; Dickerhoff, Darryl

    2011-12-01

    The goal of this study was to develop a Residential Integrated Ventilation Controller (RIVEC) to reduce the energy impact of required mechanical ventilation by 20percent, maintain or improve indoor air quality and provide demand response benefits. This represents potential energy savings of about 140 GWh of electricity and 83 million therms of natural gas as well as proportional peak savings in California. The RIVEC controller is intended to meet the 2008 Title 24 requirements for residential ventilation as well as taking into account the issues of outdoor conditions, other ventilation devices (including economizers), peak demand concerns and occupant preferences. The controller is designed to manage all the residential ventilation systems that are currently available. A key innovation in this controller is the ability to implement the concept of efficacy and intermittent ventilation which allows time shifting of ventilation. Using this approach ventilation can be shifted away from times of high cost or high outdoor pollution towards times when it is cheaper and more effective. Simulations, based on the ones used to develop the new residential ventilation requirements for the California Buildings Energy code, were used to further define the specific criteria and strategies needed for the controller. These simulations provide estimates of the energy, peak power and contaminant improvement possible for different California climates for the various ventilation systems. Results from a field test of the prototype controller corroborate the predicted performance.

  1. Prevention of ventilator-associated pneumonia.

    PubMed

    Lau, Arthur C W; So, H M; Tang, S L; Yeung, Alwin; Lam, S M; Yan, W W

    2015-02-01

    Ventilator-associated pneumonia is the commonest, yet mostly preventable, infection in mechanically ventilated patients. Successful control of ventilator-associated pneumonia can save hospitalisation cost, and is possible by using a multidisciplinary clinical and administrative approach. The ventilator-associated pneumonia rate should be expressed as the number of ventilator-associated pneumonia days per 1000 ventilator days to take into account the device-utilisation duration for meaningful comparison. Various strategies address the issue, including general infection control measures, body positioning, intubation and mechanical ventilation, oral and gastro-intestinal tract, endotracheal tube, airway pressure, cuff pressure, selective digestive and/or oropharyngeal decontamination, and probiotic or early antibiotic treatment, as well as overall administration at a policy level. The rationale and controversy of these approaches are discussed in this article. The authors suggest that all units treating mechanically ventilated patients should have a ventilator-associated pneumonia prevention protocol in place, and ventilator-associated pneumonia should be seriously considered as a key performance indicator in local intensive care units.

  2. Temperature of gas delivered from ventilators.

    PubMed

    Chikata, Yusuke; Onodera, Mutsuo; Imanaka, Hideaki; Nishimura, Masaji

    2013-01-01

    Although heated humidifiers (HHs) are the most efficient humidifying device for mechanical ventilation, some HHs do not provide sufficient humidification when the inlet temperature to the water chamber is high. Because portable and home-care ventilators use turbines, blowers, pistons, or compressors to inhale in ambient air, they may have higher gas temperature than ventilators with piping systems. We carried out a bench study to investigate the temperature of gas delivered from portable and home-care ventilators, including the effects of distance from ventilator outlet, fraction of inspiratory oxygen (FIO2), and minute volume (MV). We evaluated five ventilators equipped with turbine, blower, piston, or compressor system. Ambient air temperature was adjusted to 24°C ± 0.5°C, and ventilation was set at FIO2 0.21, 0.6, and 1.0, at MV 5 and 10 L/min. We analyzed gas temperature at 0, 40, 80, and 120 cm from ventilator outlet and altered ventilator settings. While temperature varied according to ventilators, the outlet gas temperature of ventilators became stable after, at the most, 5 h. Gas temperature was 34.3°C ± 3.9°C at the ventilator outlet, 29.5°C ± 2.2°C after 40 cm, 25.4°C ± 1.2°C after 80 cm and 25.1°C ± 1.2°C after 120 cm (P < 0.01). FIO2 and MV did not affect gas temperature. Gas delivered from portable and home-care ventilator was not too hot to induce heated humidifier malfunctioning. Gas soon declined when passing through the limb.

  3. Wettability of partially suspended graphene

    SciTech Connect

    Ondarçuhu, Thierry; Thomas, Vincent; Nuñez, Marc; Dujardin, Erik; Rahman, Atikur; Black, Charles T.; Checco, Antonio

    2016-04-13

    Dependence on the wettability of graphene on the nature of the underlying substrate remains only partially understood. We systematically investigate the role of liquid-substrate interactions on the wettability of graphene by varying the area fraction of suspended graphene from 0 to 95% by means of nanotextured substrates. We find that completely suspended graphene exhibits the highest water contact angle (85° ± 5°) compared to partially suspended or supported graphene, regardless of the hydrophobicity (hydrophilicity) of the substrate. Moreover, 80% of the long-range water-substrate interactions are screened by the graphene monolayer, the wettability of which is primarily determined by short-range graphene-liquid interactions. By its well-defined chemical and geometrical properties, supported graphene therefore provides a model system to elucidate the relative contribution of short and long range interactions to the macroscopic contact angle.

  4. Wettability of partially suspended graphene

    PubMed Central

    Ondarçuhu, Thierry; Thomas, Vincent; Nuñez, Marc; Dujardin, Erik; Rahman, Atikur; Black, Charles T.; Checco, Antonio

    2016-01-01

    The dependence of the wettability of graphene on the nature of the underlying substrate remains only partially understood. Here, we systematically investigate the role of liquid-substrate interactions on the wettability of graphene by varying the area fraction of suspended graphene from 0 to 95% by means of nanotextured substrates. We find that completely suspended graphene exhibits the highest water contact angle (85° ± 5°) compared to partially suspended or supported graphene, regardless of the hydrophobicity (hydrophilicity) of the substrate. Further, 80% of the long-range water-substrate interactions are screened by the graphene monolayer, the wettability of which is primarily determined by short-range graphene-liquid interactions. By its well-defined chemical and geometrical properties, supported graphene therefore provides a model system to elucidate the relative contribution of short and long range interactions to the macroscopic contact angle. PMID:27072195

  5. Particle deposition in ventilation ducts

    SciTech Connect

    Sippola, Mark Raymond

    2002-09-01

    Exposure to airborne particles is detrimental to human health and indoor exposures dominate total exposures for most people. The accidental or intentional release of aerosolized chemical and biological agents within or near a building can lead to exposures of building occupants to hazardous agents and costly building remediation. Particle deposition in heating, ventilation and air-conditioning (HVAC) systems may significantly influence exposures to particles indoors, diminish HVAC performance and lead to secondary pollutant release within buildings. This dissertation advances the understanding of particle behavior in HVAC systems and the fates of indoor particles by means of experiments and modeling. Laboratory experiments were conducted to quantify particle deposition rates in horizontal ventilation ducts using real HVAC materials. Particle deposition experiments were conducted in steel and internally insulated ducts at air speeds typically found in ventilation ducts, 2-9 m/s. Behaviors of monodisperse particles with diameters in the size range 1-16 μm were investigated. Deposition rates were measured in straight ducts with a fully developed turbulent flow profile, straight ducts with a developing turbulent flow profile, in duct bends and at S-connector pieces located at duct junctions. In straight ducts with fully developed turbulence, experiments showed deposition rates to be highest at duct floors, intermediate at duct walls, and lowest at duct ceilings. Deposition rates to a given surface increased with an increase in particle size or air speed. Deposition was much higher in internally insulated ducts than in uninsulated steel ducts. In most cases, deposition in straight ducts with developing turbulence, in duct bends and at S-connectors at duct junctions was higher than in straight ducts with fully developed turbulence. Measured deposition rates were generally higher than predicted by published models. A model incorporating empirical equations based on the

  6. Harvesting contaminants from liquid

    DOEpatents

    Simpson, John T.; Hunter, Scott R.

    2016-05-31

    Disclosed are examples of apparatuses for evaporative purification of a contaminated liquid. In each example, there is a vessel for storing the contaminated fluid. The vessel includes a surface coated with a layer of superhydrophobic material and the surface is at least partially in contact with the contaminated liquid. The contaminants do not adhere to the surface as the purified liquid evaporates, thus allowing the contaminants to be harvested.

  7. Is Titan Partially Differentiated?

    NASA Astrophysics Data System (ADS)

    Mitri, G.; Pappalardo, R. T.; Stevenson, D. J.

    2009-12-01

    The recent measurement of the gravity coefficients from the Radio Doppler data of the Cassini spacecraft has improved our knowledge of the interior structure of Titan (Rappaport et al. 2008 AGU, P21A-1343). The measured gravity field of Titan is dominated by near hydrostatic quadrupole components. We have used the measured gravitational coefficients, thermal models and the hydrostatic equilibrium theory to derive Titan's interior structure. The axial moment of inertia gives us an indication of the degree of the interior differentiation. The inferred axial moment of inertia, calculated using the quadrupole gravitational coefficients and the Radau-Darwin approximation, indicates that Titan is partially differentiated. If Titan is partially differentiated then the interior must avoid melting of the ice during its evolution. This suggests a relatively late formation of Titan to avoid the presence of short-lived radioisotopes (Al-26). This also suggests the onset of convection after accretion to efficiently remove the heat from the interior. The outer layer is likely composed mainly of water in solid phase. Thermal modeling indicates that water could be present also in liquid phase forming a subsurface ocean between an outer ice I shell and a high pressure ice layer. Acknowledgments: This work was conducted at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.

  8. Partially solidified systems

    NASA Astrophysics Data System (ADS)

    The evolution of magmas is a topic of considerable importance in geology and geophysics because it affects volcanology, igneous petrology, geothermal energy sources, mantle convection, and the thermaland chemical evolution of the earth. The dynamics and evolution of magmas are strongly affected by the presence of solid crystals that occur either in suspension in liquid or as a rigid porous matrix through which liquid magma can percolate. Such systems are physically complex and difficult to model mathematically. Similar physical situations are encountered by metallurgists who study the solidification of molten alloys, and applied mathematicians have long been interested in such moving boundary problems. Clearly, it would be of mutual benefit to bring together scientists, engineers, and mathematicians with a common interest in such systems. Such a meeting is being organized as a North Atlantic Treaty Organization (NATO) Advanced Research Workshop on the Structure and Dynamics of Partially Solidified Systems, to be held at Stanford University's Fallen Leaf Lodge at Tahoe, Calif., May 12-16, 1986 The invited speakers and their topics are

  9. A comparison of synchronized intermittent mandatory ventilation and pressure-regulated volume control ventilation in elderly patients with acute exacerbations of COPD and respiratory failure

    PubMed Central

    Chang, Suchi; Shi, Jindong; Fu, Cuiping; Wu, Xu; Li, Shanqun

    2016-01-01

    Background COPD is the third leading cause of death worldwide. Acute exacerbations of COPD may cause respiratory failure, requiring intensive care unit admission and mechanical ventilation. Intensive care unit patients with acute exacerbations of COPD requiring mechanical ventilation have higher mortality rates than other hospitalized patients. Although mechanical ventilation is the most effective intervention for these conditions, invasive ventilation techniques have yielded variable effects. Objective We evaluated pressure-regulated volume control (PRVC) ventilation treatment efficacy and preventive effects on pulmonary barotrauma in elderly COPD patients with respiratory failure. Patients and methods Thirty-nine intubated patients were divided into experimental and control groups and treated with the PRVC and synchronized intermittent mandatory ventilation – volume control methods, respectively. Vital signs, respiratory mechanics, and arterial blood gas analyses were monitored for 2–4 hours and 48 hours. Results Both groups showed rapidly improved pH, partial pressure of oxygen (PaO2), and PaO2 per fraction of inspired O2 levels and lower partial pressure of carbon dioxide (PaCO2) levels. The pH and PaCO2 levels at 2–4 hours were lower and higher, respectively, in the test group than those in the control group (P<0.05 for both); after 48 hours, blood gas analyses showed no statistical difference in any marker (P>0.05). Vital signs during 2–4 hours and 48 hours of treatment showed no statistical difference in either group (P>0.05). The level of peak inspiratory pressure in the experimental group after mechanical ventilation for 2–4 hours and 48 hours was significantly lower than that in the control group (P<0.05), while other variables were not significantly different between groups (P>0.05). Conclusion Among elderly COPD patients with respiratory failure, application of PRVC resulted in rapid improvement in arterial blood gas analyses while maintaining

  10. A comparison of synchronized intermittent mandatory ventilation and pressure-regulated volume control ventilation in elderly patients with acute exacerbations of COPD and respiratory failure.

    PubMed

    Chang, Suchi; Shi, Jindong; Fu, Cuiping; Wu, Xu; Li, Shanqun

    2016-01-01

    COPD is the third leading cause of death worldwide. Acute exacerbations of COPD may cause respiratory failure, requiring intensive care unit admission and mechanical ventilation. Intensive care unit patients with acute exacerbations of COPD requiring mechanical ventilation have higher mortality rates than other hospitalized patients. Although mechanical ventilation is the most effective intervention for these conditions, invasive ventilation techniques have yielded variable effects. We evaluated pressure-regulated volume control (PRVC) ventilation treatment efficacy and preventive effects on pulmonary barotrauma in elderly COPD patients with respiratory failure. Thirty-nine intubated patients were divided into experimental and control groups and treated with the PRVC and synchronized intermittent mandatory ventilation - volume control methods, respectively. Vital signs, respiratory mechanics, and arterial blood gas analyses were monitored for 2-4 hours and 48 hours. Both groups showed rapidly improved pH, partial pressure of oxygen (PaO2), and PaO2 per fraction of inspired O2 levels and lower partial pressure of carbon dioxide (PaCO2) levels. The pH and PaCO2 levels at 2-4 hours were lower and higher, respectively, in the test group than those in the control group (P<0.05 for both); after 48 hours, blood gas analyses showed no statistical difference in any marker (P>0.05). Vital signs during 2-4 hours and 48 hours of treatment showed no statistical difference in either group (P>0.05). The level of peak inspiratory pressure in the experimental group after mechanical ventilation for 2-4 hours and 48 hours was significantly lower than that in the control group (P<0.05), while other variables were not significantly different between groups (P>0.05). Among elderly COPD patients with respiratory failure, application of PRVC resulted in rapid improvement in arterial blood gas analyses while maintaining a low peak inspiratory pressure. PRVC can reduce pulmonary barotrauma

  11. Predictors of extubation failure and reintubation in newborn infants subjected to mechanical ventilation

    PubMed Central

    Costa, Ana Cristina de Oliveira; Schettino, Renata de Carvalho; Ferreira, Sandra Clecêncio

    2014-01-01

    Objective To identify risk factors for extubation failure and reintubation in newborn infants subjected to mechanical ventilation and to establish whether ventilation parameters and blood gas analysis behave as predictors of those outcomes. Methods Prospective study conducted at a neonatal intensive care unit from May to November 2011. A total of 176 infants of both genders subjected to mechanical ventilation were assessed after extubation. Extubation failure was defined as the need to resume mechanical ventilation within less than 72 hours. Reintubation was defined as the need to reintubate the infants any time after the first 72 hours. Results Based on the univariate analysis, the variables gestational age <28 weeks, birth weight <1,000g and low Apgar scores were associated with extubation failure and reintubation. Based on the multivariate analysis, the variables length of mechanical ventilation (days), potential of hydrogen (pH) and partial pressure of oxygen (pO2) remained associated with extubation failure, and the five-minute Apgar score and age at extubation were associated with reintubation. Conclusion Low five-minute Apgar scores, age at extubation, length of mechanical ventilation, acid-base disorders and hyperoxia exhibited associations with the investigated outcomes of extubation failure and reintubation. PMID:24770689

  12. Mechanical ventilation: what have we learned?

    PubMed

    Fenstermacher, Denise; Hong, Dennis

    2004-01-01

    Mechanical ventilation is the second most frequently performed therapeutic intervention after treatment for cardiac arrhythmias in intensive care units today. Countless lives have been saved with its use despite being associated with a greater than 30% in-hospital mortality rate. As life expectancies increase and people with chronic illnesses survive longer, artificial support with mechanical ventilation is also expected to rise. In one survey, over half of senior internal medicine residents reported their training on mechanical ventilation as inadequate, whereas the majority of critical care nurses reported having received no formal education on its use. Technological advances resulting in the availability of sleeker ventilators with graphic waveform displays and new modes of ventilation have challenged the bedside clinicians to incorporate this new data along with evidenced-based research into their daily practice. A review of current thoughts on mechanical ventilation and weaning is presented.

  13. Implications of Natural Occlusion of Ventilated Racks on Ammonia and Sanitation Practices

    PubMed Central

    Creamer, Michelle A; Petty, Joann; Martin, Tara; Bergdall, Valerie; Hickman-Davis, Judy M

    2014-01-01

    Examination of ventilated rat racks prior to semiannual sanitation revealed silicone nozzles and ventilation ports that were partially or completely occluded with granular debris. We subsequently sought to document performance standards for rack sanitation and investigate the effect of ventilation port occlusion on rack function and animal husbandry practices. We hypothesized that individually ventilated cages with occluded airflow would require more frequent cage changes, comparable to those for static cages (that is, every 3 to 4 d). Sprague–Dawley rats were housed under one of 4 conditions: no airflow occlusion, occluded air-supply inlet, occluded air-exhaust outlet, and occlusion of both inlet and outlet. Cages were changed when daily ammonia concentration exceeded 20 ppm or after 14 d had elapsed. Most cages with unoccluded or partial airflow occlusion remained below the 20 ppm limit until day 12 or 13. Cages with occlusion of both inlet and outlet exceeded 20 ppm ammonia by as early as day 5. Airflow was significantly lower in cages with occlusion of both inlet and outlet airflow. Weekly inspection revealed that occlusion of ventilation ports was detectable by 3 mo after semiannual sanitation. This study demonstrates that silicone nozzles should be removed prior to rack sanitation to improve the effectiveness of cleaning ventilation ports and nozzles. While the rack is in use, silicone nozzles and ventilation ports should be inspected regularly to identify occlusion that is likely to diminish environmental quality in the cage. Intracage ammonia levels are significantly higher when both inlet and outlet airflow are occluded. PMID:24602544

  14. Performance of Portable Ventilators at Temperature Extremes

    DTIC Science & Technology

    2015-03-30

    shipped and stored at ambient conditions. The effect of storage at hot and cold temperature extremes on ventilator performance is unknown. We evaluated...The effect of storage at hot and cold temperature extremes on ventilator performance is unknown. We evaluated three portable ventilators currently...operated immediately after 30 minutes of acclimation to room temperature but displayed either a “battery too hot ” or “battery too cold” alert at

  15. Single-lung ventilation in pediatric anesthesia.

    PubMed

    Choudhry, Dinesh K

    2005-12-01

    Single-lung ventilation is requested for an increasing spectrum of surgical procedures in infants and children. A clear understanding of the physiology of single-lung ventilation, the techniques of lung separation, and the technical skill necessary to apply these techniques are essential for an anesthesiologist practicing thoracic anesthesia. This article focuses on various devices available for single-lung ventilation in the pediatric age group, the relevant respiratory physiology, and the strategies that optimize oxygenation during one-lung anesthesia.

  16. 30 CFR 57.8532 - Opening and closing ventilation doors.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Opening and closing ventilation doors. 57.8532... Ventilation Underground Only § 57.8532 Opening and closing ventilation doors. When ventilation control doors...-establish normal ventilation to working places....

  17. 30 CFR 57.8532 - Opening and closing ventilation doors.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Opening and closing ventilation doors. 57.8532... Ventilation Underground Only § 57.8532 Opening and closing ventilation doors. When ventilation control doors...-establish normal ventilation to working places....

  18. 30 CFR 57.8532 - Opening and closing ventilation doors.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Opening and closing ventilation doors. 57.8532... Ventilation Underground Only § 57.8532 Opening and closing ventilation doors. When ventilation control doors...-establish normal ventilation to working places....

  19. 46 CFR 153.312 - Ventilation system standards.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... ventilation system must not allow air to stagnate in any part of a ventilated space. (g) A ventilation system... Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SHIPS... Handling Space Ventilation § 153.312 Ventilation system standards. A cargo handling space...

  20. 46 CFR 153.312 - Ventilation system standards.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... ventilation system must not allow air to stagnate in any part of a ventilated space. (g) A ventilation system... Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SHIPS... Handling Space Ventilation § 153.312 Ventilation system standards. A cargo handling space...

  1. 30 CFR 75.330 - Face ventilation control devices.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Face ventilation control devices. 75.330... SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Ventilation § 75.330 Face ventilation control devices. (a) Brattice cloth, ventilation tubing and other face ventilation control devices shall...

  2. 30 CFR 75.330 - Face ventilation control devices.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Face ventilation control devices. 75.330... SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Ventilation § 75.330 Face ventilation control devices. (a) Brattice cloth, ventilation tubing and other face ventilation control devices shall...

  3. 30 CFR 75.330 - Face ventilation control devices.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Face ventilation control devices. 75.330... SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Ventilation § 75.330 Face ventilation control devices. (a) Brattice cloth, ventilation tubing and other face ventilation control devices shall...

  4. 30 CFR 75.330 - Face ventilation control devices.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Face ventilation control devices. 75.330... SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Ventilation § 75.330 Face ventilation control devices. (a) Brattice cloth, ventilation tubing and other face ventilation control devices shall...

  5. 30 CFR 75.330 - Face ventilation control devices.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Face ventilation control devices. 75.330... SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Ventilation § 75.330 Face ventilation control devices. (a) Brattice cloth, ventilation tubing and other face ventilation control devices shall...

  6. [Comparison of the Effectiveness of Different Supraglottic Ventilation Methods during Bronchial Thermoplasty].

    PubMed

    Wang, Wen; Lin, Jiang-tao; Su, Nan; Nong, Ying; Hong, Hong; Yin, Yi-qing; Li, Cheng-hui

    2016-04-01

    To compare the effectiveness of high-frequency jet ventilation via Wei jet nasal airway and controlled ventilation with improved laryngeal mask airway during bronchial thermoplasty. Twenty-eight patients undergoing bronchial thermoplasty were equally divided into two groups: group A (high-frequency jet ventilation through Wei jet nasal airway) and group B (controlled ventilation with improved laryngeal mask airway). Pulse oxygenation,heart rate,and mean arterial blood pressure were recorded after entering the operating room (T0), 1 minute after administration/induction (T1), bronchoscope inserting (T2), 15 minutes (T3)/30 minutes (T4)/45 minutes (T5) after ventilation,at the end of the operation (T6), and at the recovery of patients' consciousness (T7). The pH,arterial oxygen partial pressure,and arterial carbon dioxide partial pressure were recorded at T0, T4, and T6. The endoscope indwelling duration,operative time,patients' awakening time,adverse events during anesthesia,satisfactions of patients and operators, anesthesic effectiveness were also recorded. The arterial carbon dioxide partial pressur in group A at T4 and T6 were significantly higher than in group B (P<0.05). The pH in group A at T4 and T6 was significantly lower than in group B (P<0.05). The endoscope indwelling duration and the operative time in group B were significantly shorter than in group A (P<0.05) while the recovery of consciousness in group B was significantly longer than in group A (P<0.05). The satisfaction for operators and the efficacy of anesthesia in group B were better than in group A (P<0.05). The number of adverse events in group B was significantly smaller than in group A (P<0.05). The improved laryngeal mask airway with controlled ventilation is more suitable for bronchial thermoplasty.

  7. Initial ventilator settings for critically ill patients.

    PubMed

    Kilickaya, Oguz; Gajic, Ognjen

    2013-03-12

    The lung-protective mechanical ventilation strategy has been standard practice for management of acute respiratory distress syndrome (ARDS) for more than a decade. Observational data, small randomized studies and two recent systematic reviews suggest that lung protective ventilation is both safe and potentially beneficial in patients who do not have ARDS at the onset of mechanical ventilation. Principles of lung-protective ventilation include: a) prevention of volutrauma (tidal volume 4 to 8 ml/kg predicted body weight with plateau pressure<30 cmH2O); b) prevention of atelectasis (positive end-expiratory pressure≥5 cmH2O, as needed recruitment maneuvers); c) adequate ventilation (respiratory rate 20 to 35 breaths per minute); and d) prevention of hyperoxia (titrate inspired oxygen concentration to peripheral oxygen saturation (SpO2) levels of 88 to 95%). Most patients tolerate lung protective mechanical ventilation well without the need for excessive sedation. Patients with a stiff chest wall may tolerate higher plateau pressure targets (approximately 35 cmH2O) while those with severe ARDS and ventilator asynchrony may require a short-term neuromuscular blockade. Given the difficulty in timely identification of patients with or at risk of ARDS and both the safety and potential benefit in patients without ARDS, lung-protective mechanical ventilation is recommended as an initial approach to mechanical ventilation in both perioperative and critical care settings.

  8. Endotoxemia accelerates diaphragm dysfunction in ventilated rabbits.

    PubMed

    Yang, Yi; Yu, Tao; Pan, Chun; Longhini, Federico; Liu, Ling; Huang, Yingzi; Guo, Fengmei; Qiu, Haibo

    2016-12-01

    Ventilators may induce diaphragm dysfunction, and most of the septic population who are admitted to the intensive care unit require mechanical ventilation. However, there is no evidence that sepsis accelerates the onset of ventilator-induced diaphragm dysfunction or affects the microcirculation. Our study investigated whether lipopolysaccharide (LPS)-induced endotoxemia accelerated diaphragm dysfunction in ventilated rabbits by evaluating microcirculation, lipid accumulation, and diaphragm contractility. After anesthesia and tracheostomy, 25 invasively monitored and mechanically ventilated New Zealand white rabbits were randomized to control (n = 5), controlled mechanical ventilation (CMV) (n = 5), pressure support ventilation (PSV; n = 5), CMV or PSV with LPS-induced endotoxemia (CMV-LPS and PSV-LPS, respectively; n = 5 for each). Rabbits were anesthetized and ventilated for 24 h, except the control rabbits (30 min). Diaphragmatic contractility was evaluated using neuromechanical and neuroventilatory efficiency. We evaluated the following at the end of the protocol: (1) diaphragm microcirculation; (2) lipid accumulation; and (3) diaphragm muscular fibers structure. Diaphragm contractility, microcirculation, lipid accumulation, and fiber structures were severely compromised in endotoxemic animals after 24 h compared to nonendotoxemic rabbits. Moreover, a slight but significant increase in lipid accumulation was observed in CMV and PSV groups compared with controls (P < 0.05). Endotoxemia accelerates the diaphragm dysfunction process in ventilated rabbits, affects the microcirculation, and results in diaphragmatic lipid accumulation and contractility impairment. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. Lung-protective ventilation in neonatology.

    PubMed

    van Kaam, Anton

    2011-01-01

    Ventilator-induced lung injury (VILI) is considered an important risk factor in the development of bronchopulmonary dysplasia (BPD) and is primarily caused by overdistension (volutrauma) and repetitive opening and collapse (atelectrauma) of terminal lung units. Lung-protective ventilation should therefore aim to reduce tidal volumes, and recruit and stabilize atelectatic lung units (open lung ventilation strategy). This review will summarize the available evidence on lung-protective ventilation in neonatology, discussing both high-frequency ventilation (HFV) and positive pressure ventilation (PPV). It shows that HFV does not appear to have a clear benefit over PPV, although most studies failed to apply a true open lung ventilation strategy during HFV. The evidence on the optimal tidal volume, positive end-expiratory pressure and the role for lung recruitment during lung-protective PPV is extremely limited. Volume-targeted ventilation seems to be a promising mode in terms of lung protection, but more studies are needed. Due to the lack of convincing evidence, lung-protective ventilation and modes seem to be implemented in daily clinical practice at a slow pace.

  10. [VENTILOP survey. Survey in peroperative mechanical ventilation].

    PubMed

    Fischer, F; Collange, O; Mahoudeau, G; Simon, M; Moussa, H; Thibaud, A; Steib, A; Pottecher, T; Mertes, M

    2014-06-01

    Mechanical ventilation can initiate ventilator-associated lung injury and postoperative pulmonary complications. The aim of this study was to evaluate (1) how mechanical ventilation was comprehended by anaesthetists (physician and nurses) and (2) the need for educational programs. A computing questionnary was sent by electronic-mail to the entire anaesthetist from Alsace region in France (297 physicians), and to a pool of 99 nurse anaesthetists. Mechanical ventilation during anaesthesia was considered as optimized when low tidal volume (6-8mL) of ideal body weight was associated with positive end expiratory pressure, FiO2 less than 50%, I/E adjustment and recruitment maneuvers. The participation rate was 50.5% (172 professionals). Only 2.3% of professionals used the five parameters for optimized ventilation. Majority of professionals considered that mechanical ventilation adjustment influenced the patients' postoperative outcome. Majority of the professionals asked for a specific educational program in the field of mechanical ventilation. Only 2.3% of professionals optimized mechanical ventilation during anaesthesia. Guidelines and specific educational programs in the field of mechanical ventilation are widely expected. Copyright © 2014 Société française d’anesthésie et de réanimation (Sfar). Published by Elsevier SAS. All rights reserved.

  11. Seasonal Temperature Variations controlling Cave Ventilation Processes in Cueva Larga, Puerto Rico

    NASA Astrophysics Data System (ADS)

    Winter, A.; Vieten, R.; Warken, S. F.; Schrӧder-Ritzrau, A.; Miller, T. E.; Scholz, D.

    2016-12-01

    Two years of monthly monitoring result in much better understanding of ventilation processes in caves. Cueva Larga, a tropical cave in Puerto Rico is 1440 m long with a large main passage (about 116,000 m3). Cave air pCO2 in the main passage varied seasonally, between 600 ppm in winter and 1800 ppm in summer. The seasonal variability in cave pCO2 made it possible to estimate a cave air exchange time of 36±5 days and a winter ventilation rate of 3,200±800 m3/day for the main cave passage. Calculations of virtual temperature and differences between cave and surface temperature show that the seasonal temperature cycle is the main driver of the alternation between a well-ventilated winter mode and a near-stagnant summer mode. The winter mode is characterized by a positive buoyancy contrast at night leading to maximal cave ventilation, while during summer ventilation is at a minimum. Between winter and summer, a transitional mode of partial cave ventilation is observed. On shorter time scales (diurnal to weekly), cave pCO2 is also influenced by atmospheric pressure but this variation is one order of magnitude lower than the seasonal pCO2 change. The cave morphology of Cueva Larga including its large volume, tubular shape and the obstructed cave entrance geometry are important boundary conditions for the observed ventilation patterns. Our findings emphasize that cave systems with varying morphology have to be studied individually in order to correctly describe ventilation processes.

  12. [ASSESSMENT OF PULMONARY VENTILATION FUNCTION AT INTENSIVE CARE UNIT PATIENTS].

    PubMed

    Mustafin, R; Bakirov, A

    2015-09-01

    The article presents the functional characteristics of lung tissue in reanimation profile patients with different pathologies with forced ventilation and auxiliary support on the background. The aim of this study was to analyze the dynamics properties of lung tissue in intensive care unit patients with symptoms of severe violations of restrictive lung tissue being on ventilatory support. Results were subjected to analysis of acid-base status and dynamics of the main indicators of the biomechanical properties of the lung in 32 patients with severe concomitant injury (n=21), acute bilateral community-acquired pneumonia (n=7), septic shock (n=4) during the entire period of the respiratory "prosthetics "(before and after the beginning of mechanical ventilation). Using during ventilatory support of patients with initial symptoms of the syndrome of acute lung damage and reduced lung function restrictive positive end-expiratory pressure of 6-10 cm of water column when the conventional (1:2; 1:2.5 at p≤0.05) and invert (2:1 at p≤0,1) ratio inhale/exhale, relatively low tidal volume (6-8 ml/kg) allows increase the compliance of the lung tissue to 11-29%. Increased expiratory time constant has a direct correlation with the value of airway resistance was due not only to the maintenance of optimal parameters for MVV (mechanical voluntary ventilation), but regular lavage of the tracheobronchial tree, which allows to maintain patency of the lower respiratory tract. The main areas during mechanical ventilation of lungs in patients with a sharp decline in restrictive lung function (ARDS, pneumonia), regardless of the reason it was summoned, optimal value is the observance of the positive end-expiratory pressure, the ratio of inhale/exhale (depending on the degree of hypoxemia), to maintain sufficient blood oxygen saturation and partial pressure of oxygen in the blood plasma.

  13. 46 CFR 111.103-1 - Power ventilation systems except machinery space ventilation systems.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... not apply to closed ventilation systems for motors or generators, diffuser fans for refrigerated... 46 Shipping 4 2011-10-01 2011-10-01 false Power ventilation systems except machinery space ventilation systems. 111.103-1 Section 111.103-1 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY...

  14. 46 CFR 111.103-1 - Power ventilation systems except machinery space ventilation systems.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... not apply to closed ventilation systems for motors or generators, diffuser fans for refrigerated... 46 Shipping 4 2010-10-01 2010-10-01 false Power ventilation systems except machinery space ventilation systems. 111.103-1 Section 111.103-1 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY...

  15. 46 CFR 111.103-1 - Power ventilation systems except machinery space ventilation systems.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Power ventilation systems except machinery space ventilation systems. 111.103-1 Section 111.103-1 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Remote Stopping Systems § 111.103-1 Power ventilation systems except machinery...

  16. Vagal denervation inhibits the increase in pulmonary blood flow during partial lung aeration at birth.

    PubMed

    Lang, Justin A R; Pearson, James T; Binder-Heschl, Corinna; Wallace, Megan J; Siew, Melissa L; Kitchen, Marcus J; Te Pas, Arjan B; Lewis, Robert A; Polglase, Graeme R; Shirai, Mikiyasu; Hooper, Stuart B

    2017-03-01

    Lung aeration at birth significantly increases pulmonary blood flow, which is unrelated to increased oxygenation or other spatial relationships that match ventilation to perfusion. Using simultaneous X-ray imaging and angiography in near-term rabbits, we investigated the relative contributions of the vagus nerve and oxygenation to the increase in pulmonary blood flow at birth. Vagal denervation inhibited the global increase in pulmonary blood flow induced by partial lung aeration, although high inspired oxygen concentrations can partially mitigate this effect. The results of the present study indicate that a vagal reflex may mediate a rapid global increase in pulmonary blood flow in response to partial lung aeration. Air entry into the lungs at birth triggers major cardiovascular changes, including a large increase in pulmonary blood flow (PBF) that is not spatially related to regional lung aeration. To investigate the possible underlying role of a vagally-mediated stimulus, we used simultaneous phase-contrast X-ray imaging and angiography in near-term (30 days of gestation) vagotomized (n = 15) or sham-operated (n = 15) rabbit kittens. Rabbits were imaged before ventilation, when one lung was ventilated (unilateral) with 100% nitrogen (N2 ), air or 100% oxygen (O2 ), and after all kittens were switched to unilateral ventilation in air and then ventilation of both lungs using air. Compared to control kittens, vagotomized kittens had little or no increase in PBF in both lungs following unilateral ventilation when ventilation occurred with 100% N2 or with air. However, relative PBF did increase in vagotomized animals ventilated with 100% O2 , indicating the independent stimulatory effects of local oxygen concentration and autonomic innervation on the changes in PBF at birth. These findings demonstrate that vagal denervation inhibits the previously observed increase in PBF with partial lung aeration, although high inspired oxygen concentrations can partially

  17. [Evaluation of patient-ventilator synchrony of three new types of ventilators with pressure sunnort ventilation mode].

    PubMed

    Zhou, Juan; Wu, Hao; Cao, Desen

    2014-08-01

    Pressure-support ventilation (PSV) is a form of important ventilation mode. Patient-ventilator synchrony of pressure support ventilation can be divided into inspiration-triggered and expiration-triggered ones. Whether the ventilator can track the patient's inspiration and expiration very well or not is an important evaluating item of the performance of the ventilator. The ventilator should response to the patient's inspiration effort on time and deliver the air flow to the patient under various conditions, such as different patient's lung types and inspiration effort, etc. Similarly, the ventilator should be able to response to the patient's expiration action, and to decrease the patient lung's internal pressure rapidly. Using the Active Servo Lung (ASL5000) respiratory simulation system, we evaluated the spontaneous breathing of PSV mode on E5, Servo i and Evital XL. The following parameters, the delay time before flow to the patient starts once the trigger variable signaling the start of inspiration, the lowest inspiratory airway pressure generated prior to the initiation of PSV, etc. were measured.

  18. High frequency jet ventilation and intermittent positive pressure ventilation. Effect of cerebral blood flow in patients after open heart surgery

    SciTech Connect

    Pittet, J.F.; Forster, A.; Suter, P.M. )

    1990-02-01

    Attenuation of ventilator-synchronous pressure fluctuations of intracranial pressure has been demonstrated during high frequency ventilation in animal and human studies, but the consequences of this effect on cerebral blood flow have not been investigated in man. We compared the effects of high frequency jet ventilation and intermittent positive pressure ventilation on CBF in 24 patients investigated three hours after completion of open-heart surgery. The patients were investigated during three consecutive periods with standard sedation (morphine, pancuronium): a. IPPV; b. HFJV; c. IPPV. Partial pressure of arterial CO{sub 2} (PaCO{sub 2}: 4.5-5.5 kPa) and rectal temperature (35.5 to 37.5{degree}C) were maintained constant during the study. The CBF was measured by intravenous {sup 133}Xe washout technique. The following variables were derived from the cerebral clearance of {sup 133}Xe: the rapid compartment flow, the initial slope index, ie, a combination of the rapid and the slow compartment flows, and the ratio of fast compartment flow over total CBF (FF). Compared to IPPV, HFJV applied to result in the same mean airway pressure did not produce any change in pulmonary gas exchange, mean systemic arterial pressure, and cardiac index. Similarly, CBF was not significantly altered by HFJV. However, important variations of CBF values were observed in three patients, although the classic main determinants of CBF (PaCO{sub 2}, cerebral perfusion pressure, Paw, temperature) remained unchanged. Our results suggest that in patients with normal systemic hemodynamics, the effects of HFJV and IPPV on CBF are comparable at identical levels of mean airway pressure.

  19. Effect of plasma carbonic anhydrase on ventilation in exercising dogs.

    PubMed

    Lewis, S M; Hill, E P

    1980-10-01

    Recent studies suggest pH sampled by arterial chemoreceptors may not equal that sampled by external pH electrodes, because the uncatalyzed hydration of CO2 in plasma is a slow reaction (t 1/2 approximately 9 S). The importance of this reaction rate to ventilatory control (particularly during exercise) is not known. We studied the effect of catalyzing the CO2-pH reaction in three awake exercising dogs with chronic tracheostomies and carotid loops; the dogs were trained to run on a treadmill. Respiration frequency, tidal volume, total ventilation, and end-tidal partial pressure of CO2 (PCO2) were continuously monitored. Periodically, carotid artery blood was drawn and analyzed for partial pressure of O2 (PO2), PCO2, pH, and plasma carbonic anhydrase (CA) activity. Measurements were made during steady-state exercise (3 mph and 10% grade), during a control period, after injection of a 5 ml bolus of saline, and after injection of 5 mg/kg of bovine CA dissolved in 5 ml of saline. This dose of CA increased the reaction rate by more than 80-fold. Neither the control nor the CA injections significantly altered the ventilatory parameters. Saline and CA date differed by less than 5% in ventilation, 1 Torr in arterial PCO2, 0.01 in pH units, and 1.5 Torr in end-tidal PCO2. Thus the of CO2 hydration in plasma is not a significant factor in ventilatory control.

  20. Identification and analysis of the maize P700 chlorophyll a apoproteins PSI-A1 and PSI-A2 by high pressure liquid chromatography analysis and partial sequence determination.

    PubMed

    Fish, L E; Bogorad, L

    1986-06-25

    We recently described a pair of partially homologous maize chloroplast genes, one of which was shown to code for an apoprotein of the P700 chlorophyll a complex of photosystem I (Fish, L.E., Kück, U., and Bogorad, L. (1985) J. Biol. Chem. 260, 1413-1421). Two chlorophyll-free apoprotein bands from maize chlorophyll-protein complex I (CPI) can be resolved on lithium dodecyl sulfate (LDS)-urea polyacrylamide gels. Proteins in both bands react with antibodies prepared against CPI, but antibodies prepared against two synthetic peptides corresponding to predicted sequences of PSI-A1 react only with the upper band. The presence of products of the two genes, ps1A1 and ps1A2, in CPI was verified by analysis of cyanogen bromide (CNBr) fragments of the lower apoprotein band obtained from LDS-urea polyacrylamide gels by reverse-phase high pressure liquid chromatography. Amino-terminal sequencing of five CNBr fragments indicates that the lower band contains a product of the ps1A2 gene. The possibility of extensive processing was investigated because the apparent molecular masses of the maize CPI proteins are about 58-70 kDa on LDS-polyacrylamide gels rather than the predicted sizes of about 83 kDa. Antibodies against a synthetic peptide corresponding to a predicted sequence in PSI-A1 were used to determine that the amino-terminal end of PSI-A1 is intact beyond about position 52. The amino-terminal CNBr fragment of PSI-A2 was identified by sequencing, indicating that the amino-terminal end of PSI-A2 is not processed. The carboxyl-terminal CNBr fragment of PSI-A2 was also identified by sequencing. These results indicate that the PSI-A1 and PSI-A2 polypeptides are not extensively processed, although some processing at the carboxyl-terminal end has not been ruled out.

  1. Ventilator-induced Lung Injury

    PubMed Central

    Kneyber, Martin C. J.; Zhang, Haibo; Slutsky, Arthur S.

    2016-01-01

    It is well established that mechanical ventilation can injure the lung, producing an entity known as ventilator-induced lung injury (VILI). There are various forms of VILI, including volutrauma (i.e., injury caused by overdistending the lung), atelectrauma (injury due to repeated opening/closing of lung units), and biotrauma (release of mediators that can induce lung injury or aggravate pre-existing injury, potentially leading to multiple organ failure). Experimental data in the pediatric context are in accord with the importance of VILI, and appear to show age-related susceptibility to VILI, although a conclusive link between use of large Vts and mortality has not been demonstrated in this population. The relevance of VILI in the pediatric intensive care unit population is thus unclear. Given the physiological and biological differences in the respiratory systems of infants, children, and adults, it is difficult to directly extrapolate clinical practice from adults to children. This Critical Care Perspective analyzes the relevance of VILI to the pediatric population, and addresses why pediatric patients might be less susceptible than adults to VILI. PMID:25003705

  2. Manual resuscitators and portable ventilators.

    PubMed

    Phillips, G D; Skowronski, G A

    1986-08-01

    This paper reviews the state of the art in Australia of manually operated, self-inflating bag resuscitators, including the Laerdal, Air Viva and Ambu; manually operated bags dependent upon an oxygen supply, including Mapleson B, C, E and F, the CIG Medishield Oxy-Saver and modified Oxy-Viva Resuscitator 3, and the Komesaroff Oxy-Resuscitator RD85; oxygen-powered resuscitators, including the Oxy-Viva Resuscitator 3 with Demand and RM2 Valves, and the Oxylife FM85; and portable ventilators, including the Drager Oxylog, and Ohmeda Logic 07. Specific comment is made to the effect that the design of the resuscitator is often less important than the knowledge and ability of the operator in using the equipment to achieve adequate lung ventilation. The simplest, cheapest, most useful resuscitators are the manually operated self-inflating bag assemblies. With special training, use of more complex equipment can be justified in some circumstances. The more complex the equipment, the greater the risk of inappropriate use, and the greater the risk of equipment malfunction unless a regular maintenance program is followed.

  3. History of Mechanical Ventilation. From Vesalius to Ventilator-induced Lung Injury.

    PubMed

    Slutsky, Arthur S

    2015-05-15

    Mechanical ventilation is a life-saving therapy that catalyzed the development of modern intensive care units. The origins of modern mechanical ventilation can be traced back about five centuries to the seminal work of Andreas Vesalius. This article is a short history of mechanical ventilation, tracing its origins over the centuries to the present day. One of the great advances in ventilatory support over the past few decades has been the development of lung-protective ventilatory strategies, based on our understanding of the iatrogenic consequences of mechanical ventilation such as ventilator-induced lung injury. These strategies have markedly improved clinical outcomes in patients with respiratory failure.

  4. Role of the JNK pathway on the expression of inflammatory factors in alveolar macrophages under mechanical ventilation.

    PubMed

    Tong, Jin; Zhou, Xiang-Dong; Kolosov, Victor P; Perelman, Juliy M

    2013-11-01

    The aim of this study was to investigate the regulatory role of the c-JUN N-terminal kinase (JNK) pathway on interleukin (IL)-8 and tumor necrosis factor (TNF)-α expression in alveolar macrophages (AMs) of injured lung. Lung injury was induced in the New Zealand white rabbit by applying continuous mechanical ventilation with or without inhibitor of JNK (SP600125), p38 (SB203580), or ERK (PD98059). Non-ventilated rabbits (controls) were compared with the different ventilation-days groups, and untreated rabbits ventilated for 3 days (controls) were compared with the different inhibitor groups. We found that mechanical ventilation caused significant decreases in partial pressures of carbon dioxide (pCO2) and oxygen (pO2) of untreated rabbits (all times, P<0.05), but the inhibitor-treated groups showed no change in either blood-gas indicator (all times, P>0.05). Mechanical ventilation caused time-dependent increases in mRNA and protein levels of TNF-α and IL-8 in AMs and in serum of untreated rabbits, with the peak levels occurring at day 3 of ventilation. The SP600125-treated group showed significantly decreased TNF-α expression, but no significant change in IL-8 expression. Neither the SB203580- nor PD98059-treated groups showed any significant change in TNF-α or IL-8 expression. MAPKs' inhibitors could reduce mechanical ventilation-induced inflammation, and SP600125 produced the most robust decrease in inflammation. Mechanical ventilation-induced lung injury stimulates IL-8 and TNF-α expression in rabbit AMs in a time-dependent manner. The JNK pathway plays an important role in mechanical ventilation-stimulated TNF-α expression in AMs, but the injury-stimulated IL-8 expression may be regulated by other signaling pathways.

  5. 14 CFR 252.9 - Ventilation systems.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 4 2013-01-01 2013-01-01 false Ventilation systems. 252.9 Section 252.9 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) ECONOMIC REGULATIONS SMOKING ABOARD AIRCRAFT § 252.9 Ventilation systems. Air carriers shall prohibit smoking...

  6. 14 CFR 252.9 - Ventilation systems.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 4 2014-01-01 2014-01-01 false Ventilation systems. 252.9 Section 252.9 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) ECONOMIC REGULATIONS SMOKING ABOARD AIRCRAFT § 252.9 Ventilation systems. Air carriers shall prohibit smoking...

  7. 14 CFR 252.9 - Ventilation systems.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 4 2012-01-01 2012-01-01 false Ventilation systems. 252.9 Section 252.9 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) ECONOMIC REGULATIONS SMOKING ABOARD AIRCRAFT § 252.9 Ventilation systems. Air carriers shall prohibit smoking...

  8. 14 CFR 252.9 - Ventilation systems.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Ventilation systems. 252.9 Section 252.9 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) ECONOMIC REGULATIONS SMOKING ABOARD AIRCRAFT § 252.9 Ventilation systems. Air carriers shall prohibit smoking...

  9. 14 CFR 252.9 - Ventilation systems.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 4 2011-01-01 2011-01-01 false Ventilation systems. 252.9 Section 252.9 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) ECONOMIC REGULATIONS SMOKING ABOARD AIRCRAFT § 252.9 Ventilation systems. Air carriers shall prohibit smoking...

  10. 46 CFR 111.105-21 - Ventilation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Ventilation. 111.105-21 Section 111.105-21 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL... location has the classification of that location. Each fan for ventilation of a hazardous location must be...

  11. 46 CFR 111.105-21 - Ventilation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Ventilation. 111.105-21 Section 111.105-21 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL... location has the classification of that location. Each fan for ventilation of a hazardous location must be...

  12. 29 CFR 1926.57 - Ventilation.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 8 2011-07-01 2011-07-01 false Ventilation. 1926.57 Section 1926.57 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Occupational Health and Environmental Controls § 1926.57 Ventilation. (a) General. Whenever...

  13. Commissioning Ventilated Containment Systems in the Laboratory

    SciTech Connect

    Not Available

    2008-08-01

    This Best Practices Guide focuses on the specialized approaches required for ventilated containment systems, understood to be all components that drive and control ventilated enclosures and local exhaust systems within the laboratory. Geared toward architects, engineers, and facility managers, this guide provides information about technologies and practices to use in designing, constructing, and operating operating safe, sustainable, high-performance laboratories.

  14. Preoperational test report, primary ventilation system

    SciTech Connect

    Clifton, F.T.

    1997-11-04

    This represents a preoperational test report for Primary Ventilation Systems, Project W-030. Project W-030 provides a ventilation upgrade for the four Aging Waste Facility tanks. The system provides vapor space filtered venting of tanks AY101, AY102, AZ101, AZ102. The tests verify correct system operation and correct indications displayed by the central Monitor and Control System.

  15. 46 CFR 116.610 - Ventilation ducts.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... served by the ventilation duct for shutting off the passage of air through the ventilation duct in the... side of the boundary. A fire damper blade need not be insulated; and (7) Ducts serving cargo spaces... at least 11 USSG and not more than 3.2 millimeters (0.125 inch) gap between the blade and casing; (2...

  16. 14 CFR 23.831 - Ventilation.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... ventilation system must be designed to provide each occupant with at least 0.55 pounds of fresh air per minute... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Ventilation. 23.831 Section 23.831... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Design and Construction Personnel...

  17. 29 CFR 1910.94 - Ventilation.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... sizes capable of passing through the upper respiratory system to reach the lower lung passages. (xi... handled by an exhaust ventilation system. (viii) Exhaust ventilation system. A system for removing... in automatic systems. Where flammable or explosive dust mixtures may be present, the construction...

  18. 29 CFR 1910.94 - Ventilation.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... sizes capable of passing through the upper respiratory system to reach the lower lung passages. (xi... handled by an exhaust ventilation system. (viii) Exhaust ventilation system. A system for removing... in automatic systems. Where flammable or explosive dust mixtures may be present, the construction...

  19. 29 CFR 1910.94 - Ventilation.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... sizes capable of passing through the upper respiratory system to reach the lower lung passages. (xi... handled by an exhaust ventilation system. (viii) Exhaust ventilation system. A system for removing... in automatic systems. Where flammable or explosive dust mixtures may be present, the construction...

  20. 24 CFR 3285.505 - Crawlspace ventilation.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...) of the home's floor area. The total area of ventilation openings may be reduced to one square foot (ft.2) for every 1,500 square feet (ft.2) of the home's floor area, where a uniform 6-mil polyethylene... surface beneath the entire floor area of the home. (b) Ventilation openings must be placed as high...

  1. Infiltration in ASHRAE's Residential Ventilation Standards

    SciTech Connect

    Sherman, Max

    2008-10-01

    The purpose of ventilation is to dilute or remove indoor contaminants that an occupant could be exposed to. It can be provided by mechanical or natural means. ASHRAE Standards including standards 62, 119, and 136 have all considered the contribution of infiltration in various ways, using methods and data from 20 years ago. The vast majority of homes in the United States and indeed the world are ventilated through natural means such as infiltration caused by air leakage. Newer homes in the western world are tight and require mechanical ventilation. As we seek to provide acceptable indoor air quality at minimum energy cost, it is important to neither over-ventilate norunder-ventilate. Thus, it becomes critically important to correctly evaluate the contribution infiltration makes to both energy consumption and equivalent ventilation. ASHRAE Standard 62.2 specifies how much mechanical ventilation is considered necessary to provide acceptable indoor air quality, but that standard is weak on how infiltration can contribute towards meeting the total requirement. In the past ASHRAE Standard 136 was used to do this, but new theoretical approaches and expanded weather data have made that standard out of date. This article will describe how to properly treat infiltration as an equivalent ventilation approach and then use new data and these new approaches to demonstrate how these calculations might be done both in general and to update Standard 136.

  2. 14 CFR 121.219 - Ventilation.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 3 2014-01-01 2014-01-01 false Ventilation. 121.219 Section 121.219 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR CARRIERS..., FLAG, AND SUPPLEMENTAL OPERATIONS Special Airworthiness Requirements § 121.219 Ventilation....

  3. 14 CFR 121.219 - Ventilation.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 false Ventilation. 121.219 Section 121.219 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR CARRIERS..., FLAG, AND SUPPLEMENTAL OPERATIONS Special Airworthiness Requirements § 121.219 Ventilation....

  4. 14 CFR 121.219 - Ventilation.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 false Ventilation. 121.219 Section 121.219 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR CARRIERS..., FLAG, AND SUPPLEMENTAL OPERATIONS Special Airworthiness Requirements § 121.219 Ventilation....

  5. 14 CFR 121.219 - Ventilation.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Ventilation. 121.219 Section 121.219 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR CARRIERS..., FLAG, AND SUPPLEMENTAL OPERATIONS Special Airworthiness Requirements § 121.219 Ventilation....

  6. 14 CFR 23.831 - Ventilation.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Ventilation. 23.831 Section 23.831 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS... Cargo Accommodations § 23.831 Ventilation. (a) Each passenger and crew compartment must be...

  7. 14 CFR 121.219 - Ventilation.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Ventilation. 121.219 Section 121.219 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR CARRIERS..., FLAG, AND SUPPLEMENTAL OPERATIONS Special Airworthiness Requirements § 121.219 Ventilation....

  8. 46 CFR 72.05-50 - Ventilation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 3 2012-10-01 2012-10-01 false Ventilation. 72.05-50 Section 72.05-50 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PASSENGER VESSELS CONSTRUCTION AND ARRANGEMENT Structural Fire Protection § 72.05-50 Ventilation. (a) Where the term duct is used in this section, it shall...

  9. 21 CFR 868.5895 - Continuous ventilator.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Continuous ventilator. 868.5895 Section 868.5895 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED..., pediatric, and neonatal ventilators are included in this generic type of device. (b) Classification. Class...

  10. Tracheostomy tube enabling speech during mechanical ventilation.

    PubMed

    Nomori, Hiroaki

    2004-03-01

    A voice tracheostomy tube (VTT) was developed to enable patients to speak during mechanical ventilation. The VTT has slits cut in it and is covered on part of its side with an elastic cuff, enabling the cuff to expand with positive pressure from the ventilator on inspiration and to deflate on expiration. By this mechanism, inspired air from the ventilator goes to the lung with the cuff inflated, and some of the expired air passes out around the deflated cuff and discharges through the glottis, allowing sufficient ventilation and also enabling vocal fold vibration. An experiment using a model lung showed that there was little leakage on inspiration even for low lung compliance and high airway pressure, and that the leakage volume on expiration was approximately 40% of the ventilated volume, ie, the volume discharging through the vocal fold in clinical use. Sixteen patients who had been managed by ventilation via a conventional tracheostomy tube were switched to the VTT. All patients except one were able to speak after switching to the VTT without change in PaO(2) and PaCO(2). There were no complications associated with the use of the VTT. Bronchoscopy showed that the cuff of the VTT did not damage the tracheal mucosa. The VTT enables patients to speak during mechanical ventilation with sufficient ventilation and without aspiration and damage to the tracheal mucosa, even in patients with low lung compliance.

  11. New evidence in one-lung ventilation.

    PubMed

    Meleiro, H; Correia, I; Charco Mora, P

    2017-09-26

    Mechanical ventilation in thoracic surgery has undergone significant changes in recent years due to the implementation of the protective ventilation. This review will analyze recent ventilatory strategies in one-lung ventilation. A MEDLINE research was performed using Mesh term "One-Lung Ventilation" including randomized clinical trials, metanalysis, reviews and systematic reviews published in the last 6 years. Search was performed on 21st March 2017. A total of 75 articles were initially found. After title and abstract review 14 articles were included. Protective ventilation is not simply synonymous of low tidal volume ventilation, but it also includes routine use of PEEP and alveolar recruitment maneuver. New techniques are still in discussion namely PEEP adjustment, ratio inspiration:expiration, ideal type of anesthesia during one-lung ventilation and hypercapnic ventilation. Copyright © 2017 Sociedad Española de Anestesiología, Reanimación y Terapéutica del Dolor. Publicado por Elsevier España, S.L.U. All rights reserved.

  12. 24 CFR 3285.505 - Crawlspace ventilation.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... provide cross-ventilation. (d) Ventilation openings must be covered for their full height and width with a... the home are accessible. (f) Dryer vents and combustion air inlets must pass through the skirting to the outside. Any surface water runoff from the furnace, air conditioning, or water heater drains must...

  13. 46 CFR 194.10-25 - Ventilation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... CONTROL OF EXPLOSIVES AND OTHER HAZARDOUS MATERIALS Magazines § 194.10-25 Ventilation. (a) Integral magazines. (1) All integral magazines shall be provided with natural or mechanical ventilation. Design calculations shall be submitted demonstrating that the system has sufficient capacity to maintain the...

  14. 46 CFR 194.10-25 - Ventilation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... CONTROL OF EXPLOSIVES AND OTHER HAZARDOUS MATERIALS Magazines § 194.10-25 Ventilation. (a) Integral magazines. (1) All integral magazines shall be provided with natural or mechanical ventilation. Design calculations shall be submitted demonstrating that the system has sufficient capacity to maintain the...

  15. 46 CFR 194.10-25 - Ventilation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... CONTROL OF EXPLOSIVES AND OTHER HAZARDOUS MATERIALS Magazines § 194.10-25 Ventilation. (a) Integral magazines. (1) All integral magazines shall be provided with natural or mechanical ventilation. Design calculations shall be submitted demonstrating that the system has sufficient capacity to maintain the...

  16. 46 CFR 194.10-25 - Ventilation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... CONTROL OF EXPLOSIVES AND OTHER HAZARDOUS MATERIALS Magazines § 194.10-25 Ventilation. (a) Integral magazines. (1) All integral magazines shall be provided with natural or mechanical ventilation. Design calculations shall be submitted demonstrating that the system has sufficient capacity to maintain the...

  17. 46 CFR 194.10-25 - Ventilation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... CONTROL OF EXPLOSIVES AND OTHER HAZARDOUS MATERIALS Magazines § 194.10-25 Ventilation. (a) Integral magazines. (1) All integral magazines shall be provided with natural or mechanical ventilation. Design calculations shall be submitted demonstrating that the system has sufficient capacity to maintain the...

  18. New modes of assisted mechanical ventilation.

    PubMed

    Suarez-Sipmann, F

    2014-05-01

    Recent major advances in mechanical ventilation have resulted in new exciting modes of assisted ventilation. Compared to traditional ventilation modes such as assisted-controlled ventilation or pressure support ventilation, these new modes offer a number of physiological advantages derived from the improved patient control over the ventilator. By implementing advanced closed-loop control systems and using information on lung mechanics, respiratory muscle function and respiratory drive, these modes are specifically designed to improve patient-ventilator synchrony and reduce the work of breathing. Depending on their specific operational characteristics, these modes can assist spontaneous breathing efforts synchronically in time and magnitude, adapt to changing patient demands, implement automated weaning protocols, and introduce a more physiological variability in the breathing pattern. Clinicians have now the possibility to individualize and optimize ventilatory assistance during the complex transition from fully controlled to spontaneous assisted ventilation. The growing evidence of the physiological and clinical benefits of these new modes is favoring their progressive introduction into clinical practice. Future clinical trials should improve our understanding of these modes and help determine whether the claimed benefits result in better outcomes. Copyright © 2013 Elsevier España, S.L. and SEMICYUC. All rights reserved.

  19. Partial breast brachytherapy

    MedlinePlus

    ... brachytherapy; Accelerated partial breast irradiation - brachytherapy; Partial breast radiation therapy - brachytherapy; Permanent breast seed implant; PBSI; Low-dose radiotherapy - breast; High-dose radiotherapy - breast; Electronic balloon ...

  20. Mine ventilation and air conditioning. 3. edition

    SciTech Connect

    Hartman, H.L.; Mutmansky, J.M.; Ramani, R.V.; Wang, Y.J.

    1998-12-31

    This revised edition presents an engineering design approach to ventilation and air conditioning as part of the comprehensive environmental control of the mine atmosphere. It provides an in-depth look, for practitioners who design and operate mines, into the health and safety aspects of environmental conditions in the underground workplace. The contents include: Environmental control of the mine atmosphere; Properties and behavior of air; Mine air-quality control; Mine gases; Dusts and other mine aerosols; Mine ventilation; Airflow through mine openings and ducts; Mine ventilation circuits and networks; Natural ventilation; Fan application to mines; Auxiliary ventilation and controlled recirculation; Economics of airflow; Control of mine fires and explosions; Mine air conditioning; Heat sources and effect in mines; Mine air conditioning systems; Appendices; References; Answers to selected problems; and Index.

  1. Mechanical Ventilation: State of the Art.

    PubMed

    Pham, Tài; Brochard, Laurent J; Slutsky, Arthur S

    2017-09-01

    Mechanical ventilation is the most used short-term life support technique worldwide and is applied daily for a diverse spectrum of indications, from scheduled surgical procedures to acute organ failure. This state-of-the-art review provides an update on the basic physiology of respiratory mechanics, the working principles, and the main ventilatory settings, as well as the potential complications of mechanical ventilation. Specific ventilatory approaches in particular situations such as acute respiratory distress syndrome and chronic obstructive pulmonary disease are detailed along with protective ventilation in patients with normal lungs. We also highlight recent data on patient-ventilator dyssynchrony, humidified high-flow oxygen through nasal cannula, extracorporeal life support, and the weaning phase. Finally, we discuss the future of mechanical ventilation, addressing avenues for improvement. Copyright © 2017 Mayo Foundation for Medical Education and Research. Published by Elsevier Inc. All rights reserved.

  2. Lake Superior Ventilation and Dissolved Oxygen Cycle

    NASA Astrophysics Data System (ADS)

    Matsumoto, K.; Tokos, K.; Gregory, C.

    2016-02-01

    Lake Superior is one of the largest lakes in world yet its circulation, especially in the interior, is not well understood. Ventilation rate of the lake interior is key to determining the vertical distribution and fate of natural and anthropogenic tracers. In this study, we utilize "age" and "dye" tracers in a realistically configured numerical model of Lake Superior to characterize its ventilation. We find that Lake Superior is preferentially ventilated over rough bathymetry and that spring overturn following a very cold winter does not completely ventilate the interior. Also, dissolved oxygen in Lake Superior is not a good proxy of ventilation age, as expected from oceanography, because the lake is so strongly physically dominated.

  3. Fifty Years of Research in ARDS. Spontaneous Breathing during Mechanical Ventilation. Risks, Mechanisms, and Management.

    PubMed

    Yoshida, Takeshi; Fujino, Yuji; Amato, Marcelo B P; Kavanagh, Brian P

    2017-04-15

    Spontaneous respiratory effort during mechanical ventilation has long been recognized to improve oxygenation, and because oxygenation is a key management target, such effort may seem beneficial. Also, disuse and loss of peripheral muscle and diaphragm function is increasingly recognized, and thus spontaneous breathing may confer additional advantage. Reflecting this, epidemiologic data suggest that the use of partial (vs. full) support modes of ventilation is increasing. Notwithstanding the central place of spontaneous breathing in mechanical ventilation, accumulating evidence indicates that it may cause-or worsen-acute lung injury, especially if acute respiratory distress syndrome is severe and spontaneous effort is vigorous. This Perspective reviews the evidence for this phenomenon, explores mechanisms of injury, and provides suggestions for clinical management and future research.

  4. Arterial oxygen desaturation during one-lung ventilation in a patient with segmental pulmonary infarction.

    PubMed

    Pfitzner, J; Lance, D G; Peacocks, M J

    2005-12-01

    A left thoracotomy for decortication of an infected haemothorax was performed on a 52-year-old man with a partially infarcted left lower lobe that occurred as a rare complication of a pulmonary venous embolus. Before the completion of surgery, after an uncomplicated 40 minutes of one-lung ventilation, the left lung was temporarily re-expanded to assess air leak. On the resumption of one-lung ventilation the SpO2 fell rapidly to 85%, despite apnoeic oxygenation of the non-ventilated lung. In the absence of evidence of double-lumen tube displacement, intra-pulmonary shunting as a consequence of impaired hypoxic pulmonary vasoconstriction in the newly expanded markedly pathological lung is considered the most likely mechanism.

  5. Mechanical ventilation during extracorporeal membrane oxygenation

    PubMed Central

    2014-01-01

    The timing of extracorporeal membrane oxygenation (ECMO) initiation and its outcome in the management of respiratory and cardiac failure have received considerable attention, but very little attention has been given to mechanical ventilation during ECMO. Mechanical ventilation settings in non-ECMO studies have been shown to have an effect on survival and may also have contributed to a treatment effect in ECMO trials. Protective lung ventilation strategies established for non-ECMO-supported respiratory failure patients may not be optimal for more severe forms of respiratory failure requiring ECMO support. The influence of positive end-expiratory pressure on the reduction of the left ventricular compliance may be a matter of concern for patients receiving ECMO support for cardiac failure. The objectives of this review were to describe potential mechanisms for lung injury during ECMO for respiratory or cardiac failure, to assess the possible benefits from the use of ultra-protective lung ventilation strategies and to review published guidelines and expert opinions available on mechanical ventilation-specific management of patients requiring ECMO, including mode and ventilator settings. Articles were identified through a detailed search of PubMed, Ovid, Cochrane databases and Google Scholar. Additional references were retrieved from the selected studies. Growing evidence suggests that mechanical ventilation settings are important in ECMO patients to minimize further lung damage and improve outcomes. An ultra-protective ventilation strategy may be optimal for mechanical ventilation during ECMO for respiratory failure. The effects of airway pressure on right and left ventricular afterload should be considered during venoarterial ECMO support of cardiac failure. Future studies are needed to better understand the potential impact of invasive mechanical ventilation modes and settings on outcomes. PMID:24447458

  6. Ventilation of Nonparalyzed Patients Under Anesthesia with Laryngeal Mask Airway, Comparison of Three Modes of Ventilation: Volume Controlled Ventilation, Pressure Controlled Ventilation, and Pressure Controlled Ventilation-volume Guarantee.

    PubMed

    Ghabach, Maroun Badwi; El Hajj, Elie M; El Dib, Rouba D; Rkaiby, Jeanette M; Matta, May S; Helou, May R

    2017-01-01

    Pressure controlled ventilation (PCV) is the preferable mode of ventilation of nonparalyzed patients undergoing anesthesia with laryngeal mask airway (LMA) as compared to volume controlled ventilation (VCV) and spontaneously breathing patient. In this study, we compared the PC-volume guarantee (PC-VG) mode of ventilation with VCV and PCV modes. A total of 30 patients, American Society of Anesthesiologists (ASA) physical status Classes I and II, scheduled for elective surgery under general anesthesia with a classic LMA were ventilated, subsequently, with the three modes of ventilation: VCV, PCV, and PC-VG for 10 min each mode. Tidal volume set for all patients was 8 ml/kg of ideal body weight. Parameters measured with modes of ventilation include peak inspiratory pressure (PIP), compliance, measured tidal volume, O2 saturation, end-tidal CO2, and presence of an oropharyngeal leak. The PIP was significantly higher with the application of VCV mode of ventilation than PCV and PC-VG modes. The compliance was significantly lower when using the mode of ventilation VCV than PCV and PC-VG. The PIP and the compliance were not statistically different between the PCV and PC-VG modes of ventilation. Ventilation of nonparalyzed patients with LMA under anesthesia with PC-VG is advantageous over VCV in reducing PIP and increasing lung compliance. No difference was noted between PCV and PC-VG in ASA Classes I or II under the adequate depth of anesthesia in patients with normal pulmonary function.

  7. Ventilator for internal combustion engine

    SciTech Connect

    Aoki, K.

    1986-04-08

    A ventilator is described for an internal combustion engine, consisting of: a housing; a diaphragm that divides the inside of the housing into a pressure chamber communicating with a crankcase and an atmospheric chamber communicating with the atmosphere; an outlet tube extending vertically in the pressure chamber and communicating with an intake manifold; a valve fixed to the diaphragm and acting to open or close an opening at an upper end of the outlet tube for controlling the quantity of blowby gas introduced into the outlet tube from the pressure chamber; an oil sump located at a lower end of the outlet tube and having a given capacity; a check valve mounted at the bottom of the oil sump to allow fluid to flow from the sump toward the pressure chamber; and an outlet port formed through the side wall of the outlet tube and protruding radially outwardly, the outlet tube being in communication with the intake manifold via the outlet port.

  8. The role of dead space ventilation in predicting outcome of successful weaning from mechanical ventilation.

    PubMed

    Mohr, A M; Rutherford, E J; Cairns, B A; Boysen, P G

    2001-11-01

    The exact mechanism by which tracheostomy results in clinical improvement in respiratory function and liberation from mechanical ventilation remains unknown. Physiologic dead space, which includes both normal and abnormal components of non-gas exchange tidal volume, is a clinical measure of the efficiency of ventilation. Theoretically, tracheostomy should reduce dead space ventilation and improve pulmonary mechanics, thereby facilitating weaning from mechanical ventilation. This study compares arterial blood gases (ABG), pulmonary mechanics, including minute ventilation (VE) and dead space ventilation (Vd/Vt) within 24 hours before and after tracheostomy in 45 patients admitted to a surgical intensive care unit. There was no difference noted in patients' ABG or VE. Pre- and posttracheostomy change in Vd/Vt was negligible (50.7 and 10 vs. 51.9 and 11; p = NS). On subgroup analysis, those patients that were weaned from mechanical ventilation with 72 hours of tracheostomy (T3) were compared with those patients weaned from mechanical ventilation 5 days or more after tracheostomy (T+5). Again, no difference was found in pulmonary mechanics or Vd/Vt pre- and posttracheostomy. There is minimal improvement in pulmonary mechanics after tracheostomy. The change in physiologic dead space posttracheostomy does not predict the outcome of weaning from mechanical ventilation. Tracheostomy does allow better pulmonary toilet, and easier initiation and removal of mechanical ventilation and control of the upper airway.

  9. [Comparison of volume preset and pressure preset ventilators during daytime nasal ventilation in chronic respiratory failure].

    PubMed

    Perrin, C; Wolter, P; Berthier, F; Tamisier, R; Jullien, V; Lemoigne, F; Blaive, B

    2001-02-01

    Both volume preset and pressure preset ventilators are available for domiciliary nasal ventilation. Owing to their technical characteristics, it has been suggested that impaired ventilatory mechanics might cause a drop in the tidal volume (Vt) delivered by pressure preset devices, thereby placing mechanical ventilation at risk of inefficacy. We have assessed two ventilator systems (one pressure preset and one volume preset) with regard to the tidal volume and end-tidal carbon dioxide tension (PetCO(2)) changes that may be achieved in a group of awake patients with stable chronic respiratory failure (CRF). Eleven patients with stable CRF were ventilated in the assist/control mode for two consecutive one-hour periods. One ventilator was tested each hour, in random order. The VIGIL'AIR(R) system was used to record Vt, Respiratory Rate (RR), and Inspiratory/Expiratory ratio (I/E). The deviation E (E=preset value - measured value) was calculated for each measurement. Changes in PetCO(2) and arterial oxygen saturation were determined respectively by a capnometer and a pulse oximeter. Comparison of the mean deviation of Vt calculated for the two ventilators revealed a difference in patients with chronic obstructive pulmonary disease (COPD). The deviation was greatest with the pressure preset ventilator (PPV), which gave mean measured values higher than the mean preset values. The same comparison failed to reveal any difference in restrictive CRF. Comparison of the volume preset and pressure preset ventilators for RR, I/E and PetCO(2) did not reveal any difference. Compared to the volume preset ventilator, the efficacy of PPV to ventilate is not affected by the restrictive or obstructive nature of CRF. Our results show that pressure-preset ventilator is an adequate alternative to the volume-preset device for daytime non invasive ventilation in chronic respiratory insufficiency.

  10. Oral mask ventilation is more effective than face mask ventilation after nasal surgery.

    PubMed

    Yazicioğlu, Dilek; Baran, Ilkay; Uzumcugil, Filiz; Ozturk, Ibrahim; Utebey, Gulten; Sayın, M Murat

    2016-06-01

    To evaluate and compare the face mask (FM) and oral mask (OM) ventilation techniques during anesthesia emergence regarding tidal volume, leak volume, and difficult mask ventilation (DMV) incidence. Prospective, randomized, crossover study. Operating room, training and research hospital. American Society of Anesthesiologists physical status I and II adult patients scheduled for nasal surgery. Patients in group FM-OM received FM ventilation first, followed by OM ventilation, and patients in group OM-FM received OM ventilation first, followed by FM ventilation, with spontaneous ventilation after deep extubation. The FM ventilation was applied with the 1-handed EC-clamp technique. The OM was placed only over the mouth, and the 1-handed EC-clamp technique was used again. A child's size FM was used for the OM ventilation technique, the mask was rotated, and the inferior part of the mask was placed toward the nose. The leak volume (MVleak), mean airway pressure (Pmean), and expired tidal volume (TVe) were assessed with each mask technique for 3 consecutive breaths. A mask ventilation grade ≥3 was considered DMV. DMV occurred more frequently during FM ventilation (75% with FM vs 8% with OM). In the FM-first sequence, the mean TVe was 249±61mL with the FM and 455±35mL with the OM (P=.0001), whereas in the OM-first sequence, it was 276±81mL with the FM and 409±37mL with the OM (P=.0001). Regardless of the order used, the OM technique significantly decreased the MVleak and increased the TVe when compared to the FM technique. During anesthesia emergence after nasal surgery the OM may offer an effective ventilation method as it decreases the incidence of DMV and the gas leak around the mask and provides higher tidal volume delivery compared with FM ventilation. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Infiltration as Ventilation: Weather-Induced Dilution

    SciTech Connect

    Sherman, Max H.; Turner, William J.N.; Walker, Iain S.

    2011-06-01

    The purpose of outdoor air ventilation is to dilute or remove indoor contaminants to which occupants are exposed. It can be provided by mechanical or natural means. In most homes, especially older homes, weather-driven infiltration provides the dominant fraction of the total ventilation. As we seek to provide good indoor air quality at minimum energy cost, it is important to neither over-ventilate nor under-ventilate. Thus, it becomes critically important to evaluate correctly the contribution infiltration makes to the total outdoor air ventilation rate. Because weather-driven infiltration is dependent on building air leakage and weather-induced pressure differences, a given amount of air leakage will provide different amounts of infiltration. Varying rates of infiltration will provide different levels of contaminant dilution and hence effective ventilation. This paper derives these interactions and then calculates the impact of weather-driven infiltration for different climates. A new “N-factor” is introduced to provide a convenient method for calculating the ventilation contribution of infiltration for over 1,000 locations across North America. The results of this work could be used in indoor air quality standards (specifically ASHRAE 62.2) to account for the contribution of weather-driven infiltration towards the dilution of indoor pollutants.

  12. Electrical Impedance Tomography During Mechanical Ventilation.

    PubMed

    Walsh, Brian K; Smallwood, Craig D

    2016-10-01

    Electrical impedance tomography (EIT) is a noninvasive, non-radiologic imaging modality that may be useful for the quantification of lung disorders and titration of mechanical ventilation. The principle of operation is based on changes in electrical conductivity that occur as a function of changes in lung volume during ventilation. EIT offers potentially important benefits over standard imaging modalities because the system is portable and non-radiologic and can be applied to patients for long periods of time. Rather than providing a technical dissection of the methods utilized to gather, compile, reconstruct, and display EIT images, the present article seeks to provide an overview of the clinical application of this technology as it relates to monitoring mechanical ventilation and providing decision support at the bedside. EIT has been shown to be useful in the detection of pneumothoraces, quantification of pulmonary edema and comparison of distribution of ventilation between different modes of ventilation and may offer superior individual titration of PEEP and other ventilator parameters compared with existing approaches. Although application of EIT is still primarily done within a research context, it may prove to be a useful bedside tool in the future. However, head-to-head comparisons with existing methods of mechanical ventilation titration in humans need to be conducted before its application in general ICUs can be recommended. Copyright © 2016 by Daedalus Enterprises.

  13. Ventilation Inception and Washout, Scaling, and Effects on Hydrodynamic Performance of a Surface Piercing Strut

    NASA Astrophysics Data System (ADS)

    Harwood, Casey; Young, Yin Lu; Ceccio, Steven

    2014-11-01

    High-lift devices that operate at or near a fluid free surface (such as surface-piercing or shallowly-submerged propellers and hydrofoils) are prone to a multiphase flow phenomenon called ventilation, wherein non-condensable gas is entrained in the low-pressure flow, forming a cavity around the body and dramatically altering the global hydrodynamic forces. Experiments are being conducted at the University of Michigan's towing tank using a canonical surface-piercing strut to investigate atmospheric ventilation. The goals of the work are (i) to gain an understanding of the dominant physics in fully wetted, partially ventilated, and fully ventilated flow regimes, (ii) to quantify the effects of governing dimensionless parameters on the transition between flow regimes, and (iii) to develop scaling relations for the transition between flow regimes. Using theoretical arguments and flow visualization techniques, new criteria are developed for classifying flow regimes and transition mechanisms. Unsteady transition mechanisms are described and mapped as functions of the governing non-dimensional parameters. A theoretical scaling relationship is developed for ventilation washout, which is shown to adequately capture the experimentally-observed washout boundary. This material is based upon work supported by the National Science Foundation Graduate Student Research Fellowship under Grant No. DGE 1256260. Support also comes from the Naval Engineering Education Center (Award No. N65540-10-C-003).

  14. Dangerous Pressurization and Inappropriate Alarms during Water Occlusion of the Expiratory Circuit of Commonly Used Infant Ventilators

    PubMed Central

    Perdomo, Aldo

    2016-01-01

    Background Non-invasive continuous positive airways pressure is commonly a primary respiratory therapy delivered via multi-purpose ventilators in premature newborns. Expiratory limb occlusion due to water accumulation or ‘rainout’ from gas humidification is a frequent issue. A case of expiratory limb occlusion due to rainout causing unexpected and excessive repetitive airway pressurisation in a Draeger VN500 prompted a systematic bench test examination of currently available ventilators. Objective To assess neonatal ventilator response to partial or complete expiratory limb occlusion when set to non-invasive continuous positive airway pressure mode. Design Seven commercially available neonatal ventilators connected to a test lung using a standard infant humidifier circuit with partial and/or complete expiratory limb occlusion were examined in a bench test study. Each ventilator was set to deliver 6 cmH2O in non-invasive mode and respiratory mechanics data for 75%, 80% and 100% occlusion were collected. Results Several ventilators responded inappropriately with complete occlusion by cyclical pressurisation/depressurisation to peak pressures of between 19·4 and 64·6 cm H2O at rates varying between 2 to 77 inflations per minute. Tidal volumes varied between 10·1 and 24·3mL. Alarm responses varied from ‘specific’ (tube occluded) to ‘ambiguous’ (Safety valve open). Carefusion Avea responded by continuing to provide the set distending pressure and displaying an appropriate alarm message. Draeger Babylog 8000 did not alarm with partial occlusions and incorrectly displayed airways pressure at 6·1cmH2O compared to the measured values of 13cmH2O. Conclusions This study found a potential for significant adverse ventilator response due to complete or near complete expiratory limb occlusion in CPAP mode. PMID:27116224

  15. Variation in Definition of Prolonged Mechanical Ventilation.

    PubMed

    Rose, Louise; McGinlay, Michael; Amin, Reshma; Burns, Karen Ea; Connolly, Bronwen; Hart, Nicholas; Jouvet, Philippe; Katz, Sherri; Leasa, David; Mawdsley, Cathy; McAuley, Danny F; Schultz, Marcus J; Blackwood, Bronagh

    2017-10-01

    Consistency of definitional criteria for terminology applied to describe subject cohorts receiving mechanical ventilation within ICU and post-acute care settings is important for understanding prevalence, risk stratification, effectiveness of interventions, and projections for resource allocation. Our objective was to quantify the application and definition of terms for prolonged mechanical ventilation. We conducted a scoping review of studies (all designs except single-case study) reporting a study population (adult and pediatric) using the term prolonged mechanical ventilation or a synonym. We screened 5,331 references, reviewed 539 full-text references, and excluded 120. Of the 419 studies (representing 38 countries) meeting inclusion criteria, 297 (71%) reported data on a heterogeneous subject cohort, and 66 (16%) included surgical subjects only (46 of those 66, 70% cardiac surgery). Other studies described COPD (16, 4%), trauma (22, 5%), neuromuscular (17, 4%), and sepsis (1, 0.2%) cohorts. A total of 741 terms were used to refer to the 419 study cohorts. The most common terms were: prolonged mechanical ventilation (253, 60%), admission to specialized unit (107, 26%), and long-term mechanical ventilation (79, 19%). Some authors (282, 67%) defined their cohorts based on duration of mechanical ventilation, with 154 studies (55%) using this as the sole criterion. We identified 37 different durations of ventilation ranging from 5 h to 1 y, with > 21 d being the most common (28 of 282, 7%). For studies describing a surgical cohort, minimum ventilation duration required for inclusion was ≥ 24 h for 20 of 66 studies (30%). More than half of all studies (237, 57%) did not provide a reason/rationale for definitional criteria used, with only 28 studies (7%) referring to a consensus definition. We conclude that substantial variation exists in the terminology and definitional criteria for cohorts of subjects receiving prolonged mechanical ventilation. Standardization of

  16. [Heat transfer analysis of liquid cooling garment used for extravehicular activity].

    PubMed

    Qiu, Y F; Yuan, X G; Mei, Z G; Jia, S G; Ouyang, H; Ren, Z S

    2001-10-01

    Brief description was given about the construction and function of the LCG (liquid cooling garment) used for EVA (extravehicular activity). The heat convection was analyzed between ventilating gas and LCG, the heat and mass transfer process was analyzed too, then a heat and mass transfer mathematical model of LCG was developed. Thermal physiological experimental study with human body wearing LVCG (liquid cooling and ventilation garment) used for EVA was carried out to verify this mathematical model. This study provided a basis for the design of liquid-cooling and ventilation system for the space suit.

  17. Special Considerations in Neonatal Mechanical Ventilation.

    PubMed

    Dalgleish, Stacey; Kostecky, Linda; Charania, Irina

    2016-12-01

    Care of infants supported with mechanical ventilation is complex, time intensive, and requires constant vigilance by an expertly prepared health care team. Current evidence must guide nursing practice regarding ventilated neonates. This article highlights the importance of common language to establish a shared mental model and enhance clear communication among the interprofessional team. Knowledge regarding the underpinnings of an open lung strategy and the interplay between the pathophysiology and individual infant's response to a specific ventilator strategy is most likely to result in a positive clinical outcome.

  18. How to choose an anesthesia ventilator?

    PubMed

    Coisel, Y; Millot, A; Carr, J; Castagnoli, A; Pouzeratte, Y; Verzilli, D; Futier, E; Jaber, S

    2014-01-01

    During the past few years, many manufacturers have developed a new generation anesthesia ventilators or anesthesia workstations with innovative technology and introduced so-called new ventilatory modes in the operating room. The aim of this article is to briefly explain how an anesthesia ventilator works, to describe the main differences between the technologies used, to describe the main criteria for evaluating technical and pneumatic performances and to list key elements not to be forgotten during the process of acquiring an anesthesia ventilator. Copyright © 2014. Published by Elsevier SAS.

  19. Bronchoscopy during noninvasive ventilation: indications and technique.

    PubMed

    Murgu, Septimiu D; Pecson, Jocelyn; Colt, Henri G

    2010-05-01

    Diagnostic or therapeutic flexible bronchoscopy is often necessary in severely ill patients. These patients often have comorbidities that increase the risk of bronchoscopy-related complications. Noninvasive ventilation might decrease the risk of these complications in patients with severe refractory hypoxemia, postoperative respiratory distress, or severe emphysema, and in pediatric patients. Noninvasive ventilation may prevent hypoventilation in patients with obstructive sleep apnea and obesity hypoventilation syndrome who require bronchoscopy, and may assist in the bronchoscopic evaluation of patients with expiratory central-airway collapse. We describe the indications, contraindications, and technique of flexible bronchoscopy during noninvasive ventilation.

  20. [Classification and terminology of artificial lung ventilation].

    PubMed

    Gal'perin, Iu S

    2005-01-01

    The author considers the main features of a prepared edition of the international standard ISO 4135:2001 "Equipment for anesthesia and artificial ventilation. Glossary" as the state standard of Russia. He shows methods for classification of the modes of ventilation support. A classification scheme of its procedures is proposed, by giving necessary notes. The abbreviations of these procedures are given in the Russian and English languages. The shorthand notations of airways gas pressure in the characteristic points of a respiratory cycle are clarified in detail and on this basis the procedures for limiting inspiration pressure during controlled artificial ventilation.

  1. Ventilatory management of one-lung ventilation.

    PubMed

    Della Rocca, G; Coccia, C

    2011-05-01

    Hypoxemia is considered to be the most important challenge during one-lung ventilation (OLV). Recent studies, however, have shown that one-lung ventilation can involve some lung damage and can therefore be per se a cause of hypoxemia. OLV can be associated to an injury: but the techniques used to improve oxygenation may also damage the lung. A new ventilator approach should be used and applied with regards to what is so far known in terms of "lung protection" also during OLV.

  2. Do new anesthesia ventilators deliver small tidal volumes accurately during volume-controlled ventilation?

    PubMed

    Bachiller, Patricia R; McDonough, Joseph M; Feldman, Jeffrey M

    2008-05-01

    During mechanical ventilation of infants and neonates, small changes in tidal volume may lead to hypo- or hyperventilation, barotrauma, or volutrauma. Partly because breathing circuit compliance and fresh gas flow affect tidal volume delivery by traditional anesthesia ventilators in volume-controlled ventilation (VCV) mode, pressure-controlled ventilation (PCV) using a circle breathing system has become a common approach to minimizing the risk of mechanical ventilation for small patients, although delivered tidal volume is not assured during PCV. A new generation of anesthesia machine ventilators addresses the problems of VCV by adjusting for fresh gas flow and for the compliance of the breathing circuit. In this study, we evaluated the accuracy of new anesthesia ventilators to deliver small tidal volumes. Four anesthesia ventilator systems were evaluated to determine the accuracy of volume delivery to the airway during VCV at tidal volume settings of 100, 200, and 500 mL under different conditions of breathing circuit compliance (fully extended and fully contracted circuits) and lung compliance. A mechanical test lung (adult and infant) was used to simulate lung compliances ranging from 0.0025 to 0.03 L/cm H(2)O. Volumes and pressures were measured using a calibrated screen pneumotachograph and custom software. We tested the Smartvent 7900, Avance, and Aisys anesthesia ventilator systems (GE Healthcare, Madison, WI) and the Apollo anesthesia ventilator (Draeger Medical, Telford, PA). The Smartvent 7900 and Avance ventilators use inspiratory flow sensors to control the volume delivered, whereas the Aisys and Apollo ventilators compensate for the compliance of the circuit. We found that the anesthesia ventilators that use compliance compensation (Aisys and Apollo) accurately delivered both large and small tidal volumes to the airway of the test lung under conditions of normal and low lung compliance during VCV (ranging from 95.5% to 106.2% of the set tidal volume

  3. Wettability of partially suspended graphene

    DOE PAGES

    Ondarçuhu, Thierry; Thomas, Vincent; Nuñez, Marc; ...

    2016-04-13

    Dependence on the wettability of graphene on the nature of the underlying substrate remains only partially understood. We systematically investigate the role of liquid-substrate interactions on the wettability of graphene by varying the area fraction of suspended graphene from 0 to 95% by means of nanotextured substrates. We find that completely suspended graphene exhibits the highest water contact angle (85° ± 5°) compared to partially suspended or supported graphene, regardless of the hydrophobicity (hydrophilicity) of the substrate. Moreover, 80% of the long-range water-substrate interactions are screened by the graphene monolayer, the wettability of which is primarily determined by short-range graphene-liquidmore » interactions. By its well-defined chemical and geometrical properties, supported graphene therefore provides a model system to elucidate the relative contribution of short and long range interactions to the macroscopic contact angle.« less

  4. Application of CO2 waveform in the alveolar recruitment maneuvers of hypoxemic patients during one-lung ventilation

    PubMed Central

    Dong, Chunshan; Yu, Junma; Liu, Qi; Wu, Chao; Lu, Yao

    2016-01-01

    Abstract Deterioration of gas exchange during one-lung ventilation (OLV) is caused by both total collapse of the nondependent lung and partial collapse of the dependent lung. Alveolar recruitment maneuver improves lung function during general anesthesia. The objective of this study was to investigate whether there is an indirect relationship between the changes of CO2 expirogram and the selective lung recruitment. To further improve the oxygenation and gas exchange, we compare adjust setting of ventilated parameters based on CO2 expirogram and a preset setting of ventilated parameters during OLV in patients undergoing right-side thoracic surgery. Thirty patients met the requirements criteria that were studied at 3 time points: during two-lung ventilation (TLV), during OLV with preset ventilation parameters (OLV-PP), and during OLV with adjustable ventilation parameters (OLV-AP) that are in accordance with CO2 expirogram. Adjustable ventilation parameters such as tidal volume (VT), respiratory rate (RR), positive end-expiratory pressure (PEEP), and the ratio of inspiratory to expiratory were adjusted by utilizing the phase III slopes of CO2 expirogram, which together with the relationship between the changes of CO2 expirogram and the selective lung recruitment. During OLV, the phase III slopes of CO2 expirogram in patients with pulse oxymetry (SpO2) decreased less than 93% after the OLV-PP, and were absolutely different from that during TLV. After OLV-AP, the phase III slopes of CO2 expirogram and SpO2 were similar to those during TLV. During OLV, however, parameters of ventilation setting in both OLV-PP and OLV-AP are obviously different. This study indicates that alveolar recruitment by utilizing CO2 expirogram probably improves SpO2 level during one-lung ventilation. PMID:27310989

  5. Application of CO2 waveform in the alveolar recruitment maneuvers of hypoxemic patients during one-lung ventilation.

    PubMed

    Dong, Chunshan; Yu, Junma; Liu, Qi; Wu, Chao; Lu, Yao

    2016-06-01

    Deterioration of gas exchange during one-lung ventilation (OLV) is caused by both total collapse of the nondependent lung and partial collapse of the dependent lung. Alveolar recruitment maneuver improves lung function during general anesthesia. The objective of this study was to investigate whether there is an indirect relationship between the changes of CO2 expirogram and the selective lung recruitment. To further improve the oxygenation and gas exchange, we compare adjust setting of ventilated parameters based on CO2 expirogram and a preset setting of ventilated parameters during OLV in patients undergoing right-side thoracic surgery.Thirty patients met the requirements criteria that were studied at 3 time points: during two-lung ventilation (TLV), during OLV with preset ventilation parameters (OLV-PP), and during OLV with adjustable ventilation parameters (OLV-AP) that are in accordance with CO2 expirogram. Adjustable ventilation parameters such as tidal volume (VT), respiratory rate (RR), positive end-expiratory pressure (PEEP), and the ratio of inspiratory to expiratory were adjusted by utilizing the phase III slopes of CO2 expirogram, which together with the relationship between the changes of CO2 expirogram and the selective lung recruitment.During OLV, the phase III slopes of CO2 expirogram in patients with pulse oxymetry (SpO2) decreased less than 93% after the OLV-PP, and were absolutely different from that during TLV. After OLV-AP, the phase III slopes of CO2 expirogram and SpO2 were similar to those during TLV. During OLV, however, parameters of ventilation setting in both OLV-PP and OLV-AP are obviously different.This study indicates that alveolar recruitment by utilizing CO2 expirogram probably improves SpO2 level during one-lung ventilation.

  6. 33 CFR 183.620 - Natural ventilation system.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Natural ventilation system. 183... (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Ventilation § 183.620 Natural ventilation system. (a) Except for compartments open to the atmosphere, a natural ventilation system that meets the...

  7. 33 CFR 183.620 - Natural ventilation system.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Natural ventilation system. 183... (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Ventilation § 183.620 Natural ventilation system. (a) Except for compartments open to the atmosphere, a natural ventilation system that meets the...

  8. 46 CFR 72.15-15 - Ventilation for closed spaces.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 3 2012-10-01 2012-10-01 false Ventilation for closed spaces. 72.15-15 Section 72.15-15... ARRANGEMENT Ventilation § 72.15-15 Ventilation for closed spaces. (a) All enclosed spaces within the vessel... spaces and for closing all doorways, ventilators and annular spaces around funnels and other openings to...

  9. 46 CFR 72.15-15 - Ventilation for closed spaces.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 3 2014-10-01 2014-10-01 false Ventilation for closed spaces. 72.15-15 Section 72.15-15... ARRANGEMENT Ventilation § 72.15-15 Ventilation for closed spaces. (a) All enclosed spaces within the vessel... spaces and for closing all doorways, ventilators and annular spaces around funnels and other openings to...

  10. 46 CFR 111.103-3 - Machinery space ventilation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Machinery space ventilation. 111.103-3 Section 111.103-3...-GENERAL REQUIREMENTS Remote Stopping Systems § 111.103-3 Machinery space ventilation. (a) Each machinery space ventilation system must have two controls to stop the ventilation, one of which may be the supply...

  11. 46 CFR 92.15-10 - Ventilation for closed spaces.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Ventilation for closed spaces. 92.15-10 Section 92.15-10... CONSTRUCTION AND ARRANGEMENT Ventilation § 92.15-10 Ventilation for closed spaces. (a) Except as noted in paragraph (c) of this section, all enclosed spaces within the vessel shall be properly vented or ventilated...

  12. 46 CFR 108.181 - Ventilation for enclosed spaces.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Ventilation for enclosed spaces. 108.181 Section 108.181... AND EQUIPMENT Construction and Arrangement Ventilation § 108.181 Ventilation for enclosed spaces. (a) Each enclosed space must be vented or ventilated. (b) There must be a means to close each vent or...

  13. 46 CFR 92.15-10 - Ventilation for closed spaces.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Ventilation for closed spaces. 92.15-10 Section 92.15-10... CONSTRUCTION AND ARRANGEMENT Ventilation § 92.15-10 Ventilation for closed spaces. (a) Except as noted in paragraph (c) of this section, all enclosed spaces within the vessel shall be properly vented or ventilated...

  14. 46 CFR 92.15-10 - Ventilation for closed spaces.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Ventilation for closed spaces. 92.15-10 Section 92.15-10... CONSTRUCTION AND ARRANGEMENT Ventilation § 92.15-10 Ventilation for closed spaces. (a) Except as noted in paragraph (c) of this section, all enclosed spaces within the vessel shall be properly vented or ventilated...

  15. 46 CFR 111.103-3 - Machinery space ventilation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Machinery space ventilation. 111.103-3 Section 111.103-3...-GENERAL REQUIREMENTS Remote Stopping Systems § 111.103-3 Machinery space ventilation. (a) Each machinery space ventilation system must have two controls to stop the ventilation, one of which may be the supply...

  16. 46 CFR 108.181 - Ventilation for enclosed spaces.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Ventilation for enclosed spaces. 108.181 Section 108.181... AND EQUIPMENT Construction and Arrangement Ventilation § 108.181 Ventilation for enclosed spaces. (a) Each enclosed space must be vented or ventilated. (b) There must be a means to close each vent or...

  17. 46 CFR 111.103-3 - Machinery space ventilation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Machinery space ventilation. 111.103-3 Section 111.103-3...-GENERAL REQUIREMENTS Remote Stopping Systems § 111.103-3 Machinery space ventilation. (a) Each machinery space ventilation system must have two controls to stop the ventilation, one of which may be the supply...

  18. 46 CFR 72.15-15 - Ventilation for closed spaces.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 3 2013-10-01 2013-10-01 false Ventilation for closed spaces. 72.15-15 Section 72.15-15... ARRANGEMENT Ventilation § 72.15-15 Ventilation for closed spaces. (a) All enclosed spaces within the vessel... spaces and for closing all doorways, ventilators and annular spaces around funnels and other openings to...

  19. 46 CFR 108.181 - Ventilation for enclosed spaces.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Ventilation for enclosed spaces. 108.181 Section 108.181... AND EQUIPMENT Construction and Arrangement Ventilation § 108.181 Ventilation for enclosed spaces. (a) Each enclosed space must be vented or ventilated. (b) There must be a means to close each vent or...

  20. 30 CFR 77.1911 - Ventilation of slopes and shafts.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Ventilation of slopes and shafts. 77.1911... COAL MINES Slope and Shaft Sinking § 77.1911 Ventilation of slopes and shafts. (a) All slopes and shafts shall be ventilated by mechanical ventilation equipment during development. Such equipment...