Cabin air quality: indoor pollutants and climate during intercontinental flights with and without tobacco smoking.

PubMed

Lindgren, T; Norbäck, D

2002-12-01

The aim was to determine cabin air quality and in-flight exposure for cabin attendants of specific pollutants during intercontinental flights. Measurements of air humidity, temperature, carbon dioxide (CO2), respirable particles, ozone (O3), nitrogen dioxide (NO2) and formaldehyde were performed during 26 intercontinental flights with Boeing 767-300 with and without tobacco smoking onboard. The mean temperature in cabin was 22.2 degrees C (range 17.4-26.8 degrees C), and mean relative air humidity was 6% (range 1-27%). The CO2 concentration during cruises was below the recommended limit of 1000 ppm during 96% of measured time. Mean indoor concentration of NO2 and O3, were 14.1 and 19.2 micrograms/m3, with maximum values of 37 and 66 micrograms/m3, respectively. The concentration of formaldehyde was below the detection limit (< 5 micrograms/m3), in most samples (77%), and the maximum value was 15 micrograms/m3. The mean concentration of respirable particles in the rear part of the aircraft (AFT galley area) was much higher (49 micrograms/m3) during smoking as compared with non-smoking conditions (3 micrograms/m3) (P < 0.001), with maximum values of 253 and 7 micrograms/m3. In conclusion, air humidity is very low on intercontinental flights, and the large variation of temperature shows a need for better temperature control. Tobacco smoking onboard leads to a significant pollution of respirable particles, particularly in the rear part of the cabin. The result supports the view that despite the high air exchange rate and efficient air filtration, smoking in commercial aircraft leads to a significant pollution and should be prohibited.

Dropwise condensation dynamics in humid air

NASA Astrophysics Data System (ADS)

Castillo Chacon, Julian Eduardo

Dropwise condensation of atmospheric water vapor is important in multiple practical engineering applications. The roles of environmental factors and surface morphology/chemistry on the condensation dynamics need to be better understood to enable efficient water-harvesting, dehumidication, and other psychrometric processes. Systems and surfaces that promote faster condensation rates and self-shedding of condensate droplets could lead to improved mass transfer rates and higher water yields in harvesting applications. The thesis presents the design and construction of an experimental facility that allows visualization of the condensation process as a function of relative humidity. Dropwise condensation experiments are performed on a vertically oriented, hydrophobic surface at a controlled relative humidity and surface subcooling temperature. The distribution and growth of water droplets are monitored across the surface at different relative humidities (45%, 50%, 55%, and 70%) at a constant surface subcooling temperature of 15 °C below the ambient temperature. The droplet growth dynamics exhibits a strong dependency on relative humidity in the early stages during which there is a large population of small droplets on the surface and single droplet growth dominates over coalescence effects. At later stages, the dynamics of droplet growth is insensitive to relative humidity due to the dominance of coalescence effects. The overall volumetric rate of condensation on the surface is also assessed as a function of time and ambient relative humidity. Low relative humidity conditions not only slow the absolute rate of condensation, but also prolong an initial transient regime over which the condensation rate remains significantly below the steady-state value. The current state-of-the-art in dropwise condensation research indicates the need for systematic experimental investigations as a function of relative humidity. The improved understanding of the relative humidity effects on the growth of single and distributed droplets offered in this thesis can improve the prediction of heat and mass transfer during dropwise condensation of humid air under differing environmental conditions. This knowledge can be used to engineer condenser systems and surfaces that are adapted for local ambient relative humidity and temperature conditions.

Automation of closed environments in space for human comfort and safety

NASA Technical Reports Server (NTRS)

1990-01-01

The Environmental Control and Life Support System (ECLSS) for the Space Station Freedom and future colonization of the Moon and Mars presents new challenges for present technologies. Current plans call for a crew of 8 to live in a safe, shirt-sleeve environment for 90 days without ground support. Because of these requirements, all life support systems must be self-sufficient and reliable. The ECLSS is composed of six subsystems. The temperature and humidity control (THC) subsystem maintains the cabin temperature and humidity at a comfortable level. The atmosphere control and supply (ACS) subsystem insures proper cabin pressure and partial pressures of oxygen and nitrogen. To protect the space station from fire damage, the fire detection and suppression (FDS) subsystem provides fire sensing alarms and extinguishers. The waste management (WM) subsystem compacts solid wastes for return to Earth, and collects urine for water recovery. Because it is impractical, if not impossible, to supply the station with enough fresh air and water for the duration of the space station's extended mission, these elements are recycled. The atmosphere revitalization (AR) subsystem removes CO2 and other dangerous contaminants from the air. The water recovery and management (WRM) subsystem collects and filters condensate from the cabin to replenish potable water supplies, and processes urine and other waste waters to replenish hygiene water supplies. These subsystems are not fully automated at this time. Furthermore, the control of these subsystems is not presently integrated; they are largely independent of one another. A fully integrated and automated ECLSS would increase astronauts' productivity and contribute to their safety and comfort. The Kansas State University Advanced Design Team is in the process of researching and designing controls for the automation of the ECLSS for Space Station Freedom and beyond. The approach chosen to solve this problem is to divide the design into three phases. The first phase is to research the ECLSS as a whole system and then concentrate efforts on the automation of a single subsystem. The AR subsystem was chosen for our focus. During the second phase, the system control process will then be applied to the AR subsystem.

Aircraft cabin air quality: an overview [correction of overvier].

PubMed

Rayman, R B

2001-03-01

In recent years, there have been increasing complaints from cockpit crew, cabin crew, and passengers that the cabin air quality of commercial aircraft is deficient. A myriad of complaints including headache, fatigue, fever, and respiratory difficulties among many others have been registered, particularly by flight attendants on long haul routes. There is also much concern today regarding the transmission of contagious disease inflight, particularly tuberculosis. The unanswered question is whether these complaints are really due to poor cabin air quality or to other factors inherent inflight such as lowered barometric pressure, hypoxia, low humidity, circadian dysynchrony, work/rest cycles, vibration etc. This paper will review some aspects relevant to cabin air quality such as carbon dioxide (CO2), carbon monoxide (CO), ozone (O3), particulates, and microorganisms as well as the cabin ventilation system to discern if there is a possible cause and effect of illness contracted inflight. The paper will conclude with recommendations on how the issue of cabin air quality may be resolved.

Desiccant humidity control system

NASA Technical Reports Server (NTRS)

Amazeen, J. (Editor)

1973-01-01

A regenerable sorbent system was investigated for controlling the humidity and carbon dioxide concentration of the space shuttle cabin atmosphere. The sorbents considered for water and carbon dioxide removal were silica gel and molecular sieves. Bed optimization and preliminary system design are discussed along with system optimization studies and weight penalites.

One-man electrochemical air revitalization system evaluation

NASA Technical Reports Server (NTRS)

Schbert, F. H.; Marshall, R. D.; Hallick, T. M.; Woods, R. R.

1976-01-01

A program to evaluate the performance of a one man capacity, self contained electrochemical air revitalization system was successfully completed. The technology readiness of this concept was demonstrated by characterizing the performance of this one man system over wide ranges in cabin atmospheric conditions. The electrochemical air revitalization system consists of a water vapor electrolysis module to generate oxygen from water vapor in the cabin air, and an electrochemical depolarized carbon dioxide concentrator module to remove carbon dioxide from the cabin air. A control/monitor instrumentation package that uses the electrochemical depolarized concentrator module power generated to partially offset the water vapor electrolysis module power requirements and various structural fluid routing components are also part of the system. The system was designed to meet the one man metabolic oxygen generation and carbon dioxide removal requirements, thereby controlling cabin partial pressure of oxygen at 22 kN/sq m and cabin pressure of carbon dioxide at 400 N/sq m over a wide range in cabin air relative humidity conditions.

Influence of iodine on the treatment of spacecraft humidity condensate to produce potable water

NASA Technical Reports Server (NTRS)

Symons, James M.; Muckle, Susan V.

1990-01-01

Several compounds in the ersatz humidity condensate do react with iodine to form iodine-substituted organic compounds (TOI), most notably phenol, acetaldehyde, ethanol, and sodium formate. Iodination of the ersatz humidity condensate produced 3.0 to 3.5 mg/L of TOI within 24 hours. The TOI that was produced by the passage of the ersatz humidity condensate through the first iodinated resin (IR) in the adsorption system was removed by the granular activated carbon that followed. TOI detected in the final effluent was formed by the reaction of the non-adsorbable condensate compounds with the final IR in the treatment series. The activated carbon bed series in the adsorption system performed poorly in its removal of TOC. The rapid breakthrough of TOC was not surprising, as the ersatz humidity condensate contained several highly soluble organic compounds, alcohols and organic acids.

ORION Environmental Control and Life Support Systems Suit Loop and Pressure Control Analysis

NASA Technical Reports Server (NTRS)

Eckhardt, Brad; Conger, Bruce; Stambaugh, Imelda C.

2015-01-01

Under NASA's ORION Multi-Purpose Crew Vehicle (MPCV) Environmental Control and Life Support System (ECLSS) Project at Johnson Space Center's (JSC), the Crew and Thermal Systems Division has developed performance models of the air system using Thermal Desktop/FloCAD. The Thermal Desktop model includes an Air Revitalization System (ARS Loop), a Suit Loop, a Cabin Loop, and Pressure Control System (PCS) for supplying make-up gas (N2 and O2) to the Cabin and Suit Loop. The ARS and PCS are designed to maintain air quality at acceptable O2, CO2 and humidity levels as well as internal pressures in the vehicle Cabin and during suited operations. This effort required development of a suite of Thermal Desktop Orion ECLSS models to address the need for various simulation capabilities regarding ECLSS performance. An initial highly detailed model of the ARS Loop was developed in order to simulate rapid pressure transients (water hammer effects) within the ARS Loop caused by events such as cycling of the Pressurized Swing Adsorption (PSA) Beds and required high temporal resolution (small time steps) in the model during simulation. A second ECLSS model was developed to simulate events which occur over longer periods of time (over 30 minutes) where O2, CO2 and humidity levels, as well as internal pressures needed to be monitored in the cabin and for suited operations. Stand-alone models of the PCS and the Negative Pressure relief Valve (NPRV) were developed to study thermal effects within the PCS during emergency scenarios (Cabin Leak) and cabin pressurization during vehicle re-entry into Earth's atmosphere. Results from the Orion ECLSS models were used during Orion Delta-PDR (July, 2014) to address Key Design Requirements (KDR's) for Suit Loop operations for multiple mission scenarios.

The shuttle orbiter cabin atmospheric revitalization systems

NASA Technical Reports Server (NTRS)

Ward, C. F.; Owens, W. L.

1975-01-01

The Orbiter Atmospheric Revitalization Subsystem (ARS) and Pressure Control Subsystem (ARPCS) are designed to provide the flight crew and passengers with a pressurized environment that is both life-supporting and within crew comfort limitations. The ARPCS is a two-gas (oxygen-nitrogen) system that obtains oxygen from the Power Reactant Supply and Distribution (PRSD) subsystem and nitrogen from the nitrogen storage tanks. The ARS includes the water coolant loop; cabin CO2, odor, humidity and temperature control; and avionics cooling. Baseline ARPCS and ARS changes since 1973 include removal of the sublimator from the water coolant loop, an increase in flowrates to accommodate increased loads, elimination of the avionics bay isolation from the cabin, a decision to have an inert vehicle during ferry flight, elimination of coldwall tubing around windows and hatches, and deletion of the cabin heater.

Effects of Cabin Upsets on Adsorption Columns for Air Revitalization

NASA Technical Reports Server (NTRS)

LeVan, M. Douglas

1999-01-01

The National Aeronautics and Space Administration (NASA) utilizes adsorption technology as part of contaminant removal systems designed for long term missions. A variety of trace contaminants can be effectively removed from gas streams by adsorption onto activated carbon. An activated carbon adsorption column meets NASA's requirements of a lightweight and efficient means of controlling trace contaminant levels aboard spacecraft and space stations. The activated carbon bed is part of the Trace Contaminant Control System (TCCS) which is utilized to purify the cabin atmosphere. TCCS designs oversize the adsorption columns to account for irregular fluctuations in cabin atmospheric conditions. Variations in the cabin atmosphere include changes in contaminant concentrations, temperature, and relative humidity. Excessively large deviations from typical conditions can result from unusual crew activity, equipment malfunctions, or even fires. The research carried out under this award focussed in detail on the effects of cabin upsets on the performance of activated carbon adsorption columns. Both experiments and modeling were performed with an emphasis on the roll of a change in relative humidity on adsorption of trace contaminants. A flow through fixed-bed apparatus was constructed at the NASA Ames Research Center, and experiments were performed there by W. Scot Appel under the direction of Dr. John E. Finn. Modeling work was performed at the University of Virginia and at Vanderbilt University by W. Scot Appel under the direction of M. Douglas LeVan. All three participants collaborated in all of the various phases of the research. The most comprehensive document describing the research is the Ph.D. dissertation of W. Scot Appel. Results have been published in several papers and presented in talks at technical conferences. All documents have been transmitted to Dr. John E. Finn.

Air quality and ocular discomfort aboard commercial aircraft.

PubMed

Backman, H; Haghighat, F

2000-10-01

Aircraft cabin air quality has been a subject of recent public health interest. Aircraft environments are designed according to standards to ensure the comfort and well-being of the occupants. The upper and lower limits of humidity set by ASHRAE standards are based on the maintenance of acceptable thermal conditions established solely on comfort considerations, including thermal sensation, skin wetness, skin dryness, dry eyes and ocular discomfort. The purpose of this study is to investigate the influence of air (carbon dioxide level, relative humidity, and temperature) aboard commercial aircraft on ocular discomfort and dry eye of aircraft personnel and passengers. Measurements of indoor air quality were performed in 15 different aircraft at different times and altitudes. Forty-two measurements of carbon dioxide, temperature, and humidity were performed with portable air samplers every 5 minutes. Passenger loads did not exceed 137 passengers. Thermal comfort rarely met ASHRAE standards. Low humidity levels and high carbon dioxide levels were found on the Airbus 320. The DC-9 had the highest humidity level and the Boeing-767 had the lowest carbon dioxide level. Air quality was poorest on the Airbus 320 aircraft. This poor level of air quality may cause intolerance to contact lenses, dry eyes, and may be a health hazard to both passengers and crew members. Improved ventilation and aircraft cabin micro-environments need to be made for the health and comfort of the occupants.

Adsorption and Processes in Spacecraft Environmental Control and Life Support Systems

NASA Technical Reports Server (NTRS)

Dall-Bauman, Liese; Finn, John E.; Kliss, Mark (Technical Monitor)

1997-01-01

The environmental control and life support system on a spacecraft must maintain a safe and comfortable environment in which the crew can live and work. The system's functions include supplying the crew with oxygen and water, as well as removing carbon dioxide, water vapor, and trace contaminants from cabin air. Although open-loop systems have been used in the past, logistics and safety factors of current and future missions in space make near-complete recycling of the cabin's air and water desirable. The recycling process may include separation and reduction of carbon dioxide, removal of trace gas-phase contaminants, recovery and purification of humidity condensate, purification and polishing of wastewater streams, and other processes. Several of these operations can be performed totally or in part by adsorption processes. Adsorption processes are frequently good candidates for separation and purification in space by virtue of such characteristics as gravity independence, high reliability, relatively high energy efficiency, design flexibility, technological maturity, and regenerability. For these reasons, adsorption has historically played a key role in life support on U.S. and Russian piloted spacecraft. This article focuses on three current spacecraft life support applications that often use adsorption technology: carbon dioxide separation from cabin air, gas-phase trace contaminant control, and potable water recovery from waste streams. In each application, adsorption technology has been selected for use on the International Space Station. The requirements, science, and hardware for each application are discussed. Eventually, human space exploration may lead to construction of planetary habitats. These habitats may have additional applications, such as control of greenhouse gas composition and purification of hydroponic solutions, and may have different requirements and resources available to them, such as gases present in the planetary atmosphere. Adsorption separation and purification processes may continue to fulfill environmental control and life support needs well into the future.

Adsorption Processes in Spacecraft Environmental Control and Life Support Systems

NASA Technical Reports Server (NTRS)

Bauman, Liese Dall; Finn, John E.; Kliss, Mark (Technical Monitor)

1998-01-01

The environmental control and life support system on a spacecraft must maintain a safe and comfortable environment in which the crew can live and work. The system's functions include supplying the crew with oxygen and water as well as removing carbon dioxide, water vapor, and trace contaminants from cabin air. Although open-loop systems have been used in the past, logistics and safety factors of current and future missions in space make near-complete recycling of the cabin's air and water imperative. The recycling process may include separation and reduction of carbon dioxide, removal of trace gas-phase contaminants, recovery and purification of humidity condensate, purification and polishing of wastewater streams, and other processes. Several of these operations can be performed totally or in part by adsorption processes. These processes are frequently good candidates to perform separations and purifications in space due to their gravity independence, high reliability, relatively high energy efficiency, design flexibility, technological maturity, and regenerability. For these reasons, adsorption has historically played a key role in life support on U.S. and Russian piloted spacecraft. This article focuses on three current spacecraft life support applications that often use adsorption technology: gas-phase trace contaminant control, carbon dioxide removal from cabin air, and potable water recovery from waste streams. In each application, adsorption technology has been selected for use on the International Space Station. The requirements, science, and hardware for each of these applications are discussed. Eventually, human space exploration may lead to construction of planetary habitats. These habitats may provide additional opportunities for use of adsorption processes, such as control of greenhouse gas composition, and may have different requirements and resources available to them, such as gases present in the planetary atmosphere. Adsorption separation and purification processes can be expected to continue to fulfill environmental control and life support needs on future missions.

Chemistry and kinetics of I2 loss in urine distillate and humidity condensate

NASA Technical Reports Server (NTRS)

Atwater, James E.; Wheeler, Richard R., Jr.; Olivadoti, J. T.; Sauer, Richard L.

1992-01-01

Time-resolved molecular absorption spectrophotometry of iodinated ersatz humidity condensates and iodinated ersatz urine distillates across the UV and visible spectral regions are used to investigate the chemistry and kinetics of I2 loss in urine distillate and humidity condensate. Single contaminant systems at equivalent concentrations are also employed to study rates of iodine. Pseudo-first order rate constants are identified for ersatz contaminant model mixtures and for individual reactive constituents. The second order bimolecular reaction of elemental iodine with formic acid, producing carbon dioxide and iodine anion, is identified as the primary mechanism underlying the decay of residual I2 in ersatz humidity concentrate.

Skin surface hydration decreases rapidly during long distance flights.

PubMed

Guéhenneux, Sabine; Gardinier, Sophie; Morizot, Frederique; Le Fur, Isabelle; Tschachler, Erwin

2012-05-01

Dehydration of the stratum corneum leads to sensations and symptoms of 'dry skin' such as skin tightness and itchiness. As these complaints are frequently experienced by airline travellers, the aim of this study was to investigate the changes in skin surface hydration during long distance flights. The study was performed on four healthy Caucasian, and on four Japanese women aged 29-39 years, travelling on long distance flights. They had stopped using skin care products at least 12 h before, and did not apply them during the flights. The air temperature and relative humidity inside the cabin, as well as skin capacitance of the face and forearm of participants, were registered at several time points before and during the flights. Relative humidity of the aircraft cabin dropped to levels below 10% within 2 h after take-off and stayed at this value throughout the flight. Skin capacitance decreased rapidly on both the face and forearms with most pronounced changes on the cheeks where it decreased by up to 37%. Our results demonstrate that during long distance flights, the aircraft cabin environment leads to a rapid decrease in stratum corneum hydration, an alteration, which probably accounts for the discomfort experienced by long distance aircraft travellers. © 2011 John Wiley & Sons A/S.

Geographical and temporal differences in electric vehicle range due to cabin conditioning energy consumption

NASA Astrophysics Data System (ADS)

Kambly, Kiran; Bradley, Thomas H.

2015-02-01

Electric vehicles (EVs) are vehicles that are propelled by electric motors powered by rechargeable battery. They are generally asserted to have GHG emissions, driveability and life cycle cost benefits over conventional vehicles. Despite this, EVs face significant challenges due to their limited on-board energy storage capacity. In addition to providing energy for traction, the energy storage device operates HVAC systems for cabin conditioning. This results in reduced driving range. The factors such as local ambient temperature, local solar radiation, local humidity, duration and thermal soak have been identified to affect the cabin conditions. In this paper, the development of a detailed system-level approach to HVAC energy consumption in EVs as a function of transient environmental parameters is described. The resulting vehicle thermal comfort model is used to address several questions such as 1) How does day to day environmental conditions affect EV range? 2) How does frequency of EV range change geographically? 3) How does trip start time affect EV range? 4) Under what conditions does cabin preconditioning assist in increasing the EV range? 5) What percentage increase in EV range can be expected due to cabin preconditioning at a given location?

Simulator with integrated HW and SW for prediction of thermal comfort to provide feedback to the climate control system

NASA Astrophysics Data System (ADS)

Pokorný, Jan; Kopečková, Barbora; Fišer, Jan; JÍcha, Miroslav

2018-06-01

The aim of the paper is to assemble a simulator for evaluation of thermal comfort in car cabins in order to give a feedback to the HVAC (heating, ventilation and air conditioning) system. The HW (hardware) part of simulator is formed by thermal manikin Newton and RH (relative humidity), velocity and temperature probes. The SW (software) part consists of the Thermal Comfort Analyser (using ISO 14505-2) and Virtual Testing Stand of Car Cabin defining the heat loads of car cabin. Simulator can provide recommendation for the climate control how to improve thermal comfort in cabin by distribution and directing of air flow, and also by amount of ventilation power to keep optimal temperature inside a cabin. The methods of evaluation of thermal comfort were verified by tests with 10 test subjects for summer (summer clothing, ambient air temperature 30 °C, HVAC setup: +24 °C auto) and winter conditions (winter clothing, ambient air temperature -5 °C, HVAC setup: +18 °C auto). The tests confirmed the validity of the thermal comfort evaluation using the thermal manikin and ISO 14505-2.

Space Station Water Quality

NASA Technical Reports Server (NTRS)

Willis, Charles E. (Editor)

1987-01-01

The manned Space Station will exist as an isolated system for periods of up to 90 days. During this period, safe drinking water and breathable air must be provided for an eight member crew. Because of the large mass involved, it is not practical to consider supplying the Space Station with water from Earth. Therefore, it is necessary to depend upon recycled water to meet both the human and nonhuman water needs on the station. Sources of water that will be recycled include hygiene water, urine, and cabin humidity condensate. A certain amount of fresh water can be produced by CO2 reduction process. Additional fresh water will be introduced into the total pool by way of food, because of the free water contained in food and the water liberated by metabolic oxidation of the food. A panel of scientists and engineers with extensive experience in the various aspects of wastewater reuse was assembled for a 2 day workshop at NASA-Johnson. The panel included individuals with expertise in toxicology, chemistry, microbiology, and sanitary engineering. A review of Space Station water reclamation systems was provided.

Numerical analysis of heat and mass transfer for water recovery in an evaporative cooling tower

NASA Astrophysics Data System (ADS)

Lee, Hyunsub; Son, Gihun

2017-11-01

Numerical analysis is performed for water recovery in an evaporative cooling tower using a condensing heat exchanger, which consists of a humid air channel and an ambient dry air channel. The humid air including water vapor produced in an evaporative cooling tower is cooled by the ambient dry air so that the water vapor is condensed and recovered to the liquid water. The conservation equations of mass, momentum, energy and vapor concentration in each fluid region and the energy equation in a solid region are simultaneously solved with the heat and mass transfer boundary conditions coupled to the effect of condensation on the channel surface of humid air. The present computation demonstrates the condensed water film distribution on the humid air channel, which is caused by the vapor mass transfer between the humid air and the colder water film surface, which is coupled to the indirect heat exchange with the ambient air. Computations are carried out to predict water recovery rate in parallel, counter and cross-flow type heat exchangers. The effects of air flow rate and channel interval on the water recovery rate are quantified.

User's manual for a computer program for the emulation/simulation of a space station Environmental Control and Life Support System (ESCM)

NASA Technical Reports Server (NTRS)

Yanosy, James L.

1988-01-01

This manual describes how to use the Emulation Simulation Computer Model (ESCM). Based on G189A, ESCM computes the transient performance of a Space Station atmospheric revitalization subsystem (ARS) with CO2 removal provided by a solid amine water desorbed subsystem called SAWD. Many performance parameters are computed some of which are cabin CO2 partial pressure, relative humidity, temperature, O2 partial pressure, and dew point. The program allows the user to simulate various possible combinations of man loading, metabolic profiles, cabin volumes and certain hypothesized failures that could occur.

Cabin fuselage structural design with engine installation and control system

NASA Technical Reports Server (NTRS)

Balakrishnan, Tanapaal; Bishop, Mike; Gumus, Ilker; Gussy, Joel; Triggs, Mike

1994-01-01

Design requirements for the cabin, cabin system, flight controls, engine installation, and wing-fuselage interface that provide adequate interior volume for occupant seating, cabin ingress and egress, and safety are presented. The fuselage structure must be sufficient to meet the loadings specified in the appropriate sections of Federal Aviation Regulation Part 23. The critical structure must provide a safe life of 10(exp 6) load cycles and 10,000 operational mission cycles. The cabin seating and controls must provide adjustment to account for various pilot physiques and to aid in maintenance and operation of the aircraft. Seats and doors shall not bind or lockup under normal operation. Cabin systems such as heating and ventilation, electrical, lighting, intercom, and avionics must be included in the design. The control system will consist of ailerons, elevator, and rudders. The system must provide required deflections with a combination of push rods, bell cranks, pulleys, and linkages. The system will be free from slack and provide smooth operation without binding. Environmental considerations include variations in temperature and atmospheric pressure, protection against sand, dust, rain, humidity, ice, snow, salt/fog atmosphere, wind and gusts, and shock and vibration. The following design goals were set to meet the requirements of the statement of work: safety, performance, manufacturing and cost. To prevent the engine from penetrating the passenger area in the event of a crash was the primary safety concern. Weight and the fuselage aerodynamics were the primary performance concerns. Commonality and ease of manufacturing were major considerations to reduce cost.

Investigating ozone-induced decomposition of surface-bound permethrin for conditions in aircraft cabins.

PubMed

Coleman, B K; Wells, J R; Nazaroff, W W

2010-02-01

The reaction of ozone with permethrin can potentially form phosgene. Published evidence on ozone levels and permethrin surface concentrations in aircraft cabins indicated that significant phosgene formation might occur in this setting. A derivatization technique was developed to detect phosgene with a lower limit of detection of 2 ppb. Chamber experiments were conducted with permethrin-coated materials (glass, carpet, seat fabric, and plastic) exposed to ozone under cabin-relevant conditions (150 ppb O(3), 4.5/h air exchange rate, <1% relative humidity, 1700 ng/cm(2) of permethrin). Phosgene was not detected in these experiments. Reaction of ozone with permethrin appears to be hindered by the electron-withdrawing chlorine atoms adjacent to the double bond in permethrin. Experimental results indicate that the upper limit on the reaction probability of ozone with surface-bound permethrin is approximately 10(-7). Extrapolation by means of material-balance modeling indicates that the upper limit on the phosgene level in aircraft cabins resulting from this chemistry is approximately 1 microg/m(3) or approximately 0.3 ppb. It was thus determined that phosgene formation, if it occurs in aircraft cabins, is not likely to exceed relevant, health-based phosgene exposure guidelines. Phosgene formation from ozone-initiated oxidation of permethrin in the aircraft cabin environment, if it occurs, is estimated to generate levels below the California Office of Environmental Health Hazard Assessment acute reference exposure level of 4 microg/m(3) or approximately 1 ppb.

Use of sorption technology for treatment of humidity condensate for potable water

NASA Technical Reports Server (NTRS)

Ajjarapu, Sundara R. M.; Symons, J. M.

1992-01-01

This research focused on the testing of the original potable water processor aboard Space Station Freedom that was to produce potable water from the humidity condensate and additional water generated by carbon dioxide reduction. Humidity condensate was simulated by an influent water model 'Ersatz'. The humidity condensate was treated with multifiltration (MF) beds that consisted of a train of sorption beds (referred to as 'Unibed') designed to remove specific contaminants. For the complete simulated MF system runs tested for 100 bed volumes (BV) (volume processed/total column volume), 0.6 percent of the TOC was removed by the SAC/IRN 77 (Strong Acid Cation exchange resin), 39.6 percent of the total organic carbon (TOC) was removed by the WBA/IRA 68 (Weak Base Anion exchange resin), 13.2 percent of the TOC was removed by activated carbon adsorption (580-26), and the remaining sorbent media acted as polishing units to remove an additional 1.6 percent of the TOC at steady state. At steady state, 45 percent of the influent TOC passed through the MF bed.

Analysis of heat and mass transfer during condensation over a porous substrate.

PubMed

Balasubramaniam, R; Nayagam, V; Hasan, M M; Khan, L

2006-09-01

Condensing heat exchangers are important in many space applications for thermal and humidity control systems. The International Space Station uses a cooled fin surface to condense moisture from humid air that is blown over it. The condensate and the air are "slurped" into a system that separates air and water by centrifugal forces. The use of a cooled porous substrate is an attractive alternative to the fin where condensation and liquid/gas separation can be achieved in a single step. We analyze the heat and mass transfer during condensation of moisture from flowing air over such a cooled, flat, porous substrate. A fully developed regime is investigated for coupled mass, momentum and energy transport in the gas phase, and momentum and energy transport in the condensate layer on the porous substrate and through the porous medium.

Personal Cabin Pressure Monitor and Warning System

NASA Technical Reports Server (NTRS)

Zysko, Jan A. (Inventor)

2002-01-01

A cabin pressure altitude monitor and warning system provides a warning when a detected cabin pressure altitude has reached a predetermined level. The system is preferably embodied in a portable, pager-sized device that can be carried or worn by an individual. A microprocessor calculates the pressure altitude from signals generated by a calibrated pressure transducer and a temperature sensor that compensates for temperature variations in the signals generated by the pressure transducer. The microprocessor is programmed to generate a warning or alarm if a cabin pressure altitude exceeding a predetermined threshold is detected. Preferably, the microprocessor generates two different types of warning or alarm outputs, a first early warning or alert when a first pressure altitude is exceeded. and a second more serious alarm condition when either a second. higher pressure altitude is exceeded, or when the first pressure altitude has been exceeded for a predetermined period of time. Multiple types of alarm condition indicators are preferably provided, including visual, audible and tactile. The system is also preferably designed to detect gas concentrations and other ambient conditions, and thus incorporates other sensors, such as oxygen, relative humidity, carbon dioxide, carbon monoxide and ammonia sensors, to provide a more complete characterization and monitoring of the local environment.

Personal Cabin Pressure Monitor and Warning System

NASA Astrophysics Data System (ADS)

Zysko, Jan A.

2002-09-01

A cabin pressure altitude monitor and warning system provides a warning when a detected cabin pressure altitude has reached a predetermined level. The system is preferably embodied in a portable, pager-sized device that can be carried or worn by an individual. A microprocessor calculates the pressure altitude from signals generated by a calibrated pressure transducer and a temperature sensor that compensates for temperature variations in the signals generated by the pressure transducer. The microprocessor is programmed to generate a warning or alarm if a cabin pressure altitude exceeding a predetermined threshold is detected. Preferably, the microprocessor generates two different types of warning or alarm outputs, a first early warning or alert when a first pressure altitude is exceeded. and a second more serious alarm condition when either a second. higher pressure altitude is exceeded, or when the first pressure altitude has been exceeded for a predetermined period of time. Multiple types of alarm condition indicators are preferably provided, including visual, audible and tactile. The system is also preferably designed to detect gas concentrations and other ambient conditions, and thus incorporates other sensors, such as oxygen, relative humidity, carbon dioxide, carbon monoxide and ammonia sensors, to provide a more complete characterization and monitoring of the local environment.

Chemical Analysis and Water Recovery Testing of Shuttle-Mir Humidity Condensate

NASA Technical Reports Server (NTRS)

Mudgett, Paul D.; Straub, John E., II; Schultz, John R.; Sauer, Richard L.; Williams, David E.; Bobe, L. S.; Novikov, V. M.; Andreichouk, P. O.; Protasov, N. N.

1999-01-01

Humidity condensate collected and processed in-flight is an important component of a space station drinking water supply. Water recovery systems in general are designed to handle finite concentrations of specific chemical components. Previous analyses of condensate derived from spacecraft and ground sources showed considerable variation in composition. Consequently, an investigation was conducted to collect condensate on the Shuttle while the vehicle was docked to Mir, and return the condensate to Earth for testing. This scenario emulates an early ISS configuration during a Shuttle docking, because the atmospheres intermix during docking and the condensate composition should reflect that. During the STS-89 and STS-91 flights, a total volume of 50 liters of condensate was collected and returned. Inorganic and organic chemical analyses were performed on aliquots of the fluid. Tests using the actual condensate were then conducted with scaled-down elements of the Russian condensate recovery system to determine the quality of water produced. The composition and test results are described, and implications for ISS are discussed.

Observation of airplane flow fields by natural condensation effects

NASA Technical Reports Server (NTRS)

Campbell, James F.; Chambers, Joseph R.; Rumsey, Christopher L.

1988-01-01

In-flight condensation patterns can illustrate a variety of airplane flow fields, such as attached and separated flows, vortex flows, and expansion and shock waves. These patterns are a unique source of flow visualization that has not been utilized previously. Condensation patterns at full-scale Reynolds number can provide useful information for researchers experimenting in subscale tunnels. It is also shown that computed values of relative humidity in the local flow field provide an inexpensive way to analyze the qualitative features of the condensation pattern, although a more complete theoretical modeling is necessary to obtain details of the condensation process. Furthermore, the analysis revealed that relative humidity is more sensitive to changes in local static temperature than to changes in pressure.

Measurement of Vehicle Air Conditioning Pull-Down Period

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thomas, John F.; Huff, Shean P.; Moore, Larry G.

2016-08-01

Air conditioner usage was characterized for high heat-load summer conditions during short driving trips using a 2009 Ford Explorer and a 2009 Toyota Corolla. Vehicles were parked in the sun with windows closed to allow the cabin to become hot. Experiments were conducted by entering the instrumented vehicles in this heated condition and driving on-road with the windows up and the air conditioning set to maximum cooling, maximum fan speed and the air flow setting to recirculate cabin air rather than pull in outside humid air. The main purpose was to determine the length of time the air conditioner systemmore » would remain at or very near maximum cooling power under these severe-duty conditions. Because of the variable and somewhat uncontrolled nature of the experiments, they serve only to show that for short vehicle trips, air conditioning can remain near or at full cooling capacity for 10-minutes or significantly longer and the cabin may be uncomfortably warm during much of this time.« less

Flight prototype CO2 and humidity control system

NASA Technical Reports Server (NTRS)

Rudy, K. M.

1979-01-01

A regenerable CO2 and humidity control system is presently being developed for potential use on shuttle as an alternative to the baseline lithium hydroxide system. The system utilizes a sorbent material (designated HS-C) to adsorb CO2 and the latent heat load from the cabin atmosphere and desorb the CO2 and water vapor overboard when exposed to a space vacuum, thus reducing the overall vehicle heat rejection load. Continuous operation is achieved by utilizing two beds which are alternatively cycled between adsorption and desorption. The HS-C material process was verified. Design concepts for the auxiliary components for the HS-C prototype system were generated. Performance testing verified system effectiveness in controlling CO2 partial pressure and humidity.

Measuring Relative Humidity.

ERIC Educational Resources Information Center

Pinkham, Chester A.; Barrett, Kristin Burrows

1992-01-01

Describes four experiments that enable students to explore the phenomena of evaporation and condensation and determine the relative humidity by measuring air temperature and dew point on warm September days. Provides tables to calculate saturation points and relative humidity. (MDH)

Disposable condenser humidifiers in intensive care.

PubMed

Oh, T E; Thompson, W R; Hayward, D R

1981-11-01

Two disposable condenser humidifiers were evaluated in nine ventilated intensive care patients. The Portex "Humid Vent" delivered end-inspired absolute humidities of 22--26.3 g/m3 at end-inspired temperatures of 27--28.3 degrees C. Corresponding humidities and temperatures with the Servo "Humidifier 150" were higher and were constant, at 27.7--29 g/m3 and 29.3--29.7 degrees C respectively. These disposable devices can be used for humidification in intensive care, but only for patients breathing room air, or on a short term basis.

Measuring Humidity in the Charters of Freedom Encasements Using a Moisture Condensation Method

NASA Technical Reports Server (NTRS)

Burkett, Cecil G.; West, James W.; Levine, Joel S.

2004-01-01

The relative humidity of the atmosphere in the encasements containing the U.S. Constitution Pages 1 and 4, the Declaration of Independence, and the Bill of Rights was measured to be in the range of 55% to 61%. This value is significantly higher than the presumed relative humidity between 25 to 35 %, but is consistent with the measured samples extracted from Pages 2 and 3 of the U.S. Constitution. The cooling/condensation measurement technique used at NARA on July 23, 2001, and described in this paper to measure the water vapor content of the atmosphere in the hermetically sealed encasements containing the U. S. Constitution, the Declaration of Independence, and the Bill of Rights, proved to be a powerful new measurement technique. The cooling/condensation technique developed at NASA LaRC and utilized at NARA has important applications in the non-invasive measurement of relative humidity in the atmospheres of sealed encasements and could become a standard measurement technique in this type of analysis.

[The balance of harmful trace contaminants between the air humidity condensate and air in a simulator of the Mir orbit station moisture condensation unit].

PubMed

Zlotopol'skiĭ, V M; Smolenskaia, T S

2000-01-01

Subject of the investigation was the balance of harmful trace contaminants (HTC) between the air moisture condensate and air in a simulator of the MIR moisture condensation unit. Experiments involved various classes of water-solvent compounds including alcohols (C1-C4), ketons (C1-C2), aldehydes (C1-C2), fatty acids (C2-C4), esters (acetates C4-C6), and ammonium. For most of the compounds, removal efficiency correlates with air humidity and virtually does not depend on the HTC concentration within the range of 0.25 to 59.1 mg/m3.

The time dependent growth of H2O-H2SO4 aerosols by heteromolecular condensation

NASA Technical Reports Server (NTRS)

Hamill, P.

1975-01-01

A theory for the time-dependent growth of solution droplets by heteromolecular condensation is presented. The theory is applied to the growth of H2O-H2SO4 aerosols for relative humidities less than 100 per cent. Growth curves (droplet radius as a function of time) for different values of relative humidity are evaluated.

Desiccant humidity control system. [for space shuttle cabins

NASA Technical Reports Server (NTRS)

Lunde, P. J.; Kester, F. L.

1975-01-01

A water vapor and carbon dioxide sorbent material (designated HS-C) was developed for potential application to the space shuttle and tested at full scale. Capacities of two percent for carbon dioxide and four percent for water vapor were achieved using space shuttle cabin adsorption conditions and a space vacuum for desorption. Performance testing shows that water vapor can be controlled by varying the air process flow, while maintaining the ability to remove carbon dioxide. A 2000 hour life test was successfully completed, as were tests for sensitivity to cleaning solvent vapors, vibration resistance, and flammability. A system design for the space shuttle shows a 200 pound weight advantage over competitive systems and an even larger advantage for longer missions.

Conceptual Design of a Condensing Heat Exchanger for Space Systems Using Porous Media

NASA Technical Reports Server (NTRS)

Hasan, Mohammad M.; Khan, Lutful I.; Nayagam, Vedha; Balasubramaniam, Ramaswamy

2006-01-01

Condensing heat exchangers are used in many space applications in the thermal and humidity control systems. In the International Space Station (ISS), humidity control is achieved by using a water cooled fin surface over which the moist air condenses, followed by "slurper bars" that take in both the condensate and air into a rotary separator and separates the water from air. The use of a cooled porous substrate as the condensing surface provides and attractive alternative that combines both heat removal as well as liquid/gas separation into a single unit. By selecting the pore sizes of the porous substrate a gravity independent operation may also be possible with this concept. Condensation of vapor into and on the porous surface from the flowing air and the removal of condensate from the porous substrate are the critical processes involved in the proposed concept. This paper describes some preliminary results of the proposed condensate withdrawal process and discusses the on-going design and development work of a porous media based condensing heat exchanger at the NASA Glenn Research Center in collaboration with NASA Johnson Space Center.

A Radiosonde Using a Humidity Sensor Array with a Platinum Resistance Heater and Multi-Sensor Data Fusion

PubMed Central

Shi, Yunbo; Luo, Yi; Zhao, Wenjie; Shang, Chunxue; Wang, Yadong; Chen, Yinsheng

2013-01-01

This paper describes the design and implementation of a radiosonde which can measure the meteorological temperature, humidity, pressure, and other atmospheric data. The system is composed of a CPU, microwave module, temperature sensor, pressure sensor and humidity sensor array. In order to effectively solve the humidity sensor condensation problem due to the low temperatures in the high altitude environment, a capacitive humidity sensor including four humidity sensors to collect meteorological humidity and a platinum resistance heater was developed using micro-electro-mechanical-system (MEMS) technology. A platinum resistance wire with 99.999% purity and 0.023 mm in diameter was used to obtain the meteorological temperature. A multi-sensor data fusion technique was applied to process the atmospheric data. Static and dynamic experimental results show that the designed humidity sensor with platinum resistance heater can effectively tackle the sensor condensation problem, shorten response times and enhance sensitivity. The humidity sensor array can improve measurement accuracy and obtain a reliable initial meteorological humidity data, while the multi-sensor data fusion technique eliminates the uncertainty in the measurement. The radiosonde can accurately reflect the meteorological changes. PMID:23857263

A radiosonde using a humidity sensor array with a platinum resistance heater and multi-sensor data fusion.

PubMed

Shi, Yunbo; Luo, Yi; Zhao, Wenjie; Shang, Chunxue; Wang, Yadong; Chen, Yinsheng

2013-07-12

This paper describes the design and implementation of a radiosonde which can measure the meteorological temperature, humidity, pressure, and other atmospheric data. The system is composed of a CPU, microwave module, temperature sensor, pressure sensor and humidity sensor array. In order to effectively solve the humidity sensor condensation problem due to the low temperatures in the high altitude environment, a capacitive humidity sensor including four humidity sensors to collect meteorological humidity and a platinum resistance heater was developed using micro-electro-mechanical-system (MEMS) technology. A platinum resistance wire with 99.999% purity and 0.023 mm in diameter was used to obtain the meteorological temperature. A multi-sensor data fusion technique was applied to process the atmospheric data. Static and dynamic experimental results show that the designed humidity sensor with platinum resistance heater can effectively tackle the sensor condensation problem, shorten response times and enhance sensitivity. The humidity sensor array can improve measurement accuracy and obtain a reliable initial meteorological humidity data, while the multi-sensor data fusion technique eliminates the uncertainty in the measurement. The radiosonde can accurately reflect the meteorological changes.

Development Status of the Carbon Dioxide and Moisture Removal Amine Swing-Bed System (CAMRAS)

NASA Technical Reports Server (NTRS)

Papale, William; Nalette Tim; Sweterlitsch, Jeffrey

2009-01-01

Under a cooperative agreement with NASA, Hamilton Sundstrand has successfully designed, fabricated, tested and delivered three, state-of-the-art, solid amine prototype systems capable of continuous CO2 and humidity removal from a closed, habitable atmosphere. Two prototype systems (CAMRAS #1 and #2) incorporated a linear spool valve design for process flow control through the sorbent beds, with the third system (CAMRAS #3) employing a rotary valve assembly that improves system fluid interfaces and regeneration capabilities. The operational performance of CAMRAS #1 and #2 has been validated in a relevant environment, through both simulated human metabolic loads in a closed chamber and through human subject testing in a closed environment. Performance testing at Hamilton Sundstrand on CAMRAS #3, which incorporates a new valve and modified canister design, showed similar CO2 and humidity removal performance as CAMRAS #1 and #2, demonstrating that the system form can be modified within certain bounds with little to no effect in system function or performance. Demonstration of solid amine based CO2 and humidity control is an important milestone in developing this technology for human spaceflight. The systems have low power requirements; with power for air flow and periodic valve actuation and indication the sole requirements. Each system occupies the same space as roughly four shuttle non-regenerative LiOH canisters, but have essentially indefinite CO2 removal endurance provided a regeneration pathway is available. Using the solid amine based systems to control cabin humidity also eliminates the latent heat burden on cabin thermal control systems and the need for gas/liquid phase separation in a low gravity environment, resulting in additional simplification of vehicle environmental control and life support system process requirements.

Fiber optic humidity sensor using water vapor condensation.

PubMed

Limodehi, Hamid E; Légaré, François

2017-06-26

The rate of vapor condensation on a solid surface depends on the ambient relative humidity (RH). Also, surface plasmon resonance (SPR) on a metal layer is sensitive to the refractive index change of its adjacent dielectric. The SPR effect appears as soon as a small amount of moisture forms on the sensor, resulting in a decrease in the amount of light transmitted due to plasmonic loss. Using this concept, we developed a fiber optic humidity sensor based on SPR. It can measure the ambient RH over a dynamic range from 10% to 85% with an accuracy of 3%.

Cloud condensation nucleus counter by impactor sampling technique

NASA Technical Reports Server (NTRS)

Ohtake, T.

1981-01-01

Unlike typical CCN counters, this device counts the numbers of water droplets condensed on aerosol particles sampled on a microcover glass at various different relative humidities. The relative humidities ranged from 75 percent to a calculated value of 110 percent. A schematic of the apparatus is shown. The individual CCN can be identified in an optical micrograph and scanning electron micrograph and may be inspected for their chemical composition later.

Dueling Mechanisms for Dry Zones around Frozen Droplets

NASA Astrophysics Data System (ADS)

Bisbano, Caitlin; Nath, Saurabh; Boreyko, Jonathan

2016-11-01

Ice acts as a local humidity sink, due to its depressed saturation pressure relative to that of supercooled water. Hygroscopic chemicals typically exhibit annular dry zones of inhibited condensation; however, dry zones do not tend to form around ice because of inter-droplet frost growth to nearby liquid droplets that have already condensed on the chilled surface. Here, we use a humidity chamber with an embedded Peltier stage to initially suppress the growth of condensation on a chilled surface containing a single frozen droplet, in order to characterize the dry zone around ice for the first time. The length of the dry zone was observed to vary by at least two orders of magnitude as a function of surface temperature, ambient humidity, and the size of the frozen droplet. The surface temperature and ambient humidity govern the magnitudes of the in-plane and out-of-plane gradients in vapor pressure, while the size of the frozen droplet effects the local thickness of the concentration boundary layer. We develop an analytical model that reveals two different types of dry zones are possible: one in which nucleation is inhibited and one where the net growth of condensate is inhibited. Finally, a phase map was developed to predict the parameter space in which nucleation dry zones versus flux dry zones are dominant.

24 CFR 3280.504 - Condensation control and installation of vapor retarders.

Code of Federal Regulations, 2011 CFR

2011-04-01

... these cavities; or (4) Homes manufactured to be sited in “humid climates” or “fringe climates” as shown on the Humid and Fringe Climate Map in this paragraph are permitted to have a vapor retarder... the humid and fringe climate areas shown on the Humid and Fringe Climate Map in paragraph (b)(4) of...

24 CFR 3280.504 - Condensation control and installation of vapor retarders.

Code of Federal Regulations, 2013 CFR

2013-04-01

... these cavities; or (4) Homes manufactured to be sited in “humid climates” or “fringe climates” as shown on the Humid and Fringe Climate Map in this paragraph are permitted to have a vapor retarder... the humid and fringe climate areas shown on the Humid and Fringe Climate Map in paragraph (b)(4) of...

24 CFR 3280.504 - Condensation control and installation of vapor retarders.

Code of Federal Regulations, 2014 CFR

2014-04-01

... be sited in “humid climates” or “fringe climates” as shown on the Humid and Fringe Climate Map in... specified), listed by state are deemed to be within the humid and fringe climate areas shown on the Humid and Fringe Climate Map in paragraph (b)(4) of this section, and the vapor retarder or construction...

24 CFR 3280.504 - Condensation control and installation of vapor retarders.

Code of Federal Regulations, 2012 CFR

2012-04-01

... these cavities; or (4) Homes manufactured to be sited in “humid climates” or “fringe climates” as shown on the Humid and Fringe Climate Map in this paragraph are permitted to have a vapor retarder... the humid and fringe climate areas shown on the Humid and Fringe Climate Map in paragraph (b)(4) of...

24 CFR 3280.504 - Condensation control and installation of vapor retarders.

Code of Federal Regulations, 2010 CFR

2010-04-01

... these cavities; or (4) Homes manufactured to be sited in “humid climates” or “fringe climates” as shown on the Humid and Fringe Climate Map in this paragraph are permitted to have a vapor retarder... the humid and fringe climate areas shown on the Humid and Fringe Climate Map in paragraph (b)(4) of...

Assessment of the Microbial Control Measures for the Temperature and Humidity Control Subsystem Condensing Heat Exchanger of the International Space Station

NASA Technical Reports Server (NTRS)

Roman, Monsi C.; Steele, John W.; Marsh, Robert W.; Callahan, David M.; VonJouanne, Roger G.

1999-01-01

In August 1997 NASA/ Marshall Space Flight Center (MSFC) began a test with the objective of monitoring the growth of microorganisms on material simulating the surface of the International Space Station (ISS) Temperature and Humidity Control (THC) Condensing Heat Exchanger (CHX). The test addressed the concerns of potential uncontrolled microbial growth on the surface of the THC CHX subsystem. For this study, humidity condensate from a closed manned environment was used as a direct challenge to the surfaces of six cascades in a test set-up. The condensate was collected using a Shuttle-type CHX within the MSFC End-Use Equipment Testing Facility. Panels in four of the six cascades tested were coated with the ISS CHX silver impregnated hydrophilic coating. The remainder two cascade panels were coated with the hydrophilic coating without the antimicrobial component, silver. Results of the fourteen-month study are discussed in this paper. The effects on the microbial population when drying vs. not-drying the simulated THC CHX surface are also discussed.

Heat and mass transfer analogy for condensation of humid air in a vertical channel

NASA Astrophysics Data System (ADS)

Desrayaud, G.; Lauriat, G.

This study examines energy transport associated with liquid film condensation in natural convection flows driven by differences in density due to temperature and concentration gradients. The condensation problem is based on the thin-film assumptions. The most common compositional gradient, which is encountered in humid air at ambient temperature is considered. A steady laminar Boussinesq flow of an ideal gas-vapor mixture is studied for the case of a vertical parallel plate channel. New correlations for the latent and sensible Nusselt numbers are established, and the heat and mass transfer analogy between the sensible Nusselt number and Sherwood number is demonstrated.

Complication Rates in Altitude Restricted Patients Following Aeromedical Evacuation

DTIC Science & Technology

2016-04-01

humidity and temperature , reduced barometric pressure and oxygen levels, increased vibration, trapped gas expansion, and serious n oise, not to...correlated to PFC and PFC-100 rates. This finding suggests that aggressive prescribing of CARs may have a salutary effect on postflight complication...suggests that aggressive prescribing of CARs may have a salutary effect on postflight complication rates and bears further investigation. KEYWORDS: cabin

Influence of a controlled environment simulating an in-flight airplane cabin on dry eye disease.

PubMed

Tesón, Marisa; González-García, María J; López-Miguel, Alberto; Enríquez-de-Salamanca, Amalia; Martín-Montañez, Vicente; Benito, María Jesús; Mateo, María Eugenia; Stern, Michael E; Calonge, Margarita

2013-03-01

To evaluate symptoms, signs, and the levels of 16 tears inflammatory mediators of dry eye (DE) patients exposed to an environment simulating an in-flight air cabin in an environmental chamber. Twenty DE patients were exposed to controlled environment simulating an in-flight airplane cabin (simulated in-flight condition [SIC]) of 23°C, 5% relative humidity, localized air flow, and 750 millibars (mb) of barometric pressure. As controls, 15 DE patients were subjected to a simulated standard condition (SSC) of 23°C, 45% relative humidity, and 930 mb. A DE symptoms questionnaire, diagnostic tests, and determination of 16 tear molecules by multiplex bead array were performed before and 2 hours after exposure. After SIC exposure, DE patients became more symptomatic, suffered a significant (P ≤ 0.05) decrease in tear stability (tear break up time) (from 2.18 ± 0.28 to 1.53 ± 0.20), and tear volume (phenol red thread test), and a significant (P ≤ 0.05) increase in corneal staining, both globally (0.50 ± 0.14 before and 1.25 ± 0.19 after) and in each area (Baylor scale). After SSC, DE patients only showed a mild, but significant (P ≤ 0.05), increase in central and inferior corneal staining. Consistently, tear levels of IL-6 and matrix metalloproteinase (MMP)-9 significantly increased and tear epidermal growth factor (EGF) significantly decreased (P ≤ 0.05) only after SIC. The controlled adverse environment conditions in this environmental chamber can simulate the conditions in which DE patients might be exposed during flight. As this clearly impaired their lacrimal functional unit, it would be advisable that DE patients use therapeutic strategies capable of ameliorating these adverse episodes.

Comparison of nonwoven fiberglass and stainless steel microfiber media in aerosol coalescence filtration

NASA Astrophysics Data System (ADS)

Manzo, Gabriel

Coalescing filters are used to remove small liquid droplets from air streams. They have numerous industrial applications including dehumidification, cabin air filtration, compressed air filtration, metal working, CCV, and agriculture. In compressed air systems, oils used for lubrication of compressor parts can aerosolize into the main air stream causing potential contamination concerns for downstream applications. In many systems, humid air can present problems to sensitive equipment and sensors. As the humid air cools, small water drops condense and can disrupt components that need to be kept dry. Fibrous nonwoven filter media are commonly used to coalesce small drops into larger drops for easier removal. The coalescing performance of a medium is dependent upon several parameters including permeability, porosity, and wettability. In many coalescing filters, glass fibers are used. In this work, the properties of steel fiber media are measured to see how these properties compare to glass fiber media. Steel fiber media has different permeability, porosity and wettability to oil and water than fiber glass media. These differences can impact coalescence performance. The impact of these differences in properties on coalescence filtration performance was evaluated in a coalescence test apparatus. The overall coalescence performance of the steel and glass nonwoven fiber media are compared using a filtration efficiency and filtration index. In many cases, the stainless steel media performed comparably to fiber glass media with efficiencies near 90%. Since stainless steel media had lower pressure drops than fiber glass media, its filtration index values were significantly higher. Broader impact of this work is the use of stainless steel fiber media as an alternative to fiber glass media in applications where aerosol filtration is needed to protect the environment or sensitive equipment and sensors.

Adsorption processes in spacecraft environmental control and life support systems

NASA Technical Reports Server (NTRS)

DallBauman, L. A.; Finn, J. E.

1999-01-01

The environmental control and life support system on a spacecraft maintains a safe and comfortable environment in which the crew can live and work by supplying oxygen and water and by removing carbon dioxide, water vapor, and trace contaminants from cabin air. Although open-loop systems have been used successfully in the past for short-duration missions, the economics of current and future long-duration missions in space will make nearly complete recycling of air and water imperative. A variety of operations will be necessary to achieve the goal of nearly complete recycling. These include separation and reduction of carbon dioxide, removal of trace gas-phase contaminants, recovery and purification of humidity condensate, purification and polishing of wastewater streams, and others. Several of these can be performed totally or in part by adsorption processes. These processes are good candidates to perform separations and purifications in space due to their gravity independence, high reliability, relative high energy efficiency, design flexibility, technological maturity, and regenerative nature. For these reasons, adsorption has historically played a key role in life support on U.S. and Russian piloted spacecraft. Among the life support applications that can be achieved through use of adsorption technology are removal of trace contaminants and carbon dioxide from cabin air and recovery of potable water from waste streams. In each of these cases adsorption technology has been selected for use onboard the International Space Station. The requirements, science, and hardware for these applications are discussed. Human space exploration may eventually lead to construction of planetary habitats. These habitats may provide additional opportunities for use of adsorption processes, such as control of greenhouse gas composition, and may have different resources available to them, such as gases present in the planetary atmosphere. Separation and purification processes based on adsorption can be expected to continue to fulfill environmental control and life support needs on future missions.

Adsorption processes in spacecraft environmental control and life support systems.

PubMed

DallBauman, L A; Finn, J E

1999-01-01

The environmental control and life support system on a spacecraft maintains a safe and comfortable environment in which the crew can live and work by supplying oxygen and water and by removing carbon dioxide, water vapor, and trace contaminants from cabin air. Although open-loop systems have been used successfully in the past for short-duration missions, the economics of current and future long-duration missions in space will make nearly complete recycling of air and water imperative. A variety of operations will be necessary to achieve the goal of nearly complete recycling. These include separation and reduction of carbon dioxide, removal of trace gas-phase contaminants, recovery and purification of humidity condensate, purification and polishing of wastewater streams, and others. Several of these can be performed totally or in part by adsorption processes. These processes are good candidates to perform separations and purifications in space due to their gravity independence, high reliability, relative high energy efficiency, design flexibility, technological maturity, and regenerative nature. For these reasons, adsorption has historically played a key role in life support on U.S. and Russian piloted spacecraft. Among the life support applications that can be achieved through use of adsorption technology are removal of trace contaminants and carbon dioxide from cabin air and recovery of potable water from waste streams. In each of these cases adsorption technology has been selected for use onboard the International Space Station. The requirements, science, and hardware for these applications are discussed. Human space exploration may eventually lead to construction of planetary habitats. These habitats may provide additional opportunities for use of adsorption processes, such as control of greenhouse gas composition, and may have different resources available to them, such as gases present in the planetary atmosphere. Separation and purification processes based on adsorption can be expected to continue to fulfill environmental control and life support needs on future missions.

Low Temperature Catalyst for NH3 Removal

NASA Technical Reports Server (NTRS)

Monje, Oscar; Melendez, Orlando

2013-01-01

Air revitalization technologies maintain a safe atmosphere inside spacecraft by the removal of C02, ammonia (NH3), and trace contaminants. NH3 onboard the International Space Station (ISS) is produced by crew metabolism, payloads, or during an accidental release of thermal control refrigerant. Currently, the ISS relies on removing NH3 via humidity condensate and the crew wears hooded respirators during emergencies. A different approach to cabin NH3 removal is to use selective catalytic oxidation (SCO), which builds on thermal catalytic oxidation concepts that could be incorporated into the existing TCCS process equipment architecture on ISS. A low temperature platinum-based catalyst (LTP-Catalyst) developed at KSC was used for converting NH3 to H20 and N2 gas by SCO. The challenge of implementing SCO is to reduce formation of undesirable byproducts like NOx (N20 and NO). Gas mixture analysis was conducted using FTIR spectrometry in the Regenerable VOC Control System (RVCS) Testbed. The RVCS was modified by adding a 66 L semi-sealed chamber, and a custom NH3 generator. The effect of temperature on NH3 removal using the LTP-Catalyst was examined. A suitable temperature was found where NH3 removal did not produce toxic NO, (NO, N02) and N20 formation was reduced.

Patterns in the sky: Natural visualization of aircraft flow fields

NASA Technical Reports Server (NTRS)

Campbell, James F.; Chambers, Joseph R.

1994-01-01

The objective of the current publication is to present the collection of flight photographs to illustrate the types of flow patterns that were visualized and to present qualitative correlations with computational and wind tunnel results. Initially in section 2, the condensation process is discussed, including a review of relative humidity, vapor pressure, and factors which determine the presence of visible condensate. Next, outputs from computer code calculations are postprocessed by using water-vapor relationships to determine if computed values of relative humidity in the local flow field correlate with the qualitative features of the in-flight condensation patterns. The photographs are then presented in section 3 by flow type and subsequently in section 4 by aircraft type to demonstrate the variety of condensed flow fields that was visualized for a wide range of aircraft and flight maneuvers.

36 CFR 1234.14 - What are the requirements for environmental controls for records storage facilities?

Code of Federal Regulations, 2014 CFR

2014-07-01

... through leaks or condensation, relative humidities in excess of 70%, extremes of heat combined with relative humidity in excess of 55%, and poor air circulation during periods of elevated heat and relative humidity are all factors that contribute to mold growth. (b) Nontextual temporary records. Nontextual...

36 CFR § 1234.14 - What are the requirements for environmental controls for records storage facilities?

Code of Federal Regulations, 2013 CFR

2013-07-01

... through leaks or condensation, relative humidities in excess of 70%, extremes of heat combined with relative humidity in excess of 55%, and poor air circulation during periods of elevated heat and relative humidity are all factors that contribute to mold growth. (b) Nontextual temporary records. Nontextual...

36 CFR 1234.14 - What are the requirements for environmental controls for records storage facilities?

Code of Federal Regulations, 2012 CFR

2012-07-01

... through leaks or condensation, relative humidities in excess of 70%, extremes of heat combined with relative humidity in excess of 55%, and poor air circulation during periods of elevated heat and relative humidity are all factors that contribute to mold growth. (b) Nontextual temporary records. Nontextual...

Comparing on-road real-time simultaneous in-cabin and outdoor particulate and gaseous concentrations for a range of ventilation scenarios

NASA Astrophysics Data System (ADS)

Leavey, Anna; Reed, Nathan; Patel, Sameer; Bradley, Kevin; Kulkarni, Pramod; Biswas, Pratim

2017-10-01

Advanced automobile technology, developed infrastructure, and changing economic markets have resulted in increasing commute times. Traffic is a major source of harmful pollutants and consequently daily peak exposures tend to occur near roadways or while travelling on them. The objective of this study was to measure simultaneous real-time particulate matter (particle numbers, lung-deposited surface area, PM2.5, particle number size distributions) and CO concentrations outside and in-cabin of an on-road car during regular commutes to and from work. Data was collected for different ventilation parameters (windows open or closed, fan on, AC on), whilst travelling along different road-types with varying traffic densities. Multiple predictor variables were examined using linear mixed-effects models. Ambient pollutants (NOx, PM2.5, CO) and meteorological variables (wind speed, temperature, relative humidity, dew point) explained 5-44% of outdoor pollutant variability, while the time spent travelling behind a bus was statistically significant for PM2.5, lung-deposited SA, and CO (adj-R2 values = 0.12, 0.10, 0.13). The geometric mean diameter (GMD) for outdoor aerosol was 34 nm. Larger cabin GMDs were observed when windows were closed compared to open (b = 4.3, p-value = <0.01). When windows were open, cabin total aerosol concentrations tracked those outdoors. With windows closed, the pollutants took longer to enter the vehicle cabin, but also longer to exit it. Concentrations of pollutants in cabin were influenced by outdoor concentrations, ambient temperature, and the window/ventilation parameters. As expected, particle number concentrations were impacted the most by changes to window position/ventilation, and PM2.5 the least. Car drivers can expect their highest exposures when driving with windows open or the fan on, and their lowest exposures during windows closed or the AC on. Final linear mixed-effects models could explain between 88 and 97% of cabin pollutant concentration variability. An individual may control their commuting exposure by applying dynamic behavior modification to adapt to changing pollutant scenarios.

Comparing on-road real-time simultaneous in-cabin and outdoor particulate and gaseous concentrations for a range of ventilation scenarios

PubMed Central

Leavey, Anna; Reed, Nathan; Patel, Sameer; Bradley, Kevin; Kulkarni, Pramod; Biswas, Pratim

2017-01-01

Advanced automobile technology, developed infrastructure, and changing economic markets have resulted in increasing commute times. Traffic is a major source of harmful pollutants and consequently daily peak exposures tend to occur near roadways or while traveling on them. The objective of this study was to measure simultaneous real-time particulate matter (particle numbers, lung-deposited surface area, PM2.5, particle number size distributions) and CO concentrations outside and in-cabin of an on-road car during regular commutes to and from work. Data was collected for different ventilation parameters (windows open or closed, fan on, AC on), whilst traveling along different road-types with varying traffic densities. Multiple predictor variables were examined using linear mixed-effects models. Ambient pollutants (NOx, PM2.5, CO) and meteorological variables (wind speed, temperature, relative humidity, dew point) explained 5–44% of outdoor pollutant variability, while the time spent travelling behind a bus was statistically significant for PM2.5, lung-deposited SA, and CO (adj-R2 values = 0.12, 0.10, 0.13). The geometric mean diameter (GMD) for outdoor aerosol was 34 nm. Larger cabin GMDs were observed when windows were closed compared to open (b = 4.3, p-value = <0.01). When windows were open, cabin total aerosol concentrations tracked those outdoors. With windows closed, the pollutants took longer to enter the vehicle cabin, but also longer to exit it. Concentrations of pollutants in cabin were influenced by outdoor concentrations, ambient temperature, and the window/ventilation parameters. As expected, particle number concentrations were impacted the most by changes to window position / ventilation, and PM2.5 the least. Car drivers can expect their highest exposures when driving with windows open or the fan on, and their lowest exposures during windows closed or the AC on. Final linear mixed-effects models could explain between 88–97% of cabin pollutant concentration variability. An individual may control their commuting exposure by applying dynamic behavior modification to adapt to changing pollutant scenarios. PMID:29284988

Comparing on-road real-time simultaneous in-cabin and outdoor particulate and gaseous concentrations for a range of ventilation scenarios.

PubMed

Leavey, Anna; Reed, Nathan; Patel, Sameer; Bradley, Kevin; Kulkarni, Pramod; Biswas, Pratim

2017-10-01

Advanced automobile technology, developed infrastructure, and changing economic markets have resulted in increasing commute times. Traffic is a major source of harmful pollutants and consequently daily peak exposures tend to occur near roadways or while traveling on them. The objective of this study was to measure simultaneous real-time particulate matter (particle numbers, lung-deposited surface area, PM 2.5 , particle number size distributions) and CO concentrations outside and in-cabin of an on-road car during regular commutes to and from work. Data was collected for different ventilation parameters (windows open or closed, fan on, AC on), whilst traveling along different road-types with varying traffic densities. Multiple predictor variables were examined using linear mixed-effects models. Ambient pollutants (NO x , PM 2.5 , CO) and meteorological variables (wind speed, temperature, relative humidity, dew point) explained 5-44% of outdoor pollutant variability, while the time spent travelling behind a bus was statistically significant for PM 2.5, lung-deposited SA, and CO (adj-R 2 values = 0.12, 0.10, 0.13). The geometric mean diameter (GMD) for outdoor aerosol was 34 nm. Larger cabin GMDs were observed when windows were closed compared to open (b = 4.3, p-value = <0.01). When windows were open, cabin total aerosol concentrations tracked those outdoors. With windows closed, the pollutants took longer to enter the vehicle cabin, but also longer to exit it. Concentrations of pollutants in cabin were influenced by outdoor concentrations, ambient temperature, and the window/ventilation parameters. As expected, particle number concentrations were impacted the most by changes to window position / ventilation, and PM 2.5 the least. Car drivers can expect their highest exposures when driving with windows open or the fan on, and their lowest exposures during windows closed or the AC on. Final linear mixed-effects models could explain between 88-97% of cabin pollutant concentration variability. An individual may control their commuting exposure by applying dynamic behavior modification to adapt to changing pollutant scenarios.

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

NASA Technical Reports Server (NTRS)

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.

Design, Development, and Testing of a Water Vapor Exchanger for Spacecraft Life Support Systems

NASA Technical Reports Server (NTRS)

Izenson, Michael G.; Micka, Daniel J.; Chepko, Ariane B.; Rule, Kyle C.; Anderson, Molly S.

2016-01-01

Thermal and environmental control systems for future exploration spacecraft must meet challenging requirements for efficient operation and conservation of resources. Maximizing the use of regenerative systems and conserving water are critical considerations. This paper describes the design, development, and testing of an innovative water vapor exchanger (WVX) that can minimize the amount of water absorbed in, and vented from, regenerative CO2 removal systems. Key design requirements for the WVX are high air flow capacity (suitable for a crew of six), very high water recovery, and very low pressure losses. We developed fabrication and assembly methods that enable high-efficiency mass transfer in a uniform and stable array of Nafion tubes. We also developed analysis and design methods to compute mass transfer and pressure losses. We built and tested subscale units sized for flow rates of 2 and 5 cu ft/min (3.4–8.5 cu m/hr). Durability testing demonstrated that a stable core geometry was sustained over many humid/dry cycles. Pressure losses were very low (less than 0.5 in. H2O (125 Pa) total) and met requirements at prototypical flow rates. We measured water recovery efficiency across a range of flow rates and humidity levels that simulate the range of possible cabin conditions. We measured water recovery efficiencies in the range of 80 to 90%, with the best efficiency at lower flow rates and higher cabin humidity levels. We compared performance of the WVX with similar units built using an unstructured Nafion tube bundle. The WVX achieves higher water recovery efficiency with nearly an order of magnitude lower pressure drop than unstructured tube bundles. These results show that the WVX provides uniform flow through flow channels for both the humid and dry streams and can meet requirements for service on future exploration spacecraft. The WVX technology will be best suited for long-duration exploration vehicles that require regenerative CO2 removal systems while needing to conserve water.

Thermo-Physiological Responses of Sailors in a Disabled Submarine with Interior Cabin Temperature and Humidity Slowly Rising as Predicted by Computer Simulation Techniques

DTIC Science & Technology

2013-09-01

define CSTR .5 // 1/°C #define SKBFN 6.3 // liters/(h m^2) #define Skbfmax 90. // conservative could be higher for fit person 36 #define...WarmC=0; if (Tsk<TTSK) Colds=TTSK-Tsk; if (Tc>TTCR) WarmC=Tc-TTCR; Skbf=(SKBFN+CDIL*WarmC)/(1+ CSTR *Colds); // Liters/(h m^2) if (Skbf

Increased water retention in polymer electrolyte membranes at elevated temperatures assisted by capillary condensation.

PubMed

Park, Moon Jeong; Downing, Kenneth H; Jackson, Andrew; Gomez, Enrique D; Minor, Andrew M; Cookson, David; Weber, Adam Z; Balsara, Nitash P

2007-11-01

We establish a new systematic methodology for controlling the water retention of polymer electrolyte membranes. Block copolymer membranes comprising hydrophilic phases with widths ranging from 2 to 5 nm become wetter as the temperature of the surrounding air is increased at constant relative humidity. The widths of the moist hydrophilic phases were measured by cryogenic electron microscopy experiments performed on humid membranes. Simple calculations suggest that capillary condensation is important at these length scales. The correlation between moisture content and proton conductivity of the membranes is demonstrated.

A Fine-Tuned Metal-Organic Framework for Autonomous Indoor Moisture Control.

PubMed

AbdulHalim, Rasha G; Bhatt, Prashant M; Belmabkhout, Youssef; Shkurenko, Aleksander; Adil, Karim; Barbour, Leonard J; Eddaoudi, Mohamed

2017-08-09

Conventional adsorbents, namely zeolites and silica gel, are often used to control humidity by adsorbing water; however, adsorbents capable of the dual functionality of humidification and dehumidification, offering the desired control of the moisture level at room temperature, have yet to be explored. Here we report Y-shp-MOF-5, a hybrid microporous highly connected rare-earth-based metal-organic framework (MOF), with dual functionality for moisture control within the recommended range of relative humidity (45%-65% RH) set by the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE). Y-shp-MOF-5 exhibits exceptional structural integrity, robustness, and unique humidity-control performance, as confirmed by the large number (thousand) of conducted water vapor adsorption-desorption cycles. The retained structural integrity and the mechanism of water sorption were corroborated using in situ single-crystal X-ray diffraction (SCXRD) studies. The resultant working water uptake of 0.45 g·g -1 is solely regulated by a simple adjustment of the relative humidity, positioning this hydrolytically stable MOF as a prospective adsorbent for humidity control in confined spaces, such as space shuttles, aircraft cabins, and air-conditioned buildings.

Development of a Next-Generation Membrane-Integrated Adsorption Processor for CO2 Removal and Compression for Closed-Loop Air Revitalization Systems

NASA Technical Reports Server (NTRS)

Mulloth, Lila; LeVan, Douglas

2002-01-01

The current CO2 removal technology of NASA is very energy intensive and contains many non-optimized subsystems. This paper discusses the concept of a next-generation, membrane integrated, adsorption processor for CO2 removal nd compression in closed-loop air revitalization systems. This processor will use many times less power than NASA's current CO2 removal technology and will be capable of maintaining a lower CO2 concentration in the cabin than that can be achieved by the existing CO2 removal systems. The compact, consolidated, configuration of gas dryer, CO2 separator, and CO2 compressor will allow continuous recycling of humid air in the cabin and supply of compressed CO2 to the reduction unit for oxygen recovery. The device has potential application to the International Space Station and future, long duration, transit, and planetary missions.

Characterization of simultaneous heat and mass transfer phenomena for water vapour condensation on a solid surface in an abiotic environment--application to bioprocesses.

PubMed

Tiwari, Akhilesh; Kondjoyan, Alain; Fontaine, Jean-Pierre

2012-07-01

The phenomenon of heat and mass transfer by condensation of water vapour from humid air involves several key concepts in aerobic bioreactors. The high performance of bioreactors results from optimised interactions between biological processes and multiphase heat and mass transfer. Indeed in various processes such as submerged fermenters and solid-state fermenters, gas/liquid transfer need to be well controlled, as it is involved at the microorganism interface and for the control of the global process. For the theoretical prediction of such phenomena, mathematical models require heat and mass transfer coefficients. To date, very few data have been validated concerning mass transfer coefficients from humid air inflows relevant to those bioprocesses. Our study focussed on the condensation process of water vapour and developed an experimental set-up and protocol to study the velocity profiles and the mass flux on a small size horizontal flat plate in controlled environmental conditions. A closed circuit wind tunnel facility was used to control the temperature, hygrometry and hydrodynamics of the flow. The temperature of the active surface was controlled and kept isothermal below the dew point to induce condensation, by the use of thermoelectricity. The experiments were performed at ambient temperature for a relative humidity between 35-65% and for a velocity of 1.0 ms⁻¹. The obtained data are analysed and compared to available theoretical calculations on condensation mass flux.

Extended Pulse-Powered Humidity-Freeze Cycling for Testing Module-Level Power Electronics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hacke, Peter L; Rodriguez, Miguel; Kempe, Michael D

An EMI suppression capacitor (polypropylene film type) failed by 'popcorning' due to vapor outgassing in pulse powered humidity-freeze cycles. No shorts or shunts could be detected despite mildly corroded metallization visible in the failed capacitor. Humidity-freeze cycling is optimized to break into moisture barriers. However, further studies will be required on additional module level power electronic (MLPE) devices to optimize the stress testing for condensation to precipitate any weakness to short circuiting and other humidity/bias failure modes.

Elimination of Drifts in Long-Duration Monitoring for Apnea-Hypopnea of Human Respiration.

PubMed

Jiang, Peng; Zhu, Rong

2016-10-25

This paper reports a methodology to eliminate an uncertain baseline drift in respiratory monitoring using a thermal airflow sensor exposed in a high humidity environment. Human respiratory airflow usually contains a large amount of moisture (relative humidity, RH > 85%). Water vapors in breathing air condense gradually on the surface of the sensor so as to form a thin water film that leads to a significant sensor drift in long-duration respiratory monitoring. The water film is formed by a combination of condensation and evaporation, and therefore the behavior of the humidity drift is complicated. Fortunately, the exhale and inhale responses of the sensor exhibit distinguishing features that are different from the humidity drift. Using a wavelet analysis method, we removed the baseline drift of the sensor and successfully recovered the respiratory waveform. Finally, we extracted apnea-hypopnea events from the respiratory signals monitored in whole-night sleeps of patients and compared them with golden standard polysomnography (PSG) results.

Overview of the International Space Station System Level Trace Contaminant Injection Test

NASA Technical Reports Server (NTRS)

Tatara, James D.; Perry, Jay L.; Franks, Gerald D.

1997-01-01

Trace contaminant control onboard the International Space Station will be accomplished not only by the Trace Contaminant Control Subassembly but also by other Environmental Control and Life Support System subassemblies. These additional removal routes include absorption by humidity condensate in the Temperature and Humidity Control Condensing Heat Exchanger and adsorption by the Carbon Dioxide Removal Assembly. The Trace Contaminant Injection Test, which was performed at NASA's Marshall Space Flight Center, investigated the system-level removal of trace contaminants by the International Space Station Atmosphere Revitalization, and Temperature/Humidity Control Subsystems, (November-December 1997). It is a follow-on to the Integrated Atmosphere Revitalization Test conducted in 1996. An estimate for the magnitude of the assisting role provided by the Carbon Dioxide Removal Assembly and the Temperature and Humidity Control unit was obtained. In addition, data on the purity of Carbon Dioxide Removal Assembly carbon dioxide product were obtained to support Environmental Control and Life Support System Air Revitalization Subsystem loop closure.

Elimination of Drifts in Long-Duration Monitoring for Apnea-Hypopnea of Human Respiration

PubMed Central

Jiang, Peng; Zhu, Rong

2016-01-01

This paper reports a methodology to eliminate an uncertain baseline drift in respiratory monitoring using a thermal airflow sensor exposed in a high humidity environment. Human respiratory airflow usually contains a large amount of moisture (relative humidity, RH > 85%). Water vapors in breathing air condense gradually on the surface of the sensor so as to form a thin water film that leads to a significant sensor drift in long-duration respiratory monitoring. The water film is formed by a combination of condensation and evaporation, and therefore the behavior of the humidity drift is complicated. Fortunately, the exhale and inhale responses of the sensor exhibit distinguishing features that are different from the humidity drift. Using a wavelet analysis method, we removed the baseline drift of the sensor and successfully recovered the respiratory waveform. Finally, we extracted apnea-hypopnea events from the respiratory signals monitored in whole-night sleeps of patients and compared them with golden standard polysomnography (PSG) results. PMID:27792151

Hydraulic fluids and jet engine oil: pyrolysis and aircraft air quality.

PubMed

van Netten, C; Leung, V

2001-01-01

Incidents of smoke in aircraft cabins often result from jet engine oil and/or hydraulic fluid that leaks into ventilation air, which can be subjected to temperatures that exceed 500 degrees C. Exposed flight-crew members have reported symptoms, including dizziness, nausea, disorientation, blurred vision, and tingling in the legs and arms. In this study, the authors investigated pyrolysis products of one jet engine oil and two hydraulic fluids at 525 degrees C. Engine oil was an important source of carbon monoxide. Volatile agents and organophosphate constituents were released from all the agents tested; however, the neurotoxin trimethyl propane phosphate was not found. The authors hypothesized that localized condensation of pyrolysis products in ventilation ducts, followed by mobilization when cabin heat demand was high, accounted for mid-flight incidents. The authors recommended that carbon monoxide data be logged continuously to capture levels during future incidents.

Plasma Methane Pyrolysis for Spacecraft Oxygen Loop Closure

NASA Technical Reports Server (NTRS)

Greenwood, Z. W.

2018-01-01

Life support is a critical function of any crewed space vehicle or habitat. Human life support systems on the International Space Station (ISS) include a number of atmosphere revitalization (AR) technologies to provide breathable air and a comfortable living environment to the crew. The Trace Contaminant Control System removes harmful volatile organic compounds and other trace contaminants from the circulating air. The Carbon Dioxide Removal Assembly (CDRA) removes metabolic carbon dioxide (CO2) and returns air to the cabin. Humidity is kept at comfortable levels by a number of condensing heat exchangers. The Oxygen Generation Assembly (OGA) electrolyzes water to produce oxygen for the crew and hydrogen (H2) as a byproduct. A Sabatier reaction-based CO2 Reduction Assembly (CRA) was launched to the ISS in 2009 and became fully operational in June 2011.The CRA interfaces with both the OGA and CDRA. Carbon dioxide from the CDRA is compressed and stored in tanks until hydrogen is available from OGA water electrolysis. When the OGA is operational and there is CO2 available, the CRA is activated and produces methane and water via the Sabatier reaction shown in Equation 1... One approach to achieve these higher recovery rates builds upon the ISS AR architecture and includes adding a methane post-processor to recover H2 from CRA methane. NASA has been developing the Plasma Pyrolysis Assembly (PPA) to fill the role of a methane post-processor.

The effect of coherent stirring on the advection–condensation of water vapour

PubMed Central

Vanneste, Jacques

2017-01-01

Atmospheric water vapour is an essential ingredient of weather and climate. The key features of its distribution can be represented by kinematic models which treat it as a passive scalar advected by a prescribed flow and reacting through condensation. Condensation acts as a sink that maintains specific humidity below a prescribed, space-dependent saturation value. To investigate how the interplay between large-scale advection, small-scale turbulence and condensation controls moisture distribution, we develop simple kinematic models which combine a single circulating flow with a Brownian-motion representation of turbulence. We first study the drying mechanism of a water-vapour anomaly released inside a vortex at an initial time. Next, we consider a cellular flow with a moisture source at a boundary. The statistically steady state attained shows features reminiscent of the Hadley cell such as boundary layers, a region of intense precipitation and a relative humidity minimum. Explicit results provide a detailed characterization of these features in the limit of strong flow. PMID:28690417

The effect of coherent stirring on the advection-condensation of water vapour

NASA Astrophysics Data System (ADS)

Tsang, Yue-Kin; Vanneste, Jacques

2017-06-01

Atmospheric water vapour is an essential ingredient of weather and climate. The key features of its distribution can be represented by kinematic models which treat it as a passive scalar advected by a prescribed flow and reacting through condensation. Condensation acts as a sink that maintains specific humidity below a prescribed, space-dependent saturation value. To investigate how the interplay between large-scale advection, small-scale turbulence and condensation controls moisture distribution, we develop simple kinematic models which combine a single circulating flow with a Brownian-motion representation of turbulence. We first study the drying mechanism of a water-vapour anomaly released inside a vortex at an initial time. Next, we consider a cellular flow with a moisture source at a boundary. The statistically steady state attained shows features reminiscent of the Hadley cell such as boundary layers, a region of intense precipitation and a relative humidity minimum. Explicit results provide a detailed characterization of these features in the limit of strong flow.

The effect of coherent stirring on the advection-condensation of water vapour.

PubMed

Tsang, Yue-Kin; Vanneste, Jacques

2017-06-01

Atmospheric water vapour is an essential ingredient of weather and climate. The key features of its distribution can be represented by kinematic models which treat it as a passive scalar advected by a prescribed flow and reacting through condensation. Condensation acts as a sink that maintains specific humidity below a prescribed, space-dependent saturation value. To investigate how the interplay between large-scale advection, small-scale turbulence and condensation controls moisture distribution, we develop simple kinematic models which combine a single circulating flow with a Brownian-motion representation of turbulence. We first study the drying mechanism of a water-vapour anomaly released inside a vortex at an initial time. Next, we consider a cellular flow with a moisture source at a boundary. The statistically steady state attained shows features reminiscent of the Hadley cell such as boundary layers, a region of intense precipitation and a relative humidity minimum. Explicit results provide a detailed characterization of these features in the limit of strong flow.

The performance of a mobile air conditioning system with a water cooled condenser

NASA Astrophysics Data System (ADS)

Di Battista, Davide; Cipollone, Roberto

2015-11-01

Vehicle technological evolution lived, in recent years, a strong acceleration due to the increased awareness of environmental issues related to pollutants and climate altering emissions. This resulted in a series of international regulations on automotive sector which put technical challenges that must consider the engine and the vehicle as a global system, in order to improve the overall efficiency of the system. The air conditioning system of the cabin, for instance, is the one of the most important auxiliaries in a vehicle and requires significant powers. Its performances can be significantly improved if it is integrated within the engine cooling circuit, eventually modified with more temperature levels. In this paper, the Authors present a mathematical model of the A/C system, starting from its single components: compressors, condenser, flush valve and evaporator and a comparison between different refrigerant fluid. In particular, it is introduced the opportunity to have an A/C condenser cooled by a water circuit instead of the external air linked to the vehicle speed, as in the actual traditional configuration. The A/C condenser, in fact, could be housed on a low temperature water circuit, reducing the condensing temperature of the refrigeration cycle with a considerable efficiency increase.

On the determination of the thermal comfort conditions of a metropolitan city underground railway.

PubMed

Katavoutas, George; Assimakopoulos, Margarita N; Asimakopoulos, Dimosthenis N

2016-10-01

Although the indoor thermal comfort concept has received increasing research attention, the vast majority of published work has been focused on the building environment, such as offices, residential and non-residential buildings. The present study aims to investigate the thermal comfort conditions in the unique and complex underground railway environment. Field measurements of air temperature, air humidity, air velocity, globe temperature and the number of passengers were conducted in the modern underground railway of Athens, Greece. Environmental monitoring was performed in the interior of two types of trains (air-conditioned and forced air ventilation cabins) and on selected platforms during the summer period. The thermal comfort was estimated using the PMV (predicted mean vote) and the PPD (predicted percentage dissatisfied) scales. The results reveal that the recommended thermal comfort requirements, although at relatively low percentages are met only in air-conditioned cabins. It is found that only 33% of the PPD values in air-conditioned cabins can be classified in the less restrictive comfort class C, as proposed by ISO-7730. The thermal environment is "slightly warm" in air-conditioned cabins and "warm" in forced air ventilation cabins. In addition, differences of the thermal comfort conditions on the platforms are shown to be associated with the depth and the design characteristics of the stations. The average PMV at the station with small depth is 0.9 scale points higher than that of the station with great depth. The number of passengers who are waiting at the platforms during daytime reveals a U-shaped pattern for a deep level station and an inverted course of PMV for a small depth station. Further, preliminary observations are made on the distribution of air velocity on the platforms and on the impact of air velocity on the thermal comfort conditions. Copyright © 2016 Elsevier B.V. All rights reserved.

Multi-channel fiber optic dew and humidity sensor

NASA Astrophysics Data System (ADS)

Limodehi, Hamid E.; Mozafari, Morteza; Amiri, Hesam; Légaré, François

2018-03-01

In this article, we introduce a multi-channel fiber optic dew and humidity sensor which works using a novel method based on relation between surface plasmon resonance (SPR) and water vapor condensation. The proposed sensor can instantly detect moisture or dew formation through its fiber optic channels, separately situated in different places. It enables to simultaneously measure the ambient Relative Humidity (RH) and dew point temperature of several environments with accuracy of 5%.

A microwave resonance dew-point hygrometer

NASA Astrophysics Data System (ADS)

Underwood, R. J.; Cuccaro, R.; Bell, S.; Gavioso, R. M.; Madonna Ripa, D.; Stevens, M.; de Podesta, M.

2012-08-01

We report the first measurements of a quasi-spherical microwave resonator used as a dew-point hygrometer. In conventional dew-point hygrometers, the condensation of water from humid gas flowing over a mirror is detected optically, and the mirror surface is then temperature-controlled to yield a stable condensed layer. In our experiments we flowed moist air from a humidity generator through a quasi-spherical resonator and detected the onset of condensation by measuring the frequency ratio of selected microwave modes. We verified the basic operation of the device over the dew-point range 9.5-13.5 °C by comparison with calibrated chilled-mirror hygrometers. These tests indicate that the microwave method may allow a quantitative estimation of the volume and thickness of the water layer which is condensed on the inner surface of the resonator. The experiments reported here are preliminary due to the limited time available for the work, but show the potential of the method for detecting not only water but a variety of other liquid or solid condensates. The robust all-metal construction should make the device appropriate for use in industrial applications over a wide range of temperatures and pressures.

Humidity sensing properties of Al-doped zinc oxide coating films

NASA Astrophysics Data System (ADS)

Saidi, S. A.; Mamat, M. H.; Ismail, A. S.; Malek, M. F.; Yusoff, M. M.; Sin, N. D. Md.; Zoolfakar, A. S.; Khusaimi, Z.; Rusop, M.

2018-05-01

Humidity sensor was fabricated using Al-doped zinc oxide (ZnO) coating films through spin-coating at room temperature. The sensing mechanism was discussed based on their nanostructures, such as surface area and porous nanostructures. Surface area and water adsorption are an important component in the low humidity, while at high humidity, porous nanostructures and capillary condensation become important. The results showed that the sensitivity of the Al-doped ZnO coating improved compared to that of the Al-doped ZnO nanorod arrays, with values of 7.38 at 40% to 90%RH (Relative humidity). All these results indicated that Al-doped ZnO coating had high potential for humidity-sensor applications.

Mist and water condensation inside incubators reduce the efficacy of phototherapy.

PubMed

de Carvalho, Manoel; Torrao, Carolina Turano; Moreira, Maria Elisabeth Lopes

2011-03-01

To measure the irradiance in humidified incubator under three different overhead phototherapy devices. The effective irradiance of three phototherapy devices was assessed by taking a series of irradiance measurements in the illuminated field. Measurements were made with a fixed bandwidth broadband radiometer (380-530 nm). The distance between the light source and the radiometer was 35 cm for the daylight fluorescent lamp, 40 cm for the light emitting diode (LED) and 50 cm for the halogen phototherapy. A double-wall incubator was kept at 36°C and set at three different levels of humidity (60-70%, 80% and equal or above 90%). The irradiance under the overhead daylight fluorescent lamp phototherapy did not change with the increasing humidity. However, above 90% humidity, when water vapour inside the incubator was so saturated to the point of totally condensing in the incubator walls, the measured irradiance decreased 15% of the initial values with the blue LED phototherapy and 45% with the halogen spotlight phototherapy. Highly humidified incubators are frequently used to treat very low birthweight infants. Health professionals should be aware that mist and water condensation inside an incubator may significantly reduce the efficacy of treatment.

Effects of homogeneous condensation in compressible flows: Ludwieg-tube experiments and simulations

NASA Astrophysics Data System (ADS)

Luo, Xisheng; Lamanna, Grazia; Holten, A. P. C.; van Dongen, M. E. H.

Effects of homogeneous nucleation and subsequent droplet growth in compressible flows in humid nitrogen are investigated numerically and experimentally. A Ludwieg tube is employed to produce expansion flows. Corresponding to different configurations, three types of experiment are carried out in such a tube. First, the phase transition in a strong unsteady expansion wave is investigated to demonstrate the mutual interaction between the unsteady flow and the condensation process and also the formation of condensation-induced shock waves. The role of condensation-induced shocks in the gradual transition from a frozen initial structure to an equilibrium structure is explained. Second, the condensing flow in a slender supersonic nozzle G2 is considered. Particular attention is given to condensation-induced oscillations and to the transition from symmetrical mode-1 oscillations to asymmetrical mode-2 oscillations in a starting nozzle flow, as first observed by Adam & Schnerr. The transition is also found numerically, but the amplitude, frequency and transition time are not yet well predicted. Third, a sharp-edged obstacle is placed in the tube to generate a starting vortex. Condensation in the vortex is found. Owing to the release of latent heat of condensation, an increase in the pressure and temperature in the vortex core is observed. Condensation-induced shock waves are found, for a sufficiently high initial saturation ratio, which interact with the starting vortex, resulting in a very complex flow. As time proceeds, a subsonic or transonic free jet is formed downstream of the sharp-edged obstacle, which becomes oscillatory for a relatively high main-flow velocity and for a sufficiently high humidity.

Atmospheric profiles of Black Carbon at remote locations using light-weight airborne Aethalometers

NASA Astrophysics Data System (ADS)

Hansen, A. D.; Močnik, G.; Drinovec, L.; Lenarcic, M.

2012-12-01

While measurements of atmospheric aerosols are routinely performed at ground-level around the world, there is far less knowledge of their concentrations at altitude: yet this data is a crucial requirement for our understanding of the dispersion of pollutants of anthropogenic origin, with their associated effects on radiative forcing, cloud condensation, and other adverse phenomena. Black Carbon (BC) is a unique tracer for combustion emissions, and can be detected rapidly and with great sensitivity by filter-based optical methods. It has no non-combustion sources and is not transformed by atmospheric processes. Recent technical advances have developed light-weight miniaturized instruments which can be operated on light aircraft or carried aboard commercial passenger flights. From January to April 2012, a single-seat ultra-light aircraft flew around the world on a scientific, photographic and environmental-awareness mission. The flight track crossed all seven continents and all major oceans, with altitudes up to 8.9 km ASL. The aircraft carried a custom-developed high-sensitivity dual-wavelength light-weight Aethalometer, operating at 370 and 880 nm with special provision to compensate for the effects of changing pressure, temperature and humidity. The instrument recorded BC concentrations with high temporal resolution and sensitivity better than 5 ng/m3. We present examples of data from flight tracks over remote oceans, uninhabited land masses, and densely populated areas, analyzing the spectral dependence of absorption to infer the contributions to BC from fossil fuel vs. biomass combustion, and aggregating the data into vertical profiles. The regional and long range transport of BC may be investigated using back-trajectories. We have also operated miniature instruments in the passenger cabins of long-distance commercial aircraft. Since there are no combustion sources within the cabin, any BC in the ventilation air must necessarily have originated from the outside air near the tropopause at the operating altitude of 10 ~ 12 km. We shall compare some of these data with the data from the ultra-light aircraft at remote locations, albeit at lower altitudes. References http://www.cgsplus.si/portals/0/WGF/wglfPage.htm Science, 335 (6074), p. 1286, 16 March 2012

Thermodynamic and kinetic theory of nucleation, deliquescence and efflorescence transitions in the ensemble of droplets on soluble particles.

PubMed

Shchekin, Alexander K; Shabaev, Ilya V; Hellmuth, Olaf

2013-02-07

Thermodynamic and kinetic peculiarities of nucleation, deliquescence and efflorescence transitions in the ensemble of droplets formed on soluble condensation nuclei from a solvent vapor have been considered. The interplay of the effects of solubility and the size of condensation nuclei has been analyzed. Activation barriers for the deliquescence and phase transitions and for the reverse efflorescence transition have been determined as functions of the relative humidity of the vapor-gas atmosphere, initial size, and solubility of condensation nuclei. It has been demonstrated that, upon variations in the relative humidity of the atmosphere, the crossover in thermodynamically stable and unstable variables of the droplet state takes place. The physical meaning of stable and unstable variables has been clarified. The kinetic equations for establishing equilibrium and steady distributions of binary droplets have been solved. The specific times for relaxation, deliquescence and efflorescence transitions have been calculated.

Comparison of the constituents of two jet engine lubricating oils and their volatile pyrolytic degradation products.

PubMed

van Netten, C; Leung, V

2000-03-01

Leaking oil seals in jet engines, at locations prior to the compressor stage, can be a cause of smoke in the cabins of BAe-146 aircraft. Compressed combustion air is bled off to pressurize the cabin and to provide a source of fresh air. Bleed air is diverted from a location just prior to the combustion chamber at a temperature around 500 degrees C. To prevent oil breakdown products from entering the cabin air, catalytic converters have been used to clean the air. During an oil seal failure this device becomes overloaded and smoke is observed in the cabin. Some aircraft companies have removed the catalytic converters and claim an improvement in air quality. During an oil seal failure, however, the flight crew is potentially exposed to the thermal breakdown products of the engine oils. Because very little is known regarding the thermal breakdown products of jet engine lubrication oils, two commercially available oils were investigated under laboratory conditions at 525 degrees C to measure the release of CO, CO2,NO2, and HCN as well as volatiles which were analyzed using GC-Mass spectrometry in an attempt to see if the neurotoxic agents tricresyl phosphates (TCPs) and trimethyl propane phosphate (TMPP) would be present or formed. TMPP was not found in these experiments. Some CO2 was generated along with CO which reached levels in excess of 100 ppm. HCN and NO2 were not detected. GC compositions of the two bulk oils and their breakdown products were almost identical. The presence of TCPs was confirmed in the bulk oils and in the volatiles. Localized condensation in the ventilation ducts and filters in the air conditioning packs are likely the reason why the presence of TCPs has not been demonstrated in cabin air. It was recommended that this needed to be verified in aircraft.

In situ measurement of particulate number density and size distribution from an aircraft

NASA Technical Reports Server (NTRS)

Briehl, D.

1974-01-01

Commercial particulate measuring instruments were flown aboard the NASA Convair 990. A condensation nuclei monitor was utilized to measure particles larger than approximately 0.003 micrometers in diameter. A specially designed pressurization system was used with this counter so that the sample could be fed into the monitor at cabin altitude pressure. A near-forward light scattering counter was used to measure the number and size distribution particles in the size range from 0.5 to 5 micrometers and greater in diameter.

Flight prototype CO2 and humidity control system

NASA Technical Reports Server (NTRS)

Rudy, K. M.

1977-01-01

A regenerable CO2 and humidity control system is presently being developed for potential use on the space shuttle as an alternative to the baseline lithium hydroxide system. The system utilizes a sorbent material (designated HS-C) to adsorb CO2 and water vapor from the cabin atmosphere and desorb the CO2 and water vapor overboard when exposed to a space vacuum. Continuous operation is achieved by utilizing two beds which are alternately cycled between adsorption and desorption. A shuttle vehicle integration study showed that the HS-C system offers substantial weight advantages compared to the baseline shuttle orbiter expendable lithium hydroxide CO2 removal system for extended missions beyond the nominal design of four men for seven days. This study defined a system packaging envelope in the area presently occupied by the LiOH cartridges.

International Space Station USOS Crew Quarters Ventilation and Acoustic Design Implementation

NASA Technical Reports Server (NTRS)

Broyan, James Lee, Jr.

2009-01-01

The International Space Station (ISS) United States Operational Segment (USOS) has four permanent rack sized ISS Crew Quarters (CQ) providing a private crewmember space. The CQ uses Node 2 cabin air for ventilation/thermal cooling, as opposed to conditioned ducted air from the ISS Temperature Humidity Control System or the ISS fluid cooling loop connections. Consequently, CQ can only increase the air flow rate to reduce the temperature delta between the cabin and the CQ interior. However, increasing airflow causes increased acoustic noise so efficient airflow distribution is an important design parameter. The CQ utilized a two fan push-pull configuration to ensure fresh air at the crewmember s head position and reduce acoustic exposure. The CQ interior needs to be below Noise Curve 40 (NC-40). The CQ ventilation ducts are open to the significantly louder Node 2 cabin aisle way which required significantly acoustic mitigation controls. The design implementation of the CQ ventilation system and acoustic mitigation are very inter-related and require consideration of crew comfort balanced with use of interior habitable volume, accommodation of fan failures, and possible crew uses that impact ventilation and acoustic performance. This paper illustrates the types of model analysis, assumptions, vehicle interactions, and trade-offs required for CQ ventilation and acoustics. Additionally, on-orbit ventilation system performance and initial crew feedback is presented. This approach is applicable to any private enclosed space that the crew will occupy.

Analysis of a membrane-based condesate recovery heat exchanger (CRX)

NASA Technical Reports Server (NTRS)

Newbold, D.D.

1993-01-01

The development of a temperature and humidity control system that can remove heat and recover water vapor is key to the development of an Environmental Control and Life Support System (ECLSS). Large quantities of water vapor must be removed from air, and this operation has proven difficult in the absense of gravity. This paper presents the modeling results from a program to develop a novel membrane-based heat exchanger known as the condensate recovery heat exchanger (CRX). This device cools and dehumidifies humid air and simultaneously recovers water-vapor condensate. In this paper, the CRX is described and the results of an analysis of the heat- and mass-transfer characteristics of the device are given.

Source Contaminant Control for the Heat Melt Compactor

NASA Technical Reports Server (NTRS)

Roman, Monsi; Howard, David

2015-01-01

The Logistics Reduction and Repurposing project includes the heat melt compactor (HMC), a device that compacts waste containing plastic into a tile that will minimize volume, and may be used as materials for radiation shielding. During the process, a small purge gas stream is directed through the HMC chamber to transport out gasses and humidity released from the process. NASA Marshall Space Flight Center is tasked with developing and delivering a contamination control system to clean the purge gas prior to exhausting it back into the cabin for crew inhalation.

Virtual Design of a Four-Bed Molecular Sieve for Exploration

NASA Technical Reports Server (NTRS)

Giesy, T. J.; Coker, R. F.; O'Connor, B. F.; Knox, J. C.

2017-01-01

Aboard the International Space Station, CO2 is removed from the cabin atmosphere by a four-bed molecular sieve (4BMS) process called the Carbon Dioxide Removal Assembly (CDRA).1 This 4BMS process operates by passing the CO2-laden air through a desiccant bed to remove any humidity and then passing the dried air through a sorbent bed to remove the CO2. While one pair of beds is in use, the other pair is thermally regenerated to allow for continuous CO2 removal.

Environmental Control and Life Support System, Water Recovery System

NASA Technical Reports Server (NTRS)

2000-01-01

The Environmental Control and Life Support System (ECLSS) Group of the Flight Projects Directorate at the Marshall Space Flight Center (MSFC) is responsible for designing and building the life support systems that will provide the crew of the International Space Station (ISS) a comfortable environment in which to live and work. This is a close-up view of ECLSS Water Recovery System (WRS) racks. The MSFC's ECLSS Group overseas much of the development of the hardware that will allow a constant supply of clean water for four to six crewmembers aboard the ISS. The WRS provides clean water through the reclamation of wastewaters, including water obtained from the Space Shuttle's fuel cells, crewmember urine, used shower, handwash and oral hygiene water cabin humidity condensate, and Extravehicular Activity (EVA) wastes. The WRS is comprised of a Urine Processor Assembly (UPA), and a Water Processor Assembly (WPA). The UPA accepts and processes pretreated crewmember urine to allow it to be processed along with other wastewaters in the WPA, which removes free gas, organic, and nonorganic constituents before the water goes through a series of multifiltration beds for further purification. Product water quality is monitored primarily through conductivity measurements. Unacceptable water is sent back through the WPA for reprocessing. Clean water is sent to a storage tank. The water must meet stringent purity standards before consumption by the crew. The UPA provided by the MSFC and the WRA is provided by the prime contractor, Hamilton Sundstrand Space Systems, International (HSSSI) from Cornecticut.

Cold air systems: Sleeping giant

DOE Office of Scientific and Technical Information (OSTI.GOV)

MacCracken, C.D.

1994-04-01

This article describes how cold air systems help owners increase the profits from their buildings by reducing electric costs and improving indoor air quality through lower relative humidity levels. Cold air distribution involves energy savings, cost savings, space savings, greater comfort, cleaner air, thermal storage, tighter ducting, coil redesign, lower relative humidities, retrofitting, and improved indoor air quality (IAQ). It opens a door for architects, engineers, owners, builders, environmentalists, retrofitters, designers, occupants, and manufacturers. Three things have held up cold air's usage: multiple fan-powered boxes that ate up the energy savings of primary fans. Cold air room diffusers that providedmore » inadequate comfort. Condensation from ducts, boxes, and diffusers. Such problems have been largely eliminated through research and development by utilities and manufacturers. New cold air diffusers no longer need fan powered boxes. It has also been found that condensation is not a concern so long as the ducts are located in air conditioned space, such as drop ceilings or central risers, where relative humidity falls quickly during morning startup.« less

Case histories of building material problems caused by condensation at an enclosed swimming pool and an enclosed ice rink

DOE Office of Scientific and Technical Information (OSTI.GOV)

VanGeem, M.G.; Farahmandpour, K.; Gajda, J.

1999-07-01

Enclosed swimming pools and ice rinks in winter climates have the potential for high indoor relative humidities and cold building materials. These elements can contribute to condensation and premature deterioration of building materials. Case histories are provided for an enclosed swimming pool and an enclosed ice rink with condensation problems. An evaluation was performed after roof leaks were reported at a recently constructed indoor swimming pool in a Chicago suburb. After a preliminary inspection, it was evident that the reported leaks were related to building moisture problems rather than a roof leak. Exterior brick masonry exhibited heavy efflorescence in themore » area of the swimming pools, and water streaks were visible on the exterior walls below the eaves. The evaluation included laboratory testing, a visual inspection, field tests and measurements, and analyses for condensation potential. Results of the evaluation indicated the presence of condensed moisture as a direct cause of the observed water stains, and masonry efflorescence. Recommended corrective actions developed. A 54-year-old enclosed ice rink in New England was under investigation to determine the cause of a deteriorated wood deck roof. The building did not have dehumidification or air handling systems, and was heated only when occupied. The evaluation included visual inspection and analyses for condensation potential. Results of the evaluation indicated condensation within the wood decking and insulation during winter months, and high relative humidities that prohibited drying during the spring, summer, and fall. These conditions, over an extended number of years, resulted in decay of the wood decking.« less

Monitoring space shuttle air quality using the Jet Propulsion Laboratory electronic nose

NASA Technical Reports Server (NTRS)

Ryan, Margaret Amy; Zhou, Hanying; Buehler, Martin G.; Manatt, Kenneth S.; Mowrey, Victoria S.; Jackson, Shannon P.; Kisor, Adam K.; Shevade, Abhijit V.; Homer, Margie L.

2004-01-01

A miniature electronic nose (ENose) has been designed and built at the Jet Propulsion Laboratory (JPL), Pasadena, CA, and was designed to detect, identify, and quantify ten common contaminants and relative humidity changes. The sensing array includes 32 sensing films made from polymer carbon-black composites. Event identification and quantification were done using the Levenberg-Marquart nonlinear least squares method. After successful ground training, this ENose was used in a demonstration experiment aboard STS-95 (October-November, 1998), in which the ENose was operated continuously for six days and recorded the sensors' response to the air in the mid-deck. Air samples were collected daily and analyzed independently after the flight. Changes in shuttle-cabin humidity were detected and quantified by the JPL ENose; neither the ENose nor the air samples detected any of the contaminants on the target list. The device is microgravity insensitive.

Development of an Amine-based System for Combined Carbon Dioxide, Humidity, and Trace Contaminant Control

NASA Technical Reports Server (NTRS)

Nalette, Tim; Reiss, Julie; Filburn, Tom; Seery, Thomas; Smith, Fred; Perry, Jay

2005-01-01

A number of amine-based carbon dioxide (CO2) removal systems have been developed for atmosphere revitalization in closed loop life support systems. Most recently, Hamilton Sundstrand developed an amine-based sorbent, designated SA9T, possessing approximately 2-fold greater capacity compared to previous formulations. This new formulation has demonstrated applicability for controlling CO2 levels within vehicles and habitats as well as during extravehicular activity (EVA). System volume is competitive with existing technologies. Further enhancements in system performance can be realized by incorporating humidity and trace contaminant control functions within an amine-based atmosphere revitalization system. A 3-year effort to develop prototype hardware capable of removing CO2, H2O, and trace contaminants from a cabin atmosphere has been initiated. Progress pertaining to defining system requirements and identifying alternative amine formulations and substrates is presented.

Effect of salt on the glass transition of condensed tapioca starch systems.

PubMed

Chuang, Lillian; Panyoyai, Naksit; Shanks, Robert A; Kasapis, Stefan

2017-08-15

This work examines the effect of including hydrated NaCl and CaCl 2 (up to 6% w/w) on the physicochemical properties of condensed tapioca starch. Samples were prepared by hot pressing at 120°C to produce condensed systems that covered a range of moisture contents from 7.34% w/w (23% relative humidity) to 19.52% w/w (75% relative humidity). Tensile storage modulus and heat flow measurements were taken using DMA and MDSC, which were accompanied by FTIR, WAXD and ESEM. Increasing the salt level enhances the mechanical strength of starch in the glassy state and shifts the glass transition temperature to a higher value. Antiplasticising effects of NaCl and CaCl 2 on the non-phosphorylated tapioca starch are indistinguishable from each other. Observations are complemented by intensification of absorbance peaks in FTIR spectra and a systematic change in shape and intensity of diffraction patterns with increasing addition of salt consistent with interactions between added ions and macromolecule. Copyright © 2017. Published by Elsevier Ltd.

Analysis of MIR Condensate and Potable Water

NASA Technical Reports Server (NTRS)

Pierre, L. M.; Bobe, L.; Protasov, N. N.; Sauer, R. L.; Schultz, J. R.; Sinyak, Y. E.; Skuratov, V. M.

1999-01-01

Approximately fifty percent of the potable water supplied to the Russian cosmonauts, American astronauts, and other occupants of the current Russian Mir Space Station is produced by the direct recycle of water from humidity condensate. The remainder comes from ground supplied potable water that is delivered on a Progress resupply spacecraft, or processed fuel cell water transferred from the Shuttle. Reclamation of water for potable and hygiene purposes is considered essential for extended duration missions in order to avoid massive costs associated with resupplying water from the ground. The Joint U.S/Russian Phase 1 program provided the U.S. the first opportunity to evaluate the performance of water reclamation hardware in microgravity. During the Phase I program, the U.S. collected recycled water, stored water, and humidity condensate samples for chemical and microbial evaluation. This experiment was conducted to determine the potability of the water supplied on Mir, to assess the reliability of the water reclamation and distribution systems, and to aid in developing water quality monitoring standards for International Space Station.

Analysis of water from the Space Shuttle and Mir Space Station by ion chromatography and capillary electrophoresis

NASA Technical Reports Server (NTRS)

Orta, D.; Mudgett, P. D.; Ding, L.; Drybread, M.; Schultz, J. R.; Sauer, R. L.

1998-01-01

Drinking water and condensate samples collected from the US Space Shuttle and the Russian Mir Space Station are analyzed routinely at the NASA-Johnson Space Center as part of an ongoing effort to verify water quality and monitor the environment of the spacecraft. Water quality monitoring is particularly important for the Mir water supply because approximately half of the water consumed is recovered from humidity condensate. Drinking water on Shuttle is derived from the fuel cells. Because there is little equipment on board the spacecraft for monitoring the water quality, samples collected by the crew are transported to Earth on Shuttle or Soyuz vehicles, and analyzed exhaustively. As part of the test battery, anions and cations are measured by ion chromatography, and carboxylates and amines by capillary electrophoresis. Analytical data from Shuttle water samples collected before and after several missions, and Mir condensate and potable recovered water samples representing several recent missions are presented and discussed. Results show that Shuttle water is of distilled quality, and Mir recovered water contains various levels of minerals imparted during the recovery processes as designed. Organic ions are rarely detected in potable water samples, but were present in humidity condensate samples.

Using Ice Nucleating Particles to Enable Desublimation on Chilled Substrates

NASA Astrophysics Data System (ADS)

O'Brien, Julia; Failor, Kevin; Bisbano, Caitlin; Mulroe, Megan; Nath, Saurabh; Vinatzer, Boris; Boreyko, Jonathan

2017-11-01

On a subfreezing surface, nucleating embryos usually form as supercooled condensate that later freeze into ice, as opposed to desublimation. Ice nucleating particles (INPs) have been widely used to freeze existing water; however, nobody has studied how they might affect the initial mode of nucleation. Here, we show that INPs deposited on a substrate can switch the mode of embryo nucleation to desublimation, rather than supercooled condensation. Deposition was achieved by evaporating a water droplet containing INPs on a hydrophobic silicon wafer. A Peltier stage was used to cool the wafer down inside of a controlled humidity chamber, such that the desired set point temperature correlated with the dew point and onset of nucleation. Beneath a critical surface temperature, microscopy indicated that desublimation occurred on the circular patch of deposited INPs, compared to supercooled condensation outside the circle. The hydrophobic surface was then patterned with hydrophilic stripe arrays, which facilitated the deposition of stripes of INPs via the same evaporation method. The resulting array of desublimating ice stripes created dry zones free of condensation or frost in the intermediate areas, as the hygroscopic ice stripes served as overlapping humidity sinks.

FIRE_AX_UW_C131A

Atmospheric Science Data Center

2015-11-25

... Hot-Wire Hygrometer RMS Pressure Var Platinum Resistance Pyranometer Radiometer Reverse Flow Spatial ... Parameters:  Condensation Nuclei Dew/Frost Point Temperature Droplet Concentration Humidity Irradiance Liquid Water ...

THE MECHANISM OF AERIAL DISINFECTION BY GLYCOLS AND OTHER CHEMICAL AGENTS

PubMed Central

Puck, Theodore T.

1947-01-01

The effectiveness of any compound as an aerial germicide depends upon the extent of condensation of its vapor on air-suspended bacteria, and on the rate at which the resulting concentration of germicide can produce death of the microorganisms. The properties of any compound conducive to production of the highest rate of kill of air-borne microorganisms by means of the smallest possible concentration of germicide vapor, are as folows: (a) a low vapor pressure, but not lower than 0.001 mm. Hg at 25°C.; (b) high hygroscopicity; (c) toxicity for bacterial metabolism—a high degree of potency is not necessary although the killing action will be more efficient the higher the antibacterial activity of the compound employed. For any compound the killing action is always a direct function of the concentration of its vapor in the air. The maximum amount of a hygroscopic substance which can exist in the vapor state decreases as the relative humidity increases. Hence, at high relative humidities the bactericidal efficiency is lowest. At lower relative humidities the air can contain more vapor, and hence a greater effect is possible. At any relative humidity, the killing action is greater, the more closely the germicide vapor concentration approaches the saturation point. The presence of soluble compounds in droplets containing bacteria promotes more extensive condensation of the germicide than would otherwise occur, and so enhances its effectiveness. In the absence of such soluble substances, low atmospheric humidities may cause complete desiccation of a bacterial particle. Under these conditions its surface may become resistant to the condensation of the vapor, and thus prevent effective germicidal action. The influence of temperature changes on the killing efficiency maybe correctly deduced from a consideration of the effect of a rise in temperature on the vapor pressure of the germicide and on the rate of its bactericidal action in vitro. Equations are presented for estimating quantitatively the magnitude of some of the effects discussed. PMID:19871647

Estimating the HVAC energy consumption of plug-in electric vehicles

NASA Astrophysics Data System (ADS)

Kambly, Kiran R.; Bradley, Thomas H.

2014-08-01

Plug in electric vehicles are vehicles that use energy from the electric grid to provide tractive and accessory power to the vehicle. Due to the limited specific energy of energy storage systems, the energy requirements of heating, ventilation, and air conditioning (HVAC) systems for cabin conditioning can significantly reduce their range between charges. Factors such as local ambient temperature, local solar radiation, local humidity, length of the trip and thermal soak have been identified as primary drivers of cabin conditioning loads and therefore of vehicle range. The objective of this paper is to develop a detailed systems-level approach to connect HVAC technologies and usage conditions to consumer-centric metrics of vehicle performance including energy consumption and range. This includes consideration of stochastic and transient inputs to the HVAC energy consumption model including local weather, solar loads, driving behavior, charging behavior, and regional passenger fleet population. The resulting engineering toolset is used to determine the summation of and geographical distribution of energy consumption by HVAC systems in electric vehicles, and to identify regions of US where the distributions of electric vehicle range are particularly sensitive to climate.

Evaluation of Volatile Organic Compounds and Carbonyl Compounds Present in the Cabins of Newly Produced, Medium- and Large-Size Coaches in China

PubMed Central

Lu, Yan-Yang; Lin, Yi; Zhang, Han; Ding, Dongxiao; Sun, Xia; Huang, Qiansheng; Lin, Lifeng; Chen, Ya-Jie; Chi, Yu-Lang; Dong, Sijun

2016-01-01

An air-conditioned coach is an important form of transportation in modern motorized society; as a result, there is an increasing concern of in-vehicle air pollution. In this study, we aimed to identify and quantify the levels of volatile organic compounds (VOCs) and carbonyl compounds (CCs) in air samples collected from the cabins of newly produced, medium- and large-size coaches. Among the identified VOCs and CCs, toluene, ethylbenzene, xylene, formaldehyde, acetaldehyde, acrolein/acetone, and isovaleraldehyde were relatively abundant in the cabins. Time was found to affect the emissions of the contaminants in the coaches. Except for benzaldehyde, valeraldehyde and benzene, the highest in-vehicle concentrations of VOCs and CCs were observed on the 15th day after coming off the assembly line, and the concentrations exhibited an approximately inverted U-shaped pattern as a function of time. Interestingly, this study also showed that the interior temperature of the coaches significantly affected the VOCs emissions from the interior materials, whereas the levels of CCs were mainly influenced by the relative humidity within the coaches. In China, guidelines and regulations for the in-vehicle air quality assessment of the coaches have not yet been issued. The results of this study provide further understanding of the in-vehicle air quality of air-conditioned coaches and can be used in the development of both specific and general rules regarding medium- and large-size coaches. PMID:27314375

Solid amine development program

NASA Technical Reports Server (NTRS)

Lovell, J. S.

1973-01-01

A regenerable solid amine material to perform the functions of humidity control and CO2 removal for space shuttle type vehicle is reported. Both small scale and large scale testing have shown this material to be competitive, especially for the longer shuttle missions. However, it had been observed that the material off-gasses ammonia under certain conditions. This presents two concerns. The first, that the ammonia would contaminate the cabin atmosphere, and second, that the material is degrading with time. An extensive test program has shown HS-C to produce only trace quantities of atmospheric contaminants, and under normal extremes, to have no practical life limitation.

Method and apparatus for extracting water from air

DOEpatents

Spletzer, Barry L.

2001-01-01

The present invention provides a method and apparatus for extracting liquid water from moist air using minimal energy input. The method comprises compressing moist air under conditions that foster the condensation of liquid water (ideally isothermal to a humidity of 1.0, then adiabatic thereafter). The air can be decompressed under conditions that do not foster the vaporization of the condensate. The decompressed, dried air can be exchanged for a fresh charge of moist air and the process repeated. The liquid condensate can be removed for use. The apparatus can comprise a compression chamber having a variable internal volume. An intake port allows moist air into the compression chamber. An exhaust port allows dried air out of the compression chamber. A condensation device fosters condensation at the desired conditions. A condensate removal port allows liquid water to be removed.

Water vapour condensation in a partly closed structure. Comparison between results obtained with an inside wet or dry bottom wall

NASA Astrophysics Data System (ADS)

Batina, Jean; Peyrous, René

2018-04-01

We are interested in the determination of the more significant parameters acting on the water vapour condensation in a partly closed structure, submitted to external constraints (temperature and humidity), in view to recover the generated droplets as an additional source of potable water. External temperature variations, by inducing temperature differences between outside and inside of the structure, lead to convective movements and thermal variations inside this structure. Through an orifice, these movements permit a renewing of the humid inner air and can lead to the condensation of the water vapour initially contained in the inner air volume and/or on the walls. With the above hypotheses, and by using a numerical simulation [1] based on the ambient air characteristics and a finite volumes method, it appears that condensed water quantities are mainly depending on the boundary conditions imposed. These conditions are: 1) dimensions of the structure; 2) external temperature and relative hygrometry; 3) the phase φ (T/RH) linking thermal and hydrometric conditions; 4) the air renewing and its hygrometry for each phase; and 5) for each case, the fact that the inside bottom wall can be wet or dry. The resulting condensed water vapour quantities obtained, for the width section, point out clearly that they are very depending on this phase φ (T/RH) which appears as the more significant parameter and can be modified by the presence or not of a thin layer of water vapour on the inside bottom wall. Condensation phenomenon could be increased if φ could be optimized.

Cooling Properties of the Shuttle Advanced Crew Escape Spacesuit: Results of an Environmental Chamber Experiment

NASA Technical Reports Server (NTRS)

Hamilton, Douglas; Gillis, David; Bue, Grant; Son, Chan; Norcross, Jason; Kuznetz, Larry; Chapman, Kirt; Chhipwadia, Ketan; McBride, Tim

2008-01-01

The shuttle crew wears the Advanced Crew Escape Spacesuit (ACES) to protect themselves from cabin decompression and to support bail out during landing. ACES is cooled by a liquid-cooled garment (LCG) that interfaces to a heat exchanger that dumps heat into the cabin. The ACES outer layer is made of Gore-Tex(Registered TradeMark), permitting water vapor to escape while containing oxygen. The crew can only lose heat via insensible water losses and the LCG. Under nominal landing operations, the average cabin temperature rarely exceeds 75 F, which is adequate for the ACES to function. Problem A rescue shuttle will need to return 11 crew members if the previous mission suffers a thermal protection system failure, preventing it from returning safely to Earth. Initial analysis revealed that 11 crew members in the shuttle will increase cabin temperature at wheel stop above 80 F, which decreases the ACES ability to keep crew members cool. Air flow in the middeck of the shuttle is inhomogeneous and some ACES may experience much higher temperatures that could cause excessive thermal stress to crew members. Methods A ground study was conducted to measure the cooling efficiency of the ACES at 75 F, 85 F, and 95 F at 50% relative humidity. Test subjects representing 5, 50, and 95 percentile body habitus of the astronaut corps performed hand ergometry keeping their metabolic rate at 400, 600, and 800 BTU/hr for one hour. Core temperature was measured by rectal probe and skin, while inside and outside the suit. Environmental chamber wall and cooling unit inlet and outlet temperatures were measured using high-resolution thermistors ( 0.2 C). Conclusions Under these test conditions, the ACES was able to protect the core temperature of all test subjects, however thermal stress due to high insensible losses and skin temperature and skin heat flow may impact crew performance. Further research should be performed to understand the impact on cognitive performance.

Changes in ocular and nasal signs and symptoms among air crew in relation to air humidification on intercontinental flights.

PubMed

Norbäck, Dan; Lindgren, Torsten; Wieslander, Gunilla

2006-04-01

This study evaluates the influence of air humidification in aircraft on symptoms, tear-film stability, nasal patency, and peak expiratory flow. Commercial air crew (N=71) were given a medical examination during eight flights from Stockholm to Chicago and eight flights in the opposite direction. Examinations were done onboard one Boeing 767 aircraft equipped with an evaporation humidifier in the forward part of the cabin. The investigators followed the air crew, staying one night in Chicago and returning with the same crew. Four of the flights had the air humidification device active in-flight to Chicago and deactivated when returning to Stockholm. The other four flights had the inverse humidification sequence. The humidification sequence was randomized and double blind. Hygienic measurements were performed. The humidification increased the relative air humidity by 10% in the 1st row in business class, by 3% in the last row (39th row) in tourist class, and by 3% in the cockpit. Air humidification increased tear-film stability and nasal patency and decreased ocular, nasal, and dermal symptoms and headache. The mean concentration of viable bacteria [77-108 colony-forming units (cfu)/m(3)], viable molds (74-84 cfu/m(3)), and particulate matter (1-8 microg/m(3)) was low, both during the humidified and non-humidified flights. Relative air humidity is low (10-12%) during intercontinental flights and can be increased by the use of a ceramic evaporation humidifier, without any measurable increase of microorganisms in cabin air. Air humidification could increase passenger and crew comfort by increasing tear-film stability and nasal patency and reducing various symptoms.

ISS Expeditions 16 & 17: Chemical Analysis Results for Potable Water

NASA Technical Reports Server (NTRS)

Straub, John E., II; Plumlee, Debrah K.; Schultz, John R.

2009-01-01

During the twelve month span of Expeditions 16 and 17 beginning October of 2007, the chemical quality of the potable water onboard the International Space Station (ISS) was verified safe for crew consumption through the return and chemical analysis of water samples by the Water and Food Analytical Laboratory (WAFAL) at Johnson Space Center (JSC). Reclaimed cabin humidity condensate and Russian ground-supplied water were the principle sources of potable water and for the first time, European groundsupplied water was also available. Although water was transferred from Shuttle to ISS during Expeditions 16 and 17, no Shuttle potable water was consumed during this timeframe. A total of 12 potable water samples were collected using U.S. hardware during Expeditions 16 and 17 and returned on Shuttle flights 1E (STS122), 1JA (STS123), and 1J (STS124). The average sample volume was sufficient for complete chemical characterization to be performed. The results of JSC chemical analyses of these potable water samples are presented in this paper. The WAFAL also received potable water samples for analysis from the Russian side collected inflight with Russian hardware, as well as preflight samples of Rodnik potable water delivered to ISS on Russian Progress vehicles 28 to 30. Analytical results for these additional potable water samples are also reported and discussed herein. Although the potable water supplies available during Expeditions 16 and 17 were judged safe for crew consumption, a recent trending of elevated silver levels in the SVOZV water is a concern for longterm consumption and efforts are being made to lower these levels.

NASA Global Atmospheric Sampling Program (GASP) data report for tape VL0014

NASA Technical Reports Server (NTRS)

Briehl, D.; Dudzinski, T. J.; Liu, D. C.

1980-01-01

The data currently available from GASP, including flight routes and dates, instrumentation, data processing procedures, and data tape specifications are described. Measurements of atmospheric ozone, cabin ozine, carbon monoxide, water vapor, particles, clouds, condensation nuclei, filter samples and related meteorological and flight information obtained during 562 flights of aircraft N533PA, N4711U, N655PA, and VH-EBE from October 3, 1977 through January 5, 1978 are reported. Data representing tropopause pressures obtained from time and space interpolation of National Meteorological Center archived data for the dates of the flights are included.

Health and perception of cabin air quality among Swedish commercial airline crew.

PubMed

Lindgren, T; Norbäck, D

2005-01-01

Health symptoms and perception of cabin air quality (CAQ) among commercial cabin crew were studied as a function of personal risk factors, occupation, and work on intercontinental flights with exposure to environmental tobacco smoke (ETS). A standardized questionnaire (MM 040 NA) was mailed in February to March 1997 to all Stockholm airline crew on duty in a Scandinavian airline (n=1857), and to office workers from the same airline (n=218). During this time, smoking was allowed only on intercontinental flights. The participation rate was 81% (n=1513) by the airline crew, and 77% (n=168) by the office group. Statistical analysis was performed by multiple logistic regression analysis, controlling for age, gender, atopy, current smoking habits, and occupation. The most common symptoms among airline crew were: fatigue (21%), nasal symptoms (15%), eye irritation (11%), dry or flushed facial skin (12%), and dry/itchy skin on hands (12%). The most common complaint about CAQ was dry air (53%). Airline crew had more nasal, throat, and hand skin symptoms, than office workers did. Airline crew with a history of atopy had more nasal, throat, and dermal face and hand symptoms than other crew members did. Older airline crew members had more complaints of difficulty concentrating, but fewer complaints of dermal symptoms on the face and hands than younger crew members did. Female crew members reported more headaches than male crew members reported. Smoking was not associated with frequency of symptoms. Pilots had fewer complaints of most symptoms than other crew had. Airline crew that had been on an intercontinental flight in the week before the survey had more complaints of fatigue, heavy-headedness, and difficulty concentrating. Complaints of stuffy air and dry air were more common among airline crew than among office workers from the same airline. Female crew had more complaints of stuffy and dry air than male crew had. Older cabin crew had fewer complaints of dry air than younger crew had, and cabin crew with atopy had more complaints of dry air than other crew had. Current smokers had fewer complaints of stuffy air than non-smokers had. Airline crew that had been on a flight on which smoking was allowed in the week before the survey, had more complaints of stuffy air, dry air and passive smoking, than crew that had not been on such a flight in the preceding week had. Complaints on cabin air quality and health symptoms were common among commercial airline crew, and related to age, gender, atopy and type of work onboard. The hygienic measurements showed that the relative air humidity is very low on intercontinental flights, and particle levels are high on flights with passive smoking. This illustrates the need to improve the cabin air quality in commercial airlines. Such improvements could include better control of cabin temperature, air humidification, efficient air filtration with high efficiency particulate air filter (HEPA) filtration on all types of aircraft and sufficient air exchange rate in order to fulfil current ventilation standards.

Dehumidifying Heat Pipe

NASA Technical Reports Server (NTRS)

Khattar, Mukesh K.

1993-01-01

U-shaped heat pipe partly dehumidifies air leaving air conditioner. Fits readily in air-handling unit of conditioner. Evaporator and condenser sections of heat pipe consist of finned tubes in comb pattern. Each tube sealed at one end and joined to manifold at other. Sections connected by single pipe carrying vapor to condenser manifold and liquid to evaporator manifold. Simple on/off or proportional valve used to control flow of working fluid. Valve actuated by temperature/humidity sensor.

Development of a Test for Evaluation of the Hydrothermal Stability of Sorbents Used in Closed-Loop CO2 Removal Systems

NASA Technical Reports Server (NTRS)

Knox, James C.; Gauto, Hernando; Miller, Lee A.

2015-01-01

The International Space Station Carbon Dioxide Removal Assembly uses zeolite 5A molecular sieve material packed into beds for the capture of cabin CO2. The beds are cyclically heated to drive off the CO2 and restore the removal capacity. Over time, the sorbent material has been found to break down resulting in dust that restricts flow through the beds. Humidity adsorbed in the 5A zeolite when it is heated is a suspected cause of this sorbent degradation. To evaluate the impact of adsorbed water during thermal cycling, the Hydrothermal Stability Test was developed. The test configuration provides comparative side-by-side flow restriction data for two sorbent materials at specifically controlled humidity levels. While the initial focus of the testing is on 5A zeolite materials currently used on the ISS, the system will also be used to evaluate future candidate materials. This paper describes the approach, the test system, current results, and future testing.

The development and testing of a regenerable CO2 and humidity control system for Shuttle

NASA Technical Reports Server (NTRS)

Boehm, A. M.

1977-01-01

A regenerable CO2 and humidity control system is presently being developed for potential use on Shuttle as an alternate to the baseline lithium hydroxide (LiOH) system. The system utilizes a sorbent material (designated 'HS-C') to adsorb CO2 and water vapor from the cabin atmosphere and desorb the CO2 and water vapor overboard when exposed to a space vacuum. Continuous operation is achieved by utilizing two beds which are alternately cycled between adsorption and desorption. This paper presents the significant hardware development and test accomplishments of the past year. A half-size breadboard system utilizing a flight configuration canister was successfully performance tested in simulated Shuttle missions. A vacuum desorption test provided considerable insight into the desorption phenomena and allowed a significant reduction of the Shuttle vacuum duct size. The fabrication and testing of a flight prototype canister and flight prototype vacuum valves have proven the feasibility of these full-size, flight-weight components.

Dermatitis and aircrew.

PubMed

Leggat, Peter A; Smith, Derek R

2006-01-01

Dermatitis is a common problem both in the workplace and in the general community. Airline personnel represent a novel occupational group as they are also exposed to a wide range of potential chemical irritants and other aggravating factors, such as low relative humidity and airborne pollutants. Common skin irritants include dielectric fluids from electrodischarge machining, 'prepreg' materials and sealants in aircraft manufacture, kerosene and various jet-fuel components. Commercial jet fuel is a complex mixture of aliphatic and aromatic compounds, and there is potential for dermal exposure among refueling and maintenance crew. Low relative humidity appears to exacerbate dermatitis amongst aircrew, especially on longer flight durations. Pilots may also be exposed to additional skin irritants outside of the cabin environment, such as ethylene glycol, hydraulic fluid or jet fuel, all of which may be encountered during routine inspections of aircraft before and after flight. Given these factors, preventive measures must carefully consider the undoubted potential for contact with irritants and allergens, which may lead to dermatitis in airline personnel.

[Humidification and heating of anesthetic gases during pediatric anesthesia using the Cicero Anesthesia Workstation].

PubMed

Strauss, J M; Hausdörfer, J; Hagemann, H; Schröder, D

1992-09-01

A series of 52 infants underwent general or urological surgery; all were ventilated with the CICERO. Two different flows of fresh gas were used. In group I (n = 21) the fresh gas flow was set exactly at the level of the minute volume, representing a half-open, non-rebreathing system. In group II (n = 31) the fresh gas flow was adjusted to 10% of the required minute volume. Temperature and relative humidity of the inspired gas were measured continuously close to the tracheal tube. Anaesthesia was accomplished with 2 vol% isoflurane, 21-30 vol% oxygen in nitrous oxide. The results were compared with those achieved with our time-tested paediatric equipment, a SERVO 900D ventilator with a Fisher-Paykel humidifier (Group III, n = 35). Using a high fresh gas flow, no increase in relative humidity in the inspired gas could be detected. The values varied between 12% and 25% (group I). Reducing the flow of fresh gas as indicated above resulted in an increase in the relative humidity (group II). Over the evaluated period of 2 h, humidity increased slowly from an initial mean value of 20% to a maximum of something over 70%. Using the SERVO 900D ventilator combined with the Fisher-Paykel humidifier, humidity reached a value of greater 90% within 10 min after activation of the heated cascade. Humidity in the inspired gas should exceed 70% to avoid damage to infant airways. This will not be attained until after more than 2 h with unaided breathing systems, by when most operations performed on paediatric patients will already be over. Condensed water may aspirated by small infants. This potentially dangerous situation was only encountered in the CICERO circuit, and not in the system protected by the Fisher-Paykel cascade. Dry gases can result in thickened mucous and in obstruction of a small tracheal tube, which requires emergency reintubation. With artificial airways dry gases damage the ciliated epithelia of the trachea and cause loss of water and body heat. The temperature of the "cold" gases varied within a range of 21-33 degrees C and could not be adjusted by the anaesthetist. In the CICERO system, heating the gases at the valve only prevents mechanical failure caused by water condensation. In pediatric anaesthesia, variable heating and non-condensing humidity are essential. The dry and heated gases of the CICERO are not acceptable in the daily practice of paediatric anaesthesia.

Building America Case Study: Compact Buried Ducts in a Hot-Humid Climate House, Lady's Island, South Carolina

DOE Office of Scientific and Technical Information (OSTI.GOV)

2016-02-01

A system of compact, buried ducts provides a high-performance and cost-effective solution for delivering conditioned air throughout the building. This report outlines research activities that are expected to facilitate adoption of compact buried duct systems by builders. The results of this research would be scalable to many new house designs in most climates and markets, leading to wider industry acceptance and building code and energy program approval. The primary research question with buried ducts is potential condensation at the outer jacket of the duct insulation in humid climates during the cooling season. Current best practices for buried ducts rely onmore » encapsulating the insulated ducts with closed-cell spray polyurethane foam insulation to control condensation and improve air sealing. The encapsulated buried duct concept has been analyzed and shown to be effective in hot-humid climates. The purpose of this project is to develop an alternative buried duct system that performs effectively as ducts in conditioned space - durable, energy efficient, and cost-effective - in a hot-humid climate (IECC warm-humid climate zone 3A) with three goals that distinguish this project: 1) Evaluation of design criteria for buried ducts that use common materials and do not rely on encapsulation using spray foam or disrupt traditional work sequences, 2) Establishing design criteria for compact ducts and incorporate those with the buried duct criteria to further reduce energy losses and control installed costs, and 3) Developing HVAC design guidance for performing accurate heating and cooling load calculations for compact buried ducts.« less

Compact Buried Ducts in a Hot-Humid Climate House

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mallay, Dave

2016-01-07

"9A system of compact, buried ducts provides a high-performance and cost-effective solution for delivering conditioned air throughout the building. This report outlines research activities that are expected to facilitate adoption of compact buried duct systems by builders. The results of this research would be scalable to many new house designs in most climates and markets, leading to wider industry acceptance and building code and energy program approval. The primary research question with buried ducts is potential condensation at the outer jacket of the duct insulation in humid climates during the cooling season. Current best practices for buried ducts rely onmore » encapsulating the insulated ducts with closed-cell spray polyurethane foam insulation to control condensation and improve air sealing. The encapsulated buried duct concept has been analyzed and shown to be effective in hot-humid climates. The purpose of this project is to develop an alternative buried duct system that performs effectively as ducts in conditioned space - durable, energy efficient, and cost-effective - in a hot-humid climate (IECC warm-humid climate zone 3A) with three goals that distinguish this project: 1) Evaluation of design criteria for buried ducts that use common materials and do not rely on encapsulation using spray foam or disrupt traditional work sequences; 2) Establishing design criteria for compact ducts and incorporate those with the buried duct criteria to further reduce energy losses and control installed costs; 3) Developing HVAC design guidance for performing accurate heating and cooling load calculations for compact buried ducts.« less

Hygroscopic aerosol deposition in the human upper respiratory tract under various thermo-humidity conditions.

PubMed

Xi, Jinxiang; Kim, Jongwon; Si, Xiuhua A; Zhou, Yue

2013-01-01

The deposition of hygroscopic aerosols is highly complex in nature, which results from a cumulative effect of dynamic particle growth and the real-time size-specific deposition mechanisms. The objective of this study is to evaluate hygroscopic effects on the particle growth, transport, and deposition of nasally inhaled aerosols across a range of 0.2-2.5 μm in an adult image-based nose-throat model. Temperature and relative humidity fields were simulated using the LRN k-ω turbulence model and species transport model under a spectrum of thermo-humidity conditions. Particle growth and transport were simulated using a well validated Lagrangian tracking model coupled with a user-defined hygroscopic growth module. Results of this study indicate that the saturation level and initial particle size are the two major factors that determine the particle growth rate (d/d0), while the effect of inhalation flow rate is found to be not significant. An empirical correlation of condensation growth of nasally inhaled hygroscopic aerosols in adults has been developed based on a variety of thermo-humidity inhalation conditions. Significant elevated nasal depositions of hygroscopic aerosols could be induced by condensation growth for both sub-micrometer and small micrometer particulates. In particular, the deposition of initially 2.5 μm hygroscopic aerosols was observed to be 5-8 times that of inert particles under warm to hot saturated conditions. Results of this study have important implications in exposure assessment in hot humid environments, where much higher risks may be expected compared to normal conditions.

Impact of measurable physical phenomena on contact thermal comfort

NASA Astrophysics Data System (ADS)

Fojtlín, Miloš; Pokorný, Jan; Fišer, Jan; Toma, Róbert; Tuhovčák, Ján

Cabin HVAC (Heating Ventilation and Air-conditioning) systems have become an essential part of personal vehicles as demands for comfortable transport are still rising. In fact, 85 % of the car trips in Europe are shorter than 18 km and last only up to 30 minutes. Under such conditions, the HVAC unit cannot often ensure desired cabin environment and passengers are prone to experience thermal stress. For this reason, additional comfort systems, such as heated or ventilated seats, are available on the market. However, there is no straightforward method to evaluate thermal comfort at the contact surfaces nowadays. The aim of this work is to summarise information about heated and ventilated seats. These technologies use electrical heating and fan driven air to contact area in order to achieve enhanced comfort. It is also expected, that such measures may contribute to lower energy consumption. Yet, in real conditions it is almost impossible to measure the airflow through the ventilated seat directly. Therefore, there is a need for an approach that would correlate measurable physical phenomena with thermal comfort. For this reason, a method that exploits a measurement of temperatures and humidity at the contact area is proposed. Preliminary results that correlate comfort with measurable physical phenomena are demonstrated.

Glass formation and unusual hygroscopic growth of iodic acid solution droplets with relevance for iodine mediated particle formation in the marine boundary layer

NASA Astrophysics Data System (ADS)

Murray, B. J.; Haddrell, A. E.; Peppe, S.; Davies, J. F.; Reid, J. P.; O'Sullivan, D.; Price, H. C.; Kumar, R.; Saunders, R. W.; Plane, J. M. C.; Umo, N. S.; Wilson, T. W.

2012-09-01

Iodine oxide particles are known to nucleate in the marine boundary layer where gas phase molecular iodine and organoiodine species are produced by macroalgae. These ultra-fine particles may then grow through the condensation of other materials to sizes where they may serve as cloud condensation nuclei. There has been some debate over the chemical identity of the initially nucleated particles. In laboratory simulations, hygroscopic measurements have been used to infer that they are composed of insoluble I2O4, while elemental analysis of laboratory generated particles suggests soluble I2O5 or its hydrated form iodic acid, HIO3 (I2O5·H2O). In this paper we explore the response of super-micron sized aqueous iodic acid solution droplets to varying humidity using both Raman microscopy and single particle electrodynamic traps. These measurements reveal that the propensity of an iodic acid solution droplet to crystallise is negligible on drying to ~0% relative humidity (RH). On applying mechanical pressure to these droplets they shatter in a manner consistent with an ultra-viscous liquid or a brittle glass. Water retention in amorphous material at low RH is important for understanding the hygroscopic growth of aerosol particles and uptake of other condensable material. Subsequent water uptake between 10 and 20% RH causes their viscosity to reduce sufficiently that the cracked droplets flow and merge. The persistence of iodic acid solution in an amorphous state, rather than a crystalline state, suggests they will more readily accommodate other condensable material and are therefore more likely to grow to sizes where they may serve as cloud condensation nuclei. On increasing the humidity to ~90% the mass of the droplets only increases by ~20% with a corresponding increase in radius of only 6%, which is remarkably small for a highly soluble material. We suggest that the small growth factor of aqueous iodic acid solution droplets is consistent with the small aerosol growth factors observed in previous experiments.

Condenser-type diffusion denuders for the collection of sulfur dioxide in a cleanroom.

PubMed

Chang, In-Hyoung; Lee, Dong Soo; Ock, Soon-Ho

2003-02-01

High-efficiency condenser-type diffusion denuders of cylindrical and planar geometries are described. The film condensation of water vapor onto a cooled denuder surface can be used as a method for collecting water-soluble gases. By using SO(2) as the test gas, the planar design offers quantitative collection efficiency at air sampling rates up to 5 L min(-1). Coupled to ion chromatography, the limit of detection (LOD) for SO(2) is 0.014 ppbv with a 30-min successive analysis sequence. The method has been successfully applied to the analysis of temperature- and humidity-controlled cleanroom air.

Condensation of atmospheric moisture from tropical maritime air masses as a freshwater resource.

PubMed

Gerard, R D; Worzel, J L

1967-09-15

A method is proposed whereby potable water may be obtained by condensing moisture from the atmosphere in suitable seashore or island areas. Deep, cold, offshore seawater is used as a source of cold and is pumped to condensers set up on shore to intercept the flow of highly humid, tropical, maritime air masses. This air, when cooled, condenses moisture, which is conducted away and stored for use as a water supply. Windmill-driven generators would supply low-cost power for the operation. Side benefits are derived by using the nutritious deep water to support aquiculture in nearby lagoons or to enhance the productivity of the outfall area. Additional benefits are derived from the condenser as an air-conditioning device for nearby residents. The islands of the Caribbean are used as an example of a location in the trade-winds belt where nearly optimum conditions for the operation of this system can be found.

Effect of temperature and relative humidity during transportation on green coffee bean moisture content and ochratoxin A production.

PubMed

Palacios-Cabrera, Hector A; Menezes, Hilary C; Iamanaka, Beatriz T; Canepa, Frederico; Teixeira, Aldir A; Carvalhaes, Nelson; Santi, Domenico; Leme, Plinio T Z; Yotsuyanagi, Katumi; Taniwaki, Marta H

2007-01-01

Changes in temperature, relative humidity, and moisture content of green coffee beans were monitored during transportation of coffee from Brazil to Italy. Six containers (three conventional and three prototype) were stowed in three different places (hold, first floor, and deck) on the ship. Each prototype was located next to a conventional container. The moisture content of the coffee in the container located on the first floor was less affected by environmental variations (0.7%) than that in the hold and on the deck. Coffee located in the hold showed the highest variation in moisture content (3%); in addition, the container showed visible condensation. Coffee transported on the deck showed an intermediary variation in moisture (2%), and there was no visible condensation. The variation in coffee moisture content of the prototype containers was similar to that of the conventional ones, especially in the top layers of coffee bags (2 to 3%), while the increase in water activity was 0.70. This suggests that diffusion of moisture occurs very slowly inside the cargo and that there are thus sufficient time and conditions for fungal growth. The regions of the container near the wall and ceiling are susceptible to condensation since they are close to the headspace with its high relative humidity. Ochratoxin A production occurred in coffee located at the top of the container on the deck and in the wet bags from the hold (those found to be wet on opening the containers at the final destination).

Flow structure of natural dehumidification over a horizontal finned-tube

NASA Astrophysics Data System (ADS)

Hirbodi, Kamran; Yaghoubi, Mahmood

2016-08-01

In the present study, structure of water drops formation, growth, coalescence and departure over a horizontal finned-tube during natural dehumidification is investigated experimentally. Starting time of repelling the drops as well as heat transfer rate and the rate of dripping condensates in quasi-steady-state conditions are presented. Furthermore, cold airflow pattern around the horizontal finned-tube is visualized by using smoke generation scheme during natural dehumidification process. The finned-tube has a length of 300 mm, and inner and outer fin diameters, fin thickness and fin spacing are 25.4, 56, 0.4 and 2 mm, respectively. The tests are conducted in an insulated control room with dimensions of 5.8 m × 3 m × 4 m. Ambient air temperature, relative humidity and fin base temperature are selected from 25 to 35 °C, from 40 to 70 % and from 4 to 8 °C, respectively. Observations show that natural condensation from humid air over the test case is completely dropwise. Droplets only form on the edge of the fin and lateral fin surfaces remain almost dry. Dehumidification process over the tested finned-tube is divided into four stages; nucleation, formation, growth and departure of drops. It is also observed that the condensate inundation leaves the tube bottom in the form of droplets. Smoke visualization depicts that humid airflows downward around the cold finned-tube surface without noticeable turbulence and separation in the initial stages of dehumidification process. But the airflow has some disturbances in the intermediate stage and especially during drop departure on the edge of the fins.

Condensing Heat Exchanger Concept Developed for Space Systems

NASA Technical Reports Server (NTRS)

Hasan, Mohammad M.; Nayagam, Vedha

2005-01-01

The current system for moisture removal and humidity control for the space shuttles and the International Space Station uses a two-stage process. Water first condenses onto fins and is pulled through "slurper bars." These bars take in a two-phase mixture of air and water that is then separated by the rotary separator. A more efficient design would remove the water directly from the air without the need of an additional water separator downstream. For the Condensing Heat Exchanger for Space Systems (CHESS) project, researchers at the NASA Glenn Research Center in collaboration with NASA Johnson Space Center are designing a condensing heat exchanger that utilizes capillary forces to collect and remove water and that can operate in varying gravitational conditions including microgravity, lunar gravity, and Martian gravity.

Numerical modeling of particle generation from ozone reactions with human-worn clothing in indoor environments

NASA Astrophysics Data System (ADS)

Rai, Aakash C.; Lin, Chao-Hsin; Chen, Qingyan

2015-02-01

Ozone-terpene reactions are important sources of indoor ultrafine particles (UFPs), a potential health hazard for human beings. Humans themselves act as possible sites for ozone-initiated particle generation through reactions with squalene (a terpene) that is present in their skin, hair, and clothing. This investigation developed a numerical model to probe particle generation from ozone reactions with clothing worn by humans. The model was based on particle generation measured in an environmental chamber as well as physical formulations of particle nucleation, condensational growth, and deposition. In five out of the six test cases, the model was able to predict particle size distributions reasonably well. The failure in the remaining case demonstrated the fundamental limitations of nucleation models. The model that was developed was used to predict particle generation under various building and airliner cabin conditions. These predictions indicate that ozone reactions with human-worn clothing could be an important source of UFPs in densely occupied classrooms and airliner cabins. Those reactions could account for about 40% of the total UFPs measured on a Boeing 737-700 flight. The model predictions at this stage are indicative and should be improved further.

Surface freezing of water.

PubMed

Pérez-Díaz, J L; Álvarez-Valenzuela, M A; Rodríguez-Celis, F

2016-01-01

Freezing, melting, evaporation and condensation of water are essential ingredients for climate and eventually life on Earth. In the present work, we show how surface freezing of supercooled water in an open container is conditioned and triggered-exclusively-by humidity in air. Additionally, a change of phase is demonstrated to be triggered on the water surface forming surface ice crystals prior to freezing of bulk. The symmetry of the surface crystal, as well as the freezing point, depend on humidity, presenting at least three different types of surface crystals. Humidity triggers surface freezing as soon as it overpasses a defined value for a given temperature, generating a plurality of nucleation nodes. An evidence of simultaneous nucleation of surface ice crystals is also provided.

Considerations for Conducting Plant Research in Open Atmosphere Chambers on ISS

NASA Astrophysics Data System (ADS)

Wheeler, Raymond; Hummerick, Mary; Graham, Thomas; Dixit, Anirudha; Massa, Gioia

The access to spaceflight and now the International Space Station has provided plant researchers a laboratory that is in continuous freefall (near weightlessness). As veteran spaceflight investigators know too well, research in space is difficult to conduct and the experiments are often confounded by secondary events. An example of this is the distribution of water and gases in rooting systems in µ-gravity. Since the water does not settle to the ”bottom” of the rooting media in space, there can be poor distribution and movement of water and oxygen, which in turn can stress the plants. This also creates challenges for conducting ground controls where the logical approach is to use the same volume of water as in space. But under 1-g, the water does settle to the bottom of the root zone, which leaves less in the upper profile of the rooting medium. In addition, some chambers such as the Russian Svet (on Mir), Lada (ISS), and NASA’s Veggie chamber were or are open to the cabin air. This simplifies the hardware development and allows the use of cabin air for cooling and supplying CO2 to the plants. Yet it also exposes the plants to the cabin air, which could have very high CO2 levels (e.g., 3000 to 6000 ppm), low humidity, and trace contaminants that might be below the limits for human concerns but could still affect plants. A known effect of these “super-elevated” CO2 levels on many dicot species is increased transpiration due to elevated stomatal conductance, both during the light and the dark cycles. Examples of these secondary effects will be discussed, along with potential approaches for conducting adequate ground controls.

Nano-enabled paper humidity sensor for mobile based point-of-care lung function monitoring.

PubMed

Bhattacharjee, Mitradip; Nemade, Harshal B; Bandyopadhyay, Dipankar

2017-08-15

The frequency of breathing and peak flow rate of exhaled air are necessary parameters to detect chronic obstructive pulmonary diseases (COPDs) such as asthma, bronchitis, or pneumonia. We developed a lung function monitoring point-of-care-testing device (LFM-POCT) consisting of mouthpiece, paper-based humidity sensor, micro-heater, and real-time monitoring unit. Fabrication of a mouthpiece of optimal length ensured that the exhaled air was focused on the humidity-sensor. The resistive relative humidity sensor was developed using a filter paper coated with nanoparticles, which could easily follow the frequency and peak flow rate of the human breathing. Adsorption followed by condensation of the water molecules of the humid air on the paper-sensor during the forced exhalation reduced the electrical resistance of the sensor, which was converted to an electrical signal for sensing. A micro-heater composed of a copper-coil embedded in a polymer matrix helped in maintaining an optimal temperature on the sensor surface. Thus, water condensed on the sensor surface only during forcible breathing and the sensor recovered rapidly after the exhalation was complete by rapid desorption of water molecules from the sensor surface. Two types of real-time monitoring units were integrated into the device based on light emitting diodes (LEDs) and smart phones. The LED based unit displayed the diseased, critical, and fit conditions of the lungs by flashing LEDs of different colors. In comparison, for the mobile based monitoring unit, an application was developed employing an open source software, which established a wireless connectivity with the LFM-POCT device to perform the tests. Copyright © 2017 Elsevier B.V. All rights reserved.

Method for Qualification of Coatings Applied to Wet Surfaces

DOT National Transportation Integrated Search

2009-12-16

The field application of a pipeline repair or rehabilitation coating usually cannot wait until ambient conditions become optimal. In a humid environment, water can condense on the pipe surface because the pipe surface is usually cooler than the ambie...

Rough surface adhesion in the presence of capillary condensation

DOE PAGES

DelRio, Frank W.; Dunn, Martin L.; Phinney, Leslie M.; ...

2007-04-17

Capillary condensation of water can have a significant effect on rough surface adhesion. Here, to explore this phenomenon between micromachined surfaces, the authors perform microcantilever experiments as a function of surface roughness and relative humidity (RH). Below a threshold RH, the adhesion is mainly due to van der Waals forces across extensive noncontacting areas. Above the threshold RH, the adhesion jumps due to capillary condensation and increases towards the upper limit of Γ=144mJ/m 2. Lastly, a detailed model based on the measured surface topography qualitatively agrees with the experimental data only when the topographic correlations between the upper and lowermore » surfaces are considered.« less

Investigation of Condensing Ice Heat Exchangers for MTSA Technology Development

NASA Technical Reports Server (NTRS)

Padilla, Sebastian; Powers, Aaron; Ball, Tyler; Lacomini, Christie; Paul, Heather L.

2009-01-01

Metabolic heat regenerated Temperature Swing Adsorption (MTSA) technology is being developed for thermal, carbon dioxide (CO2) and humidity control for a Portable Life Support Subsystem (PLSS). Metabolically-produced CO2 present in the ventilation gas of a PLSS is collected using a CO2-selective adsorbent via temperature swing adsorption. The temperature swing is initiated through cooling to well below metabolic temperatures. Cooling is achieved with a sublimation heat exchanger using water or liquid carbon dioxide (L CO2) expanded below sublimation temperature when exposed to low pressure or vacuum. Subsequent super heated vapor, as well as additional coolant, is used to further cool the astronaut. The temperature swing on the adsorbent is then completed by warming the adsorbent with a separate condensing ice heat exchanger (CIHX) using metabolic heat from moist ventilation gas. The condensed humidity in the ventilation gas is recycled at the habitat. The water condensation from the ventilation gas represents a significant source of potential energy for the warming of the adsorbent bed as it represents as much as half of the energy potential in the moist ventilation gas. Designing a heat exchanger to efficiently transfer this energy to the adsorbent bed and allow the collection of the water is a challenge since the CIHX will operate in a temperature range from 210K to 280K. The ventilation gas moisture will first freeze and then thaw, sometimes existing in three phases simultaneously.

Product study of oleic acid ozonolysis as function of humidity

NASA Astrophysics Data System (ADS)

Vesna, O.; Sax, M.; Kalberer, M.; Gaschen, A.; Ammann, M.

The heterogeneous reaction of ozone with oleic acid (OA) aerosol particles was studied as function of humidity and reaction time in an aerosol flow reactor using an off-line gas chromatography mass spectrometry (GC-MS) technique. We report quantitative yields of the major C9 ozonolysis products in both gas and condensed phases and the effect of relative humidity on the product distribution. The measurements were carried out with OA aerosol particles at room temperature. The results indicate that the product yields are increasing with increasing relative humidity during the reaction. Nonanal (NN) was detected as the major gas-phase product (55.6 ± 2.3%), with 94.5 ± 2.4% of the NN yield in the gas, and 5.5 ± 2.7% in the particulate phase, whereas nonanoic, oxononanoic and azelaic acids were detected exclusively in the particulate phase. Using UV-spectrometry, we observed that peroxides make up the largest fraction of products, about half of the product aerosol mass, and their concentration decreased with increasing humidity.

Mass and heat transfer model of Tubular Solar Still

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ahsan, Amimul; Fukuhara, Teruyuki

2010-07-15

In this paper, a new mass and heat transfer model of a Tubular Solar Still (TSS) was proposed incorporating various mass and heat transfer coefficients taking account of the humid air properties inside the still. The heat balance of the humid air and the mass balance of the water vapor in the humid air were formulized for the first time. As a result, the proposed model enabled to calculate the diurnal variations of the temperature, water vapor density and relative humidity of the humid air, and to predict the hourly condensation flux besides the temperatures of the water, cover andmore » trough, and the hourly evaporation flux. The validity of the proposed model was verified using the field experimental results carried out in Fukui, Japan and Muscat, Oman in 2008. The diurnal variations of the calculated temperatures and water vapor densities had a good agreement with the observed ones. Furthermore, the proposed model can predict the daily and hourly production flux precisely. (author)« less

Phosphorylation and ubiquitination-dependent degradation of CABIN1 releases p53 for transactivation upon genotoxic stress.

PubMed

Choi, Soo-Youn; Jang, Hyonchol; Roe, Jae-Seok; Kim, Seong-Tae; Cho, Eun-Jung; Youn, Hong-Duk

2013-02-01

CABIN1 acts as a negative regulator of p53 by keeping p53 in an inactive state on chromatin. Genotoxic stress causes rapid dissociation of CABIN1 and activation of p53. However, its molecular mechanism is still unknown. Here, we reveal the phosphorylation- and ubiquitination-dependent degradation of CABIN1 upon DNA damage, releasing p53 for transcriptional activation. The DNA-damage-signaling kinases, ATM and CHK2, phosphorylate CABIN1 and increase the degradation of CABIN1 protein. Knockdown or overexpression of these kinases influences the stability of CABIN1 protein showing that their activity is critical for degradation of CABIN1. Additionally, CABIN1 was found to undergo ubiquitin-dependent proteasomal degradation mediated by the CRL4DDB2 ubiquitin ligase complex. Both phosphorylation and ubiquitination of CABIN1 appear to be relevant for controlling the level of CABIN1 protein upon genotoxic stress.

The Fungus among Us.

ERIC Educational Resources Information Center

Weidner, Robert H.

2003-01-01

Offers tips for fighting mold in schools, asserting that it can contribute significantly to poor indoor air quality and sick building syndrome. Offers an overview on mold and discusses the steps of: humidity control, building inspections, condensation control or removal, and floor and carpet cleaning. (EV)

Total Thermal Management of Battery Electric Vehicles (BEVs)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lustbader, Jason A; Rugh, John P; Winkler, Jonathan M

The key hurdles to achieving wide consumer acceptance of battery electric vehicles (BEVs) are weather-dependent drive range, higher cost, and limited battery life. These translate into a strong need to reduce a significant energy drain and resulting drive range loss due to auxiliary electrical loads the predominant of which is the cabin thermal management load. Studies have shown that thermal subsystem loads can reduce the drive range by as much as 45% under ambient temperatures below -10 degrees C. Often, cabin heating relies purely on positive temperature coefficient (PTC) resistive heating, contributing to a significant range loss. Reducing this rangemore » loss may improve consumer acceptance of BEVs. The authors present a unified thermal management system (UTEMPRA) that satisfies diverse thermal and design needs of the auxiliary loads in BEVs. Demonstrated on a 2015 Fiat 500e BEV, this system integrates a semi-hermetic refrigeration loop with a coolant network and serves three functions: (1) heating and/or cooling vehicle traction components (battery, power electronics, and motor) (2) heating and cooling of the cabin, and (3) waste energy harvesting and re-use. The modes of operation allow a heat pump and air conditioning system to function without reversing the refrigeration cycle to improve thermal efficiency. The refrigeration loop consists of an electric compressor, a thermal expansion valve, a coolant-cooled condenser, and a chiller, the latter two exchanging heat with hot and cold coolant streams that may be directed to various components of the thermal system. The coolant-based heat distribution is adaptable and saves significant amounts of refrigerant per vehicle. Also, a coolant-based system reduces refrigerant emissions by requiring fewer refrigerant pipe joints. The authors present bench-level test data and simulation analysis and describe a preliminary control scheme for this system.« less

Freeing Water from Viruses and Bacteria

NASA Technical Reports Server (NTRS)

2004-01-01

Four years ago, Argonide Corporation, a company focused on the research, production, and marketing of specialty nano materials, was seeking to develop applications for its NanoCeram[R] fibers. Only 2 nanometers in diameter, these nano aluminum oxide fibers possessed unusual bio-adhesive properties. When formulated into a filter material, the electropositive fibers attracted and retained electro-negative particles such as bacteria and viruses in water-based solutions. This technology caught the interest of NASA as a possible solution for improved water filtration in space cabins. NASA's Johnson Space Center awarded Sanford, Florida-based Argonide a Phase I Small Business Innovation Research (SBIR) contract to determine the feasibility of using the company's filter for purifying recycled space cabin water. Since viruses and bacteria can be carried aboard space cabins by space crews, the ability to detect and remove these harmful substances is a concern for NASA. The Space Agency also desired an improved filter to polish the effluent from condensed and waste water, producing potable drinking water. During its Phase I partnership with NASA, Argonide developed a laboratory-size filter capable of removing greater than 99.9999 percent of bacteria and viruses from water at flow rates more than 200 times faster than virus-rated membranes that remove particles by sieving. Since the new filter s pore size is rather large compared to other membranes, it is also less susceptible to clogging by small particles. In September 2002, Argonide began a Phase II SBIR project with Johnson to develop a full-size cartridge capable of serving a full space crew. This effort, which is still ongoing, enabled the company to demonstrate that its filter media is an efficient absorbent for DNA and RNA.

Photochemistry of Glyoxal in Wet Aerosols: Smog Chamber Study

NASA Astrophysics Data System (ADS)

Lim, Y. B.; Kim, H.; Turpin, B. J.

2015-12-01

Aqueous chemistry is an important pathway for the formation of secondary organic aerosol (SOA). Reaction vessel studies provide evidence that in the aqueous phase photooxidation of water soluble organic compounds (e.g., glyoxal, methylglyoxal) form multifunctional organic products and oligomers. In this work, we extend this bulk-phase chemistry to the condensed-phase chemistry that occurs in/on aerosols by conducting smog chamber experiments — photooxidation of ammonium sulfate and sulfuric acid aerosols containing glyoxal and hydrogen peroxide in the presence of NOx under dry/humid conditions. Particles were analyzed using ultra performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS). In the irradiated chamber, photooxidation products of glyoxal as seen in reaction vessel experiments (e.g., oxalic acids and tartaric acids) were also formed in both ammonium sulfate aerosols and sulfuric acid aerosols at humid and even dry conditions. However, the major products were organosulfurs (CHOS), organonitrogens (CHON), and nitrooxy-organosulfates (CHONS), which were also dominantly formed in the dark chamber. These products were formed via non-radical reactions, which depend on acidity and humidity. However, the real-time profiles in the dark chamber and the irradiated chamber were very different, suggesting photochemistry substantially affects non-radical formation in the condensed phase.

Low-noise humidity controller for imaging water mediated processes in atomic force microscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gaponenko, I., E-mail: iaroslav.gaponenko@unige.ch; Gamperle, L.; Herberg, K.

2016-06-15

We demonstrate the construction of a novel low-noise continuous flow humidity controller and its integration with a commercial variable-temperature atomic force microscope fluid cell, allowing precise control of humidity and temperature at the sample during nanoscale measurements. Based on wet and dry gas mixing, the design allows a high mechanical stability to be achieved by means of an ultrasonic atomiser for the generation of water-saturated gas, improving upon previous bubbler-based architectures. Water content in the flow is measured both at the inflow and outflow of the fluid cell, enabling the monitoring of water condensation and icing, and allowing controlled variationmore » of the sample temperature independently of the humidity. To benchmark the performance of the controller, the results of detailed noise studies and time-based imaging of the formation of ice layers on highly oriented pyrolytic graphite are shown.« less

Deterioration of building materials in Roman catacombs: the influence of visitors.

PubMed

Sanchez-Moral, S; Luque, L; Cuezva, S; Soler, V; Benavente, D; Laiz, L; Gonzalez, J M; Saiz-Jimenez, C

2005-10-15

In the last decades, damages on building materials and mural paintings were observed in Roman catacombs. The damages were due to extensive formation of biofilms induced by artificial illumination and humidity. Microenvironmental data (temperature, CO(2) concentration, humidity, and atmospheric pressure) clearly showed the negative influence of visitors. Increasing heat, light and water vapour condensation into corridors and cubicles favoured biofilm development. The composition of biofilms was different and depended mainly on distance to illumination sources and humidity, thus denoting the influence of light on the growth of phototrophic microorganisms in the catacombs. In addition, biofilm distribution was governed by the type of material to be colonised. This study shows that countermeasures are needed to prevent deterioration of hypogean environments.

Indoor to outdoor air quality associations with self-pollution implications inside passenger car cabins

NASA Astrophysics Data System (ADS)

Abi-Esber, L.; El-Fadel, M.

2013-12-01

In this study, in-vehicle and out-vehicle concentrations of fine particulate matter (PM2.5) and carbon monoxide (CO) are measured to assess commuter's exposure in a commercial residential area and on a highway, under three popular ventilation modes namely, one window half opened, air conditioning on fresh air intake, and air conditioning on recirculation and examine its relationship to scarcely studied parameters including self pollution, out-vehicle sample intake location and meteorological gradients. Self pollution is the intrusion of a vehicle's own engine fumes into the passenger's compartment. For this purpose, six car makes with different ages were instrumented to concomitantly monitor in- and out-vehicle PM2.5 and CO concentrations as well as meteorological parameters. Air pollution levels were unexpectedly higher in new cars compared to old cars, with in-cabin air quality most correlated to that of out-vehicle air near the front windshield. Self-pollution was observed at variable rates in three of the six tested cars. Significant correlations were identified between indoor to outdoor pressure difference and PM2.5 and CO In/Out (IO) ratios under air recirculation and window half opened ventilation modes whereas temperature and humidity difference affected CO IO ratios only under the air recirculation ventilation mode.

Dynamics of water condensation over arrays of hydrophilic patches

NASA Astrophysics Data System (ADS)

Seco-Gudiña, R.; Guadarrama-Cetina, J.; González-Viñas, W.

2017-04-01

We report experimental results of drop-wise condensation on a wettability patterned substrate. It consists of a 2-d array of hydrophilic patches/spots on a macroscopically hydrophobic surface. We show that in this kind of system, there is not a relevant humidity sink, but the scale and the closeness of the different patches/spots affect the mechanisms which are important during the experiment. These results may provide clues to obtain higher dew yields in arid or semi-arid regions as a way to obtain potable water.

Fast, high sensitivity dewpoint hygrometer

NASA Technical Reports Server (NTRS)

Hoenk, Michael E. (Inventor)

1998-01-01

A dewpoint/frostpoint hygrometer that uses a surface moisture-sensitive sensor as part of an RF oscillator circuit with feedback control of the sensor temperature to maintain equilibrium at the sensor surface between ambient water vapor and condensed water/ice. The invention is preferably implemented using a surface acoustic wave (SAW) device in an RF oscillator circuit configured to generate a condensation-dependent output signal, a temperature sensor to measure the temperature of the SAW device and to distinguish between condensation-dependent and temperature-dependent signals, a temperature regulating device to control the temperature of the SAW device, and a feedback control system configured to keep the condensation-dependent signal nearly constant over time in the presence of time-varying humidity, corrected for temperature. The effect of this response is to heat or cool the surface moisture-sensitive device, which shifts the equilibrium with respect to evaporation and condensation at the surface of the device. The equilibrium temperature under feedback control is a measure of dewpoint or frostpoint.

2. WILLIAM ELLIOT CABIN AND OUTBULIDING, CABIN WEST REAR AND ...

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

2. WILLIAM ELLIOT CABIN AND OUTBULIDING, CABIN WEST REAR AND NORTH SIDES, OUTBULIDING WEST FRONT AND NORTH SIDE - Liberty Historic District, William Elliot Cabin, Route 2, Cle Elum, Liberty, Kittitas County, WA

1. WILLIAM ELLIOT CABIN AND OUTBUILDING, CABIN EAST FRONT AND ...

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

1. WILLIAM ELLIOT CABIN AND OUTBUILDING, CABIN EAST FRONT AND SOUTH SIDE, OUTBUILDING EAST REAR AND SOUTH SIDES - Liberty Historic District, William Elliot Cabin, Route 2, Cle Elum, Liberty, Kittitas County, WA

Prediction of car cabin environment by means of 1D and 3D cabin model

NASA Astrophysics Data System (ADS)

Fišer, J.; Pokorný, J.; Jícha, M.

2012-04-01

Thermal comfort and also reduction of energy requirements of air-conditioning system in vehicle cabins are currently very intensively investigated and up-to-date issues. The article deals with two approaches of modelling of car cabin environment; the first model was created in simulation language Modelica (typical 1D approach without cabin geometry) and the second one was created in specialized software Theseus-FE (3D approach with cabin geometry). Performance and capabilities of this tools are demonstrated on the example of the car cabin and the results from simulations are compared with the results from the real car cabin climate chamber measurements.

Monitoring of Air Quality in Passenger Cabins of the Athens Metro

NASA Astrophysics Data System (ADS)

Tsairidi, Evangelia; Assimakopoulos, Vasiliki D.; Assimakopoulos, Margarita-Niki; Barbaresos, Nicolaos; Karagiannis, Athanassios

2013-04-01

The air pollution induced by various transportation means combines the emission of pollutants with the simultaneous presence of people. In this respect, the scientific community has focused its efforts in studying both the air quality within busy streets and inside cars, buses and the underground railway network in order to identify the pollutants' sources and levels as well as the human exposure. The impact of the air pollution on commuters of the underground may be more severe because it is a confined space, extended mostly under heavily trafficked urban streets, relies on mechanical ventilation for air renewal and gathers big numbers of passengers. The purpose of the present work is to monitor the air quality of the city of Athens Metro Network cabins and platforms during the unusually hot summer of 2012. For that cause particulate matter (PM10, PM2.5, PM1), carbon dioxide (CO2), the number of commuters along with temperature (T) and humidity (RH) were recorded inside the Athens Metro Blue Line trains (covering a route from the centre of Athens (Aigaleo) to the Athens International Airport) and on the platforms of a central (Syntagma) and a suburban-traffic (Doukissis Plakentias) station between June and August. The data collection included six different experiments that took place for 2 consecutive working days each, for a time period of 6 weeks from 6:30 am too 7:00 pm in order to account for different outdoor climatic conditions and for morning and evening rush hours respectively. Measurements were taken in the middle car of the moving trains and the platform end of the selected stations. The results show PM concentrations to be higher (approximately 2 to 5 times) inside the cabins and o the platforms of the underground network as compared to the outdoor levels monitored routinely by the Ministry of Environment. Moreover, PM1, PM2.5 and PM10 average concentrations recorded at the Syntagma Station Platform were almost constantly higher reaching 11 μg m-3 47 μg m-3 and 246 μg m-3 respectively on July 11th, as opposed to the ones at Doukissis Plakentias (4 μg m-3, 15 μg m-3and 97 μg m-3 respectively). Interestingly enough, inside the trains PM1, PM2.5 and PM10 average concentrations were significantly lower compared to the Syntagma Station Platform, reaching 8 μg m-3, 27 μg m-3 and 90 μg m-3 . It was also observed that particulate levels were higher over the extent of the central part of the train route. Finally, as expected CO2 levels where found to be higher inside the trains compared to the platforms and in some cases surpassed the 1,000 ppm limit during the hottest days of the experimental campaign. Temperature and humidity remained relatively stable on the platforms whereas measurements inside the cabin fluctuated depending on the trains track locations reaching 34.8° C at the central sector of the route. KEYWORDS: Particulate pollution, Athens underground, indoor air quality, urban pollution, transportation

Design and Performance of the Sorbent-Based Atmosphere Revitalization System for Orion

NASA Technical Reports Server (NTRS)

Ritter, James A.; Reynolds, Steven P.; Ebner, Armin D.; Knox, James C.; LeVan, M. Douglas

2007-01-01

Validation and simulations of a real-time dynamic cabin model were conducted on the sorbent-based atmosphere revitalization system for Orion. The dynamic cabin model, which updates the concentration of H2O and CO2 every second during the simulation, was able to predict the steady state model values for H2O and CO2 for long periods of steady metabolic production for a 4-person crew. It also showed similar trends for the exercise periods, where there were quick changes in production rates. Once validated, the cabin model was used to determine the effects of feed flow rate, cabin volume and column volume. A higher feed flow rate reduced the cabin concentrations only slightly over the base case, a larger cabin volume was able to reduce the cabin concentrations even further, and the lower column volume led to much higher cabin concentrations. Finally, the cabin model was used to determine the effect of the amount of silica gel in the column. As the amount increased, the cabin concentration of H2O decreased, but the cabin concentration of CO2 increased.

New method for evaluating high-quality fog protective coatings

NASA Astrophysics Data System (ADS)

Czeremuszkin, Grzegorz; Latreche, Mohamed; Mendoza-Suarez, Guillermo

2011-05-01

Fogging is commonly observed when humid-warm air contacts the cold surface of a transparent substrate, i.e. eyewear lenses, making the observed image blurred and hazy. To protect from fogging, the lens inner surfaces are protected with Anti-Fog coatings, which render them hydrophilic and induce water vapor condensation as a smooth, thin and invisible film, which uniformly flows down on the lens as the condensation progresses. Coatings differ in protection level, aging kinetics, and susceptibility to contamination. Some perform acceptably in limited conditions, beyond which the condensing water film becomes unstable, nonuniform, and scatters light or shows refractory distortions, both affecting the observed image. Quantifying the performance of Anti-Fog coated lenses is difficult: they may not show classical fogging and the existing testing methods, based on fog detection, are therefore inapplicable. The presented method for evaluating and quantifying AF properties is based on characterizing light scattering on lenses exposed to controlled humidity and temperature. Changes in intensity of laser light scattered at low angles (1, 2 4 and 8 degrees), observed during condensation of water on lenses, provide information on the swelling of Anti-Fog coatings, formation of uniform water film, going from an unstable to a steady state, and on the coalescence of discontinuous films. Real time observations/measurements allow for better understanding of factors controlling fogging and fog preventing phenomena. The method is especially useful in the development of new coatings for military-, sport-, and industrial protective eyewear as well as for medical and automotive applications. It allows for differentiating between coatings showing acceptable, good, and excellent performance.

One man electrochemical air revitalization system

NASA Technical Reports Server (NTRS)

Huddleston, J. C.; Aylward, J. R.

1975-01-01

An integrated water vapor electrolysis (WVE) hydrogen depolarized CO2 concentrator (HDC) system sized for one man support over a wide range of inlet air conditions was designed, fabricated, and tested. Data obtained during 110 days of testing verified that this system can provide the necessary oxygen, CO2 removal, and partial humidity control to support one man (without exceeding a cabin partial pressure of 3.0 mmHg for CO2 and while maintaining a 20% oxygen level), when operated at a WVE current of 50 amperes and an HDC current of 18 amperes. An evaluation to determine the physical properties of tetramethylammonium bicarbonate (TMAC) and hydroxide was made. This provides the necessary electrolyte information for designing an HDC cell using TMAC.

75 FR 4539 - Energy Conservation Program for Consumer Products: Publication of the Petition for Waiver and...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-01-28

... procedure for determining the energy consumption of electric refrigerators and refrigerator-freezers. The... condensation. The existing test procedure does not take humidity or adaptive control technology into account. Therefore, Electrolux has suggested an alternate test procedure that takes adaptive control technology into...

40 CFR 86.127-12 - Test procedures; overview.

Code of Federal Regulations, 2010 CFR

2010-07-01

... applicable for determining emission results for vehicle exhaust emission systems designed to comply with the... dry air (approximately 40 percent relative humidity); (iii) Simulated solar heat intensity of 850 W/m2... conditioner system condenser cooling at all vehicle speeds (see § 86.161-00(e)). (3) Manufacturers have the...

40 CFR 86.127-12 - Test procedures; overview.

Code of Federal Regulations, 2011 CFR

2011-07-01

... applicable for determining emission results for vehicle exhaust emission systems designed to comply with the... dry air (approximately 40 percent relative humidity); (iii) Simulated solar heat intensity of 850 W/m2... conditioner system condenser cooling at all vehicle speeds (see § 86.161-00(e)). (3) Manufacturers have the...

14 CFR 25.832 - Cabin ozone concentration.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Cabin ozone concentration. 25.832 Section... Cabin ozone concentration. (a) The airplane cabin ozone concentration during flight must be shown not to... demonstrate that either— (1) The airplane cannot be operated at an altitude which would result in cabin ozone...

14 CFR 25.832 - Cabin ozone concentration.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Cabin ozone concentration. 25.832 Section... Cabin ozone concentration. (a) The airplane cabin ozone concentration during flight must be shown not to... demonstrate that either— (1) The airplane cannot be operated at an altitude which would result in cabin ozone...

14 CFR 25.832 - Cabin ozone concentration.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Cabin ozone concentration. 25.832 Section... Cabin ozone concentration. (a) The airplane cabin ozone concentration during flight must be shown not to... demonstrate that either— (1) The airplane cannot be operated at an altitude which would result in cabin ozone...

14 CFR 25.832 - Cabin ozone concentration.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Cabin ozone concentration. 25.832 Section... Cabin ozone concentration. (a) The airplane cabin ozone concentration during flight must be shown not to... demonstrate that either— (1) The airplane cannot be operated at an altitude which would result in cabin ozone...

14 CFR 25.832 - Cabin ozone concentration.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Cabin ozone concentration. 25.832 Section... Cabin ozone concentration. (a) The airplane cabin ozone concentration during flight must be shown not to... demonstrate that either— (1) The airplane cannot be operated at an altitude which would result in cabin ozone...

14 CFR 23.841 - Pressurized cabins.

Code of Federal Regulations, 2013 CFR

2013-01-01

... emergency procedure. A 17-second flight crew recognition and reaction time must be applied between cabin... pressurization system must prevent the cabin altitude from exceeding the cabin altitude-time history shown in... exceeds 25,000 feet, the maximum time the cabin altitude may exceed 25,000 feet is 2 minutes; time...

14 CFR 23.841 - Pressurized cabins.

Code of Federal Regulations, 2014 CFR

2014-01-01

... emergency procedure. A 17-second flight crew recognition and reaction time must be applied between cabin... pressurization system must prevent the cabin altitude from exceeding the cabin altitude-time history shown in... exceeds 25,000 feet, the maximum time the cabin altitude may exceed 25,000 feet is 2 minutes; time...

14 CFR 125.113 - Cabin interiors.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Cabin interiors. 125.113 Section 125.113....113 Cabin interiors. (a) Upon the first major overhaul of an airplane cabin or refurbishing of the cabin interior, all materials in each compartment used by the crew or passengers that do not meet the...

Use of a double condenser in a dehumidifier with a spray dryer for vitamin A extraction in tomato as a heat-sensitive material

NASA Astrophysics Data System (ADS)

Kosasih, E. A.; Warjito, H., Imansyah I.; Ruhyat, N.

2017-06-01

Spray dryers are commonly operated at a high temperature (>100 °C), which becomes an obstacle for heat-sensitive materials. In this study, a refrigeration system that uses evaporator as dehumidifier and that recovers the heat released from the first condenser to preheat the drying air was utilised to reduce the drying temperature. Results showed that the degradation of vitamin A (measured with the high performance liquid chromatography method) in tomato increased significantly when the drying air temperature increased from 90 °C to 120 °C, and it cannot be controlled at a temperature higher than 120 °C. At an air flow rate of 450 lpm, the drying capacity at a drying air temperature of 60 °C (with refrigeration, humidity ratio of 0.005 [kg H2O / kg dry air]) is equal to the drying capacity at a drying air temperature of 120 °C (without refrigeration, humidity ratio of 0.021 [kg H2O / kg dry air]). The drying capacity at a drying air temperature of 90 °C (with refrigeration) even becomes 1.5 times the drying capacity at a drying air temperature of 120 °C (without refrigeration). The combination of a spray dryer system with a refrigeration system (double condenser) is therefore beneficial for drying heat-sensitive materials, such as vitamin A.

Continuous Droplet Removal upon Dropwise Condensation of Humid Air on a Hydrophobic Micropatterned Surface

PubMed Central

2015-01-01

Combination of two physical phenomena, capillary pressure gradient and wettability gradient, allows a simple two-step fabrication process that yields a reliable hydrophobic self-cleaning condenser surface. The surface is fabricated with specific microscopic topography and further treatment with a chemically inert low-surface-energy material. This process does not require growth of nanofeatures (nanotubes) or hydrophilic–hydrophobic patterning of the surface. Trapezoidal geometry of the microfeatures facilitates droplet transfer from the Wenzel to the Cassie state and reduces droplet critical diameter. The geometry of the micropatterns enhances local coalescence and directional movement for droplets with diameter much smaller than the radial length of the micropatterns. The hydrophobic self-cleaning micropatterned condenser surface prevents liquid film formation and promotes continuous dropwise condensation cycle. Upon dropwise condensation, droplets follow a designed wettability gradient created with micropatterns from the most hydrophobic to the least hydrophobic end of the surface. The surface has higher condensation efficiency, due to its directional self-cleaning property, than a plain hydrophobic surface. We explain the self-actuated droplet collection mechanism on the condenser surface and demonstrate experimentally the creation of an effective wettability gradient over a 6 mm radial distance. In spite of its fabrication simplicity, the fabricated surface demonstrates self-cleaning property, enhanced condensation performance, and reliability over time. Our work enables creation of a hydrophobic condenser surface with the directional self-cleaning property that can be used for collection of biological (chemical, environmental) aerosol samples or for condensation enhancement. PMID:25073014

Continuous droplet removal upon dropwise condensation of humid air on a hydrophobic micropatterned surface.

PubMed

Zamuruyev, Konstantin O; Bardaweel, Hamzeh K; Carron, Christopher J; Kenyon, Nicholas J; Brand, Oliver; Delplanque, Jean-Pierre; Davis, Cristina E

2014-08-26

Combination of two physical phenomena, capillary pressure gradient and wettability gradient, allows a simple two-step fabrication process that yields a reliable hydrophobic self-cleaning condenser surface. The surface is fabricated with specific microscopic topography and further treatment with a chemically inert low-surface-energy material. This process does not require growth of nanofeatures (nanotubes) or hydrophilic-hydrophobic patterning of the surface. Trapezoidal geometry of the microfeatures facilitates droplet transfer from the Wenzel to the Cassie state and reduces droplet critical diameter. The geometry of the micropatterns enhances local coalescence and directional movement for droplets with diameter much smaller than the radial length of the micropatterns. The hydrophobic self-cleaning micropatterned condenser surface prevents liquid film formation and promotes continuous dropwise condensation cycle. Upon dropwise condensation, droplets follow a designed wettability gradient created with micropatterns from the most hydrophobic to the least hydrophobic end of the surface. The surface has higher condensation efficiency, due to its directional self-cleaning property, than a plain hydrophobic surface. We explain the self-actuated droplet collection mechanism on the condenser surface and demonstrate experimentally the creation of an effective wettability gradient over a 6 mm radial distance. In spite of its fabrication simplicity, the fabricated surface demonstrates self-cleaning property, enhanced condensation performance, and reliability over time. Our work enables creation of a hydrophobic condenser surface with the directional self-cleaning property that can be used for collection of biological (chemical, environmental) aerosol samples or for condensation enhancement.

Method and apparatus for bio-regenerative life support system

NASA Technical Reports Server (NTRS)

Cullingford, Hatice S. (Inventor)

1991-01-01

A life support system is disclosed for human habitation (cabin) which has a bioregenerative capability through the use of a plant habitat (greenhouse) whereby oxygen-rich air from the greenhouse is processed and used in the cabin and carbon dioxide-rich air from the cabin is used in the greenhouse. Moisture from the air of both cabin and greenhouse is processed and reused in both. Wash water from the cabin is processed and reused in the cabin as hygiene water, and urine from the cabin is processed and used in the greenhouse. Spent water from the greenhouse is processed and reused in the greenhouse. Portions of the processing cycles are separated between cabin and greenhouse in order to reduce to a minimum cross contamination of the two habitat systems. Other portions of the processing cycles are common to both cabin and greenhouse. The use of bioregenerative techniques permits a substantial reduction of the total consumables used by the life support system.

Using amphiphilic nanostructures to enable long-range ensemble coalescence and surface rejuvenation in dropwise condensation.

PubMed

Anderson, David M; Gupta, Maneesh K; Voevodin, Andrey A; Hunter, Chad N; Putnam, Shawn A; Tsukruk, Vladimir V; Fedorov, Andrei G

2012-04-24

Controlling coalescence events in a heterogeneous ensemble of condensing droplets on a surface is an outstanding fundamental challenge in surface and interfacial sciences, with a broad practical importance in applications ranging from thermal management of high-performance electronic devices to moisture management in high-humidity environments. Nature-inspired superhydrophobic surfaces have been actively explored to enhance heat and mass transfer rates by achieving favorable dynamics during dropwise condensation; however, the effectiveness of such chemically homogeneous surfaces has been limited because condensing droplets tend to form as pinned Wenzel drops rather than mobile Cassie ones. Here, we introduce an amphiphilic nanostructured surface, consisting of a hydrophilic base with hydrophobic tips, which promotes the periodic regeneration of nucleation sites for small droplets, thus rendering the surface self-rejuvenating. This unique amphiphilic nanointerface generates an arrangement of condensed Wenzel droplets that are fluidically linked by a wetted sublayer, promoting previously unobserved coalescence events where numerous droplets simultaneously merge, without direct contact. Such ensemble coalescences rapidly create fresh nucleation sites, thereby shifting the overall population toward smaller droplets and enhancing the rates of mass and heat transfer during condensation.

3D Imaging of Water-Drop Condensation on Hydrophobic and Hydrophilic Lubricant-Impregnated Surfaces

NASA Astrophysics Data System (ADS)

Kajiya, Tadashi; Schellenberger, Frank; Papadopoulos, Periklis; Vollmer, Doris; Butt, Hans-Jürgen

2016-04-01

Condensation of water from the atmosphere on a solid surface is an ubiquitous phenomenon in nature and has diverse technological applications, e.g. in heat and mass transfer. We investigated the condensation kinetics of water drops on a lubricant-impregnated surface, i.e., a micropillar array impregnated with a non-volatile ionic liquid. Growing and coalescing drops were imaged in 3D using a laser scanning confocal microscope equipped with a temperature and humidity control. Different stages of condensation can be discriminated. On a lubricant-impregnated hydrophobic micropillar array these are: (1) Nucleation on the lubricant surface. (2) Regular alignment of water drops between micropillars and formation of a three-phase contact line on a bottom of the substrate. (3) Deformation and bridging by coalescence which eventually leads to a detachment of the drops from the bottom substrate. The drop-substrate contact does not result in breakdown of the slippery behaviour. Contrary, on a lubricant-impregnated hydrophilic micropillar array, the condensed water drops replace the lubricant. Consequently, the surface loses its slippery property. Our results demonstrate that a Wenzel-like to Cassie transition, required to maintain the facile removal of condensed water drops, can be induced by well-chosen surface hydrophobicity.

3D Imaging of Water-Drop Condensation on Hydrophobic and Hydrophilic Lubricant-Impregnated Surfaces.

PubMed

Kajiya, Tadashi; Schellenberger, Frank; Papadopoulos, Periklis; Vollmer, Doris; Butt, Hans-Jürgen

2016-04-04

Condensation of water from the atmosphere on a solid surface is an ubiquitous phenomenon in nature and has diverse technological applications, e.g. in heat and mass transfer. We investigated the condensation kinetics of water drops on a lubricant-impregnated surface, i.e., a micropillar array impregnated with a non-volatile ionic liquid. Growing and coalescing drops were imaged in 3D using a laser scanning confocal microscope equipped with a temperature and humidity control. Different stages of condensation can be discriminated. On a lubricant-impregnated hydrophobic micropillar array these are: (1) Nucleation on the lubricant surface. (2) Regular alignment of water drops between micropillars and formation of a three-phase contact line on a bottom of the substrate. (3) Deformation and bridging by coalescence which eventually leads to a detachment of the drops from the bottom substrate. The drop-substrate contact does not result in breakdown of the slippery behaviour. Contrary, on a lubricant-impregnated hydrophilic micropillar array, the condensed water drops replace the lubricant. Consequently, the surface loses its slippery property. Our results demonstrate that a Wenzel-like to Cassie transition, required to maintain the facile removal of condensed water drops, can be induced by well-chosen surface hydrophobicity.

A humidity-controlled fast integrated mobility spectrometer (HFIMS) for rapid measurements of particle hygroscopic growth

NASA Astrophysics Data System (ADS)

Pinterich, Tamara; Spielman, Steven R.; Wang, Yang; Hering, Susanne V.; Wang, Jian

2017-12-01

We present a humidity-controlled fast integrated mobility spectrometer (HFIMS) for rapid particle hygroscopicity measurements. The HFIMS consists of a differential mobility analyzer (DMA), a relative humidity (RH) control unit and a water-based FIMS (WFIMS) coupled in series. The WFIMS (Pinterich et al., 2017) combines the fast integrated mobility spectrometer (Kulkarni and Wang, 2006a, b) with laminar flow water condensation methodologies (Hering and Stolzenburg, 2005; Spielman et al., 2017). Inside the WFIMS, particles of different electrical mobilities are spatially separated in an electric field, condensationally enlarged and imaged to provide 1 Hz measurements of size distribution spanning a factor of ˜ 3 in particle diameter, which is sufficient to cover the entire range of growth factor (GF) for atmospheric aerosol particles at 90 % RH. By replacing the second DMA of a traditional hygroscopicity tandem DMA (HTDMA) system with the WFIMS, the HFIMS greatly increases the speed of particle growth factor measurement. The performance of the HFIMS was evaluated using NaCl particles with well-known hygroscopic growth behavior and further through measurements of ambient aerosols. Results show that the HFIMS can reproduce, within 2 %, the literature values for hygroscopic growth of NaCl particles. NaCl deliquescence was observed between 76 and 77 % RH in agreement with the theoretical value of 76.5 % (Ming and Russell, 2001), and efflorescence relative humidity (43 %) was found to lie within the RH range of 41 to 56 % reported in the literature. Ambient data indicate that the HFIMS can measure the hygroscopic growth of five standard dry particle sizes ranging from 35 to 165 nm within less than 3 min, which makes it about 1 order of magnitude faster than traditional HTDMA systems.

A Humidity-controlled Fast Integrated Mobility Spectrometer (HFIMS) for rapid measurements of particle hygroscopic growth

DOE PAGES

Pinterich, Tamara; Spielman, Steven R.; Hering, Susanne; ...

2017-06-26

We present a Humidity-controlled Fast Integrated Mobility Spectrometer (HFIMS) for rapid particle hygroscopicity measurements. The HFIMS consists of a differential mobility analyzer (DMA), a relative humidity (RH) control unit and a water-based FIMS (WFIMS) coupled in series. The WFIMS (Pinterich et al., 2017) combines the Fast Integrated Mobility Spectrometer (Kulkarni and Wang, 2006a, b) with laminar flow water condensation methodologies (Hering and Stolzenburg, 2005; Spielman et al., 2017). Inside the WFIMS, particles of different electrical mobilities are spatially separated in an electric field, condensationally enlarged and imaged to provide 1-Hz measurements of size distribution spanning a factor of ~ 3more » in particle diameter, sufficient to cover the entire range of growth factor for atmospheric aerosol particles at 90 % RH. By replacing the second DMA of a traditional hygroscopicity tandem DMA (HTDMA) system with the WFIMS, the HFIMS greatly increases the speed of particle growth factor measurement. The performance of the HFIMS was evaluated using NaCl particles with well-known hygroscopic growth behavior, and further through measurements of ambient aerosols. Results show that HFIMS can reproduce, within 2 % the literature values for hygroscopic growth of NaCl particles. NaCl deliquescence was observed between 76 % and 77 % RH in agreement with the theoretical value of 76.5 % (Ming and Russell, 2001), and efflorescence relative humidity (43 %) was found to lie within the RH range of 41 % to 56 % reported in the literature. Ambient data indicate that HFIMS can measure the hygroscopic growth of five standard dry particle sizes ranging from 35 to 165 nm within less than three minutes, which makes it about an order of magnitude faster than traditional HTDMA systems.« less

A Humidity-controlled Fast Integrated Mobility Spectrometer (HFIMS) for rapid measurements of particle hygroscopic growth

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pinterich, Tamara; Spielman, Steven R.; Hering, Susanne

We present a Humidity-controlled Fast Integrated Mobility Spectrometer (HFIMS) for rapid particle hygroscopicity measurements. The HFIMS consists of a differential mobility analyzer (DMA), a relative humidity (RH) control unit and a water-based FIMS (WFIMS) coupled in series. The WFIMS (Pinterich et al., 2017) combines the Fast Integrated Mobility Spectrometer (Kulkarni and Wang, 2006a, b) with laminar flow water condensation methodologies (Hering and Stolzenburg, 2005; Spielman et al., 2017). Inside the WFIMS, particles of different electrical mobilities are spatially separated in an electric field, condensationally enlarged and imaged to provide 1-Hz measurements of size distribution spanning a factor of ~ 3more » in particle diameter, sufficient to cover the entire range of growth factor for atmospheric aerosol particles at 90 % RH. By replacing the second DMA of a traditional hygroscopicity tandem DMA (HTDMA) system with the WFIMS, the HFIMS greatly increases the speed of particle growth factor measurement. The performance of the HFIMS was evaluated using NaCl particles with well-known hygroscopic growth behavior, and further through measurements of ambient aerosols. Results show that HFIMS can reproduce, within 2 % the literature values for hygroscopic growth of NaCl particles. NaCl deliquescence was observed between 76 % and 77 % RH in agreement with the theoretical value of 76.5 % (Ming and Russell, 2001), and efflorescence relative humidity (43 %) was found to lie within the RH range of 41 % to 56 % reported in the literature. Ambient data indicate that HFIMS can measure the hygroscopic growth of five standard dry particle sizes ranging from 35 to 165 nm within less than three minutes, which makes it about an order of magnitude faster than traditional HTDMA systems.« less

Harvesting liquid from unsaturated vapor - nanoflows induced by capillary condensation

NASA Astrophysics Data System (ADS)

Vincent, Olivier; Marguet, Bastien; Stroock, Abraham

2016-11-01

A vapor, even subsaturated, can spontaneously form liquid in nanoscale spaces. This process, known as capillary condensation, plays a fundamental role in various contexts, such as the formation of clouds or the dynamics of hydrocarbons in the geological subsurface. However, large uncertainties remain on the thermodynamics and fluid mechanics of the phenomenon, due to experimental challenges as well as outstanding questions about the validity of macroscale physics at the nanometer scale. We studied experimentally the spatio-temporal dynamics of water condensation in a model nanoporous medium (pore radius 2 nm), taking advantage of the color change of the material upon hydration. We found that at low relative humidities (< 60 % RH), capillary condensation progressed in a diffusive fashion, while it occurred through a well-defined capillary-viscous imbibition front at > 60 % RH, driven by a balance between the pore capillary pressure and the condensation stress given by Kelvin equation. Further analyzing the imbibition dynamics as a function of saturation allowed us to extract detailed information about the physics of nano-confined fluids. Our results suggest excellent extension of macroscale fluid dynamics and thermodynamics even in pores 10 molecules in diameter.

Superhydrophobicity of biological and technical surfaces under moisture condensation: stability in relation to surface structure.

PubMed

Mockenhaupt, Bernd; Ensikat, Hans-Jürgen; Spaeth, Manuel; Barthlott, Wilhelm

2008-12-02

The stability of superhydrophobic properties of eight plants and four technical surfaces in respect to water condensation has been compared. Contact and sliding angles were measured after application of water drops of ambient temperature (20 degrees C) onto cooled surfaces. Water evaporating from the drops condensed, due to the temperature difference between the drops and the surface, on the cooled samples, forming "satellite droplets" in the vicinity of the drops. Surface cooling to 15, 10, and 5 degrees C showed a gradual decrease of superhydrophobicity. The decrease was dependent on the specific surface architecture of the sample. The least decrease was found on hierarchically structured surfaces with a combination of a coarse microstructure and submicrometer-sized structures, similar to that of the Lotus leaf. Control experiments with glycerol droplets, which show no evaporation, and thus no condensation, were carried out to verify that the effects with water were caused by condensation from the drop (secondary condensation). Furthermore, the superhydrophobic properties after condensation on cooled surfaces from a humid environment for 10 min were examined. After this period, the surfaces were covered with spherical water droplets, but most samples retained their superhydrophobicity. Again, the best stability of the water-repellent properties was found on hierarchically structured surfaces similar to that of the Lotus leaf.

Directly measured cabin pressure conditions during Boeing 747-400 commercial aircraft flights.

PubMed

Kelly, Paul T; Seccombe, Leigh M; Rogers, Peter G; Peters, Matthew J

2007-07-01

In the low pressure environment of commercial aircraft, hypoxaemia may be common and accentuated in patients with lung or heart disease. Regulations specify a cabin pressure not lower than 750 hPa but it is not known whether this standard is met. This knowledge is important in determining the hazards of commercial flight for patients and the validity of current flight simulation tests. Using a wrist-watch recording altimeter, cabin pressure was recorded at 60 s intervals on 45 flights in Boeing 747-400 aircraft with three airlines. A log was kept of aircraft altitude using the in-flight display. Change in cabin pressure during flight, relationship between aircraft altitude and cabin pressure and proportion of flight time with cabin pressure approaching the minimum specified by regulation were determined. Flight duration averaged 10 h. Average cabin pressure during flight was 846 hPa. There was a linear fall in cabin pressure as the aircraft cruising altitude increased. At 10,300 m (34,000 ft) cabin pressure was 843 hPa and changed 8 hPa for every 300 m (1000 ft) change in aircraft altitude (r(2) = 0.993; P < 0.001). Lowest cabin pressure was 792 hPa at 12 200 m (40,000 ft) but during only 2% of flight time was cabin pressure less than 800 hPa. Cabin pressure is determined only by the engineering of the aircraft and its altitude and in the present study was always higher than required by regulation. Current fitness-to-fly evaluations simulate cabin conditions that passengers will not experience on these aircraft. There may be increased risks to patients should new or older aircraft operate nearer to the present minimum standard.

Cabin fire simulator lavatory tests

NASA Technical Reports Server (NTRS)

Schutter, K. J.; Klinck, D. M.

1980-01-01

All tests were conducted in the Douglas Cabin Fire Simulator under in-flight ventilation conditions. All tests were allowed to continue for a period of one hour. Data obtained during these tests included: heat flux and temperatures of the lavatory; cabin temperature variations; gas analyses for O2, CO2, CO, HF, HC1, and HCN; respiration and electrocardiogram data on instrumented animal subjects (rats) exposed in the cabin; and color motion pictures. All tests resulted in a survivable cabin condition; however, occupants of the cabin would have been subjected to noxious fumes.

Space Station Biological Research Project Habitat: Incubator

NASA Technical Reports Server (NTRS)

Nakamura, G. J.; Kirven-Brooks, M.; Scheller, N. M.

2001-01-01

Developed as part of the suite of Space Station Biological Research Project (SSBRP) hardware to support research aboard the International Space Station (ISS), the Incubator is a temperature-controlled chamber, for conducting life science research with small animal, plant and microbial specimens. The Incubator is designed for use only on the ISS and is transported to/from the ISS, unpowered and without specimens, in the Multi-Purpose Logistics Module (MPLM) of the Shuttle. The Incubator interfaces with the three SSBRP Host Systems; the Habitat Holding Racks (HHR), the Life Sciences Glovebox (LSG) and the 2.5 m Centrifuge Rotor (CR), providing investigators with the ability to conduct research in microgravity and at variable gravity levels of up to 2-g. The temperature within the Specimen Chamber can be controlled between 4 and 45 C. Cabin air is recirculated within the Specimen Chamber and can be exchanged with the ISS cabin at a rate of approximately equal 50 cc/min. The humidity of the Specimen Chamber is monitored. The Specimen Chamber has a usable volume of approximately equal 19 liters and contains two (2) connectors at 28v dc, (60W) for science equipment; 5 dedicated thermometers for science; ports to support analog and digital signals from experiment unique sensors or other equipment; an Ethernet port; and a video port. It is currently manifested for UF-3 and will be launched integrated within the first SSBRP Habitat Holding Rack.

Enhanced water vapor separation by temperature-controlled aligned-multiwalled carbon nanotube membranes.

PubMed

Jeon, Wonjae; Yun, Jongju; Khan, Fakhre Alam; Baik, Seunghyun

2015-09-14

Here we present a new strategy of selectively rejecting water vapor while allowing fast transport of dry gases using temperature-controlled aligned-multiwalled carbon nanotubes (aligned-MWNTs). The mechanism is based on the water vapor condensation at the entry region of nanotubes followed by removing aggregated water droplets at the tip of the superhydrophobic aligned-MWNTs. The first condensation step could be dramatically enhanced by decreasing the nanotube temperature. The permeate-side relative humidity was as low as ∼17% and the helium-water vapor separation factor was as high as 4.62 when a helium-water vapor mixture with a relative humidity of 100% was supplied to the aligned-MWNTs. The flow through the interstitial space of the aligned-MWNTs allowed the permeability of single dry gases an order of magnitude higher than the Knudsen prediction regardless of membrane temperature. The water vapor separation performance of hydrophobic polytetrafluoroethylene membranes could also be significantly enhanced at low temperatures. This work combines the membrane-based separation technology with temperature control to enhance water vapor separation performance.

Enhancing dropwise condensation through bioinspired wettability patterning.

PubMed

Ghosh, Aritra; Beaini, Sara; Zhang, Bong June; Ganguly, Ranjan; Megaridis, Constantine M

2014-11-04

Dropwise condensation (DWC) heat transfer depends strongly on the maximum diameter (Dmax) of condensate droplets departing from the condenser surface. This study presents a facile technique implemented to gain control of Dmax in DWC within vapor/air atmospheres. We demonstrate how this approach can enhance the corresponding heat transfer rate by harnessing the capillary forces in the removal of the condensate from the surface. We examine various hydrophilic-superhydrophilic patterns, which, respectively, sustain and combine DWC and filmwise condensation on the substrate. The material system uses laser-patterned masking and chemical etching to achieve the desired wettability contrast and does not employ any hydrophobizing agent. By applying alternating straight parallel strips of hydrophilic (contact angle ∼78°) mirror-finish aluminum and superhydrophilic regions (etched aluminum) on the condensing surface, we show that the average maximum droplet size on the less-wettable domains is nearly 42% of the width of the corresponding strips. An overall improvement in the condensate collection rate, up to 19% (as compared to the control case of DWC on mirror-finish aluminum) was achieved by using an interdigitated superhydrophilic track pattern (on the mirror-finish hydrophilic surface) inspired by the vein network of plant leaves. The bioinspired interdigitated pattern is found to outperform the straight hydrophilic-superhydrophilic pattern design, particularly under higher humidity conditions in the presence of noncondensable gases (NCG), a condition that is more challenging for maintaining sustained DWC.

Effect of relative humidity on soot - secondary organic aerosol mixing: A case study from the Soot Aerosol Aging Study (PNNL-SAAS)

NASA Astrophysics Data System (ADS)

Sharma, N.; China, S.; Zaveri, R. A.; Shilling, J. E.; Pekour, M. S.; Liu, S.; Aiken, A. C.; Dubey, M. K.; Wilson, J. M.; Zelenyuk, A.; OBrien, R. E.; Moffet, R.; Gilles, M. K.; Gourihar, K.; Chand, D.; Sedlacek, A. J., III; Subramanian, R.; Onasch, T. B.; Laskin, A.; Mazzoleni, C.

2014-12-01

Atmospheric processing of fresh soot particles emitted by anthropogenic as well as natural sources alters their physical and chemical properties. For example, fresh and aged soot particles interact differently with incident solar radiation, resulting in different overall radiation budgets. Varying atmospheric chemical and meteorological conditions can result in complex soot mixing states. The Soot Aerosol Aging Study (SAAS) was conducted at the Pacific Northwest National Laboratory in November 2013 and January 2014 as a step towards understanding the evolution of mixing state of soot and its impact on climate-relevant properties. Aging experiments on diesel soot were carried out in a controlled laboratory chamber, and the effects of condensation and coagulation processes were systematically explored in separate sets of experiments. In addition to online measurement of aerosol properties, aerosol samples were collected for offline single particle analysis to investigate the evolution of the morphology, elemental composition and fine structure of sample particles from different experiments. Condensation experiments focused on the formation of α-pinene secondary organic aerosol on diesel soot aerosol seeds. Experiments were conducted to study the aging of soot under dry (RH < 2%) and humid conditions (RH ~ 80%). We present an analysis of the morphology of soot, its evolution, and its correlation with optical properties, as the condensation of α-pinene SOA is carried out for the two different RH conditions. The analysis was performed by using scanning electron microscopy, transmission electron microscopy, scanning transmission x-ray microscopy and atomic force microscopy for single particle characterization. In addition, particle size, mass, composition, shape, and density were characterized in-situ, as a function of organics condensed on soot seeds, using single particle mass spectrometer.

Assessment of impact of acoustic and nonacoustic parameters on performance and well-being

NASA Astrophysics Data System (ADS)

Mellert, Volker; Weber, Reinhard; Nocke, Christian

2004-05-01

It is of interest to estimate the influence of the environment in a specific work place area on the performance and well-being of people. Investigations have been carried out for the cabin environment of an airplane and for class rooms. Acoustics is only one issue of a variety of environmental factors, therefore the combined impact of temperature, humidity, air quality, lighting, vibration, etc. on human perception is the subject of psychophysical research. Methods for the objective assessment of subjective impressions have been developed for applications in acoustics for a long time, e.g., for concert hall acoustics, noise evaluation, and sound design. The methodology relies on questionnaires, measurement of acoustic parameters, ear-related signal processing and analysis, and on correlation of the physical input with subjective output. Methodology and results are presented from measurements of noise and vibration, temperature and humidity in aircraft simulators, and of reverberation, coloring, and lighting in a primary school, and of the environmental perception. [The work includes research with M. Klatte, A. Schick from the Psychology Department of Oldenburg University, and M. Meis from Hoerzentrum Oldenburg GmbH and with the European Project HEACE (for partners see www.heace.org).

58. View of Writer's Cabin (or Three Pines Cabin) and ...

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

58. View of Writer's Cabin (or Three Pines Cabin) and path looking from the southeast (similar to HALS no. LA-1-35) - Briarwood: The Caroline Dormon Nature Preserve, 216 Caroline Dormon Road, Saline, Bienville Parish, LA

Condensed-Phase Nitric Acid in a Tropical Subvisible Cirrus Cloud

NASA Technical Reports Server (NTRS)

Popp, P. J.; Marcy, T. P.; Watts, O. A.; Gao, R. S.; Fahey, D. W.; Weinstock, E. M.; Smith, J. B.; Herman, R. L.; Tropy, R. F.; Webster, C. r.;

Hydrolysis condensation reactions of titanium alkoxides in thin films: A study of the steric hindrance effect by X-ray photoelectron spectroscopy

NASA Astrophysics Data System (ADS)

Barlier, Vincent; Bounor-Legaré, Véronique; Boiteux, Gisèle; Davenas, Joël; Léonard, Didier

2008-06-01

An original approach based on X-ray photoelectron spectroscopy (XPS) is proposed to study the influence of the surrounding humidity on the hydrolysis-condensation reactions of five titanium alkoxides in thin films. More precisely, the influence of the nature of the ligands (propoxide, butoxide, isopropoxide, phenoxide, and 9H-carbazole-9-yl-ethyl-oxy) on the reaction rate was evidenced. The reaction advancement was evaluated by comparing XPS chemical compositions to theoretical compositions calculated for all the possible rates. XPS chemical environment information allowed validating the reliability of this approach through the evaluation of the condensation state. In both approaches, the influence of the steric hindrance on the reactivity of titanium alkoxides was highlighted to be similar to what has been previously observed in solution. Theses results corroborate the validity of our XPS approach to determine titanium alkoxide hydrolysis-condensation reactions in the specific application of thin films.

The sol-gel template synthesis of porous TiO2 for a high performance humidity sensor

NASA Astrophysics Data System (ADS)

Wang, Zhuyi; Shi, Liyi; Wu, Fengqing; Yuan, Shuai; Zhao, Yin; Zhang, Meihong

2011-07-01

This research develops a simple template assisted sol-gel process for preparing porous TiO2 for a high performance humidity sensor. Tetraethyl orthosilicate (TEOS) as a template was directly introduced into TiO2 sol formed by the hydrolysis and condensation of titanium alkoxide; the following calcination led to the formation of TiO2-SiO2 composite, and the selective removal of SiO2 by dilute HF solution led to the formation of porous structure in TiO2. The resulting porous TiO2-based sensor exhibits high sensitivity and linear response in the wide relative humidity (RH) range of 11%-95%, with an impedance variation of four orders of magnitude to humidity change. Moreover, it exhibits a rapid and highly reversible response characterized by a very small hysteresis of < 1% RH and a short response-recovery time (5 s for adsorption and 8 s for desorption), and a 30-day stability test also confirms its long-term stability. Compared with pure TiO2 prepared by the conventional sol-gel method, our product shows remarkably improved performance and good prospect for a high performance humidity sensor. The complex impedance spectra were used to elucidate its humidity sensing mechanism in detail.

STS-47 MS Davis and Pilot Brown repair ISAIAH humidity problem aboard OV-105

NASA Image and Video Library

1992-09-20

STS047-35-022 (12 - 20 Sept 1992) --- Astronauts Curtis L. Brown, Jr., pilot, and N. Jan Davis, mission specialist, team up to cure a high humidity problem in the hornet experiment in the Spacelab-J Science Module of the Earth-orbiting Space Shuttle Endeavour. Via a jury-rigged hose hook-up, the two were able to blow air from a spacesuit fan into the experiment, thus eliminating condensation that obscured the viewing of the Israeli hornet experiment. The experiment examined the effects of microgravity on the orientation, reproductive capability and social activity of 180 female Oriental Hornets.

Experimental investigation on AC unit integrated with sensible heat storage (SHS)

NASA Astrophysics Data System (ADS)

Aziz, N. A.; Amin, N. A. M.; Majid, M. S. A.; Hussin, A.; Zhubir, S.

2017-10-01

The growth in population and economy has increases the energy demand and raises the concerns over the sustainable energy source. Towards the sustainable development, energy efficiency in buildings has become a prime objective. In this paper, the integration of thermal energy storage was studied. This paper presents an experimental investigation on the performance of an air conditioning unit integrated with sensible heat storage (SHS) system. The results were compared to the conventional AC systems in the terms of average electricity usage, indoor temperature and the relative humidity inside the experimented room (cabin container). Results show that the integration of water tank as an SHS reduces the electricity usage by 5%, while the integration of well-insulated water tank saves up to 8% of the electricity consumption.

Microgravity Fluid Separation Physics: Experimental and Analytical Results

NASA Technical Reports Server (NTRS)

Shoemaker, J. Michael; Schrage, Dean S.

1997-01-01

Effective, low power, two-phase separation systems are vital for the cost-effective study and utilization of two-phase flow systems and flow physics of two-phase flows. The study of microgravity flows have the potential to reveal significant insight into the controlling mechanisms for the behavior of flows in both normal and reduced gravity environments. The microgravity environment results in a reduction in gravity induced buoyancy forces acting on the discrete phases. Thus, surface tension, viscous, and inertial forces exert an increased influence on the behavior of the flow as demonstrated by the axisymmetric flow patterns. Several space technology and operations groups have studied the flow behavior in reduced gravity since gas-liquid flows are encountered in several systems such as cabin humidity control, wastewater treatment, thermal management, and Rankine power systems.

International Space Station Environmental Control and Life Support Emergency Response Verification for Node 1

NASA Technical Reports Server (NTRS)

Williams, David E.

2008-01-01

The International Space Station (ISS) Node 1 Environmental Control and Life Support (ECLS) System is comprised of five subsystems: Atmosphere Control and Supply (ACS), Atmosphere Revitalization (AR), Fire Detection and Suppression (FDS), Temperature and Humidity Control (THC), and Water Recovery and Management (WRM). This paper provides a summary of the Node 1 Emergency Response capability, which includes nominal and off-nominal FDS operation, off nominal ACS operation, and off-nominal THC operation. These subsystems provide the capability to help aid the crew members during an emergency cabin depressurization, a toxic spill, or a fire. The paper will also provide a discussion of the detailed Node 1 ECLS Element Verification methodologies for operation of the Node 1 Emergency Response hardware operations utilized during the Qualification phase.

Water harvest via dewing.

PubMed

Lee, Anna; Moon, Myoung-Woon; Lim, Hyuneui; Kim, Wan-Doo; Kim, Ho-Young

2012-07-10

Harvesting water from humid air via dewing can provide a viable solution to a water shortage problem where liquid-phase water is not available. Here we experimentally quantify the effects of wettability and geometry of the condensation substrate on the water harvest efficiency. Uniformly hydrophilic surfaces are found to exhibit higher rates of water condensation and collection than surfaces with lower wettability. This is in contrast to a fog basking method where the most efficient surface consists of hydrophilic islands surrounded by hydrophobic background. A thin drainage path in the lower portion of the condensation substrate is revealed to greatly enhance the water collection efficiency. The optimal surface conditions found in this work can be used to design a practical device that harvests water as its biological counterpart, a green tree frog, Litoria caerulea , does during the dry season in tropical northern Australia.

Altitude exposures during commercial flight: a reappraisal.

PubMed

Hampson, Neil B; Kregenow, David A; Mahoney, Anne M; Kirtland, Steven H; Horan, Kathleen L; Holm, James R; Gerbino, Anthony J

2013-01-01

Hypobaric hypoxia during commercial air travel has the potential to cause or worsen hypoxemia in individuals with pre-existing cardiopulmonary compromise. Knowledge of cabin altitude pressures aboard contemporary flights is essential to counseling patients accurately about flying safety. The objective of the study was to measure peak cabin altitudes during U.S. domestic commercial flights on a variety of aircraft. A handheld mountaineering altimeter was carried by the investigators in the plane cabin during commercial air travel and peak cabin altitude measured. The values were then compared between aircraft models, aircraft classes, and distances flown. The average peak cabin altitude on 207 flights aboard 17 different aircraft was 6341 +/- 1813 ft (1933 m +/- 553 m), significantly higher than when measured in a similar fashion in 1988. Peak cabin altitude was significantly higher for flights longer than 750 mi (7085 +/- 801 ft) compared to shorter flights (5160 +/- 2290 ft/1573 +/- 698 m). Cabin altitude increased linearly with flight distance for flights up to 750 mi in length, but was independent of flight distance for flights exceeding 750 mi. Peak cabin altitude was less than 5000 ft (1524 m) in 70% of flights shorter than 500 mi. Peak cabin altitudes greater than 8000 ft (2438 m) were measured on approximately 10% of the total flights. Peak cabin altitude on commercial aircraft flights has risen over time. Cabin altitude is lower with flights of shorter distance. Physicians should take these factors into account when determining an individual's need for supplemental oxygen during commercial air travel.

Characteristics of cabin air quality in school buses in Central Texas

NASA Astrophysics Data System (ADS)

Rim, Donghyun; Siegel, Jeffrey; Spinhirne, Jarett; Webb, Alba; McDonald-Buller, Elena

This study assessed in-cabin concentrations of diesel-associated air pollutants in six school buses with diesel engines during a typical route in suburban Austin, Texas. Air exchange rates measured by SF 6 decay were 2.60-4.55 h -1. In-cabin concentrations of all pollutants measured exhibited substantial variability across the range of tests even between buses of similar age, mileage, and engine type. In-cabin NO x concentrations ranged from 44.7 to 148 ppb and were 1.3-10 times higher than roadway NO x concentrations. Mean in-cabin PM 2.5 concentrations were 7-20 μg m -3 and were generally lower than roadway levels. In-cabin concentrations exhibited higher variability during cruising mode than frequent stops. Mean in-cabin ultrafine PM number concentrations were 6100-32,000 particles cm -3 and were generally lower than roadway levels. Comparison of median concentrations indicated that in-cabin ultrafine PM number concentrations were higher than or approximately the same as the roadway concentrations, which implied that, by excluding the bias caused by local traffic, ultrafine PM levels were higher in the bus cabin than outside of the bus. Cabin pollutant concentrations on three buses were measured prior to and following the phased installation of a Donaldson Spiracle Crankcase Filtration System and a Diesel Oxidation Catalyst. Following installation of the Spiracle, the Diesel Oxidation Catalyst provided negligible or small additional reductions of in-cabin pollutant levels. In-cabin concentration decreases with the Spiracle alone ranged from 24 to 37% for NO x and 26 to 62% and 6.6 to 43% for PM 2.5 and ultrafine PM, respectively. Comparison of the ranges of PM 2.5 and ultrafine PM variations between repetitive tests suggested that retrofit installation could not always be conclusively linked to the decrease of pollutant levels in the bus cabin.

Design Concept for a Minimal Volume Spacecraft Cabin to Serve as a Mars Ascent Vehicle Cabin and Other Alternative Pressurized Vehicle Cabins

NASA Technical Reports Server (NTRS)

Howard, Robert L., Jr.

2016-01-01

The Evolvable Mars Campaign is developing concepts for human missions to the surface of Mars. These missions are round-trip expeditions, thereby requiring crew launch via a Mars Ascent Vehicle (MAV). A study to identify the smallest possible pressurized cabin for this mission has developed a conceptual vehicle referred to as the minimal MAV cabin. The origin of this concept will be discussed as well as its initial concept definition. This will lead to a description of possible configurations to integrate the minimal MAV cabin with ascent vehicle engines and propellant tanks. Limitations of this concept will be discussed, in particular those that argue against the use of the minimal MAV cabin to perform the MAV mission. However, several potential alternative uses for the cabin are identified. Finally, recommended forward work will be discussed, including current work in progress to develop a full scale mockup and conduct usability evaluations.

Ozone contamination in aircraft cabins - Results from GASP data and analyses

NASA Technical Reports Server (NTRS)

Holdeman, J. D.; Nastrom, G. D.

1981-01-01

The paper reviews results from the NASA Global Atmospheric Sampling Program (GASP) pertaining to the problem of ozone contamination in commercial aircraft cabins. Specifically, analyses of GASP data have (1) confirmed the high ozone levels in aircraft cabins and documented the ratio of ozone inside and outside the cabins of two B747 airliners, including the effects of air conditioning modifications on that ratio; (2) defined ambient ozone climatology at commercial aircraft cruise altitudes, including tabulation of encounter frequency data; and (3) outlined procedures for estimating the frequency of flights encountering high cabin ozone levels using climatological ambient ozone data and verified these procedures against cabin measurements.

Ozone contamination in aircraft cabins: Results from GASP data and analyses

NASA Technical Reports Server (NTRS)

Holdeman, J. D.; Nastrom, G. D.

1981-01-01

The global atmospheric sampling program pertaining to the problem of ozone contamination in commercial airplane cabins is described. Specifically, analyses of GASP data have: confirmed the occurrence of high ozone levels in aircraft cabins and documented the ratio of ozone inside and outside the cabins of two B747 airliners, including the effects of air conditioning modifications on that ratio; defined ambient ozone climatology at commercial airplane cruise altitudes, including tabulation of encounter frequency data which were not available before GASP; and outlined procedures for estimating the frequency of flights encountering high cabin ozone levels using climatological ambient ozone data, and verified these procedures against cabin measurements.

Aircraft cabin ozone measurements on B747-100 and B747-SP aircraft: Correlations with atmospheric ozone and ozone encounter statistics

NASA Technical Reports Server (NTRS)

Perkins, P. J.; Holdeman, J. D.; Gauntner, D. J.

1978-01-01

Simultaneous measurements of atmospheric (outside) ozone concentration and ozone levels in the cabin of the B747-100 and B747-SP airliners were made by NASA to evaluate the aircraft cabin ozone contamination problem. Instrumentation on these aircraft measured ozone from an outside probe and at one point in the cabin. Average ozone in the cabin of the B747-100 was 39 percent of the outside. Ozone in the cabin of the B747-SP measured 82 percent of the outside, before corrective measures. Procedures to reduce the ozone in this aircraft included changes in the cabin air circulation system, use of the high-temperature 15th stage compressor bleed, and charcoal filters in the inlet cabin air ducting, which as separate actions reduced the ozone to 58, 19 and 5 percent, respectively. The potential for the NASA instrumented B747 aircraft to encounter high levels of cabin ozone was derived from atmospheric oxone measurements on these aircraft. Encounter frequencies for two B747-100's were comparable even though the route structures were different. The B747-SP encountered high ozone than did the B747-100's.

Furry pet allergens, fungal DNA and microbial volatile organic compounds (MVOCs) in the commercial aircraft cabin environment.

PubMed

Fu, Xi; Lindgren, Torsten; Guo, Moran; Cai, Gui-Hong; Lundgren, Håkan; Norbäck, Dan

2013-06-01

There has been concern about the cabin environment in commercial aircraft. We measured cat, dog and horse allergens and fungal DNA in cabin dust and microbial volatile organic compounds (MVOCs) in cabin air. Samples were collected from two European airline companies, one with cabins having textile seats (TSC) and the other with cabins having leather seats (LSC), 9 airplanes from each company. Dust was vacuumed from seats and floors in the flight deck and different parts of the cabin. Cat (Fel d1), dog (Can f1) and horse allergens (Equ cx) were analyzed by ELISA. Five sequences of fungal DNA were analyzed by quantitative PCR. MVOCs were sampled on charcoal tubes in 42 TSC flights, and 17 compounds were analyzed by gas chromatography mass spectrometry (GC-MS) with selective ion monitoring (SIM). MVOC levels were compared with levels in homes from Nordic countries. The weight of dust was 1.8 times larger in TSC cabins as compared to LSC cabins (p < 0.001). In cabins with textile seats, the geometric mean (GM) concentrations of Fel d1, Can f1 and Equ cx were 5359 ng g(-1), 6067 ng g(-1), and 13 703 ng g(-1) (GM) respectively. Levels of Fel d1, Can f1 and Equ cx were 50 times, 27 times and 75 times higher respectively, in TSC cabins as compared to LSC cabins (p < 0.001). GM levels of Aspergillus/Penicillium DNA, Aspergillus versicolor DNA, Stachybotrys chartarum DNA and Streptomyces DNA were all higher in TSC as compared to LSC (p < 0.05). The sum of MVOCs in cabin air (excluding butanols) was 3192 ng m(-3) (GM), 3.7 times higher than in homes (p < 0.001) and 2-methyl-1-butanol and 3-methyl-1-butanol concentrations were 15-17 times higher as compared to homes (p < 0.001). Concentrations of isobutanol, 1-butanol, dimethyldisulfide, 2-hexanone, 2-heptanone, 3-octanone, isobutyl acetate and ethyl-2-methylbutyrate were lower in cabin air as compared to homes (p < 0.05). In conclusion, textile seats are much more contaminated by pet allergens and fungal DNA than leather seats. The use of seats with smooth surfaces should be encouraged. The MVOC levels differed between cabin air and homes.

14 CFR 121.578 - Cabin ozone concentration.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 3 2014-01-01 2014-01-01 false Cabin ozone concentration. 121.578 Section... REQUIREMENTS: DOMESTIC, FLAG, AND SUPPLEMENTAL OPERATIONS Flight Operations § 121.578 Cabin ozone concentration... successfully demonstrated to the Administrator that the concentration of ozone inside the cabin will not exceed...

14 CFR 121.578 - Cabin ozone concentration.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 false Cabin ozone concentration. 121.578 Section... REQUIREMENTS: DOMESTIC, FLAG, AND SUPPLEMENTAL OPERATIONS Flight Operations § 121.578 Cabin ozone concentration... successfully demonstrated to the Administrator that the concentration of ozone inside the cabin will not exceed...

14 CFR 121.578 - Cabin ozone concentration.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Cabin ozone concentration. 121.578 Section... REQUIREMENTS: DOMESTIC, FLAG, AND SUPPLEMENTAL OPERATIONS Flight Operations § 121.578 Cabin ozone concentration... successfully demonstrated to the Administrator that the concentration of ozone inside the cabin will not exceed...

14 CFR 121.578 - Cabin ozone concentration.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 false Cabin ozone concentration. 121.578 Section... REQUIREMENTS: DOMESTIC, FLAG, AND SUPPLEMENTAL OPERATIONS Flight Operations § 121.578 Cabin ozone concentration... successfully demonstrated to the Administrator that the concentration of ozone inside the cabin will not exceed...

14 CFR 121.578 - Cabin ozone concentration.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Cabin ozone concentration. 121.578 Section... REQUIREMENTS: DOMESTIC, FLAG, AND SUPPLEMENTAL OPERATIONS Flight Operations § 121.578 Cabin ozone concentration... successfully demonstrated to the Administrator that the concentration of ozone inside the cabin will not exceed...

Environmental Degradation of Fiber-Reinforced Polymer Fasteners in Wood

Treesearch

Samuel L. Zelinka; Douglas R. Rammer

2013-01-01

This paper examines the durability of fiber-reinforced polymer (FRP) nails in treated wood. The FRP nails were exposed to four conditions: (1) accelerated weathering, consisting of exposure to ultraviolet light and condensation; (2) 100% relative humidity (RH); (3) being driven into untreated wood and exposed to 100% RH; and (4) being driven into wood treated with...

Chemical treatments for improving compressive strength of linerboard at high moisture conditions

Treesearch

D. J. Fahey

1964-01-01

Various chemical treatments have been investigated at the Forest Products Laboratory for improving the compressive strength of linerboard exposed at high humidities and after water-soaking. Phenolic resins have been among the more promising chemicals studied, but they vary in performance. The low-condensed water-soluble phenolic resins have given some of the highest...

Ion generation and CPC detection efficiency studies in sub 3-nm size range

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kangasluoma, J.; Junninen, H.; Sipilae, M.

2013-05-24

We studied the chemical composition of commonly used condensation particle counter calibration ions with a mass spectrometer and found that in our calibration setup the negatively charged ammonium sulphate, sodium chloride and tungsten oxide are the least contaminated whereas silver on both positive and negative and the three mentioned earlier in positive mode are contaminated with organics. We report cut-off diameters for Airmodus Particle Size Magnifier (PSM) 1.1, 1.3, 1.4, 1.6 and 1.6-1.8 nm for negative sodium chloride, ammonium sulphate, tungsten oxide, silver and positive organics, respectively. To study the effect of sample relative humidity on detection efficiency of themore » PSM we used different humidities in the differential mobility analyzer sheath flow and found that with increasing relative humidity also the detection efficiency of the PSM increases.« less

Desiccant-assisted air conditioner improves IAQ and comfort

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meckler, M.

1994-10-01

This article describes a system which offers the advantage of downsizing the evaporator coil and condensing unit capacities for comparable design loads, which in turn provides numerous benefits. Airborne microorganisms, which are responsible for many acute diseases, infections, and allergies, are well protected indoors by the moisture surrounding them. While the human body is generally the host for various bacteria and viruses, fungi can grow in moist places. It has been concluded that an optimum relative humidity (RH) range of 40 to 60 percent is necessary to minimize or eliminate the bacterial, viral, and fungal growth. In addition, humidity alsomore » has an effect on air cleanliness--it reduces the presence of dust particles--and on the deterioration of the building structure and its contents. Therefore, controlling humidity is a very important factor to human comfort in minimizing adverse health effects and maximizing the structural longevity of the building.« less

75 FR 38945 - Airworthiness Directives; The Boeing Company Model 777-200 and -300 Series Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-07

..., 2006. The service bulletin describes procedures for installing new operational software in the cabin... loading the new cabin services system central storage device software and CSCP OPS into the MMC. FAA's... cabin services system central storage device software and cabin system control panel operational...

A new device for 100 per cent humidification of inspired air

PubMed Central

Larsson, Anders; Gustafsson, Ann; Svanborg, Lennart

2000-01-01

Introduction: Devices for active humidification of the inspired air in mechanically ventilated patients cause water condensation in the ventilator tubing, which may become contaminated or interfere with the function of the ventilator. The present study describes and tests the performance of a new humidifier, which is designed to eliminate water condensation. Objectives: To test the performance of the new humidifier at different ventilator settings in a lung model, and to compare this new humidifier with a conventional active humidifier in ventilator-treated critically ill patients. Materials and methods: The humidifier (Humid-Heat; Louis Gibeck AB, Upplands Väsby, Sweden) consists of a supply unit with a microprocessor and a water pump, and a humidification device, which is placed between the Y-piece and the endotracheal tube. The humidification device is based on a hygroscopic heat-moisture exchanger (HME), which absorbs the expired heat and moisture and releases it into the inspired gas. External heat and water are then added to the patient side of the HME, so the inspired gas should reach 100% humidity at 37°C (44 mg H2O/l air). The external water is delivered to the humidification device via a pump onto a wick and then evaporated into the inspired air by an electrical heater. The microprocessor controls the water pump and the heater by an algorithm using the minute ventilation (which is fed into the microprocessor) and the airway temperature measured by a sensor mounted in the flex-tube on the patient side of the humidification device. The performance characteristics were tested in a lung model ventilated with a constant flow (inspiratory:expiratory ratio 1:2, rate 12–20 breaths/min and a minute ventilation of 3–25 l/min) or with a decelerating flow (inspiratory:expiratory ratio 1:2, rate 12–15 breaths/min and a minute ventilation of 4.7–16.4 l/min). The device was also tested prospectively and in a randomized order compared with a conventional active humidifier (Fisher & Paykel MR730, Auckland, New Zealand) in eight mechanically ventilated, endotracheally intubated patients in the intensive care unit. The test period with each device was 24 h. The amount of fluid consumed and the amount of water in the water traps were measured. The number of times that the water traps were emptied, changes of machine filters, the suctions and quality of secretions, nebulizations, and the amount of saline instillations and endotracheal tube obstruction were recorded. In order to evaluate increased expiratory resistance due to the device, the airway pressure was measured at the end of a prolonged end-expiratory pause at 1 h of use and at the end of the test, and was compared with the corresponding pressure before the experiment. The body temperature of the patient was measured before and after the test of each device. Results: Both with constant flow and decelerating flow, the Humid-Heat gave an absolute humidity of 41–44 mgH2O/l at 37°C, with the lower level at the highest ventilation. In the patients, both Humid-Heat and the conventional active humidifier (MR730) maintained temperatures, indicating that they provided the intended heat and moisture to the inspired air. With both devices, the body temperature was maintained during the test period. There was no difference in the amount of secretions, the quality of the secretions and the frequency of suctions, saline instillations or nebulizations between the test periods with the two devices. There was no endotracheal tube obstruction, and after 1 h of use and at the end of the test no increased airway resistance was found with either device. When the MR730 was used, however, the water traps needed to be emptied six to 14 (mean eight) times (total amount of fluid in the traps was 100–300 ml) and the machine filters were changed two to six (mean four) times due to an excessive amount of condensed water with flow obstruction. No condensation of water was found in the tubing with the Humid-Heat. The water consumption was 23–65 ml/h (mean 30 ml/h) with the MR730 and 4–8 ml/h (mean 6 ml/h) with the Humid-Heat (P < 0.0008). The same relations were found when the water consumption was corrected for differences in minute ventilation. Discussion: The new humidifier, the Humid-Heat, gave an absolute humidity of 41–44 mg/l at 37°C in the bench tests. The tests in ventilated patients showed that the device was well tolerated and that condensation in the tubing was eliminated. There was no need to empty water traps. The test period was too short to evaluate whether the new device had any other advantages or disadvantages compared with conventional humidifiers. PMID:11056746

3D Imaging of Water-Drop Condensation on Hydrophobic and Hydrophilic Lubricant-Impregnated Surfaces

PubMed Central

Kajiya, Tadashi; Schellenberger, Frank; Papadopoulos, Periklis; Vollmer, Doris; Butt, Hans-Jürgen

2016-01-01

Condensation of water from the atmosphere on a solid surface is an ubiquitous phenomenon in nature and has diverse technological applications, e.g. in heat and mass transfer. We investigated the condensation kinetics of water drops on a lubricant-impregnated surface, i.e., a micropillar array impregnated with a non-volatile ionic liquid. Growing and coalescing drops were imaged in 3D using a laser scanning confocal microscope equipped with a temperature and humidity control. Different stages of condensation can be discriminated. On a lubricant-impregnated hydrophobic micropillar array these are: (1) Nucleation on the lubricant surface. (2) Regular alignment of water drops between micropillars and formation of a three-phase contact line on a bottom of the substrate. (3) Deformation and bridging by coalescence which eventually leads to a detachment of the drops from the bottom substrate. The drop-substrate contact does not result in breakdown of the slippery behaviour. Contrary, on a lubricant-impregnated hydrophilic micropillar array, the condensed water drops replace the lubricant. Consequently, the surface loses its slippery property. Our results demonstrate that a Wenzel-like to Cassie transition, required to maintain the facile removal of condensed water drops, can be induced by well-chosen surface hydrophobicity. PMID:27040483

89. Puckett Cabin. The cabin constructed by John Puckett around ...

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

89. Puckett Cabin. The cabin constructed by John Puckett around 1865 is a good example of the one-room log cabin once common to the mountains. This was the home of Mrs. Oleana Puckett who died in 1939 at the age of 102. She worked as a midwife in the surrounding area, assisting in the delivery of more than 1,000 children. View looking east. - Blue Ridge Parkway, Between Shenandoah National Park & Great Smoky Mountains, Asheville, Buncombe County, NC

Appendices to the model description document for a computer program for the emulation/simulation of a space station environmental control and life support system

NASA Technical Reports Server (NTRS)

Yanosy, James L.

1988-01-01

A Model Description Document for the Emulation Simulation Computer Model was already published. The model consisted of a detailed model (emulation) of a SAWD CO2 removal subsystem which operated with much less detailed (simulation) models of a cabin, crew, and condensing and sensible heat exchangers. The purpose was to explore the utility of such an emulation simulation combination in the design, development, and test of a piece of ARS hardware, SAWD. Extensions to this original effort are presented. The first extension is an update of the model to reflect changes in the SAWD control logic which resulted from test. Also, slight changes were also made to the SAWD model to permit restarting and to improve the iteration technique. The second extension is the development of simulation models for more pieces of air and water processing equipment. Models are presented for: EDC, Molecular Sieve, Bosch, Sabatier, a new condensing heat exchanger, SPE, SFWES, Catalytic Oxidizer, and multifiltration. The third extension is to create two system simulations using these models. The first system presented consists of one air and one water processing system. The second consists of a potential air revitalization system.

Appendices to the user's manual for a computer program for the emulation/simulation of a space station environmental control and life support system

NASA Technical Reports Server (NTRS)

Yanosy, James L.

1988-01-01

A user's Manual for the Emulation Simulation Computer Model was published previously. The model consisted of a detailed model (emulation) of a SAWD CO2 removal subsystem which operated with much less detailed (simulation) models of a cabin, crew, and condensing and sensible heat exchangers. The purpose was to explore the utility of such an emulation/simulation combination in the design, development, and test of a piece of ARS hardware - SAWD. Extensions to this original effort are presented. The first extension is an update of the model to reflect changes in the SAWD control logic which resulted from the test. In addition, slight changes were also made to the SAWD model to permit restarting and to improve the iteration technique. The second extension is the development of simulation models for more pieces of air and water processing equipment. Models are presented for: EDC, Molecular Sieve, Bosch, Sabatier, a new condensing heat exchanger, SPE, SFWES, Catalytic Oxidizer, and multifiltration. The third extension is to create two system simulations using these models. The first system presented consists of one air and one water processing system, the second a potential Space Station air revitalization system.

Investigation of acoustic properties of a rigid foam with application to noise reduction in light aircraft

NASA Technical Reports Server (NTRS)

Holmer, C. I.

1972-01-01

A analytic model of sound transmission into an aircraft cabin was developed as well as test procedures which appropriately rank order properties which affect sound transmission. The proposed model agrees well with available data, and reveals that the pertinent properties of an aircraft cabin for sound transmission include: stiffness of cabin walls at low frequencies (as this reflects on impedance of the walls) and cabin wall transmission loss and interior absorption at mid and high frequencies. Below 315 Hz the foam contributes substantially to wall stiffness and sound transmission loss of typical light aircraft cabin construction, and could potentially reduce cabin noise levels by 3-5 db in this frequency range at a cost of about 0:2 lb/sq. ft. of treated cabin area. The foam was found not to have significant sound absorbing properties.

Enhancement of Condensation Heat Transfer by Counter-Corrent Wavy Flow in a Vertical Tube

NASA Astrophysics Data System (ADS)

Teranishi, Tsunenobu; Ozawa, Takanori; Takimoto, Akira

As a basic research for the development of a high-performance and environment-friendly thermal energy recovery system, detailed experiments have been conducted to investigate the mechanism of the enhancement of condensation heat transfer by the counter-current moist air flow in a vertical tube. From the results of visual observation of the phenomena by using a high-speed video recorder and the measurement of condensate rate respectively from an upper and a bottom end of a cooled tube, in which various humidity vapor of air and water flowed upward or downward, the dynamic behavior of liquid film condensed on cooled surface and moist air flow was classified into four distinctive patterns in quality and quantity. Further, the effect of the scale and the operating condition such as the diameter and the length of tube, the vapor concentration and the moist air temperature, on the condensation rate of counter-current wavy flow was clarified in relation to the pattern and condition of occurrence of the wavy flow of liquid film and flooding due to the shear forces between the interface of liquid and moist air flow.

Wireless Network Simulation in Aircraft Cabins

NASA Technical Reports Server (NTRS)

Beggs, John H.; Youssef, Mennatoallah; Vahala, Linda

2004-01-01

An electromagnetic propagation prediction tool was used to predict electromagnetic field strength inside airplane cabins. A commercial software package, Wireless Insite, was used to predict power levels inside aircraft cabins and the data was compared with previously collected experimental data. It was concluded that the software could qualitatively predict electromagnetic propagation inside the aircraft cabin environment.

14 CFR 23.841 - Pressurized cabins.

Code of Federal Regulations, 2012 CFR

2012-01-01

... descent is made by an approved emergency procedure. A 17-second flight crew recognition and reaction time... altitude-time history shown in Figure 1 of this section. (ii) Maximum cabin altitude is limited to 30,000 feet. If cabin altitude exceeds 25,000 feet, the maximum time the cabin altitude may exceed 25,000 feet...

The potential for pulmonary heat injury resulting from the activation of a cabin water spray system to fight aircraft cabin fires.

DOT National Transportation Integrated Search

1995-05-01

A cabin water spray system (CWSS) has been suggested as a means of attenuating the severity of smoke and fire commonly associated with aircraft accidents. All aspects of passenger and cabin safety must be considered when evaluating a new safety syste...

Field measurement of moisture-buffering model inputs for residential buildings

DOE PAGES

Woods, Jason; Winkler, Jon

2016-02-05

Moisture adsorption and desorption in building materials impact indoor humidity. This effect should be included in building-energy simulations, particularly when humidity is being investigated or controlled. Several models can calculate this moisture-buffering effect, but accurate ones require model inputs that are not always known to the user of the building-energy simulation. This research developed an empirical method to extract whole-house model inputs for the effective moisture penetration depth (EMPD) model. The experimental approach was to subject the materials in the house to a square-wave relative-humidity profile, measure all of the moisture-transfer terms (e.g., infiltration, air-conditioner condensate), and calculate the onlymore » unmeasured term—the moisture sorption into the materials. We validated this method with laboratory measurements, which we used to measure the EMPD model inputs of two houses. After deriving these inputs, we measured the humidity of the same houses during tests with realistic latent and sensible loads and demonstrated the accuracy of this approach. Furthermore, these results show that the EMPD model, when given reasonable inputs, is an accurate moisture-buffering model.« less

A newly developed tool for intra-tracheal temperature and humidity assessment in laryngectomized individuals: the Airway Climate Explorer (ACE)

PubMed Central

Zuur, J. K.; Muller, S. H.; de Jongh, F. H. C.; van der Horst, M. J.; Shehata, M.; van Leeuwen, J.; Sinaasappel, M.

2007-01-01

The aim of this study is to develop a postlaryngectomy airway climate explorer (ACE) for assessment of intratracheal temperature and humidity and of influence of heat and moisture exchangers (HMEs). Engineering goals were within-device condensation prevention and fast response time characteristics. The ACE consists of a small diameter, heated air-sampling catheter connected to a heated sensor house, containing a humidity sensor. Air is sucked through the catheter by a controlled-flow pump. Validation was performed in a climate chamber using a calibrated reference sensor and in a two-flow system. Additionally, the analyser was tested in vivo. Over the clinically relevant range of humidity values (5–42 mg H2O/l air) the sensor output highly correlates with the reference sensor readings (R2 > 0.99). The 1–1/e response times are all <0.5 s. A first in vivo pilot measurement was successful. The newly developed, verified, fast-responding ACE is suitable for postlaryngectomy airway climate assessment. PMID:17629761

DOE Office of Scientific and Technical Information (OSTI.GOV)

Woods, Jason; Winkler, Jon

Moisture adsorption and desorption in building materials impact indoor humidity. This effect should be included in building-energy simulations, particularly when humidity is being investigated or controlled. Several models can calculate this moisture-buffering effect, but accurate ones require model inputs that are not always known to the user of the building-energy simulation. This research developed an empirical method to extract whole-house model inputs for the effective moisture penetration depth (EMPD) model. The experimental approach was to subject the materials in the house to a square-wave relative-humidity profile, measure all of the moisture-transfer terms (e.g., infiltration, air-conditioner condensate), and calculate the onlymore » unmeasured term—the moisture sorption into the materials. We validated this method with laboratory measurements, which we used to measure the EMPD model inputs of two houses. After deriving these inputs, we measured the humidity of the same houses during tests with realistic latent and sensible loads and demonstrated the accuracy of this approach. Furthermore, these results show that the EMPD model, when given reasonable inputs, is an accurate moisture-buffering model.« less

Thermodynamic and liquid profiling during the 2010 Winter Olympics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ware, R.; Cimini, D.; Campos, E.

2013-10-01

Tropospheric observations by a microwave profiling radiometer and six-hour radiosondes were obtained during the Alpine Venue of the 2010 Winter Olympic Games at Whistler, British Columbia, by Environment Canada. The radiometer provided continuous temperature, humidity and liquid (water) profiles during all weather conditions including rain, sleet and snow. Gridded analysis was provided by the U.S. National Oceanic and Atmospheric Administration. We compare more than two weeks of radiometer neural network and radiosonde temperature and humidity soundings including clear and precipitating conditions. Corresponding radiometer liquid and radiosonde wind soundings are shown. Close correlation is evident between radiometer and radiosonde temperature andmore » humidity profiles up to 10 km height and among southwest winds, liquid water and upper level thermodynamics, consistent with up-valley advection and condensation of moist maritime air. We compare brightness temperatures observed by the radiometer and forward-modeled from radiosonde and gridded analysis. Radiosonde-equivalent observation accuracy is demonstrated for radiometer neural network temperature and humidity retrievals up to 800 m height and for variational retrievals that combine radiometer and gridded analysis up to 10 km height« less

Computational fluid dynamics modeling of transport and deposition of pesticides in an aircraft cabin

PubMed Central

Isukapalli, Sastry S.; Mazumdar, Sagnik; George, Pradeep; Wei, Binnian; Jones, Byron; Weisel, Clifford P.

2015-01-01

Spraying of pesticides in aircraft cabins is required by some countries as part of a disinsection process to kill insects that pose a public health threat. However, public health concerns remain regarding exposures of cabin crew and passengers to pesticides in aircraft cabins. While large scale field measurements of pesticide residues and air concentrations in aircraft cabins scenarios are expensive and time consuming, Computational Fluid Dynamics (CFD) models provide an effective alternative for characterizing concentration distributions and exposures. This study involved CFD modeling of a twin-aisle 11 row cabin mockup with heated manikins, mimicking a part of a fully occupied Boeing 767 cabin. The model was applied to study the flow and deposition of pesticides under representative scenarios with different spraying patterns (sideways and overhead) and cabin air exchange rates (low and high). Corresponding spraying experiments were conducted in the cabin mockup, and pesticide deposition samples were collected at the manikin’s lap and seat top for a limited set of five seats. The CFD model performed well for scenarios corresponding to high air exchange rates, captured the concentration profiles for middle seats under low air exchange rates, and underestimated the concentrations at window seats under low air exchange rates. Additionally, both the CFD and experimental measurements showed no major variation in deposition characteristics between sideways and overhead spraying. The CFD model can estimate concentration fields and deposition profiles at very high resolutions, which can be used for characterizing the overall variability in air concentrations and surface loadings. Additionally, these model results can also provide a realistic range of surface and air concentrations of pesticides in the cabin that can be used to estimate potential exposures of cabin crew and passengers to these pesticides. PMID:25642134

Electrochemistry and capillary condensation theory reveal the mechanism of corrosion in dense porous media.

PubMed

Stefanoni, Matteo; Angst, Ueli M; Elsener, Bernhard

2018-05-09

Corrosion in carbonated concrete is an example of corrosion in dense porous media of tremendous socio-economic and scientific relevance. The widespread research endeavors to develop novel, environmentally friendly cements raise questions regarding their ability to protect the embedded steel from corrosion. Here, we propose a fundamentally new approach to explain the scientific mechanism of corrosion kinetics in dense porous media. The main strength of our model lies in its simplicity and in combining the capillary condensation theory with electrochemistry. This reveals that capillary condensation in the pore structure defines the electrochemically active steel surface, whose variability upon changes in exposure relative humidity is accountable for the wide variability in measured corrosion rates. We performed experiments that quantify this effect and find good agreement with the theory. Our findings are essential to devise predictive models for the corrosion performance, needed to guarantee the safety and sustainability of traditional and future cements.

Mask humidity during CPAP: influence of ambient temperature, heated humidification and heated tubing.

PubMed

Nilius, Georg; Domanski, Ulrike; Schroeder, Maik; Woehrle, Holger; Graml, Andrea; Franke, Karl-Josef

2018-01-01

Mucosal drying during continuous positive airway pressure (CPAP) therapy is problematic for many patients. This study assessed the influence of ambient relative humidity (rH) and air temperature (T) in winter and summer on mask humidity during CPAP, with and without mask leak, and with or without heated humidification ± heated tubing. CPAP (8 and 12 cmH 2 O) without humidification (no humidity [nH]), with heated humidification controlled by ambient temperature and humidity (heated humidity [HH]) and HH plus heated tubing climate line (CL), with and without leakage, were compared in 18 subjects with OSA during summer and winter. The absolute humidity (aH) and the T inside the mask during CPAP were significantly lower in winter versus summer under all applied conditions. Overall, absolute humidity differences between summer and winter were statistically significant in both HH and CL vs. nH ( p < 0.05) in the presence and absence of mouth leak. There were no significant differences in aH between HH and CL. However, in-mask temperature during CL was higher ( p < 0.05) and rH lower than during HH. In winter, CPAP with CL was more likely to keep rH constant at 80% than CPAP without humidification or with standard HH. Clinically-relevant reductions in aH were documented during CPAP given under winter conditions. The addition of heated humidification, using a heated tube to avoid condensation is recommended to increase aH, which could be useful in CPAP users complaining of nose and throat symptoms.

Mask humidity during CPAP: influence of ambient temperature, heated humidification and heated tubing

PubMed Central

Nilius, Georg; Domanski, Ulrike; Schroeder, Maik; Woehrle, Holger; Graml, Andrea; Franke, Karl-Josef

2018-01-01

Purpose Mucosal drying during continuous positive airway pressure (CPAP) therapy is problematic for many patients. This study assessed the influence of ambient relative humidity (rH) and air temperature (T) in winter and summer on mask humidity during CPAP, with and without mask leak, and with or without heated humidification ± heated tubing. Methods CPAP (8 and 12 cmH2O) without humidification (no humidity [nH]), with heated humidification controlled by ambient temperature and humidity (heated humidity [HH]) and HH plus heated tubing climate line (CL), with and without leakage, were compared in 18 subjects with OSA during summer and winter. Results The absolute humidity (aH) and the T inside the mask during CPAP were significantly lower in winter versus summer under all applied conditions. Overall, absolute humidity differences between summer and winter were statistically significant in both HH and CL vs. nH (p < 0.05) in the presence and absence of mouth leak. There were no significant differences in aH between HH and CL. However, in-mask temperature during CL was higher (p < 0.05) and rH lower than during HH. In winter, CPAP with CL was more likely to keep rH constant at 80% than CPAP without humidification or with standard HH. Conclusion Clinically-relevant reductions in aH were documented during CPAP given under winter conditions. The addition of heated humidification, using a heated tube to avoid condensation is recommended to increase aH, which could be useful in CPAP users complaining of nose and throat symptoms. PMID:29750062

75 FR 28485 - Airworthiness Directives; Gulfstream Aerospace LP (Type Certificate Previously Held by Israel...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-21

... caution light CABIN DOOR signaling both MED Improper Closure and MED Inflatable Seal Failure into two separate lights: CABIN DOOR and CABIN DOOR SEAL. 2. Converting the separated CABIN DOOR Caution light into a Warning light by changing its color to red. Note: Aircraft Flight Manuals (AFM'S) refer to these...

Protecting log cabins from decay

Treesearch

R. M. Rowell; J. M. Black; L. R. Gjovik; W. C. Feist

1977-01-01

This report answers the questions most often asked of the Forest Service on the protection of log cabins from decay, and on practices for the exterior finishing and maintenance of existing cabins. Causes of stain and decay are discussed, as are some basic techniques for building a cabin that will minimize decay. Selection and handling of logs, their preservative...

Treated cabin acoustic prediction using statistical energy analysis

NASA Technical Reports Server (NTRS)

Yoerkie, Charles A.; Ingraham, Steven T.; Moore, James A.

1987-01-01

The application of statistical energy analysis (SEA) to the modeling and design of helicopter cabin interior noise control treatment is demonstrated. The information presented here is obtained from work sponsored at NASA Langley for the development of analytic modeling techniques and the basic understanding of cabin noise. Utility and executive interior models are developed directly from existing S-76 aircraft designs. The relative importance of panel transmission loss (TL), acoustic leakage, and absorption to the control of cabin noise is shown using the SEA modeling parameters. It is shown that the major cabin noise improvement below 1000 Hz comes from increased panel TL, while above 1000 Hz it comes from reduced acoustic leakage and increased absorption in the cabin and overhead cavities.

Dynamic Effective Mass of Granular Media

NASA Astrophysics Data System (ADS)

Hsu, Chaur-Jian; Johnson, David L.; Ingale, Rohit A.; Valenza, John J.; Gland, Nicolas; Makse, Hernán A.

2009-02-01

We develop the concept of frequency dependent effective mass, Mtilde (ω), of jammed granular materials which occupy a rigid cavity to a filling fraction of 48%, the remaining volume being air of normal room condition or controlled humidity. The dominant features of Mtilde (ω) provide signatures of the dissipation of acoustic modes, elasticity, and aging effects in the granular medium. We perform humidity controlled experiments and interpret the data in terms of a continuum model and a “trap” model of thermally activated capillary bridges at the contact points. The results suggest that attenuation of acoustic waves in granular materials can be influenced significantly by the kinetics of capillary condensation between the asperities at the contacts.

Measuring Humidity in Sealed Glass Encasements

NASA Technical Reports Server (NTRS)

West, James W.; Burkett, Cecil G.; Levine, Joel S.

2005-01-01

A technique has been devised for measuring the relative humidity levels in the protective helium/water vapor atmosphere in which the Declaration of Independence, the United States Constitution, and the Bill of Rights are encased behind glass panels on display at the National Archives in Washington, DC. The technique is noninvasive: it does not involve penetrating the encasements (thereby risking contamination or damage to the priceless documents) to acquire samples of the atmosphere. The technique could also be applied to similar glass encasements used to protect and display important documents and other precious objects in museums. The basic principle of the technique is straightforward: An encasement is maintained at its normal display or operating temperature (e.g., room temperature) while a portion of its glass front panel is chilled (see Figure 1) until condensed water droplets become visible on the inside of the panel. The relative humidity of the enclosed atmosphere can then be determined as a known function of the dew point, the temperature below which the droplets condense. Notwithstanding the straightforwardness of the basic principle, careful attention to detail is necessary to enable accurate determination of the dew point. In the initial application, the affected portion of the glass panel was cooled by contact with an aluminum plate that was cooled by a thermoelectric module, the exhaust heat of which was dissipated by a heat sink cooled by a fan. A thermocouple was used to measure the interior temperature of the aluminum plate, and six other thermocouples were used to measure the temperatures at six locations on the cooled outer surface of the glass panel (see Figure 2). Thermal grease was applied to the aluminum plate and the thermocouples to ensure close thermal contact. Power was supplied to the thermoelectric module in small increments, based on previous laboratory tests. A small flashlight and a magnifying glass were used to look for water droplets condensing on the inner surface of the glass. The temperature readings of the thermocouples were taken during cool-down and upon observing condensation. In determining the dew point, it was necessary to make a correction for the differences between the temperatures measured on the chilled outer surface of the glass and the temperature of the inner surface, where the condensation took place. The correction was derived from a laboratory test on a measurement setup that was nearly identical, except that the dew location on the inner surface was also instrumented with a thermocouple. The test showed that the temperature at the dew location on the inner surface of the glass panel was 0.9 C above the temperature determined from the measurements on the chilled outer surface of the panel.

Fort Bliss Standards for the Treatment of Historic Buildings

DTIC Science & Technology

2008-05-01

visual disparity between the two materials. Typical historical uses for sandstone included • Urban row houses, commercial buildings and churches...migration within walls due to interior condensation and humidity, va- por drive problems caused by furnace, bathroom and kitchen vents, and rising damp...Replacing Deteriorated Woodwork • Historic Exteriors: Preserving Wood • Preservation Brief #31: Mothballing Historic Buildings Pests can be

Intermediate water recovery system

NASA Technical Reports Server (NTRS)

Deckman, G.; Anderson, A. R. (Editor)

1973-01-01

A water recovery system for collecting, storing, and processing urine, wash water, and humidity condensates from a crew of three aboard a spacecraft is described. The results of a 30-day test performed on a breadboard system are presented. The intermediate water recovery system produced clear, sterile, water with a 96.4 percent recovery rate from the processed urine. Recommendations for improving the system are included.

Removal mechanisms of dew via self-propulsion off the gecko skin

PubMed Central

Watson, Gregory S.; Schwarzkopf, Lin; Cribb, Bronwen W.; Myhra, Sverre; Gellender, Marty; Watson, Jolanta A.

2015-01-01

Condensation resulting in the formation of water films or droplets is an unavoidable process on the cuticle or skin of many organisms. This process generally occurs under humid conditions when the temperature drops below the dew point. In this study, we have investigated dew conditions on the skin of the gecko Lucasium steindachneri. When condensation occurs, we show that small dew drops, as opposed to a thin film, form on the lizard's scales. As the droplets grow in size and merge, they can undergo self-propulsion off the skin and in the process can be carried away a sufficient distance to freely engage with external forces. We show that factors such as gravity, wind and fog provide mechanisms to remove these small droplets off the gecko skin surface. The formation of small droplets and subsequent removal from the skin may aid in reducing microbial contact (e.g. bacteria, fungi) and limit conducive growth conditions under humid environments. As well as providing an inhospitable microclimate for microorganisms, the formation and removal of small droplets may also potentially aid in other areas such as reduction and cleaning of some surface contaminants consisting of single or multiple aggregates of particles. PMID:25762647

Multilfiltration Bed Replacement (MFBR) System for the International Space Station using Aquaporin Membranes and Humidity Condensate Ersatz Wastewater

NASA Technical Reports Server (NTRS)

Shaw, Hali L.; Howard, Kevin; Flynn, Michael T.; Beeler, David; Kawashima, Brian; Andersen, Thomas A. E.; Kleinschmidt, Kim; Vogel, Jorg; Parodi, Jurek

2017-01-01

The Multifiltration Bed system in the International Space Station (ISS) Water Processor Assembly (WPA) needs to be improved by reducing or eliminating the usage rate of expendable media, removing dimethylsilanediol (DMSD), and reducing the overall system mass. The WPA contains two multifiltration beds, each with a mass of approximately 50 kg. Reducing the mass of the WPA is an important part of evolving the ISS system for future exploration missions. The Multifiltration Bed Replacement (MFBR) technology is based on biomimetic membranes, which derive their unique characteristics from aquaporins, or water channel proteins. Aquaporin membranes were commercialized by the company Aquaporin AS. Tests were conducted using the Aquaporin Inside Hollow Fiber Module to determine the maximum water recovery ratio and membrane life. Samples were analyzed for total organic carbon (TOC), DMSD, acetate, ions, and volatiles such as ethanol and acetone. The results indicate that at a 97.498.1 water recovery ratio, the membrane module can reject approximately 50 of the TOC and specific conductance using the simulated ISS MSFC humidity condensate ersatz. Additionally, the life of the membrane was determined to be a minimum of 7103 hours.

The washout of combustion-generated hydrogen chloride. [rocket exhaust raindrop scavenging quantification

NASA Technical Reports Server (NTRS)

Fenton, D. L.; Purcell, R. Y.; Hrdina, D.; Knutson, E. O.

1980-01-01

The coefficient for the washout from a rocket exhaust cloud of HCl generated by the combustion of an ammonium perchlorate-based solid rocket propellant such as that to be used for the Space Shuttle Booster is determined. A mathematical model of HCl scavenging by rain is developed taking into account rain droplet size, fall velocity and concentration under various rain conditions, partitioning of exhaust HCl between liquid and gaseous phases, the tendency of HCl to promote water vapor condensation and the concentration and size of droplets within the exhaust cloud. The washout coefficient is calculated as a function of total cloud water content, total HCl content at 100% relative humidity, condensation nuclei concentration and rain intensity. The model predictions are compared with experimental results obtained in scavenging tests with solid rocket exhaust and raindrops of different sizes, and the large reduction in washout coefficient at high relative humidities predicted by the model is not observed. A washout coefficient equal to 0.0000512 times the -0.176 power of the mass concentration of HCl times the 0.773 power of the rainfall intensity is obtained from the experimental data.

Environmental dust effects on aluminum surfaces in humid air ambient.

PubMed

Yilbas, Bekir Sami; Hassan, Ghassan; Ali, Haider; Al-Aqeeli, Nasser

2017-04-05

Environmental dusts settle on surfaces and influence the performance of concentrated solar energy harvesting devices, such as aluminum troughs. The characteristics of environmental dust and the effects of mud formed from the dust particles as a result of water condensing in humid air conditions on an aluminum wafer surface are examined. The dissolution of alkaline and alkaline earth compounds in water condensate form a chemically active mud liquid with pH 8.2. Due to gravity, the mud liquid settles at the interface of the mud and the aluminum surface while forming locally scattered patches of liquid films. Once the mud liquid dries, adhesion work to remove the dry mud increases significantly. The mud liquid gives rise to the formation of pinholes and local pit sites on the aluminum surface. Morphological changes due to pit sites and residues of the dry mud on the aluminum surface lower the surface reflection after the removal of the dry mud from the surface. The characteristics of the aluminum surface can address the dust/mud-related limitations of reflective surfaces and may have implications for the reductions in the efficiencies of solar concentrated power systems.

Environmental dust effects on aluminum surfaces in humid air ambient

PubMed Central

Yilbas, Bekir Sami; Hassan, Ghassan; Ali, Haider; Al-Aqeeli, Nasser

2017-01-01

Environmental dusts settle on surfaces and influence the performance of concentrated solar energy harvesting devices, such as aluminum troughs. The characteristics of environmental dust and the effects of mud formed from the dust particles as a result of water condensing in humid air conditions on an aluminum wafer surface are examined. The dissolution of alkaline and alkaline earth compounds in water condensate form a chemically active mud liquid with pH 8.2. Due to gravity, the mud liquid settles at the interface of the mud and the aluminum surface while forming locally scattered patches of liquid films. Once the mud liquid dries, adhesion work to remove the dry mud increases significantly. The mud liquid gives rise to the formation of pinholes and local pit sites on the aluminum surface. Morphological changes due to pit sites and residues of the dry mud on the aluminum surface lower the surface reflection after the removal of the dry mud from the surface. The characteristics of the aluminum surface can address the dust/mud-related limitations of reflective surfaces and may have implications for the reductions in the efficiencies of solar concentrated power systems. PMID:28378798

An ultrahigh-accuracy Miniature Dew Point Sensor based on an Integrated Photonics Platform.

PubMed

Tao, Jifang; Luo, Yu; Wang, Li; Cai, Hong; Sun, Tao; Song, Junfeng; Liu, Hui; Gu, Yuandong

2016-07-15

The dew point is the temperature at which vapour begins to condense out of the gaseous phase. The deterministic relationship between the dew point and humidity is the basis for the industry-standard "chilled-mirror" dew point hygrometers used for highly accurate humidity measurements, which are essential for a broad range of industrial and metrological applications. However, these instruments have several limitations, such as high cost, large size and slow response. In this report, we demonstrate a compact, integrated photonic dew point sensor (DPS) that features high accuracy, a small footprint, and fast response. The fundamental component of this DPS is a partially exposed photonic micro-ring resonator, which serves two functions simultaneously: 1) sensing the condensed water droplets via evanescent fields and 2) functioning as a highly accurate, in situ temperature sensor based on the thermo-optic effect (TOE). This device virtually eliminates most of the temperature-related errors that affect conventional "chilled-mirror" hygrometers. Moreover, this DPS outperforms conventional "chilled-mirror" hygrometers with respect to size, cost and response time, paving the way for on-chip dew point detection and extension to applications for which the conventional technology is unsuitable because of size, cost, and other constraints.

An ultrahigh-accuracy Miniature Dew Point Sensor based on an Integrated Photonics Platform

NASA Astrophysics Data System (ADS)

Tao, Jifang; Luo, Yu; Wang, Li; Cai, Hong; Sun, Tao; Song, Junfeng; Liu, Hui; Gu, Yuandong

2016-07-01

The dew point is the temperature at which vapour begins to condense out of the gaseous phase. The deterministic relationship between the dew point and humidity is the basis for the industry-standard “chilled-mirror” dew point hygrometers used for highly accurate humidity measurements, which are essential for a broad range of industrial and metrological applications. However, these instruments have several limitations, such as high cost, large size and slow response. In this report, we demonstrate a compact, integrated photonic dew point sensor (DPS) that features high accuracy, a small footprint, and fast response. The fundamental component of this DPS is a partially exposed photonic micro-ring resonator, which serves two functions simultaneously: 1) sensing the condensed water droplets via evanescent fields and 2) functioning as a highly accurate, in situ temperature sensor based on the thermo-optic effect (TOE). This device virtually eliminates most of the temperature-related errors that affect conventional “chilled-mirror” hygrometers. Moreover, this DPS outperforms conventional “chilled-mirror” hygrometers with respect to size, cost and response time, paving the way for on-chip dew point detection and extension to applications for which the conventional technology is unsuitable because of size, cost, and other constraints.

Description of concept and first feasibility test results of a life support subsystem of the Botany Facility based on water reclamation

NASA Technical Reports Server (NTRS)

Loeser, H. R.

1986-01-01

The Botany Facility allows the growth of higher plants and fungi over a period of 6 months maximum. It is a payload planned for the second flight of the Eureca platform around 1990. Major tasks of the Life Support Subsystem (LSS) of the Botany Facility include the control of the pressure and composition of the atmosphere within the plant/fungi growth chambers, control of the temperature and humidity of the air and the regulation of the soil water content within specified limits. Previous studies have shown that various LSS concepts are feasible ranging from heavy, simple and cheap to light, complex and expensive solutions. A summary of those concepts is given. A new approach to accomplish control of the temperature and humidity of the air within the growth chambers based on water reclamation is discussed. This reclamation is achieved by condensation with a heat pump and capillary transport of the condensate back into the soil of the individual growth chamber. Some analytical estimates are given in order to obtain guidelines for circulation flow rates and to determine the specific power consumption.

Amine Swingbed Payload Technology Demonstration

NASA Technical Reports Server (NTRS)

Sweterlitsch, Jeffrey

2014-01-01

The Amine Swingbed is an amine-based, vacuum-regenerated adsorption technology for removing carbon dioxide and humidity from a habitable spacecraft environment, and is the baseline technology for the Orion Program’s Multi-Purpose Crew Vehicle (MPCV). It uses a pair of interleaved-layer beds filled with SA9T, the amine sorbent, and a linear multiball valve rotates 270° back and forth to control the flow of air and vacuum to adsorbing and desorbing beds. One bed adsorbs CO2 and H2O from cabin air while the other bed is exposed to vacuum for regeneration by venting the CO2 and H2O. The two beds are thermally linked, so no additional heating or cooling is required. The technology can be applied to habitable environments where recycling CO2 and H2O is not required such as short duration missions.

[Preliminary ergonomic assessment of the work sites and living conditions for the crew on board the new t/h Ignacy Daszyński series of merchant ships].

PubMed

Weclawik, Z

1989-01-01

The author describes the new merchant ship series B545-OT, built at the Szczecin shipyard. The preliminary appraisal of this vessel was made during the trial trip in November 1987. The experimented ship is a universal and very modern cargo boat, type B545-OT, which meets the requirements of the international conventions with respect to the prevention of sea pollution by ships. As regards its construction and equipment, the vessel complies with all conditions and international conventions on safety, as well as on health and environment protection. A control and actuation system centralized in the engine-room assures the functioning without a direct supervision. The automatic functioning of mechanisms is followed-up by means of a computed alarm system. The living-rooms, the recreation spaces, the cabins, which secure to the crew comfortable conditions on the ship, are built in a modern style. Less successfully was solved the placement of the kitchen, the dining-room and the larder on the upper deck, near the entrance to the engine-room, entailing thus the danger of steam penetration from the latter. The conditioned air assures in the cabins and living-rooms a temperature of +20 degrees C and a relative humidity of 40-60 per cent. The designers and builders have not used all the possibilities of lowering the intensity of noise.

Space and motion perception and discomfort in air travel.

PubMed

Ramos, Renato T; de Mattos, Danielle A; Rebouças, J Thales S; Ranvaud, Ronald D

2012-12-01

The perception of comfort during air trips is determined by several factors. External factors like cabin design and environmental parameters (temperature, humidity, air pressure, noise, and vibration) interact with individual characteristics (anxiety traits, fear of flying, and personality) from arrival at the airport to landing at the destination. In this study, we investigated the influence of space and motion discomfort (SMD), fear of heights, and anxiety on comfort perception during all phases of air travel. We evaluated 51 frequent air travelers through a modified version of the Flight Anxiety Situations Questionnaire (FAS), in which new items were added and where the subjects were asked to report their level of discomfort or anxiety (not fear) for each phase of air travel (Chronbach's alpha = 0.974). Correlations were investigated among these scales: State-Trait Anxiety Inventory (STAI), Cohen's Acrophobia Questionnaire, and the Situational Characteristics Questionnaire (SitQ, designed to estimate SMD levels). Scores of SitQ correlated with discomfort in situations involving space and movement perception (Pearson's rho = 0.311), while discomfort was associated with cognitive mechanisms related to scores in the anxiety scales (Pearson's rho = 0.375). Anxiety traits were important determinants of comfort perception before and after flight, while the influence of SMD was more significant during the time spent in the aircraft cabin. SMD seems to be an important modulator of comfort perception in air travel. Its influence on physical well being and probably on cognitive performance, with possible effects on flight safety, deserves further investigation.

Cabin Air Quality On Board Mir and the International Space Station: A Comparison

NASA Technical Reports Server (NTRS)

Macatangay, Ariel; Perry, Jay L.

2007-01-01

The maintenance of the cabin atmosphere aboard spacecraft is critical not only to its habitability but also to its function. Ideally, air quality can be maintained by striking a proper balance between the generation and removal of contaminants. Both very dynamic processes, the balance between generation and removal can be difficult to maintain and control because the state of the cabin atmosphere is in constant evolution responding to different perturbations. Typically, maintaining a clean cabin environment on board crewed spacecraft and space habitats is the central function of the environmental control and life support (ECLS) system. While active air quality control equipment is deployed on board every vehicle to remove carbon dioxide, water vapor, and trace chemical components from the cabin atmosphere, perturbations associated with logistics, vehicle construction and maintenance, and ECLS system configuration influence the resulting cabin atmospheric quality. The air-quality data obtained from the International Space Station (ISS) and NASA-Mir programs provides a wealth of information regarding the maintenance of the cabin atmosphere aboard long-lived space habitats. A comparison of the composition of the trace chemical contaminant load is presented. Correlations between ground-based and in-flight operations that influence cabin atmospheric quality are identified and discussed, and observations on cabin atmospheric quality during the NASA-Mir expeditions and the International Space Station are explored.

Finite element modal analysis of a vehicle-borne lidar cabin

NASA Astrophysics Data System (ADS)

Chen, Yafeng; Liu, Qiuwu; Wang, Jie; Hu, Shunxing; Huang, Jian

2018-02-01

Using SolidWorks software, the finite element modal analysis of a vehicle-borne pollution monitoring lidar cabin is carried out. The lidar cabin for the integrated lidar can ensure that the lidar system has good maneuverability and can effectively monitor the emission of air pollution. Since lidar is an integrated system of optics, mechanism, electricity and calculation, the performance of the cabin is directly related to the safety of the equipment and the lidar to work properly. Firstly, the cubic structure is modeled to simulate the cubic structure. Then, the model of the cabin model is analyzed by using the simulation plug-in, and the first 10 modes and natural frequencies are analyzed and recorded. The calculation results show that the cabin is dominated by bending vibration, and the amplitude area is concentrated in the opening of some windows and doors on each board. Therefore, we should increase the number of reinforcement bars or the strength of the skeleton in the vicinity of the door and window. At the same time, to avoid the resonance and ensure the precision of the optical elements and the electrical components and avoid structural damage of the cabin, the incentive frequency should be keep away from the natural frequency of the cabin. The vehicle-borne lidar system has been put into operation, and the analysis results have direct meaning to the transport of the cabin and the normal work.

The Hygroscopic Condenser Humidifier. A new device for general use in anaesthesia and intensive care.

PubMed

Gedeon, A; Mebius, C

1979-01-01

The design and performance of the Hygroscopic Condenser Humidifier (HCH) are described. In principle the HCH consists of two parts, a conventional Heat-Moisture-Exchanger (HME) and a hygroscopic unit. The hygroscopic action is shown to improve the water retention efficiency of the device by about a factor of two as compared with optimal HME designs. As a result, humidification levels corresponding to around 80% relative humidity at 37 degrees C are obtained in the trachea and this is also achieved when completely dry gases are delivered to the patient. The unit can therefore be used for all procedures in anaesthesia and in intensive care.

RAWINPROC: Computer program for decommutating, interpreting, and interpolating Rawinsonde meteorological balloon sounding data

NASA Technical Reports Server (NTRS)

Staffanson, F. L.

1981-01-01

The FORTRAN computer program RAWINPROC accepts output from NASA Wallops computer program METPASS1; and produces input for NASA computer program 3.0.0700 (ECC-PRD). The three parts together form a software system for the completely automatic reduction of standard RAWINSONDE sounding data. RAWINPROC pre-edits the 0.1-second data, including time-of-day, azimuth, elevation, and sonde-modulated tone frequency, condenses the data according to successive dwells of the tone frequency, decommutates the condensed data into the proper channels (temperature, relative humidity, high and low references), determines the running baroswitch contact number and computes the associated pressure altitudes, and interpolates the data appropriate for input to ACC-PRD.

Nucleation time of nanoscale water bridges.

PubMed

Szoszkiewicz, Robert; Riedo, Elisa

2005-09-23

Water capillaries bind together grains of sand. They also can bind an atomic force microscope tip to a substrate. The kinetics of capillary condensation at the nanoscale is studied here using friction force microscopy. At 40% relative humidity we find that the meniscus nucleation times increase from 0.7 to 4.2 ms when the temperature decreases from 332 to 299 K. The nucleation times grow exponentially with the inverse temperature 1/T obeying an Arrhenius law. We obtain a nucleation energy barrier of 7.8 x 10(-20) J and an attempt frequency ranging between 4 and 250 GHz, in excellent agreement with theoretical predictions. These results provide direct experimental evidence that capillary condensation is a thermally activated phenomenon.

Impact of cabin environment on thermal protection system of crew hypersonic vehicle

NASA Astrophysics Data System (ADS)

Zhu, Xiao Wei; Zhao, Jing Quan; Zhu, Lei; Yu, Xi Kui

2016-05-01

Hypersonic crew vehicles need reliable thermal protection systems (TPS) to ensure their safety. Since there exists relative large temperature difference between cabin airflow and TPS structure, the TPS shield that covers the cabin is always subjected to a non-adiabatic inner boundary condition, which may influence the heat transfer characteristic of the TPS. However, previous literatures always neglected the influence of the inner boundary by assuming that it was perfectly adiabatic. The present work focuses on studying the impact of cabin environment on the thermal performance. A modified TPS model is created with a mixed thermal boundary condition to connect the cabin environment with the TPS. This helps make the simulation closer to the real situation. The results stress that cabin environment greatly influences the temperature profile inside the TPS, which should not be neglected in practice. Moreover, the TPS size can be optimized during the design procedure if taking the effect of cabin environment into account.

Simultaneous measurements of ozone outside and inside cabins of two B-747 airliners and a Gates Learjet business jet

NASA Technical Reports Server (NTRS)

Perkins, P. J.; Briel, D.

1978-01-01

The average amount of ozone measured in the cabins of two B-747 airliners varied from 40 percent to 80 percent of the atmospheric concentrations without special ozone destruction systems. A charcoal filter in the cabin air inlet system of one B-747 reduced the ozone to about 5 percent of the atmospheric concentration. A Learjet 23 was also instrumented with monitors to measure simultaneously the atmospheric and ozone concentrations. Results indicate that a significant portion of the atmospheric ozone is not destroyed in the pressurization system and remains in the aircraft cabin of the Learjet. For the two cabin configurations tested, the ozone retentions were 63 and 41 percent of the atmospheric ozone concentrations. Ozone concentrations measured in the cabin near the conditioned-air outlets were reduced only slightly from atmospheric ozone concentrations. It is concluded that a constant difference between ozone concentrations inside and outside the cabin does not exist.

A simplified method for assessing particle deposition rate in aircraft cabins

NASA Astrophysics Data System (ADS)

You, Ruoyu; Zhao, Bin

2013-03-01

Particle deposition in aircraft cabins is important for the exposure of passengers to particulate matter, as well as the airborne infectious diseases. In this study, a simplified method is proposed for initial and quick assessment of particle deposition rate in aircraft cabins. The method included: collecting the inclined angle, area, characteristic length, and freestream air velocity for each surface in a cabin; estimating the friction velocity based on the characteristic length and freestream air velocity; modeling the particle deposition velocity using the empirical equation we developed previously; and then calculating the particle deposition rate. The particle deposition rates for the fully-occupied, half-occupied, 1/4-occupied and empty first-class cabin of the MD-82 commercial airliner were estimated. The results show that the occupancy did not significantly influence the particle deposition rate of the cabin. Furthermore, the simplified human model can be used in the assessment with acceptable accuracy. Finally, the comparison results show that the particle deposition rate of aircraft cabins and indoor environments are quite similar.

Study of Fluid Cooling Loop System in Chinese Manned Spacecraft

NASA Astrophysics Data System (ADS)

Jiang, Jun; Xu, Jiwan; Fan, Hanlin; Huang, Jiarong

2002-01-01

change. To solve the questions, a fluid cooling loop system must be applied to Chinese manned spacecraft besides other conventional thermal control methods, such as thermal control coatings, multiplayer insulation blankets, heat pipes, electro-heating adjustment temperature devices, and so on. The paper will introduce the thermal design of inner and outer fluid loop including their constitution and fundamental, etc. The capability of heat transportation and the accuracy of control temperature for the fluid loop will be evaluated and analyzed. To insure the air temperature of sealed cabins within 21+/-4, the inlet liquid temperature of condensing heat exchanger needs to be controlled within 9+/-2. To insure this, the inlet liquid temperature of middle heat exchanger needs to be controlled within 8+/-1.8. The inlet temperature point is controlled by a subsidiary loop adjusting: when the computer receives feedbacks of the deviation and the variety rate of deviation from the controlled temperature point. It drives the temperature control valve to adjust the flow flux distribution between the main loop through radiator and the subsidiary loop which isn't through radiator to control the temperature of the mixed fluid within 8+/-1.8. The paper will also introduce thermal designs of key parts in the cooling loop, such as space radiators, heat exchangers and cooling plates. Thermal simulated tests on the ground and flight tests have been performed to verify correctness of thermal designs. rational and the loop system works order. It realizes the circulation of absorbing heat dissipation to the loop and transferring it to radiator then radiating it to space. (2) loop control system controls inlet temperature of middle heat exchanger within 8+/-1.8 under various thermal cases. Thermal design of the middle heat exchanger insures inlet temperature of condensing heat within 9+/-2. Thereby, the air temperature of sealed cabins is controlled within about 21+/-4 accurately. (3) The thermal designs of the key heat exchanging parts (such as radiator, heat exchangers and cooling plates) in the cooling loop are rational and effective, they meet the requirements of heat exchanging and assure the entire system work order.

Future Data Communication Architectures for Safety Critical Aircraft Cabin Systems

NASA Astrophysics Data System (ADS)

Berkhahn, Sven-Olaf

2012-05-01

The cabin of modern aircraft is subject to increasing demands for fast reconfiguration and hence flexibility. These demands require studies for new network architectures and technologies of the electronic cabin systems, which consider also weight and cost reductions as well as safety constraints. Two major approaches are in consideration to reduce the complex and heavy wiring harness: the usage of a so called hybrid data bus technology, which enables the common usage of the same data bus for several electronic cabin systems with different safety and security requirements and the application of wireless data transfer technologies for electronic cabin systems.

Ozone contamination in aircraft cabins: Objectives and approach

NASA Technical Reports Server (NTRS)

Perkins, P. J.

1979-01-01

Three panels were developed to solve the problem of ozone contamination in aircraft cabins. The problem is defined from direct in-flight measurements of ozone concentrations inside and outside airliners in their normal operations. Solutions to the cabin ozone problem are discussed under two areas: (1) flight planning to avoid high ozone concentrations, and (2) ozone destruction techniques installed in the cabin air systems.

In-flight cabin smoke control.

PubMed

Eklund, T I

1996-12-31

Fatal accidents originating from in-flight cabin fires comprise only about 1% of all fatal accidents in the civil jet transport fleet. Nevertheless, the impossibility of escape during flight accentuates the hazards resulting from low visibility and toxic gases. Control of combustion products in an aircraft cabin is affected by several characteristics that make the aircraft cabin environment unique. The aircraft fuselage is pressurized in flight and has an air distribution system which provides ventilation jets from the ceiling level air inlets running along the cabin length. A fixed quantity of ventilation air is metered into the cabin and air discharge is handled primarily by pressure controlling outflow valves in the rear lower part of the fuselage. Earlier airplane flight tests on cabin smoke control used generators producing minimally buoyant smoke products that moved with and served as a telltales for overall cabin ventilation flows. Analytical studies were done with localized smoke production to predict the percent of cabin length that would remain smoke-free during continuous generation. Development of a buoyant smoke generator allowed simulation of a fire plume with controllable simulated temperature and heat release rates. Tests on a Boeing 757, modified to allow smoke venting out through the top of the cabin, showed that the buoyant smoke front moved at 0.46m/s (1.5ft/sec) with and 0.27m/sec (0.9ft/sec) against, the axial ventilation airflow. Flight tests in a modified Boeing 727 showed that a ceiling level counterflow of about 0.55m/sec (1.8ft/sec) was required to arrest the forward movement of buoyant smoke. A design goal of 0.61m/s (2ft/sec) axial cabin flow would require a flow rate of 99m3/min (3500ft3/min) in a furnished Boeing 757. The current maximum fresh air cabin ventilation flow is 78m3/min (2756 ft3/min). Experimental results indicate that buoyancy effects cause smoke movement behaviour that is not predicted by traditional design analyses and flight test methodologies. Augmenting available ventilation for smoke control remains a design and safety challenge.

Multimodel evaluation of cloud phase transition using satellite and reanalysis data

NASA Astrophysics Data System (ADS)

Cesana, G.; Waliser, D. E.; Jiang, X.; Li, J.-L. F.

2015-08-01

We take advantage of climate simulations from two multimodel experiments to characterize and evaluate the cloud phase partitioning in 16 general circulation models (GCMs), specifically the vertical structure of the transition between liquid and ice in clouds. We base our analysis on the ratio of ice condensates to the total condensates (phase ratio, PR). Its transition at 90% (PR90) and its links with other relevant variables are evaluated using the GCM-Oriented Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation Cloud Product climatology, reanalysis data, and other satellite observations. In 13 of 16 models, the PR90 transition height occurs too low (6 km to 8.4 km) and at temperatures too warm (-13.9°C to -32.5°C) compared to observations (8.6 km, -33.7°C); features consistent with a lack of supercooled liquid with respect to ice above 6.5 km. However, this bias would be slightly reduced by using the lidar simulator. In convective regimes (more humid air and precipitation), the observed cloud phase transition occurs at a warmer temperature than for subsidence regimes (less humid air and precipitation). Only few models manage to roughly replicate the observed correlations with humidity (5/16), vertical velocity (5/16), and precipitation (4/16); 3/16 perform well for all these parameters (MPI-ESM, NCAR-CAM5, and NCHU). Using an observation-based Clausius-Clapeyron phase diagram, we illustrate that the Bergeron-Findeisen process is a necessary condition for models to represent the observed features. Finally, the best models are those that include more complex microphysics.

Building characteristics, indoor air quality and recurrent wheezing in very young children (BAMSE).

PubMed

Emenius, G; Svartengren, M; Korsgaard, J; Nordvall, L; Pershagen, G; Wickman, M

2004-02-01

This study was conducted to examine the impact of building characteristics and indoor air quality on recurrent wheezing in infants. We followed a birth cohort (BAMSE) comprising 4089 children, born in predefined areas of Stockholm, during their first 2 years of life. Information on exposures was obtained from parental questionnaires when the children were 2 months and on symptoms and diseases when the children were 1 and 2 years old. Children with recurrent wheezing, and two age-matched controls per case, were identified and enrolled in a nested case-control study. The homes were investigated and ventilation rate, humidity, temperature and NO2 measured. We found that living in an apartment erected after 1939, or in a private home with crawl space/concrete slab foundation were associated with an increased risk of recurrent wheezing, odds ratio (OR) 2.5 (1.3-4.8) and 2.5 (1.1-5.4), respectively. The same was true for living in homes with absolute indoor humidity >5.8 g/kg, OR 1.7 (1.0-2.9) and in homes where windowpane condensation was consistently reported over several years, OR 2.2 (1.1-4.5). However, air change rate and type of ventilation system did not seem to affect the risk. In conclusion, relatively new apartment buildings, single-family homes with crawl space/concrete slab foundation, elevated indoor humidity, and reported wintertime windowpane condensation were associated with recurrent wheezing in infants. Thus, improvements of the building quality may have potential to prevent infant wheezing.

In Situ Determination of the Water Condensation Mechanisms on Superhydrophobic and Superhydrophilic Titanium Dioxide Nanotubes.

PubMed

Macias-Montero, Manuel; Lopez-Santos, Carmen; Filippin, A Nicolas; Rico, Victor J; Espinos, Juan P; Fraxedas, Jordi; Perez-Dieste, Virginia; Escudero, Carlos; Gonzalez-Elipe, Agustin R; Borras, Ana

2017-07-05

One-dimensional (1D) nanostructured surfaces based on high-density arrays of nanowires and nanotubes of photoactive titanium dioxide (TiO 2 ) present a tunable wetting behavior from superhydrophobic to superhydrophilic states. These situations are depicted in a reversible way by simply irradiating with ultraviolet light (superhydrophobic to superhydrophilic) and storage in dark. In this article, we combine in situ environmental scanning electron microscopy (ESEM) and near ambient pressure photoemission analysis (NAPP) to understand this transition. These experiments reveal complementary information at microscopic and atomic level reflecting the surface wettability and chemical state modifications experienced by these 1D surfaces upon irradiation. We pay special attention to the role of the water condensation mechanisms and try to elucidate the relationship between apparent water contact angles of sessile drops under ambient conditions at the macroscale with the formation of droplets by water condensation at low temperature and increasing humidity on the nanotubes' surfaces. Thus, for the as-grown nanotubes, we reveal a metastable and superhydrophobic Cassie state for sessile drops that tunes toward water dropwise condensation at the microscale compatible with a partial hydrophobic Wenzel state. For the UV-irradiated surfaces, a filmwise wetting behavior is observed for both condensed water and sessile droplets. NAPP analyses show a hydroxyl accumulation on the as-grown nanotubes surfaces during the exposure to water condensation conditions, whereas the water filmwise condensation on a previously hydroxyl enriched surface is proved for the superhydrophilic counterpart.

Demonstration of Nautilus Centripetal Capillary Condenser Technology

NASA Technical Reports Server (NTRS)

Wheeler, RIchard; Tang, Linh; Wambolt, Spencer; Golliher, Eric; Agui, Juan

2016-01-01

This paper describes the results of a proof of concept effort for development of a Nautilus Centripetal Capillary Condenser (NCCC or NC3) used for microgravity compatible water recovery from moist air with integral passive phase separation. Removal of liquid condensate from the air stream exiting a condenser is readily performed here on Earth. In order to perform this function in space however, without gravity or mechanical action, other tactics including utilization of inertial, drag and capillary forces are required. Within the NC3, liquid water forms via condensation on cold condenser surfaces as humid air passes along multiple spiral channels, each in its own plane, all together forming a stacked plate assembly. Non-mechanical inertial forces are employed to transfer condensate, as it forms, via centripetal action to the outer perimeter of each channel. A V-shaped groove, constructed on this outer edge of the spiral channel, increases local capillary forces thereby retaining the liquid. Air drag then pulls the liquid along to a collection region near the center of the device. Dry air produced by each parallel spiral channel is combined in a common orthogonal, out-of-plane conduit passing down the axial center of the stacked device. Similarly, the parallel condensate streams are combined and removed from the condenser/separator through yet another out-of-plane axial conduit. NC3 is an integration of conventional finned condenser operation, combined with static phase separation and capillary transport phenomena. A Mars' transit mission would be a logical application for this technology where gravity is absent and the use of vibrating, energy-intensive, motor-driven centrifugal separators is undesired. Here a vapor stream from either the Heat Melt Compactor or the Carbon dioxide Reduction Assembly, for example, would be dried to a dew point of 10 deg using a passive NC3 condenser/separator with the precious water condensate recycled to the water bus.

Differences in physical workload between military helicopter pilots and cabin crew.

PubMed

Van den Oord, Marieke H A; Sluiter, Judith K; Frings-Dresen, Monique H W

2014-05-01

The 1-year prevalence of regular or continuous neck pain in military helicopter pilots of the Dutch Defense Helicopter Command (DHC) is 20%, and physical work exposures have been suggested as risk factors. Pilots and cabin crew perform different tasks when flying helicopters. The aims of the current study were to compare the exposures to physical work factors between these occupations and to estimate the 1-year prevalence of neck pain in military helicopter cabin crew members. A survey was completed by almost all available helicopter pilots (n = 113) and cabin crew members (n = 61) of the DHC. The outcome measures were self-reported neck pain and exposures to nine physical work factors. Differences in the proportions of helicopter pilots and cabin crew members reporting being often exposed to the particular physical factor were assessed with the χ(2) test. The 1-year prevalence of regular or continuous neck pain among cabin crew was 28%. Significantly more cabin crew members than pilots reported being often exposed to manual material handling, performing dynamic movements with their torsos, working in prolonged bent or twisted postures with their torsos and their necks, working with their arms raised and working in awkward postures. Often exposure to prolonged sitting and dynamic movements with the neck were equally reported by almost all the pilots and cabin crew members. Flight-related neck pain is prevalent in both military helicopter pilots and cabin crew members. The exposures to neck pain-related physical work factors differ between occupations, with the cabin crew members subjected to more factors. These results have implications for preventative strategies for flight-related neck pain.

Investigation of Condensing Ice Heat Exchangers for MTSA Technology Development

NASA Technical Reports Server (NTRS)

Padilla, Sebastian; Powers, Aaron; Ball, Tyler; Iacomini, Christie; Paul, Heather, L.

2008-01-01

Metabolic heat regenerated Temperature Swing Adsorption (MTSA) technology is being developed for thermal, carbon dioxide (CO2) and humidity control for a Portable Life Support Subsystem (PLSS). Metabolically-produced CO2 present in the ventilation gas of a PLSS is collected using a CO2selective adsorbent via temperature swing adsorption. The temperature swing is initiated through cooling to well below metabolic temperatures. Cooling is achieved with a sublimation heat exchanger using water or liquid carbon dioxide (LCO2) expanded below sublimation temperature when exposed to low pressure or vacuum. Subsequent super heated vapor, as well as additional coolant, is used to further cool the astronaut. The temperature swing on the adsorbent is then completed by warming the adsorbent with a separate condensing ice heat exchanger (CIHX) using metabolic heat from moist ventilation gas. The condensed humidity in the ventilation gas is recycled at the habitat. The water condensation from the ventilation gas is a significant heat transfer mechanism for the warming of the adsorbent bed because it represents as much as half of the energy potential in the moist ventilation gas. Designing a heat exchanger to efficiently transfer this energy to the adsorbent bed and allow the collection of the water is a challenge since the CIHX will operate in a temperature range from 210K to 280K. The ventilation gas moisture will first freeze and then thaw, sometimes existing in three phases simultaneously. A NASA Small Business Innovative Research (SBIR) Phase 1 contract was performed to investigate condensing and icing as applied to MTSA to enable higher fidelity modeling and assess the impact of geometry variables on CIHX performance for future CIHX design optimization. Specifically, a design tool was created using analytical relations to explore the complex, interdependent design space of a condensing ice heat exchanger. Numerous variables were identified as having nontrivial contributions to performance such as hydraulic diameter, heat exchanger effectiveness, ventilation gas mass flow rate and surface roughness. Using this tool, four test articles were designed and manufactured to map to a full MTSA subassembly (the adsorbent bed, the sublimation heat exchanger for cooling and the condensing ice heat exchanger for warming). The design mapping considered impacts due to CIHX geometry as well as subassembly impacts such as thermal mass and thermal resistance through the adsorbent bed. The test articles were tested at simulated PLSS ventilation loop temperature, moisture content and subambient pressure. Ice accumulation and melting were observed. Data and test observations were analyzed to identify drivers of the condensing ice heat exchanger performance. This paper will discuss the analytical models, the test article designs, and testing procedures. Testing issues will be discussed to better describe data and share lessons learned. Data analysis and subsequent conclusions will be presented.

Evaluating the Adsorptive Capabilites of Chemsorb 1000 and Chemsorb 1425

NASA Technical Reports Server (NTRS)

Mejia, Oscar Alberto Monje; Surma, Jan M.; Johnsey, Marissa; Melendez, Orlando

2014-01-01

The removal of trace contaminants from spacecraft cabin air is necessary for crew health and comfort during long duration space exploration missions. The air revitalization technologies used in these future exploration missions will evolve from current ISS ISS State-of-Art (SOA) and is being designed and tested by the Advanced Exploration Systems (AES) Program's Atmosphere Resource Recovery and Environmental Monitoring (ARREM) project. The ARREM project is working to mature optimum atmosphere revitalization and environmental monitoring system architectures to enable exploration beyond Lower Earth Orbit (LEO). The Air Revitalization Lab at KSC is one of six NASA field centers participating in the ARREM that specializes in adsorbent and catalyst characterization with simulated spacecraft gas streams using combinations of pressure, O2 partial pressure, CO2 partial pressure, and humidity that are representative of a range of anticipated cabin atmospheric conditions and loads. On board ISS, the Trace Contaminant Control Subassembly (TCCS) provides active control of trace contaminants from the cabin atmosphere utilizing physical adsorption, thermal catalytic oxidation, and chemical adsorption processes. High molecular weight contaminants and ammonia (NH3) are removed a granular activated carbon treated with approx. 10% by weight phosphoric acid (H3PO4) (B-S Type 3032 4×6 mesh), which is expendable and is periodically refurbished. The Type 3032 granular activated carbon bed is no longer commercially available and therefore it is important to characterize the efficiency and capacity of commercially available NH3 sorbents. This paper describes the characterization of two Molecular Products LTD activated carbons: Chemsorb 1000 and Chemsorb 1425. Untreated activated carbons (e.g. Chemsorb 1000) remove contaminants by physisorption, which concentrates the contaminant within the pores of the carbon while letting air to pass through the sorbent4. Low molecular weight or polar gases (e.g. HCl, SO2, formaldehyde, and NH3) are not removed by physisorption and typically require chemisorption for removal. Treated activated carbons (e.g. Chemsorb 1425) are impregnated with a a chemical agent (e.g. phosphoric acid) that reacts with those gases, converting them to solids or salts within the carbon and removes them from the air stream. This process occurs via neutralization or catalysis reactions and adsorption capacity is exhaustedwhen the available impregnated chemicals are consumed. Moisture affects removal performance since adsorption sites within the pores are filled with water. The performance of impregnated carbons may be enhanced by moisture content because the mechanisms of contaminant removal are chemical reactions that occur in reagents contained within the pores. The adsorptive capacity data (mol/kg) of Chemsorb 1000 and 1425 for gas mixtures (ethanol, acetone, toluene, acetaldehyde, dichloromethane, and xylene) was measured with 40% relative humidity at 23 deg C air temperature. The adsorptive capacity data (mol/kg) of Chemsorb 1425 was measured using NH3 gas streams.

Towards an Integrated Approach to Cabin Service English Curriculum Design: A Case Study of China Southern Airlines' Cabin Service English Training Course

ERIC Educational Resources Information Center

Xiaoqin, Liu; Wenzhong, Zhu

2016-01-01

This paper has reviewed the history of EOP (training) development and then illustrated the curriculum design of cabin service English training from the three perspectives of ESP, CLIL and Business Discourse. It takes the cabin crew English training of China Southern Airlines (CZ) as the case and puts forward an operational framework composed of…

Airliner cabin ozone : an updated review.

DOT National Transportation Integrated Search

1989-12-01

The recent literature pertaining to ozone contamination of airliner cabins is reviewed. Measurements in airliner cabins without filters showed that ozone levels were about 50 percent of atmospheric ozone. Filters were about 90 percent effective in de...

Heat and mass transfer of a low-pressure Mars greenhouse: Simulation and experimental analysis

NASA Astrophysics Data System (ADS)

Hublitz, Inka

Biological life support systems based on plant growth offer the advantage of producing fresh food for the crew during a long surface stay on Mars. Greenhouses on Mars are also used for air and water regeneration and waste treatment. A major challenge in developing a Mars greenhouse is its interaction with the thin and cold Mars environment. Operating a Mars greenhouse at low interior pressure reduces the pressure differential across the structure and therefore saves structural mass as well as reduces leakage. Experiments were conducted to analyze the heating requirements as well as the temperature and humidity distribution within a small-scale greenhouse that was placed in a chamber simulating the temperatures, pressure and light conditions on Mars. Lettuce plants were successfully grown inside of the Mars greenhouse for up to seven days. The greenhouse atmosphere parameters, including temperature, total pressure, oxygen and carbon dioxide concentration were controlled tightly; radiation level, relative humidity and plant evapo-transpiration rates were measured. A vertical stratification of temperature and humidity across the greenhouse atmosphere was observed. Condensation formed on the inside of the greenhouse when the shell temperature dropped below the dew-point. During the night cycles frost built up on the greenhouse base plate and the lower part of the shell. Heat loss increased significantly during the night cycle. Due to the placement of the heating system and the fan blowing warm air directly on the upper greenhouse shell, condensation above the plants was avoided and therefore the photosynthetically active radiation at plant level was kept constant. Plant growth was not affected by the temperature stratification due to the tight temperature control of the warmer upper section of the greenhouse, where the lettuce plants were placed. A steady state and a transient heat transfer model of the low pressure greenhouse were developed for the day and the night cycle. Furthermore, low pressure psychrometric relations for closed systems and modified atmospheres were generated to calculate the properties of the moist air in order to predict condensate formation. The results of this study improve the design of the environmental control system leading to an optimization of plant growth conditions.

Ice Nucleation of Soot Particles in the Cirrus Regime: Is Pore Condensation and Freezing Relevant for Soot?

NASA Astrophysics Data System (ADS)

Kanji, Z. A.; Mahrt, F.; David, R.; Marcolli, C.; Lohmann, U.; Fahrni, J.; Brühwiler, D.

2017-12-01

Heterogeneous ice nucleation (HIN) onto soot particles from previous studies have produced inconsistent results of temperature and relative humidity conditions required for freezing depending on the source of soot particle investigated. The ability of soot to act as HIN depended on the type of soot and size of particle. Often homogenous freezing conditions or water saturation conditions were required to freeze soot particles, rendering HIN irrelevant. Using synthesised mesoporous silica particles, we show pore condensation and freezing works with experiments performed in the Zurich Ice Nucleation Chamber (ZINC). By testing a variety of soot particles in parallel in the Horizontal Ice Nucleation Chamber (HINC), we suggest that previously observed HIN on soot particles is not the responsible mechanism for ice formation. Laboratory generated CAST brown and black soot, commercially available soot and acid treated soot were investigated for their ice nucleation abilities in the mixed-phase and cirrus cloud temperature regimes. No heterogeneous ice nucleation activity is inferred at T > -38 °C (mixed-phase cloud regime), however depending on particle size and soot type, HIN was observed for T < -38 °C (cirrus could regime). Nevertheless, we question if this is caused by a heterogeneous phase change due the presence of a so called active site or due to pore-condensation of water as predicted by the inverse Kelvin effect followed by homogeneous nucleation of ice in the pores or cavities that are ubiquitous in soot particles between the primary spherules. The ability of some particles to freeze at lower relative humidity compared to others demonstrates why hydrophobicity plays a role in ice nucleation, i.e. controlling the conditions at which these cavities fill with water. Thus for more hydrophobic particles pore filling occurs at higher relative humidity, and therefore freezing of pore water and ice crystal growth. Future work focusses on testing the cloud processing ability of soot particles and water adsorption isotherms of the different soot samples to support the hydrophobicity inferences from the ice nucleation results.

Dual direction blower system powered by solar energy to reduce car cabin temperature in open parking condition

NASA Astrophysics Data System (ADS)

Hamdan, N. S.; Radzi, M. F. M.; Damanhuri, A. A. M.; Mokhtar, S. N.

2017-10-01

El-nino phenomenon that strikes Malaysia with temperature recorded more than 35°C can lead to extreme temperature rise in car cabin up to 80°C. Various problems will arise due to this extreme rising of temperature such as the occupant are vulnerable to heat stroke, emission of benzene gas that can cause cancer due to reaction of high temperature with interior compartments, and damage of compartments in the car. The current solution available to reduce car cabin temperature including tinted of window and portable heat rejection device that are available in the market. As an alternative to reduce car cabin temperature, this project modifies the car’s air conditioning blower motor into dual direction powered by solar energy and identifies its influence to temperature inside the car, parked under scorching sun. By reducing the car cabin temperature up to 10°C which equal to 14% of reduction in the car cabin temperature, this simple proposed system aims to provide comfort to users due to its capability in improving the quality of air and moisture in the car cabin.

Effects of aircraft cabin noise on passenger comfort.

PubMed

Pennig, Sibylle; Quehl, Julia; Rolny, Vinzent

2012-01-01

The effects of cabin noise on subjective comfort assessments were systematically investigated in order to reveal optimisation potentials for an improved passenger noise acceptance. Two aircraft simulation studies were conducted. An acoustic laboratory test facility provided with loudspeaker systems for realistic sound presentations and an aircraft cabin simulator (Dornier Do 728) with a high degree of ecological validity were used. Subjects were exposed to nine different noise patterns (three noise levels ranging from 66 to 78 dB(A) combined with three different frequency spectra). Regression analysis demonstrated a significant increase of passengers' acceptance with lower noise levels and significant effects of different frequency spectra determined by seat position in the aircraft cabin (front, middle, rear). Acoustic cabin design should therefore consider measures beyond noise level reduction altering noise characteristics to improve passengers' comfort and well-being in the aircraft cabin. To improve passenger comfort in the aircraft with respect to cabin noise, passengers' reactions to specific noise conditions were systematically investigated. Two laboratory studies showed significant dose-response relationships between sound pressure level and subjective comfort ratings which differed due to the noise at specific seat positions in the aircraft.

NASA Global Atmospheric Sampling Program (GASP) data report for tape VL0015, VL0016, VL0017, VL0018, VL0019, and VL0020

NASA Technical Reports Server (NTRS)

Papthakos, L. C.; Briehl, D.

1981-01-01

This is the twelfth of a series of reports which describes the data currently available from GASP, including flight routes and dates, instrumentation, data processing procedures, and data tape specifications. In-situ measurements of atmospheric ozone, cabin ozone, carbon monoxide, water vapor, particles, clouds, condensation nuclei, filter samples and related meteorological and flight information obtained during 1732 flights of aircraft N533PA, N4711U, N655PA, and VH-EBE from January 5, 1978 through October 9, 1978 are reported. These data are now available from the National Climatic Center, Asheville, NC, 22801. In addition to the GASP data, tropopause pressures obtained from time ans space interpolation of National Meteorological Center archived data for the dates of the flights are included.

Computer image processing of up-draft flow motion and severe storm formation observed from satellite

NASA Technical Reports Server (NTRS)

Hung, R. J.; Smith, R. E.

1985-01-01

Special rapid-scan satellite visible and infrared observations have been used to study the life cycle of the clouds from the initiation of updraft flow motion in the atmosphere, the condensation of humid air, the formation of clouds, the development of towering cumulus, the penetration of the tropopause, the collapsing of an overshooting turret, and the dissipation of cloud. The infrared image provides an indication of the equivalent blackbody temperature of the observed cloud tops. By referencing the temperature, height and humidity profiles from rawinsonde observations as the background meteorological data for the instability of the air mass to the satellite infrared data sets at different time periods, the development of convective clouds can be studied in detail.

Computational Fluid Dynamic Analysis of Enhancing Passenger Cabin Comfort Using PCM

NASA Astrophysics Data System (ADS)

Purusothaman, M.; Valarmathi, T. N.; Dada Mohammad, S. K.

2016-09-01

The main purpose of this study is to determine a cost effective way to enhance passenger cabin comfort by analyzing the effect of solar radiation of a open parked vehicle, which is exposed to constant solar radiation on a hot and sunny day. Maximum heat accumulation occurs in the car cabin due to the solar radiation. By means of computational fluid dynamics (CFD) analysis, a simulation process is conducted for the thermal regulation of the passenger cabin using a layer of phase change material (PCM) on the roof structure of a stationary car when exposed to ambient temperature on a hot sunny day. The heat energy accumulated in the passenger cabin is absorbed by a layer of PCM for phase change process. The installation of a ventilation system which uses an exhaust fan to create a natural convection scenario in the cabin is also considered to enhance passenger comfort along with PCM.

Human Mars Ascent Vehicle Configuration and Performance Sensitivities

NASA Technical Reports Server (NTRS)

Polsgrove, Tara P.; Thomas, Herbert D.; Stephens, Walter; Collins, Tim; Rucker, Michelle; Gernhardt, Mike; Zwack, Matthew R.; Dees, Patrick D.

2017-01-01

The total ascent vehicle mass drives performance requirements for the Mars descent systems and the Earth to Mars transportation elements. Minimizing Mars Ascent Vehicle (MAV) mass is a priority and minimizing the crew cabin size and mass is one way to do that. Human missions to Mars may utilize several small cabins where crew members could live for days up to a couple of weeks. A common crew cabin design that can perform in each of these applications is desired and could reduce the overall mission cost. However, for the MAV, the crew cabin size and mass can have a large impact on vehicle design and performance. This paper explores the sensitivities to trajectory, propulsion, crew cabin size and the benefits and impacts of using a common crew cabin design for the MAV. Results of these trades will be presented along with mass and performance estimates for the selected design.

Measurements of upper troposheric humidity at low temperatures during CRYSTAL-FACE

NASA Technical Reports Server (NTRS)

Herman, Robert L.; Heymsfield, Andrew J.; Ridley, Brian A.; Bui, Paul T.

2003-01-01

Aircraft condensation trails (contrails) and thin cirrus were studied by instruments on the NASA WB-57F high-altitude aircraft during contrails and optically thing cirrus are contrasted by different levels of supersaturation with respect to ice. During the July 13, 2002, flight of the WB-57F aircraft intercepted visible contrails produced by both the WB-57F and ER-2 aircraft. These contrails were located immediately below the local tropopause, where ambient temperatures were very low (-76 degree C). The contrails were clearly indicated by an abrupt increase in NO and a simultaneous, abrupt decrease in ice supersaturation. With in the contrail, the relative humidity was close to 130% with respect to ice, higher than expected from theory. Outside the contrails was a persistent layer of subvisible currus extending from approximately 13 to 15 km altitude. This layer was characterized y significant supersaturations because the ambient concentrations of ice particles were insufficient to significantly deplete the ice supersaturation. We will discuss in situ measurements and models simulations of humidity.

Kinetics of moisture-induced hydrolysis in powder blends stored at and below the deliquescence relative humidity: investigation of sucrose-citric acid mixtures.

PubMed

Kwok, Kaho; Mauer, Lisa J; Taylor, Lynne S

2010-11-24

Previous studies have shown that deliquescent organic compounds frequently exhibit chemical instability when stored in environmental conditions above their deliquescence relative humidity (RH). The goal of the current study was to investigate the effect of atmospheric moisture on the long-term chemical stability of crystalline sucrose-citric acid mixtures following storage at RHs at and below the mutual deliquescence relative humidity (MDRH). Interestingly, it was found that sucrose hydrolysis can occur below the MDRH of 64% and was observed for samples stored at 54% RH. However, hydrolysis was not seen for samples stored at 33 or 43% RH. The rate of sucrose hydrolysis could be modeled by taking into account the rate and extent of moisture uptake, which in turn was dependent on the composition of the powder and the storage RH. A reaction mechanism initiated by capillary condensation and involving additional deliquescence lowering by the degradation products formed as a result of sucrose hydrolysis (glucose and fructose) was proposed.

Experimental evidence supporting the insensitivity of cloud droplet formation to the mass accommodation coefficient for condensation of water vapor to liquid water

NASA Astrophysics Data System (ADS)

Langridge, Justin M.; Richardson, Mathews S.; Lack, Daniel A.; Murphy, Daniel M.

2016-06-01

The mass accommodation coefficient for uptake of water vapor to liquid water, αM, has been constrained using photoacoustic measurements of aqueous absorbing aerosol. Measurements performed over a range of relative humidities and pressures were compared to detailed model calculations treating coupled heat and mass transfer occurring during photoacoustic laser heating cycles. The strengths and weaknesses of this technique are very different to those for droplet growth/evaporation experiments that have typically been applied to these measurements, making this a useful complement to existing studies. Our measurements provide robust evidence that αM is greater than 0.1 for all humidities tested and greater than 0.3 for data obtained at relative humidities greater than 88% where the aerosol surface was most like pure water. These values of αM are above the threshold at which kinetic limitations are expected to impact the activation and growth of aerosol particles in warm cloud formation.

Anthropometric assessment of crane cabins and recommendations for design: A case study.

PubMed

Zunjic, Aleksandar; Brkic, Vesna Spasojevic; Klarin, Milivoj; Brkic, Aleksandar; Krstic, Dragan

2015-01-01

Work of crane operators is very difficult and demanding. Therefore, it is very important that the cabin of a crane be designed on the basis of relevant anthropometric data. However, it is very difficult to find a research that considers anthropometric convenience of crane cabins. From the theoretical viewpoint, it is important to perceive and to classify effects of the anthropometric incompatibility of crane cabins. Globally, the objective is to consider the anthropometric convenience of existing crane cabins, and possibilities for improvements of their design from the ergonomic point of view. In this regard, it is significant to detect constraints that impede or hinder the work of the crane operators, which could be overcome with certain anthropometric solutions. The main objective is to examine whether and to what extent is justifiable to use anthropometric data that are obtained on the basis of general (national) population, during designing the crane cabins. For the assessment of existing crane cabins and the work of operators, four methods were used: observation of the work of the operators and design solutions of the cabins, the checklist approach, interviewing of operators and the experimental research based on obtaining the data on the population of crane operators. Results of the analysis based on the method of observation, analysis based on the application of the checklist, as well as interviewing of the operators indicate that certain construction constraints of the components in the cabins are the main reasons of reduced visibility and improper working postures of operators. All this has caused the emergence of continuous musculoskeletal loading of the crane operators. The results of the anthropometric research that were obtained on the population of crane operators in this case study suggest that there is a statistically significant difference, when compared data of this population of workers with anthropometric data from the general population. Analyzed workplaces in crane cabins do not correspond to the majority of operators from the anthropometric standpoint. The conducted anthropometric analysis has been indicated that could be made the mistake, if dimensions of the cabin and layout of equipment would be relied on data derived from the general population of citizens. In order to achieve greater precision in the design and configuration of equipment, it is recommended using the data that are obtained directly on the population of the crane operators when designing the cabin.

Integrated Cabin and Fuel Cell System Thermal Management with a Metal Hydride Heat Pump

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hovland, V.

2004-12-01

Integrated approaches for the heating and cooling requirements of both the fuel cell (FC) stack and cabin environment are critical to fuel cell vehicle performance in terms of stack efficiency, fuel economy, and cost. An integrated FC system and cabin thermal management system would address the cabin cooling and heating requirements, control the temperature of the stack by mitigating the waste heat, and ideally capture the waste heat and use it for useful purposes. Current work at the National Renewable Energy Laboratory (NREL) details a conceptual design of a metal hydride heat pump (MHHP) for the fuel cell system andmore » cabin thermal management.« less

Hygroscopic condenser humidifier as a solution to nasal dryness due to nasal CPAP treatment for obstructive sleep apnea syndrome.

PubMed

Parra, O; Klamburg, J; Xirgu, J; Abad, J; Sala, H; Tomasa, A; Morera, J

1991-04-01

We report an apparent solution to nasal dryness for patients with obstructive sleep apnea syndrome treated with nasal continuous positive airway pressure (CPAP) when a hygroscopic condenser humidifier is introduced into the CPAP circuit. Six patients underwent a 5-h test period of nasal CPAP therapy with a mask containing a hygroscopic humidifier. The water vapor showed a statistically significant increase in both inspired and expired gases. The relative humidity of the inspired gases increased significantly. The levels of O2 and CO2 in the respired gases did not change. When patients were asked about nasal dryness at the end of the test, all of them reported marked improvement.

Microbial Characterization of Free Floating Condensate Aboard the Mir Space Station

NASA Technical Reports Server (NTRS)

Ott, C. M.; Bruce, R. J.; Pierson, D. L.

2004-01-01

Three samples of humidity condensate that had accumulated behind panels aboard the Russian space station Mir were collected and returned to earth for analysis. As these floating masses of liquid come into contact with the astronauts and the engineering systems, they have the potential to affect both crew health and systems performance. Using a combination of culturing techniques, a wide variety of organisms were isolated included Escherichia coli, Serratia marcescens, and a presumed Legionella species. In addition, microscopic analysis indicated the presence of protozoa, dust mites, and spirochetes. These findings suggest the need for more comprehensive microbial analysis of the environment through the use of new methodologies to allow a more thorough risk assessment of spacecraft. Copyright 2004 Springer-Verlag.

Assessment of Cabin Dimensions to Accommodate Infantry Soldiers for the Future Vertical Lift/Joint Multi-Role Medium-Class Aircraft

DTIC Science & Technology

2014-07-01

an official Department of the Army position unless so designated by other authorized documents. Citation of manufacturer’s or trade names does...The dimensions assessed included seat space widths, cabin ceiling heights, aisle widths, seating configurations, and cabin door widths. Emergency... seat spacing, 66-in. cabin ceiling height, 72-in. floor width, and 32-in. door width. These dimensions will help ensure that Soldiers have adequate

Experimental studies of thermal environment and contaminant transport in a commercial aircraft cabin with gaspers on.

PubMed

Li, B; Duan, R; Li, J; Huang, Y; Yin, H; Lin, C-H; Wei, D; Shen, X; Liu, J; Chen, Q

2016-10-01

Gaspers installed in commercial airliner cabins are used to improve passengers' thermal comfort. To understand the impact of gasper airflow on the air quality in a cabin, this investigation measured the distributions of air velocity, air temperature, and gaseous contaminant concentration in five rows of the economy-class section of an MD-82 commercial aircraft. The gaseous contaminant was simulated using SF6 as a tracer gas with the source located at the mouth of a seated manikin close to the aisle. Two-fifths of the gaspers next to the aisle were turned on in the cabin, and each of them supplied air at a flow rate of 0.66 l/s. The airflow rate in the economy-class cabin was controlled at 10 l/s per passenger. Data obtained in a previous study of the cabin with all gaspers turned off were used for comparison. The results show that the jets from the gaspers had a substantial impact on the air velocity and contaminant transport in the cabin. The air velocity in the cabin was higher, and the air temperature slightly more uniform, when the gaspers were on than when they were off, but turning on the gaspers may not have improved the air quality. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

3. View from behind (D) fourroom cabin, showing relationship between ...

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

3. View from behind (D) four-room cabin, showing relationship between it and l(A) mansion. View looking north-northeast. - Fort Hill Farm, Four-Room Cabin, West of Staunton (Roanoke) River between Turkey & Caesar's Runs, Clover, Halifax County, VA

Advancements in oxygen generation and humidity control by water vapor electrolysis

NASA Technical Reports Server (NTRS)

Heppner, D. B.; Sudar, M.; Lee, M. C.

1988-01-01

Regenerative processes for the revitalization of manned spacecraft atmospheres or other manned habitats are essential for realization of long-term space missions. These processes include oxygen generation through water electrolysis. One promising technique of water electrolysis is the direct conversion of the water vapor contained in the cabin air to oxygen. This technique is the subject of the present program on water vapor electrolysis development. The objectives were to incorporate technology improvements developed under other similar electrochemical programs and add new ones; design and fabricate a mutli-cell electrochemical module and a testing facility; and demonstrate through testing the improvements. Each aspect of the water vapor electrolysis cell was reviewed. The materials of construction and sizing of each element were investigated analytically and sometime experimentally. In addition, operational considerations such as temperature control in response to inlet conditions were investigated. Three specific quantitative goals were established.

Technology advancement of the electrochemical CO2 concentrating process

NASA Technical Reports Server (NTRS)

Schubert, F. H.; Woods, R. R.; Hallick, T. M.; Heppner, D. B.

1978-01-01

The overall objectives of the present program are to: (1) improve the performance of the electrochemical CO2 removal technique by increasing CO2 removal efficiencies at pCO2 levels below 400 Pa, increasing cell power output and broadening the tolerance of electrochemical cells for operation over wide ranges of cabin relative humidity; (2) design, fabricate, and assemble development hardware to continue the evolution of the electrochemical concentrating technique from the existing level to an advanced level able to efficiently meet the CO2 removal needs of a spacecraft air revitalization system (ARS); (3) develop and incorporate into the EDC the components and concepts that allow for the efficient integration of the electrochemical technique with other subsystems to form a spacecraft ARS; (4) combine ARS functions to enable the elimination of subsystem components and interfaces; and (5) demonstrate the integration concepts through actual operation of a functionally integrated ARS.

Experimental investigation of thermal comfort and air quality in an automobile cabin during the cooling period

NASA Astrophysics Data System (ADS)

Kilic, M.; Akyol, S. M.

2012-08-01

The air quality and thermal comfort strongly influenced by the heat and mass transfer take place together in an automobile cabin. In this study, it is aimed to investigate and assess the effects of air intake settings (recirculation and fresh air) on the thermal comfort, air quality satisfaction and energy usage during the cooling period of an automobile cabin. For this purpose, measurements (temperature, air velocity, CO2) were performed at various locations inside the cabin. Furthermore, whole body and local responses of the human subjects were noted while skin temperatures were measured. A mathematical model was arranged in order to estimate CO2 concentration and energy usage inside the vehicle cabin and verified with experimental data. It is shown that CO2 level inside of the cabin can be greater than the threshold value recommended for the driving safety if two and more occupants exist in the car. It is also shown that an advanced climate control system may satisfy the requirements for the air quality and thermal comfort as well as to reduce the energy usage for the cooling of a vehicle cabin.

Don`t sweat it, dehumidify

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harriman, L.; Simkins, D.

Beads of perspiration dripping from pipes and valves are a nuisance to mop up, but they are a telltale sign of the problems that excess humidity can cause. Fluctuations in the delicate balance of temperature and moisture in process environments are often the culprit for the corrosion, condensation, and clogging and sticking that bottlenecks plant operations and slows down production. Dehumidification is used to prevent moisture regain, condensation and corrosion, and to promote the drying of heat-sensitive products. There are three methods for removing moisture from air: Squeeze out water by increasing the pressure; though commonly used for compressed airmore » and other applications at elevated pressures, it is virtually never used to remove moisture in atmospheric pressure applications. Compressor equipment and operating costs are prohibitive, compared with those for conventional methods for dehumidifying air at ambient pressures; Condense water by chilling the surrounding air; and Pull out water by passing air across the surface of a desiccant. The paper discusses desiccation versus cooling, system design, and project management.« less

Engineering evaluation of the use of the Timberline condensing economizer for particulate collection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Butcher, T.; Serry, H.

1980-12-01

The possible use of the Timberline Industries condensing economizer as a particulate collection device on commercial sector boilers which are being converted to coal-oil mixture (COM) firing has been considered. The saturation temperature of the water vapor in the flue gas has been estimated as a function of excess air and ambient relative humidity. Also, boiler stack losses have been estimated for a variety of operating conditions including stack temperatures below the dew point. The condensing economizer concept will be limited to applications which can use the low temperature heat including water heating and forced air space heating. The potentialmore » particulate collection efficiency, water disposal, and similar heat recovery devices are discussed. A cost analysis is presented which indicates that the economizer system is not competitive with a cyclone but is competitive with a baghouse. The use of the cyclone is limited by collection efficiency. The measurement of COM flyash particle size distribution is recommended.« less

Test results from a comparative evaluation of a condensation nuclei fire detector

NASA Technical Reports Server (NTRS)

Bricker, R. W.

1985-01-01

The fire/smoke alarm response of a condensation nuclei fire detector (CNFD) was compared with photoelectric and ionization detectors. Tests were conducted in a former control room 8.5 m by 8.9 with a 2.7 m ceiling. The room had air supplied from above the ceiling and under the floor with return air exiting from ceiling grills. The environment was varied from 278 to 305 K and relative humidities from 8 to 65%. Four detection zones were located in the room. Each zone contained a sampling head for the CNDF, a photodetector, and an ionization detector so that each detector system had four opportunities to alarm during tests. The particle level in the test room was also monitored during tests with a condensation nuclei particle counter. The CNFD responded to 90% of exposures to smoldering plastic and 84% of exposures to visible fire. The photoelectric response was 43 and 12.5% respectively for the same conditions. The ionization response was 9 and 48 respectively.

Do the components of heat and moisture exchanger filters affect their humidifying efficacy and the incidence of nosocomial pneumonia?

PubMed

Thomachot, L; Vialet, R; Arnaud, S; Barberon, B; Michel-Nguyen, A; Martin, C

1999-05-01

To compare the efficiency of two heat and moisture exchange filters (HMEFs) of different compositions of the humidifying capacity and the rate of bronchial colonization and ventilator-associated pneumonia in patients in the intensive care unit (ICU). Prospective, randomized study. ICU of a university hospital. All patients who required mechanical ventilation for 24 hrs or more during the study period. At admission to the ICU, patients were randomly assigned to one of two groups. In one group, the patients were ventilated with Humid-Vent Filter Light HMEF. The condensation surface was made of paper impregnated with CaCl2. The filter membrane was made of polypropylene. In the other group, the patients were ventilated with the Clear ThermAl HMEF (Intersurgical, France). The condensation surface was made of plastic foam impregnated with AlCl2. The filter membrane was made of two polymer fibers (modacrylic and polypropylene). In both groups, HMEFs were changed daily. Seventy-seven patients were ventilated for 19+/-7 days with the Humid-Vent Filter Light HMEF and 63 patients for 17+/-6 days with the Clear ThermAl HMEF. Patients ventilated with the Humid-Vent Filter Light underwent 8.7+/-3.7 tracheal aspirations and 1.2+/-2.0 instillations per day and those with the Clear ThermAl, 8.2+/-3.9 and 1.5+/-2.4 per day, respectively (NS). The abundance of tracheal secretions and the presence of blood and viscosity, as evaluated by semiquantitative scales, were similar in both groups. One episode of tracheal tube occlusion was observed with the Humid-Vent Filter Light HMEF and none with the other HMEF (NS). Tracheal colonization was observed at a rate of 91% with the Humid-Vent Filter Light and 97% with the Clear ThermAl (NS). The rate of ventilator-associated pneumonia was similar in both groups (35%). Bacteria responsible for tracheal colonization and pneumonia were similar in both groups. Despite differences in their components, the two HMEFs that were tested achieved similar performances in terms of humidification and heating of inspired gases. Only one episode of endotracheal tube occlusion was detected, and very few patients (three in each group) had to be switched to an active heated humidifier. No difference was observed either in the rate of tracheal colonization or of ventilator-associated pneumonia. These data show that the Humid-Vent Filter Light and the Clear ThermAl HMEFs are suited for use with ICU patients.

Wakata in JPM

NASA Image and Video Library

2009-06-01

ISS020-E-005881 (1 June 2009) --- Japan Aerospace Exploration Agency (JAXA) astronaut Koichi Wakata, Expedition 20 flight engineer, conducts the current periodic humidity check on the Cell Biology Experiment Facility (CBEF) in the Saibo Rack in the Kibo laboratory of the International Space Station. Wakata opened the facility’s door for wiping up any condensation inside the micro-G & 1G section, if present, and also secured floating fan mesh with Kapton tape.

Integrated Sensor Systems for UAS

DTIC Science & Technology

2008-04-01

2. Optical particle counter 0.27 5.4 3. Pyranometer 0.17 ɘ.2 4. Temp. & relative humidity 0.05 ɘ.1 5. Data acquisition system 0.15 ɘ.2 6...payload volume showing sensor instrument installation. The insert shows the Manta exterior with the cloud droplet probe and pyranometer mounted on...Instrumentation Above- 2.7 Aethalometer cloud 14 Optical particle counter Up and down pyranometers Condensation particle counter In- 3.7

Pre- and posttreatment techniques for spacecraft water recovery

NASA Technical Reports Server (NTRS)

Putnam, David F.; Colombo, Gerald V.; Michalek, William F.

1987-01-01

The objective was to develop techniques for satisfactory pretreatment of waste water (urine and wash water) prior to recovery by distillation and satisfactory post-treatment of the recovered water and humidity condensate for purification to the high quality necessary for reuse. The effort included literature and laboratory investigations, feasibility evaluations of candidate approaches, and development of conceptual designs for a waste water pretreatment system and a recovered water post-treatment system.

Variability in morphology, hygroscopicity, and optical properties of soot aerosols during atmospheric processing

PubMed Central

Zhang, Renyi; Khalizov, Alexei F.; Pagels, Joakim; Zhang, Dan; Xue, Huaxin; McMurry, Peter H.

2008-01-01

The atmospheric effects of soot aerosols include interference with radiative transfer, visibility impairment, and alteration of cloud formation and are highly sensitive to the manner by which soot is internally mixed with other aerosol constituents. We present experimental studies to show that soot particles acquire a large mass fraction of sulfuric acid during atmospheric aging, considerably altering their properties. Soot particles exposed to subsaturated sulfuric acid vapor exhibit a marked change in morphology, characterized by a decreased mobility-based diameter but an increased fractal dimension and effective density. These particles experience large hygroscopic size and mass growth at subsaturated conditions (<90% relative humidity) and act efficiently as cloud-condensation nuclei. Coating with sulfuric acid and subsequent hygroscopic growth enhance the optical properties of soot aerosols, increasing scattering by ≈10-fold and absorption by nearly 2-fold at 80% relative humidity relative to fresh particles. In addition, condensation of sulfuric acid is shown to occur at a similar rate on ambient aerosols of various types of a given mobility size, regardless of their chemical compositions and microphysical structures. Representing an important mechanism of atmospheric aging, internal mixing of soot with sulfuric acid has profound implications on visibility, human health, and direct and indirect climate forcing. PMID:18645179

Molecular Characterization of Organosulfur Compounds in Biodiesel and Diesel Fuel Secondary Organic Aerosol

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blair, Sandra L.; MacMillan, Amanda C.; Drozd, Greg T.

Secondary organic aerosol (SOA), formed in a process of photooxidization of diesel fuel, biodiesel fuel, and 20% biodiesel fuel/80% diesel fuel mixture, are prepared under high-NOx conditions in the presence and absence of sulfur dioxide (SO2), ammonia (NH3), and relative humidity (RH). The composition of condensed-phase organic compounds in SOA is measured using several analytical techniques including aerosol mass spectrometry (AMS), high-resolution nanospray desorption electrospray ionization mass spectrometry (nano-DESI/HRMS), and ultra high resolution and mass accuracy 21T Fourier transform ion cyclotron resonance mass spectrometry (21T FT-ICR MS). Results demonstrate that sulfuric acid and condensed organosulfur species formed in photooxidation experimentsmore » with SO2 are present in the SOA particles. Fewer organosulfur species are formed in the high humidity experiments, performed at RH 90%, in comparison with experiments done under dry conditions. There is a strong overlap of organosulfur species observed in this study with previous field and chamber studies of SOA. Many mass spectrometry peaks of organosulfates (R–OS(O)2OH) in field studies previously designated as biogenic or of unknown origin might have originated from anthropogenic sources, such as photooxidation of hydrocarbons present in diesel and biodiesel fuel.« less

ISS Potable Water Quality for Expeditions 26 through 30

NASA Technical Reports Server (NTRS)

Straub, John E., II; Plumlee, Debrah K.; Schultz, John R.; McCoy, J. Torin

2012-01-01

International Space Station (ISS) Expeditions 26-30 spanned a 16-month period beginning in November of 2010 wherein the final 3 flights of the Space Shuttle program finished ISS construction and delivered supplies to support the post-shuttle era of station operations. Expedition crews relied on several sources of potable water during this period, including water recovered from urine distillate and humidity condensate by the U.S. water processor, water regenerated from humidity condensate by the Russian water recovery system, and Russian ground-supplied potable water. Potable water samples collected during Expeditions 26-30 were returned on Shuttle flights STS-133 (ULF5), STS-134 (ULF6), and STS-135 (ULF7), as well as Soyuz flights 24-27. The chemical quality of the ISS potable water supplies continued to be verified by the Johnson Space Center s Water and Food Analytical Laboratory (WAFAL) via analyses of returned water samples. This paper presents the chemical analysis results for water samples returned from Expeditions 26-30 and discusses their compliance with ISS potable water standards. The presence or absence of dimethylsilanediol (DMSD) is specifically addressed, since DMSD was identified as the primary cause of the temporary rise and fall in total organic carbon of the U.S. product water that occurred in the summer of 2010.

Removal mechanisms of dew via self-propulsion off the gecko skin.

PubMed

Watson, Gregory S; Schwarzkopf, Lin; Cribb, Bronwen W; Myhra, Sverre; Gellender, Marty; Watson, Jolanta A

2015-04-06

Condensation resulting in the formation of water films or droplets is an unavoidable process on the cuticle or skin of many organisms. This process generally occurs under humid conditions when the temperature drops below the dew point. In this study, we have investigated dew conditions on the skin of the gecko Lucasium steindachneri. When condensation occurs, we show that small dew drops, as opposed to a thin film, form on the lizard's scales. As the droplets grow in size and merge, they can undergo self-propulsion off the skin and in the process can be carried away a sufficient distance to freely engage with external forces. We show that factors such as gravity, wind and fog provide mechanisms to remove these small droplets off the gecko skin surface. The formation of small droplets and subsequent removal from the skin may aid in reducing microbial contact (e.g. bacteria, fungi) and limit conducive growth conditions under humid environments. As well as providing an inhospitable microclimate for microorganisms, the formation and removal of small droplets may also potentially aid in other areas such as reduction and cleaning of some surface contaminants consisting of single or multiple aggregates of particles. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

An ultrahigh-accuracy Miniature Dew Point Sensor based on an Integrated Photonics Platform

PubMed Central

Tao, Jifang; Luo, Yu; Wang, Li; Cai, Hong; Sun, Tao; Song, Junfeng; Liu, Hui; Gu, Yuandong

2016-01-01

The dew point is the temperature at which vapour begins to condense out of the gaseous phase. The deterministic relationship between the dew point and humidity is the basis for the industry-standard “chilled-mirror” dew point hygrometers used for highly accurate humidity measurements, which are essential for a broad range of industrial and metrological applications. However, these instruments have several limitations, such as high cost, large size and slow response. In this report, we demonstrate a compact, integrated photonic dew point sensor (DPS) that features high accuracy, a small footprint, and fast response. The fundamental component of this DPS is a partially exposed photonic micro-ring resonator, which serves two functions simultaneously: 1) sensing the condensed water droplets via evanescent fields and 2) functioning as a highly accurate, in situ temperature sensor based on the thermo-optic effect (TOE). This device virtually eliminates most of the temperature-related errors that affect conventional “chilled-mirror” hygrometers. Moreover, this DPS outperforms conventional “chilled-mirror” hygrometers with respect to size, cost and response time, paving the way for on-chip dew point detection and extension to applications for which the conventional technology is unsuitable because of size, cost, and other constraints. PMID:27417734

Printed Circuit Board Surface Finish and Effects of Chloride Contamination, Electric Field, and Humidity on Corrosion Reliability

NASA Astrophysics Data System (ADS)

Conseil-Gudla, Hélène; Jellesen, Morten S.; Ambat, Rajan

2017-02-01

Corrosion reliability is a serious issue today for electronic devices, components, and printed circuit boards (PCBs) due to factors such as miniaturization, globalized manufacturing practices which can lead to process-related residues, and global usage effects such as bias voltage and unpredictable user environments. The investigation reported in this paper focuses on understanding the synergistic effect of such parameters, namely contamination, humidity, PCB surface finish, pitch distance, and potential bias on leakage current under different humidity levels, and electrochemical migration probability under condensing conditions. Leakage currents were measured on interdigitated comb test patterns with three different types of surface finish typically used in the electronics industry, namely gold, copper, and tin. Susceptibility to electrochemical migration was studied under droplet conditions. The level of base leakage current (BLC) was similar for the different surface finishes and NaCl contamination levels up to relative humidity (RH) of 65%. A significant increase in leakage current was found for comb patterns contaminated with NaCl above 70% to 75% RH, close to the deliquescent RH of NaCl. Droplet tests on Cu comb patterns with varying pitch size showed that the initial BLC before dendrite formation increased with increasing NaCl contamination level, whereas electrochemical migration and the frequency of dendrite formation increased with bias voltage. The effect of different surface finishes on leakage current under humid conditions was not very prominent.

Orange County Outdoor School: Cabin Leader's Manual.

ERIC Educational Resources Information Center

Orange County Dept. of Education, Santa Ana, CA.

Presented in five sections, the manual furnishes cabin leaders (high school students) with background information concerning philosophy, teaching, objectives, daily schedule, and cabin leader responsibilities in the Orange County Outdoor School program. The welcome section contains the history of the Outdoor School, staff responsibilities,…

Glass formation and unusual hygroscopic growth of iodic acid solution droplets with relevance for iodine oxide particles in the coastal marine boundary layer

NASA Astrophysics Data System (ADS)

Murray, B. J.; Haddrell, A. E.; Peppe, S.; Davies, J. F.; Reid, J. P.; O'Sullivan, D.; Price, H. C.; Kumar, R.; Saunders, R. W.; Plane, J. M. C.; Umo, N. S.; Wilson, T. W.

2012-03-01

Iodine oxide particles are known to nucleate in the marine boundary layer where gas phase molecular iodine and organoiodine species are produced by macroalgae. There has been some debate over the chemical identity of these particles. Hygroscopic measurements have been used to infer that they are composed of insoluble I2O4, while elemental analysis of laboratory generated particles suggests soluble I2O5 or its hydrated form iodic acid, HIO3 (I2O5 · H2O). In this paper we explore the response of super-micron sized aqueous iodic acid solution droplets to varying humidity using both Raman microscopy and single particle electrodynamic traps. These measurements reveal that the propensity of an iodic acid solution droplet to crystallise is negligible on drying to ~0% relative humidity (RH). On applying mechanical pressure to these droplets they shatter in a manner consistent with an ultra-viscous liquid or a brittle glass, but subsequent water uptake between 10 and 20% RH causes their viscosity to reduce sufficiently that the cracked droplets flow and merge. The persistence of iodic acid solution in an amorphous state, rather than a crystalline state, suggests they will more readily accommodate other condensable material and are therefore more likely to grow to sizes where they may serve as cloud condensation nuclei. On increasing the humidity to ~90% the mass of the droplets only increases by ~20% with a corresponding increase in radius of only ~6 %, which is remarkably small for a highly soluble material. We suggest that the small growth factor of aqueous iodic acid solution droplets is consistent with the small aerosol growth factors observed in field experiments.

Airline chair-rest deconditioning: induction of immobilisation thromboemboli?

PubMed

Greenleaf, John E; Rehrer, Nancy J; Mohler, Stanley R; Quach, David T; Evans, David G

2004-01-01

Air passenger miles will likely double by year 2020. The altered and restrictive environment in an airliner cabin can influence haematological homeostasis in passengers and crew. Flight-related deep venous thromboemboli (DVT) have been associated with at least 577 deaths on 42 of 120 airlines from 1977 to 1984 (25 deaths/million departures), whereas many such cases go unreported. However, there are four major factors that could influence formation of possible flight-induced DVT: sleeping accommodations (via sitting immobilisation); travellers' medical history (via tissue injury); cabin environmental factors (via lower partial pressure of oxygen and lower relative humidity); and the more encompassing chair-rest deconditioning (C-RD) syndrome. There is ample evidence that recent injury and surgery (especially in deconditioned hospitalised patients) facilitate thrombophlebitis and formation of DVT that may be exacerbated by the immobilisation of prolonged air travel. In the healthy flying population, immobilisation factors associated with prolonged (>5 hours) C-RD such as total body dehydration, hypovolaemia and increased blood viscosity, and reduced venous blood flow (pooling) in the legs may facilitate formation of DVT. However, data from at least four case-controlled epidemiological studies did not confirm a direct causative relationship between air travel and DVT, but factors such as a history of vascular thromboemboli, venous insufficiency, chronic heart failure, obesity, immobile standing position, more than three pregnancies, infectious disease, long-distance travel, muscular trauma and violent physical effort were significantly more frequent in DVT patients than in controls. Thus, there is no clear, direct evidence yet that prolonged sitting in airliner seats, or prolonged experimental chair-rest or bed-rest deconditioning treatments cause DVT in healthy people.

Airline chair-rest deconditioning: induction of immobilisation thromboemboli?

NASA Technical Reports Server (NTRS)

Greenleaf, John E.; Rehrer, Nancy J.; Mohler, Stanley R.; Quach, David T.; Evans, David G.

2004-01-01

Air passenger miles will likely double by year 2020. The altered and restrictive environment in an airliner cabin can influence haematological homeostasis in passengers and crew. Flight-related deep venous thromboemboli (DVT) have been associated with at least 577 deaths on 42 of 120 airlines from 1977 to 1984 (25 deaths/million departures), whereas many such cases go unreported. However, there are four major factors that could influence formation of possible flight-induced DVT: sleeping accommodations (via sitting immobilisation); travellers' medical history (via tissue injury); cabin environmental factors (via lower partial pressure of oxygen and lower relative humidity); and the more encompassing chair-rest deconditioning (C-RD) syndrome. There is ample evidence that recent injury and surgery (especially in deconditioned hospitalised patients) facilitate thrombophlebitis and formation of DVT that may be exacerbated by the immobilisation of prolonged air travel.In the healthy flying population, immobilisation factors associated with prolonged (>5 hours) C-RD such as total body dehydration, hypovolaemia and increased blood viscosity, and reduced venous blood flow (pooling) in the legs may facilitate formation of DVT. However, data from at least four case-controlled epidemiological studies did not confirm a direct causative relationship between air travel and DVT, but factors such as a history of vascular thromboemboli, venous insufficiency, chronic heart failure, obesity, immobile standing position, more than three pregnancies, infectious disease, long-distance travel, muscular trauma and violent physical effort were significantly more frequent in DVT patients than in controls. Thus, there is no clear, direct evidence yet that prolonged sitting in airliner seats, or prolonged experimental chair-rest or bed-rest deconditioning treatments cause DVT in healthy people.

A Design of a Novel Airborne Aerosol Spectrometer for Remote Sensing Validation

NASA Astrophysics Data System (ADS)

Adler, G. A.; Brock, C. A.; Dube, W. P.; Erdesz, F.; Gordon, T.; Law, D. C.; Manfred, K.; Mason, B. J.; McLaughlin, R. J.; Richardson, M.; Wagner, N. L.; Washenfelder, R. A.; Murphy, D. M.

2016-12-01

Aerosols and their effect on the radiative properties of clouds contribute one of the largest sources of uncertainty to the Earth's energy budget. Many current global assessments, of atmospheric aerosol radiative forcing rely heavily on remote sensing observation; therefore, in situ aircraft and ground-based measurements are essential for validation of remote sensing measurements. Cavity ringdown spectrometers (CRD) measure aerosol extinction and are commonly used to validate remote sensing observations. These instruments have been deployed on aircraft based platforms over the years thus providing the opportunity to measure these properties over large areas in various conditions. However, deployment of the CRD on an aircraft platform has drawbacks. Typically, aircraft based CRDs draw sampled aerosol into a cabin based instrument through long lengths of tubing. This limits the ability of the instrument to measure: 1) Course mode aerosols (e.g. dust) 2) Aerosols at high relative humidity (above 90%) Here we describe the design of a novel aircraft based open path CRD. The open path CRD is intended to be mounted external to the cabin and has no sample tubing for aerosol delivery, thus measuring optical properties of all aerosol at the ambient conditions. However, the design of an open path CRD for operation on a wing-mounted aircraft platform has certain design complexities. The instrument's special design features include 2 CRD channels, 2 airfoils around the open Path CRD and a configuration which could be easily aligned and rigid at the same time. This novel implementation of cavity ringdown spectroscopy will provide a better assessment of the accuracy of remote sensing satellite measurements

Performance of school bus retrofit systems: ultrafine particles and other vehicular pollutants.

PubMed

Zhang, Qunfang; Zhu, Yifang

2011-08-01

This study evaluated the performance of retrofit systems for diesel-powered school buses, a diesel oxidation catalyst (DOC) muffler and a spiracle crankcase filtration system (CFS), regarding ultrafine particles (UFPs) and other air pollutants from tailpipe emissions and inside bus cabins. Tailpipe emissions and in-cabin air pollutant levels were measured before and after retrofitting when the buses were idling and during actual pick-up/drop off routes. Retrofit systems significantly reduced tailpipe emissions with a reduction of 20-94% of total particles with both DOC and CFS installed. However, no unequivocal decrease was observed for in-cabin air pollutants after retrofitting. The AC/fan unit and the surrounding air pollutant concentrations played more important roles for determining the in-cabin air quality of school buses than did retrofit technologies. Although current retrofit systems reduce children's exposure while waiting to board at a bus station, retrofitting by itself does not protect children satisfactorily from in-cabin particle exposures. Turning on the bus engine increased in-cabin UFP levels significantly only when the wind blew from the bus' tailpipe toward its hood with its windows open. This indicated that wind direction and window position are significant factors determining how much self-released tailpipe emissions may penetrate into the bus cabin. The use of an air purifier was found to remove in-cabin particles by up to 50% which might be an alternative short-to-medium term strategy to protect children's health.

Effect of photochemical aging on the ice nucleation properties of diesel and wood burning particles

NASA Astrophysics Data System (ADS)

Chou, C.; Stetzer, O.; Tritscher, T.; Chirico, R.; Heringa, M. F.; Kanji, Z. A.; Weingartner, E.; Prévôt, A. S. H.; Baltensperger, U.; Lohmann, U.

2012-06-01

A measurement campaign (IMBALANCE) was conducted in 2009 and aimed at characterizing the physical and chemical properties of freshly emitted and photochemically aged combustion particles emitted from a log wood burner and diesel vehicles: a EURO3 Opel Astra with a diesel oxidation catalyst (DOC) but no particle filter and a EURO2 Volkswagen Transporter TDI Syncro with no emission after-treatment. Ice nucleation experiments in the deposition and condensation freezing modes were conducted with the Portable Ice Nucleation Chamber (PINC) at three nominal temperatures, -30 °C, -35 °C and -40 °C. Freshly emitted diesel particles showed ice formation only at -40 °C in the deposition mode at 137% relative humidity with respect to ice (RHi) and 92% relative humidity with respect to water (RHw), and photochemical aging did not play a role in modifying their ice nucleation behavior. Only one diesel experiment where α-pinene was added, showed an ice nucleation enhancement after the aging at -35 °C. Wood burning particles also act as ice nuclei (IN) at -40 °C in the deposition mode at the same conditions as for diesel particles and photochemical aging did also not alter the ice formation properties of the wood burning particles. Unlike diesel particles, wood burning particles form ice via condensation freezing at -35 °C with no ice nucleation observed at -30 °C for wood burning particles. Photochemical aging did not affect the ice nucleation ability of the diesel and wood burning particles at the three different temperatures investigated but a broader range of temperatures below -30 °C need to be investigated in order to draw an overall conclusion on the effect of photochemical aging on deposition/condensation ice nucleation across the entire temperature range relevant to cold clouds.

Effect of photochemical ageing on the ice nucleation properties of diesel and wood burning particles

NASA Astrophysics Data System (ADS)

Chou, C.; Kanji, Z. A.; Stetzer, O.; Tritscher, T.; Chirico, R.; Heringa, M. F.; Weingartner, E.; Prévôt, A. S. H.; Baltensperger, U.; Lohmann, U.

2013-01-01

A measurement campaign (IMBALANCE) conducted in 2009 was aimed at characterizing the physical and chemical properties of freshly emitted and photochemically aged combustion particles emitted from a log wood burner and diesel vehicles: a EURO3 Opel Astra with a diesel oxidation catalyst (DOC) but no particle filter and a EURO2 Volkswagen Transporter TDI Syncro without emission aftertreatment. Ice nucleation experiments in the deposition and condensation freezing modes were conducted with the Portable Ice Nucleation Chamber (PINC) at three nominal temperatures, -30 °C, -35 °C and -40 °C. Freshly emitted diesel particles showed ice formation only at -40 °C in the deposition mode at 137% relative humidity with respect to ice (RHi) and 92% relative humidity with respect to water (RHw), and photochemical ageing did not play a role in modifying their ice nucleation behaviour. Only one diesel experiment where α-pinene was added for the ageing process, showed an ice nucleation enhancement at -35 °C. Wood burning particles also act as ice nuclei (IN) at -40 °C in the deposition mode at the same conditions as for diesel particles and photochemical ageing also did not alter the ice formation properties of the wood burning particles. Unlike diesel particles, wood burning particles form ice via condensation freezing at -35 °C whereas no ice nucleation was observed at -30 °C. Photochemical ageing did not affect the ice nucleation ability of the diesel and wood burning particles at the three different temperatures investigated but a broader range of temperatures below -40 °C need to be investigated in order to draw an overall conclusion on the effect of photochemical ageing on deposition/condensation ice nucleation across the entire temperature range relevant to cold clouds.

2. Onroom log cabin (right), log root cellar (center), tworoom ...

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

2. On-room log cabin (right), log root cellar (center), two-room log cabin (left), and post-and-beam garage (background). View to southwest. - William & Lucina Bowe Ranch, County Road 44, 0.1 mile northeast of Big Hole River Bridge, Melrose, Silver Bow County, MT

36 CFR 13.161 - Permit application.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Section 13.161 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR... blueprint, sketch or photograph of the cabin or structure; (d) A map that shows the geographic location of... cabin or structure. All information may be provided orally except the cabin blueprint, sketch or...

78 FR 52848 - Occupational Safety and Health Standards for Aircraft Cabin Crewmembers

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-27

... [Docket No.: FAA-2012-0953] Occupational Safety and Health Standards for Aircraft Cabin Crewmembers AGENCY... regulation of some occupational safety and health conditions affecting cabin crewmembers on aircraft by the Occupational Safety and Health Administration. This policy statement will enhance occupational safety and...

[An early warning method of cucumber downy mildew in solar greenhouse based on canopy temperature and humidity modeling].

PubMed

Wang, Hui; Li, Mei-lan; Xu, Jian-ping; Chen, Mei-xiang; Li, Wen-yong; Li, Ming

2015-10-01

The greenhouse environmental parameters can be used to establish greenhouse nirco-climate model, which can combine with disease model for early warning, with aim of ecological controlling diseases to reduce pesticide usage, and protecting greenhouse ecological environment to ensure the agricultural product quality safety. Greenhouse canopy leaf temperature and air relative humidity, models were established using energy balance and moisture balance principle inside the greenhouse. The leaf temperature model considered radiation heat transfer between the greenhouse crops, wall, soil and cover, plus the heat exchange caused by indoor net radiation and crop transpiration. Furthermore, the water dynamic balance in the greenhouse including leaf transpiration, soil evaporation, cover and leaf water vapor condensation, was considered to develop a relative humidity model. The primary infection and latent period warning models for cucumber downy mildew (Pseudoperonospora cubensis) were validated using the results of the leaf temperature and relative humidity model, and then the estimated disease occurrence date of cucumber downy mildew was compared with actual disease occurrence date of field observation. Finally, the results were verified by the measured temperature and humidity data of September and October, 2014. The results showed that the root mean square deviations (RMSDs) of the measured and estimated leaf temperature were 0.016 and 0.024 °C, and the RMSDs of the measured and estimated air relative humidity were 0.15% and 0.13%, respectively. Combining the result of estimated temperature and humidity models, a cucumber disease early warning system was established to forecast the date of disease occurrence, which met with the real date. Thus, this work could provide the micro-environment data for the early warning system of cucumber diseases in solar greenhouses.

Odors and Sensations of Humidity and Dryness in Relation to Sick Building Syndrome and Home Environment in Chongqing, China

PubMed Central

Wang, Juan; Li, Baizhan; Yang, Qin; Yu, Wei; Wang, Han; Norback, Dan; Sundell, Jan

2013-01-01

The prevalence of perceptions of odors and sensations of air humidity and sick building syndrome symptoms in domestic environments were studied using responses to a questionnaire on the home environment. Parents of 4530 1–8 year old children from randomly selected kindergartens in Chongqing, China participated. Stuffy odor, unpleasant odor, pungent odor, mold odor, tobacco smoke odor, humid air and dry air in the last three month (weekly or sometimes) was reported by 31.4%, 26.5%, 16.1%, 10.6%, 33.0%, 32.1% and 37.2% of the parents, respectively. The prevalence of parents’ SBS symptoms (weekly or sometimes) were: 78.7% for general symptoms, 74.3% for mucosal symptoms and 47.5% for skin symptoms. Multi-nominal regression analyses for associations between odors/sensations of air humidity and SBS symptoms showed that the odds ratio for “weekly” SBS symptoms were consistently higher than for “sometimes” SBS symptoms. Living near a main road or highway, redecoration, and new furniture were risk factors for perceptions of odors and sensations of humid air and dry air. Dampness related problems (mold spots, damp stains, water damage and condensation) were all risk factors for perceptions of odors and sensations of humid air and dry air, as was the presence of cockroaches, rats, and mosquitoes/flies, use of mosquito-repellent incense and incense. Protective factors included cleaning the child’s bedroom every day and frequently exposing bedding to sunshine. In conclusion, adults’ perceptions of odors and sensations of humid air and dry air are related to factors of the home environment and SBS symptoms are related to odor perceptions. PMID:23991107

An Experimental Work On The Electrical Conductivity Of PEG Under Changing Relative Humidity

NASA Astrophysics Data System (ADS)

Erdamar, O.; Skarlatos, Y.; Aktas, G.; Inci, M. N.

2007-04-01

Polyethylene glycol (PEG) thin films are investigated experimentally. Dc measurements are done under changing relative humidity (rh) to study the change in the electrical conductivity. Upto 70 % rh, electronic conduction takes place with the increase in the current as a result of the absorbed water. Around 70 % rh, the polymer melts from the semicrystalline form, the water vapor condenses and conduction begins to take an ionic nature. At that point, the current shows a sudden increase. After 75 % rh, the conductivity shows irregularities with respect to the increase in rh. There is a hysterisis between the absorption and desorption of water as the film can not get its pre-absorption form, which can be maintained after drying the sample, in the time interval of desorption.

Site of water vapor absorption in the desert cockroach, Arenivaga investigata.

PubMed Central

O'Donnell, M J

1977-01-01

The desert cockroach, Arenivaga investigata, can gain weight by absorption of water-vapor from unsaturated atmospheres above 82.5% relative humidity. Blocking the anus or the dorsal surface with wax does not prevent water vapor uptake, but interference with movements of the mouthparts or blocking the mouth with wax-prevents such uptake. Weight gains are associated with the protrusion from the mouth of two bladder-like extensions of the hypopharynx. During absorption these structures are warmer than the surrounding mouthparts, their surface temperature increasing with relative humidity. This suggests that the surfaces of the bladder-like structures function at least as sites for condensation of water vapor, but the precise location of its transfer into the hemolymph has not yet been identified. Images PMID:266217

33 CFR 110.71a - Cabin Creek, Grasonville, Md.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Cabin Creek, Grasonville, Md. 110.71a Section 110.71a Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY ANCHORAGES ANCHORAGE REGULATIONS Special Anchorage Areas § 110.71a Cabin Creek, Grasonville, Md. The waters...

33 CFR 110.71a - Cabin Creek, Grasonville, Md.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Cabin Creek, Grasonville, Md. 110.71a Section 110.71a Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY ANCHORAGES ANCHORAGE REGULATIONS Special Anchorage Areas § 110.71a Cabin Creek, Grasonville, Md. The waters...

33 CFR 110.71a - Cabin Creek, Grasonville, Md.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Cabin Creek, Grasonville, Md. 110.71a Section 110.71a Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY ANCHORAGES ANCHORAGE REGULATIONS Special Anchorage Areas § 110.71a Cabin Creek, Grasonville, Md. The waters...

33 CFR 110.71a - Cabin Creek, Grasonville, Md.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Cabin Creek, Grasonville, Md. 110.71a Section 110.71a Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY ANCHORAGES ANCHORAGE REGULATIONS Special Anchorage Areas § 110.71a Cabin Creek, Grasonville, Md. The waters...

33 CFR 110.71a - Cabin Creek, Grasonville, Md.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Cabin Creek, Grasonville, Md. 110.71a Section 110.71a Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY ANCHORAGES ANCHORAGE REGULATIONS Special Anchorage Areas § 110.71a Cabin Creek, Grasonville, Md. The waters...

36 CFR 13.161 - Permit application.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Section 13.161 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Cabins Cabin Use for Subsistence Purposes § 13.161 Permit application... blueprint, sketch or photograph of the cabin or structure; (d) A map that shows the geographic location of...

36 CFR 13.161 - Permit application.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Section 13.161 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Cabins Cabin Use for Subsistence Purposes § 13.161 Permit application... blueprint, sketch or photograph of the cabin or structure; (d) A map that shows the geographic location of...

78 FR 64417 - Airworthiness Directives; Twin Commander Aircraft LLC Airplanes; Initial Regulatory Flexibility...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-10-29

... window channels, aft cabin pressure web, external wing to fuselage fillets, and fasteners; repair or..., the vertical channels, the upper picture window channels, aft cabin pressure web, external wing to... lower wing main spar, the vertical channels, the upper picture window channels, aft cabin pressure web...

77 FR 75600 - Policy Statement on Occupational Safety and Health Standards for Aircraft Cabin Crewmembers...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-12-21

... [Docket No. FAA-2012-0953] Policy Statement on Occupational Safety and Health Standards for Aircraft Cabin... announced a proposed policy statement regarding the regulation of some occupational safety and health conditions affecting cabin crewmembers on aircraft by the Occupational Safety and Health Administration. The...

Putting Safety First in the Sky

NASA Technical Reports Server (NTRS)

2003-01-01

As a result of technology developed at NASA s Kennedy Space Center, pilots now have a hand-held personal safety device to warn them of potentially dangerous or deteriorating cabin pressure altitude conditions before hypoxia becomes a threat. The Personal Cabin Pressure Altitude Monitor and Warning System monitors cabin pressure to determine when supplemental oxygen should be used according to Federal Aviation Regulations. The device benefits both pressurized and nonpressurized aircraft operations - warning pressurized aircraft when the required safe cabin pressure altitude is compromised, and reminding nonpressurized aircraft when supplemental oxygen is needed.

The Fate of Trace Contaminants in a Crewed Spacecraft Cabin Environment

NASA Technical Reports Server (NTRS)

Perry, Jay L.; Kayatin, Matthew J.

2016-01-01

Trace chemical contaminants produced via equipment offgassing, human metabolic sources, and vehicle operations are removed from the cabin atmosphere by active contamination control equipment and incidental removal by other air quality control equipment. The fate of representative trace contaminants commonly observed in spacecraft cabin atmospheres is explored. Removal mechanisms are described and predictive mass balance techniques are reviewed. Results from the predictive techniques are compared to cabin air quality analysis results. Considerations are discussed for an integrated trace contaminant control architecture suitable for long duration crewed space exploration missions.

First report of Legionella pneumophila in car cabin air filters. Are these a potential exposure pathway for professional drivers?

PubMed

Alexandropoulou, Ioanna G; Konstantinidis, Theocharis G; Parasidis, Theodoros A; Nikolaidis, Christos; Panopoulou, Maria; Constantinidis, Theodoros C

2013-12-01

Recent findings have identified professional drivers as being at an increased risk of Legionnaires' disease. Our hypothesis was that used car cabin air filters represent a reservoir of Legionella bacteria, and thus a potential pathway for contamination. We analysed used cabin air filters from various types of car. The filters were analysed by culture and by molecular methods. Our findings indicated that almost a third of air filters were colonized with Legionella pneumophila. Here, we present the first finding of Legionella spp. in used car cabin air filters. Further investigations are needed in order to confirm this exposure pathway. The presence of Legionella bacteria in used cabin air filters may have been an unknown source of infection until now.

Passenger well-being in airplanes.

PubMed

Hinninghofen, H; Enck, P

2006-10-30

Passenger well-being is influenced by cabin environmental conditions which interact with individual passenger characteristics like age and health conditions. Cabin environment is composed of different aspects, some of which have a direct influence on gastrointestinal functions and may directly generate nausea, such as cabin pressure, oxygen saturation, and motion or vibration. For example, it has been shown that available cabin pressure during normal flight altitude can significantly inhibit gastric emptying and induce dyspepsia-like symptoms when associated with a fibre-rich meal. Other aspects of the cabin environment such as space and variability of seating, air quality, and noise, also have been shown to modulate (reduce or increase) discomfort and nausea during flights. Individual passenger characteristics and health status also have been demonstrated to increase vulnerability to adverse health outcomes and discomfort.

Crane cabins' interior space multivariate anthropometric modeling.

PubMed

Essdai, Ahmed; Spasojević Brkić, Vesna K; Golubović, Tamara; Brkić, Aleksandar; Popović, Vladimir

2018-01-01

Previous research has shown that today's crane cabins fail to meet the needs of a large proportion of operators. Performance and financial losses and effects on safety should not be overlooked as well. The first aim of this survey is to model the crane cabin interior space using up-to-date crane operator anthropometric data and to compare the multivariate and univariate method anthropometric models. The second aim of the paper is to define the crane cabin interior space dimensions that enable anthropometric convenience. To facilitate the cabin design, the anthropometric dimensions of 64 crane operators in the first sample and 19 more in the second sample were collected in Serbia. The multivariate anthropometric models, spanning 95% of the population on the basis of a set of 8 anthropometric dimensions, have been developed. The percentile method was also used on the same set of data. The dimensions of the interior space, necessary for the accommodation of the crane operator, are 1174×1080×1865 mm. The percentiles results for the 5th and 95th model are within the obtained dimensions. The results of this study may prove useful to crane cabin designers in eliminating anthropometric inconsistencies and improving the health of operators, but can also aid in improving the safety, performance and financial results of the companies where crane cabins operate.

Symptom-based categorization of in-flight passenger medical incidents.

PubMed

Mahony, Paul H; Myers, Julia A; Larsen, Peter D; Powell, David M C; Griffiths, Robin F

2011-12-01

The majority of in-flight passenger medical events are managed by cabin crew. Our study aimed to evaluate the reliability of cabin crew reports of in-flight medical events and to develop a symptom-based categorization system. All cabin crew in-flight passenger medical incident reports for an airline over a 9-yr period were examined retrospectively. Validation of incident descriptions were undertaken on a sample of 162 cabin crew reports where medically trained persons' reports were available for comparison using a three Round Delphi technique and testing concordance using Cohen's Kappa. A hierarchical symptom-based categorization system was designed and validated. The rate was 159 incidents per 106 passengers carried, or 70.4/113.3 incidents per 106 revenue passenger kilometres/miles, respectively. Concordance between cabin crew and medical reports was 96%, with a high validity rating (mean 4.6 on a 1-5 scale) and high Cohen's Kappa (0.94). The most common in-flight medical events were transient loss of consciousness (41%), nausea/vomiting/diarrhea (19.5%), and breathing difficulty (16%). Cabin crew records provide reliable data regarding in-flight passenger medical incidents, complementary to diagnosis-based systems, and allow the use of currently underutilized data. The categorization system provides a means for tracking passenger medical incidents internationally and an evidence base for cabin crew first aid training.

Operational Philosophy Concerning Manned Spacecraft Cabin Leaks

NASA Technical Reports Server (NTRS)

DeSimpelaere, Edward

2011-01-01

The last thirty years have seen the Space Shuttle as the prime United States spacecraft for manned spaceflight missions. Many lessons have been learned about spacecraft design and operation throughout these years. Over the next few decades, a large increase of manned spaceflight in the commercial sector is expected. This will result in the exposure of commercial crews and passengers to many of the same risks crews of the Space Shuttle have encountered. One of the more dire situations that can be encountered is the loss of pressure in the habitable volume of the spacecraft during on orbit operations. This is referred to as a cabin leak. This paper seeks to establish a general cabin leak response philosophy with the intent of educating future spacecraft designers and operators. After establishing a relative definition for a cabin leak, the paper covers general descriptions of detection equipment, detection methods, and general operational methods for management of a cabin leak. Subsequently, all these items are addressed from the perspective of the Space Shuttle Program, as this will be of the most value to future spacecraft due to similar operating profiles. Emphasis here is placed upon why and how these methods and philosophies have evolved to meet the Space Shuttle s needs. This includes the core ideas of: considerations of maintaining higher cabin pressures vs. lower cabin pressures, the pros and cons of a system designed to feed the leak with gas from pressurized tanks vs. using pressure suits to protect against lower cabin pressures, timeline and consumables constraints, re-entry considerations with leaks of unknown origin, and the impact the International Space Station (ISS) has had to the standard Space Shuttle cabin leak response philosophy. This last item in itself includes: procedural management differences, hardware considerations, additional capabilities due to the presence of the ISS and its resource, and ISS docking/undocking considerations with a cabin leak occurring. The paper also offers a look at how different equipment configurations on future spacecraft impact the previously defined cabin leak operational philosophy and includes additional operational methods and considerations that result due to various configurations. The intent is to showcase these various considerations and highlight the variability they allow. The paper concludes with a selection of the author s personal observations from a spacecraft operator's point of view and recommendations with the goal of improving the design and operations of future spacecraft.

Investigation of DMSD Trend in the ISS Water Processor Assembly

NASA Technical Reports Server (NTRS)

Carter, Layne; Bowman, Elizabeth; Wilson, Mark; Gentry, Greg; Rector, Tony

2013-01-01

The ISS Water Recovery System (WRS) is responsible for providing potable water to the crew, to the Oxygen Generation System (OGS) for oxygen production via electrolysis, to the Waste & Hygiene Compartment (WHC) for flush water, and for experiments on ISS. The WRS includes the Water Processor Assembly (WPA) and the Urine Processor Assembly (UPA). The WPA processes condensate from the cabin air and distillate produced by the UPA. In 2010, an increasing trend in the Total Organic Carbon (TOC) in the potable water was ultimately identified as dimethylsilanediol (DMSD). The increasing trend was ultimately reversed after replacing the WPA's two multifiltration beds. However, the reason for the TOC trend and the subsequent recovery was not understood. A subsequent trend occurred in 2012. This paper summarizes the current understanding of the fate of DMSD in the WPA, how the increasing TOC trend occurred, and the plan for modifying the WPA to prevent recurrence.

Payload/orbiter contamination control requirement study

NASA Technical Reports Server (NTRS)

Bareiss, L. E.; Ress, E. B.

1975-01-01

The results of a contamination impact analysis upon the spacelab carrier and the spacelab carrier upon some of its potential payloads are presented. These results are based upon contamination computer modeling techniques developed to predict the induced environment for spacelab and to provide the basis for evaluation of the predicted environment against the current on orbit contamination control criteria as specified for payloads. Those spacelab carrier contamination sources evaluated against the stated contamination control criteria were outgassing/offgassing of the major nonmetallic thermal control coating of the spacelab carriers, spacelab core and experiment module and tunnel cabin atmosphere leakage, avionics bay vent, spacelab condensate vent, random particulate sloughing, and the return flux of the molecular content of these sources from the gas-gas interactions with the ambient orbital environment. It is indicated that the spacelab carrier can meet the intent of the contamination control criteria through incorporating known contamination control practices.

Dynamics of atmospheres with a non-dilute condensible component

PubMed Central

Ding, Feng

2016-01-01

The diversity of characteristics for the host of recently discovered exoplanets opens up a great deal of fertile new territory for geophysical fluid dynamics, particularly when the fluid flow is coupled to novel thermodynamics, radiative transfer or chemistry. In this paper, we survey one of these new areas—the climate dynamics of atmospheres with a non-dilute condensible component, defined as the situation in which a condensible component of the atmosphere makes up a substantial fraction of the atmospheric mass within some layer. Non-dilute dynamics can occur for a wide range of condensibles, generically applying near both the inner and the outer edges of the conventional habitable zone and in connection with runaway greenhouse phenomena. It also applies in a wide variety of other planetary circumstances. We first present a number of analytical results developing some key features of non-dilute atmospheres, and then show how some of these features are manifest in simulations with a general circulation model adapted to handle non-dilute atmospheres. We find that non-dilute atmospheres have weak horizontal temperature gradients even for rapidly rotating planets, and that their circulations are largely barotropic. The relative humidity of the condensible component tends towards 100% as the atmosphere becomes more non-dilute, which has important implications for runaway greenhouse thresholds. Non-dilute atmospheres exhibit a number of interesting organized convection features, for which there is not yet any adequate theoretical understanding. PMID:27436980

Dynamics of atmospheres with a non-dilute condensible component.

PubMed

Pierrehumbert, Raymond T; Ding, Feng

2016-06-01

The diversity of characteristics for the host of recently discovered exoplanets opens up a great deal of fertile new territory for geophysical fluid dynamics, particularly when the fluid flow is coupled to novel thermodynamics, radiative transfer or chemistry. In this paper, we survey one of these new areas-the climate dynamics of atmospheres with a non-dilute condensible component, defined as the situation in which a condensible component of the atmosphere makes up a substantial fraction of the atmospheric mass within some layer. Non-dilute dynamics can occur for a wide range of condensibles, generically applying near both the inner and the outer edges of the conventional habitable zone and in connection with runaway greenhouse phenomena. It also applies in a wide variety of other planetary circumstances. We first present a number of analytical results developing some key features of non-dilute atmospheres, and then show how some of these features are manifest in simulations with a general circulation model adapted to handle non-dilute atmospheres. We find that non-dilute atmospheres have weak horizontal temperature gradients even for rapidly rotating planets, and that their circulations are largely barotropic. The relative humidity of the condensible component tends towards 100% as the atmosphere becomes more non-dilute, which has important implications for runaway greenhouse thresholds. Non-dilute atmospheres exhibit a number of interesting organized convection features, for which there is not yet any adequate theoretical understanding.

Effect of ambient temperature and relative humidity on interfacial temperature during early stages of drop evaporation.

PubMed

Fukatani, Yuki; Orejon, Daniel; Kita, Yutaku; Takata, Yasuyuki; Kim, Jungho; Sefiane, Khellil

2016-04-01

Understanding drop evaporation mechanisms is important for many industrial, biological, and other applications. Drops of organic solvents undergoing evaporation have been found to display distinct thermal patterns, which in turn depend on the physical properties of the liquid, the substrate, and ambient conditions. These patterns have been reported previously to be bulk patterns from the solid-liquid to the liquid-gas drop interface. In the present work the effect of ambient temperature and humidity during the first stage of evaporation, i.e., pinned contact line, is studied paying special attention to the thermal information retrieved at the liquid-gas interface through IR thermography. This is coupled with drop profile monitoring to experimentally investigate the effect of ambient temperature and relative humidity on the drop interfacial thermal patterns and the evaporation rate. Results indicate that self-generated thermal patterns are enhanced by an increase in ambient temperature and/or a decrease in humidity. The more active thermal patterns observed at high ambient temperatures are explained in light of a greater temperature difference generated between the apex and the edge of the drop due to greater evaporative cooling. On the other hand, the presence of water humidity in the atmosphere is found to decrease the temperature difference along the drop interface due to the heat of adsorption, absorption and/or that of condensation of water onto the ethanol drops. The control, i.e., enhancement or suppression, of these thermal patterns at the drop interface by means of ambient temperature and relative humidity is quantified and reported.

Characterisation of neutron-sensitive bubble detectors for application in the measurement of jet aircrew exposure to natural background radiation.

PubMed

Tume, P; Lewis, B J; Bennett, L G; Cousins, T

1998-01-01

A survey of the natural background dose equivalent received by Canadian Forces aircrew was conducted using neutron-sensitive bubble detectors (BDs) as the primary detection tool. Since this study was a new application for these detectors, the BD response to neutron dose equivalent (RD) was extended from thermal to 500 MeV in neutron energy. Based upon the extended RD, it was shown that the manufacturer's calibration can be scaled by 1.5 +/- 0.5 to give a BD sensitivity that takes into account recently recommended fluence-to-neutron dose equivalent conversion functions and the cosmogenic neutron spectrum encountered at jet altitudes. An investigation of the effects of systematic bias caused by the cabin environment (i.e., temperature, pressure and relative humidity) on the in-flight measurements was also conducted. Both simulated and actual aircraft climate tests indicated that the detectors are insensitive to the pressure and relative humidity variations encountered during routine jet aircraft operations. Long term conditioning tests also confirmed that the BD-PND model of detector is sensitive to variations in temperature to within +/- 20%. As part of the testing process, the in-flight measurements also demonstrated that the neutron dose equivalent is distributed uniformly throughout a Boeing 707 jet aircraft, indicating that both pilots and flight attendants are exposed to the same neutron field intensity to within experimental uncertainty.

Widespread morning drizzle on Titan.

PubMed

Adámkovics, Máté; Wong, Michael H; Laver, Conor; de Pater, Imke

2007-11-09

Precipitation is expected in Titan's atmosphere, yet it has not been directly observed, and the geographical regions where rain occurs are unknown. Here we present near-infrared spectra from the Very Large Telescope and W. M. Keck Observatories that reveal an enhancement of opacity in Titan's troposphere on the morning side of the leading hemisphere. Retrieved extinction profiles are consistent with condensed methane in clouds at an altitude near 30 kilometers and concomitant methane drizzle below. The moisture encompasses the equatorial region over Titan's brightest continent, Xanadu. Diurnal temperature gradients that cause variations in methane relative humidity, winds, and topography may each be a contributing factor to the condensation mechanism. The clouds and precipitation are optically thin at 2.0 micrometers, and models of "subvisible" clouds suggest that the droplets are 0.1 millimeter or larger.

Factors affecting ozone removal rates in a simulated aircraft cabin environment

NASA Astrophysics Data System (ADS)

Tamás, Gyöngyi; Weschler, Charles J.; Bakó-Biró, Zsolt; Wyon, David P.; Strøm-Tejsen, Peter

Ozone concentrations were measured concurrently inside a simulated aircraft cabin and in the airstream providing ventilation air to the cabin. Ozone decay rates were also measured after cessation of ozone injection into the supply airstream. By systematically varying the presence or absence of people, soiled T-shirts, aircraft seats and a used HEPA filter, we have been able in the course of 24 experiments to isolate the contributions of these and other factors to the removal of ozone from the cabin air. In the case of this simulated aircraft, people were responsible for almost 60% of the ozone removal occurring within the cabin and recirculation system; respiration can only have been responsible for about 4% of this removal. The aircraft seats removed about 25% of the ozone; the loaded HEPA filter, 7%; and the other surfaces, 10%. A T-shirt that had been slept in overnight removed roughly 70% as much ozone as a person, indicating the importance of skin oils in ozone removal. The presence of the used HEPA filter in the recirculated airstream reduced the perceived air quality. Over a 5-h period, the overall ozone removal rate by cabin surfaces decreased at ˜3% h -1. With people present, the measured ratio of ozone's concentration in the cabin versus that outside the cabin was 0.15-0.21, smaller than levels reported in the literature. The results reinforce the conclusion that the optimal way to reduce people's exposure to both ozone and ozone oxidation products is to efficiently remove ozone from the air supply system of an aircraft.

Comparison of inflight first aid performed by cabin crew members and medical volunteers.

PubMed

Kim, Jung Ha; Choi-Kwon, Smi; Park, Young Hwan

2017-03-01

Since the number of air travellers, including the elderly and passengers with an underlying disease, is increasing every year, the number of inflight emergency patients is expected to increase as well. We attempted to identify the incidence and types of reported inflight medical incidents and analyse the first aid performed by cabin crew members or medical volunteers in flights by an Asian airline. We also investigated the cases of inflight deaths and aircraft diversions. We reviewed the cabin reports and medical records submitted by cabin crew members and inflight medical volunteers from 2009 to 2013. We found that inflight medical incidents increased annually, with a total of 2818 cases reported. Fifteen cases of inflight deaths and 15 cases of aircraft diversions during this period were also reported. First aid was performed by the cabin crew alone in 52% of the cases and by medical volunteers in 47.8% of the cases. The most commonly reported causes for first aid performed by the cabin crew and medical volunteers were burns and syncope, respectively. : Since burns were one of the common reasons that first aid was provided by the cabin crew, it may be necessary to include first aid treatments for burns in the annual re-qualification training programme. Furthermore, the assessment of unconsciousness and potentially critical respiratory symptoms is very important for cabin crew members because those conditions can lead to inflight deaths and aircraft diversion. © International Society of Travel Medicine, 2017. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com

76 FR 5505 - Airworthiness Directives; The Boeing Company Model 777-200 Series Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2011-02-01

... management units (ZMU) OPS, and the cabin system management unit (CSMU) OPS; installing OPS for the CSCP... require installing a new CSCP; installing a new cabin management system (CMS) CDB; and installing new OPS...), the zone management unit (ZMU) OPS, and the cabin system management unit (CSMU) OPS. Installing CSCP...

Cabin Pressure Monitors Notify Pilots to Save Lives

NASA Technical Reports Server (NTRS)

2015-01-01

In 2013, San Diego-based Aviation Technology Inc. obtained an exclusive license for the technology behind the cabin pressure monitor invented at Kennedy Space Center and built its own version of the product. The Alt Alert is designed to save lives by alerting aircraft pilots and crews when cabin pressure becomes dangerously low.

Protective Clothing

DTIC Science & Technology

1975-01-01

WASHINGTON 0 C AEROSPACE TECHNOLOGY DIV HIGH -ALTITUDE PRESSURESUITS AND HERMETICALLY SEALED CABINS FOR STRATOSPHERIC FLIGHTS* (U) DESCRIPTIVE NOTE...TRANS. FROM VESTNIK VOZDUSNNOGO FLOTA, NO. So PP. 48൹, |938. DESCRIPTORS: (*PRESSURE SUITS. USSR)o PRESSURIZED CABINS. HERMETIC SEALS, HIGH ALTITUDE...STRATOSPHERE, BREATHING APPARATUS, OXYGEN EQUIPMENT, REVIEWS, DESIG(U) HIGH -ALTITUDE PRESSURE SUITS AND HERMETICALLY SEALED CABINS FOR STRATOSPHERIC

36 CFR 13.1306 - Public use cabins.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Public use cabins. 13.1306 Section 13.1306 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR... Superintendent. (c) Lighting or maintaining a fire within 500 feet of the North Arm or Holgate public use cabins...

Validation for CFD Prediction of Mass Transport in an Aircraft Passenger Cabin

DTIC Science & Technology

2006-11-01

35 VHP temporal evolution CFD prediction...Graphic illustrating introduction of VHP stream into AERF through nominal 4-in diameter duct. a) (above) global view facing cabin sidewall, b) (lower...distribution within the AERF ventilation system flow field. This was accomplished by introducing vaporized hydrogen peroxide ( VHP ) into a cabin

14 CFR 121.333 - Supplemental oxygen for emergency descent and for first aid; turbine engine powered airplanes...

Code of Federal Regulations, 2011 CFR

2011-01-01

... and for first aid; turbine engine powered airplanes with pressurized cabins. 121.333 Section 121.333... for emergency descent and for first aid; turbine engine powered airplanes with pressurized cabins. (a) General. When operating a turbine engine powered airplane with a pressurized cabin, the certificate holder...

14 CFR 121.333 - Supplemental oxygen for emergency descent and for first aid; turbine engine powered airplanes...

Code of Federal Regulations, 2010 CFR

2010-01-01

... and for first aid; turbine engine powered airplanes with pressurized cabins. 121.333 Section 121.333... for emergency descent and for first aid; turbine engine powered airplanes with pressurized cabins. (a) General. When operating a turbine engine powered airplane with a pressurized cabin, the certificate holder...

36 CFR 13.1306 - Public use cabins.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 36 Parks, Forests, and Public Property 1 2011-07-01 2011-07-01 false Public use cabins. 13.1306 Section 13.1306 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR... Superintendent. (c) Lighting or maintaining a fire within 500 feet of the North Arm or Holgate public use cabins...

Discover Presidential Log Cabins. Teacher's Discussion Guide.

ERIC Educational Resources Information Center

National Park Service (Dept. of Interior), Washington, DC.

Discover Presidential Log Cabins is a set of materials designed to help educate 6-8 grade students about the significance of three log cabin sites occupied by George Washington, Ulysses Grant, Abraham Lincoln, and Theodore Roosevelt. This teacher's discussion guide is intended for use as part of a larger, comprehensive social studies program, and…

Numerical Study of Ammonia Leak and Dispersion in the International Space Station

NASA Technical Reports Server (NTRS)

Son, Chang H.

2012-01-01

Release of ammonia into the International Space Station (ISS) cabin atmosphere can occur if the water/ammonia barrier breach of the active thermal control system (ATCS) interface heat exchanger (IFHX) happens. After IFHX breach liquid ammonia is introduced into the water-filled internal thermal control system (ITCS) and then to the cabin environment through a ruptured gas trap. Once the liquid water/ammonia mixture exits ITCS, it instantly vaporizes and mixes with the U.S. Laboratory cabin air that results in rapid deterioration of the cabin conditions. The goal of the study is to assess ammonia propagation in the Station after IFHX breach to plan the operation procedure. A Computational Fluid Dynamics (CFD) model for accurate prediction of airflow and ammonia transport within each of the modules in the ISS cabin was developed. CFD data on ammonia content in the cabin aisle way of the ISS and, in particular, in the Russian On- Orbit Segment during the period of 15 minutes after gas trap rupture are presented for four scenarios of rupture response. Localized effects of ammonia dispersion and risk mitigation are discussed.

A modified MBR system with post advanced purification for domestic water supply system in 180-day CELSS: Construction, pollutant removal and water allocation.

PubMed

Li, Ting; Zhang, Liangchang; Ai, Weidang; Dong, Wenyi; Yu, Qingni

2018-05-22

Water supply was vital to people's life, especially inside Controlled Ecological Life Support System (CELSS) for long-term space exploration. A platform of 4-person-180-day integrated experiment inside a CELSS including 6 cabins called 'SPACEnter' was established in Shenzhen, China. Based on this platform, a Membrane Bio-Reactor (MBR) system configuring post advanced purification, including I-MBR, II-MBR, nanofiltration (NF), reverse osmosis (RO), ion-exchange (IE), polyiodide disinfection (PI) and mineralization (MC) stages, used as a Domestic Water Supply System (DWSS) to guarantee crew's daily life was constructed. The performance of DWSS to treat the real plant cabin's condensate water was examined during continuously 180-day experiment. The long-term operation results showed that, though the influent pollutant load changed as the experiment processing, the system exhibited stable performance on pollutants removal with average effluent TOC＜0.5 mg/L, NH 4 + -N＜0.02 mg/L, NO 3 - -N＜0.25 mg/L, NO 2 - -N＜0.001 mg/L, and displayed good capacity for controlling the trace metal ions and microorganism. The effluent through such modified MBR system was sufficiently allocated as hygiene water and potable water, and the average value was 39.69 and 10.93 L/d, respectively. The consumption of the modified MBR process was within the designed allowable scope. The outcomes of this study will be helpful for facilitating future applications of MBR as bio-based water supply technology in the CELSS. Copyright © 2018 Elsevier Ltd. All rights reserved.

Rescue Shuttle Flight Re-Entry: Controlling Astronaut Thermal Exposure

NASA Technical Reports Server (NTRS)

Gillis, David B.; Hamilton, Douglas; Ilcus, Stana; Stepaniak, Phil; Polk, J. D.; Son, Chang; Bue, Grant

2008-01-01

A rescue mission for the STS-125 Hubble Telescope Repair Mission requires reentry from space with 11 crew members aboard, exceeding past cabin thermal load experience and risking crew thermal stress potentially causing cognitive performance and physiological decrements. The space shuttle crew cabin air revitalization system (ARS) was designed to support a nominal crew complement of 4 to 7 crew and 10 persons in emergencies, all in a shirt-sleeve environment. Subsequent to the addition of full pressure suits with individual cooling units, the ARS cannot maintain a stable temperature in the crew cabin during reentry thermal loads. Bulk cabin thermal models, used for rescue mission planning and analysis of crew cabin air, were unable to accurately represent crew workstation values of air flow, carbon dioxide, and heat content for the middeck. Crew temperature models suggested significantly elevated core temperatures. Planning for an STS-400 potential rescue of seven stranded crew utilized computational fluid dynamics (CFD) models to demonstrate inhomogeneous cabin thermal properties and improve analysis compared to bulk models. In the absence of monitoring of crew temperature, heart rate, metabolic rate and incomplete engineering data on the performance of the integrated cooling garment/cooling unit (ICG/CU) at cabin temperatures above 75 degrees F, related systems & models were reevaluated and tests conducted with humans in the loop. Changes to the cabin ventilation, ICU placement, crew reentry suit-donning procedures, Orbiter Program wave-off policy and post-landing power down and crew extraction were adopted. A second CFD and core temperature model incorporated the proposed changes and confirmed satisfactory cabin temperature, improved air distribution, and estimated core temperatures within safe limits. CONCLUSIONS: These changes in equipment, in-flight and post-landing procedures, and policy were implemented for the STS-400 rescue shuttle & will be implemented in any future rescue flights from the International Space Station of stranded shuttle crews.

Effect of humidity and water intercalation on the tribological behavior of graphene and graphene oxide.

PubMed

Arif, Taib; Colas, Guillaume; Filleter, Tobin

2018-06-12

In this work, the effect of humidity and water intercalation on the friction and wear behavior of few-layers of graphene and graphene oxide (GO) was studied using friction force microscopy. Thickness measurements demonstrated significant water intercalation within GO affecting its surface topography (roughness and protrusions), whereas negligible water intercalation of graphene was observed. It was found that water intercalation in GO contributed to wearing of layers at a relative humidity as low as ~30%. The influence of surface wettability and water adsorption was also studied by comparing the sliding behavior of SiO2/GO, SiO2/Graphene, and SiO2/SiO2 interfaces. Friction for the SiO2/GO interface increased with relative humidity due to water intercalation and condensation of water. In contrast, it was observed that adsorption of water molecules lubricated the SiO2/SiO2 interface due to easy shearing of water on the hydrophobic surface, particularly once the adsorbed water layers had transitioned from "ice-like water" to "liquid-like water" structures. Lastly, an opposite friction trend was observed for the graphene/SiO2 interface with water molecules failing to lubricate the interface as compared to the dry graphene/SiO2 contact.

Experimental investigation of personal air supply nozzle use in aircraft cabins.

PubMed

Fang, Zhaosong; Liu, Hong; Li, Baizhan; Baldwin, Andrew; Wang, Jian; Xia, Kechao

2015-03-01

To study air passengers' use of individual air supply nozzles in aircraft cabins, we constructed an experimental chamber which replicated the interior of a modern passenger aircraft. A series of experiments were conducted at different levels of cabin occupancy. Survey data were collected focused on the reasons for opening the nozzle, adjusting the level of air flow, and changing the direction of the air flow. The results showed that human thermal and draft sensations change over time in an aircraft cabin. The thermal sensation response was highest when the volunteers first entered the cabin and decreased over time until it stablized. Fifty-one percent of volunteers opened the nozzle to alleviate a feeling of stuffiness, and more than 50% adjusted the nozzle to improve upper body comfort. Over the period of the experiment the majority of volunteers chose to adjust their the air flow of their personal system. This confirms airline companies' decisions to install the individual aircraft ventilation systems in their aircraft indicates that personal air systems based on nozzle adjustment are essential for cabin comfort. These results will assist in the design of more efficient air distribution systems within passenger aircraft cabins where there is a need to optimize the air flow in order to efficiently improve aircraft passengers' thermal comfort and reduce energy use. Copyright © 2014 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Viper cabin-fuselage structural design concept with engine installation and wing structural design

NASA Technical Reports Server (NTRS)

Marchesseault, B.; Carr, D.; Mccorkle, T.; Stevens, C.; Turner, D.

1993-01-01

This report describes the process and considerations in designing the cabin, nose, drive shaft, and wing assemblies for the 'Viper' concept aircraft. Interfaces of these assemblies, as well as interfaces with the sections of the aircraft aft of the cabin, are also discussed. The results of the design process are included. The goal of this project is to provide a structural design which complies with FAR 23 requirements regarding occupant safety, emergency landing loads, and maneuvering loads. The design must also address the interfaces of the various systems in the cabin, nose, and wing, including the drive shaft, venting, vacuum, electrical, fuel, and control systems. Interfaces between the cabin assembly and the wing carrythrough and empennage assemblies were required, as well. In the design of the wing assemblies, consistency with the existing cabin design was required. The major areas considered in this report are materials and construction, loading, maintenance, environmental considerations, wing assembly fatigue, and weight. The first three areas are developed separately for the nose, cabin, drive shaft, and wing assemblies, while the last three are discussed for the entire design. For each assembly, loading calculations were performed to determine the proper sizing of major load carrying components. Table 1.0 lists the resulting margins of safety for these key components, along with the types of the loads involved, and the page number upon which they are discussed.

Cabin Noise Studies for the Orion Spacecraft Crew Module

NASA Technical Reports Server (NTRS)

Dandaroy, Indranil; Chu, S. Reynold; Larson, Lauren; Allen, Christopher S.

2010-01-01

Controlling cabin acoustic noise levels in the Crew Module (CM) of the Orion spacecraft is critical for adequate speech intelligibility, to avoid fatigue and to prevent any possibility of temporary and permanent hearing loss. A vibroacoustic model of the Orion CM cabin has been developed using Statistical Energy Analysis (SEA) to assess compliance with acoustic Constellation Human Systems Integration Requirements (HSIR) for the on-orbit mission phase. Cabin noise in the Orion CM needs to be analyzed at the vehicle-level to assess the cumulative acoustic effect of various Orion systems at the crewmember's ear. The SEA model includes all major structural and acoustic subsystems inside the CM including the Environmental Control and Life Support System (ECLSS), which is the primary noise contributor in the cabin during the on-orbit phase. The ECLSS noise sources used to excite the vehicle acoustic model were derived using a combination of established empirical predictions and fan development acoustic testing. Baseline noise predictions were compared against acoustic HSIR requirements. Key noise offenders and paths were identified and ranked using noise transfer path analysis. Parametric studies were conducted with various acoustic treatment packages in the cabin to reduce the noise levels and define vehicle-level mass impacts. An acoustic test mockup of the CM cabin has also been developed and noise treatment optimization tests were conducted to validate the results of the analyses.

Human Mars Ascent Configuration and Design Sensitivities

NASA Technical Reports Server (NTRS)

Polsgrove, Tara P.; Gernhardt, Mike; Collins, Tim; Martin, John

2017-01-01

Human missions to Mars may utilize several small cabins where crew members could live for days up to a couple of weeks. At the end of a Mars surface mission the Mars Ascent Vehicle (MAV) crew cabin would carry the crew to their destination in orbit in a matter of hours or days. Other small cabins in support of a Mars mission would include pressurized rovers that allow crew members to travel great distances from their primary habitat on Mars while unconstrained by time limits of typical EVAs. An orbital crew taxi could allow for exploration of the moons of Mars with minimum impact to the primary Earth-Mars transportation systems. A common crew cabin design that can perform in each of these applications is desired and could reduce the overall mission cost. However, for the MAV, the crew cabin size and mass can have a large impact on vehicle design and performance. The total ascent vehicle mass drives performance requirements for the Mars descent systems and the Earth to Mars transportation elements. Minimizing MAV mass is a priority and minimizing the crew cabin size and mass is one way to do that. This paper explores the benefits and impacts of using a common crew cabin design for the MAV. Results of a MAV configuration trade study will be presented along with mass and performance estimates for the selected design.

Bio-inspired, Moisture-Powered Hybrid Carbon Nanotube Yarn Muscles

PubMed Central

Kim, Shi Hyeong; Kwon, Cheong Hoon; Park, Karam; Mun, Tae Jin; Lepró, Xavier; Baughman, Ray H.; Spinks, Geoffrey M.; Kim, Seon Jeong

2016-01-01

Hygromorph artificial muscles are attractive as self-powered actuators driven by moisture from the ambient environment. Previously reported hygromorph muscles have been largely limited to bending or torsional motions or as tensile actuators with low work and energy densities. Herein, we developed a hybrid yarn artificial muscle with a unique coiled and wrinkled structure, which can be actuated by either changing relative humidity or contact with water. The muscle provides a large tensile stroke (up to 78%) and a high maximum gravimetric work capacity during contraction (2.17 kJ kg−1), which is over 50 times that of the same weight human muscle and 5.5 times higher than for the same weight spider silk, which is the previous record holder for a moisture driven muscle. We demonstrate an automatic ventilation system that is operated by the tensile actuation of the hybrid muscles caused by dew condensing on the hybrid yarn. This self-powered humidity-controlled ventilation system could be adapted to automatically control the desired relative humidity of an enclosed space. PMID:26973137

Effectiveness of Humidification with Heat and Moisture Exchanger-booster in Tracheostomized Patients.

PubMed

Gonzalez, Isabel; Jimenez, Pilar; Valdivia, Jorge; Esquinas, Antonio

2017-08-01

The two most commonly used types of humidifiers are heated humidifiers and heat and moisture exchange humidifiers. Heated humidifiers provide adequate temperature and humidity without affecting the respiratory pattern, but overdose can cause high temperatures and humidity resulting in condensation, which increases the risk of bacteria in the circuit. These devices are expensive. Heat and moisture exchanger filter is a new concept of humidification, increasing the moisture content in inspired gases. This study aims to determine the effectiveness of the heat and moisture exchanger (HME)-Booster system to humidify inspired air in patients under mechanical ventilation. We evaluated the humidification provided by 10 HME-Booster for tracheostomized patients under mechanical ventilation using Servo I respirators, belonging to the Maquet company and Evita 4. There was an increase in the inspired air humidity after 1 h with the humidifier. The HME-Booster combines the advantages of heat and moisture exchange minimizing the negatives. It increases the amount of moisture in inspired gas in mechanically ventilated tracheostomized patients. It is easy and safe to use. The type of ventilator used has no influence on the result.

Accelerated Testing and Modeling of Potential-Induced Degradation as a Function of Temperature and Relative Humidity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hacke, Peter; Spataru, Sergiu; Terwilliger, Kent

2015-06-14

An acceleration model based on the Peck equation was applied to power performance of crystalline silicon cell modules as a function of time and of temperature and humidity, the two main environmental stress factors that promote potential-induced degradation. This model was derived from module power degradation data obtained semi-continuously and statistically by in-situ dark current-voltage measurements in an environmental chamber. The modeling enables prediction of degradation rates and times as functions of temperature and humidity. Power degradation could be modeled linearly as a function of time to the second power; additionally, we found that coulombs transferred from the active cellmore » circuit to ground during the stress test is approximately linear with time. Therefore, the power loss could be linearized as a function of coulombs squared. With this result, we observed that when the module face was completely grounded with a condensed phase conductor, leakage current exceeded the anticipated corresponding degradation rate relative to the other tests performed in damp heat.« less

Condition Assessment of a Historic Trout Rearing Station in Upper Michigan

Treesearch

Frederico J. N. Franca; Tamara S.F. Amorin Franca; Lon A. Yeary; Christopher Hohnholt; John W. Forsman; Robert J. Ross

2015-01-01

Michigan Technological University's (Michigan Tech) School of Forest Resources and Environmental Science maintains a log cabin on the north branch of the Otter River in southern Houghton County (Portage Township), Michigan. The cabin was built in 1934-1935 and measures 150 m2. The cabin's location is less than 10 m from the river, and...

Determination of partition and diffusion coefficients of formaldehyde in selected building materials and impact of relative humidity.

PubMed

Xu, Jing; Zhang, Jianshun S; Liu, Xiaoyu; Gao, Zhi

2012-06-01

The partition and effective diffusion coefficients of formaldehyde were measured for three materials (conventional gypsum wallboard, "green" gypsum wallboard, and "green" carpet) under three relative humidity (RH) conditions (20%, 50%, and 70% RH). The "green" materials contained recycled materials and were friendly to environment. A dynamic dual-chamber test method was used. Results showed that a higher relative humidity led to a larger effective diffusion coefficient for two kinds of wallboards and carpet. The carpet was also found to be very permeable resulting in an effective diffusion coefficient at the same order of magnitude with the formaldehyde diffusion coefficient in air. The partition coefficient (K(ma)) of formaldehyde in conventional wallboard was 1.52 times larger at 50% RH than at 20% RH, whereas it decreased slightly from 50% to 70% RH, presumably due to the combined effects of water solubility of formaldehyde and micro-pore blocking by condensed moisture at the high RH level. The partition coefficient of formaldehyde increased slightly with the increase of relative humidity in "green" wallboard and "green" carpet. At the same relative humidity level, the "green" wallboard had larger partition coefficient and effective diffusion coefficient than the conventional wallboard, presumably due to the micro-pore structure differences between the two materials. The data generated could be used to assess the sorption effects of formaldehyde on building materials and to evaluate its impact on the formaldehyde concentration in buildings.

The influence of a heat and moisture exchanger on tracheal climate in a cold environment.

PubMed

Zuur, J Karel; Muller, Sara H; Vincent, Andrew; Sinaasappel, Michiel; de Jongh, Frans H C; Hilgers, Frans J M

2009-09-01

The incidence of pulmonary complaints, severe tracheitis and lung function deterioration is increased during wintertime in laryngectomized individuals. We analyzed how a heat and moisture exchanger (HME) performs in cold and dry ambient circumstances, and how its efficiency in this environmental climate might be improved. Randomized crossover. Intra-tracheal temperature and humidity were measured in 10 laryngectomized patients with and without HME, in a cold (mean, 4.7 degrees C) and dry (mean, 4.5 mgH2O/L) room. Presence of an HME causes the intra-tracheal mean humidity minima and maxima to increase with 4.2 mgH2O/L (95%CI: 3.3-5.0 mgH2O/L; p<0.001) and 2.4 mgH2O/L (95%CI: 1.7-3.1 mgH2O/L; p<0.001), respectively. The intra-tracheal mean temperature minima and maxima increased with 3.9 degrees C (95%CI: 2.7-5.1 degrees C; p<0.001) and 1.2 degrees C (95%CI: 0.8-1.2 degrees C; p<0.001), respectively. In the majority of patients, the calculated relative humidity values appear to reach well above 100% during inspiration. In a cold environment, presence of an HME significantly increases both inspiratory and expiratory temperature and humidity values. Relative humidity calculations suggest the formation of condense droplets during inspiration. To further increase its effectiveness, improvement of the HME's thermal capacity should be aimed for.

Cabin attendants’ exposure to vibration and shocks during landing

NASA Astrophysics Data System (ADS)

Burström, Lage; Lindberg, Lennart; Lindgren, Torsten

2006-12-01

The Scandinavian Airlines System (SAS) has noted that cabin attendants have reported an increase in health problems associated with landing. The European Union reports cover health problems related to neck, shoulder, and lower-back injuries. Moreover, analysis of these reports shows that the problems are often associated with specific airplanes that have a longer tail behind the rear wheels and appear more often in attendants who sit in the back of planes rather then the front. Against this background, this study measures and describes the vibration during landing in specific airplanes to evaluate the health risk for the cabin attendants. Measurements were conducted on regular flights with passengers in the type of airplane, Boeing 737-800, which was related to the highest per cent of reported health problems. All measurements were performed the same day during three landings in one airplane with the same pilots and cabin attendants. The measurements were carried out simultaneously on the cabin crew seats in the back and front of the passenger cabin. Under the cabin crew's seat cushions, a triaxiell seat-accelerometer was placed to measure the vibration in three axes. The signals from the accelerometers were amplified by charge amplifiers and stored on tape. The stored data were analysed with a computer-based analyse system. For the cabin attendants, the dominant direction for the vibration load during landing is the up-and-down direction although some vibration also occurs in the other horizontal directions. The exposure to vibration is higher on the rear crew seat compared to the front seat. For instance, both the vibration dose value (VDV) and the frequency-weighted acceleration in the dominant direction are more then 50% higher on the rear seat. The frequency-weighted acceleration and the VDV measured at the crew seats are below the exposure limits as described by the European vibration directive. The evaluation of the cabin attendants' exposure to multiple shocks during landing shows that the potential of an adverse health effect for the cabin attendants is low in the front of the airplane and increases to moderate in the rear. Although this is a limited study, it could be conclude that there could be a risk for cabin attendants due to the exposure of multiple shocks. Therefore, efforts should be spent to minimize their risk by developing a better seat cushion and back support to lessen the effects of shocks. In addition, attendants should be informed about the most suitable posture to take during landing.

4. VIEW OF EMPIRE, STONE CABIN AND TIP TOP MINES. ...

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

4. VIEW OF EMPIRE, STONE CABIN AND TIP TOP MINES. EMPIRE TAILING PILE IS VISIBLE IN LOWER CENTER (SLOPE WITH ORE CHUTE IS HIDDEN BY TREES ABOVE TAILINGS), TIP TOP IS VISIBLE IN RIGHT THIRD AND SLIGHTLY UPHILL IN ELEVATION FROM UPPER EMPIRE TAILINGS,(TO LOCATE, FIND THE V-SHAPED SPOT OF SNOW JUST BELOW THE RIDGE LINE ON FAR RIGHT OF IMAGE. TIP TOP BUILDING IS VISIBLE IN THE LIGHT AREA BELOW AND SLIGHTLY LEFT OF V-SHAPED SNOW SPOT), AND STONE CABIN II IS ALSO VISIBLE, (TO LOCATE, USE A STRAIGHT EDGE AND ALIGN WITH EMPIRE TAILINGS. THIS WILL DIRECT ONE THROUGH THE EDGE OF STONE CABIN II, WHICH IS THE DARK SPOT JUST BELOW THE POINT WHERE THE RIDGE LINE TREES STOP). STONE CABIN I IS LOCATED IN GENERAL VICINITY OF THE LONE TREE ON FAR LEFT RIDGE LINE. ... - Florida Mountain Mining Sites, Silver City, Owyhee County, ID

Ship cabin leakage alarm based on ARM SCM

NASA Astrophysics Data System (ADS)

Qu, Liyan

2018-03-01

If there is a leakage in the cabin of a sailing ship, it is a major accident that threatens the personnel and property of the ship. If we can’t take timely measures, there will be a devastating disaster. In order to judge the leakage of the cabin, it is necessary to set up a leakage alarm system, so as to achieve the purpose of detecting and alarming the leakage of the cabin, and avoid the occurrence of accidents. This paper discusses the design of ship cabin leakage alarm system based on ARM SCM. In order to ensure the stability and precision of the product, the hardware design of the alarm system is carried out, such as circuit design, software design, the programming of SCM, the software programming of upper computer, etc. It is hoped that it can be of reference value to interested readers.

Using Amphiphilic Nanostructures to Enable Long-Range Ensemble Coalescence and Surface Rejuvenation in Dropwise Condensation

DTIC Science & Technology

2012-01-01

in high-humidity environments. Nature-inspired superhydrophobic surfaces have been actively explored to enhance heat and mass transfer rates by...challenge with superhydrophobic surfaces, as observed in nature on the lotus leaf21 and on synthetic surfaces,22,23 is that they are often rendered...Dynamics. Rev. Mod. Phys. 1985, 57, 827–863. 2. Kim, S. H. Fabrication of Superhydrophobic Surfaces. J. Adhes. Sci. Technol. 2008, 22, 235–250. 3

[Heated humidification during CPAP with and without tube insulation].

PubMed

Rühle, K-H; Domanski, U; Schröder, M; Franke, K J; Nilius, G

2010-05-01

Patients with obstructive sleep apnoea syndrome (OSAS) under continuous positive pressure (CPAP) often complain about drying-up of the throat and nasal mucosa. In many cases the problem can be eliminated with a heated humidifier (WLB). Especially in a cold environment condensation forming on cooling of the air in the tube and the mask can be observed. To avoid this, some patients use an insulating tube covering. We investigated the effect of temperature (T) and relative humidity (rH) of the environment, the ventilation pressure, mask leaks, insulation of tubing on the T and rH% of the delivered air at the end of the tube or in the mask in OSAS patients. All measurements were performed with a conventional WLB (S8, Resmed Fa) and a temperature and humidity sensor (Fa Testo, Lenzkirch). 8 patients with OSAS were examined during the day at a room temperature of 16.4 degrees C. The temperature at the outlet of the WLB increased with a higher ambient temperature. Through isolation with a hose cover the temperature drop in the tube was reduced by 2.3 degrees C. By tube insulation a mean increase in temperature between 1.6 and 1.0 C during normal breathing in dependence on the leakage flow in the mask was found. Due to additional insulation with a tube cover the mask temperature can be increased, albeit slightly, and the formation of condensation is reduced.

Relations Between Cloud Condensation Nuclei And Aerosol Optical Properties Relevant to Remote Sensing: Airborne Measurements in Biomass Burning, Pollution and Dust Aerosol Over North America

NASA Astrophysics Data System (ADS)

Shinozuka, Y.; Clarke, A.; Howell, S.; Kapustin, V.; McNaughton, C.; Zhou, J.; Decarlo, P.; Jimenez, J.; Roberts, G.; Tomlinson, J.; Collins, D.

2008-12-01

Remote sensing of the concentration of cloud condensation nuclei (CCN) would help investigate the indirect effect of tropospheric aerosols on clouds and climate. In order to assess its feasibility, this paper evaluates the spectral-based retrieval technique for aerosol number and seeks one for aerosol solubility, using in-situ aircraft measurements of aerosol size distribution, chemical composition, hygroscopicity, CCN activity and optical properties. Our statistical analysis reveals that the CCN concentration over Mexico can be optically determined to a relative error of <20%, smaller than that for the mainland US and the surrounding oceans (~a factor of 2). Mexico's advantage is four-fold. Firstly, many particles originating from the lightly regulated industrial combustion and biomass burning are large enough to significantly affect light extinction, elevating the correlation between extinction and CCN number in absence of substantial dust. Secondly, the generally low ambient humidity near the major aerosol sources limits the error in the estimated response of particle extinction to humidity changes. Thirdly, because many CCN contain black carbon, light absorption also provides a measure of the CCN concentration. Fourthly, the organic fraction of volatile mass of submicron particles (OMF) is anti-correlated with the wavelength dependence of extinction due to preferential anion uptake by coarse dust, which provides a potential tool for remote-sensing OMF and the particle solubility.

Development of Pressure Swing Adsorption Technology for Spacesuit Carbon Dioxide and Humidity Removal

NASA Technical Reports Server (NTRS)

Papale, William; Paul, Heather; Thomas, Gretchen

2006-01-01

Metabolically produced carbon dioxide (CO2) removal in spacesuit applications has traditionally been accomplished utilizing non-regenerative Lithium Hydroxide (LiOH) canisters. In recent years, regenerative Metal Oxide (MetOx) has been developed to replace the Extravehicular Mobility Unity (EMU) LiOH canister for extravehicular activity (EVA) missions in micro-gravity, however, MetOx may carry a significant weight burden for potential use in future Lunar or planetary EVA exploration missions. Additionally, both of these methods of CO2 removal have a finite capacity sized for the particular mission profile. Metabolically produced water vapor removal in spacesuits has historically been accomplished by a condensing heat exchanger within the ventilation process loop of the suit life support system. Advancements in solid amine technology employed in a pressure swing adsorption system have led to the possibility of combining both the CO2 and humidity control requirements into a single, lightweight device. Because the pressure swing adsorption system is regenerated to space vacuum or by an inert purge stream, the duration of an EVA mission may be extended significantly over currently employed technologies, while markedly reducing the overall subsystem weight compared to the combined weight of the condensing heat exchanger and current regenerative CO2 removal technology. This paper will provide and overview of ongoing development efforts evaluating the subsystem size required to manage anticipated metabolic CO2 and water vapor generation rates in a spacesuit environment.

Gas uptake and chemical aging of semisolid organic aerosol particles

PubMed Central

Shiraiwa, Manabu; Ammann, Markus; Koop, Thomas; Pöschl, Ulrich

2011-01-01

Organic substances can adopt an amorphous solid or semisolid state, influencing the rate of heterogeneous reactions and multiphase processes in atmospheric aerosols. Here we demonstrate how molecular diffusion in the condensed phase affects the gas uptake and chemical transformation of semisolid organic particles. Flow tube experiments show that the ozone uptake and oxidative aging of amorphous protein is kinetically limited by bulk diffusion. The reactive gas uptake exhibits a pronounced increase with relative humidity, which can be explained by a decrease of viscosity and increase of diffusivity due to hygroscopic water uptake transforming the amorphous organic matrix from a glassy to a semisolid state (moisture-induced phase transition). The reaction rate depends on the condensed phase diffusion coefficients of both the oxidant and the organic reactant molecules, which can be described by a kinetic multilayer flux model but not by the traditional resistor model approach of multiphase chemistry. The chemical lifetime of reactive compounds in atmospheric particles can increase from seconds to days as the rate of diffusion in semisolid phases can decrease by multiple orders of magnitude in response to low temperature or low relative humidity. The findings demonstrate that the occurrence and properties of amorphous semisolid phases challenge traditional views and require advanced formalisms for the description of organic particle formation and transformation in atmospheric models of aerosol effects on air quality, public health, and climate. PMID:21690350

Engine bleed air reduction in DC-10

NASA Technical Reports Server (NTRS)

Newman, W. H.; Viele, M. R.

1980-01-01

An 0.8 percent fuel savings was achieved by a reduction in engine bleed air through the use of cabin air recirculation. The recirculation system was evaluated in revenue service on a DC-10. The cabin remained comfortable with reductions in cabin fresh air (engine bleed air) as much as 50 percent. Flight test verified the predicted fuel saving of 0.8 percent.

Effects of acoustic treatment on the interior noise levels of a twin-engine propeller aircraft - Experimental flight results and theoretical predictions

NASA Technical Reports Server (NTRS)

Beyer, T. B.; Powell, C. A.; Daniels, E. F.; Pope, L. D.

1984-01-01

In-flight noise level measurements were made within two cabin configurations of a general aviation business aircraft. The Fairchild Merlin IVC twin-engine aircraft was tested with bare walls and fiberglass insulation and in an executive trim configuration. Narrow-band and octave format data were subjected to analyses which permitted identification of the blade passage harmonics (BPH). Cabin noise level reductions (insertion losses) due to added insulation varied with position in the cabin, the BPH number, cabin pressure, and engine torque. The measurements were closely predicted using the propeller aircraft interior noise (PAIN) mode.

Development of Multi-Layered Floating Floor for Cabin Noise Reduction

NASA Astrophysics Data System (ADS)

Song, Jee-Hun; Hong, Suk-Yoon; Kwon, Hyun-Wung

2017-12-01

Recently, regulations pertaining to the noise and vibration environment of ship cabins have been strengthened. In this paper, a numerical model is developed for multi-layered floating floor to predict the structure-borne noise in ship cabins. The theoretical model consists of multi-panel structures lined with high-density mineral wool. The predicted results for structure-borne noise when multi-layered floating floor is used are compared to the measure-ments made of a mock-up. A comparison of the predicted results and the experimental one shows that the developed model could be an effective tool for predicting structure-borne noise in ship cabins.

Rationale and Methods for Archival Sampling and Analysis of Atmospheric Trace Chemical Contaminants On Board Mir and Recommendations for the International Space Station

NASA Technical Reports Server (NTRS)

Perry, J. L.; James, J. T.; Cole, H. E.; Limero, T. F.; Beck, S. W.

1997-01-01

Collection and analysis of spacecraft cabin air samples are necessary to assess the cabin air quality with respect to crew health. Both toxicology and engineering disciplines work together to achieve an acceptably clean cabin atmosphere. Toxicology is concerned with limiting the risk to crew health from chemical sources, setting exposure limits, and analyzing air samples to determine how well these limits are met. Engineering provides the means for minimizing the contribution of the various contaminant generating sources by providing active contamination control equipment on board spacecraft and adhering to a rigorous material selection and control program during the design and construction of the spacecraft. A review of the rationale and objectives for sampling spacecraft cabin atmospheres is provided. The presently-available sampling equipment and methods are reviewed along with the analytical chemistry methods employed to determine trace contaminant concentrations. These methods are compared and assessed with respect to actual cabin air quality monitoring needs. Recommendations are presented with respect to the basic sampling program necessary to ensure an acceptably clean spacecraft cabin atmosphere. Also, rationale and recommendations for expanding the scope of the basic monitoring program are discussed.

Development and testing of cabin sidewall acoustic resonators for the reduction of cabin tone levels in propfan-powered aircraft

NASA Technical Reports Server (NTRS)

Kuntz, H. L.; Gatineau, R. J.; Prydz, R. A.; Balena, F. J.

1991-01-01

The use of Helmholtz resonators to increase the sidewall transmission loss (TL) in aircraft cabin sidewalls is evaluated. Development, construction, and test of an aircraft cabin acoustic enclosure, built in support of the Propfan Test Assessment (PTA) program, is described. Laboratory and flight test results are discussed. Resonators (448) were located between the enclosure trim panels and the fuselage shell. In addition, 152 resonators were placed between the enclosure and aircraft floors. The 600 resonators were each tuned to a propfan fundamental blade passage frequency (235 Hz). After flight testing on the PTA aircraft, noise reduction (NR) tests were performed with the enclosure in the Kelly Johnson Research and Development Center Acoustics Laboratory. Broadband and tonal excitations were used in the laboratory. Tonal excitation simulated the propfan flight test excitation. The resonators increase the NR of the cabin walls around the resonance frequency of the resonator array. Increases in NR of up to 11 dB were measured. The effects of flanking, sidewall absorption, cabin absorption, resonator loading of trim panels, and panel vibrations are presented. Resonator and sidewall panel design and test are discussed.

Automobile exhaust as a means of suicide: an experimental study with a proposed model.

PubMed

Morgen, C; Schramm, J; Kofoed, P; Steensberg, J; Theilade, P

1998-07-01

Experiments were conducted to investigate the concentration of carbon monoxide (CO) in a car cabin under suicide attempts with different vehicles and different start situations, and a mathematical model describing the concentration of CO in the cabin was constructed. Three cars were set up to donate the exhaust. The first vehicle didn't have any catalyst, the second one was equipped with a malfunctioning three-way catalyst, and the third car was equipped with a well-functioning three-way catalyst. The three different starting situations were cold, tepid and warm engine start, respectively. Measurements of the CO concentrations were made in both the cabin and in the exhaust pipe. Lethal concentrations were measured in the cabin using all three vehicles as the donor car, including the vehicle with the well-functioning catalyst. The model results in most cases gave a good prediction of the CO concentration in the cabin. Four case studies of cars used for suicides were described. In each case measurements of CO were made in both the cabin and the exhaust under different starting conditions, and the mathematical model was tested on these cases. In most cases the model predictions were good.

Sustainable limitation of high-frequency oscillations of elevator cabin

NASA Astrophysics Data System (ADS)

Kaytukov, Batraz

2017-10-01

In this paper, a problem of sustainable limitation of vertical high-frequency oscillations of elevator cabin in buildings with various number of storeys is considered. To solve this problem, dynamic model of the elevator movement was developed. In the course of analytical and experimental studies, the main cause for emergence of undesirable high-frequency oscillations of a cabin was defined. The amplification factor which is the function of λ and length of cable was determined. The λ parameter is variable, and length of the cable changes depending on length passed by the cabin and is an amplification factor argument. For sustainable limitation of oscillations, use of dynamic dumper of lever type is proposed. Adjustment of the dumper natural vibration frequency in such a way that it is equal to the excitation frequency allows limiting of oscillations of the cabin and the elevator machine to reasonable value irrespective to position of a moving cabin in the shaft. Using dependences and plots which were obtained in the course of scientific analysis and experimental studies, reasonability of dumper application for sustainable limitation of high-frequency influence of the elevator machine on the base and obtaining of solutions of inertial forces equilibration problem was proved.

Irregular working hours and fatigue of cabin crew.

PubMed

Castro, Marta; Carvalhais, José; Teles, Júlia

2015-01-01

Beyond workload and specific environmental factors, flight attendants can be exposed to irregular working hours, conflicting with their circadian rhythms and having a negative impact in sleep, fatigue, health, social and family life, and performance which is critical to both safety and security in flight operations. This study focuses on the irregular schedules of cabin crew as a trigger of fatigue symptoms in a wet lease Portuguese airline. The aim was to analyze: what are the requirements of the cabin crew work; whether the schedules being observed and effective resting timeouts are triggering factors of fatigue; and the existence of fatigue symptoms in the cabin crew. A questionnaire has been adapted and applied to a sample of 73 cabin crew-members (representing 61.9% of the population), 39 females and 34 males, with an average age of 27.68 ± 4.27 years. Our data indicate the presence of fatigue and corresponding health symptoms among the airline cabin crew, despite of the sample favorable characteristics. Senior workers and women are more affected. Countermeasures are required. Recommendations can be made regarding the fatigue risk management, including work organization, education and awareness training programmes and specific countermeasures.

Experimental study of gaseous and particulate contaminants distribution in an aircraft cabin

NASA Astrophysics Data System (ADS)

Li, Fei; Liu, Junjie; Pei, Jingjing; Lin, Chao-Hsin; Chen, Qingyan

2014-03-01

The environment of the aircraft cabin greatly influences the comfort and health of passengers and crew members. Contaminant transport has a strong effect on disease spreading in the cabin environment. To obtain the complex cabin contaminant distribution fields accurately and completely, which is also essential to provide solid and precise data for computational fluid dynamics (CFD) model validation, this paper aimed to investigate and improve the method for simultaneous particle and gaseous contaminant fields measurement. The experiment was conducted in a functional MD-82 aircraft. Sulfur hexafluoride (SF6) was used as tracer gas, and Di-Ethyl-Hexyl-Sebacat (DEHS) was used as particulate contaminant. The whole measurement was completed in a part of the economy-class cabin without heating manikins or occupied with heating manikins. The experimental method, in terms of pollutant source setting, sampling points and schedule, was investigated. Statistical analysis showed that appropriately modified sampling grid was able to provide reasonable data. A small difference in the source locations can lead to a significant difference in cabin contaminant fields. And the relationship between gaseous and particulate pollutant transport was also discussed through tracking behavior analysis.

Particle backscatter and relative humidity measured across cirrus clouds and comparison with state-of-the-art cirrus modelling

NASA Astrophysics Data System (ADS)

Brabec, M.; Wienhold, F. G.; Luo, B.; Vömel, H.; Immler, F.; Steiner, P.; Peter, T.

2012-04-01

Advanced measurement and modelling techniques are employed to determine the partitioning of atmospheric water between the gas phase and the condensed phase in and around cirrus clouds, and thus to identify in-cloud and out-of-cloud supersaturations with respect to ice. In November 2008 the newly developed balloon-borne backscatter sonde COBALD (Compact Optical Backscatter and AerosoL Detector) was flown 14 times together with a CFH (Cryogenic Frost point Hygrometer) from Lindenberg, Germany (52° N, 14° E). The case discussed here in detail shows two cirrus layers with in-cloud relative humidities with respect to ice between 50% and 130%. Global operational analysis data of ECMWF (roughly 1° × 1° horizontal and 1 km vertical resolution, 6-hourly stored fields) fail to represent ice water contents and relative humidities. Conversely, regional COSMO-7 forecasts (6.6 km × 6.6 km, 5-min stored fields) capture the measured humidities and cloud positions remarkably well. The main difference between ECMWF and COSMO data is the resolution of small-scale vertical features responsible for cirrus formation. Nevertheless, ice water contents in COSMO-7 are still off by factors 2-10, likely reflecting limitations in COSMO's ice phase bulk scheme. Significant improvements can be achieved by comprehensive size-resolved microphysical and optical modelling along backward trajectories based on COSMO-7 wind and temperature fields, which allow accurate computation of humidities, ice particle size distributions and backscatter ratios at the COBALD wavelengths. However, only by superimposing small-scale temperature fluctuations, which remain unresolved by the NWP models, can we obtain a satisfying agreement with the observations and reconcile the measured in-cloud non-equilibrium humidities with conventional ice cloud microphysics.

Tuning orb spider glycoprotein glue performance to habitat humidity.

PubMed

Opell, Brent D; Jain, Dharamdeep; Dhinojwala, Ali; Blackledge, Todd A

2018-03-26

Orb-weaving spiders use adhesive threads to delay the escape of insects from their webs until the spiders can locate and subdue the insects. These viscous threads are spun as paired flagelliform axial fibers coated by a cylinder of solution derived from the aggregate glands. As low molecular mass compounds (LMMCs) in the aggregate solution attract atmospheric moisture, the enlarging cylinder becomes unstable and divides into droplets. Within each droplet an adhesive glycoprotein core condenses. The plasticity and axial line extensibility of the glycoproteins are maintained by hygroscopic LMMCs. These compounds cause droplet volume to track changes in humidity and glycoprotein viscosity to vary approximately 1000-fold over the course of a day. Natural selection has tuned the performance of glycoprotein cores to the humidity of a species' foraging environment by altering the composition of its LMMCs. Thus, species from low-humidity habits have more hygroscopic threads than those from humid forests. However, at their respective foraging humidities, these species' glycoproteins have remarkably similar viscosities, ensuring optimal droplet adhesion by balancing glycoprotein adhesion and cohesion. Optimal viscosity is also essential for integrating the adhesion force of multiple droplets. As force is transferred to a thread's support line, extending droplets draw it into a parabolic configuration, implementing a suspension bridge mechanism that sums the adhesive force generated over the thread span. Thus, viscous capture threads extend an orb spider's phenotype as a highly integrated complex of large proteins and small molecules that function as a self-assembling, highly tuned, environmentally responsive, adhesive biomaterial. Understanding the synergistic role of chemistry and design in spider adhesives, particularly the ability to stick in wet conditions, provides insight in designing synthetic adhesives for biomedical applications. © 2018. Published by The Company of Biologists Ltd.

Anomalous water expulsion from carbon-based rods at high humidity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nune, Satish K.; Lao, David B.; Heldebrant, David J.

Managing water is critical for industrial applications including CO2 capture, catalysis, bio-oil separations and energy storage. Various classes of materials have been designed for these applications, achieving specific water adsorption capacities at a given relative humidity (RH). Three water adsorption-desorption mechanisms are common to inorganic materials: (1) chemisorption, which may lead to the modification of the first coordination sphere; (2) simple adsorption, which is reversible in nature; or (3) capillary condensation, which is irreversible in nature. Regardless of sorption mechanism, all materials known today increase water adsorption capacity with increasing RH; none exhibit repeated adsorption of water at low humiditymore » and release at high humidity. We present here a material that breaks from this convention: a new class of nitrogen containing carbon rods along with nonstoichiometric FeXSY that adsorb water at low humidity, and spontaneously expel half of the adsorbed water when the RH exceeds a 50–80% threshold. Monolayers of water form on the surfaces of the carbon rods, with the amount of water adsorbed directly linked to the aspect ratio of the rods and the available surface area. This unprecedented water expulsion is a reversible physical process. Once a complete monolayer is formed, adjacent rods in the bundles begin to adhere together via formation of a bridging monolayer, reducing the surface area available for water to adhere to. We believe the unique surface chemistry of these carbon rods can be used on other functionalized materials. Such behaviour offers a paradigm shift in water purification and separation: water could be repeatedly adsorbed from a low humidity vapour stream and then expelled into a pure water vapour stream, or humidity-responsive membranes could change their water permeance or selectivity as a function of RH.« less

Development of a Low-Power CO2 Removal and Compression System for Closed-Loop Air Revitalization in Future Spacecraft

NASA Technical Reports Server (NTRS)

Mulloth, Lila M.; Rosen, Micha; Affleck, David; LeVan, M. Douglas; Moate, Joe R.

2005-01-01

The current CO2 removal technology of NASA is very energy intensive and contains many non-optimized subsystems. This paper discusses the design and prototype development of a two-stage CO2 removal and compression system that will utilize much less power than NASA s current CO2 removal technology. This integrated system contains a Nafion membrane followed by a residual water adsorber that performs the function of the desiccant beds in the four-bed molecular sieve (4BMS) system of the International Space Station (ISS). The membrane and the water adsorber are followed by a two-stage CO2 removal and compression subsystem that satisfies the operations of the CO2 adsorbent beds of the 4BMS aid the interface compressor for the Sabatier reactor connection. The two-stage compressor will utilize the principles of temperature-swing adsorption (TSA) compression technology for CO2 removal and compression. The similarities in operation and cycle times of the CO2 removal (first stage) and compression (second stage) operations will allow thermal coupling of the processes to maximize the efficiency of the system. In addition to the low-power advantage, this processor will maintain a lower CO2 concentration in the cabin than that can be achieved by the existing CO2 removal systems. The compact, consolidated, configuration of membrane gas dryer and CO2 separator and compressor will allow continuous recycling of humid air in the cabin and supply of compressed CO2 to the reduction unit for oxygen recovery. The device has potential application to the International Space Station and future, long duration, transit, and planetary missions.

Airline Chair-rest Deconditioning: Induction of Immobilization Thromboemboli?

NASA Technical Reports Server (NTRS)

Greenleaf, J. E.; Rehrer, N. J.; Mohler, S. R.; Quach, D. T.; Evans, D. G.; Dalton, Bonnie P. (Technical Monitor)

2002-01-01

Air passenger miles will likely double by year 2020. The altered and restrictive environment in an airliner cabin can influence hematological homeostasis in passengers and crew. Flight-related deep various thromboemboli (DVT) have been associated with at least 577 deaths on 42 of 120 airlines from 1977 to 1984 (25 deaths/million departures), whereas many such cases go unreported. However, there are four major factors that could influence formation of possible flight-induced DVT: sleeping accomodations (via sitting immobilization), travelers' medical history (via tissue injury), cabin environmental factors (via lower partial pressure of oxygen and lower relative humidity), and the more encompassing chair-rest deconditioning (C-RD) syndrome. There is ample evidence that recent injury and surgery (especially in deconditioned hospitalized patients) facilitate thrombophlebitis and formation of DVT that may be exacerbated by the immobilization of prolonged air travel. In the healthy flying population immobilization factors associated with prolonged (> 5 hr) C-RID such as total body dehydration, hypovolemia and increased blood viscosity, and reduced various blood flow (pooling) in the legs may facilitate formation of DVT. However, data from at least four case-controlled epidemiological studies did not confirm a direct causative relationship between air travel and DART, but factors such as history of vascular thromboemboli, various insufficiency, chronic heart failure, obesity, immobile standing position, more than 3 pregnancies, infectious disease, long-distance travel, muscular trauma and violent physical effort were significantly more frequent in DVT patients than in controls. Thus, there is no clear, direct evidence yet that prolonged sitting in airliner seats, or prolonged experimental chair-rest- or bed- rest-deconditioning treatments cause deep various thromboemboli in healthy people.

Formation of nanoscale water bridges

NASA Astrophysics Data System (ADS)

Riedo, Elisa; Szoszkiewicz, Robert; Li, Tai-De; Gao, Jianping; Landman, Uzi

2006-03-01

The water bridges provide stability to sand castles, act as transport channels for dip-pen nanolitography and increase adhesion and friction in micro- and nano- devices such as MEMS. The kinetics of capillary condensation and growth at the nanoscale is studied here using friction force microscopy and molecular dynamics calculations. At 40% relative humidity we find that the meniscus nucleation times increase from 0.7 ms up to 4.2 ms when the temperature decreases from 332 K to 299 K. The nucleation times grow exponentially with the inverse temperature 1/T obeying an Arrhenius law. We obtain a nucleation energy barrier of 7.8*10̂-20˜J and an attempt frequency ranging between 4-250˜GHz, in excellent agreement with theoretical predictions. These results provide direct experimental evidence that capillary condensation is a thermally activated phenomenon.

Microbial Anomalies Encountered on the International Space Station

NASA Technical Reports Server (NTRS)

Bruce, Rebekah J.; Wong, Wing; Pierson, Duane; Castro, Victoria

2010-01-01

Microorganisms in our living environments are unavoidable. A community of microbes arrived in space with the delivery of the first element of the International Space Station (ISS), attached to hardware and on the bodies of the humans tasked with the initial assembly missions. The risk that microorganisms could cause adverse effects in the health of both the human occupants of the ISS as well as the physical integrity of the station environment and life support systems has been both a driver and a function of engineering and operational controls. Scientists and engineers at NASA have gone to extensive measures to control microbial growth at levels safe for the crewmembers and the spacecraft environment. Many of these measures were initiated with the design of the spacecraft and its systems. Materials used in the ISS were tested for resistance to fungi, such as mold and a paint with a fungus-killing chemical was also used. Controlling the humidity of the air in the Station is also an effective way of discouraging microbe growth. The breathing air is reconditioned by the Environmental Control Life Support System (ECLSS) prior to distribution, utilizing High Efficiency Particulate Air (HEPA) filtration. Requirements restricting the accumulation of water condensate in the air handlers and habitable volume of the ISS were other safeguards added. Water for drinking and food rehydration is disinfected or filtered. A robust in-flight housekeeping regimen for the ISS significantly reduces inappropriate growth of microorganisms and includes a regular cleaning of accessible surfaces with disinfectant wipes. Most of these requirements were suggested by microbiologists to mitigate and possibly prevent many microbiological risks. In addition to these controls, before flight monitoring and analyses of the cabin air, exposed surfaces, water and food, consumables, and crew members are conducted to mitigate microbial risk to the crew and spacecraft. Many microbial risks are much easier to identify and resolve before launch than during space flight. Although the focus has been on prevention of microbiologically related, not all problems can be anticipated. A number of microbial anomalies have occurred on ISS. This paper will discuss the occurrences, root-cause investigations, and mitigation steps taken to remediate the contamination.

2. General view of Fort Hill Farm, view looking north ...

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

2. General view of Fort Hill Farm, view looking north from (F) two-room cabin. From left to right, buildings visible are (I) log tobacco barn; (H and D) shed and center chimney four-room cabin; (E and (A) one-room cabin in front of mansion; (J) hay barn. - Fort Hill Farm, West of Staunton (Roanoke) River between Turkey & Caesar's Runs, Clover, Halifax County, VA

Effect of tubing condensate on non-invasive positive pressure ventilators tested under simulated clinical conditions.

PubMed

Hart, Diana Elizabeth; Forman, Mark; Veale, Andrew G

2011-09-01

Water condensate in the humidifier tubing can affect bi-level ventilation by narrowing tube diameter and increasing airflow resistance. We investigated room temperature and tubing type as ways to reduce condensate and its effect on bi-level triggering and pressure delivery. In this bench study, the aim was to test the hypothesis that a relationship exists between room temperature and tubing condensate. Using a patient simulator, a Res-med bi-level device was set to 18/8 cm H(2)O and run for 6 h at room temperatures of 16°C, 18°C and 20°C. The built-in humidifier was set to a low, medium or high setting while using unheated or insulated tubing or replaced with a humidifier using heated tubing. Humidifier output, condensate, mask pressure and triggering delay of the bi-level were measured at 1 and 6 h using an infrared hygrometer, metric weights, Honeywell pressure transducer and TSI pneumotach. When humidity output exceeded 17.5 mg H(2)O/L, inspiratory pressure fell by 2-15 cm H(2)O and triggering was delayed by 0.2-0.9 s. Heating the tubing avoided any such ventilatory effect whereas warmer room temperatures or insulating the tubing were of marginal benefit. Users of bi-level ventilators need to be aware of this problem and its solution. Bi-level humidifier tubing may need to be heated to ensure correct humidification, pressure delivery and triggering.

[Aerotoxic syndrome: fact or fiction?].

PubMed

de Graaf, Leroy J; Hageman, Gerard; Gouders, Bernie C M; Mulder, Michel F A

2014-01-01

Although the air from the turbine engines of commercial jet aircraft is used chiefly for propulsion some is also used to refresh and replenish air in the cabin. As a result of oil-seal leakage, pyrolysed engine oil or lubricating oil can contaminate cabin air via the aircraft's ventilation system, and flight crew and passengers can then inhale the combusted fumes. Exposure to emissions from cabin air, whether polluted or not, is associated with certain health risks. This phenomenon is known as the aerotoxic syndrome or 'cabin contamination'. The symptoms are non-specific, consisting predominantly of fatigue and mild cognitive impairment. Possible adverse health effects are attributed factors including organophosphate tricresyl phosphate, a component of aircraft engine oil that is potently neurotoxic.

Light aircraft sound transmission studies - Noise reduction model

NASA Technical Reports Server (NTRS)

Atwal, Mahabir S.; Heitman, Karen E.; Crocker, Malcolm J.

1987-01-01

Experimental tests conducted on the fuselage of a single-engine Piper Cherokee light aircraft suggest that the cabin interior noise can be reduced by increasing the transmission loss of the dominant sound transmission paths and/or by increasing the cabin interior sound absorption. The validity of using a simple room equation model to predict the cabin interior sound-pressure level for different fuselage and exterior sound field conditions is also presented. The room equation model is based on the sound power flow balance for the cabin space and utilizes the measured transmitted sound intensity data. The room equation model predictions were considered good enough to be used for preliminary acoustical design studies.

Status of candidate materials for full-scale tests in the 737 fuselage

NASA Technical Reports Server (NTRS)

Supkis, D.

1979-01-01

The test program has the objectives to: (1) increase passenger evacuation time to a minimum of five minutes from commercial aircraft in case of a fire; (2) prevent an external fire from entering closed cabins for five minutes by using fire barrier materials in the exterior wall; (3) demonstrate that a closed cabin will not reach 400 F; and (4) prove that a fire near a cabin opening will not propagate through the cabin for a minimum of five minutes. The materials status is outlined for seat cushions, upholstery and associated seat materials, wall and ceiling panels, floor panels, carpet and carpet underlay, windows, cargo bay liners, insulation bagging, and thermal acoustical insulation.

Evaluation of Humidity Control Options in Hot-Humid Climate Homes (Fact Sheet)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

2011-12-01

This technical highlight describes NREL research to analyze the indoor relative humidity in three home types in the hot-humid climate zone, and examine the impacts of various dehumidification equipment and controls. As the Building America program researches construction of homes that achieve greater source energy savings over typical mid-1990s construction, proper modeling of whole-house latent loads and operation of humidity control equipment has become a high priority. Long-term high relative humidity can cause health and durability problems in homes, particularly in a hot-humid climate. In this study, researchers at the National Renewable Energy Laboratory (NREL) used the latest EnergyPlus toolmore » equipped with the moisture capacitance model to analyze the indoor relative humidity in three home types: a Building America high-performance home; a mid-1990s reference home; and a 2006 International Energy Conservation Code (IECC)-compliant home in hot-humid climate zones. They examined the impacts of various dehumidification equipment and controls on the high-performance home where the dehumidification equipment energy use can become a much larger portion of whole-house energy consumption. The research included a number of simulated cases: thermostat reset, A/C with energy recovery ventilator, heat exchanger assisted A/C, A/C with condenser reheat, A/C with desiccant wheel dehumidifier, A/C with DX dehumidifier, A/C with energy recovery ventilator, and DX dehumidifier. Space relative humidity, thermal comfort, and whole-house source energy consumption were compared for indoor relative humidity set points of 50%, 55%, and 60%. The study revealed why similar trends of high humidity were observed in all three homes regardless of energy efficiency, and why humidity problems are not necessarily unique in the high-performance home. Thermal comfort analysis indicated that occupants are unlikely to notice indoor humidity problems. The study confirmed that supplemental dehumidification is needed to maintain space relative humidity (RH) below 60% in a hot-humid climate home. Researchers also concluded that while all the active dehumidification options included in the study successfully controlled space relative humidity excursions, the increase in whole-house energy consumption was much more sensitive to the humidity set point than the chosen technology option. In the high-performance home, supplemental dehumidification equipment results in a significant source energy consumption penalty at 50% RH set point (12.6%-22.4%) compared to the consumption at 60% RH set point (1.5%-2.7%). At 50% and 55% RH set points, A/C with desiccant wheel dehumidifier and A/C with ERV and high-efficiency DX dehumidifier stand out as the two cases resulting in the smallest increase of source energy consumption. At an RH set point of 60%, all explicit dehumidification technologies result in similar insignificant increases in source energy consumption and thus are equally competitive.« less

Procedures for estimating the frequency of commercial airline flights encountering high cabin ozone levels

NASA Technical Reports Server (NTRS)

Holdeman, J. D.

1979-01-01

Three analytical problems in estimating the frequency at which commercial airline flights will encounter high cabin ozone levels are formulated and solved: namely, estimating flight-segment mean levels, estimating maximum-per-flight levels, and estimating the maximum average level over a specified flight interval. For each problem, solution procedures are given for different levels of input information - from complete cabin ozone data, which provides a direct solution, to limited ozone information, such as ambient ozone means and standard deviations, with which several assumptions are necessary to obtain the required estimates. Each procedure is illustrated by an example case calculation that uses simultaneous cabin and ambient ozone data obtained by the NASA Global Atmospheric Sampling Program. Critical assumptions are discussed and evaluated, and the several solutions for each problem are compared. Example calculations are also performed to illustrate how variations in lattitude, altitude, season, retention ratio, flight duration, and cabin ozone limits affect the estimated probabilities.

Full-scale flammability test data for validation of aircraft fire mathematical models

NASA Technical Reports Server (NTRS)

Kuminecz, J. F.; Bricker, R. W.

1982-01-01

Twenty-five large scale aircraft flammability tests were conducted in a Boeing 737 fuselage at the NASA Johnson Space Center (JSC). The objective of this test program was to provide a data base on the propagation of large scale aircraft fires to support the validation of aircraft fire mathematical models. Variables in the test program included cabin volume, amount of fuel, fuel pan area, fire location, airflow rate, and cabin materials. A number of tests were conducted with jet A-1 fuel only, while others were conducted with various Boeing 747 type cabin materials. These included urethane foam seats, passenger service units, stowage bins, and wall and ceiling panels. Two tests were also included using special urethane foam and polyimide foam seats. Tests were conducted with each cabin material individually, with various combinations of these materials, and finally, with all materials in the cabin. The data include information obtained from approximately 160 locations inside the fuselage.

Identification and proposed control of helicopter transmission noise at the source

NASA Technical Reports Server (NTRS)

Coy, John J.; Handschuh, Robert F.; Lewicki, David G.; Huff, Ronald G.; Krejsa, Eugene A.; Karchmer, Allan M.

1987-01-01

Helicopter cabin interiors require noise treatment which is expensive and adds weight. The gears inside the main power transmission are major sources of cabin noise. Work conducted by the NASA Lewis Research Center in measuring cabin interior noise and in relating the noise spectrum to the gear vibration of the Army OH-58 helicopter is described. Flight test data indicate that the planetary gear train is a major source of cabin noise and that other low frequency sources are present that could dominate the cabin noise. Companion vibration measurements were made in a transmission test stand, revealing that the single largest contributor to the transmission vibration was the spiral bevel gear mesh. The current understanding of the nature and causes of gear and transmission noise is discussed. It is believed that the kinematical errors of the gear mesh have a strong influence on that noise. The completed NASA/Army sponsored research that applies to transmission noise reduction is summarized. The continuing research program is also reviewed.

Noise level reduction inside helicopter cabins

NASA Astrophysics Data System (ADS)

Laudien, Eckehard; Niesl, George

1990-09-01

A number of measures to reduce the noise level in helicopter cabins are discussed. Laboratory test results of various panellings are presented as well as the insulation capacities of different panel mounts. Experiments in acoustic facilities (anechoic chamber and reverberation room) with the original cabin door and its frame led to an optimization of the transmission losses of door components such as window, sealing, and frame. The reduction of the cabin noise level by adding absorption is illustrated in the case of a honeycomb bulkhead with Helmholtz resonators. These sound absorption elements were designed to damp discrete gearbox frequencies. Resonators were also used for noise attenuation of an oil cooler fan. Cabin noise comfort can be improved by eliminating discrete frequencies. This was achieved in an experimental set up where properly tuned resonators were placed as close as possible to the passenger's ear in the headrest of the seat. In order to reduce structureborne transmission system noise, ground and flight test data of gearbox strut impedance were used for the design of specially tuned vibration absorbers.

Workspace design for crane cabins applying a combined traditional approach and the Taguchi method for design of experiments.

PubMed

Spasojević Brkić, Vesna K; Veljković, Zorica A; Golubović, Tamara; Brkić, Aleksandar Dj; Kosić Šotić, Ivana

2016-01-01

Procedures in the development process of crane cabins are arbitrary and subjective. Since approximately 42% of incidents in the construction industry are linked to them, there is a need to collect fresh anthropometric data and provide additional recommendations for design. In this paper, dimensioning of the crane cabin interior space was carried out using a sample of 64 crane operators' anthropometric measurements, in the Republic of Serbia, by measuring workspace with 10 parameters using nine measured anthropometric data from each crane operator. This paper applies experiments run via full factorial designs using a combined traditional and Taguchi approach. The experiments indicated which design parameters are influenced by which anthropometric measurements and to what degree. The results are expected to be of use for crane cabin designers and should assist them to design a cabin that may lead to less strenuous sitting postures and fatigue for operators, thus improving safety and accident prevention.

Identification and proposed control of helicopter transmission noise at the source

NASA Technical Reports Server (NTRS)

Coy, John J.; Handschuh, Robert F.; Lewicki, David G.; Huff, Ronald G.; Krejsa, Eugene A.; Karchmer, Allan M.; Coy, John J.

1988-01-01

Helicopter cabin interiors require noise treatment which is expensive and adds weight. The gears inside the main power transmission are major sources of cabin noise. Work conducted by the NASA Lewis Research Center in measuring cabin interior noise and in relating the noise spectrum to the gear vibration of the Army OH-58 helicopter is described. Flight test data indicate that the planetary gear train is a major source of cabin noise and that other low frequency sources are present that could dominate the cabin noise. Companion vibration measurements were made in a transmission test stand, revealing that the single largest contributor to the transmission vibration was the spiral bevel gear mesh. The current understanding of the nature and causes of gear and transmission noise is discussed. It is believed that the kinematical errors of the gear mesh have a strong influence on that noise. The completed NASA/Army sponsored research that applies to transmission noise reduction is summarized. The continuing research program is also reviewed.

Perceptual aspects of reproduced sound in car cabin acoustics.

PubMed

Kaplanis, Neofytos; Bech, Søren; Tervo, Sakari; Pätynen, Jukka; Lokki, Tapio; van Waterschoot, Toon; Jensen, Søren Holdt

2017-03-01

An experiment was conducted to determine the perceptual effects of car cabin acoustics on the reproduced sound field. In-car measurements were conducted whilst the cabin's interior was physically modified. The captured sound fields were recreated in the laboratory using a three-dimensional loudspeaker array. A panel of expert assessors followed a rapid sensory analysis protocol, the flash profile, to perceptually characterize and evaluate 12 acoustical conditions of the car cabin using individually elicited attributes. A multivariate analysis revealed the panel's consensus and the identified perceptual constructs. Six perceptual constructs characterize the differences between the acoustical conditions of the cabin, related to bass, ambience, transparency, width and envelopment, brightness, and image focus. The current results indicate the importance of several acoustical properties of a car's interior on the perceived sound qualities. Moreover, they signify the capacity of the applied methodology in assessing spectral and spatial properties of automotive environments in laboratory settings using a time-efficient and flexible protocol.

Fourth Aircraft Interior Noise Workshop

NASA Technical Reports Server (NTRS)

Stephens, David G. (Compiler)

1992-01-01

The fourth in a series of NASA/SAE Interior Noise Workshops was held on May 19 and 20, 1992. The theme of the workshop was new technology and applications for aircraft noise with emphasis on source noise prediction; cabin noise prediction; cabin noise control, including active and passive methods; and cabin interior noise procedures. This report is a compilation of the presentations made at the meeting which addressed the above issues.

36 CFR 13.146 - Use and occupancy of a cabin between December 18, 1973 and December 1, 1978.

Code of Federal Regulations, 2010 CFR

2010-07-01

... between December 18, 1973 and December 1, 1978. 13.146 Section 13.146 Parks, Forests, and Public Property...-Cabin Not Under Valid Lease Or Permit As of December 1, 1978 § 13.146 Use and occupancy of a cabin... may issue and extend such permit for a term not to exceed December 1, 1999 for such reasons as are...

Effect of cabin ventilation rate on ultrafine particle exposure inside automobiles.

PubMed

Knibbs, Luke D; de Dear, Richard J; Morawska, Lidia

2010-05-01

We alternately measured on-road and in-vehicle ultrafine (<100 nm) particle (UFP) concentration for 5 passenger vehicles that comprised an age range of 18 years. A range of cabin ventilation settings were assessed during 301 trips through a 4 km road tunnel in Sydney, Australia. Outdoor air flow (ventilation) rates under these settings were quantified on open roads using tracer gas techniques. Significant variability in tunnel trip average median in-cabin/on-road (I/O) UFP ratios was observed (0.08 to approximately 1.0). Based on data spanning all test automobiles and ventilation settings, a positive linear relationship was found between outdoor air flow rate and I/O ratio, with the former accounting for a substantial proportion of variation in the latter (R(2) = 0.81). UFP concentrations recorded in-cabin during tunnel travel were significantly higher than those reported by comparable studies performed on open roadways. A simple mathematical model afforded the ability to predict tunnel trip average in-cabin UFP concentrations with good accuracy. Our data indicate that under certain conditions, in-cabin UFP exposures incurred during tunnel travel may contribute significantly to daily exposure. The UFP exposure of automobile occupants appears strongly related to their choice of ventilation setting and vehicle.

Determination of organic carbon and ionic accountability of various waste and product waters derived from ECLSS water recovery tests and Spacelab humidity condensate

NASA Technical Reports Server (NTRS)

Carter, Donald L.; Cole, Harold; Habercom, Mark; Griffith, Guy

1992-01-01

The development of a closed-loop water recovery system for Space Station Freedom involves many technical challenges associated with contaminant removal. Attention is presently given to the characterization of contaminants constituting total organic carbon (TOC), and to the Hubaux and Vos (1970) statistical model for low level TOC that has been employed. A tabulation is given for TOC accountability in the case of both potable and hygiene waters.

A low cost hermetic packaging for high power industry fiber lasers

NASA Astrophysics Data System (ADS)

Ding, Jianwu; Liu, Jinhui

2018-02-01

For water-cooled fiber lasers, humidity and the resulting water-condensation has always been the biggest threat for laser reliability or power degradation, especially when used in harsh industrial environment. Here we present an innovative fiber laser packaging method featuring cast aluminum frame and an almost screw-free exterior packaging. A CW fiber laser with 1.5KW laser output power in such a compact and light-weight package has been demonstrated with an excellent beam quality and power stability for industry applications.

Photocatalytic post-treatment in waste water reclamation systems

NASA Technical Reports Server (NTRS)

Cooper, Gerald; Ratcliff, Matthew A.; Verostko, Charles E.

1989-01-01

A photocatalytic water purification process is described which effectively oxidizes organic impurities common to reclaimed waste waters and humidity condensates to carbon dioxide at ambient temperatures. With this process, total organic carbon concentrations below 500 ppb are readily achieved. The temperature dependence of the process is well described by the Arrhenius equation and an activation energy barrier of 3.5 Kcal/mole. The posttreatment approach for waste water reclamation described here shows potential for integration with closed-loop life support systems.

Sensitivity of nephelometric method for the investigation of condensation processes in submicron aerosol

NASA Astrophysics Data System (ADS)

Panchenko, Mikhail V.; Sviridenkov, Mikhail A.; Terpugova, Svetlana A.

2004-02-01

The possiblities to study the aerosol transformation with the artificial change fo the relative humidity, using the data of polarization and nephelometer measurements are discussed. It is shown that the set of parameters, measured by FAN nephelometer enable to retrieve the aerosol size distribution at different stages of humidification in the size range from 0.07 to 0.6-0.8 μm. The uncertainty in the estimation of the refractive index is within 0.02.

Computational and experimental study of atmospheric moisture in ceramic blocks filled with waste fibres in winter season

NASA Astrophysics Data System (ADS)

Stastnik, S.

2016-06-01

Development of materials for vertical outer building structures tends to application of hollow clay blocks filled with some appropriate insulation material. Ceramic fittings provide high thermal resistance, but the walls built from them suffer from condensation of air humidity in winter season frequently. The paper presents the computational simulation and experimental laboratory validation of moisture behaviour of such masonry with insulation prepared from waste fibres under the Central European climatic conditions.

Advanced air revitalization for optimized crew and plant environments

NASA Technical Reports Server (NTRS)

Lee, M. G.; Grigger, David J.; Brown, Mariann F.

1991-01-01

The Hybrid Air Revitalization System (HARS) closed ecosystem concept presented encompasses electrochemical CO2 and O2 separators, in conjunction with a mechanical condenser/separator for maintaining CO2, O2, and humidity levels in crew and plant habitats at optimal conditions. HARS requires no expendables, and allows flexible process control on the bases of electrochemical cell current, temperature, and airflow rate variations. HARS capacity can be easily increased through the incorporation of additional chemical cells. Detailed system flowcharts are provided.

Speech Signal Processing Research. Appendices 1 thru 9

DTIC Science & Technology

1975-12-01

is 2400 rpm for a maximum rotational latency of 25 ms and an average of 12.5 ms. The track to track access time is 12 ms, the average access time...in Table 1-3. Table 1-3. Capabilities and Limitations Description Characteristics Start-Up Time Operating Temperature Operating Humidity...Storage Conditions - - ■ ■ ■ -*****•******* ~40 seconds 0oC (320F) to +50oC (1220F) ambient 10% to 80% with no condensation Temperature =0oC(32oF) to

Electrochemical carbon dioxide concentrator subsystem development

NASA Technical Reports Server (NTRS)

Koszenski, E. P.; Heppner, D. B.; Bunnell, C. T.

1986-01-01

The most promising concept for a regenerative CO2 removal system for long duration manned space flight is the Electrochemical CO2 Concentrator (EDC), which allows for the continuous, efficient removal of CO2 from the spacecraft cabin. This study addresses the advancement of the EDC system by generating subsystem and ancillary component reliability data through extensive endurance testing and developing related hardware components such as electrochemical module lightweight end plates, electrochemical module improved isolation valves, an improved air/liquid heat exchanger and a triple redundant relative humidity sensor. Efforts included fabrication and testing the EDC with a Sabatier CO2 Reduction Reactor and generation of data necessary for integration of the EDC into a space station air revitalization system. The results verified the high level of performance, reliability and durability of the EDC subsystem and ancillary hardware, verified the high efficiency of the Sabatier CO2 Reduction Reactor, and increased the overall EDC technology engineering data base. The study concluded that the EDC system is approaching the hardware maturity levels required for space station deployment.

Thermal and fluid simulation of the environment under the dashboard, compared with measurement data

NASA Astrophysics Data System (ADS)

Popescu, C. S.; Sirbu, G. M.; Nita, I. C.

2017-10-01

The development of vehicles during the last decade is related to the evolution of electronic systems added in order to increase the safety and the number of services available on board, such as advanced driver-assistance systems (ADAS). Cars already have a complex computer network, with electronic control units (ECUs) connected to each other and receiving information from many sensors. The ECUs transfer an important heat power to the environment, while proper operating conditions need to be provided to ensure their reliability at high and low temperature, vibration and humidity. In a car cabin, electronic devices are usually placed in the compartment under the dashboard, an enclosed space designed for functional purposes. In the early stages of the vehicle design it has become necessary to analyse the environment under dashboard, by the use of Computational Fluid Dynamics (CFD) simulations and measurements. This paper presents the cooling of heat sinks by natural convection, a thermal and fluid simulation of the environment under the dashboard compared with test data.

Testing of an Amine-Based Pressure-Swing System for Carbon Dioxide and Humidity Control

NASA Technical Reports Server (NTRS)

Lin, Amy; Smith, Frederick; Sweterlitsch, Jeffrey; Graf, John; Nalette, Tim; Papale, William; Campbell, Melissa; Lu, Sao-Dung

2007-01-01

In a crewed spacecraft environment, atmospheric carbon dioxide (CO2) and moisture control is crucial. Hamilton Sundstrand has developed a stable and efficient amine-based CO2 and water vapor sorbent, SA9T, that is well-suited for use in a spacecraft environment. The sorbent is efficiently packaged in pressure-swing regenerable beds that are thermally linked to improve removal efficiency and minimize vehicle thermal loads. Flows are all controlled with a single spool valve. This technology has been baselined for the new Orion spacecraft. However, more data was needed on the operational characteristics of the package in a simulated spacecraft environment. A unit was therefore tested with simulated metabolic loads in a closed chamber at Johnson Space Center during the last third of 2006. Tests were run at a variety of cabin temperatures and with a range of operating conditions varying cycle time, vacuum pressure, air flow rate, and crew activity levels. Results of this testing are presented and potential flight operational strategies discussed.

Monitoring and Managing Cabin Crew Sleep and Fatigue During an Ultra-Long Range Trip.

PubMed

van den Berg, Margo J; Signal, T Leigh; Mulrine, Hannah M; Smith, Alexander A T; Gander, Philippa H; Serfontein, Wynand

2015-08-01

The aims of this study were to monitor cabin crew fatigue, sleep, and performance on an ultra-long range (ULR) trip and to evaluate the appropriateness of applying data collection methods developed for flight crew to cabin crew operations under a fatigue risk management system (FRMS). Prior to, throughout, and following the ULR trip (outbound flight ULR; mean layover duration=52.6 h; inbound flight long range), 55 cabin crew (29 women; mean age 36.5 yr; 25 men; mean age 36.6 yr; one missing data) completed a sleep/duty diary and wore an actigraph. Across each flight, crewmembers rated their fatigue (Samn-Perelli Crew Status Check) and sleepiness (Karolinska Sleepiness Scale) and completed a 5-min Psychomotor Vigilance Task (PVT) at key times. Of crewmembers approached, 73% (N=134) agreed to participate and 41% (N=55) provided data of suitable quality for analysis. In the 24 h before departure, sleep averaged 7.0 h and 40% took a preflight nap. All crewmembers slept in flight (mean total sleep time=3.6 h outbound, 2.9 h inbound). Sleepiness and fatigue were lower, and performance better, on the longer outbound flight than on the inbound flight. Post-trip, crewmembers slept more on day 1 (mean=7.9 h) compared to baseline days, but there was no difference from day 2 onwards. The present study demonstrates that cabin crew fatigue can be managed effectively on a ULR flight and that FRMS data collection is feasible for cabin crew, but operational differences between cabin crew and flight crew need to be considered.

Simultaneously reducing CO2 and particulate exposures via fractional recirculation of vehicle cabin air.

PubMed

Jung, Heejung S; Grady, Michael L; Victoroff, Tristan; Miller, Arthur L

2017-07-01

Prior studies demonstrate that air recirculation can reduce exposure to nanoparticles in vehicle cabins. However when people occupy confined spaces, air recirculation can lead to carbon dioxide (CO 2 ) accumulation which can potentially lead to deleterious effects on cognitive function. This study proposes a fractional air recirculation system for reducing nanoparticle concentration while simultaneously suppressing CO 2 levels in the cabin. Several recirculation scenarios were tested using a custom-programmed HVAC (heat, ventilation, air conditioning) unit that varied the recirculation door angle in the test vehicle. Operating the recirculation system with a standard cabin filter reduced particle concentrations to 1000 particles/cm 3 , although CO 2 levels rose to 3000 ppm. When as little as 25% fresh air was introduced (75% recirculation), CO 2 levels dropped to 1000 ppm, while particle concentrations remained below 5000 particles/cm 3 . We found that nanoparticles were removed selectively during recirculation and demonstrated the trade-off between cabin CO 2 concentration and cabin particle concentration using fractional air recirculation. Data showed significant increases in CO 2 levels during 100% recirculation. For various fan speeds, recirculation fractions of 50-75% maintained lower CO 2 levels in the cabin, while still reducing particulate levels. We recommend fractional recirculation as a simple method to reduce occupants' exposures to particulate matter and CO 2 in vehicles. A design with several fractional recirculation settings could allow air exchange adequate for reducing both particulate and CO 2 exposures. Developing this technology could lead to reductions in airborne nanoparticle exposure, while also mitigating safety risks from CO 2 accumulation.

Simultaneously reducing CO2 and particulate exposures via fractional recirculation of vehicle cabin air

PubMed Central

Jung, Heejung S.; Grady, Michael L.; Victoroff, Tristan; Miller, Arthur L.

2017-01-01

Prior studies demonstrate that air recirculation can reduce exposure to nanoparticles in vehicle cabins. However when people occupy confined spaces, air recirculation can lead to carbon dioxide (CO2) accumulation which can potentially lead to deleterious effects on cognitive function. This study proposes a fractional air recirculation system for reducing nanoparticle concentration while simultaneously suppressing CO2 levels in the cabin. Several recirculation scenarios were tested using a custom-programmed HVAC (heat, ventilation, air conditioning) unit that varied the recirculation door angle in the test vehicle. Operating the recirculation system with a standard cabin filter reduced particle concentrations to 1000 particles/cm3, although CO2 levels rose to 3000 ppm. When as little as 25% fresh air was introduced (75% recirculation), CO2 levels dropped to 1000 ppm, while particle concentrations remained below 5000 particles/cm3. We found that nanoparticles were removed selectively during recirculation and demonstrated the trade-off between cabin CO2 concentration and cabin particle concentration using fractional air recirculation. Data showed significant increases in CO2 levels during 100% recirculation. For various fan speeds, recirculation fractions of 50–75% maintained lower CO2 levels in the cabin, while still reducing particulate levels. We recommend fractional recirculation as a simple method to reduce occupants’ exposures to particulate matter and CO2 in vehicles. A design with several fractional recirculation settings could allow air exchange adequate for reducing both particulate and CO2 exposures. Developing this technology could lead to reductions in airborne nanoparticle exposure, while also mitigating safety risks from CO2 accumulation. PMID:28781568

Design and Testing of a Thermal Storage System for Electric Vehicle Cabin Heating

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Mingyu; WolfeIV, Edward; Craig, Timothy

Without the waste heat available from the engine of a conventional automobile, electric vehicles (EVs) must provide heat to the cabin for climate control using energy stored in the vehicle. In current EV designs, this energy is typically provided by the traction battery. In very cold climatic conditions, the power required to heat the EV cabin can be of a similar magnitude to that required for propulsion of the vehicle. As a result, the driving range of an EV can be reduced very significantly during winter months, which limits consumer acceptance of EVs and results in increased battery costs tomore » achieve a minimum range while ensuring comfort to the EV driver. To minimize the range penalty associated with EV cabin heating, a novel climate control system that includes thermal energy storage has been designed for use in EVs and plug-in hybrid electric vehicles (PHEVs). The system uses the stored latent heat of an advanced phase change material (PCM) to provide cabin heating. The PCM is melted while the EV is connected to the electric grid for charging of the electric battery, and the stored energy is subsequently transferred to the cabin during driving. To minimize thermal losses when the EV is parked for extended periods, the PCM is encased in a high performance insulation system. The electrical PCM-Assisted Thermal Heating System (ePATHS) was designed to provide enough thermal energy to heat the EV s cabin for approximately 46 minutes, covering the entire daily commute of a typical driver in the U.S.« less

Simultaneously reducing CO2 and particulate exposures via fractional recirculation of vehicle cabin air

NASA Astrophysics Data System (ADS)

Jung, Heejung S.; Grady, Michael L.; Victoroff, Tristan; Miller, Arthur L.

2017-07-01

Prior studies demonstrate that air recirculation can reduce exposure to nanoparticles in vehicle cabins. However when people occupy confined spaces, air recirculation can lead to carbon dioxide (CO2) accumulation which can potentially lead to deleterious effects on cognitive function. This study proposes a fractional air recirculation system for reducing nanoparticle concentration while simultaneously suppressing CO2 levels in the cabin. Several recirculation scenarios were tested using a custom-programmed HVAC (heat, ventilation, air conditioning) unit that varied the recirculation door angle in the test vehicle. Operating the recirculation system with a standard cabin filter reduced particle concentrations to 1000 particles/cm3, although CO2 levels rose to 3000 ppm. When as little as 25% fresh air was introduced (75% recirculation), CO2 levels dropped to 1000 ppm, while particle concentrations remained below 5000 particles/cm3. We found that nanoparticles were removed selectively during recirculation and demonstrated the trade-off between cabin CO2 concentration and cabin particle concentration using fractional air recirculation. Data showed significant increases in CO2 levels during 100% recirculation. For various fan speeds, recirculation fractions of 50-75% maintained lower CO2 levels in the cabin, while still reducing particulate levels. We recommend fractional recirculation as a simple method to reduce occupants' exposures to particulate matter and CO2 in vehicles. A design with several fractional recirculation settings could allow air exchange adequate for reducing both particulate and CO2 exposures. Developing this technology could lead to reductions in airborne nanoparticle exposure, while also mitigating safety risks from CO2 accumulation.

Self-assessed occupational health and working environment of female nurses, cabin crew and teachers.

PubMed

Sveinsdóttir, Herdis; Gunnarsdóttir, Hólmfríethur; Friethriksdóttir, Hildur

2007-06-01

The aim of this study was to describe and compare the self-assessed occupational health among female nurses, cabin crew and teachers, in relation to their working environment. Similarities between the three occupations, i.e. predominantly female and service-oriented, render them interesting in comparison with respect to health and working environment. The participants were female Icelandic cabin crew, nurses and elementary school teachers. A questionnaire including items on socio-demographics, working environment (addressing work pace, job security, monotonous work, assistance, physically strenuous work and physical environmental factors) and a symptom list was used for data collection. Factor analyses on the symptom list resulted in five symptom scales: Musculoskeletal, Stress and exhaustion, Common cold, Gastrointestinal and Sound perception scale. A total of 1571 questionnaires were distributed. The response rate was 65.7-69%, depending on occupation. Data were collected in 2002. Cabin crew reported worse gastrointestinal, sound perception and common cold symptoms than nurses and teachers. Cabin crew and teachers reported worse symptoms of stress and exhaustion than nurses (p < 0.05). When compared with teachers and nurses cabin crew reported less job security and more physically strenuous and monotonous work. Nurses were likelier to seek assistance from co-workers or patients as well as to take care of an older relative than teachers and cabin crew. Regression analysis found that within each occupation distress from environmental factors resulted in higher score on all the symptom scales. Nurses experience less stress and exhaustion than teachers and cabin crew. In comparison with one or both of the other occupations nurses are more likely to assist each other with their work, experience job security, reporting physically complex work and take care of older relatives. This should be highlighted as positive aspects of nurses' work praised as displaying responsibility and interconnectedness of nurses'.

Influence of extended incubation time on Human sperm chromatin condensation, sperm DNA strand breaks and their effect on fertilisation rate.

PubMed

Ahmed, I; Abdelateef, S; Laqqan, M; Amor, H; Abdel-Lah, M A; Hammadeh, M E

2018-02-14

The purpose of this study was to determine influence of extended incubation time on sperm chromatin condensation and DNA strand breaks and their effect on fertilisation rate. Forty couples undergoing ICSI therapy were included. Semen was prepared by PureSperm gradient centrifugation and divided into two parts. The first part (G1) was used immediately for ICSI, whereas the second part (G2) was kept in the incubator at 37°C, 5% and 90% Humidity for 5 hr, and thereafter, the capacitated spermatozoa were used for ICSI. The TUNEL test and chromomycin CMA3 were used to evaluate the DNA strand breaks and chromatin condensation respectively. The percentage of condensed chromatin was 73.92 ± 12.70 in the group 1 and 81.13 ± 10.31% in group 2 (p = .001). However, the double-strand breaks were 11.15 ± 8.67% in G.1 and 16.30 ± 11.12% in G.2. (p = .001). Fertilisation rate in the (Group 1) was 62.45% and 69.17% in (Group 2). There was a positive correlation between condensed chromatin and fertilisation rate (r = 0.846, p = .001) and a negative correlation with DNA double-strand breaks (r = -0.802; p = .001). In conclusion, the prolonged sperm incubation (5 hr) leads to a higher chromatin condensation and to a significantly increased number of DNA strands double breaks with no influence on fertilisation rates. © 2018 Blackwell Verlag GmbH.

Integrated CMOS dew point sensors for relative humidity measurement

NASA Astrophysics Data System (ADS)

Savalli, Nicolo; Baglio, Salvatore; Castorina, Salvatore; Sacco, Vincenzo; Tringali, Cristina

2004-07-01

This work deals with the development of integrated relative humidity dew point sensors realized by adopting standard CMOS technology for applications in various fields. The proposed system is composed by a suspended plate that is cooled by exploiting integrated Peltier cells. The cold junctions of the cells have been spread over the plate surface to improve the homogeneity of the temperature distribution over its surface, where cooling will cause the water condensation. The temperature at which water drops occur, named dew point temperature, is a function of the air humidity. Measurement of such dew point temperature and the ambient temperature allows to know the relative humidity. The detection of water drops is achieved by adopting a capacitive sensing strategy realized by interdigited fixed combs, composed by the upper layer of the adopted process. Such a capacitive sensor, together with its conditioning circuit, drives a trigger that stops the cooling of the plate and enables the reading of the dew point temperature. Temperature measurements are achieved by means of suitably integrated thermocouples. The analytical model of the proposed system has been developed and has been used to design a prototype device and to estimate its performances. In such a prototype, the thermoelectric cooler is composed by 56 Peltier cells, made by metal 1/poly 1 junctions. The plate has a square shape with 200 μm side, and it is realized by exploiting the oxide layers. Starting from the ambient temperature a temperature variation of ΔT = 15 K can be reached in 10 ms thus allowing to measure a relative humidity greater than 40%.

Reduction in biomass burning aerosol light absorption upon humidification: roles of inorganically-induced hygroscopicity, particle collapse, and photoacoustic heat and mass transfer

NASA Astrophysics Data System (ADS)

Lewis, K. A.; Arnott, W. P.; Moosmüller, H.; Chakrabarty, R. K.; Carrico, C. M.; Kreidenweis, S. M.; Day, D. E.; Malm, W. C.; Laskin, A.; Jimenez, J. L.; Ulbrich, I. M.; Huffman, J. A.; Onasch, T. B.; Trimborn, A.; Liu, L.; Mishchenko, M. I.

2009-07-01

Smoke particle emissions from the combustion of biomass fuels typical for the western and southeastern United States were studied and compared under high humidity and ambient conditions in the laboratory. The fuels used are Montana ponderosa pine (Pinus ponderosa), southern California chamise (Adenostoma fasciculatum), and Florida saw palmetto (Serenoa repens). Information on the non-refractory chemical composition of biomass burning aerosol from each fuel was obtained with an aerosol mass spectrometer and through estimation of the black carbon concentration from light absorption measurements at 870 nm. Changes in the optical and physical particle properties under high humidity conditions were observed for hygroscopic smoke particles containing substantial inorganic mass fractions that were emitted from combustion of chamise and palmetto fuels. Light scattering cross sections increased under high humidity for these particles, consistent with the hygroscopic growth measured for 100 nm particles in HTDMA measurements. Photoacoustic measurements of aerosol light absorption coefficients reveal a 20% reduction with increasing relative humidity, contrary to the expectation of light absorption enhancement by the liquid coating taken up by hygroscopic particles. This reduction is hypothesized to arise from two mechanisms: 1. Shielding of inner monomers after particle consolidation or collapse with water uptake; 2. The contribution of mass transfer through evaporation and condensation at high relative humidity to the usual heat transfer pathway for energy release by laser-heated particles in the photoacoustic measurement of aerosol light absorption. The mass transfer contribution is used to evaluate the fraction of aerosol surface covered with liquid water solution as a function of RH.

The Sensitivity of West African Squall Line Water Budgets to Land Cover

NASA Technical Reports Server (NTRS)

Mohr, Karen I.; Baker, R. David; Tao, Wei-Kuo; Famiglietti, James S.; Starr, David OC. (Technical Monitor)

2001-01-01

This study used a two-dimensional coupled land/atmosphere (cloud-resolving) model to investigate the influence of land cover on the water budgets of squall lines in the Sahel. Study simulations used the same initial sounding and one of three different land covers, a sparsely vegetated semi-desert, a grassy savanna, and a dense evergreen broadleaf forest. All simulations began at midnight and ran for 24 hours to capture a full diurnal cycle. In the morning, the latent heat flux, boundary layer mixing ratio, and moist static energy in the boundary layer exhibited notable variations among the three land covers. The broadleaf forest had the highest latent heat flux, the shallowest, moistest, slowest growing boundary layer, and significantly more moist static energy per unit area than the savanna and semi-desert. Although all simulations produced squall lines by early afternoon, the broadleaf forest had the most intense, longest-lived squall lines with 29% more rainfall than the savanna and 37% more than the semi-desert. The sensitivity of the results to vegetation density, initial sounding humidity, and grid resolution was also assessed. There were greater differences in rainfall among land cover types than among simulations of the same land cover with varying amounts of vegetation. Small changes in humidity were equivalent in effect to large changes in land cover, producing large changes in the condensate and rainfall. Decreasing the humidity had a greater effect on rainfall volume than increasing the humidity. Reducing the grid resolution from 1.5 km to 0.5 km decreased the temperature and humidity of the cold pools and increased the rain volume.

Mesoporous Silicate Materials in Sensing

PubMed Central

Melde, Brian J.; Johnson, Brandy J.; Charles, Paul T.

2008-01-01

Mesoporous silicas, especially those exhibiting ordered pore systems and uniform pore diameters, have shown great potential for sensing applications in recent years. Morphological control grants them versatility in the method of deployment whether as bulk powders, monoliths, thin films, or embedded in coatings. High surface areas and pore sizes greater than 2 nm make them effective as adsorbent coatings for humidity sensors. The pore networks also provide the potential for immobilization of enzymes within the materials. Functionalization of materials by silane grafting or through co-condensation of silicate precursors can be used to provide mesoporous materials with a variety of fluorescent probes as well as surface properties that aid in selective detection of specific analytes. This review will illustrate how mesoporous silicas have been applied to sensing changes in relative humidity, changes in pH, metal cations, toxic industrial compounds, volatile organic compounds, small molecules and ions, nitroenergetic compounds, and biologically relevant molecules. PMID:27873810

On the Utility (or Futility) of Using Stable Water Isotopes to Constrain the Bulk Properties of Tropical Convection

NASA Astrophysics Data System (ADS)

Duan, Suqin Q.; Wright, Jonathon S.; Romps, David M.

2018-02-01

Atmospheric water-vapor isotopes have been proposed as a potentially powerful constraint on convection, which plays a critical role in Earth's present and future climate. It is shown here, however, that the mean tropical profile of HDO in the free troposphere does not usefully constrain the mean convective entrainment rate or precipitation efficiency. This is demonstrated using a single-column analytical model of atmospheric water isotopes. The model has three parameters: the entrainment rate, the precipitation efficiency, and the distance that evaporating condensates fall. At a given relative humidity, the possible range of HDO is small: its range is comparable to both the measurement uncertainty in the mean tropical profile and the structural uncertainty of a single-column model. Therefore, the mean tropical HDO profile is unlikely to add information about convective processes in a bulk-plume framework that cannot already be learned from relative humidity alone.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boreyko, Jonathan B.; Srijanto, Bernadeta R.; Nguyen, Trung Dac

Water suspended on chilled superhydrophobic surfaces exhibits delayed freezing; however, the interdrop growth of frost through subcooled condensate forming on the surface seems unavoidable in humid environments. It is therefore of great practical importance to determine whether facile defrosting is possible on superhydrophobic surfaces. Here in this paper, we report that nanostructured superhydrophobic surfaces promote the growth of frost in a suspended Cassie state, enabling its dynamic removal upon partial melting at low tilt angles (<15°). The dynamic removal of the melting frost occurred in two stages: spontaneous dewetting followed by gravitational mobilization. This dynamic defrosting phenomenon is driven bymore » the low contact angle hysteresis of the defrosted meltwater relative to frost on microstructured superhydrophobic surfaces, which forms in the impaled Wenzel state. Dynamic defrosting on nanostructured superhydrophobic surfaces minimizes the time, heat, and gravitational energy required to remove frost from the surface, and is of interest for a variety of systems in cold and humid environments.« less

Use of Normothermic Default Humidifier Settings Causes Excessive Humidification of Respiratory Gases During Therapeutic Hypothermia.

PubMed

Tanaka, Shoichiro; Iwata, Sachiko; Kinoshita, Masahiro; Tsuda, Kennosuke; Sakai, Sayaka; Saikusa, Mamoru; Shindo, Ryota; Harada, Eimei; Okada, Junichiro; Hisano, Tadashi; Kanda, Hiroshi; Maeno, Yasuki; Araki, Yuko; Ushijima, Kazuo; Sakamoto, Teruo; Yamashita, Yushiro; Iwata, Osuke

2016-12-01

Adult patients frequently suffer from serious respiratory complications during therapeutic hypothermia. During therapeutic hypothermia, respiratory gases are humidified close to saturated vapor at 37°C (44 mg/L) despite that saturated vapor reduces considerably depending on temperature reduction. Condensation may cause serious adverse events, such as bronchial edema, mucosal dysfunction, and ventilator-associated pneumonia during cooling. To determine clinical variables associated with inadequate humidification of respiratory gases during cooling, humidity of inspiratory gases was measured in 42 cumulative newborn infants who underwent therapeutic hypothermia. Three humidifier settings of 37-default (chamber outlet, 37°C; distal circuit, 40°C), 33.5-theoretical (chamber outlet, 33.5°C; distal circuit, 36.5°C), and 33.5-adjusted (optimized setting to achieve 36.6 mg/L using feedback from a hygrometer) were tested to identify independent variables of excessively high humidity >40.7 mg/L and low humidity <32.9 mg/L. The mean (SD) humidity at the Y-piece was 39.2 (5.2), 33.3 (4.1), and 36.7 (1.2) mg/L for 37-default, 33.5-theoretical, and 33.5-adjusted, respectively. The incidence of excessive high humidity was 10.3% (37-default, 31.0%; 33.5-theoretical, 0.0%; 33.5-adjusted, 0.0%), which was positively associated with the use of a counter-flow humidifier (p < 0.001), 37-default (compared with 33.5-theoretical and 33.5-adjusted, both p < 0.001) and higher fraction of inspired oxygen (p = 0.003). The incidence of excessively low humidity was 17.5% (37-default, 7.1%; 33.5-theoretical, 45.2%; 33.5-adjusted, 0.0%), which was positively associated with the use of a pass-over humidifier and 33.5-theoretical (both p < 0.001). All patients who used a counter-flow humidifier achieved the target gas humidity at the Y-piece (36.6 ± 0.5 mg/L) required for 33.5-adjusted with 33.5-theoretical. During cooling, 37-default is associated with excessively high humidity, whereas 33.5-theoretical leads to excessively low humidity. Future studies are needed to assess whether a new regimen with optimized Y-piece temperature and humidity control reduces serious respiratory adverse events during cooling.

[Effect of early intervention with heparin on function of coagulopathy, liver and kidney in rats with exertional heatstroke under the ambient air of high temperature and low humidity].

PubMed

Yu, Yang; Wei, Yuying; Zhang, Xiangrong; Li, Xinyu

2018-03-01

To explore the effects of early intervention with heparin on function of coagulopathy, liver and kidney as well as the prognosis in rats with exertional heatstroke (EHS) under the ambient air of high temperature and low humidity. 108 healthy SPF male Sprague-Dawley (SD) rats were randomly divided into normal temperature control group, EHS + normal saline (NS) group and EHS + heparin group. Of which 54 rats were collected for survival analysis (18 rats in each group), the weight change and 8-hour survival rate were observed, and Kaplan-Meier survival curves were drawn. Other 54 rats were collected for intervention experiment, the rats in each group were subdivided into 0, 1, 2 hours subgroups according to the time points of intervention with heparin after model reproduction, with 6 rats in each subgroup. The rats were placed in an artificial experiment cabin with northwest special environment, and the temperature and the relative humidity were (25.0±1.0) centigrade and (35±5)%, respectively, in normal temperature control group, and the rats were not treated in the cabin. The rats in EHS + NS group and EHS + heparin group kept running in the cabin which temperature and relative humidity were set at (43.0±0.5) centigrade and (35±5)% until the anus temperature of rats reached 43.0 centigrade, and then the rats were placed in room temperature. The rats were injected with 1 mL/kg NS or 250 U/kg heparin sodium injection through their caudal veins at 0, 1, and 2 hours, respectively, and then the blood was collected after 1.5 hours to determine the biochemical parameters including coagulation, liver and kidney as well as platelet count (PLT). (1) The weight loss of EHS + NS group and EHS + heparin group was more significant than that of normal temperature control group (g: 8.28±1.41, 8.39±1.38 vs. 2.06±1.06, both P < 0.05), but there was no significant difference between EHS + NS group and EHS + heparin group. (2) As the time went on after modeling, serum creatinine (SCr), blood urea nitrogen (BUN), alanine aminotransferase (ALT), aspartate aminotransferase (AST), creatine kinase (CK), activated partial thromboplastin time (APTT), and D-dimer of EHS rats showed a tendency of increasing, but fibrinogen (FBG), antithrombin III (AT III) and PLT were decreased gradually, which were obviously abnormal as compared with those at corresponding time point of the normal temperature control group. Heparin intervention 0 hour after modeling could improve the function of liver and kidney, FBG, D-dimer, AT III and PLT, but APTT was prolonged further. The SCr, BUN, ALT, AST and CK in EHS 2 hours + heparin group were still better than EHS + NS group [SCr (μmol/L): 93.33±7.69 vs. 110.50±13.56, BUN (mmol/L): 20.55±1.35 vs. 24.88±2.41, ALT (U/L): 322.17±36.36 vs. 492.33±64.19, AST (U/L): 1 252.33±240.86 vs. 2 725.67±461.17, CK (U/L): 1 4628.67±2 784.68 vs. 2 6843.00±2 637.16, all P < 0.01], APTT was significantly prolonged (s: 51.83±6.11 vs. 33.83±4.31, P < 0.01), and AT III and PLT were significantly increased [AT III: (78.03±9.15)% vs. (64.28±12.55)%, PLT (×10 9 /L): 457.67±32.33 vs. 415.83±26.45, both P < 0.05], however, there was no obvious influence on FBG or D-dimer. (3) The rats in normal temperature control group were all survived within 8 hours, and all dead in EHS + NS group. The survival rate of rats given heparin intervention at 0, 1, 2 hours after successfully modeling was 50.0%, 33.3% and 0%, respectively. Kaplan-Meier survival curve analysis showed that 8-hour cumulative survival rate in EHS 0 hour, 1 hour + heparin groups was higher than that in EHS 0 hour, 1 hour + NS groups (χ 1 2 = 7.930, P 1 = 0.005; χ 2 2 = 4.408, P 2 = 0.036), however, there was no significant difference between EHS 2 hours + heparin group and EHS 2 hours + NS group (χ 2 = 2.660, P = 0.103). Early heparin intervention can improve the coagulation function and organ function of EHS rats, while improving the survival rate of rats, indicating the earlier intervention of heparin, the better prognosis of rats is.

Modeling Gas-Particle Partitioning of SOA: Effects of Aerosol Physical State and RH

NASA Astrophysics Data System (ADS)

Zuend, A.; Seinfeld, J.

2011-12-01

Aged tropospheric aerosol particles contain mixtures of inorganic salts, acids, water, and a large variety of organic compounds. In liquid aerosol particles non-ideal mixing of all species determines whether the condensed phase undergoes liquid-liquid phase separation or whether it is stable in a single mixed phase, and whether it contains solid salts in equilibrium with their saturated solution. The extended thermodynamic model AIOMFAC is able to predict such phase states by representing the variety of organic components using functional groups within a group-contribution concept. The number and composition of different condensed phases impacts the diversity of reaction media for multiphase chemistry and the gas-particle partitioning of semivolatile species. Recent studies show that under certain conditions biogenic and other organic-rich particles can be present in a highly viscous, semisolid or amorphous solid physical state, with consequences regarding reaction kinetics and mass transfer limitations. We present results of new gas-particle partitioning computations for aerosol chamber data using a model based on AIOMFAC activity coefficients and state-of-the-art vapor pressure estimation methods. Different environmental conditions in terms of temperature, relative humidity (RH), salt content, amount of precursor VOCs, and physical state of the particles are considered. We show how modifications of absorptive and adsorptive gas-particle mass transfer affects the total aerosol mass in the calculations and how the results of these modeling approaches compare to data of aerosol chamber experiments, such as alpha-pinene oxidation SOA. For a condensed phase in a mixed liquid state containing ammonium sulfate, the model predicts liquid-liquid phase separation up to high RH in case of, on average, moderately hydrophilic organic compounds, such as first generation oxidation products of alpha-pinene. The computations also reveal that treating liquid phases as ideal mixtures substantially overestimates the SOA mass, especially at high relative humidity.

The Relationship between Relative Humidity and the Dewpoint Temperature in Moist Air: A Simple Conversion and Applications.

NASA Astrophysics Data System (ADS)

Lawrence, Mark G.

2005-02-01

The relative humidity (RH) and the dewpoint temperature (td) are two widely used indicators of the amount of moisture in air. The exact conversion from RH to td, as well as highly accurate approximations, are too complex to be done easily without the help of a calculator or computer. However, there is a very simple rule of thumb that can be very useful for approximating the conversion for moist air (RH > 50%) which does not appear to be widely known by the meteorological community: td decreases by about 1°C for every 5% decrease in RH (starting at td = t, the dry bulb temperature, when RH = 100%). This article examines the mathematical basis and accuracy of this and other relationships between the dewpoint and relative humidity. Several useful applications of the simple conversion are presented, in particular the computation of the cumulus cloud-base level (or lifting condensation level) as zLCL (20 + t/5) (100 - RH), where zLCL is in meters when t is in degrees Celcius and RH in percent. Finally, a historical perspective is given with anecdotes about some of the early work in this field.

Passive anti-frosting surfaces using microscopic ice arrays

NASA Astrophysics Data System (ADS)

Ahmadi, Farzad; Nath, Saurabh; Iliff, Grady; Boreyko, Jonathan

2017-11-01

Despite exceptional advances in surface chemistry and micro/nanofabrication, no engineered surface has been able to passively suppress the in-plane growth of frost occurring in humid, subfreezing environments. Motivated by this, and inspired by the fact that ice itself can evaporate nearby liquid water droplets, we present a passive anti-frosting surface in which the majority of the surface remains dry indefinitely. We fabricated an aluminum surface exhibiting an array of small metallic fins, where a wicking micro-groove was laser-cut along the top of each fin to produce elevated water ``stripes'' that freeze into ice. As the saturation vapor pressure of ice is less than that of supercooled liquid water, the ice stripes serve as overlapping humidity sinks that siphon all nearby moisture from the air and prevent condensation and frost from forming anywhere else on the surface. Our experimental results show that regions between stripes remain dry even after 24 hours of operation under humid and supercooled conditions. We believe that the presented anti-frosting technology has the potential to help solve the world's multi-billion dollar frosting problem that adversely affects transportation, power generation, and HVAC systems.

Effectiveness of Humidification with Heat and Moisture Exchanger-booster in Tracheostomized Patients

PubMed Central

Gonzalez, Isabel; Jimenez, Pilar; Valdivia, Jorge; Esquinas, Antonio

2017-01-01

Background: The two most commonly used types of humidifiers are heated humidifiers and heat and moisture exchange humidifiers. Heated humidifiers provide adequate temperature and humidity without affecting the respiratory pattern, but overdose can cause high temperatures and humidity resulting in condensation, which increases the risk of bacteria in the circuit. These devices are expensive. Heat and moisture exchanger filter is a new concept of humidification, increasing the moisture content in inspired gases. Aims: This study aims to determine the effectiveness of the heat and moisture exchanger (HME)-Booster system to humidify inspired air in patients under mechanical ventilation. Materials and Methods: We evaluated the humidification provided by 10 HME-Booster for tracheostomized patients under mechanical ventilation using Servo I respirators, belonging to the Maquet company and Evita 4. Results: There was an increase in the inspired air humidity after 1 h with the humidifier. Conclusion: The HME-Booster combines the advantages of heat and moisture exchange minimizing the negatives. It increases the amount of moisture in inspired gas in mechanically ventilated tracheostomized patients. It is easy and safe to use. The type of ventilator used has no influence on the result. PMID:28904484

Numerical modelling of powder caking at REV scale by using DEM

NASA Astrophysics Data System (ADS)

Guessasma, Mohamed; Silva Tavares, Homayra; Afrassiabian, Zahra; Saleh, Khashayar

2017-06-01

This work deals with numerical simulation of powder caking process caused by capillary condensation phenomenon. Caking consists in unwanted agglomeration of powder particles. This process is often irreversible and not easy to predict. To reproduce mechanism involved by caking phenomenon we have used the Discrete Elements Method (DEM). In the present work, we mainly focus on the role of capillary condensation and subsequent liquid bridge formation within a granular medium exposed to fluctuations of ambient relative humidity. Such bridges cause an attractive force between particles, leading to the formation of a cake with intrinsic physicochemical and mechanical properties. By considering a Representative Elementary Volume (REV), the DEM is then performed by means of a MULTICOR-3D software tacking into account the properties of the cake (degree of saturation) in order to establish relationships between the microscopic parameters and the macroscopic behaviour (tensile strength).

Participation in the Mars Data Analysis Program: Analysis of cloud forms in Viking and Mariner 9 images

NASA Technical Reports Server (NTRS)

Gierasch, P.; Kahn, R. A.

1985-01-01

The first systematic account of the climate of Mars, based upon observations was produced. Cloud data were used to determine spatially and temporally varying near-surface wind direction, relative wind speed, static stability, and humidity conditions on a global scale. Existing models of meteorological processes were critically reexamined in light of the data, and more stringent constraints were set on global processes. Several discoveries were made, including the large extent and seasonal variability of the Mars equatorial Hadley cell, the failure of high latitude winds to reverse direction in early northern spring, the change in meridional wind component in southern midautum, and the almost constant cloud cover in the northern hemisphere, during spring and summer primarily by condensate clouds and in fall and winter by condensates and dust. The implications of these observations are discussed.

Wildfires in Eastern U.S.

NASA Technical Reports Server (NTRS)

2002-01-01

Drought conditions have plagued the Appalachian Mountains in October and November, and low relative humidity combined with dry leaves on the ground has created extreme fire danger in many eastern states. This true-color MODIS image made from data collected on November 13, 2001, shows smoke from numerous fires (indicated in red), predominantly in southern West Virginia (image center), Kentucky (to the southwest), and Tennessee (south). The fires, at least some of which are likely the result of arson, have burned thousands of acres throughout the region. Unfortunately for those people fighting the fires, the fire danger is likely to remain high, with no significant rain expected in the near term. South of Lake Erie, the southernmost of the Great Lakes, numerous aircraft contrails crisscross Ohio. Water vapor emitted with engine exhaust condenses in the cold, dry air at high altitudes, leaving behind a trail of condensation--a contrail. Image courtesy Jacques Descloitres, MODIS Land Rapid Response Team at NASA GSFC

Conditioning of inspired air by a hygroscopic condenser humidifier.

PubMed

Primiano, F P; Moranz, M E; Montague, F W; Miller, R B; Sachs, D P

1984-08-01

The heat and water content of inspired air is critical to the pulmonary viability of patients with artificial airways. By continuously measuring gas conditions in the ventilator circuits of 6 adult ICU patients, we studied the heat and water reclaimed from expired air by a hygroscopic condenser humidifier (HCH) in the circuit. Temperature, partial pressure of water vapor (PH2O) and relative humidity (RH) were determined at the tracheal outlet of the endotracheal tube. The HCH was 63% efficient; the end-inspiratory gas delivered to the patients averaged 30.9 degrees C with a PH2O of 32.5 mm Hg and an RH of 97.3% or, equivalently, an RH of 69.2% referenced to 37 degrees C. These values are lower than those reported in the literature for gas in the trachea during nose breathing of ambient air, but greater than the values reported for mouth breathing of ambient air.

Transport of expiratory droplets in an aircraft cabin.

PubMed

Gupta, Jitendra K; Lin, Chao-Hsin; Chen, Qingyan

2011-02-01

The droplets exhaled by an index patient with infectious disease such as influenza or tuberculosis may be the carriers of contagious agents. Indoor environments such as the airliner cabins may be susceptible to infection from such airborne contagious agents. The present investigation computed the transport of the droplets exhaled by the index patient seated in the middle of a seven-row, twin-aisle, fully occupied cabin using the CFD simulations. The droplets exhaled were from a single cough, a single breath, and a 15-s talk of the index patient. The expiratory droplets were tracked by using Lagrangian method, and their evaporation was modeled. It was found that the bulk airflow pattern in the cabin played the most important role on the droplet transport. The droplets were contained in the row before, at, and after the index patient within 30 s and dispersed uniformly to all the seven rows in 4 minutes. The total airborne droplet fraction reduced to 48, 32, 20, and 12% after they entered the cabin for 1, 2, 3, and 4 min, respectively, because of the ventilation from the environmental control system. It is critical to predict the risk of airborne infection to take appropriate measures to control and mitigate the risk. Most of the studies in past either assume a homogenous distribution of contaminants or use steady-state conditions. The present study instead provides information on the transient movement of the droplets exhaled by an index passenger in an aircraft cabin. These droplets may contain active contagious agents and can be potent enough to cause infection. The findings can be used by medical professionals to estimate the spatial and temporal distribution of risk of infection to various passengers in the cabin. © 2010 John Wiley & Sons A/S.

A Cabin Air Separator for EVA Oxygen

NASA Technical Reports Server (NTRS)

Graf, John C.

2011-01-01

Presently, the Extra-Vehicular Activities (EVAs) conducted from the Quest Joint Airlock on the International Space Station use high pressure, high purity oxygen that is delivered to the Space Station by the Space Shuttle. When the Space Shuttle retires, a new method of delivering high pressure, high purity oxygen to the High Pressure Gas Tanks (HPGTs) is needed. One method is to use a cabin air separator to sweep oxygen from the cabin air, generate a low pressure/high purity oxygen stream, and compress the oxygen with a multistage mechanical compressor. A main advantage to this type of system is that the existing low pressure oxygen supply infrastructure can be used as the source of cabin oxygen. ISS has two water electrolysis systems that deliver low pressure oxygen to the cabin, as well as chlorate candles and compressed gas tanks on cargo vehicles. Each of these systems can feed low pressure oxygen into the cabin, and any low pressure oxygen source can be used as an on-board source of oxygen. Three different oxygen separator systems were evaluated, and a two stage Pressure Swing Adsorption system was selected for reasons of technical maturity. Two different compressor designs were subjected to long term testing, and the compressor with better life performance and more favorable oxygen safety characteristics was selected. These technologies have been used as the basis of a design for a flight system located in Equipment Lock, and taken to Preliminary Design Review level of maturity. This paper describes the Cabin Air Separator for EVA Oxygen (CASEO) concept, describes the separator and compressor technology trades, highlights key technology risks, and describes the flight hardware concept as presented at Preliminary Design Review (PDR)

Extravehicular Crewman Work System (ECWS) study program: Prebreathe elimination study

NASA Technical Reports Server (NTRS)

Wilde, R. L.

1981-01-01

The study examined impacts of changing Orbiter cabin pressure and EMU EVA pressure to eliminate pure O2 prebreathing prior to EVA. The investigation defines circumscribing physiological boundaries and identifies changes required within Orbiter to reduce cabin pressure. The study also identifies payload impacts, payload flight assignment constraints, and impacts upon EMU resulting from raising EVA pressure. The study presents the trade-off which optimizes the choice of reduced cabin pressure and increased EVA pressure.

Effect of commercial airline travel on oxygen saturation in athletes.

PubMed

Geertsema, C; Williams, A B; Dzendrowskyj, P; Hanna, C

2008-11-01

Aircraft cabins are pressurised to maximum effective altitudes of 2440 metres, resulting in significant decline in oxygen saturation in crew and passengers. This effect has not been studied in athletes. To investigate the degree of decline in oxygen saturation in athletes during long-haul flights. A prospective cross-sectional study. National-level athletes were recruited. Oxygen saturation and heart rate were measured with a pulse oximeter at sea level before departure, at 3 and 7 hours into the flight, and again after arrival at sea level. Aircraft cabin pressure and altitude, cabin fraction of inspired oxygen and true altitude were also recorded. 45 athletes and 18 healthy staff aged between 17 and 70 years were studied on 10 long-haul flights. Oxygen saturation levels declined significantly after 3 hours and 7 hours (3-4%), compared with sea level values. There was an associated drop in cabin pressure and fraction of inspired oxygen, and an increase in cabin altitude. Oxygen saturation declines significantly in athletes during long-haul commercial flights, in response to reduced cabin pressure. This may be relevant for altitude acclimatization planning by athletes, as the time spent on the plane should be considered time already spent at altitude, with associated physiological changes. For flights of 10-13 hours in duration, it will be difficult to arrive on the day of competition to avoid the influence of these changes, as is often suggested by coaches.

Laboratory and on-road evaluations of cabin air filters using number and surface area concentration monitors.

PubMed

Qi, Chaolong; Stanley, Nick; Pui, David Y H; Kuehn, Thomas H

2008-06-01

An automotive cabin air filter's effectiveness for removing airborne particles was determined both in a laboratory wind tunnel and in vehicle on-road tests. The most penetrating particle size for the test filter was approximately 350 nm, where the filtration efficiency was 22.9 and 17.4% at medium and high fan speeds, respectively. The filtration efficiency increased for smaller particles and was 43.9% for 100 nm and 72.0% for 20 nm particles at a medium fan speed. We determined the reduction in passenger exposure to particles while driving in freeway traffic caused by a vehicle ventilation system with a cabin air filter installed. Both particle number and surface area concentration measurements were made inside the cabin and in the surrounding air. At medium fan speed, the number and surface area concentration-based exposure reductions were 65.6 +/- 6.0% and 60.6 +/- 9.4%, respectively. To distinguish the exposure reduction contribution from the filter alone and the remainder of the ventilation system, we also performed tests with and without the filter in place using the surface area monitors. The ventilation system operating in the recirculation mode with the cabin air filter installed provided the maximum protection, reducing the cabin particle concentration exponentially over time and usually taking only 3 min to reach 10 microm2/cm3 (a typical office air condition) under medium fan speed.

Loss of cabin pressurization in U.S. Naval aircraft: 1969-90.

PubMed

Bason, R; Yacavone, D W

1992-05-01

During the 22-year period from 1 January 1969 to 31 December 1990, there were 205 reported cases of loss of cabin pressure in US Naval aircraft; 21 were crew-initiated and 184 were deemed accidental. The ambient altitudes varied from 10,000 ft (3048 m) to 40,000 ft. (12192 m). The most common reason for crew-initiated decompression was to clear smoke and fumes from the cockpit/cabin (95%). The most common cause for accidental loss of cabin pressure was mechanical (73.37%), with aircraft structural damage accounting for the remaining 26.63%. Serious physiological problems included 1 pneumothorax, 11 cases of Type I decompression sickness, 23 cases of mild to moderate hypoxia with no loss of consciousness, 18 cases of hypoxia with loss of consciousness, and 3 lost aircraft with 4 fatalities due to incapacitation by hypoxia. In addition, 12 ejections were attributed to loss of cockpit pressure. Nine of the ejections were deliberate and three were accidental, caused by wind blast activation of the face curtain. Three aviators lost their lives following ejection and seven aircraft were lost. While the incidence of loss of cabin pressure in Naval aircraft appears low, it none-the-less presents a definite risk to the aircrew. Lectures on the loss of cabin/cockpit pressurization should continue during indoctrination and refresher physiology training.

Tick-Borne Relapsing Fever Outbreak Among a High School Football Team at an Outdoor Education Camping Trip, Arizona, 2014.

PubMed

Jones, Jefferson M; Hranac, Carter R; Schumacher, Mare; Horn, Kim; Lee, Darlene M; Terriquez, Joel; Engelthaler, David M; Peoples, Marie; Corrigan, Jennifer; Replogle, Adam; Souders, Nina; Komatsu, Kenneth K; Nieto, Nathan C

2016-09-07

During August 2014, five high school students who had attended an outdoor education camp were hospitalized with a febrile illness, prompting further investigation. Ten total cases of tick-borne relapsing fever (TBRF) were identified-six cases confirmed by culture or visualization of spirochetes on blood smear and four probable cases with compatible symptoms (attack rate: 23%). All patients had slept in the campsite's only cabin. Before the camp, a professional pest control company had rodent proofed the cabin, but no acaricides had been applied. Cabin inspection after the camp found rodents and Ornithodoros ticks, the vector of TBRF. Blood samples from a chipmunk trapped near the cabin and from patients contained Borrelia hermsii with identical gene sequences (100% over 630 base pairs). Health departments in TBRF endemic areas should consider educating cabin owners and pest control companies to apply acaricides during or following rodent proofing, because ticks that lack rodents for a blood meal might feed on humans. © The American Society of Tropical Medicine and Hygiene.

Orion Emergency Mask Approach

NASA Technical Reports Server (NTRS)

Tuan, George C.; Graf, John C.

2008-01-01

Emergency mask approach on Orion poses a challenge to the traditional Shuttle or Station approaches. Currently, in the case of a fire or toxic spill event, the crew utilizes open loop oxygen masks that provide the crew with oxygen to breath, but also dumps the exhaled oxygen into the cabin. For Orion, with a small cabin volume, the extra oxygen will exceed the flammability limit within a short period of time, unless a nitrogen purge is also provided. Another approach to a fire or toxic spill event is the use of a filtering emergency masks. These masks utilize some form of chemical beds to scrub the air clean of toxic providing the crew safe breathing air for a period without elevating the oxygen level in the cabin. Using the masks and a form of smoke-eater filter, it may be possible to clean the cabin completely or to a level for safe transition to a space suit to perform a cabin purge. Issues with filters in the past have been the reaction temperature and high breathing resistance. Development in a new form of chemical filters has shown promise to make the filtering approach feasible.

Orion Emergency Mask Approach

NASA Technical Reports Server (NTRS)

Tuan, George C.; Graf, John C.

2009-01-01

Emergency mask approach on Orion poses a challenge to the traditional Shuttle or Station approaches. Currently, in the case of a fire or toxic spill event, the crew utilizes open loop oxygen masks that provide the crew with oxygen to breath, but also dumps the exhaled oxygen into the cabin. For Orion, with a small cabin volume, the extra oxygen will exceed the flammability limit within a short period of time, unless a nitrogen purge is also provided. Another approach to a fire or toxic spill event is the use of a filtering emergency masks. These masks utilize some form of chemical beds to scrub the air clean of toxic providing the crew safe breathing air for a period without elevating the oxygen level in the cabin. Using the masks and a form of smoke-eater filter, it may be possible to clean the cabin completely or to a level for safe transition to a space suit to perform a cabin purge. Issues with filters in the past have been the reaction time, breakthroughs, and high breathing resistance. Development in a new form of chemical filters has shown promise to make the filtering approach feasible.

Numerical simulation study on air quality in aircraft cabins.

PubMed

Zhao, Yingjie; Dai, Bingrong; Yu, Qi; Si, Haiqing; Yu, Gang

2017-06-01

Air pollution is one of the main factors that affect the air quality in aircraft cabins, and the use of different air supply modes could influence the distribution of air pollutants in cabins. Based on the traditional ceiling air supply mode used on the B737NG, this study investigated another 3 different kinds of air supply modes for comparison: luggage rack air supply mode, joint mode combining ceiling and luggage rack air supply, and joint mode combining ceiling and individual air supply. Under the above 4 air supply modes, the air velocity, temperature and distribution of air pollutants in a cabin full of passengers were studied using computational fluid dynamics (CFD), and carbon dioxide (CO 2 ) and formaldehyde were selected as 2 kinds of representative air pollutants. The simulation results show that the joint mode combining ceiling and individual air supply can create a more uniform distribution of air velocity and temperature, has a better effect on the removal of CO 2 and formaldehyde, and can provide better air quality in cabins than the other 3 modes. Copyright © 2016. Published by Elsevier B.V.

PTR-MS assessment of photocatalytic and sorption-based purification of recirculated cabin air during simulated 7-h flights with high passenger density.

PubMed

Wisthaler, Armin; Strøm-Tejsen, Peter; Fang, Lei; Arnaud, Timothy J; Hansel, Armin; Märk, Tilmann D; Wyon, David P

2007-01-01

Four different air purification conditions were established in a simulated 3-row 21-seat section of an aircraft cabin: no air purifier; a photocatalytic oxidation unit with an adsorptive prefilter; a second photocatalytic unit with an adsorptive prefilter; and a two-stage sorption-based air filter (gas-phase absorption and adsorption). The air purifiers placed in the cabin air recirculation system were commercial prototypes developed for use in aircraft cabin systems. The four conditions were established in balanced order on 4 successive days of each of 4 successive weeks during simulated 7-h flights with 17 occupants. Proton-transfer reaction mass spectrometry was used to assess organic gas-phase pollutants and the performance of each air purifier. The concentration of most organic pollutants present in aircraft cabin air was efficiently reduced by all three units. The photocatalytic units were found to incompletely oxidize ethanol released by the wet wipes commonly supplied with airline mealsto produce unacceptably high levels of acetaldehyde and formaldehyde.

Simple Systems for Detecting Spacecraft Meteoroid Punctures

NASA Technical Reports Server (NTRS)

Hall, Stephen B.

2004-01-01

A report describes proposed systems to be installed in spacecraft to detect punctures by impinging meteoroids or debris. Relative to other systems that have been used for this purpose, the proposed systems would be simpler and more adaptable, and would demand less of astronauts attention and of spacecraft power and computing resources. The proposed systems would include a thin, hollow, hermetically sealed panel containing an inert fluid at a pressure above the spacecraft cabin pressure. A transducer would monitor the pressure in the panel. It is assumed that an impinging object that punctures the cabin at the location of the panel would also puncture the panel. Because the volume of the panel would be much smaller than that of the cabin, the panel would lose its elevated pressure much faster than the cabin would lose its lower pressure. The transducer would convert the rapid pressure drop to an electrical signal that could trigger an alarm. Hence, the system would provide an immediate indication of the approximate location of a small impact leak, possibly in time to take corrective action before a large loss of cabin pressure could occur.

Aviation occupant survival factors: an empirical study of the SQ006 accident.

PubMed

Chang, Yu-Hern; Yang, Hui-Hua

2010-03-01

We present an empirical study of Singapore Airline (SIA) flight SQ006 to illustrate the critical factors that influence airplane occupant survivability. The Fuzzy Delphi Method was used to identify and rank the survival factors that may reduce injury and fatality in potentially survivable accidents. This is the first attempt by a group from both the public and private sectors in Taiwan to focus on cabin-safety issues related to survival factors. We designed a comprehensive survey based on our discussions with aviation safety experts. We next designed an array of important cabin-safety dimensions and then investigated and selected the critical survival factors for each dimension. Our findings reveal important cabin safety and survivability information that should provide a valuable reference for developing and evaluating aviation safety programs. We also believe that the results will be practical for designing cabin-safety education material for air travelers. Finally, the major contribution of this research is that it has identified 47 critical factors that influence accident survivability; therefore, it may encourage improvements that will promote more successful cabin-safety management. Copyright 2009 Elsevier Ltd. All rights reserved.

Study of Hygrothermal Processes in External Walls with Internal Insulation

NASA Astrophysics Data System (ADS)

Biseniece, Edite; Freimanis, Ritvars; Purvins, Reinis; Gravelsins, Armands; Pumpurs, Aivars; Blumberga, Andra

2018-03-01

Being an important contributor to the final energy consumption, historic buildings built before 1945 have high specific heating energy consumption compared to current energy standards and norms. However, they often cannot be insulated from the outside due to their heritage and culture value. Internal insulation is an alternative. However internal insulation faces challenges related to hygrothermal behaviour leading to mold growth, freezing, deterioration and other risks. The goal of this research is to link hygrothermal simulation results with experimental results for internally insulated historic brick masonry to assess correlation between simulated and measured data as well as the most influential parameters. The study is carried out by both a mathematical simulation tool and laboratory tests of historic masonry with internal insulation with four insulation materials (mineral wool, EPS, wood fiber and granulated aerogel) in a cold climate (average 4000 heating degree days). We found disparity between measured and simulated hygrothermal performance of studied constructions due to differences in material parameters and initial conditions of materials. The latter plays a more important role than material parameters. Under a steady state of conditions, the condensate tolerating system varies between 72.7 % and 80.5 % relative humidity, but in condensate limiting systems relative humidity variates between 73.3 % and 82.3 %. The temperature between the masonry wall and all insulation materials has stabilized on average at +10 °C. Mold corresponding to Mold index 3 was discovered on wood fiber mat.

Investigation of drying stresses on proteins during lyophilization: differentiation between primary and secondary-drying stresses on lactate dehydrogenase using a humidity controlled mini freeze-dryer.

PubMed

Luthra, Sumit; Obert, Jean-Philippe; Kalonia, Devendra S; Pikal, Michael J

2007-01-01

This article describes the design, performance testing, and application of a controlled humidity mini-freeze-dryer in studying the physical stability of lactate dehydrogenase during lyophilization. Performance evaluation of the mini-freeze-dryer was conducted with tests, namely water sublimation, radiation heat exchange, lowest achievable temperature, and leak testing. Protein stability studies were conducted by comparing protein activity at various stages of lyophilization with the initial activity. The shelf and condenser temperature were stable at <-40 degrees C, wall temperature was within 2 degrees C of the shelf temperature, and the leak rate was small. The chamber pressure was controlled by the ice on the condenser and the product temperature during sublimation was equal to the shelf temperature. Addition of Tween 80 prevented activity loss in solution and after freeze-thaw. No activity loss was observed after primary-drying even in absence of lyoprotectants and with collapse of cake structure. Five percent (w/w) sucrose concentration was required to achieve full stabilization. In conclusion, performance testing established that the mini-freeze-dryer was suitable for mechanistic freeze-drying studies. Secondary-drying was the critical step for protein stability. The concentration of sucrose required to stabilize the protein completely was several orders of magnitude higher than that required to satisfy the direct interaction requirement of the protein. (c) 2006 Wiley-Liss, Inc. and the American Pharmacists Association.

Elimination of laparoscopic lens fogging using directional flow of CO2.

PubMed

Calhoun, John Teague; Redan, Jay A

2014-01-01

Surgeons constantly struggle with the formation of condensation on the lens of a laparoscope, which prolongs procedures and reduces visibility of the abdominal cavity. The goal of this project was to build a device that would direct a flow of carbon dioxide (CO2) into an open chamber surrounding the lens of a laparoscope, acting to keep moisture away from the lens and eliminate condensation. The device isolates the lens of the laparoscope from the humid environment of the intraperitoneal cavity by creating a microenvironment of dry CO2. This was accomplished by building a communicating sleeve that created an open chamber around the distal 2 to 3 cm of the scope. Into this cavity, dry cool CO2 was pumped in from an insufflator so that the path of the gas would surround the lens of the scope and escape through a single outlet location through which the scope views the intraperitoneal cavity. This chamber is proposed to isolate the lens with a high percentage of dry CO2 and low humidity. The device was tested in 7 different adverse conditions that were meant to challenge the ability of the device to maintain the viewing field with no perceptible obstruction. In all of the conditions tested, 25 trials total, the device successfully prevented and/or eliminated laparoscopic lens fogging. The device designed for this project points to the potential of a simple and effective mechanical method for eliminating laparoscopic lens fogging.

EDITORIAL: Humidity sensors Humidity sensors

NASA Astrophysics Data System (ADS)

Regtien, Paul P. L.

2012-01-01

All matter is more or less hygroscopic. The moisture content varies with vapour concentration of the surrounding air and, as a consequence, most material properties change with humidity. Mechanical and thermal properties of many materials, such as the tensile strength of adhesives, stiffness of plastics, stoutness of building and packaging materials or the thermal resistivity of isolation materials, all decrease with increasing environmental humidity or cyclic humidity changes. The presence of water vapour may have a detrimental influence on many electrical constructions and systems exposed to humid air, from high-power systems to microcircuits. Water vapour penetrates through coatings, cable insulations and integrated-circuit packages, exerting a fatal influence on the performance of the enclosed systems. For these and many other applications, knowledge of the relationship between moisture content or humidity and material properties or system behaviour is indispensable. This requires hygrometers for process control or test and calibration chambers with high accuracy in the appropriate temperature and humidity range. Humidity measurement methods can roughly be categorized into four groups: water vapour removal (the mass before and after removal is measured); saturation (the air is brought to saturation and the `effort' to reach that state is measured); humidity-dependent parameters (measurement of properties of humid air with a known relation between a specific property and the vapour content, for instance the refractive index, electromagnetic spectrum and acoustic velocity); and absorption (based on the known relation between characteristic properties of non-hydrophobic materials and the amount of absorbed water from the gas to which these materials are exposed). The many basic principles to measure air humidity are described in, for instance, the extensive compilations by Wexler [1] and Sonntag [2]. Absorption-type hygrometers have small dimensions and can be produced at relatively low cost. Therefore, they find wide use in lots of applications. However, the method requires a material that possesses some conflicting properties: stable and reproducible relations between air humidity, moisture uptake and a specific property (for instance the length of a hair, the electrical impedance of the material), fast absorption and desorption of the water vapour (to obtain a short response time), small hysteresis, wide range of relative humidity (RH) and temperature-independent output (only responsive to RH). For these reasons, much research is done and is still going on to find suitable materials that combine high performance and low price. In this special feature, three of the four papers report on absorption sensors, all with different focus. Aziz et al describe experiments with newly developed materials. The surface structure is extensively studied, in view of its ability to rapidly absorb water vapour and exhibit a reproducible change in the resistance and capacitance of the device. Sanchez et al employ optical fibres coated with a thin moisture-absorbing layer as a sensitive humidity sensor. They have studied various coating materials and investigated the possibility of using changes in optical properties of the fibre (here the lossy mode resonance) due to a change in humidity of the surrounding air. The third paper, by Weremczuk et al, focuses on a cheap fabrication method for absorption-based humidity sensors. The inkjet technology appears to be suitable for mass fabrication of such sensors, which is demonstrated by extensive measurements of the electrical properties (resistance and capacitance) of the absorbing layers. Moreover, they have developed a model that describes the relation between humidity and the electrical parameters of the moisture-sensitive layer. Despite intensive research, absorption sensors still do not meet the requirements for high accuracy applications. The dew-point temperature method is more appropriate, since it uses the accurately known relation between temperature and saturation vapour pressure in air. When an object exposed to humid air is cooled down below the dew-point water vapour condenses as drops on its cold surface. The temperature can be kept exactly at the dew point by controlling the amount of dew (equilibrium between evaporation and condensation). In most dew-point hygrometers dew is detected with optical or capacitive means. In the former the dew drops on a reflective surface (chilled mirror) scatter incident light, and the capacitive method uses the change in capacitance due to the large dielectric constant of liquid water (80) compared to air (1). Kunze et al, in the fourth paper of this special feature, use another property of water to detect dew: the relatively high value of the thermal capacitance of liquid water. In traditional technology this method would not be sensitive enough, but with MEMS technology a sufficient detectivity of dew can be achieved, which is demonstrated in this paper. A control system keeps the temperature of the substrate just at the dew-point temperature, the latter being measured by an on-chip diode. The accuracy achieved is comparable with traditional dew-point hygrometers. These four papers in this issue are nice examples of research leading to significant advances in hygrometry. References [1] Wexler A (ed) 1965 Humidity and Moisture. Vol. I: Principles and Methods of Measuring Humidity in Gases; Vol. II: Applications; Vol. III: Fundamentals and Standards; Vol. IV: Principles and Methods of Measuring Moisture in Liquids and Solids (New York: Reinhold) [2] Sonntag D 1966-1968 Hygrometrie (Berlin: Akademie Verlag)

Cabin safety subject index.

DOT National Transportation Integrated Search

1984-01-01

The most frequently used Federal Aviation Administration published cabin safety information is indexed and cross referenced. This includes Federal Aviation Regulations numbers, Air Carrier Operations Bulletin numbers, Advisory Circular numbers, and O...

Experimental evaluation of automotive air-conditioning using HFC-134a and HC-134a

NASA Astrophysics Data System (ADS)

Nasution, Henry; Zainudin, Muhammad Amir; Aziz, Azhar Abdul; Latiff, Zulkarnain Abdul; Perang, Mohd Rozi Mohd; Rahman, Abd Halim Abdul

2012-06-01

An experimental study to evaluate the energy consumption of an automotive air conditioning is presented. In this study, these refrigerants will be tested using the experimental rig which simulated the actual cars as a cabin complete with a cooling system component of the actual car that is as the blower, evaporator, condenser, radiators, electric motor, which acts as a vehicle engine, and then the electric motor will operate the compressor using a belt and pulley system, as well as to the alternator will recharge the battery. The compressor working with the fluids HFC-134a and HC-134a and has been tested varying the speed in the range 1000, 1500, 2000 and 2500 rpm. The measurements taken during the one hour experimental periods at 2-minutes interval times for temperature setpoint of 20°C with internal heat loads 0, 500, 700 and 1000 W. The final results of this study show an overall better energy consumption of the HFC-134a compared with the HC-134a.

Operational Experience with the Internal Thermal Control System Dual-Membrane Gas Trap

NASA Technical Reports Server (NTRS)

Leimkuehler, Thomas O.; Lukens, Clark; Reeves, Daniel R.; Holt, James M.

2003-01-01

A dual-membrane gas trap is currently used to remove non-condensed gases (NCG) from the Internal Thermal Control System (ITCS) coolant on board the International Space Station. The gas trap consists of concentric tube membrane pairs, comprised of outer hydrophilic tubes and inner hydrophobic fibers. Liquid coolant passes through the outer hydrophilic membrane, which traps the NCG. The inner hydrophobic fiber allows the trapped NCG to pass through and vent to the ambient atmosphere in the cabin. The purpose of the gas trap is to prevent gas bubbles from causing depriming, overspeed, and shutdown of the ITCS pump, and the current gas trap has performed flawlessly in this regard. However, because of actual operational conditions on-orbit, its gas removal performance and operational lifetime have been affected. This paper discusses experiences with several of these dual- membrane gas traps, including on-orbit gas venting rate, effects due to the presence of nickel in the ITCS coolant, and subsequent refurbishing to remove the nickel from the gas trap.

A Water Recovery System Evolved for Exploration

NASA Technical Reports Server (NTRS)

ORourke, Mary Jane E.; Perry, Jay L.; Carter, Donald L.

2006-01-01

A new water recovery system designed towards fulfillment of NASA's Vision for Space Exploration is presented. This water recovery system is an evolution of the current state-of-the-art system. Through novel integration of proven technologies for air and water purification, this system promises to elevate existing technology to higher levels of optimization. The novel aspect of the system is twofold: Volatile organic contaminants will be removed from the cabin air via catalytic oxidation in the vapor phase, prior to their absorption into the aqueous phase, and vapor compression distillation technology will be used to process the condensate and hygiene waste streams in addition to the urine waste stream. Oxidation kinetics dictate that removal of volatile organic contaminants from the vapor phase is more efficient. Treatment of the various waste streams by VCD will reduce the load on the expendable ion exchange and adsorption media which follow, and on the aqueous-phase volatile removal assembly further downstream. Incorporating these advantages will reduce the weight, volume, and power requirements of the system, as well as resupply.

Simultaneous measurements of ozone outside and inside cabins of two B-747 airliners and a Gates Learjet business jet

NASA Technical Reports Server (NTRS)

Perkins, P. J.; Briehl, D.

1978-01-01

Recently, passengers and crew members on long-distance commercial flights have filed complaints after suffering symptoms of ozone sickness. Studies were conducted to determine the frequency and concentration of ozone in commercial jet transports. The airliner problem with ozone prompted NASA to determine the ozone concentrations that might be encountered in the cabin of a small business jet. Simultaneous measurements of atmospheric ozone levels and ozone levels in the cabins of jet aircraft were necessary because of the wide and rapid variability of atmospheric ozone in flight. It was found that the atmospheric ozone concentrations in the case of B-747 airliners vary widely during a flight. A constant difference, or ratio, between ozone concentrations outside and inside the cabin does not exist.

Exhaled nitric oxide levels in school children in relation to IgE sensitisation and window pane condensation.

PubMed

Janson, Christer; Kalm-Stephens, Pia; Foucard, Tony; Norbäck, Dan; Alving, Kjell; Nordvall, S Lennart

2005-08-01

A positive relation between exhaled nitric oxide (NO) levels and allergen exposure has been found in some studies whereas there is less information on how non-allergen environmental factors influences exhaled NO. To study the relationship between exhaled NO levels in schoolchildren in relation to IgE sensitisation and allergenic and non-allergenic environmental factors. This study comprised 374 schoolchildren (13-14 years of age) who performed exhaled NO-measurements and skin prick tests. Exposure to allergens, respiratory infections, environmental tobacco smoke and home window pane condensation, the latter an indicator of high humidity and poor ventilation was evaluated through questionnaires. In IgE-sensitised children sensitisation to pets was a more important determinant of exhaled NO than sensitisation to pollen. Higher NO levels were found in cat-sensitised children with a cat or other furred pets at home compared to cat-sensitised children without pets (geometric mean, 24.0 vs. 13.9 ppb, P=0.03). Significantly higher exhaled NO levels were found in non-sensitised children that reported having a cold (5.7 vs. 3.8 ppb, P<0.001) or lived in homes with window pane condensation (7.1 vs. 4.4 ppb, P=0.01) than in non-sensitised children without a cold and window pane condensation, respectively. These associations were not found in children that were sensitised to inhalation allergens. Allergen exposure seems to be the most important determinant for exhaled NO levels in IgE-sensitised children whereas in non-sensitised children NO levels were associated with respiratory infections and home window pane condensation.

Jumping-droplet electronics hot-spot cooling

NASA Astrophysics Data System (ADS)

Oh, Junho; Birbarah, Patrick; Foulkes, Thomas; Yin, Sabrina L.; Rentauskas, Michelle; Neely, Jason; Pilawa-Podgurski, Robert C. N.; Miljkovic, Nenad

2017-03-01

Demand for enhanced cooling technologies within various commercial and consumer applications has increased in recent decades due to electronic devices becoming more energy dense. This study demonstrates jumping-droplet based electric-field-enhanced (EFE) condensation as a potential method to achieve active hot spot cooling in electronic devices. To test the viability of EFE condensation, we developed an experimental setup to remove heat via droplet evaporation from single and multiple high power gallium nitride (GaN) transistors acting as local hot spots (4.6 mm × 2.6 mm). An externally powered circuit was developed to direct jumping droplets from a copper oxide (CuO) nanostructured superhydrophobic surface to the transistor hot spots by applying electric fields between the condensing surface and the transistor. Heat transfer measurements were performed in ambient air (22-25 °C air temperature, 20%-45% relative humidity) to determine the effect of gap spacing (2-4 mm), electric field (50-250 V/cm) and applied heat flux (demonstrated to 13 W/cm2). EFE condensation was shown to enhance the heat transfer from the local hot spot by ≈200% compared to cooling without jumping and by 20% compared to non-EFE jumping. Dynamic switching of the electric field for a two-GaN system reveals the potential for active cooling of mobile hot spots. The opportunity for further cooling enhancement by the removal of non-condensable gases promises hot spot heat dissipation rates approaching 120 W/cm2. This work provides a framework for the development of active jumping droplet based vapor chambers and heat pipes capable of spatial and temporal thermal dissipation control.

13. View of swing span showing bridge operator's control cabin, ...

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

13. View of swing span showing bridge operator's control cabin, looking northeast - India Point Railroad Bridge, Spanning Seekonk River between Providence & East Providence, Providence, Providence County, RI

11. View of bridge operator's control cabin from Seekonk River ...

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

11. View of bridge operator's control cabin from Seekonk River looking northwest - India Point Railroad Bridge, Spanning Seekonk River between Providence & East Providence, Providence, Providence County, RI

Performance Evaluation of a Mechanical Draft Cross Flow Cooling Towers Employed in a Subtropical Region

NASA Astrophysics Data System (ADS)

Muthukumar, Palanisamy; Naik, Bukke Kiran; Goswami, Amarendra

2018-02-01

Mechanical draft cross flow cooling towers are generally used in a large-scale water cooled condenser based air-conditioning plants for removing heat from warm water which comes out from the condensing unit. During this process considerable amount of water in the form of drift (droplets) and evaporation is carried away along with the circulated air. In this paper, the performance evaluation of a standard cross flow induced draft cooling tower in terms of water loss, range, approach and cooling tower efficiency are presented. Extensive experimental studies have been carried out in three cooling towers employed in a water cooled condenser based 1200 TR A/C plant over a period of time. Daily variation of average water loss and cooling tower performance parameters have been reported for some selected days. The reported average water loss from three cooling towers is 4080 l/h and the estimated average water loss per TR per h is about 3.1 l at an average relative humidity (RH) of 83%. The water loss during peak hours (2 pm) is about 3.4 l/h-TR corresponding to 88% of RH and the corresponding efficiency of cooling towers varied between 25% and 45%.

Jumping-Droplet Condensation Drives Pathogen Transport on Wheat Leaves

NASA Astrophysics Data System (ADS)

Nath, Saurabh; Gruszewski, Hope; Budhiraja, Stuti; Ahmadi, Farzad; Bisbano, Caitlin; Jung, Sunghwan; Schmale, David, III; Boreyko, Jonathan

2017-11-01

The classical viewpoint in phytopathology regarding how plant pathogens are liberated is based on active mechanisms such as shearing off spores via rain splash or wind. All of these mechanisms require some kind of impact on the surface. Here we show for the first time that there exists an entirely different mechanism in nature that drives pathogen transport on wheat leaves. Wheat leaves are inherently superhydrophobic, which enables microscopic dew droplets to spontaneously jump off the leaf surface during natural condensation cycles. We found that black rust (Puccinia graminis) spores often adhere to such coalescence-induced self-propelled dew droplets and subsequently get transported vertically as high as 5 mm. Once pathogens clear the quiescent boundary layer, typically of order 1 mm, they have the potential to be dispersed over large distances by the aid of atmospheric flows. A custom-made experimental set-up was devised to simulate multiple one hour long natural dew cycles and how they affect spore dispersal. Spore liberation rates via jumping-droplet condensation were found to be as high 100 spores/cm2-hr. These findings reveal that on a sufficiently non-wetting surface humidity alone can liberate fungal spores, adding it as a third mechanism besides wind and rain.

A Design Basis for Spacecraft Cabin Trace Contaminant Control

NASA Technical Reports Server (NTRS)

Perry, Jay L.

2009-01-01

Successful trace chemical contamination control is one of the components necessary for achieving good cabin atmospheric quality. While employing seemingly simple process technologies, sizing the active contamination control equipment must employ a reliable design basis for the trace chemical load in the cabin atmosphere. A simplified design basis that draws on experience gained from the International Space Station program is presented. The trace chemical contamination control design load refines generation source magnitudes and includes key chemical functional groups representing both engineering and toxicology challenges.

77 FR 53212 - Federal Property Suitable as Facilities To Assist the Homeless

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-31

... Buildings Duplex Cabins Yosemite CA 95389 Landholding Agency: Interior Property Number: 61201230009 Status... details 33 Buildings Duplex Cabins Yosemite CA 95389 Landholding Agency: Interior Property Number...

36 CFR 13.104 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... definitions apply to this subpart: Cabin means a small, usually one-story dwelling of simple construction... claimant or of the claimant's spouse. Possessory interest means the partial or total ownership of a cabin...

Crew Survivability After a Rapid Cabin Depressurization Event

NASA Technical Reports Server (NTRS)

Sargusingh, Miriam J.

2012-01-01

Anecdotal evidence acquired through historic failure investigations involving rapid cabin decompression (e.g. Challenger, Columbia and Soyuz 11) show that full evacuation of the cabin atmosphere may occur within seconds. During such an event, the delta-pressure between the sealed suit ventilation system and the cabin will rise at the rate of the cabin depressurization; potentially at a rate exceeding the capability of the suit relief valve. It is possible that permanent damage to the suit pressure enclosure and ventilation loop components may occur as the integrated system may be subjected to delta pressures in excess of the design-to pressures. Additionally, as the total pressure of the suit ventilation system decreases, so does the oxygen available to the crew. The crew may be subjected to a temporarily incapacitating, but non-lethal, hypoxic environment. It is expected that the suit will maintain a survivable atmosphere on the crew until the vehicle pressure control system recovers or the cabin has otherwise attained a habitable environment. A common finding from the aforementioned reports indicates that the crew would have had a better chance at surviving the event had they been in a protective configuration, that is, in a survival suit. Making use of these lessons learned, the Constellation Program implemented a suit loop in the spacecraft design and required that the crew be in a protective configuration, that is suited with gloves on and visors down, during dynamic phases of flight that pose the greatest risk for a rapid and uncontrolled cabin depressurization event: ascent, entry, and docking. This paper details the evaluation performed to derive suit pressure garment and ventilation system performance parameters that would lead to the highest probability of crew survivability after an uncontrolled crew cabin depressurization event while remaining in the realm of practicality for suit design. This evaluation involved: (1) assessment of stakeholder expectations to validate the functionality being imposed; (2) review/refinement of concept of operations to establish the potential triggers for such an event and define the response of the spacecraft and suit ventilation loop pressure control systems; and (3) assessment of system capabilities with respect to structural capability and pressure control.

17. DETAIL VIEW OF CUPOLA ATOP OPERATOR'S CABIN WHICH MOUNTS ...

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

17. DETAIL VIEW OF CUPOLA ATOP OPERATOR'S CABIN WHICH MOUNTS SIGNAL HORNS, WEATHER VANE - Sacramento River Bridge, Spanning Sacramento River at California State Highway 275, Sacramento, Sacramento County, CA

Cooling performance and evaluation of automotive refrigeration system for a passenger car

NASA Astrophysics Data System (ADS)

Prajitno, Deendarlianto, Majid, Akmal Irfan; Mardani, Mahardeka Dhias; Wicaksono, Wendi; Kamal, Samsul; Purwanto, Teguh Pudji; Fauzun

2016-06-01

A new design of automotive refrigeration system for a passenger car was proposed. To ensure less energy consumption and optimal thermal comfort, the performance of the system were evaluated. This current research was aimed to evaluate the refrigeration characteristics of the system for several types of cooling load. In this present study, a four-passenger wagon car with 1500 cc gasoline engine that equipped by a belt driven compressor (BDC) was used as the tested vehicle. To represent the tropical condition, a set of lamps and wind sources are installed around the vehicle. The blower capacity inside a car is varied from 0.015 m/s to 0.027 m/s and the compressor speed is varied at variable 820, 1400, and 2100 rpm at a set temperature of 22°C. A set of thermocouples that combined by data logger were used to measure the temperature distribution. The system uses R-134a as the refrigerant. In order to determine the cooling capacity of the vehicle, two conditions were presented: without passengers and full load conditions. As the results, cooling capacity from any possible heating sources and transient characteristics of temperature in both systems for the cabin, engine, compressor, and condenser are presented in this work. As the load increases, the outlet temperature of evaporator also increases due to the increase of condensed air. This phenomenon also causes the increase of compressor work and compression ratio which associated to the addition of specific volume in compressor inlet.

1. Historic American Buildings Survey L. D. Andrew, Photographer Enlarged ...

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

1. Historic American Buildings Survey L. D. Andrew, Photographer Enlarged Photographed by Harold Bush-Brown Nov. 14, 1936 GENERAL VIEW OF SLAVE CABINS - Bass Place (Slave Cabins), Columbus, Muscogee County, GA

2. Historic American Buildings Survey L. D. Andrew, Photographer, Enlarged ...

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

2. Historic American Buildings Survey L. D. Andrew, Photographer, Enlarged Photographed by Harold Bush-Brown Nov. 14, 1936 VIEW OF EASTERN SLAVE CABIN - Bass Place (Slave Cabins), Columbus, Muscogee County, GA

Formaldehyde Concentration Dynamics of the International Space Station Cabin Atmosphere

NASA Technical Reports Server (NTRS)

Perry, J. L.

2005-01-01

Formaldehyde presents a significant challenge to maintaining cabin air quality on board crewed spacecraft. Generation sources include offgassing from a variety of non-metallic materials as well as human metabolism. Because generation sources are pervasive and human health can be affected by continual exposure to low concentrations, toxicology and air quality control engineering experts jointly identified formaldehyde as a key compound to be monitored as part the International Space Station's (ISS) environmental health monitoring and maintenance program. Data acquired from in-flight air quality monitoring methods are the basis for assessing the cabin environment's suitability for long-term habitation and monitoring the performance of passive and active controls that are in place to minimize crew exposure. Formaldehyde concentration trends and dynamics served in the ISS cabin atmosphere are reviewed implications to present and future flight operations discussed.

Study of the effect of space cabin environment on susceptibility to disease

NASA Technical Reports Server (NTRS)

1972-01-01

Decreased resistance to infections initiated by respiratory challenge with Klebsiella pneumoniae or influenza virus was observed in mice maintained in a simulated space cabin environment represented by 98% oxygen atmosphere and 27,000 ft altitude (5 psi). The reduced resistance was manifested by increased mortality rates as compared to those seen in mice maintained at ground level condition. However, an adaptation to the stress appeared to be present in mice exposed to the space cabin environment for extended time period, i.e. 36 days, and then challenged with the influenza virus. Reduced resistance was not observed when Salmonella typhimurium was used as the challenge agent. Histopathologic examination of lungs of mice indicated that the severity of damage appeared to be related to the duration of exposure to the simulated space cabin environment.

The Incidence and Fate of Volatile Methyl Siloxanes in a Crewed Spacecraft Cabin

NASA Technical Reports Server (NTRS)

Perry, Jay L.; Kayatin, Matthew J.

2017-01-01

Volatile methyl siloxanes (VMS) arise from diverse, pervasive sources aboard crewed spacecraft ranging from materials offgassing to volatilization from personal care products. These sources lead to a persistent VMS compound presence in the cabin environment that must be considered for robust life support system design. Volatile methyl siloxane compound stability in the cabin environment presents an additional technical issue because degradation products such as dimethylsilanediol (DMSD) are highly soluble in water leading to a unique load challenge for water purification processes. The incidence and fate of VMS compounds as observed in the terrestrial atmosphere, water, and surface (soil) environmental compartments have been evaluated as an analogy for a crewed cabin environment. Volatile methyl siloxane removal pathways aboard crewed spacecraft are discussed and a material balance accounting for a DMSD production mechanism consistent with in-flight observations is presented.

Source apportionment of airborne particles in commercial aircraft cabin environment: Contributions from outside and inside of cabin

NASA Astrophysics Data System (ADS)

Li, Zheng; Guan, Jun; Yang, Xudong; Lin, Chao-Hsin

2014-06-01

Airborne particles are an important type of air pollutants in aircraft cabin. Finding sources of particles is conducive to taking appropriate measures to remove them. In this study, measurements of concentration and size distribution of particles larger than 0.3 μm (PM>0.3) were made on nine short haul flights from September 2012 to March 2013. Particle counts in supply air and breathing zone air were both obtained. Results indicate that the number concentrations of particles ranged from 3.6 × 102 counts L-1 to 1.2 × 105 counts L-1 in supply air and breathing zone air, and they first decreased and then increased in general during the flight duration. Peaks of particle concentration were found at climbing, descending, and cruising phases in several flights. Percentages of particle concentration in breathing zone contributed by the bleed air (originated from outside) and cabin interior sources were calculated. The bleed air ratios, outside airflow rates and total airflow rates were calculated by using carbon dioxide as a ventilation tracer in five of the nine flights. The calculated results indicate that PM>0.3 in breathing zone mainly came from unfiltered bleed air, especially for particle sizes from 0.3 to 2.0 μm. And for particles larger than 2.0 μm, contributions from the bleed air and cabin interior were both important. The results would be useful for developing better cabin air quality control strategies.