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Sample records for stable ventilation systems

  1. Active Fault Tolerant Control of Livestock Stable Ventilation System

    DEFF Research Database (Denmark)

    Gholami, Mehdi

    2011-01-01

    degraded performance even in the faulty case. In this thesis, we have designed such controllers for climate control systems for livestock buildings in three steps: Deriving a model for the climate control system of a pig-stable. Designing a active fault diagnosis (AFD) algorithm for different kinds......). In the FTC part of the thesis, first a passive fault tolerant controller (PFTC) based on state feed-back is proposed for discretetime PWA systems. only actuator faults are considered. By dissipativity theory and H1 analysis, the problem is cast as a set of linear matrix inequalities (LMIs). In the next...... contribution, the problem of reconfigurability of PWA systems is evaluated. A system subject to a fault is considered as reconfigurable if it can be stabilized by a state feedback controller and the optimal cost of the performance of the systems is admissible. In the previous methods the input constraints...

  2. Embedded Controller Design for Pig Stable Ventilation Systems

    DEFF Research Database (Denmark)

    Jessen, Jan Jacob

    This thesis focuses on zone based climate control in pig stables and how to implement climate controllers in a new range of products. The presented controllers are based on simple models of climate dynamics and simple models of actuators. The implementation uses graphical point and click features...... source code for the actual target platform, on which the climate controller is expected to execute. The third paper also deals with the development cycle of controllers, showing how to build a graphical user interface for point and click modelling of zone based climate dynamics. The next two papers...

  3. Ventilation and Heat Recovering System

    Directory of Open Access Journals (Sweden)

    Olga Bancea

    2007-01-01

    Full Text Available Some aspects concerning the heat reducing for ventilation, achieved by using heat recovering components and a combined heating--ventilating system, assuring both comfort and human health are presented. The floor imbedded systems together with air outlets elements could fulfill all the aesthetically desires, as well as comfort and they are ideal for family houses.

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

    Energy Technology Data Exchange (ETDEWEB)

    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. Preoperational test report, vent building ventilation system

    Energy Technology Data Exchange (ETDEWEB)

    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.

  6. Ventilation systems for high halls

    Energy Technology Data Exchange (ETDEWEB)

    Sodec, F.; Veldboer, W.

    1982-02-01

    A ventilation system for high halls is described which meets the demands of steady air flow in spite of inverse thermal currents, intensive ventilation of working areas during heating and cooling and ventilation free of draught. The main element of the ventilation system is the air outlet in the ceiling, with variable beam direction. The horizontal, rotated beams are superimposed by a vertical beam whose strength may be varied. This way, the beam direction can be adapted to the thermal load of the hall and the height of blowout. The blowout angle is large for heating and small for cooling. Studies have shown that halls are ventilated thoroughly and free of draught by this system. The variable, rotary outlet presented in the article is best suited for heights of 4.00 to 12.00 m. The outlet, with a rated diameter of 400 mm, has been in use for two years now in fields as varied as diecasting works, halls at fairs, sports halls, etc. The air volume flow rate is 1000 to 3000 m/sup 3//h per outlet. A bigger version is now being developed; it will have a rated diameter of 710 mm and an air volume flow rate of 3000 to 9000 m/sup 3//h.

  7. 14 CFR 252.9 - Ventilation systems.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Ventilation systems. 252.9 Section 252.9... REGULATIONS SMOKING ABOARD AIRCRAFT § 252.9 Ventilation systems. Air carriers shall prohibit smoking whenever the ventilation system is not fully functioning. Fully functioning for this purpose means operating so...

  8. Preoperational test report, primary ventilation system

    Energy Technology Data Exchange (ETDEWEB)

    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.

  9. Preoperational test report, primary ventilation condensate system

    Energy Technology Data Exchange (ETDEWEB)

    Clifton, F.T.

    1997-01-29

    Preoperational test report for Primary Ventilation Condensate System, Project W-030. Project W-030 provides a ventilation upgrade for the four Aging Waste Facility tanks. The system provides a collection point for condensate generated by the W-030 primary vent offgas cooling system serving tanks AYIOI, AY102, AZIOI, AZI02. The system is located inside a shielded ventilation equipment cell and consists of a condensate seal pot, sampling features, a drain line to existing Catch Tank 241-AZ-151, and a cell sump jet pump. The tests verify correct system operation and correct indications displayed by the central Monitor and Control System.

  10. Hybrid ventilation systems and high performance buildings

    Energy Technology Data Exchange (ETDEWEB)

    Utzinger, D.M. [Wisconsin Univ., Milwaukee, WI (United States). School of Architecture and Urban Planning

    2009-07-01

    This paper described hybrid ventilation design strategies and their impact on 3 high performance buildings located in southern Wisconsin. The Hybrid ventilation systems combined occupant controlled natural ventilation with mechanical ventilation systems. Natural ventilation was shown to provide adequate ventilation when appropriately designed. Proper control integration of natural ventilation into hybrid systems was shown to reduce energy consumption in high performance buildings. This paper also described the lessons learned from the 3 buildings. The author served as energy consultant on all three projects and had the responsibility of designing and integrating the natural ventilation systems into the HVAC control strategy. A post occupancy evaluation of building energy performance has provided learning material for architecture students. The 3 buildings included the Schlitz Audubon Nature Center completed in 2003; the Urban Ecology Center completed in 2004; and the Aldo Leopold Legacy Center completed in 2007. This paper included the size, measured energy utilization intensity and percentage of energy supplied by renewable solar power and bio-fuels on site for each building. 6 refs., 2 tabs., 6 figs.

  11. Optimized damper control of pressure and airflow in ventilation systems

    DEFF Research Database (Denmark)

    Koulani, Chrysanthi Sofia; Hviid, Christian Anker; Terkildsen, Søren

    2014-01-01

    Conventional control strategies in variable air volume (VAV) ventilation systems do not take fully into advantage the potential energy savings since the system operation is based on maintaining a constant static pressure (CSP) set point in the main duct irrespective of the actual pressure demand...... by using the Simulink programming tool which is addon software to MATLAB mathematical programming language. A model of a VAV ventilation system was created in Simulink based on the International Building Physics Toolbox (IBPT); the IBPT thermal zone was remodelled in order to calculate dynamically...... the airflow demand according to the zone air temperature. The performance of the Simulink model was evaluated based on the experimental setup of the ventilation system. The SPR control method established stable system operation and was proven efficient to maintain comfortable space conditions while reducing...

  12. Modelling and Simulation of Volume Controlled Mechanical Ventilation System

    Directory of Open Access Journals (Sweden)

    Yan Shi

    2014-01-01

    Full Text Available Volume controlled mechanical ventilation system is a typical time-delay system, which is applied to ventilate patients who cannot breathe adequately on their own. To illustrate the influences of key parameters of the ventilator on the dynamics of the ventilated respiratory system, this paper firstly derived a new mathematical model of the ventilation system; secondly, simulation and experimental results are compared to verify the mathematical model; lastly, the influences of key parameters of ventilator on the dynamics of the ventilated respiratory system are carried out. This study can be helpful in the VCV ventilation treatment and respiratory diagnostics.

  13. Evaluating Ventilation Systems for Existing Homes

    Energy Technology Data Exchange (ETDEWEB)

    Aldrich, Robb [Consortium for Advanced Residential Buildings (CARB), Norwalk, CT (United States); Arena, Lois [Consortium for Advanced Residential Buildings (CARB), Norwalk, CT (United States)

    2013-02-01

    In an effort to improve housing options near Las Vegas, Nevada, the Clark County Community Resources Division (CCCRD) performs substantial renovations to foreclosed homes. After dramatic energy, aesthetic, and health and safety improvements are made, homes are rented or sold to qualified residents. This report describes the evaluation and selection of ventilation systems for these homes, including key considerations when selecting an ideal system. The report then describes CCCRD’s decision process with respect to ventilation.

  14. 46 CFR 154.1200 - Mechanical ventilation system: General.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Mechanical ventilation system: General. 154.1200 Section... Equipment Cargo Area: Mechanical Ventilation System § 154.1200 Mechanical ventilation system: General. (a... cargo handling equipment must have a fixed, exhaust-type mechanical ventilation system. (b) The...

  15. 46 CFR 154.1205 - Mechanical ventilation system: Standards.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Mechanical ventilation system: Standards. 154.1205... Equipment Cargo Area: Mechanical Ventilation System § 154.1205 Mechanical ventilation system: Standards. (a) Each exhaust type mechanical ventilation system required under § 154.1200 (a) must have ducts for...

  16. Intelligent decision support systems for mechanical ventilation.

    Science.gov (United States)

    Tehrani, Fleur T; Roum, James H

    2008-11-01

    An overview of different methodologies used in various intelligent decision support systems (IDSSs) for mechanical ventilation is provided. The applications of the techniques are compared in view of today's intensive care unit (ICU) requirements. Information available in the literature is utilized to provide a methodological review of different systems. Comparisons are made of different systems developed for specific ventilation modes as well as those intended for use in wider applications. The inputs and the optimized parameters of different systems are discussed and rule-based systems are compared to model-based techniques. The knowledge-based systems used for closed-loop control of weaning from mechanical ventilation are also described. Finally, in view of increasing trend towards automation of mechanical ventilation, the potential utility of intelligent advisory systems for this purpose is discussed. IDSSs for mechanical ventilation can be quite helpful to clinicians in today's ICU settings. To be useful, such systems should be designed to be effective, safe, and easy to use at patient's bedside. In particular, these systems must be capable of noise removal, artifact detection and effective validation of data. Systems that can also be adapted for closed-loop control/weaning of patients at the discretion of the clinician, may have a higher potential for use in the future.

  17. 33 CFR 183.620 - Natural ventilation system.

    Science.gov (United States)

    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...

  18. Preoperational test report, recirculation ventilation systems

    Energy Technology Data Exchange (ETDEWEB)

    Clifton, F.T.

    1997-11-11

    This represents a preoperational test report for Recirculation Ventilation Systems, Project W-030. Project W-030 provides a ventilation upgrade for the four Aging Waste Facility tanks. The system provides vapor space cooling of tanks AY1O1, AY102, AZ1O1, AZ102 and supports the ability to exhaust air from each tank. Each system consists of a valved piping loop, a fan, condenser, and moisture separator; equipment is located inside each respective tank farm in its own hardened building. The tests verify correct system operation and correct indications displayed by the central Monitor and Control System.

  19. Multiple factors influencing OR ventilation system effectiveness

    Directory of Open Access Journals (Sweden)

    Buhl Sebastian

    2016-09-01

    Full Text Available The issue of surgical site infections has become more critical during the last years. The number of airborne microbes depends on the number released by the staff in the room or supplied from neighbouring rooms. In order to minimize the risk of nosocomial infections during surgical procedures technical developments like ventilation systems were introduced in the operating room (OR. In this study several factors like clothing and types of ventilation systems have been investigated and their impact on the effectiveness for reducing microbial burden in the OR has been assessed. In case of OR-gowns we found a benefit for a disposable Swedish clothing concept regarding microbiological contamination in comparison with the German standard multiuse clothing. Moreover our study shows that there is comparable effectiveness of a fairly novel temperature controlled airflow ventilation system (TAF compared to standard low turbulent uni-directional airflow (TAV.

  20. Advanced design of local ventilation systems

    Energy Technology Data Exchange (ETDEWEB)

    Kulmala, I. [VTT Manufacturing Technology, Espoo (Finland). Safety Technology

    1997-12-31

    Local ventilation is widely used in industry for controlling airborne contaminants. However, the present design practices of local ventilation systems are mainly based on empirical equations and do not take quantitatively into account the various factors affecting the performance of these systems. The aim of this study was to determine the applicability and limitations of more advanced fluid mechanical methods to the design and development of local ventilation systems. The most important factors affecting the performance of local ventilation systems were determined and their effect was studied in a systematic manner. The numerical calculations were made with the FLUENT computer code and they were verified by laboratory experiments, previous measurements or analytical solutions. The results proved that the numerical calculations can provide a realistic simulation of exhaust openings, effects of ambient air flows and wake regions. The experiences with the low-velocity local supply air showed that these systems can also be modelled fairly well. The results were used to improve the efficiency and thermal comfort of a local ventilation unit and to increase the effective control range of exhaust hoods. In the simulation of the interaction of a hot buoyant source and local exhaust, the predicted capture efficiencies were clearly higher than those observed experimentally. The deviations between measurements and non-isothermal flow calculations may have partly been caused by the inability to achieve grid independent solutions. CFD simulations is an advanced and flexible tool for designing and developing local ventilation. The simulations can provide insight into the time-averaged flow field which may assist us in understanding the observed phenomena and to explain experimental results. However, for successful calculations the applicability and limitations of the models must be known. (orig.) 78 refs.

  1. Energy diagnosis of industrial ventilation systems; Diagnostic energetique des installations de ventilation industrielle

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2003-11-01

    Industrial ventilation systems are numerous and represent an important source of potential energy saving. This book shades light on the principles of ventilation systems used in companies and on the investigation methods to be implemented for an energy diagnosis of these systems. It proposes some solutions for the improvement of existing ventilation systems and some suggestions for the formulation and presentation of recommendations. (J.S.)

  2. Dimensionless study on dynamics of pressure controlled mechanical ventilation system

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Yan; Niu, Jinglong; Cai, Maolin; Xu, Weiqing [Beihang University, Beijing (Korea, Republic of)

    2015-02-15

    Dynamics of mechanical ventilation system can be referred in pulmonary diagnostics and treatments. In this paper, to conveniently grasp the essential characteristics of mechanical ventilation system, a dimensionless model of mechanical ventilation system is presented. For the validation of the mathematical model, a prototype mechanical ventilation system of a lung simulator is proposed. Through the simulation and experimental studies on the dimensionless dynamics of the mechanical ventilation system, firstly, the mathematical model is proved to be authentic and reliable. Secondly, the dimensionless dynamics of the mechanical ventilation system are obtained. Last, the influences of key parameters on the dimensionless dynamics of the mechanical ventilation system are illustrated. The study provides a novel method to study the dynamic of mechanical ventilation system, which can be referred in the respiratory diagnostics and treatment.

  3. Design guidelines for natural ventilation systems in tertiary sector buildings

    OpenAIRE

    Van Moeseke, Geoffrey; Bruyère, Isabelle; De Herde, André; CISBAT 2005: Renewables in a changing climate

    2005-01-01

    Parameters determining efficiency of natural ventilation systems are numerous. The most important are architecture and system design. This article get onto both but focuses on system design. Through dynamic simulations it shows that natural ventilation management has a large impact on energy saving but most of all on thermal comfort. Natural ventilation techniques are also weighted against hybrid solutions and high efficiency mechanical cooling solutions. Natural ventilation techniques show t...

  4. Nocturnal noninvasive positive pressure ventilation in stable COPD : A systematic review and individual patient data meta-analysis

    NARCIS (Netherlands)

    Struik, F. M.; Lacasse, Y.; Goldstein, R. S.; Kerstjens, H. A. M.; Wijkstra, P. J.

    Introduction: The effects of nocturnal noninvasive positive pressure ventilation (NIPPV) in patients with stable chronic obstructive pulmonary disease (COPD) remain controversial. Methods: The Cochrane Airways group Register of Trials, MEDLINE, EMBASE and CINAHL were searched up to August 2012.

  5. Modeling and Control of Livestock Ventilation Systems and Indoor Environments

    DEFF Research Database (Denmark)

    Wu, Zhuang; Heiselberg, Per; Stoustrup, Jakob

    2005-01-01

    The hybrid ventilation systems have been widely used for livestock barns to provide optimum indoor climate by controlling the ventilation rate and air flow distribution within the ventilated building structure. The purpose of this paper is to develop models for livestock ventilation systems and i...... constraints and random disturbances is designed through system linearization. The well designed control systems are able to determine the demand ventilation rate and airflow pattern, improve and optimize the indoor Thermal Comfort (TC), Indoor Air Quality (IAQ) and energy use....

  6. Subjective sleep quality in stable neuromuscular patients under non-invasive ventilation.

    Science.gov (United States)

    Crescimanno, Grazia; Misuraca, Angela; Purrazzella, Giuseppina; Greco, Francesca; Marrone, Oreste

    2014-10-01

    Patients with neuromuscular diseases improve their sleep when treated with noninvasive ventilation (NIV), but their sleep architecture during NIV may still be disturbed by side effects of NIV or inadequacy of the ventilator setting. Little is known about subjective sleep quality during NIV. The aims of this study were to evaluate subjective sleep quality of stable neuromuscular patients under long-term NIV by using Pittsburgh questionnaire (PSQI), and to assess its possible determinants. Fifty stable neuromuscular patients under long-term NIV were administered PSQI and underwent polysomnography. Arterial blood gases, forced vital capacity, and respiratory muscular strength were measured. Thirty-three patients had global PSQI ≥ 5 and were classified as bad sleepers. Good and poor sleepers differed in age (P = 0.005), base excess (BE) (P = 0.02), NIV inspiratory pressure (P = 0.04), %N1 (P = 0.0006), and %N3 sleep stage (P = 0.02). Percent N3 duration and Arousal/Awakening Index were correlated with rate of patient-ventilator asynchronies (r = -0.41 and 0.37, respectively, P sleep quality is often poor in neuromuscular patients under long-term NIV. Amount of slow wave sleep and chronic hypoventilation resulting in increased BE are independent predictors of subjective sleep quality. Since inadequate NIV setting or application can influence sleep structure and alveolar ventilation, great care should be paid to the setting and the correct application of NIV to ensure a better subjective sleep quality. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. Noninvasive positive pressure ventilation in subjects with stable COPD: a randomized trial

    Directory of Open Access Journals (Sweden)

    Bhatt SP

    2013-11-01

    Full Text Available Surya P Bhatt,1 Michael W Peterson,2 Jeffrey S Wilson,1 Lakshmi Durairaj1 1Division of Pulmonary, Critical Care, and Occupational Medicine, Department of Internal Medicine, Roy J and Lucille A, Carver College of Medicine, University of Iowa Hospital, Iowa City, IA, USA; 2Department of Medicine, UCSF Fresno Medical Education Program, Fresno, CA, USA Background: The use of domiciliary noninvasive positive pressure ventilation (NPPV in stable chronic obstructive pulmonary disease (COPD with chronic hypercapnic respiratory failure has yielded variable effects on survival, quality of life, and dyspnea. We hypothesized that use of NPPV in stable COPD and partial pressure of carbon dioxide (PaCO2 <52 mmHg might result in improvement in quality of life and dyspnea. Methods: Thirty patients with stable COPD (forced expiratory volume in the first second <50% predicted and PaCO2 <52 mmHg were prospectively randomized to receive domiciliary NPPV (bilevel positive airway pressure, 15/5 cm H2O or usual therapy for 6 months. Measurements were made at baseline, 6 weeks, 3 months, and 6 months. Primary outcomes were quality of life as assessed by the Chronic Respiratory Disease Questionnaire (CRQ, and dyspnea as measured by the Transitional Dyspnea Index (TDI. Results: Fifteen subjects in the NPPV arm and 12 controls completed all the study visits. At 6 weeks and 3 months, the NPPV arm showed significant improvement in TDI total score. However, this effect persisted only in the TDI-Task at 6 months (P=0.03. NPPV use was associated with a small improvement in the CRQ-Mastery domain (0.6 versus –0.1, P=0.04. The arterial partial pressure of oxygen (PaO2 in the control arm worsened over the period of the study, whereas it remained stable in the NPPV arm (change –7.2 mmHg versus +2.1 mmHg, respectively, P=0.02. Conclusion: NPPV resulted in a small improvement in quality of life indices in stable COPD patients with PaCO2 <52 mmHg. Future larger studies will

  8. [Comparative studies of the circulatory system during high frequency inspiratory ventilation and inspiratory positive pressure ventilation].

    Science.gov (United States)

    Nestorowicz, A; Powała-Niedźwiecki, K

    1989-02-06

    The studies were carried out in 14 dogs in which two different ventilation techniques were used under the general anaesthesia: HFIV and IPPV. Functioning of the cardio-vascular system was evaluated, basing on the measurements of pulse rate, pressure in the peripheral vessels, pulmonary artery and central venous pressure and calculation of the stroke volume, cardiac index, and pulmonary vessels resistance index. It was found that both techniques of ventilation did not exert any effect on the functioning of cardio-vascular system. Stroke volume was lower during IPPV than that during HFIV ventilation.

  9. Advanced Controls for Residential Whole-House Ventilation Systems

    Energy Technology Data Exchange (ETDEWEB)

    Turner, William [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Walker, Iain [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Sherman, Max [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2014-08-01

    Whole-house ventilation systems are becoming commonplace in new construction, remodeling/renovation, and weatherization projects, driven by combinations of specific requirements for indoor air quality (IAQ), health and compliance with standards, such as ASHRAE 62.2. Ventilation systems incur an energy penalty on the home via fan power used to drive the airflow, and the additional space-conditioning load associated with heating or cooling the ventilation air. Finding a balance between IAQ and energy use is important if homes are to be adequately ventilated while not increasing the energy burden. This study used computer simulations to examine RIVEC the Residential Integrated Ventilation Controller - a prototype ventilation controller that aims to deliver whole-house ventilation rates that comply with ventilation standards, for the minimum use of energy. Four different whole-house ventilation systems were simulated, both with and without RIVEC, so that the energy and IAQ results could be compared. Simulations were conducted for 13 US climate zones, three house designs, and three envelope leakage values. The results showed that the RIVEC controller could typically return ventilation energy savings greater than 40percent without compromising long-term chronic or short-term acute exposures to relevant indoor contaminants. Critical and average peak power loads were also reduced as a consequence of using RIVEC.

  10. Calculation of Industrial Enterprise Ventilation System by Network Integral Method

    Directory of Open Access Journals (Sweden)

    Mihienkova Evgeniya I.

    2016-01-01

    Full Text Available This paper describe a ventilation system calculation of the technology building industrial enterprise. On the basis of the calculation model for the enterprise offered technical decision of ventilation systems, subject to a compliance exchange multiplicity, purification efficiency, decontamination from the work area; provided the required volume of gas extraction from process equipment according to the sanitary standards and environmental requirements. Produced selection of ventilation equipment parameters, solved the problem of the air exchange balancing between ventilation systems to prevent the emergence of parasitic flows between the rooms building. SigmaNet software package was used for the implement the calculation.

  11. Energy efficient biological air cleaning for farm stable ventilation; Energieffektiv biologisk luftrensning til staldventilation

    Energy Technology Data Exchange (ETDEWEB)

    Groenborg Nicolaisen, C.; Hansen, Mads P.R. [Teknologisk Institut, Aarhus (Denmark); Stroem, J.; Soerensen, Keld [DXT. Danish Exergy Technology A/S, Skoerping (Denmark); Goetke, C. [Lokalenergi Aarhus, Viby J. (Denmark); Morsing, S.; Soerensen, Lars C. [SKOV A/S, Roslev (Denmark); Ladegaerd Jensen, T.; Pedersen, Poul [Videncenter for svineproduktion, Copenhagen (Denmark)

    2013-05-01

    The project has been designed to reduce energy consumption for air purification by 30% while having a payback period of maximum 3 years. The project has achieved very significant results which are far above the target. Particularly satisfying is the wide range of new components that are launched in late 2012. By implementing the newly developed system at 100% cleaning (LPC 13 ventilators and Dynamic multistep control) in relation to Best Practice (SKOV's original system with DA600 fans) in a concrete pigsty, a saving of 61% and a simple payback of 1.7 years is achieved. Similarly, it is found that the energy used for pump operation can be reduced by 37% with the new Dynamic sprinkling control. At 20% cleaning a potential saving of 15% per year and a payback period of between 0 and 5 years was found, which is dependent on the desired performance as the capacities in the bio-filter's upper capacity range between 26 thousand to 30 thousand m3 / h entails costs for an additional extraction unit in the new solution. Furthermore, the newly developed components proved highly suitable for standard installations without air cleaning where a savings potential is 53% and the payback period 1.5 years. Product-wise, the project formed the basis for the development of: 1. New energy-efficient ventilation units (LPC11, 12,13) that are suitable for air purification; 2. A new energy-saving control principle (Dynamic Multi-Step) which is particularly suitable for low-energy ventilators; 3. A new energy-saving flow measurement system for ventilating ducts (Dynamic air to the central exhaust); 4. An energy-saving pressure control in common ducts (pressure control as a function of outside temperature); 5. Proposal for a new energy-saving pump operation for sprinkling of biological filters (Dynamic sprinkling). (LN)

  12. Ventilation Systems Operating Experience Review for Fusion Applications

    Energy Technology Data Exchange (ETDEWEB)

    L. C. Cadwallader

    1999-12-01

    This report is a collection and review of system operation and failure experiences for air ventilation systems in nuclear facilities. These experiences are applicable for magnetic and inertial fusion facilities since air ventilation systems are support systems that can be considered generic to nuclear facilities. The report contains descriptions of ventilation system components, operating experiences with these systems, component failure rates, and component repair times. Since ventilation systems have a role in mitigating accident releases in nuclear facilities, these data are useful in safety analysis and risk assessment of public safety. An effort has also been given to identifying any safety issues with personnel operating or maintaining ventilation systems. Finally, the recommended failure data were compared to an independent data set to determine the accuracy of individual values. This comparison is useful for the International Energy Agency task on fusion component failure rate data collection.

  13. A RESEARCH ON VENTILATION EFFICIENCY OF PIPED VENTILATION SYSTEMS IN GEOTHERMALLY HEATED GREENHOUSES

    Directory of Open Access Journals (Sweden)

    İbrahim Örüng

    2016-07-01

    Full Text Available Greenhouse play significant roles in human nutrition. Vegetable and fruit consumption at certain amounts is the basic pre-condition for a well nutrition. It is possible to produce sufficient quantities of fruits and vegetables in places with available climate conditions. However, fruits and vegetables should be grown in special buildings to have a year-long production in places without available climate conditions. These places include under-cover production facilities, greenhouses, low and high tunnel facilities. Environmental conditions are adjusted are adjusted in greenhouses as to provide proper conditions for plant growth and development. Ventilation is used to remove excess heat, moisture and carbon dioxide from the greenhouses. Either natural or mechanical ventilation is used in greenhouses. Mechanical ventilation systems have various advantages over natural systems. However, mostly natural ventilation systems are preferred because of their low installation and operational costs. Both systems operates based on negative pressure. Air exchange rates are usually low in winters and it is quite hard to evenly distribute cold fresh air within the greenhouse. Air inlets are usually placed over side walls and outlets are commonly placed along the ridge. In this study an alternative natural ventilation system was proposed for more efficient ventilation of the greenhouses. In this system, fresh air gets into the greenhouse through ventilation pipes installed beneath the greenhouse floor. The incoming fresh air also heated with geothermal hot water lines, thus direct contact of cold fresh air is prevented. The design and efficiency of piped ventilation systems were provided in this paper.

  14. Measure Guideline: Selecting Ventilation Systems for Existing Homes

    Energy Technology Data Exchange (ETDEWEB)

    Aldrich, Robb [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2014-02-01

    This document addresses adding -or improving - mechanical ventilation systems to existing homes. The purpose of ventilation is to remove contaminants from homes, and this report discusses where, when, and how much ventilation is appropriate in a home, including some discussion of relevant codes and standards. Advantages, disadvantages, and approximate costs of various system types are presented along with general guidelines for implementing the systems in homes. CARB intends for this document to be useful to decision makers and contractors implementing ventilation systems in homes. Choosing the "best" system is not always straightforward; selecting a system involves balancing performance, efficiency, cost, required maintenance, and several other factors. It is the intent of this document to assist contractors in making more informed decisions when selecting systems. Ventilation is an integral part of a high-performance home. With more air-sealed envelopes, a mechanical means of removing contaminants is critical for indoor environmental quality and building durability.

  15. Fire protection countermeasures for containment ventilation systems

    Energy Technology Data Exchange (ETDEWEB)

    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.

  16. Uncertainties in different level assessments of domestic ventilation systems

    NARCIS (Netherlands)

    Bokel, R.M.J.; Yang, Z.; Cauberg, J.J.M.

    2013-01-01

    In order to improve the quality of ventilation systems, assessments are widely used. In this paper, 3 main assessment levels are distinguished based on the number of ventilation systems to be assessed and the assessment objective. The main assessment levels distinguished in this paper are global

  17. Mask proportional assist vs pressure support ventilation in patients in clinically stable condition with chronic ventilatory failure.

    Science.gov (United States)

    Porta, Roberto; Appendini, Lorenzo; Vitacca, Michele; Bianchi, Luca; Donner, Claudio F; Poggi, Roberta; Ambrosino, Nicolino

    2002-08-01

    To compare the short-term physiologic effects of mask pressure support ventilation (PSV) and proportional assist ventilation (PAV) in patients in clinically stable condition with chronic ventilatory failure (CVF). Randomized, controlled physiologic study. Lung function units of two pulmonary rehabilitation centers. Eighteen patients with CVF caused by COPD (11 patients) and restrictive chest wall diseases (RCWDs) [7 patients]. Assessment of breathing pattern and minute ventilation (E), respiratory muscles and lung mechanics, and patient/ventilator interaction during both unassisted and assisted ventilation. After baseline assessment during spontaneous breathing (SB), mask PSV and PAV were randomly applied at the patient's comfort, with the addition of the same level of continuous positive airway pressure (2 cm H2O or 4 cm H2O in all patients), for 30 min each, with a 20-min interval of SB between periods of assisted ventilation. A longer time was spent to set PAV than PSV (663 +/- 179 s and 246 +/- 58 s, respectively; p variation coefficient, 16.3% +/- 10.5% vs 11.6% +/- 7.7%, respectively; p ventilator interaction between ventilatory modes.

  18. Ventilation System Effectiveness and Tested Indoor Air Quality Impacts

    Energy Technology Data Exchange (ETDEWEB)

    Rudd, Armin [Building Science Corporation, Somerville, MA (United States); Bergey, Daniel [Building Science Corporation, Somerville, MA (United States)

    2014-02-01

    In this project, Building America research team Building Science Corporation tested the effectiveness of ventilation systems at two unoccupied, single-family, detached lab homes at the University of Texas - Tyler. Five ventilation system tests were conducted with various whole-building ventilation systems. Multizone fan pressurization testing characterized building and zone enclosure leakage. PFT testing showed multizone air change rates and interzonal airflow. Cumulative particle counts for six particle sizes, and formaldehyde and other Top 20 VOC concentrations were measured in multiple zones. The testing showed that single-point exhaust ventilation was inferior as a whole-house ventilation strategy. This was because the source of outside air was not direct from outside, the ventilation air was not distributed, and no provision existed for air filtration. Indoor air recirculation by a central air distribution system can help improve the exhaust ventilation system by way of air mixing and filtration. In contrast, the supply and balanced ventilation systems showed that there is a significant benefit to drawing outside air from a known outside location, and filtering and distributing that air. Compared to the exhaust systems, the CFIS and ERV systems showed better ventilation air distribution and lower concentrations of particulates, formaldehyde and other VOCs. System improvement percentages were estimated based on four system factor categories: balance, distribution, outside air source, and recirculation filtration. Recommended system factors could be applied to reduce ventilation fan airflow rates relative to ASHRAE Standard 62.2 to save energy and reduce moisture control risk in humid climates. HVAC energy savings were predicted to be 8-10%, or $50-$75/year.

  19. Ventilation System Effectiveness and Tested Indoor Air Quality Impacts

    Energy Technology Data Exchange (ETDEWEB)

    Rudd, Armin [National Renewable Energy Lab. (NREL), Golden, CO (United States); Bergey, Daniel [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2014-02-01

    Ventilation system effectiveness testing was conducted at two unoccupied, single-family, detached lab homes at the University of Texas - Tyler. Five ventilation system tests were conducted with various whole-building ventilation systems. Multizone fan pressurization testing characterized building and zone enclosure leakage. PFT testing showed multizone air change rates and interzonal airflow. Cumulative particle counts for six particle sizes, and formaldehyde and other Top 20 VOC concentrations were measured in multiple zones. The testing showed that single-point exhaust ventilation was inferior as a whole-house ventilation strategy. It was inferior because the source of outside air was not direct from outside, the ventilation air was not distributed, and no provision existed for air filtration. Indoor air recirculation by a central air distribution system can help improve the exhaust ventilation system by way of air mixing and filtration. In contrast, the supply and balanced ventilation systems showed that there is a significant benefit to drawing outside air from a known outside location, and filtering and distributing that air. Compared to the Exhaust systems, the CFIS and ERV systems showed better ventilation air distribution and lower concentrations of particulates, formaldehyde and other VOCs. System improvement percentages were estimated based on four System Factor Categories: Balance, Distribution, Outside Air Source, and Recirculation Filtration. Recommended System Factors could be applied to reduce ventilation fan airflow rates relative to ASHRAE Standard 62.2 to save energy and reduce moisture control risk in humid climates. HVAC energy savings were predicted to be 8-10%, or $50-$75/year.

  20. YMP Engineered Barrier Systems Scaled Ventilation Testing

    Energy Technology Data Exchange (ETDEWEB)

    S.D. Dunn; B. Lowry; B. Walsh; J.D. Mar; C. Howard; R. Johnston; T. Williams

    2002-11-22

    Yucca Mountain, approximately 100 miles northwest of Las Vegas, Nevada, has been selected as the site for the nation's first geologic repository for high level nuclear waste. The Yucca Mountain Project (YMP) is currently developing the design for the underground facilities. Ventilation is a key component of the design as a way to maintain the desired thermal conditions in the emplacement drifts prior to closure. As a means of determining the effects of continuous ventilation on heat removal from the emplacement drifts two series of scaled ventilation tests have been performed. Both test series were performed in the DOE/North Las Vegas Atlas facility. The tests provided scaled (nominally 25% of the full scale emplacement drift design) thermal and flow process data that will be used to validate YMP heat and mass transport codes. The Phase I Ventilation Test series evaluated the ability of ambient ventilation air to remove energy under varying flow and input power conditions. The Phase II Ventilation Test series evaluated the ability of pre-conditioned ventilation air to remove energy under varying flow, input temperature and moisture content, and simulated waste package input power conditions. Twenty-two distinct ventilation tests were run.

  1. High intensity positive pressure ventilation and long term pulmonary function responses in severe stable COPD. A delicate and difficult balance.

    Science.gov (United States)

    Esquinas, Antonio M; Petroianni, Angelo

    2014-06-01

    Method to improve minute ventilation (MV) during spontaneous breathing (SB) in stable severe chronic obstructive pulmonary disease (COPD) have a great clinical relevant in long term outcome. In this scenario, recommendations of early use of high-Intensity non-invasive Positive pressure Ventilation (HI-NPPV) or intelligent Volume Assured Pressure (iVAP) Support in Hypercapnic COPD have been proposed by safe therapeutics options. We analyze in this letter, Ekkernkamp et al. study that described the effect of HI-NPPV compared with SB on MV in patients receiving long-term treatment. We consider that interpretation of relationships between ABG, functional parameters, and respiratory mechanics reported need clarifications. Further prospective large clinical trials identifying the best mode of ventilation according to the characteristics in severe stable COPD are necessary to balance an effective approach and response on clinical symptoms and long-term effects.

  2. On analysis of operating efficiency of autonomous ventilation systems

    Directory of Open Access Journals (Sweden)

    Kostuganov Arman

    2017-01-01

    Full Text Available The paper deals with the causes and consequences of malfunctioning of natural and mechanical ventilation systems in civil buildings of Russia. Furthermore it gives their classification and analysis based on the literature review. On the basis of the analysis technical solutions for improving the efficiency of ventilation systems in civil buildings are summarized and the field of their application is specified. Among the offered technical solutions the use of autonomous ventilation systems with heat recovery is highlighted as one of the most promising and understudied. Besides it has a wide range of applications. The paper reviews and analyzes the main Russian and foreign designs of ventilation systems with heat recovery that are mostly used in practice. Three types of such systems: UVRK-50, Prana-150, ТеFо are chosen for consideration. The sequence of field tests of selected autonomous ventilation systems have been carried out in order to determine the actual air exchange and efficiency of heat recovery. The paper presents the processed results of the research on the basis of which advantages and disadvantages of the tested ventilation systems are identified and recommendations for engineering and manufacturing of new design models of autonomous ventilation systems with heat recovery are formulated.

  3. Nocturnal non-invasive nasal ventilation in stable hypercapnic COPD: a randomised controlled trial.

    Science.gov (United States)

    McEvoy, R D; Pierce, R J; Hillman, D; Esterman, A; Ellis, E E; Catcheside, P G; O'Donoghue, F J; Barnes, D J; Grunstein, R R

    2009-07-01

    Sleep hypoventilation has been proposed as a cause of progressive hypercapnic respiratory failure and death in patients with severe chronic obstructive pulmonary disease (COPD). A study was undertaken to determine the effects of nocturnal non-invasive bi-level pressure support ventilation (NIV) on survival, lung function and quality of life in patients with severe hypercapnic COPD. A multicentre, open-label, randomised controlled trial of NIV plus long-term oxygen therapy (LTOT) versus LTOT alone was performed in four Australian University Hospital sleep/respiratory medicine departments in patients with severe stable smoking-related COPD (forced expiratory volume in 1 s (FEV1.0) arterial carbon dioxide tension (PaCO2) >46 mm Hg and on LTOT for at least 3 months) and age 20/h) or morbid obesity (body mass index >40) were excluded. Outcome measures were survival, spirometry, arterial blood gases, polysomnography, general and disease-specific quality of life and mood. 144 patients were randomised (72 to NIV + LTOT and 72 to LTOT alone). NIV improved sleep quality and sleep-related hypercapnia acutely, and patients complied well with therapy (mean (SD) nightly use 4.5 (3.2) h). Compared with LTOT alone, NIV (mean follow-up 2.21 years, range 0.01-5.59) showed an improvement in survival with the adjusted but not the unadjusted Cox model (adjusted hazard ratio (HR) 0.63, 95% CI 0.40 to 0.99, p = 0.045; unadjusted HR 0.82, 95% CI 0.53 to 1.25, p = NS). FEV1.0 and PaCO2 measured at 6 and 12 months were not different between groups. Patients assigned to NIV + LTOT had reduced general and mental health and vigour. Nocturnal NIV in stable oxygen-dependent patients with hypercapnic COPD may improve survival, but this appears to be at the cost of worsening quality of life. ACTRN12605000205639.

  4. Measure Guideline: Selecting Ventilation Systems for Existing Homes

    Energy Technology Data Exchange (ETDEWEB)

    Aldrich, R. [Consortium for Advanced Residential Buildings (CARB), Norwalk, CT (United States)

    2014-02-01

    This report, developed by Building America research team CARB, addresses adding or improving mechanical ventilation systems to existing homes. The goal of this report is to assist decision makers and contractors in making informed decisions when selecting ventilation systems for homes. With more air-sealed envelopes, a mechanical means of removing contaminants is critical for indoor environmental quality and building durability. The purpose of ventilation is to remove contaminants from homes, and this report discusses where, when, and how much ventilation is appropriate in a home, including examination of relevant codes and standards. Choosing the "best" system is not always straightforward; selecting a system involves balancing performance, efficiency, cost, required maintenance, and several other factors.

  5. Characterization of natural ventilation in wastewater collection systems.

    Science.gov (United States)

    Ward, Matthew; Corsi, Richard; Morton, Robert; Knapp, Tom; Apgar, Dirk; Quigley, Chris; Easter, Chris; Witherspoon, Jay; Pramanik, Amit; Parker, Wayne

    2011-03-01

    The purpose of the study was to characterize natural ventilation in full-scale gravity collection system components while measuring other parameters related to ventilation. Experiments were completed at four different locations in the wastewater collection systems of Los Angeles County Sanitation Districts, Los Angeles, California, and the King County Wastewater Treatment District, Seattle, Washington. The subject components were concrete gravity pipes ranging in diameter from 0.8 to 2.4 m (33 to 96 in.). Air velocity was measured in each pipe using a carbon-monoxide pulse tracer method. Air velocity was measured entering or exiting the components at vents using a standpipe and hotwire anemometer arrangement. Ambient wind speed, temperature, and relative humidity; headspace temperature and relative humidity; and wastewater flow and temperature were measured. The field experiments resulted in a large database of measured ventilation and related parameters characterizing ventilation in full-scale gravity sewers. Measured ventilation rates ranged from 23 to 840 L/s. The experimental data was used to evaluate existing ventilation models. Three models that were based upon empirical extrapolation, computational fluid dynamics, and thermodynamics, respectively, were evaluated based on predictive accuracy compared to the measured data. Strengths and weaknesses in each model were found and these observations were used to propose a concept for an improved ventilation model.

  6. Respiratory muscle activity and patient–ventilator asynchrony during different settings of noninvasive ventilation in stable hypercapnic COPD: does high inspiratory pressure lead to respiratory muscle unloading?

    Directory of Open Access Journals (Sweden)

    Duiverman ML

    2017-01-01

    Full Text Available Marieke L Duiverman,1 Anouk S Huberts,2 Leo A van Eykern,3 Gerrie Bladder,1 Peter J Wijkstra1 1Department of Pulmonary Diseases and Home Mechanical Ventilation, University Medical Centre Groningen, 2Faculty of Medical Sciences, University of Groningen, 3Inbiolab B.V., Groningen, the Netherlands Introduction: High-intensity noninvasive ventilation (NIV has been shown to improve outcomes in stable chronic obstructive pulmonary disease patients. However, there is insufficient knowledge about whether with this more controlled ventilatory mode optimal respiratory muscle unloading is provided without an increase in patient–ventilator asynchrony (PVA. Patients and methods: Ten chronic obstructive pulmonary disease patients on home mechanical ventilation were included. Four different ventilatory settings were investigated in each patient in random order, each for 15 min, varying the inspiratory positive airway pressure and backup breathing frequency. With surface electromyography (EMG, activities of the intercostal muscles, diaphragm, and scalene muscles were determined. Furthermore, pressure tracings were derived simultaneously in order to assess PVA. Results: Compared to spontaneous breathing, the most pronounced decrease in EMG activity was achieved with the high-pressure settings. Adding a high breathing frequency did reduce EMG activity per breath, while the decrease in EMG activity over 1 min was comparable with the high-pressure, low-frequency setting. With high backup breathing frequencies less breaths were pressure supported (25% vs 97%. PVAs occurred more frequently with the low-frequency settings (P=0.017. Conclusion: High-intensity NIV might provide optimal unloading of respiratory muscles, without undue increases in PVA. Keywords: electromyography, high-intensity NIV, chronic obstructive pulmonary disease, ineffective efforts

  7. Preoperational test report, primary ventilation condenser cooling system

    Energy Technology Data Exchange (ETDEWEB)

    Clifton, F.T.

    1997-10-29

    This represents the preoperational test report for the Primary Ventilation Condenser Cooling System, Project W-030. Project W-030 provides a ventilation upgrade for the four Aging Waste Facility tanks. The system uses a closed chilled water piping loop to provide offgas effluent cooling for tanks AY101, AY102, AZ1O1, AZ102; the offgas is cooled from a nominal 100 F to 40 F. Resulting condensation removes tritiated vapor from the exhaust stack stream. The piping system includes a package outdoor air-cooled water chiller with parallel redundant circulating pumps; the condenser coil is located inside a shielded ventilation equipment cell. The tests verify correct system operation and correct indications displayed by the central Monitor and Control System.

  8. Mixing Ventilation System in a Single-Aisle Aircraft Cabin

    DEFF Research Database (Denmark)

    Nielsen, Peter Vilhelm; Zhang, Chen; Wojcik, Kamil

    2014-01-01

    Traditionally, air is supplied to the aircraft cabin either by individual nozzles or by supply slots. The air is expected to be fully mixed in the cabin, and the system is considered to be a mixing ventilation system. This paper will provide measurements on the mixing flow in an aircraft cabin...... and present a design procedure of the system. Finally, a personalised ventilation system will be described, which can be used together with the mixing ventilation system. The experiments are made in a full-scale, left side mock-up of a single-aisle (Boeing 737) cabin with four seats. The four passengers...... are simulated by thermal manikins. Velocity, temperature and cross-infection risk are measured. The experiments proved that fully developed turbulent flow will take place in the cabin and that the flow element theory can be used for the design procedure when the air flow rate is above a certain level...

  9. Design of energy efficient ventilation and air-conditioning systems

    CERN Document Server

    Seppänen, Olli; Bertilsson, Thore; Maripuu, Mari-Liis; Lamy, Hervé; Vanden Borre, Alex

    2012-01-01

    This guidebook covers numerous system components of ventilation and air-conditioning systems and shows how they can be improved by applying the latest technology products. Special attention is paid to details, which are often overlooked in the daily design practice, resulting in poor performance of high quality products once they are installed in the building system.

  10. Implementation and assessment of a novel mechanical ventilatory system following a noisy ventilation regime

    OpenAIRE

    Marcus Henrique Victor Júnior

    2014-01-01

    This study concerns the development of a novel mechanical ventilation system, with a view to analysing the results of a new mechanical ventilation technique, referred to noisy ventilation. Additionally, the study addresses the assessment of the system, involving the estimation of certain mechanical parameters of the respiratory system under noisy ventilation and discusses a pilot trial in vivo, with a pig. During acute respiratory failure, intubation and invasive mechanical ventilation may be...

  11. Stable wafer-carrier system

    Energy Technology Data Exchange (ETDEWEB)

    Rozenzon, Yan; Trujillo, Robert T; Beese, Steven C

    2013-10-22

    One embodiment of the present invention provides a wafer-carrier system used in a deposition chamber for carrying wafers. The wafer-carrier system includes a base susceptor and a top susceptor nested inside the base susceptor with its wafer-mounting side facing the base susceptor's wafer-mounting side, thereby forming a substantially enclosed narrow channel. The base susceptor provides an upward support to the top susceptor.

  12. Water spray ventilator system for continuous mining machines

    Science.gov (United States)

    Page, Steven J.; Mal, Thomas

    1995-01-01

    The invention relates to a water spray ventilator system mounted on a continuous mining machine to streamline airflow and provide effective face ventilation of both respirable dust and methane in underground coal mines. This system has two side spray nozzles mounted one on each side of the mining machine and six spray nozzles disposed on a manifold mounted to the underside of the machine boom. The six spray nozzles are angularly and laterally oriented on the manifold so as to provide non-overlapping spray patterns along the length of the cutter drum.

  13. A decision support system to determine optimal ventilator settings.

    Science.gov (United States)

    Akbulut, Fatma Patlar; Akkur, Erkan; Akan, Aydin; Yarman, B Siddik

    2014-01-10

    Choosing the correct ventilator settings for the treatment of patients with respiratory tract disease is quite an important issue. Since the task of specifying the parameters of ventilation equipment is entirely carried out by a physician, physician's knowledge and experience in the selection of these settings has a direct effect on the accuracy of his/her decisions. Nowadays, decision support systems have been used for these kinds of operations to eliminate errors. Our goal is to minimize errors in ventilation therapy and prevent deaths caused by incorrect configuration of ventilation devices. The proposed system is designed to assist less experienced physicians working in the facilities without having lung mechanics like cottage hospitals. This article describes a decision support system proposing the ventilator settings required to be applied in the treatment according to the patients' physiological information. The proposed model has been designed to minimize the possibility of making a mistake and to encourage more efficient use of time in support of the decision making process while the physicians make critical decisions about the patient. Artificial Neural Network (ANN) is implemented in order to calculate frequency, tidal volume, FiO2 outputs, and this classification model has been used for estimation of pressure support / volume support outputs. For the obtainment of the highest performance in both models, different configurations have been tried. Various tests have been realized for training methods, and a number of hidden layers mostly affect factors regarding the performance of ANNs. The physiological information of 158 respiratory patients over the age of 60 and were treated in three different hospitals between the years 2010 and 2012 has been used in the training and testing of the system. The diagnosed disease, core body temperature, pulse, arterial systolic pressure, diastolic blood pressure, PEEP, PSO2, pH, pCO2, bicarbonate data as well as the

  14. Radioactive waste tank ventilation system incorporating tritium control

    Energy Technology Data Exchange (ETDEWEB)

    Rice, P.D. [ICF Kaiser Hanford Company, Richland, WA (United States)

    1997-08-01

    This paper describes the development of a ventilation system for radioactive waste tanks at the U.S. Department of Energy`s (DOE) Hanford Site in Richland, Washington. The unique design of the system is aimed at cost-effective control of tritiated water vapor. The system includes recirculation ventilation and cooling for each tank in the facility and a central exhaust air clean-up train that includes a low-temperature vapor condenser and high-efficiency mist eliminator (HEME). A one-seventh scale pilot plant was built and tested to verify predicted performance of the low-temperature tritium removal system. Tests were conducted to determine the effectiveness of the removal of condensable vapor and soluble and insoluble aerosols and to estimate the operating life of the mist eliminator. Definitive design of the ventilation system relied heavily on the test data. The unique design features of the ventilation system will result in far less release of tritium to the atmosphere than from conventional high-volume dilution systems and will greatly reduce operating costs. NESHAPs and TAPs NOC applications have been approved, and field construction is nearly complete. Start-up is scheduled for late 1996. 3 refs., 4 figs., 2 tabs.

  15. Effective, industrial ventilation systems. New generation of ventilation systems under development; Effectieve, industriele ventilatiesystemen

    Energy Technology Data Exchange (ETDEWEB)

    Moons, A.; Knoll, B. [TNO Bouw en Ondergrond, Delft (Netherlands)

    2008-02-15

    Industrial processes and tools can expose employees to various harmful substances. This is a burden that often takes place decentralized. Room ventilation alone usually does not offer enough protection. New ventilation concepts can offer employees effective protection. (mk) [Dutch] Industriele processen en gereedschappen kunnen werknemers blootstellen aan allerlei schadelijke stoffen. Een belasting die vaak zeer decentraal plaatsheeft. Alleen ruimteventilatie biedt doorgaans onvoldoende bescherming. Nieuwe ventilatieconcepten kunnen medewerkers wel een effectieve bescherming bieden.

  16. Experimental Study of Air Distribution and Ventilation Effectiveness in a Room with a Combination of Different Mechanical Ventilation and Heating/Cooling Systems

    DEFF Research Database (Denmark)

    Olesen, Bjarne W.; Simone, Angela; Krajcik, Michal

    2011-01-01

    Mixing and displacement ventilation are common systems in commercial buildings, while mixing ventilation is used in residential buildings. Displacement ventilation provides fresh air to the occupied zone in a more efficient way than mixing ventilation but it is important to know how well it works...

  17. [Air quality control systems: heating, ventilating, and air conditioning (HVAC)].

    Science.gov (United States)

    Bellucci Sessa, R; Riccio, G

    2004-01-01

    After a brief illustration of the principal layout schemes of Heating, Ventilating, and Air Conditioning (HVAC), the first part of this paper summarizes the standards, both voluntary and compulsory, regulating HVAC facilities design and installation with regard to the question of Indoor Air Quality (IAQ). The paper then examines the problem of ventilation systems maintenance and the essential hygienistic requirements in whose absence HVAC facilities may become a risk factor for people working or living in the building. Lastly, the paper deals with HVAC design strategies and methods, which aim not only to satisfy comfort and air quality requirements, but also to ensure easy and effective maintenance procedures.

  18. Availability Analysis of the Ventilation Stack CAM Interlock System

    CERN Document Server

    Young, J

    2000-01-01

    Ventilation Stack Continuous Air Monitor (CAM) Interlock System failure modes, failure frequencies, and system availability have been evaluated for the RPP. The evaluation concludes that CAM availability is as high as assumed in the safety analysis and that the current routine system surveillance is adequate to maintain this availability credited in the safety analysis, nor is such an arrangement predicted to significantly improve system availability.

  19. Heating, Ventilation and Air-Conditioning Systems, Part of Indoor Air Quality Design Tools for Schools

    Science.gov (United States)

    The main purposes of a Heating, Ventilation, and Air-Conditioning system are to help maintain good indoor air quality through adequate ventilation with filtration and provide thermal comfort. HVAC systems are among the largest energy consumers in schools.

  20. Possible scenarios for a safety upgrade of the ventilation system

    CERN Document Server

    Inigo-Golfin, J

    2009-01-01

    This paper/presentation describes the existing LHC ventilation (HVAC) system, the design principle followed for the LEP Project and the modifications implemented for the LHC Project. A discussion on possible referential standards to compare the existing system with is presented and possible axes for its improvement, based on these referentials, are discussed. Finally, some recommendations are given based on the system's present capabilities and the estimated investment necessary to achieve compliance to the referentials chosen.

  1. Pressure Dynamic Characteristics of Pressure Controlled Ventilation System of a Lung Simulator

    OpenAIRE

    Yan Shi; Shuai Ren; Maolin Cai; Weiqing Xu; Qiyou Deng

    2014-01-01

    Mechanical ventilation is an important life support treatment of critically ill patients, and air pressure dynamics of human lung affect ventilation treatment effects. In this paper, in order to obtain the influences of seven key parameters of mechanical ventilation system on the pressure dynamics of human lung, firstly, mechanical ventilation system was considered as a pure pneumatic system, and then its mathematical model was set up. Furthermore, to verify the mathematical model, a prototyp...

  2. VWPS: A Ventilator Weaning Prediction System with Artificial Intelligence

    Science.gov (United States)

    Chen, Austin H.; Chen, Guan-Ting

    How to wean patients efficiently off mechanical ventilation continues to be a challenge for medical professionals. In this paper we have described a novel approach to the study of a ventilator weaning prediction system (VWPS). Firstly, we have developed and written three Artificial Neural Network (ANN) algorithms to predict a weaning successful rate based on the clinical data. Secondly, we have implemented two user-friendly weaning success rate prediction systems; the VWPS system and the BWAP system. Both systems could be used to help doctors objectively and effectively predict whether weaning is appropriate for patients based on the patients' clinical data. Our system utilizes the powerful processing abilities of MatLab. Thirdly, we have calculated the performance through measures such as sensitivity and accuracy for these three algorithms. The results show a very high sensitivity (around 80%) and accuracy (around 70%). To our knowledge, this is the first design approach of its kind to be used in the study of ventilator weaning success rate prediction.

  3. Exposure of ventilation system cleaning workers to harmful microbiological agents.

    Science.gov (United States)

    Gołofit-Szymczak, Małgorzata; Ławniczek-Wałczyk, Anna; Górny, Rafał L

    2013-01-01

    Regular inspection of the cleanliness of the ventilation systems, as well as their periodic cleaning and disinfection, if necessary, are the main factors of the proper maintenance of each system. Performing maintenance operations on the ventilation system, workers are exposed to risk associated with the exposure to harmful biological agents. The aim of this study was to assess the employees' exposure to bioaerosols during maintenance work on ventilation systems. Bioaerosol measurements were carried out using a button sampler. The microbial particles were collected on gelatin filters. Settled-dust samples from the inner surface of the air ducts and filter-mat samples were selected for the microbiological analysis. In the collected air, dust and filter samples the concentration of bacteria and fungi were determined. Bacteria and fungi concentrations ranged between 3.6 x 10(2)-2.2 x 10(4) CFU/m3 and 4.7 x 10(2)-4.5 x 10(3) CFU/m3 at workplaces where the operations connected with mechanical ventilation cleaning were performed and 2.2 x 10(4)-1.2 x 10(5) CFU/m2 and 9.8 x 10(1)-2.5 x 10(2) CFU/m3 at workplaces where filter exchange was performed, respectively. The qualitative analysis of microorganisms isolated from the air in all studied workplaces revealed that the most prevalent bacteria belonged to Bacillus genus. The average concentrations of bacteria and fungi in filter-mat samples were 3.3 x 10(3) CFU/cm2 and 1.4 x 10(4) CFU/cm2, respectively. In settled-dust samples, average concentrations were 591 CFU/100 cm2 and 52 CFU/100 cm2, for bacteria and fungi respectively. Workers cleaning ventilation systems are exposed to harmful biological agents classified into risk groups, 1 and 2, according to their level of the risk of infection. The research conducted in the workplace can be the basis of risk assessment related to exposure to harmful biological agents during maintenance work in ventilation.

  4. Exposure of ventilation system cleaning workers to harmful microbiological agents

    Directory of Open Access Journals (Sweden)

    Małgorzata Gołofit-Szymczak

    2013-10-01

    Full Text Available Background: Regular inspection of the cleanliness of the ventilation systems, as well as their periodic cleaning and disinfection, if necessary, are the main factors of the proper maintenance of each system. Performing maintenance operations on the ventilation system, workers are exposed to risk associated with the exposure to harmful biological agents. The aim of this study was to assess the employees' exposure to bioaerosols during maintenance work on ventilation systems. Material and Methods: Bioaerosol measurements were carried out using a button sampler. The microbial particles were collected on gelatin filters. Settled-dust samples from the inner surface of the air ducts and filter-mat samples were selected for the microbiological analysis. In the collected air, dust and filter samples the concentration of bacteria and fungi were determined. Results: Bacteria and fungi concentrations ranged between 3.6×102-2.2×104 CFU/m3 and 4.7×102-4.5×103 CFU/m3 at workplaces where the operations connected with mechanical ventilation cleaning were performed and 2.2×104-1.2×105 CFU/m3 and 9.8×101-2.5×102 CFU/m3 at workplaces where filter exchange was performed, respectively. The qualitative analysis of microorganisms isolated from the air in all studied workplaces revealed that the most prevalent bacteria belonged to Bacillus genus. The average concentrations of bacteria and fungi in filter-mat samples were 3.3×103 CFU/cm2 and 1.4×104 CFU/cm2, respectively. In settled-dust samples, average concentrations were 591 CFU/100 cm2 and 52 CFU/100 cm2, for bacteria and fungi respectively. Conclusions: Workers cleaning ventilation systems are exposed to harmful biological agents classified into risk groups, 1 and 2, according to their level of the risk of infection. The research conducted in the workplace can be the basis of risk assessment related to exposure to harmful biological agents during maintenance work in ventilation. Med Pr 2013;64(5:613–623

  5. Airflow Sensitivity Assessment Based on Underground Mine Ventilation Systems Modeling

    Directory of Open Access Journals (Sweden)

    Wacław Dziurzyński

    2017-09-01

    Full Text Available This paper presents a method for determining the sensitivity of the main air flow directions in ventilation subnetworks to changes in aerodynamic resistance and air density in mine workings. The authors have developed formulae for determining the sensitivity of the main subnetwork air flows by establishing the degree of dependency of the air volume stream in a given working on the variations in resistance or air density of other workings of the network. They have been implemented in the Ventgraph mine ventilation network simulator. This software, widely used in Polish collieries, provides an extended possibility to predict the process of ventilation, air distribution and, in the case of underground fire, the spread of combustion gasses. The new method facilitates an assessment by mine ventilation services of the stability of ventilation systems in exploitation areas and determines the sensitivity of the main subnetwork air flow directions to changes in aerodynamic resistance and air density. Recently in some Polish collieries new longwalls are developed in seams located deeper than the bottom of the intake shaft. Such a solution is called “exploitation below the level of access” or “sublevel”. The new approach may be applied to such developments to assess the potential of changes in direction and air flow rates. In addition, an interpretation of the developed sensitivity indicator is presented. While analyzing air distributions for sublevel exploitation, the application of current numerical models for calculations of the distribution results in tangible benefits, such as the evaluation of the safety or risk levels for such exploitation. Application of the Ventgraph computer program, and particularly the module POŻAR (fire with the newly developed options, allows for an additional approach to the sensitivity indicator in evaluating air flow safety levels for the risks present during exploitation below the level of the intake shaft. The

  6. Method to assess the performance of ventilation systems in dwellings considering the influence of uncertainties

    NARCIS (Netherlands)

    Yang, Z.; Cauberg, J.J.M.; Tenpierik, M.J.

    2011-01-01

    Normally, the design of a ventilation system in a dwelling is based on national regulations, related design rules, building tradition and general knowledge about healthy indoor air quality, ventilation and air handling units. In practice, the actual performance of ventilation systems is determined

  7. Evaluating Ventilation Systems for Existing Homes

    Energy Technology Data Exchange (ETDEWEB)

    Aldrich, R.; Arena, L.

    2013-02-01

    During the course of this project, an affordable and high performance ductwork system to directly address the problems of thermal losses, poor efficiency, and air leakage was designed. To save space and enable direct connections between different floors of the building, the ductwork system was designed in such a way that it occupied interior or exterior frame wall cavities. The ductwork system satisfied building regulations for structural support when bridging multiple floors, the spread of fire and smoke, and insulation to reduce the heat flow into or out of the building. Retrofits of urban residential buildings will be the main focus for the application of this ductwork system. Highly reflective foils and insulating materials were used to aid in the increase of the overall R-value of the ductwork itself and the wall assembly. It is expected that the proposed system will increase the efficiency of the HVAC system and the thermal resistance of the building envelope. The performance of the proposed ductwork design was numerically evaluated in a number of different ways. Our results indicate that the duct method is a very cost attractive alternative to the conventional method.

  8. Numerical simulation of volume-controlled mechanical ventilated respiratory system with 2 different lungs.

    Science.gov (United States)

    Shi, Yan; Zhang, Bolun; Cai, Maolin; Zhang, Xiaohua Douglas

    2017-09-01

    Mechanical ventilation is a key therapy for patients who cannot breathe adequately by themselves, and dynamics of mechanical ventilation system is of great significance for life support of patients. Recently, models of mechanical ventilated respiratory system with 1 lung are used to simulate the respiratory system of patients. However, humans have 2 lungs. When the respiratory characteristics of 2 lungs are different, a single-lung model cannot reflect real respiratory system. In this paper, to illustrate dynamic characteristics of mechanical ventilated respiratory system with 2 different lungs, we propose a mathematical model of mechanical ventilated respiratory system with 2 different lungs and conduct experiments to verify the model. Furthermore, we study the dynamics of mechanical ventilated respiratory system with 2 different lungs. This research study can be used for improving the efficiency and safety of volume-controlled mechanical ventilation system. Copyright © 2016 John Wiley & Sons, Ltd.

  9. Exergy analysis of ventilation systems with energy recovery

    OpenAIRE

    I.O. Sukhodub; V.I. Deshko

    2014-01-01

    Thermal, mechanical and chemical components of room air exergy and its change depending on the outside air parameters (temperature, humidity and pressure) have been examined for different periods of the year, using the climatic data for Kiev (IWEC). In winter the thermal component dominates, whereas in summer the chemical one prevails. Various approaches to exergy efficiency definition of ventilation systems with energy recovery (namely, a universal, functional and maximum exergy efficien...

  10. Indoor Chemistry: Materials, Ventilation Systems, and Occupant Activities

    Energy Technology Data Exchange (ETDEWEB)

    Morrison, G.C.; Corsi, R.L.; Destaillats, H.; Nazaroff, W.W.; Wells, J.R.

    2006-05-01

    Chemical processes taking place in indoor environments can significantly alter the nature and concentrations of pollutants. Exposure to secondary contaminants generated in these reactions needs to be evaluated in association with many aspects of buildings to minimize their impact on occupant health and well-being. Focusing on indoor ozone chemistry, we describe alternatives for improving indoor air quality by controlling chemical changes related to building materials, ventilation systems, and occupant activities.

  11. How structurally stable are global socioeconomic systems?

    CERN Document Server

    Saavedra, Serguei; Gilarranz, Luis J; Bascompte, Jordi

    2014-01-01

    The stability analysis of socioeconomic systems has been centered on answering whether small perturbations when a system is in a given quantitative state will push the system permanently to a different quantitative state. However, typically the quantitative state of socioeconomic systems is subject to constant change. Therefore, a key stability question that has been under-investigated is how strong the conditions of a system itself can change before the system moves to a qualitatively different behavior, i.e., how structurally stable the systems is. Here, we introduce a framework to investigate the structural stability of socioeconomic systems formed by the network of interactions among agents competing for resources. We measure the structural stability of the system as the range of conditions in the distribution and availability of resources compatible with the qualitative behavior in which all the constituent agents can be self-sustained across time. To illustrate our framework, we study an empirical repre...

  12. Testing and Evaluation of the Bear Medical Systems, Inc. Bear 33 Volume Ventilator System

    Science.gov (United States)

    1990-12-01

    the ventilator and humidifier were attached to a Michigan Instruments Model 1600 mechanical lung analyzer, which simulated the patient’s lungs. We...AD-A241 836 USAFSAM-TR-90-22 TESTING AND EVALUATION OF THE BEAR MEDICAL SYSTEMS, INC. BEAR 33 VOLUME VENTILATOR SYSTEM Teresa R. Lewis, Captain, USAF...Medical Systems, Inc. PE - 62202F Bear 33 Volume Ventilator System PR - 7930 6. AUTHOR(S) TA - 16 WU - 12 Teresa R. Lewis, and Thomas E. Philbeck, Jr. 7

  13. Controlled ventilation with the Mapleson D system A theoretical and experimental study.

    Science.gov (United States)

    Seeley, H F; Barnes, P K; Conway, C M

    1977-02-01

    A theoretical analysis has been performed to show the interrelationships between alveolar carbon dioxide concentration, carbon dioxide output, alveolar ventilation and fresh gas flow during controlled ventilation with the Mapleson D system. The model and forms of equation used have been substantiated by experiments in which dogs were ventilated through a coaxial version of the Mapleson D system at varying levels of fresh gas flow and alveolar ventilation. By assuming that man ventilated with this system behaves as does the dog, a nomogram has been produced to predict alveolar carbon dioxide concentrations at any levels of fresh gas flow and minute volume.

  14. Comparison of physical performances of the ventilation systems in low-energy residential houses

    Energy Technology Data Exchange (ETDEWEB)

    Maier, T. [Buero V. Maier, Hoechstadt, Erlangen (Germany); Krzaczek, M.; Tejchman, J. [Gdansk University of Technology, Faculty of Civil and Environmental Engineering, 80-952 Gdansk-Wrzeszcz, Narutowicza 11/12 (Poland)

    2009-03-15

    The paper presents experimental results of the effect of ventilation systems in modern residential low-energy houses on thermal and humid conditions, heat consumption and perception of thermal comfort and air quality by their residents. Practical projects of modern residential houses with various ventilation systems which realize thermal, humid and psycho-physical comfort were worked out. To analyze the influence of ventilation systems on human comfort, results of questionnaires and comprehensive experimental measurements were taken into account. For measurements, 22 identical residential houses in Germany were chosen where 4 various ventilation systems were installed: gravitational (natural) ventilation, air heating system, mechanical ventilation with in- and out-leading air elements and a function of heat recovery and mechanical ventilation with single ventilators. The following parameters were measured in test units: relative air humidity, concentration of CO{sub 2} in the air, air temperature, consumption of electricity, gas and heat, working time of the window opening, working time of the mechanical ventilation and number of residents. Advantages and disadvantages of ventilation systems were outlined. Experimental results were evaluated. Relationships between ventilation systems and thermal comfort were discussed by taking into account opinions of house residents. (author)

  15. SIMULATION OF FREE CURRENT FLOWS IN BUOYANCY-DRIVEN VENTILATION SYSTEMS

    Directory of Open Access Journals (Sweden)

    D. V. Abramkina

    2017-01-01

    Full Text Available Objectives. The aim of the study is to analyse the effect of the design and methods for heating the ventilation duct of a buoyancy- driven system on the formation of free convective air currents in it.Methods. The study of free convection under the conditions of interior problem was carried out using the CFD software, based on  the finite volume method with unstructured grid. Ansys Fluent software was used as a calculation tool in the study, due to its having a high convergence of numerical solutions offering full-scale  measurements of convective currents.To evaluate the reliability of  the results obtained, a validation procedure was carried out, allowing us to determine how accurately the selected conceptual model describes the investigated flow through a comparison of experimental and numerical data.Results. The results of numerical modelling of free convective currents occurring in the heated channel of the ventilation system of  the top floor of a multi-storey residential building are presented in  the article. In the course of the study, the air velocity at the entrance to the ventilation duct was found to depend on the calculated  temperature difference θ ˚C for various heating methods. A gradual  increase in the discrepancy between the numerical simulation and  experimental results is observed if the calculated temperature  difference > 20 ° C. This phenomenon is due to the fact that with  increased duct temperature, it is quite difficult to achieve even  heating under actual conditions; this is especially noticeable when  considering the variant when the vertical part of the vent duct and the take-off are both heated. The maximum deviation of the  results is 4.4%. The obtained velocity profiles in the calculated  sections indicate the impact of the ventilation take-off on the nature  of the air flow motion.Conclusion. One of the drawbacks of the existing systems of natural ventilation of residential

  16. Ventilation System Type and the Resulting Classroom Temperature and Air Quality During Heating Season

    DEFF Research Database (Denmark)

    Gao, Jie; Wargocki, Pawel; Wang, Yi

    2014-01-01

    The present study investigated how different ventilation system types influence classroom temperature and air quality. Five classrooms were selected in the same school. They were ventilated by manually operable windows, manually operable windows with exhaust fan, automatically operable windows...... with and without exhaust fan and by mechanical ventilation system. Temperature, relative humidity, carbon dioxide (CO2) concentration and opening of windows were continuously monitored for one month during heating season in 2012. Classroom with manually operable windows had the highest carbon dioxide concentration...... levels so that the estimated ventilation rate was the lowest compared with the classrooms ventilated with other systems. Temperatures were slightly lower in classroom ventilated by manually operable windows with exhaust fan. Windows were opened seldom even in the classroom ventilated by manually operable...

  17. Technology Solutions Case Study: Ventilation System Effectiveness and Tested Indoor Air Quality Impacts

    Energy Technology Data Exchange (ETDEWEB)

    A. Rudd and D. Bergey

    2015-08-01

    Ventilation system effectiveness testing was conducted at two unoccupied, single-family, detached lab homes at the University of Texas - Tyler. Five ventilation system tests were conducted with various whole-building ventilation systems. Multizone fan pressurization testing characterized building and zone enclosure leakage. PFT testing showed multizone air change rates and interzonal airflow filtration. Indoor air recirculation by a central air distribution system can help improve the exhaust ventilation system by way of air mixing and filtration. In contrast, the supply and balanced ventilation systems showed that there is a significant benefit to drawing outside air from a known outside location, and filtering and distributing that air. Compared to the Exhaust systems, the CFIS and ERV systems showed better ventilation air distribution and lower concentrations of particulates, formaldehyde and other VOCs.

  18. Pressure Dynamic Characteristics of Pressure Controlled Ventilation System of a Lung Simulator

    Directory of Open Access Journals (Sweden)

    Yan Shi

    2014-01-01

    Full Text Available Mechanical ventilation is an important life support treatment of critically ill patients, and air pressure dynamics of human lung affect ventilation treatment effects. In this paper, in order to obtain the influences of seven key parameters of mechanical ventilation system on the pressure dynamics of human lung, firstly, mechanical ventilation system was considered as a pure pneumatic system, and then its mathematical model was set up. Furthermore, to verify the mathematical model, a prototype mechanical ventilation system of a lung simulator was proposed for experimental study. Last, simulation and experimental studies on the air flow dynamic of the mechanical ventilation system were done, and then the pressure dynamic characteristics of the mechanical system were obtained. The study can be referred to in the pulmonary diagnostics, treatment, and design of various medical devices or diagnostic systems.

  19. Building America Case Study: Ventilation System Effectiveness and Tested Indoor Air Quality Impacts, Tyler, Texas

    Energy Technology Data Exchange (ETDEWEB)

    2015-08-01

    ?Ventilation system effectiveness testing was conducted at two unoccupied, single-family, detached lab homes at the University of Texas - Tyler. Five ventilation system tests were conducted with various whole-building ventilation systems. Multizone fan pressurization testing characterized building and zone enclosure leakage. PFT testing showed multizone air change rates and interzonal airflow filtration. Indoor air recirculation by a central air distribution system can help improve the exhaust ventilation system by way of air mixing and filtration. In contrast, the supply and balanced ventilation systems showed that there is a significant benefit to drawing outside air from a known outside location, and filtering and distributing that air. Compared to the Exhaust systems, the CFIS and ERV systems showed better ventilation air distribution and lower concentrations of particulates, formaldehyde and other VOCs. System improvement percentages were estimated based on four System Factor Categories: Balance, Distribution, Outside Air Source, and Recirculation Filtration. Recommended System Factors could be applied to reduce ventilation fan airflow rates relative to ASHRAE Standard 62.2 to save energy and reduce moisture control risk in humid climates. HVAC energy savings were predicted to be 8-10%, or $50-$75/year. Cumulative particle counts for six particle sizes, and formaldehyde and other Top 20 VOC concentrations were measured in multiple zones. The testing showed that single-point exhaust ventilation was inferior as a whole-house ventilation strategy.

  20. [Sanitary and epidemiological evaluation of the ventilation and air-conditioning systems of public buildings].

    Science.gov (United States)

    Dvorianov, V V

    2012-01-01

    The microbial contamination of ventilation and air conditioning systems was examined in the administrative buildings. The author proposes a set of indicators, methods for determining the scope of investigations, as well as sampling tactics and criteria for evaluating the microbial contamination of the ventilation and air-conditioning systems. The content of yeasts and molds in the delivered air has been found to be of importance for evaluating the sanitary-and epidemiological state of ventilation systems.

  1. Design of laser diode stable output system

    Science.gov (United States)

    Liu, Bo; Cao, Rui-ming

    2008-03-01

    High-stability output's system of laser diode is introduced in this paper. The system which is based on the MCU of MSP430 has been designed light power feedback loop and coller of TEC. It includes stable current, protecting circuit, light power feedback loop, temperature controlling, power display and so on. It is also able to control and show the power at the real time. The power could be set by botton too. The software of slow start up, slow close and the protecting relay are adopted by MCU. DRV592 is introduced as PWM driver to control the current of TEC. The duty cycle is generate by MCU. In order to control temperature, it is changed to influence the current of TEC. The power that is sampled by photodiode which is integrated in the laser diode is controlled by the micro-processing. The laser is monitored by voltage control circuit and current control circuit at the real time.

  2. Ventilation systems for multi-unit residential buildings : performance requirements and alternative approaches

    Energy Technology Data Exchange (ETDEWEB)

    Hill, D.

    2003-09-01

    A growing proportion of housing in Canada consists of multi-unit residential buildings (MURBs). Ventilation strategies have not changed much over the past three decades. Research conducted by Canada Mortgage and Housing Corporation (CMHC) and others has shown that conventional ventilation strategies consume significant amounts of energy, are noisy, consume internal floor area, and can become conduits for pests and smoke. As a result, a research project was initiated to develop performance requirements and alternative approaches for ventilation systems in MURBs. The issues to be addressed by alternative ventilation systems were identified through literature review. The various codes and standards applicable to ventilation capacities for apartments in MURBs in Canada were evaluated. It was revealed that the ventilation system airflow rates required for any given apartment and the amount of ventilation that should be provided by infiltration varies greatly depending on the codes or standards selected. The performance parameters that were identified in this paper were: ventilation performance, capital and operating costs, maintenance, fire and smoke control, noise issues, comfort, system issues, and owner and designer construction issues. The following four different alternative ventilation systems were discussed: (1) passive vents with suite-based mechanical exhaust, (2) balanced individual suites with heat recovery (HRV) units, (3) balanced floor-by-floor systems with heat recovery, and (4) balanced central systems with heat recovery. Further testing and assessment is needed before these proposed systems can enter the marketable phase. More research is also needed into the characterization of stack and wind pressures in MURBs. 5 tabs.

  3. Control Strategies to Conserve Energy in All-Air Heating Ventilation and Air Conditioning Systems.

    Science.gov (United States)

    1979-05-14

    York, ASHRAE, Inc. American Society of Heating, Refrigerating and Air- Conditioning Engineers. "Standards for Natural and Mechanical Ventilation ...or REPoRT a P61mO0 COVERED 1 Control Strategies to Conserve Energy in All-Air Heating Ventilation and Air Conditioning THESIS 14Systems o ~~~sGOG...Morrison, William James (M. S., Civil Engineering) Control Strategies to Conserve Energy in All-Air Heating Ventilation and Air Conditioning Systems Report

  4. An overview of the TA-55, Building PF-4 ventilation system

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1994-02-22

    An overview of the TA-55, Building PF-4 ventilation system is provided in the following sections. Included are descriptions of the zone configurations, equipment-performance criteria, ventilation support systems, and the ventilation-system evaluation criteria. Section 4.2.1.1 provides a brief discussion of the ventilation system function. Section 4.2.1.2 provides details on the overall system configuration. Details of system interfaces and support systems are provided in Section 4.2.1.3. Section 4.2.1.4 describes instrumentation and control needed to operate the ventilation system. Finally, Sections 4.2.1.5 and 4.2.1.6 describe system surveillance/maintenance and Technical Safety Requirements (TSR) Limitations, respectively. Note that the numerical parameters included in this description are considered nominal; set points and other specifications actually fall within operational bands.

  5. Real-time evaluation of ventilation filter-bank systems.

    Science.gov (United States)

    Moyer, Ernest S; Commodore, Michael A; Hayes, Jeffrey L; Fotta, Steven A; Berardinelli, Stephen P

    2007-01-01

    This study evaluated two government facility ventilation systems. One was a metropolitan government office complex with a recirculation system where outside air was the makeup air; the other was a NIOSH facility that used 100% outside air with no recirculation. The methodology employed was a modified American Society of Agricultural Engineers standard (S525) for testing total enclosure filtration efficiency, in agricultural tractor cabs, with optical particle counters (OPC). The low-efficiency bag filters were tested when new and after being in the ventilation system for 3 months. The replacement medium-efficiency filters were evaluated for 6 months (the manufacturer's suggested change-out schedule). These eight-chamber, medium-efficiency filters had an increased filter surface area that resulted in increased airflow through the system. Unfortunately, these filters contained electrostatic filter media and lost filtration efficiency rapidly, which was subsequently confirmed in a 30-day study conducted to determine an appropriate change-out schedule for the eight-chamber bag filters. The study determined that less than 6 months' use was justified due to the reduced efficiency of the electrostatic filter media. The NIOSH facility's air handler #8 (100% outside air unit) was upgraded from electrostatic bag filters, which had a suggested 9-month change-out schedule, to V Bank mechanical, wet-laid, glass fiber filters. The results of a 3-year evaluation showed that the V Bank filters had better filter efficiency after 3 years of service than the electrostatic filters had at 9 months. Both studies employed matched OPC instruments to reduce instrument-to-instrument bias. The methodology is adaptable to monitoring the total efficiency of most air filtration systems, and results can help make decisions about upgrading filter performance.

  6. Applied patent RFID systems for building reacting HEPA air ventilation system in hospital operation rooms.

    Science.gov (United States)

    Lin, Jesun; Pai, Jar-Yuan; Chen, Chih-Cheng

    2012-12-01

    RFID technology, an automatic identification and data capture technology to provide identification, tracing, security and so on, was widely applied to healthcare industry in these years. Employing HEPA ventilation system in hospital is a way to ensure healthful indoor air quality to protect patients and healthcare workers against hospital-acquired infections. However, the system consumes lots of electricity which cost a lot. This study aims to apply the RFID technology to offer a unique medical staff and patient identification, and reacting HEPA air ventilation system in order to reduce the cost, save energy and prevent the prevalence of hospital-acquired infection. The system, reacting HEPA air ventilation system, contains RFID tags (for medical staffs and patients), sensor, and reacting system which receives the information regarding the number of medical staff and the status of the surgery, and controls the air volume of the HEPA air ventilation system accordingly. A pilot program was carried out in a unit of operation rooms of a medical center with 1,500 beds located in central Taiwan from Jan to Aug 2010. The results found the air ventilation system was able to function much more efficiently with less energy consumed. Furthermore, the indoor air quality could still keep qualified and hospital-acquired infection or other occupational diseases could be prevented.

  7. [Controlled mechanical lung ventilation with guaranteed volume in newborns].

    Science.gov (United States)

    Kriakvina, O A; Grebennikov, V A; Tsypin, L E; Volodin, N N

    2011-01-01

    Mechanical ventilation with guaranteed volumes combines advantages of time-cyclic ventilation with limitation of pressure and constant flow, with volume control ventilation. This symbiosis allows to choose the optimal, stable breathing volume of the newborn, while maintaining pressure control. The review presents the principles of work, the main advantages and limitations of ventilation systems with the guaranteed volumes, as well as results and analysis of studies.

  8. Modifications of tissular oxygenation and systemic hemodynamics after the correction of hypocapnia induced by mechanical ventilation.

    Science.gov (United States)

    Boix, J H; Marin, J; Enrique, E; Monferrer, J; Bataller, A; Servera, E

    1994-03-01

    The modifications of systemic hemodynamics, oxygen transport and tissular oxygenation in mechanically-ventilated critical ARF (acute respiratory failure) patients, after the correction of its hypocapnia by addition of dead space (VD) are determined. The prospective and randomized study was carried out in a multidisciplinary ICU. Fifteen ARF patients were studied within the first 48 hours of evolution. All the patients were intubated and mechanically ventilated. Three stages were delimited: I) 30 min after the beginning of anesthesia; II) 30 min after adding 30 cm of VD; III) 30 min after replacing the previous VD with a VD of 60 cm. Similar steady states had been reached when the measurements were taken. Ventilation parameters and FiO2 were kept stable. In stage I the patients presented a pure respiratory alkalosis and, with respect to hemodynamics, a hyperdynamic situation. In stage II the acid-base balance was normalized with a continuation of the hyperdynamic situation and an increase in mixed venous oxygen tension and saturation (PvO2 and SvO2) (p < 0.001). Stage III was characterized by a pure hypercapnic acidosis and an increase in capillary wedge pressure (CWP) (p < 0.05), right atrial pressure (RAP) (p < 0.001) and cardiac output (Qt) (p < 0.001); simultaneously, the systemic vascular resistances (SVR) decreased (p < 0.01), the PvO2, SvO2 and oxygen delivery (DO2) increased (p < 0.001); oxygen utilization coefficient (OUC) decreased (p < 0.01). The results suggest that the variations in PvO2 and SvO2 are a direct consequence of the modifications in blood flow.(ABSTRACT TRUNCATED AT 250 WORDS)

  9. Stability properties of nonlinear dynamical systems and evolutionary stable states

    Energy Technology Data Exchange (ETDEWEB)

    Gleria, Iram, E-mail: iram@fis.ufal.br [Instituto de Física, Universidade Federal de Alagoas, 57072-970 Maceió-AL (Brazil); Brenig, Leon [Faculté des Sciences, Université Libre de Bruxelles, 1050 Brussels (Belgium); Rocha Filho, Tarcísio M.; Figueiredo, Annibal [Instituto de Física and International Center for Condensed Matter Physics, Universidade de Brasília, 70919-970 Brasília-DF (Brazil)

    2017-03-18

    Highlights: • We address the problem of equilibrium stability in a general class of non-linear systems. • We link Evolutionary Stable States (ESS) to stable fixed points of square quasi-polynomial (QP) systems. • We show that an interior ES point may be related to stable interior fixed points of QP systems. - Abstract: In this paper we address the problem of stability in a general class of non-linear systems. We establish a link between the concepts of asymptotic stable interior fixed points of square Quasi-Polynomial systems and evolutionary stable states, a property of some payoff matrices arising from evolutionary games.

  10. Analysis of the systems of ventilation of residential houses of Ukraine and Estonia

    Science.gov (United States)

    Savchenko, Olena; Zhelykh, Vasyl; Voll, Hendrik

    2017-12-01

    The most common ventilation system in residential buildings in Ukraine is natural ventilation. In recent years, due to increased tightness of structures, an increase in the content of synthetic finishing materials in them, the quality of microclimate parameters deteriorated. One of the measures to improve the parameters of indoor air in residential buildings is the use of mechanical inflow and exhaust ventilation system. In this article the regulatory documents concerning the design of ventilation systems in Ukraine and Estonia and the requirements for air exchange in residential buildings are considered. It is established that the existing normative documents in Ukraine are analogous to European norms, which allow design the system of ventilation of residential buildings according to European standards. However, the basis for the design of ventilation systems in Ukraine is the national standards, in which mechanical ventilation, unfortunately, is provided only for the design of high-rise buildings. To maintain acceptable microclimate parameters in residential buildings, it is advisable for designers to apply the requirements for designing ventilation systems in accordance with European standards.

  11. Computer-simulation study on fire behaviour in the ventilated cavity of ventilated façade systems

    Directory of Open Access Journals (Sweden)

    Giraldo María P.

    2013-11-01

    Full Text Available Fire spread through the façades is widely recognized as one of the fastest pathways of fire spreading in the buildings. Fire may spread through the façade in different ways depending on the type of façade system and on the elements and materials from which it is constructed. Ventilated façades are multilayer systems whose main feature is the creation of an air chamber of circulating air between the original building wall and the external cladding. The “chimney effect” in the air cavity is a mechanism that improves the façade's thermal behaviour and avoids the appearance of moisture from rain or condensation. However, in a event of fire, it may contribute to the quickest spreading of fire, representing a significant risk to the upper floors of a building. This study deals with some aspects of fire propagation through the ventilated cavity in ventilated façade systems. Also we review the provisions stipulated by the Spanish building code (Código Técnico de la Edificación, CTE [1] to avoid fire spread outside the building. The results highlight the importance of the use of proper fire barriers to ensure the compartmentalization of the ventilated cavity, as well as the use of non-combustible thermal insulation materials, among others. In addition, based on the results, it might be considered that the measures stipulated by the CTE are insufficient to limit the risks associated with this kind of façades systems. The study has been performed using field models of computational fluid-dynamics. In particular, the Fire Dynamics Simulator (FDS software has been used to numerically solve the mathematical integration models.

  12. Stable light isotope biogeochemistry of hydrothermal systems.

    Science.gov (United States)

    Des Marais, D J

    1996-01-01

    The stable isotopic composition of the elements O, H, S and C in minerals and other chemical species can indicate the existence, extent, conditions and the processes (including biological activity) of hydrothermal systems. Hydrothermal alteration of the 18O/16O and D/H values of minerals can be used to detect fossil systems and delineate their areal extent. Water-rock interactions create isotopic signatures which indicate fluid composition, temperature, water-rock ratios, etc. The 18O/16O values of silica and carbonate deposits tend to increase with declining temperature and thus help to map thermal gradients. Measurements of D/H values can help to decipher the origin(s) of hydrothermal fluids. The 34S/32S and 13C/12C values of fluids and minerals reflect the origin of the S and C as well as oxygen fugacities and key redox processes. For example, a wide range of 34S/32S values which are consistent with equilibration below 100 degrees C between sulfide and sulfate can be attributed to sulfur metabolizing bacteria. Depending on its magnitude, the difference in the 13C/12C value of CO2 and carbonates versus organic carbon might be attributed either to equilibrium at hydrothermal temperatures or, if the difference exceeds 1% (10/1000), to organic biosynthesis. Along the thermal gradients of thermal spring outflows, the 13C/12C value of carbonates and 13C-depleted microbial organic carbon increases, principally due to the outgassing of relatively 13C-depleted CO2.

  13. FAST FLUX TEST FACILITY CONCEPTUAL SYSTEM DESIGN DESCRIPTION FOR THE HEATING AND VENTILATION SYSTEM NO. 25

    Energy Technology Data Exchange (ETDEWEB)

    None

    1969-12-05

    The Heating and Ventilation System provides the atmospheric conditions in FFTF as required to assure that plant objectives can be met in a safe and practical manner. Included are functions and design requirements, a physical description of the system, safety considerations, principles of operation, and maintenance principles.

  14. Energy analysis of the personalized ventilation system in hot and humid climates

    DEFF Research Database (Denmark)

    Schiavon, S.; Melikov, Arsen Krikor; Sekhar, C.

    2010-01-01

    Personalized ventilation (PV) is an individually controlled air distribution system aimed at improving the quality of inhaled air and the thermal comfort of each occupant. Numerous studies have shown that PV in comparison with traditional mechanical ventilation systems may improve occupants’ health......, inhaled air quality, thermal comfort, and self-estimated productivity. Little is known about its energy performance. In this study, the energy consumption of a personalized ventilation system introduced in an office building located in a hot and humid climate (Singapore) has been investigated by means...... of simulations with the empirically tested IDA-ICE software. The results reveal that the use of PV may reduce the energy consumption substantially (up to 51%) compared to mixing ventilation when the following control strategies are applied: (a) reducing the airflow rate due to the higher ventilation...

  15. Performance analysis of a new design of office diffuse ceiling ventilation system

    DEFF Research Database (Denmark)

    Fan, Jianhua; Hviid, Christian Anker; Yang, Honglu

    2013-01-01

    This paper aims to document and analyse performance of a new design of diffuse ceiling ventilation system in a typical office room. A full scale measurement is carried out in a climate chamber with an office setup at the Technical University of Denmark. Indoor air temperatures, air speeds, wall...... surface temperatures, pressure loss of the ceiling and ventilation effectiveness are measured for an air change rate of 3.5 h-1 and 5.1 h -1 respectively. A computational fluid dynamics model of the office with the diffuse ceiling ventilation system is built and validated by the full scale measurement....... The measurements of pressure loss across the ceiling show a low pressure drop between the plenum and the occupied zone. Ventilation effectiveness is measured to be close to 1 on average under the tested conditions. It is shown that the diffuse ceiling ventilation system is able to remove indoor pollutant...

  16. Passive ventilation systems with heat recovery and night cooling

    DEFF Research Database (Denmark)

    Hviid, Christian Anker; Svendsen, Svend

    2008-01-01

    In building design the requirements for energy consumption for ventilation, heating and cooling and the requirements for increasingly better indoor climate are two opposing factors. This paper presents the schematic layout and simulation results of an innovative multifunc-tional ventilation concept...... with little energy consumption and with satisfying indoor climate. The concept is based on using passive measures like stack and wind driven ventilation, effective night cooling and low pressure loss heat recovery using two fluid coupled water-to-air heat exchangers developed at the Technical University...

  17. An Evaluation of a Proposed Ventilation System for Melbourne's CH2 Building

    Directory of Open Access Journals (Sweden)

    Lu Aye

    2012-11-01

    Full Text Available The understanding of ventilation requirements in commercial buildings has been significantly revised in the last 10-15 years. A link between health, productivity and increased fresh air use has been established by some research and this understanding underpins the ventilation philosophy adopted for the CH2 building. The ventilation system design for CH2 that has been evaluated in this paper envisages a mechanically driven system during the day, using the displacement technique to distribute filtered air. All introduced air will be drawn from outside and no recycling of air will occur. Natural ventilation will be employed at night using the stack effect, enhanced by turbine ventilators. This paper critiques the proposed ventilation system in the light of international experience and the particular conditions of the building's location. The evidence suggests that natural ventilation sometimes may be inadequate to achieve the desired objectives. Minimization of indoor pollutants, adequate filtration and high levels of ventilation should, however, ensure satisfactory air quality during occupied hours.

  18. Noxious gases in rabbit housing systems: effects of cross and longitudinal ventilation

    Directory of Open Access Journals (Sweden)

    Francesco da Borso

    2016-12-01

    Full Text Available Animal welfare is a matter of increasing interest due to ethical and economical worries regarding animal rights and the sustainability of meat production. Ammonia, carbon dioxide, and methane can be produced in the livestock buildings and, if not adequately controlled by ventilation, can be dangerous for animals and farmers. The aim of the present paper is to study the effects of different ventilation systems in rabbit buildings based on the temporal patterns and the spatial distribution of these noxious gases. The experimental measurements were conducted in two rabbit farms with genetically homogeneous animals subjected to the same diet. Two buildings with different forced ventilation layouts (cross ventilation - building A and longitudinal ventilation - building B were subjected to the monitoring of indoor environmental conditions (temperature, relative humidity, ammonia, carbon dioxide, methane over a whole year. In both the buildings, ventilation was adjusted automatically by means of electronic control units, which were controlled by temperature sensors, located at the centre of the buildings. Gas concentrations inside the buildings followed clearly defined sinusoidal patterns on a daily basis with the highest values reached in winter during the morning hours for ammonia and during the night hours for carbon dioxide and methane. In particular, ammonia revealed a maximum concentration of 30.7 mg m–3 in building A (cross ventilation and 12.9 mg m–3 in building B (longitudinal ventilation, whereas the minimum values were 6.0 and 4.2 mg m–3, in building A and B, respectively. As a consequence, daily mean concentrations of noxious gases, solely could not be considered representative of the actual conditions of air quality in the buildings. The airflow direction clearly influenced the spatial concentration of ammonia, which showed different patterns in the two buildings. In building A, the highest ammonia concentration was in a diffuse

  19. TVENT: a computer program for analysis of tornado-induced transients in ventilation systems. [TVENT

    Energy Technology Data Exchange (ETDEWEB)

    Duerre, K.H.; Andrae, R.W.; Gregory, W.S.

    1978-07-01

    The report describes TVENT, a portable FORTRAN computer program for predicting flows and pressures in a ventilation system subject to a tornado. The pressure and flow values calculated by TVENT can be used as a basis for structural analysis. TVENT is a one-dimensional, lumped-parameter model with incompressible flow augmented by fluid storage. The theoretical basis for the mathematical modeling and analysis is presented, and a description of the input for the computer code is provided. Modeling techniques specific to ventilation systems are described. Sample problems illustrate the use of TVENT in analyzing ventilation systems. Other sample problems illustrate modeling techniques used in reducing complex systems.

  20. A Bayesian decision-support system for diagnosing ventilator-associated pneumonia

    NARCIS (Netherlands)

    Schurink, C.A.; Visscher, S.; Lucas, P.J.; van Leeuwen, H.J.; Buskens, E.; Hoff, R.G.; Hoepelman, A.I.; Bonten, M.J.

    2007-01-01

    OBJECTIVE: To determine the diagnostic performance of a Bayesian Decision-Support System (BDSS) for ventilator-associated pneumonia (VAP). DESIGN: A previously developed BDSS, automatically obtaining patient data from patient information systems, provides likelihood predictions of VAP. In a

  1. Power Efficiency of Systems Applied for Heating Building and Structure External Walls with Ventilated Air Spaces

    OpenAIRE

    I. F. Fialko; A. S. Statsenko

    2009-01-01

    The paper considers power-efficient systems applied for heating building and structure external walls with ventilated air spaces and prescribes directions and problems pertaining to power-efficiency improvement of such systems.

  2. Computational study of smoke flow control in garage fires and optimization of the ventilation system

    Directory of Open Access Journals (Sweden)

    Banjac Miloš J.

    2009-01-01

    Full Text Available With the aim of evaluating capabilities of a ventilation system to control the spread of smoke in the emergency operating mode, thereby providing conditions for safe evacuation of people from a fire-struck area, computational fluid dynamics simulation of a fire in a semi-bedded garage was conducted. Using the experimental results of combustion dynamics of a passenger car on fire, optimal positions of ventilation openings were determined. According to recommendations by DIN EN 12101 standard, the operating modes of a ventilation system were verified and optimal start time of the smoke extraction system was defined.

  3. Ventilation system type, classroom environmental quality and pupils' perceptions and symptoms

    DEFF Research Database (Denmark)

    Gao, Jie; Wargocki, Pawel; Wang, Yi

    2014-01-01

    The present study investigated indoor climate and window opening behaviour by pupils, as well as their perceptions and symptoms in classrooms with different types of ventilation systems. Four classrooms were selected in the same school in suburban Denmark. Classroom ventilation was achieved either......-heating and heating seasons; CO2 concentration was used to estimate average classroom ventilation rates. At the end of each measuring period, the pupils were asked to report their perceptions of the indoor environment and their acute health-related symptoms. The classroom in which ventilation was achieved by manually...... operable windows had the highest air temperatures and CO2 concentrations during both non-heating and heating season; the estimated average air-change rate was lowest in this classroom. The classroom with mechanical ventilation had the highest estimated average air-change rate. Windows were frequently...

  4. Upgrade of a transverse ventilation system in a bi-directional tunnel

    Directory of Open Access Journals (Sweden)

    Vidmar Peter

    2012-01-01

    Full Text Available The Karavanke tunnel forms an important link between Slovenia and Austria. The almost 8 km long tunnel is operated with bi-directional traffic and does not have dedicated escape routes. Moreover, the ventilation in case of fire does not satisfy requirements of the EU Directive 2004/54/EC that specifies the minimum requirements for tunnels in the trans-European road network. The paper present results of the research conducted regarding the possibility of upgrade the existing system in order to reach the required level of safety at lower costs possible. It is shown that with simple but novel adaptations of the ventilation system, a sizeable increase in the overall level of safety can be achieved. The methodology applied is a combination of a simple pipe model for tunnel ventilation and for detailed fluid dynamics analysis the CFD model is used. The existing ventilation system that in fire ventilation extracts smoke from a single duct is replaced with the smoke extraction from both ducts applying four axial fans. The analysis is focused on air/smoke flow through the vents and ducts and on pressure drops calculated over the length of the ventilation duct and its influence on the total flow. The change of the flow condition also has influence on ventilation fan operation point that is investigated in the paper as well.

  5. Association of ventilation system type with SBS symptoms in office workers

    Energy Technology Data Exchange (ETDEWEB)

    Seppanen, Olli; Fisk, William J.

    2001-02-07

    This paper provides a review and synthesis of current knowledge about the associations of ventilation system types in office buildings with sick building syndrome symptoms and discusses potential explanations for the associations. Relative to natural ventilation, air conditioning, with or without humidification, was consistently associated with a statistically significant increase in the prevalence of one or more SBS symptoms. Prevalences were typically higher by approximately 30% to 200% in the air conditioned buildings. In two of three assessments from a single study, symptom prevalences were also significantly higher in air conditioned buildings than in buildings with simple mechanical ventilation and no humidification. In approximately half of assessments, SBS symptom prevalences were significantly higher in buildings with simple mechanical ventilation than in buildings with natural ventilation. Insufficient information was available for conclusions about the potential increased risk of SBS symptoms with humidification. The statistically significant associations of mechanical ventilation and air conditioning with SBS symptoms are much more frequent than expected from chance and also not likely to be a consequence of confounding by several potential personal, job, or building related confounders. The reasons for the increases in symptom prevalences with mechanical ventilation and particularly with air conditioning remain unclear. Multiple deficiencies in HVAC system design, construction, operation, or maintenance, including some which cause pollutant emissions from HVAC systems, may contribute to the increases in symptom prevalences.

  6. Use of VOC sensors for air quality control of building ventilation systems

    National Research Council Canada - National Science Library

    M Großklos

    2015-01-01

    .... An air quality control was developed and tested in four single-family passive house dwellings to control the building ventilation system via VOC sensors and a special adaptation algorithm to handle...

  7. Stability properties of nonlinear dynamical systems and evolutionary stable states

    Science.gov (United States)

    Gleria, Iram; Brenig, Leon; Rocha Filho, Tarcísio M.; Figueiredo, Annibal

    2017-03-01

    In this paper we address the problem of stability in a general class of non-linear systems. We establish a link between the concepts of asymptotic stable interior fixed points of square Quasi-Polynomial systems and evolutionary stable states, a property of some payoff matrices arising from evolutionary games.

  8. In vitro growth and leaf anatomy of Cattleya walkeriana (Gardner, 1839 grown in natural ventilation system

    Directory of Open Access Journals (Sweden)

    Adriano Bortolotti da Silva

    2014-12-01

    Full Text Available Natural ventilation system facilitates gaseous exchanges in in vitro plants promoting changes in the leaf tissue, which can be evaluated through the leaf anatomy, and it allows a cultivation closer to the photoautrophic micropropagation. The objective of this work was to evaluate the effects on in vitro growth and on the leaf anatomy of Cattleya walkeriana grown in natural and conventional ventilation system with different concentrations of sucrose (0; 15; 30 and 45 L-1 combined with different cultivation systems (conventional micropropagation and natural ventilation system. The culture medium was composed of MS salts, solidified with 7 g L-1 of agar and pH adjusted to 5.8. Forty milliliters of culture medium were distributed in 250 mL flasks, autoclaved at 120 ºC for 20 minutes. The greater plant growth, as well as the greater thickness of the mesophyll was observed with the use of 20 g L-1 sucrose in natural ventilation system. Plants grown in natural ventilation system showed a thicker leaf mesophyll, which is directly related to photoautotrophic crops. The natural ventilation system induced more elliptical stomata and probably more functional formats.

  9. Housing and natural ventilation. Indoor climate, energy, reliability; Bolig og naturlig ventilation: indeklima energi driftssikkerhed

    Energy Technology Data Exchange (ETDEWEB)

    Marsh, R.; Lauring, M. (eds.)

    2003-07-01

    The aim of this book is to show how natural ventilation can be used successfully in housing. Housing ventilation aims at balancing complex and often diametrically opposed demands. This book examines the complexity with different quantitative and qualitative approaches. In the first chapter, History, the Danish housing ventilation from 1850-2002 is examined. The requirements for natural ventilation have developed historically, based upon a spatial organisation with fresh air supply to the less polluted rooms and stack effect removal from the more polluted rooms. A series of important factors relating to a healthy indoor climate, energy savings and demands for functional stability have affected this development. In the second chapter, Models, a series of architectural models for natural ventilated large building types are analysed. There has for many years been much R and D activity aimed at using natural ventilation in large buildings. Much of the knowledge about the requirements for natural ventilation (spatial organisation, fresh air supply and stack effect removal) can therefore be used in the development of naturally ventilated housing. The third chapter, Principles, develops a set of principles for naturally ventilated housing by examining the requirements relating to spatial organisation, fresh air supply, and stack effect removal. By optimizing the architectural and technical design of a typical terraced house, the three aims for the successful use of natural ventilation in housing can be achieved; a very low energy consumption and environmental impact, a healthy indoor climate and a functionally stable ventilation system. The fourth chapter, Houses, presents architectural designs for a series of naturally ventilated terraced houses. The designs focus on the use of spatial organisation, fresh air supply and stack removal to optimize the natural ventilation. Architecture and technology are integrated in the design to achieve low energy consumption, a healthy

  10. Project W-320 high vacuum 241-AY-102 annulus ventilation system operability test report

    Energy Technology Data Exchange (ETDEWEB)

    Bailey, J.W.

    1998-03-12

    This report documents the test results of OTP-320-001, Tank 241-AY-102 Annulus Ventilation System Testing. Included in the appendices are: (1) Supporting documentation prepared to demonstrate the structural integrity of the tank at high annulus vacuum (<20 INWG), and (2) a report that identifies potential cross connections between the primary and annulus ventilation systems. These cross connections were verified to be eliminated prior to the start of testing.

  11. Study on pollution control in residential kitchen based on the push-pull ventilation system

    DEFF Research Database (Denmark)

    Zhou, Bin; Chen, Feng; Dong, Zhibo

    2016-01-01

    Highlights •The push-pull ventilation system is proposed to improve IAQ inside kitchen, where air is supplied through slot air curtain and then exhausted through range hood. •CO2 reduction efficiency with application of air curtain in experiment and simulation in breathing zone was 23.7% and 23.......1%, respectively. •By orthogonal method, the influence of factors on pollution control of the push-pull ventilation system was presented....

  12. Indoor temperatures for calculating room heat loss and heating capacity of radiant heating systems combined with mechanical ventilation systems

    DEFF Research Database (Denmark)

    Wu, Xiaozhou; Olesen, Bjarne W.; Fang, Lei

    2016-01-01

    In this study, a typical office room with a radiant heating system and a mechanical ventilation system was selected as the research subject. Indoor temperature formulas for calculating the room heat loss (including transmission heat loss and ventilation heat loss) and heating capacity of the hybrid...... for calculating ventilation heat loss and heating capacity of radiant heating systems combined with mechanical ventilation systems. (C) 2015 Elsevier B.V. All rights reserved....... change rates on the indoor temperatures were performed using the proposed model. When heated surface temperatures and air change rates were from 21.0 to 29.0 degrees C and from 0.5 to 4.0 h-1, the indoor temperatures for calculating the transmission heat loss and ventilation heat loss were between 20...

  13. A novel system solution for cooling and ventilation in office buildings

    DEFF Research Database (Denmark)

    Yu, Tao; Heiselberg, Per Kvols; Lei, Bo

    2015-01-01

    technologies and renewable energy sources have risen. Based on a literature review of natural ventilation, building thermal mass activation and diffuse ceiling ventilation, this paper proposes a new system solution combining these three technologies for cooling and ventilation in office buildings. This new......As a response to new energy policies in the building sector, office buildings have become well-insulated and highly-airtight, resulting in an increasing cooling need both in summer and in winter. In order to effectively save energy, new interests in cooling concepts using passive cooling...

  14. Use of perforated acoustic panels as supply air diffusers in diffuse ceiling ventilation systems

    DEFF Research Database (Denmark)

    Iqbal, Ahsan; Kazemi, Seyed Hossein; Ardkapan, Siamak Rahimi

    Ventilation is needed for diluting and removing the contaminants, odour and excess heat from the building interior. It is important that the inhabitants perceive the ventilated spaces as comfortable. Therefore, the supply air should reach all parts of the occupied zones. Troldtekt has been...... manufacturing perforated acoustic panels for the last 13 years. The panels can be used not only in applications related to acoustics but also as low pressure drop supply air diffusers, particularly in diffuse ceiling ventilation systems. The present study verifies on a theoretically level the performance...

  15. Change-over natural and mechanical ventilation system energy consumption in single-family buildings

    Science.gov (United States)

    Kostka, Maria; Szulgowska-Zgrzywa, Małgorzata

    2017-11-01

    The parameters of the outside air in Poland cause that in winter it is reasonable to use a mechanical ventilation equipped with a heat recovery exchanger. The time of spring, autumn, summer evenings and nights are often characterized by the parameters of the air, which allow for a natural ventilation and reduce the electricity consumption. The article presents the possibilities of energy consumption reduction for three energy standards of buildings located in Poland, ventilated by a change-over hybrid system. The analysis was prepared on the assumption that the air-to-water heat pump is the heat source for the buildings.

  16. Control system design for a continuous positive airway pressure ventilator

    Directory of Open Access Journals (Sweden)

    Chen Zheng-Long

    2012-02-01

    Full Text Available Abstract Continuous Positive Airway Pressure (CPAP ventilation remains a mainstay treatment for obstructive sleep apnea syndrome (OSAS. Good pressure stability and pressure reduction during exhalation are of major importance to ensure clinical efficacy and comfort of CPAP therapy. In this study an experimental CPAP ventilator was constructed using an application-specific CPAP blower/motor assembly and a microprocessor. To minimize pressure variations caused by spontaneous breathing as well as the uncomfortable feeling of exhaling against positive pressure, we developed a composite control approach including the feed forward compensator and feedback proportional-integral-derivative (PID compensator to regulate the pressure delivered to OSAS patients. The Ziegler and Nichols method was used to tune PID controller parameters. And then we used a gas flow analyzer (VT PLUS HF to test pressure curves, flow curves and pressure-volume loops for the proposed CPAP ventilator. The results showed that it met technical criteria for sleep apnea breathing therapy equipment. Finally, the study made a quantitative comparison of pressure stability between the experimental CPAP ventilator and commercially available CPAP devices.

  17. Measuring Residential Ventilation System Airflows: Part 1 – Laboratory Evaluation of Airflow Meter Devices

    Energy Technology Data Exchange (ETDEWEB)

    Stratton, J. Chris [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Environmental Energy Technologies Division; Turner, W. J. N. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Environmental Energy Technologies Division; Wray, Craig P. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Environmental Energy Technologies Division; Walker, Iain S. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Environmental Energy Technologies Division

    2012-11-12

    Building codes increasingly require tighter homes and mechanical ventilation per ASHRAE Standard 62.2. These ventilation flows must be measured so that energy is not wasted with over ventilation and occupants’ health is not compromised by under ventilation. Flow hoods are used to measure these ventilation flows, but there is currently no standard specifying the measurement procedure and measurement devices that should be used. This study evaluates the accuracy of six commercially available flow hoods under laboratory conditions configured to emulate a residential mechanical ventilation duct system. The measurements taken with the flow hoods were compared to simultaneous measurements taken by an in-line reference flow meter having a known uncertainty. Results indicate that powered flow hoods yield more accurate measurements than non-powered flow hoods, and that a majority of the flow hoods measured inlet flows more accurately than outlet flows. In several cases, there was little resemblance between the manufacturers’ stated accuracy and the accuracy we found in our laboratory measurements. It is clear that current flow hood calibration procedures may not consider field application variables such as flow asymmetry, flow angle, and flow direction. A new flow hood measurement standard that takes these ‘real world’ conditions into account should be developed to ensure that residential buildings receive the intended ventilation flows.

  18. Measuring Residential Ventilation System Airflows: Part 1 – Laboratory Evaluation of Airflow Meter Devices

    Energy Technology Data Exchange (ETDEWEB)

    Stratton, J. Chris [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Environmental Energy Technologies Division; Turner, W. J. N. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Environmental Energy Technologies Division; Wray, Craig P. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Environmental Energy Technologies Division; Walker, Iain S. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Environmental Energy Technologies Division

    2012-11-30

    Building codes increasingly require tighter homes and mechanical ventilation per ASHRAE Standard 62.2. These ventilation flows must be measured so that energy is not wasted with over ventilation and occupants’ health is not compromised by under ventilation. Flow hoods are used to measure these ventilation flows, but there is currently no standard specifying the measurement procedure and measurement devices that should be used. This study evaluates the accuracy of six commercially available flow hoods under laboratory conditions configured to emulate a residential mechanical ventilation duct system. The measurements taken with the flow hoods were compared to simultaneous measurements taken by an in-line reference flow meter having a known uncertainty. Results indicate that powered flow hoods yield more accurate measurements than non-powered flow hoods, and that a majority of the flow hoods measured inlet flows more accurately than outlet flows. In several cases, there was little resemblance between the manufacturers’ stated accuracy and the accuracy we found in our laboratory measurements. It is clear that current flow hood calibration procedures may not consider field application variables such as flow asymmetry, flow angle, and flow direction. A new flow hood measurement standard that takes these ‘real world’ conditions into account should be developed to ensure that residential buildings receive the intended ventilation flows.

  19. A new system for continuous and remote monitoring of patients receiving home mechanical ventilation

    Science.gov (United States)

    Battista, L.

    2016-09-01

    Home mechanical ventilation is the treatment of patients with respiratory failure or insufficiency by means of a mechanical ventilator at a patient's home. In order to allow remote patient monitoring, several tele-monitoring systems have been introduced in the last few years. However, most of them usually do not allow real-time services, as they have their own proprietary communication protocol implemented and some ventilation parameters are not always measured. Moreover, they monitor only some breaths during the whole day, despite the fact that a patient's respiratory state may change continuously during the day. In order to reduce the above drawbacks, this work reports the development of a novel remote monitoring system for long-term, home-based ventilation therapy; the proposed system allows for continuous monitoring of the main physical quantities involved during home-care ventilation (e.g., differential pressure, volume, and air flow rate) and is developed in order to allow observations of different remote therapy units located in different places of a city, region, or country. The developed remote patient monitoring system is able to detect various clinical events (e.g., events of tube disconnection and sleep apnea events) and has been successfully tested by means of experimental tests carried out with pulmonary ventilators typically used to support sick patients.

  20. Ventilation patterns of the songbird lung/air sac system during different behaviors.

    Science.gov (United States)

    Mackelprang, Rebecca; Goller, Franz

    2013-10-01

    Unidirectional, continuous airflow through the avian lung is achieved through an elaborate air sac system with a sequential, posterior to anterior ventilation pattern. This classical model was established through various approaches spanning passively ventilated systems to mass spectrometry analysis of tracer gas flow into various air sacs during spontaneous breathing in restrained ducks. Information on flow patterns in other bird taxa is missing, and these techniques do not permit direct tests of whether the basic flow pattern can change during different behaviors. Here we use thermistors implanted into various locations of the respiratory system to detect small pulses of tracer gas (helium) to reconstruct airflow patterns in quietly breathing and behaving (calling, wing flapping) songbirds (zebra finch and yellow-headed blackbird). The results illustrate that the basic pattern of airflow in these two species is largely consistent with the model. However, two notable differences emerged. First, some tracer gas arrived in the anterior set of air sacs during the inspiration during which it was inhaled, suggesting a more rapid throughput through the lung than previously assumed. Second, differences in ventilation between the two anterior air sacs emerged during calling and wing flapping, indicating that adjustments in the flow pattern occur during dynamic behaviors. It is unclear whether this modulation in ventilation pattern is passive or active. This technique for studying ventilation patterns during dynamic behaviors proves useful for establishing detailed timing of airflow and modulation of ventilation in the avian respiratory system.

  1. Alternatives generation and analysis for double-shell tank primary ventilation systems emissions control and monitoring

    Energy Technology Data Exchange (ETDEWEB)

    SEDERBURG, J.P.

    1999-09-30

    This AGA addresses the question: ''What equipment upgrades, operational changes, and/or other actions are required relative to the DST tanks farms' ventilation systems to support retrieval, staging (including feed sampling), and delivery of tank waste to the Phase I private contractor?'' Issues and options for the various components within the ventilation subsystem affect each other. Recommended design requirements are presented and the preferred alternatives are detailed.

  2. Some approaches to improve the ventilation system in underground potash mines

    OpenAIRE

    Bascompta Massanes, Marc

    2016-01-01

    Mine ventilation is a crucial factor for the sake of underground operations. Not only does it affect efficiency and effectiveness rates, but it also influence the health and safety of the employees. Despite it is a topic thoroughly analysed, every mine has its particularities and there is not much specific information concerning potash mines currently. This thesis investigates the main characteristics of the ventilation system in two potash mines, using a room and pillar method, with the i...

  3. Mobile zone, spray booth ventilation system. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1994-04-26

    This concept endeavors to reduce the volume of air (to be treated) from spray paint booths, thereby increasing efficiency and improving air pollution abatement (VOC emissions especially). Most of the ventilation air is recycled through the booth to maintain laminar flow; the machinery is located on the supply side of the booth rather than on the exhaust side. 60 to 95% reduction in spray booth exhaust rate should result. Although engineering and production prototypes have been made, demand is low.

  4. VENTILATION NEEDS DURING CONSTRUCTION

    Energy Technology Data Exchange (ETDEWEB)

    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.

  5. Dynamics of quasi-stable dissipative systems

    CERN Document Server

    Chueshov, Igor

    2015-01-01

    This book is  devoted to background material and recently developed mathematical methods in the study of infinite-dimensional dissipative systems. The theory of such systems is motivated by the long-term goal to establish rigorous mathematical models for turbulent and chaotic phenomena. The aim here is to offer general methods and abstract results pertaining to fundamental dynamical systems properties related to dissipative long-time behavior. The book systematically presents, develops and uses the quasi-stability method while substantially extending it by including for consideration new classes of models and PDE systems arising in Continuum Mechanics. The book can be used as a textbook in dissipative dynamics at the graduate level.   Igor Chueshov is a Professor of Mathematics at Karazin Kharkov National University in Kharkov, Ukraine.

  6. Economizer system cost effectiveness: Accounting for the influence of ventilation rate on sick leave

    Energy Technology Data Exchange (ETDEWEB)

    Fisk, William J.; Seppanen, Olli; Faulkner, David; Huang, Joe

    2003-06-01

    This study estimated the health, energy, and economic benefits of an economizer ventilation control system that increases outside air supply during mild weather to save energy. A model of the influence of ventilation rate on airborne transmission of respiratory illnesses was used to extend the limited data relating ventilation rate with illness and sick leave. An energy simulation model calculated ventilation rates and energy use versus time for an office building in Washington, DC with fixed minimum outdoor air supply rates, with and without an economizer. Sick leave rates were estimated with the disease transmission model. In the modeled 72-person office building, our analyses indicate that the economizer reduces energy costs by approximately $2000 and, in addition, reduces sick leave. The financial benefit of the decrease in sick leave is estimated to be between $6,000 and $16,000. This modelling suggests that economizers are much more cost effective than currently recognized.

  7. Assessment of Pollutant Spread from a Building Basement with three Ventilation Systems

    CERN Document Server

    Koffi, Juslin

    2010-01-01

    Ventilation aims at providing a sufficient air renewal for ensuring a good indoor air quality (IAQ), yet building energy policies are leading to adapting various ventilation strategies minimising energy losses through air renewal. A recent IAQ evaluation campaign in French dwellings shows important pollution of living spaces by VOCs such as formaldehyde, acetaldehyde or hexanal, particularly in buildings equipped with a garage. Besides, radon emission from soil is a subject of concern in many countries. Several studies are done to understand its release mode and deal with the spread of this carcinogen gas. This paper aims to experimentally assess a contaminant spread from a house basement using mechanical exhaust and balanced ventilation systems, and natural ventilation.

  8. Imaging of ventilation with dual-energy CT during breath hold after single vital-capacity inspiration of stable xenon.

    Science.gov (United States)

    Honda, Norinari; Osada, Hisato; Watanabe, Wataru; Nakayama, Mitsuo; Nishimura, Keiichiro; Krauss, Bernhard; Otani, Katharina

    2012-01-01

    To assess single-breath-hold technique for ventilation mapping by using dual-energy computed tomography (CT) in phantom experiments and volunteers. Institutional review board approved this study, and written informed consent was obtained from all volunteers. A rubber bag filled with a mixture of xenon (0%-35.4%) and oxygen was scanned with dual-source dual-energy CT (80 kV and 140 kV with tin [Sn] filter [Sn/140 kV] and 100 kV and Sn/140 kV). A cylinder containing six tubes of identical sizes with different apertures was ventilated once with a mixture of 35% xenon and 65% oxygen and was scanned in dual-energy mode (80 kV and Sn/140 kV). Xenon-enhanced images were derived by using three-material decomposition technique. Four volunteers were scanned twice in dual-energy mode (80 kV and Sn/140 kV) during breath hold after a single vital-capacity inspiration of air (nonenhanced) and of 35% xenon. Xenon-enhanced images were obtained by using two methods: three-material decomposition and subtraction of nonenhanced from xenon-enhanced images. Regression analysis with t and F tests was applied to the data of the rubber bag scans, with the significance level set at .05. Mean pixel values of gas in the bag were linearly related to xenon concentration for all x-ray tube voltages (r(2) = 1.00, P lungs of healthy volunteers, with higher pixel values in the trachea and lower pixel values in the bullae. Xenon-enhanced images calculated by using three-material decomposition had better image quality on visual comparison than those calculated by using subtraction. Xenon-enhanced dual-energy CT with the single-breath-hold technique could depict ventilation in phantoms and in four volunteers. © RSNA, 2011.

  9. Design Principles for Hybrid Ventilation

    DEFF Research Database (Denmark)

    Heiselberg, Per

    For many years mechanical and natural ventilation systems have developed separately. Naturally, the next step in this development is the development of ventilation concepts that utilize and combine the best features from each system to create a new type of ventilation system -Hybrid Ventilation. ....... The hybrid ventilation concepts, design challenges and - principles are discussed and illustrated by four building examples....

  10. Application of enriched stable isotopes as tracers in biological systems

    DEFF Research Database (Denmark)

    Stürup, Stefan; Hansen, Helle Rüsz; Gammelgaard, Bente

    2008-01-01

    The application of enriched stable isotopes of minerals and trace elements as tracers in biological systems is a rapidly growing research field that benefits from the many new developments in inorganic mass spectrometric instrumentation, primarily within inductively coupled plasma mass spectrometry......, and the development of new methodologies coupled with more advanced compartmental and mathematical models for the distribution of elements in living organisms has enabled a broader use of enriched stable isotope experiments in the biological sciences. This review discusses the current and future uses of enriched...... stable isotope experiments in biological systems....

  11. Dynamic Characteristics of Mechanical Ventilation System of Double Lungs with Bi-Level Positive Airway Pressure Model

    Directory of Open Access Journals (Sweden)

    Dongkai Shen

    2016-01-01

    Full Text Available In recent studies on the dynamic characteristics of ventilation system, it was considered that human had only one lung, and the coupling effect of double lungs on the air flow can not be illustrated, which has been in regard to be vital to life support of patients. In this article, to illustrate coupling effect of double lungs on flow dynamics of mechanical ventilation system, a mathematical model of a mechanical ventilation system, which consists of double lungs and a bi-level positive airway pressure (BIPAP controlled ventilator, was proposed. To verify the mathematical model, a prototype of BIPAP system with a double-lung simulators and a BIPAP ventilator was set up for experimental study. Lastly, the study on the influences of key parameters of BIPAP system on dynamic characteristics was carried out. The study can be referred to in the development of research on BIPAP ventilation treatment and real respiratory diagnostics.

  12. Faster reduction in hyperinflation and improvement in lung ventilation inhomogeneity promoted by aclidinium compared to glycopyrronium in severe stable COPD patients. A randomized crossover study.

    Science.gov (United States)

    Santus, Pierachille; Radovanovic, Dejan; Di Marco, Fabiano; Raccanelli, Rita; Valenti, Vincenzo; Centanni, Stefano

    2015-12-01

    Standard spyrometric assessment in chronic obstructive pulmonary disease (COPD) only evaluates bronchial obstruction. However, airflow limitation and hyperinflation are the main pathophysiological factors responsible for dyspnoea and reduced exercise tolerance in patients with COPD. This study evaluated the effects of aclidinium bromide 400 μg and glycopyrronium bromide 50 μg on these parameters. Patients with stable severe/very severe COPD were randomized in this double-blind, double-dummy, crossover, Phase IV study. Patients received single doses of each drug on separate days. Primary endpoints were changes in residual volume (RV) and intra-thoracic gas volume (ITGV), assessed by full-body plethysmography. Other endpoints included changes variations in lung ventilation inhomogeneity (Phase III slope of single-breath nitrogen washout test, SBN2), dyspnoea visual analogue scale, and pulmonary specific total airway resistances. Assessments were performed at baseline and 5, 15, 30, 60, and 180 min post-administration. Thirty-seven patients were randomized (31 male; mean age 71 years). Aclidinium and glycopyrronium significantly improved ITGV versus baseline at all-time points (p ventilation inhomogeneity versus baseline at all-time points; no significant changes were observed for glycopyrronium. For the first time two long-acting muscarinic antagonists have been compared in acute conditions with body plethysmography and SBN2 test. We demonstrated that both aclidinium and glycopyrronium significantly reduce hyperinflation and dyspnoea in severe and very severe COPD patients. Aclidinium however promoted a faster reduction in RV and was the only able to reduce lung ventilation inhomogeneity. Trial Registration numbers available on Clinicaltrials.gov: NCT02181023. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Combining a building simulation with energy systems analysis to assess the benefits of natural ventilation

    DEFF Research Database (Denmark)

    Oropeza-Perez, Ivan; Østergaard, Poul Alberg; Remmen, Arne

    2013-01-01

    a thermal air flow simulation program - Into the energy systems analysis model. Descriptions of the energy systems in two geographical locations, i.e. Mexico and Denmark, are set up as inputs. Then, the assessment is done by calculating the energy impacts as well as environmental benefits in the energy......This article shows the combination of a thermal air flow simulation program with an energy systems analysis model in order to assess the use of natural ventilation as a method for saving energy within residential buildings in large-scale scenarios. The aim is to show the benefits for utilizing...... natural airflow instead of active systems such as mechanical ventilation or air-conditioning in buildings where the indoor temperature is over the upper limit of the comfort range. The combination is done by introducing the energy saving output - calculated with a model of natural ventilation using...

  14. Ventilator graphics.

    Science.gov (United States)

    Prabhakaran, Priya; Sasser, William C; Kalra, Yuvrai; Rutledge, Chrystal; Tofil, Nancy M

    2016-12-01

    Providing optimal mechanical ventilation to critically-ill children remains a challenge. Patient-ventilator dyssynchrony results frequently with numerous deleterious consequences on patient outcome including increased requirement for sedation, prolonged duration of ventilation, and greater imposed work of breathing. Most currently used ventilators have real-time, continuously-displayed graphics of pressure, volume, and flow versus time (scalars) as well as pressure, and flow versus volume (loops). A clear understanding of these graphics provides a lot of information about the mechanics of the respiratory system and the patient ventilator interaction in a dynamic fashion. Using this information will facilitate tailoring the support provided and the manner in which it is provided to best suit the dynamic needs of the patient. This paper starts with a description of the scalars and loops followed by a discussion of the information that can be obtained from each of these graphics. A review will follow, on the common types of dyssynchronous interactions and how each of these can be detected on the ventilator graphics. The final section discusses how graphics can be used to optimize the ventilator support provided to patients.

  15. Procedures and Standards for Residential Ventilation System Commissioning: An Annotated Bibliography

    Energy Technology Data Exchange (ETDEWEB)

    Stratton, J. Chris [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Wray, Craig P. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2013-04-01

    Beginning with the 2008 version of Title 24, new homes in California must comply with ANSI/ASHRAE Standard 62.2-2007 requirements for residential ventilation. Where installed, the limited data available indicate that mechanical ventilation systems do not always perform optimally or even as many codes and forecasts predict. Commissioning such systems when they are installed or during subsequent building retrofits is a step towards eliminating deficiencies and optimizing the tradeoff between energy use and acceptable IAQ. Work funded by the California Energy Commission about a decade ago at Berkeley Lab documented procedures for residential commissioning, but did not focus on ventilation systems. Since then, standards and approaches for commissioning ventilation systems have been an active area of work in Europe. This report describes our efforts to collect new literature on commissioning procedures and to identify information that can be used to support the future development of residential-ventilation-specific procedures and standards. We recommend that a standardized commissioning process and a commissioning guide for practitioners be developed, along with a combined energy and IAQ benefit assessment standard and tool, and a diagnostic guide for estimating continuous pollutant emission rates of concern in residences (including a database that lists emission test data for commercially-available labeled products).

  16. The influence of an estimated energy saving due to natural ventilation on the Mexican energy system

    DEFF Research Database (Denmark)

    Oropeza-Perez, Ivan; Østergaard, Poul Alberg

    2014-01-01

    This article shows the impacts of the extensive use of NV (natural ventilation) in the Mexican residential sector on the Mexican energy system. By integrating a thermal-airflow simulation programme with an energy systems analysis model, the impact on the Mexican energy system of replacing air...... conditioning, in particular, with natural ventilation to cool residential buildings is determined. It is shown that when, as in Mexico, there is a relatively simple connection between supply and electricity demand, NV creates savings which could be used to reduce either the fossil-fuel-based generation...

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

    Science.gov (United States)

    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.

  18. Assessment of Natural Ventilation System for a Typical Residential House in Poland

    Science.gov (United States)

    Antczak-Jarząbska, Romana; Krzaczek, Marek

    2016-09-01

    The paper presents the research results of field measurements campaign of natural ventilation performance and effectiveness in a residential building. The building is located in the microclimate whose parameters differ significantly in relation to a representative weather station. The measurement system recorded climate parameters and the physical variables characterizing the air flow in the rooms within 14 days of the winter season. The measurement results showed that in spite of proper design and construction of the ventilation system, unfavorable microclimatic conditions that differed from the predicted ones caused significant reduction in the efficiency of the ventilation system. Also, during some time periods, external climate conditions caused an opposite air flow direction in the vent inlets and outlets, leading to a significant deterioration of air quality and thermal comfort measured by CO2 concentration and PMV index in a residential area.

  19. Parameter estimation of an artificial respiratory system under mechanical ventilation following a noisy regime

    Directory of Open Access Journals (Sweden)

    Marcus Henrique Victor Júnior

    Full Text Available Abstract Introduction: This work concerns the assessment of a novel system for mechanical ventilation and a parameter estimation method in a bench test. The tested system was based on a commercial mechanical ventilator and a personal computer. A computational routine was developed do drive the mechanical ventilator and a parameter estimation method was utilized to estimate positive end-expiratory pressure, resistance and compliance of the artificial respiratory system. Methods The computational routine was responsible for establishing connections between devices and controlling them. Parameters such as tidal volume, respiratory rate and others can be set for standard and noisy ventilation regimes. Ventilation tests were performed directly varying parameters in the system. Readings from a calibrated measuring device were the basis for analysis. Adopting a first-order linear model, the parameters could be estimated and the outcomes statistically analysed. Results Data acquisition was effective in terms of sample frequency and low noise content. After filtering, cycle detection and estimation took place. Statistics of median, mean and standard deviation were calculated, showing consistent matching with adjusted values. Changes in positive end-expiratory pressure statistically imply changes in compliance, but not the opposite. Conclusion The developed system was satisfactory in terms of clinical parameters. Statistics exhibited consistent relations between adjusted and estimated values, besides precision of the measurements. The system is expected to be used in animals, with a view to better understand the benefits of noisy ventilation, by evaluating the estimated parameters and performing cross relations among blood gas, ultrasonography and electrical impedance tomography.

  20. High-intensity versus low-intensity non-invasive ventilation in patients with stable hypercapnic COPD: a randomised crossover trial.

    Science.gov (United States)

    Dreher, Michael; Storre, Jan H; Schmoor, Claudia; Windisch, Wolfram

    2010-04-01

    The conventional approach of low-intensity non-invasive positive pressure ventilation (NPPV) produces only minimal physiological and clinical benefits in patients with stable hypercapnic chronic obstructive pulmonary disease (COPD). To determine whether the novel approach of high-intensity NPPV is superior to low-intensity NPPV in controlling nocturnal hypoventilation. A randomised controlled crossover trial comparing 6 weeks of high-intensity NPPV (using controlled ventilation with mean inspiratory pressures of 28.6+/-1.9 mbar) with low-intensity NPPV (using assisted ventilation with mean inspiratory pressures of 14.6+/-0.8 mbar) was performed in 17 patients with severe stable hypercapnic COPD. Two patients refused low-intensity NPPV and two patients dropped out while on low-intensity NPPV. Thirteen patients (mean forced expiratory volume in 1 s (FEV(1)) 0.76+/-0.29 l) completed the trial. High-intensity NPPV produced higher pneumotachographically-measured expiratory volumes, with a mean treatment effect of 96 ml (95% CI 23 to 169) (p=0.015). This resulted in a mean treatment effect on nocturnal arterial carbon dioxide tension (Paco(2)) of -9.2 mm Hg (95% CI -13.7 to -4.6) (p=0.001) in favour of high-intensity NPPV. Daily use of NPPV was increased in high-intensity NPPV compared with low-intensity NPPV, with a mean difference of 3.6 h/day (95% CI 0.6 to 6.7) (p=0.024). In addition, compared with baseline, only high-intensity NPPV resulted in significant improvements in exercise-related dyspnoea, daytime Paco(2), FEV(1), vital capacity and the Severe Respiratory Insufficiency Questionnaire Summary Score. High-intensity NPPV is better tolerated by patients with severe chronic hypercapnic COPD and has been shown to be superior to the conventional and widely-used form of low-intensity NPPV in controlling nocturnal hypoventilation. High-intensity NPPV therefore offers a new promising therapeutic option for these patients.

  1. Microprocessor-controlled ventilation system in the House of German-Soviet Friendship in Dresden

    Energy Technology Data Exchange (ETDEWEB)

    Naumann, B.

    1983-01-01

    A description is given of the use of a universal programmable PS 2000 control system and peripherals in a prototype project to control ventilation systems. Reference is made to the partial operations, of control and monitoring of the fan and pump drives, multi-channel governors, actuator control and automatic timing. New problems occurring in preparation and implementation are outlined.

  2. Best clinical practices for the sleep center adjustment of noninvasive positive pressure ventilation (NPPV) in stable chronic alveolar hypoventilation syndromes.

    Science.gov (United States)

    Berry, Richard B; Chediak, Alejandro; Brown, Lee K; Finder, Jonathan; Gozal, David; Iber, Conrad; Kushida, Clete A; Morgenthaler, Timothy; Rowley, James A; Davidson-Ward, Sally L

    2010-10-15

    Noninvasive positive pressure ventilation (NPPV) devices are used during sleep to treat patients with diurnal chronic alveolar hypoventilation (CAH). Bilevel positive airway pressure (BPAP) using a mask interface is the most commonly used method to provide ventilatory support in these patients. BPAP devices deliver separately adjustable inspiratory positive airway pressure (IPAP) and expiratory positive airway pressure (EPAP). The IPAP and EPAP levels are adjusted to maintain upper airway patency, and the pressure support (PS = IPAP-EPAP) augments ventilation. NPPV devices can be used in the spontaneous mode (the patient cycles the device from EPAP to IPAP), the spontaneous timed (ST) mode (a backup rate is available to deliver IPAP for the set inspiratory time if the patient does not trigger an IPAP/EPAP cycle within a set time window), and the timed (T) mode (inspiratory time and respiratory rate are fxed). During NPPV titration with polysomnography (PSG), the pressure settings, backup rate, and inspiratory time (if applicable) are adjusted to maintain upper airway patency and support ventilation. However, there are no widely available guidelines for the titration of NPPV in the sleep center. A NPPV Titration Task Force of the American Academy of Sleep Medicine reviewed the available literature and developed recommendations based on consensus and published evidence when available. The major recommendations derived by this consensus process are as follows: General Recommendations: 1. The indications, goals of treatment, and side effects of NPPV treatment should be discussed in detail with the patient prior to the NPPV titration study. 2. Careful mask fitting and a period of acclimatization to low pressure prior to the titration should be included as part of the NPPV protocol. 3. NPPV titration with PSG is the recommended method to determine an effective level of nocturnal ventilatory support in patients with CAH. In circumstances in which NPPV treatment is

  3. The Design and Simulation of Natural Personalised Ventilation (NPV System for Multi-Bed Hospital Wards

    Directory of Open Access Journals (Sweden)

    Zulfikar A. Adamu

    2015-05-01

    Full Text Available Adequate ventilation is necessary for thermal comfort and reducing risks from infectious bio-aerosols in hospital wards, but achieving this with mechanical ventilation has carbon and energy implications. Natural ventilation is often limited to window-based designs whose dilution/mixing effectiveness are subject to constraints of wind speed, cross ventilation, and in the case of hospital wards, proximity of patients to external walls. A buoyancy-driven natural ventilation system capable of achieving dilution/mixing was shown to be feasible in a preceding study of novel system called natural personalised ventilation (NPV. This system combined both architecture and airflow engineering principles of space design and buoyancy and was tested and validated (salt-bath experiment for a single bed ward. This research extends the previous work and is proof-of-concept on the feasibility of NPV system for multi-bed wards. Two different four-bed ward types were investigated of using computational fluid dynamics (CFD simulations under wind-neutral conditions. Results predict that NPV system could deliver fresh air to multiple patients, including those located 10 m away from external wall, with absolute flow rates of between 32 L·s−1 and 54 L·s−1 for each patient/bed. Compared to same wards simulated using window design, ingress of airborne contaminants into patients’ breathing zone and summer overheating potential were minimised, while overall ward dilution was maximised. Findings suggest the NPV has potentials for enabling architects and building service engineers to decouple airflow delivery from the visualisation and illumination responsibilities placed upon windows.

  4. ADMINISTRATIVE AND ENGINEERING CONTROLS FOR THE OPERATION OF VENTILATION SYSTEMS FOR UNDERGROUND RADIOACTIVE WASTE STORAGE TANKS

    Energy Technology Data Exchange (ETDEWEB)

    Wiersma, B.; Hansen, A.

    2013-11-13

    Liquid radioactive wastes from the Savannah River Site are stored in large underground carbon steel tanks. The majority of the waste is confined in double shell tanks, which have a primary shell, where the waste is stored, and a secondary shell, which creates an annular region between the two shells, that provides secondary containment and leak detection capabilities should leakage from the primary shell occur. Each of the DST is equipped with a purge ventilation system for the interior of the primary shell and annulus ventilation system for the secondary containment. Administrative flammability controls require continuous ventilation to remove hydrogen gas and other vapors from the waste tanks while preventing the release of radionuclides to the atmosphere. Should a leak from the primary to the annulus occur, the annulus ventilation would also serve this purpose. The functionality of the annulus ventilation is necessary to preserve the structural integrity of the primary shell and the secondary. An administrative corrosion control program is in place to ensure integrity of the tank. Given the critical functions of the purge and annulus ventilation systems, engineering controls are also necessary to ensure that the systems remain robust. The system consists of components that are constructed of metal (e.g., steel, stainless steel, aluminum, copper, etc.) and/or polymeric (polypropylene, polyethylene, silicone, polyurethane, etc.) materials. The performance of these materials in anticipated service environments (e.g., normal waste storage, waste removal, etc.) was evaluated. The most aggressive vapor space environment occurs during chemical cleaning of the residual heels by utilizing oxalic acid. The presence of NO{sub x} and mercury in the vapors generated from the process could potentially accelerate the degradation of aluminum, carbon steel, and copper. Once identified, the most susceptible materials were either replaced and/or plans for discontinuing operations

  5. Cleanup and Dismantling of Highly Contaminated Ventilation Systems Using Robotic Tools - 13162

    Energy Technology Data Exchange (ETDEWEB)

    Chambon, Frederic [AREVA FEDERAL SERVICES, Columbia MD (United States); CIZEL, Jean-Pierre [AREVA BE/NV, Marcoule (France); Blanchard, Samuel [CEA DEN/DPAD, Marcoule (France)

    2013-07-01

    The UP1 plant reprocessed nearly 20,000 tons of used natural uranium gas cooled reactor fuel coming from the first generation of civil nuclear reactors in France. Following operating incidents in the eighties, the ventilation system of the continuous dissolution line facility was shut down and replaced. Two types of remote controlled tool carriers were developed to perform the decontamination and dismantling operations of the highly contaminated ventilation duct network. The first one, a dedicated small robot, was designed from scratch to retrieve a thick powder deposit within a duct. The robot, managed and confined by two dedicated glove boxes, was equipped for intervention inside the ventilation duct and used for carrying various cleanup and inspection tools. The second type, consisting of robotic tools developed on the base of an industrial platform, was used for the clean-up and dismantling of the ventilation duct system. Depending on the type of work to be performed, on the shape constraints of the rooms and any equipment to be dismantled, different kinds of robotic tools were developed and installed on a Brokk 40 carrier. After more than ten years of ventilation duct D and D operations at the UP1 plant, a lot of experience was acquired about remote operations. The three main important lessons learned in terms of remote controlled operation are: characterizing the initial conditions as much as reasonably possible, performing non-radioactive full scale testing and making it as simple and modular as possible. (authors)

  6. CFD-based design of the ventilation system for the PHENIX detector

    Energy Technology Data Exchange (ETDEWEB)

    Parietti, L.; Martin, R.A.; Gregory, W.S.

    1996-10-01

    The three-dimensional flow and thermal fields surrounding the large PHENIX sub-atomic particle detector enclosed in the Major Facility Hall are simulated numerically in this study using the CFX finite volume, commercial, computer code. The predicted fields result from the interaction of an imposed downward ventilation system cooling flow and a buoyancy-driven thermal plume rising from the warm detector. An understanding of the thermal irregularities on the surface of the detector and in the flow surrounding is needed to assess the potential for adverse thermal expansion effects in detector subsystems, and to prevent ingestion of electronics cooling air from hot spots. With a computational model of the thermal fields on and surrounding the detector, HVAC engineers can evaluate and improve the ventilation system design prior to the start of construction. This paper summarizes modeling and results obtained for a conceptual MFH ventilation scheme.

  7. Experimental Evaluation of Ventilation Systems in a Single-Family Dwelling

    CERN Document Server

    Koffi, Juslin; Akoua, Jean-Jacques

    2010-01-01

    The French regulation on residential building ventilation relies on an overall and continuous air renewal. The fresh air should enter the building through the "habitable rooms" while the polluted air is extracted in the service rooms. In this way, internal air is drained from the lowest polluted rooms to the highest polluted ones. However, internal pressure equilibrium and air movements in buildings result from the combined effects ventilation system and parameters such as wind, temperature difference or doors opening. This paper aims to analyse the influence of these parameters on pollutant transfer within buildings. In so doing, experiments are carried out using tracer gas release for representing pollution sources in an experimental house. Mechanical exhaust, balanced and natural ventilation systems are thus tested. Results show the followings: - For all cases, internal doors' opening causes the most important pollutant spread. - When doors are closed, the best performances are obtained with balanced venti...

  8. Efficacy of long-term noninvasive positive pressure ventilation in stable hypercapnic COPD patients with respiratory failure: a meta-analysis of randomized controlled trials

    Directory of Open Access Journals (Sweden)

    Liao H

    2017-10-01

    Full Text Available Hao Liao,* Wendi Pei,* Hongfu Li,* Yuwen Luo, Kai Wang, Rui Li, Limei Xu, Xin Chen Department of Respiratory Medicine, Zhujiang Hospital, Southern Medical University, Guangzhou, People’s Republic of China *These authors contributed equally to this work Introduction: The efficacy of long-term noninvasive positive pressure ventilation (NPPV in stable hypercapnic COPD patients with respiratory failure remains unclear. The aim of this meta-analysis was to critically assess the efficacy of long-term NPPV on mortality, acute exacerbation, exercise capacity, symptoms and significant physiological parameters (lung function, respiratory muscle function and gas exchange.Patients and methods: We performed an electronic literature search using the PubMed, Cochrane Library, Embase, OVID and Chinese Biomedical Literature Database in May 2017. Studies comparing treatment effects of NPPV with oxygen therapy in stable hypercapnic COPD patients with respiratory failure were conducted, and at least one of the following parameters were reviewed: frequency of acute exacerbation, mortality, lung function, respiratory muscle function, gas exchange, exercise capacity.Results: Seven studies with 810 subjects were identified. The partial pressure of arterial carbon dioxide (PaCO2 significantly decreased in patients who received long-term NPPV (weighted mean difference [WMD] −3.73, 95% CI: −5.83 to −1.64, P=0.0005. No significant difference was found in mortality, partial pressure of arterial oxygen (PaO2, frequency of acute exacerbation, lung function, respiratory muscle function and exercise capacity. The subgroup analysis showed that NPPV significantly improved the survival of patients when it was targeted at greatly reducing hypercapnia (WMD 0.35, 95% CI: 0.19 to 0.64, P=0.0006.Conclusion: The results indicate that long-term NPPV decreases the PaCO2 of stable hypercapnic COPD patients with respiratory failure and improves mortality with the aim of reducing Pa

  9. AUTOPILOT-BT: a system for knowledge and model based mechanical ventilation.

    Science.gov (United States)

    Lozano, S; Möller, K; Brendle, A; Gottlieb, D; Schumann, S; Stahl, C A; Guttmann, J

    2008-01-01

    A closed-loop system (AUTOPILOT-BT) for the control of mechanical ventilation was designed to: 1) autonomously achieve goals specified by the clinician, 2) optimize the ventilator settings with respect to the underlying disease and 3) automatically adapt to the individual properties and specific disease status of the patient. The current realization focuses on arterial oxygen saturation (SpO(2)), end-tidal CO(2) pressure (P(et)CO(2)), and positive end-expiratory pressure (PEEP) maximizing respiratory system compliance (C(rs)). The "AUTOPILOT-BT" incorporates two different knowledge sources: a fuzzy logic control reflecting expert knowledge and a mathematical model based system that provides individualized patient specific information. A first evaluation test with respect to desired end-tidal-CO(2)-level was accomplished using an experimental setup to simulate three different metabolic CO(2) production rates by means of a physical lung simulator. The outcome of ventilator settings made by the "AUTOPILOT-BT" system was compared to those produced by clinicians. The model based control system proved to be superior to the clinicians as well as to a pure fuzzy logic based control with respect to precision and required settling time into the optimal ventilation state.

  10. The effect of a personalized ventilation system on perceived air quality and SBS symptoms

    DEFF Research Database (Denmark)

    Kaczmarczyk, Jan; Zeng, Q.; Melikov, Arsen Krikor

    2002-01-01

    Perceived air quality, SBS symptoms and performance were studied with 30 human subjects. Experiments were performed in an office set-up with six workplaces, each equipped with a Personalized Ventilation System (PVS). Each PVS allowed the amount of supply air and its direction to be controlled....... Subjects participated in four experiments: (1) PVS supplying outdoor air at 20 deg.C; (2) PVS supplying outdoor air at 23 deg.C; (3) PVS supplying recirculated room air; and (4) mixing ventilation. Room temperature was kept constant at 23 deg.C and relative humidity at 30%. Results showed that the best...

  11. Development of mechanical ventilation system with low energy consumption for renovation of buildings

    DEFF Research Database (Denmark)

    Terkildsen, Søren

    in reducing CO2-emmissions. Over the last decade, initiatives have been taken to reduce its energy consumption e.g. by the European Union, national governments or NGOs. The initiatives have mostly focused on improving the thermal properties of the building envelope to reduce heat losses. Building services......A general reduction in total energy consumption is needed, due to the increasing concerns about climate change caused by CO2-emmissions from fossil fuels. In 2004, the building sector accounted for 40% of the total energy consumption in the EU and the US and therefore must play a crucial role......, including ventilation, therefore now represent a larger part of the total energy consumption. Mechanical ventilation has been the most widely used principle of ventilation over the last 50 years, but the conventional system design needs revising to meet future energy requirements. The increase in the use...

  12. Automated Control of Shipboard Ventilation Systems: Phase 2 Part B Test Results (CD-ROM)

    Science.gov (United States)

    Smoke Control Dampers and fourteen Smoke Purge Dampers. Most of the ventilation terminals serve the Main and 2nd Decks, and to a lesser extent, the 01 Level and 03 Decks. Under the existing control system, the SES system is capable of two modes of operation, Collective Protection System (CPS) and SES. These two modes were replaced by a single automated mode, AUTO mode. This system takes its cues from sensors and automatically goes to smoke ejection under fire and smoke

  13. Design, Implementation & Assessment of Local Exhaust Ventilation System and dust collectors for crushing unit

    Directory of Open Access Journals (Sweden)

    Farshid Ghorbani shahna

    2015-09-01

    Full Text Available Background & objective: Industrial ventilation systems and dust collectors are effective solutions to reduce particulate emissions in the workplace and environmental in mineral processes. In this study, Local Exhaust Ventilation System and dust collectors for control of emitted silica, coke, silicon carbide dusts from crushing unit was designed and evaluated. Methods: : Local Exhaust ventilation system based on standards and guides was designed and implemented after field study of the processes and sources of air pollutants. A set comprised of the four parallel cyclones (Stairmand model and a new design of the scrubber had been used for dust control. After set-up of systems, its effectiveness in reducing the exposure of workers in the workshops and dust collecting were assessed. Results: Test results were significant differences between the concentration of particles in both on and off the ventilation system revealed (P <0.05. The system has been implemented as means of personal exposure to pollutants and environmental emissions were reduced 93.01% and 64.64%, respectively. Also, alone and integrated collection efficiency of cyclone and scrubber, were 94.2%, 59.05% and 97.4%, respectively. The results show good agreement with the values of the parameters ventilation system was designed. Conclusion: Implementation of integrated dust collectors is a good option in industries that have the financial and technical constraints to improve change processes and devices. This method with attainment to health and environmental standards not only can be resolve of the pollution problems, but also will be economically justified of such projects with reduction of depreciation expense and dust recycling.

  14. Experimental study of a semi-passive ventilation grille with a feedback control system

    Science.gov (United States)

    D'Orazio, A.; Fontana, L.; Salata, F.

    2011-08-01

    The diffusion of window frames with low air permeability, due to the energy saving regulations, has implied in several cases the worsening of the indoor microclimate and air quality. On the other hand, air-tight window frames imply uncontrolled and too high air change rates. The mechanical ventilation not always is a practicable solution because of economic reasons and because it implies energy waste. Various Italian and European environmental and energetic laws take into consideration and promote the use of controlled natural ventilation, though this definition is not associated to well defined and tested technical solutions. An adequate solution can be achieved by using semi-passive self adjustable ventilation devices, able to ensure controlled changes of indoor air. In this paper, a semi-passive damper with a feedback control system is proposed and its behavior is investigated by means of experimental study. The presented semi-passive grille allows to control the air flow rate, injected into the room by natural or artificial pressure gradient, more effectively than the usual passive ventilation grilles made available by the present industrial production. However, since the semi-passive grille has a one-way flow, in the natural ventilation of a flat the proper functioning of the system could be ensured with a more complex configuration, with respect to the passive self-regulating grilles, able to limit the flow of fresh air in the presence of high levels of Δp; conversely, it could have widespread use in applications requiring a more accurate control of airflow in case of mechanical ventilation plants.

  15. Diffuse ceiling ventilation

    DEFF Research Database (Denmark)

    Zhang, Chen

    Diffuse ceiling ventilation is an innovative ventilation concept where the suspended ceiling serves as air diffuser to supply fresh air into the room. Compared with conventional ventilation systems, diffuse ceiling ventilation can significantly reduce or even eliminate draught risk due to the low...... momentum supply. In addition, this ventilation system uses a ceiling plenum to deliver air and requires less energy consumption for air transport than full-ducted systems. There is a growing interest in applying diffuse ceiling ventilation in offices and other commercial buildings due to the benefits from...... both thermal comfort and energy efficient aspects. The present study aims to characterize the air distribution and thermal comfort in the rooms with diffuse ceiling ventilation. Both the stand-alone ventilation system and its integration with a radiant ceiling system are investigated. This study also...

  16. Stable habitable zones of single Jovian planet systems

    Science.gov (United States)

    Agnew, Matthew T.; Maddison, Sarah T.; Thilliez, Elodie; Horner, Jonathan

    2017-11-01

    With continued improvement in telescope sensitivity and observational techniques, the search for rocky planets in stellar habitable zones is entering an exciting era. With so many exoplanetary systems available for follow-up observations to find potentially habitable planets, one needs to prioritize the ever-growing list of candidates. We aim to determine which of the known planetary systems are dynamically capable of hosting rocky planets in their habitable zones, with the goal of helping to focus future planet search programmes. We perform an extensive suite of numerical simulations to identify regions in the habitable zones of single Jovian planet systems where Earth-mass planets could maintain stable orbits, specifically focusing on the systems in the Catalog of Earth-like Exoplanet Survey Targets (CELESTA). We find that small, Earth-mass planets can maintain stable orbits in cases where the habitable zone is largely, or partially, unperturbed by a nearby Jovian, and that mutual gravitational interactions and resonant mechanisms are capable of producing stable orbits even in habitable zones that are significantly or completely disrupted by a Jovian. Our results yield a list of 13 single Jovian planet systems in CELESTA that are not only capable of supporting an Earth-mass planet on stable orbits in their habitable zone, but for which we are also able to constrain the orbits of the Earth-mass planet such that the induced radial velocity signals would be detectable with next generation instruments.

  17. Experimental Study of an Integrated System with Diffuse Ceiling Ventilation and Thermally Activated Building Constructions

    DEFF Research Database (Denmark)

    Zhang, Chen; Yu, Tao; Heiselberg, Per

    The experiments are carried out in a climate chamber located at the Department of Civil Engineering Aalborg University. The objective of the experiments is to evaluate the performance of the system combining diffuse ceiling ventilation and thermally activated building construction (TABS) in terms...

  18. A method for evaluating the problem complex of choosing the ventilation system for a new building

    DEFF Research Database (Denmark)

    Hviid, Christian Anker; Svendsen, Svend

    2007-01-01

    The application of a ventilation system in a new building is a multidimensional complex problem that involves quantifiable and non-quantifiable data like energy consump¬tion, indoor environment, building integration and architectural expression. This paper presents a structured method for evaluat...

  19. Calculation notes in support of ammonia releases from waste tank ventilation systems

    Energy Technology Data Exchange (ETDEWEB)

    Wojdac, L.F.

    1996-09-05

    Ammonia is generated in waste tanks via the degradation of nitrogen compounds. The ammonia is released from the liquids by a mechanism which is dependent on temperature, pH, ionic strength and ammonia concentration. The release of ammonia to the environment occurs via diffusion of ammonia through a stagnant air mass and into the ventilation system.

  20. The respiratory system during resuscitation: a review of the history, risk of infection during assisted ventilation, respiratory mechanics, and ventilation strategies for patients with an unprotected airway.

    Science.gov (United States)

    Wenzel, V; Idris, A H; Dörges, V; Nolan, J P; Parr, M J; Gabrielli, A; Stallinger, A; Lindner, K H; Baskett, P J

    2001-05-01

    The fear of acquiring infectious diseases has resulted in reluctance among healthcare professionals and the lay public to perform mouth-to-mouth ventilation. However, the benefit of basic life support for a patient in cardiopulmonary or respiratory arrest greatly outweighs the risk for secondary infection in the rescuer or the patient. The distribution of ventilation volume between lungs and stomach in the unprotected airway depends on patient variables such as lower oesophageal sphincter pressure, airway resistance and respiratory system compliance, and the technique applied while performing basic or advanced airway support, such as head position, inflation flow rate and time, which determine upper airway pressure. The combination of these variables determines gas distribution between the lungs and the oesophagus and subsequently, the stomach. During bag-valve-mask ventilation of patients in respiratory or cardiac arrest with oxygen supplementation (> or = 40% oxygen), a tidal volume of 6-7 ml kg(-1) ( approximately 500 ml) given over 1-2 s until the chest rises is recommended. For bag-valve-mask ventilation with room-air, a tidal volume of 10 ml kg(-1) (700-1000 ml) in an adult given over 2 s until the chest rises clearly is recommended. During mouth-to-mouth ventilation, a breath over 2 s sufficient to make the chest rise clearly (a tidal volume of approximately 10 ml kg(-1) approximately 700-1000 ml in an adult) is recommended.

  1. Positioning of sensors for control of ventilation systems in broiler houses: a case study

    Directory of Open Access Journals (Sweden)

    Thayla Morandi Ridolfi de Carvalho Curi

    Full Text Available ABSTRACT Ventilation systems are incorporated at intensive poultry farms to control environment conditions and thermal comfort of broilers. The ventilation system operates based on environmental data, particularly measured by sensors of temperature and relative humidity. Sensors are placed at different positions of the facility. Quality, number and positioning of the sensors are critical factors to achieve an efficient performance of the system. For this reason, a strategic positioning of the sensors associated to controllers could support the maintenance and management of the microclimate inside the facility. This research aims to identify the three most representative points for the positioning of sensors in order to support the ventilation system during the critical period from 12h00 to 15h00 on summer days. Temperature, relative humidity and wind speed were measured in four different tunnel ventilated barns at the final stage of the production cycle. The descriptive analysis was performed on these data. The Temperature and Humidity Index (THI was also calculated. Then, the geostatistical analysis of THI was performed by GS+ and the position of sensors was determined by ordinary kriging. The methodology was able to detect the most representative points for the positioning of sensors in a case study (southeastern Brazil. The results suggested that this strategic positioning would help controllers to obtain a better inference of the microclimate during the studied period (the hottest microclimate, considered critical in Brazil. In addition, these results allow developing a future road map for a decision support system based on 24 h monitoring of the ventilation systems in broiler houses.

  2. A novel fiber-optic measurement system for the evaluation of performances of neonatal pulmonary ventilators

    Science.gov (United States)

    Battista, L.; Scorza, A.; Botta, F.; Sciuto, S. A.

    2016-02-01

    Published standards for the performance evaluation of pulmonary ventilators are mainly directed to manufacturers rather than to end-users and often considered inadequate or not comprehensive. In order to contribute to overcome the problems above, a novel measurement system was proposed and tested with waveforms of mechanical ventilation by means of experimental trials carried out with infant ventilators typically used in neonatal intensive care units: the main quantities of mechanical ventilation in newborns are monitored, i.e. air flow rate, differential pressure and volume from infant ventilator are measured by means of two novel fiber-optic sensors (OFSs) developed and characterized by the authors, while temperature and relative humidity of air mass are obtained by two commercial transducers. The proposed fiber-optic sensors (flow sensor Q-OFS, pressure sensor P-OFS) showed measurement ranges of air flow and pressure typically encountered in neonatal mechanical ventilation, i.e. the air flow rate Q ranged from 3 l min-1 to 18 l min-1 (inspiratory) and from  -3 l min-1 to  -18 l min-1 (expiratory), the differential pressure ΔP ranged from  -15 cmH2O to 15 cmH2O. In each experimental trial carried out with different settings of the ventilator, outputs of the OFSs are compared with data from two reference sensors (reference flow sensor RF, reference pressure sensor RP) and results are found consistent: flow rate Q showed a maximum error between Q-OFS and RF up to 13 percent, with an output ratio Q RF/Q OFS of not more than 1.06  ±  0.09 (least square estimation, 95 percent confidence level, R 2 between 0.9822 and 0.9931). On the other hand the maximum error between P-OFS and RP on differential pressure ΔP was lower than 10 percent, with an output ratio ΔP RP/ΔP OFS between 0.977  ±  0.022 and 1.0  ±  0.8 (least square estimation, 95 percent confidence level, R 2 between 0.9864 and 0.9876). Despite the possible improvements

  3. Energy Performance of a Novel System Combining Natural Ventilation with Diffuse Ceiling Inlet and Thermally Activated Building Systems (TABS)

    DEFF Research Database (Denmark)

    Yu, Tao

    As a response to new stringent energy policies in the building sector, office buildings have become well-insulated and highly-airtight, resulting in an increasing cooling need in both summer and winter. This study proposes a novel system combining natural ventilation with diffuse ceiling inlet...... and thermally activated building systems (TABS) for cooling and ventilation in future Danish office buildings. The new solution would have the special potential of using natural ventilation all year round even in the extremely cold seasons without any draught risk. The main focuses of this study are the energy...... saving potential and the steady-state and dynamic energy performance of this system. The presented work utilizes building simulation method to investigate the energy saving potential of this novel system. Afterwards, an experimental set-up is built in the laboratory to simulate a real office environment...

  4. Natural ventilation systems to enhance sustainability in buildings: a review towards zero energy buildings in schools

    Directory of Open Access Journals (Sweden)

    Gil-Baez Maite

    2017-01-01

    Full Text Available European regulations set the condition of Zero Energy Buildings for new buildings since 2020, with an intermediate milestone in 2018 for public buildings, in order to control greenhouse gases emissions control and climate change mitigation. Given that main fraction of energy consumption in buildings operation is due to HVAC systems, advances in its design and operation conditions are required. One key element for energy demand control is passive design of buildings. On this purpose, different recent studies and publications analyse natural ventilation systems potential to provide indoor air quality and comfort conditions minimizing electric power consumption. In these passive systems are of special relevance their capacities as passive cooling systems as well as air renovation systems, especially in high-density occupied spaces. With adequate designs, in warm/mild climates natural ventilation systems can be used along the whole year, maintaining indoor air quality and comfort conditions with small support of other heating/cooling systems. In this paper is analysed the state of the art of natural ventilation systems applied to high density occupied spaces with special focus on school buildings. The paper shows the potential and applicability of these systems for energy savings and discusses main criteria for their adequate integration in school building designs.

  5. Natural ventilation systems to enhance sustainability in buildings: a review towards zero energy buildings in schools

    Science.gov (United States)

    Gil-Baez, Maite; Barrios-Padura, Ángela; Molina-Huelva, Marta; Chacartegui, Ricardo

    2017-11-01

    European regulations set the condition of Zero Energy Buildings for new buildings since 2020, with an intermediate milestone in 2018 for public buildings, in order to control greenhouse gases emissions control and climate change mitigation. Given that main fraction of energy consumption in buildings operation is due to HVAC systems, advances in its design and operation conditions are required. One key element for energy demand control is passive design of buildings. On this purpose, different recent studies and publications analyse natural ventilation systems potential to provide indoor air quality and comfort conditions minimizing electric power consumption. In these passive systems are of special relevance their capacities as passive cooling systems as well as air renovation systems, especially in high-density occupied spaces. With adequate designs, in warm/mild climates natural ventilation systems can be used along the whole year, maintaining indoor air quality and comfort conditions with small support of other heating/cooling systems. In this paper is analysed the state of the art of natural ventilation systems applied to high density occupied spaces with special focus on school buildings. The paper shows the potential and applicability of these systems for energy savings and discusses main criteria for their adequate integration in school building designs.

  6. Assessment of dynamic mechanical properties of the respiratory system during high-frequency oscillatory ventilation*.

    Science.gov (United States)

    Dellacà, Raffaele L; Zannin, Emanuela; Ventura, Maria L; Sancini, Giulio; Pedotti, Antonio; Tagliabue, Paolo; Miserocchi, Giuseppe

    2013-11-01

    1) To investigate the possibility of estimating respiratory system impedance (Zrs, forced oscillation technique) by using high-amplitude pressure oscillations delivered during high-frequency oscillatory ventilation; 2) to characterize the relationship between Zrs and continuous distending pressure during an increasing/decreasing continuous distending pressure trial; 3) to evaluate how the optimal continuous distending pressure identified by Zrs relates to the point of maximal curvature of the deflation limb of the quasi-static pressure-volume curve. Prospective laboratory animal investigation. Experimental medicine laboratory. Eight New Zealand rabbits. The rabbits were ventilated with high-frequency oscillatory ventilation. Zrs was measured while continuous distending pressure was increased and decreased between 2 and 26 cm H2O in 1-minute steps of 4 cm H2O. At each step, a low-amplitude (6 cm H2O) sinusoidal signal was alternated with a high-amplitude (18 cm H2O) asymmetric high-frequency oscillatory ventilation square pressure waveform. Pressure-volume curves were determined at the end of the continuous distending pressure trial. All measurements were repeated after bronchoalveolar lavage. Zrs was estimated from flow and pressure measured at the inlet of the tracheal tube and expressed as resistance (Rrs) and reactance (Xrs). Linear correlation between the values, measured by applying the small-amplitude sinusoidal signal and the ventilator waveform, was good for Xrs (r = 0.95 ± 0.04) but not for Rrs (r = 0.60 ± 0.34). Following lavage, the Xrs-continuous distending pressure curves presented a maximum on the deflation limb, identifying an optimal continuous distending pressure that was, on average, 1.1 ± 1.7 cm H2O below the point of maximal curvature of the deflation limb of the pressure-volume curves. Xrs can be accurately measured during high-frequency oscillatory ventilation without interrupting ventilation and/or connecting additional devices. An optimal

  7. Occupational exposure to nitrous oxide - the role of scavenging and ventilation systems in reducing the exposure level in operating rooms.

    Science.gov (United States)

    Krajewski, Wojciech; Kucharska, Malgorzata; Wesolowski, Wiktor; Stetkiewicz, Jan; Wronska-Nofer, Teresa

    2007-03-01

    The aim of this study was to assess the level of occupational exposure to nitrous oxide (N(2)O) in operating rooms (ORs), as related to different ventilation and scavenging systems used to remove waste anaesthetic gases from the work environment. The monitoring of N(2)O in the air covered 35 ORs in 10 hospitals equipped with different systems for ventilation and anaesthetic scavenging. The examined systems included: natural ventilation with supplementary fresh air provided by a pressure ventilation system (up to 6 air changes/h); pressure and exhaust ventilation systems equipped with ventilation units supplying fresh air to and discharging contaminated air outside the working area (more than 10 air changes/h); complete air-conditioning system with laminar air flow (more than 15 air changes/h). The measurements were carried out during surgical procedures (general anaesthesia induced intravenously and maintained with inhaled N(2)O and sevofluran delivered through cuffed endotracheal tubes) with connected or disconnected air scavenging. Air was collected from the breathing zone of operating personnel continuously through the whole time of anaesthesia to Tedlar((R)) bags, and N(2)O concentrations in air samples were analyzed by adsorption gas chromatography/mass spectrometry. N(2)O levels in excess of the occupational exposure limit (OEL) value of 180mg/m(3) were registered in all ORs equipped with ventilation systems alone. The OEL value was exceeded several times in rooms with natural ventilation plus supplementary pressure ventilations and twice or less in those with pressure/exhaust ventilation systems or air conditioning. N(2)O levels below or within the OEL value were observed in rooms where the system of air conditioning or pressure/exhaust ventilation was combined with scavenging systems. Systems combining natural/pressure ventilation with scavenging were inadequate to maintain N(2)O concentration below the OEL value. Air conditioning and an efficient pressure

  8. Airtightness and ventilation system performance of apartments in new multi-unit residential buildings

    Energy Technology Data Exchange (ETDEWEB)

    Cooke, G. [Air Solutions Inc., Toronto, ON (Canada); Kokko, J.; Greene, T. [Enermodal Engineering Ltd., Kitchener, ON (Canada)

    2005-07-01

    There are growing concerns that conventional air handling systems in apartment buildings cannot ventilate individual apartments, are expensive in terms of initial cost and maintenance, have little impact on indoor air quality, and negatively impact the integrity of fire and smoke control separations. This paper discusses the strategy of compartmentalizing individual apartments to eliminate uncontrolled air movement as well as providing efficient and effective ventilation in each suite. The findings of recent air leakage testing and ventilation system performance testing in several recently constructed high-rise buildings were documented in this paper. Results indicated that compartmentalization was a viable strategy. However, ventilation strategies for both common corridors and apartments required adjustments. Air leakage testing showed that individual apartments were relatively airtight. However, concerns were raised that continuous negative pressure could induce water leakage through the building envelope. Testing also discovered that airflow capacities of in-suite exhaust equipment was less than manufacturer's specifications. Duct lengths, diameters, fittings, elbows and termination details had an impact on airflow performance. Testing also confirmed that the corridor ventilation systems were not energy efficient as a significant amount of outdoor air was required to pressurize leaks in the corridors and to ensure sufficient air was available to make-up air requirements in each apartment in response to intermittent exhaust fan operation. It was also determined that a very small positive pressure was required to accomplish the task of pressurizing corridors to minimize odour transmission. The provision of weather-stripping on corridor to apartment doors would reduce the quantity of airflow required for pressurization, helping to prevent shifts in pressure due to opening doors, elevators and wind and stack pressures acting in varying ways. 8 refs., 4 tabs., 2

  9. Ventilation Criteria for Aeromedical Evacuation.

    Science.gov (United States)

    1986-09-01

    number) FIELD GROUP i SUB-GROUP Aeromedical evacuation; Ventilatory requirements; 06 11 06 12 iAir evacuation; and Mechanical ventilation . 19...ABSTRACT (Continue on reverse if necessary and identify by block number) -., fr evacLation of patients requiring mechanical ventilation exposes these...reasonably stable from a medical standpoint; none required mechanical ventilation . Unfortunately, we find no .- , studies that describe the

  10. Advanced Hybrid Spacesuit Concept Featuring Integrated Open Loop and Closed Loop Ventilation Systems

    Science.gov (United States)

    Daniel, Brian A.; Fitzpatrick, Garret R.; Gohmert, Dustin M.; Ybarra, Rick M.; Dub, Mark O.

    2013-01-01

    A document discusses the design and prototype of an advanced spacesuit concept that integrates the capability to function seamlessly with multiple ventilation system approaches. Traditionally, spacesuits are designed to operate both dependently and independently of a host vehicle environment control and life support system (ECLSS). Spacesuits that operate independent of vehicle-provided ECLSS services must do so with equipment selfcontained within or on the spacesuit. Suits that are dependent on vehicle-provided consumables must remain physically connected to and integrated with the vehicle to operate properly. This innovation is the design and prototype of a hybrid spacesuit approach that configures the spacesuit to seamlessly interface and integrate with either type of vehicular systems, while still maintaining the ability to function completely independent of the vehicle. An existing Advanced Crew Escape Suit (ACES) was utilized as the platform from which to develop the innovation. The ACES was retrofitted with selected components and one-off items to achieve the objective. The ventilation system concept was developed and prototyped/retrofitted to an existing ACES. Components were selected to provide suit connectors, hoses/umbilicals, internal breathing system ducting/ conduits, etc. The concept utilizes a lowpressure- drop, high-flow ventilation system that serves as a conduit from the vehicle supply into the suit, up through a neck seal, into the breathing helmet cavity, back down through the neck seal, out of the suit, and returned to the vehicle. The concept also utilizes a modified demand-based breathing system configured to function seamlessly with the low-pressure-drop closed-loop ventilation system.

  11. A Bayesian decision-support system for diagnosing ventilator-associated pneumonia

    OpenAIRE

    Schurink, C.A.; Visscher, S.; Lucas, P.J.; van Leeuwen, H.J.; Buskens, E.; Hoff, R.G.; Hoepelman, A.I.; Bonten, M.J.

    2007-01-01

    OBJECTIVE: To determine the diagnostic performance of a Bayesian Decision-Support System (BDSS) for ventilator-associated pneumonia (VAP). DESIGN: A previously developed BDSS, automatically obtaining patient data from patient information systems, provides likelihood predictions of VAP. In a prospectively studied cohort of 872 ICU patients, VAP was diagnosed by two infectious-disease specialists using a decision tree (reference diagnosis). After internal validation daily BDSS predictions were ...

  12. Alternative ventilation system for operating theaters: parameter study and full-scale assessment of the performance of a local ventilation system

    NARCIS (Netherlands)

    J.G.H. Loogman; Dr. H.S.M. Kort; I.M. de Visser; M.G.L.C. Loomans

    2016-01-01

    A local operating theater ventilation device to specifically ventilate the wound area has been developed and investigated. The ventilation device is combined with a blanket which lies over the patient during the operation. Two configurations were studied: Configuration 1 where HEPA-filtered air was

  13. A novel simulator for mechanical ventilation in newborns: MEchatronic REspiratory System SImulator for Neonatal Applications.

    Science.gov (United States)

    Baldoli, Ilaria; Cuttano, Armando; Scaramuzzo, Rosa T; Tognarelli, Selene; Ciantelli, Massimiliano; Cecchi, Francesca; Gentile, Marzia; Sigali, Emilio; Laschi, Cecilia; Ghirri, Paolo; Menciassi, Arianna; Dario, Paolo; Boldrini, Antonio

    2015-08-01

    Respiratory problems are among the main causes of mortality for preterm newborns with pulmonary diseases; mechanical ventilation provides standard care, but long-term complications are still largely reported. In this framework, continuous medical education is mandatory to correctly manage assistance devices. However, commercially available neonatal respiratory simulators are rarely suitable for representing anatomical and physiological conditions; a step toward high-fidelity simulation, therefore, is essential for nurses and neonatologists to acquire the practice needed without any risk. An innovative multi-compartmental infant respirator simulator based on a five-lobe model was developed to reproduce different physio-pathological conditions in infants and to simulate many different kinds of clinical scenarios. The work consisted of three phases: (1) a theoretical study and modeling phase, (2) a prototyping phase, and (3) testing of the simulation software during training courses. The neonatal pulmonary simulator produced allows the replication and evaluation of different mechanical ventilation modalities in infants suffering from many different kinds of respiratory physio-pathological conditions. In particular, the system provides variable compliances for each lobe in an independent manner and different resistance levels for the airway branches; moreover, it allows the trainer to simulate both autonomous and mechanically assisted respiratory cycles in newborns. The developed and tested simulator is a significant contribution to the field of medical simulation in neonatology, as it makes it possible to choose the best ventilation strategy and to perform fully aware management of ventilation parameters. © IMechE 2015.

  14. Comparison of indoor air distribution and thermal environment for different combinations of radiant heating systems with mechanical ventilation systems

    DEFF Research Database (Denmark)

    Wu, Xiaozhou; Fang, Lei; Olesen, Bjarne W.

    2018-01-01

    air distribution and the thermal environment for all combinations of radiant heating systems with mechanical ventilation systems. Therefore, in this article, the indoor air distribution and the thermal environment were comparatively analyzed in a room with floor heating (FH) or ceiling heating (CH...

  15. Energy saving effect of desiccant ventilation system using Wakkanai siliceous shale

    Science.gov (United States)

    Nabeshima, Yuki; Togawa, Jun-ya; Nagano, Katsunori; Kazuyo, Tsuzuki

    2017-10-01

    The nuclear power station accident resulting from the Great East Japan Earthquake disaster has resulted in a constrained electricity supply. However, in this Asian region there is high temperature and high humidity and consequently dehumidification process requires a huge amount of energy. This is the reason for the increasing energy consumption in the residential and commercial sectors. Accordingly, a high efficiency air-conditioning system is needed to be developed. The desiccant ventilation system is effective to reduce energy consumption for the dehumidification process. This system is capable of dehumidifying without dew condensing unlike a conventional air-conditioning system. Then we focused on Wakkanai Siliceous Shale (WSS) as a desiccant material to develop a new desiccant ventilation system. This is low priced, high performance, new type of thing. The aim of this study is to develop a desiccant ventilation unit using the WSS rotor which can be regenerated with low-temperature by numerical calculation. The results of performance prediction of the desiccant unit, indicate that it is possible to regenerate the WSS rotor at low-temperature of between 35 - 45 °C. In addition, we produced an actual measurement for the desiccant unit and air-conditioning unit. This air-conditioning system was capable to reduce roughly 40 % of input energy consumption.

  16. Performance of a demand controlled mechanical extract ventilation system for dwellings

    Directory of Open Access Journals (Sweden)

    I. Pollet

    2013-10-01

    Full Text Available The main aim of ventilation is to guarantee a good indoor air quality, related to the energy consumed for heating and fan(s. Active or passive heat recovery systems seem to focus on the reduction of heating consumption at the expense of fan electricity consumption and maintenance. In this study, demandcontrolled mechanical extract ventilation systems of Renson (DCV1 and DCV2, based on natural supply in the habitable rooms and mechanical extraction in the wet rooms (or even the bedrooms, was analysed for one year by means of multi-zone Contam simulations on a reference detached house and compared with standard MEV and mechanical extract ventilation systems with heat recovery (MVHR. To this end, IAQ, total energy consumption, CO2 emissions and total cost of the systems are determined. The results show that DCV systems with increased supply air flow rates or direct mechanical extract from bedrooms can significantly improve IAQ, while reducing total energy consumption compared to MEV. Applying DCV reduces primary heating energy consumption and yearly fan electricity consumption at most by 65% to 50% compared to MEV. Total operational energy costs and CO2 emissions of DCV are similar when compared to MVHR. Total costs of DCV systems over 15 years are smaller when compared to MVHR due to lower investment and maintenance costs.

  17. Personalized ventilation

    DEFF Research Database (Denmark)

    Melikov, Arsen Krikor

    2004-01-01

    The thermal environment and air quality in buildings affects occupants' health, comfort and performance. The heating, ventilating and air-conditioning (HVAC) of buildings today is designed to provide a uniform room environment. However, large individual differences exist between occupants in regard...... microenvironment. Furthermore, HVAC systems should be designed to protect occupants from airborne transmission of infectious agents that may be present in exhaled air. Personalized ventilation is a new development in the field of HVAC and has the potential to fulfill the above requirements. This paper reviews...... existing knowledge on performance of personalized ventilation (PV) and on human response to it. The airflow interaction in the vicinity of the human body is analyzed and its impact on thermal comfort and inhaled air quality is discussed together with control strategies and the application of PV in practice...

  18. Designing, Constructing and Installing a Local Exhaust Ventilation System to Minimize Welders\\' Exposure to Welding Fumes

    Directory of Open Access Journals (Sweden)

    Sajad Zare

    2017-10-01

    Full Text Available Background & Aims of the Study: Welder’s exposure to welding fumes can cause occupational diseases. The current study sought to examine exposure to welding fumes among welders who work in the repair shop of Sarcheshmeh Copper Complex and design a local exhaust ventilation system to control exposure to welding fumes. Materials & Methods: This applied analytical study was conducted in the summer of 2016 among welders working in the repair shop of Sarcheshmeh Copper Complex. The study comprised three phases; in the first one, welders’ exposure to welding fumes was assessed at the beginning of the study. After that, a local exhaust ventilation system was designed and installed in the aforementioned repair shop. In the final stage, welders’ exposure to welding fumes was assessed again after installation of the ventilation system. The procedure recommended by NIOSH (method number 7300 was used for individual sampling of welders. Results: Based on the obtained findings, before installing the ventilation system, welding technicians were exposed to 0.3 mg/m3 of copper fumes and 0.04 mg/m3 of chromium fumes. Journeyman welders were also exposed to 2.16 mg/m3 of manganese fumes, while stellar welders were exposed to 6.9 mg/m3 of iron fumes. In the light of these measurements, a local exhaust ventilation system was designed and installed. Subsequently, measurement of exposure to welding fumes showed a significant reduction. That is, welding technicians were exposed to 0.17 mg/m3 and 0.015 mg/m3 of copper and chromium fumes respectively. Additionally, journeyman welders were exposed to 0.86 mg/m3 of manganese fumes, whereas stellar welders were exposed to 4.3 mg/m3 of iron fumes. Conclusions: A comparison of standard limits of exposure to welding fumes and the results obtained from measurements in sampling stations before and after the installation of the local exhaust ventilation system reveals that this controlling measure was very effective in the

  19. Control System Implementation and Follow-up within the Cooling and Ventilation Contracts for the LHC

    CERN Document Server

    Body, Y; Morodo, M C

    2001-01-01

    The control system implementation for the cooling and ventilation facilities connected to the LHC Project relies on the technical and human resources that are organised within large-size industrial contracts. Beside the technical aspects, the follow-up of the implementation activities in the framework of such contracts also involves a managerial effort in order to achieve a flexible and coherent control system. The purpose is to assure precise and reliable regulation together with accurate local and remote supervision in conformity with the operational requirements. These objectives can only be reached by a systematic approach that keeps the co-ordination between the in-house and external cross-disciplinary teams as well as the fulfilment of the validation procedures and the contractual formalities. The case that here illustrates this approach is the control system implementation for the heating, ventilation and air conditioning of the LHC surface buildings, which shall extend up to 2004.

  20. An assessment of a partial pit ventilation system to reduce emission under slatted floor

    DEFF Research Database (Denmark)

    Wu, Wentao; Zhang, Guoqiang; Bjerg, Bjarne Schmidt

    2012-01-01

    CFD simulations were carried out to assess the feasibility of using RANS (Reynolds – averaged Navier– Stokes) turbulence models to evaluate the performance of a partial pit ventilation system to reduce gas emission under slatted floor. The entire system included a pit model with slatted floor...... and pit exhaust system, a wind table to simulate ground and a wind tunnel to simulate room space of a naturally ventilated livestock house. CFD simulations started with the selection of a proper domain. Two domains were chosen to evaluate the effect of domain simplification. The results showed...... mechanism of pollutant through slatted floor, vertical mean and turbulent flux were defined and calculated. It was found that turbulence diffusion dominates the transportation of pollutant from the pit headspace into the free stream. Although discrepancies existed for some conditions, good agreements...

  1. Searching for stable orbits in the HD 10180 planetary system

    Directory of Open Access Journals (Sweden)

    Laskar J.

    2011-02-01

    Full Text Available A planetary system with at least seven planets has been found around the star HD 10180. However, the traditional Keplerian and n-body fits to the data provide an orbital solution that becomes unstable very quickly, which may quest the reliability of the observations. Here we show that stable orbital configurations can be obtained if general relativity and long-term dissipation raised by tides on the innermost planet are taken into account.

  2. Stable Nuclear Transformation System for the Coccolithophorid Alga Pleurochrysis carterae

    OpenAIRE

    Hirotoshi Endo; Megumi Yoshida; Toshiki Uji; Naotsune Saga; Koji Inoue; Hiromichi Nagasawa

    2016-01-01

    Of the three dominant marine microalgal groups, dinoflagellates and diatoms can undergo genetic transformation; however, no transformation method has been established for haptophytes to date. Here, we report the first stable genetic transformation of a coccolithophore, Pleurochrysis carterae, by means of polyethylene glycol (PEG)-mediated transfer of a bacterial hygromycin B-resistance gene. Together with the novel transient green fluorescent protein (GFP) expression system, this approach sho...

  3. On the thermal interaction of building structure and heating and ventilation system

    Science.gov (United States)

    Hensen, Joannes Laurentius Maria

    Developments in the field of building performance evaluation tools for thermal interaction of building structure and heating and ventilating systems are described. The technique employed is computer simulation of the integrated dynamic system comprising the occupants, the building and its heating and ventilating system. Assessment criteria from a literature review in thermal comfort to examine acceptable fluctuations in indoor climate are defined. Building and plant energy simulation within the context of Computer Aided Building Design (CABD) is described. An exisiting energy simulation environment ESP(R) (Environmental Systems Performance (Research version)) is chosen. A fluid flow network simulation module is described. Extensions to ESP(R) to predict the dynamic behavior of the heating and ventilation system are described. The coupling of fluid flow, plant side energy and mass, and building side energy simulation into one integrated program is described. A multistage verification and validation methodology is demonstrated by examples addressing each successive step. Imaginary and real world cases are described to demonstrate application of the study in a modeling orientated and a building engineering context.

  4. Performance potential of mechanical ventilation systems with minimized pressure loss

    DEFF Research Database (Denmark)

    Terkildsen, Søren; Svendsen, Svend

    2013-01-01

    simulations that quantify fan power consumption, heating demand and indoor environmental conditions. The system was designed with minimal pressure loss in the duct system and heat exchanger. Also, it uses state-of-the-art components such as electrostatic precipitators, diffuse ceiling inlets and demand...

  5. Design and simulation of a hybrid ventilation system with earth-air heat exchanger

    Energy Technology Data Exchange (ETDEWEB)

    Athienitis, A.K.; Zhao, M. [Concordia Univ., Centre for Building Studies, Montreal, PQ (Canada). Dept. of Building, Civil and Environmental Engineering; Roy, M. [Martin Roy and Associes Group Conseil Inc., Montreal, PQ (Canada)

    2005-07-01

    A simulation study was conducted during the design phase of a new circus building in Montreal which includes a hybrid ventilation system through which fresh air is supplied from an earth-air heat exchanger (EAHE). The EAHE has the potential to satisfy the cooling needs of the building and can also be used to preheat fresh air, thereby satisfying one-third or more of the building's heating needs. Another feature of the building is that it uses displacement ventilation by which the air is supplied at low velocities through large diffusers behind the top level seats or under the seats. In this study, computational fluid dynamics (CFD) simulations were carried out to help size the supply and return units of the heating, ventilating and air conditioning (HVAC) system, as well as the exhaust chimney. The primary objective of the CFD simulation was to determine the maximum velocity and temperature in the seated area to ensure thermal comfort. CFD simulation predictions were found to be in good agreement with preliminary measurements taken in the building. In order to monitor the operation of the system over the next year, the underground ducts were equipped with temperature sensors at several depths into the soil. The energy efficiency of the hybrid HVAC system will be assessed and the velocity and temperature distribution in the theatre will be examined under various operating and energy load conditions. 8 refs., 6 figs.

  6. Cost optimization for buildings with hybrid ventilation systems

    Energy Technology Data Exchange (ETDEWEB)

    Ji, Kun; Lu, Yan

    2018-02-13

    A method including: computing a total cost for a first zone in a building, wherein the total cost is equal to an actual energy cost of the first zone plus a thermal discomfort cost of the first zone; and heuristically optimizing the total cost to identify temperature setpoints for a mechanical heating/cooling system and a start time and an end time of the mechanical heating/cooling system, based on external weather data and occupancy data of the first zone.

  7. Ventilator Data Extraction with a Video Display Image Capture and Processing System.

    Science.gov (United States)

    Wax, David B; Hill, Bryan; Levin, Matthew A

    2017-06-01

    Medical hardware and software device interoperability standards are not uniform. The result of this lack of standardization is that information available on clinical devices may not be readily or freely available for import into other systems for research, decision support, or other purposes. We developed a novel system to import discrete data from an anesthesia machine ventilator by capturing images of the graphical display screen and using image processing to extract the data with off-the-shelf hardware and open-source software. We were able to successfully capture and verify live ventilator data from anesthesia machines in multiple operating rooms and store the discrete data in a relational database at a substantially lower cost than vendor-sourced solutions.

  8. EVALUATION OF BEST AVAILABLE CONTROL TECHNOLOGY FOR TOXICS -TBACT- DOUBLE SHELL TANK FARMS PRIMARY VENTILATION SYSTEMS SUPPORTING WASTE TRANSFER OPERATIONS

    Energy Technology Data Exchange (ETDEWEB)

    HAAS CC; KOVACH JL; KELLY SE; TURNER DA

    2010-06-24

    This report is an evaluation of Best Available Control Technology for Toxics (tBACT) for installation and operation of the Hanford double shell (DST) tank primary ventilation systems. The DST primary ventilation systems are being modified to support Hanford's waste retrieval, mixing, and delivery of single shell tank (SST) and DST waste through the DST storage system to the Waste Treatment and Immobilizaiton Plant (WTP).

  9. EVALUATION OF BEST AVAILABLE CONTROL TECHNOLOGY FOR TOXICS (TBACT) DOUBLE SHELL TANK FARMS PRIMARY VENTILATION SYSTEM SUPPORTING WASTE TRANSFER OPERATIONS

    Energy Technology Data Exchange (ETDEWEB)

    KELLY SE; HAASS CC; KOVACH JL; TURNER DA

    2010-06-03

    This report is an evaluation of Best Available Control Technology for Toxics (tBACT) for installation and operation of the Hanford double shell (DST) tank primary ventilation systems. The DST primary ventilation systems are being modified to support Hanford's waste retrieval, mixing, and delivery of single shell tank (SST) and DST waste throught the DST storage system to the Waste Treatment and Immobilization Plant (WTP).

  10. Assessment of buildings with ventilated facade systems and evaluation of point thermal bridges

    OpenAIRE

    Šadauskienė, Jolanta; Šeduikytė, Lina; Juozas RAMANAUSKAS; Buska, Andrius

    2017-01-01

    Analyzes of influence of the point thermal bridges of buildings with ventilated facade systems on the thermal properties of envelops are presented in the paper. The relation between the separate components of the envelop were made: thermal properties and thickness of supporting wall's layer; value of thermal conductivity and thickness of insulation layer. Studies have shown, that the value of the point thermal transmittance, which depended on the thermal properties of the envelop and thicknes...

  11. Plan of action for quality improvement of ventilation systems; Actieplan Kwaliteitsverbetering Ventilatievoorzieningen

    Energy Technology Data Exchange (ETDEWEB)

    Atsma, J. [Ministerie van Infrastructuur en Milieu IenM, Den Haag (Netherlands); Calon, M. [Aedes vereniging van woningcorporaties, Den Haag (Netherlands); Schoorl, F.J. [Bond Nederlandse Architecten BNA, Amsterdam (Netherlands); Van Tuinen, J.L. [Bouwend Nederland, Zoetermeer (Netherlands); Bodewes, W.J. [Vereniging van Nederlandse projectontwikkeling Maatschappijen Neprom, Voorburg (Netherlands); Goossens, J.H. [Vereniging voor ontwikkelaars en bouwondernemers NVB, Voorburg (Netherlands); Polman, E.J.M. [Stichting Waarborgfonds Koopwoningen SWK, Rotterdam (Netherlands); Engels, M. [Uneto-VNI, Zoetermeer (Netherlands); Werner-van Beek, H. J. [VACpunt Wonen, Utrecht (Netherlands); Mulder, R.J. [Vereniging Eigen Huis VEH, Amersfoort (Netherlands); Rook, G. [Vereniging Leveranciers van Luchttechnische Apparaten VLA, Zoetermeer (Netherlands); Van Noord, P. [Woningborg, Gouda (Netherlands); Paping, R.H.M. [De Nederlandse Woonbond, Amsterdam (Netherlands)

    2012-06-15

    The action plan comprises the agreements made by the Ministry of Infrastructure and Environment and the Ministry of Internal Affairs in the Netherlands with representatives of building organizations to improve the quality of ventilation systems in newly built houses [Dutch] Het actieplan bevat de afspraken die het ministerie van Infrastructuur en Milieu en het ministerie van Binnenlandse Zaken met de bouwpartijen hebben gemaakt om de kwaliteit van de ventilatievoorzieningen van nieuwbouwwoningen te verbeteren.

  12. State of Lipid Peroxidation and Antioxidant Defense System in Newborns Requiring Artificial Lung Ventilation

    OpenAIRE

    Kh.B. Slivinska-Kurchak; Yu.S. Korzhynsky; Ya.M. Mykytyn; O.M. Fitsala

    2013-01-01

    The article deals with studying indicators of lipid peroxidation (TBA-active products, lipid hydroperoxides, diene conjugates) and antioxidant defense (superoxide dismutase, glutathione peroxidase, vitamins A and E) in the blood of newborns on synchronized intermittent ventilation with pressure support and spontaneous breathing with continuous positive airway pressure via nasal cannula. The results show a more significant activation of lipid peroxidation system in newborns on synchronized int...

  13. Existing Whole-House Solutions Case Study: Multifamily Individual Heating and Ventilation Systems, Lawrence, Massachusetts

    Energy Technology Data Exchange (ETDEWEB)

    None

    2013-11-01

    The conversion of an older Massachusetts building into condominiums illustrates a safe, durable, and cost-effective solution for heating and ventilation systems that can potentially benefit millions of multifamily buildings. In this project, Merrimack Valley Habitat for Humanity (MVHfH) partnered with U.S. Department of Energy Building America team Building Science Corporation (BSC) to provide high performance affordable housing for 10 families in the retrofit of an existing mass masonry building (a former convent).

  14. Use of VOC sensors for air quality control of building ventilation systems

    OpenAIRE

    Großklos, M.

    2015-01-01

    Air quality control with VOC (volatile organic compound) sensors in residential buildings could increase user comfort by adapting to the actual contaminant level. Preliminary tests assessed the dynamics of VOC levels in single-family passive houses with a ventilation system. At normal and exceptional usages, sufficient signal variations were measured for air quality control. An air quality control was developed and tested in four single-family passive house dwellings to cont...

  15. A Novel In-Line Delivery System to Administer Dry Powder Mannitol to Mechanically Ventilated Patients.

    Science.gov (United States)

    Feng, Benny; Tang, Patricia; Leung, Sharon Shui Yee; Dhanani, Jayesh; Chan, Hak-Kim

    2017-04-01

    Mechanically ventilated patients commonly suffer from ventilator-associated pneumonia, hypoxemia, and other lower respiratory tract infection as a result of pathogen colonization and poor sputum clearance. Consequently, there is a high rate of morbidity and mortality in these patients. Dry powder mannitol increases sputum clearance, and therefore, we developed a system to administer it to mechanically ventilated patients without disconnection from the ventilator. The inspiratory line from a ventilator was split by using a three-way valve into two parallel lines where one contains a humidifier for normal breathing cycle and the other line contains a dry powder inhaler (Osmohaler™). The inspiratory air went through the dry powder line and aerosolized the mannitol powder only when its administration to a patient is required. We determined the delivered dose and particle size distributions of emitted aerosols in vitro from 9.5 mm endotracheal and 7.5 mm tracheostomy tubes, with inspiratory airflow of 60, 70, and 80 L/min. This novel setup was able to deliver 24.6% ± 3.33% of the 160 mg loaded dose mannitol powder (4 × 40 mg capsules) and 26.7% ± 2.19% of the 320 mg dose (4 × 80 mg capsules) when the endotracheal tube was used. With the shorter tracheostomy tube, the delivery dose increased to 35.6% ± 3.01% and 39.5% ± 2.04% of the 160 and 320 mg doses, respectively. The volume median diameters of the aerosols were in the respirable range with the largest value being 5.17 ± 0.87 μm. This delivery system has been shown to consistently deliver a high respirable dose of mannitol powder. Since this setup does not require disconnection of patients from the ventilator, it is safer for hypoxemic patients and easier to be adapted in a real clinical use.

  16. Flow change in a mine ventilation system with diagonal branch connections due to variations in aerodynamic resistances during transient regimes

    Energy Technology Data Exchange (ETDEWEB)

    Vuletic, V.

    1981-01-01

    The paper deals with investigations of parameters of ventilation systems affecting flow changes due to variations in the resistances in individual branches. The problem was studied on an analog computer.

  17. Correlation between germ and particle measurements for the qualification of ventilation systems in the OR

    Directory of Open Access Journals (Sweden)

    Bulitta Clemens

    2017-09-01

    Full Text Available Healthcare associated infections in surgical procedures have long been the focus of scientific research. In Germany, more than 225,000 patients suffer from such infections each year [1]. However, the reduction of the microbiological contamination is not only limited by cleaning and disinfecting measures. The choice of the ventilation system in the operating room or the type of the clothing of the personnel during the operation is also an important factor contributing to patient safety and infection control. Currently there are different approaches for assessing the hygienic situation in an operating room. In Germany, the air quality and cleanliness is evaluated by the DIN 1946-4: 2008-12 [2] and is based on the measurement of particles in the operating theatre. Other countries i.eSweden. focus on the biological contamination and use microbiological methods for the assessment and surveillance of the operating room ventilation (SIS-TS 39: 2015 [3].

  18. Dispersion of Exhalation Pollutants in a Two-bed Hospital Ward with a Downward Ventilation System

    DEFF Research Database (Denmark)

    Qian, Hua; Nielsen, Peter V.; Hyldgård, Carl-Erik

    2006-01-01

    The Centers for Disease Control and Prevention has recommended the use of downward ventilation systems in isolation rooms to reduce the risk of cross-infection from airborne transmissible diseases. The expected airflow pattern of a downward ventilation design would supply cooler and slightly...... heavier clean air from a ceiling diffuser to push down contaminants, which would then be removed via outlets at floor level. A "laminar" (strictly speaking, unidirectional) flow is expected to be produced to avoid flow mixing and thus reduce cross-infection risk. Experiments were carried out in a full...... to investigate the airflow pattern and pollutant dispersion in the test ward. Based on both experimental and numerical results, the laminar airflow pattern was shown to be impossible to achieve due to turbulent flow mixing and flow entrainment into the supply air stream. The thermal plumes produced above people...

  19. Numerical analysis of natural ventilation system in a studio apartment in Bangladesh

    Science.gov (United States)

    Kabir, K. M. Ariful; Hasan, Md. Rakibul; Khan, Md. Abdul Hakim

    2017-07-01

    The study of temperature and air flow for natural ventilation system has been investigated numerically. A finite element model for studio apartment was developed with the aim of achieving detail energy allocation in the real buildings during the transient process in the walls and internal air. A tool of computational fluid dynamics (CFD) is employed to assist the process. In the tropical regions most of the energy is consumed by the heating, cooling and ventilation appliances. Therefore, the optimize ventilation system will be a suitable and valid option for the saving of energy from the household sector to increase cooling performance and ensuring thermal comfort as well. A mathematical exploration is carried out on full scale dwelling and small scale model and indication is given on the relevance of such a comparison. Calculations are carried out with household heat sources for calm and windy period, but without any human. As expected, for windy periods, the wind is the main driving force behind the internal air flow. However, in calm periods for unsteady flow the internal airflow looks like more complexes through observation.

  20. Design Principles for Natural and Hybrid Ventilation

    DEFF Research Database (Denmark)

    Heiselberg, Per

    For many years mechanical and natural ventilation systems have developed separately. Naturally, the next step in this development is the development of ventilation concepts that utilize and combine the best features from each system to create a new type of ventilation system- Hybrid Ventilation. ....... The hybrid ventilation concepts, design challenges and principles are discussed and illustrated by four building examples....

  1. Design Principles for Natural and Hybrid Ventilation

    OpenAIRE

    Heiselberg, Per

    2000-01-01

    For many years mechanical and natural ventilation systems have developed separately. Naturally, the next step in this development is the development of ventilation concepts that utilize and combine the best features from each system to create a new type of ventilation system- Hybrid Ventilation. The hybrid ventilation concepts, design challenges and principles are discussed and illustrated by four building examples.

  2. [A design of simple ventilator control system based on LabVIEW].

    Science.gov (United States)

    Pei, Baoqing; Xu, Shengwei; Li, Hui; Li, Deyu; Pei, Yidong; He, Haixing

    2011-01-01

    This paper designed a ventilator control system to control proportional valves and motors. It used LabVIEW to control the object mentioned above and design ,validate, evaluate arithmetic, and establish hardware in loop platform. There are two system' s hierarchies. The high layer was used to run non-real time program and the low layer was used to run real time program. The two layers communicated through TCP/IP net. The program can be divided into several modules, which can be expanded and maintained easily. And the harvest in the prototype designing can be seamlessly used to embedded products. From all above, this system was useful in employing OEM products.

  3. Physicochemical Characterization of Nanoparticles from Indoor Ventilation Systems and Their Potential Health Impacts

    Science.gov (United States)

    Dalton, G.; Revkin, A. C.; Gruenspecht, H.; Ramanathan, V.; Brown, M. A.; Nagel, D. C.; Revkin, A. C.; Umo, N. S.; Oseghe, E. O.

    2016-12-01

    Indoor air pollution remains a major concern to humans considering that we spend about 90% of our daily lives indoors [1,2]. Air pollutants, which ranges from gases to aerosol particles, vary considerably from our homes, public/work places and confined environments such as cars. They can impact on our health depending on the nature and concentration of the pollutants as well as the duration of exposure [3,4]. Particulate matter (PM), which is one of the major air pollutant markers, is present indoors and can be circulated for days to months within a confined space by the ventilation systems. In this study, both physical and chemical compositional evaluation of PM2.5 - 10 was carried out and the recirculation model of these particulates is presented based on the study of some ventilation systems such as air conditioners, cooling vents, and fans. For the first time, it is shown that the compositional variability of PM does not just depend on the source or the ongoing activities in the confined space but also on the recirculation time. Mineral dust particles were found to be dominant, some mixed with organics and soot or BC particles; heavy metals such as lead (Pb), cadmium (Cd), nickel (Ni), iron (Fe) and others were also analysed from the collected PM. Ventilation systems trap these particulates and do recirculate them over time and this can increase their toxicities and influences their composition. From this study, it can be suggested that regular cleaning of ventilation systems and flushing closed spaces with fresh air may become the most effective ways of controlling the concentration of PM in closed spaces with ventilation units such as indoors and cars. [1] H. K. Lai, et al., Atmospheric Environment 38 (37)(2004). [2] N.E. Klepeis, et al., J. of Exposure Analysis and Environmental Epidemiology 11(2001). [3] N. Bruce, et al., Bul. of the World Health Organization, 78 (9)(2000). [4] K.A. Miller, et al, The New England Journal of Medicine 356 (2007).

  4. Dispersion of exhaled droplet nuclei in a two-bed hospital ward with three different ventilation systems

    DEFF Research Database (Denmark)

    Qian, H.; Li, Y.; Nielsen, Peter V.

    2006-01-01

    hospital ward with three ventilation systems, i.e. mixing, downward and displacement ventilation. Two life-size breathing thermal manikins were used to simulate a source patient and a receiving patient. The exhalation jet from a bed-lying manikin was visualized using smoke. N2O was used as tracer gas......Effective ventilation in general hospital wards is important for controlling the airborne transmission of infectious respiratory diseases. Experiments have been carried out to increase our understanding of the interaction of the breathing flows of two individuals in a full-scale experimental...

  5. Ventilator waveform interpretation in mechanically ventilated small animals.

    Science.gov (United States)

    Corona, Terry M; Aumann, Marcel

    2011-10-01

    To review the topic of ventilator waveforms analysis with emphasis on interpretation of ventilator waveforms and their use in the management and monitoring of mechanically ventilated small animal patients. Human clinical studies, scientific reviews, and textbooks, as well as veterinary textbooks and clinical examples of ventilator waveforms in mechanically ventilated dogs. Ventilator waveforms are graphic representations of data collected from the ventilator and reflect patient-ventilator interactions. The 4 parameters pressure, volume, flow, and time are most descriptive of mechanical ventilation. Typically, 3 different graphs, also referred to as scalars, consisting of pressure versus time, volume versus time, and flow versus time, with time always plotted on the x-axis, are used. Changes in the ventilator settings as well as in the characteristics of the lungs such as airway resistance (R(aw)) and respiratory system compliance (C(rs)) can be recognized from specific variations in the waveforms. Flow-volume and pressure-volume loops provide additional information about changes in lung function. Patient-ventilator dyssynchrony is a common problem during mechanical ventilation and can lead to patient discomfort and an increased work of breathing. Ventilator waveforms are helpful to identify dyssynchrony, which can be divided into trigger, flow, cycle, and expiratory dyssynchrony. Ventilator waveforms allow the clinician to assess changes in respiratory mechanics, and can be useful in monitoring the progression of disease pathology and response to therapy. Adjustments in ventilator settings based on proper analysis and interpretation of these waveforms can help the clinician to optimize ventilation therapy. Ventilator waveforms are graphic representations of patient-ventilator interactions. Proper interpretation of ventilator waveforms affords the critical care clinician a better understanding of the patient's respiratory function, response to therapy, and causes

  6. Numerical Study on Different Series Modes of Jet Fan in a Longitudinal Tunnel Ventilation System

    Directory of Open Access Journals (Sweden)

    Guihong Pei

    2014-01-01

    Full Text Available Efficient ventilation systems will contribute to maintaining air quality in the tunnel. In order to improve ventilation performance in normal traffic condition, the 3D tunnel models were established according to the original design for the tunnel located in central plains of China. Based on the commercial CFD software Fluent 6.3 and k-ε turbulence model, numerical simulations were carried out to study the patterns of jet flow and the optimization of fan combinations. It is found that the axial velocity profile obtained from numerical simulation agrees quite well with turbulent free jet theory although there is a little difference on the magnitude. The comparison of four combination modes under the condition of operating four fans indicates that the ventilation effectiveness is affected mainly by both the interval of adjacent groups of fans and the combination modes of operational fans. According to the simulation results, a novel combination mode which consists of a group double paralleled fans and two groups single fan is designed. The novel combination mode is regarded as the optimum combination mode with respect to maximizing air velocity in the tunnel. Compared to the traditional combination modes, it will increase the air velocity by 5.7%.

  7. State of Lipid Peroxidation and Antioxidant Defense System in Newborns Requiring Artificial Lung Ventilation

    Directory of Open Access Journals (Sweden)

    Kh.B. Slivinska-Kurchak

    2013-11-01

    Full Text Available The article deals with studying indicators of lipid peroxidation (TBA-active products, lipid hydroperoxides, diene conjugates and antioxidant defense (superoxide dismutase, glutathione peroxidase, vitamins A and E in the blood of newborns on synchronized intermittent ventilation with pressure support and spontaneous breathing with continuous positive airway pressure via nasal cannula. The results show a more significant activation of lipid peroxidation system in newborns on synchronized intermittent ventilation with pressure support. The level of TBA-active products, lipid hydroperoxides, diene conjugates in their blood is 1.4 times higher, than the corresponding rates in children on continuous positive airway pressure via nasal cannula. In addition to activation of lipid peroxidation we observed a decrease of antioxidant protection in newborns on synchronized intermittent ventilation with pressure support. The level of superoxide dismutase in erythrocytes was 1.3 times lower, glutathione peroxidase in erythrocytes — 1,7 times lower, the serum level of vitamin A — 2.8 times lower and the serum vitamin E — 2.2 times lower comparing with newborns on continuous positive airway pressure via nasal cannula.

  8. Online Design Aid for Evaluating Manure Pit Ventilation Systems to Reduce Entry Risk

    Directory of Open Access Journals (Sweden)

    Harvey B. Manbeck

    2016-05-01

    Full Text Available On-farm manure storage pits contain both toxic and asphyxiating gases such as hydrogen sulfide, carbon dioxide, methane and ammonia. Farmers and service personnel occasionally need to enter these pits to conduct repair and maintenance tasks. One intervention to reduce the toxic and asphyxiating gas exposure risk to farm workers when entering manure pits is manure pit ventilation. This article describes an online computational fluid dynamics based design aid for evaluating the effectiveness of manure pit ventilation systems to reduce the concentrations of toxic and asphyxiating gases in the manure pits. This design aid, developed by a team of agricultural engineering and agricultural safety specialists at Pennsylvania State University, represents the culmination of more than a decade of research and technology development effort. The article includes a summary of the research efforts leading to the online design aid development and describes protocols for using the online design aid, including procedures for data input and for accessing design aid results. Design aid results include gas concentration decay and oxygen replenishment curves inside the manure pit and inside the barns above the manure pits, as well as animated motion pictures of individual gas concentration decay and oxygen replenishment in selected horizontal and vertical cut plots in the manure pits and barns. These results allow the user to assess: (1 how long one needs to ventilate the pits to remove toxic and asphyxiating gases from the pit and barn, (2 from which portions of the barn and pit these gases are most and least readily evacuated, and (3 whether or not animals and personnel need to be removed from portions of the barn above the manure pit being ventilated.

  9. Personalized ventilation.

    Science.gov (United States)

    Melikov, A K

    2004-01-01

    The thermal environment and air quality in buildings affects occupants' health, comfort and performance. The heating, ventilating and air-conditioning (HVAC) of buildings today is designed to provide a uniform room environment. However, large individual differences exist between occupants in regard to physiological and psychological response, clothing insulation, activity, air temperature and air movement preference, etc. Environmental conditions acceptable for most occupants in rooms may be achieved by providing each occupant with the possibility to generate and control his/her own preferred microenvironment. Furthermore, HVAC systems should be designed to protect occupants from airborne transmission of infectious agents that may be present in exhaled air. Personalized ventilation is a new development in the field of HVAC and has the potential to fulfill the above requirements. This paper reviews existing knowledge on performance of personalized ventilation (PV) and on human response to it. The airflow interaction in the vicinity of the human body is analyzed and its impact on thermal comfort and inhaled air quality is discussed together with control strategies and the application of PV in practice. Performance criteria are defined. Recommendations for design of PV that would be in compliance with the criteria are given. Future research needed on the topic is outlined. Personalized ventilation can improve occupants' comfort, decrease SBS symptoms and reduce the risk of transmission of contagion between occupants in comparison with total volume ventilation. However in order to perform efficiently in rooms in practice, the design (air distribution, control, etc.) has to be carefully considered together with type of occupant activity (occupancy rate, occupied density, etc.).

  10. Contribution to the study of hybrid ventilation system effectiveness in office and educational buildings; Contribution a l'etude de l'efficacite des systemes de ventilation hybride dans les batiments du secteur tertiaire

    Energy Technology Data Exchange (ETDEWEB)

    Cron, F.

    2004-06-15

    This study is part of the International Energy Agency Annex 35, 'Hybrid Ventilation in New and Retro-fitted Office Buildings', also called the HybVent Project. It presents the numerical analyses of a number of hybrid ventilation systems and their potential for several buildings in relation to local climate characteristics. The first part of this work reviews the state-of-the-art of existing ventilation systems and details the principles, expectations and features of hybrid ventilation systems. This first section also examines some examples of hybrid systems extracted from the collection of Annex 35 case studies. A comprehensive bibliography of numerical tools available for this type of analysis is given in the second section. The numerical models for building simulation and the object-oriented environment used to develop our simulation tool are presented in this section as well. Two single-zone studies undertaken in this project are reported in the third section. The first study concerns an experimental cell simulation. Numerical results are compared to experimental data to validate the use of the simulation tool developed. The second single-zone study predicts the potential of a specific hybrid ventilation system in a typical classroom, given climatic conditions. Finally, the last section presents a more complete study - a multi-zone study of the Tonga school, an Annex 35 case study located in Sweden. Three rooms were modelled initially to compare numerical results to experimental data and then to analyse the performance of the existing hybrid ventilation system and two other systems. This final study was completed for three European cities with very different climates. The overall analysis of the potential of the hybrid ventilation systems considered and the perspective for future work are outlined in the conclusion. (author)

  11. Stable and habitable systems with two giant planets

    Energy Technology Data Exchange (ETDEWEB)

    Dobos, Vera; Orgovanyi, Judit [Eoetvoes University, Pazmany Peter setany 1/A, 1117 Budapest (Hungary); Nagy, Imre, E-mail: vera.zs.dobos@gmail.co [Physical Geodesy and Geodesical Research Group of the HAS, Technical University, Muegyetem rakpart 3, 1111 Budapest (Hungary)

    2010-03-01

    We have studied planetary systems which are similar to the Solar System and built up from three inner rocky planets (Venus, Earth, Mars) and two outer gas giants. The stability of the orbits of the inner planets is discussed in the cases of different masses of the gas planets. To demonstrate the results stability maps were made and it was found that Jupiter could be four times and Saturn could be three times more massive while the orbits of the inner planets stay stable. Similar calculations were made by changing the mass of the Sun. In this case the position of the rocky planets and the extension of the liquid water habitable and the UV habitable zones were studied for different masses of the Sun. It was found that the orbits of the planets were stable for values greater than 0.33 M{sub s}un where M{sub s}un is the mass of the Sun and at lower masses of the Sun (at about 0.8 M{sub s}un) only Venus, but for higher mass values (at about 1.2 Msun) Earth and also Mars are located in both habitable zones.

  12. Multi-Zone hybrid model for failure detection of the stable ventilation systems

    DEFF Research Database (Denmark)

    Gholami, Mehdi; Schiøler, Henrik; Soltani, Mohsen

    2010-01-01

    In this paper, a conceptual multi-zone model for climate control of a live stock building is elaborated. The main challenge of this research is to estimate the parameters of a nonlinear hybrid model. A recursive estimation algorithm, the Extended Kalman Filter (EKF) is implemented for estimation...

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

    Science.gov (United States)

    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. Evaluation of a Mapleson D CPAP system for weaning of mechanical ventilation in pediatric patients.

    Science.gov (United States)

    Palomero-Rodríguez, Miguel Angel; de Arteaga, Héctor Chozas; Báez, Yolanda Laporta; de Vicente Sánchez, Jesús; Carretero, Pascual Sanabria; Conde, Pilar Sánchez; Pérez Ferrer, Antonio

    2016-01-01

    Over the last years, we have used a flow-inflating bag circuit with a nasotracheal or nasopharyngeal tube as an interface to deliver effective CPAP support in infants ("Mapleson D CPAP system"). The primary goal of this study was to assess the usefulness of the "Mapleson D CPAP system" for weaning of mechanical ventilation (MV) in infants who received MV over 24 h. All infants who received MV for more than 24 h in the last year were enrolled in the study. Demographic data included age, gender, weight, and admission diagnosis. Heart rate, respiratory rate, blood pressure, and oxygen saturation were measured during MV, 2 h after the nasotracheal Mapleson D CPAP system and 2 h after extubation. Patients were classified into two groups: patients MV more than 48 h, and patients with MV fewer than 48 h. P Mapleson D CPAP system and 2 h after extubation and spontaneous ventilation with the nasopharyngeal Mapleson D CPAP system or with nasal prongs. The overall extubation failure rate was 26% (n = 13). Weight and age were significantly associated with extubation failure (P Mapleson D CPAP system, in our opinion, is a useful and safe alternative to more complex and expensive noninvasive CPAP and BiPAP weaning from MV in infants.

  15. Evaluation of local exhaust ventilation system performance for control of Fe2O3 dust at an iron making unit

    Directory of Open Access Journals (Sweden)

    Mahdi Jamshidi Rastani

    2016-06-01

    Full Text Available Introduction: Adherence to the design values and ventilation standards (VS after installing and also maintaining continuous work of ventilation system with maximum performance throughout its life are amongst the reasons of ventilation systems monitoring. Therefore, the aim of this study was to evaluate performance of local exhaust ventilation system for control of dust by measuring the operating parameters and also to compare it with ventilation standards (VS and design values. Material and Method: The present research is a descriptive and cross-sectional study, conducted in three sections of measuring, monitoring and evaluating the operating parameters on hoods, channels and fan of ventilation system based on the current status of the system, documentation (design, and recommended standards (VS. Static pressure, velocity pressure, surface area, and flow rate were measured based on the recommendations of various sources and ACGIH industrial ventilation manual, and the data were compared with the design and recommended values, using the SPSS software version 16.   Result: The results of paired sample t-test between flow rate and velocities of design and current status, showed significant differences in various parts. Accordingly, the results revealed a reduction of more than 50% in the design duct velocity compared to the current duct velocity, while design duct velocity is 1.3 more than the standard duct velocity of current status, and current duct velocity is about 65% of standard duct velocity. Conclusion: The reduction and nonconformity of the results of measurements of operating parameters (after a minimum of two decades with design and standard values are corroborant and sufficient reason for obstructions, abrasions, leaks, imbalance of system ducts and their inefficiency in some branches. Since there is no base line measurements for system (supposing that the system worked with maximum amounts of setup time, one of the reasons for these

  16. Stable gastric pentadecapeptide BPC 157-NO-system relation.

    Science.gov (United States)

    Sikiric, Predrag; Seiwerth, Sven; Rucman, Rudolf; Turkovic, Branko; Rokotov, Dinko Stancic; Brcic, Luka; Sever, Marko; Klicek, Robert; Radic, Bozo; Drmic, Domagoj; Ilic, Spomenko; Kolenc, Danijela; Aralica, Gorana; Stupnisek, Mirjana; Suran, Jelena; Barisic, Ivan; Dzidic, Senka; Vrcic, Hrvoje; Sebecic, Bozidar

    2014-01-01

    We reviewed stable gastric pentadecapeptide BPC 157-NO-system-relation, its close participation in Moncada's (maintained vascular integrity, platelets control) homeostatic healing response of NO-system to injury. Namely, BPC 157's particular healing effect also affects all events after vascular integrity loss (dependent on circumstances, it reduces either thrombosis (abdominal aorta anastomosis) or bleeding/thrombocytopenia (amputation, heparin, warfarin, aspirin)) and in a series of different injurious models, acute and chronic, BPC 157 consistently advances healing after severe injuries in various tissues spontaneously unable to heal; stimulates egr-1 and naB2 genes; exhibits high safety (LD1 not achieved)). Hypothesis, that BPC 157 (since formed constitutively in the gastric mucosa, stable in human gastric juice, along with significance of NO-synthase and the basal formation of NO in stomach mucosa, greater than that seen in other tissues) exhibits a general, effective competing both with L-arginine analogues (i. e., L-NAME) and L-arginine, and that this has some physiologic importance (NO-generation), later, practically supports its beneficial effects illustrating BPC 157 and NOsystem mutual (with L-NAME/L-arginine; alone and together) relations in (i) gastric mucosa and mucosal protection, following alcohol lesions, in cytoprotection course, NO-generation, and blood pressure regulation; (ii) alcohol acute/chronic intoxication, and withdrawal; (iii) cardiovascular disturbances, chronic heart failure, pulmonary hypertension, and arrhythmias; (iv) disturbances after hypokalemia and hyperkalemia, and potassium-cell membrane dysfunction; and finally, in (v) complex healing failure, proved by the fistulas healing, colocutaneous and esophagocutaneous. However, how this advantage of modulating NO-system (i. e., particular effect on eNOS gene), may be practically translated into an enhanced clinical performance remains to be determined.

  17. Ultra-stable clock laser system development towards space applications.

    Science.gov (United States)

    Świerad, Dariusz; Häfner, Sebastian; Vogt, Stefan; Venon, Bertrand; Holleville, David; Bize, Sébastien; Kulosa, André; Bode, Sebastian; Singh, Yeshpal; Bongs, Kai; Rasel, Ernst Maria; Lodewyck, Jérôme; Le Targat, Rodolphe; Lisdat, Christian; Sterr, Uwe

    2016-09-26

    The increasing performance of optical lattice clocks has made them attractive for scientific applications in space and thus has pushed the development of their components including the interrogation lasers of the clock transitions towards being suitable for space, which amongst others requires making them more power efficient, radiation hardened, smaller, lighter as well as more mechanically stable. Here we present the development towards a space-compatible interrogation laser system for a strontium lattice clock constructed within the Space Optical Clock (SOC2) project where we have concentrated on mechanical rigidity and size. The laser reaches a fractional frequency instability of 7.9 × 10-16 at 300 ms averaging time. The laser system uses a single extended cavity diode laser that gives enough power for interrogating the atoms, frequency comparison by a frequency comb and diagnostics. It includes fibre link stabilisation to the atomic package and to the comb. The optics module containing the laser has dimensions 60 × 45 × 8 cm3; and the ultra-stable reference cavity used for frequency stabilisation with its vacuum system takes 30 × 30 × 30 cm3. The acceleration sensitivities in three orthogonal directions of the cavity are 3.6 × 10-10/g, 5.8 × 10-10/g and 3.1 × 10-10/g, where g ≈ 9.8 m/s2 is the standard gravitational acceleration.

  18. Stable Chlorine Isotope Study: Application to Early Solar System Materials

    Science.gov (United States)

    Mala,ira. M/; Nyquist, L. E.; Reese, Y.; Shih, C-Y; Fujitani, T.; Okano, O.

    2010-01-01

    A significantly large mass fractionation between two stable chlorine isotopes is expected during planetary processes In addition, in view of the isotopic heterogeneity of other light elements, the chlorine isotopes can potentially be used as a tracer for the origins and evolutionary processes of early solar system materials. Due to analytical difficulties, however, current chlorine isotope studies on planetary materials are quite controversial among IRMS (gas source mass spectrometry) and/or TIMS (Thermal Ionization Mass Spectrometry) groups [i.e. 1-3]. Although a cross-calibration of IRMS and TIMS indicates that both techniques are sufficiently consistent with each other [4], some authors have claimed that the Cl-37/Cl-35 ratio of geological samples obtained by TIMS technique are, in general, misleadingly too high and variable compared to those of IRMS [3]. For example, almost no differences of Cl isotope composition were observed among mantle materials and carbonaceous meteorites by [3]. On the other hand, according to more recent IRMS work [2], significant Cl isotope variations are confirmed for mantle materials. Therefore, additional careful investigation of Cl isotope analyses are now required to confirm real chlorine isotope variations for planetary materials including carbonaceous chondrites [5]. A significantly large mass fractionation between two stable chlorine isotopes is expected during planetary processes In addition, in view of the isotopic heterogeneity of other light elements, the chlorine isotopes can potentially be used as a tracer for the origins and evolutionary processes of early solar system materials. Due to analytical difficulties, however, current chlorine isotope studies on planetary materials are quite controversial among IRMS (gas source mass spectrometry) and/or TIMS (Thermal Ionization Mass Spectrometry) groups [i.e. 1-3]. Although a cross-calibration of IRMS and TIMS indicates that both techniques are sufficiently consistent with each

  19. Individually ventilated cages impose cold stress on laboratory mice: a source of systemic experimental variability.

    Science.gov (United States)

    David, John M; Knowles, Scott; Lamkin, Donald M; Stout, David B

    2013-11-01

    Individual ventilated cages (IVC) are increasing in popularity. Although mice avoid IVC in preference testing, they show no aversion when provided additional nesting material or the cage is not ventilated. Given the high ventilation rate in IVC, we developed 3 hypotheses: that mice housed in IVC experience more cold stress than do mice housed in static cages; that IVC-induced cold stress affects the results of experiments using mice; and that, when provided shelters, mice behaviorally thermoregulate and thereby rescue the cold-stress effects of IVC. To test these hypotheses, we housed mice in IVC, IVC with shelters, and static cages maintained at 20 to 21 °C. We quantified the cold stress of each housing system on mice by assessing nonshivering thermogenesis and brown adipose vacuolation. To test housing effects in a common, murine model of human disease, we implanted mice with subcutaneous epidermoid carcinoma cells and quantified tumor growth, tumor metabolism, and adrenal weight. Mice housed in IVC had histologic signs of cold stress and significantly higher nonshivering thermogenesis, smaller subcutaneous tumors, lower tumor metabolism, and larger adrenal weights than did mice in static cages. Shelters rescued IVC-induced nonshivering thermogenesis, adrenal enlargement, and phenotype-dependent cold-mediated histologic changes in brown adipose tissue and tumor size. IVC impose chronic cold stress on mice, alter experimental results, and are a source of systemic confounders throughout rodent-dependent research. Allowing mice to exhibit behavioral thermoregulation through seeking shelter markedly rescues the experiment-altering effects of housing-imposed cold stress, improves physiologic uniformity, and increases experimental reproducibility across housing systems.

  20. Applications and Energy Consumption of Demand Controlled Ventilation Systems. Modelling, Simulation and Implementation of Modular Built Dynamical VAV Systems and Control Strategies

    Energy Technology Data Exchange (ETDEWEB)

    Soerensen, Bjoern R.

    2002-07-01

    This thesis discusses many topics of heating and ventilation. This is because the ventilation system is an integrated part of its host building. The functionality and effectiveness of the ventilation system are very much dependent on the building's architectural design, its internal materials, its occupants, its air tightness characteristics and its placement in the terrain. Although this thesis emphasizes strongly on VAV (Variable Air Volume) systems and, in particular, modelling and simulation of such systems, it touches a range of important HVAC related issues. The scope is however, limited to the field of comfort ventilation. That is because ventilation in industrial environments often is subject to separate regulations, and requires other and specialized methods of design and evaluation of ventilation performance. The main objectives have been to: (1) Develop mathematical models for VAV components and systems. (2) Evaluate existing and develop new strategies for VAV demand controlled ventilation by system simulation. (3) Investigate the potential for saving energy and the impact on indoor climate. The development of mathematical models and simulation of VAV systems are given quite much attention compared to the other topics discussed.

  1. Heat pipes as perspective base elements of heat recovery in heat supply and ventilating systems

    Directory of Open Access Journals (Sweden)

    Matveev Andrey

    2017-01-01

    Full Text Available Thermotechnical characteristics of heat pipes are considered as high-efficient heat-transfer devices, which can provide energy-saving technologies for heat supply and ventilating systems and for different branches of industry. Thermotechnical and working (”performance capability” characteristics of heat pipes are investigated. By ”performance capability” of heat pipes and heat-transfer devices on heat pipes we mean the system state, where it can perform set functions and keep parameter values (thermal power, conductivity, thermal resistance, heat-transfer coefficient, temperature level and differential, etc. within the regulations of standardized specifications. The article presents theoretical and experimental methods of «gaslock» length determination on noncondensable gases during long-lasting tests of ammonia heat pipes made of aluminum shape АS – КRА 7.5 – R1 (alloy АD – 31. The paper gives results of research of thermotechnical characteristics of heat pipes in horizontal and vertical states (separate and as a set part while using different systems of thermal insulation. The obtained results of thermotechnical and resource tests show the advantages of ammonia heat pipes as basic elements for heat exchanger design in heating and ventilation systems.

  2. A method for evaluating the problem complex of choosing the ventilation system for a new building

    DEFF Research Database (Denmark)

    Hviid, Christian Anker; Svendsen, Svend

    2007-01-01

    for evaluating the performance of a ventilation system in the design proces by treating quantifiable and non-quantifiable datasets together. The method is based on general morphological analysis and applies cross-consistency assessment for reducing the problem complex, thus treating the multi......-dimensionality, the uncertainty and the subjectivity that arises in the design proces on a sound methodological and scientific basis. Through a distance analysis of the shared parameter values the solution scenarios may be plotted relative to each other, hence providing the designer with an illustrated ‘space of solutions...

  3. Stochastic systems driven by alpha-stable noises

    DEFF Research Database (Denmark)

    Ditlevsen, Ove Dalager; Ditlevsen, P.

    1998-01-01

    It has almost become a standard in stochastic mechanics applications of stochasticdifferential equations that the driving forces are modeled as Gaussian white noises, that is, as scalar or vector Brownianmotion increments.However, this modeling may not always lead to responses that comply well...... with observed data. In particular the tailsof the observed response distributions may even for linear systems be more fat than the tails obtained for Gaussianwhite noise input. Also the excitation may show jumps that cannot be modeled by Gaussian white noise. The paper supports the possibility of using...... the larger class of so-calledalpha-stable white noises to provide a better fit. A geophysical application concerning ice age climate variations is described....

  4. Establishment of transient and stable transfection systems for Babesia ovata.

    Science.gov (United States)

    Hakimi, Hassan; Yamagishi, Junya; Kegawa, Yuto; Kaneko, Osamu; Kawazu, Shin-Ichiro; Asada, Masahito

    2016-03-23

    Bovine babesiosis is a tick-borne disease caused by several species of Babesia which produce acute and fatal disease in cattle and affect livestock industry worldwide. Babesia ovata is a benign species widespread in east Asian countries and causes anemia, particularly in cattle which are co-infected with Theileria orientalis. The development of genetic manipulation methods is necessary to improve our understanding of the basic biology of protozoan pathogens toward a better control of disease. Such tools have not been developed for B. ovata, and are the aim of this study. In this study we transfected constructs that were designed to evaluate the ability of several B. ovata promoter candidates to drive expression of a reporter luciferase. We found that the elongation factor-1 alpha intergenic region (ef-1α IG) and the actin 5' non-coding region (NR) had highest promoter activities. To establish a stable transfection system, we generated a plasmid construct in which the ef-1α IG promoter drives gfp expression, and the actin 5' NR mediates expression of the selectable marker hdhfr. The plasmid was designed for episomal transfection, as well as to integrate by double cross-over homologous recombination into the ef-1α locus. Circular or linearized plasmid was transfected by electroporation into in vitro cultured B. ovata and retention of the plasmid was facilitated by drug selection with 5 nM WR99210 initiated 48 h after transfection. After one-week cultivation with WR99210, GFP-expressing parasites were observed by fluorescence microscopy. Integration of the plasmid construct into the ef-1α locus was confirmed by PCR, Southern blot analysis, and sequencing of recombination sites. These results confirm successful development of a stable transfection system for B. ovata. The current study provides a fundamental molecular tool to aid in molecular and cellular studies of B. ovata.

  5. Numerical analysis of diffuse ceiling ventilation and its integration with a radiant ceiling system

    DEFF Research Database (Denmark)

    Zhang, Chen; Heiselberg, Per Kvols; Chen, Qingyan

    2017-01-01

    A novel system combining diffuse ceiling ventilation and radiant ceiling was proposed recently, with the aim of providing energy efficient and comfort environment to office buildings. Designing of such a system is challenging because of complex interactions between the two subsystems and a large...... model was further applied to evaluate the effects of different design parameters, including the U-value of the diffuse ceiling panel, plenum height, plenum depth, and inlet configuration. In the integrated system, diffuse ceiling separated the radiant ceiling from the rest of the room and consequently...... changed the energy efficiency of the radiant system. The simulated results demonstrated that using ceiling panel with a higher U-value can minimize this impact and make the system to cool down space efficiently. Low plenum height was beneficial to the energy efficiency, but aggravated the non...

  6. A novel adaptive control system for noisy pressure-controlled ventilation: a numerical simulation and bench test study.

    Science.gov (United States)

    Beda, Alessandro; Spieth, Peter M; Handzsuj, Thomas; Pelosi, Paolo; Carvalho, Nadja C; Koch, Edmund; Koch, Thea; Gama de Abreu, Marcelo

    2010-01-01

    There is growing interest in the use of both variable and pressure-controlled ventilation (PCV). The combination of these approaches as "noisy PCV" requires adaptation of the mechanical ventilator to the respiratory system mechanics. Thus, we developed and evaluated a new control system based on the least-mean-squares adaptive approach, which automatically and continuously adjusts the driving pressure during PCV to achieve the desired variability pattern of tidal volume (V (T)). The controller was tested during numerical simulations and with a physical model reproducing the mechanical properties of the respiratory system. We applied step changes in respiratory system mechanics and mechanical ventilation settings. The time needed to converge to the desired V (T) variability pattern after each change (t (c)) and the difference in minute ventilation between the measured and target pattern of V (T) (DeltaMV) were determined. During numerical simulations, the control system for noisy PCV achieved the desired variable V (T) pattern in less than 30 respiratory cycles, with limited influence of the dynamic elastance (E*) on t (c), except when E* was underestimated by >25%. We also found that, during tests in the physical model, the control system converged in mechanical ventilation in the intensive care unit.

  7. Flow requirements and rebreathing during mechanically controlled ventilation in a T-piece (Mapleson E) system.

    Science.gov (United States)

    Hatch, D J; Yates, A P; Lindahl, S G

    1987-12-01

    The influence of fresh gas flow (FGF) setting on rebreathing was investigated in 15 infants and children (weight 3.5-21.8 kg) during balanced anaesthesia with mechanically controlled ventilation using a T-piece (Mapleson E) system and a Nuffield ventilator 200. Tidal volume (VT), minute volume (VE), maximal inspired (PICO2) and end-tidal (PE'CO2) carbon dioxide tensions and airway pressure were measured. VE, set to produce a PE'CO2 of about 4.5 kPa and measured at a high FGF (minimal rebreathing), was unchanged throughout the study and the regression equation for VE and weight was: VE (ml min-1) = 146 x kg + 482, r = 0.92. Measurements were then repeated at FGF:VE ratios reduced to 1.5 and 1.0. To achieve minimal rebreathing (PICO2 less than 0.5 kPa), FGF:VE ratios greater than 1.8 (range 1.8-4.9) had to be used. At FGF:VE ratios of 1.5, some alveolar rebreathing occurred, indicated by increased inspired (P less than 0.001) and end-tidal (P less than 0.001) carbon dioxide tensions. At FGF:VE ratios equal to 1.0, alveolar rebreathing was more pronounced and hypercapnoea occurred with a PE'CO2 (mean +/- 1 SD) of 5.89 +/- 0.53 kPa. At this FGF setting, change in I:E ratio from 1:2 to 1:1 did not influence the level of alveolar rebreathing. A minimal FGF (ml min-1) setting of 1.5 x VE (that is, 1.5 (146 x kg + 482), approximated to the expression (200 x kg + 1000) is recommended for controlled ventilation to avoid hypercapnoea when using the T-piece system in children weighing less than 20 kg.

  8. Displacement ventilation

    DEFF Research Database (Denmark)

    Kosonen, Risto; Melikov, Arsen Krikor; Mundt, Elisabeth

    The aim of this Guidebook is to give the state-of-the art knowledge of the displacement ventilation technology, and to simplify and improve the practical design procedure. The Guidebook discusses methods of total volume ventilation by mixing ventilation and displacement ventilation and it gives...... insights of the performance of the displacement ventilation. It also shows practical case studies in some typical applications and the latest research findings to create good local micro-climatic conditions....

  9. Problems with combined fresh air - off-air systems. Ventilation systems; Probleme bei kombinierten Zu- und Abluftgeraeten. Lueftungstechnische Anlagen

    Energy Technology Data Exchange (ETDEWEB)

    Lexis, J.

    2003-12-01

    As a rule, specifications on air volumes are made for ventilation systems for fresh air supply only or, alternatively, off-air removal only. In case of mixed air or recirculation, the required air volumes may differ considerably from the specifications. [German] In der Regel beziehen sich die Ausschreibungs- bzw. Garantieluftmengen auf den Betrieb einer lueftungstechnischen Anlage mit reiner Aussen- und Fortluft. Bei Umluft- oder Mischluftbetrieb koennen die geforderten Luftmengen jedoch erheblich von den Ausschreibungsforderungen abweichen. (orig.)

  10. Exploration Mission Particulate Matter Filtration Technology Performance Testing in a Simulated Spacecraft Cabin Ventilation System

    Science.gov (United States)

    Agui, Juan H.; Vijayakumar, R.; Perry, Jay L.; Frederick, Kenneth R.; Mccormick, Robert M.

    2017-01-01

    Human deep space exploration missions will require advances in long-life, low maintenance airborne particulate matter filtration technology. As one of the National Aeronautics and Space Administrations (NASA) developments in this area, a prototype of a new regenerable, multi-stage particulate matter filtration technology was tested in an International Space Station (ISS) module simulation facility. As previously reported, the key features of the filter system include inertial and media filtration with regeneration and in-place media replacement techniques. The testing facility can simulate aspects of the cabin environment aboard the ISS and contains flight-like cabin ventilation system components. The filtration technology test article was installed at the inlet of the central ventilation system duct and instrumented to provide performance data under nominal flow conditions. In-place regeneration operations were also evaluated. The real-time data included pressure drop across the filter stages, process air flow rate, ambient pressure, humidity and temperature. In addition, two video cameras positioned at the filtration technology test articles inlet and outlet were used to capture the mechanical performance of the filter media indexing operation under varying air flow rates. Recent test results are presented and future design recommendations are discussed.

  11. Natural Ventilation in Atria

    DEFF Research Database (Denmark)

    Svidt, Kjeld; Heiselberg, Per; Hendriksen, Ole Juhl

    This case study comprises a monitoring programme as well as a Computational Fluid Dynamics (CFD) analysis of a natural ventilated atrium. The purpose has been to analyse the performance of a typical natural ventilation system in Denmark under both summer and winter conditions.......This case study comprises a monitoring programme as well as a Computational Fluid Dynamics (CFD) analysis of a natural ventilated atrium. The purpose has been to analyse the performance of a typical natural ventilation system in Denmark under both summer and winter conditions....

  12. Analysis and Choice of Optimal Heating Ventilation Air Conditioning System for a Teaching Unit

    Directory of Open Access Journals (Sweden)

    Marina Verdeş

    2007-01-01

    Full Text Available Under the conditions of present society in which providing an optimum interior comfort is confronted with the necessity of the energy consumption reduction, solving this problem depends on the factors which contribute to the achievements of this comfort. Modern buildings -- implicitly teaching unit -- may be equipped with installations which have low energy consumption, respective a heating, cooling and ventilating integrated system with heat pumps system which can assure all the required comfort conditions. This paper underlines the necessity to use the heat pump in heating system for a teaching unit, energetic and economic guides and the possibility to increase them when using cooling and heating mixed. The solution of heat pumps for heating of the teaching unit and the energetic and economic advantages of the system is made in study.

  13. ASSESSMENT of POTENTIAL CARBON DIOXIDE-BASED DEMAND CONTROL VENTILATION SYSTEM PERFORMANCE in SINGLE ZONE SYSTEMS

    Science.gov (United States)

    2013-03-21

    8  Figure 3. Summer Philadelphia Office Space Indoor CO2 Concentration (Rackes and...Calculated Outdoor air Ventilation Rate (Jeong et al., 2010) .......................... 26  Figure 8. Calculated Zone CO2 Concentration (Jeong et al., 2010...29 Figure 11. Resulting CO2 Concentration in Different DCV Implementation

  14. The added value of hybrid ventilation/perfusion SPECT/CT in patients with stable COPD or apparently healthy smokers. Cancer-suspected CT findings in the lungs are common when hybrid imaging is used

    Directory of Open Access Journals (Sweden)

    Jögi J

    2014-12-01

    Full Text Available Jonas Jögi,1 Hanna Markstad,2 Ellen Tufvesson,3 Leif Bjermer,3 Marika Bajc1 1Department of Clinical Physiology and Nuclear Medicine, 2Department of Radiology, 3Department of Respiratory Medicine and Allergology, Skåne University Hospital and Lund University, Lund, Sweden Abstract: Ventilation/perfusion (V/P single-photon emission computed tomography (SPECT is recognized as a diagnostic method with potential beyond the diagnosis of pulmonary embolism. V/P SPECT identifies functional impairment in diseases such as heart failure (HF, pneumonia, and chronic obstructive pulmonary disease (COPD. The development of hybrid SPECT/computed tomography (CT systems, combining functional with morphological imaging through the addition of low-dose CT (LDCT, may be useful in COPD, as these patients are prone to lung cancer and other comorbidities. The aim of this study was to investigate the added value of LDCT among healthy smokers and patients with stable COPD, when examined with V/P SPECT/CT hybrid imaging. Sixty-nine subjects, 55 with COPD (GOLD I–IV and 14 apparently healthy smokers, were examined with V/P SPECT and LDCT hybrid imaging. Spirometry was used to verify COPD grade. Only one apparently healthy smoker and three COPD patients had a normal or nearly normal V/P SPECT. All other patients showed various degrees of airway obstruction, even when spirometry was normal. The same interpretation was reached on both modalities in 39% of the patients. LDCT made V/P SPECT interpretation more certain in 9% of the patients and, in 52%, LDCT provided additional diagnoses. LDCT better characterized the type of emphysema in 12 patients. In 19 cases, tumor-suspected changes were reported. Three of these 19 patients (ie, 4.3% of all subjects were in the end confirmed to have lung cancer. The majority of LDCT findings were not regarded as clinically significant. V/P SPECT identified perfusion patterns consistent with decompensated left ventricular HF in 14 COPD

  15. A computerized decision support system to predict the variations in the cerebral blood flow of mechanically ventilated infants.

    Science.gov (United States)

    Tehrani, Fleur T

    2013-10-01

    A computerized decision support system is described to predict the changes in the cerebral blood flow (CBF) of mechanically ventilated infants in response to different ventilatory settings. A CBF controller was developed and combined with a mathematical model of the infant's respiratory system to simulate the effects of ventilatory settings on the infant's CBF. The performance of the system was examined under various ventilatory treatments and the results were compared with available experimental data. The comparisons showed good agreement between the simulation results and experimental data for preterm infants. These included the results obtained under conditions of hypoventilation, hyperventilation, hypoxia, and hyperoxia. The presented decision support system has the potential to be used as an aide to the intensivist in choosing appropriate ventilation treatments for infants to prevent the untoward consequences of hazardous changes in CBF in mechanically ventilated infants such as hypoxic-ischemic brain injuries. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. Complications of mechanical ventilation

    Directory of Open Access Journals (Sweden)

    Drašković Biljana

    2011-01-01

    Full Text Available Mechanical ventilation of the lungs, as an important therapeutic measure, cannot be avoided in critically ill patients. However, when machines take over some of vital functions there is always a risk of complications and accidents. Complications associated with mechanical ventilation can be divided into: 1 airway-associated complications; 2 complications in the response of patients to mechanical ventilation; and 3 complications related to the patient’s response to the device for mechanical ventilation. Complications of artificial airway may be related to intubation and extubation or the endotracheal tube. Complications of mechanical ventilation, which arise because of the patient’s response to mechanical ventilation, may primarily cause significant side effects to the lungs. During the last two decades it was concluded that mechanical ventilation can worsen or cause acute lung injury. Mechanical ventilation may increase the alveolar/capillary permeability by overdistension of the lungs (volutrauma, it can exacerbate lung damage due to the recruitment/derecruitment of collapsed alveoli (atelectrauma and may cause subtle damages due to the activation of inflammatory processes (biotrauma. Complications caused by mechanical ventilation, beside those involving the lungs, can also have significant effects on other organs and organic systems, and can be a significant factor contributing to the increase of morbidity and mortality in critically ill of mechanically ventilated patients. Complications are fortunately rare and do not occur in every patient, but due to their seriousness and severity they require extensive knowledge, experience and responsibility by health-care workers.

  17. Double Shell Tank (DST) Ventilation System Vapor Sampling and Analysis Plan

    Energy Technology Data Exchange (ETDEWEB)

    SASAKI, L.M.

    2000-06-08

    This sampling and analysis plan (SAP) identifies characterization objectives pertaining to sample collection, laboratory analytical evaluation, and reporting requirements for vapor samples from the primary ventilation systems of the AN, AP, AW, and AY/AZ tank farms. Sampling will be performed in accordance with Data Quality Objectives for Regulatory Requirements for Hazardous and Radioactive Air Emissions Sampling and Analysis (Air DQO) (Mulkey 1999). The sampling will verify if current air emission estimates used in the permit application are correct and provide information for future air permit applications. Vapor samples will be obtained from tank farm ventilation systems, downstream from the tanks and upstream of any filtration. Samples taken in support of the DQO will consist of SUMMA{trademark} canisters, triple sorbent traps (TSTs), sorbent tube trains (STTs), polyurethane foam (PUF) samples. Particulate filter samples and tritium traps will be taken for radiation screening to allow the release of the samples for analysis. The following sections provide the general methodology and procedures to be used in the preparation, retrieval, transport, analysis, and reporting of results from the vapor samples.

  18. CFD Simulation and Optimisation of a Low Energy Ventilation and Cooling System

    Directory of Open Access Journals (Sweden)

    John Kaiser Calautit

    2015-04-01

    Full Text Available Mechanical Heating Ventilation and Air-Conditioning (HVAC systems account for 60% of the total energy consumption of buildings. As a sector, buildings contributes about 40% of the total global energy demand. By using passive technology coupled with natural ventilation from wind towers, significant amounts of energy can be saved, reducing the emissions of greenhouse gases. In this study, the development of Computational Fluid Dynamics (CFD analysis in aiding the development of wind towers was explored. Initial concepts of simple wind tower mechanics to detailed design of wind towers which integrate modifications specifically to improve the efficiency of wind towers were detailed. From this, using CFD analysis, heat transfer devices were integrated into a wind tower to provide cooling for incoming air, thus negating the reliance on mechanical HVAC systems. A commercial CFD code Fluent was used in this study to simulate the airflow inside the wind tower model with the heat transfer devices. Scaled wind tunnel testing was used to validate the computational model. The airflow supply velocity was measured and compared with the numerical results and good correlation was observed. Additionally, the spacing between the heat transfer devices was varied to optimise the performance. The technology presented here is subject to a patent application (PCT/GB2014/052263.

  19. Multifamily Ventilation Retrofit Strategies

    Energy Technology Data Exchange (ETDEWEB)

    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.

  20. Influence of paravertebral miorelaxant on arbitrary maximal ventilation of respirators system at skilled sportsmen

    Directory of Open Access Journals (Sweden)

    Syshko D.V.

    2012-09-01

    Full Text Available The functional being of the respirator system of the skilled sportsmen, engaged in the greco-roman fight (n=22, heavy athletics (n=25 and football (n=24 before and after course of paravertebral miorelaxant, is studied. The course of paravertebral miorelaxant was the system of exercises in a water environment with the use of «noodle». The necessity of application of correction influences, for sportsmen, was conditioned by the presence of hypertonic of paravertebral muscles, registered through miotonometric. It is got, those parameters of arbitrary maximal ventilation of respirators system (MVR, after the course of paravertebral miorelaxant, changed depending on the orientation of the training process determined by the type of sport. It is certain, whatever the change of tone of paravertebral muscles renders the reliable changes in the structure of arbitrary MVL at footballers, for certain affects chronotropics to the component at heavy athletics and inotropics at the representatives of the greco-roman fight.

  1. OPAL - extension for use with ventilation and pump systems; OPAL-Erweiterung mit Luefter- und Pumpensystemen

    Energy Technology Data Exchange (ETDEWEB)

    Tanner, R.

    2003-07-01

    This final report for the Swiss Federal Office of Energy (SFOE) discusses how an existing software tool called OPAL that supports the energy-efficient dimensioning of electrical drive systems was extended to cover pump and fan applications. According to the authors, the new version 3 allows the energy efficiency of such systems as well as the economic feasibility of many types of improvement projects to be evaluated in a fast and accurate manner. Software is described that has been designed and optimised using real world examples that can be often found in the water supply and facility management areas. These include heating-system pumps as well as ventilation and pressure-boosting applications. The practicability and benefits offered by the tool are demonstrated using several examples.

  2. Assessment of the Economic and Environmental Impact of Double Glazed Façade Ventilation Systems in Mediterranean Climates

    Directory of Open Access Journals (Sweden)

    Pere Alavedra

    2013-09-01

    Full Text Available Free convection is the most often used method in order to reduce solar load gains on a building with double glazed façades (DGFs. However, depending on the climate factors, the thermal performance of a DGF may not be satisfactory and extra energy costs are required to obtain suitable comfort conditions inside the building. Forced ventilation systems are a feasible alternative to improve the thermal performance of a DGF in Mediterranean climates where large solar gains are a permanent condition throughout the year. In this paper the feasibility of using diverse forced ventilation methods in DGF is evaluated. In addition, an economical comparison between different mechanical ventilation systems was performed in order to demonstrate the viability of DGF forced ventilation. Moreover, an environmental study was carried out to prove the positive energetic balance on cooling loads between free and forced convection in DGF for Mediterranean climates. For this investigation, a CFD model was used to simulate the thermal conditions in a DGF for the different ventilation systems. Results obtained for heat flux, temperature and reductions in solar load gains were analyzed and applied for the economic and environmental research.

  3. Experimental analysis of fuzzy controlled energy efficient demand controlled ventilation economizer cycle variable air volume air conditioning system

    Directory of Open Access Journals (Sweden)

    Rajagopalan Parameshwaran

    2008-01-01

    Full Text Available In the quest for energy conservative building design, there is now a great opportunity for a flexible and sophisticated air conditioning system capable of addressing better thermal comfort, indoor air quality, and energy efficiency, that are strongly desired. The variable refrigerant volume air conditioning system provides considerable energy savings, cost effectiveness and reduced space requirements. Applications of intelligent control like fuzzy logic controller, especially adapted to variable air volume air conditioning systems, have drawn more interest in recent years than classical control systems. An experimental analysis was performed to investigate the inherent operational characteristics of the combined variable refrigerant volume and variable air volume air conditioning systems under fixed ventilation, demand controlled ventilation, and combined demand controlled ventilation and economizer cycle techniques for two seasonal conditions. The test results of the variable refrigerant volume and variable air volume air conditioning system for each techniques are presented. The test results infer that the system controlled by fuzzy logic methodology and operated under the CO2 based mechanical ventilation scheme, effectively yields 37% and 56% per day of average energy-saving in summer and winter conditions, respectively. Based on the experimental results, the fuzzy based combined system can be considered to be an alternative energy efficient air conditioning scheme, having significant energy-saving potential compared to the conventional constant air volume air conditioning system.

  4. A study of energy use for ventilation and air-conditioning systems in Hong Kong

    Science.gov (United States)

    Yu, Chung Hoi Philip

    Most of the local modern buildings are high-rise with enclosed structure. Mechanical ventilation and air conditioning (MVAC) systems are installed for thermal comfort. Various types of MVAC systems found in Hong Kong were critically reviewed with comments on their characteristics in energy efficiency as well as application. The major design considerations were also discussed. Besides MVAC, other energy-consuming components in commercial buildings were also identified, such as lighting, lifts and escalators, office equipment, information technology facilities, etc. A practical approach has been adopted throughout this study in order that the end results will have pragmatic value to the heating, ventilating and air-conditioning (HVAC) industry in Hong Kong. Indoor Air Quality (IAQ) has become a major issue in commercial buildings worldwide including Hong Kong. Ventilation rate is no doubt a critical element in the design of HVAC systems, which can be realized more obviously in railway train compartments where the carbon dioxide level will be built up quickly when the compartments are crowded during rush hours. A study was carried out based on a simplified model using a train compartment that is equipped with an MVAC system. Overall Thermal Transfer Value (OTTV) is a single-value parameter for controlling building energy use and is relatively simple to implement legislatively. The local government has taken a first step in reacting to the worldwide concern of energy conservation and environmental protection since 1995. Different methods of OTTV calculation were studied and the computation results were compared. It gives a clear picture of the advantages and limitations for each method to the building designers. However, due to the limitations of using OTTV as the only parameter for building energy control, some new approaches to a total control of building energy use were discussed and they might be considered for future revision of the building energy codes in Hong

  5. NMR-based Stable Isotope Resolved Metabolomics in systems biochemistry.

    Science.gov (United States)

    Lane, Andrew N; Fan, Teresa W-M

    2017-08-15

    Metabolism is the basic activity of live cells, and monitoring the metabolic state provides a dynamic picture of the cells or tissues, and how they respond to external changes, for in disease or treatment with drugs. NMR is an extremely versatile analytical tool that can be applied to a wide range of biochemical problems. Despite its modest sensitivity its versatility make it an ideal tool for analyzing biochemical dynamics both in vitro and in vivo, especially when coupled with its isotope editing capabilities, from which isotope distributions can be readily determined. These are critical for any analyses of flux in live organisms. This review focuses on the utility of NMR spectroscopy in metabolomics, with an emphasis on NMR applications in stable isotope-enriched tracer research for elucidating biochemical pathways and networks with examples from nucleotide biochemistry. The knowledge gained from this area of research provides a ready link to genomic, epigenomic, transcriptomic, and proteomic information to achieve systems biochemical understanding of living cells and organisms. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. The role of ventilation and HVAC systems for human health in nonindustrial indoor environments. A supplementary review by EUROVEN group

    DEFF Research Database (Denmark)

    Wargocki, Pawel; Sundell, Jan; Bischof, W.

    2002-01-01

    with increased productivity, and that air-conditioning systems may increase the risk of sick building syndrome (SBS) symptoms. Taking these findings into account, the group has elaborated 35 hypotheses on the role of ventilation ahd HVAC systems in nonindustrial indoor environments with regard to human health...

  7. Dependence of flow variations on changes in aerodynamic resistances in underground mine ventilation systems with line-parallel branch connections

    Energy Technology Data Exchange (ETDEWEB)

    Vuletic, V.

    1980-01-01

    The parameters of ventilation systems which affect the interdependence of flow variations and changes of resistance in individual branches of the system are discussed. The investigation was carried out by simulation on an analogue computer. (11 refs.) (In Serbo-Croat)

  8. Experimental study including subjective evaluations of mixing and displacement ventilation combined with radiant floor heating/cooling system

    DEFF Research Database (Denmark)

    Krajcik, Michal; Tomasi, Roberta; Simone, Angela

    2013-01-01

    heating or by a combination of radiant floor heating and mixing ventilation system. The vertical air temperature distribution was more uniform for floor heating. The discomfort due to cold feet/lower legs was higher for warm air heating, but no significant difference in thermal perceptions between the two...... lower floor temperature, warmer supply air, and less homogeneous vertical temperature profile, but it did not result in thermal discomfort on feet/lower legs or discomfort due to a vertical air temperature difference higher than for a displacement ventilation system alone, where the floor temperature...

  9. Effect of a ceiling fan ventilation system on finishing young bulls' health, behaviour and growth performance.

    Science.gov (United States)

    Magrin, L; Brscic, M; Lora, I; Rumor, C; Tondello, L; Cozzi, G; Gottardo, F

    2017-06-01

    This research aimed at assessing the effects of a ceiling fan ventilation system on health, feeding, social behaviour and growth response of finishing young bulls fattened indoors during a mild summer season. A total of 69 Charolais young bulls were housed in six pens without any mechanical ventilation system (Control) and in six pens equipped with ceiling fans. The experimental period lasted 98 days from June until mid-September 2014. Four experimental days were considered in order to assess the effect of the ventilation system under two different microclimatic conditions: 2 alert days at monthly interval with temperature humidity index (THI) between 75 and 78, and 2 normal days with THI⩽74. Health and behaviour of the bulls were evaluated through 8-h observation sessions starting after morning feed delivery. The study was carried out during a rather cool summer with a climate average THI of 68.9 and 4 days with average THI>75. Despite these mild climate conditions, ceiling fans lowered litter moisture and acted as a preventive measure for bulls' dirtiness (odd ratio=47.9; 95% CI 19.6 to 117.4). The risk of abnormal breathing was increased for Control bulls (odd ratio=40.7; 95% CI 5.4 to 304.2). When exposed to alert THI conditions, respiration rate and panting scores increased and rumination duration dropped in Control bulls compared with bulls provided with a ceiling fan. During observations under alert THI, bulls spent less time eating, more time being inactive and consumed more water compared with normal THI conditions. Bulls' daily dry matter intake measured during the observation sessions decreased on alert compared with normal THI days (PCeiling fan treatment had no effect on bulls' growth performance or water consumption but these results most likely depended on the mild climate conditions. Ceiling fans proved to mitigate some of the negative effects of heat stress on bulls' behaviour (rumination, lying down and drinking water) and respiration rate

  10. Analysis of hybrid interface cooling system using air ventilation and nanofluid

    Science.gov (United States)

    Rani, M. F. H.; Razlan, Z. M.; Bakar, S. A.; Desa, H.; Wan, W. K.; Ibrahim, I.; Kamarrudin, N. S.; Bin-Abdun, Nazih A.

    2017-09-01

    The hybrid interface cooling system needs to be designed for maintaining the electric vehicle's battery cell temperature at 25°C. The hybrid interface cooling system is a combination of two individual systems, where the primary cooling system (R-134a) and the secondary cooling system (CuO + Water) will be used to absorb the heat generated by the battery cells. The ventilation system is designed using air as the medium to transfer the heat from the batteries to the refrigeration system (R-134a). Research will focus on determining the suitable compressor displacement, the heat exchanger volume and the expansion valve resistance value. The analysis for the secondary cooling system is focused on the cooling coil where low temperature nanofluid is passing through each interval of the battery cells. For analysing purposes, the thermal properties of the mixture of 50 grams, Copper (II) Oxide and the base fluid have been determined. The hybrid interface cooling system are able to achieve 57.82% increments in term of rate of heat transfer as compared to the individual refrigeration system.

  11. Evaluation of a Mapleson D CPAP system for weaning of mechanical ventilation in pediatric patients

    Directory of Open Access Journals (Sweden)

    Miguel Angel Palomero-Rodríguez

    2016-01-01

    Full Text Available Background: Over the last years, we have used a flow-inflating bag circuit with a nasotracheal or nasopharyngeal tube as an interface to deliver effective CPAP support in infants (“Mapleson D CPAP system”. The primary goal of this study was to assess the usefulness of the “Mapleson D CPAP system” for weaning of mechanical ventilation (MV in infants who received MV over 24 h. Materials and Methods: All infants who received MV for more than 24 h in the last year were enrolled in the study. Demographic data included age, gender, weight, and admission diagnosis. Heart rate, respiratory rate, blood pressure, and oxygen saturation were measured during MV, 2 h after the nasotracheal Mapleson D CPAP system and 2 h after extubation. Patients were classified into two groups: patients MV more than 48 h, and patients with MV fewer than 48 h. P < 0.05 was considered statistically significant. Results: A total of 50 children were enrolled in the study, with a median age was 34 ± 45 months (range, 1-59 months and median weight was 11.98 ± 9.31 kg (range, 1-48 kg. Median duration of MV was 480 h (range, 2-570. There were no significant differences in PaO 2 , PaCO 2 , and pH among MV, 2 h after the nasotracheal Mapleson D CPAP system and 2 h after extubation and spontaneous ventilation with the nasopharyngeal Mapleson D CPAP system or with nasal prongs. The overall extubation failure rate was 26% (n = 13. Weight and age were significantly associated with extubation failure (P < 0.05. Conclusions: The Mapleson D CPAP system, in our opinion, is a useful and safe alternative to more complex and expensive noninvasive CPAP and BiPAP weaning from MV in infants.

  12. Subjective Evaluation of the Microenvironment Generated by a Hospital Bed with Localized Ventilation System

    DEFF Research Database (Denmark)

    Kehayova, Nushka; Bolashikov, Zhecho Dimitrov; Melikov, Arsen Krikor

    2016-01-01

    A novel method for local hospital bed ventilation, called HBIVCU (Hospital Bed with Integrated Ventilation and Cleansing Unit), was studied in a human subject experiment. The goal of this study was to identify human response to the microenvironment generated by a hospital bed with installed HBIVCU...... and to compare with human response to the micro-environment at a hospital bed without local ventilation. 32 participants took part in two experimental conditions - hospital bed with and without installed HBIVCU. Subject’s votes on the bed microenvironment were collected via standardized questionnaires....... The subjects evaluated the perceived air quality in the ventilated bed as better compared to that in the non-ventilated bed. The whole body thermal sensation (WTS) and acceptability votes were decreasing over time for the non-ventilated bed condition. Significant differences in the local thermal sensation LTS...

  13. Evaluation of a Shaker Dust Collector for Use in a Recirculating Ventilation System.

    Science.gov (United States)

    Peters, Thomas M; Sawvel, Russell A; Park, Jae Hong; Anthony, T Renée

    2015-01-01

    General ventilation with recirculated air may be cost-effective to control the concentration of low-toxicity, contaminants in workplaces with diffuse, dusty operations, such as in agriculture. Such systems are, however, rarely adopted with little evidence showing improved air quality and ability to operate under harsh conditions. The goal of this work was to examine the initial and long-term performance of a fabric-filter shaker dust collector (SDC) in laboratory tests and as deployed within a recirculating ventilation system in an agricultural building. In laboratory tests, collection efficiency and pressure drop were tracked over several filter loading cycles, and the recovery of filter capacity (pressure drop) from filter shaking was examined. Collection efficiencies of particles larger than 5 μm was high (>95%) even when the filter was pristine, showing effective collection of large particles that dominate inhalable concentrations typical of agricultural dusts. For respirable-sized particles, collection efficiencies were low when the filter was pristine (e.g., 27% for 1 μm) but much higher when a dust cake developed on the filter (>99% for all size particles), even after shaking (e.g., 90% for 1 μm). The first shake of a filter was observed to recovery a substantial fraction of filter capacity, with subsequent shakes providing little benefit. In field tests, the SDC performed effectively over a period of three months in winter when incorporated in a recirculating ventilation system of a swine farrowing room. Trends in collection efficiency and pressure drop with loading were similar to those observed in the laboratory with overall collection efficiencies high (>80%) when pressure drop exceeded 230 Pa, or 23% of the maximum loading recommended by the manufacturer. This work shows that the SDC can function effectively over the harsh winter in swine rearing operations. Together with findings of improved air quality in the farrowing room reported in a

  14. Mechanical ventilation in children.

    Science.gov (United States)

    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.

  15. Control and prevention of ice formation and accretion on heat exchangers for ventilation systems

    DEFF Research Database (Denmark)

    Rahimi, Maral; Afshari, Alireza

    2015-01-01

    In cold climates, the application of mechanical ventilation systems with heat recovery like are airto-air exchangers is used for reducing energy consumption for heating buildings by transferring heat exhausted air to supply air. However, increase efficiency of heat exchanger results in lower...... exhaust air temperatures and Ice formation on heat exchanger fins, which can cause problem and is not favourable. Therefore, prevention and control of ice formation on heat exchangers is necessary. The existing methods are divided into two different methods: active and passive ice control methods....... The active methods are e.g. bypass, recirculation, preheating. The passive methods relate to the surface characteristics of the heat exchanger fins as they have effect on ice formation in initial phase. All these methods have varying levels of success, cost, and effectiveness, which are depending on the heat...

  16. Clinical experience and incidence of ventilator-associated pneumonia using closed versus open suction-system.

    Science.gov (United States)

    Åkerman, Eva; Larsson, Catharina; Ersson, Anders

    2014-01-01

    Studies have shown a decreasing ventilator-associated pneumonia (VAP) incidence after prophylactic interventions bundles. The use of closed suction systems (CSS) has been suggested beneficial as a prophylactic measure. To investigate the effects of a CSS on VAP incidence, suction circuit contamination and adverse events (AEs) compared to an open suction system (OSS) approach in a general mixed intensive care unit (ICU). Adult patients on mechanical ventilation were consecutively included. Data were collected during four 1-month periods where CSS and OSS were used on an alternating basis. Airway cultures were obtained at intubation, after 72 h and every Monday. After changing CSS and at extubation, the catheter tip was cultured. AEs and desaturation events during suction were monitored. Descriptive analysis and differences between the groups were analysed using comparative methods. No differences in airway colonization at admission between the groups were detected (Table 2). The CSS group had a higher Simplified Acute Physiology Score (SAPS) III and also a non-significant increase in VAP incidence. Positive cultures were obtained in 50% of all the retrieved CSS catheters. There was no inter-patient contamination in either group. Six AEs versus one (CSS/OSS) related to tube-occlusion and secretion clogging was seen. Desaturations at suctioning were rare in both groups. No beneficial effects were seen on VAP incidence or inter-patient contamination compared to OSS. A high frequency of circuit contamination in the CSS group paralleled with experienced secretions clearance problems seem unfavourable and in concordance with previous studies. © 2013 The Authors. Nursing in Critical Care © 2013 British Association of Critical Care Nurses.

  17. The Impact of an Extensive Usage of Controlled Natural Ventilation in the Residential Sector on Large-Scale Energy Systems

    DEFF Research Database (Denmark)

    Oropeza-Perez, Ivan

    energy in the world. Of this energy consumption, one of the highest energy-consuming activities within the buildings is concerning cooling. Technologies such as mechanical ventilation and air-conditioning are very used to achieve a certain thermal comfort within the building when there are periods...... simulation program and an energy systems analysis model are used as tools. The residential sectors of Denmark – temperate conditions – and Mexico – warm conditions – are used as case studies. In both scenarios, potential energy savings are assessed after using natural ventilation. Thereafter, environmental...

  18. Impact of ventilation systems and energy savings in a building on the mechanisms governing the indoor radon activity concentration.

    Science.gov (United States)

    Collignan, Bernard; Powaga, Emilie

    2017-11-23

    For a given radon potential in the ground and a given building, the parameters affecting the indoor radon activity concentration (IRnAC) are indoor depressurization of a building and its air change rate. These parameters depend mainly on the building characteristics, such as airtightness, and on the nature and performances of the ventilation system. This study involves a numerical sensitivity assessment of the indoor environmental conditions on the IRnAC in buildings. A numerical ventilation model has been adapted to take into account the effects of variations in the indoor environmental conditions (depressurization and air change rate) on the radon entry rate and on the IRnAC. In the context of the development of a policy to reduce energy consumption in a building, the results obtained showed that IRnAC could be strongly affected by variations in the air permeability of the building associated with the ventilation regime. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Mechanical ventilation of mice

    NARCIS (Netherlands)

    Schwarte, L. A.; Zuurbier, C. J.; Ince, C.

    2000-01-01

    Due to growing interest in murine functional genomics research, there is an increasing need for physiological stable in vivo murine models. Of special importance is support and control of ventilation by artificial respiration, which is difficult to execute as a consequence of the small size of the

  20. Researches Regarding the Efficiency of Water to Air Heat Exchanger with Heat Pipes for the Mechanical Ventilation System

    OpenAIRE

    Andrei Burlacu; Theodor Mateescu

    2007-01-01

    The present paper proposes the analysis of the efficiency of water to air heat exchanger with heat pipes for the mechanical ventilation system. The performed study is based on the necessity of the unconventional energy forms capitalization, increasing of the energy efficiency and the energy consumption decrease in concordance with the sustainable development concept.

  1. HOW THE LEED VENTILATION CREDIT IMPACTS ENERGY CONSUMPTION OF GSHP SYSTEMS A CASE STUDY FOR PRIMARY SCHOOLS

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xiaobing [ORNL

    2011-01-01

    This paper presents a study on the impacts of increased outdoor air (OA) ventilation on the performance of ground-source heat pump (GSHP) systems that heat and cool typical primary schools. Four locations Phoenix, Miami, Seattle, and Chicago are selected in this study to represent different climate zones in the United States. eQUEST, an integrated building and HVAC system energy analysis program, is used to simulate a typical primary school and the GSHP system at the four locations with minimum and 30% more than minimum OA ventilation. The simulation results show that, without an energy recovery ventilator, the 30% more OA ventilation results in an 8.0 13.3% increase in total GSHP system energy consumption at the four locations. The peak heating and cooling loads increase by 20.2 30% and 14.9 18.4%, respectively, at the four locations. The load imbalance of the ground heat exchanger is increased in hot climates but reduced in mild and cold climates.

  2. Removal of Particles from the Supply Air of Ventilation Systems Avoiding the Formation of Sensory Pollution Source

    DEFF Research Database (Denmark)

    Bekö, Gabriel

    2008-01-01

    an important role. Sensory pollutants emitted from used filters can have significant adverse impact on occupant performance. Therefore, removal of particles from the supply air of ventilation systems without the subsequent emission of pollutants into the airstream seems to be essential. Correct maintenance...

  3. Researches Regarding the Efficiency of Water to Air Heat Exchanger with Heat Pipes for the Mechanical Ventilation System

    Directory of Open Access Journals (Sweden)

    Andrei Burlacu

    2007-01-01

    Full Text Available The present paper proposes the analysis of the efficiency of water to air heat exchanger with heat pipes for the mechanical ventilation system. The performed study is based on the necessity of the unconventional energy forms capitalization, increasing of the energy efficiency and the energy consumption decrease in concordance with the sustainable development concept.

  4. Ontology for Life-Cycle Modeling of Heating, Ventilating, and Air Conditioning (HVAC) Systems: Experimental Applications Using Revit

    Science.gov (United States)

    2012-03-01

    Center, Construction Engineering Research Laboratory (ERDC-CERL) has developed a core life- cycle building information model ( BIM ) based on three...was to promote consistency and quality of content created for Building Information Models ( BIMs ) across various disciplines. The HVAC MVD was...MVD. 15. SUBJECT TERMS building information modeling ( BIM ), ontology, Army facilities, heating, ventilating, and air-conditioning (HVAC) systems

  5. JACoW Virtual control commissioning for a large critical ventilation system: The CMS cavern use case

    CERN Document Server

    Booth, William; Bradu, Benjamin; Sourisseau, Samuel

    2018-01-01

    The current cavern ventilation control system of the CMS experiment at CERN is based on components which are already obsolete: the SCADA system, or close to the end of life: the PLCs. The control system is going to be upgraded during the LHC Long Shutdown 2 (2019-2020) and will be based on the CERN industrial control standard: UNICOS employing WinCC OA as SCADA and Schneider PLCs. Due to the critical nature of the CMS ventilation installation and the short allowed downtime, the approach was to design an environment based on the virtual commissioning of the new control. This solution uses a first principles model of the ventilation system to simulate the real process. The model was developed with the modelling and simulation software EcosimPro. In addition, the current control application of the cavern ventilation will also be re-engineered as it is not completely satisfactory in some transients where many sequences are performed manually and some pressure fluctuations observed could potentially cause issues t...

  6. Experimental Investigation of Convective Heat Transfer during Night Cooling with Different Ventilation Systems and Surface Emissivities

    DEFF Research Database (Denmark)

    Le Dreau, Jerome; Heiselberg, Per; Jensen, Rasmus Lund

    2013-01-01

    Night-time ventilation is a promising approach to reduce the energy needed for cooling buildings without reducing thermal comfort. Nevertheless actual building simulation tools have showed their limits in predicting accurately the efficiency of night-time ventilation, mainly due to inappropriate ...

  7. Copper stable isotopes to trace copper behavior in wetland systems.

    Science.gov (United States)

    Babcsányi, Izabella; Imfeld, Gwenaël; Granet, Mathieu; Chabaux, François

    2014-05-20

    Wetlands are reactive zones of the landscape that can sequester metals released by industrial and agricultural activities. Copper (Cu) stable isotope ratios (δ(65)Cu) have recently been used as tracers of transport and transformation processes in polluted environments. Here, we used Cu stable isotopes to trace the behavior of Cu in a stormwater wetland receiving runoff from a vineyard catchment (Alsace, France). The Cu loads and stable isotope ratios were determined in the dissolved phase, suspended particulate matter (SPM), wetland sediments, and vegetation. The wetland retained >68% of the dissolved Cu and >92% of the SPM-bound Cu, which represented 84.4% of the total Cu in the runoff. The dissolved Cu became depleted in (65)Cu when passing through the wetland (Δ(65)Cuinlet-outlet from 0.03‰ to 0.77‰), which reflects Cu adsorption to aluminum minerals and organic matter. The δ(65)Cu values varied little in the wetland sediments (0.04 ± 0.10‰), which stored >96% of the total Cu mass within the wetland. During high-flow conditions, the Cu flowing out of the wetland became isotopically lighter, indicating the mobilization of reduced Cu(I) species from the sediments and Cu reduction within the sediments. Our results demonstrate that the Cu stable isotope ratios may help trace Cu behavior in redox-dynamic environments such as wetlands.

  8. Fiber Bragg Grating Measuring System for Simultaneous Monitoring of Temperature and Humidity in Mechanical Ventilation

    Directory of Open Access Journals (Sweden)

    Carlo Massaroni

    2017-04-01

    Full Text Available During mechanical ventilation, the humidification of the dry air delivered by the mechanical ventilator is recommended. Among several solutions, heated wire humidifiers (HWHs have gained large acceptance to be used in this field. The aim of this work is to fabricate a measuring system based on fiber Bragg grating (FBG for the simultaneous monitoring of gas relative humidity (RH and temperature, intended to be used for providing feedback to the HWHs’ control. This solution can be implemented using an array of two FBGs having a different center wavelength. Regarding RH monitoring, three sensors have been fabricated by coating an FBG with two different moisture-sensitive and biocompatible materials: the first two sensors were fabricated by coating the grating with a 3 mm × 3 mm layer of agar and agarose; to investigate the influence of the coating thickness to the sensor response, a third sensor was developed with a 5 mm × 5 mm layer of agar. The sensors have been assessed in a wide range of RH (up to 95% during both an ascending and a subsequent descending phase. Only the response of the 3 mm × 3 mm-coated sensors were fast enough to follow the RH changes, showing a mean sensitivity of about 0.14 nm/% (agar-coated and 0.12 nm/% (agarose-coated. The hysteresis error was about <10% in the two sensors. The contribution of temperature changes on these RH sensors was negligible. The temperature measurement was performed by a commercial FBG insensitive to RH changes. The small size of these FBG-based sensors, the use of biocompatible polymers, and the possibility to measure both temperature and RH by using the same fiber optic embedding an array of two FBGs make intriguing the use of this solution for application in the control of HWHs.

  9. Mild hypothermia attenuates changes in respiratory system mechanics and modifies cytokine concentration in bronchoalveolar lavage fluid during low lung volume ventilation.

    Science.gov (United States)

    Dostál, P; Senkeřík, M; Pařízková, R; Bareš, D; Zivný, P; Zivná, H; Cerný, V

    2010-01-01

    Hypothermia was shown to attenuate ventilator-induced lung injury due to large tidal volumes. It is unclear if the protective effect of hypothermia is maintained under less injurious mechanical ventilation in animals without previous lung injury. Tracheostomized rats were randomly allocated to non-ventilated group (group C) or ventilated groups of normothermia (group N) and mild hypothermia (group H). After two hours of mechanical ventilation with inspiratory fraction of oxygen 1.0, respiratory rate 60 min(-1), tidal volume 10 ml x kg(-1), positive end-expiratory pressure (PEEP) 2 cm H2O or immediately after tracheostomy in non-ventilated animals inspiratory pressures were recorded, rats were sacrificed, pressure-volume (PV) curve of respiratory system constructed, bronchoalveolar lavage (BAL) fluid and aortic blood samples obtained. Group N animals exhibited a higher rise in peak inspiratory pressures in comparison to group H animals. Shift of the PV curve to right, higher total protein and interleukin-6 levels in BAL fluid were observed in normothermia animals in comparison with hypothermia animals and non-ventilated controls. Tumor necrosis factor-alpha was lower in the hypothermia group in comparison with normothermia and non-ventilated groups. Mild hypothermia attenuated changes in respiratory system mechanics and modified cytokine concentration in bronchoalveolar lavage fluid during low lung volume ventilation in animals without previous lung injury.

  10. Development of an Integrated Residential Heating, Ventilation, Cooling, and Dehumidification System for Residences

    Energy Technology Data Exchange (ETDEWEB)

    Hoeschele, M.A.; D.A. Springer

    2008-06-18

    The Need and the Opportunity Codes such as ASHRAE 90.2 and IECC, and programs such as Energy Star and Builders Challenge, are causing new homes to be built to higher performance standards. As a result sensible cooling loads in new homes are going down, but indoor air quality prerogatives are causing ventilation rates and moisture loads to increase in humid climates. Conventional air conditioners are unable to provide the low sensible heat ratios that are needed to efficiently cool and dehumidify homes since dehumidification potential is strongly correlated with cooling system operating hours. The project team saw an opportunity to develop a system that is at least as effective as a conventional air conditioner plus dehumidifier, removes moisture without increasing the sensible load, reduces equipment cost by integrating components, and simplifies installation. Project Overview Prime contractor Davis Energy Group led a team in developing an Integrated Heating, Ventilation, Cooling, and Dehumidification (I-HVCD) system under the DOE SBIR program. Phase I and II SBIR project activities ran from July 2003 through December 2007. Tasks included: (1) Mechanical Design and Prototyping; (2) Controls Development; (3) Laboratory and Field Testing; and (4) Commercialization Activities Technology Description. Key components of the prototype I-HVCD system include an evaporator coil assembly, return and outdoor air damper, and controls. These are used in conjunction with conventional components that include a variable speed air handler or furnace, and a two-stage condensing unit. I-HVCD controls enable the system to operate in three distinct cooling modes to respond to indoor temperature and relative humidity (RH) levels. When sensible cooling loads are high, the system operates similar to a conventional system but varies supply airflow in response to indoor RH. In the second mode airflow is further reduced, and the reheat coil adds heat to the supply air. In the third mode, the

  11. Design Procedure for Hybrid Ventilation

    DEFF Research Database (Denmark)

    Heiselberg, Per; Tjelflaat, Per Olaf

    Mechanical and natural ventilation systems have developed separately during many years. The natural next step in this development is development of ventilation concepts that utilises and combines the best features from each system into a new type of ventilation system - Hybrid Ventilation....... Buildings with hybrid ventilation often include other sustainable technologies and an energy optimisation requires an integrated approach in the design of the building and its mechanical systems. Therefore, the hybrid ventilation design procedure differs from the design procedure for conventional HVAC....... The first ideas on a design procedure for hybrid ventilation is presented and the different types of design methods, that is needed in different phases of the design process, is discussed....

  12. Ventilation and Heart Rate Monitoring in Drivers using a Contactless Electrical Bioimpedance System

    Science.gov (United States)

    Macías, R.; García, M. A.; Ramos, J.; Bragós, R.; Fernández, M.

    2013-04-01

    Nowadays, the road safety is one of the most important priorities in the automotive industry. Many times, this safety is jeopardized because of driving under inappropriate states, e.g. drowsiness, drugs and/or alcohol. Therefore several systems for monitoring the behavior of subjects during driving are researched. In this paper, a device based on a contactless electrical bioimpedance system is shown. Using the four-wire technique, this system is capable of obtaining the heart rate and the ventilation of the driver through multiple textile electrodes. These textile electrodes are placed on the car seat and the steering wheel. Moreover, it is also reported several measurements done in a controlled environment, i.e. a test room where there are no artifacts due to the car vibrations or the road state. In the mentioned measurements, the system response can be observed depending on several parameters such as the placement of the electrodes or the number of clothing layers worn by the driver.

  13. [Assessment of the air quality improment of cleaning and disinfection on central air-conditioning ventilation system].

    Science.gov (United States)

    Liu, Hongliang; Zhang, Lei; Feng, Lihong; Wang, Fei; Xue, Zhiming

    2009-09-01

    To assess the effect of air quality of cleaning and disinfection on central air-conditioning ventilation systems. 102 air-conditioning ventilation systems in 46 public facilities were sampled and investigated based on Hygienic assessment criterion of cleaning and disinfection of public central air-conditioning systems. Median dust volume decreased from 41.8 g/m2 to 0.4 g/m2, and the percentage of pipes meeting the national standard for dust decreased from 17.3% (13/60) to 100% (62/62). In the dust, median aerobic bacterial count decreased from 14 cfu/cm2 to 1 cfu/cm2. Median aerobic fungus count decreased from 10 cfu/cm2 to 0 cfu/cm2. The percentage of pipes with bacterial and fungus counts meeting the national standard increased from 92.4% (171/185) and 82.2% (152/185) to 99.4% (165/166) and 100% (166/166), respectively. In the ventilation air, median aerobic bacterial count decreased from 756 cfu/m3 to 229 cfu/m3. Median aerobic fungus count decreased from 382 cfu/m3 to 120 cfu/m3. The percentage of pipes meeting the national standard for ventilation air increased from 33.3% (81/243) and 62.1% (151/243) to 79.8% (292/366) and 87.7% (242/276), respectively. But PM10 rose from 0.060 mg/m3 to 0.068 mg/m3, and the percentage of pipes meeting the national standard for PM10 increased from 74.2% (13/60) to 90.2% (46/51). The cleaning and disinfection of central air-conditioning ventilation systems could have a beneficial effect of air quality.

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

    Science.gov (United States)

    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 or = 0.98 and %error 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. The effects of individually ventilated cages on the respiratory systems of male and female Wistar rats from birth until adulthood.

    Science.gov (United States)

    Marchesi, Guilherme D'Aprile; Soto, Sônia de Fatima; Castro, Isac de; Rodrigues, Thiago Guimarães; Moriya, Henrique Takachi; Almeida, Francine Maria de; Pazetti, Rogerio; Heimann, Joel Claudio; Furukawa, Luzia Naôko Shinohara

    2017-03-01

    To evaluate the respiratory systems of male and female rats maintained in individually ventilated cages (IVCs) from birth until adulthood. Female Wistar rats were housed in individually ventilated cages or conventional cages (CCs) and mated with male Wistar rats. After birth and weaning, the male offspring were separated from the females and kept in cages of the same type until 12 weeks of age. The level of food consumption was lower in male offspring (IVC=171.7±9; CC=193.1±20) than in female offspring (IVC=100.6±7; CC=123.4±0.4), whereas the water intake was higher in female offspring (IVC=149.8±11; CC=99.2±0) than in male offspring (IVC=302.5±25; CC=249.7±22) at 11 weeks of age when housed in IVCs. The cage temperature was higher in individually ventilated cages than in conventional cages for both male (IVCs=25.9±0.5; CCs=22.95±0.3) and female (IVCs=26.2±0.3; CCs=23.1±0.3) offspring. The respiratory resistance (IVC=68.8±2.8; CC=50.6±3.0) and elastance (IVC=42.0±3.9; CC=32.4±2.0) at 300 µm/kg were higher in the female offspring housed in ventilated cages. The ciliary beat values were lower in both the male (IVCs=13.4±0.2; CC=15±0.4) and female (IVC=13.5±0.4; CC=15.9±0.6) offspring housed in individually ventilated cages than in those housed in conventional cages. The total cell (IVC=117.5±9.7; CC=285.0±22.8), neutrophil (IVC=13.1±4.8; CC=75.6±4.1) and macrophage (IVC=95.2±11.8; CC=170.0±18.8) counts in the bronchoalveolar lavage fluid were lower in the female offspring housed in individually ventilated cages than in those housed in conventional cages. The environmental conditions that exist in individually ventilated cages should be considered when interpreting the results of studies involving laboratory animals. In this study, we observed gender dimorphism in both the water consumption and respiratory mechanics of rats kept in ventilated cages.

  16. The effects of individually ventilated cages on the respiratory systems of male and female Wistar rats from birth until adulthood

    Directory of Open Access Journals (Sweden)

    Guilherme D’Aprile Marchesi

    Full Text Available OBJECTIVE: To evaluate the respiratory systems of male and female rats maintained in individually ventilated cages (IVCs from birth until adulthood. METHODS: Female Wistar rats were housed in individually ventilated cages or conventional cages (CCs and mated with male Wistar rats. After birth and weaning, the male offspring were separated from the females and kept in cages of the same type until 12 weeks of age. RESULTS: The level of food consumption was lower in male offspring (IVC=171.7±9; CC=193.1±20 than in female offspring (IVC=100.6±7; CC=123.4±0.4, whereas the water intake was higher in female offspring (IVC=149.8±11; CC=99.2±0 than in male offspring (IVC=302.5±25; CC=249.7±22 at 11 weeks of age when housed in IVCs. The cage temperature was higher in individually ventilated cages than in conventional cages for both male (IVCs=25.9±0.5; CCs=22.95±0.3 and female (IVCs=26.2±0.3; CCs=23.1±0.3 offspring. The respiratory resistance (IVC=68.8±2.8; CC=50.6±3.0 and elastance (IVC=42.0±3.9; CC=32.4±2.0 at 300 µm/kg were higher in the female offspring housed in ventilated cages. The ciliary beat values were lower in both the male (IVCs=13.4±0.2; CC=15±0.4 and female (IVC=13.5±0.4; CC=15.9±0.6 offspring housed in individually ventilated cages than in those housed in conventional cages. The total cell (IVC=117.5±9.7; CC=285.0±22.8, neutrophil (IVC=13.1±4.8; CC=75.6±4.1 and macrophage (IVC=95.2±11.8; CC=170.0±18.8 counts in the bronchoalveolar lavage fluid were lower in the female offspring housed in individually ventilated cages than in those housed in conventional cages. CONCLUSIONS: The environmental conditions that exist in individually ventilated cages should be considered when interpreting the results of studies involving laboratory animals. In this study, we observed gender dimorphism in both the water consumption and respiratory mechanics of rats kept in ventilated cages.

  17. A static pressure reset control system with a new type of flow damper for use in low pressure ventilation systems

    DEFF Research Database (Denmark)

    Terkildsen, Søren; Svendsen, Svend

    2012-01-01

    The control strategy for mechanical ventilation systems has significant impact on the performance of the system, in terms of energy consumption and correct air distribution. This paper presents a static pressure reset control system employing a new type of flow damper with lower pressure loss...... shows that the droplet shaped damper resulted in an airflow of 234 L/s at 30 Pa pressure loss, more than twice the airflow past a flat-plate damper at the same pressure loss (114 L/s). Also the droplet shaped damper could operate precisely down to 5 Pa pressure loss. The programmed control algorithm...... significant fan power saving compared to a fixed static pressure control. A maximum static pressure of 15 Pa is a reduction of more than 50% compared to flat-plate dampers that required at least 30 Pa to operate precisely; this is expected to yield fan energy savings in practice....

  18. Measurement of HVAC system performance and local ventilation using passive perfluorocarbon tracer technology

    Energy Technology Data Exchange (ETDEWEB)

    Dietz, R.N.; Goodrich, R.W.

    1995-06-01

    In April of 1993, two (2) perfluorocarbon tracer (PFT) ventilation/indoor air quality assessment tests were performed in the Gleeson Hall building of the SUNY Farmingdale campus. The building was being modified, in part, as a result of significant occupant complaints of perceived poor air quality. The four story building had a basement first floor with air supplied normally by an HVAC system labelled as AC1. During this study, AC1 was inoperational and the basement interior rooms (walls) were primarily gone; the other three floors were still being used for classes. It is possible that a sense of poor air quality may have been perceived by first-floor occupants because they were working in the basement, but this issue could not be addressed. The second floor had two (2) lecture halls--Rm 202 (handled by AC4) and Rm 204 (handled by AC5); the balance of the second floor interior rooms and corridors was split between two other air handling systems, AC2 for the west side of the building and AC3 for the east side. The remaining 3rd and 4th floors were also split about evenly between AC2 and AC3. The perimeter rooms, equipped with wall units having their own outside air (OA) source plus centralized return air (RA) bypasses, were not included in this testing which was restricted to the basement floor (1st floor) and the four operating air handling systems, AC2 to AC5, during Test 1 and only AC2 to AC5 during Test 2. Two types of tests were performed using the full suite of 5 PFT types available. The first test was designed to measure the infiltration, exfiltration, and air exchange between the 5 AC zones above and the second test used the 5th tracer, which had been in the basement, as a distributed source throughout the four other zones to act as a surrogate pollutant source. This report provides final conclusions of both tests and suggestions regarding its usefulness in similar building ventilation and indoor air quality assessments.

  19. Silver zeolite antimicrobial activity in aluminium heating, ventilation and air conditioning system ducts.

    Science.gov (United States)

    Rizzetto, R; Mansi, A; Panatto, D; Rizzitelli, E; Tinteri, C; Sasso, T; Gasparini, R; Crovari, P

    2008-03-01

    Air pollution in confined environments is a serious health problem, in that most people spend long periods indoors (in homes, offices, classrooms etc.). Some people (children, the elderly, heart disease patients, asthmatic or allergic subjects) are at greater risk because of their conditions of frailty. The growing use of air-conditioning systems in many public and private buildings aggravates this health risk, especially when these systems are not correctly installed or regularly serviced. The aim of our study was to verify the capacity of Ag+ ions to stop the growth of bacteria and moulds inside the ducts of Heating, Ventilation and Air Conditioning system ducts (HVAC) systems when these ducts were lined with active Ag+ ions zeolite-coated panels. A Y-shaped HVAC model with two branches was used; one branch was made of traditional galvanized iron, as was the whole system, while the other was lined with active Ag+ zeolite-coated polyurethane panels. During the test, samples of dust present inside both ducts were collected and seeded in liquid and solid media to detect bacteria and moulds. The presence of bacteria was also sought in the air emerging from the outlets of both ducts. Tests made on samples of particulate collected from the two different ducts revealed a lower total bacterial load in the samples collected from the Ag+ zeolite-coated duct than in the samples from the traditional Zn galvanized duct. In addition, the values of bacterial load found in the air emerging from the Ag+ ions zeolite-lined duct were 5 times lower than those found in the air from the traditional galvanized iron duct. The utilization of Ag+ zeolite-coated panels in air-conditioning systems could improve the quality of the emerging air in comparison with traditional installations in galvanized iron. This innovation could prove particularly advantageous in the event of accidents during the installation of air-conditioning systems or of contaminated aerosols coming from outside.

  20. Demand Controlled Ventilation and Classroom Ventilation

    Energy Technology Data Exchange (ETDEWEB)

    Fisk, William J. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Mendell, Mark J. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Davies, Molly [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Eliseeva, Ekaterina [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Faulkner, David [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Hong, Tienzen [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Sullivan, Douglas P. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    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.

  1. Demand controlled ventilation and classroom ventilation

    Energy Technology Data Exchange (ETDEWEB)

    Fisk, William J. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Mendell, Mark J. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Davies, Molly [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Eliseeva, Ekaterina [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Faulkner, David [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Hong, Tienzen [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Sullivan, Douglas P. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    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.

  2. Displacement Ventilation

    DEFF Research Database (Denmark)

    Nielsen, Peter Vilhelm

    Displacement ventilation is an interesting new type of air distribution principle which should be considered in connection with design of comfort ventilation in both smal1 and large spaces. Research activities on displacement ventilation are large all over the world and new knowledge of design...... methods appears continuously. This book gives an easy introduction to the basis of displacement ventilation and the chapters are written in the order which is used in a design procedure. The main text is extended by five appendices which show some of the new research activities taking place at Aalborg...

  3. High frequency mechanical ventilation affects respiratory system mechanics differently in C57BL/6J and BALB/c adult mice.

    Science.gov (United States)

    Hadden, Hélène

    2013-01-15

    We tested the hypothesis that high frequency ventilation affects respiratory system mechanical functions in C57BL/6J and BALB/c mice. We measured respiratory mechanics by the forced oscillation technique over 1h in anesthetized, intubated, ventilated BALB/c and C57BL/6J male mice. We did not detect any change in airway resistance, Rn, tissue damping, G, tissue elastance, H and hysteresivity, eta in BALB/c mice during 1h of ventilation at 150 or at 450 breaths/min; nor did we find a difference between BALB/c mice ventilated at 150 breaths/min compared with 450 breaths/min. Among C57BL/6J mice, except for H, all parameters remained unchanged over 1h of ventilation in mice ventilated at 150 breaths/min. However, after 10 and 30 min of ventilation at 450 breaths/min, Rn, and respiratory system compliance were lower, and eta was higher, than their starting value. We conclude that high frequency mechanical ventilation affects respiratory system mechanics differently in C57BL/6J and BALB/c adult mice. Copyright © 2012 Elsevier B.V. All rights reserved.

  4. Reducing Mortality from Terrorist Releases of Chemical and Biological Agents: I. Filtration for Ventilation Systems in Commercial Building

    Energy Technology Data Exchange (ETDEWEB)

    Thatcher, Tracy L.; Daisey, Joan M.

    1999-09-01

    There is growing concern about potential terrorist attacks involving releases of chemical and/or biological (CB) agents, such as sarin or anthrax, in and around buildings. For an external release, the CB agent can enter the building through the air intakes of a building's mechanical ventilation system and by infiltration through the building envelope. For an interior release in a single room, the mechanical ventilation system, which often recirculates some fraction of the air within a building, may distribute the released CB agent throughout the building. For both cases, installing building systems that remove chemical and biological agents may be the most effective way to protect building occupants. Filtration systems installed in the heating, ventilating and air-conditioning (HVAC) systems of buildings can significantly reduce exposures of building occupants in the event of a release, whether the release is outdoors or indoors. Reduced exposures can reduce the number of deaths from a terrorist attack. The purpose of this report is to provide information and examples of the design of filtration systems to help building engineers retrofit HVAC systems. The report also provides background information on the physical nature of CB agents and brief overviews of the basic principles of particle and vapor filtration.

  5. Experimental study on the dynamic performance of a novel system combining natural ventilation with diffuse ceiling inlet and TABS

    DEFF Research Database (Denmark)

    Yu, Tao; Heiselberg, Per Kvols; Lei, Bo

    2016-01-01

    Highlights • Dynamic experiments are performed to study energy performance of a new HVAC system. • Designed control strategies show good utilization of natural ventilation cooling. • TABS work well with the diffuse ceiling in the dynamic measurements. • No local thermal comfort problem is found...... even in the extreme winter case. • Designed control strategies can be used in the future application of this system....

  6. PCR testing of a ventilated caging system to detect murine fur mites.

    Science.gov (United States)

    Jensen, Eric S; Allen, Kenneth P; Henderson, Kenneth S; Szabo, Aniko; Thulin, Joseph D

    2013-01-01

    Rodents housed in microisolation caging are commonly monitored for infectious agents by the use of soiled bedding sentinels. This strategy relies on the successful transmission of rodent pathogens from the index rodents via soiled bedding to sentinel cages and the subsequent infection or colonization of sentinel rodents. When the prevalence of a pathogen is low or the target agent is not readily transmitted by soiled bedding, alternative testing methodologies should be used. Given the continued prevalence of institutions self-reporting murine fur mites and with the advent of a new sensitive and specific PCR assay for mites, we sought to determine whether the exhaust system of an individual ventilated caging (IVC) system could be used for monitoring the rack's rodent population for mites rather than relying on the responses of sentinels. We deployed single cages of mice (Mus musculus) that were known to be infested with either Radfordia affinis or Myobia musculi on a 70-cage rack, sampled the horizontal exhaust manifolds weekly, and used the new PCR assay to test these samples for mite DNA. We detected the presence of fur mites at a 94.1% probability of detection within 4 wk of placement. Therefore, we recommend swabbing and testing the shelf exhaust manifolds of IVC racks rather than relying on soiled-bedding sentinels as an indicator of the mite status of the rodents on that rack.

  7. Use of Disinfectants and Sanitizers in Heating, Ventilation, Air Conditioning, and Refrigeration Systems

    Science.gov (United States)

    This letter is to brings attention several concerns that the Agency has regarding the use of sanitizer and/or disinfectant products, and other types of antimicrobial products, to treat the surfaces of heating, ventilation

  8. Effectiveness of a personalized ventilation system in reducing personal exposure against directly released simulated cough droplets

    DEFF Research Database (Denmark)

    Pantelic, J.; Tham, K. W.; Licina, Dusan

    2015-01-01

    The inhalation intake fraction was used as an indicator to compare effects of desktop personalized ventilation and mixing ventilation on personal exposure to directly released simulated cough droplets. A cough machine was used to simulate cough release from the front, back, and side of a thermal...... manikin at distances between 1 and 4m. Cough droplet concentration was measured with an aerosol spectrometer in the breathing zone of a thermal manikin. Particle image velocimetry was used to characterize the velocity field in the breathing zone. Desktop personalized ventilation substantially reduced...... the inhalation intake fraction compared to mixing ventilation for all investigated distances and orientations of the cough release. The results point out that the orientation between the cough source and the breathing zone of the exposed occupant is an important factor that substantially influences exposure...

  9. Mathematical model and minimal measurement system for optimal control of heated humidifiers in neonatal ventilation.

    Science.gov (United States)

    Verta, Antonella; Schena, Emiliano; Silvestri, Sergio

    2010-06-01

    The control of thermo-hygrometric conditions of gas delivered in neonatal mechanical ventilation appears to be a particularly difficult task, mainly due to the vast number of parameters to be monitored and the control strategies of heated humidifiers to be adopted. In the present paper, we describe the heat and fluid exchange occurring in a heated humidifier in mathematical terms; we analyze the sensitivity of the relative humidity of outlet gas as a function of thermo-hygrometric and fluid-dynamic parameters of delivered gas; we propose a control strategy that will enable the stability of outlet gas thermo-hygrometric conditions. The mathematical model is represented by a hyper-surface containing the functional relations between the input variables, which must be measured, and the output variables, which have to remain constant. Model sensitivity analysis shows that heated humidifier efficacy and stability of outlet gas thermo-hygrometric conditions are principally influenced by four parameters: liquid surface temperature, gas flow rate, inlet gas temperature and inlet gas relative humidity. The theoretical model has been experimentally validated in typical working conditions of neonatal applications. The control strategy has been implemented by a minimal measurement system composed of three thermometers, a humidity sensor, and a flow rate sensor, and based on the theoretical model. Outlet relative humidity, contained in the range 90+/-4% and 94+/-4%, corresponding with temperature variations in the range 28+/-2 degrees C and 38+/-2 degrees C respectively, has been obtained in the whole flow rate range typical of neonatal ventilation from 1 to 10 L/min. We conclude that in order to obtain the stability of the thermo-hygrometric conditions of the delivered gas mixture: (a) a control strategy with a more complex measurement system must be implemented (i.e. providing more input variables); (b) and the gas may also need to be pre-warmed before entering the humidifying

  10. Diffuse Ceiling Ventilation

    DEFF Research Database (Denmark)

    Zhang, Chen; Heiselberg, Per; Nielsen, Peter V.

    2014-01-01

    As a novel air distribution system, diffuse ceiling ventilation combines the suspended acoustic ceiling with ventilation supply. Due to the low-impulse supply from the large ceiling area, the system does not generate draught when supplying cold air. However, heat sources play an important role on...... temperature as well as optimizing the radiant cooling potential by combining with thermal mass is conducted and gives a direction for further investigation....

  11. Demonstration of the Performance of an Air-Type Photovoltaic Thermal (PVT System Coupled with a Heat-Recovery Ventilator

    Directory of Open Access Journals (Sweden)

    Jin-Hee Kim

    2016-09-01

    Full Text Available A heat-recovery ventilator (HRV effectively conducts ventilation by recovering waste heat from indoors to outdoors during heating periods. However, dew condensation associated with the HRV system may arise due to the difference between the indoor temperature and the very low outdoor temperature in winter, and this can decrease the heat exchange efficiency. These problems can be solved by the pre-heating of the incoming air, but additional energy is required when pursuing such a strategy. On the other hand, an air-type photovoltaic thermal (PVT system produces electricity and thermal energy simultaneously using air as the heat transfer medium. Moreover, the heated air from the air-type PVT system can be connected to the HRV to pre-heat the supply air instead of taking in the cold outdoor air. Thus, the ventilation efficiency can be improved and the problems arising during the heating period can be resolved. Consequentially, the heating energy required in a building can be reduced, with additional electricity acquired as well. In this paper, the performance of an air-type PVT system coupled with an HRV is assessed. To do this, air-type PVT collectors operating at 1 kWp were installed in an experimental house and coupled to an HRV system. Thermal performance and heating energy required during the winter season were analyzed experimentally. Furthermore, the electrical performances of the air-type PVT system with and without ventilation at the back side of the PV during the summer season were analyzed.

  12. DETERMINATION OF THE ZONE ENDANGERED BY METHANE EXPLOSION IN GOAF WITH CAVING OF LONGWALLS VENTILATED ON „Y” SYSTEM

    Directory of Open Access Journals (Sweden)

    Jarosław BRODNY

    2016-10-01

    Full Text Available One of the most dangerous and most commonly present risks in hard coal mines is methane hazard. During exploitation by longwall system with caving, methane is emitted to mine heading from the mined coal and coal left in a pile. A large amount of methane also flows from neighboring seams through cracks and fissures formed in rock mass. In a case of accumulation of explosive methane concentration in goaf zone and with appropriate oxygen concentration and occur-rence of initials (e.g. spark or endogenous fire, it may come to the explosion of this gas. In the paper there are present-ed results of numerical analysis of mixture of air and methane streams flow through the real heading system of a mine, characterized by high methane hazard. The aim of the studies was to analyze the ventilation system of considered head-ing system and determination of braking zones in goaf zone, in which dangerous and explosive concertation of methane can occur with sufficient oxygen concentration equal to at least 12%. Determination of position of these zones is neces-sary for the selection of appropriate parameters of the ventilation system to ensure safety of the crew. Analysis of the scale of methane hazard allows to select such a ventilation system of exploitation and neighboring headings that ensures chemical composition of mining atmosphere required by regulation, and required efficiency of methane drainage. The obtained results clearly show that numerical methods, combined with the results of tests in real conditions can be suc-cessfully used for the analysis of variants of processes related to ventilation of underground mining, and also in the anal-ysis of emergency states.

  13. Design and Integrate Improved Systems for Nuclear Facility Ventilation and Exhaust Operations

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-04-15

    Objective: The objective of this R&D project would complete the development of three new systems and integrate them into a single experimental effort. However, each of the three systems has stand-alone applicability across the DOE complex. At US DOE nuclear facilities, indoor air is filtered and ventilated for human occupancy, and exhaust air to the outdoor environment must be regulated and monitored. At least three technical standards address these functions, and the Los Alamos National Laboratory would complete an experimental facility to answer at least three questions: (1) Can the drag coefficient of a new Los Alamos air mixer be reduced for better operation in nuclear facility exhaust stacks? (2) Is it possible to verify the accuracy of a new dilution method for HEPA filter test facilities? (3) Is there a performance-based air flow metric (volumetric flow or mass flow) for operating HEPA filters? In summary, the three new systems are: a mixer, a diluter and a performance-based metric, respectively. The results of this project would be applicable to at least four technical standards: ANSI N13.1 Sampling and Monitoring Releases of Airborne Radioactive Substances from the Stacks and Ducts of Nuclear Facilities; ASTM F1471 Standard Test Method for Air Cleaning Performance of a High-Efficiency Particulate Air Filter System, ASME N511: In-Service Testing of Nuclear Air Treatment, Heating, Ventilating, and Air-Conditioning Systems, and ASME AG-1: Code On Nuclear Air And Gas Treatment. All of the three proposed new systems must be combined into a single experimental device (i.e. to develop a new function of the Los Alamos aerosol wind tunnel). Technical Approach: The Radiation Protection RP-SVS group at Los Alamos has an aerosol wind tunnel that was originally (2006) designed to evaluate small air samplers (cf. US EPA 40 CFR 53.42). In 2009, the tunnel was modified for exhaust stack verifications per the ANSI N13.1 standard. In 2010, modifications were started on the

  14. Diffuse Ceiling Ventilation

    DEFF Research Database (Denmark)

    Zhang, Chen; Yu, Tao; Heiselberg, Per Kvols

    -cooling period and night cooling potential. The investment cost of this ventilation system is about 5-10% lower than the conventional ones, because the acoustic ceiling could be directly applied as air diffuser and the use of plenum to distribute air reduces the cost of ductwork. There is a growing interest...... in applying diffuse ceiling ventilation in offices and other commercial buildings because of the benefits from both thermal comfort and energy efficiency aspects. The design guide introduces the principle and key characteristics of room air distribution with diffuse ceiling ventilation and the design...

  15. Ventilative Cooling

    DEFF Research Database (Denmark)

    Heiselberg, Per Kvols; Kolokotroni, Maria

    -of-the-art of ventilative cooling potentials and limitations, its consideration in current energy performance regulations, available building components and control strategies and analysis methods and tools. In addition, the report provides twenty six examples of operational buildings using ventilative cooling ranging from...

  16. Ventilation Effectiveness

    DEFF Research Database (Denmark)

    Mundt, M.; Mathisen, H. M.; Moser, M.

    Improving the ventilation effectiveness allows the indoor air quality to be significantly enhanced without the need for higher air changes in the building, thereby avoiding the higher costs and energy consumption associated with increasing the ventilation rates. This Guidebook provides easy...

  17. Total System Performance Assessment- License Appication Design Selection (LADS) Phase 1 Analysis for Post-Closure Ventilation (Design Alternative 3)

    Energy Technology Data Exchange (ETDEWEB)

    N. Erb

    1999-06-21

    The objective of this report is to evaluate the effect of potential changes to the TSPA-VA base case design on long-term repository performance. The design changes that are evaluated in this report include two configurations for post-closure ventilation. bow tie and open loop (Design Alternative 3 or D3). The following paragraphs briefly describe the motivation for evaluating post-closure ventilation. The bow tie configuration for post closure ventilation has been identified as a design alternative to the TSPA-VA base case model (CRWMS M&O, 1998a) that may provide improved performance by reducing the temperature and relative humidity within the waste package drifts. The bow tie configuration for post-closure ventilation is a closed-loop design. In this design. cross drifts are placed in pairs with each drift angling up on opposite sides of the repository. From the side, the cross drifts and side drifts form the shape of a bow tie. Movement of air through the system is driven by convective heating from the waste packages in the cross drifts. The open loop configuration is also being considered for its potential to improve post-closure performance of the repository. As with the bow tie configuration, the open loop is designed to decrease temperature and relative humidity within the waste package drifts. For the open loop configuration, air is drawn into the drifts from outside the mountain. The configuration for the repository with open-loop ventilation is similar to the base case repository design with a few added shafts to increase air flow through the drifts. This report documents the modeling assumptions and calculations conducted to evaluate the long-term performance of Design Alternative 3. The performance measure for this evaluation is dose rate. Results are presented that compare the dose-rate time histories with the new design alternatives to that for the TSPA-VA base case calculation (CRWMS M&O, 1998a).

  18. Inverse Modeling of Respiratory System during Noninvasive Ventilation by Maximum Likelihood Estimation

    Directory of Open Access Journals (Sweden)

    Esra Saatci

    2010-01-01

    Full Text Available We propose a procedure to estimate the model parameters of presented nonlinear Resistance-Capacitance (RC and the widely used linear Resistance-Inductance-Capacitance (RIC models of the respiratory system by Maximum Likelihood Estimator (MLE. The measurement noise is assumed to be Generalized Gaussian Distributed (GGD, and the variance and the shape factor of the measurement noise are estimated by MLE and Kurtosis method, respectively. The performance of the MLE algorithm is also demonstrated by the Cramer-Rao Lower Bound (CRLB with artificially produced respiratory signals. Airway flow, mask pressure, and lung volume are measured from patients with Chronic Obstructive Pulmonary Disease (COPD under the noninvasive ventilation and from healthy subjects. Simulations show that respiratory signals from healthy subjects are better represented by the RIC model compared to the nonlinear RC model. On the other hand, the Patient group respiratory signals are fitted to the nonlinear RC model with lower measurement noise variance, better converged measurement noise shape factor, and model parameter tracks. Also, it is observed that for the Patient group the shape factor of the measurement noise converges to values between 1 and 2 whereas for the Control group shape factor values are estimated in the super-Gaussian area.

  19. Computational fluid dynamics simulation of an earth-air heat exchanger for ventilation system

    Science.gov (United States)

    Raczkowski, Andrzej; Suchorab, Zbigniew; Czechowska-Kosacka, Aneta

    2017-07-01

    Directive 2010/31/EU (EPBD Recast) obligates European Union members to improve energetic performance of the buildings. One of the crucial standards of energy-saving buildings are the passive houses, which are characterized by annual maximum space heating below 15 kWh/(m2.a) and the use of the specific primary energy for all domestic applications (also heating, hot water production and electricity) below 120 kWh/(m2.a). To achieve this standard there should be applied the solutions based on ground energy acquisition. One of them is the earth-air heat exchanger (EAHC) for ventilation systems. The article presents numerical simulations conducted by solving partial differential equations for three dimensional heat transfer. For the simulations it was applied Computational Fluid Dynamics (CFD) technique. The efficiency of EAHC was considered under different values of external temperature during the winter period (from -24 to -8 °C). Obtained results prove linear correlation with calculations of EAHC according to standards of the Polish National Energy Conservation Agency (NAPE). The slope of regression between outlet temperatures calculated with CFD model and NAPE standards, equals 0.59 which means, that according the CFD model, the efficiency of the exchanger is lower.

  20. Liquid Ventilation

    Directory of Open Access Journals (Sweden)

    Qutaiba A. Tawfic

    2011-01-01

    Full Text Available Mammals have lungs to breathe air and they have no gills to breath liquids. 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 theoretical 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. The potential for multiple clinical applications for liquid-assisted ventilation will be clarified and optimized in future. Keywords: Liquid ventilation; perfluorochemicals; perfluorocarbon; respiratory distress; surfactant.

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

    Science.gov (United States)

    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. Demand control on room level of the supply air temperature in an air heating and ventilation system

    DEFF Research Database (Denmark)

    Polak, Joanna; Afshari, Alireza; Bergsøe, Niels Christian

    2017-01-01

    The aim of this study was to investigate a new strategy for control of supply air temperature in an integrated air heating and ventilation system. The new strategy enables demand control of supply air temperature in individual rooms. The study is based on detailed dynamic simulations of a combined...... air heating and ventilation system in a high performance single family house using BSim simulation software. The provision of the desired thermal conditions in different rooms was examined. Results show that the new control strategy can facilitate maintaining of desired temperatures in various rooms....... Moreover, this control strategy enables controlled temperature differentiation between rooms within the house and therefore provides flexibility and better balance in heat delivery. Consequently, the thermal conditions in the building can be improved....

  3. Use of fuzzy logic to control a gasifier biomass ventilation system and maintenance of the temperature in the oxidation zone; Uso da logica fuzzy para controle do sistema de ventilacao de um gaseificador de biomassa e manutencao da temperatura da zona de oxidacao

    Energy Technology Data Exchange (ETDEWEB)

    Rezende, Oscar L.T.; Kulitz, Hans H. [Instituto Federal de Educacao, Ciencia e Tecnologia do Espirito Santo (IFES), Vitoria, ES (Brazil); Silva, Jadir N.; Galvarro, Svetlana F.S.; Machado, Cassio [Universidade Federal de Vicosa (UFV), MG (Brazil)], E-mail: oscar@ifes.edu.br

    2012-11-01

    This study aims at developing a fuzzy-based algorithm to control the frequency applied to the motor of a gasifier ventilation system in order to ensure adequate temperature in the oxidation zone and produce good quality gas. The input variables of the fuzzy controller were: error, which determines the difference between the desired temperature and the temperature at a given instant; and temperature variation, which will inform if it is increasing or decreasing at a given instant. The response variable was the operation frequency of the ventilation system motor. The rule base was built based on experimental data. The tests with the control algorithm allowed us to see that it is possible to control the oxidation zone temperature - producing gas in a stable way, which does not occur in gasification processes without ventilation system control. (author)

  4. [Biological contamination in office buildings related to ventilation/air conditioning system].

    Science.gov (United States)

    Bródka, Karolina; Sowiak, Małgorzata; Kozajda, Anna; Cyprowski, Marcin; Irena, Szadkowska-Stańczyk

    2012-01-01

    Indoor air is contaminated with microorganisms coming from both the atmospheric air and sources present in premises. The aim of this study was to analyze the concentrations of biological agents in office buildings, dependending on ventilation/air conditioning system and season. The study covered office buildings (different in the system of ventila-tion/air conditioning). Air samples for assessing the levels of inhalable dust, endotoxins and (1-->3)-beta-D-glucans, were taken at the selected stationary points of each building during summer and winter. The air was sampled for 6 h, using portable sets consisting of the GilAir 5 pump and the head filled with a filter of fiber glass. The samples for the presence of airborne bacteria and fungi were collected twice during the day using the impaction method. Average concentrations of inhalable dust, bacteria, fungi, endotoxins and (1-->3)-beta-D-glucans in office premises were 0.09 mg/m3, 6.00 x 10(2) cfu/m3, 4.59 x 10(1) cfu/m3, 0.42 ng/m3 and 3.91 ng/m3, respectively. Higher concentrations of the investigated agents were found in summer. In premises with air conditioning concentrations of airborne fungi, (1-->3)-beta-D-glucans and inhalable dust were significantly lower in winter. In summer the trend was reverse except for (1-->3)-beta-D-glucans. Concentrations of biological agents were affected by the season and the presence of air conditioning. Concentrations of inhalable dust, bacteria, fungi, endotoxins and (1-->3)-beta-D-glucans, observed inside the office buildings, were significantly higher in summer than in winter. The presence of the air conditioning system modified in various ways the levels of biological agents. Its influence was greater on the concentration of fungi and (1-->3)-beta-D-glucans than on that of bacteria and endotoxins.

  5. Investigation into the effect of closed-system suctioning on the frequency of pediatric ventilator-associated pneumonia in a developing country.

    Science.gov (United States)

    Morrow, Brenda M; Mowzer, Rukaiya; Pitcher, Richard; Argent, Andrew C

    2012-01-01

    To investigate the effect of closed-system vs. open endotracheal suctioning on the frequency of ventilator-associated pneumonia and outcome in a pediatric intensive care unit in a developing country. Prospective observational and nonrandomized controlled clinical study. A 20-bed pediatric intensive care unit in a tertiary pediatric hospital. Infants and children mechanically ventilated for >24 hrs. : Pediatric intensive care unit suctioning systems were alternated monthly. An 8-month interim analysis was planned with a priori efficacy and futility study termination boundaries set at p .52, respectively. Demographic, clinical, and laboratory data were prospectively recorded. Ventilator-associated pneumonia was diagnosed using the Clinical Pulmonary Infection Score, and the results were confirmed retrospectively using Centers for Disease Control criteria. A total of 250 patients (median [interquartile range] age of 3.8 [1.2-15.0] months) in 263 pediatric intensive care unit admissions were included. Fifty-nine admissions developed ventilator-associated pneumonia, with a calculated rate of 45.1 infections per 1000 ventilated days. There was no difference in characteristics or outcome between patients on closed-system suctioning (n = 83) and those on open endotracheal suctioning (n = 180). The frequencies of ventilator-associated pneumonia for patients on closed-system suctioning and open endotracheal suctioning were 20.5% and 23.3%, respectively (p = .6), reaching the a priori set limit of futility. Patients who developed ventilator-associated pneumonia spent a median (interquartile range) of 22 (13-37) and 11 (8-16) days in the hospital and pediatric intensive care unit, respectively, compared to 14.5 (10-24) and 6 (4-8) days for those without ventilator-associated pneumonia (p < .001). A 22% proportion of patients who developed ventilator-associated pneumonia died compared to 11.3% of those without ventilator-associated pneumonia (p = .03). Risk factors for

  6. Direct transition from a stable equilibrium to quasiperiodicity in non-smooth systems

    DEFF Research Database (Denmark)

    Zhusubaliyev, Z.T.; Mosekilde, Erik

    2008-01-01

    regions in phase space. When this happens, one can observe a number of different bifurcation scenarios. One scenario is the continuous transformation of the stable equilibrium into a stable period-1 cycle. Another is the transformation of the stable equilibrium into an unstable period-1 cycle with complex......The purpose of this Letter is to show how a border-collision bifurcation in a piecewise-smooth dynamical system can produce a direct transition from a stable equilibrium point to a two-dimensional invariant torus. Considering a system of nonautonomous differential equations describing the behavior...... of a power electronic DC/DC converter, we first determine the chart of dynamical modes and show that there is a region of parameter space in which the system has a single stable equilibrium point. Under variation of the parameters, this equilibrium may collide with a discontinuity boundary between two smooth...

  7. NMR-based stable isotope resolved metabolomics in systems biochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Teresa W-M. [University of Louisville, Department of Chemistry (United States); Lane, Andrew N., E-mail: anlane01@louisville.edu [University of Louisville, Center for Regulatory Environmental Analytical Metabolomics (United States)

    2011-04-15

    An important goal of metabolomics is to characterize the changes in metabolic networks in cells or various tissues of an organism in response to external perturbations or pathologies. The profiling of metabolites and their steady state concentrations does not directly provide information regarding the architecture and fluxes through metabolic networks. This requires tracer approaches. NMR is especially powerful as it can be used not only to identify and quantify metabolites in an unfractionated mixture such as biofluids or crude cell/tissue extracts, but also determine the positional isotopomer distributions of metabolites derived from a precursor enriched in stable isotopes such as {sup 13}C and {sup 15}N via metabolic transformations. In this article we demonstrate the application of a variety of 2-D NMR editing experiments to define the positional isotopomers of compounds present in polar and non-polar extracts of human lung cancer cells grown in either [U-{sup 13}C]-glucose or [U-{sup 13}C,{sup 15}N]-glutamine as source tracers. The information provided by such experiments enabled unambiguous reconstruction of metabolic pathways, which is the foundation for further metabolic flux modeling.

  8. A Bayesian decision-support system for diagnosing ventilator-associated pneumonia.

    Science.gov (United States)

    Schurink, Carolina A M; Visscher, Stefan; Lucas, Peter J F; van Leeuwen, Henk J; Buskens, Erik; Hoff, Reinier G; Hoepelman, Andy I M; Bonten, Marc J M

    2007-08-01

    To determine the diagnostic performance of a Bayesian Decision-Support System (BDSS) for ventilator-associated pneumonia (VAP). A previously developed BDSS, automatically obtaining patient data from patient information systems, provides likelihood predictions of VAP. In a prospectively studied cohort of 872 ICU patients, VAP was diagnosed by two infectious-disease specialists using a decision tree (reference diagnosis). After internal validation daily BDSS predictions were compared with the reference diagnosis. For data analysis two approaches were pursued: using BDSS predictions (a) for all 9422 patient days, and (b) only for the 238 days with presumed respiratory tract infections (RTI) according to the responsible physicians. 157 (66%) of 238 days with presumed RTI fulfilled criteria for VAP. In approach (a), median daily BDSS likelihood predictions for days with and without VAP were 77% [Interquartile range (IQR) = 56-91%] and 14% [IQR 5-42%, p BDSS cut-off point for VAP was 46%, and with this cut-off point positive predictive value (PPV) and negative predictive value (NPV) were 6.1 and 99.6%, respectively [AUC = 0.857 (95% CI 0.827-0.888)]. In approach (b), optimal cut-off for VAP was 78%, and with this cut-off point PPV and NPV were 86 and 66%, respectively [AUC = 0.846 (95% CI 0.794-0.899)]. As compared with the reference diagnosis, the BDSS had good test characteristics for diagnosing VAP, and might become a useful tool for assisting ICU physicians, both for routinely daily assessment and in patients clinically suspected of having VAP. Empirical validation of its performance is now warranted.

  9. DNA accumulation on ventilation system filters in university buildings in Singapore.

    Directory of Open Access Journals (Sweden)

    Irvan Luhung

    Full Text Available Biological particles deposit on air handling system filters as they process air. This study reports and interprets abundance and diversity information regarding biomass accumulation on ordinarily used filters acquired from several locations in a university environment.DNA-based analysis was applied both to quantify (via DNA fluorometry and qPCR and to characterize (via high-throughput sequencing the microbial material on filters, which mainly processed recirculated indoor air. Results were interpreted in relation to building occupancy and ventilation system operational parameters.Based on accumulated biomass, average DNA concentrations per AHU filter surface area across nine indoor locations after twelve weeks of filter use were in the respective ranges 1.1 to 41 ng per cm2 for total DNA, 0.02 to 3.3 ng per cm2 for bacterial DNA and 0.2 to 2.0 ng DNA per cm2 for fungal DNA. The most abundant genera detected on the AHU filter samples were Clostridium, Streptophyta, Bacillus, Acinetobacter and Ktedonobacter for bacteria and Aspergillus, Cladosporium, Nigrospora, Rigidoporus and Lentinus for fungi. Conditional indoor airborne DNA concentrations (median (range were estimated to be 13 (2.6-107 pg/m3 for total DNA, 0.4 (0.05-8.4 pg/m3 for bacterial DNA and 2.3 (1.0-5.1 pg/m3 for fungal DNA.Conditional airborne concentrations and the relative abundances of selected groups of genera correlate well with occupancy level. Bacterial DNA was found to be more responsive than fungal DNA to differences in occupancy level and indoor environmental conditions.

  10. COST EFFECTIVE VOC EMISSION CONTROL STARTEGIES FOR MILITARY, AEROSPACE,AND INDUSTRIAL PAINT SPRAY BOOTH OPERATIONS: COMBINING IMPROVED VENTILATION SYSTEMS WITH INNOVATIVE, LOW COST EMISSION CONTROL TECHNOLOGIES

    Science.gov (United States)

    The paper describes a full-scale demonstration program in which several paint booths were modified for recirculation ventilation; the booth exhaust streams are vented to an innovative volatile organic compound (VOC) emission control system having extremely low operating costs. ...

  11. Bed-integrated local exhaust ventilation system combined with local air cleaning for improved IAQ in hospital patient rooms

    DEFF Research Database (Denmark)

    Bivolarova, Mariya Petrova; Melikov, Arsen Krikor; Mizutani, Chiyomi

    2016-01-01

    micro-environment was exhausted. Two modes of operation were studied: 1) the exhausted polluted air was discharged out of the room and 2) the polluted air was cleaned by the ACF material installed inside the mattress and recirculated back into the room. Both modes of operation efficiently reduced......The performance of a ventilated mattress (VM) used as a bed-integrated local exhaust ventilation system combined with air cleaning fabric (acid-treated activated carbon fibre (ACF) fabric) was developed and studied. The separate and combined effect of the VM and the local air cleaning for reducing....... The patient's body was covered with either a cotton sheet or with the ACF material used as a blanket. Ammonia gas released from the patient's groins simulated the body generated bio-effluents. At the location of the groins the surface area of the VM was perforated through which the contaminated air of the bed...

  12. Lecture Notes on Mixing Ventilation

    DEFF Research Database (Denmark)

    Nielsen, Peter Vilhelm

    The main task of the ventilation system or the air-conditioning system is to supply· and remove air and airborne materials and to supply or remove heat from a room. The necessary level of fresh air will be supplied to· a room by a ventilation system, and heat from equipment or solar radiation can...

  13. Descriptions and diagrams of the primary and annulus ventilation systems of the double-shell tank farms as of January 1988

    Energy Technology Data Exchange (ETDEWEB)

    Blackman, A.E.; Waters, E.D.

    1994-12-28

    This document is a compilation of information describing the ventilation systems of the Double-Shell Tank farms (214-AN, -AP, -AW, -AW, -AY, -AZ, and -SY). A general description of the primary tank and annulus ventilation systems is given along with specific information on the high efficiency particulate air (HEPA) filters, condensers, preheaters, exhaust fans, and piping. This information is considered to be current as of January 1988. 38 refs, 20 figs, 30 tabs.

  14. Radiological and toxicological analyses of tank 241-AY-102 and tank 241-C-106 ventilation systems

    Energy Technology Data Exchange (ETDEWEB)

    Himes, D.A.

    1998-08-11

    The high heat content solids contained in Tank 241-C-106 are to be removed and transferred to Tank 241-AY-102 by sluicing operations, to be authorized under project W320. While sluicing operations are underway, the state of these tanks will be transformed from unagitated to agitated. This means that the partition fraction which describes the aerosol content of the head space will increase from IE-10 to IE-8 (see WHC-SD-WM-CN062, Rev. 2 for discussion of partition fractions). The head spare will become much more loaded with suspended material. Furthermore, the nature of this suspended material can change significantly: sluicing could bring up radioactive solids which normally would lay under many meters of liquid supernate. It is assumed that the headspace and filter aerosols in Tank 241-AY-102 are a 90/10 liquid/solid split. It is further assumed that the sluicing line, the headspace in Tank 241-C-106, and the filters on Tank 241-C-106 contain aerosols which are a 67/33 liquid/solid split. The bases of these assumptions are discussed in Section 3.0. These waste compositions (referred to as mitigated compositions) were used in Attachments 1 through 4 to calculate survey meter exposure rates per liter of inventory in the various system components. Three accident scenarios are evaluated: a high temperature event which melts or burns the HEPA filters and causes releases from other system components; an overpressure event which crushes and blows out the HEPA filters and causes releases from other system components; and an unfiltered release of tank headspace air. The initiating event for the high temperature release is a fire caused by a heater malfunction inside the exhaust dust or a fire outside the duct. The initiating event for the overpressure event could be a steam bump which over pressurizes the tank and leads to a blowout of the HEPA filters in the ventilation system. The catastrophic destruction of the HEPA filters would release a fraction of the accumulated

  15. Mechanical Ventilation

    Science.gov (United States)

    ... 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 ...

  16. Nifedipine gastrointestinal therapeutic system versus atenolol in stable angina pectoris

    NARCIS (Netherlands)

    deVries, RJM; vandenHeuvel, AFM; Lok, DJA; Claessens, RJJ; Bernink, PJLM; Pasteuning, WH; Kingma, JH; Dunselman, PHJM

    1996-01-01

    The gastrointestinal therapeutic system formulation of nifedipine enables a once-daily dosing resulting in predictable, relatively constant plasma concentrations. To evaluate the efficacy and safety of this formulation and to compare this with the beta-blocker atenolol, we conducted a double-blind,

  17. Ceiling-mounted personalized ventilation system integrated with a secondary air distribution system - a human response study in hot and humid climate

    DEFF Research Database (Denmark)

    Bin, Yang; Sekhar, S.C.; Melikov, Arsen Krikor

    2010-01-01

    The benefits of thermal comfort and indoor air quality with personalized ventilation (PV) systems have been demonstrated in recent studies. One of the barriers for wide spread acceptance by architects and HVAC designers has been attributed to challenges and constraints faced in the integration...

  18. Improving the energy and IAQ performance of ventilation systems in Dutch dwellings

    NARCIS (Netherlands)

    Holsteijn, R.C.A. van; Li, W.L.; Valk, H.J.J.; Kornaat, W.

    2016-01-01

    MONICAIR - MONItoring & Control of Air quality in Individual Rooms - is a pre-competitive field research project of a broad consortium of Dutch ventilation unit manufacturers and research institutes, supported by the Dutch government. The first aim of the project is to investigate and compare the

  19. Smart architecture for stable multipoint fiber Bragg grating sensor system

    Science.gov (United States)

    Yeh, Chien-Hung; Tsai, Ning; Zhuang, Yuan-Hong; Huang, Tzu-Jung; Chow, Chi-Wai; Chen, Jing-Heng; Liu, Wen-Fung

    2017-12-01

    In this work, we propose and investigate an intelligent fiber Bragg grating (FBG)-based sensor system in which the proposed stabilized and wavelength-tunable single-longitudinal-mode erbium-doped fiber laser can improve the sensing accuracy of wavelength-division-multiplexing multiple FBG sensors in a longer fiber transmission distance. Moreover, we also demonstrate the proposed sensor architecture to enhance the FBG capacity for sensing strain and temperature, simultaneously.

  20. Ventilation and air conditioning systems in maritime productions units; Panorama dos sistemas de VAC em unidades maritimas de producao

    Energy Technology Data Exchange (ETDEWEB)

    Guedes, Fernando Pedrosa; Sztajnbok, Ernani Luis [PETROBRAS, Rio de Janeiro, RJ (Brazil); Padua, Carlos Eduardo Dantas de; Passos, Alfredo Silveira [DUOVAC Engenharia Ltda. (Brazil)

    2004-07-01

    In an Offshore Stationary Production Unit (SPU), the adequate project of the Ventilation and Air Conditioning (VAC) System is not only a thermal comfort requirement but part of the essential safety services of the installation and complement for area classification requirements associated with electrical equipment. The VAC installations are sometimes the object of complaints by onboard team. Problems such as unsatisfactory system performance, high noise levels in the accommodation quarters, offices and other areas and the discomfort caused by unbalanced ventilation and air conditioning systems, are some of the most frequent complaints. Air Conditioning systems are classified as Direct and Indirect Expansion. Decentralized systems with Indirect Expansion has been adopted in PETROBRAS projects. This conception is not used in VAC Systems for platforms installed in North Sea, where the use of Centralized Systems with Direct Expansion are more common. The objective of this work is to compare the VAC conception projects, analyzing their advantages and disadvantages . The evaluation of VAC System in PETROBRAS project, and their steps in SPU development, is also scope of this paper. (author)

  1. Role of ventilation systems in the prevention of hospital infection; Innai kansen boshi ni okeru kanki system no yakuwari

    Energy Technology Data Exchange (ETDEWEB)

    Ayliffe, G.

    1996-05-05

    This paper investigates and considers the actual state of hospital infection. The 80% or more of surgical wound infection is self-infection, for which the factor is the microorganisms that exist in a surgical wound at the completion of an operation. Airborne infection is generally due to staphylococcus aureus. There rarely is a bacteria carrier, and the germ is dispersed from him in some instances. Staphylococcus epidermis sticks to prosthesis, propagates and causes wound infection in rare occasions. Clostridium perfringens and escherichia coli also sometimes cause self-infection from wound. An ordinary plenum ventilation system is less effective for the prevention of wound infection. A remarkable example for reduction in infection is the employment of an ultra clean air system in joint replacement operations, showing reduction in joint septicemic infection from 1.5 to 0.3%. A vertical air flow system may be effectively employed in an operation room for the purpose of improving the air stream. No interrelation exists between the total number of indoor bacteria and infection without staphylococcus aureus. A person infected by methicillin-resistant staphylococcus has to be isolated into a unit. 13 refs., 1 fig., 1 tab.

  2. Variable Ventilation Improved Respiratory System Mechanics and Ameliorated Pulmonary Damage in a Rat Model of Lung Ischemia-Reperfusion

    Directory of Open Access Journals (Sweden)

    Patricia R. M. Rocco

    2017-05-01

    Full Text Available Lung ischemia-reperfusion injury remains a major complication after lung transplantation. Variable ventilation (VV has been shown to improve respiratory function and reduce pulmonary histological damage compared to protective volume-controlled ventilation (VCV in different models of lung injury induced by endotoxin, surfactant depletion by saline lavage, and hydrochloric acid. However, no study has compared the biological impact of VV vs. VCV in lung ischemia-reperfusion injury, which has a complex pathophysiology different from that of other experimental models. Thirty-six animals were randomly assigned to one of two groups: (1 ischemia-reperfusion (IR, in which the left pulmonary hilum was completely occluded and released after 30 min; and (2 Sham, in which animals underwent the same surgical manipulation but without hilar clamping. Immediately after surgery, the left (IR-injured and right (contralateral lungs from 6 animals per group were removed, and served as non-ventilated group (NV for molecular biology analysis. IR and Sham groups were further randomized to one of two ventilation strategies: VCV (n = 6/group [tidal volume (VT = 6 mL/kg, positive end-expiratory pressure (PEEP = 2 cmH2O, fraction of inspired oxygen (FiO2 = 0.4]; or VV, which was applied on a breath-to-breath basis as a sequence of randomly generated VT values (n = 1200; mean VT = 6 mL/kg, with a 30% coefficient of variation. After 5 min of ventilation and at the end of a 2-h period (Final, respiratory system mechanics and arterial blood gases were measured. At Final, lungs were removed for histological and molecular biology analyses. Respiratory system elastance and alveolar collapse were lower in VCV than VV (mean ± SD, VCV 3.6 ± 1.3 cmH20/ml and 2.0 ± 0.8 cmH20/ml, p = 0.005; median [interquartile range], VCV 20.4% [7.9–33.1] and VV 5.4% [3.1–8.8], p = 0.04, respectively. In left lungs of IR animals, VCV increased the expression of interleukin-6 and intercellular

  3. Variable Ventilation Improved Respiratory System Mechanics and Ameliorated Pulmonary Damage in a Rat Model of Lung Ischemia-Reperfusion.

    Science.gov (United States)

    Soluri-Martins, André; Moraes, Lillian; Santos, Raquel S; Santos, Cintia L; Huhle, Robert; Capelozzi, Vera L; Pelosi, Paolo; Silva, Pedro L; de Abreu, Marcelo Gama; Rocco, Patricia R M

    2017-01-01

    Lung ischemia-reperfusion injury remains a major complication after lung transplantation. Variable ventilation (VV) has been shown to improve respiratory function and reduce pulmonary histological damage compared to protective volume-controlled ventilation (VCV) in different models of lung injury induced by endotoxin, surfactant depletion by saline lavage, and hydrochloric acid. However, no study has compared the biological impact of VV vs. VCV in lung ischemia-reperfusion injury, which has a complex pathophysiology different from that of other experimental models. Thirty-six animals were randomly assigned to one of two groups: (1) ischemia-reperfusion (IR), in which the left pulmonary hilum was completely occluded and released after 30 min; and (2) Sham, in which animals underwent the same surgical manipulation but without hilar clamping. Immediately after surgery, the left (IR-injured) and right (contralateral) lungs from 6 animals per group were removed, and served as non-ventilated group (NV) for molecular biology analysis. IR and Sham groups were further randomized to one of two ventilation strategies: VCV (n = 6/group) [tidal volume (VT) = 6 mL/kg, positive end-expiratory pressure (PEEP) = 2 cmH2O, fraction of inspired oxygen (FiO2) = 0.4]; or VV, which was applied on a breath-to-breath basis as a sequence of randomly generated VT values (n = 1200; mean VT = 6 mL/kg), with a 30% coefficient of variation. After 5 min of ventilation and at the end of a 2-h period (Final), respiratory system mechanics and arterial blood gases were measured. At Final, lungs were removed for histological and molecular biology analyses. Respiratory system elastance and alveolar collapse were lower in VCV than VV (mean ± SD, VCV 3.6 ± 1.3 cmH20/ml and 2.0 ± 0.8 cmH20/ml, p = 0.005; median [interquartile range], VCV 20.4% [7.9-33.1] and VV 5.4% [3.1-8.8], p = 0.04, respectively). In left lungs of IR animals, VCV increased the expression of interleukin-6 and intercellular adhesion

  4. "Fighting the system": Families caring for ventilator-dependent children and adults with complex health care needs at home

    Directory of Open Access Journals (Sweden)

    Nielsen Erik W

    2011-07-01

    Full Text Available Abstract Background An increasing number of individuals with complex health care needs now receive life-long and life-prolonging ventilatory support at home. Family members often take on the role of primary caregivers. The aim of this study was to explore the experiences of families giving advanced care to family members dependent on home mechanical ventilation. Methods Using qualitative research methods, a Grounded Theory influenced approach was used to explore the families' experiences. A total of 15 family members with 11 ventilator-dependent individuals (three children and eight adults were recruited for 10 in-depth interviews. Results The core category, "fighting the system," became the central theme as family members were asked to describe their experiences. In addition, we identified three subcategories, "lack of competence and continuity", "being indispensable" and "worth fighting for". This study revealed no major differences in the families' experiences that were dependent on whether the ventilator-dependent individual was a child or an adult. Conclusions These findings show that there is a large gap between family members' expectations and what the community health care services are able to provide, even when almost unlimited resources are available. A number of measures are needed to reduce the burden on these family members and to make hospital care at home possible. In the future, the gap between what the health care can potentially provide and what they can provide in real life will rapidly increase. New proposals to limit the extremely costly provision of home mechanical ventilation in Norway will trigger new ethical dilemmas that should be studied further.

  5. "Fighting the system": families caring for ventilator-dependent children and adults with complex health care needs at home.

    Science.gov (United States)

    Dybwik, Knut; Tollåli, Terje; Nielsen, Erik W; Brinchmann, Berit S

    2011-07-04

    An increasing number of individuals with complex health care needs now receive life-long and life-prolonging ventilatory support at home. Family members often take on the role of primary caregivers. The aim of this study was to explore the experiences of families giving advanced care to family members dependent on home mechanical ventilation. Using qualitative research methods, a Grounded Theory influenced approach was used to explore the families' experiences. A total of 15 family members with 11 ventilator-dependent individuals (three children and eight adults) were recruited for 10 in-depth interviews. The core category, "fighting the system," became the central theme as family members were asked to describe their experiences. In addition, we identified three subcategories, "lack of competence and continuity", "being indispensable" and "worth fighting for". This study revealed no major differences in the families' experiences that were dependent on whether the ventilator-dependent individual was a child or an adult. These findings show that there is a large gap between family members' expectations and what the community health care services are able to provide, even when almost unlimited resources are available. A number of measures are needed to reduce the burden on these family members and to make hospital care at home possible. In the future, the gap between what the health care can potentially provide and what they can provide in real life will rapidly increase. New proposals to limit the extremely costly provision of home mechanical ventilation in Norway will trigger new ethical dilemmas that should be studied further.

  6. CARMENES ultra-stable cooling system: very promising results

    Science.gov (United States)

    Mirabet, E.; Carvas, P.; Lizon, J.-L.; Becerril, S.; Rodríguez, E.; Abril, M.; Cárdenas, M. C.; Morales, R.; Pérez, D.; Sánchez Carrasco, M. A.; Amado, P. J.; Seifert, W.; Quirrenbach, A.; Caballero, J. A.; Ribas, I.; Reiners, A.; Dreizler, S.

    2014-07-01

    CARMENES is a high resolution spectrograph to detect planets through the variation of radial velocity, destined for the Calar Alto Observatory in Almeria, Spain. The optical bench has a working temperature of 140K with a 24 hours stability of ±0,1K; goal ±0,01K. It is enclosed with a radiation shield actively cooled with thermalized nitrogen gas that flows through strategically positioned heat exchangers to remove its radiative load. The cooling system has an external preparation unit (N2GPU), which provides the nitrogen gas through actively vaporizing liquid nitrogen with heating resistances and a three stage circuit flow, each one controlled by an independent PID. Since CARMENES is still in the construction phase, a dedicated test facility has been built in order to simulate the instrument and correctly establish the N2GPU parameters. Furthermore, the test facility allows a wide range of configurations set-ups, which enables a full characterization of the N2GPU and the cooling system. The N2GPU has been designed to offer a wide temperature range of thermally stabilized nitrogen gas flow, which apart from CARMENES could also be used to provide ultra-high thermal stability in other cryogenic instruments. The present paper shows the testing of the cooling performance, the hardware used and the very promising results obtained.

  7. Measured performance of filtration and ventilation systems for fine and ultrafine particles and ozone in an unoccupied modern California house

    Energy Technology Data Exchange (ETDEWEB)

    Singer, Brett C. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Delp, William W. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Black, Douglas R. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Walker, Iain S. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2016-12-01

    This study evaluated nine ventilation and filtration systems in an unoccupied 2006 house located 250m downwind of the I-80 freeway in Sacramento, California. Systems were evaluated for reducing indoor concentrations of outdoor particles in summer and fall/winter, ozone in summer, and particles from stir-fry cooking. Air exchange rate was measured continuously. Energy use was estimated for year-round operation in California. Exhaust ventilation without enhanced filtration produced indoor PM2.5 that was 70% lower than outdoors. Supply ventilation with MERV13 filtration provided slightly less protection whereas supply MERV16 filtration reduced PM2.55 by 97-98% relative to outdoors. Supply filtration systems used little energy but provided no benefits for indoor-generated particles. Systems with MERV13-16 filters in the recirculating heating and cooling unit (FAU) operating continuously or 20 min/h reduced PM2.5 by 93-98%. Across all systems, removal percentages were higher for ultrafine particles and lower for black carbon, relative to PM2.5. Indoor ozone was 3-4% of outdoors for all systems except an electronic air cleaner that produced ozone. Filtration via the FAU or portable filtration units lowered PM2.5 by 25-75% when operated over the hour following cooking. The energy for year-round operation of FAU filtration with an efficient blower motor was estimated at 600 kWh/year.

  8. Automatic protective ventilation using the ARDSNet protocol with the additional monitoring of electrical impedance tomography

    Science.gov (United States)

    2014-01-01

    Introduction Automatic ventilation for patients with respiratory failure aims at reducing mortality and can minimize the workload of clinical staff, offer standardized continuous care, and ultimately save the overall cost of therapy. We therefore developed a prototype for closed-loop ventilation using acute respiratory distress syndrome network (ARDSNet) protocol, called autoARDSNet. Methods A protocol-driven ventilation using goal-oriented structural programming was implemented and used for 4 hours in seven pigs with lavage-induced acute respiratory distress syndrome (ARDS). Oxygenation, plateau pressure and pH goals were controlled during the automatic ventilation therapy using autoARDSNet. Monitoring included standard respiratory, arterial blood gas analysis and electrical impedance tomography (EIT) images. After 2-hour automatic ventilation, a disconnection of the animal from the ventilator was carried out for 10 seconds, simulating a frequent clinical scenario for routine clinical care or intra-hospital transport. Results This pilot study of seven pigs showed stable and robust response for oxygenation, plateau pressure and pH value using the automated system. A 10-second disconnection at the patient-ventilator interface caused impaired oxygenation and severe acidosis. However, the automated protocol-driven ventilation was able to solve these problems. Additionally, regional ventilation was monitored by EIT for the evaluation of ventilation in real-time at bedside with one prominent case of pneumothorax. Conclusions We implemented an automatic ventilation therapy using ARDSNet protocol with seven pigs. All positive outcomes were obtained by the closed-loop ventilation therapy, which can offer a continuous standard protocol-driven algorithm to ARDS subjects. PMID:24957974

  9. Mechanical ventilation in neurosurgical patients

    OpenAIRE

    Keshav Goyal; Ranadhir Mitra; Shweta Kedia

    2013-01-01

    Mechanical ventilation significantly affects cerebral oxygenation and cerebral blood flow through changes in arterial carbon dioxide levels. Neurosurgical patients might require mechanical ventilation for correction and maintenance of changes in the pulmonary system that occur either due to neurosurgical pathology or following surgery during the acute phase. This review discusses the basics of mechanical ventilation relevant to the neurosurgeon in the day-to-day management of neurosurgical pa...

  10. Mechanical ventilation in neurosurgical patients

    Directory of Open Access Journals (Sweden)

    Keshav Goyal

    2013-01-01

    Full Text Available Mechanical ventilation significantly affects cerebral oxygenation and cerebral blood flow through changes in arterial carbon dioxide levels. Neurosurgical patients might require mechanical ventilation for correction and maintenance of changes in the pulmonary system that occur either due to neurosurgical pathology or following surgery during the acute phase. This review discusses the basics of mechanical ventilation relevant to the neurosurgeon in the day-to-day management of neurosurgical patient requiring artificial support of the respiration.

  11. Comparison of a Constant Air Volume (CAV) and a Demand Controlled Ventilation (DCV) System in a Residential Building

    DEFF Research Database (Denmark)

    Mortensen, Dorthe Kragsig; Nielsen, Toke Rammer; Topp, Claus

    2008-01-01

    hygroscopic properties on indoor climate and energy consumption was investigated for the two systems. Dynamic simulations of the studio apartment were carried out in the program WUFI+ with weather data from Copenhagen including outside temperature end relative humidity. For the non-hygroscopic case...... it was found that the energy consumption for heating and operating the ventilation system could be reduced by respectively 8.0% and 10.6 % in the case of DCV without negative impact on the indoor climate. Including the hygroscopic properties of the materials resulted in a reduction of the energy consumption...

  12. Ventilation distribution and small airway function in patients with systemic sclerosis

    Directory of Open Access Journals (Sweden)

    B.R.A. Silva

    2017-05-01

    Full Text Available Background: Despite the importance of traditional pulmonary function tests (PFTs in managing systemic sclerosis (SSc, many patients with pulmonary disease diagnosed by computed tomography (CT present with normal PFTs. Objective: To evaluate the efficacy of the nitrogen single-breath washout (N2SBW test in diagnosing SSc and to correlate N2SBW parameters with the PFT indexes used in the follow-up of these patients, clinical data, and CT findings. Methods: Cross-sectional study in which 52 consecutive SSc patients were subjected to spirometry, body plethysmography, analysis of the diffusing capacity for carbon monoxide (DLCO, analysis of respiratory muscle strength, N2SBW testing, and CT analysis. Results: Twenty-eight patients had a forced vital capacity (FVC that was 120% of the predicted value, while 15 patients had a closing volume/vital capacity (CV/VC that was >120% of the predicted value. A significant difference in Phase III slopeN2SBW was observed when the patients with predominant traction bronchiectasis and honeycombing were compared to the patients with other CT patterns (p < 0.0001. The Phase III slopeN2SBW was correlated with FVC (rs = −0.845, p < 0.0001 and DLCO (rs = −0.600, p < 0.0001, and the CV/VC was correlated with FVC (rs = −0.460, p = 0.0006 and residual volume/total lung capacity (rs = 0.328, p = 0.017. Conclusion: Ventilation heterogeneity is a frequent finding in SSc patients that is associated with restrictive damage, changes in pulmonary diffusion, and CT patterns. In addition, approximately one-third of the patients presented with findings that were compatible with small airway disease. Keywords: Systemic sclerosis, Respiratory function tests, Nitrogen single-breath washout test

  13. Continuous on-line measurements of respiratory system, lung and chest wall mechanics during mechanic ventilation.

    Science.gov (United States)

    Kárason, S; Søndergaard, S; Lundin, S; Stenqvist, O

    2001-08-01

    We present a concept of on-line, manoeuvre-free monitoring of respiratory mechanics during dynamic conditions, displaying calculated alveolar pressure/volume curves continuously and separating lung and chest wall mechanics. Prospective observational study. Intensive care unit of a university hospital. Ten ventilator-treated patients with acute lung injury. Different positive end-expiratory pressure (PEEP) and tidal volumes, low flow inflation. Previously validated methods were used to present a single-value dynostatic compliance for the whole breath and a dynostatic volume-dependent initial, middle and final compliance within the breath. A high individual variation of respiratory mechanics was observed. Reproducibility of repeated measurements was satisfactory (coefficients of variations for dynostatic volume-dependent compliance: mechanics during ongoing ventilator treatment.

  14. The School Advanced Ventilation Engineering Software (SAVES)

    Science.gov (United States)

    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.

  15. Mechanisms of natural ventilation in livestock buildings

    DEFF Research Database (Denmark)

    Rong, Li; Bjerg, Bjarne Schmidt; Batzanas, Thomas

    2016-01-01

    Studies on the mechanisms of natural ventilation in livestock buildings are reviewed and influences on discharge and pressure coefficients are discussed. Compared to studies conducted on buildings for human occupation and industrial buildings which focus on thermal comfort, ventilation systems...

  16. Ventilation with heat recovery

    DEFF Research Database (Denmark)

    Tommerup, Henrik M.; Svendsen, Svend

    2005-01-01

    This paper presents the experiences from the use of ventilation with heat recovery in several experimental single-family houses developed and built within the last four years to meet the new Danish energy requirements of 2005. Included are descriptions of the ventilation system components...... and the main functional demands as well as measurements of the thermal efficiency, electricity consumptions and building air tightness. The paper addresses the aspects of minimizing the heat loss from the duct system and the heat recovery unit (when placed in an unheated attic space) in order to obtain...

  17. Riccati equations for stable well-posed linear systems : The generic case

    NARCIS (Netherlands)

    Curtain, RF

    2003-01-01

    Under the generic assumption that zero is in the resolvent set of the generator, we show that the optimal control problem for a stable well-posed linear system is equivalent to a control problem for its reciprocal system which has bounded generating operators. Consequently, the operator X that

  18. Analytical system for stable carbon isotope measurements of low molecular weight (C2-C6) hydrocarbons

    NARCIS (Netherlands)

    Zuiderweg, A.T.; Holzinger, R.; Roeckmann, T.

    2011-01-01

    We present setup, testing and initial results from a new automated system for stable carbon isotope ratio measurements on C2 to C6 atmospheric hydrocarbons. The inlet system allows analysis of trace gases from air samples ranging from a few liters for urban samples and samples with high mixing

  19. Thermal plumes in ventilated rooms

    DEFF Research Database (Denmark)

    Kofoed, Peter; Nielsen, Peter V.

    1990-01-01

    The design of a displacement ventilation system involves determination of the flow rate in the thermal plumes. The flow rate in the plumes and the vertical temperature gradient influence each other, and they are influenced by many factors. This paper shows some descriptions of these effects. Free...... to be the only possible approach to obtain the volume flow in: thermal plumes in ventilated rooms....

  20. Mapping stable direct and retrograde orbits around the triple system of asteroids (45) Eugenia

    Science.gov (United States)

    Araujo, R. A. N.; Moraes, R. V.; Prado, A. F. B. A.; Winter, O. C.

    2017-12-01

    It is widely accepted that knowing the composition and the orbital evolution of asteroids might help us to understand the process of formation of the Solar system. It is also known that asteroids can represent a threat to our planet. Such an important role has made space missions to asteroids a very popular topic in current astrodynamics and astronomy studies. Taking into account the increasing interest in space missions to asteroids, especially to multiple systems, we present a study that aims to characterize the stable and unstable regions around the triple system of asteroids (45) Eugenia. The goal is to characterize the unstable and stable regions of this system and to make a comparison with the system 2001 SN263, which is the target of the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) mission. A new concept was used for mapping orbits, by considering the disturbance received by the spacecraft from all perturbing forces individually. This method has also been applied to (45) Eugenia. We present the stable and unstable regions for particles with relative inclination between 0° and 180°. We found that (45) Eugenia presents larger stable regions for both prograde and retrograde cases. This is mainly because the satellites of this system are small when compared to the primary body, and because they are not close to each other. We also present a comparison between these two triple systems, and we discuss how these results can guide us in the planning of future missions.

  1. Low-Flow Extracorporeal Carbon Dioxide Removal Using the Hemolung Respiratory Dialysis System(®) to Facilitate Lung-Protective Mechanical Ventilation in Acute Respiratory Distress Syndrome.

    Science.gov (United States)

    Akkanti, Bindu; Rajagopal, Keshava; Patel, Kirti P; Aravind, Sangeeta; Nunez-Centanu, Emmanuel; Hussain, Rahat; Shabari, Farshad Raissi; Hofstetter, Wayne L; Vaporciyan, Ara A; Banjac, Igor S; Kar, Biswajit; Gregoric, Igor D; Loyalka, Pranav

    2017-06-01

    Extracorporeal carbon dioxide removal (ECCO2R) permits reductions in alveolar ventilation requirements that the lungs would otherwise have to provide. This concept was applied to a case of hypercapnia refractory to high-level invasive mechanical ventilator support. We present a case of an 18-year-old man who developed post-pneumonectomy acute respiratory distress syndrome (ARDS) after resection of a mediastinal germ cell tumor involving the left lung hilum. Hypercapnia and hypoxemia persisted despite ventilator support even at traumatic levels. ECCO2R using a miniaturized system was instituted and provided effective carbon dioxide elimination. This facilitated establishment of lung-protective ventilator settings and lung function recovery. Extracorporeal lung support increasingly is being applied to treat ARDS. However, conventional extracorporeal membrane oxygenation (ECMO) generally involves using large cannulae capable of carrying high flow rates. A subset of patients with ARDS has mixed hypercapnia and hypoxemia despite high-level ventilator support. In the absence of profound hypoxemia, ECCO2R may be used to reduce ventilator support requirements to lung-protective levels, while avoiding risks associated with conventional ECMO.

  2. Thermal comfort and indoor air quality in rooms with integrated personalized ventilation and under-floor air distribution systems

    DEFF Research Database (Denmark)

    Li, Ruixin; Sekhar ., S. C.; Melikov, Arsen Krikor

    2011-01-01

    A comprehensive study comprising physical measurements and human subject experiments was conducted to explore the potential for improving occupants' thermal comfort and indoor air quality (IAQ) using a personalized ventilation (PV) system combined with an under-floor air distribution(UFAD) system....... The integrated PV-UFAD system, when operated at relatively high temperature of the air supplied from the UFAD system, provided comfortable cooling of the facial region, improved inhaled air quality, and decreased the risk of "cold feet," which is often reported in rooms with UFAD alone. This article explores...... with thermal sensation at the face region. The measured inhaled air quality indices (personalized exposure effectiveness and personalized exposure index) were improved by decreasing PV supply air temperature. The perceived inhaled air freshness increased with the decrease of the inhaled air temperature...

  3. Evaluation of a Mapleson D CPAP system for weaning of mechanical ventilation in pediatric patients

    OpenAIRE

    Miguel Angel Palomero-Rodríguez; Héctor Chozas de Arteaga; Yolanda Laporta Báez; Jesús de Vicente Sánchez; Pascual Sanabria Carretero; Pilar Sánchez Conde; Antonio Pérez Ferrer

    2016-01-01

    Background: Over the last years, we have used a flow-inflating bag circuit with a nasotracheal or nasopharyngeal tube as an interface to deliver effective CPAP support in infants (“Mapleson D CPAP system”). The primary goal of this study was to assess the usefulness of the “Mapleson D CPAP system” for weaning of mechanical ventilation (MV) in infants who received MV over 24 h. Materials and Methods: All infants who received MV for more than 24 h in the last year were enrolled in the study. De...

  4. Mine Ventilation System Variable Resistance Regulate Air Quantity Economy and Its Impacts on Artisanal Mine in Ivory Coast

    Directory of Open Access Journals (Sweden)

    Kouame Kouame Arthur Joseph

    2016-01-01

    Full Text Available The artisanal gold mining is one of the major illegal activities in Ivory Coast. Thousands of indigents and foreigners including men, women and children are involved in this dangerous activity. Contracting contagious diseases such as HIV/AIDS and multiple lung diseases are commonplace on the artisanal mining sites due to air pollution. For this reason, the differential analysis, research mine ventilation system by changing the working windage adjustment for air flow of the economy, identifies factors, obtained discriminant variable resistance air volume control economic quantitative criteria for underground actual situation of joint variable resistance method and economic variable resistance than the concept of the development of effective mine ventilation system to improve air quantity adjusting rheostat economical way. The findings of this study can help lead to better safety practices in mining in order to improve the health and safety of the miners who are involved in artisanal mining activities in Ivory Coast and other mining sites over the world.

  5. A Study on a Control Method with a Ventilation Requirement of a VAV System in Multi-Zone

    Directory of Open Access Journals (Sweden)

    Hyo-Jun Kim

    2017-11-01

    Full Text Available The objective of this study was to propose a control method with a ventilation requirement of variable air volume (VAV system in multi-zone. In order to control the VAV system inmulti-zone, it is essential to control the terminal unit installed in each zone. A VAV terminal unit with conventional control method using a fixed minimum air flow can cause indoor air quality (IAQ issues depending on the variation in the number of occupants. This research proposes a control method with a ventilation requirement of the VAV terminal unit and AHU inmulti-zone. The integrated control method with an air flow increase model in the VAV terminal unit, AHU, and outdoor air intake rate increase model in the AHU was based on the indoor CO2 concentration. The conventional and proposed control algorithms were compared through a TRNSYS simulation program. The proposed VAV terminal unit control method satisfies all the conditions of indoor temperature, IAQ, and stratification. An energy comparison with the conventional control method showed that the method satisfies not only the indoor thermal comfort, IAQ, and stratification issue, but also reduces the energy consumption.

  6. The Mechanical Impact of Aerodynamic Stall on Tunnel Ventilation Fans

    Directory of Open Access Journals (Sweden)

    A. G. Sheard

    2012-01-01

    Full Text Available This paper describes work aimed at establishing the ability of a tunnel ventilation fan to operate without risk of mechanical failure in the event of aerodynamic stall. The research establishes the aerodynamic characteristics of a typical tunnel ventilation fan when operated in both stable and stalled aerodynamic conditions, with and without an anti-stall stabilisation ring, with and without a “nonstalling” blade angle and at full, half, and one quarter design speed. It also measures the fan’s peak stress, thus facilitating an analysis of the implications of the experimental results for mechanical design methodology. The paper concludes by presenting three different strategies for tunnel ventilation fan selection in applications where the selected fan will most likely stall. The first strategy selects a fan with a low-blade angle that is nonstalling. The second strategy selects a fan with a high-pressure developing capability. The third strategy selects a fan with a fitted stabilisation ring. Tunnel ventilation system designers each have their favoured fan selection strategy. However, all three strategies can produce system designs within which a tunnel ventilation fan performs reliably in-service. The paper considers the advantages and disadvantages of each selection strategy and considered the strengths and weaknesses of each.

  7. CFD and Ventilation Research

    DEFF Research Database (Denmark)

    Li, Y.; Nielsen, Peter V.

    2011-01-01

    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 on-going 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...

  8. Newer nonconventional modes of mechanical ventilation

    OpenAIRE

    Preet Mohinder Singh; Anuradha Borle; Anjan Trikha

    2014-01-01

    The conventional modes of ventilation suffer many limitations. Although they are popularly used and are well-understood, often they fail to match the patient-based requirements. Over the years, many small modifications in ventilators have been incorporated to improve patient outcome. The ventilators of newer generation respond to patient′s demands by additional feedback systems. In this review, we discuss the popular newer modes of ventilation that have been accepted in to clinical practice. ...

  9. Measure Guideline: Ventilation Cooling

    Energy Technology Data Exchange (ETDEWEB)

    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.

  10. Ventilation for Free

    NARCIS (Netherlands)

    Scholten, R.D.; Ter Haar, J.

    2014-01-01

    This "designers' manual" is made during the TIDO-course AR0533 Innovation & Sustainability. The goal of this manual is to give a clear and simple overview of some of the possibilities for using natural ventilation in buildings. These systems are described through their formulas to give an idea of

  11. Stable and efficient systems for the twenty-first century | Duisenberg ...

    African Journals Online (AJOL)

    Stable and efficient systems for the twenty-first century. W Duisenberg. Abstract. No Abstract. Securities Market Journal Vol. 10 (2) 2005: pp. 30-33. Full Text: EMAIL FULL TEXT EMAIL FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT · http://dx.doi.org/10.4314/smj.v10i1.39046 · AJOL African Journals Online.

  12. Continental-Scale Stable Isotope Measurements at NEON to Address Ecological Processes Across Systems

    Science.gov (United States)

    Luo, H.; Goodman, K. J.; Hinckley, E. S.; West, J. B.; Williams, D. G.; Bowen, G. J.

    2013-12-01

    The National Ecological Observatory Network (NEON) is a national-scale research platform. The overarching goal of NEON is to enable understanding and forecasting of the impacts of climate change, land use change, and invasive species on aspects of continental-scale ecology (such as biodiversity, biogeochemistry, infectious diseases, ecohydrology, etc.). NEON focuses explicitly on questions that relate to grand challenges in environmental science, are relevant to large regions, and would otherwise be very difficult to address with traditional ecological approaches. The use of stable isotope approaches in ecological research has grown steadily during the last two decades. Stable isotopes at natural abundances in the environment trace and integrate the interaction between abiotic and biotic components across temporal and spatial scales. In this poster, we will present the NEON data products that incorporate stable isotope measurements in atmospheric, terrestrial, and aquatic ecosystems in North America. We further outline current questions in the natural sciences community and how these data products can be used to address continental-scale ecological questions, such as the ecological impacts of climate change, terrestrial-aquatic system linkages, land-atmosphere exchange, landscape ecohydrological processes, and linking biogeochemical cycles across systems. Specifically, we focus on the use of stable isotopes to evaluate water availability and residence times in terrestrial systems, as well as nutrient sources to terrestrial systems, and cycling across ecosystem boundaries.

  13. Development of a microprocessor-controlled coulometric system for stable ph control

    NARCIS (Netherlands)

    Bergveld, Piet; van der Schoot, B.H.

    1983-01-01

    The coulometric pH control system utilizes a programmable coulostat for controlling the pH of a certain volume of unbuffered solution. Based on theoretical considerations, conditions are established which guarantee stable operation with maximum suppression of disturbances from the dissolution of

  14. Understanding mechanical ventilators.

    Science.gov (United States)

    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.

  15. Thermal comfort and IAQ assessment of under-floor air distribution system integrated with personalized ventilation in hot and humid climate

    DEFF Research Database (Denmark)

    Li, Ruixin; Sekhar, S.C.; Melikov, Arsen Krikor

    2010-01-01

    The potential for improving occupants' thermal comfort with personalized ventilation (PV) system combined with under-floor air distribution (UFAD) system was explored through human response study. The hypothesis was that cold draught at feet can be reduced when relatively warm air is supplied...

  16. Installation system for ceramic self-ventilated roofs and facades called: SKIN-KER; Sistema para la instalacion de cubiertas y fachadas ceramicas autoventiladas denominado: SKIN-KER

    Energy Technology Data Exchange (ETDEWEB)

    Puerta Lopez, A.; Casanova Ramon-Borja, A.

    2012-07-01

    The Company Tejas Borja S.A.U. has been awarded by the Spanish Ceramic and Glass Society with the 2012 Golden Alfa Pize for its research in the development of an installation system that creates a self-ventilated roof with modified red body porcelain tiles, and make it extended to a ventilated facade, allowing the entire house wrap with the same quality and aesthetics. The article describes the various stages of the project design both of individual components as well as verification by simulations and lab testing of the different elements of the system and auxiliary materials involved in the installation. (Author)

  17. Heat Exchanger/Humidifier Trade Study and Conceptual Design for the Constellation Space Suit Portable Life Support System Ventilation Subsystem

    Science.gov (United States)

    Paul, Heather L.; Sompayrac, Robert; Conger, Bruce; Chamberlain, Mateo

    2009-01-01

    As development of the Constellation Space Suit Element progresses, designing the most effective and efficient life support systems is critical. The baseline schematic analysis for the Portable Life Support System (PLSS) indicates that the ventilation loop will need some method of heat exchange and humidification prior to entering the helmet. A trade study was initiated to identify the challenges associated with conditioning the spacesuit breathing gas stream for temperature and water vapor control, to survey technological literature and resources on heat exchanger and humidifiers to provide solutions to the problems of conditioning the spacesuit breathing gas stream, and to propose potential candidate technologies to perform the heat exchanger and humidifier functions. This paper summarizes the results of this trade study and also describes the conceptual designs that NASA developed to address these issues.

  18. Subjective study of thermal acceptability of novel enhanced displacement ventilation system and implication of occupants' personal control

    DEFF Research Database (Denmark)

    Sun, Weimeng; Cheong, K.W.D.; Melikov, Arsen Krikor

    2012-01-01

    A novel air distribution principle of cooler air near the floor level being propelled upward via four fans mounted at each corner of a chair was developed to enhance the performance of conventional displacement ventilation (DV) system. Experiments were conducted in a well-controlled climate chamber...... with DV and constant heat load at different supply air temperatures, namely 20, 22, and 24 °C and room air temperatures, 22, 24, and 26 °C. Subjective assessments were carried out with 32 tropically-acclimatized college students who were given the choice to adjust the fan speed. Subjects' thermal comfort...... of 22 and 24 °C when the fans were in operation. It was also found that the Whole Body Thermal Sensation (WBTS) reported by the subjects was correlated with the Local Thermal Sensation (LTS) at the waist, the arms, the calf and the feet when the novel DV system was employed. An expression which allows...

  19. GTP-W - the ventilation planning module of the GTP system; GTP-W - Das wettertechnische Planungsmodul des GTP-Systems

    Energy Technology Data Exchange (ETDEWEB)

    Langefeld, O. [Technische Univ. Clausthal, Clausthal-Zellerfeld (Germany). Inst. fuer Bergbau; Guder, R. [Deutsche Steinkohle AG, Herne (Germany); Reinartz, A. [XGraphic Ingenieurgesellschaft mbH, Aachen (Germany); Huenefeld, R. [Technische Hochschule Aachen (Germany). Lehrstuhl und Inst. fuer Bergwerks- und Huettenmaschinenkunde

    2001-11-08

    The geometrical technical planning at the DSK consists of several calculation modules and a graphic module as well as the material and information management. This has already been described in detail in this publication. The ventilation planning module (GTP-W) is a further module in this planning system. The individual partial modules Ventilation network planning with the applications 'lod roadway network/mine layout' and 'network planning', 'positioning of ventilation equipment and symbols', the 'main ventilation manual and the fire upthrust calculation' are described. Inter alia the graphic plan compilation and the differences from the predecessor system GRUBE-W are highlighted. The series of publications concerning geometrical technical planning is thus completed for the time being. The module for support technology still in the introductory and development phase will be described later. (orig.) [German] Die Geometrisch-Technische-Planung bei der DSK besteht aus einigen Berechnungs- und einem graphischen Modul sowie dem Material- und Informationsmanagement. Hierueber wurde an dieser Stelle bereits ausfuehrlich berichtet. Das wettertechnische Planungsmodul (GTP-W) ist ein weiterer Baustein in diesem Planungssystem. Beschrieben werden die einzelnen Teilmodule Wetternetzplanung mit den Anwendungen 'Streckennetz/Grubengebaeude laden' und 'Netzplanung', 'Positionierung von wettertechnischen Betriebsmitteln und Symbolen', das 'Hauptwetterbuch' und die 'Brandauftriebsberechnung'. Herausgestellt werden unter anderem die graphische Planerstellung und die Unterschiede zum Vorlaeufersystem GRUBE-W. Damit ist die Veroeffentlichungsreihe ueber die Geometrisch-Technische-Planung zunaechst beendet. Das noch in der Einfuehrungs- und Entwicklungsphase befindliche Modul zur Ausbautechnik wird spaeter vorgestellt. (orig.)

  20. Purge ventilation operability

    Energy Technology Data Exchange (ETDEWEB)

    Marella, J.R.

    1995-04-10

    A determination of minimum requirements for purge exhaust ventilation system operability has been performed. HLWE and HLW Regulatory Program personnel have evaluated the various scenarios of equipment conditions and HLWE has developed the requirements for purge exhaust systems. This report is provided to document operability requirements to assist Tank Farm personnel to determine whether a system is operable/inoperable and to define required compensatory actions.

  1. Decommissioning of Active Ventilation Systems in a Nuclear R and D Facility to Prepare for Building Demolition (Whiteshell Laboratories Decommissioning Project, Canada) - 13073

    Energy Technology Data Exchange (ETDEWEB)

    Wilcox, Brian; May, Doug; Howlett, Don; Bilinsky, Dennis [Atomic Energy of Canada Limited, Ara Mooradian Way, Pinawa, Manitoba (Canada)

    2013-07-01

    Whiteshell Laboratories (WL) is a nuclear research establishment owned by the Canadian government and operated by Atomic Energy of Canada Limited (AECL) since the early 1960's. WL is currently under a decommissioning license and the mandate is to remediate the nuclear legacy liabilities in a safe and cost effective manner. The WL Project is the first major nuclear decommissioning project in Canada. A major initiative underway is to decommission and demolish the main R and D Laboratory complex. The Building 300 R and D complex was constructed to accommodate laboratories and offices which were mainly used for research and development associated with organic-cooled reactors, nuclear fuel waste management, reactor safety, advanced fuel cycles and other applications of nuclear energy. Building 300 is a three storey structure of approximately 16,000 m{sup 2}. In order to proceed with building demolition, the contaminated systems inside the building have to be characterized, removed, and the waste managed. There is a significant focus on volume reduction of radioactive waste for the WL project. The active ventilation system is one of the significant contaminated systems in Building 300 that requires decommissioning and removal. The active ventilation system was designed to manage hazardous fumes and radioactivity from ventilation devices (e.g., fume hoods, snorkels and glove boxes) and to prevent the escape of airborne hazardous material outside of the laboratory boundary in the event of an upset condition. The system includes over 200 ventilation devices and 32 active exhaust fan units and high efficiency particulate air (HEPA) filters. The strategy to remove the ventilation system was to work from the laboratory end back to the fan/filter system. Each ventilation duct was radiologically characterized. Fogging was used to minimize loose contamination. Sections of the duct were removed by various cutting methods and bagged for temporary storage prior to disposition

  2. Short-term airing by natural ventilation

    DEFF Research Database (Denmark)

    Perino, Marco; Heiselberg, Per

    2009-01-01

    traditional mechanical ventilation components with natural ventilation devices, such as motorized windows and louvers. Among the various ventilation strategies that are currently available, buoyancy driven single-sided natural ventilation has proved to be very effective and can provide high air change rates...... that was aimed at developing and validating numerical models for the analysis of buoyancy driven single-sided natural ventilation systems. Once validated, these models can be used to optimize control strategies in order to achieve satisfactory indoor comfort conditions and IAQ.......The need to improve the energy efficiency of buildings requires new and more efficient ventilation systems. It has been demonstrated that innovative operating concepts that make use of natural ventilation seem to be more appreciated by occupants. This kind of system frequently integrates...

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

    Science.gov (United States)

    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. PMID:23119152

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

    Directory of Open Access Journals (Sweden)

    Eduardo Mireles-Cabodevila

    2012-01-01

    Full Text Available 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.

  5. Robust and Stable Disturbance Observer of Servo System for Low-Speed Operation

    DEFF Research Database (Denmark)

    Lee, Kyo Beum; Blaabjerg, Frede

    2007-01-01

    A new scheme to estimate the moment of inertia in the servo motor drive system in very low speed is proposed in this paper. The speed estimation scheme in most servo drive systems for low-speed operation is sensitive to the variation of machine parameter, especially the moment of inertia....... To estimate the motor inertia value, the observer using the Radial Basis Function Network (RBFN) is applied. A control law for stabilizing the system and adaptive laws for updating both of the weights in the RBFN and a bounding constant are established so that the whole closed-loop system is stable...

  6. Comparison of the Mapleson C system and adult and paediatric self-inflating bags for delivering guideline-consistent ventilation during simulated adult cardiopulmonary resuscitation.

    Science.gov (United States)

    Sherren, P B; Lewinsohn, A; Jovaisa, T; Wijayatilake, D S

    2011-07-01

    There is a discrepancy between resuscitation teaching and witnessed clinical practice. Furthermore, deleterious outcomes are associated with hyperventilation. We therefore conducted a manikin-based study of a simulated cardiac arrest to evaluate the ability of three ventilating devices to provide guideline-consistent ventilation. Mean (SD) minute ventilation was reduced with the paediatric self-inflating bag (7.0 (3.2) l.min⁻¹) compared with the Mapleson C system (9.8 (3.5) l.min⁻¹) and adult self-inflating bag (9.7 (4.2) l.min⁻¹ ; p = 0.003). Tidal volume was also lower with the paediatric self-inflating bag (391 (52) ml) compared with the others (582 (87) ml and 625 (103) ml, respectively; p < 0.001), as was peak airway pressure (14.5 (5.2) cmH₂O vs 20.7 (9.0) cmH₂O and 30.3 (11.4) cmH₂O, respectively; p < 0.001). Participants hyperventilated patients' lungs in simulated cardiac arrest with all three devices. The paediatric self-inflating bag delivered the most guideline-consistent ventilation. Its use in adult cardiopulmonary resuscitation may ensure delivery of more guideline-consistent ventilation in patients with tracheal intubation. © 2011 The Authors. Anaesthesia © 2011 The Association of Anaesthetists of Great Britain and Ireland.

  7. Evaluation of Heating, Ventilation, and Air conditioning (HVAC System Performance in an Administrative Building in Tehran (Iran

    Directory of Open Access Journals (Sweden)

    H. Mari Oriyad

    2014-09-01

    Full Text Available Introduction: One of the factors influencing on indoor air quality of the buildings is performance of HVAC (heating, ventilation, and air conditioning systems. These systems supply clean and odorless air, with temperature, humidity, and air velocity within comfort ranges for the residents. The aim of this study was to evaluate performance HVAC system in an administrative building in Tehran. .Material and Method: A questionnaire, developed in their research was used to assess the building occupants’ perception about the performance of HVAC system. To evaluate the performance of HVAC systems, air velocities were measured in the diffusers using a thermal anemometer. Moreover, CO2 concentration, air temperature and relative humidity were measured in the whole floors of the building. Air distribution inside the building was evaluated using smoke test. .Results: Most of the studied people complained about the direction of airflow, thermal conditions and cigarette odor. The highest level of carbon dioxide was measured at 930 ppm inside the restaurant. The maximum and minimum air temperatures and relative humidity were measured 28.3-13.8° C and 28.4-23% respectively. Smoke test showed that the air distribution/direction wasn’t suitable in one third of air diffusers. .Conclusion: Improper air distribution / direction was the main problem with the studied HVAC system which could be corrected by adjusting and balancing of the system.

  8. Displacement Ventilation

    DEFF Research Database (Denmark)

    Bjørn, Erik; Mattsson, Magnus; Sandberg, Mats

    Full-scale experiments were made in a displacement ventilated room with two breathing thermal manikins to study the effect of movements and breathing on the vertical contaminant distribution, and on the personal exposure of occupants. Concentrations were measured with tracer gas equipment...... in the room and in the inhalation of both manikins. Tracer gas was added in the heat plume above a sitting manikin, or in the exhalation through either the nose or the mouth. The other manikin moved back and forth at different speeds on a low trolley. The mentioned experimental conditions have a significant...

  9. Kitchen ventilation

    Energy Technology Data Exchange (ETDEWEB)

    Kelso, R.M. [Univ. of Tennessee, Knoxville, TN (United States). College of Architecture; Rousseau, C. [Newcomb and Boyd Consulting Engineers, Atlanta, GA (United States)

    1995-09-01

    Kitchen ventilation is a subject that has not received the attention that has been given to more glamorous HVAC and R topics. Consequently, its theoretical and technical development has not advanced like these topics. However, a group has been working within the ASHRAE Technical Committee (TC) and Task Group (TG) framework to correct this situation. The group is TG5.KV and it achieved TG status last year after starting as an informal group and then a sub-committee of TC9.8. One of its efforts has been to write a Handbook chapter, which will appear in the 1995 ASHRAE Handbook -- Applications. This article is a survey of that chapter.

  10. Effects of pressure-controlled and volume-controlled ventilation on respiratory mechanics and systemic stress response during prone position.

    Science.gov (United States)

    Sen, Oznur; Bakan, Mefkur; Umutoglu, Tarik; Aydın, Nurdan; Toptas, Mehmet; Akkoc, Ibrahim

    2016-01-01

    Prone position during general anesthesia for special surgical operations may be related with increased airway pressure, decreased pulmonary and thoracic compliance that may be explained by restriction of chest expansion and compression of abdomen. The optimum ventilation mode for anesthetized patients on prone position was not described and studies comparing volume-controlled ventilation (VCV) and pressure-controlled ventilation (PCV) during prone position are limited. We hypothesized that PCV instead of VCV during prone position could achieve lower airway pressures and reduce the systemic stress response. In this study, we aimed to compare the effects of PCV and VCV modes during prone position on respiratory mechanics, oxygenation, and hemodynamics, as well as blood cortisol and insulin levels, which has not been investigated before. Fifty-four ASA I-II patients, 18-70 years of age, who underwent percutaneous nephrolithotomy on prone position, were randomly selected to receive either the PCV (Group PC, n = 27) or VCV (Group VC, n = 27) under general anesthesia with sevoflurane and fentanyl. Blood sampling was made for baseline arterial blood gases (ABG), cortisol, insulin, and glucose levels. After anesthesia induction and endotracheal intubation, patients in Group PC were given pressure support to form 8 mL/kg tidal volume and patients in Group VC was maintained at 8 mL/kg tidal volume calculated using predicted body weight. All patients were maintained with 5 cmH2O PEEP. Respiratory parameters were recorded during supine and prone position. Assessment of ABG and sampling for cortisol, insulin and glucose levels were repeated during surgery and 60 min after extubation. P-peak and P-plateau levels during supine and prone positions were significantly higher and P-mean and compliance levels during prone position were significantly lower in Group VC when compared with Group PC. Postoperative PaO2 level was significantly higher in Group PC compared with Group

  11. New regulatory requirements of HVAC ventilation systems in nuclear installations Spanish; Nuevos requisitos reguladores de los sistemas de ventilacion HVAC en instalaciones nucleares espanolas

    Energy Technology Data Exchange (ETDEWEB)

    Sierra, J. J.

    2011-07-01

    Ventilation systems serve a number of functions vital to the safe operation of nuclear facilities: the renewal of air, cooling components, prevent the release of contaminated air into the environment under both normal operating and accident, or ensure habitability of the control rooms in all situations.

  12. The Maintenance of Heating, Ventilating and Air-Conditioning Systems and Indoor Air Quality in Schools: A Guide for School Facility Managers. Technical Bulletin.

    Science.gov (United States)

    Wheeler, Arthur E.

    To help maintain good indoor air quality (IAQ) in schools, guidance for the development and implementation of an effective program for maintenance and operation of heating, ventilating, and air-conditioning (HVAC) systems are discussed. Frequently, a building's occupants will complain about IAQ when the temperature or humidity are at uncomfortable…

  13. Demand controlled ventilation in a bathroom

    DEFF Research Database (Denmark)

    Mortensen, Dorthe Kragsig; Nielsen, Toke Rammer; Topp, Claus

    2008-01-01

    consumption during periods where the demand for ventilation is low and poor indoor climate during periods where the demand for ventilation is high. Controlling the ventilation rate by demand can improve the energy performance of the ventilation system and the indoor climate. This paper compares the indoor...... climate and energy consumption of a Constant Air Volume (CAV) system and a Demand Controlled Ventilation (DCV) system for two different bathroom designs. The air change rate of the CAV system corresponded to 0.5h-1. The ventilation rate of the DCV system was controlled by occupancy and by the relative....... The indoor climate and the energy consumption were estimated based on a simplified calculation of the variation of the water content within the bathroom during a day. The results showed that the DCV system controlled by occupancy and relative humidity had an improved energy performance and an improved indoor...

  14. Error Analysis of the K-Rb-21Ne Comagnetometer Space-Stable Inertial Navigation System.

    Science.gov (United States)

    Cai, Qingzhong; Yang, Gongliu; Quan, Wei; Song, Ningfang; Tu, Yongqiang; Liu, Yiliang

    2018-02-24

    According to the application characteristics of the K-Rb- 21 Ne comagnetometer, a space-stable navigation mechanization is designed and the requirements of the comagnetometer prototype are presented. By analysing the error propagation rule of the space-stable Inertial Navigation System (INS), the three biases, the scale factor of the z -axis, and the misalignment of the x - and y -axis non-orthogonal with the z -axis, are confirmed to be the main error source. A numerical simulation of the mathematical model for each single error verified the theoretical analysis result of the system's error propagation rule. Thus, numerical simulation based on the semi-physical data result proves the feasibility of the navigation scheme proposed in this paper.

  15. Performance of personalized ventilation in a room with an underfloor air distribution system: transport of contaminants between occupants

    DEFF Research Database (Denmark)

    Cermak, Radim; Melikov, Arsen Krikor

    2003-01-01

    Studies have documented that personalized ventilation, which provides clean air at each office workplace, is able to improve substantially the quality of air inhaled by occupants. However, the interaction between the airflow generated by personalized ventilation and the airflow pattern outside th...

  16. A 3D Fractional-Order Chaotic System with Only One Stable Equilibrium and Controlling Chaos

    Directory of Open Access Journals (Sweden)

    Shiyun Shen

    2017-01-01

    Full Text Available One 3D fractional-order chaotic system with only one locally asymptotically stable equilibrium is reported. To verify the chaoticity, the maximum Lyapunov exponent (MAXLE with respect to the fractional-order and chaotic attractors are obtained by numerical calculation for this system. Furthermore, by linear scalar controller consisting of a single state variable, one control scheme for stabilization of the 3D fractional-order chaotic system is suggested. The numerical simulations show the feasibility of the control scheme.

  17. Stochastic resonance in an ensemble of bistable systems under stable distribution noises and nonhomogeneous coupling

    Science.gov (United States)

    Tang, Yang; Zou, Wei; Lu, Jianquan; Kurths, Jürgen

    2012-04-01

    In this paper, stochastic resonance of an ensemble of coupled bistable systems driven by noise having an α-stable distribution and nonhomogeneous coupling is investigated. The α-stable distribution considered here is characterized by four intrinsic parameters: α∈(0,2] is called the stability parameter for describing the asymptotic behavior of stable densities; β∈[-1,1] is a skewness parameter for measuring asymmetry; γ∈(0,∞) is a scale parameter for measuring the width of the distribution; and δ∈(-∞,∞) is a location parameter for representing the mean value. It is demonstrated that the resonant behavior is optimized by an intermediate value of the diversity in coupling strengths. We show that the stability parameter α and the scale parameter γ can be well selected to generate resonant effects in response to external signals. In addition, the interplay between the skewness parameter β and the location parameter δ on the resonance effects is also studied. We further show that the asymmetry of a Lévy α-stable distribution resulting from the skewness parameter β and the location parameter δ can enhance the resonance effects. Both theoretical analysis and simulation are presented to verify the results of this paper.

  18. Characterizing different spring systems in the Berchtesgaden Alps using stable water isotopes

    Science.gov (United States)

    Garvelmann, Jakob; Warscher, Michael; Franz, Helmut; Lotz, Annette; Kunstmann, Harald

    2016-04-01

    An extensive sampling campaign was started in January 2012 in the Berchtesgaden Alps located in the southeast of Germany. Monthly samples at 8 springs, 5 stream gauges and bulk samples of precipitation at 7 sites were collected since then. The samples were analyzed for the stable water isotopes oxygen-18 and deuterium. The sampled water systems are characterized by very different dynamics of the stable isotope signatures. Time series of precipitation stable isotope signatures were derived from the GNIP dataset in order to extend the dataset beyond the start of the sampling campaign. Mean residence times (MRT) of the spring systems and surface water streams were calculated using the exponential model and the sine curve approach. Both approaches yield very similar MRT for the studied water systems. Based on this analysis two groups of spring systems could be identified. One group with relatively short MRT of 1-2 years and another group with longer MRT of about 10-12 years. Those results were consequently discussed and interpreted in the context of a large body of literature existing on the hydrogeology in the Berchtesgaden Alps area. The springs characterized by short MRT are located in geological situations with karstified limestone, dolomite or shell limestone. Previous dye tracer experiments in those areas revealed very efficient drainage systems with fast flowpaths. The spring systems with longer MRT are located in areas with large bodies consisting of quaternary debris and talus material and can be considered as porous aquifers with relatively long flow paths with low flow velocities. The influence of the stable isotope signature and hence the MRT observed at the springs is also reflected in the downstream surface water stable isotope signatures showing the importance of the spring water for river discharge in the study area. The results of the study provide interesting insights into the different dynamics of spring systems and surface water bodies controlled by

  19. Boundary conditions for the use of personal ventilation over mixing ventilation in open plan offices

    DEFF Research Database (Denmark)

    Petersen, Steffen; Hviid, Christian Anker

    2013-01-01

    This paper investigates the boundary conditions for choosing a combined Personal Ventilation (PV) and Mixing Ventilation (MV) over conventional mixing ventilation in an office with multiple workers. A simplified procedure for annual performance assessment of PV/MV systems in terms of air quality,...

  20. Contaminant Distribution Around Persons in Rooms Ventilated by Displacement Ventilation

    DEFF Research Database (Denmark)

    Brohus, Henrik; Nielsen, Peter V.

    An optimal design of the ventilation system needs a proper prediction of the velocity, temperature and contaminant distribution in the room. Traditionally this is done either by the use of simplified models or by a somewhat more comprehensive CFD-simulation. Common to both methods is usually the ...... the lack of consideration for the persons present in the room. This paper deals with some of the effects of persons present in a displacement ventilated room, especially the effect on the contaminant distribution....

  1. Application of acoustic agglomeration to enhance air filtration efficiency in air-conditioning and mechanical ventilation (ACMV) systems

    Science.gov (United States)

    Xiong, Jin Wen; Wan, Man Pun

    2017-01-01

    The recent episodes of haze in Southeast Asia have caused some of the worst regional atmospheric pollution ever recorded in history. In order to control the levels of airborne fine particulate matters (PM) indoors, filtration systems providing high PM capturing efficiency are often sought, which inadvertently also results in high airflow resistance (or pressure drop) that increases the energy consumption for air distribution. A pre-conditioning mechanism promoting the formation of particle clusters to enhance PM capturing efficiency without adding flow resistance in the air distribution ductwork could provide an energy-efficient solution. This pre-conditioning mechanism can be fulfilled by acoustic agglomeration, which is a phenomenon that promotes the coagulation of suspended particles by acoustic waves propagating in the fluid medium. This paper discusses the basic mechanisms of acoustic agglomeration along with influencing factors that could affect the agglomeration efficiency. The feasibility to apply acoustic agglomeration to improve filtration in air-conditioning and mechanical ventilation (ACMV) systems is investigated experimentally in a small-scale wind tunnel. Experimental results indicate that this novel application of acoustic pre-conditioning improves the PM2.5 filtration efficiency of the test filters by up to 10% without introducing additional pressure drop. The fan energy savings from not having to switch to a high capturing efficiency filter largely outstrip the additional energy consumed by the acoustics system. This, as a whole, demonstrates potential energy savings from the combined acoustic-enhanced filtration system without compromising on PM capturing efficiency. PMID:28594862

  2. Application of acoustic agglomeration to enhance air filtration efficiency in air-conditioning and mechanical ventilation (ACMV systems.

    Directory of Open Access Journals (Sweden)

    Bing Feng Ng

    Full Text Available The recent episodes of haze in Southeast Asia have caused some of the worst regional atmospheric pollution ever recorded in history. In order to control the levels of airborne fine particulate matters (PM indoors, filtration systems providing high PM capturing efficiency are often sought, which inadvertently also results in high airflow resistance (or pressure drop that increases the energy consumption for air distribution. A pre-conditioning mechanism promoting the formation of particle clusters to enhance PM capturing efficiency without adding flow resistance in the air distribution ductwork could provide an energy-efficient solution. This pre-conditioning mechanism can be fulfilled by acoustic agglomeration, which is a phenomenon that promotes the coagulation of suspended particles by acoustic waves propagating in the fluid medium. This paper discusses the basic mechanisms of acoustic agglomeration along with influencing factors that could affect the agglomeration efficiency. The feasibility to apply acoustic agglomeration to improve filtration in air-conditioning and mechanical ventilation (ACMV systems is investigated experimentally in a small-scale wind tunnel. Experimental results indicate that this novel application of acoustic pre-conditioning improves the PM2.5 filtration efficiency of the test filters by up to 10% without introducing additional pressure drop. The fan energy savings from not having to switch to a high capturing efficiency filter largely outstrip the additional energy consumed by the acoustics system. This, as a whole, demonstrates potential energy savings from the combined acoustic-enhanced filtration system without compromising on PM capturing efficiency.

  3. Application of acoustic agglomeration to enhance air filtration efficiency in air-conditioning and mechanical ventilation (ACMV) systems.

    Science.gov (United States)

    Ng, Bing Feng; Xiong, Jin Wen; Wan, Man Pun

    2017-01-01

    The recent episodes of haze in Southeast Asia have caused some of the worst regional atmospheric pollution ever recorded in history. In order to control the levels of airborne fine particulate matters (PM) indoors, filtration systems providing high PM capturing efficiency are often sought, which inadvertently also results in high airflow resistance (or pressure drop) that increases the energy consumption for air distribution. A pre-conditioning mechanism promoting the formation of particle clusters to enhance PM capturing efficiency without adding flow resistance in the air distribution ductwork could provide an energy-efficient solution. This pre-conditioning mechanism can be fulfilled by acoustic agglomeration, which is a phenomenon that promotes the coagulation of suspended particles by acoustic waves propagating in the fluid medium. This paper discusses the basic mechanisms of acoustic agglomeration along with influencing factors that could affect the agglomeration efficiency. The feasibility to apply acoustic agglomeration to improve filtration in air-conditioning and mechanical ventilation (ACMV) systems is investigated experimentally in a small-scale wind tunnel. Experimental results indicate that this novel application of acoustic pre-conditioning improves the PM2.5 filtration efficiency of the test filters by up to 10% without introducing additional pressure drop. The fan energy savings from not having to switch to a high capturing efficiency filter largely outstrip the additional energy consumed by the acoustics system. This, as a whole, demonstrates potential energy savings from the combined acoustic-enhanced filtration system without compromising on PM capturing efficiency.

  4. A xenon recirculating ventilator for the newborn piglet: developing clinical applications of xenon for neonates.

    Science.gov (United States)

    Faulkner, Stuart D; Downie, Neil A; Mercer, Christopher J; Kerr, Stuart A; Sanders, Robert D; Robertson, Nicola J

    2012-12-01

    The clinical applications of xenon for the neonate include both anaesthesia and neuroprotection. However, due to the limited natural availability of xenon, special equipment is required to administer and recapture the gas to develop xenon as a therapeutic agent. In order to test the xenon recirculating ventilator for the application of neuroprotection in a preclinical trial, our primary objective was to test the efficiency, reliability and safety of administering 50% xenon for 24 h in hypoxic ischaemic piglets. A prospective observational study. Institute for Women's Health, University College London, January 2008 to March 2008. Four anaesthetised male piglets, less than 24 h old, underwent a global hypoxic ischaemic insult for approximately 25 min prior to switching to the xenon recirculating ventilator. Between 2 and 26 h after hypoxic ischaemia, anaesthetised piglets were administered a mixture of 50% xenon, air, oxygen and isoflurane. The primary outcome measure was blood gas PaCO2 (kPa) and secondary outcome measure was xenon gas use (l h), over the 24-h duration of xenon administration. The xenon recirculating ventilator provided effective ventilation, automated control of xenon/air gas mixtures, and stable blood gas PaCO2 (4.5 to 6.3 kPa) for 24 h of ventilation with the xenon recirculating ventilator. Total xenon use was minimal at approximately 0.6 l h at a cost of approximately &OV0556;8 h. Additional features included an isoflurane scavenger and bellows height alarm. Stable gas delivery to a piglet with minimal xenon loss and analogue circuitry made the xenon recirculating ventilator easy to use and it could be modified for other large animals and noble gas mixtures. The technologies, safety and efficiency of xenon delivery in this preclinical system have been taken forward in the development of neonatal ventilators for clinical use in phase II clinical trials for xenon-augmented hypothermia and for xenon anaesthesia.

  5. Diffuse Ceiling Ventilation

    DEFF Research Database (Denmark)

    Zhang, Chen; Yu, Tao; Heiselberg, Per Kvols

    -cooling period and night cooling potential. The investment cost of this ventilation system is about 5-10% lower than the conventional ones, because the acoustic ceiling could be directly applied as air diffuser and the use of plenum to distribute air reduces the cost of ductwork. There is a growing interest...... and manufacturers and the users of diffuse ceiling technology. The design guide introduces the principle and key characteristics of room air distribution with diffuse ceiling ventilation. It provides an overview of potential benefit and limitations of this technology. The benefits include high thermal comfort, high...... cooling capacity, energy saving, low investment cost and low noise level; while the limitations include condensation risk and the limit on the room geometry. Furthermore, the crucial design parameters are summarized and their effects on the system performance are discussed. In addition to the stand...

  6. Passivity-Based Automated Design of Stable Multi-Feedback Distributed Power Delivery Systems

    Science.gov (United States)

    2017-03-01

    performan pically determ C gain, phase stributed on- delivering hig ce systems. S n automated delivery is pr is designe fabricated in performance a n-chip...termined by t In systems w igure 1, the se no straig table loop. An een proposed the power g design proces this work b on with a pa iques...Performan ce of an i ined by a se margin, DC o chip power h quality pow tability is a pr design flow f oposed. A dis d based on 28 nm CMO nd stable

  7. Adaptive PID Controller Using RLS for SISO Stable and Unstable Systems

    Directory of Open Access Journals (Sweden)

    Rania A. Fahmy

    2014-01-01

    Full Text Available The proportional-integral-derivative (PID is still the most common controller and stabilizer used in industry due to its simplicity and ease of implementation. In most of the real applications, the controlled system has parameters which slowly vary or are uncertain. Thus, PID gains must be adapted to cope with such changes. In this paper, adaptive PID (APID controller is proposed using the recursive least square (RLS algorithm. RLS algorithm is used to update the PID gains in real time (as system operates to force the actual system to behave like a desired reference model. Computer simulations are given to demonstrate the effectiveness of the proposed APID controller on SISO stable and unstable systems considering the presence of changes in the systems parameters.

  8. A stable systemic risk ranking in China's banking sector: Based on principal component analysis

    Science.gov (United States)

    Fang, Libing; Xiao, Binqing; Yu, Honghai; You, Qixing

    2018-02-01

    In this paper, we compare five popular systemic risk rankings, and apply principal component analysis (PCA) model to provide a stable systemic risk ranking for the Chinese banking sector. Our empirical results indicate that five methods suggest vastly different systemic risk rankings for the same bank, while the combined systemic risk measure based on PCA provides a reliable ranking. Furthermore, according to factor loadings of the first component, PCA combined ranking is mainly based on fundamentals instead of market price data. We clearly find that price-based rankings are not as practical a method as fundamentals-based ones. This PCA combined ranking directly shows systemic risk contributions of each bank for banking supervision purpose and reminds banks to prevent and cope with the financial crisis in advance.

  9. Capability of air filters to retain airborne bacteria and molds in heating, ventilating and air-conditioning (HVAC) systems.

    Science.gov (United States)

    Möritz, M; Peters, H; Nipko, B; Rüden, H

    2001-07-01

    The capability of air filters (filterclass: F6, F7) to retain airborne outdoor microorganisms was examined in field experiments in two heating, ventilating and air conditioning (HVAC) systems. At the beginning of the 15-month investigation period, the first filter stages of both HVAC systems were equipped with new unused air filters. The number of airborne bacteria and molds before and behind the filters were determined simultaneously in 14 days-intervals using 6-stage Andersen cascade impactors. Under relatively dry ( 12 degrees C) outdoor air conditions air filters led to a marked reduction of airborne microorganism concentrations (bacteria by approximately 70% and molds by > 80%). However, during long periods of high relative humidity (> 80% R. H.) a proliferation of bacteria on air filters with subsequent release into the filtered air occurred. These microorganisms were mainly smaller than 1.1 microns therefore being part of the respirable fraction. The results showed furthermore that one possibility to avoid microbial proliferation is to limit the relative humidity in the area of the air filters to 80% R. H. (mean of 3 days), e.g. by using preheaters in front of air filters in HVAC-systems.

  10. Stable Imaging and Accuracy Issues of Low-Altitude Unmanned Aerial Vehicle Photogrammetry Systems

    Directory of Open Access Journals (Sweden)

    Ying Yang

    2016-04-01

    Full Text Available Stable imaging of an unmanned aerial vehicle (UAV photogrammetry system is an important issue that affects the data processing and application of the system. Compared with traditional aerial images, the large rotation of roll, pitch, and yaw angles of UAV images decrease image quality and result in image deformation, thereby affecting the ground resolution, overlaps, and the consistency of the stereo models. These factors also cause difficulties in automatic tie point matching, image orientation, and accuracy of aerial triangulation (AT. The issues of large-angle photography of UAV photogrammetry system are discussed and analyzed quantitatively in this paper, and a simple and lightweight three-axis stabilization platform that works with a low-precision integrated inertial navigation system and a three-axis mechanical platform is used to reduce this problem. An experiment was carried out with an airship as the flight platform. Another experimental dataset, which was acquired by the same flight platform without a stabilization platform, was utilized for a comparative test. Experimental results show that the system can effectively isolate the swing of the flying platform. To ensure objective and reliable results, another group of experimental datasets, which were acquired using a fixed-wing UAV platform, was also analyzed. Statistical results of the experimental datasets confirm that stable imaging of a UAV platform can help improve the quality of aerial photography imagery and the accuracy of AT, and potentially improve the application of images acquired by a UAV.

  11. Hygiene guideline for the planning, installation, and operation of ventilation and air-conditioning systems in health-care settings – Guideline of the German Society for Hospital Hygiene (DGKH

    Directory of Open Access Journals (Sweden)

    Külpmann, Rüdiger

    2016-02-01

    Full Text Available Since the publication of the first “Hospital Hygiene Guideline for the implementation and operation of air conditioning systems (HVAC systems in hospitals” ( in 2002, it was necessary due to the increase in knowledge, new regulations, improved air-conditioning systems and advanced test methods to revise the guideline. Based on the description of the basic features of ventilation concepts, its hygienic test and the usage-based requirements for ventilation, the DGKH section “Ventilation and air conditioning technology” attempts to provide answers for the major air quality issues in the planning, design and the hygienically safe operation of HVAC systems in rooms of health care.

  12. A manual for a Laboratory Information Management System (LIMS) for light stable isotopes

    Science.gov (United States)

    Coplen, Tyler B.

    1998-01-01

    The reliability and accuracy of isotopic data can be improved by utilizing database software to (i) store information about samples, (ii) store the results of mass spectrometric isotope-ratio analyses of samples, (iii) calculate analytical results using standardized algorithms stored in a database, (iv) normalize stable isotopic data to international scales using isotopic reference materials, and (v) generate multi-sheet paper templates for convenient sample loading of automated mass-spectrometer sample preparation manifolds. Such a database program is presented herein. Major benefits of this system include (i) an increase in laboratory efficiency, (ii) reduction in the use of paper, (iii) reduction in workload due to the elimination or reduction of retyping of data by laboratory personnel, and (iv) decreased errors in data reported to sample submitters. Such a database provides a complete record of when and how often laboratory reference materials have been analyzed and provides a record of what correction factors have been used through time. It provides an audit trail for stable isotope laboratories. Since the original publication of the manual for LIMS for Light Stable Isotopes, the isotopes 3 H, 3 He, and 14 C, and the chlorofluorocarbons (CFCs), CFC-11, CFC-12, and CFC-113, have been added to this program.

  13. Applications of computational fluid dynamics (CFD) in the modelling and design of ventilation systems in the agricultural industry: a review.

    Science.gov (United States)

    Norton, Tomás; Sun, Da-Wen; Grant, Jim; Fallon, Richard; Dodd, Vincent

    2007-09-01

    The application of computational fluid dynamics (CFD) in the agricultural industry is becoming ever more important. Over the years, the versatility, accuracy and user-friendliness offered by CFD has led to its increased take-up by the agricultural engineering community. Now CFD is regularly employed to solve environmental problems of greenhouses and animal production facilities. However, due to a combination of increased computer efficacy and advanced numerical techniques, the realism of these simulations has only been enhanced in recent years. This study provides a state-of-the-art review of CFD, its current applications in the design of ventilation systems for agricultural production systems, and the outstanding challenging issues that confront CFD modellers. The current status of greenhouse CFD modelling was found to be at a higher standard than that of animal housing, owing to the incorporation of user-defined routines that simulate crop biological responses as a function of local environmental conditions. Nevertheless, the most recent animal housing simulations have addressed this issue and in turn have become more physically realistic.

  14. Heat flux to the helium cryogenic system elements in the case of incidental vacuum vessel ventilation with atmospheric air

    CERN Multimedia

    CERN. Geneva

    2016-01-01

    The selection process for size in safety equipment for cold vessels or process pipes in cryogenic systems should take into consideration the incidental ventilation of the vacuum vessel with atmospheric air. In this case, a significant heat input toward the cold elements of the system can be expected. A number of experimental investigations have been done for the elements at liquid helium temperature which have been covered with 10 layers of MLI. The typical values of the heat flux were measured in a range of 3.7 to 5.0 kW/m2 of the element surface. The helium temperature parts are typically surrounded by thermal shields that are kept in a temperature range of 50-80K. On the external side, the thermal shields are covered with 30-40 layers of MLI while on the internal side, the shields are bare. The theoretical calculations of heat flux to the thermal shield, with respect to the possibility of air condensation and freezing on the bare side of the thermal shield, show that the heat flux to the thermal shield can...

  15. Summary of human responses to ventilation

    Energy Technology Data Exchange (ETDEWEB)

    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

  16. Variable mechanical ventilation

    Science.gov (United States)

    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

  17. Variable mechanical ventilation.

    Science.gov (United States)

    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.

  18. Personalizing mechanical ventilation according to physiologic parameters to stabilize alveoli and minimize ventilator induced lung injury (VILI).

    Science.gov (United States)

    Nieman, Gary F; Satalin, Joshua; Andrews, Penny; Aiash, Hani; Habashi, Nader M; Gatto, Louis A

    2017-12-01

    It has been shown that mechanical ventilation in patients with, or at high-risk for, the development of acute respiratory distress syndrome (ARDS) can be a double-edged sword. If the mechanical breath is improperly set, it can amplify the lung injury associated with ARDS, causing a secondary ventilator-induced lung injury (VILI). Conversely, the mechanical breath can be adjusted to minimize VILI, which can reduce ARDS mortality. The current standard of care ventilation strategy to minimize VILI attempts to reduce alveolar over-distension and recruitment-derecruitment (R/D) by lowering tidal volume (Vt) to 6 cc/kg combined with adjusting positive-end expiratory pressure (PEEP) based on a sliding scale directed by changes in oxygenation. Thus, Vt is often but not always set as a "one-size-fits-all" approach and although PEEP is often set arbitrarily at 5 cmH2O, it may be personalized according to changes in a physiologic parameter, most often to oxygenation. However, there is evidence that oxygenation as a method to optimize PEEP is not congruent with the PEEP levels necessary to maintain an open and stable lung. Thus, optimal PEEP might not be personalized to the lung pathology of an individual patient using oxygenation as the physiologic feedback system. Multiple methods of personalizing PEEP have been tested and include dead space, lung compliance, lung stress and strain, ventilation patterns using computed tomography (CT) or electrical impedance tomography (EIT), inflection points on the pressure/volume curve (P/V), and the slope of the expiratory flow curve using airway pressure release ventilation (APRV). Although many studies have shown that personalizing PEEP is possible, there is no consensus as to the optimal technique. This review will assess various methods used to personalize PEEP, directed by physiologic parameters, necessary to adaptively adjust ventilator settings with progressive changes in lung pathophysiology.

  19. Anammox-zeolite system acting as buffer to achieve stable effluent nitrogen values.

    Science.gov (United States)

    Yapsakli, Kozet; Aktan, Cigdem Kalkan; Mertoglu, Bulent

    2017-02-01

    For a successful nitrogen removal, Anammox process needs to be established in line with a stable partial nitritation pretreatment unit since wastewater influent is mostly unsuitable for direct treatment by Anammox. Partial nitritation is, however, a critical bottleneck for the nitrogen removal since it is often difficult to maintain the right proportions of NO2-N and NH4-N during long periods of time for Anammox process. This study investigated the potential of Anammox-zeolite biofilter to buffer inequalities in nitrite and ammonium nitrogen in the influent feed. Anammox-zeolite biofilter combines the ion-exchange property of zeolite with the biological removal by Anammox process. Continuous-flow biofilter was operated for 570 days to test the response of Anammox-zeolite system for irregular ammonium and nitrite nitrogen entries. The reactor demonstrated stable and high nitrogen removal efficiencies (approximately 95 %) even when the influent NO2-N to NH4-N ratios were far from the stoichiometric ratio for Anammox reaction (i.e. NO2-N to NH4-N ranging from 0 to infinity). This is achieved by the sorption of surplus NH4-N by zeolite particles in case ammonium rich influent came in excess with respect to Anammox stoichiometry. Similarly, when ammonium-poor influent is fed to the reactor, ammonium desorption took place due to shifts in ion-exchange equilibrium and deficient amount were supplied by previously sorbed NH4-N. Here, zeolite acted as a preserving reservoir of ammonium where both sorption and desorption took place when needed and this caused the Anammox-zeolite system to act as a buffer system to generate a stable effluent.

  20. Development of a Residential Integrated Ventilation Controller

    Energy Technology Data Exchange (ETDEWEB)

    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. Variable mechanical ventilation

    OpenAIRE

    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. ...

  2. Displacement Ventilation in a Room with Low-Level Diffusers

    DEFF Research Database (Denmark)

    Nielsen, Peter V.

    Ventilation systems with vertical displacement flow have been used in industrial areas with high thermal loads for many years. Quite resently the vertical displacement flow systems have grown popular as comfort ventilation in rooms with thermal loads e.g. offices.......Ventilation systems with vertical displacement flow have been used in industrial areas with high thermal loads for many years. Quite resently the vertical displacement flow systems have grown popular as comfort ventilation in rooms with thermal loads e.g. offices....

  3. Lung volume recruitment maneuvers and respiratory system mechanics in mechanically ventilated mice.

    Science.gov (United States)

    Cannizzaro, Vincenzo; Berry, Luke J; Nicholls, Philip K; Zosky, Graeme R; Turner, Debra J; Hantos, Zoltán; Sly, Peter D

    2009-12-31

    The study aim was to establish how recruitment maneuvers (RMs) influence lung mechanics and to determine whether RMs produce lung injury. Healthy BALB/c mice were allocated to receive positive end-expiratory pressure (PEEP) at 2 or 6 cmH(2)O and volume- (20 or 40 mL/kg) or pressure-controlled (25 cmH(2)O) RMs every 5 or 75 min for 150 min. The low-frequency forced oscillation technique was used to measure respiratory input impedance. Large RMs resulting in peak airway opening pressures (P(ao))>30 cmH(2)O did not increase inflammatory response or affect transcutaneous oxygen saturation but significantly lowered airway resistance, tissue damping and tissue elastance; the latter changes are likely associated with the bimodal pressure-volume behavior observed in mice. PEEP increase alone and application of RMs producing peak P(ao) below 25 cmH(2)O did not prevent or reverse changes in lung mechanics; whereas frequent application of substantial RMs on top of elevated PEEP levels produced stable lung mechanics without signs of lung injury.

  4. 46 CFR 177.600 - Ventilation of enclosed and partially enclosed spaces.

    Science.gov (United States)

    2010-10-01

    ... ventilation system unless natural ventilation in all ordinary weather conditions is satisfactory to the OCMI... 46 Shipping 7 2010-10-01 2010-10-01 false Ventilation of enclosed and partially enclosed spaces... PASSENGER VESSELS (UNDER 100 GROSS TONS) CONSTRUCTION AND ARRANGEMENT Ventilation § 177.600 Ventilation of...

  5. Stable reduced-order models of generalized dynamical systems using coordinate-transformed Arnoldi algorithms

    Energy Technology Data Exchange (ETDEWEB)

    Silveira, L.M.; Kamon, M.; Elfadel, I.; White, J. [Massachusetts Inst. of Technology, Cambridge, MA (United States)

    1996-12-31

    Model order reduction based on Krylov subspace iterative methods has recently emerged as a major tool for compressing the number of states in linear models used for simulating very large physical systems (VLSI circuits, electromagnetic interactions). There are currently two main methods for accomplishing such a compression: one is based on the nonsymmetric look-ahead Lanczos algorithm that gives a numerically stable procedure for finding Pade approximations, while the other is based on a less well characterized Arnoldi algorithm. In this paper, we show that for certain classes of generalized state-space systems, the reduced-order models produced by a coordinate-transformed Arnoldi algorithm inherit the stability of the original system. Complete Proofs of our results will be given in the final paper.

  6. Particular geoscientific perspectives on stable isotope analysis in the arboreal system

    Science.gov (United States)

    Helle, Gerhard; Balting, Daniel; Pauly, Maren; Slotta, Franziska

    2017-04-01

    In geosciences stable isotopes of carbon, oxygen and hydrogen from the tree ring archive have been used for several decades to trace the course of past environmental and climatological fluctuations. In contrast to ice cores, the tree ring archive is of biological nature (like many other terrestrial archives), but provides the opportunity to establish site networks with very high resolution in space and time. Many of the basic physical mechanisms of isotope shifts are known, but biologically mediated processes may lead to isotope effects that are poorly understood. This implies that the many processes within the arboreal system leading to archived isotope ratios in wood material are governed by a multitude of environmental variables that are not only tied to the isotopic composition of atmospheric source values (precipitation, CO2), but also to seasonally changing metabolic flux rates and pool sizes of photosynthates within the trees. Consequently, the extraction of climate and environmental information is particularly challenging and reconstructions are still of rather qualitative nature. Over the last 10 years or so, monitoring studies have been implemented to investigate stable isotope, climate and environmental signal transfer within the arboreal system to develop transfer or response functions that can translate the relevant isotope values extracted from tree rings into climate or other environmental variables. To what extent have these efforts lead to a better understanding that helps improving the meaningfulness of tree ring isotope signals? For example, do monitoring studies help deciphering the causes for age-related trends in tree ring stable isotope sequences that are published in a growing number of papers. Are existing monitoring studies going into detail enough or is it already too much effort for the outcome? Based on what we know already particularly in mesic habitats, tree ring stable isotopes are much better climate proxies than other tree ring

  7. Effects of pressure-controlled and volume-controlled ventilation on respiratory mechanics and systemic stress response during laparoscopic cholecystectomy.

    Science.gov (United States)

    Sen, Oznur; Umutoglu, Tarik; Aydın, Nurdan; Toptas, Mehmet; Tutuncu, Ayse Cigdem; Bakan, Mefkur

    2016-01-01

    Pressure-controlled ventilation (PCV) is less frequently employed in general anesthesia. With its high and decelerating inspiratory flow, PCV has faster tidal volume delivery and different gas distribution. The same tidal volume setting, delivered by PCV versus volume-controlled ventilation (VCV), will result in a lower peak airway pressure and reduced risk of barotrauma. We hypothesized that PCV instead of VCV during laparoscopic surgery could achieve lower airway pressures and reduce the systemic stress response. Forty ASA I-II patients were randomly selected to receive either the PCV (Group PC, n = 20) or VCV (Group VC, n = 20) during laparoscopic cholecystectomy. Blood sampling was made for baseline arterial blood gases (ABG), cortisol, insulin, and glucose levels. General anesthesia with sevoflurane and fentanyl was employed to all patients. After anesthesia induction and endotracheal intubation, patients in Group PC were given pressure support to form 8 mL/kg tidal volume and patients in Group VC was maintained at 8 mL/kg tidal volume calculated using predicted body weight. All patients were maintained with 5 cmH2O positive-end expiratory pressure (PEEP). Respiratory parameters were recorded before and 30 min after pneumoperitonium. Assessment of ABG and sampling for cortisol, insulin and glucose levels were repeated 30 min after pneumoperitonium and 60 min after extubation. The P-peak levels observed before (18.9 ± 3.8 versus 15 ± 2.2 cmH2O) and during (23.3 ± 3.8 versus 20.1 ± 2.9 cmH2O) pneumoperitoneum in Group VC were significantly higher. Postoperative partial arterial oxygen pressure (PaO2) values are higher (98 ± 12 versus 86 ± 11 mmHg) in Group PC. Arterial carbon dioxide pressure (PaCO2) values (41.8 ± 5.4 versus 36.7 ± 3.5 mmHg) during pneumoperitonium and post-operative mean cortisol and insulin levels were higher in Group VC. When compared to VCV mode, PCV mode may improve compliance during pneumoperitoneum

  8. Thermal comfort of seated occupants in rooms with personalized ventilation combined with mixing or displacement ventilation

    DEFF Research Database (Denmark)

    Forejt, L.; Melikov, Arsen Krikor; Cermak, Radim

    2004-01-01

    The performance of two personalized ventilation systems combined with mixing or displacement ventilation was studied under different conditions in regard to thermal comfort of seated occupants. The cooling performance of personalized ventilation was found to be independent of room air distribution....... Differences between the personalized air terminal devices were identified in terms of the cooling distribution over the manikin¿s body. The personalized ventilation supplying air from the front towards the face provided a more uniform cooling of the body than the personalized ventilation supplying air from...

  9. Moving horizon control and estimation of livestock ventilation systems and indoor climate

    DEFF Research Database (Denmark)

    Wu, Zhuang; Stoustrup, Jakob; Jørgensen, John Bagterp

    2008-01-01

    In this paper, a new control strategy involves exploiting actuator redundancy in a multivariable system is developed for rejecting the covariance of the fast frequency disturbances and pursuing optimum energy solution. This strategy enhances the resilience of the control system to disturbances be...

  10. Numerical simulation of a cabin ventilation subsystem in a space station oriented real-time system

    Directory of Open Access Journals (Sweden)

    Zezheng QIU

    2017-12-01

    Full Text Available An environment control and life support system (ECLSS is an important system in a space station. The ECLSS is a typical complex system, and the real-time simulation technology can help to accelerate its research process by using distributed hardware in a loop simulation system. An implicit fixed time step numerical integration method is recommended for a real-time simulation system with time-varying parameters. However, its computational efficiency is too low to satisfy the real-time data interaction, especially for the complex ECLSS system running on a PC cluster. The instability problem of an explicit method strongly limits its application in the ECLSS real-time simulation although it has a high computational efficiency. This paper proposes an improved numerical simulation method to overcome the instability problem based on the explicit Euler method. A temperature and humidity control subsystem (THCS is firstly established, and its numerical stability is analyzed by using the eigenvalue estimation theory. Furthermore, an adaptive operator is proposed to avoid the potential instability problem. The stability and accuracy of the proposed method are investigated carefully. Simulation results show that this proposed method can provide a good way for some complex time-variant systems to run their real-time simulation on a PC cluster. Keywords: Numerical integration method, Real-time simulation, Stability, THCS, Time-variant system

  11. Operating theatre ventilation systems and microbial air contamination in total joint replacement surgery: results of the GISIO-ISChIA study.

    Science.gov (United States)

    Agodi, A; Auxilia, F; Barchitta, M; Cristina, M L; D'Alessandro, D; Mura, I; Nobile, M; Pasquarella, C

    2015-07-01

    Recent studies have shown a higher rate of surgical site infections in hip prosthesis implantation using unidirectional airflow ventilation compared with turbulent ventilation. However, these studies did not measure the air microbial quality of operating theatres (OTs), and assumed it to be compliant with the recommended standards for this ventilation technique. To evaluate airborne microbial contamination in OTs during hip and knee replacement surgery, and compare the findings with values recommended for joint replacement surgery. Air samplings were performed in 28 OTs supplied with unidirectional, turbulent and mixed airflow ventilation. Samples were collected using passive sampling to determine the index of microbial air contamination (IMA). Active sampling was also performed in some of the OTs. The average number of people in the OT and the number of door openings during the sampling period were recorded. In total, 1228 elective prosthesis procedures (60.1% hip and 39.9% knee) were included in this study. Of passive samplings performed during surgical activity in unidirectional airflow ventilation OTs (U-OTs) and mixed airflow OTs (M-OTs), 58.9% and 87.6% had IMA values >2, respectively. Of samplings performed during surgical activity in turbulent airflow OTs (T-OTs) and in turbulent airflow OTs with the surgical team wearing Steri-Shield Turbo Helmets (TH-OTs), 8.6% and 60% had IMA values ≤ 2, respectively. Positive correlation was found between IMA values and the number of people in the OT and the number of door openings (P systems always provide acceptable airborne bacterial counts. Copyright © 2015 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

  12. Decreased respiratory system compliance on the sixth day of mechanical ventilation is a predictor of death in patients with established acute lung injury

    Directory of Open Access Journals (Sweden)

    Matthay Michael A

    2011-04-01

    Full Text Available Abstract Background Multiple studies have identified single variables or composite scores that help risk stratify patients at the time of acute lung injury (ALI diagnosis. However, few studies have addressed the important question of how changes in pulmonary physiologic variables might predict mortality in patients during the subacute or chronic phases of ALI. We studied pulmonary physiologic variables, including respiratory system compliance, P/F ratio and oxygenation index, in a cohort of patients with ALI who survived more than 6 days of mechanical ventilation to see if changes in these variables were predictive of death and whether they are informative about the pathophysiology of subacute ALI. Methods Ninety-three patients with ALI who were mechanically ventilated for more than 6 days were enrolled in this prospective cohort study. Patients were enrolled at two medical centers in the US, a county hospital and a large academic center. Bivariate analyses were used to identify pulmonary physiologic predictors of death during the first 6 days of mechanical ventilation. Predictors on day 1, day 6 and the changes between day 1 and day 6 were compared in a multivariate logistic regression model. Results The overall mortality was 35%. In multivariate analysis, the PaO2/FiO2 (OR 2.09, p th day of acute lung injury. In addition, a decrease in respiratory system compliance between days 1 and days 6 (OR 2.14, p Conclusions A low respiratory system compliance on day 6 or a decrease in the respiratory system compliance between the 1st and 6th day of mechanical ventilation were associated with increased mortality in multivariate analysis of this cohort of patients with ALI. We suggest that decreased respiratory system compliance may identify a subset of patients who have persistent pulmonary edema, atelectasis or the fibroproliferative sequelae of ALI and thus are less likely to survive their hospitalization.

  13. Study of Air Pollution Due to Plasma Cutting Process and Designing Local Ventilation System with Collector in Central Workshop of Mobarakeh Steel Company

    Directory of Open Access Journals (Sweden)

    Farideh Atabi

    2014-06-01

    Full Text Available Background & Objectives : Cutting leads to production of different hazardous agents such as fumes, particles, gases and vapors. In various studies, the effects of fumes, gases, and vapors on workers and environment have been proved. Meanwhile, cutting alloying plates with plasma cutting machine due to containing various alloy materials produces a lot of air pollution. Therefore, using the ventilation system to remove the mentioned pollution has always been noteworthy. Method: This study was performed on plasma cutting machine at Mobarakeh Steel Company. At first, according to ASTM the elements from alloy plates with optical emission spectrometry crm-35000-quantometery were detected, the air pollution from cutting the mentioned plates was sampled and measured using NIOSH 7300 method and according to the ACGIH:VS-72-20, VS-70-12, VS-70-11 VS-916 push-pull ventilation with bag filter collector was designed. Results: Results of sampling from pollution of cutting the alloy material, concentration of iron, lead and cadmium fumes were more than the standard limits. After calculation for push system, air flow volume of 195.163 cfm, outgoing air velocity of 5937.4 fpm and for pull system air flow volume of 12498 cfm, minimum duct velocity of 3000 fpm and velocity pressure of duct of 0.717 inwg, for fan, total pressure of 6.301 inwg, static pressure of 0.587 inwg and power of 20.65 Bhp and for collector with pulse jet cleaning system air to cloth ratio of 7 and dimensions of 6.88ft × 6.56ft × 9.84ft were obtained. Conclusion: The result of study indicated that push pull ventilation compared to other ventilation system s for plasma cutting has more efficiency and makes suitable control for pollution.

  14. Hydra effects in stable communities and their implications for system dynamics.

    Science.gov (United States)

    Cortez, Michael H; Abrams, Peter A

    2016-05-01

    A hydra effect occurs when the mean density of a species increases in response to greater mortality. We show that, in a stable multispecies system, a species exhibits a hydra effect only if maintaining that species at its equilibrium density destabilizes the system. The stability of the original system is due to the responses of the hydra-effect species to changes in the other species' densities. If that dynamical feedback is removed by fixing the density of the hydra-effect species, large changes in the community make-up (including the possibility of species extinction) can occur. This general result has several implications: (1) Hydra effects occur in a much wider variety of species and interaction webs than has previously been described, and may occur for multiple species, even in small webs; (2) conditions for hydra effects caused by predators (or diseases) often differ from those caused by other mortality factors; (3) introducing a specialist or a switching predator of a hydra-effect species often causes large changes in the community, which frequently involve extinction of other species; (4) harvest policies that attempt to maintain a constant density of a hydra-effect species may be difficult to implement, and, if successful, are likely to cause large changes in the densities of other species; and (5) trophic cascades and other indirect effects caused by predators of hydra-effect species can exhibit amplification of effects or unexpected directions of change. Although we concentrate on systems that are originally stable and models with no stage-structure or trait variation, the generality of our result suggests that similar responses to mortality will occur in many systems without these simplifying assumptions. In addition, while hydra effects are defined as responses to altered mortality, they also imply counterintuitive responses to changes in immigration and other parameters affecting population growth.

  15. Fan System Optimization Improves Ventilation and Saves Energy at a Computer Chip Manufacturer

    Energy Technology Data Exchange (ETDEWEB)

    None

    2002-01-01

    This case study describes an optimization project implemented on a fan system at Ash Grove Cement Company, which led to annual energy and maintenance savings of $16,000 and 175,000 kilowatt-hours (kWh).

  16. TECHNICAL BASIS DOCUMENT FOR VENTILATION SYSTEM FILTRATION FAILURE LEADING TO AN UNFILTERED RELEASE

    Energy Technology Data Exchange (ETDEWEB)

    KOZLOWSKI, S.D.

    2005-01-06

    This document analyzed three scenarios involving failures of HEPA filtration systems leading to releases from liquid waste tanks. The scenarios are failure due to high temperature (fire), overpressure (filter blowout), and unfiltered release due to filter failure, improper installation. etc.

  17. Experimental study of hybrid interface cooling system using air ventilation and nanofluid

    Science.gov (United States)

    Rani, M. F. H.; Razlan, Z. M.; Bakar, S. A.; Desa, H.; Wan, W. K.; Ibrahim, I.; Kamarrudin, N. S.; Bin-Abdun, Nazih A.

    2017-09-01

    The hybrid interface cooling system needs to be established to chill the battery compartment of electric car and maintained its ambient temperature inside the compartment between 25°C to 35°C. The air cooling experiment has been conducted to verify the cooling capacity, compressor displacement volume, dehumidifying value and mass flow rate of refrigerant (R-410A). At the same time, liquid cooling system is analysed theoretically by comparing the performance of two types of nanofluid, i.e., CuO + Water and Al2O3 + Water, based on the heat load generated inside the compartment. In order for the result obtained to be valid and reliable, several assumptions are considered during the experimental and theoretical analysis. Results show that the efficiency of the hybrid interface cooling system is improved as compared to the individual cooling system.

  18. Dynamic oxygen transfer measurements under operating conditions as a basis for the optimization of ventilation systems; Dynamische Sauerstoffeintragsmessungen unter Betriebsbedingungen als Grundlage zur Optimierung von Belueftungssystemen

    Energy Technology Data Exchange (ETDEWEB)

    Libra, J.A.; Biskup, M.; Wiesmann, U. [Technische Univ. Berlin (Germany). Inst. fuer Verfahrenstechnik; Sahlmann, C.; Gnirss, R. [Berliner Wasserbetriebe, Berlin (Germany)

    1999-07-01

    The largest single energy consumer at sewage treatment plants is the ventilation system of activated sludge tanks. This is why controlling and optimizing ventilation systems is the most appropriate approach to the cutting down of energy costs. The present paper reports on measurements of dynamic oxygen transfer by means of the off-gas method under operating conditions at the Berlin-Ruhleben sewage treatment plant. (orig.) [German] Der groesste Einzelenergieverbraucher auf Klaerwerken ist das Belueftungssystem von Belebungsbecken. Deshalb ist die Kontrolle und Optimierung der Belueftungssysteme der geeignete Weg zur Verringerung der Energiekosten. In diesem Beitrag wird ueber Messungen des dynamischen Sauerstoffeintrags mit der Abluft-Methode unter Betriebsbedingungen im Klaerwerk Berlin-Ruhleben berichtet. (orig.)

  19. Meta-Analysis of Data from the Submarine Ventilation Doctrine Test Program

    National Research Council Canada - National Science Library

    Hoover, J

    1998-01-01

    .... The Submarine Ventilation Doctrine Test Program was developed to address submarine-specific issues regarding the use of ventilation systems to control smoke and heat movement, maintain habitability...

  20. Randomized crossover trial of a pressure sensing visual feedback system to improve mask fitting in noninvasive ventilation.

    Science.gov (United States)

    Brill, Anne-Kathrin; Moghal, Mohammad; Morrell, Mary J; Simonds, Anita K

    2017-10-01

    A good mask fit, avoiding air leaks and pressure effects on the skin are key elements for a successful noninvasive ventilation (NIV). However, delivering practical training for NIV is challenging, and it takes time to build experience and competency. This study investigated whether a pressure sensing system with real-time visual feedback improved mask fitting. During an NIV training session, 30 healthcare professionals (14 trained in mask fitting and 16 untrained) performed two mask fittings on the same healthy volunteer in a randomized order: one using standard mask-fitting procedures and one with additional visual feedback on mask pressure on the nasal bridge. Participants were required to achieve a mask fit with low mask pressure and minimal air leak (bridge, perceived comfort of mask fit and staff- confidence were measured. Compared with standard mask fitting, a lower pressure was exerted on the nasal bridge using the feedback system (71.1 ± 17.6 mm Hg vs 63.2 ± 14.6 mm Hg, P bridge (74.5 ± 21.2 mm Hg vs 66.1 ± 17.4 mm Hg, P = 0.023 and 67 ± 12.1 mm Hg vs 60 ± 10.6 mm Hg, P = 0.002, respectively) using the feedback system and self-rated confidence increased in the untrained group. Real-time visual feedback using pressure sensing technology supported healthcare professionals during mask-fitting training, resulted in a lower pressure on the skin and better mask fit for the volunteer, with increased staff confidence. © 2017 Asian Pacific Society of Respirology.

  1. Wings as impellers: honey bees co-opt flight system to induce nest ventilation and disperse pheromones.

    Science.gov (United States)

    Peters, Jacob M; Gravish, Nick; Combes, Stacey A

    2017-06-15

    Honey bees (Apis mellifera) are remarkable fliers that regularly carry heavy loads of nectar and pollen, supported by a flight system - the wings, thorax and flight muscles - that one might assume is optimized for aerial locomotion. However, honey bees also use this system to perform other crucial tasks that are unrelated to flight. When ventilating the nest, bees grip the surface of the comb or nest entrance and fan their wings to drive airflow through the nest, and a similar wing-fanning behavior is used to disperse volatile pheromones from the Nasonov gland. In order to understand how the physical demands of these impeller-like behaviors differ from those of flight, we quantified the flapping kinematics and compared the frequency, amplitude and stroke plane angle during these non-flight behaviors with values reported for hovering honey bees. We also used a particle-based flow visualization technique to determine the direction and speed of airflow generated by a bee performing Nasonov scenting behavior. We found that ventilatory fanning behavior is kinematically distinct from both flight and scenting behavior. Both impeller-like behaviors drive flow parallel to the surface to which the bees are clinging, at typical speeds of just under 1 m s-1 We observed that the wings of fanning and scenting bees frequently contact the ground during the ventral stroke reversal, which may lead to wing wear. Finally, we observed that bees performing Nasonov scenting behavior sometimes display 'clap-and-fling' motions, in which the wings contact each other during the dorsal stroke reversal and fling apart at the start of the downstroke. We conclude that the wings and flight motor of honey bees comprise a multifunctional system, which may be subject to competing selective pressures because of its frequent use as both a propeller and an impeller. © 2017. Published by The Company of Biologists Ltd.

  2. Wii, Kinect, and Move. Heart Rate, Oxygen Consumption, Energy Expenditure, and Ventilation due to Different Physically Active Video Game Systems in College Students

    OpenAIRE

    SCHEER, KRISTA S.; SIEBRANT, SARAH M.; Brown, Gregory A.; Brandon S. Shaw; Shaw, Ina

    2014-01-01

    Nintendo Wii, Sony Playstation Move, and Microsoft XBOX Kinect are home video gaming systems that involve player movement to control on-screen game play. Numerous investigations have demonstrated that playing Wii is moderate physical activity at best, but Move and Kinect have not been as thoroughly investigated. The purpose of this study was to compare heart rate, oxygen consumption, and ventilation while playing the games Wii Boxing, Kinect Boxing, and Move Gladiatorial Combat. Heart rate, o...

  3. Use of solar electricity in near-production vehicles. [Solar-assisted air conditioning and electrical system; also ventilation of parked car

    Energy Technology Data Exchange (ETDEWEB)

    Grundmann, E.; Koenig, A. (Volkswagen AG, Research-New Technologies/ Energy Systems (DE))

    1992-01-01

    In a research project, support by the EEC, possible applications of PV power in near production passenger cars were examined. Solar ventilation of parked cars lowers the heat build up in the sun by more than 50%. Solar assisted a.c. systems can be designed for lower power input at improved performance. Supplying the electrical power for the vehicle consumers from a solar panel instead of the vehicles alternator lead to fuel economy improvements of 3 to 9%. (author).

  4. Parallel electrochemical treatment system and application for identifying acid-stable oxygen evolution electrocatalysts.

    Science.gov (United States)

    Jones, Ryan J R; Shinde, Aniketa; Guevarra, Dan; Xiang, Chengxiang; Haber, Joel A; Jin, Jian; Gregoire, John M

    2015-02-09

    Many energy technologies require electrochemical stability or preactivation of functional materials. Due to the long experiment duration required for either electrochemical preactivation or evaluation of operational stability, parallel screening is required to enable high throughput experimentation. Imposing operational electrochemical conditions to a library of materials in parallel creates several opportunities for experimental artifacts. We discuss the electrochemical engineering principles and operational parameters that mitigate artifacts in the parallel electrochemical treatment system. We also demonstrate the effects of resistive losses within the planar working electrode through a combination of finite element modeling and illustrative experiments. Operation of the parallel-plate, membrane-separated electrochemical treatment system is demonstrated by exposing a composition library of mixed-metal oxides to oxygen evolution conditions in 1 M sulfuric acid for 2 h. This application is particularly important because the electrolysis and photoelectrolysis of water are promising future energy technologies inhibited by the lack of highly active, acid-stable catalysts containing only earth abundant elements.

  5. System Design for Demand Controlled Ventilation in Multi-Family Dwellings

    DEFF Research Database (Denmark)

    Mortensen, Dorthe Kragsig; Nielsen, Toke Rammer

    2011-01-01

    exchanger should not exceed 3400 DKK per dwelling in regions with weather conditions similar to the Danish climate. A design expected to fulfil this requirement was investigated in detail with regard to its electricity consumption by evaluation of different control strategies. Systems with variable airflows...... are typically controlled by maintaining the static pressure at a fixed level at a selected point in the main duct. However, sustaining the static pressure at a fixed level at part load leads to throttling of all control components and thereby unnecessary energy consumption. Resetting the static pressure at part...... load reduces throttling and energy can be saved. A static pressure reset strategy was applied to a dwelling-specific DCV system where the airflow varied between three fixed rates. The system performance was evaluated for two diffusers. The annual electricity consumption was reduced by 20% to 30% when...

  6. Middle ear ventilation status postoperatively after translabyrinthine resection of vestibular schwannoma with mastoid obliteration and Eustachian tube occlusion: is the Eustachian tube enough to ventilate the middle ear without the mastoid air cell system?

    Science.gov (United States)

    Belyea, James; Wickens, Brandon; Bance, Manohar

    2016-08-30

    Gas pressure balance is essential for maintaining normal middle ear function. The mucosal surfaces of the middle ear, the mastoid air cell system (MACS), and the Eustachian tube (ET) play a critical role in this process; however, the extent that each of these factors contributes to overall middle ear ventilation is unknown. The objective of this study was to determine if the ET alone can maintain normal middle ear pressure without the MACS. To do this, we reviewed subjects who had their MACS completely removed with translabyrinthine (TL) surgery for vestibular schwannoma. A retrospective chart review was done to collect pre and postoperative tympanometry data from patients who underwent resection of vestibular schwannoma. Data from the operative side was compared to the non-operative side at 2 years post-op. Twenty-four patients were included in this study. Of these, 63 % achieved a type A tympanogram at 2 years post-op in the TL resection group, implying an ability to maintain middle ear pressure in the absence of a mastoid cavity. Because some had negative pressures post TL resection, the average change in pre and postoperative pressure was -37.5 daPa for the operative side and 7.8 daPa for the non-operative side. This was significantly different. The difference for change in pre and postoperative pressure and compliance between operative and non-operative side might be expected from the ET plugging during TL resection. However, more interesting are those patients in whom the ET presumably reopens, and in these subjects, despite having no mastoid compartment at all, and the space obliterated with fat, they were still able to maintain normal ventilation of the middle ear space. Our findings imply that the ET alone is adequate to ventilate at least the reduced middle ear space following TL surgery in most subjects, and perhaps in 100 % if the ET hadn't been plugged during surgery. Hence, the mastoid air cell system, even when healthy, is not needed to maintain

  7. Fungal colonization of air filters for use in heating, ventilating, and air conditioning (HVAC) systems.

    Science.gov (United States)

    Simmons, R B; Crow, S A

    1995-01-01

    New and used cellulosic air filters for HVAC systems including those treated with antimicrobials were suspended in vessels with a range of relative humidities (55-99%) and containing non-sterile potting soil which stimulates fungal growth. Most filters yielded fungi prior to suspension in the chambers but only two of 14 nontreated filters demonstrated fungal colonization following use in HVAC systems. Filters treated with antimicrobials, particularly a phosphated amine complex, demonstrated markedly less fungal colonization than nontreated filters. In comparison with nontreated cellulosic filters, fungal colonization of antimicrobial-treated cellulosic filters was selective and delayed.

  8. An Intelligent Energy Saving System for Controlling the Lighting and Ventilation of an Area

    OpenAIRE

    Kadiri Kamoru. O; Omotosho O. J

    2014-01-01

    Intelligent Energy Saving System is a control system used to control a particular environment in other to optimize the energy. It can be used to control the lighting or air conditioning of an area. An example is the library which can be well illuminated with many lamps. When people are not present at a reading place, the lighting can be made OFF and when they are present, the lighting is made ON by using a sensor to sense the environment condition example temperature, obstacle etc. All these ...

  9. Stable Polymorphisms in a Two-Locus Gene-for-Gene System.

    Science.gov (United States)

    Segarra, J

    2005-07-01

    ABSTRACT A two-locus gene-for-gene model is presented to analyze coevolutionary dynamics in interactions between host plants and their pathogens. Using both analytical and simulation approximations, we show that the behavior of the model is very simple with one locus. In the reciprocal genetic feedback version, there is a smooth outward spiral toward the boundaries. In the delayed feedback version, there is an infinite family of closed curves corresponding to different initial conditions. Both versions of the model are stabilized by the addition of recurrent mutation. Either a stable interior equilibrium or a stable limit cycle appears. But with the two-locus model, different coevolutionary outcomes are predicted according to the parameter values. For a wide range of small and medium values of virulence and resistance costs, complex fluctuations arise. The number of virulence alleles per isolate and the number of resistance alleles per plant cycle indefinitely. If the costs of both virulence and resistance are above a threshold, the final state of the coevolutionary dynamics is a stable single-resistance static polymorphism in the host and avirulence in the parasite. An equivalent threshold to maintain a disease-free host population was obtained analytically for a multilocus system. These expressions can be used to determine the number of single-resistance host genotypes that would have to be present in a mixture to prevent the spread of any virulent race of pathogen. The model demonstrates that it is preferable to use mixtures of single-resistant genotypes rather than using multiple resistance alleles in the same cultivar.

  10. Ventilator associated pneumonia or ventilator induced pneumonia.

    Science.gov (United States)

    Khan, Zahid Hussain; Ceriana, Piero; Donner, Claudio F

    2017-01-01

    Ventilator associated pneumonia currently in vogue seems to have some pitfalls as far as the nomenclature is concerned and thus it imparts an erroneous impression to the reader. As the driving force is in fact the ventilator, the phraseology should preferably be changed to ventilator induced pneumonia to convey the in depth meaning of the term thus evading the terminology currently in practice. A new and emerging paradigm dealing with all side effects of mechanical ventilation can be helpful to solve this etymological conflict.

  11. Laboratory study of subjective perceptions to low temperature heating systems with exhaust ventilation in Nordic countries

    DEFF Research Database (Denmark)

    Jin, Quan; Simone, Angela; Olesen, Bjarne W.

    2017-01-01

    Given the global trends of rising energy demand and the increasing utilization of low-grade renewable energy, low-temperature heating systems can play key roles in improving building energy efficiency while providing a comfortable indoor environment. To meet the need to retrofit existing buildings...

  12. Laboratory study of subjective perceptions to low temperature heating systems with exhaust ventilation in Nordic countries

    DEFF Research Database (Denmark)

    Jin, Quan; Simone, Angela; Olesen, Bjarne W.

    2017-01-01

    Given the global trends of rising energy demand and the increasing utilization of low-grade renewable energy, low-temperature heating systems can play key roles in improving building energy efficiency while providing a comfortable indoor environment. To meet the need to retrofit existing building...

  13. Prediction of novel stable compounds in the Mg-Si-O system under exoplanet pressures

    Science.gov (United States)

    Niu, Haiyang; Oganov, Artem R.; Chen, Xing-Qiu; Li, Dianzhong

    2015-12-01

    The Mg-Si-O system is the major Earth and rocky planet-forming system. Here, through quantum variable-composition evolutionary structure explorations, we have discovered several unexpected stable binary and ternary compounds in the Mg-Si-O system. Besides the well-known SiO2 phases, we have found two extraordinary silicon oxides, SiO3 and SiO, which become stable at pressures above 0.51 TPa and 1.89 TPa, respectively. In the Mg-O system, we have found one new compound, MgO3, which becomes stable at 0.89 TPa. We find that not only the (MgO)x·(SiO2)y compounds, but also two (MgO3)x·(SiO3)y compounds, MgSi3O12 and MgSiO6, have stability fields above 2.41 TPa and 2.95 TPa, respectively. The highly oxidized MgSi3O12 can form in deep mantles of mega-Earths with masses above 20 M⊕ (M⊕:Earth’s mass). Furthermore, the dissociation pathways of pPv-MgSiO3 are also clarified, and found to be different at low and high temperatures. The low-temperature pathway is MgSiO3 ⇒ Mg2SiO4 + MgSi2O5 ⇒ SiO2 + Mg2SiO4 ⇒ MgO + SiO2, while the high-temperature pathway is MgSiO3 ⇒ Mg2SiO4 + MgSi2O5 ⇒ MgO + MgSi2O5 ⇒ MgO + SiO2. Present results are relevant for models of the internal structure of giant exoplanets, and for understanding the high-pressure behavior of materials.

  14. RESULTS OF EXPERIMENT TO DETERMINE CORROSION RATES FOR 304L IN HB-LINE DISSOLVER VESSEL VENTILATION SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    Mickalonis, J; Kathryn Counts, K

    2008-02-22

    Radioactive material being processed as part of the DE3013 program for HB-Line will result in the presence of chlorides, and in some cases fluorides, in the dissolver. Material Science and Technology developed an experimental plan to evaluate the impact of chloride on corrosion of the dissolver vessel ventilation system. The plan set test variables from the proposed operating parameters, previous test results, and a desired maximum chloride concentration for processing. The test variables included concentrations of nitric acid, fluorides and chlorides, and the presence of a welded and stressed metal coupon. Table 1 contains expected general corrosion rates in the HB-Line vessel vent system from dissolution of 3013 contents of varying nitric acid and chloride content. These general corrosion rates were measured upstream of the condenser in the experiment's offgas system near the entrance to the dissolver. However, they could apply elsewhere in the offgas system, depending on factors not simulated in the testing, including offgas system temperatures and airflow. Localized corrosion was significant in Tests One, Two, and Three. This corrosion is significant because it will probably be the first mode of penetration of the 304L steel in several places in the system. See Table 2. For Tests One and Three, the penetration rate of localized corrosion was much higher than that for general corrosion. It was approximately four times higher in Test One and at least 45 times higher in Test Three, penetrating an entire coupon thickness of 54 mils in 186 hours or less. There was no significant difference in corrosion between welded areas and un-welded areas on coupons. There was also no significant attack on stressed portions of coupons. It is probable that the lack of corrosion was because the stressed areas were facing downwards and offered no place for condensation or deposits to form. Had deposits formed, pitting may have occurred and led to stress corrosion cracking. The

  15. SY Tank Farm ventilation isolation option risk assessment report

    Energy Technology Data Exchange (ETDEWEB)

    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.

  16. Decreased respiratory system compliance on the sixth day of mechanical ventilation is a predictor of death in patients with established acute lung injury.

    Science.gov (United States)

    Seeley, Eric J; McAuley, Daniel F; Eisner, Mark; Miletin, Michael; Zhuo, Hanjing; Matthay, Michael A; Kallet, Richard H

    2011-04-22

    Multiple studies have identified single variables or composite scores that help risk stratify patients at the time of acute lung injury (ALI) diagnosis. However, few studies have addressed the important question of how changes in pulmonary physiologic variables might predict mortality in patients during the subacute or chronic phases of ALI. We studied pulmonary physiologic variables, including respiratory system compliance, P/F ratio and oxygenation index, in a cohort of patients with ALI who survived more than 6 days of mechanical ventilation to see if changes in these variables were predictive of death and whether they are informative about the pathophysiology of subacute ALI. Ninety-three patients with ALI who were mechanically ventilated for more than 6 days were enrolled in this prospective cohort study. Patients were enrolled at two medical centers in the US, a county hospital and a large academic center. Bivariate analyses were used to identify pulmonary physiologic predictors of death during the first 6 days of mechanical ventilation. Predictors on day 1, day 6 and the changes between day 1 and day 6 were compared in a multivariate logistic regression model. The overall mortality was 35%. In multivariate analysis, the PaO2/FiO2 (OR 2.09, p lung injury. In addition, a decrease in respiratory system compliance between days 1 and days 6 (OR 2.14, p ventilation were associated with increased mortality in multivariate analysis of this cohort of patients with ALI. We suggest that decreased respiratory system compliance may identify a subset of patients who have persistent pulmonary edema, atelectasis or the fibroproliferative sequelae of ALI and thus are less likely to survive their hospitalization.

  17. The ability of hospital ventilation systems to filter Aspergillus and other fungi following a building implosion.

    Science.gov (United States)

    Srinivasan, Arjun; Beck, Christopher; Buckley, Timothy; Geyh, Allison; Bova, Greg; Merz, William; Perl, Trish M

    2002-09-01

    To assess the ability of hospital air handling systems to filter Aspergillus, other fungi, and particles following the implosion of an adjacent building; to measure the quantity and persistence of airborne fungi and particles at varying distances during a building implosion; and to determine whether manipulating air systems based on the movement of the dust cloud would be an effective strategy for managing the impact of the implosion. Air sampling study. A 976-bed teaching hospital in Baltimore, Maryland. Single-stage impactors and particle counters were placed at outdoor sites 100, 200, and 400 m from the implosion and in five locations in the hospital: two oncology floors, the human immunodeficiency virus unit, the cardiac surgical intensive care unit, and the ophthalmology unit. Air handling systems would operate normally unless the cloud approached the hospital. Wind carried the bulk of the cloud away from the hospital. Aspergillus counts rose more than tenfold at outdoor locations up to 200 m from the implosion, but did not increase at 400 m. Total fungal counts rose more than sixfold at 100 and 200 m and twofold at 400 m. Similar to Aspergillus, particle counts rose several-fold following the implosion at 100 and 200 m, but did not rise at 400 m. No increases in any fungi or particles were measured at indoor locations. Reacting to the movement of the cloud was effective, because normal operation of the hospital air handling systems was able to accommodate the modest increase in Aspergillus, other fungi, and particles generated by the implosion. Aspergillus measurements were paralleled by particle counts.

  18. Analysis of energy management for heating, ventilating and air-conditioning systems

    Directory of Open Access Journals (Sweden)

    Mohamed Elhelw

    2016-06-01

    Full Text Available In the office buildings, large energy is consumed due to poor thermal performance and low efficiencies of HVAC systems. A cooling load calculation is a basis for the design of building cooling systems. The current design methods are usually based on deterministic cooling loads, which are obtained by using design parameters. However, these parameters contain uncertainties, and they will be different from that used in the design calculation when the cooling system is put in use. The actual cooling load profile will deviate from that predicted in design. A modified bin method was used in this paper to optimize the energy efficiency ratio (EER. A design optimization method is proposed by considering uncertainties related to the cooling load calculation. Impacts caused by the uncertainties of seven factors are considered, including the outdoor weather conditions and internal heat sources. The cooling load distribution is analyzed. Comparison between the modified bin method and CLTD/SCL/CLF method is also conducted. With the distributions of their energy consumption, decision makers can select the optimal configuration based on quantified confidence. According to the economic benefits and energy efficiency ratio, using modified bin method will increase the overall energy efficiency ratio by 45.57%.

  19. Concentration Distribution in a Mixing Ventilated Room

    DEFF Research Database (Denmark)

    Jensen, Rasmus Lund; Pedersen, D. N.; Nielsen, Peter Vilhelm

    2001-01-01

    Today there is an increasing focus on the importance of a proper ventilation system to obtain good working conditions in the term of air and thermal quality to ensure high productivity. Different ventilation principles are used, e.g., mixing ventilation and displacement ventilation. In order....... Full scale experiments along with a breathing thermal manikin (BTM) have been used. The results show that the location of the sources is of great importance, just as well as temperature differences. Furthermore, the concentration in the breathing zone showed large differences throughout the room....

  20. Sleep and Mechanical Ventilation in Critical Care.

    Science.gov (United States)

    Blissitt, Patricia A

    2016-06-01

    Sleep disturbances in critically ill mechanically ventilated patients are common. Although many factors may potentially contribute to sleep loss in critical care, issues around mechanical ventilation are among the more complex. Sleep deprivation has systemic effects that may prolong the need for mechanical ventilation and length of stay in critical care and result in worse outcomes. This article provides a brief review of the physiology of sleep, physiologic changes in breathing associated with sleep, and the impact of mechanical ventilation on sleep. A summary of the issues regarding research studies to date is also included. Recommendations for the critical care nurse are provided. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. Concentration Distribution in a Mixing Ventilated Room

    DEFF Research Database (Denmark)

    Jensen, Rasmus Lund; Pedersen, D.N.; Nielsen, Peter V.

    2001-01-01

    Today there is an increasing focus on the importance of a proper ventilation system to obtain good working conditions in the term of air and thermal quality to ensure high productivity. Different ventilation principles are used, e.g., mixing ventilation and displacement ventilation. In order...... that the air is fully mixed. The objective of this work is to determine the influence of the location of a pollutant, temperature differences and whether the room is furnished or not. It is also investigated if it is sufficient to determine the mean concentration in the room to determine the personal exposure...

  2. Rich stoichiometries of stable Ca-Bi system: Structure prediction and superconductivity

    Science.gov (United States)

    Dong, Xu; Fan, Changzeng

    2015-03-01

    Using a variable-composition ab initio evolutionary algorithm implemented in the USPEX code, we have performed a systematic search for stable compounds in the Ca-Bi system at different pressures. In addition to the well-known tI12-Ca2Bi and oS12-CaBi2, a few more structures were found by our calculations, among which phase transitions were also predicted in Ca2Bi (tI12 --> oI12 --> hP6), Ca3Bi2 (hP5 --> mC20 --> aP5) and CaBi (tI2 --> tI8), as well as a new phase (Ca3Bi) with a cF4 structure. All the newly predicted structures can be both dynamically and thermodynamically stable with increasing pressure. The superconductive properties of cF4-CaBi3, tI2-CaBi and cF4-Ca3Bi were studied and the superconducting critical temperature Tc can be as high as 5.16, 2.27 and 5.25 K, respectively. Different superconductivity behaviors with pressure increasing have been observed by further investigations.

  3. Proposal for the award of a contract for the design, supply, installation and commissioning of a Heating, Ventilation and Air-Conditioning (HVAC) system for the computer room of the CERN Control Centre

    CERN Document Server

    2012-01-01

    Proposal for the award of a contract for the design, supply, installation and commissioning of a Heating, Ventilation and Air-Conditioning (HVAC) system for the computer room of the CERN Control Centre

  4. The Effects of Ventilation in Homes on Health

    DEFF Research Database (Denmark)

    Wargocki, Pawel

    2013-01-01

    and to reduce emissions. Often, especially in existing buildings, this strategy is difficult to implement, in which case exposures are controlled by providing sufficient, presumably clean, outdoor ventilation air to dilute and remove the contaminants. The present paper attempts to find out how much ventilation...... in existing homes. No data were found indicating that buildings having dedicated natural ventilation systems perform less well than the dwellings in which mechanical ventilation systems are installed. Newly installed mechanical ventilation systems were observed to improve health conditions. In homes...... Guidelines for Indoor Air Quality and improving ventilation measurements). Exposures should also be controlled using different ventilation methods for comparison. Future studies should also advance the understanding of how ventilation systems should be operated to achieve optimal performance. These data...

  5. Prospective randomized crossover study of a new closed-loop control system versus pressure support during weaning from mechanical ventilation.

    Science.gov (United States)

    Clavieras, Noémie; Wysocki, Marc; Coisel, Yannael; Galia, Fabrice; Conseil, Matthieu; Chanques, Gerald; Jung, Boris; Arnal, Jean-Michel; Matecki, Stefan; Molinari, Nicolas; Jaber, Samir

    2013-09-01

    Intellivent is a new full closed-loop controlled ventilation that automatically adjusts both ventilation and oxygenation parameters. The authors compared gas exchange and breathing pattern variability of Intellivent and pressure support ventilation (PSV). In a prospective, randomized, single-blind design crossover study, 14 patients were ventilated during the weaning phase, with Intellivent or PSV, for two periods of 24 h in a randomized order. Arterial blood gases were obtained after 1, 8, 16, and 24 h with each mode. Ventilatory parameters were recorded continuously in a breath-by-breath basis during the two study periods. The primary endpoint was oxygenation, estimated by the calculation of the difference between the PaO2/FIO2 ratio obtained after 24 h of ventilation and the PaO2/FIO2 ratio obtained at baseline in each mode. The variability in the ventilatory parameters was also evaluated by the coefficient of variation (SD to mean ratio). There were no adverse events or safety issues requiring premature interruption of both modes. The PaO2/FIO2 (mean ± SD) ratio improved significantly from 245 ± 75 at baseline to 294 ± 123 (P = 0.03) after 24 h of Intellivent. The coefficient of variation of inspiratory pressure and positive end-expiratory pressure (median [interquartile range]) were significantly higher with Intellivent, 16 [11-21] and 15 [7-23]%, compared with 6 [5-7] and 7 [5-10]% in PSV. Inspiratory pressure, positive end-expiratory pressure, and FIO2 changes were adjusted significantly more often with Intellivent compared with PSV. Compared with PSV, Intellivent during a 24-h period improved the PaO2/FIO2 ratio in parallel with more variability in the ventilatory support and more changes in ventilation settings.

  6. Patient-Ventilator Dyssynchrony

    Directory of Open Access Journals (Sweden)

    Elvira-Markela Antonogiannaki

    2017-11-01

    Full Text Available In mechanically ventilated patients, assisted mechanical ventilation (MV is employed early, following the acute phase of critical illness, in order to eliminate the detrimental effects of controlled MV, most notably the development of ventilator-induced diaphragmatic dysfunction. Nevertheless, the benefits of assisted MV are often counteracted by the development of patient-ventilator dyssynchrony. Patient-ventilator dyssynchrony occurs when either the initiation and/or termination of mechanical breath is not in time agreement with the initiation and termination of neural inspiration, respectively, or if the magnitude of mechanical assist does not respond to the patient’s respiratory demand. As patient-ventilator dyssynchrony has been associated with several adverse effects and can adversely influence patient outcome, every effort should be made to recognize and correct this occurrence at bedside. To detect patient-ventilator dyssynchronies, the physician should assess patient comfort and carefully inspect the pressure- and flow-time waveforms, available on the ventilator screen of all modern ventilators. Modern ventilators offer several modifiable settings to improve patient-ventilator interaction. New proportional modes of ventilation are also very helpful in improving patient-ventilator interaction.

  7. In-depth survey report: Evaluation of a ventilation system to control formaldehyde exposures during embalming at Cincinnati College of Mortuary Science, Cincinnati, Ohio

    Energy Technology Data Exchange (ETDEWEB)

    Gressel, M.G.

    1990-12-01

    The goal of the study was to develop and evaluate local exhaust ventilation controls which will reduce the embalmer's exposure to formaldehyde (50000). The Cincinnati College of Mortuary Science had three tables set up for conducting embalmings. Two of the tables were in a large room which serves as a laboratory for the students. The third was located in an isolation room and was used primarily for suspected infectious cases. All the embalmings conducted for the study were conducted in the isolation room and all involved noninfectious bodies. The local exhaust ventilation system developed for the mortuary consisted of 6 foot slot hoods on either side of the embalming table. Of the 32 personal samples taken, the formaldehyde concentration of five samples showed a concentration of 1 part per million. The author recommends that a local exhaust ventilation system similar to the design tested here be installed permanently in the isolation room and on the other tables in the main embalming laboratory.

  8. Effects of manual rib-cage compression versus PEEP-ZEEP maneuver on respiratory system compliance and oxygenation in patients receiving mechanical ventilation.

    Science.gov (United States)

    Santos, Flavio Renato Antunes Dos; Schneider Júnior, Luiz Carlos; Forgiarini Junior, Luiz Alberto; Veronezi, Jefferson

    2009-06-01

    Patients unable to perform breathing functions may be submitted to invasive mechanical ventilation. Chest physiotherapy acts directly on the treatment of these patients for the purpose of improving their lung function. The objective of this study was to evaluate the effects of manual rib-cage compression versus the positive end expiratory pressure-zero end expiratory pressure (PEEP-ZEEP) maneuver, on compliance of the respiratory system and oxygenation in patients under invasive mechanical ventilation. A double centric, prospective, randomized and crossover study, with patients under invasive mechanical ventilation, in controlled mode for more than 48 hours was carried out. The protocols of chest physiothe-rapy were randomly applied at an interval of 24 hours. Data of respiratory system compliance and oxygenation were collected before application of the protocols and 30 minutes after. Twelve patients completed the study. Intragroup analysis, for both techniques showed a statistically significant difference in tidal volume (p=0.002), static compliance (p=0.002) and dynamic compliance (p=0.002). In relation to oxygenation, in the group of manual rib-cage compression, peripheral oxygen saturation increased with a significant difference (p=0.011). Manual rib-cage compression and PEEP-ZEEP maneuver have positive clinical effects. In relation to oxygenation we found a favorable behavior of peripheral oxygen saturation in the group of manual rib-cage compression.

  9. Fast Stable Solvers for Sequentially Semi-Seperable Linear Systems of Equations

    Energy Technology Data Exchange (ETDEWEB)

    Chandrasekaran, S; DeWilde, P; Gu, M; Pals, T; van der Veen, A J; White, D A

    2003-01-17

    We define the class of sequentially semi-separable matrices in this paper. Essentially this is the class of matrices which have low numerical rank on their off diagonal blocks. Examples include banded matrices, semi-separable matrices, their sums as well as inverses of these sums. Fast and stable algorithms for solving linear systems of equations involving such matrices and computing Moore-Penrose inverses are presented. Supporting numerical results are also presented. In addition, fast algorithms to construct and update this matrix structure for any given matrix are presented. Finally, numerical results that show that the coefficient matrices resulting from global spectral discretizations of certain integral equations indeed have this matrix structure are given.

  10. Mechanical ventilator - infants

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/007240.htm Mechanical ventilator - infants To use the sharing features on this page, please enable JavaScript. A mechanical ventilator is a machine that assists with breathing. ...

  11. Analytical system for stable carbon isotope measurements of low molecular weight (C2-C6 hydrocarbons

    Directory of Open Access Journals (Sweden)

    T. Röckmann

    2011-06-01

    Full Text Available We present setup, testing and initial results from a new automated system for stable carbon isotope ratio measurements on C2 to C6 atmospheric hydrocarbons. The inlet system allows analysis of trace gases from air samples ranging from a few liters for urban samples and samples with high mixing ratios, to many tens of liters for samples from remote unpolluted regions with very low mixing ratios. The centerpiece of the sample preparation is the separation trap, which is used to separate CO2 and methane from the compounds of interest. The main features of the system are (i the capability to sample up to 300 l of air, (ii long term (since May 2009 operational δ13C accuracy levels in the range 0.3–0.8 ‰ (1-σ, and (iii detection limits of order 1.5–2.5 ngC (collected amount of substance for all reported compounds. The first application of this system was the analysis of 21 ambient air samples taken during 48 h in August 2009 in Utrecht, the Netherlands. Results obtained are generally in good agreement with those from similar urban ambient air studies. Short sample intervals allowed by the design of the instrument help to illustrate the complex diurnal behavior of hydrocarbons in an urban environment, where diverse sources, dynamical processes, and chemical reactions are present.

  12. Likelihood for transcriptions in a genetic regulatory system under asymmetric stable Lévy noise

    Science.gov (United States)

    Wang, Hui; Cheng, Xiujun; Duan, Jinqiao; Kurths, Jürgen; Li, Xiaofan

    2018-01-01

    This work is devoted to investigating the evolution of concentration in a genetic regulation system, when the synthesis reaction rate is under additive and multiplicative asymmetric stable Lévy fluctuations. By focusing on the impact of skewness (i.e., non-symmetry) in the probability distributions of noise, we find that via examining the mean first exit time (MFET) and the first escape probability (FEP), the asymmetric fluctuations, interacting with nonlinearity in the system, lead to peculiar likelihood for transcription. This includes, in the additive noise case, realizing higher likelihood of transcription for larger positive skewness (i.e., asymmetry) index β, causing a stochastic bifurcation at the non-Gaussianity index value α = 1 (i.e., it is a separating point or line for the likelihood for transcription), and achieving a turning point at the threshold value β≈-0.5 (i.e., beyond which the likelihood for transcription suddenly reversed for α values). The stochastic bifurcation and turning point phenomena do not occur in the symmetric noise case (β = 0). While in the multiplicative noise case, non-Gaussianity index value α = 1 is a separating point or line for both the MFET and the FEP. We also investigate the noise enhanced stability phenomenon. Additionally, we are able to specify the regions in the whole parameter space for the asymmetric noise, in which we attain desired likelihood for transcription. We have conducted a series of numerical experiments in "regulating" the likelihood of gene transcription by tuning asymmetric stable Lévy noise indexes. This work offers insights for possible ways of achieving gene regulation in experimental research.

  13. Impact of Fire Ventilation on General Ventilation in the Building

    Science.gov (United States)

    Zender-Świercz, Ewa; Telejko, Marek

    2017-10-01

    The fire of building is a threat to its users. The biggest threat is generation, during lifetime of fire, hot gases and smoke. The purpose of quick and efficient evacuation from the area covered by the fire, at first step the escape routes have to be secured from smokiness. The smoke ventilation systems are used for this purpose. The proper design and execution of smoke ventilation is important not only because of the safety, but also of the maintenance of comfort in the building at a time when there is no fire. The manuscript presents the effect of incorrectly realized smoke ventilation in the stairwell of the medium building. The analysis shows that the flaps of smoke ventilation located in the stairwell may have a significant impact on the proper functioning of mechanical ventilation in the period when there is no fire. The improperly installed or incorrect insulated components cause perturbation of air flow and they change pressure distribution in the building. The conclusion of the analysis is the need to include the entire technical equipment of the building during the design and realization of its individual elements. The impact of various installations at each other is very important, and the omission of any of them can cause disturbances in the proper work of another.

  14. Simulating People Moving in Displacement Ventilated Rooms

    DEFF Research Database (Denmark)

    Mattsson, M.; Bjørn, Erik; Sandberg, M.

    A displacement ventilation system works better the more uni-directional the air flow through the ventilated room is: from floor to ceiling. Thus, from an air quality point of view, there should be as little vertical mixing of the room air as possible. It is therefore comprehensible that physical...

  15. Advanced simulations of energy demand and indoor climate of passive ventilation systems with heat recovery and night cooling

    DEFF Research Database (Denmark)

    Hviid, Christian Anker; Svendsen, Svend

    with little energy consumption and with satisfying indoor climate. The concept is based on using passive measures like stack and wind driven ventilation, effective night cooling and low pressure loss heat recovery using two fluid coupled water-to-air heat exchangers developed at the Technical University...

  16. Bench-to-bedside review: Ventilation-induced renal injury through systemic mediator release - just theory or a causal relationship?

    NARCIS (Netherlands)

    J.-W. Kuiper (Jan-Willem); R. Vaschetto (Rosanna); F.D. Corte (Francesco); F.B. Plötz (Frans); A.B.J. Groeneveld (Johan)

    2011-01-01

    textabstractWe review the current literature on the molecular mechanisms involved in the pathogenesis of acute kidney injury induced by plasma mediators released by mechanical ventilation. A comprehensive literature search in the PubMed database was performed and articles were identified that showed

  17. Causes Of Low Efficiency Of Combined Ventilation System In Coal Mines In Resolving The Problem Of Air Leaks (Inflows) Between Levels And Surface

    Science.gov (United States)

    Popov, Valeriy; Filatov, Yuriy; Lee, Hee; Golik, Anatoliy

    2017-11-01

    The paper discusses the problem of the underground mining safety control. The long-term air intake to coal accumulations is reviewed as one of the reasons of endogenous fires during mining. The methods of combating air leaks (inflows) in order to prevent endogenous fires are analyzed. The calculations showing the discrepancy between the design calculations for the mine ventilation, disregarding a number of mining-andgeological and mining-engineering factors, and the actual conditions of mining are given. It is proved that the conversion of operating mines to combined (pressure and exhaust) ventilation system in order to reduce the endogenous fire hazard of underground mining is unreasonable due to impossibility of providing an optimal distribution of aerodynamic pressure in mines. The conversion does not exclude the entry of air into potentially hazardous zones of endogenous fires. The essence of the combined application of positive and negative control methods for the distribution of air pressure is revealed. It consists of air doors installation in easily ventilated airways and installation of pressure equalization chambers equipped with auxiliary fans near the stoppings, working sections and in parallel airways.The effectiveness of the combined application of negative and positive control methods for the air pressure distribution in order to reduce endogenous fire hazard of mining operations is proved.

  18. A Combined Radio- and Stable-Isotopic Study of a California Coastal Aquifer System

    Directory of Open Access Journals (Sweden)

    Michael Land

    2013-04-01

    Full Text Available Stable and radioactive tracers were utilized in concert to characterize geochemical processes in a complex coastal groundwater system and to provide constraints on the kinetics of rock/water interactions. Groundwater samples from wells within the Dominguez Gap region of Los Angeles County, California were analyzed for a suite of major cations (Na+, K+, Mg2+, Ca2+ and anions (Cl−, SO42−, silica, alkalinity, select trace elements (Ba, B, Sr, dissolved oxygen, stable isotopes of hydrogen (δD, oxygen (δ18O, dissolved inorganic carbon (δ13CDIC, and radioactive isotopes (3H, 222Rn and 223,224,226,228Ra. In the study area, groundwater may consist of a complex mixture of native groundwater, intruded seawater, non-native injected water, and oil-field brine water. In some wells, Cl− concentrations attained seawater-like values and in conjunction with isotopically heavier δ18O values, these tracers provide information on the extent of seawater intrusion and/or mixing with oil-field brines. Groundwater 3H above 1 tritium unit (TU was observed only in a few select wells close to the Dominguez Gap area and most other well groundwater was aged pre-1952. Based on an initial 14C value for the study site of 90 percent modern carbon (pmc, groundwater age estimates likely extend beyond 20 kyr before present and confirm deep circulation of some native groundwater through multiple aquifers. Enriched values of groundwater δ13CDIC in the absence of SO42− imply enhanced anaerobic microbial methanogenesis. While secular equilibrium was observed for 234U/238U (activity ratios ~1 in host matrices, strong isotopic fractionation in these groundwater samples can be used to obtain information of adsorption/desorption kinetics. Calculated Ra residence times are short, and the associated desorption rate constant is about three orders of magnitude slower than that of the adsorption rate constant. Combined stable- and radio-isotopic results provide unique insights

  19. Evaluation of the systemic micro- and macrovasculature in stable angina: A case-control study.

    Directory of Open Access Journals (Sweden)

    Ulf Neisius

    Full Text Available The diagnosis of stable angina involves the use of probability estimates based on clinical presentation, age, gender and cardiovascular risk factors. In view of the link between the cardiac and systemic vasculature we tested whether non-invasive measures of systemic micro- and macrovascular structure and function differentiate between individuals with flow-limiting coronary artery disease (CAD and those with normal coronary arteries (NCA.We recruited 84 patients undergoing elective coronary angiography for investigation of symptoms of stable angina. Patients were selected for either having significant CAD or NCA (n = 43/41; age, 56±7 vs 57±7 years, P = 0.309. Only microvascular endothelial function, measured using the Endo-PAT2000 device to determine reactive hyperaemia index (CAD vs. NCA; 1.9 [1.5; 2.3] vs. 2.1 [1.8; 2.4], P = 0.03 and sonographic carotid plaque score (CAD vs. NCA; 3.0 [1.5; 4.5] vs. 1.2 [0; 2.55], P<0.001 were significantly different between patients with CAD and NCA. No significant differences were detected in reflection magnitude (CAD vs. NCA; 1.7 [1.5; 1.8] % vs 1.7 [1.5; 1.9] %, P = 0.342, pulse wave velocity (CAD vs. NCA; 7.8±1.4 m/sec vs. 8.3±1.5 m/sec, P = 0.186, carotid intima-media thickness (CAD vs. NCA; 0.73±0.10 mm vs. 0.75±0.10 mm, P = 0.518 or carotid distensibility (CAD vs. NCA; 3.8±1.2 10-3/kPa vs. 3.4±0.9 10-3/kPa, P = 0.092. Also, the c-statistic of the pre-test probability based on history and traditional risk factors (c = 0.665; 95% CI, 0.540-0.789 was improved by the addition of the inverse RHI (c = 0.720; 95% CI, 0.605-0.836, carotid plaque score (c = 0.770, 95% CI, 0.659-0.881, and of both markers in combination (c = 0.801; 95% CI, 0.701-0.900.There are distinct differences in the systemic vasculature between patients with CAD and NCA that may have the potential to guide diagnostic and therapeutic decisions. Carotid artery plaque burden and microvascular function appear to be most promising in

  20. Monitoring during Mechnical Ventilation

    Directory of Open Access Journals (Sweden)

    Dean Hess

    1996-01-01

    Full Text Available Monitoring is a continuous, or nearly continuous, evaluation of the physiological function of a patient in real time to guide management decisions, including when to make therapeutic interventions and assessment of those interventions. Pulse oximeters pass two wavelengths of light through a pulsating vascular bed and determine oxygen saturation. The accuracy of pulse oximetry is about ±4%. Capnography measures carbon dioxide at the airway and displays a waveform called the capnogram. End-tidal PCO2 represents alveolar PCO2 and is determined by the ventilation-perfusion quotient. Use of end-tidal PCO2 as an indication of arterial PCO2 is often deceiving and incorrect in critically ill patients. Because there is normally very little carbon dioxide in the stomach, a useful application of capnography is the detection of esophageal intubation. Intra-arterial blood gas systems are available, but the clinical impact and cost effectiveness of these is unclear. Mixed venous oxygenation (PvO2 or SvO2 is a global indicator of tissue oxygenation and is affected by arterial oxygen content, oxygen consumption and cardiac output. Indirect calorimetry is the calculation of energy expenditure and respiratory quotient by the measurement of oxygen consumption and carbon dioxide production. A variety of mechanics can be determined in mechanically ventilated patients including resistance, compliance, auto-peak end-expiratory pressure (PEEP and work of breathing. The static pressure-volume curve can be used to identify lower and upper infection points, which can be used to determine the appropriate PEEP setting and to avoid alveolar overdistension. Although some forms of monitoring have become a standard of care during mechanical ventilation (eg, pulse oximetry, there is little evidence that use of any monitor affects patient outcome.

  1. Short Term Airing by Natural Ventilation

    DEFF Research Database (Denmark)

    Heiselberg, Per; Perino, M.

    2010-01-01

    that are currently available, buoyancy driven, single-sided natural ventilation has proved to be very effective and can provide high air change rates for temperature and Indoor Air Quality (IAQ) control. However, to promote a wider distribution of these systems an improvement in the knowledge of their working......The need to improve the energy efficiency of buildings requires new and more efficient ventilation systems. It has been demonstrated that innovative operating concepts that make use of natural ventilation seem to be more appreciated by occupants. Among the available ventilation strategies...... principles is necessary. The present study analyses and presents the results of an experimental evaluation of airing performance in terms of ventilation characteristics, IAQ and thermal comfort. It includes investigations of the consequences of opening time, opening frequency, opening area and expected...

  2. Stochastic resonance in multi-stable coupled systems driven by two driving signals

    Science.gov (United States)

    Xu, Pengfei; Jin, Yanfei

    2018-02-01

    The stochastic resonance (SR) in multi-stable coupled systems subjected to Gaussian white noises and two different driving signals is investigated in this paper. Using the adiabatic approximation and the perturbation method, the coupled systems with four-well potential are transformed into the master equations and the amplitude of the response is obtained. The signal-to-noise ratio (SNR) is calculated numerically to demonstrate the occurrence of SR. For the case of two driving signals with different amplitudes, the interwell resonance between two wells S1 and S3 emerges for strong coupling. The SR can appear in the subsystem with weaker signal amplitude or even without driving signal with the help of coupling. For the case of two driving signals with different frequencies, the effects of SR in two subsystems driven by high and low frequency signals are both weakened with an increase in coupling strength. The stochastic multi-resonance phenomenon is observed in the subsystem subjected to the low frequency signal. Moreover, an effective scheme for phase suppressing SR is proposed by using a relative phase between two driving signals.

  3. Using a Ventilation Controller to Optimize Residential Passive Ventilation For Energy and Indoor Air Quality

    Energy Technology Data Exchange (ETDEWEB)

    Turner, William [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Walker, Iain [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2014-08-01

    One way to reduce the energy impact of providing residential ventilation is to use passive and hybrid systems. However, these passive and hybrid (sometimes called mixed-mode) systems must still meet chronic and acute health standards for ventilation. This study uses a computer simulation approach to examine the energy and indoor air quality (IAQ) implications of passive and hybrid ventilation systems, in 16 California climate zones. Both uncontrolled and flow controlled passive stacks are assessed. A new hybrid ventilation system is outlined that uses an intelligent ventilation controller to minimise energy use, while ensuring chronic and acute IAQ standards are met. ASHRAE Standard 62.2-2010 – the United States standard for residential ventilation - is used as the chronic standard, and exposure limits for PM2.5, formaldehyde and NO2 are used as the acute standards.The results show that controlled passive ventilation and hybrid ventilation can be used in homes to provide equivalent IAQ to continuous mechanical ventilation, for less use of energy.

  4. Energy conservation does not cost anything. Tips for a correct handling of heating systems, ventilation, water, electricity; Energiesparen kostet nichts. Tipps fuer den richtigen Umgang mit Heizung, Lueftung, Wasser, Strom

    Energy Technology Data Exchange (ETDEWEB)

    Stockinger, Volker

    2012-07-01

    The author of the book under consideration provides valuable tips dealing with heating systems, ventilation, electricity and water. Easily understandable examples of straightforward measures with an immediate effect are explained. For example, proper ventilation and a proper utilization of water looks after the wallets and saves valuable resources. This guide was developed at the Competence Center ''Energy Efficient Buildings'' of the University of Applied Sciences in Munich (Federal Republic in Germany).

  5. 46 CFR 169.315 - Ventilation (other than machinery spaces).

    Science.gov (United States)

    2010-10-01

    ... section is satisfied, a vessel having only a natural ventilation system must satisfy the following: V/A≥1... 46 Shipping 7 2010-10-01 2010-10-01 false Ventilation (other than machinery spaces). 169.315... SCHOOL VESSELS Construction and Arrangement Hull Structure § 169.315 Ventilation (other than machinery...

  6. Attic Ventilation Guidelines to Minimize Icings at Eaves

    Science.gov (United States)

    1998-01-01

    by sizing natural, and if necessary, mechanical attic ventilation systems to maintain an attictemperature of 30F when the outside temperature is 22F...JAN 1998 2. REPORT TYPE 3. DATES COVERED - 4. TITLE AND SUBTITLE Attic Ventilation Guidelines to Minimize Icings at Eaves 5a. CONTRACT NUMBER...develop on roofs that slope to cold eaves. Ventilating the space below the snow-covered roof with outdoor aur to create a "cold" ventilated roof is

  7. Further results on saturated globally stabilizing linear state feedback control laws for single-input neutrally stable planar systems

    NARCIS (Netherlands)

    Yang, Tao; Stoorvogel, Antonie Arij; Saberi, Ali; Johansson, Karl H.

    2013-01-01

    It is known that for single-input neutrally stable planar systems, there exists a class of saturated globally stabilizing linear state feedback control laws. The goal of this paper is to characterize the dynamic behavior for such a system under arbitrary locally stabilizing linear state feedback

  8. Ceiling-mounted personalized ventilation system integrated with a secondary air distribution system--a human response study in hot and humid climate.

    Science.gov (United States)

    Yang, B; Sekhar, S C; Melikov, A K

    2010-08-01

    The benefits of thermal comfort and indoor air quality with personalized ventilation (PV) systems have been demonstrated in recent studies. One of the barriers for wide spread acceptance by architects and HVAC designers has been attributed to challenges and constraints faced in the integration of PV systems with the work station. A newly developed ceiling-mounted PV system addresses these challenges and provides a practical solution while retaining much of the apparent benefits of PV systems. Assessments of thermal environment, air movement, and air quality for ceiling-mounted PV system were performed with tropically acclimatized subjects in a Field Environmental Chamber. Thirty-two subjects performed normal office work and could choose to be exposed to four different PV airflow rates (4, 8, 12, and 16 L/s), thus offering themselves a reasonable degree of individual control. Ambient temperatures of 26 and 23.5 degrees C and PV air temperatures of 26, 23.5, and 21 degrees C were employed. The local and whole body thermal sensations were reduced when PV airflow rates were increased. Inhaled air temperature was perceived cooler and perceived air quality and air freshness improved when PV airflow rate was increased or temperature was reduced. The newly developed ceiling-mounted PV system offers a practical solution to the integration of PV air terminal devices (ATDs) in the vicinity of the workstation. By remotely locating the PV ATDs on the ceiling directly above the occupants and under their control, the conditioned outdoor air is now provided to the occupants through the downward momentum of the air. A secondary air-conditioning and air distribution system offers additional cooling in the room and maintains a higher ambient temperature, thus offering significant benefits in conserving energy. The results of this study provide designers and consultants with needed knowledge for design of PV systems.

  9. Thermal Plumes in Ventilated Rooms

    DEFF Research Database (Denmark)

    Kofoed, Peter; Nielsen, Peter V.

    The design of a displacement ventilation system involves determination of the flow rate in the thermal plumes. The flow rate in the plumes and the vertical temperature gradient influence each other, and they are influenced by many factors. This paper shows some descriptions of these effects....

  10. Thermal Plumes in Ventilated Rooms

    DEFF Research Database (Denmark)

    Kofoed, Peter; Nielsen, Peter V.

    Ventilation systems with vertical displacement flow have been used in industrial areas with extensive heat loads for many years. Hot and contaminant air is carried directly from the occupied zone towards the ceiling by hot processes and other activities which create a natural convection flow....

  11. Do new anesthesia ventilators deliver small tidal volumes accurately during volume-controlled ventilation?

    Science.gov (United States)

    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

  12. Quality control of nano-LC-MS systems using stable isotope-coded peptides.

    Science.gov (United States)

    Burkhart, Julia Maria; Premsler, Thomas; Sickmann, Albert

    2011-03-01

    In analytical sciences, there is a general need for quality control to assess whether a product or a process meets defined requirements. Especially in proteomics, which implies analysis of ten thousands of analytes within a complex mixture, quality control to validate LC-MS performance and method setup is inevitable to achieve day-to-day-, inter-system-, as well as inter-user reproducibility. Thus, results deriving from LC-MS analyses can be benchmarked and the need for system maintenance can be revealed. In particular with the advent of label-free quantification of peptides and proteins, which above all depends on highly stable and reproducible LC separations, HPLC performance has to be appropriately monitored throughout the entire analytical procedure to assure quality and validity of the obtained data. Oftentimes, proteolytic digests of standard proteins are used in this context; however, this approach implies some limitations, such as inadequate batch-to-batch reproducibility, limited (if any) dynamic range and compositional inflexibility. Here, we present an alternative strategy of nano-LC-MS/MS quality control based on a mixture of synthetic peptides covering the entire LC-gradient as well as a dynamic range of more than two orders of magnitude. Thus, (i) reproducibility of LC separation, (ii) MS performance (including limit of detection, identification and quantification), as well as (iii) overall nano-LC-MS system performance and reproducibility can be routinely monitored even in highly complex samples. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Biomarkers of systemic inflammation and depression and fatigue in moderate clinically stable COPD

    Directory of Open Access Journals (Sweden)

    Singh Dave

    2011-01-01

    Full Text Available Abstract Introduction COPD is an inflammatory disease with major co-morbidities. It has recently been suggested that depression may be the result of systemic inflammation. We aimed to explore the association between systemic inflammation and symptoms of depression and fatigue in patients with mainly moderate and clinically stable COPD using a range of inflammatory biomarkers, 2 depression and 2 fatigue scales. Method We assessed 120 patients with moderate COPD (FEV1% 52, men 62%, age 66. Depression was assessed using the BASDEC and CES-D scales. Fatigue was assessed using the Manchester COPD-fatigue scale (MCFS and the Borg scale before and after 6MWT. We measured systemic TNF-α, CRP, TNF-α-R1, TNF-α-R2 and IL-6. Results A multivariate linear model of all biomarkers showed that TNF-α only had a positive correlation with BASDEC depression score (p = 0.007. TNF-α remained positively correlated with depression (p = 0.024 after further adjusting for TNF-α-R1, TNF-α-R2, 6MWD, FEV1%, and pack-years. Even after adding the MCFS score, body mass and body composition to the model TNF-α was still associated with the BASDEC score (p = 0.044. Furthermore, patients with higher TNF-α level (> 3 pg/ml, n = 7 had higher mean CES-D depression score than the rest of the sample (p = 0.03. Borg fatigue score at baseline were weakly correlated with TNF-α and CRP, and with TNF-α only after 6MWT. Patients with higher TNF-α had more fatigue after 6MWD (p = 0.054. Conclusion This study indicates a possible association between TNF-α and two frequent and major co-morbidities in COPD; i.e., depression and fatigue.

  14. A generic system for the expression and purification of soluble and stable influenza neuraminidase.

    Directory of Open Access Journals (Sweden)

    Peter M Schmidt

    Full Text Available The influenza surface glycoprotein neuraminidase (NA is essential for the efficient spread of the virus. Antiviral drugs such as Tamiflu (oseltamivir and Relenza (zanamivir that inhibit NA enzyme activity have been shown to be effective in the treatment of influenza infections. The recent 'swine flu' pandemic and world-wide emergence of Tamiflu-resistant seasonal human influenza A(H1N1 H(274Y have highlighted the need for the ongoing development of new anti-virals, efficient production of vaccine proteins and novel diagnostic tools. Each of these goals could benefit from the production of large quantities of highly pure and stable NA. This publication describes a generic expression system for NAs in a baculovirus Expression Vector System (BEVS that is capable of expressing milligram amounts of recombinant NA. To construct NAs with increased stability, the natural influenza NA stalk was replaced by two different artificial tetramerization domains that drive the formation of catalytically active NA homotetramers: GCN4-pLI from yeast or the Tetrabrachion tetramerization domain from Staphylothermus marinus. Both recombinant NAs are secreted as FLAG-tagged proteins to allow for rapid and simple purification. The Tetrabrachion-based NA showed good solubility, increased stability and biochemical properties closer to the original viral NA than the GCN4-pLI based construct. The expressed quantities and high quality of the purified recombinant NA suggest that this expression system is capable of producing recombinant NA for a broad range of applications including high-throughput drug screening, protein crystallisation, or vaccine development.

  15. Effects of doxycycline on local and systemic inflammation in stable COPD patients, a randomized clinical trial.

    Science.gov (United States)

    Prins, Hendrik J; Daniels, Johannes M A; Lindeman, Jan H; Lutter, René; Boersma, Wim G

    2016-01-01

    Neutrophilic inflammation plays a causal role in Chronic Obstructive Pulmonary Disease (COPD). Neutrophil derived myeloperoxidase(MPO) matrix metalloproteinases(MMP's), and elastases are thought to contribute to the perpetuation of the disease. The tetracycline analogue doxycycline has been shown to inhibit neutrophil-mediated inflammation. It was thus reasoned that doxycycline may attenuate neutrophil-mediated inflammation in COPD. In this double blind randomized controlled trial the effect of a 3-week course of doxycycline on sputum and systemic inflammatory parameters was evaluated in stable COPD patients. In order to exclude inflammation by bacterial colonisation patients must have 2 negative sputum cultures in the previous year. The effect of doxycycline treatment on inflammatory markers (TNF-α, IL-1β and IL-6) and neutrophil specific markers in sputum (MPO, MMP's, and IL-8) and serum C-reactive protein was evaluated. Sputum was obtained by sputum induction with hypertonic saline. A total of 41 patients were included. Ten patients were excluded as they were not able to produce sputum at the first or second visit. Baseline characteristics were similar in the two groups. In the remaining patients doxycycline did not influence sputum MPO concentrations. Also MMP-8 and 9, IL-6 and IL-8 concentrations as well as lung function parameters were not affected by doxycycline. Systemic inflammation by means of CRP was also not influenced by doxycycline. A three week course of doxycycline did not influence MPO sputum levels nor any of the other inflammatory sputum and systemic markers. ClinicalTrials.gov; No.: NCT00857038 URL: clinicaltrials.gov. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. 46 CFR 190.15-15 - Ventilation for living spaces and quarters.

    Science.gov (United States)

    2010-10-01

    ... mechanical system unless it can be shown that a natural system will provide adequate ventilation. By a... 46 Shipping 7 2010-10-01 2010-10-01 false Ventilation for living spaces and quarters. 190.15-15... VESSELS CONSTRUCTION AND ARRANGEMENT Ventilation § 190.15-15 Ventilation for living spaces and quarters...

  17. Acute Effect of Static Stretching on Lower Limb Movement Performance by Using STABL Virtual Reality System.

    Science.gov (United States)

    Ameer, Mariam A; Muaidi, Qassim I

    2017-07-17

    The effect of acute static stretch (ASS) on the lower limb RT has been recently questioned to decrease the risk of falling and injuries in situations requiring a rapid reaction, as in the cases of balance disturbance. The main purpose of this study was to detect the effect of ASS on the lower limb RT by using virtual reality device. Two Group Control Group design. Research laboratory. The control and experimental groups were formed randomly from sixty female university students. Each participant in the experimental group was tested before and after ASS for the quadriceps, hamstrings and planter flexor muscles, and compared with the control group with warming-up exercise only. The stretching program involved warming-up in the form of circular running inside the lab for 5 minutes followed by stretching of each muscle group thrice, to the limit of discomfort of 45 s, with resting period of 15s between stretches. The measurements included the RT of the dominant lower extremity by using the dynamic stability program, STABL Virtual Reality System (Model No. DIZ 2709, Motek Medical and Force Link Merged Co., Amsterdam). There was statistically significant reduction (F = 162, P= .00) in post-test RT between the two groups, and significant decrease in RT after stretching, in the experimental group (7.5%) (P= .00). ASS of the lower limb muscles tends to decrease the lower limb RT and improve movement performance.

  18. New Stable Crystal Structures for Cu-Au and Ni-Pt Alloy Systems

    Science.gov (United States)

    Sanati, Mahdi; Wang, L. G.; Zunger, A.

    2003-10-01

    Cu-Au and Ni-Pt are among the best studied fcc alloy systems, exhibiting the famous L10 (AB) and L12 (A_3B) phases. We were wondering if a complete configurational search of the T=0 LDA total energies would reveal any unexpected phases. Total-energy calculations of ˜ 30 arbitrarily chosen structures were used to construct a generalized (momentum-space) Ising Hamiltonian containing ˜ 20 pair-interactions, ˜ 5-10 many-body terms, as well as the long-range strain term. This Hamiltonian was tested carefully as to its ability to predict the LDA energies of other structures. We searched the energies of all fcc configurations with 20 or less atoms per primitive cell ( ˜ 2,700,000 structures), found known L1_0, L12 as well as new, unsuspected structures. The new ground state structures are NiPt_7, Cu_2Au, and Cu_2Au_3. We also found a composition range in which there is quasicontinuum of stable, ordered structures made of (001) repeat units of simple structural motifs. This structural adaptivity is explained in terms of anisotropic, long-range strain energy.

  19. Adaptive support ventilation: State of the art review.

    Science.gov (United States)

    Fernández, Jaime; Miguelena, Dayra; Mulett, Hernando; Godoy, Javier; Martinón-Torres, Federico

    2013-01-01

    Mechanical ventilation is one of the most commonly applied interventions in intensive care units. Despite its life-saving role, it can be a risky procedure for the patient if not applied appropriately. To decrease risks, new ventilator modes continue to be developed in an attempt to improve patient outcomes. Advances in ventilator modes include closed-loop systems that facilitate ventilator manipulation of variables based on measured respiratory parameters. Adaptive support ventilation (ASV) is a positive pressure mode of mechanical ventilation that is closed-loop controlled, and automatically adjust based on the patient's requirements. In order to deliver safe and appropriate patient care, clinicians need to achieve a thorough understanding of this mode, including its effects on underlying respiratory mechanics. This article will discuss ASV while emphasizing appropriate ventilator settings, their advantages and disadvantages, their particular effects on oxygenation and ventilation, and the monitoring priorities for clinicians.

  20. Assessment of water sources to plant growth in rice based cropping systems by stable water isotopes

    Science.gov (United States)

    Mahindawansha, Amani; Kraft, Philipp; Racela, Heathcliff; Breuer, Lutz

    2016-04-01

    Rice is one of the most water-consuming crops in the world. Understanding water source utilization of rice will help us to improve water use efficiency (WUE) in paddy management. The objectives of our study are to evaluate the isotopic compositions of surface ponded water, soil water, irrigation water, groundwater, rain water and plant water and based on stable water isotope signatures to evaluate the contributions of various water sources to plant growth (wet rice, aerobic rice and maize) together with investigating the contribution of water from different soil horizons for plant growth in different maturity periods during wet and dry seasons. Finally we will compare the water balances and crop yields in both crops during both seasons and calculate the water use efficiencies. This will help to identify the most efficient water management systems in rice based cropping ecosystems using stable water isotopes. Soil samples are collected from 9 different depths at up to 60 cm in vegetative, reproductive and matured periods of plant growth together with stem samples. Soil and plant samples are extracted by cryogenic vacuum extraction. Root samples are collected up to 60 cm depth from 10 cm intercepts leading calculation of root length density and dry weight. Groundwater, surface water, rain water and irrigation water are sampled weekly. All water samples are analyzed for hydrogen and oxygen isotope ratios (d18O and dD) using Los Gatos Research DLT100. Rainfall records, ground water level, surface water level fluctuations and the amount of water irrigated in each field will be measured during the sampling period. The direct inference approach which is based on comparing isotopic compositions (dD and d18O) between plant stem water and soil water will be used to determine water sources taken up by plant. Multiple-source mass balance assessment can provide the estimated range of potential contributions of water from each soil depth to root water uptake of a crop. These

  1. Energy Analysis of Selected Air Distribution System of Heating, Ventilation and Air Conditioning System: A Case Study of a Pharmaceutical Company

    Directory of Open Access Journals (Sweden)

    DILEEP KUMAR

    2017-07-01

    Full Text Available The higher energy consumption causes environmental degradation along with depletion of conventional energy resources. The share of energy consumption in buildings is increasing with urbanization and that ultimately requires effective measures for energy conservation. In buildings, HVAC (Heating Ventilation and Air Conditioning systems require huge amount of energy. This paper estimates the effects of compression of duct insulation of an HVAC system onthe auxiliary power consumption and temperature of supplied air. A mathematical model is developed in EES (Engineering Equation Solver to ascertain these effects. The simulation results show that the cooling loss due to the insulation compression is about 14%. By increasing the insulation thickness from 10-40mm at selected points, the heat gain is estimated to decrease from 4.29-2.46kW. In addition to that effects of compression of thermal insulation on GHG (Greenhouse Gas emission are investigated to reduce from 4.2-2.3kg/ kW. Subsequently, the AC (Auxiliary Consumption and temperature of the supplied air decrease by 5% and 0.4oC, respectively

  2. Development of the CELVA-1D code to evaluate the safety of an air-ventilation system during postulated fire and explosion in the reprocessing plant. Contract research

    Energy Technology Data Exchange (ETDEWEB)

    Nishio, Gunji; Watanabe, Kouji [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Kouno, Kouji; Yamazaki, Noboru; Mukaide, Shigeo; Yoshioka, Itsuo

    1998-03-01

    The CELVA-1D computer code was developed to evaluate the confinement of radioactive materials during postulated fire and explosion in a cell of nuclear fuel reprocessing plants. The CELVA-1D code calculates a response of temperature, pressure, flow velocity of fluid in an air-ventilation system of the plants by one-dimensional thermofluid analysis and calculates an ability to confine radioactive aerosol particles by transport, deposition, and HEPA filtration. The mathematical models in CELVA-1D were verified by comparison of the calculation with the result of JAERI`s demonstration tests simulating hypothetical fire and explosion accidents in the cell. (author)

  3. Functionality of Ventilated Facades: Protection of Insulation

    Directory of Open Access Journals (Sweden)

    Petrichenko Mikhail

    2016-01-01

    Full Text Available This article discusses about methods of construction of the ventilated facades. The ventilated facade is not only the element of facing, it is the supporting structure. Their main objective - creation of air ventilating space between a facade and an external wall of the building. Moving of air in this gap protects a heater from destruction, interfering with a moisture congestion. In addition, the ventilated facade protect the building from aggressive influence of external environment, have a sound and thermal insulation properties. There are several problems of systems of the ventilated facades connected with an application of a heater. For more effective using it is necessary to minimize contact of a heater with environment.

  4. Development of stable Grid service at the next generation system of KEKCC

    Science.gov (United States)

    Nakamura, T.; Iwai, G.; Matsunaga, H.; Murakami, K.; Sasaki, T.; Suzuki, S.; Takase, W.

    2017-10-01

    A lot of experiments in the field of accelerator based science are actively running at High Energy Accelerator Research Organization (KEK) by using SuperKEKB and J-PARC accelerator in Japan. In these days at KEK, the computing demand from the various experiments for the data processing, analysis, and MC simulation is monotonically increasing. It is not only for the case with high-energy experiments, the computing requirement from the hadron and neutrino experiments and some projects of astro-particle physics is also rapidly increasing due to the very high precision measurement. Under this situation, several projects, Belle II, T2K, ILC and KAGRA experiments supported by KEK are going to utilize Grid computing infrastructure as the main computing resource. The Grid system and services in KEK, which is already in production, are upgraded for the further stable operation at the same time of whole scale hardware replacement of KEK Central Computer System (KEKCC). The next generation system of KEKCC starts the operation from the beginning of September 2016. The basic Grid services e.g. BDII, VOMS, LFC, CREAM computing element and StoRM storage element are made by the more robust hardware configuration. Since the raw data transfer is one of the most important tasks for the KEKCC, two redundant GridFTP servers are adapted to the StoRM service instances with 40 Gbps network bandwidth on the LHCONE routing. These are dedicated to the Belle II raw data transfer to the other sites apart from the servers for the data transfer usage of the other VOs. Additionally, we prepare the redundant configuration for the database oriented services like LFC and AMGA by using LifeKeeper. The LFC servers are made by two read/write servers and two read-only servers for the Belle II experiment, and all of them have an individual database for the purpose of load balancing. The FTS3 service is newly deployed as a service for the Belle II data distribution. The service of CVMFS stratum-0 is

  5. Comparison of automated and static pulse respiratory mechanics during supported ventilation.

    Science.gov (United States)

    Patel, Alpesh R; Taylor, Susan; Bersten, Andrew D

    2012-06-01

    To compare respiratory mechanics estimated by the (pulse) technique in spontaneously breathing patients during proportional assist ventilation (PAV) with load-adjustable gain factor (PAV+) mode with those measured using the flow-interruption technique during controlled ventilation. Observational study of 21 haemodynamically stable post-cardiac surgery patients with routine weaning from mechanical ventilation (Puritan-Bennett 840 ventilator) in the intensive care unit of a tertiary hospital. Bland-Altman and linear correlation of respiratory system compliance and inspiratory resistance estimated during PAV+ (C(pulse) and R(pulse)) with that measured during controlled mechanical ventilation (C(int) and Rint). C(pulse) overestimated C(int) (67.4 [SD, 27.7] v 51.6 [SD, 9.7] mL/cmH(2)O; P = 0.02), although the correlation between C(int) and C(pulse) was strong. Using the Bland-Altman method, the bias and limits of agreement were outside a clinically useful range. R(pulse) underestimated Rint (9.3 [SD, 3.0] v 11.5 [SD, 3.0] cmH(2)O/L/s; P = 0.02), with a weak positive correlation. Although the bias calculated by the Bland-Altman method was small, the limits of agreement were too large to be clinically useful. Based on these data, respiratory mechanics estimated from the (pulse) technique are too inaccurate to be clinically useful.

  6. New modes of assisted mechanical ventilation.

    Science.gov (United States)

    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.

  7. [Independent lung ventilation during general anaesthesia--preliminary report].

    Science.gov (United States)

    Sawulski, Sławomir; Nestorowicz, Andrzej; Sawicki, Marek; Kowalczyk, Michał; Stoń, Mirosław

    2010-01-01

    Unitaleral lung pathology presents a serious challenge for the anaesthesiologist. Conventional ventilation usually leads to over distension of the non-affected lung and hypoventilation of the affected lung. The optimal ventilatory strategy in such situations, is intubation with a double lumen tube and independent lung ventilation with two respirators. This is expensive and difficult, especially in an operating room. A novel approach to this problem is based on the use of a single ventilator with a volume splitter, which enables the independent ventilation of each lung, with the same frequency but different volumes, I:E ratios and PEEPs. We used the splitter in thirty-four patients, of both sexes, aged 19-78 years, and scheduled for elective thoracic surgery. All patients were intubated with a double lumen tube and ventilated in the supine and lateral positions with and without the splitter. When the lateral position was used, the volume delivered by the ventilator was split equally to each lung. In the lateral position, without the splitter, the distribution of gas delivered by the ventilator was unequal: the dependent lung receiving 47.4 +/- 6.8% of the total volume, and the non-dependent lung receiving 52.6 +/- 6.8%. When the splitter was used, both lungs were ventilated with equal volumes. All patients were cardiovasculary stable. A novel method of ventilation during anaesthesia is described, opening up new possibilities for thoracic anaesthesia that allows easy and atraumatic independent lung ventilation.

  8. Energy performance of a ventilation system for a block of apartments with a ground source heat pump as generation system

    Science.gov (United States)

    Lucchi, M.; Lorenzini, M.; Valdiserri, P.

    2017-01-01

    This work presents a numerical simulation of the annual performance of two different systems: a traditional one composed by a gas boiler-chiller pair and one consisting of a ground source heat pump (GSHP) both coupled to two thermal storage tanks. The systems serve a bloc of flats located in northern Italy and are assessed over a typical weather year, covering both the heating and cooling seasons. The air handling unit (AHU) coupled with the GSHP exhibits excellent characteristics in terms of temperature control, and has high performance parameters (EER and COP), which make conduction costs about 30% lower than those estimated for the traditional plant.

  9. Ventilation effectiveness : health benefits of heat recovery ventilators

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2010-08-15

    Studies have shown that the installation of a heat recovery ventilator (HRV) in homes in northern Canada could improve indoor air quality and the respiratory health of inhabitants. Low ventilation rates are common in many homes in the North because the climate is severe, homes are smaller and lack basements, and occupancies are higher, leading to unhealthy indoor air quality. Northern communities also have a high rate of respiratory infections. HRVs recover much of the energy used to ventilate, which is desirable in cold regions with high heating costs. For the study, the test sample was divided into two types of houses, notably houses with active HRVs and those with control HRVs that were installed and operated but that did not function. The study results showed that HRVs provided increased ventilation. Complaints by residents about HRV noise, discomfort, or low humidity were common but equally spread between those with active and placebo HRVs. The study showed that the system design needs to be improved to better suit the needs of Inuit families. The nature of northern housing presents installation and maintenance challenges. It is hard to retrofit HRV ducting inside small, existing houses, and building supplies arrive infrequently, so detailed planning and careful take-offs of all supplies and materials must be done well in advance of construction. In addition, contractors are hard to locate and have variable expertise, and there is little technical follow-up. Robust technical support by local contractors and housing authorities is therefore important. 2 refs.

  10. An analytical system for the measurement of stable hydrogen isotopes in ambient volatile organic compounds

    Science.gov (United States)

    Meisehen, T.; Bühler, F.; Koppmann, R.; Krebsbach, M.

    2015-10-01

    Stable isotope measurements in atmospheric volatile organic compounds (VOCs) are an excellent tool to analyse chemical and dynamical processes in the atmosphere. While up to now isotope studies of VOCs in ambient air have mainly focussed on carbon isotopes, we herein present a new measurement system to investigate hydrogen isotope ratios in atmospheric VOCs. This system, consisting of a gas chromatography pyrolysis isotope ratio mass spectrometer (GC-P-IRMS) and a pre-concentration system, was thoroughly characterised using a VOC test mixture. A precision of better than 9 ‰ (in δ 2H) is achieved for n-pentane, 2-methyl-1,3-butadiene (isoprene), n-heptane, 4-methyl-pentane-2-one (4-methyl-2-pentanone), methylbenzene (toluene), n-octane, ethylbenzene, m/p-xylene and 1,2,4-trimethylbenzene. A comparison with independent measurements via elemental analysis shows an accuracy of better than 9 ‰ for n-pentane, n-heptane, 4-methyl-2-pentanone, toluene and n-octane. Above a minimum required pre-concentrated compound mass the obtained δ 2H values are constant within the standard deviations. In addition, a remarkable influence of the pyrolysis process on the isotope ratios is found and discussed. Reliable measurements are only possible if the ceramic tube used for the pyrolysis is sufficiently conditioned, i.e. the inner surface is covered with a carbon layer. It is essential to verify this conditioning regularly and to renew it if required. Furthermore, influences of a necessary H3+ correction and the pyrolysis temperature on the isotope ratios are discussed. Finally, the applicability to measure hydrogen isotope ratios in VOCs at ambient levels is demonstrated with measurements of outside air on 5 different days in February and March 2015. The measured hydrogen isotope ratios range from -136 to -105 ‰ forn-pentane, from -86 to -63 ‰ for toluene, from -39 to -15 ‰ for ethylbenzene, from -99 to -68 ‰ for m/p-xylene and from -45 to -34 ‰ for o-xylene.

  11. Comfort parameters - Ventilation of a subway wagon

    Science.gov (United States)

    Petr, Pavlíček; Ladislav, Tříska

    2017-09-01

    Research and development of a ventilation system is being carried out as a part of project TA04030774 of the Technology Agency of the Czech Republic. Name of the project is "Research and Development of Mass-optimized Components for Rail Vehicles". Problems being solved are development and testing of a new concept for ventilation systems for public transport vehicles. The main improvements should be a reduction of the mass of the whole system, easy installation and reduction of the noise of the ventilation system. This article is focused on the comfort parameters in a subway wagon (measurement and evaluation carried out on a function sample in accordance with the regulations). The input to the project is a ventilator hybrid casing for a subway wagon, which was manufactured and tested during the Ministry of Industry and Trade project TIP FR-TI3/449.

  12. Process control migration towards LHC ventilation functionality

    CERN Document Server

    Blanc, D

    2003-01-01

    The adaptation of the ventilation systems as well as the integration of equipment to fit with the new LHC ventilation requirements lead us to consider a global re-engineering of the existing control system. This, decade old process control structure is composed of elements which are mixed between industrial and home made devices. The proposed modifications are made in order to upgrade the present control system and to provide efficient and well adapted control architecture to integrate the LHC ventilation equipment of the injection tunnels. Moreover, we need a plan for the next fifteen years of the LHC life cycle. The document is to present the situation of the present control system of the LEP ventilation process and to propose a plan for the migration of the control architecture. This is done considering the fact that elements of the present control infrastructure could no longer be supported from 2003 and major components must be removed from the CERN communication infrastructure.

  13. 46 CFR 111.15-10 - Ventilation.

    Science.gov (United States)

    2010-10-01

    .... (3) Each blower must have a non-sparking fan. (4) The power ventilation system must be interlocked... vertical; and (iv) That has no appliances, such as flame arresters, that impede free passage of air or gas...

  14. Inductively coupled plasma mass spectrometry for stable isotope metabolic tracer studies of living systems

    Energy Technology Data Exchange (ETDEWEB)

    Luong, Elise [Iowa State Univ., Ames, IA (United States)

    1999-05-10

    This dissertation focuses on the development of methods for stable isotope metabolic tracer studies in living systems using inductively coupled plasma single and dual quadrupole mass spectrometers. Sub-nanogram per gram levels of molybdenum (Mo) from human blood plasma are isolated by the use of anion exchange alumina microcolumns. Million-fold more concentrated spectral and matrix interferences such as sodium, chloride, sulfate, phosphate, etc. in the blood constituents are removed from the analyte. The recovery of Mo from the alumina column is 82 ± 5% (n = 5). Isotope dilution inductively coupled plasma mass spectrometry (ID-ICP-MS) is utilized for the quantitative ultra-trace concentration determination of Mo in bovine and human blood samples. The average Mo concentration in reference bovine serum determined by this method is 10.2 ± 0.4 ng/g, while the certified value is 11.5 ± 1.1 ng/g (95% confidence interval). The Mo concentration of one pool of human blood plasma from two healthy male donors is 0.5 ± 0.1 ng/g. The inductively coupled plasma twin quadrupole mass spectrometer (ICP-TQMS) is used to measure the carbon isotope ratio from non-volatile organic compounds and bio-organic molecules to assess the ability as an alternative analytical method to gas chromatography combustion isotope ratio mass spectrometry (GC-combustion-IRMS). Trytophan, myoglobin, and β-cyclodextrin are chosen for the study, initial observation of spectral interference of 13C+ with 12C 1H+ comes from the incomplete dissociation of myoglobin and/or β-cyclodextrin.

  15. Energy Savings Potential and Research, Development, & Demonstration Opportunities for Commercial Building Heating, Ventilation, and Air Conditioning Systems

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2011-09-01

    This report covers an assessment of 182 different heating, ventilation, and air-conditioning (HVAC) technologies for U.S. commercial buildings to identify and provide analysis on 17 priority technology options in various stages of development. The analyses include an estimation of technical energy-savings potential, description of technical maturity, description of non-energy benefits, description of current barriers for market adoption, and description of the technology’s applicability to different building or HVAC equipment types. From these technology descriptions, are suggestions for potential research, development and demonstration (RD&D) initiatives that would support further development of the priority technology options.

  16. Energy Savings Potential and Research, Development, & Demonstration Opportunities for Residential Building Heating, Ventilation, and Air Conditioning Systems

    Energy Technology Data Exchange (ETDEWEB)

    Goetzler, William [Navigant Consulting, Inc., Burlington, MA (United States); Zogg, Robert [Navigant Consulting, Inc., Burlington, MA (United States); Young, Jim [Navigant Consulting, Inc., Burlington, MA (United States); Schmidt, Justin [Navigant Consulting, Inc., Burlington, MA (United States)

    2012-10-01

    This report is an assessment of 135 different heating, ventilation, and air-conditioning (HVAC) technologies for U.S. residential buildings to identify and provide analysis on 19 priority technology options in various stages of development. The analyses include an estimation of technical energy-savings potential, descriptions of technical maturity, descriptions of non-energy benefits, descriptions of current barriers for market adoption, and descriptions of the technology's applicability to different building or HVAC equipment types. From these technology descriptions, are suggestions for potential research, development and demonstration (RD&D) initiatives that would support further development of the priority technology options.

  17. Hygiene guideline for the planning, installation, and operation of ventilation and air-conditioning systems in health-care settings - Guideline of the German Society for Hospital Hygiene (DGKH).

    Science.gov (United States)

    Külpmann, Rüdiger; Christiansen, Bärbel; Kramer, Axel; Lüderitz, Peter; Pitten, Frank-Albert; Wille, Frank; Zastrow, Klaus-Dieter; Lemm, Friederike; Sommer, Regina; Halabi, Milo

    2016-01-01

    Since the publication of the first "Hospital Hygiene Guideline for the implementation and operation of air conditioning systems (HVAC systems) in hospitals" (http://www.krankenhaushygiene.de/informationen/fachinformationen/leitlinien/12) in 2002, it was necessary due to the increase in knowledge, new regulations, improved air-conditioning systems and advanced test methods to revise the guideline. Based on the description of the basic features of ventilation concepts, its hygienic test and the usage-based requirements for ventilation, the DGKH section "Ventilation and air conditioning technology" attempts to provide answers for the major air quality issues in the planning, design and the hygienically safe operation of HVAC systems in rooms of health care.

  18. CO{sub 2}-controlled ventilation systems in schools - Energy savings potential; CO{sub 2}-gesteuerte Lueftungen in Schulhaeusern - Energieeinsparungen durch CO{sub 2}-gesteuerte Lueftungen. Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Haessig, W. [Haessig Sustech GmbH, Uster (Switzerland); Primas, A.; Karlstroem, P.; Leonarz, M.; Marti, M. [Basler und Hofmann Ingenieure und Planer AG, Zuerich (Switzerland)

    2008-03-15

    This illustrated final report for the Swiss Federal Office of Energy (SFOE) takes a look at the results of a project concerning the optimisation of ventilation systems in classrooms. The report presents and discusses the results of analyses made on ten classrooms in three schools - a primary school, a high school and a university of applied sciences. Some of the classrooms are equipped with ventilation systems, others are not. In particular, measurements were made on the carbon dioxide levels encountered in the classrooms. The results of the measurements made are discussed. The authors confirm that those classrooms equipped with ventilation systems can provide optimal learning conditions at minimal energy consumption. As occupancy varies strongly, CO{sub 2} based control systems are important. Finally, strategies for improving the situation in classrooms are quoted and recommendations for further action are made.

  19. 46 CFR 72.15-20 - Ventilation for crew quarters and passenger spaces.

    Science.gov (United States)

    2010-10-01

    ... shown that a natural system will provide adequate ventilation. However, vessels which trade regularly in... 46 Shipping 3 2010-10-01 2010-10-01 false Ventilation for crew quarters and passenger spaces. 72... VESSELS CONSTRUCTION AND ARRANGEMENT Ventilation § 72.15-20 Ventilation for crew quarters and passenger...

  20. 46 CFR 92.15-15 - Ventilation for crew quarters and, where provided, passenger spaces.

    Science.gov (United States)

    2010-10-01

    ..., unless it can be shown that a natural system will provide adequate ventilation. However, vessels which... 46 Shipping 4 2010-10-01 2010-10-01 false Ventilation for crew quarters and, where provided...) CARGO AND MISCELLANEOUS VESSELS CONSTRUCTION AND ARRANGEMENT Ventilation § 92.15-15 Ventilation for crew...