Modeling Validation and Control Analysis for Controlled Temperature and Humidity of Air Conditioning System

PubMed Central

Lee, Jing-Nang; Lin, Tsung-Min

2014-01-01

This study constructs an energy based model of thermal system for controlled temperature and humidity air conditioning system, and introduces the influence of the mass flow rate, heater and humidifier for proposed control criteria to achieve the controlled temperature and humidity of air conditioning system. Then, the reliability of proposed thermal system model is established by both MATLAB dynamic simulation and the literature validation. Finally, the PID control strategy is applied for controlling the air mass flow rate, humidifying capacity, and heating, capacity. The simulation results show that the temperature and humidity are stable at 541 sec, the disturbance of temperature is only 0.14°C, 0006 kgw/kgda in steady-state error of humidity ratio, and the error rate is only 7.5%. The results prove that the proposed system is an effective controlled temperature and humidity of an air conditioning system. PMID:25250390

Variable temperature seat climate control system

DOEpatents

Karunasiri, Tissa R.; Gallup, David F.; Noles, David R.; Gregory, Christian T.

1997-05-06

A temperature climate control system comprises a variable temperature seat, at least one heat pump, at least one heat pump temperature sensor, and a controller. Each heat pump comprises a number of Peltier thermoelectric modules for temperature conditioning the air in a main heat exchanger and a main exchanger fan for passing the conditioned air from the main exchanger to the variable temperature seat. The Peltier modules and each main fan may be manually adjusted via a control switch or a control signal. Additionally, the temperature climate control system may comprise a number of additional temperature sensors to monitor the temperature of the ambient air surrounding the occupant as well as the temperature of the conditioned air directed to the occupant. The controller is configured to automatically regulate the operation of the Peltier modules and/or each main fan according to a temperature climate control logic designed both to maximize occupant comfort during normal operation, and minimize possible equipment damage, occupant discomfort, or occupant injury in the event of a heat pump malfunction.

Coolant and ambient temperature control for chillerless liquid cooled data centers

DOEpatents

Chainer, Timothy J.; David, Milnes P.; Iyengar, Madhusudan K.; Parida, Pritish R.; Simons, Robert E.

2017-08-29

Cooling control methods and systems include measuring a temperature of air provided to one or more nodes by an air-to-liquid heat exchanger; measuring a temperature of at least one component of the one or more nodes and finding a maximum component temperature across all such nodes; comparing the maximum component temperature to a first and second component threshold and comparing the air temperature to a first and second air threshold; and controlling a proportion of coolant flow and a coolant flow rate to the air-to-liquid heat exchanger and the one or more nodes based on the comparisons.

Apparatus and Method for Measuring Air Temperature Ahead of an Aircraft for Controlling a Variable Inlet/Engine Assembly

NASA Technical Reports Server (NTRS)

Gary, Bruce L. (Inventor)

2001-01-01

The apparatus and method employ remote sensing to measure the air temperature a sufficient distance ahead of the aircraft to allow time for a variable inlet/engine assembly to be reconfigured in response to the measured temperature, to avoid inlet unstart and/or engine compressor stall. In one embodiment, the apparatus of the invention has a remote sensor for measuring at least one air temperature ahead of the vehicle and an inlet control system for varying the inlet. The remote sensor determines a change in temperature value using at least one temperature measurement and prior temperature measurements corresponding to the location of the aircraft. The control system uses the change in air temperature value to vary the inlet configuration to maintain the position of the shock wave during the arrival of the measured air in the inlet. In one embodiment, the method of the invention includes measuring at least one air temperature ahead of the vehicle, determining an air temperature at the vehicle from prior air temperature measurements, determining a change in temperature value using the air temperature at the vehicle and the at least one air temperature measurement ahead of the vehicle, and using the change in temperature value to-reposition the airflow inlet, to cause the shock wave to maintain substantially the same position within the inlet as the airflow temperature changes within the inlet.

Incubator temperature control: effects on the very low birthweight infant.

PubMed Central

Ducker, D A; Lyon, A J; Ross Russell, R; Bass, C A; McIntosh, N

1985-01-01

We studied temperature stability in 22 infants of birthweight less than 1500 g in the first four days of life. Infants were nursed in incubators using either air mode control or skin temperature servo control. Data were collected continuously using a computer linked monitoring system. Skin temperature control resulted in a less stable thermal environment than air mode control. Increased thermal stability in the incubator on air mode control may well be beneficial, particularly to sick, very low birthweight infants. PMID:4062342

System for controlling the operating temperature of a fuel cell

DOEpatents

Fabis, Thomas R.; Makiel, Joseph M.; Veyo, Stephen E.

2006-06-06

A method and system are provided for improved control of the operating temperature of a fuel cell (32) utilizing an improved temperature control system (30) that varies the flow rate of inlet air entering the fuel cell (32) in response to changes in the operating temperature of the fuel cell (32). Consistent with the invention an improved temperature control system (30) is provided that includes a controller (37) that receives an indication of the temperature of the inlet air from a temperature sensor (39) and varies the heat output by at least one heat source (34, 36) to maintain the temperature of the inlet air at a set-point T.sub.inset. The controller (37) also receives an indication of the operating temperature of the fuel cell (32) and varies the flow output by an adjustable air mover (33), within a predetermined range around a set-point F.sub.set, in order to maintain the operating temperature of the fuel cell (32) at a set-point T.sub.opset.

Gas turbine engine active clearance control

NASA Technical Reports Server (NTRS)

Deveau, Paul J. (Inventor); Greenberg, Paul B. (Inventor); Paolillo, Roger E. (Inventor)

1985-01-01

Method for controlling the clearance between rotating and stationary components of a gas turbine engine are disclosed. Techniques for achieving close correspondence between the radial position of rotor blade tips and the circumscribing outer air seals are disclosed. In one embodiment turbine case temperature modifying air is provided in flow rate, pressure and temperature varied as a function of engine operating condition. The modifying air is scheduled from a modulating and mixing valve supplied with dual source compressor air. One source supplies relatively low pressure, low temperature air and the other source supplies relatively high pressure, high temperature air. After the air has been used for the active clearance control (cooling the high pressure turbine case) it is then used for cooling the structure that supports the outer air seal and other high pressure turbine component parts.

Apparatus for supplying conditioned air at a substantially constant temperature and humidity

NASA Technical Reports Server (NTRS)

Obler, H. D. (Inventor)

1980-01-01

The apparatus includes a supply duct coupled to a source of supply air for carrying the supply air therethrough. A return duct is coupled to the supply duct for carrying return conditioned air therethrough. A temperature reducing device is coupled to the supply duct for decreasing the temperature of the supply and return conditioned air. A by-pass duct is coupled to the supply duct for selectively directing portions of the supply and return conditioned air around the temperature reducing device. Another by-pass duct is coupled to the return duct for selectively directing portions of the return conditioned air around the supply duct and the temperature reduction device. Controller devices selectively control the flow and amount of mixing of the supply and return conditioned air.

Planar solid oxide fuel cell with staged indirect-internal air and fuel preheating and reformation

DOEpatents

Geisbrecht, Rodney A; Williams, Mark C

2003-10-21

A solid oxide fuel cell arrangement and method of use that provides internal preheating of both fuel and air in order to maintain the optimum operating temperature for the production of energy. The internal preheat passes are created by the addition of two plates, one on either side of the bipolar plate, such that these plates create additional passes through the fuel cell. This internal preheat fuel cell configuration and method reduce the requirements for external heat exchanger units and air compressors. Air or fuel may be added to the fuel cell as required to maintain the optimum operating temperature through a cathode control valve or an anode control valve, respectively. A control loop comprises a temperature sensing means within the preheat air and fuel passes, a means to compare the measured temperature to a set point temperature and a determination based on the comparison as to whether the control valves should allow additional air or fuel into the preheat or bypass manifolds of the fuel cell.

Control methods and systems for indirect evaporative coolers

DOEpatents

Woods, Jason; Kozubal, Erik

2015-09-22

A control method for operating an indirect evaporative cooler to control temperature and humidity. The method includes operating an airflow control device to provide supply air at a flow rate to a liquid desiccant dehumidifier. The supply air flows through the dehumidifier and an indirect evaporative cooler prior to exiting an outlet into a space. The method includes operating a pump to provide liquid desiccant to the liquid desiccant dehumidifier and sensing a temperature of an airstream at the outlet of the indirect evaporative cooler. The method includes comparing the temperature of the airstream at the outlet to a setpoint temperature at the outlet and controlling the pump to set the flow rate of the liquid desiccant. The method includes sensing space temperature, comparing the space temperature with a setpoint temperature, and controlling the airflow control device to set the flow rate of the supply air based on the comparison.

Assimilation of Quality Controlled AIRS Temperature Profiles using the NCEP GFS

NASA Technical Reports Server (NTRS)

Susskind, Joel; Reale, Oreste; Iredell, Lena; Rosenberg, Robert

2013-01-01

We have previously conducted a number of data assimilation experiments using AIRS Version-5 quality controlled temperature profiles as a step toward finding an optimum balance of spatial coverage and sounding accuracy with regard to improving forecast skill. The data assimilation and forecast system we used was the Goddard Earth Observing System Model , Version-5 (GEOS-5) Data Assimilation System (DAS), which represents a combination of the NASA GEOS-5 forecast model with the National Centers for Environmental Prediction (NCEP) operational Grid Point Statistical Interpolation (GSI) global analysis scheme. All analyses and forecasts were run at a 0.5deg x 0.625deg spatial resolution. Data assimilation experiments were conducted in four different seasons, each in a different year. Three different sets of data assimilation experiments were run during each time period: Control; AIRS T(p); and AIRS Radiance. In the "Control" analysis, all the data used operationally by NCEP was assimilated, but no AIRS data was assimilated. Radiances from the Aqua AMSU-A instrument were also assimilated operationally by NCEP and are included in the "Control". The AIRS Radiance assimilation adds AIRS observed radiance observations for a select set of channels to the data set being assimilated, as done operationally by NCEP. In the AIRS T(p) assimilation, all information used in the Control was assimilated as well as Quality Controlled AIRS Version-5 temperature profiles, i.e., AIRS T(p) information was substituted for AIRS radiance information. The AIRS Version-5 temperature profiles were presented to the GSI analysis as rawinsonde profiles, assimilated down to a case-by-case appropriate pressure level p(sub best) determined using the Quality Control procedure. Version-5 also determines case-by-case, level-by-level error estimates of the temperature profiles, which were used as the uncertainty of each temperature measurement. These experiments using GEOS-5 have shown that forecasts resulting from analyses using the AIRS T(p) assimilation system were superior to those from the Radiance assimilation system, both with regard to global 7 day forecast skill and also the ability to predict storm tracks and intensity.

Temperature offset control system

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

Fried, M.

1987-07-28

This patent describes a temperature offset control system for controlling the operation of both heating and air conditioning systems simultaneously contained within the same premises each of which is set by local thermostats to operate at an appropriate temperature, the offset control system comprising: a central control station having means for presetting an offset temperature range, means for sensing the temperature at a central location, means for comparing the sensed temperature with the offset temperature range, means responsive to the comparison for producing a control signal indicative of whether the sensed temperature is within the offset temperature range or beyondmore » the offset temperature range, and means for transmitting the control signal onto the standard energy lines servicing the premises; and a receiving station respectively associated with each heating and air conditioning system, the receiving stations each comprising means for receiving the same transmitted control signal from the energy lines, and switch means for controlling the energization of the respective system in response to the received control signal. The heating systems and associated local thermostat are disabled by the control signal when the control signal originates from a sensed temperature above the lower end of the offset temperature range. The air conditioning systems and associated thermostats are disabled by the same control signal when the control signal originates from a sensed temperature below the upper end of the offset temperature range.« less

Controlled-Temperature Hot-Air Gun

NASA Technical Reports Server (NTRS)

Munoz, M. C.

1986-01-01

Materials that find applications in wind tunnels first tested in laboratory. Hot-Air Gun differs from commercial units in that flow rate and temperature monitored and controlled. With typical compressed-airsupply pressure of 25 to 38 psi (170 to 260 kPa), flow rate and maximum temperature are 34 stdft3/min (0.96 stdm3/min) and 1,090 degrees F (590 degrees C), respectively. Resembling elaborate but carefully regulated hot-air gun, setup used to apply blasts of air temperatures above 1,500 degrees F (815 degrees C) to test specimens.

Soil and air temperature and biomass after residue treatment.

Treesearch

W.B. Fowler; J.D. Helvey

1981-01-01

Air temperature at 0.5 m and soil temperature at 0.01 m were measured during May and early June after forest harvest on four residue treatment sites and a control. Broadcast burning or burning in piles increased daily accumulation of heat in air while scattered chips and scarified and cleared treatments were equal to the control (broadcast, untreated slash). During mid...

System and method for air temperature control in an oxygen transport membrane based reactor

DOEpatents

Kelly, Sean M

2016-09-27

A system and method for air temperature control in an oxygen transport membrane based reactor is provided. The system and method involves introducing a specific quantity of cooling air or trim air in between stages in a multistage oxygen transport membrane based reactor or furnace to maintain generally consistent surface temperatures of the oxygen transport membrane elements and associated reactors. The associated reactors may include reforming reactors, boilers or process gas heaters.

Improving Forecast Skill by Assimilation of AIRS Temperature Soundings

NASA Technical Reports Server (NTRS)

Susskind, Joel; Reale, Oreste

2010-01-01

AIRS was launched on EOS Aqua on May 4, 2002, together with AMSU-A and HSB, to form a next generation polar orbiting infrared and microwave atmospheric sounding system. The primary products of AIRS/AMSU-A are twice daily global fields of atmospheric temperature-humidity profiles, ozone profiles, sea/land surface skin temperature, and cloud related parameters including OLR. The AIRS Version 5 retrieval algorithm, is now being used operationally at the Goddard DISC in the routine generation of geophysical parameters derived from AIRS/AMSU data. A major innovation in Version 5 is the ability to generate case-by-case level-by-level error estimates delta T(p) for retrieved quantities and the use of these error estimates for Quality Control. We conducted a number of data assimilation experiments using the NASA GEOS-5 Data Assimilation System as a step toward finding an optimum balance of spatial coverage and sounding accuracy with regard to improving forecast skill. The model was run at a horizontal resolution of 0.5 deg. latitude X 0.67 deg longitude with 72 vertical levels. These experiments were run during four different seasons, each using a different year. The AIRS temperature profiles were presented to the GEOS-5 analysis as rawinsonde profiles, and the profile error estimates delta (p) were used as the uncertainty for each measurement in the data assimilation process. We compared forecasts analyses generated from the analyses done by assimilation of AIRS temperature profiles with three different sets of thresholds; Standard, Medium, and Tight. Assimilation of Quality Controlled AIRS temperature profiles significantly improve 5-7 day forecast skill compared to that obtained without the benefit of AIRS data in all of the cases studied. In addition, assimilation of Quality Controlled AIRS temperature soundings performs better than assimilation of AIRS observed radiances. Based on the experiments shown, Tight Quality Control of AIRS temperature profile performs best on the average from the perspective of improving Global 7 day forecast skill.

Low-temperature forced-air drying of Appalachian hardwoods

Treesearch

Donald G. Cuppett; E. Paul Craft

1975-01-01

Low-temperature forced-air drying involves drying green lumber in heated buildings with forced-air circulation and partial control of temperature and humidity conditions. The lumber is dried to about 20 percent moisture content at dry-bulb temperatures of 70º to 110ºF and with air velocities of 300 to 600 feet per minute. Equipment, methods, and...

Method and apparatus for controlling the solenoid current of a solenoid valve which controls the amount of suction of air in an internal combustion engine

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

Kiuchi, T.; Yasuoka, A.

1988-05-24

A method of controlling the solenoid current of a solenoid valve which controls suction air in an internal combustion engine, is described comprising the steps of: calculating a solenoid current control value as a function of engine operating conditions; detecting an engine coolant temperature corresponding to the solenoid temperature; determining a temperature correction value in accordance with the solenoid temperature; and calculating a driving signal for controlling the operation of the solenoid as a function of the solenoid current control value and the temperature correction value.

Installation of PMV Operation Program in DDC Controller and Air Conditioning Control Using PMV Directly as Set Point

NASA Astrophysics Data System (ADS)

Haramoto, Ken-Ichi

In general, air conditioning control in a building is operated mainly by indoor air temperature control. Although the operators of the machine in the building accepted a claim for indoor air temperature presented by the building inhabitants, the indoor conditions have been often too cool or warm. Therefore, in an attempt to create better thermal environments, the author paid attention to the PMV that is a thermal comfort index. And then, the possibility of air conditioning control using the PMV directly as the set point was verified by employing actual equipment in an air conditioning testing room and an office building. Prior to the execution of this control, the operation program of the PMV was installed in a DDC controller for the air conditioning control. And information from indoor sensors and so on was inputted to the controller, and the computed PMV was used as the feedback variable.

Servo-control for maintaining abdominal skin temperature at 36C in low birth weight infants.

PubMed

Sinclair, J C

2000-01-01

Randomized trials have shown that the neonatal mortality rate of low birth-weight babies can be reduced by keeping them warm. For low birth-weight babies nursed in incubators, warm conditions may be achieved either by heating the air to a desired temperature, or by servo-controlling the baby's body temperature at a desired set-point. In low birth weight infants, to determine the effect on death and other important clinical outcomes of targeting body temperature rather than air temperature as the end-point of control of incubator heating. Standard search strategy of the Cochrane Neonatal Collaborative Review Group. Randomized or quasi-randomized trials which test the effects of having the heat output of the incubator servo-controlled from body temperature compared with setting a constant incubator air temperature. Trial methodologic quality was systematically assessed. Outcome measures included death, timing of death, cause of death, and other clinical outcomes. Categorical outcomes were analyzed using relative risk and risk difference. Meta-analysis assumed a fixed effect model. Compared to setting a constant incubator air temperature of 31.8C, servo-control of abdominal skin temperature at 36C reduces the neonatal death rate among low birth weight infants: relative risk 0.72 (95% CI 0.54, 0.97); risk difference -12.7% (95% CI -1.6, -23.9). This effect is even greater among VLBW infants. During at least the first week after birth, low birth weight babies should be provided with a carefully regulated thermal environment that is near the thermoneutral point. For LBW babies in incubators, this can be achieved by adjusting incubator temperature to maintain an anterior abdominal skin temperature of at least 36C, using either servo-control or frequent manual adjustment of incubator air temperature.

Data Assimilation Experiments using Quality Controlled AIRS Version 5 Temperature Soundings

NASA Technical Reports Server (NTRS)

SUsskind, Joel

2008-01-01

The AIRS Science Team Version 5 retrieval algorithm has been finalized and is now operational at the Goddard DAAC in the processing (and reprocessing) of all AIRS data. The AIRS Science Team Version 5 retrieval algorithm contains two significant improvements over Version 4: 1) Improved physics allows for use of AIRS observations in the entire 4.3 pm C02 absorption band in the retrieval of temperature profile T(p) during both day and night. Tropospheric sounding 15 pm C02 observations are now used primarily in the generation of cloud cleared radiances Ri. This approach allows for the generation of accurate values of Ri and T(p) under most cloud conditions. 2) Another very significant improvement in Version 5 is the ability to generate accurate case-by-case, level-by-level error estimates for the atmospheric temperature profile, as well as for channel-by- channel error estimates for Ri. These error estimates are used for quality control of the retrieved products. We have conducted forecast impact experiments assimilating AIRS temperature profiles with different levels of quality control using the NASA GEOS-5 data assimilation system. Assimilation of quality controlled T(p) resulted in significantly improved forecast skill compared to that obtained from analyses obtained when all data used operationally by NCEP, except for AIRS data, is assimilated. We also conducted an experiment assimilating AIRS radiances uncontaminated by clouds, as done Operationally by ECMWF and NCEP. Forecasts resulting from assimilated AIRS radiances were of poorer quality than those obtained assimilating AIRS temperatures.

Possible Economies in Air-Conditioning by Accepting Temperature Swings.

ERIC Educational Resources Information Center

Loudon, A. G.; Petherbridge, P.

Public building air conditioning systems, which use constant and varying heat and cooling loads, are compared and investigated. Experiments indicated that constant temperature controls based on outside air temperature alone were inefficient. Ventilating a building with outside air and the methods of doing so are cited as being the most economical…

Experimental Investigation of a Temperature-Controlled Car Seat Powered by an Exhaust Thermoelectric Generator

NASA Astrophysics Data System (ADS)

Du, H.; Wang, Y. P.; Yuan, X. H.; Deng, Y. D.; Su, C. Q.

2016-03-01

To improve the riding comfort and rational utilization of the electrical energy captured by an automotive thermoelectric generator (ATEG), a temperature-controlled car seat was constructed to adjust the temperature of the car seat surface. Powered by the ATEG and the battery, the seat-embedded air conditioner can improve the riding comfort using a thermoelectric device to adjust the surface temperature of the seat, with an air duct to regulate the cold side and hot side of the thermoelectric device. The performance of the thermoelectric cooler (TEC) and theoretical analysis on the optimum state of the TEC device are put forward. To verify the rationality of the air duct design and to ensure sufficient air supply, the velocity field of the air duct system was obtained by means of the finite element method. To validate the reliability of the numerical simulation, the air velocity around the thermoelectric device was measured by a wind speed transmitter. The performance of the temperature-controlled car seat has been validated and is in good agreement with bench tests and real vehicle tests.

Servo-control for maintaining abdominal skin temperature at 36C in low birth weight infants.

PubMed

Sinclair, J C

2002-01-01

Randomized trials have shown that the neonatal mortality rate of low birth-weight babies can be reduced by keeping them warm. For low birth-weight babies nursed in incubators, warm conditions may be achieved either by heating the air to a desired temperature, or by servo-controlling the baby's body temperature at a desired set-point. In low birth weight infants, to determine the effect on death and other important clinical outcomes of targeting body temperature rather than air temperature as the end-point of control of incubator heating. Standard search strategy of the Cochrane Neonatal Review Group. Searches were made of the Cochrane Controlled Trials Register (CCTR) (Cochrane Library, Issue 4, 2001) and MEDLINE, 1966 to November 2001. Randomized or quasi-randomized trials which test the effects of having the heat output of the incubator servo-controlled from body temperature compared with setting a constant incubator air temperature. Trial methodologic quality was systematically assessed. Outcome measures included death, timing of death, cause of death, and other clinical outcomes. Categorical outcomes were analyzed using relative risk and risk difference. Meta-analysis assumed a fixed effect model. Two eligible trials were found. In total, they included 283 babies and 112 deaths. Compared to setting a constant incubator air temperature of 31.8C, servo-control of abdominal skin temperature at 36C reduces the neonatal death rate among low birth weight infants: relative risk 0.72 (95% CI 0.54, 0.97); risk difference -12.7% (95% CI -1.6, -23.9). This effect is even greater among VLBW infants. During at least the first week after birth, low birth weight babies should be provided with a carefully regulated thermal environment that is near the thermoneutral point. For LBW babies in incubators, this can be achieved by adjusting incubator temperature to maintain an anterior abdominal skin temperature of at least 36C, using either servo-control or frequent manual adjustment of incubator air temperature.

Improving Forecast Skill by Assimilation of Quality Controlled AIRS Version 5 Temperature Soundings

NASA Technical Reports Server (NTRS)

Susskind, Joel; Reale, Oreste

2009-01-01

The AIRS Science Team Version 5 retrieval algorithm has been finalized and is now operational at the Goddard DAAC in the processing (and reprocessing) of all AIRS data. The AIRS Science Team Version 5 retrieval algorithm contains two significant improvements over Version 4: 1) Improved physics allows for use of AIRS observations in the entire 4.3 micron CO2 absorption band in the retrieval of temperature profile T(p) during both day and night. Tropospheric sounding 15 micron CO2 observations are now used primarily in the generation of cloud cleared radiances R(sub i). This approach allows for the generation of accurate values of R(sub i) and T(p) under most cloud conditions. 2) Another very significant improvement in Version 5 is the ability to generate accurate case-by-case, level-by-level error estimates for the atmospheric temperature profile, as well as for channel-by-channel error estimates for R(sub i). These error estimates are used for Quality Control of the retrieved products. We have conducted forecast impact experiments assimilating AIRS temperature profiles with different levels of Quality Control using the NASA GEOS-5 data assimilation system. Assimilation of Quality Controlled T(p) resulted in significantly improved forecast skill compared to that obtained from analyses obtained when all data used operationally by NCEP, except for AIRS data, is assimilated. We also conducted an experiment assimilating AIRS radiances uncontaminated by clouds, as done operationally by ECMWF and NCEP. Forecast resulting from assimilated AIRS radiances were of poorer quality than those obtained assimilating AIRS temperatures.

Thermal comfort, perceived air quality, and cognitive performance when personally controlled air movement is used by tropically acclimatized persons.

PubMed

Schiavon, S; Yang, B; Donner, Y; Chang, V W-C; Nazaroff, W W

2017-05-01

In a warm and humid climate, increasing the temperature set point offers considerable energy benefits with low first costs. Elevated air movement generated by a personally controlled fan can compensate for the negative effects caused by an increased temperature set point. Fifty-six tropically acclimatized persons in common Singaporean office attire (0.7 clo) were exposed for 90 minutes to each of five conditions: 23, 26, and 29°C and in the latter two cases with and without occupant-controlled air movement. Relative humidity was maintained at 60%. We tested thermal comfort, perceived air quality, sick building syndrome symptoms, and cognitive performance. We found that thermal comfort, perceived air quality, and sick building syndrome symptoms are equal or better at 26°C and 29°C than at the common set point of 23°C if a personally controlled fan is available for use. The best cognitive performance (as indicated by task speed) was obtained at 26°C; at 29°C, the availability of an occupant-controlled fan partially mitigated the negative effect of the elevated temperature. The typical Singaporean indoor air temperature set point of 23°C yielded the lowest cognitive performance. An elevated set point in air-conditioned buildings augmented with personally controlled fans might yield benefits for reduced energy use and improved indoor environmental quality in tropical climates. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Preterm infant thermal responses to caregiving differ by incubator control mode.

PubMed

Thomas, Karen A

2003-12-01

To determine the influence of caregiving on preterm infant and incubator temperature and to investigate incubator control mode in thermal responses to caregiving. The intensive within-subject design involved continuous recording of infant and incubator temperature and videotaping throughout a 24-hour period in 40 hospitalized preterm infants. Temperature at care onset was compared with care offset, and 5, 10, 15, and 20 minutes following care offset using ANOVA-RM. Following caregiving, infant and incubator temperature differed significantly over time by incubator control mode. In air servo-control, infant temperature tended to decrease after caregiving, while in skin servo-control infant temperature remained relatively stable. With caregiving, incubator temperature remained consistent in air servo-control and increased in skin servo-control. The temperature effects of caregiving should be considered relative to maintenance of thermoneutrality and unintentional thermal stimulation.

Verification of Energy Reduction Effect through Control Optimization of Supply Air Temperature in VRF-OAP System

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

Lee, Je; Yoon, Hyun; Im, Piljae

This paper developed an algorithm that controls the supply air temperature in the variable refrigerant flow (VRF), outdoor air processing unit (OAP) system, according to indoor and outdoor temperature and humidity, and verified the effects after applying the algorithm to real buildings. The VRF-OAP system refers to a heating, ventilation, and air conditioning (HVAC) system to complement a ventilation function, which is not provided in the VRF system. It is a system that supplies air indoors by heat treatment of outdoor air through the OAP, as a number of indoor units and OAPs are connected to the outdoor unit inmore » the VRF system simultaneously. This paper conducted experiments with regard to changes in efficiency and the cooling capabilities of each unit and system according to supply air temperature in the OAP using a multicalorimeter. Based on these results, an algorithm that controlled the temperature of the supply air in the OAP was developed considering indoor and outdoor temperatures and humidity. The algorithm was applied in the test building to verify the effects of energy reduction and the effects on indoor temperature and humidity. Loads were then changed by adjusting the number of conditioned rooms to verify the effect of the algorithm according to various load conditions. In the field test results, the energy reduction effect was approximately 15–17% at a 100% load, and 4–20% at a 75% load. However, no significant effects were shown at a 50% load. The indoor temperature and humidity reached a comfortable level.« less

Verification of Energy Reduction Effect through Control Optimization of Supply Air Temperature in VRF-OAP System

DOE PAGES

Lee, Je; Yoon, Hyun; Im, Piljae; ...

2017-12-27

This paper developed an algorithm that controls the supply air temperature in the variable refrigerant flow (VRF), outdoor air processing unit (OAP) system, according to indoor and outdoor temperature and humidity, and verified the effects after applying the algorithm to real buildings. The VRF-OAP system refers to a heating, ventilation, and air conditioning (HVAC) system to complement a ventilation function, which is not provided in the VRF system. It is a system that supplies air indoors by heat treatment of outdoor air through the OAP, as a number of indoor units and OAPs are connected to the outdoor unit inmore » the VRF system simultaneously. This paper conducted experiments with regard to changes in efficiency and the cooling capabilities of each unit and system according to supply air temperature in the OAP using a multicalorimeter. Based on these results, an algorithm that controlled the temperature of the supply air in the OAP was developed considering indoor and outdoor temperatures and humidity. The algorithm was applied in the test building to verify the effects of energy reduction and the effects on indoor temperature and humidity. Loads were then changed by adjusting the number of conditioned rooms to verify the effect of the algorithm according to various load conditions. In the field test results, the energy reduction effect was approximately 15–17% at a 100% load, and 4–20% at a 75% load. However, no significant effects were shown at a 50% load. The indoor temperature and humidity reached a comfortable level.« less

Advances in thermal control and performance of the MMT M1 mirror

NASA Astrophysics Data System (ADS)

Gibson, J. D.; Williams, G. G.; Callahan, S.; Comisso, B.; Ortiz, R.; Williams, J. T.

2010-07-01

Strategies for thermal control of the 6.5-meter diameter borosilicate honeycomb primary (M1) mirror at the MMT Observatory have included: 1) direct control of ventilation system chiller setpoints by the telescope operator, 2) semiautomated control of chiller setpoints, using a fixed offset from the ambient temperature, and 3) most recently, an automated temperature controller for conditioned air. Details of this automated controller, including the integration of multiple chillers, heat exchangers, and temperature/dew point sensors, are presented here. Constraints and sanity checks for thermal control are also discussed, including: 1) mirror and hardware safety, 2) aluminum coating preservation, and 3) optimization of M1 thermal conditions for science acquisition by minimizing both air-to-glass temperature differences, which cause mirror seeing, and internal glass temperature gradients, which cause wavefront errors. Consideration is given to special operating conditions, such as high dew and frost points. Precise temperature control of conditioned ventilation air as delivered to the M1 mirror cell is also discussed. The performance of the new automated controller is assessed and compared to previous control strategies. Finally, suggestions are made for further refinement of the M1 mirror thermal control system and related algorithms.

Research on the operation control strategy of the cooling ceiling combined with fresh air system

NASA Astrophysics Data System (ADS)

Huang, Tao; Li, Hao

2018-03-01

The cooling ceiling combined with independent fresh air system was built by TRNSYS. And the cooling effects of the air conditioning system of an office in Beijing in a summer typical day were simulated. Based on the “variable temperature” control strategy, the operation strategy of “variable air volume auxiliary adjustment” was put forward. The variation of the indoor temperature, the indoor humidity, the temperature of supplying water and the temperature of returning water were simulated under the two control strategies. The energy consumption of system during the whole summer was compared by utilizing the two control strategies, and the indoor thermal comfort was analyzed. The optimal control strategy was proposed under the condition that the condensation on the surface of the cooling ceiling is not occurred and the indoor thermal comfort is satisfied.

Data Assimilation Experiments Using Quality Controlled AIRS Version 5 Temperature Soundings

NASA Technical Reports Server (NTRS)

Susskind, Joel

2009-01-01

The AIRS Science Team Version 5 retrieval algorithm has been finalized and is now operational at the Goddard DAAC in the processing (and reprocessing) of all AIRS data. The AIRS Science Team Version 5 retrieval algorithm contains a number of significant improvements over Version 4. Two very significant improvements are described briefly below. 1) The AIRS Science Team Radiative Transfer Algorithm (RTA) has now been upgraded to accurately account for effects of non-local thermodynamic equilibrium on the AIRS observations. This allows for use of AIRS observations in the entire 4.3 micron CO2 absorption band in the retrieval algorithm during both day and night. Following theoretical considerations, tropospheric temperature profile information is obtained almost exclusively from clear column radiances in the 4.3 micron CO2 band in the AIRS Version 5 temperature profile retrieval step. These clear column radiances are a derived product that are indicative of radiances AIRS channels would have seen if the field of view were completely clear. Clear column radiances for all channels are determined using tropospheric sounding 15 micron CO2 observations. This approach allows for the generation of accurate values of clear column radiances and T(p) under most cloud conditions. 2) Another very significant improvement in Version 5 is the ability to generate accurate case-by-case, level-by-level error estimates for the atmospheric temperature profile, as well as for channel-by-channel clear column radiances. These error estimates are used for quality control of the retrieved products. Based on error estimate thresholds, each temperature profiles is assigned a characteristic pressure, pg, down to which the profile is characterized as good for use for data assimilation purposes. We have conducted forecast impact experiments assimilating AIRS quality controlled temperature profiles using the NASA GEOS-5 data assimilation system, consisting of the NCEP GSI analysis coupled with the NASA FVGCM, at a spatial resolution of 0.5 deg by 0.5 deg. Assimilation of Quality Controlled AIRS temperature profiles down to pg resulted in significantly improved forecast skill compared to that obtained from experiments when all data used operationally by NCEP, except for AIRS data, is assimilated. These forecasts were also significantly better than to those obtained when AIRS radiances (rather than temperature profiles) are assimilated, which is the way AIRS data is used operationally by NCEP and ECMWF.

Application of Multivariable Model Predictive Advanced Control for a 2×310T/H CFB Boiler Unit

NASA Astrophysics Data System (ADS)

Weijie, Zhao; Zongllao, Dai; Rong, Gou; Wengan, Gong

When a CFB boiler is in automatic control, there are strong interactions between various process variables and inverse response characteristics of bed temperature control target. Conventional Pill control strategy cannot deliver satisfactory control demand. Kalman wave filter technology is used to establish a non-linear combustion model, based on the CFB combustion characteristics of bed fuel inventory, heating values, bed lime inventory and consumption. CFB advanced combustion control utilizes multivariable model predictive control technology to optimize primary and secondary air flow, bed temperature, air flow, fuel flow and heat flux. In addition to providing advanced combustion control to 2×310t/h CFB+1×100MW extraction condensing turbine generator unit, the control also provides load allocation optimization and advanced control for main steam pressure, combustion and temperature. After the successful implementation, under 10% load change, main steam pressure varied less than ±0.07MPa, temperature less than ±1°C, bed temperature less than ±4°C, and air flow (O2) less than ±0.4%.

Corrosion detector apparatus for universal assessment of pollution in data centers

DOEpatents

Hamann, Hendrik F.; Klein, Levente I.

2015-08-18

A compact corrosion measurement apparatus and system includes an air fan, a corrosion sensor, a temperature sensor, a humidity sensor, a heater element, and an air flow sensor all under control to monitor and maintain constant air parameters in an environment and minimize environmental fluctuations around the corrosion sensor to overcome the variation commonly encountered in corrosion rate measurement. The corrosion measurement apparatus includes a structure providing an enclosure within which are located the sensors. Constant air flow and temperature is maintained within the enclosure where the corrosion sensor is located by integrating a variable speed air fan and a heater with the corresponding feedback loop control. Temperature and air flow control loops ensure that corrosivity is measured under similar conditions in different facilities offering a general reference point that allow a one to one comparison between facilities with similar or different pollution levels.

Water reuse systems: A review of the principal components

USGS Publications Warehouse

Lucchetti, G.; Gray, G.A.

1988-01-01

Principal components of water reuse systems include ammonia removal, disease control, temperature control, aeration, and particulate filtration. Effective ammonia removal techniques include air stripping, ion exchange, and biofiltration. Selection of a particular technique largely depends on site-specific requirements (e.g., space, existing water quality, and fish densities). Disease control, although often overlooked, is a major problem in reuse systems. Pathogens can be controlled most effectively with ultraviolet radiation, ozone, or chlorine. Simple and inexpensive methods are available to increase oxygen concentration and eliminate gas supersaturation, these include commercial aerators, air injectors, and packed columns. Temperature control is a major advantage of reuse systems, but the equipment required can be expensive, particularly if water temperature must be rigidly controlled and ambient air temperature fluctuates. Filtration can be readily accomplished with a hydrocyclone or sand filter that increases overall system efficiency. Based on criteria of adaptability, efficiency, and reasonable cost, we recommend components for a small water reuse system.

Optimal fault-tolerant control strategy of a solid oxide fuel cell system

NASA Astrophysics Data System (ADS)

Wu, Xiaojuan; Gao, Danhui

2017-10-01

For solid oxide fuel cell (SOFC) development, load tracking, heat management, air excess ratio constraint, high efficiency, low cost and fault diagnosis are six key issues. However, no literature studies the control techniques combining optimization and fault diagnosis for the SOFC system. An optimal fault-tolerant control strategy is presented in this paper, which involves four parts: a fault diagnosis module, a switching module, two backup optimizers and a controller loop. The fault diagnosis part is presented to identify the SOFC current fault type, and the switching module is used to select the appropriate backup optimizer based on the diagnosis result. NSGA-II and TOPSIS are employed to design the two backup optimizers under normal and air compressor fault states. PID algorithm is proposed to design the control loop, which includes a power tracking controller, an anode inlet temperature controller, a cathode inlet temperature controller and an air excess ratio controller. The simulation results show the proposed optimal fault-tolerant control method can track the power, temperature and air excess ratio at the desired values, simultaneously achieving the maximum efficiency and the minimum unit cost in the case of SOFC normal and even in the air compressor fault.

Off-design performance of a chemical looping combustion (CLC) combined cycle: effects of ambient temperature

NASA Astrophysics Data System (ADS)

Chi, Jinling; Wang, Bo; Zhang, Shijie; Xiao, Yunhan

2010-02-01

The present work investigates the influence of ambient temperature on the steady-state off-design thermodynamic performance of a chemical looping combustion (CLC) combined cycle. A sensitivity analysis of the CLC reactor system was conducted, which shows that the parameters that influence the temperatures of the CLC reactors most are the flow rate and temperature of air entering the air reactor. For the ambient temperature variation, three off-design control strategies have been assumed and compared: 1) without any Inlet Guide Vane (IGV) control, 2) IGV control to maintain air reactor temperature and 3) IGV control to maintain constant fuel reactor temperature, aside from fuel flow rate adjusting. Results indicate that, compared with the conventional combined cycle, due to the requirement of pressure balance at outlet of the two CLC reactors, CLC combined cycle shows completely different off-design thermodynamic characteristics regardless of the control strategy adopted. For the first control strategy, temperatures of the two CLC reactors both rise obviously as ambient temperature increases. IGV control adopted by the second and the third strategy has the effect to maintain one of the two reactors' temperatures at design condition when ambient temperature is above design point. Compare with the second strategy, the third would induce more severe decrease of efficiency and output power of the CLC combined cycle.

Smart sensors enable smart air conditioning control.

PubMed

Cheng, Chin-Chi; Lee, Dasheng

2014-06-24

In this study, mobile phones, wearable devices, temperature and human motion detectors are integrated as smart sensors for enabling smart air conditioning control. Smart sensors obtain feedback, especially occupants' information, from mobile phones and wearable devices placed on human body. The information can be used to adjust air conditioners in advance according to humans' intentions, in so-called intention causing control. Experimental results show that the indoor temperature can be controlled accurately with errors of less than ±0.1 °C. Rapid cool down can be achieved within 2 min to the optimized indoor capacity after occupants enter a room. It's also noted that within two-hour operation the total compressor output of the smart air conditioner is 48.4% less than that of the one using On-Off control. The smart air conditioner with wearable devices could detect the human temperature and activity during sleep to determine the sleeping state and adjusting the sleeping function flexibly. The sleeping function optimized by the smart air conditioner with wearable devices could reduce the energy consumption up to 46.9% and keep the human health. The presented smart air conditioner could provide a comfortable environment and achieve the goals of energy conservation and environmental protection.

Smart Sensors Enable Smart Air Conditioning Control

PubMed Central

Cheng, Chin-Chi; Lee, Dasheng

2014-01-01

In this study, mobile phones, wearable devices, temperature and human motion detectors are integrated as smart sensors for enabling smart air conditioning control. Smart sensors obtain feedback, especially occupants' information, from mobile phones and wearable devices placed on human body. The information can be used to adjust air conditioners in advance according to humans' intentions, in so-called intention causing control. Experimental results show that the indoor temperature can be controlled accurately with errors of less than ±0.1 °C. Rapid cool down can be achieved within 2 min to the optimized indoor capacity after occupants enter a room. It's also noted that within two-hour operation the total compressor output of the smart air conditioner is 48.4% less than that of the one using On-Off control. The smart air conditioner with wearable devices could detect the human temperature and activity during sleep to determine the sleeping state and adjusting the sleeping function flexibly. The sleeping function optimized by the smart air conditioner with wearable devices could reduce the energy consumption up to 46.9% and keep the human health. The presented smart air conditioner could provide a comfortable environment and achieve the goals of energy conservation and environmental protection. PMID:24961213

Influence of harvest residues and vegetation on microsite soil and air temperatures in a young conifer plantation.

Treesearch

W.D. Devine; C.A. Harrington

2007-01-01

This study examines the effects of bole-only harvesting with and without vegetation control (BO+VC; BO-VC) and total-tree harvesting plus removal of legacy woody debris with vegetation control (TTP+VC) on microsite soil and air temperatures in a young Douglas-fir plantation. Mean soil temperature and the diurnal range in soil temperature during the growing season...

U. S. (United States) Air Force Fuel Cell Application Analysis.

DTIC Science & Technology

1982-01-01

Desulfurizer and shift cata- lyst temperatures are maintained by controlling the amount of gas entering or by-passing the external water vaporizer. If...rich gas . The sul- fur content of the desulfurized fuel gas must be less than 1 ppm. Reforming takes place in a nickel catalyst bed, operating at... Control Supplemental Firing Fuel Cell Temperature Recirculation Air Temperature Control via Cooler Fan Speed Exhaust Gas Water Load Following damper

Fuzzy logic control of rotating drum bioreactor for improved production of amylase and protease enzymes by Aspergillus oryzae in solid-state fermentation.

PubMed

Sukumprasertsri, Monton; Unrean, Pornkamol; Pimsamarn, Jindarat; Kitsubun, Panit; Tongta, Anan

2013-03-01

In this study, we compared the performance of two control systems, fuzzy logic control (FLC) and conventional control (CC). The control systems were applied for controlling temperature and substrate moisture content in a solidstate fermentation for the biosynthesis of amylase and protease enzymes by Aspergillus oryzae. The fermentation process was achieved in a 200 L rotating drum bioreactor. Three factors affecting temperature and moisture content in the solid-state fermentation were considered. They were inlet air velocity, speed of the rotating drum bioreactor, and spray water addition. The fuzzy logic control system was designed using four input variables: air velocity, substrate temperature, fermentation time, and rotation speed. The temperature was controlled by two variables, inlet air velocity and rotational speed of bioreactor, while the moisture content was controlled by spray water. Experimental results confirmed that the FLC system could effectively control the temperature and moisture content of substrate better than the CC system, resulting in an increased enzyme production by A. oryzae. Thus, the fuzzy logic control is a promising control system that can be applied for enhanced production of enzymes in solidstate fermentation.

Toward the Active Control of Heat Transfer in the Hot Gas Path of Gas Turbines

NASA Technical Reports Server (NTRS)

Oertling, Jeremiah E.

2003-01-01

The work at NASA this summer has focused on assisting the Professor's project, namely "Toward the Active Control of Heat Transfer in the Hot Gas Path of Gas Turbines." The mode of controlling the Heat Transfer that the project focuses on is film cooling. Film cooling is used in high temperature regions of a gas turbine and extends the life of the components exposed to these extreme temperatures. A "cool" jet of air is injected along the surface of the blade and this layer of cool air shields the blade from the high temperatures. Cool is a relative term. The hot gas path temperatures reach on the order of 1500 to 2000 K. The "coo" air is on the order of 700 to 1000 K. This cooler air is bled off of an appropriate compressor stage. The next parameter of interest is the jet s position and orientation in the flow-field.

Air temperature recordings in infant incubators.

PubMed Central

Aynsley-Green, A; Roberton, N R; Rolfe, P

1975-01-01

Air temperatures were continuously recorded inside four incubators with proportional heating control and six incubators with on/off heating cycles, during routine use. The air temperatures in the former were constant throughout, with a gradient between the roof and above-mattress air temperature not exceeding 1 degree C. In contrast, the recordings from the latter models showed a regular cyclical oscillation, the duration of the cycle varying from 14 to 44 minutes. Each incubator had a characteristic profile. The roof air temperature could vary by as much as 7-1 degrees C and the above-mattress air temperature by as much as 2-6 degrees C during the cycle. The oscillation persisted in the air temperatures recorded inside an open-ended hemicylindrical heat shield when used inside these incubators, but was markedly reduced inside a closed-ended heat shield, Carbon dioxide concentration did not increase significantly inside the latter. Images FIG. 1 FIG. 2 PMID:1147654

Variability of Winter Air Temperature in Mid-Latitude Europe

NASA Technical Reports Server (NTRS)

Otterman, J.; Ardizzone, J.; Atlas, R.; Bungato, D.; Cierniewski, J.; Jusem, J. C.; Przybylak, R.; Schubert, S.; Starr, D.; Walczewski, J.

2002-01-01

The aim of this paper is to report extreme winter/early-spring air temperature (hereinafter temperature) anomalies in mid-latitude Europe, and to discuss the underlying forcing to these interannual fluctuations. Warm advection from the North Atlantic in late winter controls the surface-air temperature, as indicated by the substantial correlation between the speed of the surface southwesterlies over the eastern North Atlantic (quantified by a specific Index Ina) and the 2-meter level air temperatures (hereinafter Ts) over Europe, 45-60 deg N, in winter. In mid-March and subsequently, the correlation drops drastically (quite often it is negative). This change in the relationship between Ts and Ina marks a transition in the control of the surface-air temperature: absorption of insolation replaces the warm advection as the dominant control. This forcing by maritime-air advection in winter was demonstrated in a previous publication, and is re-examined here in conjunction with extreme fluctuations of temperatures in Europe. We analyze here the interannual variability at its extreme by comparing warm-winter/early-spring of 1989/90 with the opposite scenario in 1995/96. For these two December-to-March periods the differences in the monthly mean temperature in Warsaw and Torun, Poland, range above 10 C. Short-term (shorter than a month) fluctuations of the temperature are likewise very strong. We conduct pentad-by-pentad analysis of the surface-maximum air temperature (hereinafter Tmax), in a selected location, examining the dependence on Ina. The increased cloudiness and higher amounts of total precipitable water, corollary effects to the warm low-level advection. in the 1989/90 winter, enhance the positive temperature anomalies. The analysis of the ocean surface winds is based on the Special Sensor Microwave/Imager (SSM/I) dataset; ascent rates, and over land wind data are from the European Centre for Medium-Range Weather Forecasts (ECMWF); maps of 2-m temperature, cloud cover and precipitable water are from the National Centers for Environmental Prediction (NCEP) Reanalysis.

Environmental Control and Life Support Systems

NASA Technical Reports Server (NTRS)

Engel, Joshua Allen

2017-01-01

The Environmental Control System provides a controlled air purge to Orion and SLS. The ECS performs this function by processing 100% ambient air while simultaneously controlling temperature, pressure, humidity, cleanliness and purge distribution.

Spatial and seasonal characteristics of cold-air pools in the upper Zêzere valley (Serra da Estrela, Portugal)

NASA Astrophysics Data System (ADS)

Mora, Carla

2010-05-01

Occurrence, formation, spatial patterns and intensity of cold air pools/lakes were studied in the Serra da Estrela (40° 20'N 7° 35'W, 1993m, Central Portugal) from January to December 2000. Data was collected using a network of air temperature dataloggers installed at different topographic positions (interfluves, valley floors and slopes) recording at 2-h intervals. A k-means classification was applied to the dataset of instantaneous air temperatures, and 3 types of thermal patterns were identified. Type 1 (66% cases) shows events with decreasing air temperatures with altitude. Type 2 (27% cases) shows accumulation of cold air in the valleys with higher valley floors showing the lowest temperatures. Type 3 (7% cases) show accumulation of cold air, but with lowest air temperatures in the valleys at lower altitudes. Causal factors for the occurrence of the patterns were studied by applying discriminant analysis on meteorological and topographical variables. Type 1 occurs under atmospheric instability conditions, while types 2 and 3 relate to atmospheric stability. Types 2 and 3 are controlled by seasonality and local insolation/shadowing effects. For the detailed study of cold air accumulations, two approaches were followed: the analysis of temperature differences between a station in a crest and a station in a glacial cirque floor; and, the analysis of 5-min interval temperature data along a transect in the Zêzere valley.The differences in air temperature between the glacier cirque floor (Covão Cimeiro, 1620m) and the crest (Cântaro Gordo, 1870m) were classified into 9 types of regime. Thermal inversions in the cirque were found in 6 types (48%). These are characterized in detail and the geographical and meteorological controlling factors are analyzed using one-way ANOVA and discriminant analysis. The 6 types show different daily regimes and inversion intensities, as well as a seasonal trend. The maximum inversion intensity was 9 °C, and the minimum temperature -17 °C at the cirque floor. Simultaneoulsy, the ridge showed -9 °C. Thermal inversions show atmospheric stability with low wind speed and low cloudiness. The sequence of patterns throughout the year is controlled by topographic factors and insolation at the cirque floor. The formation of thermal inversions in a NNE-SSW direction valley (Zêzere valley), their durationand dissipation were studied in detail during 5 days of atmospheric stability using air temperature recorded at 5-min intervals. During the day, air temperature decreased with altitude (-0.7 °C/100m to -1 °C/100m), and during the night, the valley floor showed lower temperatures than the mountain summit. During the night a thermal belt formed and the valley floor was 3 °C colder than the top of the inversion layer. During the day there was an asymmetry in the distribution of temperatures along the valley controlled by solar radiation. Air temperatures ranged from -5 °C to 16 °C. The results show the effect of topography on air temperatures in situations of atmospheric stability and can be extrapolated to the mountains with similar climatic and topographic conditions. The identification of the shadowing effect induced by valleys and its impact on the maintenance of cold air lakes during the morning in the valleys of North-South orientation can be of special interest for planning and environmental impact studies.

Regulation and Measurement of the Heat Generated by Automatic Tooth Preparation in a Confined Space.

PubMed

Yuan, Fusong; Zheng, Jianqiao; Sun, Yuchun; Wang, Yong; Lyu, Peijun

2017-06-01

The aim of this study was to assess and regulate heat generation in the dental pulp cavity and circumambient temperature around a tooth during laser ablation with a femtosecond laser in a confined space. The automatic tooth preparing technique is one of the traditional oral clinical technology innovations. In this technique, a robot controlled an ultrashort pulse laser to automatically complete the three-dimensional teeth preparing in a confined space. The temperature control is the main measure for protecting the tooth nerve. Ten tooth specimens were irradiated with a femtosecond laser controlled by a robot in a confined space to generate 10 teeth preparation. During the process, four thermocouple sensors were used to record the pulp cavity and circumambient environment temperatures with or without air cooling. A statistical analysis of the temperatures was performed between the conditions with and without air cooling (p < 0.05). The recordings showed that the temperature with air cooling was lower than that without air cooling and that the heat generated in the pulp cavity was lower than the threshold for dental pulp damage. These results indicate that femtosecond laser ablation with air cooling might be an appropriate method for automatic tooth preparing.

Composting on Mars or the Moon: II. Temperature feedback control with top-wise introduction of waste material and air

NASA Technical Reports Server (NTRS)

Finstein, M. S.; Hogan, J. A.; Sager, J. C.; Cowan, R. M.; Strom, P. F.; Janes, H. W. (Principal Investigator)

1999-01-01

Whereas Earth-based composting reactors that effectively control the process are batch operations with bottom-to-top airflow, in extraterrestrial application both the fresh waste and the air need to be introduced from above. Stabilized compost and used air would exit below. This materials flow pattern permits the addition of waste whenever generated, obviating the need for multiple reactors, and the incorporation of a commode in the lid. Top loading in turn dictates top-down aeration, so that the most actively decomposing material (greatest need for heat removal and O2 replenishment) is first encountered. This novel material and aeration pattern was tested in conjunction with temperature feedback process control. Reactor characteristics were: working, volume, 0.15 m3; charge, 2 kg dry biomass per day (comparable to a 3-4 person self-sufficient bioregenerative habitat); retention time, 7 days. Judging from temperature profile, O2 level, air usage, pressure head loss, moisture, and odor, the system was effectively controlled over a 35-day period. Dry matter disappearance averaged 25% (10-42%). The compost product was substantially, though not completely, stabilized. This demonstrates the compatibility of top-wise introduction of waste and air with temperature feedback process control.

Composting on Mars or the Moon: II. Temperature feedback control with top-wise introduction of waste material and air.

PubMed

Finstein, M S; Hogan, J A; Sager, J C; Cowan, R M; Strom, P F

1999-01-01

Whereas Earth-based composting reactors that effectively control the process are batch operations with bottom-to-top airflow, in extraterrestrial application both the fresh waste and the air need to be introduced from above. Stabilized compost and used air would exit below. This materials flow pattern permits the addition of waste whenever generated, obviating the need for multiple reactors, and the incorporation of a commode in the lid. Top loading in turn dictates top-down aeration, so that the most actively decomposing material (greatest need for heat removal and O2 replenishment) is first encountered. This novel material and aeration pattern was tested in conjunction with temperature feedback process control. Reactor characteristics were: working, volume, 0.15 m3; charge, 2 kg dry biomass per day (comparable to a 3-4 person self-sufficient bioregenerative habitat); retention time, 7 days. Judging from temperature profile, O2 level, air usage, pressure head loss, moisture, and odor, the system was effectively controlled over a 35-day period. Dry matter disappearance averaged 25% (10-42%). The compost product was substantially, though not completely, stabilized. This demonstrates the compatibility of top-wise introduction of waste and air with temperature feedback process control.

Interactive short-term effects of equivalent temperature and air pollution on human mortality in Berlin and Lisbon.

PubMed

Burkart, Katrin; Canário, Paulo; Breitner, Susanne; Schneider, Alexandra; Scherber, Katharina; Andrade, Henrique; Alcoforado, Maria João; Endlicher, Wilfried

2013-12-01

There is substantial evidence that both temperature and air pollution are predictors of mortality. Thus far, few studies have focused on the potential interactive effects between the thermal environment and different measures of air pollution. Such interactions, however, are biologically plausible, as (extreme) temperature or increased air pollution might make individuals more susceptible to the effects of each respective predictor. This study investigated the interactive effects between equivalent temperature and air pollution (ozone and particulate matter) in Berlin (Germany) and Lisbon (Portugal) using different types of Poisson regression models. The findings suggest that interactive effects exist between air pollutants and equivalent temperature. Bivariate response surface models and generalised additive models (GAMs) including interaction terms showed an increased risk of mortality during periods of elevated equivalent temperatures and air pollution. Cold effects were mostly unaffected by air pollution. The study underscores the importance of air pollution control in mitigating heat effects. Copyright © 2013 Elsevier Ltd. All rights reserved.

Control Strategies for Reducing Heating, Ventilating, and Air Conditioning (HVAC) Energy Consumption in Single Buildings.

DTIC Science & Technology

1983-03-01

economizer and enthalpy cycles, scheduled temperature reset, chiller control and chilled water reset, boiler control and hot water temperature reset...temperature reset, chiller control and chilled water reset, boiler control and hot water temperature reset, and condenser water temperature reset. Recent...day-night setback. Day-night setback is the strategy of reducing the heating space temperature setpoint or raising the cooling space temperature

Data Assimilation Experiments using Quality Controlled AIRS Version 5 Temperature Soundings

NASA Technical Reports Server (NTRS)

Susskind, Joel

2008-01-01

The AIRS Science Team Version 5 retrieval algorithm has been finalized and is now operational at the Goddard DAAC in the processing (and reprocessing) of all AlRS data. Version 5 contains accurate case-by-case error estimates for most derived products, which are also used for quality control. We have conducted forecast impact experiments assimilating AlRS quality controlled temperature profiles using the NASA GEOS-5 data assimilation system, consisting of the NCEP GSI analysis coupled with the NASA FVGCM. Assimilation of quality controlled temperature profiles resulted in significantly improved forecast skill in both the Northern Hemisphere and Southern Hemisphere Extra-Tropics, compared to that obtained from analyses obtained when all data used operationally by NCEP except for AlRS data is assimilated. Experiments using different Quality Control thresholds for assimilation of AlRS temperature retrievals showed that a medium quality control threshold performed better than a tighter threshold, which provided better overall sounding accuracy; or a looser threshold, which provided better spatial coverage of accepted soundings. We are conducting more experiments to further optimize this balance of spatial coverage and sounding accuracy from the data assimilation perspective. In all cases, temperature soundings were assimilated well below cloud level in partially cloudy cases. The positive impact of assimilating AlRS derived atmospheric temperatures all but vanished when only AIRS stratospheric temperatures were assimilated. Forecast skill resulting from assimilation of AlRS radiances uncontaminated by clouds, instead of AlRS temperature soundings, was only slightly better than that resulting from assimilation of only stratospheric AlRS temperatures. This reduction in forecast skill is most likely the result of significant loss of tropospheric information when only AIRS radiances unaffected by clouds are used in the data assimilation process.

Improving 7-Day Forecast Skill by Assimilation of Retrieved AIRS Temperature Profiles

NASA Technical Reports Server (NTRS)

Susskind, Joel; Rosenberg, Bob

2016-01-01

We conducted a new set of Data Assimilation Experiments covering the period January 1 to February 29, 2016 using the GEOS-5 DAS. Our experiments assimilate all data used operationally by GMAO (Control) with some modifications. Significant improvement in Global and Southern Hemisphere Extra-tropical 7-day forecast skill was obtained when: We assimilated AIRS Quality Controlled temperature profiles in place of observed AIRS radiances, and also did not assimilate CrISATMS radiances, nor did we assimilate radiosonde temperature profiles or aircraft temperatures. This new methodology did not improve or degrade 7-day Northern Hemispheric Extra-tropical forecast skill. We are conducting experiments aimed at further improving of Northern Hemisphere Extra-tropical forecast skill.

40 CFR Appendix Viii to Part 85 - Vehicle and Engine Parameters and Specifications

Code of Federal Regulations, 2014 CFR

2014-07-01

...) AIR PROGRAMS (CONTINUED) CONTROL OF AIR POLLUTION FROM MOBILE SOURCES Pt. 85, App. VIII Appendix VIII.... Air Inlet System. 1. Temperature control system calibration. IV. Fuel System. 1. General. a. Engine idle speed. b. Engine idle mixture. 2. Carburetion. a. Air-fuel flow calibration. b. Transient...

40 CFR Appendix Viii to Part 85 - Vehicle and Engine Parameters and Specifications

Code of Federal Regulations, 2013 CFR

2013-07-01

...) AIR PROGRAMS (CONTINUED) CONTROL OF AIR POLLUTION FROM MOBILE SOURCES Pt. 85, App. VIII Appendix VIII.... Air Inlet System. 1. Temperature control system calibration. IV. Fuel System. 1. General. a. Engine idle speed. b. Engine idle mixture. 2. Carburetion. a. Air-fuel flow calibration. b. Transient...

40 CFR Appendix Viii to Part 85 - Vehicle and Engine Parameters and Specifications

Code of Federal Regulations, 2012 CFR

2012-07-01

...) AIR PROGRAMS (CONTINUED) CONTROL OF AIR POLLUTION FROM MOBILE SOURCES Pt. 85, App. VIII Appendix VIII.... Air Inlet System. 1. Temperature control system calibration. IV. Fuel System. 1. General. a. Engine idle speed. b. Engine idle mixture. 2. Carburetion. a. Air-fuel flow calibration. b. Transient...

Automatic Incubator-type Temperature Control System for Brain Hypothermia Treatment

NASA Astrophysics Data System (ADS)

Gaohua, Lu; Wakamatsu, Hidetoshi

An automatic air-cooling incubator is proposed to replace the manual water-cooling blanket to control the brain tissue temperature for brain hypothermia treatment. Its feasibility is theoretically discussed as follows: First, an adult patient with the cooling incubator is modeled as a linear dynamical patient-incubator biothermal system. The patient is represented by an 18-compartment structure and described by its state equations. The air-cooling incubator provides almost same cooling effect as the water-cooling blanket, if a light breeze of speed around 3 m/s is circulated in the incubator. Then, in order to control the brain temperature automatically, an adaptive-optimal control algorithm is adopted, while the patient-blanket therapeutic system is considered as a reference model. Finally, the brain temperature of the patient-incubator biothermal system is controlled to follow up the given reference temperature course, in which an adaptive algorithm is confirmed useful for unknown environmental change and/or metabolic rate change of the patient in the incubating system. Thus, the present work ensures the development of the automatic air-cooling incubator for a better temperature regulation of the brain hypothermia treatment in ICU.

[Thermal energy utilization analysis and energy conservation measures of fluidized bed dryer].

PubMed

Xing, Liming; Zhao, Zhengsheng

2012-07-01

To propose measures for enhancing thermal energy utilization by analyzing drying process and operation principle of fluidized bed dryers,in order to guide optimization and upgrade of fluidized bed drying equipment. Through a systematic analysis on drying process and operation principle of fluidized beds,the energy conservation law was adopted to calculate thermal energy of dryers. The thermal energy of fluidized bed dryers is mainly used to make up for thermal consumption of water evaporation (Qw), hot air from outlet equipment (Qe), thermal consumption for heating and drying wet materials (Qm) and heat dissipation to surroundings through hot air pipelines and cyclone separators. Effective measures and major approaches to enhance thermal energy utilization of fluidized bed dryers were to reduce exhaust gas out by the loss of heat Qe, recycle dryer export air quantity of heat, preserve heat for dry towers, hot air pipes and cyclone separators, dehumidify clean air in inlets and reasonably control drying time and air temperature. Such technical parameters such air supply rate, air inlet temperature and humidity, material temperature and outlet temperature and humidity are set and controlled to effectively save energy during the drying process and reduce the production cost.

A Dynamic Neural Network Approach to CBM

DTIC Science & Technology

2011-03-15

high efficiency water cooled heat exchanger positioned on the side of the engine. The air temperature was controlled at the desired set-point by...regulating the inlet water flow in the heat exchanger. The temperature of the cooling water was not regulated. The typical set-point for the air charge...temperature was 127 degF, as used in other durability tests carried out in these facilities. Because the heat exchanger controller was optimized for

Method and apparatus for checking fire detectors

NASA Technical Reports Server (NTRS)

Clawson, G. T. (Inventor)

1974-01-01

A fire detector checking method and device are disclosed for nondestructively verifying the operation of installed fire detectors of the type which operate on the principle of detecting the rate of temperature rise of the ambient air to sound an alarm and/or which sound an alarm when the temperature of the ambient air reaches a preset level. The fire alarm checker uses the principle of effecting a controlled simulated alarm condition to ascertain wheather or not the detector will respond. The checker comprises a hand-held instrument employing a controlled heat source, e.g., an electric lamp having a variable input, for heating at a controlled rate an enclosed mass of air in a first compartment, which air mass is then disposed about the fire detector to be checked. A second compartment of the device houses an electronic circuit to sense and adjust the temperature level and heating rate of the heat source.

Smart Fan Modules And System

DOEpatents

Cipolla, Thomas M.; Kaufman, Richard I.; Mok, Lawrence S.

2003-07-15

A fan module including: two or more individual fans, each fan having an air movement means and a motor engaged with the air movement means for accelerating air entering each of the two or more individual fans; a temperature sensor for sensing a temperature associated with the two or more fans and for outputting a first signal corresponding to the temperature; rotational speed sensor for outputting a second signal corresponding to a rotational speed of each of the two or more fans; and a processor for receiving the first and second signals and controlling the two or more individual fans based on the first and second signals. A fan module including: two or more individual fans, each fan having an air movement means and a motor engaged with the air movement means for accelerating air entering each of the two or more individual fans; a temperature sensor for sensing a temperature associated with the two or more fans and for outputting a first signal corresponding to the temperature; rotational speed sensor for outputting a second signal corresponding to a rotational speed of each of the two or more fans; and a processor for receiving the first and second signals and controlling the two or more individual fans based on the first and second signals.

Identify the dominant variables to predict stream water temperature

NASA Astrophysics Data System (ADS)

Chien, H.; Flagler, J.

2016-12-01

Stream water temperature is a critical variable controlling water quality and the health of aquatic ecosystems. Accurate prediction of water temperature and the assessment of the impacts of environmental variables on water temperature variation are critical for water resources management, particularly in the context of water quality and aquatic ecosystem sustainability. The objective of this study is to measure stream water temperature and air temperature and to examine the importance of streamflow on stream water temperature prediction. The measured stream water temperature and air temperature will be used to test two hypotheses: 1) streamflow is a relatively more important factor than air temperature in regulating water temperature, and 2) by combining air temperature and streamflow data stream water temperature can be more accurately estimated. Water and air temperature data loggers are placed at two USGS stream gauge stations #01362357and #01362370, located in the upper Esopus Creek watershed in Phonecia, NY. The ARIMA (autoregressive integrated moving average) time series model is used to analyze the measured water temperature data, identify the dominant environmental variables, and predict the water temperature with identified dominant variable. The preliminary results show that streamflow is not a significant variable in predicting stream water temperature at both USGS gauge stations. Daily mean air temperature is sufficient to predict stream water temperature at this site scale.

Development of a low-cost mini environment chamber for precision instruments

NASA Astrophysics Data System (ADS)

Feng, Jian; Li, Rui-Jun; He, Ya-Xiong; Fan, Kuang-Chao

2016-01-01

The wavelength of laser interferometer used widely in precision measurement instrument is affected by the refractive index of surrounding air, which depends on the temperature, relative humidity (RH) and air pressure. A low-cost mini chamber based on the natural convection principle with high-precision temperature-controlled and humidity-suppressed is proposed in this paper. The main chamber is built up by acrylic walls supported by aluminum beam column and are tailored according to the required space. A thin layer of vacuum insulation panel (VIP) with an ultralow thermal conductivity coefficient is adhered around the walls so as to prevent heat exchange with room air. A high-precision temperature sensor measuring the temperature near the instrument's measuring point provides a feedback signal to a proportional-integral-derivative (PID) controller. Several thermoelectric coolers uniformly arranged on the ceiling of the chamber to cool the air inside the chamber directly without any air supply system, yielding a vibration-free cooling system. A programmable power supply is used as the driver for the coolers to generate different cooling capacities. The down-flowing cool air and the up-flowing hot air form a natural convection, and the air temperature in the chamber gradually becomes stable and finally reaches the temperature set by the PID controller. Recycled desiccant contained silica gels that have high affinity for water is used as a drying agent. Experimental results show that in about two hours the system's steady state error is 0.003°C on average, and the variation range is less than ± 0.02°C when the set temperature is 20°C, the RH is reduced from 66% to about 48%. This innovative mini chamber has the advantages of low-cost, vibration-free, and low energy-consumption. It can be used for any micro/nanomeasurement instrument and its volume can be customer-designed.

System and method for temperature control in an oxygen transport membrane based reactor

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

Kelly, Sean M.

A system and method for temperature control in an oxygen transport membrane based reactor is provided. The system and method involves introducing a specific quantity of cooling air or trim air in between stages in a multistage oxygen transport membrane based reactor or furnace to maintain generally consistent surface temperatures of the oxygen transport membrane elements and associated reactors. The associated reactors may include reforming reactors, boilers or process gas heaters.

Geographical and Geomorphological Effects on Air Temperatures in the Columbia Basin's Signature Vineyards

NASA Astrophysics Data System (ADS)

Olson, L.; Pogue, K. R.; Bader, N.

2012-12-01

The Columbia Basin of Washington and Oregon is one of the most productive grape-growing areas in the United States. Wines produced in this region are influenced by their terroir - the amalgamation of physical and cultural elements that influence grapes grown at a particular vineyard site. Of the physical factors, climate, and in particular air temperature, has been recognized as a primary influence on viticulture. Air temperature directly affects ripening in the grapes. Proper fruit ripening, which requires precise and balanced levels of acid and sugar, and the accumulation of pigment in the grape skin, directly correlates with the quality of wine produced. Many features control air temperature within a particular vineyard. Elevation, latitude, slope, and aspect all converge to form complex relationships with air temperatures; however, the relative degree to which these attributes affect temperatures varies between regions and is not well understood. This study examines the influence of geography and geomorphology on air temperatures within the American Viticultural Areas (AVAs) of the Columbia Basin in eastern Washington and Oregon. The premier vineyards within each AVA, which have been recognized for producing high-quality wine, were equipped with air temperature monitoring stations that collected hourly temperature measurements. A variety of temperature statistics were calculated, including daily average, maximum, and minimum temperatures. From these values, average diurnal variation and growing degree-days (10°C) were calculated. A variety of other statistics were computed, including date of first and last frost and time spent below a minimum temperature threshold. These parameters were compared to the vineyard's elevation, latitude, slope, aspect, and local topography using GPS, ArcCatalog, and GIS in an attempt to determine their relative influences on air temperatures. From these statistics, it was possible to delineate two trends of temperature variation controlled by elevation. In some AVAs, such as Walla Walla Valley and Red Mountain, average air temperatures increased with elevation because of the effect of cold air pooling on valley floors. In other AVAs, such as Horse Heaven Hills, Lake Chelan and Columbia Gorge, average temperatures decreased with elevation due to the moderating influences of the Columbia River and Lake Chelan. Other temperature statistics, including average diurnal range and maximum and minimum temperature, were influenced by relative topography, including local topography and slope. Vineyards with flat slopes that had low elevations relative to their surroundings had larger diurnal variations and lower maximum and minimum temperatures than vineyards with steeper slopes that were high relative to their surroundings.

Improving Forecast Skill by Assimilation of Quality-controlled AIRS Temperature Retrievals under Partially Cloudy Conditions

NASA Technical Reports Server (NTRS)

Reale, O.; Susskind, J.; Rosenberg, R.; Brin, E.; Riishojgaard, L.; Liu, E.; Terry, J.; Jusem, J. C.

2007-01-01

The National Aeronautics and Space Administration (NASA) Atmospheric Infrared Sounder (AIRS) on board the Aqua satellite has been long recognized as an important contributor towards the improvement of weather forecasts. At this time only a small fraction of the total data produced by AIRS is being used by operational weather systems. In fact, in addition to effects of thinning and quality control, the only AIRS data assimilated are radiance observations of channels unaffected by clouds. Observations in mid-lower tropospheric sounding AIRS channels are assimilated primarily under completely clear-sky conditions, thus imposing a very severe limitation on the horizontal distribution of the AIRS-derived information. In this work it is shown that the ability to derive accurate temperature profiles from AIRS observations in partially cloud-contaminated areas can be utilized to further improve the impact of AIRS observations in a global model and forecasting system. The analyses produced by assimilating AIRS temperature profiles obtained under partial cloud cover result in a substantially colder representation of the northern hemisphere lower midtroposphere at higher latitudes. This temperature difference has a strong impact, through hydrostatic adjustment, in the midtropospheric geopotential heights, which causes a different representation of the polar vortex especially over northeastern Siberia and Alaska. The AIRS-induced anomaly propagates through the model's dynamics producing improved 5-day forecasts.

Neutral temperature range in incubators: performance of equipment in current use and new developments.

PubMed

Libert, J P; Bach, V; Farges, G

1997-01-01

Low-birth-weight neonates should be nursed at thermoneutrality inside incubators. Thermoneutrality control is essential to enhance body growth and to reduce neonatal illnesses and mortality. Guidelines have been published to provide the thermoneutral range, but the recommendations did not always take into account all ambient and physiological parameters influencing thermoneutrality. In most marketed incubators, the heat supply is controlled through convective air flow (closed incubators) or through radiant power density (radiant warmer beds). The heating unit (on/off cycling or adjustable proportional control) is activated by an error signal calculated from the difference between a controlled temperature and a reference value preset by the clinician. The controlled variable can be either the incubator air or the skin temperature of the anterior abdominal region of the neonate. The neonate's size, thermal properties of the mattress and of incubator walls, air temperature and humidity, air velocity, incubator wall temperatures all influence the heat exchanges between the neonate and the surroundings, and, consequently, modify the obtention of thermoneutrality. Moreover, studies of the physiological mechanisms by which the neonate regulates body heat storage suggest that metabolic rate, behavior, vigilance level, nursing care, and heater control processes should also be taken into account. Little attention has been paid to these factors, and incubator performances are often disappointing. This article reviews the different factors that modify thermoneutral condition. An attempt is made to suggest new ways to design equipment incorporating these factors in algorithms controlling heater processes in order to reach the optimal thermal environment in which the neonate should be nursed.

Temperature uniformity in the CERN CLOUD chamber

NASA Astrophysics Data System (ADS)

Dias, António; Ehrhart, Sebastian; Vogel, Alexander; Williamson, Christina; Almeida, João; Kirkby, Jasper; Mathot, Serge; Mumford, Samuel; Onnela, Antti

2017-12-01

The CLOUD (Cosmics Leaving OUtdoor Droplets) experiment at CERN (European Council for Nuclear Research) investigates the nucleation and growth of aerosol particles under atmospheric conditions and their activation into cloud droplets. A key feature of the CLOUD experiment is precise control of the experimental parameters. Temperature uniformity and stability in the chamber are important since many of the processes under study are sensitive to temperature and also to contaminants that can be released from the stainless steel walls by upward temperature fluctuations. The air enclosed within the 26 m3 CLOUD chamber is equipped with several arrays (strings) of high precision, fast-response thermometers to measure its temperature. Here we present a study of the air temperature uniformity inside the CLOUD chamber under various experimental conditions. Measurements were performed under calibration conditions and run conditions, which are distinguished by the flow rate of fresh air and trace gases entering the chamber at 20 and up to 210 L min-1, respectively. During steady-state calibration runs between -70 and +20 °C, the air temperature uniformity is better than ±0.06 °C in the radial direction and ±0.1 °C in the vertical direction. Larger non-uniformities are present during experimental runs, depending on the temperature control of the make-up air and trace gases (since some trace gases require elevated temperatures until injection into the chamber). The temperature stability is ±0.04 °C over periods of several hours during either calibration or steady-state run conditions. During rapid adiabatic expansions to activate cloud droplets and ice particles, the chamber walls are up to 10 °C warmer than the enclosed air. This results in temperature differences of ±1.5 °C in the vertical direction and ±1 °C in the horizontal direction, while the air returns to its equilibrium temperature with a time constant of about 200 s.

Improving the performance of air-conditioning systems in an ASEAN (Association of South East Asian Nations) climate

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

Busch, J.F.; Warren, M.L.

1988-09-01

This paper describes an analysis of air conditioning performance under hot and humid tropical climate conditions appropriate to the Association of South East Asian Nations (ASEAN) countries. This region, with over 280 million people, has one of the fastest economic and energy consumption growth rates in the world. The work reported here is aimed at estimating the conservation potential derived from good design and control of air conditioning systems in commercial buildings. To test the performance of different air conditioning system types and control options, whole building energy performance was simulated using DOE-2. The 5100 m/sup 2/ (50,000 ft/sup 2/)more » prototype office building module was previously used in earlier commercial building energy standards analysis for Malaysia and Singapore. In general, the weather pattern for ASEAN countries is uniform, with hot and humid air masses known as ''monsoons'' dictating the weather patterns. Since a concentration of cities occurs near the tip of the Malay peninsula, hourly temperature, humidity, and wind speed data for Kuala Lumpur was used for the analysis. Because of the absence of heating loads in ASEAN regions, we have limited air conditioning configurations to two pipe fan coil, constant volume, variable air volume, powered induction, and ceiling bypass configurations. Control strategies were varied to determine the conservation potential in both energy use and peak electric power demands. Sensitivities including fan control, pre-cooling and night ventilation, supply air temperature control, zone temperature set point, ventilation and infiltration, daylighting and internal gains, and system sizing were examined and compared with a base case which was a variable air volume system with no reheat or economizer. Comfort issues, such as over-cooling and space humidity, were also examined.« less

AIR PASSIVATION OF METAL HYDRIDE BEDS FOR WASTE DISPOSAL

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

Klein, J; R. H. Hsu, R

2007-07-02

Metal hydride beds offer compact, safe storage of tritium. After metal hydride beds have reached the end of their useful life, the beds will replaced with new beds and the old beds prepared for disposal. One acceptance criteria for hydride bed waste disposal is that the material inside the bed not be pyrophoric. To determine the pyrophoric nature of spent metal hydride beds, controlled air ingress tests were performed. A simple gas handling manifold fitted with pressure transducers and a calibrated volume were used to introduce controlled quantities of air into a metal hydride bed and the bed temperature risemore » monitored for reactivity with the air. A desorbed, 4.4 kg titanium prototype hydride storage vessel (HSV) produced a 4.4 C internal temperature rise upon the first air exposure cycle and a 0.1 C temperature rise upon a second air exposure. A total of 346 scc air was consumed by the bed (0.08 scc per gram Ti). A desorbed, 9.66 kg LaNi{sub 4.25}Al{sub 0.75} prototype storage bed experienced larger temperature rises over successive cycles of air ingress and evacuation. The cycles were performed over a period of days with the bed effectively passivated after the 12th cycle. Nine to ten STP-L of air reacted with the bed producing both oxidized metal and water.« less

PID temperature controller in pig nursery: spatial characterization of thermal environment

NASA Astrophysics Data System (ADS)

de Souza Granja Barros, Juliana; Rossi, Luiz Antonio; Menezes de Souza, Zigomar

2018-05-01

The use of enhanced technologies of temperature control can improve the thermal conditions in environments of livestock facilities. The objective of this study was to evaluate the spatial distribution of the thermal environment variables in a pig nursery with a heating system with two temperature control technologies based on the geostatistical analysis. The following systems were evaluated: overhead electrical resistance with Proportional, Integral, and Derivative (PID) controller and overhead electrical resistance with a thermostat. We evaluated the climatic variables: dry bulb temperature (Tbs), air relative humidity (RH), temperature and humidity index (THI), and enthalpy in the winter, at 7:00, 12:00, and 18:00 h. The spatial distribution of these variables was mapped by kriging. The results showed that the resistance heating system with PID controllers improved the thermal comfort conditions in the pig nursery in the coldest hours, maintaining the spatial distribution of the air temperature more homogeneous in the pen. During the hottest weather, neither system provided comfort.

PID temperature controller in pig nursery: spatial characterization of thermal environment

NASA Astrophysics Data System (ADS)

de Souza Granja Barros, Juliana; Rossi, Luiz Antonio; Menezes de Souza, Zigomar

2017-11-01

The use of enhanced technologies of temperature control can improve the thermal conditions in environments of livestock facilities. The objective of this study was to evaluate the spatial distribution of the thermal environment variables in a pig nursery with a heating system with two temperature control technologies based on the geostatistical analysis. The following systems were evaluated: overhead electrical resistance with Proportional, Integral, and Derivative (PID) controller and overhead electrical resistance with a thermostat. We evaluated the climatic variables: dry bulb temperature (Tbs), air relative humidity (RH), temperature and humidity index (THI), and enthalpy in the winter, at 7:00, 12:00, and 18:00 h. The spatial distribution of these variables was mapped by kriging. The results showed that the resistance heating system with PID controllers improved the thermal comfort conditions in the pig nursery in the coldest hours, maintaining the spatial distribution of the air temperature more homogeneous in the pen. During the hottest weather, neither system provided comfort.

Control of membrane permeability in air-stable droplet interface bilayers

DOE PAGES

Mruetusatorn, Prachya; Polizos, Georgios; Datskos, Panos G.; ...

2015-03-19

Air-stable droplet interface bilayers (airDIBs) on oil-infused surfaces are versatile model membranes for synthetic biology applications, including biosensing of airborne species. However, air-DIBs are subject to evaporation, which can, over time, destabilize them and reduce their useful lifetime compared to traditional DIBs that are fully submerged in oil. Here, we show that lifetimes of air-DIBs can be extended by as much as an order of magnitude by maintaining them at a temperature just above the dew point. We find that raising the temperature from near the dew point (7 C at 38.5 % relative humidity) to room temperature results inmore » loss of water molecules of hydration from the polar head groups of the lipid bilayer membrane due to evaporation in an irreversible process that increases the overall entropy of the system. This dehydration transition affects primarily the bilayer resistance, by increasing ion permeability through the increasingly disordered polar head group region of the bilayer. Temperature and/or relative humidity are conveniently tunable parameters for controlling the stability and composition of air-DIBs membranes, while still allowing for operation in ambient environments.« less

Evaporative cooling of speleothem drip water

PubMed Central

Cuthbert, M. O.; Rau, G. C.; Andersen, M. S.; Roshan, H.; Rutlidge, H.; Marjo, C. E.; Markowska, M.; Jex, C. N.; Graham, P. W.; Mariethoz, G.; Acworth, R. I.; Baker, A.

2014-01-01

This study describes the first use of concurrent high-precision temperature and drip rate monitoring to explore what controls the temperature of speleothem forming drip water. Two contrasting sites, one with fast transient and one with slow constant dripping, in a temperate semi-arid location (Wellington, NSW, Australia), exhibit drip water temperatures which deviate significantly from the cave air temperature. We confirm the hypothesis that evaporative cooling is the dominant, but so far unattributed, control causing significant disequilibrium between drip water and host rock/air temperatures. The amount of cooling is dependent on the drip rate, relative humidity and ventilation. Our results have implications for the interpretation of temperature-sensitive, speleothem climate proxies such as δ18O, cave microecology and the use of heat as a tracer in karst. Understanding the processes controlling the temperature of speleothem-forming cave drip waters is vital for assessing the reliability of such deposits as archives of climate change. PMID:24895139

40 CFR 86.1868-12 - CO2 credits for improving the efficiency of air conditioning systems.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Creditvalue (g/mi) Reduced reheat, with externally-controlled, variable-displacement compressor (e.g. a compressor that controls displacement based on temperature setpoint and/or cooling demand of the air...-controlled, fixed-displacement or pneumatic variable displacement compressor (e.g. a compressor that controls...

Tuning Interfacial Properties and Processes by Controlling the Rheology and Structure of Poly( N-isopropylacrylamide) Particles at Air/Water Interfaces.

PubMed

Maestro, Armando; Jones, Daniel; Sánchez de Rojas Candela, Carmen; Guzman, Eduardo; Duits, Michel H G; Cicuta, Pietro

2018-06-05

By combining controlled experiments on single interfaces with measurements on solitary bubbles and liquid foams, we show that poly( N-isopropylacrylamide) (PNIPAM) microgels assembled at air/water interfaces exhibit a solid to liquid transition changing the temperature, and that this is associated with the change in the interfacial microstructure of the PNIPAM particles around their volume phase transition temperature. We show that the solid behaves as a soft 2D colloidal glass, and that the existence of this solid/liquid transition offers an ideal platform to tune the permeability of air bubbles covered by PNIPAM and to control macroscopic foam properties such as drainage, stability, and foamability. PNIPAM particles on fluid interfaces allow new tunable materials, for example foam structures with variable mechanical properties upon small temperature changes.

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.

No-reheat air-conditioning

NASA Technical Reports Server (NTRS)

Obler, H. D.

1980-01-01

Air conditioning system, for environmentally controlled areas containing sensitive equipment, regulates temperature and humidity without wasteful and costly reheating. System blends outside air with return air as dictated by various sensors to ensure required humidity in cooled spaces (such as computer room).

Cooling system with automated seasonal freeze protection

DOEpatents

Campbell, Levi A.; Chu, Richard C.; David, Milnes P.; Ellsworth, Jr., Michael J.; Iyengar, Madhusudan K.; Simons, Robert E.; Singh, Prabjit; Zhang, Jing

2016-05-24

An automated multi-fluid cooling system and method are provided for cooling an electronic component(s). The cooling system includes a coolant loop, a coolant tank, multiple valves, and a controller. The coolant loop is at least partially exposed to outdoor ambient air temperature(s) during normal operation, and the coolant tank includes first and second reservoirs containing first and second fluids, respectively. The first fluid freezes at a lower temperature than the second, the second fluid has superior cooling properties compared with the first, and the two fluids are soluble. The multiple valves are controllable to selectively couple the first or second fluid into the coolant in the coolant loop, wherein the coolant includes at least the second fluid. The controller automatically controls the valves to vary first fluid concentration level in the coolant loop based on historical, current, or anticipated outdoor air ambient temperature(s) for a time of year.

Cooling method with automated seasonal freeze protection

DOEpatents

Cambell, Levi; Chu, Richard; David, Milnes; Ellsworth, Jr, Michael; Iyengar, Madhusudan; Simons, Robert; Singh, Prabjit; Zhang, Jing

2016-05-31

An automated multi-fluid cooling method is provided for cooling an electronic component(s). The method includes obtaining a coolant loop, and providing a coolant tank, multiple valves, and a controller. The coolant loop is at least partially exposed to outdoor ambient air temperature(s) during normal operation, and the coolant tank includes first and second reservoirs containing first and second fluids, respectively. The first fluid freezes at a lower temperature than the second, the second fluid has superior cooling properties compared with the first, and the two fluids are soluble. The multiple valves are controllable to selectively couple the first or second fluid into the coolant in the coolant loop, wherein the coolant includes at least the second fluid. The controller automatically controls the valves to vary first fluid concentration level in the coolant loop based on historical, current, or anticipated outdoor air ambient temperature(s) for a time of year.

Resistive-heating or forced-air warming for the prevention of redistribution hypothermia.

PubMed

De Witte, Jan L; Demeyer, Caroline; Vandemaele, Els

2010-03-01

We evaluated the efficacy of resistive-heating or forced-air warming versus no prewarming, applied before induction of anesthesia for prevention of hypothermia. Twenty-seven patients scheduled for laparoscopic colorectal surgery were randomized into 1 of 3 groups: no prewarming; 30 minutes of prewarming with a carbon fiber total body cover at 42 degrees C; or 30 minutes of preoperative forced-air warming at 42 degrees C. The forced-air warming cover excluded the shoulders, ankles, and feet. The prewarming period was exactly 30 minutes. At the 31st minute, a total IV anesthesia technique was initiated, and all patients were actively warmed with a lithotomy blanket. Tympanic and distal esophageal temperatures were measured. Categorical data were analyzed using chi(2) test, and continuous data were analyzed with analysis of variance. P <0.05 was considered statistically significant. The mean esophageal temperatures differed significantly between the control and the carbon fiber group from 40 to 90 minutes of anesthesia. After 50 minutes of anesthesia, the mean esophageal temperatures in the control, carbon fiber, and forced-air groups were 35.9 degrees C +/- 0.3 degrees C, 36.5 degrees C +/- 0.4 degrees C, and 36.2 degrees C +/- 0.3 degrees C, respectively. No statistically significant difference was found between the forced-air and control groups. After 30 minutes of prewarming with resistive heating, patients had an esophageal temperature that was significantly higher than the control group. Prewarming should be considered part of the anesthetic management when patients are at risk for postoperative hypothermia.

Controlling a rabbet load and air/oil seal temperatures in a turbine

DOEpatents

Schmidt, Mark Christopher

2002-01-01

During a standard fired shutdown of a turbine, a loaded rabbet joint between the fourth stage wheel and the aft shaft of the machine can become unloaded causing a gap to occur due to a thermal mismatch at the rabbet joint with the bearing blower turned on. An open or unloaded rabbet could cause the parts to move relative to each other and therefore cause the rotor to lose balance. If the bearing blower is turned off during a shutdown, the forward air/oil seal temperature may exceed maximum design practice criterion due to "soak-back." An air/oil seal temperature above the established maximum design limits could cause a bearing fire to occur, with catastrophic consequences to the machine. By controlling the bearing blower according to an optimized blower profile, the rabbet load can be maintained, and the air/oil seal temperature can be maintained below the established limits. A blower profile is determined according to a thermodynamic model of the system.

21 CFR 113.40 - Equipment and procedures.

Code of Federal Regulations, 2014 CFR

2014-04-01

... have adequate filter systems to ensure a supply of clean, dry air. A steam controller activated by the... ensure a supply of clean, dry air. (5) Steam introduction. Steam shall be distributed in the bottom of... temperature controllers should have adequate filter systems to ensure a supply of clean, dry air. (5) Bleeders...

21 CFR 113.40 - Equipment and procedures.

Code of Federal Regulations, 2013 CFR

2013-04-01

... have adequate filter systems to ensure a supply of clean, dry air. A steam controller activated by the... ensure a supply of clean, dry air. (5) Steam introduction. Steam shall be distributed in the bottom of... temperature controllers should have adequate filter systems to ensure a supply of clean, dry air. (5) Bleeders...

21 CFR 113.40 - Equipment and procedures.

Code of Federal Regulations, 2012 CFR

2012-04-01

... have adequate filter systems to ensure a supply of clean, dry air. A steam controller activated by the... ensure a supply of clean, dry air. (5) Steam introduction. Steam shall be distributed in the bottom of... temperature controllers should have adequate filter systems to ensure a supply of clean, dry air. (5) Bleeders...

High-temperature controlled atmosphere for post-harvest control of Indian meal moth (Lepidoptera: Pyralidae) on preserved flowers.

PubMed

Sauer, Jodi A; Shelton, Mark D

2002-10-01

High carbon dioxide atmospheres combined with high temperature were effective for controlling Indian meal moth, Plodia interpunctella (Hübner) pupae. Pupae were exposed to atmospheres of 60, 80, or 98% carbon dioxide (CO2) in nitrogen (N2), or 60 or 80% CO2 in air at temperatures of 26.7 degrees C or 32.2 degrees C and 60% RH. Controlled atmosphere treatments at 32.2 degrees C controlled pupae faster than the same treatments at the lower temperature. At both temperatures high CO2 concentration treatments combined with nitrogen killed pupae faster than high CO2 concentration treatments combined with air. Exposure to 80% carbon dioxide mixed with nitrogen was the most effective treatment causing 100% mortality in 12 h at 32.2 degrees C and 93.3% mortality in 18 h at 26.6 degrees C. High-temperature controlled atmosphere treatments had no adverse effects on quality of two preserved floral products, Limonium sinuatum (L.) and Gypsophila elegans (Bieb.), tested for 12, 18, and 24 h according to industry standards.

Research on Vehicle Temperature Regulation System Based on Air Convection Principle

NASA Astrophysics Data System (ADS)

Zhuge, Muzi; Li, Xiang; Liang, Caifeng

2018-03-01

The long time parking outdoors in the summer will lead to too high temperature in the car, and the harmful gas produced by the vehicle engine will stay in the confined space for a long time during the parking process, which will do great harm to the human body. If the air conditioning system is turned on before driving, the cooling rate is slow and the battery loss is large. To solve the above problems, we designed a temperature adjusting system based on the principle of air convection. We can choose the automatic mode or manual mode to achieve control of a convection window. In the automatic mode, the system will automatically detect the environmental temperature, through the sensor to complete the detection, and the signal is transmitted to the microcontroller to control the window open or close, in manual mode, the remote control of the window can be realized by Bluetooth. Therefore, the system has important practical significance to effectively regulate temperature, prolong battery life, and improve the safety and comfort of traffic vehicles.

[Periodic fluctuation features of air temperature, precipitation, and aboveground net primary production of alpine meadow ecosystem on Qinghai-Tibetan Plateau].

PubMed

Zhang, Fa-wei; Li, Hong-qin; Li, Ying-nian; Li, Yi-kang; Lin, Li

2009-03-01

With Mexican Hat function as mother function, a wavelet analysis was conducted on the periodic fluctuation features of air temperature, precipitation, and aboveground net primary production (ANPP) in the Alpine Meadow Ecosystem Research Station, Chinese Academy of Sciences from 1980 to 2007. The results showed that there was a main period of 13 years for the annual fluctuations of air temperature, precipitation, and ANPP. A secondary period of 2 years for the annual fluctuations of air temperature and ANPP had lesser influence, whereas that of 4 years for the annual fluctuation of precipitation had greater effect. Lagged correlation analysis indicated that the annual fluctuation of ANNP was mainly controlled by the air temperature in a 20 years scale and had a weak 5-9 years lag effect, but there was a less correlation between ANPP and precipitation.

40 CFR 1033.505 - Ambient conditions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 1033.505 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS... presumed that combustion air will be drawn from the ambient air. Thus, the ambient temperature limits of this paragraph (a) apply for intake air upstream of the engine. If you do not draw combustion air from...

40 CFR 1033.505 - Ambient conditions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 1033.505 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS... presumed that combustion air will be drawn from the ambient air. Thus, the ambient temperature limits of this paragraph (a) apply for intake air upstream of the engine. If you do not draw combustion air from...

40 CFR 1033.505 - Ambient conditions.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 1033.505 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS... presumed that combustion air will be drawn from the ambient air. Thus, the ambient temperature limits of this paragraph (a) apply for intake air upstream of the engine. If you do not draw combustion air from...

40 CFR 1033.505 - Ambient conditions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 1033.505 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS... presumed that combustion air will be drawn from the ambient air. Thus, the ambient temperature limits of this paragraph (a) apply for intake air upstream of the engine. If you do not draw combustion air from...

40 CFR 1033.505 - Ambient conditions.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 1033.505 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS... presumed that combustion air will be drawn from the ambient air. Thus, the ambient temperature limits of this paragraph (a) apply for intake air upstream of the engine. If you do not draw combustion air from...

Biodiesel and Cold Temperature Effects on Speciated Mobile Source Air Toxics from Modern Diesel Trucks

EPA Science Inventory

Speciated volatile organic compounds (VOCs) with a particular focus on mobile source air toxics (MSATs) were measured in diesel exhaust from three heavy-duty trucks equipped with modern aftertreatment technologies. Emissions testing was conducted on a temperature controlled chass...

Biodiesel and Cold Temperature Effect on Speciated Mobile Source Air Toxics from Modern Diesel Trucks

EPA Science Inventory

Speciated volatile organic compounds (VOCs) with a particular focus on mobile source air toxics (MSATs) were measured in diesel exhaust from three heavy-duty trucks equipped with modern aftertreatment technologies. Emissions testing was conducted on a temperature controlled chass...

Component testing of a ground based gas turbine steam cooled rich-burn primary zone combustor for emissions control of nitrogeneous fuels

NASA Technical Reports Server (NTRS)

Schultz, D. F.

1986-01-01

This effort summarizes the work performed on a steam cooled, rich-burn primary zone, variable geometry combustor designed for combustion of nitrogeneous fuels such as heavy oils or synthetic crude oils. The steam cooling was employed to determine its feasibility and assess its usefulness as part of a ground based gas turbine bottoming cycle. Variable combustor geometry was employed to demonstrate its ability to control primary and secondary zone equivalence ratios and overall pressure drop. Both concepts proved to be highly successful in achieving their desired objectives. The steam cooling reduced peak liner temperatures to less than 800 K. This low temperature offers the potential of both long life and reduced use of strategic materials for liner fabrication. These degrees of variable geometry were successfully employed to control air flow distribution within the combustor. A variable blade angle axial flow air swirler was used to control primary zone air flow, while the secondary and tertiary zone air flows were controlled by rotating bands which regulated air flow to the secondary zone quench holes and the dilutions holes respectively.

Discussion on fresh air volume in Temperature and Humidity Independent Control of Air-conditioning System

NASA Astrophysics Data System (ADS)

Cheng, Xiaolong; Liu, Jinxiang; Wang, Yu; Yuan, Xiaolei; Jin, Hui

2018-05-01

The fresh air volume in Temperature and Humidity Independent Control of Air-conditioning System(THIC) of a typical office was comfirmed, under the premise of adopting the refrigeration dehumidifying fresh air unit(7°C/12°C). By detailed calculating the space moisture load and the fresh air volume required for dehumidification in 120 selected major cities in China, it can be inferred that the minimum fresh air volume required for dehumidification in THIC is mainly determined by the local outdoor air moisture and the outdoor wind speed; Then the mathematical fitting software Matlab was used to fit the three parameters, and a simplified formula for calculating the minimum per capita fresh air volume required for dehumidification was obtained; And the indoor relative humidity was simulated by the numerical software Airpak and the results by using the formula data and the data for hygiene were compared to verify the relibility of the simplified formula.

Air Pressure Controlled Mass Measurement System

NASA Astrophysics Data System (ADS)

Zhong, Ruilin; Wang, Jian; Cai, Changqing; Yao, Hong; Ding, Jin'an; Zhang, Yue; Wang, Xiaolei

Mass measurement is influenced by air pressure, temperature, humidity and other facts. In order to reduce the influence, mass laboratory of National Institute of Metrology, China has developed an air pressure controlled mass measurement system. In this system, an automatic mass comparator is installed in an airtight chamber. The Chamber is equipped with a pressure controller and associate valves, thus the air pressure can be changed and stabilized to the pre-set value, the preferred pressure range is from 200 hPa to 1100 hPa. In order to keep the environment inside the chamber stable, the display and control part of the mass comparator are moved outside the chamber, and connected to the mass comparator by feed-throughs. Also a lifting device is designed for this system which can easily lift up the upper part of the chamber, thus weights can be easily put inside the mass comparator. The whole system is put on a marble platform, and the temperature and humidity of the laboratory is very stable. The temperature, humidity, and carbon dioxide content inside the chamber are measured in real time and can be used to get air density. Mass measurement cycle from 1100 hPa to 200 hPa and back to 1100 hPa shows the effective of the system.

Adaptive fuzzy controller for thermal comfort inside the air-conditioned automobile chamber

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

Tong, L.; Yu, B.; Chen, Z.

1999-07-01

In order to meet the passengers' demand for thermal comfort, the adaptive fuzzy logic control design methodology is applied for the automobile airconditioner system. In accordance with the theory of air flow and heat transfer, the air temperature field inside the airconditioned automobile chamber is simulated by a set of simplified half-empirical formula. Then, instead of PMV (Predicted Mean Vote) criterion, RIV (Real Individual Vote) criterion is adopted as the base of the control for passengers' thermal comfort. The proposed controller is applied to the air temperature regulation at the individual passenger position. The control procedure is based on partitioningmore » the state space of the system into cell-groups and fuzzily quantificating the state space into these cells. When the system model has some parameter perturbation, the controller can also adjust its control parameters to compensate for the perturbation and maintain the good performance. The learning procedure shows its ideal effect in both computer simulation and experiments. The final results demonstrate the ideal performance of this adaptive fuzzy controller.« less

Effect of Several Factors on the Cooling of a Radial Engine in Flight

NASA Technical Reports Server (NTRS)

Schey, Oscar W; Pinkel, Benjamin

1936-01-01

Flight tests of a Grumman Scout (XSF-2) airplane fitted with a Pratt & Whitney 1535 supercharged engine were conducted to determine the effect of engine power, mass flow of the cooling air, and atmospheric temperature on cylinder temperature. The tests indicated that the difference in temperature between the cylinder wall and the cooling air varied as the 0.38 power of the brake horsepower for a constant mass flow of cooling air, cooling-air temperature, engine speed, and brake fuel consumption. The difference in temperature was also found to vary inversely as the 0.39 power of the mass flow for points on the head and the 0.35 power for points on the barrel, provided that engine power, engine speed, brake fuel consumption, and cooling-air temperature were kept constant. The results of the tests of the effect of atmospheric temperature on cylinder temperature were inconclusive owing to unfavorable weather conditions prevailing at the time of the tests. The method used for controlling the test conditions, however, was found to be feasible.

Influence of forced air volume on water evaporation during sewage sludge bio-drying.

PubMed

Cai, Lu; Chen, Tong-Bin; Gao, Ding; Zheng, Guo-Di; Liu, Hong-Tao; Pan, Tian-Hao

2013-09-01

Mechanical aeration is critical to sewage sludge bio-drying, and the actual water loss caused by aeration can be better understood from investigations of the relationship between aeration and water evaporation from the sewage sludge bio-drying pile based on in situ measurements. This study was conducted to investigate the effects of forced air volume on the evaporation of water from a sewage sludge bio-drying pile. Dewatered sewage sludge was bio-dried using control technology for bio-drying, during which time the temperature, superficial air velocity and water evaporation were measured and calculated. The results indicated that the peak air velocity and water evaporation occurred in the thermophilic phase and second temperature-increasing phase, with the highest values of 0.063 ± 0.027 m s(-1) and 28.9 kg ton(-1) matrix d(-1), respectively, being observed on day 4. Air velocity above the pile during aeration was 43-100% higher than when there was no aeration, and there was a significantly positive correlation between air volume and water evaporation from day 1 to 15. The order of daily means of water evaporation was thermophilic phase > second temperature-increasing phase > temperature-increasing phase > cooling phase. Forced aeration controlled the pile temperature and improved evaporation, making it the key factor influencing water loss during the process of sewage sludge bio-drying. Copyright © 2013 Elsevier Ltd. All rights reserved.

Automatic control study of the icing research tunnel refrigeration system

NASA Technical Reports Server (NTRS)

Kieffer, Arthur W.; Soeder, Ronald H.

1991-01-01

The Icing Research Tunnel (IRT) at the NASA Lewis Research Center is a subsonic, closed-return atmospheric tunnel. The tunnel includes a heat exchanger and a refrigeration plant to achieve the desired air temperature and a spray system to generate the type of icing conditions that would be encountered by aircraft. At the present time, the tunnel air temperature is controlled by manual adjustment of freon refrigerant flow control valves. An upgrade of this facility calls for these control valves to be adjusted by an automatic controller. The digital computer simulation of the IRT refrigeration plant and the automatic controller that was used in the simulation are discussed.

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

PubMed

Yang, B; Sekhar, S C; Melikov, A K

2010-08-01

The benefits of thermal comfort and indoor air quality with personalized ventilation (PV) systems have been demonstrated in recent studies. One of the barriers for wide spread acceptance by architects and HVAC designers has been attributed to challenges and constraints faced in the integration of PV systems with the work station. A newly developed ceiling-mounted PV system addresses these challenges and provides a practical solution while retaining much of the apparent benefits of PV systems. Assessments of thermal environment, air movement, and air quality for ceiling-mounted PV system were performed with tropically acclimatized subjects in a Field Environmental Chamber. Thirty-two subjects performed normal office work and could choose to be exposed to four different PV airflow rates (4, 8, 12, and 16 L/s), thus offering themselves a reasonable degree of individual control. Ambient temperatures of 26 and 23.5 degrees C and PV air temperatures of 26, 23.5, and 21 degrees C were employed. The local and whole body thermal sensations were reduced when PV airflow rates were increased. Inhaled air temperature was perceived cooler and perceived air quality and air freshness improved when PV airflow rate was increased or temperature was reduced. The newly developed ceiling-mounted PV system offers a practical solution to the integration of PV air terminal devices (ATDs) in the vicinity of the workstation. By remotely locating the PV ATDs on the ceiling directly above the occupants and under their control, the conditioned outdoor air is now provided to the occupants through the downward momentum of the air. A secondary air-conditioning and air distribution system offers additional cooling in the room and maintains a higher ambient temperature, thus offering significant benefits in conserving energy. The results of this study provide designers and consultants with needed knowledge for design of PV systems.

A whole-tree chamber system for examining tree-level physiological responses of field-grown trees to environmental variation and climate change.

PubMed

Medhurst, Jane; Parsby, Jan; Linder, Sune; Wallin, Göran; Ceschia, Eric; Slaney, Michelle

2006-09-01

A whole-tree chamber (WTC) system was installed at Flakaliden in northern Sweden to examine the long-term physiological responses of field-grown 40-year-old Norway spruce trees [Picea abies (L.) Karst.] to climate change. The WTCs were designed as large cuvettes to allow the net tree-level CO(2) and water fluxes to be measured on a continuous basis. A total of 12 WTCs were used to impose combinations of atmospheric carbon dioxide concentration, [CO(2)], and air temperature treatments. The air inside the ambient and elevated [CO(2)] WTCs was maintained at 365 and 700 micromol mol(-1), respectively. The air temperature inside the ambient temperature WTCs tracked air temperature outside the WTCs. Elevated temperatures were altered on a monthly time-step and ranged between +2.8 and +5.6 degrees C above ambient temperature. The system allowed continuous, long-term measurement of whole-tree photosynthesis, night-time respiration and transpiration. The performance of the WTCs was assessed using winter and spring data sets. The ability of the WTC system to measure tree-level physiological responses is demonstrated. All WTCs displayed a high level of control over tracking of air temperatures. The set target of 365 micromol mol(-1) in the ambient [CO(2)] chambers was too low to be maintained during winter because of tree dormancy and the high natural increase in [CO(2)] over winter at high latitudes such as the Flakaliden site. Accurate control over [CO(2)] in the ambient [CO(2)] chambers was restored during the spring and the system maintained the elevated [CO(2)] target of 700 micromol mol(-1) for both measurement periods. Air water vapour deficit (VPD) was accurately tracked in ambient temperature WTCs. However, as water vapour pressure in all 12 WTCs was maintained at the level of non-chambered (reference) air, VPD of elevated temperature WTCs was increased.

40 CFR 86.1868-12 - CO2 credits for improving the efficiency of air conditioning systems.

Code of Federal Regulations, 2014 CFR

2014-07-01

..., engine displacement, transmission class and configuration, interior volume, climate control system type... Creditvalue (g/mi) Reduced reheat, with externally-controlled, variable-displacement compressor (e.g. a compressor that controls displacement based on temperature setpoint and/or cooling demand of the air...

Effect of Elevated Atmospheric CO2 and Temperature on Leaf Optical Properties and Chlorophyll Content in Acer saccharum (Marsh.)

NASA Technical Reports Server (NTRS)

Carter, Gregory A.; Bahadur, Raj; Norby, Richard J.

1999-01-01

Elevated atmospheric CO2 pressure and numerous causes of plant stress often result in decreased leaf chlorophyll contents and thus would be expected to alter leaf optical properties. Hypotheses that elevated carbon dioxide pressure and air temperature would alter leaf optical properties were tested for sugar maple (Acer saccharum Marsh.) in the middle of its fourth growing season under treatment. The saplings had been growing since 1994 in open-top chambers at Oak Ridge, Tennessee under the following treatments: 1) Ambient CO2 pressure and air temperature (control); 2) CO2 pressure approximately 30 Pa above ambient; 3) Air temperatures 3 C above ambient; 4) Elevated CO2 and air temperature. Spectral reflectance, transmittance, and absorptance in the visible spectrum (400-720 nm) did not change significantly (rho = 0.05) in response to any treatment compared with control values. Although reflectance, transmittance, and absorptance at 700 nm correlated strongly with leaf chlorophyll content, chlorophyll content was not altered significantly by the treatments. The lack of treatment effects on pigmentation explained the non-significant change in optical properties in the visible spectrum. Optical properties in the near-infrared (721-850 nm) were similarly unresponsive to treatment with the exception of an increased absorptance in leaves that developed under elevated air temperature alone. This response could not be explained by the data, but might have resulted from effects of air temperature on leaf internal structure. Results indicated no significant potential for detecting leaf optical responses to elevated CO2 or temperature by the remote sensing of reflected radiation in the 400-850 nm spectrum.

Growth responses of male broilers subjected to increasing air velocities at high ambient temperatures and a high dew point.

PubMed

Dozier, W A; Lott, B D; Branton, S L

2005-06-01

This study examined live performance responses of male broilers to increasing air velocity of 120 and 180 m/min reared under high cyclic temperatures (25-35-25 degrees C) with a 23 degrees C dew point from 21 to 49 d. Birds were reared in an environmental facility containing 2 wind tunnels (4 pens/tunnel) and 6 floor pens (control). At 21 d, 53 birds were placed in each pen of the wind tunnels and control group, respectively, and growth performance was determined weekly. Increasing air velocity from 120 to 180 m/min improved BW and BW gain from 29 to 35, 36 to 42, and 43 to 49 d of age leading to a cumulative advantage of 287 g in BW gain and a 10-point difference in feed conversion from 21 to 49 d of age. Subjecting birds to air velocity improved growth rate, feed consumption, and feed conversion at each weekly interval from 28 to 49 d over the control birds. These results indicate that male broilers approximating 2.0 to 3.0 kg respond to an air velocity of 180 m/min when exposed to high cyclic temperatures.

System and method for conditioning intake air to an internal combustion engine

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

Sellnau, Mark C.

A system for conditioning the intake air to an internal combustion engine includes a means to boost the pressure of the intake air to the engine and a liquid cooled charge air cooler disposed between the output of the boost means and the charge air intake of the engine. Valves in the coolant system can be actuated so as to define a first configuration in which engine cooling is performed by coolant circulating in a first coolant loop at one temperature, and charge air cooling is performed by coolant flowing in a second coolant loop at a lower temperature. Themore » valves can be actuated so as to define a second configuration in which coolant that has flowed through the engine can be routed through the charge air cooler. The temperature of intake air to the engine can be controlled over a wide range of engine operation.« less

Engine Cylinder Temperature Control

DOEpatents

Kilkenny, Jonathan Patrick; Duffy, Kevin Patrick

2005-09-27

A method and apparatus for controlling a temperature in a combustion cylinder in an internal combustion engine. The cylinder is fluidly connected to an intake manifold and an exhaust manifold. The method and apparatus includes increasing a back pressure associated with the exhaust manifold to a level sufficient to maintain a desired quantity of residual exhaust gas in the cylinder, and varying operation of an intake valve located between the intake manifold and the cylinder to an open duration sufficient to maintain a desired quantity of fresh air from the intake manifold to the cylinder, wherein controlling the quantities of residual exhaust gas and fresh air are performed to maintain the temperature in the cylinder at a desired level.

Method for controlling exhaust gas heat recovery systems in vehicles

DOEpatents

Spohn, Brian L.; Claypole, George M.; Starr, Richard D

2013-06-11

A method of operating a vehicle including an engine, a transmission, an exhaust gas heat recovery (EGHR) heat exchanger, and an oil-to-water heat exchanger providing selective heat-exchange communication between the engine and transmission. The method includes controlling a two-way valve, which is configured to be set to one of an engine position and a transmission position. The engine position allows heat-exchange communication between the EGHR heat exchanger and the engine, but does not allow heat-exchange communication between the EGHR heat exchanger and the oil-to-water heat exchanger. The transmission position allows heat-exchange communication between the EGHR heat exchanger, the oil-to-water heat exchanger, and the engine. The method also includes monitoring an ambient air temperature and comparing the monitored ambient air temperature to a predetermined cold ambient temperature. If the monitored ambient air temperature is greater than the predetermined cold ambient temperature, the two-way valve is set to the transmission position.

[Effects of air temperature increase and precipitation change on grain yield and quality of spring wheat in semiarid area of Northwest China].

PubMed

Wang, He-ling; Zhang, Qiang; Wang, Run-yuan; Gan, Yan-tai; Niu, Jun-yi; Zhang, Kai; Zhao, Fu-nian; Zhao, Hong

2015-01-01

In order to predict effects of climate changing on growth, quality and grain yields of spring wheat, a field experiment was conducted to investigate the effects of air temperature increases (0 °C, 1.0 °C, 2.0° C and 3.0°) and precipitation variations (decrease 20%, unchanging and increase 20%) on grain yields, quality, diseases and insect pests of spring wheat at the Dingxi Arid Meteorology and Ecological Environment Experimental Station of the Institute of Arid Meteorology of China Meteorological Administration (35°35' N ,104°37' E). The results showed that effects of precipitation variations on kernel numbers of spring wheat were not significant when temperature increased by less than 2.0° C , but was significant when temperature increased by 3.0° C. Temperature increase enhanced kernel numbers, while temperature decrease reduced kernel numbers. The negative effect of temperature on thousand-kernel mass of spring wheat increased with increasing air temperature. The sterile spikelet of spring wheat response to air temperature was quadratic under all precipitation regimes. Compared with control ( no temperature increase), the decreases of grain yield of spring wheat when air temperature increased by 1.0°C, 2.0°C and 3.0°C under each of the three precipitation conditions (decrease 20%, no changing and increase 20%) were 12.1%, 24.7% and 42.7%, 8.4%, 15.1% and 21.8%, and 9.0%, 15.5% and 22.2%, respectively. The starch content of spring wheat decreased and the protein content increased with increasing air temperature. The number of aphids increased when air temperature increased by 2.0°C , but decreased when air temperature increased by 3.0°CT. The infection rates of rust disease increased with increasing air temperature.

Thermal modelling and control of 130kw direct contact (salt/air) heat exchanger

NASA Astrophysics Data System (ADS)

Qureshi, Omer A.; Calvet, Nicolas; Armstrong, Peter R.

2017-06-01

This work investigates the transient response of a certain type of direct contact heat exchanger (DCHX) that consists of packing (Raschig Rings) to increase the surface area for effective heat transfer between molten salt and air. Molten salt from the hot tank enters the heat exchanger (HX) and exit after heating the air still in the molten form. Thermal capacitance of the HX, mainly due to packing and resident salt inside the HX, results in strong transient response. Pure delay from salt residence time may also impact transient response. Both phenomena have been modelled in this paper. A Proportional-Integral controller (PI control) performance has been evaluated to maintain the minimum salt temperature above avoid crystallization temperature of the salt.

Sensitivity of cold acclimation to elevated autumn temperature in field-grown Pinus strobus seedlings

PubMed Central

Chang, Christine Y.; Unda, Faride; Zubilewich, Alexandra; Mansfield, Shawn D.; Ensminger, Ingo

2015-01-01

Climate change will increase autumn air temperature, while photoperiod decrease will remain unaffected. We assessed the effect of increased autumn air temperature on timing and development of cold acclimation and freezing resistance in Eastern white pine (EWP, Pinus strobus) under field conditions. For this purpose we simulated projected warmer temperatures for southern Ontario in a Temperature Free-Air-Controlled Enhancement (T-FACE) experiment and exposed EWP seedlings to ambient (Control) or elevated temperature (ET, +1.5°C/+3°C during day/night). Photosynthetic gas exchange, chlorophyll fluorescence, photoprotective pigments, leaf non-structural carbohydrates (NSC), and cold hardiness were assessed over two consecutive autumns. Nighttime temperature below 10°C and photoperiod below 12 h initiated downregulation of assimilation in both treatments. When temperature further decreased to 0°C and photoperiod became shorter than 10 h, downregulation of the light reactions and upregulation of photoprotective mechanisms occurred in both treatments. While ET seedlings did not delay the timing of the downregulation of assimilation, stomatal conductance in ET seedlings was decreased by 20–30% between August and early October. In both treatments leaf NSC composition changed considerably during autumn but differences between Control and ET seedlings were not significant. Similarly, development of freezing resistance was induced by exposure to low temperature during autumn, but the timing was not delayed in ET seedlings compared to Control seedlings. Our results indicate that EWP is most sensitive to temperature changes during October and November when downregulation of photosynthesis, enhancement of photoprotection, synthesis of cold-associated NSCs and development of freezing resistance occur. However, we also conclude that the timing of the development of freezing resistance in EWP seedlings is not affected by moderate temperature increases used in our field experiments. PMID:25852717

Minimum airflow reset of single-duct VAV terminal boxes

NASA Astrophysics Data System (ADS)

Cho, Young-Hum

Single duct Variable Air Volume (VAV) systems are currently the most widely used type of HVAC system in the United States. When installing such a system, it is critical to determine the minimum airflow set point of the terminal box, as an optimally selected set point will improve the level of thermal comfort and indoor air quality (IAQ) while at the same time lower overall energy costs. In principle, this minimum rate should be calculated according to the minimum ventilation requirement based on ASHRAE standard 62.1 and maximum heating load of the zone. Several factors must be carefully considered when calculating this minimum rate. Terminal boxes with conventional control sequences may result in occupant discomfort and energy waste. If the minimum rate of airflow is set too high, the AHUs will consume excess fan power, and the terminal boxes may cause significant simultaneous room heating and cooling. At the same time, a rate that is too low will result in poor air circulation and indoor air quality in the air-conditioned space. Currently, many scholars are investigating how to change the algorithm of the advanced VAV terminal box controller without retrofitting. Some of these controllers have been found to effectively improve thermal comfort, indoor air quality, and energy efficiency. However, minimum airflow set points have not yet been identified, nor has controller performance been verified in confirmed studies. In this study, control algorithms were developed that automatically identify and reset terminal box minimum airflow set points, thereby improving indoor air quality and thermal comfort levels, and reducing the overall rate of energy consumption. A theoretical analysis of the optimal minimum airflow and discharge air temperature was performed to identify the potential energy benefits of resetting the terminal box minimum airflow set points. Applicable control algorithms for calculating the ideal values for the minimum airflow reset were developed and applied to actual systems for performance validation. The results of the theoretical analysis, numeric simulations, and experiments show that the optimal control algorithms can automatically identify the minimum rate of heating airflow under actual working conditions. Improved control helps to stabilize room air temperatures. The vertical difference in the room air temperature was lower than the comfort value. Measurements of room CO2 levels indicate that when the minimum airflow set point was reduced it did not adversely affect the indoor air quality. According to the measured energy results, optimal control algorithms give a lower rate of reheating energy consumption than conventional controls.

An experimental study on effects of increased ventilation flow on students' perception of indoor environment in computer classrooms.

PubMed

Norbäck, D; Nordström, K

2008-08-01

The effects of ventilation in computer classrooms were studied with university students (n = 355) in a blinded study, 31% were women and 3.8% had asthma. Two classrooms had a higher air exchange (4.1-5.2 ac/h); two others had a lower air exchange (2.3-2.6 ac/h). After 1 week, ventilation conditions were shifted. The students reported environmental perceptions during the last hour. Room temperature, RH, CO2, PM10 and ultra-fine particles were measured simultaneously. Mean CO2 was 1185 ppm at lower and 922 ppm at higher air exchange. Mean temperature was 23.2 degrees C at lower and 22.1 degrees C at higher air exchange. After mutual adjustment (temperature, RH, CO2, air exchange), measured temperature was associated with a perception of higher temperature (P < 0.001), lower air movement (P < 0.001), and poorer air quality (P < 0.001). Higher air exchange was associated with a perception of lower temperature (P < 0.001), higher air movement (P = 0.001), and better air quality (P < 0.001). In the longitudinal analysis (n = 83), increased air exchange caused a perception of lower temperature (P = 0.002), higher air movement (P < 0.001), better air quality (P = 0.001), and less odor (P = 0.02). In conclusion, computer classrooms have CO2 levels above 1000 ppm and temperatures above 22 degrees C. Increased ventilation from 7 l/s per person to 10-13 l/s per person can improve thermal comfort and air quality. Computer classrooms are crowded indoor environments with a high thermal load from both students and computer equipment. It is important to control room temperature either by air conditioning, sun shields, or sufficiently high ventilation flow. A high ventilation flow is also crucial to achieving good perceived air quality. Personal ventilation flow should be at least 10 l/s. Possible loss of learning ability due to poor indoor air quality in university buildings deserves more attention.

Variations in incubator temperature and humidity management: a survey of current practice.

PubMed

Deguines, C; Décima, P; Pelletier, A; Dégrugilliers, L; Ghyselen, L; Tourneux, P

2012-03-01

To describe and assess routine procedures and practices for incubator temperature and humidity management in France in 2009. A questionnaire was sent to all the 186 neonatal care units in France. The questionnaire return rate was 86%. Seventy-five per cent of the units preferred skin servo-control to air temperature control in routine practice. Air temperature control was mainly used for infants with a gestational age of more than 28 weeks and aged over 7 days of life. In general, thermal management decisions did not depend on the infant's age but were based on a protocol applied specifically by each unit. All units humidified the incubator air, but there was a large difference between the lowest and highest reported humidity values (45% and 100% assumed to be a maximal value, respectively). More than 65% of the units used a fixed humidity value, rather than a variable, protocol-derived value. We observed large variations in incubator temperature and humidity management approaches from one neonatal care unit to another. There is a need for more evidence to better inform practice. A task force should be formed to guide clinical practice. © 2011 The Author(s)/Acta Paediatrica © 2011 Foundation Acta Paediatrica.

Stabilized three-stage oxidation of DME/air mixture in a micro flow reactor with a controlled temperature profile

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

Oshibe, Hiroshi; Nakamura, Hisashi; Tezuka, Takuya

Ignition and combustion characteristics of a stoichiometric dimethyl ether (DME)/air mixture in a micro flow reactor with a controlled temperature profile which was smoothly ramped from room temperature to ignition temperature were investigated. Special attention was paid to the multi-stage oxidation in low temperature condition. Normal stable flames in a mixture flow in the high velocity region, and non-stationary pulsating flames and/or repetitive extinction and ignition (FREI) in the medium velocity region were experimentally confirmed as expected from our previous study on a methane/air mixture. In addition, stable double weak flames were observed in the low velocity region for themore » present DME/air mixture case. It is the first observation of stable double flames by the present methodology. Gas sampling was conducted to obtain major species distributions in the flow reactor. The results indicated that existence of low-temperature oxidation was conjectured by the production of CH{sub 2}O occured in the upstream side of the experimental first luminous flame, while no chemiluminescence from it was seen. One-dimensional computation with detailed chemistry and transport was conducted. At low mixture velocities, three-stage oxidation was confirmed from profiles of the heat release rate and major chemical species, which was broadly in agreement with the experimental results. Since the present micro flow reactor with a controlled temperature profile successfully presented the multi-stage oxidations as spatially separated flames, it is shown that this flow reactor can be utilized as a methodology to separate sets of reactions, even for other practical fuels, at different temperature. (author)« less

International Space Station Common Cabin Air Assembly Condensing Heat Exchanger Hydrophilic Coating Operation, Recovery, and Lessons Learned

NASA Technical Reports Server (NTRS)

Balistreri, Steven F.; Steele, John W.; Caron, Mark E.; Laliberte, Yvon J.; Shaw, Laura A.

2013-01-01

The ability to control the temperature and humidity of an environment or habitat is critical for human survival. These factors are important to maintaining human health and comfort, as well as maintaining mechanical and electrical equipment in good working order to support the human and to accomplish mission objectives. The temperature and humidity of the International Space Station (ISS) United States On-orbit Segment (USOS) cabin air is controlled by the Common Cabin Air Assembly (CCAA). The CCAA consists of a fan, a condensing heat exchanger (CHX), an air/water separator, temperature and liquid sensors, and electrical controlling hardware and software. The CHX is the primary component responsible for control of temperature and humidity. The CCAA CHX contains a chemical coating that was developed to be hydrophilic and thus attract water from the humid influent air. This attraction forms the basis for water removal and therefore cabin humidity control. However, there have been several instances of CHX coatings becoming hydrophobic and repelling water. When this behavior is observed in an operational CHX in the ISS segments, the unit s ability to remove moisture from the air is compromised and the result is liquid water carryover into downstream ducting and systems. This water carryover can have detrimental effects on the ISS cabin atmosphere quality and on the health of downstream hardware. If the water carryover is severe and widespread, this behavior can result in an inability to maintain humidity levels in the USOS. This paper will describe the operation of the five CCAAs within the USOS, the potential causes of the hydrophobic condition, and the impacts of the resulting water carryover to downstream systems. It will describe the history of this behavior and the actual observed impacts to the ISS USOS. Information on mitigation steps to protect the health of future CHX hydrophilic coatings as well as remediation and recovery of the full heat exchanger will be discussed.

International Space Station Common Cabin Air Assembly Condensing Heat Exchanger Hydrophilic Coating Failures and Lessons Learned

NASA Technical Reports Server (NTRS)

Balistreri, Steven F.; Shaw, Laura A.; Laliberte, Yvon

2010-01-01

The ability to control the temperature and humidity of an environment or habitat is critical for human survival. These factors are important to maintaining human health and comfort, as well as maintaining mechanical and electrical equipment in good working order to support the human and to accomplish mission objectives. The temperature and humidity of the International Space Station (ISS) United States On-orbit Segment (USOS) cabin air is controlled by the Common Cabin Air Assembly (CCAA). The CCAA consists of a fan, a condensing heat exchanger (CHX), an air/water separator, temperature and liquid sensors, and electrical controlling hardware and software. The CHX is the primary component responsible for control of temperature and humidity. The CCAA CHX contains a chemical coating that was developed to be hydrophilic and thus attract water from the humid influent air. This attraction forms the basis for water removal and therefore cabin humidity control. However, there have been several instances of CHX coatings becoming hydrophobic and repelling water. When this behavior is observed in an operational CHX, the unit s ability to remove moisture from the air is compromised and the result is liquid water carryover into downstream ducting and systems. This water carryover can have detrimental effects on the cabin atmosphere quality and on the health of downstream hardware. If the water carryover is severe and widespread, this behavior can result in an inability to maintain humidity levels in the USOS. This paper will describe the operation of the five CCAAs within in the USOS, the potential causes of the hydrophobic condition, and the impacts of the resulting water carryover to downstream systems. It will describe the history of this behavior and the actual observed impacts to the ISS USOS. Information on mitigation steps to protect the health of future CHX hydrophilic coatings and potential remediation techniques will also be discussed.

40 CFR 86.1809-12 - Prohibition of defeat devices.

Code of Federal Regulations, 2010 CFR

2010-07-01

... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES (CONTINUED) General Compliance Provisions for Control of Air Pollution From New and In-Use Light-Duty Vehicles, Light... device. (c) For cold temperature CO and cold temperature NMHC emission control, the Administrator will...

40 CFR 86.1809-10 - Prohibition of defeat devices.

Code of Federal Regulations, 2010 CFR

2010-07-01

... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES (CONTINUED) General Compliance Provisions for Control of Air Pollution From New and In-Use Light-Duty Vehicles, Light... device. (c) For cold temperature CO and cold temperature NMHC emission control, the Administrator will...

40 CFR 86.1809-12 - Prohibition of defeat devices.

Code of Federal Regulations, 2013 CFR

2013-07-01

... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES (CONTINUED) General Compliance Provisions for Control of Air Pollution From New and In-Use Light-Duty Vehicles, Light... device. (c) For cold temperature CO and cold temperature NMHC emission control, the Administrator will...

40 CFR 86.1809-10 - Prohibition of defeat devices.

Code of Federal Regulations, 2011 CFR

2011-07-01

... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES (CONTINUED) General Compliance Provisions for Control of Air Pollution From New and In-Use Light-Duty Vehicles, Light... device. (c) For cold temperature CO and cold temperature NMHC emission control, the Administrator will...

40 CFR 86.1809-10 - Prohibition of defeat devices.

Code of Federal Regulations, 2013 CFR

2013-07-01

... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES (CONTINUED) General Compliance Provisions for Control of Air Pollution From New and In-Use Light-Duty Vehicles, Light... device. (c) For cold temperature CO and cold temperature NMHC emission control, the Administrator will...

40 CFR 86.1809-12 - Prohibition of defeat devices.

Code of Federal Regulations, 2011 CFR

2011-07-01

... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES (CONTINUED) General Compliance Provisions for Control of Air Pollution From New and In-Use Light-Duty Vehicles, Light... device. (c) For cold temperature CO and cold temperature NMHC emission control, the Administrator will...

Performance of Control System Using Microcontroller for Sea Water Circulation

NASA Astrophysics Data System (ADS)

Indriani, A.; Witanto, Y.; Pratama, A. S.; Supriyadi; Hendra; Tanjung, A.

2018-02-01

Now a day control system is very important rule for any process. Control system have been used in the automatic system. Automatic system can be seen in the industrial filed, mechanical field, electrical field and etc. In industrial and mechanical field, control system are used for control of motion component such as motor, conveyor, machine, control of process made of product, control of system and soon. In electrical field, control system can met for control of electrical system as equipment or part electrical like fan, rice cooker, refrigerator, air conditioner and etc. Control system are used for control of temperature and circulation gas, air and water. Control system of temperature and circulation of water also can be used for fisher community. Control system can be create by using microcontroller, PLC and other automatic program [1][2]. In this paper we will focus on the close loop system by using microcontroller Arduino Mega to control of temperature and circulation of sea water for fisher community. Performance control system is influenced by control equipment, sensor sensitivity, test condition, environment and others. The temperature sensor is measured using the DS18S20 and the sea water clarity sensor for circulation indicator with turbidity sensor. From the test results indicated that this control system can circulate sea water and maintain the temperature and clarity of seawater in a short time.

Conceptual Study of the LB/TS (Large Blast/Thermal Simulator) Instrumentation, Data Acquisition and Facility Controls System.

DTIC Science & Technology

1984-09-12

423, R. Jones ATTN: DAEN-ECE-T ATTN: DAEN-RDL DEPARTMENT OF THE AIR FORCE ATTN: DAEN-RDM. J. Healy ATTN: DAEN-ZCM Air Force Engineering & Services Ctr...31 7 Comparison Chart of Various Femperature Sensors (Prepared by HY-CAL Engineering ) ... ...... 36 8 Temperature Sensor Requirements and...Positions * TRS Valve Positions; LOX, AL, N2 Solenoid and Control . - Valve Positions 1.4 Air Compressor System Control * Valve Positions 0 Pressure

Increased ambient air temperature alters the severity of soil water repellency

NASA Astrophysics Data System (ADS)

van Keulen, Geertje; Sinclair, Kat; Hallin, Ingrid; Doerr, Stefan; Urbanek, Emilia; Quinn, Gerry; Matthews, Peter; Dudley, Ed; Francis, Lewis; Gazze, S. Andrea; Whalley, Richard

2017-04-01

Soil repellency, the inability of soils to wet readily, has detrimental environmental impacts such as increased runoff, erosion and flooding, reduced biomass production, inefficient use of irrigation water and preferential leaching of pollutants. Its impacts may exacerbate (summer) flood risks associated with more extreme drought and precipitation events. In this study we have tested the hypothesis that transitions between hydrophobic and hydrophilic soil particle surface characteristics, in conjunction with soil structural properties, strongly influence the hydrological behaviour of UK soils under current and predicted UK climatic conditions. We have addressed the hypothesis by applying different ambient air temperatures under controlled conditions to simulate the effect of predicted UK climatic conditions on the wettability of soils prone to develop repellency at different severities. Three UK silt-loam soils under permanent vegetation were selected for controlled soil perturbation studies. The soils were chosen based on the severity of hydrophobicity that can be achieved in the field: severe to extreme (Cefn Bryn, Gower, Wales), intermediate to severe (National Botanical Garden, Wales), and subcritical (Park Grass, Rothamsted Research near London). The latter is already highly characterised so was also used as a control. Soils were fully saturated with water and then allowed to dry out gradually upon exposure to controlled laboratory conditions. Soils were allowed to adapt for a few hours to a new temperature prior to initiation of the controlled experiments. Soil wettability was determined at highly regular intervals by measuring water droplet penetration times. Samples were collected at four time points: fully wettable, just prior to and after the critical soil moisture concentrations (CSC), and upon reaching air dryness (to constant weight), for further (ultra)metaproteomic and nanomechanical studies to allow integration of bulk soil characterisations with functional expression and nanoscale studies to generate deep mechanistic understanding of the roles of microbes in soil ecosystems. Our controlled soil pertubation studies have shown that an increase in ambient temperature has consistently affected the severity of soil water repellency. Surprisingly, a higher ambient air temperature impacts soils that in the field develop subcritical and extreme repellency, differently under controlled laboratory conditions. We will discuss the impact of these results in relation to predicted UK climatic conditions. Soil metaproteomics will provide mechanistic insight at the molecular level whether differential microbial adaptation is correlated with the apparent different response to a higher ambient air temperature.

40 CFR Appendix I to Part 94 - Emission-Related Engine Parameters and Specifications

Code of Federal Regulations, 2012 CFR

2012-07-01

.... Temperature control system calibration. 4. Maximum allowable inlet air restriction. III. Fuel System. 1. General. a. Engine idle speed. 2. Fuel injection—compression ignition engines. a. Control parameters and calibrations. b. Transient enrichment system calibration. c. Air-fuel flow calibration. d. Altitude...

40 CFR Appendix I to Part 94 - Emission-Related Engine Parameters and Specifications

Code of Federal Regulations, 2011 CFR

2011-07-01

.... Temperature control system calibration. 4. Maximum allowable inlet air restriction. III. Fuel System. 1. General. a. Engine idle speed. 2. Fuel injection—compression ignition engines. a. Control parameters and calibrations. b. Transient enrichment system calibration. c. Air-fuel flow calibration. d. Altitude...

40 CFR Appendix I to Part 94 - Emission-Related Engine Parameters and Specifications

Code of Federal Regulations, 2014 CFR

2014-07-01

.... Temperature control system calibration. 4. Maximum allowable inlet air restriction. III. Fuel System. 1. General. a. Engine idle speed. 2. Fuel injection—compression ignition engines. a. Control parameters and calibrations. b. Transient enrichment system calibration. c. Air-fuel flow calibration. d. Altitude...

40 CFR Appendix I to Part 94 - Emission-Related Engine Parameters and Specifications

Code of Federal Regulations, 2013 CFR

2013-07-01

.... Temperature control system calibration. 4. Maximum allowable inlet air restriction. III. Fuel System. 1. General. a. Engine idle speed. 2. Fuel injection—compression ignition engines. a. Control parameters and calibrations. b. Transient enrichment system calibration. c. Air-fuel flow calibration. d. Altitude...

Effects of Temperature on the Performance of a Small Internal Combustion Engine at Altitude

DTIC Science & Technology

2013-03-21

flexible diaphragm was attached to damp out pulses in the air flow pulsations . Their method of temperature control was electric heating of the intake air...42  Figure 14. Heat exchanger ................................................................................................ 45  Figure...15. Both liquid nitrogen lines from Dewar ............................................................ 45  Figure 16. Engine inlet flow path heat

System and method of providing quick thermal comfort with reduced energy by using directed spot conditioning

DOEpatents

Wang, Mingyu; Kadle, Prasad S.; Ghosh, Debashis; Zima, Mark J.; Wolfe, IV, Edward; Craig, Timothy D

2016-10-04

A heating, ventilation, and air conditioning (HVAC) system and a method of controlling a HVAC system that is configured to provide a perceived comfortable ambient environment to an occupant seated in a vehicle cabin. The system includes a nozzle configured to direct an air stream from the HVAC system to the location of a thermally sensitive portion of the body of the occupant. The system also includes a controller configured to determine an air stream temperature and an air stream flow rate necessary to establish the desired heat supply rate for the sensitive portion and provide a comfortable thermal environment by thermally isolating the occupant from the ambient vehicle cabin temperature. The system may include a sensor to determine the location of the sensitive portion. The nozzle may include a thermoelectric device to heat or cool the air stream.

Zero Power Warming (ZPW) Chamber Prototype Measurements, Barrow, Alaska, 2016

DOE Data Explorer

Shawn Serbin; Alistair Rogers; Kim Ely

2017-02-10

Data were collected during one season of prototyping associated with the development of a passive warming technology. An experimental chamber, the Zero Power Warming (ZPW) chamber, was fitted with apparatus to modulate venting of a field enclosure and enhance elevation of air temperature by solar radiation. The ZPW chamber was compared with a control chamber (Control) and an ambient open air plot (Ambient). The control chamber was identical to the ZPW chamber but lacked the apparatus necessary to modulate venting, the chamber vents in the control chamber were fixed open for the majority of the trial period. The three plots were located over Carex aquatilis growing in an area of moderately degraded permafrost. Chambers were placed on the same footprints that were used for a similar exercise in 2015 (no data) and therefore those plots had experienced some thaw and degradation prior to 2016. The following data were collected for 80 days at 1 minute intervals from within two chambers and an ambient plot: solar input, chamber venting, air temperature, relative humidity, soil temperature (at 5, 10 and 15 cm), soil moisture, downward and upward NIR.

New control design principles based on measured performance and energy analysis of HVAC (Heating, Ventilating, and Air-Conditioning) systems

NASA Astrophysics Data System (ADS)

Hittle, D. C.; Johnson, D. L.

1985-01-01

This report is one of a series on the development of heating, ventilating, and air-conditioning (HVAC) control systems that are simple, efficient, reliable, maintainable, and well-documented. This report identifies major problems associated with three currently used HVAC control systems. It also describes the development of a retrofit control system applicable to military buildings that will allow easy identification of component failures, facilitate repair, and minimize system failures. Evaluation of currently used controls showed that pneumatic temperature control equipment requires a very clean source of supply air and is also not very accurate. Pneumatic, rather than electronic, actuators should be used because they are cheaper and require less maintenance. Thermistor temperature detectors should not be used for HVAC applications because they require frequent calibration. It was found that enthalpy economy cycles cannot be used for control because the humidity sensors required for their use are prone to rapid drift, inaccurate, and hard to calibrate in the field. Performance of control systems greatly affects HVAC operating costs. Significant savings can be achieved if proportional-plus-integral control schemes are used. Use of the retrofit prototype control panel developed in this study on variable-air-volume systems should provide significant energy cost savings, improve comfort and reliability, and reduce maintenance costs.

40 CFR Appendix I to Part 94 - Emission-Related Engine Parameters and Specifications

Code of Federal Regulations, 2010 CFR

2010-07-01

... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM MARINE COMPRESSION-IGNITION ENGINES Pt. 94, App. I Appendix...—Reciprocating Engines. 1. Compression ratio. 2. Type of air aspiration (natural, Roots blown, supercharged.... Temperature control system calibration. 4. Maximum allowable inlet air restriction. III. Fuel System. 1...

Recent advances of rearing cabinet instrumentation and control system for insect stock culture

NASA Astrophysics Data System (ADS)

Hermawan, Wawan; Kasmara, Hikmat; Melanie, Panatarani, Camellia; Joni, I. Made

2017-01-01

Helicoverpa armigera (Hubner) is one of a serious pest of horticulture in Indonesia. Helicoverpa armigera Nuclear Polyhedrovirus (HaNPV) has attracted interest for many researchers as a pest control for larvae of this species. Currently, we investigating the agrochemical formulations of HaNPV by introducing nanotechnology. Thus it is required an acceptable efficiency of insect stock cultures equipped with advance instruments to resolve the difficulties on insect stock seasons dependency. In addition, it is important to improve the insect survival with the aid of artificial natural environment and gain high insect production. This paper reports the rearing cabinet used as preparation of stock culture includes air-conditioning system, lighting, i.e. day and night control, and the main principles on recent technical and procedural advances apparatus of the system. The rearing system was moveable, designed and build by allowing air-conditioned cabinet for rearing insects, air motion and distribution as well as temperature and humidity being precisely controlled. The air was heated, humidified, and dehumidified respectively using a heater and ultrasonic nebulizer as actuators. Temperature and humidity can be controlled at any desired levels from room temperature (20°C) to 40 ± 1°C and from 0 to 80% RH with an accuracy of ±3% R.H. It is concluded that the recent design has acceptable performance based on the defined requirement for insect rearing and storage.

Temperature-related mortality estimates after accounting for the cumulative effects of air pollution in an urban area.

PubMed

Stanišić Stojić, Svetlana; Stanišić, Nemanja; Stojić, Andreja

2016-07-11

To propose a new method for including the cumulative mid-term effects of air pollution in the traditional Poisson regression model and compare the temperature-related mortality risk estimates, before and after including air pollution data. The analysis comprised a total of 56,920 residents aged 65 years or older who died from circulatory and respiratory diseases in Belgrade, Serbia, and daily mean PM10, NO2, SO2 and soot concentrations obtained for the period 2009-2014. After accounting for the cumulative effects of air pollutants, the risk associated with cold temperatures was significantly lower and the overall temperature-attributable risk decreased from 8.80 to 3.00 %. Furthermore, the optimum range of temperature, within which no excess temperature-related mortality is expected to occur, was very broad, between -5 and 21 °C, which differs from the previous findings that most of the attributable deaths were associated with mild temperatures. These results suggest that, in polluted areas of developing countries, most of the mortality risk, previously attributed to cold temperatures, can be explained by the mid-term effects of air pollution. The results also showed that the estimated relative importance of PM10 was the smallest of four examined pollutant species, and thus, including PM10 data only is clearly not the most effective way to control for the effects of air pollution.

HIGH REACTIVITY SORBENTS FOR SO2 CONTROL

EPA Science Inventory

The paper discusses studies, relating to air pollution control from coal-fired utility boilers, that show that the primary variable affecting sorbent reactivity at high temperature or at low temperature with water droplets is surface area. For the development of high surface area...

Multichannel temperature controller for hot air solar house

NASA Technical Reports Server (NTRS)

Currie, J. R.

1979-01-01

This paper describes an electronic controller that is optimized to operate a hot air solar system. Thermal information is obtained from copper constantan thermocouples and a wall-type thermostat. The signals from the thermocouples are processed through a single amplifier using a multiplexing scheme. The multiplexing reduces the component count and automatically calibrates the thermocouple amplifier. The processed signals connect to some simple logic that selects one of the four operating modes. This simple, inexpensive, and reliable scheme is well suited to control hot air solar systems.

Internal combustion engine controls for reduced exhausts contaminants

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

Matthews, D.R. Jr.

1974-06-04

An electrochemical control system for achieving optimum efficiency in the catalytic conversion of hydrocarbon and carbon monoxide emissions from internal combustion engines is described. The system automatically maintains catalyst temperature at a point for maximum pollutant conversion by adjusting ignition timing and fuel/air ratio during warm-up and subsequent operation. Ignition timing is retarded during engine warm-up to bring the catalytic converter to an efficient operating temperature within a minimum period of time. After the converter reaches a predetermined minimum temperature, the spark is advanced to within its normal operating range. A needle-valve adjustment during warm-up is employed to enrich themore » fuel/air mixture by approximately 10 percent. Following warm-up and attainment of a predetermined catalyst temperature, the needle valve is moved automatically to its normal position (e.g., a fuel/air ratio of 16:1). Although the normal lean mixture causes increased amounts of nitrogen oxide emissions, present NO/sub x/ converters appear capable of handling the increased emissions under normal operating conditions.« less

Modeling of Hydrate Formation Mode in Raw Natural Gas Air Coolers

NASA Astrophysics Data System (ADS)

Scherbinin, S. V.; Prakhova, M. Yu; Krasnov, A. N.; Khoroshavina, E. A.

2018-05-01

Air cooling units (ACU) are used at all the gas fields for cooling natural gas after compressing. When using ACUs on raw (wet) gas in a low temperature condition, there is a danger of hydrate plug formation in the heat exchanging tubes of the ACU. To predict possible hydrate formation, a mathematical model of the air cooler thermal behavior used in the control system shall adequately calculate not only gas temperature at the cooler's outlet, but also a dew point value, a temperature at which condensation, as well as the gas hydrate formation point, onsets. This paper proposes a mathematical model allowing one to determine the pressure in the air cooler which makes hydrate formation for a given gas composition possible.

Air quality and ventilation fan control based on aerosol measurement in the bi-directional undersea Bømlafjord tunnel.

PubMed

Indrehus, Oddny; Aralt, Tor Tybring

2005-04-01

Aerosol, NO and CO concentration, temperature, air humidity, air flow and number of running ventilation fans were measured by continuous analysers every minute for a whole week for six different one-week periods spread over ten months in 2001 and 2002 at measuring stations in the 7860 m long tunnel. The ventilation control system was mainly based on aerosol measurements taken by optical scatter sensors. The ventilation turned out to be satisfactory according to Norwegian air quality standards for road tunnels; however, there was some uncertainty concerning the NO2 levels. The air humidity and temperature inside the tunnel were highly influenced by the outside metrological conditions. Statistical models for NO concentration were developed and tested; correlations between predicted and measured NO were 0.81 for a partial least squares regression (PLS1) model based on CO and aerosol, and 0.77 for a linear regression model based only on aerosol. Hence, the ventilation control system should not solely be based on aerosol measurements. Since NO2 is the hazardous polluter, modelling NO2 concentration rather than NO should be preferred in any further optimising of the ventilation control.

Quantifying energy and mass transfer in crop canopies: sensors for measurement of temperature and air velocity

NASA Technical Reports Server (NTRS)

Bugbee, B.; Monje, O.; Tanner, B.

1996-01-01

Here we report on the in situ performance of inexpensive, miniature sensors that have increased our ability to measure mass and energy fluxes from plant canopies in controlled environments: 1. Surface temperature. Canopy temperature measurements indicate changes in stomatal aperture and thus latent and sensible heat fluxes. Infrared transducers from two manufacturers (Exergen Corporation, Newton, MA; and Everest Interscience, Tucson, AZ, USA) have recently become available. Transducer accuracy matched that of a more expensive hand-held infrared thermometer. 2. Air velocity varies above and within plant canopies and is an important component in mass and energy transfer models. We tested commercially-available needle, heat-transfer anemometers (1 x 50 mm cylinder) that consist of a fine-wire thermocouple and a heater inside a hypodermic needle. The needle is heated and wind speed determined from the temperature rise above ambient. These sensors are particularly useful in measuring the low wind speeds found within plant canopies. 3. Accurate measurements of air temperature adjacent to plant leaves facilitates transport phenomena modeling. We quantified the effect of radiation and air velocity on temperature rise in thermocouples from 10 to 500 micrometers. At high radiation loads and low wind speeds, temperature errors were as large as 7 degrees C above air temperature.

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.

93. TEMPERATURE AND FLOW RATE CONTROLS FOR SYSTEM 1 AND ...

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

93. TEMPERATURE AND FLOW RATE CONTROLS FOR SYSTEM 1 AND SYSTEM 2, FACING WEST IN MECHANICAL EQUIPMENT ROOM (101), LSB (BLDG. 770) - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 West, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

Air temperature optimisation for humidity-controlled cold storage of the predatory mites Neoseiulus californicus and Phytoseiulus persimilis (Acari: Phytoseiidae).

PubMed

Ghazy, Noureldin Abuelfadl; Suzuki, Takeshi; Amano, Hiroshi; Ohyama, Katsumi

2014-03-01

Humidity-controlled cold storage, in which the water vapour pressure is saturated, can prolong the survival of the predatory mites Neoseiulus californicus (McGregor) and Phytoseiulus persimilis Athias-Henriot (Acari: Phytoseiidae). However, information on the optimum air temperature for long-term storage by this method is limited. The authors evaluated the survival of mated adult females of N. californicus and P. persimilis at 5.0, 7.5, 10.0 and 12.5 °C under saturated water vapour condition (vapour pressure deficit 0.0 kPa). N. californicus showed a longer survival time than P. persimilis at all the air temperatures. The longest mean survival time of N. californicus was 11 weeks at 7.5 °C, whereas that of P. persimilis was 8 weeks at 5.0 °C. After storage at 7.5 °C for 8 weeks, no negative effect on post-storage oviposition was observed in N. californicus, whereas the oviposition of P. persimilis stored at 5.0 °C for 8 weeks was significantly reduced. The interspecific variation in the response of these predators to low air temperature might be attributed to their natural habitat and energy requirements. These results may be useful for the long-term storage of these predators, which is required for cost-effective biological control. © 2013 Society of Chemical Industry.

The impact of elevated CO2 and temperature on grain quality of rice grown under open-air field conditions.

PubMed

Jing, Liquan; Wang, Juan; Shen, Shibo; Wang, Yunxia; Zhu, Jianguo; Wang, Yulong; Yang, Lianxin

2016-08-01

Rising atmospheric CO2 is accompanied by global warming. However, interactive effects of elevated CO2 and temperature have not been well studied on grain quality of rice. A japonica cultivar was grown in the field using a free-air CO2 enrichment facility in combination with a canopy air temperature increase system in 2014. The gas fumigation (200 µmol mol(-1) above ambient CO2 ) and temperature increase (1 °C above ambient air temperature) were performed from tillering until maturity. Compared with the control (ambient CO2 and air temperature), elevated CO2 increased grain length and width as well as grain chalkiness but decreased protein concentrations. In contrast, the increase in canopy air temperature had less effect on these parameters except for grain chalkiness. The starch pasting properties of rice flour and taste analysis of cooked rice indicated that the palatability of rice was improved by CO2 and/or temperature elevation, with the combination of the two treatments showing the most significant changes compared with ambient rice. It is concluded that projected CO2 in 2050 may have larger effects on rice grain quality than the projected temperature increase. Although deterioration in milling suitability, grain appearance and nutritional quality can be expected, the taste of cooked rice might be better in the future environment. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

Ice Surface Temperature Variability in the Polar Regions and the Relationships to 2 Meter Air Temperatures

NASA Astrophysics Data System (ADS)

Hoyer, J.; Madsen, K. S.; Englyst, P. N.

2017-12-01

Determining the surface and near surface air temperature from models or observations in the Polar Regions is challenging due to the extreme conditions and the lack of in situ observations. The errors in near surface temperature products are typically larger than for other regions of the world, and the potential for using Earth Observations is large. As part of the EU project, EUSTACE, we have developed empirical models for the relationship between the satellite observed skin ice temperatures and 2m air temperatures. We use the Arctic and Antarctic Sea and sea ice Surface Temperatures from thermal Infrared satellite sensors (AASTI) reanalysis to estimate daily surface air temperature over land ice and sea ice for the Arctic and the Antarctic. Large efforts have been put into collecting and quality controlling in situ observations from various data portals and research projects. The reconstruction is independent of numerical weather prediction models and thus provides an important alternative to modelled air temperature estimates. The new surface air temperature data record has been validated against more than 58.000 independent in situ measurements for the four surface types: Arctic sea ice, Greenland ice sheet, Antarctic sea ice and Antarctic ice sheet. The average correlations are 92-97% and average root mean square errors are 3.1-3.6°C for the four surface types. The root mean square error includes the uncertainty of the in-situ measurement, which ranges from 0.5 to 2°C. A comparison with ERA-Interim shows a consistently better performance of the satellite based air temperatures than the ERA-Interim for the Greenland ice sheet, when compared against observations not used in any of the two estimates. This is encouraging and demonstrates the values of these products. In addition, the procedure presented here works on satellite observations that are available in near real time and this opens up for a near real time estimation of the surface air temperature over ice from satellites.

Parametric study of a concentric coaxial glass tube solar air collector: a theoretical approach

NASA Astrophysics Data System (ADS)

Dabra, Vishal; Yadav, Avadhesh

2018-06-01

Concentric coaxial glass tube solar air collector (CCGTSAC) is a quite innovative development in the field of solar collectors. This type of collector is specially designed to produce hot air. A mathematical model based on the energy conservation equations for small control volumes along the axial direction of concentric coaxial glass tube (CCGT) is developed in this paper. It is applied to predict the effect of thirteen different parameters on the exit air temperature rise and appeared that absorber tube size, length of CCGT, absorptivity of transparent glazing, transmissivity of transparent glazing, absorptivity of absorber coating, inlet or ambient air temperature, mass flow rate, variation of thermo-physical properties of air, wind speed, solar intensity and vacuum present between transparent glazing and absorber tube are significant parameters. Results of the model were analysed to predict the effect of key parameters on the thermal performance of a CCGTSAC for exit air temperature rise about 43.9-58.4 °C.

Parametric study of a concentric coaxial glass tube solar air collector: a theoretical approach

NASA Astrophysics Data System (ADS)

Dabra, Vishal; Yadav, Avadhesh

2017-12-01

Concentric coaxial glass tube solar air collector (CCGTSAC) is a quite innovative development in the field of solar collectors. This type of collector is specially designed to produce hot air. A mathematical model based on the energy conservation equations for small control volumes along the axial direction of concentric coaxial glass tube (CCGT) is developed in this paper. It is applied to predict the effect of thirteen different parameters on the exit air temperature rise and appeared that absorber tube size, length of CCGT, absorptivity of transparent glazing, transmissivity of transparent glazing, absorptivity of absorber coating, inlet or ambient air temperature, mass flow rate, variation of thermo-physical properties of air, wind speed, solar intensity and vacuum present between transparent glazing and absorber tube are significant parameters. Results of the model were analysed to predict the effect of key parameters on the thermal performance of a CCGTSAC for exit air temperature rise about 43.9-58.4 °C.

Aircraft Engine Sump Fire Mitigation

NASA Technical Reports Server (NTRS)

Rosenlieb, J. W.

1973-01-01

An investigation was performed of the conditions in which fires can result and be controlled within the bearing sump simulating that of a gas turbine engine; Esso 4040 Turbo Oil, Mobil Jet 2, and Monsanto MCS-2931 lubricants were used. Control variables include the oil inlet temperature, bearing temperature, oil inlet and scavenge rates, hot air inlet temperature and flow rate, and internal sump baffling. In addition to attempting spontaneous combustion, an electric spark and a rub (friction) mechanism were employed to ignite fires. Spontaneous combustion was not obtained; however, fires were readily ignited with the electric spark while using each of the three test lubricants. Fires were also ignited using the rub mechanism with the only test lubricant evaluated, Esso 4040. Major parameters controlling ignitions were: Sump configuration; Bearing and oil temperatures, hot air temperature and flow and bearing speed. Rubbing between stationary parts and rotating parts (eg. labyrinth seal and mating rub strip) is a very potent fire source suggesting that observed accidental fires in gas turbine sumps may well arise from this cause.

Corneal surface temperature change as the mode of stimulation of the non-contact corneal aesthesiometer.

PubMed

Murphy, P J; Morgan, P B; Patel, S; Marshall, J

1999-05-01

The non-contact corneal aesthesiometer (NCCA) assesses corneal sensitivity by using a controlled pulse of air, directed at the corneal surface. The purpose of this paper was to investigate whether corneal surface temperature change was a component in the mode of stimulation. Thermocouple experiment: A simple model corneal surface was developed that was composed of a moistened circle of filter paper placed on a thermocouple and mounted on a glass slide. The temperature change produced by different stimulus pressures was measured for five different ambient temperatures. Thermal camera experiment: Using a thermal camera, the corneal surface temperature change was measured in nine young, healthy subjects after exposure to different stimulus air pulses. Pulse duration was set at 0.9 s but was varied in pressure from 0.5 to 3.5 millibars. Thermocouple experiment: An immediate drop in temperature was detected by the thermocouple as soon as the air flow was incident on the filter paper. A greater temperature change was produced by increasing the pressure of the incident air flow. A relationship was found and a calibration curve plotted. Thermal camera experiment: For each subject, a drop in surface temperature was detected at each stimulus pressure. Furthermore, as the stimulus pressure increased, the induced reduction in temperature also increased. A relationship was found and a calibration curve plotted. The NCCA air-pulse stimulus was capable of producing a localized temperature change on the corneal surface. The principal mode of corneal nerve stimulation, by the NCCA air pulse, was the rate of temperature change of the corneal surface.

40 CFR 1066.710 - Cold temperature testing procedures for measuring CO and NMHC emissions and determining fuel...

Code of Federal Regulations, 2014 CFR

2014-07-01

... climate control system with the heat on and set to primarily defrost the front window. Turn air.... (i) Prior to the first acceleration, 20 seconds after the start of the UDDS, set the climate control... climate control system): (A) Temperature. Set controls to maximum heat. (B) Fan speed. Set the fan speed...

Thermoregulatory control of finger blood flow

NASA Technical Reports Server (NTRS)

Wenger, C. B.; Roberts, M. F.; Nadel, E. R.; Stolwijk, J. A. J.

1975-01-01

In the present experiment, exercise was used to vary internal temperature and ambient air heat control was used to vary skin temperature. Finger temperature was fixed at about 35.7 C. Esophageal temperature was measured with a thermocouple at the level of the left atrium, and mean skin temperature was calculated from a weighted mean of thermocouple temperatures at different skin sites. Finger blood flow was measured by electrocapacitance plethysmography. An equation in these quantities is given which accounts for the data garnered.

Thermal Management Techniques for Oil-Free Turbomachinery Systems

NASA Technical Reports Server (NTRS)

Radil, Kevin; DellaCorte, Chris; Zeszotek, Michelle

2006-01-01

Tests were performed to evaluate three different methods of utilizing air to provide thermal management control for compliant journal foil air bearings. The effectiveness of the methods was based on bearing bulk temperature and axial thermal gradient reductions during air delivery. The first method utilized direct impingement of air on the inner surface of a hollow test journal during operation. The second, less indirect method achieved heat removal by blowing air inside the test journal to simulate air flowing axially through a hollow, rotating shaft. The third method emulated the most common approach to removing heat by forcing air axially through the bearing s support structure. Internal bearing temperatures were measured with three, type K thermocouples embedded in the bearing that measured general internal temperatures and axial thermal gradients. Testing was performed in a 1 atm, 260 C ambient environment with the bearing operating at 60 krpm and supporting a load of 222 N. Air volumetric flows of 0.06, 0.11, and 0.17 cubic meters per minute at approximately 150 to 200 C were used. The tests indicate that all three methods provide thermal management but at different levels of effectiveness. Axial cooling of the bearing support structure had a greater effect on bulk temperature for each air flow and demonstrated that the thermal gradients could be influenced by the directionality of the air flow. Direct air impingement on the journal's inside surface provided uniform reductions in both bulk temperature and thermal gradients. Similar to the direct method, indirect journal cooling had a uniform cooling effect on both bulk temperatures and thermal gradients but was the least effective of the three methods.

Reduction of the Livestock Ammonia Emission under the Changing Temperature during the Initial Manure Nitrogen Biomineralization

PubMed Central

Bagdonienė, Indrė; Baležentienė, Ligita

2013-01-01

Experimental data were applied for the modelling optimal cowshed temperature environment in laboratory test bench by a mass-flow method. The principal factor affecting exponent growth of ammonia emission was increasing air and manure surface temperature. With the manure temperature increasing from 4°C to 30°C, growth in the ammonia emission grew fourfold, that is, from 102 to 430 mg m−2h−1. Especial risk emerges when temperature exceeds 20°C: an increase in temperature of 1°C contributes to the intensity of ammonia emission by 17 mg m−2h−1. The temperatures of air and manure surface as well as those of its layers are important when analysing emission processes from manure. Indeed, it affects the processes occurring on the manure surface, namely, dehydration and crust formation. To reduce ammonia emission from cowshed, it is important to optimize the inner temperature control and to manage air circulation, especially at higher temperatures, preventing the warm ambient air from blowing direct to manure. Decrease in mean annual temperature of 1°C would reduce the annual ammonia emission by some 5.0%. The air temperature range varied between −15°C and 30°C in barns. The highest mean annual temperature (14.6°C) and ammonia emission (218 mg m−2h−1) were observed in the semideep cowshed. PMID:24453912

Use of Quality Controlled AIRS Temperature Soundings to Improve Forecast Skill

NASA Technical Reports Server (NTRS)

Susskind, Joel; Reale, Oreste; Iredell, Lena

2010-01-01

AIRS was launched on EOS Aqua on May 4, 2002, together with AMSU-A and HSB, to form a next generation polar orbiting infrared and microwave atmospheric sounding system. The primary products of AIRS/AMSU-A are twice daily global fields of atmospheric temperature-humidity profiles, ozone profiles, sea/land surface skin temperature, and cloud related parameters including OLR. Also included are the clear column radiances used to derive these products which are representative of the radiances AIRS would have seen if there were no clouds in the field of view. All products also have error estimates. The sounding goals of AIRS are to produce 1 km tropospheric layer mean temperatures with an rms error of 1K, and layer precipitable water with an rms error of 20 percent, in cases with up to 90 percent effective cloud cover. The products are designed for data assimilation purposes for the improvement of numerical weather prediction, as well as for the study of climate and meteorological processes. With regard to data assimilation, one can use either the products themselves or the clear column radiances from which the products were derived. The AIRS Version 5 retrieval algorithm is now being used operationally at the Goddard DISC in the routine generation of geophysical parameters derived from AIRS/AMSU data. A major innovation in Version 5 is the ability to generate case-by-case level-by-level error estimates for retrieved quantities and clear column radiances, and the use of these error estimates for Quality Control. The temperature profile error estimates are used to determine a case-by-case characteristic pressure pbest, down to which the profile is considered acceptable for data assimilation purposes. The characteristic pressure p(sub best) is determined by comparing the case dependent error estimate (delta)T(p) to the threshold values (Delta)T(p). The AIRS Version 5 data set provides error estimates of T(p) at all levels, and also profile dependent values of pbest based on use of a Standard profile dependent threshold (Delta)T(p). These Standard thresholds were designed as a compromise between optimal use for data assimilation purposes, which requires highest accuracy (tighter Quality Control), and climate purposes, which requires more spatial coverage (looser Quality Control). Subsequent research using Version 5 sounding and error estimates showed that tighter Quality Control performs better for data assimilation proposes, while looser Quality Control better spatial coverage) performs better for climate purposes. We conducted a number of data assimilation experiments using the NASA GEOS-5 Data Assimilation System as a step toward finding an optimum balance of spatial coverage and sounding accuracy with regard to improving forecast skill. The model was run at a horizontal resolution of 0.5 degree latitude x 0.67 degree longitude with 72 vertical levels. These experiments were run during four different seasons, each using a different year. The AIRS temperature profiles were presented to the GEOS-5 analysis as rawinsonde profiles, and the profile error estimates (delta)T(p) were used as the uncertainty for each measurement in the data assimilation process.

Instrumentation enabling study of plant physiological response to elevated night temperature

PubMed Central

Mohammed, Abdul R; Tarpley, Lee

2009-01-01

Background Global climate warming can affect functioning of crops and plants in the natural environment. In order to study the effects of global warming, a method for applying a controlled heating treatment to plant canopies in the open field or in the greenhouse is needed that can accept either square wave application of elevated temperature or a complex prescribed diurnal or seasonal temperature regime. The current options are limited in their accuracy, precision, reliability, mobility or cost and scalability. Results The described system uses overhead infrared heaters that are relatively inexpensive and are accurate and precise in rapidly controlling the temperature. Remote computer-based data acquisition and control via the internet provides the ability to use complex temperature regimes and real-time monitoring. Due to its easy mobility, the heating system can randomly be allotted in the open field or in the greenhouse within the experimental setup. The apparatus has been successfully applied to study the response of rice to high night temperatures. Air temperatures were maintained within the set points ± 0.5°C. The incorporation of the combination of air-situated thermocouples, autotuned proportional integrative derivative temperature controllers and phase angled fired silicon controlled rectifier power controllers provides very fast proportional heating action (i.e. 9 ms time base), which avoids prolonged or intense heating of the plant material. Conclusion The described infrared heating system meets the utilitarian requirements of a heating system for plant physiology studies in that the elevated temperature can be accurately, precisely, and reliably controlled with minimal perturbation of other environmental factors. PMID:19519906

Regenerative air heater

DOEpatents

Hasselquist, P.B.; Baldner, R.

1980-11-26

A gas-cooled steel skirt is used to support a refractory cored brick matrix and dome structure in a high temperature regenerative air heater useful in magnetohydrodynamic power generation. The steel skirt thermally expands to accommodate the thermal expansion of the dome structure despite substantial temperature differential thereby reducing relative movement between the dome bricks. Gas cooling of the steel skirt allows the structure to operate above its normal temperature during clean-out cycles and also allows for the control of the thermal expansion of the steel skirt.

Regenerative air heater

DOEpatents

Hasselquist, Paul B.; Baldner, Richard

1982-01-01

A gas-cooled steel skirt is used to support a refractory cored brick matrix and dome structure in a high temperature regenerative air heater useful in magnetohydrodynamic power generation. The steel skirt thermally expands to accommodate the thermal expansion of the dome structure despite substantial temperature differential thereby reducing relative movement between the dome bricks. Gas cooling of the steel skirt allows the structure to operate above its normal temperature during clean-out cycles and also allows for the control of the thermal expansion of the steel skirt.

Temperature autocontrol system for the coud%eacute; room of the 1.2 m telescope

NASA Astrophysics Data System (ADS)

Zhang, Jian-Hua

The setting up of temperature autocontrol system for the coudé room of the 1.2 m telescope at Yunnan Observatory and realizing the airflow autocirculation, purified the air, keeping the temperature in the coudé room constantly by autocontrol the heater, and then keeping the optical system in the best condition are introduced in this paper. The autocontrol system is designed and developed at the basis of having only the air circulator and the heater controlled by hand.

Controlled simulation of optical turbulence in a temperature gradient air chamber

NASA Astrophysics Data System (ADS)

Toselli, Italo; Wang, Fei; Korotkova, Olga

2016-05-01

Atmospheric turbulence simulator is built and characterized for in-lab optical wave propagation with controlled strength of the refractive-index fluctuations. The temperature gradients are generated by a sequence of heat guns with controlled individual strengths. The temperature structure functions are measured in two directions transverse to propagation path with the help of a thermocouple array and used for evaluation of the corresponding refractive-index structure functions of optical turbulence.

Xylogenesis in black spruce: does soil temperature matter?

PubMed

Lupi, Carlo; Morin, Hubert; Deslauriers, Annie; Rossi, Sergio

2012-01-01

In boreal ecosystems, an increase in soil temperature can stimulate plant growth. However, cambium phenology in trees was better explained by air than soil temperature, which suggested that soil temperature is not the main limiting factor affecting xylogenesis. Since soil temperature and snowmelt are correlated to air temperature, the question whether soil temperature directly limits xylogenesis in the stem will remain unresolved without experiments disentangling air and soil temperatures. This study investigated the effects of an increase of 4 °C in soil temperature and a consequent 1-week earlier snowmelt on growth of black spruce [Picea mariana (Mill.) BSP] in the boreal forest of Quebec, Canada. The soil of two natural stands at different altitudes was warmed up with heating cables during 2008-2010 and cambial phenology and xylem production were monitored weekly from April to October. The results showed no significant effect of the treatment on the phenological phases of cell enlargement and wall thickening and lignification. The number of cells produced in the xylem also did not differ between control and heated trees. These findings allowed the hypothesis of a direct influence of soil temperature on stem growth to be rejected and supported the evidence that, in the short term, air temperature is the main limiting factor for xylogenesis in trees of these environments.

Forest canopy temperatures: dynamics, controls, and relationships with ecosystem fluxes

NASA Astrophysics Data System (ADS)

Still, C. J.; Griffith, D.; Kim, Y.; Law, B. E.; Hanson, C. V.; Kwon, H.; Schulze, M.; Detto, M.; Pau, S.

2017-12-01

Temperature strongly affects enzymatic reactions, ecosystem biogeochemistry, and species distributions. Although most focus is on air temperature, the radiative or skin temperature of plants is more relevant. Canopy skin temperature dynamics reflect biophysical, physiological, and anatomical characteristics and interactions with the environment, and can be used to examine forest responses to stresses like droughts and heat waves. Thermal infrared (TIR) imaging allows for extensive temporal and spatial sampling of canopy temperatures, particularly compared to spot measurements using thermocouples. We present results of TIR imaging of forest canopies at eddy covariance flux tower sites in the US Pacific Northwest and in Panama. These forests range from an old-growth temperate rainforest to a second growth semi-arid pine forest to a semi-deciduous tropical forest. Canopy temperature regimes at these sites are highly variable. Canopy temperatures at all forest sites displayed frequent departures from air temperature, particularly during clear sky conditions, with elevated canopy temperatures during the day and depressed canopy temperatures at night compared to air temperature. Comparison of canopy temperatures to fluxes of carbon dioxide, water vapor, and energy reveals stronger relationships than those found with air temperature. Daytime growing season net ecosystem exchange at the pine forest site is better explained by canopy temperature (r2 = 0.61) than air temperature (r2 = 0.52). At the semi-deciduous tropical forest, canopy photosynthesis is highly correlated with canopy temperature (r2 = 0.51), with a distinct optimum temperature for photosynthesis ( 31 °C) that agrees with leaf-level measurements. During the peak of one heat wave at an old-growth temperate rainforest, hourly averaged air temperature exceeded 35 °C, 10 °C above average. Peak hourly canopy temperature approached 40 °C, and leaf-to-air vapor pressure deficit exceeded 6 kPa. These extreme conditions had a dramatic effect on forest carbon and energy exchanges: the canopy switched from daytime net carbon uptake prior to the heatwave to net carbon release during and immediately after the heat wave. The latent heat flux from evapotranspiration increased during the heat wave, while sensible heat fluxes were lower.

Experimental Determination of Demand Response Control Models and Cost of Control for Ensembles of Window-Mount Air Conditioners

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

Geller, Drew Adam; Backhaus, Scott N.

Control of consumer electrical devices for providing electrical grid services is expanding in both the scope and the diversity of loads that are engaged in control, but there are few experimentally-based models of these devices suitable for control designs and for assessing the cost of control. A laboratory-scale test system is developed to experimentally evaluate the use of a simple window-mount air conditioner for electrical grid regulation services. The experimental test bed is a single, isolated air conditioner embedded in a test system that both emulates the thermodynamics of an air conditioned room and also isolates the air conditioner frommore » the real-world external environmental and human variables that perturb the careful measurements required to capture a model that fully characterizes both the control response functions and the cost of control. The control response functions and cost of control are measured using harmonic perturbation of the temperature set point and a test protocol that further isolates the air conditioner from low frequency environmental variability.« less

System and method for controlling an engine based on ammonia storage in multiple selective catalytic reduction catalysts

DOEpatents

Sun, MIn; Perry, Kevin L.

2015-11-20

A system according to the principles of the present disclosure includes a storage estimation module and an air/fuel ratio control module. The storage estimation module estimates a first amount of ammonia stored in a first selective catalytic reduction (SCR) catalyst and estimates a second amount of ammonia stored in a second SCR catalyst. The air/fuel ratio control module controls an air/fuel ratio of an engine based on the first amount, the second amount, and a temperature of a substrate disposed in the second SCR catalyst.

Analysis of spatial patterns underlying the linkage between solar irradiance and near-surface air temperatures

NASA Astrophysics Data System (ADS)

Balling, Robert C.; Roy, Shouraseni Sen

2005-06-01

Many scientists have noted that global temperature anomalies were highly correlated with solar irradiance values until sometime in the 1970s, but since that time, the pronounced warming in the near-surface temperature record is not explained by variations or trends in solar receipt. In this investigation, spatial dimensions are explored in the relationship between irradiance and near-surface air temperatures. At the scale of individual 5° by 5° grid cells, the solar control on annual temperature variations is not statistically significant. When the temperature data are aggregated by 5° latitudinal bands, the solar - temperature connect is generally significant, and in every band, there is substantial evidence that a non-solar control has become dominant in recent decades. The buildup of greenhouse gases and/or some other global-scale feedback, such as widespread changes in atmospheric water vapor, emerge as potential explanations for the recent residual warming found in all latitudinal bands.

Steam generator on-line efficiency monitor

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

Johnson, R.K.; Kaya, A.; Keyes, M.A. IV

1987-08-04

This patent describes a system for automatically and continuously determining the efficiency of a combustion process in a fossil-fuel fired vapor generator for utilization by an automatic load control system that controls the distribution of a system load among a plurality of vapor generators, comprising: a first function generator, connected to an oxygen transducer for sensing the level of excess air in the flue gas, for generating a first signal indicative of the total air supplied for combustion in percent by weight; a second function generator, connected to a combustibles transducer for sensing the level of combustibles in the fluemore » gas, for generating a second signal indicative of the percent combustibles present in the flue gas; means for correcting the first signal, connected to the first and second function generators, when the oxygen transducer is of a type that operates at a temperature level sufficient to cause the unburned combustibles to react with the oxygen present in the flue gas; an ambient air temperature transducer for generating a third signal indicative of the temperature of the ambient air supplied to the vapor generator for combustion.« less

Air-Powered Projectile Launcher

NASA Technical Reports Server (NTRS)

Andrews, T.; Bjorklund, R. A.; Elliott, D. G.; Jones, L. K.

1987-01-01

Air-powered launcher fires plastic projectiles without using explosive propellants. Does not generate high temperatures. Launcher developed for combat training for U.S. Army. With reservoir pressurized, air launcher ready to fire. When pilot valve opened, sleeve (main valve) moves to rear. Projectile rapidly propelled through barrel, pushed by air from reservoir. Potential applications in seismic measurements, avalanche control, and testing impact resistance of windshields on vehicles.

Two-story residence with solar heating--Newman, Georgia

NASA Technical Reports Server (NTRS)

1981-01-01

Report evaluates performance of warm-air collector system for 11 month period and provides operation and maintenance information. System consists of 14 warm air collectors, rock-storage bin, air handler, heat exchangers, hot-water preheat tank, associated controls, plumbing, and air ducting. Average building temperature was maintained at 72 F (22 C); solar equipment provided 47 percent of space-heating requirement.

Observations of the microclimate of a lake under cold air advective conditions

NASA Technical Reports Server (NTRS)

Bill, R. G., Jr.; Sutherland, R. A.; Bartholic, J. F.

1977-01-01

The moderating effects of Lake Apopka, Florida, on downwind surface temperatures were evaluated under cold air advective conditions. Point temperature measurements north and south of the lake and data obtained from the NOAA satellite and a thermal scanner flown at 1.6 km, indicate that, under conditions of moderate winds (approximately 4m/sec), surface temperatures directly downwind may be higher than surrounding surface temperatures by as much as 5 C. With surface wind speed less than 1m/sec, no substantial temperature effects were observed. Results of this study are being used in land use planning, lake level control and in agriculture for selecting planting sites.

Continuous measurement of air-water gas exchange by underwater eddy covariance

NASA Astrophysics Data System (ADS)

Berg, Peter; Pace, Michael L.

2017-12-01

Exchange of gases, such as O2, CO2, and CH4, over the air-water interface is an important component in aquatic ecosystem studies, but exchange rates are typically measured or estimated with substantial uncertainties. This diminishes the precision of common ecosystem assessments associated with gas exchanges such as primary production, respiration, and greenhouse gas emission. Here, we used the aquatic eddy covariance technique - originally developed for benthic O2 flux measurements - right below the air-water interface (˜ 4 cm) to determine gas exchange rates and coefficients. Using an acoustic Doppler velocimeter and a fast-responding dual O2-temperature sensor mounted on a floating platform the 3-D water velocity, O2 concentration, and temperature were measured at high-speed (64 Hz). By combining these data, concurrent vertical fluxes of O2 and heat across the air-water interface were derived, and gas exchange coefficients were calculated from the former. Proof-of-concept deployments at different river sites gave standard gas exchange coefficients (k600) in the range of published values. A 40 h long deployment revealed a distinct diurnal pattern in air-water exchange of O2 that was controlled largely by physical processes (e.g., diurnal variations in air temperature and associated air-water heat fluxes) and not by biological activity (primary production and respiration). This physical control of gas exchange can be prevalent in lotic systems and adds uncertainty to assessments of biological activity that are based on measured water column O2 concentration changes. For example, in the 40 h deployment, there was near-constant river flow and insignificant winds - two main drivers of lotic gas exchange - but we found gas exchange coefficients that varied by several fold. This was presumably caused by the formation and erosion of vertical temperature-density gradients in the surface water driven by the heat flux into or out of the river that affected the turbulent mixing. This effect is unaccounted for in widely used empirical correlations for gas exchange coefficients and is another source of uncertainty in gas exchange estimates. The aquatic eddy covariance technique allows studies of air-water gas exchange processes and their controls at an unparalleled level of detail. A finding related to the new approach is that heat fluxes at the air-water interface can, contrary to those typically found in the benthic environment, be substantial and require correction of O2 sensor readings using high-speed parallel temperature measurements. Fast-responding O2 sensors are inherently sensitive to temperature changes, and if this correction is omitted, temperature fluctuations associated with the turbulent heat flux will mistakenly be recorded as O2 fluctuations and bias the O2 eddy flux calculation.

Improved spatial monitoring of air temperature in forested complex terrain: an energy-balance based calibration method

NASA Astrophysics Data System (ADS)

Kennedy, A. M.; Thomas, C. K.; Pypker, T. G.; Bond, B. J.; Selker, J. S.; Unsworth, M. H.

2009-12-01

Fiber-optic distributed temperature sensing (DTS) has great potential for spatial monitoring in hydrology and atmospheric science. DTS systems have an advantage over conventional individual temperature sensors in that thousands of quasi-concurrent temperature measurements may be made along the entire length of a fiber at 1 meter increments by a single instrument, thus increasing measurement precision. However, like any other temperature sensors, the fiber temperature is influenced by energy exchange with its environment, particularly by radiant energy (solar and long-wave) and by wind speed. The objective of this research is to perform an energy-balance based calibration of a DTS fiber system that will reduce the uncertainty of air temperature measurements in open and forested environments. To better understand the physics controlling the fiber temperature reported by the DTS, alternating black and white fiber optic cables were installed on vertical wooden jigs inside a recirculating wind tunnel. A constant irradiance from six 600W halogen lamps was directed on a two meter section of fiber to permit controlled observations of the resulting temperature difference between the black and white fibers as wind speed was varied. The net short and longwave radiation balance of each fiber was measured with an Eppley pyranometer and Kipp and Zonen pyrgeometer. Additionally, accurate air temperature was recorded from a screened platinum resistance thermometer, and sonic anemometers were positioned to record wind speed and turbulence. Relationships between the temperature excess of each fiber, net radiation, and wind speed were developed and will be used to derive correction terms in future field work. Preliminary results indicate that differential heating of fibers (black-white) is driven largely by net radiation with wind having a smaller but consistent effect. Subsequent work will require field verification to confirm that the observed wind tunnel correction algorithms are applicable in both open and forest canopy settings. Our ultimate goal is to use atmospheric DTS measurements of 3D temperature fields in a small steep-walled forested watershed to gain a better understanding and rigorous description of the processes governing air circulation (cold air drainage etc) in the canopy. Such knowledge will assist in the interpretation of observed biological responses.

Increasing EDV Range through Intelligent Cabin Air Handling Strategies: Annual Progress Report

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

Leighton, Daniel; Rugh, John

Computational fluid dynamics (CFD) simulations of a Ford Focus Electric demonstrated that a split flow heating, ventilating and air conditioning (HVAC) system with rear recirculation ducts can reduce cabin heating loads by up to 57.4% relative to full fresh air usage under some conditions (steady state, four passengers, ambient temperature of -5 deg C). Simulations also showed that implementing a continuous recirculation fraction control system into the original equipment manufacturer (OEM) HVAC system can reduce cabin heating loads by up to 50.0% relative to full fresh air usage under some conditions (steady state, four passengers, ambient temperature of -5 degmore » C). Identified that continuous fractional recirculation control of the OEM system can provide significant energy savings for EVs at minimal additional cost, while a split flow HVAC system with rear recirculation ducts only provides minimal additional improvement at significant additional cost.« less

Feedback linearization based control of a variable air volume air conditioning system for cooling applications.

PubMed

Thosar, Archana; Patra, Amit; Bhattacharyya, Souvik

2008-07-01

Design of a nonlinear control system for a Variable Air Volume Air Conditioning (VAVAC) plant through feedback linearization is presented in this article. VAVAC systems attempt to reduce building energy consumption while maintaining the primary role of air conditioning. The temperature of the space is maintained at a constant level by establishing a balance between the cooling load generated in the space and the air supply delivered to meet the load. The dynamic model of a VAVAC plant is derived and formulated as a MIMO bilinear system. Feedback linearization is applied for decoupling and linearization of the nonlinear model. Simulation results for a laboratory scale plant are presented to demonstrate the potential of keeping comfort and maintaining energy optimal performance by this methodology. Results obtained with a conventional PI controller and a feedback linearizing controller are compared and the superiority of the proposed approach is clearly established.

Environmental Systems Test Stand

NASA Astrophysics Data System (ADS)

Barta, D.; Young, J.; Ewert, M.; Lee, S.; Wells, P.; Fortson, R.; Castillo, J.

A test stand has been developed for the evaluation of prototype lighting, environmental control and crop cultivation technologies for plant production within an advanced life support system. Design of the test stand was based on preliminary designs of the center growth bay of the Biomass Production Chamber, one of several modules of the Bioregenerative Planetary Life Support Systems Test Complex (BIO- Plex). It consists of two controlled-environment shelves, each with 4.7 m2 of area for crop growth (150 cm width, 315 cm length). There are two chilled water loops, one for operation at conventional temperatures (5-10C) for air temperature and humidity control and one for operation at higher temperatures (15-50C) for waste heat acquisition and heating. Modular light boxes, utilizing either air-cooled or water- jacketed HPS lamps, have been developed. This modular design will allow for easy replacement of new lighting technologies within the light banks. An advanced data acquisition and control system has been developed utilizing localized, networked- based data acquisition modules and programmed with object-based control software.

Eight Year Climatologies from Observational (AIRS) and Model (MERRA) Data

NASA Technical Reports Server (NTRS)

Hearty, Thomas; Savtchenko, Andrey; Won, Young-In; Theobalk, Mike; Vollmer, Bruce; Manning, Evan; Smith, Peter; Ostrenga, Dana; Leptoukh, Greg

2010-01-01

We examine climatologies derived from eight years of temperature, water vapor, cloud, and trace gas observations made by the Atmospheric Infrared Sounder (AIRS) instrument flying on the Aqua satellite and compare them to similar climatologies constructed with data from a global assimilation model, the Modern Era Retrospective-Analysis for Research and Applications (MERRA). We use the AIRS climatologies to examine anomalies and trends in the AIRS data record. Since sampling can be an issue for infrared satellites in low earth orbit, we also use the MERRA data to examine the AIRS sampling biases. By sampling the MERRA data at the AIRS space-time locations both with and without the AIRS quality control we estimate the sampling bias of the AIRS climatology and the atmospheric conditions where AIRS has a lower sampling rate. While the AIRS temperature and water vapor sampling biases are small at low latitudes, they can be more than a few degrees in temperature or 10 percent in water vapor at higher latitudes. The largest sampling biases are over desert. The AIRS and MERRA data are available from the Goddard Earth Sciences Data and Information Services Center (GES DISC). The AIRS climatologies we used are available for analysis with the GIOVANNI data exploration tool. (see, http://disc.gsfc.nasa.gov).

IR thermocycler for centrifugal microfluidic platform with direct on-disk wireless temperature measurement system

NASA Astrophysics Data System (ADS)

Burger, J.; Gross, A.; Mark, D.; Roth, G.; von Stetten, F.; Zengerle, R.

2011-06-01

The direct on-disk wireless temperature measurement system [1,2] presented at μTAS 2010 was further improved in its robustness. We apply it to an IR thermocycler as part of a centrifugal microfluidic analyzer for polymerase chain reactions (PCR). This IR thermocycler allows the very efficient direct heating of aqueous liquids in microfluidic cavities by an IR radiation source. The efficiency factor of this IR heating system depends on several parameters. First there is the efficiency of the IR radiator considering the transformation of electrical energy into radiation energy. This radiation energy needs to be focused by a reflector to the center of the cavity. Both, the reflectors shape and the quality of the reflecting layer affect the efficiency. On the way to the center of the cavity the radiation energy will be diminished by absorption in the surrounding air/humidity and especially in the cavity lid of the microfluidic disk. The transmission spectrum of the lid material and its thickness is of significant impact. We chose a COC polymer film with a thickness of 150 μm. At a peak frequency of the IR radiator of ~2 μm approximately 85 % of the incoming radiation energy passes the lid and is absorbed within the first 1.5 mm depth of liquid in the cavity. As we perform the thermocycling for a PCR, after heating to the denaturation temperature of ~ 92 °C we need to cool down rapidly to the primer annealing temperature of ~ 55 °C. Cooling is realized by 3 ventilators venting air of room temperature into the disk chamber. Due to the air flow itself and an additional rotation of the centrifugal microfluidic disk the PCR reagents in the cavities are cooled by forced air convection. Simulation studies based upon analogous electrical models enable to optimize the disk geometry and the optical path. Both the IR heater and the ventilators are controlled by the digital PID controller HAPRO 0135 [3]. The sampling frequency is set to 2 Hz. It could be further increased up to a maximum value being permitted by the wireless temperature data transmission system. As we are controlling a significantly non-linear process the controller parameters need to be optimized for all temperatures relevant for the PCR thermocycling process. Such we get a dynamic system for both, the heating and the cooling process. Heating rates up to 5 K/s with our IR heater (100 W electrical power) could be achieved. Cooling rates of instantly 1.3 K/s at 20 Hz rotation frequency could be even further increased by higher rotation frequencies, faster air circulation, optimization of the controller parameters or an active air cooling unit.

Robustness analysis of an air heating plant and control law by using polynomial chaos

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

Colón, Diego; Ferreira, Murillo A. S.; Bueno, Átila M.

2014-12-10

This paper presents a robustness analysis of an air heating plant with a multivariable closed-loop control law by using the polynomial chaos methodology (MPC). The plant consists of a PVC tube with a fan in the air input (that forces the air through the tube) and a mass flux sensor in the output. A heating resistance warms the air as it flows inside the tube, and a thermo-couple sensor measures the air temperature. The plant has thus two inputs (the fan's rotation intensity and heat generated by the resistance, both measured in percent of the maximum value) and two outputsmore » (air temperature and air mass flux, also in percent of the maximal value). The mathematical model is obtained by System Identification techniques. The mass flux sensor, which is nonlinear, is linearized and the delays in the transfer functions are properly approximated by non-minimum phase transfer functions. The resulting model is transformed to a state-space model, which is used for control design purposes. The multivariable robust control design techniques used is the LQG/LTR, and the controllers are validated in simulation software and in the real plant. Finally, the MPC is applied by considering some of the system's parameters as random variables (one at a time, and the system's stochastic differential equations are solved by expanding the solution (a stochastic process) in an orthogonal basis of polynomial functions of the basic random variables. This method transforms the stochastic equations in a set of deterministic differential equations, which can be solved by traditional numerical methods (That is the MPC). Statistical data for the system (like expected values and variances) are then calculated. The effects of randomness in the parameters are evaluated in the open-loop and closed-loop pole's positions.« less

Analysis of Heat Stress and the Indoor Climate Control Requirements for Movable Refuge Chambers

PubMed Central

Hao, Xiaoli; Guo, Chenxin; Lin, Yaolin; Wang, Haiqiao; Liu, Heqing

2016-01-01

Movable refuge chambers are a new kind of rescue device for underground mining, which is believed to have a potential positive impact on reducing the rate of fatalities. It is likely to be hot and humid inside a movable refuge chamber due to the metabolism of trapped miners, heat generated by equipment and heat transferred from outside. To investigate the heat stress experienced by miners trapped in a movable refuge chamber, the predicted heat strain (PHS) model was used to simulate the heat transfer process between the person and the thermal environment. The variations of heat stress with the temperature and humidity inside the refuge chamber were analyzed. The effects of air temperature outside the refuge chamber and the overall heat transfer coefficient of the refuge chamber shell on the heat stress inside the refuge chamber was also investigated. The relationship between the limit of exposure duration and the air temperature and humidity was numerically analyzed to determine the upper limits of temperature and humidity inside a refuge chamber. Air temperature of 32 °C and relative humidity of 70% are recommended as the design standard for internal thermal environment control of movable refuge chambers. PMID:27213422

Analysis of Heat Stress and the Indoor Climate Control Requirements for Movable Refuge Chambers.

PubMed

Hao, Xiaoli; Guo, Chenxin; Lin, Yaolin; Wang, Haiqiao; Liu, Heqing

2016-05-20

Movable refuge chambers are a new kind of rescue device for underground mining, which is believed to have a potential positive impact on reducing the rate of fatalities. It is likely to be hot and humid inside a movable refuge chamber due to the metabolism of trapped miners, heat generated by equipment and heat transferred from outside. To investigate the heat stress experienced by miners trapped in a movable refuge chamber, the predicted heat strain (PHS) model was used to simulate the heat transfer process between the person and the thermal environment. The variations of heat stress with the temperature and humidity inside the refuge chamber were analyzed. The effects of air temperature outside the refuge chamber and the overall heat transfer coefficient of the refuge chamber shell on the heat stress inside the refuge chamber was also investigated. The relationship between the limit of exposure duration and the air temperature and humidity was numerically analyzed to determine the upper limits of temperature and humidity inside a refuge chamber. Air temperature of 32 °C and relative humidity of 70% are recommended as the design standard for internal thermal environment control of movable refuge chambers.

24-HOUR DIFFUSIVE SAMPLING OF TOXIC VOCS IN AIR ONTO CARBOPACK X SOLID ADSORBENT FOLLOWED BY THERMAL DESORPTION/GC/MS ANALYSIS - LABORATORY STUDIES

EPA Science Inventory

Diffusive sampling of a mixture of 42 volatile organic compounds (VOCs) in humidified, purified air onto the solid adsorbent Carbopack X was evaluated under controlled laboratory conditions. The evaluation included variations in sample air temperature, relative humidity, and ozon...

Design of modular control system for grain dryers

NASA Astrophysics Data System (ADS)

He, Gaoqing; Liu, Yanhua; Zu, Yuan

In order to effectively control the temperature of grain drying bin, grain ,air outlet as well as the grain moisture, it designed the control system of 5HCY-35 which is based on MCU to adapt to all grains drying conditions, high drying efficiency, long life usage and less manually. The system includes: the control module of the constant temperature and the temperature difference control in drying bin, the constant temperature control of heating furnace, on-line testing of moisture, variety of grain-circulation speed control and human-computer interaction interface. Spatial curve simulation, which takes moisture as control objectives, controls the constant temperature and the temperature difference in drying bin according to preset parameter by the user or a list to reduce the grains explosive to ensure the seed germination percentage. The system can realize the intelligent control of high efficiency and various drying, the good scalability and the high quality.

Numerical analysis for temperature profile of the closed house using computational fluid dynamics

NASA Astrophysics Data System (ADS)

Setiadi, Rizki; Munadi, Tauviqirrahman, Mohammad

2018-03-01

This study aims to analyze the air temperature distribution in the closed house system for broiler using ABAQUS CFD Model. The obtained data is used for placing the temperature sensor before making the control system for the closed house. The dimesion of the experimental house was 30 m × 12 m × 2 m (length × width × height) which could be occupied by 7.500 broiler. The wall was made from expose mercy brick and curtain, ventilation system used 7 exhaust fan with diameter 1 m and 2 cooling unit, the roof was made from wood, and system used 45 of 7 watt lamp. The results of the analysis show that temperature distribution occurs on temperature 21-33.5°C and still relatively comfortable for broiler at the age of 1-21days. The air temperature distribution near the cooling unit is lower and increases to near the exhaust fan. In addition, the air temperature in the area near the roof is more high than others.

Development of Fault Models for Hybrid Fault Detection and Diagnostics Algorithm: October 1, 2014 -- May 5, 2015

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

Cheung, Howard; Braun, James E.

This report describes models of building faults created for OpenStudio to support the ongoing development of fault detection and diagnostic (FDD) algorithms at the National Renewable Energy Laboratory. Building faults are operating abnormalities that degrade building performance, such as using more energy than normal operation, failing to maintain building temperatures according to the thermostat set points, etc. Models of building faults in OpenStudio can be used to estimate fault impacts on building performance and to develop and evaluate FDD algorithms. The aim of the project is to develop fault models of typical heating, ventilating and air conditioning (HVAC) equipment inmore » the United States, and the fault models in this report are grouped as control faults, sensor faults, packaged and split air conditioner faults, water-cooled chiller faults, and other uncategorized faults. The control fault models simulate impacts of inappropriate thermostat control schemes such as an incorrect thermostat set point in unoccupied hours and manual changes of thermostat set point due to extreme outside temperature. Sensor fault models focus on the modeling of sensor biases including economizer relative humidity sensor bias, supply air temperature sensor bias, and water circuit temperature sensor bias. Packaged and split air conditioner fault models simulate refrigerant undercharging, condenser fouling, condenser fan motor efficiency degradation, non-condensable entrainment in refrigerant, and liquid line restriction. Other fault models that are uncategorized include duct fouling, excessive infiltration into the building, and blower and pump motor degradation.« less

Development of Fault Models for Hybrid Fault Detection and Diagnostics Algorithm: October 1, 2014 -- May 5, 2015

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

Cheung, Howard; Braun, James E.

2015-12-31

This report describes models of building faults created for OpenStudio to support the ongoing development of fault detection and diagnostic (FDD) algorithms at the National Renewable Energy Laboratory. Building faults are operating abnormalities that degrade building performance, such as using more energy than normal operation, failing to maintain building temperatures according to the thermostat set points, etc. Models of building faults in OpenStudio can be used to estimate fault impacts on building performance and to develop and evaluate FDD algorithms. The aim of the project is to develop fault models of typical heating, ventilating and air conditioning (HVAC) equipment inmore » the United States, and the fault models in this report are grouped as control faults, sensor faults, packaged and split air conditioner faults, water-cooled chiller faults, and other uncategorized faults. The control fault models simulate impacts of inappropriate thermostat control schemes such as an incorrect thermostat set point in unoccupied hours and manual changes of thermostat set point due to extreme outside temperature. Sensor fault models focus on the modeling of sensor biases including economizer relative humidity sensor bias, supply air temperature sensor bias, and water circuit temperature sensor bias. Packaged and split air conditioner fault models simulate refrigerant undercharging, condenser fouling, condenser fan motor efficiency degradation, non-condensable entrainment in refrigerant, and liquid line restriction. Other fault models that are uncategorized include duct fouling, excessive infiltration into the building, and blower and pump motor degradation.« less

Controls of air temperature variability over an Alpine Glacier

NASA Astrophysics Data System (ADS)

Shaw, Thomas; Brock, Ben; Ayala, Álvaro; Rutter, Nick

2016-04-01

Near surface air temperature (Ta) is one of the most important controls on energy exchange between a glacier surface and the overlying atmosphere. However, not enough detail is known about the controls on Ta across a glacier due to sparse data availability. Recent work has provided insights into variability of Ta along glacier centre-lines in different parts of the world, yet there is still a limited understanding of off-centreline variability in Ta and how best to estimate it from distant off-glacier locations. We present a new dataset of distributed 2m Ta records for the Tsanteleina Glacier in Northwest Italy from July-September, 2015. Data provide detailed information of lateral (across-glacier) and centre-line variations in Ta, with ~20,000 hourly observations from 17 locations. The suitability of different vertical temperature gradients (VTGs) in estimating air temperature is considered under a range of meteorological conditions and from different forcing locations. A key finding is that local VTGs account for a lot of Ta variability under a broad range of climatic conditions. However, across-glacier variability is found to be significant, particularly for high ambient temperatures and for localised topographic depressions. The relationship of spatial Ta patterns with regional-scale reanalysis data and alternative Ta estimation methodologies are also presented. This work improves the knowledge of local scale Ta variations and their importance to melt modelling.

Development of automated control system for wood drying

NASA Astrophysics Data System (ADS)

Sereda, T. G.; Kostarev, S. N.

2018-05-01

The article considers the parameters of convective wood drying which allows changing the characteristics of the air that performs drying at different stages: humidity, temperature, speed and direction of air movement. Despite the prevalence of this type of drying equipment, the main drawbacks of it are: the high temperature and humidity, negatively affecting the working conditions of maintenance personnel when they enter the drying chambers. It makes the automation of wood drying process necessary. The synthesis of a finite state of a machine control of wood drying process is implemented on a programmable logic device Omron.

Active Combustion Control for Aircraft Gas Turbine Engines

NASA Technical Reports Server (NTRS)

DeLaat, John C.; Breisacher, Kevin J.; Saus, Joseph R.; Paxson, Daniel E.

2000-01-01

Lean-burning combustors are susceptible to combustion instabilities. Additionally, due to non-uniformities in the fuel-air mixing and in the combustion process, there typically exist hot areas in the combustor exit plane. These hot areas limit the operating temperature at the turbine inlet and thus constrain performance and efficiency. Finally, it is necessary to optimize the fuel-air ratio and flame temperature throughout the combustor to minimize the production of pollutants. In recent years, there has been considerable activity addressing Active Combustion Control. NASA Glenn Research Center's Active Combustion Control Technology effort aims to demonstrate active control in a realistic environment relevant to aircraft engines. Analysis and experiments are tied to aircraft gas turbine combustors. Considerable progress has been shown in demonstrating technologies for Combustion Instability Control, Pattern Factor Control, and Emissions Minimizing Control. Future plans are to advance the maturity of active combustion control technology to eventual demonstration in an engine environment.

Changes in canopy cover alter surface air and forest floor temperature in a high-elevation red spruce (Picea rubens Sarg.) forest

Treesearch

Johnny L. Boggs; Steven G. McNulty

2010-01-01

The objective of this study is to describe winter and summer surface air and forest floor temperature patterns and diurnal fluctuations in high-elevation red spruce (Picea rubens Sarg.) forests with different levels of canopy cover. In 1988, a series of 10- x 10-meter plots (control, low nitrogen [N] addition, and high nitrogen addition) were...

31. View of mezzanine floor level in transmitter building no. ...

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

31. View of mezzanine floor level in transmitter building no. 102 showing various electronic central indicator panel to control building air conditioning, steam pressure, supply temperature, discharge temperature, supply pressure, transformer vault status, and radome conditioning system. - Clear Air Force Station, Ballistic Missile Early Warning System Site II, One mile west of mile marker 293.5 on Parks Highway, 5 miles southwest of Anderson, Anderson, Denali Borough, AK

Feasibility of Reburning for Controlling NOx Emissions from Air Force Jet Engine Test Cells

DTIC Science & Technology

1989-06-01

the engine exhaust by the augmenter air. For this reason, it is important to examine the effect of inlet NOX concentration on achieved reduction...Schedule at Tinker AFB .... ......... 8 3 Typical Nonafterburning Turbine Engine Emission Trends. . 9 4 Temperature of Diluted Exhaust J-79 Engine ... Exhaust Temperature on Reburner NOX Reduction .......... ......................... . 43 24 Effect of Exhaust Gas Inlet Flow Rate on Reburner NOx

Air temperature sensors: dependence of radiative errors on sensor diameter in precision metrology and meteorology

NASA Astrophysics Data System (ADS)

de Podesta, Michael; Bell, Stephanie; Underwood, Robin

2018-04-01

In both meteorological and metrological applications, it is well known that air temperature sensors are susceptible to radiative errors. However, it is not widely known that the radiative error measured by an air temperature sensor in flowing air depends upon the sensor diameter, with smaller sensors reporting values closer to true air temperature. This is not a transient effect related to sensor heat capacity, but a fluid-dynamical effect arising from heat and mass flow in cylindrical geometries. This result has been known historically and is in meteorology text books. However, its significance does not appear to be widely appreciated and, as a consequence, air temperature can be—and probably is being—widely mis-estimated. In this paper, we first review prior descriptions of the ‘sensor size’ effect from the metrological and meteorological literature. We develop a heat transfer model to describe the process for cylindrical sensors, and evaluate the predicted temperature error for a range of sensor sizes and air speeds. We compare these predictions with published predictions and measurements. We report measurements demonstrating this effect in two laboratories at NPL in which the air flow and temperature are exceptionally closely controlled. The results are consistent with the heat-transfer model, and show that the air temperature error is proportional to the square root of the sensor diameter and that, even under good laboratory conditions, it can exceed 0.1 °C for a 6 mm diameter sensor. We then consider the implications of this result. In metrological applications, errors of the order of 0.1 °C are significant, representing limiting uncertainties in dimensional and mass measurements. In meteorological applications, radiative errors can easily be much larger. But in both cases, an understanding of the diameter dependence allows assessment and correction of the radiative error using a multi-sensor technique.

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.

40 CFR 1036.801 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... control device means any element of design that senses temperature, motive speed, engine RPM, transmission.... Emission control system means any device, system, or element of design that controls or reduces the... Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF...

40 CFR 1036.801 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-07-01

... control device means any element of design that senses temperature, motive speed, engine RPM, transmission.... Emission control system means any device, system, or element of design that controls or reduces the... Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF...

Phosphor thermometry system

DOEpatents

Beshears, David L.; Sitter, Jr., David N.; Andrews, William H.; Simpson, Marc L.; Abston, Ruth A.; Cates, Michael R.; Allison, Steve W.

2000-01-01

An apparatus for measuring the temperature of a moving substrate includes an air gun with a powder inlet port in communication with the outlet port of a powder reservoir, an air inlet port in communication with a pressurized air source, and an outlet nozzle spaced from and directed toward the moving substrate. The air gun is activated by the air pulses to spray controlled amounts of the powdered phosphor onto the moving substrate, where the phosphor assumes the temperature of the moving substrate. A laser produces light pulses, and optics direct the light pulses onto the phosphor on the moving substrate, in response to which the phosphor emits a luminescence with a decay rate indicative of the temperature of the phosphor. A collection lens is disposed to focus the luminescence, and a photodetector detects the luminescence focused by the collection lens and produces an electrical signal that is characteristic of the brightness of the luminescence. A processor analyzes the electrical signal to determine the decay characteristic of the luminescence and to determine the temperature of the phosphor from the decay characteristic.

Variable Temperature Equipment for a Commercial Magnetic Susceptibility Balance

ERIC Educational Resources Information Center

Lotz, Albert

2008-01-01

Variable temperature equipment for the magnetic susceptibility balance MSB-MK1 of Sherwood Scientific, Ltd., is described. The sample temperature is controlled with streaming air heated by water in a heat exchanger. Whereas the balance as sold commercially can be used only for room temperature measurements, the setup we designed extends the…

Near-continuous thermal monitoring of a diverse tropical forest canopy

NASA Astrophysics Data System (ADS)

Pau, S.; Still, C. J.; Kim, Y.; Detto, M.

2015-12-01

Tropical species may be highly sensitive to temperature increases associated with climate change because of their narrow thermal tolerances. Recent work has highlighted the importance of temperature in tropical forest function, however most studies use air temperature measurements from sparse meteorological stations even though surface temperatures are known to deviate from air temperatures. Tropical organisms exist in microclimates that are highly variable in space and time and not easily measured in natural environments. This is in part because of the complex structure of tropical forests and the potential for organisms themselves to modify their own environment. In the case of plants, leaf temperature is linked to the water and surface energy balance of their microenvironment. Here we present results from near-continuous thermal camera monitoring of the forest canopy in Barro Colorado Island, Panama (5-minute intervals for approximately 9 months). We compare daytime (maximum) vs. nighttime (minimum) differences between canopy temperature and air temperature, relative humidity, solar radiation, and precipitation. On average, canopy temperatures are consistently ~2 degrees Celsius higher than air temperatures. These data can paired with flux tower data on-site and used to advance understanding of temperature controls on the structure and function of tropical forests, such as carbon assimilation, phenology, and habitat monitoring, and can be integrated into models to improve predictions of tropical forest response to future climate change.

Effect of high environmental temperature on semen parameters among fertile men.

PubMed

Momen, M Nabil; Ananian, Fredrick B; Fahmy, Ibrahim M; Mostafa, Taymour

2010-04-01

To evaluate the effect of high environmental occupational temperature on semen parameters of fertile men. Prospective. Steel-casting plant. Ninety fertile workers exposed to a high temperature compared with 40 fertile workers working under ordinary conditions as control subjects. Measurement of scrotal temperature by invagination thermometry, air temperature, relative humidity by aspirated psychrometer, radiant heat by globe thermometer, air velocity by light vane anemometer, and semen analysis. Scrotal temperature and semen analysis. Nonsignificant difference was found between the two groups regarding their scrotal temperature. Also, nonsignificant differences were demonstrated regarding semen analysis parameters being in the normozoospermic range. Under high environmental temperature, semen parameters were within normozoospermic levels owing to body acclimatization mechanisms. Copyright 2010 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

Short-term airing by natural ventilation - implication on IAQ and thermal comfort.

PubMed

Heiselberg, P; Perino, M

2010-04-01

The need to improve the energy efficiency of buildings requires new and more efficient ventilation systems. It has been demonstrated that innovative operating concepts that make use of natural ventilation seem to be more appreciated by occupants. Among the available ventilation strategies that are currently available, buoyancy driven, single-sided natural ventilation has proved to be very effective and can provide high air change rates for temperature and Indoor Air Quality (IAQ) control. However, to promote a wider distribution of these systems an improvement in the knowledge of their working principles is necessary. The present study analyses and presents the results of an experimental evaluation of airing performance in terms of ventilation characteristics, IAQ and thermal comfort. It includes investigations of the consequences of opening time, opening frequency, opening area and expected airflow rate, ventilation efficiency, thermal comfort and dynamic temperature conditions. A suitable laboratory test rig was developed to perform extensive experimental analyses of the phenomenon under controlled and repeatable conditions. The results showed that short-term window airing is very effective and can provide both acceptable IAQ and thermal comfort conditions in buildings. Practical Implications This study gives the necessary background and in-depth knowledge of the performance of window airing by single-sided natural ventilation necessary for the development of control strategies for window airing (length of opening period and opening frequency) for optimum IAQ and thermal comfort in naturally ventilated buildings.

Combustor for fine particulate coal

DOEpatents

Carlson, L.W.

1988-01-26

A particulate coal combustor with two combustion chambers is provided. The first combustion chamber is toroidal; air and fuel are injected, mixed, circulated and partially combusted. The air to fuel ratio is controlled to avoid production of soot or nitrogen oxides. The mixture is then moved to a second combustion chamber by injection of additional air where combustion is completed and ash removed. Temperature in the second chamber is controlled by cooling and gas mixing. The clean stream of hot gas is then delivered to a prime mover. 4 figs.

Combustor for fine particulate coal

DOEpatents

Carlson, Larry W.

1988-01-01

A particulate coal combustor with two combustion chambers is provided. The first combustion chamber is toroidal; air and fuel are injected, mixed, circulated and partially combusted. The air to fuel ratio is controlled to avoid production of soot or nitrogen oxides. The mixture is then moved to a second combustion chamber by injection of additional air where combustion is completed and ash removed. Temperature in the second chamber is controlled by cooling and gas mixing. The clean stream of hot gas is then delivered to a prime mover.

Combustor for fine particulate coal

DOEpatents

Carlson, L.W.

1988-11-08

A particulate coal combustor with two combustion chambers is provided. The first combustion chamber is toroidal; air and fuel are injected, mixed, circulated and partially combusted. The air to fuel ratio is controlled to avoid production of soot or nitrogen oxides. The mixture is then moved to a second combustion chamber by injection of additional air where combustion is completed and ash removed. Temperature in the second chamber is controlled by cooling and gas mixing. The clean stream of hot gas is then delivered to a prime mover. 4 figs.

40 CFR 1042.901 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-07-01

... part. Auxiliary emission control device means any element of design that senses temperature, vessel..., system, or element of design that controls or reduces the emissions of regulated pollutants from an... Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF...

40 CFR 1042.901 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... part. Auxiliary emission control device means any element of design that senses temperature, vessel..., system, or element of design that controls or reduces the emissions of regulated pollutants from an... Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF...

40 CFR 1042.901 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... part. Auxiliary emission control device means any element of design that senses temperature, vessel..., system, or element of design that controls or reduces the emissions of regulated pollutants from an... Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF...

40 CFR 1042.901 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... part. Auxiliary emission control device means any element of design that senses temperature, vessel..., system, or element of design that controls or reduces the emissions of regulated pollutants from an... Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF...

40 CFR 1037.801 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-07-01

.... Auxiliary emission control device means any element of design that senses temperature, motive speed, engine... any device, system, or element of design that controls or reduces the emissions of regulated... Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF...

40 CFR 1037.801 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-07-01

.... Auxiliary emission control device means any element of design that senses temperature, motive speed, engine... any device, system, or element of design that controls or reduces the emissions of regulated... Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF...

40 CFR 1042.901 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-07-01

... part. Auxiliary emission control device means any element of design that senses temperature, vessel..., system, or element of design that controls or reduces the emissions of regulated pollutants from an... Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF...

Improved Temperature Sounding and Quality Control Methodology Using AIRS/AMSU Data: The AIRS Science Team Version 5 Retrieval Algorithm

NASA Technical Reports Server (NTRS)

Susskind, Joel; Blaisdell, John M.; Iredell, Lena; Keita, Fricky

2009-01-01

This paper describes the AIRS Science Team Version 5 retrieval algorithm in terms of its three most significant improvements over the methodology used in the AIRS Science Team Version 4 retrieval algorithm. Improved physics in Version 5 allows for use of AIRS clear column radiances in the entire 4.3 micron CO2 absorption band in the retrieval of temperature profiles T(p) during both day and night. Tropospheric sounding 15 micron CO2 observations are now used primarily in the generation of clear column radiances .R(sub i) for all channels. This new approach allows for the generation of more accurate values of .R(sub i) and T(p) under most cloud conditions. Secondly, Version 5 contains a new methodology to provide accurate case-by-case error estimates for retrieved geophysical parameters and for channel-by-channel clear column radiances. Thresholds of these error estimates are used in a new approach for Quality Control. Finally, Version 5 also contains for the first time an approach to provide AIRS soundings in partially cloudy conditions that does not require use of any microwave data. This new AIRS Only sounding methodology, referred to as AIRS Version 5 AO, was developed as a backup to AIRS Version 5 should the AMSU-A instrument fail. Results are shown comparing the relative performance of the AIRS Version 4, Version 5, and Version 5 AO for the single day, January 25, 2003. The Goddard DISC is now generating and distributing products derived using the AIRS Science Team Version 5 retrieval algorithm. This paper also described the Quality Control flags contained in the DISC AIRS/AMSU retrieval products and their intended use for scientific research purposes.

A micro dew point sensor with a thermal detection principle

NASA Astrophysics Data System (ADS)

Kunze, M.; Merz, J.; Hummel, W.-J.; Glosch, H.; Messner, S.; Zengerle, R.

2012-01-01

We present a dew point temperature sensor with the thermal detection of condensed water on a thin membrane, fabricated by silicon micromachining. The membrane (600 × 600 × ~1 µm3) is part of a silicon chip and contains a heating element as well as a thermopile for temperature measurement. By dynamically heating the membrane and simultaneously analyzing the transient increase of its temperature it is detected whether condensed water is on the membrane or not. To cool the membrane down, a peltier cooler is used and electronically controlled in a way that the temperature of the membrane is constantly held at a value where condensation of water begins. This temperature is measured and output as dew point temperature. The sensor system works in a wide range of dew point temperatures between 1 K and down to 44 K below air temperature. In experimental investigations it could be proven that the deviation of the measured dew point temperatures compared to reference values is below ±0.2 K in an air temperature range of 22 to 70 °C. At low dew point temperatures of -20 °C (air temperature = 22 °C) the deviation increases to nearly -1 K.

Importance of temperature control for HEFLEX, a biological experiment for Spacelab 1. [plant gravitational physiology study

NASA Technical Reports Server (NTRS)

Chapman, D. K.; Brown, A. H.

1979-01-01

The importance of temperature control to HEFLEX, a Spacelab experiment designed to measure kinetic properties of Helianthis nutation in a low-g environment, is discussed. It is argued that the development of the HEFLEX experiment has been severely hampered by the inadequate control of ambient air temperature provided by the spacecraft module design. A worst case calculation shows that delivery of only 69% of the maximum yield of useful data from the HEFLEX system is guaranteed; significant data losses from inadequate temperature control are expected. The magnitude of the expected data losses indicates that the cost reductions associated with imprecise temperature controls may prove to be a false economy in the long term.

Estimation of cauliflower mass transfer parameters during convective drying

NASA Astrophysics Data System (ADS)

Sahin, Medine; Doymaz, İbrahim

2017-02-01

The study was conducted to evaluate the effect of pre-treatments such as citric acid and hot water blanching and air temperature on drying and rehydration characteristics of cauliflower slices. Experiments were carried out at four different drying air temperatures of 50, 60, 70 and 80 °C with the air velocity of 2.0 m/s. It was observed that drying and rehydration characteristics of cauliflower slices were greatly influenced by air temperature and pre-treatment. Six commonly used mathematical models were evaluated to predict the drying kinetics of cauliflower slices. The Midilli et al. model described the drying behaviour of cauliflower slices at all temperatures better than other models. The values of effective moisture diffusivities ( D eff ) were determined using Fick's law of diffusion and were between 4.09 × 10-9 and 1.88 × 10-8 m2/s. Activation energy was estimated by an Arrhenius type equation and was 23.40, 29.09 and 26.39 kJ/mol for citric acid, blanch and control samples, respectively.

Improving Comfort in Hot-Humid Climates with a Whole-House Dehumidifier, Windermere, Florida (Fact Sheet)

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

Not Available

2013-11-01

Maintaining comfort in a home can be challenging in hot-humid climates. At the common summer temperature set point of 75 degrees F, the perceived air temperature can vary by 11 degrees F because higher indoor humidity reduces comfort. Often the air conditioner (AC) thermostat set point is lower than the desirable cooling level to try to increase moisture removal so that the interior air is not humid or "muggy." However, this method is not always effective in maintaining indoor relative humidity (RH) or comfort. In order to quantify the performance of a combined whole-house dehumidifier (WHD) AC system, researchers frommore » the U.S. Department of Energy's Building America team Consortium of Advanced Residential Buildings (CARB) monitored the operation of two Lennox AC systems coupled with a Honeywell DH150 TrueDRY whole-house dehumidifier for a six-month period. By using a WHD to control moisture levels (latent cooling) and optimizing a central AC to control temperature (sensible cooling), improvements in comfort can be achieved while reducing utility costs. Indoor comfort for this study was defined as maintaining indoor conditions at below 60% RH and a humidity ratio of 0.012 lbm/lbm while at common dry bulb set point temperatures of 74 degrees -80 degrees F. In addition to enhanced comfort, controlling moisture to these levels can reduce the risk of other potential issues such as mold growth, pests, and building component degradation. Because a standard AC must also reduce dry bulb air temperature in order to remove moisture, a WHD is typically needed to support these latent loads when sensible heat removal is not desired.« less

Solid oxide fuel cell operable over wide temperature range

DOEpatents

Baozhen, Li; Ruka, Roswell J.; Singhal, Subhash C.

2001-01-01

Solid oxide fuel cells having improved low-temperature operation are disclosed. In one embodiment, an interfacial layer of terbia-stabilized zirconia is located between the air electrode and electrolyte of the solid oxide fuel cell. The interfacial layer provides a barrier which controls interaction between the air electrode and electrolyte. The interfacial layer also reduces polarization loss through the reduction of the air electrode/electrolyte interfacial electrical resistance. In another embodiment, the solid oxide fuel cell comprises a scandia-stabilized zirconia electrolyte having high electrical conductivity. The scandia-stabilized zirconia electrolyte may be provided as a very thin layer in order to reduce resistance. The scandia-stabilized electrolyte is preferably used in combination with the terbia-stabilized interfacial layer. The solid oxide fuel cells are operable over wider temperature ranges and wider temperature gradients in comparison with conventional fuel cells.

Multi-load Groups Coordinated Load Control Strategy Considering Power Network Constraints

NASA Astrophysics Data System (ADS)

Liu, Meng; Zhao, Binchao; Wang, Jun; Zhang, Guohui; Wang, Xin

2017-05-01

Loads with energy storage property can actively participate in power balance for power systems, this paper takes air conditioner as a controllable load example, proposing a multi-load groups coordinated load control strategy considering power network constraints. Firstly, two load control modes considering recovery of load diversity are designed, blocking power oscillation of aggregated air conditioners. As the same time, air conditioner temperature setpoint recovery control strategy is presented to avoid power recovery peak. Considering inherent characteristics of two load control modes, an coordinated load control mode is designed by combining the both. Basing on this, a multi-load groups coordinated load control strategy is proposed. During the implementing of load control, power network constraints should be satisfied. An indice which can reflect the security of power system operating is defined. By minimizing its value through optimization, the change of air conditioning loads’ aggregated power on each load bus can be calculated. Simulations are conducted on an air conditioners group and New England 10-generator 39-bus system, verifying the effectiveness of the proposed multi-load groups coordinated load control strategy considering power network constraints.

Integrated energy balance analysis for Space Station Freedom

NASA Technical Reports Server (NTRS)

Tandler, John

1991-01-01

An integrated simulation model is described which characterizes the dynamic interaction of the energy transport subsystems of Space Station Freedom for given orbital conditions and for a given set of power and thermal loads. Subsystems included in the model are the Electric Power System (EPS), the Internal Thermal Control System (ITCS), the External Thermal Control System (ETCS), and the cabin Temperature and Humidity Control System (THC) (which includes the avionics air cooling, cabin air cooling, and intermodule ventilation systems). Models of the subsystems were developed in a number of system-specific modeling tools and validated. The subsystem models are then combined into integrated models to address a number of integrated performance issues involving the ability of the integrated energy transport system of Space Station Freedom to provide power, controlled cabin temperature and humidity, and equipment thermal control to support operations.

Controlled Atmosphere High Temperature SPM for electrochemical measurements

NASA Astrophysics Data System (ADS)

Vels Hansen, K.; Sander, C.; Koch, S.; Mogensen, M.

2007-03-01

A new controlled atmosphere high temperature SPM has been designed and build for the purpose of performing electrochemical measurements on solid oxide fuel cell materials. The first tests show that images can be obtained at a surface temperature of 465°C in air with a standard AFM AC probe. The aim is to produce images at a surface temperature of 800°C with electrically conducting ceramic probes as working electrodes that can be positioned at desired locations at the surface for electrochemical measurements.

2003 NASA Seal/Secondary Air System Workshop. Volume 1

NASA Technical Reports Server (NTRS)

Steinetz, Bruce M. (Editor); Hendricks, Robert C. (Editor)

2004-01-01

The following reports were included in the 2003 NASA Seal/Secondary Air System Workshop:Low Emissions Alternative Power (LEAP); Overview of NASA Glenn Seal Developments; NASA Ultra Efficient Engine Technology Project Overview; Development of Higher Temperature Abradable Seals for Industrial Gas Turbines; High Misalignment Carbon Seals for the Fan Drive Gear System Technologies; Compliant Foil Seal Investigations; Test Rig for Evaluating Active Turbine Blade Tip Clearance Control Concepts; Controls Considerations for Turbine Active Clearance Control; Non-Contacting Finger Seal Developments and Design Considerations; Effect of Flow-Induced Radial Load on Brush Seal/Rotor Contact Mechanics; Seal Developments at Flowserve Corporation; Investigations of High Pressure Acoustic Waves in Resonators With Seal-Like Features; Numerical Investigations of High Pressure Acoustic Waves in Resonators; Feltmetal Seal Material Through-Flow; "Bimodal" Nuclear Thermal Rocket (BNTR) Propulsion for Future Human Mars Exploration Missions; High Temperature Propulsion System Structural Seals for Future Space Launch Vehicles; Advanced Control Surface Seal Development for Future Space Vehicles; High Temperature Metallic Seal Development for Aero Propulsion and Gas Turbine Applications; and BrazeFoil Honeycomb.

Non-climatic thermal adaptation: implications for species' responses to climate warming.

PubMed

Marshall, David J; McQuaid, Christopher D; Williams, Gray A

2010-10-23

There is considerable interest in understanding how ectothermic animals may physiologically and behaviourally buffer the effects of climate warming. Much less consideration is being given to how organisms might adapt to non-climatic heat sources in ways that could confound predictions for responses of species and communities to climate warming. Although adaptation to non-climatic heat sources (solar and geothermal) seems likely in some marine species, climate warming predictions for marine ectotherms are largely based on adaptation to climatically relevant heat sources (air or surface sea water temperature). Here, we show that non-climatic solar heating underlies thermal resistance adaptation in a rocky-eulittoral-fringe snail. Comparisons of the maximum temperatures of the air, the snail's body and the rock substratum with solar irradiance and physiological performance show that the highest body temperature is primarily controlled by solar heating and re-radiation, and that the snail's upper lethal temperature exceeds the highest climatically relevant regional air temperature by approximately 22°C. Non-climatic thermal adaptation probably features widely among marine and terrestrial ectotherms and because it could enable species to tolerate climatic rises in air temperature, it deserves more consideration in general and for inclusion into climate warming models.

Calculation of air movement in ice caves by using the CalcFlow method

NASA Astrophysics Data System (ADS)

Meyer, Christiane; Pflitsch, Andreas; Maggi, Valter

2017-04-01

We present a method to determine the air flow regime within ice caves by temperature loggers. Technical capabilities of conducting airflow measurements are restricted by the availability of energy at the ice cave study sites throughout the year. Though the knowledge of the airflow regime is a prerequisite for the understanding of the cave climate. By cross-correlating different time series of air temperature measurements inside a cave, we define the travel time of the air between the loggers, which corresponds to the time shift of best correlation, and use this result to derive the airflow speed. Then we estimate the temperature biases and scale factors for the temperature variations observed by the different loggers by a least squares adjustment. As quality control for bias and scale we use the formal errors of the estimation process. For the calculated airflow speed quality criteria are developed by use of a simulation study. Furthermore we will apply the method to temperature measurements in the static ice cave Schellenberger Eishöhle (Germany). In the end we show how the method can be used as an advanced filter for the separation of different signal contents of the temperature measurements.

Control means for a gas turbine engine

NASA Technical Reports Server (NTRS)

Beitler, R. S.; Sellers, F. J.; Bennett, G. W. (Inventor)

1982-01-01

A means is provided for developing a signal representative of the actual compressor casing temperature, a second signal representative of compressor inlet gas temperature, and a third signal representative of compressor speed. Another means is provided for receiving the gas temperature and compressor speed signals and developing a schedule output signal which is a representative of a reference casing temperature at which a predetermined compressor blade stabilized clearance is provided. A means is also provided for comparing the actual compressor casing temperature signal and the reference casing temperature signal and developing a clearance control system representative of the difference. The clearance control signal is coupled to a control valve which controls a flow of air to the compressor casing to control the clearance between the compressor blades and the compressor casing. The clearance control signal can be modified to accommodate transient characteristics. Other embodiments are disclosed.

Spatial Characteristics of Small Green Spaces' Mitigating Effects on Microscopic Urban Heat Islands

NASA Astrophysics Data System (ADS)

Park, J.; Lee, D. K.; Jeong, W.; Kim, J. H.; Huh, K. Y.

2015-12-01

The purpose of the study is to find small greens' disposition, types and sizes to reduce air temperature effectively in urban blocks. The research sites were six high developed blocks in Seoul, Korea. Air temperature was measured with mobile loggers in clear daytime during summer, from August to September, at screen level. Also the measurement repeated over three times a day during three days by walking and circulating around the experimental blocks and the control blocks at the same time. By analyzing spatial characteristics, the averaged air temperatures were classified with three spaces, sunny spaces, building-shaded spaces and small green spaces by using Kruskal-Wallis Test; and small green spaces in 6 blocks were classified into their outward forms, polygonal or linear and single or mixed. The polygonal and mixed types of small green spaces mitigated averaged air temperature of each block which they belonged with a simple linear regression model with adjusted R2 = 0.90**. As the area and volume of these types increased, the effect of air temperature reduction (ΔT; Air temperature difference between sunny space and green space in a block) also increased in a linear relationship. The experimental range of this research is 100m2 ~ 2,000m2 of area, and 1,000m3 ~ 10,000m3 of volume of small green space. As a result, more than 300m2 and 2,300m3 of polygonal green spaces with mixed vegetation is required to lower 1°C; 650m2 and 5,000m3 of them to lower 2°C; about 2,000m2 and about 10,000m3 of them to lower 4°C air temperature reduction in an urban block.

Bias Correction for Assimilation of Retrieved AIRS Profiles of Temperature and Humidity

NASA Technical Reports Server (NTRS)

Blakenship, Clay; Zavodsky, Bradley; Blackwell, William

2014-01-01

The Atmospheric Infrared Sounder (AIRS) is a hyperspectral radiometer aboard NASA's Aqua satellite designed to measure atmospheric profiles of temperature and humidity. AIRS retrievals are assimilated into the Weather Research and Forecasting (WRF) model over the North Pacific for some cases involving "atmospheric rivers". These events bring a large flux of water vapor to the west coast of North America and often lead to extreme precipitation in the coastal mountain ranges. An advantage of assimilating retrievals rather than radiances is that information in partly cloudy fields of view can be used. Two different Level 2 AIRS retrieval products are compared: the Version 6 AIRS Science Team standard retrievals and a neural net retrieval from MIT. Before assimilation, a bias correction is applied to adjust each layer of retrieved temperature and humidity so the layer mean values agree with a short-term model climatology. WRF runs assimilating each of the products are compared against each other and against a control run with no assimilation. Forecasts are against ERA reanalyses.

Career Directions: HVACR Technician

ERIC Educational Resources Information Center

Moore, Pam

2005-01-01

Heating/ventilation/air conditioning/refrigeration (HVACR) technicians (also known as "heating and cooling technicians") are the people who install, maintain, test and repair the machines that control temperature, circulation, moisture and purity of air in residential, commercial and industrial buildings. These systems consist of a variety of…

Year-round Application of Water Curtain for Environmental Control in Greenhouse

NASA Astrophysics Data System (ADS)

Ibuki, R.; Sugita, E.

2011-12-01

In large area of Japan needs forced environmental control to cultivate yields in hard temperature condition. Water Curtain is applied in Japan for night time air temperature control of small greenhouse, making strawberry and covered by plastic film. Water is splayed on extended plastic film, located above strawberry and below roof film. Underground water is utilized for cooling in summer, and warming in winter. Heat exchange between water and ground, and also water and air in the greenhouse is occurring in this system. Furthermore, heat transfer by radiation effect is also controlled by water membrane. In winter night, infrared radiation through plastic film is reduced by water membrane because of its high absorption coefficient on wave length of infrared. Besides water has a high transparency on wave length of visible light. These features are useful on the daytime radiation control of greenhouse to maintain visible light level for photosynthesis and to reduce excess infrared, damages yields in summer. Also in daytime of sunny day in winter season, temperature is too high to cultivate yields in closed greenhouse. Under this situation, water curtain is useful to storage from broad area in greenhouse excess heat from air in the circulation water. Warm water is useful to maintain temperature in greenhouse. On the contrary, in summer season, water can storage heat in daytime and release in night time. Water curtain system will contribute to be a sustainable and low energy consumption system to maintain comfortable environment for yields growth. For this reason we are considering to use water curtain in year-round. At the first step of the year-round application, day time use in summer is experimentally investigated. General water curtain splays water on plastic film extended on metal pipe. In this situation water is gathered at valley part of the film. Then water membrane is partially made and radiation control is not effective at large area. Therefore we applied new covering way to realize higher water covering ratio. With this way selective reduction effect of water curtain, which reduce infrared more than visible light is quantitatively measured. Also small greenhouse to growth plants under it is settled to measure thermal net, heat absorption, water and air temperature variation and yields growth. From measurements way of making water membrane influenced water temperature elevation.

Afterburner performance of film-vaporizing V-gutters for inlet temperatures up to 1255 K

NASA Technical Reports Server (NTRS)

Branstetter, J. R.; Reck, G. M.

1973-01-01

Combustion tests of five variations of an integral, spray-bar - flameholder combination were conducted in a 0.49-m-diameter duct. Emphasis was on low levels of augmentation. Fuel impinged on guide plates, mixed with a controlled amount of inlet air, vaporized, and was guided into the V-gutter wake. Combustor length was 0.92 m. Good performance was demonstrated at fuel-air ratios less than 0.025 for inlet temperatures of 920 to 1255 K. Maximum combustion efficiency occured in the vicinity of fuel-air ratios of 0.02 and was 92 to 100 percent, depending on the inlet temperature. Lean blowout fuel-air ratios were in the vicinity of 0.005. Improvements in rich-limit blowout resulted from enlarging the guide-flow passageway areas. Other means of extending the operating range are suggested. A simplified afterburner concept for application to advanced engines is described.

The effects of cooling systems on CO2-lased human enamel.

PubMed

Lian, H J; Lan, W H; Lin, C P

1996-12-01

The thermal effects on dentin during CO2 laser irradiation on human enamel were investigated. To simulate the clinical practice, two cooling methods (air and water spray) were applied immediately after laser exposure, whereas one group without cooling was served as control. Three hundred and sixty uniform tooth blocks were obtained from freshly extracted human third molars. Temperature change measurements were made via electrical thermocouple implanted within the tooth block 2 mm away from the enamel surface. Experimental treatments consisted of lasing without cooling, lasing with 0.5-ml/sec water cooling, and lasing with 15-psi air cooling. Our results indicated that (1) both air- and water-cooling groups could reduce temperature elevation significantly; (2) the larger power energy resulted in the higher temperature elevation. In conclusion, for CO2 laser irradiation on human enamel both water- and air-cooling methods may be effective on prevention of thermal damage of pulp.

Analysis of air quality in Dire Dawa, Ethiopia.

PubMed

Kasim, Oluwasinaayomi Faith; Woldetisadik Abshare, Muluneh; Agbola, Samuel Babatunde

2017-12-07

Ambient air quality was monitored and analyzed to develop air quality index and its implications for livability and climate change in Dire Dawa, Ethiopia. Using survey research design, 16 georeferenced locations, representing different land uses, were randomly selected and assessed for sulfur dioxide (SO 2 ), nitrogen dioxide (NO 2 ), carbon dioxide (CO 2 ), carbon monoxide (CO),volatile organic compounds (VOCs), and meteorological parameters (temperature and relative humidity). The study found mean concentrations across all land uses for SO 2 of 0.37 ± 0.08 ppm, NO 2 of 0.13 ± 0.17 ppm, CO 2 of 465.65 ± 28.63 ppm, CO of 3.35 ± 2.04 ppm, and VOCs of 1850.67 ± 402 ppm. An air quality index indicated that ambient air quality for SO 2 was very poor, NO 2 ranged from moderate to very poor, whereas CO rating was moderate. Significant positive correlations existed between temperature and NO 2 , CO 2 , and CO and between humidity and VOCs. Significant relationships were also recorded between CO 2 and NO 2 and between CO and CO 2 . Poor urban planning, inadequate pollution control measure, and weak capacity to monitor air quality have implications for energy usage, air quality, and local meteorological parameters, with subsequent feedback into global climate change. Implementation of programs to monitor and control emissions in order to reduce air pollution will provide health, economic, and environmental benefits to the city. The need to develop and implement emission control programs to reduce air pollution in Dire Dawa City is urgent. This will provide enormous economic, health, and environmental benefits. It is expected that economic effects of air quality improvement will offset the expenditures for pollution control. Also, strategies that focus on air quality and climate change present a unique opportunity to engage different stakeholders in providing inclusive and sustainable development agenda for Dire Dawa.

Regulating low-NOx and high-burnout deep-air-staging combustion under real-furnace conditions in a 600 MWe down-fired supercritical boiler by strengthening the staged-air effect.

PubMed

Kuang, Min; Wang, Zhihua; Zhu, Yanqun; Ling, Zhongqian; Li, Zhengqi

2014-10-21

A 600 MW(e) down-fired pulverized-coal supercritical boiler, which was equipped with a deep-air-staging combustion system for reducing the particularly high NOx emissions, suffered from the well-accepted contradiction between low NOx emissions and high carbon in fly ash, in addition to excessively high gas temperatures in the hopper that jeopardized the boiler's safe operations. Previous results uncovered that under low-NOx conditions, strengthening the staged-air effect by decreasing the staged-air angle and simultaneously increasing the staged-air damper opening alleviated the aforementioned problems to some extent. To establish low-NOx and high-burnout circumstances and control the aforementioned hopper temperatures, a further staged-air retrofit with horizontally redirecting staged air through an enlarged staged-air slot area was performed to greatly strengthen the staged-air effect. Full-load industrial-size measurements were performed to confirm the availability of this retrofit. The present data were compared with those published results before the retrofit. High NOx emissions, low carbon in fly ah, and high hopper temperatures (i.e., levels of 1036 mg/m(3) at 6% O2, 3.72%, and about 1300 °C, respectively) appeared under the original conditions with the staged-air angle of 45° and without overfire air (OFA) application. Applying OFA and reducing the angle to 20° achieved an apparent NOx reduction and a moderate hopper temperature decrease while a sharp increase in carbon in fly ash (i.e., levels of 878 mg/m(3) at 6% O2, about 1200 °C, and 9.81%, respectively). Fortunately, the present staged-air retrofit was confirmed to be applicable in regulating low-NOx, high-burnout, and low hopper temperature circumstances (i.e., levels of 867 mg/m(3) at 6% O2, 5.40%, and about 1100 °C, respectively).

High Technology Centrifugal Compressor for Commercial Air Conditioning Systems

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

Ruckes, John

2006-04-15

R&D Dynamics, Bloomfield, CT in partnership with the State of Connecticut has been developing a high technology, oil-free, energy-efficient centrifugal compressor called CENVA for commercial air conditioning systems under a program funded by the US Department of Energy. The CENVA compressor applies the foil bearing technology used in all modern aircraft, civil and military, air conditioning systems. The CENVA compressor will enhance the efficiency of water and air cooled chillers, packaged roof top units, and other air conditioning systems by providing an 18% reduction in energy consumption in the unit capacity range of 25 to 350 tons of refrigeration Themore » technical approach for CENVA involved the design and development of a high-speed, oil-free foil gas bearing-supported two-stage centrifugal compressor, CENVA encompassed the following high technologies, which are not currently utilized in commercial air conditioning systems: Foil gas bearings operating in HFC-134a; Efficient centrifugal impellers and diffusers; High speed motors and drives; and System integration of above technologies. Extensive design, development and testing efforts were carried out. Significant accomplishments achieved under this program are: (1) A total of 26 builds and over 200 tests were successfully completed with successively improved designs; (2) Use of foil gas bearings in refrigerant R134a was successfully proven; (3) A high speed, high power permanent magnet motor was developed; (4) An encoder was used for signal feedback between motor and controller. Due to temperature limitations of the encoder, the compressor could not operate at higher speed and in turn at higher pressure. In order to alleviate this problem a unique sensorless controller was developed; (5) This controller has successfully been tested as stand alone; however, it has not yet been integrated and tested as a system; (6) The compressor successfully operated at water cooled condensing temperatures Due to temperature limitations of the encoder, it could not be operated at air cooled condensing temperatures. (7) The two-stage impellers/diffusers worked well separately but combined did not match well.« less

Sidewalk Landscape Structure and Thermal Conditions for Child and Adult Pedestrians

PubMed Central

Kim, Young-Jae; Lee, Chanam; Kim, Jun-Hyun

2018-01-01

Walking is being promoted for health and transportation purposes across all climatic regions in the US and beyond. Despite this, an uncomfortable microclimate condition along sidewalks is one of the major deterrents of walking, and more empirical research is needed to determine the risks of heat exposure to pedestrians while walking. This study examined the effect of street trees and grass along sidewalks on air temperatures. A series of thermal images were taken at the average heights of adults and children in the US to objectively measure the air temperatures of 10 sidewalk segments in College Station, TX, USA. After controlling the other key physical environmental conditions, sidewalks with more trees or wider grass buffer areas had lower air temperatures than those with less vegetation. Children were exposed to higher temperatures due to the greater exposure or proximity to the pavement surface, which tends to have higher radiant heat. Multivariate regression analysis suggested that the configuration of trees and grass buffers along the sidewalks helped to promote pleasant thermal conditions and reduced the differences in ambient air temperatures measured at child and adult heights. This study suggests that street trees and vegetated ground help reduce the air temperatures, leading to more thermally comfortable environments for both child and adult pedestrians in warm climates. The thermal implications of street landscape require further attention by researchers and policy makers that are interested in promoting outdoor walking. PMID:29346312

Does air-breathing meet metabolic demands of the juvenile snakehead, Channa argus, in multiple conditions

PubMed Central

Li, Yongli; Lv, Xiao; Zhou, Jing; Shi, Chenchen; Duan, Ting

2017-01-01

ABSTRACT The objective of this study was to examine how the respiratory metabolism of the snakehead Channa argus changed when it shifted from breathing water to breathing air, and how increased metabolic demands caused by temperature, feeding, and exhaustive exercise affect its survival in air. The results demonstrated that the oxygen consumption rate (MO2) of the snakehead was lower for aerial respiration than aquatic respiration by 12.1, 24.5 and 20.4% at 20, 25, and 30°C, respectively. Survival time was significantly shortened with increasing temperature and was negatively correlated with the resting MO2 in air (MO2Air). No obvious feeding metabolic response was observed in the snakeheads fed at 1% and 3% body mass levels while breathing air. The maximum MO2Air of the snakehead after exhaustive exercise was significantly higher than the resting MO2Air of the control group. The results suggest that the snakehead could survive out of water by breathing air for varying lengths of time, depending on ambient temperature and metabolic demand. Additionally, some degree of metabolic depression occurs in the snakehead when breathing air. The metabolic demand associated with exercise in the snakehead, but not that associated with feeding, can be supported by its capacity for breathing air to some extent. PMID:28396489

Association Between Air Temperature and Cancer Death Rates in Florida: An Ecological Study.

PubMed

Hart, John

2015-01-01

Proponents of global warming predict adverse events due to a slight warming of the planet in the last 100 years. This ecological study tests one of the possible arguments that might support the global warming theory - that it may increase cancer death rates. Thus, average daily air temperature is compared to cancer death rates at the county level in a U.S. state, while controlling for variables of smoking, race, and land elevation. The study revealed that lower cancer death rates were associated with warmer temperatures. Further study is indicated to verify these findings.

Association Between Air Temperature and Cancer Death Rates in Florida

PubMed Central

2015-01-01

Proponents of global warming predict adverse events due to a slight warming of the planet in the last 100 years. This ecological study tests one of the possible arguments that might support the global warming theory – that it may increase cancer death rates. Thus, average daily air temperature is compared to cancer death rates at the county level in a U.S. state, while controlling for variables of smoking, race, and land elevation. The study revealed that lower cancer death rates were associated with warmer temperatures. Further study is indicated to verify these findings. PMID:26674418

The Shock and Vibration Bulletin. Part 3. Invited Papers, Pyrotechnic Shock, Pyrotechnic Shock Workshop

DTIC Science & Technology

1986-08-01

Technology Laboratory, Watertown, MA AIR FORCE BASIC RESEARCH IN DYNAMICS AND CONTROL OF LARGE SPACE STRUCTURES Anthony K. Amos, Boiling Air Force Base...Engineering, Watchun$, NJ TEMPERATURE SHIFT CONSIDERATIONS FOR DAMPING MATERIALS L. Rogers, Air Force Wright Aeronautictl Laboratories, Wright...INDUCED CAVITY ACOUSTICS L.L. Shaw,. Air Force Wr4ht Aeroaauical Laborawrics, Wri•ht-Paucswon AFB. OH i 4i SESSION CHAIRMEN AND COCHAIRMEN 56th Shock and

Mitigation of building-related polychlorinated biphenyls in indoor air of a school

PubMed Central

2012-01-01

Background Sealants and other building materials sold in the U.S. from 1958 - 1971 were commonly manufactured with polychlorinated biphenyls (PCBs) at percent quantities by weight. Volatilization of PCBs from construction materials has been reported to produce PCB levels in indoor air that exceed health protective guideline values. The discovery of PCBs in indoor air of schools can produce numerous complications including disruption of normal operations and potential risks to health. Understanding the dynamics of building-related PCBs in indoor air is needed to identify effective strategies for managing potential exposures and risks. This paper reports on the efficacy of selected engineering controls implemented to mitigate concentrations of PCBs in indoor air. Methods Three interventions (ventilation, contact encapsulation, and physical barriers) were evaluated in an elementary school with PCB-containing caulk and elevated PCB concentrations in indoor air. Fluorescent light ballasts did not contain PCBs. Following implementation of the final intervention, measurements obtained over 14 months were used to assess the efficacy of the mitigation methods over time as well as temporal variability of PCBs in indoor air. Results Controlling for air exchange rates and temperature, the interventions produced statistically significant (p < 0.05) reductions in concentrations of PCBs in indoor air of the school. The mitigation measures remained effective over the course of the entire follow-up period. After all interventions were implemented, PCB levels in indoor air were associated with indoor temperature. In a "broken-stick" regression model with a node at 20°C, temperature explained 79% of the variability of indoor PCB concentrations over time (p < 0.001). Conclusions Increasing outdoor air ventilation, encapsulating caulk, and constructing a physical barrier over the encapsulated material were shown to be effective at reducing exposure concentrations of PCBs in indoor air of a school and also preventing direct contact with PCB caulk. In-place management methods such as these avoid the disruption and higher costs of demolition, disposal and reconstruction required when PCB-containing building materials are removed from a school. Because of the influence of temperature on indoor air PCB levels, risk assessment results based on short-term measurements, e.g., a single day or season, may be erroneous and could lead to sub-optimal allocation of resources. PMID:22490055

Heat transfer enhancement of flow insulator by combined stainless steel fibrous and wire net porous materials

NASA Astrophysics Data System (ADS)

Khantikomol, P.; Polsongkram, M.; Apisitpinyo, W.; Poowadin, T.

2018-01-01

The present research article aims to propose the heat transfer enhancement of the flow insulator using combined fibrous and wire net stainless steel porous material. The stainless fibrous plate with porosity of 0.9292 was combined to the stainless steel wire net having pore per inch (PPI) of 16 and total thickness of 30 mm. Two models of the arranging porous plates were prepared, which were model BA and model AB. Each porous plate segment had the same thickness. The examined porous plate model have porosities of 0.8452. The porous plate was placed normal to the flow direction. The air was used as working fluid heated by 5 kW electric heater, which was controlled by the automatic temperature control. Type-K thermocouples were employed to measure the air temperatures. The temperature at front of the porous plate was varied to be 350, 450, and 550°C. The air flow rate was varied in the range of 4-12 m3/hr. The experimental result showed that the temperature drop across the porous plate and the thermal efficiency increase with the inlet temperature. The air velocity slightly affects the temperature profile inside the test section at the upstream side of the porous plate but greatly affects temperature inside the porous plate. In consideration of the arranging porous plate, placing of the stainless steel wire net at the upstream side and placing the stainless steel fibrous at downstream side (model BA) results in the highest temperature drop and the highest thermal efficiency. At Re 733 and inlet temperature 550°C for model BA at 30 mm thickness, the thermal efficiency was 50%. It was shown that the combined stainless steel fibrous and stainless steel wire net porous material could be a good flow insulator.

Investigation of air gasification of micronized coal, mechanically activated using the plasma control of the process

NASA Astrophysics Data System (ADS)

Butakov, Evgenii; Burdukov, Anatoly; Chernetskiy, Mikhail; Kuznetsov, Victor

2017-10-01

Combination of the processes of coal combustion and gasification into a single technology of mechano-chemical and plasma-chemical activation is of a considerable scientific and technological interest. Enhancement of coal reactivity at their grinding with mechanical activation is associated with an increase in the reaction rate of carbon material, and at plasma-chemical effect, the main is an increase in reactivity of the oxidizing agent caused by the high plasma temperatures of atomic oxygen. The process of gasification was studied on the 1-MW setup with tangential scroll supply of pulverized coal-air mixture and cylindrical reaction chamber. Coal ground by the standard boiler mill is fed to the disintegrator, then, it is sent to the scroll inlet of the burner-reactor with the transport air. Pulverized coal is ignited by the plasmatron of 10-kW power. In experiments on air gasification of micronized coal, carried out at the temperature in the reaction chamber of 1000-1200°C and air excess α = 0.3-1, the data on CO concentration of 11% and H2 concentration of up to 6% were obtained. Air and air-steam gasification of mechanically-activated micronized coals with plasma control was calculated using SigmaFlow software package.

Porosity control in nanoporous carbide-derived carbon by oxidation in air and carbon dioxide

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

Osswald, S.; Portet, C.; Gogotsi, Y., E-mail: gogotsi@drexel.ed

2009-07-15

Carbide-derived carbons (CDC) allow a precise control over the pore size through the selection of the carbide precursor and varying of the synthesis conditions. However, their pore volume is limited by the carbide stoichiometry. While activation of carbons derived from various organic precursors has been widely studied, this process may similarly be able to increase the pore volume and specific surface area of CDC. Oxidation of carbide-derived carbon in air and CO{sub 2} at different temperatures and times allows for significant increase in pore volume and specific surface area as well as control over average pore size with subnanometer accuracy.more » The effect of activation and associated changes in the pore volume and surface area on the hydrogen uptake are also discussed. - Graphical abstract: Carbide-derived carbons (CDC) provide great potential for sorption of toxicants and gas storage applications. Activation of CDC in air and CO{sub 2} at different temperatures and times is applied in order to maximize pore volume and specific surface area, and control the average pore size with subnanometer accuracy.« less

The remote infrared remote control system based on LPC1114

NASA Astrophysics Data System (ADS)

Ren, Yingjie; Guo, Kai; Xu, Xinni; Sun, Dayu; Wang, Li

2018-05-01

In view of the shortcomings such as the short control distance of the traditional air conditioner remote controller on the market nowadays and combining with the current smart home new mode "Cloud+ Terminal" mode, a smart home system based on internet is designed and designed to be fully applied to the simple and reliable features of the LPC1114 chip. The controller is added with temperature control module, timing module and other modules. Through the actual test, it achieved remote control air conditioning, with reliability and stability and brought great convenience to people's lives.

Induced hypothermia for infants with hypoxic- ischemic encephalopathy using a servo-controlled fan: an exploratory pilot study.

PubMed

Horn, Alan; Thompson, Clare; Woods, David; Nel, Alida; Bekker, Adrie; Rhoda, Natasha; Pieper, Clarissa

2009-06-01

Several trials suggest that hypothermia is beneficial in selected infants with hypoxic-ischemic encephalopathy. However, the cooling methods used required repeated interventions and were either expensive or reported significant temperature variation. The objective of this pilot study was to describe the use, efficacy, and physiologic impact of an inexpensive servo-controlled cooling fan blowing room-temperature air. A servo-controlled fan was manufactured and used to cool 10 infants with hypoxic-ischemic encephalopathy to a rectal temperature of 33 degrees C to 34 degrees C. The infants were sedated with phenobarbital, but clonidine was administered to some infants if shivering or discomfort occurred. A servo-controlled radiant warmer was used simultaneously with the fan to prevent overcooling. The settings used on the fan and radiant warmer differed slightly between some infants as the technique evolved. A rectal temperature of 34 degrees C was achieved in a median time of 58 minutes. Overcooling did not occur, and the mean temperature during cooling was 33.6 degrees C +/- 0.2 degrees C. Inspired oxygen requirements increased in 6 infants, and 5 infants required inotropic support during cooling, but this was progressively reduced after 1 to 2 days. Dehydration did not occur. Five infants shivered when faster fan speeds were used, but 4 of the 5 infants had hypomagnesemia. Shivering was controlled with clonidine in 4 infants, but 1 infant required morphine. Servo-controlled fan cooling with room-temperature air, combined with servo-controlled radiant warming, was an effective, simple, and safe method of inducing and maintaining rectal temperatures of 33 degrees C to 34 degrees C in sedated infants with hypoxic-ischemic encephalopathy. After induction of hypothermia, a low fan speed facilitated accurate temperature control, and warmer-controlled rewarming at 0.2 degrees C increments every 30 minutes resulted in more appropriate rewarming than when 0.5 degrees C increments every hour were used.

Winter to Spring Transition in Europe 48-45 degrees N: From Temperature Control by Advection to Control by Insolation

NASA Technical Reports Server (NTRS)

Otterman, J.; Ardizzone, J.; Atlas, R.; Hu, H.; Jusem, J. C.; Starr, D.

1999-01-01

As established in previous studies, and analyzed further herein for the years 1988-1998, warm advection from the North Atlantic is the predominant control of the surface-air temperature in northern-latitude Europe in late winter. This thesis is supported by the substantial correlation Cti between the speed of the southwesterly surface winds over the eastern North Atlantic, as quantified by a specific Index Ina, and the 2-meter level temperature Ts over central Europe (48-54 deg N; 5-25 deg E), for January, February and early March. In mid-March and subsequently, the correlation Cti drops drastically (quite often it is negative). The change in the relationship between Ts and Ina marks a transition in the control of the surface-air temperature. As (a) the sun rises higher in the sky, (b) the snows melt (the surface absorptivity can increase by a factor of 3.0), (c) the ocean-surface winds weaken, and (d) the temperature difference between land and ocean (which we analyze) becomes small, absorption of insolation replaces the warm advection as the dominant control of the continental temperature. We define the onset of spring by this transition, which evaluated for the period of our study occurs at pentad 16 (Julian Date 76, that is, March 16). The control by insolation means that the surface is cooler under cloudy conditions than under clear skies. This control produces a much smaller interannual variability of the surface temperature and of the lapse rate than prevailing in winter, when the control is by advection. Regional climatic data would be of greatest value for agriculture and forestry if compiled for well-defined seasons. For continental northern latitudes, analysis presented here of factors controlling the surface temperature appears an appropriate tool for this task.

Spatial Correlations of Anomaly Time Series of AIRS Version-6 Land Surface Skin Temperatures with the Nino-4 Index

NASA Technical Reports Server (NTRS)

Susskind, Joel; Lee, Jae N.; Iredell, Lena

2013-01-01

The AIRS Science Team Version-6 data set is a valuable resource for meteorological studies. Quality Controlled earth's surface skin temperatures are produced on a 45 km x 45 km spatial scale under most cloud cover conditions. The same retrieval algorithm is used for all surface types under all conditions. This study used eleven years of AIRS monthly mean surface skin temperature and cloud cover products to show that land surface skin temperatures have decreased significantly in some areas and increased significantly in other areas over the period September 2002 through August 2013. These changes occurred primarily at 1:30 PM but not at 1:30 AM. Cooling land areas contained corresponding increases in cloud cover over this time period, with the reverse being true for warming land areas. The cloud cover anomaly patterns for a given month are affected significantly by El Nino/La Nina activity, and anomalies in cloud cover are a driving force behind anomalies in land surface skin temperature.

Temperature Controller System for Gas Gun Targets

NASA Astrophysics Data System (ADS)

Bucholtz, S. M.; Gehr, R. J.; Rupp, T. D.; Sheffield, S. A.; Robbins, D. L.

2006-07-01

A temperature controller system capable of heating and cooling gas gun targets over the range -75°C to +120°C was designed and tested. The system uses cold nitrogen gas from a liquid nitrogen Dewar for cooling and compressed air for heating. Two gas flow heaters control the gas temperature for both heating and cooling. One heater controls the temperature of the target mounting plate and the other the temperature of a copper tubing coil surrounding the target. Each heater is separately adjustable, so the target material will achieve a uniform temperature throughout its volume. A magnetic gauge membrane with integrated thermocouples was developed to measure the internal temperature of the target. Using this system, multiple magnetic gauge shock experiments, including equation-of-state measurements and shock initiation of high explosives, can be performed over a range of initial temperatures. Successful heating and cooling tests were completed on Teflon samples.

Dedication of emergency diesel generators` control air subsystem

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

Harrington, M.; Myers, G.; Palumbo, M.

1994-12-31

In the spring of 1993, the need to upgrade Seabrook Station`s emergency diesel generators` (EDGs`) control air system from nonsafety related to safety related was identified. This need was identified as a result of questions raised by the US Nuclear Regulatory Commission, which was conducting an Electrical Distribution Safety Functional Inspection at Seabrook at that time. The specific reason for the reassignment of safety classification was recognition that failure of the control air supply to the EDGs` jacket cooling water temperature control valves could cause overcooling of the EDGs, which potentially could result in EDG failure during long-term operation. Thismore » paper addresses how the installed control air system was upgraded to safety related using Seabrook`s Commercial Grade Dedication (CGD) Program and how, by using the dedication skills obtained over the past few years, it was done at minimal cost.« less

40 CFR 86.605-88 - Maintenance of records; submittal of information.

Code of Federal Regulations, 2011 CFR

2011-07-01

..., pressure increase across the pump, and the temperature set point of the temperature control system. (2... samples are being collected. (3) Humidity of dilution air. (4) Manufacturer, model, type and serial number..., ambient temperature and humidity. (2) Data and time of day. (ii) In lieu of recording test equipment...

40 CFR 86.605-88 - Maintenance of records; submittal of information.

Code of Federal Regulations, 2012 CFR

2012-07-01

..., pressure increase across the pump, and the temperature set point of the temperature control system. (2... samples are being collected. (3) Humidity of dilution air. (4) Manufacturer, model, type and serial number..., ambient temperature and humidity. (2) Data and time of day. (ii) In lieu of recording test equipment...

40 CFR 86.605-88 - Maintenance of records; submittal of information.

Code of Federal Regulations, 2013 CFR

2013-07-01

..., pressure increase across the pump, and the temperature set point of the temperature control system. (2... samples are being collected. (3) Humidity of dilution air. (4) Manufacturer, model, type and serial number..., ambient temperature and humidity. (2) Data and time of day. (ii) In lieu of recording test equipment...

Behavioral thermoregulation in Hemigrapsus nudus, the amphibious purple shore crab.

PubMed

McGaw, I J

2003-02-01

The thermoregulatory behavior of Hemigrapsus nudus, the amphibious purple shore crab, was examined in both aquatic and aerial environments. Crabs warmed and cooled more rapidly in water than in air. Acclimation in water of 16 degrees C (summer temperatures) raised the critical thermal maximum temperature (CTMax); acclimation in water of 10 degrees C (winter temperatures) lowered the critical thermal minimum temperature (CTMin). The changes occurred in both water and air. However, these survival regimes did not reflect the thermal preferences of the animals. In water, the thermal preference of crabs acclimated to 16 degrees C was 14.6 degrees C, and they avoided water warmer than 25.5 degrees C. These values were significantly lower than those of the crabs acclimated to 10 degrees C; these animals demonstrated temperature preferences for water that was 17 degrees C, and they avoided water that was warmer than 26.9 degrees C. This temperature preference was also exhibited in air, where 10 degrees C acclimated crabs exited from under rocks at a temperature that was 3.2 degrees C higher than that at which the 16 degrees C acclimated animals responded. This behavioral pattern was possibly due to a decreased thermal tolerance of 16 degrees C acclimated crabs, related with the molting process. H. nudus was better able to survive prolonged exposure to cold temperatures than to warm temperatures, and there was a trend towards lower exit temperatures with the lower acclimation (10 degrees C) temperature. Using a complex series of behaviors, the crabs were able to precisely control body temperature independent of the medium, by shuttling between air and water. The time spent in either air or water was influenced more strongly by the temperature than by the medium. In the field, this species may experience ranges in temperatures of up to 20 degrees C; however, it is able to utilize thermal microhabitats underneath rocks to maintain its body temperature within fairly narrow limits.

Microwave antenna array for prostrate hyperthermia

NASA Astrophysics Data System (ADS)

Trembly, B. Stuart; Hoopes, P. Jack; Moodie, Karen L.; Dvinsky, Arik S.

1999-05-01

A pair of microwave applicators was developed to produce controlled elevation of temperature in the prostate. One applicator was designed for placement in the urethra; it has a diameter of 6 mm and is flexible. This applicator incorporates a choked, resonant microwave dipole with an omnidirectional heating pattern and an air cooling system to control the temperature of the urothelium. The second applicator was designed for placement in the rectum; it has a diameter of 18 mm and is rigid. It incorporates an eccentric, choked, resonant microwave dipole that radiates toward the prostate with a front-to-back power ratio of about twenty. An air cooling system controls the temperature of the rectal mucosa. The applicators are driven at 915 MHz with a phase difference chosen to produce the maximum temperature in the central prostate. We heated the prostates of eight canine subjects with the transurethral and transrectal applicators. After one or two months of followup in four subjects, the prostates and surrounding tissues were evaluated histologically. We present experimental measurements of the power deposition patterns of the applicators and the 3D temperature distributions in vivo, and we correlate the thermal dose with histopathological observations.

Demand Controlled Economizer Cycles: A Direct Digital Control Scheme for Heating, Ventilating, and Air Conditioning Systems,

DTIC Science & Technology

1984-05-01

Control Ignored any error of 1/10th degree or less. This was done by setting the error term E and the integral sum PREINT to zero If then absolute value of...signs of two errors jeq tdiff if equal, jump clr @preint else zero integal sum tdiff mov @diff,rl fetch absolute value of OAT-RAT ci rl,25 is...includes a heating coil and thermostatic control to maintain the air in this path at an elevated temperature, typically around 80 degrees Farenheit (80 F

Effect of air humidification on the sick building syndrome and perceived indoor air quality in hospitals: a four month longitudinal study.

PubMed Central

Nordström, K; Norbäck, D; Akselsson, R

1994-01-01

The sensation of dryness and irritation is essential in the sick building syndrome (SBS), and such symptoms are common in both office and hospital employees. In Scandinavia, the indoor relative humidity in well ventilated buildings is usually in the range 10-35% in winter. The aim of this study was to evaluate the effect of steam air humidification on SBS and perceived air quality during the heating season. The study base consisted of a dynamic population of 104 hospital employees, working in four new and well ventilated geriatric hospital units in southern Sweden. Air humidification raised the relative air humidity to 40-45% in two units during a four months period, whereas the other two units served as controls with relative humidity from 25-35%. Symptoms and perceived indoor air quality were measured before and after the study period by a standardised self administered questionnaire. The technical measurements comprised room temperature, air humidity, static electricity, exhaust air flow, aerosols, microorganisms, and volatile organic compounds in the air. The most pronounced effect of the humidification was a significant decrease of the sensation of air dryness, static electricity, and airway symptoms. After four months of air humidification during the heating season, 24% reported a weekly sensation of dryness in humidified units, compared with 73% in controls. No significant changes in symptoms of SBS or perceived air quality over time were found in the control group. The room temperature in all units was between 21-23 degrees C, and no significant effect of air humidification on the air concentration of aerosols or volatile organic compounds was found. No growth of microorganisms was found in the supply air ducts, and no legionella bacteria were found in the supply water of the humidifier. Air humidification, however, significantly reduced the measured personal exposure to static electricity. It is concluded that air humidification during the heating season in colder climates can decrease symptoms of SBS and perception of dry air. PMID:8000493

Simulation analysis of temperature control on RCC arch dam of hydropower station

NASA Astrophysics Data System (ADS)

XIA, Shi-fa

2017-12-01

The temperature analysis of roller compacted concrete (RCC) dam plays an important role in their design and construction. Based on three-dimensional finite element method, in the computation of temperature field, many cases are included, such as air temperature, elevated temperature by cement hydration heat, concrete temperature during placing, the influence of water in the reservoir, and boundary temperature. According to the corresponding parameters of RCC arch dam, the analysis of temperature field and stress field during the period of construction and operation is performed. The study demonstrates that detailed thermal stress analysis should be performed for RCC dams to provide a basis to minimize and control the occurrence of thermal cracking.

Effects of respirator ambient air cooling on thermophysiological responses and comfort sensations.

PubMed

Caretti, David M; Barker, Daniel J

2014-01-01

This investigation assessed the thermophysiological and subjective impacts of different respirator ambient air cooling options while wearing chemical and biological personal protective equipment in a warm environment (32.7 ± 0.4°C, 49.6 ± 6.5% RH). Ten volunteers participated in 90-min heat exposure trials with and without respirator (Control) wear and performed computer-generated tasks while seated. Ambient air cooling was provided to respirators modified to blow air to the forehead (FHC) or to the forehead and the breathing zone (BZC) of a full-facepiece air-purifying respirator using a low-flow (45 L·min(-1)) mini-blower. An unmodified respirator (APR) trial was also completed. The highest body temperatures (TTY) and least favorable comfort ratings were observed for the APR condition. With ambient cooling over the last 60 min of heat exposure, TTY averaged 37.4 ± 0.6°C for Control, 38.0 ± 0.4°C for APR, 37.8 ± 0.5°C for FHC, and 37.6 ± 0.7°C for BZC conditions independent of time. Both the FHC and BZC ambient air cooling conditions reduced facial skin temperatures, reduced the rise in body temperatures, and led to more favorable subjective comfort and thermal sensation ratings over time compared to the APR condition; however statistical differences among conditions were inconsistent. Independent of exposure time, average breathing apparatus comfort scores with BZC (7.2 ± 2.5) were significantly different from both Control (8.9 ± 1.4) and APR (6.5 ± 2.2) conditions when ambient cooling was activated. These findings suggest that low-flow ambient air cooling of the face under low work rate conditions and mild hyperthermia may be a practical method to minimize the thermophysiological strain and reduce perceived respirator discomfort.

Line shape parameters of air-broadened water vapor transitions in the ν 1 and ν 3 spectral region

DOE PAGES

Malathy Devi, V.; Gamache, Robert R.; Vispoel, Bastien; ...

2017-11-26

A Bruker IFS-120HR Fourier transform spectrometer located at the Pacific Northwest National Laboratory (PNNL) in Richland, Washington was used to record a series of spectra of pure H 2O and air-broadened H 2O in the regions of the ν 1 and ν 3 bands (3450–4000 cm -1) at different pressures, temperatures and volume mixing ratios of H 2O in air. Eighteen high-resolution, high signal-to-noise (S/N) ratio absorption spectra were recorded at T = 268, 296 and 353 K using two temperature-controlled absorption cells with path lengths of 9.906(1) and 19.95(1) cm. Furthermore, the resolution of the spectra recorded with themore » 9.906 cm and 19.95 cm absorption cells was 0.006 and 0.008 cm -1, respectively. A multispectrum nonlinear least squares fitting technique was employed to fit all the eighteen spectra simultaneously to retrieve 313 accurate line positions, 315 intensities, 229 Lorentz air-broadened half-width and 213 air-shift coefficients and their temperature dependences (136 for air-broadened width and 128 for air-shift coefficients, respectively). Room temperature self-broadened half-width coefficients for 209 transitions and self-shift coefficients for 106 transitions were also measured. Line mixing coefficients were experimentally determined for isolated sets of 10 transition pairs for H 2O-air and 8 transition pairs for H 2O-H 2O using the off-diagonal relaxation matrix element formalism, and 85 quadratic speed dependence parameters were measured. Modified Complex Robert-Bonamy (MCRB) calculations of self-, and air-broadened (from N 2- and O 2-broadening) half-width and air-shift coefficients, and temperature dependence exponents of air-broadened half-width coefficients are made. Finally, the measurements and calculations are compared with each other and with similar parameters reported in the literature.« less

Line shape parameters of air-broadened water vapor transitions in the ν1 and ν3 spectral region

NASA Astrophysics Data System (ADS)

Malathy Devi, V.; Gamache, Robert R.; Vispoel, Bastien; Renaud, Candice L.; Chris Benner, D.; Smith, Mary Ann H.; Blake, Thomas A.; Sams, Robert L.

2018-06-01

A Bruker IFS-120HR Fourier transform spectrometer located at the Pacific Northwest National Laboratory (PNNL) in Richland, Washington was used to record a series of spectra of pure H2O and air-broadened H2O in the regions of the ν1 and ν3 bands (3450-4000 cm-1) at different pressures, temperatures and volume mixing ratios of H2O in air. Eighteen high-resolution, high signal-to-noise (S/N) ratio absorption spectra were recorded at T = 268, 296 and 353 K using two temperature-controlled absorption cells with path lengths of 9.906(1) and 19.95(1) cm. The resolution of the spectra recorded with the 9.906 cm and 19.95 cm absorption cells was 0.006 and 0.008 cm-1, respectively. A multispectrum nonlinear least squares fitting technique was employed to fit all the eighteen spectra simultaneously to retrieve 313 accurate line positions, 315 intensities, 229 Lorentz air-broadened half-width and 213 air-shift coefficients and their temperature dependences (136 for air-broadened width and 128 for air-shift coefficients, respectively). Room temperature self-broadened half-width coefficients for 209 transitions and self-shift coefficients for 106 transitions were also measured. Line mixing coefficients were experimentally determined for isolated sets of 10 transition pairs for H2O-air and 8 transition pairs for H2O-H2O using the off-diagonal relaxation matrix element formalism, and 85 quadratic speed dependence parameters were measured. Modified Complex Robert-Bonamy (MCRB) calculations of self-, and air-broadened (from N2- and O2-broadening) half-width and air-shift coefficients, and temperature dependence exponents of air-broadened half-width coefficients are made. The measurements and calculations are compared with each other and with similar parameters reported in the literature.

Line shape parameters of air-broadened water vapor transitions in the ν 1 and ν 3 spectral region

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

Malathy Devi, V.; Gamache, Robert R.; Vispoel, Bastien

A Bruker IFS-120HR Fourier transform spectrometer located at the Pacific Northwest National Laboratory (PNNL) in Richland, Washington was used to record a series of spectra of pure H 2O and air-broadened H 2O in the regions of the ν 1 and ν 3 bands (3450–4000 cm -1) at different pressures, temperatures and volume mixing ratios of H 2O in air. Eighteen high-resolution, high signal-to-noise (S/N) ratio absorption spectra were recorded at T = 268, 296 and 353 K using two temperature-controlled absorption cells with path lengths of 9.906(1) and 19.95(1) cm. Furthermore, the resolution of the spectra recorded with themore » 9.906 cm and 19.95 cm absorption cells was 0.006 and 0.008 cm -1, respectively. A multispectrum nonlinear least squares fitting technique was employed to fit all the eighteen spectra simultaneously to retrieve 313 accurate line positions, 315 intensities, 229 Lorentz air-broadened half-width and 213 air-shift coefficients and their temperature dependences (136 for air-broadened width and 128 for air-shift coefficients, respectively). Room temperature self-broadened half-width coefficients for 209 transitions and self-shift coefficients for 106 transitions were also measured. Line mixing coefficients were experimentally determined for isolated sets of 10 transition pairs for H 2O-air and 8 transition pairs for H 2O-H 2O using the off-diagonal relaxation matrix element formalism, and 85 quadratic speed dependence parameters were measured. Modified Complex Robert-Bonamy (MCRB) calculations of self-, and air-broadened (from N 2- and O 2-broadening) half-width and air-shift coefficients, and temperature dependence exponents of air-broadened half-width coefficients are made. Finally, the measurements and calculations are compared with each other and with similar parameters reported in the literature.« less

Design and Applications of a Climatic Chamber for in-situ Neutron Imaging Experiments

NASA Astrophysics Data System (ADS)

Mannes, David; Schmid, Florian; Wehmann, Timon; Lehmann, Eberhard

Due to the high sensitivity for hydrogen, the detection and quantification of moisture and moisture transport processes are some of the key topics in neutron imaging. Especially when dealing with hygroscopic material, such as wood and other porous media, it is crucial for quantitative analyses to know and control the ambient conditions of the sample precisely. In this work, a neutron transparent climatic chamber is presented, which was designed and built for the imaging facilities at the Paul Scherrer Institut (PSI), Villigen (CH). The air-conditioned measuring system consists of the actual sample chamber and a moisture generator providing air with adjustable temperature and relative humidity (%RH) (up to a dew point temperature of 70 °C). The two components are connected with a flexible tube, which features insulation, a heating system and temperature sensors to prevent condensation within the tube. The sample chamber itself is equipped with neutron transparent windows, insulating double walls with three feed-through openings for the rotation stage, sensors for humidity and temperature. Thermoelectric modules allow to control the chamber temperature in the range of -20 °C to 100 °C. The chamber allows to control the climatic conditions either in a static mode (stable temperature and %RH) or in dynamic mode (humidity or temperature cycles). The envisaged areas of application are neutron radiography and tomography investigations of dynamic processes in building materials (e.g. wood, concrete), food science and any other application necessitating the control of the climatic conditions.

Control of insects and mites in grain using a high temperature/short time (HTST) technique.

PubMed

Mourier; Poulsen

2000-07-01

Wheat infested with grain mites (Acari) and Sitophilus granarius, and maize infested with Prostephanus truncatus, were exposed to hot air in a CIMBRIA HTST Microline toaster((R)). Inlet temperatures of the hot air were in the range of 150-750 degrees C decreasing to outlet temperatures in the range of 100-300 degrees C during the exposure period. A rotating drum, connected to a natural-gas burner was fed with grain which was in constant movement along the drum and thereby mixed thoroughly during the process. The capacity of the toaster was 1000 kg per hour.Complete control of grain mites and adult S. granarius in wheat was obtained with an inlet temperature of 300-350 degrees C and an average residence time in the drum of 6 s. More than 99% mortality was obtained for all stages of S. granarius with an inlet temperature of 300-350 degrees C and an average exposure period of 40 s. For control of P. truncatus in maize, an inlet temperature of 700 degrees C resulted in a complete disinfestation when the exposure time was 19 s.The reduction in grain moisture content was 0.5-1% at treatments giving 100% control. Germination tests indicate that it is possible to choose a combination of inlet temperatures and exposure periods which effectively kills mites and insects in small grains, without harming the functional properties of the grain.Economy of the method was considered to be competitive with fumigation using phosphine.

Visiting a sauna: does inhaling hot dry air reduce common cold symptoms? A randomised controlled trial.

PubMed

Pach, Daniel; Knöchel, Bettina; Lüdtke, Rainer; Wruck, Katja; Willich, Stefan N; Witt, Claudia M

To compare the efficacy of applying hot dry air versus dry air at room temperature to the throat of patients with a newly acquired common cold using a symptom severity score. A randomised single-blind controlled trial with a treatment duration of 3 days and a follow-up period of 4 days was conducted at a sauna in Berlin, Germany. Between November 2007 and March 2008 and between September 2008 and April 2009, 157 patients with symptoms of the common cold were randomly assigned to an intervention group (n=80) and a control group (n=77). Participants in the intervention group inhaled hot dry air within a hot sauna, dressed in a winter coat, whereas participants in the control group inhaled dry air at room temperature within a hot sauna, also dressed in a winter coat. Area under the curve (AUC) summarising symptom severity over time (Days 2, 3, 5 and 7), symptom severity scores for individual days, intake of medication for the common cold and general ill feeling. No significant difference between groups was observed for AUC representing symptom severity over time (intervention group mean, 31.2 [SEM, 1.8]; control group mean, 35.1 [SEM, 2.3]; group difference, -3.9 [95% CI, -9.7 to 1.9]; P=0.19). However, significant differences between groups were found for medication use on Day 1 (P=0.01), symptom severity score on Day 2 (P=0.04), and participants' ratings of the effectiveness of the therapy on Day 7 (P=0.03). Inhaling hot air while in a sauna has no significant impact on overall symptom severity of the common cold. ClinicalTrials.gov identifier NCT00552981.

Preliminary simulation study on regional climate change in Xinjiang, China

NASA Astrophysics Data System (ADS)

Yuan, Chunqiong; Guo, Qingyu; Xie, Hongbing; Pan, Xiaoling; Anabiek, Subai

2004-01-01

Under the conditions of global warming, the degenerated ecological environment has threatened human survival. Therefore, people will gradually pay more attention to the environmental problem of climate change. This paper analyzes the distribution features of air temperature, relative humidity (precipitation), and the horizontal stream field in Xinjiang for July 1997. In order to do the integration of one month (July, 1997) we ran the model NCAP/PENN MM5V3. Data from WLCCD (the latest World Land Cover Characteristics Database) was used to relate the two research domains of the model, and also to replace the vegetation in the MM5. The data in the WWLCD depends on the actual land surface characteristics. It was found that the general law of air temperature, relative humidity (precipitation) and the horizontal stream field of 1000hPa in Xinjiang in July of 1997 by means of the model. The mean regional data for July helped prefect the theory that humans are controlling the ecological environment in order to prevent and control desertification. Among these results, the simulated air temperature was the best.

Air - water temperature relationships in the trout streams of southeastern Minnesota’s carbonate - sandstone landscape

USGS Publications Warehouse

Krider, Lori A.; Magner, Joseph A.; Perry, Jim; Vondracek, Bruce C.; Ferrington, Leonard C.

2013-01-01

Carbonate-sandstone geology in southeastern Minnesota creates a heterogeneous landscape of springs, seeps, and sinkholes that supply groundwater into streams. Air temperatures are effective predictors of water temperature in surface-water dominated streams. However, no published work investigates the relationship between air and water temperatures in groundwater-fed streams (GWFS) across watersheds. We used simple linear regressions to examine weekly air-water temperature relationships for 40 GWFS in southeastern Minnesota. A 40-stream, composite linear regression model has a slope of 0.38, an intercept of 6.63, and R2 of 0.83. The regression models for GWFS have lower slopes and higher intercepts in comparison to surface-water dominated streams. Regression models for streams with high R2 values offer promise for use as predictive tools for future climate conditions. Climate change is expected to alter the thermal regime of groundwater-fed systems, but will do so at a slower rate than surface-water dominated systems. A regression model of intercept vs. slope can be used to identify streams for which water temperatures are more meteorologically than groundwater controlled, and thus more vulnerable to climate change. Such relationships can be used to guide restoration vs. management strategies to protect trout streams.

Control installation for the proportioning of a secondary air quantity for improvement of the combustion in internal combustion engines or the afterburning of the exhaust gases of internal combustion engines

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

Bockelmann, W.; Groezinger, H.; Woebky, P.U.

1977-01-04

A control installation is described for the dosing or proportioning of a secondary air quantity for the improvement of combustion in internal combustion engines, or the after-burning of the exhaust gases of internal combustion engines. An auxiliary arrangement is responsive to an emergency signal for effecting the prompt shutting-off of the secondary air. The emergency signal may be initiated in response to a failure in the ignition voltage of the internal combustion engine; an increase in the hydrocarbon content of the exhaust gases; a disparity between the position of the mixture dosing element and the engine rotational speed; the exceedingmore » of a limiting temperature in the exhaust gas manifold; or the exceeding of a limiting temperature in the afterburner.« less

109. EAST WALL OF MECHANICAL EQUIPMENT ROOM (201), LSB (BLDG. ...

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

109. EAST WALL OF MECHANICAL EQUIPMENT ROOM (201), LSB (BLDG. 751): TEMPERATURE, FLOW RATE, AND HUMIDITY MONITORING CONTROLS FOR SYSTEM 1 AND SYSTEM 2 AIR HANDLING - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 East, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

92. EAST WALL OF MECHANICAL EQUIPMENT ROOM (101), LSB (BLDG. ...

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

92. EAST WALL OF MECHANICAL EQUIPMENT ROOM (101), LSB (BLDG. 770). TEMPERATURE, FLOW RATE, AND HUMIDITY MONITORING CONTROLS FOR SYSTEM 1 AND SYSTEM 2 AIR HANDLING. - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 West, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

System for controlling child safety seat environment

NASA Technical Reports Server (NTRS)

Elrod, Susan V. (Inventor); Dabney, Richard W. (Inventor)

2008-01-01

A system is provided to control the environment experienced by a child in a child safety seat. Each of a plurality of thermoelectric elements is individually controllable to be one of heated and cooled relative to an ambient temperature. A first portion of the thermoelectric elements are positioned on the child safety seat such that a child sitting therein is positioned thereover. A ventilator coupled to the child safety seat moves air past a second portion of the thermoelectric elements and filters the air moved therepast. One or more jets coupled to the ventilator receive the filtered air. Each jet is coupled to the child safety seat and can be positioned to direct the heated/cooled filtered air to the vicinity of the head of the child sitting in the child safety seat.

Automotive Stirling engine system component review

NASA Technical Reports Server (NTRS)

Hindes, Chip; Stotts, Robert

1987-01-01

The design and testing of the power and combustion control system for the basic Stirling engine, Mod II, are examined. The power control system is concerned with transparent operation, and the Mod II uses engine working gas pressure variation to control the power output of the engine. The main components of the power control system, the power control valve, the pump-down system, and the hydrogen stable system, are described. The combustion control system consists of a combustion air supply system and an air/fuel ratio control system, and the system is to maintain constant heater head temperature, and to maximize combustion efficiency and to minimize exhaust emissions.

Thermal effects on bacterial bioaerosols in continuous air flow.

PubMed

Jung, Jae Hee; Lee, Jung Eun; Kim, Sang Soo

2009-08-01

Exposure to bacterial bioaerosols can have adverse effects on health, such as infectious diseases, acute toxic effects, and allergies. The search for ways of preventing and curing the harmful effects of bacterial bioaerosols has created a strong demand for the study and development of an efficient method of controlling bioaerosols. We investigated the thermal effects on bacterial bioaerosols of Escherichia coli and Bacillus subtilis by using a thermal electric heating system in continuous air flow. The bacterial bioaerosols were exposed to a surrounding temperature that ranged from 20 degrees C to 700 degrees C for about 0.3 s. Both E. coli and B. subtilis vegetative cells were rendered more than 99.9% inactive at 160 degrees C and 350 degrees C of wall temperature of the quartz tube, respectively. Although the data on bacterial injury showed that the bacteria tended to sustain greater damage as the surrounding temperature increased, Gram-negative E. coli was highly sensitive to structural injury but Gram-positive B. subtilis was slightly more sensitive to metabolic injury. In addition, the inactivation of E. coli endotoxins was found to range from 9.2% (at 200 degrees C) to 82.0% (at 700 degrees C). However, the particle size distribution and morphology of both bacterial bioaerosols were maintained, despite exposure to a surrounding temperature of 700 degrees C. Our results show that thermal heating in a continuous air flow can be used with short exposure time to control bacterial bioaerosols by rendering the bacteria and endotoxins to a large extent inactive. This result could also be useful for developing more effective thermal treatment strategies for use in air purification or sterilization systems to control bioaerosols.

Applying Energy Conservation Retrofits to Standard Army Buildings: Project Design and Initial Energy Data

DTIC Science & Technology

1988-07-01

Window Area 33 24 New Exterior Doors of Dining Hall 34 25 New Window Panels of Dining Hall 34 I 26 New Pneumatic Reset Controllers of Dining Hall 35 27...of conditioned air that is exhausted from the building soace during hood operation. HW temperature reset A new heating system controller from Taylor...to be as high. The converse is true as outdoor temperatures get colder. Resetting the temperature of the heating hot water with changes in the outdoor

Air-ice CO2 fluxes and pCO2 dynamics in the Arctic coastal area (Amundsen Gulf, Canada)

NASA Astrophysics Data System (ADS)

Geilfus, Nicolas-Xavier; Tison, Jean Louis; Carnat, Gauthier; Else, Brent; Borges, Alberto V.; Thomas, Helmuth; Shadwick, Elizabeth; Delille, Bruno

2010-05-01

Sea ice covers about 7% of the Earth surface at its maximum seasonal extent. For decades sea ice was assumed to be an impermeable and inert barrier for air - sea exchange of CO2 so that global climate models do not include CO2 exchange between the oceans and the atmosphere in the polar regions. However, uptake of atmospheric CO2 by sea ice cover was recently reported raising the need to further investigate pCO2 dynamics in the marine cryosphere realm and related air-ice CO2 fluxes. In addition, budget of CO2 fluxes are poorly constrained in high latitudes continental shelves [Borges et al., 2006]. We report measurements of air-ice CO2 fluxes above the Canadian continental shelf and compare them to previous measurements carried out in Antarctica. We carried out measurements of pCO2 within brines and bulk ice, and related air-ice CO2 fluxes (chamber method) in Antarctic first year pack ice ("Sea Ice Mass Balance in Antarctica -SIMBA" drifting station experiment September - October 2007) and in Arctic first year land fast ice ("Circumpolar Flaw Lead" - CFL, April - June 2008). These 2 experiments were carried out in contrasted sites. SIMBA was carried out on sea ice in early spring while CFL was carried out in from the middle of the winter to the late spring while sea ice was melting. Both in Arctic and Antarctic, no air-ice CO2 fluxes were detected when sea ice interface was below -10°C. Slightly above -10°C, fluxes toward the atmosphere were observed. In contrast, at -7°C fluxes from the atmosphere to the ice were significant. The pCO2 of the brine exhibits a same trend in both hemispheres with a strong decrease of the pCO2 anti-correlated with the increase of sea ice temperature. The pCO2 shifted from a large over-saturation at low temperature to a marked under-saturation at high temperature. These air-ice CO2 fluxes are partly controlled by the permeability of the air-ice interface, which depends of the temperature of this one. Moreover, air-ice CO2 fluxes are driven by the air-ice pCO2 gradient. Hence, while the temperature is a leading factor in controlling magnitude of air-ice CO2 fluxes, pCO2 of the ice controls both magnitude and direction of fluxes. However, pCO2 in Arctic is significantly higher than in Antarctica. This difference could be due to a higher level of organic matter in Arctic. The degradation of this organic matter fuel CO2 efflux from the ice to the atmosphere in early spring. We observed evidence of CaCO3 precipitation, but only at the top of the ice. Implications in term of air-ice CO2 transfer of such CaCO3 precipitation will be discussed. In addition, salt-rich snow appears to strongly affect air-ice CO2 fluxes in the arctic. Borges, A. V., et al. (2006), Carbon dioxide in European coastal waters, Estuar. Coast. Shelf Sci., 70(3), 375-387.

Short-range optical air data measurements for aircraft control using rotational Raman backscatter.

PubMed

Fraczek, Michael; Behrendt, Andreas; Schmitt, Nikolaus

2013-07-15

A first laboratory prototype of a novel concept for a short-range optical air data system for aircraft control and safety was built. The measurement methodology was introduced in [Appl. Opt. 51, 148 (2012)] and is based on techniques known from lidar detecting elastic and Raman backscatter from air. A wide range of flight-critical parameters, such as air temperature, molecular number density and pressure can be measured as well as data on atmospheric particles and humidity can be collected. In this paper, the experimental measurement performance achieved with the first laboratory prototype using 532 nm laser radiation of a pulse energy of 118 mJ is presented. Systematic measurement errors and statistical measurement uncertainties are quantified separately. The typical systematic temperature, density and pressure measurement errors obtained from the mean of 1000 averaged signal pulses are small amounting to < 0.22 K, < 0.36% and < 0.31%, respectively, for measurements at air pressures varying from 200 hPa to 950 hPa but constant air temperature of 298.95 K. The systematic measurement errors at air temperatures varying from 238 K to 308 K but constant air pressure of 946 hPa are even smaller and < 0.05 K, < 0.07% and < 0.06%, respectively. A focus is put on the system performance at different virtual flight altitudes as a function of the laser pulse energy. The virtual flight altitudes are precisely generated with a custom-made atmospheric simulation chamber system. In this context, minimum laser pulse energies and pulse numbers are experimentally determined, which are required using the measurement system, in order to meet measurement error demands for temperature and pressure specified in aviation standards. The aviation error margins limit the allowable temperature errors to 1.5 K for all measurement altitudes and the pressure errors to 0.1% for 0 m and 0.5% for 13000 m. With regard to 100-pulse-averaged temperature measurements, the pulse energy using 532 nm laser radiation has to be larger than 11 mJ (35 mJ), regarding 1-σ (3-σ) uncertainties at all measurement altitudes. For 100-pulse-averaged pressure measurements, the laser pulse energy has to be larger than 95 mJ (355 mJ), respectively. Based on these experimental results, the laser pulse energy requirements are extrapolated to the ultraviolet wavelength region as well, resulting in significantly lower pulse energy demand of 1.5 - 3 mJ (4-10 mJ) and 12-27 mJ (45-110 mJ) for 1-σ (3-σ) 100-pulse-averaged temperature and pressure measurements, respectively.

Photosynthesis of young apple trees in response to low sink demand under different air temperatures.

PubMed

Fan, Pei G; Li, Lian S; Duan, Wei; Li, Wei D; Li, Shao H

2010-03-01

Gas exchange, chlorophyll fluorescence, photosynthetic end products and related enzymes in source leaves in response to low sink demand after girdling to remove the root sink were assessed in young apple trees (Malus pumila) grown in two greenhouses with different air temperatures for 5 days. Compared with the non-girdled control in the low-temperature greenhouse (diurnal maximum air temperature <32 degrees C), low sink demand resulted in lower net photosynthetic rate (P(n)), stomatal conductance (g(s)) and transpiration rate (E) but higher leaf temperature on Day 5, while in the high-temperature greenhouse (diurnal maximum air temperature >36 degrees C), P(n), g(s) and E declined from Day 3 onwards. Moreover, gas exchange responded more to low sink demand in the high-temperature greenhouse than in the low-temperature greenhouse. Decreased P(n) at low sink demand was accompanied by lower intercellular CO(2) concentrations in the low-temperature greenhouse. However, decreased maximal photochemical efficiency, potential activity, efficiency of excitation capture, actual efficiency and photochemical quenching, with increased minimal fluorescence and non-photochemical quenching of photosystem II (PSII), were observed in low sink demand leaves only in the high-temperature greenhouse. In addition, low sink demand increased leaf starch and soluble carbohydrate content in both greenhouses but did not result in lower activity of enzymes involved in metabolism. Thus, decreased P(n) under low sink demand was independent of a direct effect of end-product feedback but rather depended on a high temperature threshold. The lower P(n) was likely due to stomatal limitation in the low-temperature greenhouse, but mainly due to non-stomatal limitation in the high-temperature greenhouse.

Impacts of Lowered Urban Air Temperatures on Precursor Emission and Ozone Air Quality.

PubMed

Taha, Haider; Konopacki, Steven; Akbari, Hashem

1998-09-01

Meteorological, photochemical, building-energy, and power plant simulations were performed to assess the possible precursor emission and ozone air quality impacts of decreased air temperatures that could result from implementing the "cool communities" concept in California's South Coast Air Basin (SoCAB). Two pathways are considered. In the direct pathway, a reduction in cooling energy use translates into reduced demand for generation capacity and, thus, reduced precursor emissions from electric utility power plants. In the indirect pathway, reduced air temperatures can slow the atmospheric production of ozone as well as precursor emission from anthropogenic and biogenic sources. The simulations suggest small impacts on emissions following implementation of cool communities in the SoCAB. In summer, for example, there can be reductions of up to 3% in NO x emissions from in-basin power plants. The photochemical simulations suggest that the air quality impacts of these direct emission reductions are small. However, the indirect atmospheric effects of cool communities can be significant. For example, ozone peak concentrations can decrease by up to 11% in summer and population-weighted exceedance exposure to ozone above the California and National Ambient Air Quality Standards can decrease by up to 11 and 17%, respectively. The modeling suggests that if these strategies are combined with others, such as mobile-source emission control, the improvements in ozone air quality can be substantial.

N Vibrational Temperatures and OH Number Density Measurements in a NS Pulse Discharge Hydrogen-Air Plasmas

NASA Astrophysics Data System (ADS)

Hung, Yichen; Winters, Caroline; Jans, Elijah R.; Frederickson, Kraig; Adamovich, Igor V.

2017-06-01

This work presents time-resolved measurements of nitrogen vibrational temperature, translational-rotational temperature, and absolute OH number density in lean hydrogen-air mixtures excited in a diffuse filament nanosecond pulse discharge, at a pressure of 100 Torr and high specific energy loading. The main objective of these measurements is to study a possible effect of nitrogen vibrational excitation on low-temperature kinetics of HO2 and OH radicals. N2 vibrational temperature and gas temperature in the discharge and the afterglow are measured by ns broadband Coherent Anti-Stokes Scattering (CARS). Hydroxyl radical number density is measured by Laser Induced Fluorescence (LIF) calibrated by Rayleigh scattering. The results show that the discharge generates strong vibrational nonequilibrium in air and H2-air mixtures for delay times after the discharge pulse of up to 1 ms, with peak vibrational temperature of Tv ≈ 2000 K at T ≈ 500 K. Nitrogen vibrational temperature peaks ≈ 200 μs after the discharge pulse, before decreasing due to vibrational-translational relaxation by O atoms (on the time scale of a few hundred μs) and diffusion (on ms time scale). OH number density increases gradually after the discharge pulse, peaking at t 100-300 μs and decaying on a longer time scale, until t 1 ms. Both OH rise time and decay time decrease as H2 fraction in the mixture is increased from 1% to 5%. OH number density in a 1% H2-air mixture peaks at approximately the same time as vibrational temperature in air, suggesting that OH kinetics may be affected by N2 vibrational excitation. However, preliminary kinetic modeling calculations demonstrate that OH number density overshoot is controlled by known reactions of H and O radicals generated in the plasma, rather than by dissociation by HO2 radical in collisions with vibrationally excited N2 molecules, as has been suggested earlier. Additional measurements at higher specific energy loadings and kinetic modeling calculations are underway.

Air oxidation of Zircaloy-4 in the 600-1000 °C temperature range: Modeling for ASTEC code application

NASA Astrophysics Data System (ADS)

Coindreau, O.; Duriez, C.; Ederli, S.

2010-10-01

Progress in the treatment of air oxidation of zirconium in severe accident (SA) codes are required for a reliable analysis of severe accidents involving air ingress. Air oxidation of zirconium can actually lead to accelerated core degradation and increased fission product release, especially for the highly-radiotoxic ruthenium. This paper presents a model to simulate air oxidation kinetics of Zircaloy-4 in the 600-1000 °C temperature range. It is based on available experimental data, including separate-effect experiments performed at IRSN and at Forschungszentrum Karlsruhe. The kinetic transition, named "breakaway", from a diffusion-controlled regime to an accelerated oxidation is taken into account in the modeling via a critical mass gain parameter. The progressive propagation of the locally initiated breakaway is modeled by a linear increase in oxidation rate with time. Finally, when breakaway propagation is completed, the oxidation rate stabilizes and the kinetics is modeled by a linear law. This new modeling is integrated in the severe accident code ASTEC, jointly developed by IRSN and GRS. Model predictions and experimental data from thermogravimetric results show good agreement for different air flow rates and for slow temperature transient conditions.

Controlling mechanisms of moisture diffusion in convective drying of leather

NASA Astrophysics Data System (ADS)

Benmakhlouf, Naima; Azzouz, Soufien; Monzó-Cabrera, Juan; Khdhira, Hechmi; ELCafsi, Afif

2017-04-01

Leather manufacturing involves a crucial energy-intensive drying stage in the finishing process to remove its residual moisture. It occurs several times in the tanning course. As it is the target of this paper to depict an experimental way to determine moisture diffusion in the convective drying of leather. The effective diffusion coefficient is estimated by a method derived from Fick's law and by analytic method. The effective diffusion coefficients are obtained from drying tests and the diffusivity behaviour is studied versus the controlling parameter such as the convective airflow temperature. The experiments were conducted at hot air temperatures of 40, 45, 50, 55 and 60 °C and hot air speed of 1 m/s. The hot air temperature had significant effect on the effective moisture diffusivity of the leather sample. The average effective moisture diffusivity in rosehip ranged between 5.87 × 10-11 and 14.48 × 10-11 m2/s for leather at the temperatures studied. Activation energy for convective drying was found to be 38.46 kJ/mol for leather. The obtained results fully confirm the theoretical study in which an exponentially increasing relationship between effective diffusivity and temperature is predicted. The results of this study provide a better understanding of the drying mechanisms and may lead to a series of recommendations for leather drying optimization. It opens the possibility for further investigations on the description of drying conditions.

Interfacial material for solid oxide fuel cell

DOEpatents

Baozhen, Li; Ruka, Roswell J.; Singhal, Subhash C.

1999-01-01

Solid oxide fuel cells having improved low-temperature operation are disclosed. In one embodiment, an interfacial layer of terbia-stabilized zirconia is located between the air electrode and electrolyte of the solid oxide fuel cell. The interfacial layer provides a barrier which controls interaction between the air electrode and electrolyte. The interfacial layer also reduces polarization loss through the reduction of the air electrode/electrolyte interfacial electrical resistance. In another embodiment, the solid oxide fuel cell comprises a scandia-stabilized zirconia electrolyte having high electrical conductivity. The scandia-stabilized zirconia electrolyte may be provided as a very thin layer in order to reduce resistance. The scandia-stabilized electrolyte is preferably used in combination with the terbia-stabilized interfacial layer. The solid oxide fuel cells are operable over wider temperature ranges and wider temperature gradients in comparison with conventional fuel cells.

The altitudinal temperature lapse rates applied to high elevation rockfalls studies in the Western European Alps

NASA Astrophysics Data System (ADS)

Nigrelli, Guido; Fratianni, Simona; Zampollo, Arianna; Turconi, Laura; Chiarle, Marta

2018-02-01

Temperature is one of the most important aspects of mountain climates. The relationships between air temperature and rockfalls at high-elevation sites are very important to know, but are also very difficult to study. In relation to this, a reliable method to estimate air temperatures at high-elevation sites is to apply the altitudinal temperature lapse rates (ATLR). The aims of this work are to quantify the values and the variability of the hourly ATLR and to apply this to estimated temperatures at high-elevation sites for rockfalls studies. To calculate ATLR prior the rockfalls, we used data acquired from two automatic weather stations that are located at an elevation above 2500 m. The sensors/instruments of these two stations are reliable because subjected to an accurate control and calibration once for year and the raw data have passed two automatic quality controls. Our study has yielded the following main results: (i) hourly ATLR increases slightly with increasing altitude, (ii) it is possible to estimate temperature at high-elevation sites with a good level of accuracy using ATLR, and (iii) temperature plays an important role on slope failures that occur at high-elevation sites and its importance is much more evident if the values oscillate around 0 °C with an amplitude of ±5 °C during the previous time-period. For these studies, it is not enough to improve the knowledge on air temperature, but it is necessary to develop an integrated knowledge of the thermal conditions of different materials involved in these processes (rock, debris, ice, water). Moreover, this integrated knowledge must be acquired by means of sensors and acquisition chains with known metrological traceability and uncertainty of measurements.

A zero-power warming chamber for investigating plant responses to rising temperature

DOE PAGES

Lewin, Keith F.; McMahon, Andrew M.; Ely, Kim S.; ...

2017-09-19

Advances in understanding and model representation of plant and ecosystem responses to rising temperature have typically required temperature manipulation of research plots, particularly when considering warming scenarios that exceed current climate envelopes. In remote or logistically challenging locations, passive warming using solar radiation is often the only viable approach for temperature manipulation. But, current passive warming approaches are only able to elevate the mean daily air temperature by ~1.5 °C. Motivated by our need to understand temperature acclimation in the Arctic, where warming has been markedly greater than the global average and where future warming is projected to be ~2–3more » °C by the middle of the century; we have developed an alternative approach to passive warming. Our zero-power warming (ZPW) chamber requires no electrical power for fully autonomous operation. It uses a novel system of internal and external heat exchangers that allow differential actuation of pistons in coupled cylinders to control chamber venting. This enables the ZPW chamber venting to respond to the difference between the external and internal air temperatures, thereby increasing the potential for warming and eliminating the risk of overheating. During the thaw season on the coastal tundra of northern Alaska our ZPW chamber was able to elevate the mean daily air temperature 2.6 °C above ambient, double the warming achieved by an adjacent passively warmed control chamber that lacked our hydraulic system. We describe the construction, evaluation and performance of our ZPW chamber and discuss the impact of potential artefacts associated with the design and its operation on the Arctic tundra. Our approach is highly flexible and tunable, enabling customization for use in many different environments where significantly greater temperature manipulation than that possible with existing passive warming approaches is desired.« less

A zero-power warming chamber for investigating plant responses to rising temperature

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

Lewin, Keith F.; McMahon, Andrew M.; Ely, Kim S.

Advances in understanding and model representation of plant and ecosystem responses to rising temperature have typically required temperature manipulation of research plots, particularly when considering warming scenarios that exceed current climate envelopes. In remote or logistically challenging locations, passive warming using solar radiation is often the only viable approach for temperature manipulation. But, current passive warming approaches are only able to elevate the mean daily air temperature by ~1.5 °C. Motivated by our need to understand temperature acclimation in the Arctic, where warming has been markedly greater than the global average and where future warming is projected to be ~2–3more » °C by the middle of the century; we have developed an alternative approach to passive warming. Our zero-power warming (ZPW) chamber requires no electrical power for fully autonomous operation. It uses a novel system of internal and external heat exchangers that allow differential actuation of pistons in coupled cylinders to control chamber venting. This enables the ZPW chamber venting to respond to the difference between the external and internal air temperatures, thereby increasing the potential for warming and eliminating the risk of overheating. During the thaw season on the coastal tundra of northern Alaska our ZPW chamber was able to elevate the mean daily air temperature 2.6 °C above ambient, double the warming achieved by an adjacent passively warmed control chamber that lacked our hydraulic system. We describe the construction, evaluation and performance of our ZPW chamber and discuss the impact of potential artefacts associated with the design and its operation on the Arctic tundra. Our approach is highly flexible and tunable, enabling customization for use in many different environments where significantly greater temperature manipulation than that possible with existing passive warming approaches is desired.« less

A zero-power warming chamber for investigating plant responses to rising temperature

NASA Astrophysics Data System (ADS)

Lewin, Keith F.; McMahon, Andrew M.; Ely, Kim S.; Serbin, Shawn P.; Rogers, Alistair

2017-09-01

Advances in understanding and model representation of plant and ecosystem responses to rising temperature have typically required temperature manipulation of research plots, particularly when considering warming scenarios that exceed current climate envelopes. In remote or logistically challenging locations, passive warming using solar radiation is often the only viable approach for temperature manipulation. However, current passive warming approaches are only able to elevate the mean daily air temperature by ˜ 1.5 °C. Motivated by our need to understand temperature acclimation in the Arctic, where warming has been markedly greater than the global average and where future warming is projected to be ˜ 2-3 °C by the middle of the century; we have developed an alternative approach to passive warming. Our zero-power warming (ZPW) chamber requires no electrical power for fully autonomous operation. It uses a novel system of internal and external heat exchangers that allow differential actuation of pistons in coupled cylinders to control chamber venting. This enables the ZPW chamber venting to respond to the difference between the external and internal air temperatures, thereby increasing the potential for warming and eliminating the risk of overheating. During the thaw season on the coastal tundra of northern Alaska our ZPW chamber was able to elevate the mean daily air temperature 2.6 °C above ambient, double the warming achieved by an adjacent passively warmed control chamber that lacked our hydraulic system. We describe the construction, evaluation and performance of our ZPW chamber and discuss the impact of potential artefacts associated with the design and its operation on the Arctic tundra. The approach we describe is highly flexible and tunable, enabling customization for use in many different environments where significantly greater temperature manipulation than that possible with existing passive warming approaches is desired.

Live performance of male broilers subjected to constant or increasing air velocities at moderate temperatures with a high dew point.

PubMed

Dozier, W A; Lott, B D; Branton, S L

2005-08-01

This study examined the effects of varying air velocities vs. a constant air velocity with a cyclic temperature curve of 25-30-25 degrees C and a dew point of 23 degrees C on broilers from 28 to 49 d of age. Four replicate trials were conducted. In each trial, 742 male broilers were randomly allocated to 6 floor pens or 2 air velocity tunnels, with each tunnel consisting of 4 pens. Bird density, feeder, and waterer space were similar across all pens (53 birds/ pen; 0.07 m2/bird). The treatments were control (still air), constant air velocity of 120 m/min, and increasing air velocity (90 m/min from 28 to 35 d, 120 m/min from 36 to 42 d, and 180 m/min from 43 to 49 d). Birds grown in a still air environment gained less weight, consumed less feed, and converted feed less efficiently between 28 and 49 d than birds subjected to moving air (constant or increasing). Growth responses between the air velocity treatments were similar from 28 to 35 and 36 to 42 d of age. Increasing air velocity to 180 m/min improved (P < or = 0.02) the growth rate of broilers from 43 to 49 d of age over birds receiving an air velocity of 120 m/min, but the incidence of mortality was not affected. These results provide evidence that increasing air velocity from 120 to 180 m/min is beneficial to broilers weighing 2.5 kg or greater when exposed to moderate temperatures.

Forced-air patient warming blankets disrupt unidirectional airflow.

PubMed

Legg, A J; Hamer, A J

2013-03-01

We have recently shown that waste heat from forced-air warming blankets can increase the temperature and concentration of airborne particles over the surgical site. The mechanism for the increased concentration of particles and their site of origin remained unclear. We therefore attempted to visualise the airflow in theatre over a simulated total knee replacement using neutral-buoyancy helium bubbles. Particles were created using a Rocket PS23 smoke machine positioned below the operating table, a potential area of contamination. The same theatre set-up, warming devices and controls were used as in our previous study. This demonstrated that waste heat from the poorly insulated forced-air warming blanket increased the air temperature on the surgical side of the drape by > 5°C. This created convection currents that rose against the downward unidirectional airflow, causing turbulence over the patient. The convection currents increased the particle concentration 1000-fold (2 174 000 particles/m(3) for forced-air warming vs 1000 particles/m(3) for radiant warming and 2000 particles/m(3) for the control) by drawing potentially contaminated particles from below the operating table into the surgical site. Cite this article: Bone Joint J 2013;95-B:407-10.

Impact of control for air pollution and respiratory epidemics on the estimated associations of temperature and daily mortality.

PubMed

O'Neill, Marie S; Hajat, Shakoor; Zanobetti, Antonella; Ramirez-Aguilar, Matiana; Schwartz, Joel

2005-11-01

We assessed the influence of control for air pollution and respiratory epidemics on associations between apparent temperature (AT) and daily mortality in Mexico City and Monterrey. Poisson regressions were fit to mortality among all ages, children (ages 0-14 years) and the elderly (ages >or=65 years). Predictors included mean daily AT, season, day of week and public holidays for the base model. Respiratory epidemics and air pollution (particulate matter <10 microm in aerodynamic diameter and O3) were added singly and then jointly for a fully adjusted model. Percent changes in mortality were calculated for days of relatively extreme temperatures [cold (10-11 degrees C) for both cities and heat (35-36 degrees C) for Monterrey], compared to days at the overall mean temperature in each city (15 degrees C in Mexico City, 25 degrees C in Monterrey). In Mexico City, total mortality increased 12.4% [95% confidence interval (CI) 10.5%, 14.5%] on cold days (fully adjusted). Among children, the adjusted association was similar [10.9% (95% CI: 5.4%, 16.7%)], but without control for pollution and epidemics, was nearly twice as large [19.7% (95% CI: 13.9%, 25.9)]. In Monterrey, the fully adjusted heat effect for all deaths was 18.7% (95% CI: 11.7%, 26.1%), a third lower than the unadjusted estimate; the heat effect was lower among children [5.5% (95% CI: -10.1%, 23.8%)]. Cold had a similar effect on all-age mortality as in Mexico City [11.7% (95% CI: 3.7%, 20.3%)]. Responses of the elderly differed little from all-ages responses in both cities. Associations between weather and health persisted even with control for air pollution and respiratory epidemics in two Mexican cities, but risk assessments and climate change adaptation programs are best informed by analyses that account for these potential confounders.

Impact of control for air pollution and respiratory epidemics on the estimated associations of temperature and daily mortality

NASA Astrophysics Data System (ADS)

O'Neill, Marie S.; Hajat, Shakoor; Zanobetti, Antonella; Ramirez-Aguilar, Matiana; Schwartz, Joel

2005-11-01

We assessed the influence of control for air pollution and respiratory epidemics on associations between apparent temperature (AT) and daily mortality in Mexico City and Monterrey. Poisson regressions were fit to mortality among all ages, children (ages 0 14 years) and the elderly (ages ≥65 years). Predictors included mean daily AT, season, day of week and public holidays for the base model. Respiratory epidemics and air pollution (particulate matter <10 μm in aerodynamic diameter and O3) were added singly and then jointly for a fully adjusted model. Percent changes in mortality were calculated for days of relatively extreme temperatures [cold (10 11°C) for both cities and heat (35 36°C) for Monterrey], compared to days at the overall mean temperature in each city (15°C in Mexico City, 25°C in Monterrey). In Mexico City, total mortality increased 12.4% [95% confidence interval (CI) 10.5%, 14.5%] on cold days (fully adjusted). Among children, the adjusted association was similar [10.9% (95% CI: 5.4%, 16.7%)], but without control for pollution and epidemics, was nearly twice as large [19.7% (95% CI: 13.9%, 25.9)]. In Monterrey, the fully adjusted heat effect for all deaths was 18.7% (95% CI: 11.7%, 26.1%), a third lower than the unadjusted estimate; the heat effect was lower among children [5.5% (95% CI: -10.1%, 23.8%)]. Cold had a similar effect on all-age mortality as in Mexico City [11.7% (95% CI: 3.7%, 20.3%)]. Responses of the elderly differed little from all-ages responses in both cities. Associations between weather and health persisted even with control for air pollution and respiratory epidemics in two Mexican cities, but risk assessments and climate change adaptation programs are best informed by analyses that account for these potential confounders.

Soil and air temperatures for different habitats in Mount Rainier National Park.

Treesearch

Sarah E. Greene; Mark Klopsch

1985-01-01

This paper reports air and soil temperature data from 10 sites in Mount Rainier National Park in Washington State for 2- to 5-year periods. Data provided are monthly summaries for day and night mean air temperatures, mean minimum and maximum air temperatures, absolute minimum and maximum air temperatures, range of air temperatures, mean soil temperature, and absolute...

Photosynthesis and Transpiration of Monterey Pine Seedlings as a Function of Soil Water Suction and Soil Temperature

PubMed Central

Babalola, O.; Boersma, L.; Youngberg, C. T.

1968-01-01

Rates of photosynthesis, respiration, and transpiration of Monterey pine (Pinus radiata D. Don) were measured under controlled conditions of soil water suction and soil temperature. Air temperature, relative humidity, light intensity, and air movement were maintained constant. Rates of net photosynthesis, respiration, and transpiration decreased with increasing soil water suction. The decrease in the rates of net photosynthesis and transpiration as a function of the soil temperature at low soil water suctions may be attributed to changes in the viscosity of water. At soil water suctions larger than 0.70 bars rates of transpiration and net photosynthesis may be affected in the same proportion by changes in stomatal apertures. Images PMID:16656800

Experimental investigation on the thermal performance of heat storage walls coupled with active solar systems

NASA Astrophysics Data System (ADS)

Zhao, Chunyu; You, Shijun; Zhu, Chunying; Yu, Wei

2016-12-01

This paper presents an experimental investigation of the performance of a system combining a low-temperature water wall radiant heating system and phase change energy storage technology with an active solar system. This system uses a thermal storage wall that is designed with multilayer thermal storage plates. The heat storage material is expanded graphite that absorbs a mixture of capric acid and lauric acid. An experiment is performed to study the actual effect. The following are studied under winter conditions: (1) the temperature of the radiation wall surface, (2) the melting status of the thermal storage material in the internal plate, (3) the density of the heat flux, and (4) the temperature distribution of the indoor space. The results reveal that the room temperature is controlled between 16 and 20 °C, and the thermal storage wall meets the heating and temperature requirements. The following are also studied under summer conditions: (1) the internal relationship between the indoor temperature distribution and the heat transfer within the regenerative plates during the day and (2) the relationship between the outlet air temperature and inlet air temperature in the thermal storage wall in cooling mode at night. The results indicate that the indoor temperature is approximately 27 °C, which satisfies the summer air-conditioning requirements.

Daniel K. Inouye Solar Telescope: computational fluid dynamic analyses and evaluation of the air knife model

NASA Astrophysics Data System (ADS)

McQuillen, Isaac; Phelps, LeEllen; Warner, Mark; Hubbard, Robert

2016-08-01

Implementation of an air curtain at the thermal boundary between conditioned and ambient spaces allows for observation over wavelength ranges not practical when using optical glass as a window. The air knife model of the Daniel K. Inouye Solar Telescope (DKIST) project, a 4-meter solar observatory that will be built on Haleakalā, Hawai'i, deploys such an air curtain while also supplying ventilation through the ceiling of the coudé laboratory. The findings of computational fluid dynamics (CFD) analysis and subsequent changes to the air knife model are presented. Major design constraints include adherence to the Interface Control Document (ICD), separation of ambient and conditioned air, unidirectional outflow into the coudé laboratory, integration of a deployable glass window, and maintenance and accessibility requirements. Optimized design of the air knife successfully holds full 12 Pa backpressure under temperature gradients of up to 20°C while maintaining unidirectional outflow. This is a significant improvement upon the .25 Pa pressure differential that the initial configuration, tested by Linden and Phelps, indicated the curtain could hold. CFD post- processing, developed by Vogiatzis, is validated against interferometry results of initial air knife seeing evaluation, performed by Hubbard and Schoening. This is done by developing a CFD simulation of the initial experiment and using Vogiatzis' method to calculate error introduced along the optical path. Seeing error, for both temperature differentials tested in the initial experiment, match well with seeing results obtained from the CFD analysis and thus validate the post-processing model. Application of this model to the realizable air knife assembly yields seeing errors that are well within the error budget under which the air knife interface falls, even with a temperature differential of 20°C between laboratory and ambient spaces. With ambient temperature set to 0°C and conditioned temperature set to 20°C, representing the worst-case temperature gradient, the spatial rms wavefront error in units of wavelength is 0.178 (88.69 nm at λ = 500 nm).

Comparison of microclimate in various land-use systems in Sumatra, Indonesia

NASA Astrophysics Data System (ADS)

Shekhar Badu, Chandra; Meijide, Ana; Gunawan, Dodo; Knohl, Alexander

2017-04-01

Deforestation and land-use changes are ongoing problems for rain forests in Indonesia. The conversion of forests to monocultures of rubber and oil palm plantations reduces not only biodiversity and carbon pools but also affects canopy structure, which is an important determinant of microclimate. There is, however, a lack of quantitative information characterizing the effect of land transformation on microclimate with a systematic experimental design. Here, we report observations microclimatic conditions (air temperature, relative humidity, soil moisture and soil temperature) on a daily, weekly and seasonal basis across four land-use systems (rain forest, jungle rubber, rubber plantation, oil palm plantation) in two near-by landscapes. The data set covers a period of approximately three years from April 2013 to March 2016 and includes one of the strongest El Nino-Southern Oscillation (ENSO) of the last decades. Mean air temperature, soil temperature, relative humidity, and vapour pressure deficit differed significantly between the four land-use systems whereas the mean soil moisture differed significantly between two landscapes. Air temperature, vapour pressure deficit and soil temperature were highest in oil palm and rubber plantations whereas lowest in forest and jungle rubber. Canopy openness was the most dominant control of microclimatic differences across the land-use systems. During the ENSO 2015, a significant increase in mean air temperature, soil temperature and vapour pressure deficit but a decrease in relative air humidity and soil moisture in all four land-use systems was found. The relative effect of ENSO was highest in forest and jungle rubber compared to rubber and oil palm plantations. In conclusion, conversion of forest to rubber and oil palm plantations has led to substantially warmer and drier microclimatic conditions than before.

Hot-salt stress-corrosion of titanium alloys as related to turbine operation

NASA Technical Reports Server (NTRS)

Gray, H. R.

1972-01-01

In an effort to simulate typical compressor operating conditions of current turbine engines, special test facilities were designed. Air velocity, air pressure, air dewpoint, salt deposition temperature, salt concentration, and specimen surface condition were systematically controlled and their influence on hot-salt stress-corrosion evaluated. The influence of both continuous and cyclic stress-temperature exposures was determined. The relative susceptibility of a variety of titanium alloys in commonly used heat-treated conditions was determined. The effects of both environmental and material variables were used to interpret the behavior of titanium alloys under hot-salt stress-corrosion conditions found in jet engines and to appraise their future potential under such conditions.

Pure rotational CARS thermometry studies of low-temperature oxidation kinetics in air and ethene-air nanosecond pulse discharge plasmas

NASA Astrophysics Data System (ADS)

Zuzeek, Yvette; Choi, Inchul; Uddi, Mruthunjaya; Adamovich, Igor V.; Lempert, Walter R.

2010-03-01

Pure rotational CARS thermometry is used to study low-temperature plasma assisted fuel oxidation kinetics in a repetitive nanosecond pulse discharge in ethene-air at stoichiometric and fuel lean conditions at 40 Torr pressure. Air and fuel-air mixtures are excited by a burst of high-voltage nanosecond pulses (peak voltage, 20 kV; pulse duration, ~ 25 ns) at a 40 kHz pulse repetition rate and a burst repetition rate of 10 Hz. The number of pulses in the burst is varied from a few pulses to a few hundred pulses. The results are compared with the previously developed hydrocarbon-air plasma chemistry model, modified to incorporate non-empirical scaling of the nanosecond discharge pulse energy coupled to the plasma with number density, as well as one-dimensional conduction heat transfer. Experimental time-resolved temperature, determined as a function of the number of pulses in the burst, is found to agree well with the model predictions. The results demonstrate that the heating rate in fuel-air plasmas is much faster compared with air plasmas, primarily due to energy release in exothermic reactions of fuel with O atoms generated by the plasma. It is found that the initial heating rate in fuel-air plasmas is controlled by the rate of radical (primarily O atoms) generation and is nearly independent of the equivalence ratio. At long burst durations, the heating rate in lean fuel air-mixtures is significantly reduced when all fuel is oxidized.

40 CFR Appendix A to Subpart D of... - Tables

Code of Federal Regulations, 2011 CFR

2011-07-01

... post-test values) kPa Ra Relative humidity of the ambient air percent T Absolute temperature at air...) CONTROL OF EMISSIONS FROM NONROAD SPARK-IGNITION ENGINES AT OR BELOW 19 KILOWATTS Emission Test Equipment... torque related to maximum torque for the test mode percent mass Pollutant mass flow g/h nd, i Engine...

40 CFR Appendix A to Subpart D of... - Tables

Code of Federal Regulations, 2013 CFR

2013-07-01

... post-test values) kPa Ra Relative humidity of the ambient air percent T Absolute temperature at air...) CONTROL OF EMISSIONS FROM NONROAD SPARK-IGNITION ENGINES AT OR BELOW 19 KILOWATTS Emission Test Equipment... torque related to maximum torque for the test mode percent mass Pollutant mass flow g/h nd, i Engine...

40 CFR Appendix A to Subpart D of... - Tables

Code of Federal Regulations, 2010 CFR

2010-07-01

... post-test values) kPa Ra Relative humidity of the ambient air percent T Absolute temperature at air...) CONTROL OF EMISSIONS FROM NONROAD SPARK-IGNITION ENGINES AT OR BELOW 19 KILOWATTS Emission Test Equipment... torque related to maximum torque for the test mode percent mass Pollutant mass flow g/h nd, i Engine...

40 CFR Appendix A to Subpart D of... - Tables

Code of Federal Regulations, 2012 CFR

2012-07-01

... post-test values) kPa Ra Relative humidity of the ambient air percent T Absolute temperature at air...) CONTROL OF EMISSIONS FROM NONROAD SPARK-IGNITION ENGINES AT OR BELOW 19 KILOWATTS Emission Test Equipment... torque related to maximum torque for the test mode percent mass Pollutant mass flow g/h nd, i Engine...

40 CFR Appendix A to Subpart D of... - Tables

Code of Federal Regulations, 2014 CFR

2014-07-01

... post-test values) kPa Ra Relative humidity of the ambient air percent T Absolute temperature at air...) CONTROL OF EMISSIONS FROM NONROAD SPARK-IGNITION ENGINES AT OR BELOW 19 KILOWATTS Emission Test Equipment... torque related to maximum torque for the test mode percent mass Pollutant mass flow g/h nd, i Engine...

Magnetic Properties and Moessbauer Spectra of Several Iron(III) Dicarboxylic Acid Complexes.

DTIC Science & Technology

1980-10-01

model CS-202 Displex Cryogenic refrigerator with a model APD-E temperature controller manufactured by Air Products and Chemicals , Inc ., Allentown, Pa...coupled tL a special, helium gas filled shroud, Model DMX-20, supplied by Air Products and Chemicals , Inc . Infrared spectra were obtained on a Beckman IR

THE DISTRIBUTION OF CHLORPYRIFOS FOLLOWING A CRACK AND CREVICE TYPE APPLICAITON IN THE U.S. EPA INDOOR AIR QUALITY (IAQ) TEST HOUSE

EPA Science Inventory

Pesticides found in homes may result from indoor applications to control household pests or by translocation from outdoor sources. Pesticides disperse according to their physical properties and other factors such as human activity, residential air exchange, temperature and humi...

THE SPATIAL AND TEMPORAL DISTRIBUTION OF CHLORPYRIFOS IN THE U.S. EPA INDOOR AIR QUALITY (IAQ) TEST HOUSE FOLLOWING CRACK AND CREVICE TYPE APPLICATIONS

EPA Science Inventory

Pesticides found in homes may result from indoor applications to control household pests or by translocation from outdoor sources. Pesticides disperse according to their physical properties and other factors such as human activity, air exchange, temperature and humidity. Insect...

40 CFR 1065.120 - Fuel properties and fuel temperature and pressure.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 33 2011-07-01 2011-07-01 false Fuel properties and fuel temperature and pressure. 1065.120 Section 1065.120 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Equipment Specifications § 1065.120 Fuel...

40 CFR 1065.120 - Fuel properties and fuel temperature and pressure.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 34 2012-07-01 2012-07-01 false Fuel properties and fuel temperature and pressure. 1065.120 Section 1065.120 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Equipment Specifications § 1065.120 Fuel...

40 CFR 1065.120 - Fuel properties and fuel temperature and pressure.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Fuel properties and fuel temperature and pressure. 1065.120 Section 1065.120 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Equipment Specifications § 1065.120 Fuel...

40 CFR 1065.120 - Fuel properties and fuel temperature and pressure.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 33 2014-07-01 2014-07-01 false Fuel properties and fuel temperature and pressure. 1065.120 Section 1065.120 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Equipment Specifications § 1065.120 Fuel...

40 CFR 1065.120 - Fuel properties and fuel temperature and pressure.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 34 2013-07-01 2013-07-01 false Fuel properties and fuel temperature and pressure. 1065.120 Section 1065.120 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Equipment Specifications § 1065.120 Fuel...

Quality Control for Ambient Sampling of PCDD/PCDF from Open Combustion Sources

EPA Science Inventory

Both long duration (> 6 h) and high temperature (up to 139o C) sampling efforts were conducted using ambient air sampling methods to determine if either high volume throughput or higher than ambient sampling temperatures resulted in loss of target polychlorinated dibenzodioxins/d...

A lightweight ambient air-cooling unit for use in hazardous environments.

PubMed

Chen, Y T; Constable, S H; Bomalaski, S H

1997-01-01

Recent research demonstrated (a) the effectiveness of intermittent conditioned air cooling during rest breaks to significantly reduce cumulative heat storage and (b) that longer work sessions were possible for individuals wearing chemical defense ensembles. To further advance this concept, a strategy for implementing continuous air cooling was conceived; ambient air cooling was added during work cycles and conditioned air cooling was delivered during rest periods. A compact battery-powered beltpack cooling unit (3.9 kg) designed and made at the U.S. Air Force Armstrong Laboratory was used to deliver 5.7 L/sec filtered ambient air during work cycles: 4.7 L/sec to the body and 1 L/sec to the face. Five experimental cycles were conducted in a thermally controlled chamber under warm conditions (32 degrees C, 40% relative humidity) with (1) no cooling-intermittent work, (2) intermittent cooling, (3) continuous cooling during intermittent exercise, and (4) no cooling-continuous work and (5) ambient air cooling during continuous exercise. Intermittent, conditioned, and continuous air cooling resulted in significant reductions in rectal temperature, mean skin temperature, and heart rate as compared with the no-cooling trials. The continuous air-cooling trial significantly improved thermal comfort and sweat evaporation. Results suggest that ambient air delivered during work cycles by a lightweight portable unit (in conjunction with conditioned air delivered during rest periods), can definitely improve personal comfort, reduce skin temperature, and decrease the cumulative fatigue common to repeated work/rest cycles in selected military and industrial applications in which individuals work in chemical defense ensembles.

Heat exchange studies on coconut oil cells as thermal energy storage for room thermal conditioning

NASA Astrophysics Data System (ADS)

Sutjahja, I. M.; Putri, Widya A.; Fahmi, Z.; Wonorahardjo, S.; Kurnia, D.

2017-07-01

As reported by many thermal environment experts, room air conditioning might be controlled by thermal mass system. In this paper we discuss the performance of coconut oil cells as room thermal energy storage. The heat exchange mechanism of coconut oil (CO) which is one of potential organic Phase Change Material (PCM) is studied based on the results of temperature measurements in the perimeter and core parts of cells. We found that the heat exchange performance, i.e. heat absorption and heat release processes of CO cells are dominated by heat conduction in the sensible solid from the higher temperature perimeter part to the lower temperature core part and heat convection during the solid-liquid phase transition and sensible liquid phase. The capability of heat absorption as measured by the reduction of air temperature is not influenced by CO cell size. Besides that, the application of CO as the thermal mass has to be accompanied by air circulation to get the cool sensation of the room’s occupants.

Compliant Metal Enhanced Convection Cooled Reverse-Flow Annular Combustor

NASA Technical Reports Server (NTRS)

Paskin, Marc D.; Acosta, Waldo A.

1994-01-01

A joint Army/NASA program was conducted to design, fabricate, and test an advanced, reverse-flow, small gas turbine combustor using a compliant metal enhanced (CME) convection wall cooling concept. The objectives of this effort were to develop a design method (basic design data base and analysis) for the CME cooling technique and tben demonstrate its application to an advanced cycle, small, reverse-flow combustor with 3000 F (1922 K) burner outlet temperature (BOT). The CME concept offers significant improvements in wall cooling effectiveness resulting in a large reduction in cooling air requirements. Therefore, more air is available for control of burner outlet temperature pattern in addition to the benefit of improved efficiency, reduced emissions, and smoke levels. Rig test results demonstrated the benefits and viability of the CME concept meeting or exceeding the aerothermal performance and liner wall temperature characteristics of similar lower temperature-rise combustors, achieving 0.15 pattern factor at 3000 F (1922 K) BOT, while utilizing approximately 80 percent less cooling air than conventional, film-cooled combustion systems.

Operational Characteristics of an Ultra Compact Combustor

DTIC Science & Technology

2014-03-27

to control this temperature profile to the turbine. A thermally non -uniform flow can create problems with power extraction and heat loading within...NOx) in an experimental rig set-up using air jet cross flows in non -reacting and reacting conditions at high pressure. NOx formation has become the...performance. One of the obstacles for implementing an UCC is the ability to control this temperature profile to the turbine. A thermally non

Cooperation of Horizontal Ground Heat Exchanger with the Ventilation Unit During Summer - Case Study

NASA Astrophysics Data System (ADS)

Romańska-Zapała, Anna; Furtak, Marcin; Dechnik, Mirosław

2017-10-01

Renewable energy sources are used in the modern energy-efficient buildings to improve their energy balance. One of them is used in the mechanical ventilation system ground air heat exchanger (earth-air heat exchanger - EAHX). This solution, right after heat recovery from exhaust air (recuperation), allows the reduction in the energy needed to obtain the desired temperature of supply air. The article presents the results of "in situ" measurements of pipe ground air heat exchanger cooperating with the air handling unit, supporting cooling the building in the summer season, in Polish climatic conditions. The laboratory consists of a ventilation unit intake - exhaust with rotor for which the source of fresh air is the air intake wall and two air intakes field cooperating with the tube with ground air heat exchangers. Selection of the source of fresh air is performed using sprocket with actuators. This system is part of the ventilation system of the Malopolska Laboratory of Energy-Efficient Building (MLBE) building of Cracow University of Technology. The measuring system are, among others, the sensors of parameters of air inlets and outlets of the heat exchanger channels EAHX and weather station that senses the local weather conditions. The measurement data are recorded and archived by the integrated process control system in the building of MLBE. During the study measurements of operating parameters of the ventilation unit cooperating with the selected source of fresh air were performed. Two cases of operation of the system: using EAHX heat exchanger and without it, were analyzed. Potentially the use of ground air heat exchanger in the mechanical ventilation system can reduce the energy demand for heating or cooling rooms by the pre-adjustment of the supply air temperature. Considering the results can be concluded that the continuous use of these exchangers is not optimal. This relationship is appropriate not only on an annual basis for the transitional periods (spring and autumn), but also in individual days in the potentially most favorable periods of work exchanger (summer and winter). Inappropriate operation of the heat exchanger, will lead to a temporary increase in energy consumption for the preparation of the desired air temperature, relative to the fresh air unit which is non-pretreated. For optimal energy system operation: exchanger EAHX - air handling unit, to preserve the most favourable parameters of inlet air to handling unit, there is a need to dynamically adjust the source of fresh air, depending on changing external conditions and the required outlet temperature of central unit (temperature of air forced to the rooms).

Effects of growth temperature and carbon dioxide enrichment on soybean seed components at different stages of development

USDA-ARS?s Scientific Manuscript database

Soybean plants were grown to maturity in controlled environment chambers and at the onset of flowering three temperature treatments were imposed that provided optimum [28/24°C], low [22/18°C] or high [36/32°C] chamber air temperatures. In addition, plants were treated continuously with either 400 o...

Cost-effective retrofit technology for reducing peak power demand in small and medium commercial buildings

DOE PAGES

Nutaro, James J.; Fugate, David L.; Kuruganti, Teja; ...

2015-05-27

We describe a cost-effective retrofit technology that uses collective control of multiple rooftop air conditioning units to reduce the peak power consumption of small and medium commercial buildings. The proposed control uses a model of the building and air conditioning units to select an operating schedule for the air conditioning units that maintains a temperature set point subject to a constraint on the number of units that may operate simultaneously. A prototype of this new control system was built and deployed in a large gymnasium to coordinate four rooftop air conditioning units. Based on data collected while operating this prototype,more » we estimate that the cost savings achieved by reducing peak power consumption is sufficient to repay the cost of the prototype within a year.« less

Integrated thermal and energy management of plug-in hybrid electric vehicles

NASA Astrophysics Data System (ADS)

Shams-Zahraei, Mojtaba; Kouzani, Abbas Z.; Kutter, Steffen; Bäker, Bernard

2012-10-01

In plug-in hybrid electric vehicles (PHEVs), the engine temperature declines due to reduced engine load and extended engine off period. It is proven that the engine efficiency and emissions depend on the engine temperature. Also, temperature influences the vehicle air-conditioner and the cabin heater loads. Particularly, while the engine is cold, the power demand of the cabin heater needs to be provided by the batteries instead of the waste heat of engine coolant. The existing energy management strategies (EMS) of PHEVs focus on the improvement of fuel efficiency based on hot engine characteristics neglecting the effect of temperature on the engine performance and the vehicle power demand. This paper presents a new EMS incorporating an engine thermal management method which derives the global optimal battery charge depletion trajectories. A dynamic programming-based algorithm is developed to enforce the charge depletion boundaries, while optimizing a fuel consumption cost function by controlling the engine power. The optimal control problem formulates the cost function based on two state variables: battery charge and engine internal temperature. Simulation results demonstrate that temperature and the cabin heater/air-conditioner power demand can significantly influence the optimal solution for the EMS, and accordingly fuel efficiency and emissions of PHEVs.

Controlling the temperature of bones using pulsed CO2 lasers: observations and mathematical modeling.

PubMed

Lévesque, Luc; Noël, Jean-Marc; Scott, Calum

2015-12-01

Temperature of porcine bone specimens are investigated by aiming a pulsed CO2 laser beam at the bone-air surface. This method of controlling temperature is believed to be flexible in medical applications as it avoids the uses of thermal devices, which are often cumbersome and generate rather larger temperature variations with time. The control of temperature using this method is modeled by the heat-conduction equation. In this investigation, it is assumed that the energy delivered by the CO2 laser is confined within a very thin surface layer of roughly 9 μm. It is shown that temperature can be maintained at a steady temperature using a CO2 laser and we demonstrate that the method can be adapted to be used in tandem with another laser beam. This method to control the temperature is believed to be useful in de-contamination of bone during the implantation treatment, in bone augmentation when using natural or synthetic materials and in low-level laser therapy.

Temperature Controller System for Gas Gun Targets

NASA Astrophysics Data System (ADS)

Bucholtz, Scott; Sheffield, Stephen

2005-07-01

A temperature controller system capable of heating and cooling gas gun targets over the range -75 C to +200 C was designed and tested. The system uses cold nitrogen gas from a liquid nitrogen Dewar for cooling and compressed air for heating. Two gas flow heaters control the gas temperature for both heating and cooling. One heater controls the temperature of the target mounting plate and the other the temperature of a copper tubing coil surrounding the target. Each heater is separately adjustable, so the target material will achieve a uniform temperature throughout its volume. A magnetic gauge with integrated thermocouples was developed to measure the internal temperature of the target. Using this system shock experiments, including equation-of-state measurements and shock initiation of high explosives, can be performed over a range of initial temperatures. Successful tests were completed on Teflon samples. This work was supported by the NNSA Enhanced Surveillance Campaign through contract DE-ACO4-01AL66850.

The study on working fluids of airborne power generation system based on Rankine cycle by heat energy

NASA Astrophysics Data System (ADS)

Guo, Yuan

2017-05-01

This paper proposed a new concept named airborne power generation system based on Rankine cycle by heat energy, namely, the presented system combined the Rankine cycle with environmental control system in aircraft to recycle the waste heat of engine bleed air with high temperature and generate power. This paper mainly discussed the choosing of optimum working fluid which could apply in the combined power generation system mentioned above when the temperature of the coming bleed air was about 400 degree centigrade.

Development of a High Temperature Heater using an Yttria Stabilized Zirconia Cored Brick Matrix

NASA Technical Reports Server (NTRS)

Smith, K. W.; Decoursin, D. G.

1971-01-01

The Ames pilot heater is a ceramic regenerative heater that provides high temperature air for aerodynamic and combustion experiments. The development of this heater to provide a heat storage bed with temperature capability of about 4600 R is described. A bed was designed and installed having cored brick elements of yttria-stabilized zirconia. The bed dimensions were 14 inches in diameter by 10 feet high. The thermal stress limitations of the bed were studied and maximum air flow rates based upon these limits were established. A combustion reheat system was designed and installed to provide the necessary control over the bed temperature distribution. The revised heater system was successfully operated at a maximum bed temperature of 4600 R. The successful operation demonstrated that yttria-stabilized zirconia cored brick can satisfy the high temperature-long duration requirement for storage heater applications.

International Space Station Common Cabin Air Assembly Water Separator On-Orbit Operation, Failure, and Redesign

NASA Technical Reports Server (NTRS)

Balistreri, Steven F., Jr.; Shaw, Laura A.; Laliberte, Yvon

2010-01-01

The ability to control the temperature and humidity of an environment or habitat is critical for human survival. These factors are important to maintaining human health and comfort, as well as maintaining mechanical and electrical equipment in good working order to support the human and to accomplish mission objectives. The temperature and humidity of the International Space Station (ISS) United States On-orbit Segment (USOS) cabin air is controlled by the Common Cabin Air Assembly (CCAA). The CCAA consists of a fan, a condensing heat exchanger (CHX), an air/water separator, temperature and liquid sensors, and electrical controlling hardware and software. The Water Separator (WS) pulls in air and water from the CHX, and centrifugally separates the mixture, sending the water to the condensate bus and the air back into the CHX outlet airstream. Two distinct early failures of the CCAA Water Separator in the Quest Airlock forced operational changes and brought about the re-design of the Water Separator to improve the useful life via modification kits. The on-orbit operational environment of the Airlock presented challenges that were not foreseen with the original design of the Water Separator. Operational changes were instituted to prolong the life of the third installed WS, while waiting for newly designed Water Separators to be delivered on-orbit. The modification kit design involved several different components of the Water Separator, including the innovative use of a fabrication technique to build the impellers used in Water Separators out of titanium instead of aluminum. The technique allowed for the cost effective production of the low quantity build. This paper will describe the failures of the Water Separators in the Quest Airlock, the operational constraints that were implemented to prolong the life of the installed Water Separators throughout the USOS, and the innovative re-design of the CCAA Water Separator.

Fiberoptics technology and its application to propulsion control systems

NASA Technical Reports Server (NTRS)

Baumbick, R. J.

1983-01-01

Current work on optical sensors and optically controlled actuators for use in air-breathing engine control systems is reviewed with particular reference to the design and operation of several new fiber-optic devices. These include a tachometer, a rotary position encoder, a Fabry-Perot interferometer and a rare-earth sensor for measuring engine gas temperatures, a high-temperature photoswitch designed for the range -55 to 260 C, and optical cables and connectors. The advantages of optics over conventional wire systems used for sensing and actuator control are briefly discussed.

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.

Time-series Analysis of Heat Waves and Emergency Department Visits in Atlanta, 1993 to 2012

PubMed Central

Chen, Tianqi; Sarnat, Stefanie E.; Grundstein, Andrew J.; Winquist, Andrea

2017-01-01

Background: Heat waves are extreme weather events that have been associated with adverse health outcomes. However, there is limited knowledge of heat waves’ impact on population morbidity, such as emergency department (ED) visits. Objectives: We investigated associations between heat waves and ED visits for 17 outcomes in Atlanta over a 20-year period, 1993–2012. Methods: Associations were estimated using Poisson log-linear models controlling for continuous air temperature, dew-point temperature, day of week, holidays, and time trends. We defined heat waves as periods of ≥2 consecutive days with temperatures beyond the 98th percentile of the temperature distribution over the period from 1945–2012. We considered six heat wave definitions using maximum, minimum, and average air temperatures and apparent temperatures. Associations by heat wave characteristics were examined. Results: Among all outcome-heat wave combinations, associations were strongest between ED visits for acute renal failure and heat waves defined by maximum apparent temperature at lag 0 [relative risk (RR) = 1.15; 95% confidence interval (CI): 1.03–1.29], ED visits for ischemic stroke and heat waves defined by minimum temperature at lag 0 (RR = 1.09; 95% CI: 1.02–1.17), and ED visits for intestinal infection and heat waves defined by average temperature at lag 1 (RR = 1.10; 95% CI: 1.00–1.21). ED visits for all internal causes were associated with heat waves defined by maximum temperature at lag 1 (RR = 1.02; 95% CI: 1.00, 1.04). Conclusions: Heat waves can confer additional risks of ED visits beyond those of daily air temperature, even in a region with high air-conditioning prevalence. https://doi.org/10.1289/EHP44 PMID:28599264

Time-series Analysis of Heat Waves and Emergency Department Visits in Atlanta, 1993 to 2012.

PubMed

Chen, Tianqi; Sarnat, Stefanie E; Grundstein, Andrew J; Winquist, Andrea; Chang, Howard H

2017-05-31

Heat waves are extreme weather events that have been associated with adverse health outcomes. However, there is limited knowledge of heat waves' impact on population morbidity, such as emergency department (ED) visits. We investigated associations between heat waves and ED visits for 17 outcomes in Atlanta over a 20-year period, 1993-2012. Associations were estimated using Poisson log-linear models controlling for continuous air temperature, dew-point temperature, day of week, holidays, and time trends. We defined heat waves as periods of consecutive days with temperatures beyond the 98th percentile of the temperature distribution over the period from 1945-2012. We considered six heat wave definitions using maximum, minimum, and average air temperatures and apparent temperatures. Associations by heat wave characteristics were examined. Among all outcome-heat wave combinations, associations were strongest between ED visits for acute renal failure and heat waves defined by maximum apparent temperature at lag 0 [relative risk (RR) = 1.15; 95% confidence interval (CI): 1.03-1.29], ED visits for ischemic stroke and heat waves defined by minimum temperature at lag 0 (RR = 1.09; 95% CI: 1.02-1.17), and ED visits for intestinal infection and heat waves defined by average temperature at lag 1 (RR = 1.10; 95% CI: 1.00-1.21). ED visits for all internal causes were associated with heat waves defined by maximum temperature at lag 1 (RR = 1.02; 95% CI: 1.00, 1.04). Heat waves can confer additional risks of ED visits beyond those of daily air temperature, even in a region with high air-conditioning prevalence. https://doi.org/10.1289/EHP44.

Cold temperature effects on speciated MSAT emissions from light duty vehicles operating on gasoline and ethanol blends

EPA Science Inventory

Emissions of speciated volatile organic compounds (VOCs), including mobile source air toxics (MSATs), were measured in vehicle exhaust from three light-duty gasoline vehicles. Vehicle testing was conducted using a three phase LA92 driving cycle on a temperature controlled chassis...

Microclimatic Performance of a Free-Air Warming and CO2 Enrichment Experiment in Windy Wyoming, USA

PubMed Central

LeCain, Daniel; Smith, David; Morgan, Jack; Kimball, Bruce A.; Pendall, Elise; Miglietta, Franco

2015-01-01

In order to plan for global changing climate experiments are being conducted in many countries, but few have monitored the effects of the climate change treatments (warming, elevated CO2) on the experimental plot microclimate. During three years of an eight year study with year-round feedback-controlled infra-red heater warming (1.5/3.0°C day/night) and growing season free-air CO2 enrichment (600 ppm) in the mixed-grass prairie of Wyoming, USA, we monitored soil, leaf, canopy-air, above-canopy-air temperatures and relative humidity of control and treated experimental plots and evaluated ecologically important temperature differentials. Leaves were warmed somewhat less than the target settings (1.1 & 1.5°C day/night) but soil was warmed more creating an average that matched the target settings extremely well both during the day and night plus the summer and winter. The site typically has about 50% bare or litter covered soil, therefore soil heat transfer is more critical than in dense canopy ecosystems. The Wyoming site commonly has strong winds (5 ms-1 average) and significant daily and seasonal temperature fluctuations (as much as 30°C daily) but the warming system was nearly always able to maintain the set temperatures regardless of abiotic variation. The within canopy-air was only slightly warmed and above canopy-air was not warmed by the system, therefore convective warming was minor. Elevated CO2 had no direct effect nor interaction with the warming treatment on microclimate. Relative humidity within the plant canopy was only slightly reduced by warming. Soil water content was reduced by warming but increased by elevated CO2. This study demonstrates the importance of monitoring the microclimate in manipulative field global change experiments so that critical physiological and ecological conclusions can be determined. Highly variable energy demand fluctuations showed that passive IR heater warming systems will not maintain desired warming for much of the time. PMID:25658313

Microclimatic performance of a free-air warming and CO₂ enrichment experiment in windy Wyoming, USA

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

LeCain, Daniel; Smith, David; Morgan, Jack

In order to plan for global changing climate experiments are being conducted in many countries, but few have monitored the effects of the climate change treatments (warming, elevated CO₂) on the experimental plot microclimate. During three years of an eight year study with year-round feedback-controlled infra-red heater warming (1.5/3.0°C day/night) and growing season free-air CO₂ enrichment (600 ppm) in the mixed-grass prairie of Wyoming, USA, we monitored soil, leaf, canopy-air, above-canopy-air temperatures and relative humidity of control and treated experimental plots and evaluated ecologically important temperature differentials. Leaves were warmed somewhat less than the target settings (1.1 & 1.5°C day/night)more » but soil was warmed more creating an average that matched the target settings extremely well both during the day and night plus the summer and winter. The site typically has about 50% bare or litter covered soil, therefore soil heat transfer is more critical than in dense canopy ecosystems. The Wyoming site commonly has strong winds (5 ms⁻¹ average) and significant daily and seasonal temperature fluctuations (as much as 30°C daily) but the warming system was nearly always able to maintain the set temperatures regardless of abiotic variation. The within canopy-air was only slightly warmed and above canopy-air was not warmed by the system, therefore convective warming was minor. Elevated CO₂ had no direct effect nor interaction with the warming treatment on microclimate. Relative humidity within the plant canopy was only slightly reduced by warming. Soil water content was reduced by warming but increased by elevated CO₂. This study demonstrates the importance of monitoring the microclimate in manipulative field global change experiments so that critical physiological and ecological conclusions can be determined. Highly variable energy demand fluctuations showed that passive IR heater warming systems will not maintain desired warming for much of the time.« less

Microclimatic performance of a free-air warming and CO₂ enrichment experiment in windy Wyoming, USA

DOE PAGES

LeCain, Daniel; Smith, David; Morgan, Jack; ...

2015-02-06

In order to plan for global changing climate experiments are being conducted in many countries, but few have monitored the effects of the climate change treatments (warming, elevated CO₂) on the experimental plot microclimate. During three years of an eight year study with year-round feedback-controlled infra-red heater warming (1.5/3.0°C day/night) and growing season free-air CO₂ enrichment (600 ppm) in the mixed-grass prairie of Wyoming, USA, we monitored soil, leaf, canopy-air, above-canopy-air temperatures and relative humidity of control and treated experimental plots and evaluated ecologically important temperature differentials. Leaves were warmed somewhat less than the target settings (1.1 & 1.5°C day/night)more » but soil was warmed more creating an average that matched the target settings extremely well both during the day and night plus the summer and winter. The site typically has about 50% bare or litter covered soil, therefore soil heat transfer is more critical than in dense canopy ecosystems. The Wyoming site commonly has strong winds (5 ms⁻¹ average) and significant daily and seasonal temperature fluctuations (as much as 30°C daily) but the warming system was nearly always able to maintain the set temperatures regardless of abiotic variation. The within canopy-air was only slightly warmed and above canopy-air was not warmed by the system, therefore convective warming was minor. Elevated CO₂ had no direct effect nor interaction with the warming treatment on microclimate. Relative humidity within the plant canopy was only slightly reduced by warming. Soil water content was reduced by warming but increased by elevated CO₂. This study demonstrates the importance of monitoring the microclimate in manipulative field global change experiments so that critical physiological and ecological conclusions can be determined. Highly variable energy demand fluctuations showed that passive IR heater warming systems will not maintain desired warming for much of the time.« less

[Characteristics of mercury exchange flux between soil and atmosphere under the snow retention and snow melting control].

PubMed

Zhang, Gang; Wang, Ning; Ai, Jian-Chao; Zhang, Lei; Yang, Jing; Liu, Zi-Qi

2013-02-01

Jiapigou gold mine, located in the upper Songhua River, was once the largest mine in China due to gold output, where gold extraction with algamation was widely applied to extract gold resulting in severe mercury pollution to ambient environmental medium. In order to study the characteristics of mercury exchange flux between soil (snow) and atmosphere under the snow retention and snow melting control, sampling sites were selected in equal distances along the slope which is situated in the typical hill-valley terrain unit. Mercury exchange flux between soil (snow) and atmosphere was determined with the method of dynamic flux chamber and in all sampling sites the atmosphere concentration from 0 to 150 cm near to the earth in the vertical direction was measured. Furthermore, the impact factors including synchronous meteorology, the surface characteristics under the snow retention and snow melting control and the mercury concentration in vertical direction were also investigated. The results are as follows: During the period of snow retention and melting the air mercury tends to gather towards valley bottom along the slope and an obvious deposit tendency process was found from air to the earth's surface under the control of thermal inversion due to the underlying surface of cold source (snow surface). However, during the period of snow melting, mercury exchange flux between the soil and atmosphere on the surface of the earth with the snow being melted demonstrates alternative deposit and release processes. As for the earth with snow covered, the deposit level of mercury exchange flux between soil and atmosphere is lower than that during the period of snow retention. The relationship between mercury exchange flux and impact factors shows that in snow retention there is a remarkable negative linear correlation between mercury exchange flux and air mercury concentration as well as between the former and the air temperature. In addition, in snow melting mercury exchange flux is remarkably negatively linearly correlated to air mercury concentration and positively linearly correlated to air temperature. Furthermore, there is a general positive linear correlation between mercury exchange flux and soil temperature on the surface of earth after snow melting.

Contractor cuts solar gain with custom window curtain

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

Ingraham, R.

1985-04-22

A local energy services contractor, using a 210-foot motorized thermal curtain to deflect sunlight entering the windows, has reduced excessive heat gain at a racetrack clubhouse here, cutting air conditioning run-time by about 75%. Because Mobile Greyhound Park's clubhouse faces east, direct exposure to sunlight from dawn to afternoon race time, about 1 p.m., was bringing the indoor temperature to almost 100/sup 0/, according to Stan Norris, operations management for the contracting firm, Technical Energy Controls, Inc. Lowering the temperature to a comfortable level required running four Carrier Corporation air handling units, rated at a total of more than 170more » tons, for about eight hours, and annual energy bills were running at about $240,000, Norris said. With the aluminum foil-backed vinyl curtain, the air handling units need only operate two hours to bring temperatures to comfort levels.« less

Fatigue crack growth in SA508-CL2 steel in a high temperature, high purity water environment

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

Gerber, T.L.; Heald, J.D.; Kiss, E.

1974-10-01

Fatigue crack growth tests were conducted with 1 in. plate specimens of SA508-CL 2 steel in room temperature air, 550$sup 0$F air and in a 550$sup 0$F, high purity, water environment. Zero-tension load controlled tests were run at cyclic frequencies as low as 0.037 CPM. Results show that growth rates in the simulated Boiling Water Reactor (BWR) water environment are faster than growth rates observed in 550$sup 0$F air and these rates are faster than the room temperature rate. In the BWR water environment, lowering the cyclic frequency from 0.37 to 0.037 CPM caused only a slight increase in themore » fatigue crack growth rate. All growth rates measured in these tests were below the upper bound design curve presented in Section XI of the ASME Code. (auth)« less

Noncontact Measurement of Humidity and Temperature Using Airborne Ultrasound

NASA Astrophysics Data System (ADS)

Kon, Akihiko; Mizutani, Koichi; Wakatsuki, Naoto

2010-04-01

We describe a noncontact method for measuring humidity and dry-bulb temperature. Conventional humidity sensors are single-point measurement devices, so that a noncontact method for measuring the relative humidity is required. Ultrasonic temperature sensors are noncontact measurement sensors. Because water vapor in the air increases sound velocity, conventional ultrasonic temperature sensors measure virtual temperature, which is higher than dry-bulb temperature. We performed experiments using an ultrasonic delay line, an atmospheric pressure sensor, and either a thermometer or a relative humidity sensor to confirm the validity of our measurement method at relative humidities of 30, 50, 75, and 100% and at temperatures of 283.15, 293.15, 308.15, and 323.15 K. The results show that the proposed method measures relative humidity with an error rate of less than 16.4% and dry-bulb temperature with an error of less than 0.7 K. Adaptations of the measurement method for use in air-conditioning control systems are discussed.

On the importance of radiative heat exchange during nocturnal flight in birds.

PubMed

Léger, Jérôme; Larochelle, Jacques

2006-01-01

Many migratory flights take place during cloudless nights, thus under conditions where the sky temperature can commonly be 20 degrees C below local air temperature. The sky then acts as a radiative sink, leading objects exposed to it to have a lower surface temperature than unexposed ones because less infrared energy is received from the sky than from the surfaces that are isothermic to air. To investigate the significance of this effect for heat dissipation during nocturnal flight in birds, we built a wind tunnel with the facility to control wall temperature (TASK) and air temperature (TAIR) independently at air speeds (UWIN) comparable to flying speeds. We used it to measure the influence of TASK, TAIR and UWIN on plumage and skin temperatures in pigeons having to dissipate a thermal load while constrained at rest in a flight posture. Our results show that the temperature of the flight and insulation plumages exposed to a radiative sink can be accurately described by multiple regression models (r2>0.96) based only on TAIR, TASK and UWIN. Predictions based on these models indicate that while convection dominates heat loss for a plumage exposed to air moving at flight speed in a thermally uniform environment, radiation may dominate in the presence of a radiative sink comparable to a clear sky. Our data also indicate that reducing TASK to a temperature 20 degrees C below TAIR can increase the temperature difference across the exposed plumage by at least 13% and thus facilitate heat flow through the main thermal resistance to the loss of internally produced heat in birds. While extrapolation from our experimentally constrained conditions to free flight in the atmosphere is difficult, our results suggest that the sky temperature has been a neglected factor in determining the range of TAIR over which prolonged flight is possible.

Increased Air Temperature during Simulated Autumn Conditions Impairs Photosynthetic Electron Transport between Photosystem II and Photosystem I1[OA

PubMed Central

Busch, Florian; Hüner, Norman P.A.; Ensminger, Ingo

2008-01-01

Changes in temperature and daylength trigger physiological and seasonal developmental processes that enable evergreen trees of the boreal forest to withstand severe winter conditions. Climate change is expected to increase the autumn air temperature in the northern latitudes, while the natural decreasing photoperiod remains unaffected. As shown previously, an increase in autumn air temperature inhibits CO2 assimilation, with a concomitant increased capacity for zeaxanthin-independent dissipation of energy exceeding the photochemical capacity in Pinus banksiana. In this study, we tested our previous model of antenna quenching and tested a limitation in intersystem electron transport in plants exposed to elevated autumn air temperatures. Using a factorial design, we dissected the effects of temperature and photoperiod on the function as well as the stoichiometry of the major components of the photosynthetic electron transport chain in P. banksiana. Natural summer conditions (16-h photoperiod/22°C) and late autumn conditions (8-h photoperiod/7°C) were compared with a treatment of autumn photoperiod with increased air temperature (SD/HT: 8-h photoperiod/22°C) and a treatment with summer photoperiod and autumn temperature (16-h photoperiod/7°C). Exposure to SD/HT resulted in an inhibition of the effective quantum yield associated with a decreased photosystem II/photosystem I stoichiometry coupled with decreased levels of Rubisco. Our data indicate that a greater capacity to keep the primary electron donor of photosystem I (P700) oxidized in plants exposed to SD/HT compared with the summer control may be attributed to a reduced rate of electron transport from the cytochrome b6f complex to photosystem I. Photoprotection under increased autumn air temperature conditions appears to be consistent with zeaxanthin-independent antenna quenching through light-harvesting complex II aggregation and a decreased efficiency in energy transfer from the antenna to the photosystem II core. We suggest that models that predict the effect of climate change on the productivity of boreal forests must take into account the interactive effects of photoperiod and elevated temperatures. PMID:18375598

Increased air temperature during simulated autumn conditions impairs photosynthetic electron transport between photosystem II and photosystem I.

PubMed

Busch, Florian; Hüner, Norman P A; Ensminger, Ingo

2008-05-01

Changes in temperature and daylength trigger physiological and seasonal developmental processes that enable evergreen trees of the boreal forest to withstand severe winter conditions. Climate change is expected to increase the autumn air temperature in the northern latitudes, while the natural decreasing photoperiod remains unaffected. As shown previously, an increase in autumn air temperature inhibits CO2 assimilation, with a concomitant increased capacity for zeaxanthin-independent dissipation of energy exceeding the photochemical capacity in Pinus banksiana. In this study, we tested our previous model of antenna quenching and tested a limitation in intersystem electron transport in plants exposed to elevated autumn air temperatures. Using a factorial design, we dissected the effects of temperature and photoperiod on the function as well as the stoichiometry of the major components of the photosynthetic electron transport chain in P. banksiana. Natural summer conditions (16-h photoperiod/22 degrees C) and late autumn conditions (8-h photoperiod/7 degrees C) were compared with a treatment of autumn photoperiod with increased air temperature (SD/HT: 8-h photoperiod/22 degrees C) and a treatment with summer photoperiod and autumn temperature (16-h photoperiod/7 degrees C). Exposure to SD/HT resulted in an inhibition of the effective quantum yield associated with a decreased photosystem II/photosystem I stoichiometry coupled with decreased levels of Rubisco. Our data indicate that a greater capacity to keep the primary electron donor of photosystem I (P700) oxidized in plants exposed to SD/HT compared with the summer control may be attributed to a reduced rate of electron transport from the cytochrome b6f complex to photosystem I. Photoprotection under increased autumn air temperature conditions appears to be consistent with zeaxanthin-independent antenna quenching through light-harvesting complex II aggregation and a decreased efficiency in energy transfer from the antenna to the photosystem II core. We suggest that models that predict the effect of climate change on the productivity of boreal forests must take into account the interactive effects of photoperiod and elevated temperatures.

Improved Surface Parameter Retrievals using AIRS/AMSU Data

NASA Technical Reports Server (NTRS)

Susskind, Joel; Blaisdell, John

2008-01-01

The AIRS Science Team Version 5.0 retrieval algorithm became operational at the Goddard DAAC in July 2007 generating near real-time products from analysis of AIRS/AMSU sounding data. This algorithm contains many significant theoretical advances over the AIRS Science Team Version 4.0 retrieval algorithm used previously. Two very significant developments of Version 5 are: 1) the development and implementation of an improved Radiative Transfer Algorithm (RTA) which allows for accurate treatment of non-Local Thermodynamic Equilibrium (non-LTE) effects on shortwave sounding channels; and 2) the development of methodology to obtain very accurate case by case product error estimates which are in turn used for quality control. These theoretical improvements taken together enabled a new methodology to be developed which further improves soundings in partially cloudy conditions. In this methodology, longwave C02 channel observations in the spectral region 700 cm(exp -1) to 750 cm(exp -1) are used exclusively for cloud clearing purposes, while shortwave C02 channels in the spectral region 2195 cm(exp -1) 2395 cm(exp -1) are used for temperature sounding purposes. This allows for accurate temperature soundings under more difficult cloud conditions. This paper further improves on the methodology used in Version 5 to derive surface skin temperature and surface spectral emissivity from AIRS/AMSU observations. Now, following the approach used to improve tropospheric temperature profiles, surface skin temperature is also derived using only shortwave window channels. This produces improved surface parameters, both day and night, compared to what was obtained in Version 5. These in turn result in improved boundary layer temperatures and retrieved total O3 burden.

AIRS Observations of DomeC in Antarctica and Comparison with Automated Weather Stations (AWS)

NASA Technical Reports Server (NTRS)

Aumann, Hartmut H.; Gregorich, Dave; Broberg, Steve

2006-01-01

We compare the surface temperatures at Dome Concordia (DomeC) deduced from AIRS data and two Automatic Weather Stations at Concordia Station: AWS8989 , which has been in operation since December 1996, and AWS.it, for which data are available between January and November 2005. The AWS8989 readings are on average 3 K warmer than the AWS.it readings, with a warmer bias in the Antarctic summer than in the winter season. Although AIRS measures the skin brightness temperature, while the AWS reports the temperature of the air at 3 meter above the surface, the AIRS measurements agree well with the AWS.it readings for all data and separately for the summer and winter seasons, if data taken in the presence of strong surface inversions are filtered out. This can be done by deducing the vertical temperature gradient above the surface directly from the AIRS temperature sounding channels or indirectly by noting that extreme vertical gradients near the surface are unlikely if the wind speed is more than a few meters per second. Since the AIRS measurements are very well calibrated, the agreement with AWS.it is very encouraging. The warmer readings of AWS8989 are likely due to thermal contamination of the AWS8989 site by the increasing activity at Concordia Station. Data from an AWS.it quality station could be used for the evaluation of radiometric accuracy and stability of polar orbiting sounders at low temperatures. Unfortunately, data from AWS.it was available only for a limited time. The thermal contamination of the AWS8989 data makes long-term trends deduced from AWS8989 and possibly results about the rapid Antarctic warming deduced from other research stations on Antarctica suspect. AIRS is the first hyperspectral infrared sounder designed in support of weather forecasting and climate research. It was launched in May 2002 on the EOS Aqua spacecraft into a 704 km altitude polar sun-synchronous orbit. The lifetime of AIRS, estimated before launch to be at least 5 years is, based on the latest evaluation, limited by the amount of attitude control gas on the EOS Aqua spacecraft, which is expected to last through 2015.

Optical air data systems and methods

NASA Technical Reports Server (NTRS)

Spaeth, Lisa G. (Inventor); O'Brien, Martin (Inventor); Tang, Shoou-yu (Inventor); Acott, Phillip E. (Inventor); Caldwell, Loren M. (Inventor)

2011-01-01

Systems and methods for sensing air includes at least one, and in some embodiments three, transceivers for projecting the laser energy as laser radiation to the air. The transceivers are scanned or aligned along several different axes. Each transceiver receives laser energy as it is backscattered from the air. A computer processes signals from the transceivers to distinguish molecular scattered laser radiation from aerosol scattered laser radiation and determines air temperatures, wind speeds, and wind directions based on the scattered laser radiation. Applications of the system to wind power site evaluation, wind turbine control, traffic safety, general meteorological monitoring and airport safety are presented.

Safety devices for neonatal intensive care.

PubMed

Neuman, M R; Flammer, C M; O'Connor, E

1982-01-01

Three relatively simple devices for improving safety in neonatal intensive care are described. When umbilical artery catheters are used, an inexpensive pressure switch is utilized to detect abnormally low pressures associated with catheter withdrawal or excessive fluid leakage from the catheter system. A capacitive, intravenous-line air bubble detector, consisting of a section of the intravenous line as the dielectric of a capacitor, is used to alert the clinical staff when air bubbles pass between the capacitor plates. An electronic temperature controller maintains the temperature of neonatal breathing gases to avoid temperature variations which occur with presently used techniques. These are relatively simple and inexpensive devices which can be fabricated by most hospital clinical engineering services.

A review of reaction rates in high temperature air

NASA Technical Reports Server (NTRS)

Park, Chul

1989-01-01

The existing experimental data on the rate coefficients for the chemical reactions in nonequilibrium high temperature air are reviewed and collated, and a selected set of such values is recommended for use in hypersonic flow calculations. For the reactions of neutral species, the recommended values are chosen from the experimental data that existed mostly prior to 1970, and are slightly different from those used previously. For the reactions involving ions, the recommended rate coefficients are newly chosen from the experimental data obtained more recently. The reacting environment is assumed to lack thermal equilibrium, and the rate coefficients are expressed as a function of the controlling temperature, incorporating the recent multitemperature reaction concept.

Cumulative ventilation air drying potential as an indication of dry mass content in wastewater sludge in a thin-layer solar drying facility

NASA Astrophysics Data System (ADS)

Krawczyk, Piotr

2013-12-01

Controlling low-temperature drying facilities which utilise nonprepared air is quite difficult, due to very large variability of ventilation air parameters - both in daily and seasonal cycles. The paper defines the concept of cumulative drying potential of ventilation air and presents experimental evidence that there is a relation between this parameter and condition of the dried matter (sewage sludge). Knowledge on current dry mass content in the dried matter (sewage sludge) provides new possibilities for controlling such systems. Experimental data analysed in the paper was collected in early 2012 during operation of a test solar drying facility in a sewage treatment plant in Błonie near Warsaw, Poland.

The effects of drying on physical properties of bilimbi slices (Averrhoa bilimbi l.)

NASA Astrophysics Data System (ADS)

Shahari, N.; Nursabrina, M.; Suhairah, A. Zai

2015-05-01

Physical appearance analyses of fruits are used to maintain food quality throughout and at the end of processing. However, control variables have to be designed to obtained the desired food quality. In the present study, the effects of pretreatment and drying air temperatures of 50°C, 60°C and 70°C on the drying kinetics of belimbi slices were investigated using a hot-air dryer. In order to investigate and select the appropriate drying model, seven experiment based mathematical drying models were fitted to the experimental data. According to the statistical criteria (R2, SSE and RMSE), a Logarithmic model was found to be the best model to describe the drying behaviour of belimbi slices at 40°C for control; The Page/modified Page model was the best model to describe drying behaviour at 40°C, 60°C pre-treatment and 50°C for the control and the Wang and Singh model fitted well for 50°C pre-treatment and 60°C for the control. Comparison between experiment based mathematical modelling with a single phase mathematical model shows that close agreement was produced. The qualities of belimbi slices in terms of colour, texture and shrinkage with different air temperature and pre-treatment were also investigated. Higher drying temperatures gives less drying time, a lighter colour but greater product shrinkage, whilst pre-treatment can reduce product shrinkage and drying time and can also give good texture properties. The results show that pre-treatment and the drying temperature are important to improve mass and heat transfer as well as the product characteristics such as colour, shrinkage and texture.

[Impact of canopy structural characteristics on inner air temperature and relative humidity of Koelreuteria paniculata community in summer].

PubMed

Qin, Zhong; Li, Zhan-dong; Cheng, Fang-yun; Sha, Hai-feng

2015-06-01

To investigate the diurnal variation of the correlations between the cooling and humidifying effects and canopy structural characteristics of the Koelreuteria paniculata community, the measurements of air temperature, relative humidity, canopy density, leaf area index (LAI) and mean leaf angle (MLA) were performed on calm sunny summer days in the community in Beijing Olympic Forest Park, China. There were significant correlations between the canopy density, LAI and MLA, which affected the cooling and humidifying effects together. The cooling effect reached its maximum by 12:00, whereas the humidifying effect reached its peak at 10:00. Compared with the control open space site, the community appeared to lower the air temperature by 0.43 to 7.53 °C and to increase the relative humidity by 1%-22% during the daytime. However, the cooling and humidifying effects seem to be not effective during the night. The canopy density and LAI were better for determining the cooling and humidifying effects from 9:00 to 12:00. However, these effects were largely controlled only by the canopy density from 12:00 to 14:00 and were significantly correlated with the canopy density and LAI afterwards until 18:00.

NOx control techniques for the CPI

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

Lambert, D.; McGowan, T.F.

1996-06-01

After years of air pollution control innovation, the control of emissions of nitrogen oxide compounds stands out as an area where much work remains to be performed in the chemical process industries (CPI). Federal regulations, ozone non-attainment areas, acid rain provisions of the US Clean Air Act, and corporate goals for emission reductions are all motivators. Primary CPI sources are high-temperature combustion systems, including fired heaters, boilers and Kilns. Nitrogen-based processes such as nitric acid manufacture also contribute. The paper discusses the regulations which define the problem and some solutions. These include fuel switching, low-excess air burners, fluegas recirculation, stagedmore » combustion, out of service burners, and wet scrubbing of flue gas. The paper briefly discusses costs of these options.« less

Membrane humidification--a new method for humidification of respiratory gases in ventilator treatment of neonates.

PubMed Central

Hanssler, L; Tennhoff, W; Roll, C

1992-01-01

A humidifier system for neonatology that functions according to the 'membrane humidification' principle was subjected to a performance test in our laboratory. Humidification and heating of the respiratory gases took place in a module consisting of a net of hollow fibres placed inside the incubator. In 18 measurement combinations flow, respiratory gas temperature, and incubator temperature were varied. At respiratory gas temperatures within the range of 33-37 degrees C the minimum international standard for the absolute air humidity in the respiratory gas was achieved or exceeded in all measurements. No controlled clinical tests regarding the importance and long term effects of different temperatures and different humidity levels in the inspiratory air are yet available for the ventilation treatment of neonates. PMID:1444554

Characterization of Air and Ground Temperature Relationships within the CMIP5 Historical and Future Climate Simulations

NASA Astrophysics Data System (ADS)

García-García, A.; Cuesta-Valero, F. J.; Beltrami, H.; Smerdon, J. E.

2017-12-01

The relationships between air and ground surface temperatures across North America are examined in the historical and future projection simulations from 32 General Circulation Models (GCMs) included in the fifth phase of the Coupled Model Intercomparison Project (CMIP5). The covariability between surface air (2 m) and ground surface temperatures (10 cm) is affected by simulated snow cover, vegetation cover and precipitation through changes in soil moisture at the surface. At high latitudes, the differences between air and ground surface temperatures, for all CMIP5 simulations, are related to the insulating effect of snow cover and soil freezing phenomena. At low latitudes, the differences between the two temperatures, for the majority of simulations, are inversely proportional to leaf area index and precipitation, likely due to induced-changes in latent and sensible heat fluxes at the ground surface. Our results show that the transport of energy across the air-ground interface differs from observations and among GCM simulations, by amounts that depend on the components of the land-surface models that they include. The large variability among GCMs and the marked dependency of the results on the choice of the land-surface model, illustrate the need for improving the representation of processes controlling the coupling of the lower atmosphere and the land surface in GCMs as a means of reducing the variability in their representation of weather and climate phenomena, with potentially important implications for positive climate feedbacks such as permafrost and soil carbon stability.

Thermal Imaging of Forest Canopy Temperatures: Relationships with Biological and Biophysical Drivers and Ecosystem Fluxes

NASA Astrophysics Data System (ADS)

Still, C. J.; Kim, Y.; Hanson, C. V.; Law, B. E.; Kwon, H.; Schulze, M.; Pau, S.; Detto, M.

2015-12-01

Temperature is a primary environmental control on plant processes at a range of spatial and temporal scales, affecting enzymatic reactions, ecosystem biogeochemistry, and species distributions. Although most focus is on air temperature, the radiative or skin temperature of plants is more relevant. Canopy skin temperature dynamics reflect biophysical, physiological, and anatomical characteristics and interactions with environmental drivers, and can be used to examine forest responses to stresses like droughts and heat waves. Direct measurements of plant canopy temperatures using thermocouple sensors have been challenging and offer limited information. Such measurements are usually conducted over short periods of time and a limited spatial extent of the canopy. By contrast, thermal infrared (TIR) imaging allows for extensive temporal and spatial measurement of canopy temperature regimes. We present results of TIR imaging of forest canopies at a range of well-studied forest sites in the United States and Panama. These forest types include temperate rainforests, a semi­arid pine forest, and a semi­deciduous tropical forest. Canopy temperature regimes at these sites are highly variable spatially and temporally and display frequent departures from air temperature, particularly during clear sky conditions. Canopy tissue temperatures are often warmer (daytime) and colder (nighttime) than air temperature, and canopy structure seems to have a large influence on the thermal regime. Additionally, comparison of canopy temperatures to eddy covariance fluxes of carbon dioxide, water vapor, and energy reveals relationships not apparent using air temperature. Initial comparisons between our forest canopy temperatures and remotely sensed skin temperature using Landsat and MODIS data show reasonably good agreement. We conclude that temporal and spatial changes in canopy temperature and its relationship to biological and environmental factors can improve our understanding of how climate change is affecting forest function, and argue for wider deployment of thermal cameras in other ecosystems.

Temperature regulation during ultrasonic manipulation for long-term cell handling in a microfluidic chip

NASA Astrophysics Data System (ADS)

Svennebring, J.; Manneberg, O.; Wiklund, M.

2007-12-01

We demonstrate simultaneous micromanipulation and temperature regulation by the use of ultrasonic standing wave technology in a microfluidic chip. The system is based on a microfabricated silicon structure sandwiched between two glass layers, and an external ultrasonic transducer using a refractive wedge placed on top of the chip for efficient coupling of ultrasound into the microchannel. The chip is fully transparent and compatible with any kind of high-resolution optical microscopy. The temperature regulation method uses calibration data of the temperature increase due to the ultrasonic actuation for determining the temperature of the surrounding air and microscope table, controlled by a warm-air heating unit and a heatable mounting frame. The heating methods are independent of each other, resulting in a flexible choice of ultrasonic actuation voltage and flow rate for different cell and particle manipulation purposes. Our results indicate that it is possible to perform stable temperature regulation with an accuracy of the order of ±0.1 °C around any physiologically relevant temperature (e.g., 37 °C) with high temporal stability and repeatability. The purpose is to use ultrasound for long-term cell and/or particle handling in a microfluidic chip while controlling and maintaining the biocompatibility of the system.

78 FR 26251 - Approval and Promulgation of Air Quality Implementation Plans; Texas; Revisions to Control of Air...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-06

... ovens used in wet-laid non-woven fiber mat manufacturing operations when nitrogen containing resins or other additives are used. These two actions affect NOx sources operating in the Dallas Fort-Worth (DFW... include low-temperature drying ovens and curing ovens used in wet-laid, non-woven fiber mat manufacturing...

Passenger Carrying Submersibles: System Safety Analysis

DTIC Science & Technology

1989-08-01

General Provisions Subpart B Commercial Diving Operations 33 CFR NAVIGATION (As Applicable) Subchapter 0 - Pollution Part 155 Oil Pollution...and Materials: Specifications and Approvals; Subchapter S, Subdivision and Stability; and finally, 33 CFR Subchapter 0, Part 155 Oil Pollution...contamination. Air contamination could also result from inadequate air circulation, loss of temperature/humidity control, or refrigerant or oil leakage

Characterizing G-Loading, Swirl Direction, and Rayleigh Losses in an Ultra Compact Combustor

DTIC Science & Technology

2013-07-01

temperature, pressure, and emission measurements, and liquid fuel and Jet Cat control. The code layout and functionality was simple in comparison to...84 3.6.4. Cavity Air Jet Diameter Influence on g-Loading...21 Figure 15. Cavity air injection jet diameter relationship to g-loading and tangential velocity [4] 22 Figure

14 CFR 23.1305 - Powerplant instruments.

Code of Federal Regulations, 2014 CFR

2014-01-01

... with a controllable propeller. (6) For each turbocharger installation: (i) If limitations are established for either carburetor (or manifold) air inlet temperature or exhaust gas or turbocharger turbine...

14 CFR 23.1305 - Powerplant instruments.

Code of Federal Regulations, 2010 CFR

2010-01-01

... with a controllable propeller. (6) For each turbocharger installation: (i) If limitations are established for either carburetor (or manifold) air inlet temperature or exhaust gas or turbocharger turbine...

14 CFR 23.1305 - Powerplant instruments.

Code of Federal Regulations, 2012 CFR

2012-01-01

... with a controllable propeller. (6) For each turbocharger installation: (i) If limitations are established for either carburetor (or manifold) air inlet temperature or exhaust gas or turbocharger turbine...

14 CFR 23.1305 - Powerplant instruments.

Code of Federal Regulations, 2011 CFR

2011-01-01

... with a controllable propeller. (6) For each turbocharger installation: (i) If limitations are established for either carburetor (or manifold) air inlet temperature or exhaust gas or turbocharger turbine...

14 CFR 23.1305 - Powerplant instruments.

Code of Federal Regulations, 2013 CFR

2013-01-01

... with a controllable propeller. (6) For each turbocharger installation: (i) If limitations are established for either carburetor (or manifold) air inlet temperature or exhaust gas or turbocharger turbine...

Recent Theoretical Advances in Analysis of AIRS/AMSU Sounding Data

NASA Technical Reports Server (NTRS)

Susskind, Joel

2007-01-01

AIRS was launched on EOS Aqua on May 4,2002, together with AMSU-A and HSB, to form a next generation polar orbiting infrared and microwave atmospheric sounding system. This paper describes the AIRS Science Team Version 5.0 retrieval algorithm. Starting in early 2007, the Goddard DAAC will use this algorithm to analyze near real time AIRS/AMSU observations. These products are then made available to the scientific community for research purposes. The products include twice daily measurements of the Earth's three dimensional global temperature, water vapor, and ozone distribution as well as cloud cover. In addition, accurate twice daily measurements of the earth's land and ocean temperatures are derived and reported. Scientists use this important set of observations for two major applications. They provide important information for climate studies of global and regional variability and trends of different aspects of the earth's atmosphere. They also provide information for researchers to improve the skill of weather forecasting. A very important new product of the AIRS Version 5 algorithm is accurate case-by-case error estimates of the retrieved products. This heightens their utility for use in both weather and climate applications. These error estimates are also used directly for quality control of the retrieved products. Version 5 also allows for accurate quality controlled AIRS only retrievals, called "Version 5 AO retrievals" which can be used as a backup methodology if AMSU fails. Examples of the accuracy of error estimates and quality controlled retrieval products of the AIRS/AMSU Version 5 and Version 5 AO algorithms are given, and shown to be significantly better than the previously used Version 4 algorithm. Assimilation of Version 5 retrievals are also shown to significantly improve forecast skill, especially when the case-by-case error estimates are utilized in the data assimilation process.

Associations between air temperature and cardio-respiratory mortality in the urban area of Beijing, China: a time-series analysis.

PubMed

Liu, Liqun; Breitner, Susanne; Pan, Xiaochuan; Franck, Ulrich; Leitte, Arne Marian; Wiedensohler, Alfred; von Klot, Stephanie; Wichmann, H-Erich; Peters, Annette; Schneider, Alexandra

2011-05-25

Associations between air temperature and mortality have been consistently observed in Europe and the United States; however, there is a lack of studies for Asian countries. Our study investigated the association between air temperature and cardio-respiratory mortality in the urban area of Beijing, China. Death counts for cardiovascular and respiratory diseases for adult residents (≥15 years), meteorological parameters and concentrations of particulate air pollution were obtained from January 2003 to August 2005. The effects of two-day and 15-day average temperatures were estimated by Poisson regression models, controlling for time trend, relative humidity and other confounders if necessary. Effects were explored for warm (April to September) and cold periods (October to March) separately. The lagged effects of daily temperature were investigated by polynomial distributed lag (PDL) models. We observed a J-shaped exposure-response function only for 15-day average temperature and respiratory mortality in the warm period, with 21.3°C as the threshold temperature. All other exposure-response functions could be considered as linear. In the warm period, a 5°C increase of two-day average temperature was associated with a RR of 1.098 (95% confidence interval (95%CI): 1.057-1.140) for cardiovascular and 1.134 (95%CI: 1.050-1.224) for respiratory mortality; a 5°C decrease of 15-day average temperature was associated with a RR of 1.040 (95%CI: 0.990-1.093) for cardiovascular mortality. In the cold period, a 5°C increase of two-day average temperature was associated with a RR of 1.149 (95%CI: 1.078-1.224) for respiratory mortality; a 5°C decrease of 15-day average temperature was associated with a RR of 1.057 (95%CI: 1.022-1.094) for cardiovascular mortality. The effects remained robust after considering particles as additional confounders. Both increases and decreases in air temperature are associated with an increased risk of cardiovascular mortality. The effects of heat were immediate while the ones of cold became predominant with longer time lags. Increases in air temperature are also associated with an immediate increased risk of respiratory mortality.

Associations between air temperature and cardio-respiratory mortality in the urban area of Beijing, China: a time-series analysis

PubMed Central

2011-01-01

Background Associations between air temperature and mortality have been consistently observed in Europe and the United States; however, there is a lack of studies for Asian countries. Our study investigated the association between air temperature and cardio-respiratory mortality in the urban area of Beijing, China. Methods Death counts for cardiovascular and respiratory diseases for adult residents (≥15 years), meteorological parameters and concentrations of particulate air pollution were obtained from January 2003 to August 2005. The effects of two-day and 15-day average temperatures were estimated by Poisson regression models, controlling for time trend, relative humidity and other confounders if necessary. Effects were explored for warm (April to September) and cold periods (October to March) separately. The lagged effects of daily temperature were investigated by polynomial distributed lag (PDL) models. Results We observed a J-shaped exposure-response function only for 15-day average temperature and respiratory mortality in the warm period, with 21.3°C as the threshold temperature. All other exposure-response functions could be considered as linear. In the warm period, a 5°C increase of two-day average temperature was associated with a RR of 1.098 (95% confidence interval (95%CI): 1.057-1.140) for cardiovascular and 1.134 (95%CI: 1.050-1.224) for respiratory mortality; a 5°C decrease of 15-day average temperature was associated with a RR of 1.040 (95%CI: 0.990-1.093) for cardiovascular mortality. In the cold period, a 5°C increase of two-day average temperature was associated with a RR of 1.149 (95%CI: 1.078-1.224) for respiratory mortality; a 5°C decrease of 15-day average temperature was associated with a RR of 1.057 (95%CI: 1.022-1.094) for cardiovascular mortality. The effects remained robust after considering particles as additional confounders. Conclusions Both increases and decreases in air temperature are associated with an increased risk of cardiovascular mortality. The effects of heat were immediate while the ones of cold became predominant with longer time lags. Increases in air temperature are also associated with an immediate increased risk of respiratory mortality. PMID:21612647

Fatigue flaw growth and NDI evaluation for preventing through cracks in spacecraft tankage structures

NASA Technical Reports Server (NTRS)

Pettit, D. E.; Hoeppner, D. W.

1972-01-01

A program was conducted to determine the fatigue-crack propagation behavior of parent and welded 2219-T87 aluminum alloy sheet under controlled cyclic stress conditions in room temperature air and 300 F air. Specimens possessing an initial surface defect of controlled dimensions were cycled under constant load amplitude until the propagating fatigue crack penetrated the back surface of the specimen. A series of precracked specimens were prepared to determine optimum penetrant, X-ray, ultrasonic, and eddy current nondestructive inspection procedures.

Atmospheric Soundings from AIRS/AMSU in Partial Cloud Cover

NASA Technical Reports Server (NTRS)

Susskind, Joel; Atlas, Robert

2005-01-01

Simultaneous use of AIRS/AMSU-A observations allow for the determination of accurate atmospheric soundings under partial cloud cover conditions. The methodology involves the determination of the radiances AIRS would have seen if the AIRS fields of view were clear, called clear column radiances, and use of these radiances to infer the atmospheric and surface conditions giving rise to these clear column radiances. Susskind et al. demonstrate via simulation that accurate temperature soundings and clear column radiances can be derived from AIRS/AMSU-A observations in cases of up to 80% partial cloud cover, with only a small degradation in accuracy compared to that obtained in clear scenes. Susskind and Atlas show that these findings hold for real AIRS/AMSU-A soundings as well. For data assimilation purposes, this small degradation in accuracy is more than offset by a significant increase in spatial coverage (roughly 50% of global cases were accepted, compared to 3.6% of the global cases being diagnosed as clear), and assimilation of AIRS temperature soundings in partially cloudy conditions resulted in a larger improvement in forecast skill than when AIRS soundings were assimilated only under clear conditions. Alternatively, derived AIRS clear column radiances under partial cloud cover could also be used for data assimilation purposes. Further improvements in AIRS sounding methodology have been made since the results shown in Susskind and Atlas . A new version of the AIRS/AMSU-A retrieval algorithm, Version 4.0, was delivered to the Goddard DAAC in February 2005 for production of AIRS derived products, including clear column radiances. The major improvement in the Version 4.0 retrieval algorithm is with regard to a more flexible, parameter dependent, quality control. Results are shown of the accuracy and spatial distribution of temperature-moisture profiles and clear column radiances derived from AIRS/AMSU-A as a function of fractional cloud cover using the Version 4.0 algorithm. Use of the Version 4.0 AIRS temperature profiles increased the positive forecast impact arising from AIRS retrievals relative to what was shown in Susskind and Atlas .

Evaluation of validation of a fully instrumented Hüttlin HKC 05-TJ laboratory-scale fluidized bed granulator.

PubMed

Wöstheinrich, K; Schmidt, P C

2000-06-01

The instrumentation and validation of a laboratory-scale fluidized bed apparatus is described. For continuous control of the process, the apparatus is instrumented with sensors for temperature, relative humidity (RH), and air velocity. Conditions of inlet air, fluidizing air, product, and exhaust air were determined. The temperature sensors were calibrated at temperatures of 0.0 degree C and 99.9 degrees C. The calibration of the humidity sensors covered the range from 12% RH to 98% RH using saturated electrolyte solutions. The calibration of the anemometer took place in a wind tunnel at defined air velocities. The calibrations led to satisfying results concerning sensitivity and precision. To evaluate the reproducibility of the process, 15 granules were prepared under identical conditions. The influence of the type of pump used for delivering the granulating liquid was investigated. Particle size distribution, bulk density, and tapped density were determined. Granules were tableted on a rotary press at four different compression force levels, followed by determination of tablet properties such as weight, crushing strength, and disintegration time. The apparatus was found to produce granules with good reproducibility concerning the granule and tablet properties.

Simulation of a Severe Autumn/Winter Drought in Eastern China by Regional Atmospheric Modeling System(RAMS)

NASA Astrophysics Data System (ADS)

Meng, Chunchun; Ma, Yaoming

2016-04-01

Compared with European Centre for Medium-Range Weather Forecasts (ERA-interim) Reanalysis data and Global Summary Of Day (GSOD) observation data, the outcomes from RAMS of the 2008/2009 severe autumn/winter drought in eastern china are analyzed in this study. The reanalysis data showed that most parts of north China are controlled by northwest wind which was accompanied by cold air, the warm and moist air from South Sea is so weak to meet with cold air, therefore forming a circulation which is unfavorable for the formation of precipitation over Eastern China. RAMS performs very well over the simulation of this atmospheric circulation, so do the rainfall and air temperature over China and where the drought occurred. Meanwhile, the simulation of the time series of precipitation and temperature behaves excellent, the square of correlation coefficient between simulations and observations reached above 0.8. Although the performance of RAMS on this drought simulation is fairly accurate, there is amount of research work to be continued to complete a more realistic simulation. KEY WORDS RAMS; severe drought; numerical simulation; atmospheric circulation; precipitation and air temperature

Study on Al2O3 extraction from activated coal gangue under different calcination atmospheres

NASA Astrophysics Data System (ADS)

Dong, Ling; Liang, Xinxing; Song, Qiang; Gao, Gewu; Song, Lihua; Shu, Yuanfeng; Shu, Xinqian

2017-12-01

Coal gangue was calcinated under air, nitrogen, carbon dioxide, air-hydrogen, and hydrogen atmospheres. The effects of different calcination temperatures and atmospheres on the mineral composition of activated coal gangue were investigated by X-ray diffraction. Moreover, the acid leaching kinetics of aluminum oxide from coal gangue was investigated with sulfuric acid. It showed that the air atmosphere promoted kaolinite decomposition during coal gangue calcination. The hydrogen atmosphere promoted the activation and decomposition of kaolinite at reaction temperatures exceeding 650°C. The carbon dioxide atmosphere eliminated the influence of residual carbon on coal gangue. When the ratio of acid/coal gangue was 1.5 and reaction temperature was 650°C, the sulfuric acid leaching rate under air, air-hydrogen, carbon dioxide, hydrogen and nitrogen atmospheres were 93.66%, 90.90%, 84.06%, 81.91% and 77.54% respectively. The acid leaching reaction process conformed to unreacted shrinking core model of particle unchanged, and was controlled by the interfacial chemical reaction. The reaction kinetic equation for the leaching process was 1-(1-x)1/3=kt with an apparent activation energy of 48.97 kJ/mol.

Bias Correction for Assimilation of Retrieved AIRS Profiles of Temperature and Humidity

NASA Technical Reports Server (NTRS)

Blankenship, Clay; Zavodsky, Brad; Blackwell, William

2014-01-01

Atmospheric Infrared Sounder (AIRS) is a hyperspectral radiometer aboard NASA's Aqua satellite designed to measure atmospheric profiles of temperature and humidity. AIRS retrievals are assimilated into the Weather Research and Forecasting (WRF) model over the North Pacific for some cases involving "atmospheric rivers". These events bring a large flux of water vapor to the west coast of North America and often lead to extreme precipitation in the coastal mountain ranges. An advantage of assimilating retrievals rather than radiances is that information in partly cloudy fields of view can be used. Two different Level 2 AIRS retrieval products are compared: the Version 6 AIRS Science Team standard retrievals and a neural net retrieval from MIT. Before assimilation, a bias correction is applied to adjust each layer of retrieved temperature and humidity so the layer mean values agree with a short-term model climatology. WRF runs assimilating each of the products are compared against each other and against a control run with no assimilation. This paper will describe the bias correction technique and results from forecasts evaluated by validation against a Total Precipitable Water (TPW) product from CIRA and against Global Forecast System (GFS) analyses.

Measuring surface temperature and grading pathological changes of airway tissue in a canine model of inhalational thermal injury.

PubMed

Zhao, Ran; Di, La-na; Zhao, Xiao-zhuo; Wang, Cheng; Zhang, Guo-an

2013-06-01

Airway tissue shows unexpected invulnerability to heated air. The mechanisms of this phenomenon are open to debate. This study was designed to measure the surface temperatures at different locations of the airway, and to explore the relationship between the tissue's surface temperature and injury severity. Twenty dogs were randomly divided into four groups, including three experimental groups (six dogs in each) to inhale heated air at 70-80 °C (group I), 150-160 °C (group II) and 310-320 °C (group III) and a control group (two dogs, only for histological observation). Injury time was 20 min. Mucosal surface temperatures of the epiglottis (point A), cricoid cartilage (point B) and lower trachea (point C) were measured. Dogs in group I-III were divided into three subgroups (two in each), to be assayed at 12, 24 and 36 h after injury, respectively. For each dog, four tissue parts (epiglottis, larynx, lower trachea and terminal bronchiole) were microscopically observed and graded according to an original pathological scoring system (score range: 0-27). Surface temperatures of the airway mucosa increased slowly to 40.60±3.29 °C, and the highest peak temperature was 48.3 °C (group III, point A). The pathological score of burned tissues was 4.12±4.94 (0.0-18.0), suggesting slight to moderate injuries. Air temperature and airway location both influenced mucosal temperature and pathological scores very significantly, and there was a very significant positive correlation between tissue temperature and injury severity. Compared to the inhalational air hyperthermia, airway surface temperature was much lower, but was still positively correlated with thermal injury severity. Copyright © 2012 Elsevier Ltd and ISBI. All rights reserved.

40 CFR 91.309 - Engine intake air temperature measurement.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 20 2014-07-01 2013-07-01 true Engine intake air temperature... Provisions § 91.309 Engine intake air temperature measurement. (a) Engine intake air temperature measurement... the supply system or in the air stream entering the engine. (b) The temperature measurements must be...

40 CFR 91.309 - Engine intake air temperature measurement.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 21 2012-07-01 2012-07-01 false Engine intake air temperature... Provisions § 91.309 Engine intake air temperature measurement. (a) Engine intake air temperature measurement... the supply system or in the air stream entering the engine. (b) The temperature measurements must be...

40 CFR 91.309 - Engine intake air temperature measurement.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 21 2013-07-01 2013-07-01 false Engine intake air temperature... Provisions § 91.309 Engine intake air temperature measurement. (a) Engine intake air temperature measurement... the supply system or in the air stream entering the engine. (b) The temperature measurements must be...

40 CFR 91.309 - Engine intake air temperature measurement.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 20 2011-07-01 2011-07-01 false Engine intake air temperature... Provisions § 91.309 Engine intake air temperature measurement. (a) Engine intake air temperature measurement... the supply system or in the air stream entering the engine. (b) The temperature measurements must be...

Changes in air temperature and its relation to ambulance transports due to heat stroke in all 47 prefectures of Japan.

PubMed

Murakami, Shoko; Miyatake, Nobuyuki; Sakano, Noriko

2012-09-01

Changes in air temperature and its relation to ambulance transports due to heat stroke in all 47 prefectures, in Japan were evaluated. Data on air temperature were obtained from the Japanese Meteorological Agency. Data on ambulance transports due to heat stroke was directly obtained from the Fire and Disaster Management Agency, Japan. We also used the number of deaths due to heat stroke from the Ministry of Health, Labour and Welfare, Japan, and population data from the Ministry of Internal Affairs and Communications. Chronological changes in parameters of air temperature were analyzed. In addition, the relation between air temperature and ambulance transports due to heat stroke in August 2010 was also evaluated by using an ecological study. Positive and significant changes in the parameters of air temperature that is, the mean air temperature, mean of the highest air temperature, and mean of the lowest air temperature were noted in all 47 prefectures. In addition, changes in air temperature were accelerated when adjusted for observation years. Ambulance transports due to heat stroke was significantly correlated with air temperature in the ecological study. The highest air temperature was significantly linked to ambulance transports due to heat stroke, especially in elderly subjects. Global warming was demonstrated in all 47 prefectures in Japan. In addition, the higher air temperature was closely associated with higher ambulance transports due to heat stroke in Japan.

Increased Air Temperature during Simulated Autumn Conditions Does Not Increase Photosynthetic Carbon Gain But Affects the Dissipation of Excess Energy in Seedlings of the Evergreen Conifer Jack Pine1[OA

PubMed Central

Busch, Florian; Hüner, Norman P.A.; Ensminger, Ingo

2007-01-01

Temperature and daylength act as environmental signals that determine the length of the growing season in boreal evergreen conifers. Climate change might affect the seasonal development of these trees, as they will experience naturally decreasing daylength during autumn, while at the same time warmer air temperature will maintain photosynthesis and respiration. We characterized the down-regulation of photosynthetic gas exchange and the mechanisms involved in the dissipation of energy in Jack pine (Pinus banksiana) in controlled environments during a simulated summer-autumn transition under natural conditions and conditions with altered air temperature and photoperiod. Using a factorial design, we dissected the effects of daylength and temperature. Control plants were grown at either warm summer conditions with 16-h photoperiod and 22°C or conditions representing a cool autumn with 8 h/7°C. To assess the impact of photoperiod and temperature on photosynthesis and energy dissipation, plants were also grown under either cold summer (16-h photoperiod/7°C) or warm autumn conditions (8-h photoperiod/22°C). Photosynthetic gas exchange was affected by both daylength and temperature. Assimilation and respiration rates under warm autumn conditions were only about one-half of the summer values but were similar to values obtained for cold summer and natural autumn treatments. In contrast, photosynthetic efficiency was largely determined by temperature but not by daylength. Plants of different treatments followed different strategies for dissipating excess energy. Whereas in the warm summer treatment safe dissipation of excess energy was facilitated via zeaxanthin, in all other treatments dissipation of excess energy was facilitated predominantly via increased aggregation of the light-harvesting complex of photosystem II. These differences were accompanied by a lower deepoxidation state and larger amounts of β-carotene in the warm autumn treatment as well as by changes in the abundance of thylakoid membrane proteins compared to the summer condition. We conclude that photoperiod control of dormancy in Jack pine appears to negate any potential for an increased carbon gain associated with higher temperatures during the autumn season. PMID:17259287

Increased air temperature during simulated autumn conditions does not increase photosynthetic carbon gain but affects the dissipation of excess energy in seedlings of the evergreen conifer Jack pine.

PubMed

Busch, Florian; Hüner, Norman P A; Ensminger, Ingo

2007-03-01

Temperature and daylength act as environmental signals that determine the length of the growing season in boreal evergreen conifers. Climate change might affect the seasonal development of these trees, as they will experience naturally decreasing daylength during autumn, while at the same time warmer air temperature will maintain photosynthesis and respiration. We characterized the down-regulation of photosynthetic gas exchange and the mechanisms involved in the dissipation of energy in Jack pine (Pinus banksiana) in controlled environments during a simulated summer-autumn transition under natural conditions and conditions with altered air temperature and photoperiod. Using a factorial design, we dissected the effects of daylength and temperature. Control plants were grown at either warm summer conditions with 16-h photoperiod and 22 degrees C or conditions representing a cool autumn with 8 h/7 degrees C. To assess the impact of photoperiod and temperature on photosynthesis and energy dissipation, plants were also grown under either cold summer (16-h photoperiod/7 degrees C) or warm autumn conditions (8-h photoperiod/22 degrees C). Photosynthetic gas exchange was affected by both daylength and temperature. Assimilation and respiration rates under warm autumn conditions were only about one-half of the summer values but were similar to values obtained for cold summer and natural autumn treatments. In contrast, photosynthetic efficiency was largely determined by temperature but not by daylength. Plants of different treatments followed different strategies for dissipating excess energy. Whereas in the warm summer treatment safe dissipation of excess energy was facilitated via zeaxanthin, in all other treatments dissipation of excess energy was facilitated predominantly via increased aggregation of the light-harvesting complex of photosystem II. These differences were accompanied by a lower deepoxidation state and larger amounts of beta-carotene in the warm autumn treatment as well as by changes in the abundance of thylakoid membrane proteins compared to the summer condition. We conclude that photoperiod control of dormancy in Jack pine appears to negate any potential for an increased carbon gain associated with higher temperatures during the autumn season.

Variation in Rising Limb of Colorado River Snowmelt Runoff Hydrograph Controlled by Dust Radiative Forcing in Snow

NASA Astrophysics Data System (ADS)

Painter, Thomas H.; Skiles, S. McKenzie; Deems, Jeffrey S.; Brandt, W. Tyler; Dozier, Jeff

2018-01-01

Common practice and conventional wisdom hold that fluctuations in air temperature control interannual variability in snowmelt and subsequent river runoff. However, recent observations in the Upper Colorado River Basin confirm that net solar radiation and by extension radiative forcing by dust deposited on snow cover exerts the primary forcing on snowmelt. We show that the variation in the shape of the rising limb of the annual hydrograph is controlled by variability in dust radiative forcing and surprisingly is independent of variations in winter and spring air temperatures. These observations suggest that hydroclimatic modeling must be improved to account for aerosol forcings of the water cycle. Anthropogenic climate change will likely reduce total snow accumulations and cause snowmelt runoff to occur earlier. However, dust radiative forcing of snowmelt is likely consuming important adaptive capacity that would allow human and natural systems to be more resilient to changing hydroclimatic conditions.

Biomass torrefaction characteristics in inert and oxidative atmospheres at various superficial velocities.

PubMed

Chen, Wei-Hsin; Lu, Ke-Miao; Liu, Shih-Hsien; Tsai, Chi-Ming; Lee, Wen-Jhy; Lin, Ta-Chang

2013-10-01

The reaction characteristics of four biomass materials (i.e. oil palm fiber, coconut fiber, eucalyptus, and Cryptomeria japonica) with non-oxidative and oxidative torrefaction at various superficial velocities are investigated where nitrogen and air are used as carrier gases. Three torrefaction temperatures of 250, 300, and 350 °C are considered. At a given temperature, the solid yield of biomass is not affected by N2 superficial velocity, revealing that the thermal degradation is controlled by heat and mass transfer in biomass. Increasing air superficial velocity decreases the solid yield, especially in oil palm fiber and coconut fiber, implying that the torrefaction reaction of biomass is dominated by surface oxidation. There exists an upper limit of air superficial velocity in the decrement of solid yield, suggesting that beyond this limit the thermal degradation of biomass is no longer governed by surface oxidation, but rather is controlled by internal mass transport. Copyright © 2013 Elsevier Ltd. All rights reserved.

Air density dependence of the soft X-ray PTW 34013 ionization chamber.

PubMed

Torres Del Río, Julia; Forastero, Cristina; Tornero-López, Ana M; López, Jesús J; Guirado, Damián; Perez-Calatayud, José; Lallena, Antonio M

2018-02-01

We studied the dependence on air density of the response of the PTW 34013 ionization chamber, recently upgraded for dosimetry control of low energy X-ray beams. Measurements were performed by changing the pressure conditions inside a pressure chamber. The behavior of the measurements against the air density inside this chamber was analyzed. X-ray beams generated with 50, 70, 100, 150 and 200 kVp and the two electrometer polarities were considered. For all beams studied, measurements corrected with the conventional temperature and pressure factor showed a residual dependence on the air density that was described with a linear function of the air density. For the 50 and 70 kVp beams, corrected measurements remained ∼1% smaller than the value found at standard pressure/temperature conditions, for both electrometer polarities and for the air density range typical in clinical conditions. For air densities smaller than the standard one, measurements found for 100, 150 and 200 kVp beams were below or above the value found at standard pressure and temperature when the negative or positive electrometer polarities were used, respectively. The differences with the measurements at standard conditions were less than 1% for the 100 kVp beam and below 4% for the other two beams. The PTW 34013 ionization chamber showed a dependence on the air density that is not properly described with the usual temperature and pressure correction factor. This residual dependence is negligible for low energy beams, for which this chamber is recommended, but is more substantial for beams with energy above 80 kVp. Copyright © 2018 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Compact Analyzer/Controller For Oxygen-Enrichment System

NASA Technical Reports Server (NTRS)

Puster, Richard L.; Singh, Jag J.; Sprinkle, Danny R.

1990-01-01

System controls hypersonic air-breathing engine tests. Compact analyzer/controller developed, built, and tested in small-scale wind tunnel prototype of the 8' HTT (High-Temperature Tunnel). Monitors level of oxygen and controls addition of liquid oxygen to enrich atmosphere for combustion. Ensures meaningful ground tests of hypersonic engines in range of speeds from mach 4 to mach 7.

Model-based analysis of environmental controls over ecosystem primary production in an alpine tundra dry meadow

DOE PAGES

Fan, Zhaosheng; Neff, Jason C.; Wieder, William R.

2016-02-10

We investigated several key limiting factors that control alpine tundra productivity by developing an ecosystem biogeochemistry model. The model simulates the coupled cycling of carbon (C), nitrogen (N), and phosphorus (P) and their interactions with gross primary production (GPP). It was parameterized with field observations from an alpine dry meadow ecosystem using a global optimization strategy to estimate the unknown parameters. The model, along with the estimated parameters, was first validated against independent data and then used to examine the environmental controls over plant productivity. Our results show that air temperature is the strongest limiting factor to GPP in themore » early growing season, N availability becomes important during the middle portion of the growing season, and soil moisture is the strongest limiting factors by late in the growing season. Overall, the controls over GPP during the growing season, from strongest to weakest, are soil moisture content, air temperature, N availability, and P availability. This simulation provides testable predictions of the shifting nature of physical and nutrient limitations on plant growth. The model also indicates that changing environmental conditions in the alpine will likely lead to changes in productivity. For example, warming eliminates the control of P availability on GPP and makes N availability surpass air temperature to become the second strongest limiting factor. In contrast, an increase in atmospheric nutrient deposition eliminates the control of N availability and enhances the importance of P availability. Furthermore, these analyses provide a quantitative and conceptual framework that can be used to test predictions and refine ecological analyses at this long-term ecological research site.« less

Model-based analysis of environmental controls over ecosystem primary production in an alpine tundra dry meadow

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

Fan, Zhaosheng; Neff, Jason C.; Wieder, William R.

We investigated several key limiting factors that control alpine tundra productivity by developing an ecosystem biogeochemistry model. The model simulates the coupled cycling of carbon (C), nitrogen (N), and phosphorus (P) and their interactions with gross primary production (GPP). It was parameterized with field observations from an alpine dry meadow ecosystem using a global optimization strategy to estimate the unknown parameters. The model, along with the estimated parameters, was first validated against independent data and then used to examine the environmental controls over plant productivity. Our results show that air temperature is the strongest limiting factor to GPP in themore » early growing season, N availability becomes important during the middle portion of the growing season, and soil moisture is the strongest limiting factors by late in the growing season. Overall, the controls over GPP during the growing season, from strongest to weakest, are soil moisture content, air temperature, N availability, and P availability. This simulation provides testable predictions of the shifting nature of physical and nutrient limitations on plant growth. The model also indicates that changing environmental conditions in the alpine will likely lead to changes in productivity. For example, warming eliminates the control of P availability on GPP and makes N availability surpass air temperature to become the second strongest limiting factor. In contrast, an increase in atmospheric nutrient deposition eliminates the control of N availability and enhances the importance of P availability. Furthermore, these analyses provide a quantitative and conceptual framework that can be used to test predictions and refine ecological analyses at this long-term ecological research site.« less

Microclimate Data Improve Predictions of Insect Abundance Models Based on Calibrated Spatiotemporal Temperatures.

PubMed

Rebaudo, François; Faye, Emile; Dangles, Olivier

2016-01-01

A large body of literature has recently recognized the role of microclimates in controlling the physiology and ecology of species, yet the relevance of fine-scale climatic data for modeling species performance and distribution remains a matter of debate. Using a 6-year monitoring of three potato moth species, major crop pests in the tropical Andes, we asked whether the spatiotemporal resolution of temperature data affect the predictions of models of moth performance and distribution. For this, we used three different climatic data sets: (i) the WorldClim dataset (global dataset), (ii) air temperature recorded using data loggers (weather station dataset), and (iii) air crop canopy temperature (microclimate dataset). We developed a statistical procedure to calibrate all datasets to monthly and yearly variation in temperatures, while keeping both spatial and temporal variances (air monthly temperature at 1 km² for the WorldClim dataset, air hourly temperature for the weather station, and air minute temperature over 250 m radius disks for the microclimate dataset). Then, we computed pest performances based on these three datasets. Results for temperature ranging from 9 to 11°C revealed discrepancies in the simulation outputs in both survival and development rates depending on the spatiotemporal resolution of the temperature dataset. Temperature and simulated pest performances were then combined into multiple linear regression models to compare predicted vs. field data. We used an additional set of study sites to test the ability of the results of our model to be extrapolated over larger scales. Results showed that the model implemented with microclimatic data best predicted observed pest abundances for our study sites, but was less accurate than the global dataset model when performed at larger scales. Our simulations therefore stress the importance to consider different temperature datasets depending on the issue to be solved in order to accurately predict species abundances. In conclusion, keeping in mind that the mismatch between the size of organisms and the scale at which climate data are collected and modeled remains a key issue, temperature dataset selection should be balanced by the desired output spatiotemporal scale for better predicting pest dynamics and developing efficient pest management strategies.

Microclimate Data Improve Predictions of Insect Abundance Models Based on Calibrated Spatiotemporal Temperatures

PubMed Central

Rebaudo, François; Faye, Emile; Dangles, Olivier

2016-01-01

A large body of literature has recently recognized the role of microclimates in controlling the physiology and ecology of species, yet the relevance of fine-scale climatic data for modeling species performance and distribution remains a matter of debate. Using a 6-year monitoring of three potato moth species, major crop pests in the tropical Andes, we asked whether the spatiotemporal resolution of temperature data affect the predictions of models of moth performance and distribution. For this, we used three different climatic data sets: (i) the WorldClim dataset (global dataset), (ii) air temperature recorded using data loggers (weather station dataset), and (iii) air crop canopy temperature (microclimate dataset). We developed a statistical procedure to calibrate all datasets to monthly and yearly variation in temperatures, while keeping both spatial and temporal variances (air monthly temperature at 1 km² for the WorldClim dataset, air hourly temperature for the weather station, and air minute temperature over 250 m radius disks for the microclimate dataset). Then, we computed pest performances based on these three datasets. Results for temperature ranging from 9 to 11°C revealed discrepancies in the simulation outputs in both survival and development rates depending on the spatiotemporal resolution of the temperature dataset. Temperature and simulated pest performances were then combined into multiple linear regression models to compare predicted vs. field data. We used an additional set of study sites to test the ability of the results of our model to be extrapolated over larger scales. Results showed that the model implemented with microclimatic data best predicted observed pest abundances for our study sites, but was less accurate than the global dataset model when performed at larger scales. Our simulations therefore stress the importance to consider different temperature datasets depending on the issue to be solved in order to accurately predict species abundances. In conclusion, keeping in mind that the mismatch between the size of organisms and the scale at which climate data are collected and modeled remains a key issue, temperature dataset selection should be balanced by the desired output spatiotemporal scale for better predicting pest dynamics and developing efficient pest management strategies. PMID:27148077

Experimental Evaluation of Fuzzy Logic Control of a Flexible Arm Manipulator

DTIC Science & Technology

1993-12-09

temperature into a fuzzy context), and humidity is musty, Then air conditioner power is high. The database and knowledge base combine to form the...this case, the output, perhaps air conditioner power, would be medium to a degree of 50%. However, as shown in Table 3.2, Oare are more possible...OF WASHINGTON AFIT/CI/CIA-93-167 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSORING/MONITORING DEPARTMENI OF THE AIR FORCE AGENCY

Cairo consensus on the IVF laboratory environment and air quality: report of an expert meeting.

PubMed

Mortimer, D; Cohen, J; Mortimer, S T; Fawzy, M; McCulloh, D H; Morbeck, D E; Pollet-Villard, X; Mansour, R T; Brison, D R; Doshi, A; Harper, J C; Swain, J E; Gilligan, A V

2018-03-02

This proceedings report presents the outcomes from an international Expert Meeting to establish a consensus on the recommended technical and operational requirements for air quality within modern assisted reproduction technology (ART) laboratories. Topics considered included design and construction of the facility, as well as its heating, ventilation and air conditioning system; control of particulates, micro-organisms (bacteria, fungi and viruses) and volatile organic compounds (VOCs) within critical areas; safe cleaning practices; operational practices to optimize air quality while minimizing physicochemical risks to gametes and embryos (temperature control versus air flow); and appropriate infection-control practices that minimize exposure to VOC. More than 50 consensus points were established under the general headings of assessing site suitability, basic design criteria for new construction, and laboratory commissioning and ongoing VOC management. These consensus points should be considered as aspirational benchmarks for existing ART laboratories, and as guidelines for the construction of new ART laboratories. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

Monitoring of soil and air-rock temperatures in the Western Massif of the Picos de Europa (Spain)

NASA Astrophysics Data System (ADS)

Ruiz-Fernández, Jesús; Vieira, Gonçalo; García, Cristina

2013-04-01

In this paper we study the ground thermal regime and air-rock interface in the Western Massif of the Picos de Europa (Cantabrian Range, Spain). This calcareous massif is highly affected by karstification processes. Quaternary glaciers, fluvio-torrential processes and present-day periglacial processes also contribute to explain the landforms present in this massif. Up to 9 dataloggers were installed during 6 years in different sites in terms of altitude, orientation, slope and geomorpolohical setting recording temperatures every two hours. The number of freeze-thaw cycles in the soil(between 0 and 16) was controlled by the depth of the snow cover. The temperatures in the interface rock-air showed between 30-60 cycles, reaching 119 and 130 during the year 2007-2008. Extreme minimum temperatures in the soil oscillate between 0.3 and -6.3, while in the rocky walls the loggers recorded temperatures between -7.3 and -14.3°C. Monitoring of soil temperatures around the ice patch - the only one in the massif today - resulted in slightly negative mean annual temperatures. These conditions may reveal the existence of sporadic permafrost on debris that cover the ice patch. Both the buried ice and the permafrost are in disequilibrium with the current environmental conditions of the massif.

Estimation of the temperature spatial variability in confined spaces based on thermal imaging

NASA Astrophysics Data System (ADS)

Augustyn, Grzegorz; Jurasz, Jakub; Jurczyk, Krzysztof; Korbiel, Tomasz; Mikulik, Jerzy; Pawlik, Marcin; Rumin, Rafał

2017-11-01

In developed countries the salaries of office workers are several times higher than the total cost of maintaining and operating the building. Therefore even a small improvement in human work productivity and performance as a result of enhancing the quality of their work environment may lead to a meaningful economic benefits. The air temperature is the most commonly used indicator in assessing the indoor environment quality. What is more, it is well known that thermal comfort has the biggest impact on employees performance and their ability to work efficiently. In majority of office buildings, indoor temperature is managed by heating, ventilation and air conditioning (HVAC) appliances. However the way how they are currently managed and controlled leads to the nonhomogeneous distribution of temperature in certain space. An approach to determining the spatial variability of temperature in confined spaces was introduced based on thermal imaging temperature measurements. The conducted research and obtained results enabled positive verification of the method and creation of surface plot illustrating the temperature variability.

Impacts of seasonal air and soil temperatures on photosynthesis in Scots pine trees.

PubMed

Strand, Martin; Lundmark, Tomas; Söderbergh, Ingrid; Mellander, Per-Erik

2002-08-01

Seasonal courses of light-saturated rate of net photosynthesis (A360) and stomatal conductance (gs) were examined in detached 1-year-old needles of Scots pine (Pinus sylvestris L.) from early April to mid-November. To evaluate the effects of soil frost and low soil temperatures on gas exchange, the extent and duration of soil frost, as well as the onset of soil warming, were manipulated in the field. During spring, early summer and autumn, the patterns of A360 and gs in needles from the control and warm-soil plots were generally strongly related to daily mean air temperatures and the frequency of severe frost. The warm-soil treatment had little effect on gas exchange, although mean soil temperature in the warm-soil plot was 3.8 degrees C higher than in the control plot during spring and summer, indicating that A360 and gs in needles from control trees were not limited by low soil temperature alone. In contrast, prolonged exposure to soil temperatures slightly above 0 degrees C severely restricted recovery of A360 and especially gs in needles from the cold-soil treatment during spring and early summer; however, full recovery of both A360 and gs occurred in late summer. We conclude that inhibition of A360 by low soil temperatures is related to both stomatal closure and effects on the biochemistry of photosynthesis, the relative importance of which appeared to vary during spring and early summer. During the autumn, soil temperatures as low as 8 degrees C did not affect either A360 or gs.

Using spacecraft trace contaminant control systems to cure sick building syndrome

NASA Technical Reports Server (NTRS)

Graf, John C.

1994-01-01

Many residential and commercial buildings with centralized, recirculating, heating ventilation and air conditioning systems suffer from 'Sick Building Syndrome.' Ventilation rates are reduced to save energy costs, synthetic building materials off-gas contaminants, and unsafe levels of volatile organic compounds (VOC's) accumulate. These unsafe levels of contaminants can cause irritation of eyes and throat, fatigue and dizziness to building occupants. Increased ventilation, the primary method of treating Sick Building Syndrome is expensive (due to increased energy costs) and recently, the effectiveness of increased ventilation has been questioned. On spacecraft venting is not allowed, so the primary methods of air quality control are; source control, active filtering, and destruction of VOC's. Four non-venting contaminant removal technologies; strict material selection to provide source control, ambient temperature catalytic oxidation, photocatalytic oxidation, and uptake by higher plants, may have potential application for indoor air quality control.

[Life support of the Mars exploration crew. Control of a zeolite system for carbon dioxide removal from space cabin air within a closed air regeneration cycle].

PubMed

Chekov, Iu F

2009-01-01

The author describes a zeolite system for carbon dioxide removal integrated into a closed air regeneration cycle aboard spacecraft. The continuous operation of a double-adsorbent regeneration system with pCO2-dependable productivity is maintained through programmable setting of adsorption (desorption) semicycle time. The optimal system regulation curve is presented within the space of statistical performance family obtained in quasi-steady operating modes with controlled parameters of the recurrent adsorption-desorption cycle. The automatically changing system productivity ensures continuous intake of concentrated CO2. Control of the adsorption-desorption process is based on calculation of the differential adsorption (desorption) heat from gradient of adsorbent and test inert substance temperatures. The adaptive algorithm of digital control is implemented through the standard spacecraft interface with the board computer system and programmable microprocessor-based controllers.

Estimation of Surface Air Temperature from MODIS 1km Resolution Land Surface Temperature Over Northern China

NASA Technical Reports Server (NTRS)

Shen, Suhung; Leptoukh, Gregory G.; Gerasimov, Irina

2010-01-01

Surface air temperature is a critical variable to describe the energy and water cycle of the Earth-atmosphere system and is a key input element for hydrology and land surface models. It is a very important variable in agricultural applications and climate change studies. This is a preliminary study to examine statistical relationships between ground meteorological station measured surface daily maximum/minimum air temperature and satellite remotely sensed land surface temperature from MODIS over the dry and semiarid regions of northern China. Studies were conducted for both MODIS-Terra and MODIS-Aqua by using year 2009 data. Results indicate that the relationships between surface air temperature and remotely sensed land surface temperature are statistically significant. The relationships between the maximum air temperature and daytime land surface temperature depends significantly on land surface types and vegetation index, but the minimum air temperature and nighttime land surface temperature has little dependence on the surface conditions. Based on linear regression relationship between surface air temperature and MODIS land surface temperature, surface maximum and minimum air temperatures are estimated from 1km MODIS land surface temperature under clear sky conditions. The statistical errors (sigma) of the estimated daily maximum (minimum) air temperature is about 3.8 C(3.7 C).

Global soil consumption of atmospheric carbon monoxide: an analysis using a process-based biogeochemistry model

NASA Astrophysics Data System (ADS)

Liu, Licheng; Zhuang, Qianlai; Zhu, Qing; Liu, Shaoqing; van Asperen, Hella; Pihlatie, Mari

2018-06-01

Carbon monoxide (CO) plays an important role in controlling the oxidizing capacity of the atmosphere by reacting with OH radicals that affect atmospheric methane (CH4) dynamics. We develop a process-based biogeochemistry model to quantify the CO exchange between soils and the atmosphere with a 5 min internal time step at the global scale. The model is parameterized using the CO flux data from the field and laboratory experiments for 11 representative ecosystem types. The model is then extrapolated to global terrestrial ecosystems using monthly climate forcing data. Global soil gross consumption, gross production, and net flux of the atmospheric CO are estimated to be from -197 to -180, 34 to 36, and -163 to -145 Tg CO yr-1 (1 Tg = 1012 g), respectively, when the model is driven with satellite-based atmospheric CO concentration data during 2000-2013. Tropical evergreen forest, savanna and deciduous forest areas are the largest sinks at 123 Tg CO yr-1. The soil CO gross consumption is sensitive to air temperature and atmospheric CO concentration, while the gross production is sensitive to soil organic carbon (SOC) stock and air temperature. By assuming that the spatially distributed atmospheric CO concentrations ( ˜ 128 ppbv) are not changing over time, the global mean CO net deposition velocity is estimated to be 0.16-0.19 mm s-1 during the 20th century. Under the future climate scenarios, the CO deposition velocity will increase at a rate of 0.0002-0.0013 mm s-1 yr-1 during 2014-2100, reaching 0.20-0.30 mm s-1 by the end of the 21st century, primarily due to the increasing temperature. Areas near the Equator, the eastern US, Europe and eastern Asia will be the largest sinks due to optimum soil moisture and high temperature. The annual global soil net flux of atmospheric CO is primarily controlled by air temperature, soil temperature, SOC and atmospheric CO concentrations, while its monthly variation is mainly determined by air temperature, precipitation, soil temperature and soil moisture.

Multi-Objectives Optimization of Ventilation Controllers for Passive Cooling in Residential Buildings

PubMed Central

Grygierek, Krzysztof; Ferdyn-Grygierek, Joanna

2018-01-01

An inappropriate indoor climate, mostly indoor temperature, may cause occupants’ discomfort. There are a great number of air conditioning systems that make it possible to maintain the required thermal comfort. Their installation, however, involves high investment costs and high energy demand. The study analyses the possibilities of limiting too high a temperature in residential buildings using passive cooling by means of ventilation with ambient cool air. A fuzzy logic controller whose aim is to control mechanical ventilation has been proposed and optimized. In order to optimize the controller, the modified Multiobjective Evolutionary Algorithm, based on the Strength Pareto Evolutionary Algorithm, has been adopted. The optimization algorithm has been implemented in MATLAB®, which is coupled by MLE+ with EnergyPlus for performing dynamic co-simulation between the programs. The example of a single detached building shows that the occupants’ thermal comfort in a transitional climate may improve significantly owing to mechanical ventilation controlled by the suggested fuzzy logic controller. When the system is connected to the traditional cooling system, it may further bring about a decrease in cooling demand. PMID:29642525

Using Real-time Quantitative PCR to Examine the Dynamics of Soil Fungi and Bacteria in Response to Ecosystem Warming

USDA-ARS?s Scientific Manuscript database

As atmospheric trace gas concentrations and global temperatures climb, scientists are challenged to determine how microbial communities may mediate plant response to future climate change. To this end, a Temperature Free-Air Controlled Enrichment (T-FACE) experiment was implemented in a spring wheat...

Method and apparatus for controlling accidental releases of tritium

DOEpatents

Galloway, T.R.

1980-04-01

An improvement is described in a tritium control system based on a catalytic oxidation reactor wherein accidental releases of tritium into room air are controlled by flooding the catalytic oxidation reactor with hydrogen when the tritium concentration in the room air exceeds a specified limit. The sudden flooding with hydrogen heats the catalyst to a high temperature within seconds, thereby greatly increasing the catalytic oxidation rate of tritium to tritiated water vapor. Thus, the catalyst is heated only when needed. In addition to the heating effect, the hydrogen flow also swamps the tritium and further reduces the tritium release. 1 fig.

Method and apparatus for controlling accidental releases of tritium

DOEpatents

Galloway, Terry R. [Berkeley, CA

1980-04-01

An improvement in a tritium control system based on a catalytic oxidation reactor wherein accidental releases of tritium into room air are controlled by flooding the catalytic oxidation reactor with hydrogen when the tritium concentration in the room air exceeds a specified limit. The sudden flooding with hydrogen heats the catalyst to a high temperature within seconds, thereby greatly increasing the catalytic oxidation rate of tritium to tritiated water vapor. Thus, the catalyst is heated only when needed. In addition to the heating effect, the hydrogen flow also swamps the tritium and further reduces the tritium release.

What the R & D Man Needs in Scientific Furniture and Why.

ERIC Educational Resources Information Center

Hallenberg, E.X.

1964-01-01

The complexity of today's research laboratories requires a completely controllable environmental surrounding. Research facilities require carefully controlled temperatures, relative humidity, and moisture, and must be free of interference from air-borne sound, mechanical vibrations, and electrical sources. Also desirable are special power…

Two dimensional, transient catalytic combustion of CO-air on platinum

NASA Technical Reports Server (NTRS)

Sinha, N.; Bruno, C.; Bracco, F. V.

1985-01-01

The light off transient of catalytic combustion of lean CO-air mixtures in a platinum coated channel of a honeycomb monolith is studied with a model that resolves transient radial and axial gradients in both the gas and the solid. For the conditions studied it is concluded that: the initial heat release occurs near the entrance at the gas-solid interface and is controlled by heterogeneous reactions; large spatial and temporal temperature gradients occur in the solid near the entrance controlled mostly by the availability of fuel; the temperature of the solid near the entrance achieves almost its steady state value before significant heating of the back; heterogeneous reactions and the gas heated up front and flowing downstream heat the back of the solid; the overall transient time is controlled by the thermal inertia of the solid and by forced convection; radiation significantly influences both transient and steady state particularly near the entrance; the oxidation of CO occurs mostly on the catalyst and becomes diffusion controlled soon into the transient.

Thermophysiological responses caused by ballistic bullet-proof vests.

PubMed

Lehmacher, E J; Jansing, P; Küpper, T

2007-01-01

Little data is available concerning the heat stress experienced by members of staff who wear bullet-proof vests in a warm or hot environment. For this reason, knowledge is limited and, consequently, preventative advice on how to avoid heat sickness or hyperthermia is required. Skin and body temperatures, fluid loss and the heart rate of 30 persons (15 test persons versus 15 control persons) were measured in three situations typical of the test participants' job situations. Environmental data (wind velocity, air humidity, air temperature) were measured during the tests as well. Whereas there was a significant increase in skin temperatures, there was no difference in the core body temperatures of both groups. Maximum core body temperature remained well below 38 degrees C in all subjects. Test persons wearing vests showed a fluid loss of 1.1 l on average (non-vest wearers in the control group 1.0 l). There is no increased risk of heat stroke or hyperthermia for employees wearing bullet-proof vests in comparison with employees who do not wear them. Both groups, however, should be advised to ensure an adequate intake of fluid to maintain a healthy body fluid balance when working in hot environments.

Temperature differences within the detector of the Robertson-Berger sunburn meter, model 500, compared to global radiation

NASA Astrophysics Data System (ADS)

Kjeldstad, Berit; Grandum, Oddbjorn

1993-11-01

The Robertson-Berger sunburn meter, model 500, has no temperature compensation, and the effect of temperature on the instrument response has been investigated and discussed in several reports. It is recommended to control the temperature of the detector or at least measure it. The temperature sensor is recommended to be positioned within the detector unit. We have measured the temperature at three different positions in the detector: At the edge of the green filter where the phosphor layer is placed; at the glass tube covering the cathode; and, finally, the air temperature inside the instrument. These measurements have been performed outdoors since July 1991, with corresponding measurements of the global and direct solar radiation. There was no difference between the temperature of the glasstube covering the cathode and the air inside the instrument, at any radiation level. However, there was a difference between the green filter and the two others. The difference is linearly dependent on the amount of global radiation. The temperature difference, (Delta) T (temperature between the green filter and the air inside the sensor), increased 0.8 degree(s)C when the global irradiation increased by 100 W/m2. At maximum global radiation in Trondheim (latitude 63.4 degree(s)N) (Delta) T was approximately 5 - 6 K when the global radiation was about 700 W/m2. This was valid for temperatures between 7 degree(s)C and 30 degree(s)C. Only clear days were evaluated.

Design architecture for multi-zone HVAC control systems from existing single-zone systems using wireless sensor networks

NASA Astrophysics Data System (ADS)

Redfern, Andrew; Koplow, Michael; Wright, Paul

2007-01-01

Most residential heating, ventilating, and air-conditioning (HVAC) systems utilize a single zone for conditioning air throughout the entire house. While inexpensive, these systems lead to wide temperature distributions and inefficient cooling due to the difference in thermal loads in different rooms. The end result is additional cost to the end user because the house is over conditioned. To reduce the total amount of energy used in a home and to increase occupant comfort there is a need for a better control system using multiple temperature zones. Typical multi-zone systems are costly and require extensive infrastructure to function. Recent advances in wireless sensor networks (WSNs) have enabled a low cost drop-in wireless vent register control system. The register control system is controlled by a master controller unit, which collects sensor data from a distributed wireless sensor network. Each sensor node samples local settings (occupancy, light, humidity and temperature) and reports the data back to the master control unit. The master control unit compiles the incoming data and then actuates the vent resisters to control the airflow throughout the house. The control system also utilizes a smart thermostat with a movable set point to enable the user to define their given comfort levels. The new system can reduce the run time of the HVAC system and thus decreasing the amount of energy used and increasing the comfort of the home occupations.

Fine PM measurements: personal and indoor air monitoring.

PubMed

Jantunen, M; Hänninen, O; Koistinen, K; Hashim, J H

2002-12-01

This review compiles personal and indoor microenvironment particulate matter (PM) monitoring needs from recently set research objectives, most importantly the NRC published "Research Priorities for Airborne Particulate Matter (1998)". Techniques and equipment used to monitor PM personal exposures and microenvironment concentrations and the constituents of the sampled PM during the last 20 years are then reviewed. Development objectives are set and discussed for personal and microenvironment PM samplers and monitors, for filter materials, and analytical laboratory techniques for equipment calibration, filter weighing and laboratory climate control. The progress is leading towards smaller sample flows, lighter, silent, independent (battery powered) monitors with data logging capacity to store microenvironment or activity relevant sensor data, advanced flow controls and continuous recording of the concentration. The best filters are non-hygroscopic, chemically pure and inert, and physically robust against mechanical wear. Semiautomatic and primary standard equivalent positive displacement flow meters are replacing the less accurate methods in flow calibration, and also personal sampling flow rates should become mass flow controlled (with or without volumetric compensation for pressure and temperature changes). In the weighing laboratory the alternatives are climatic control (set temperature and relative humidity), and mechanically simpler thermostatic heating, air conditioning and dehumidification systems combined with numerical control of temperature, humidity and pressure effects on flow calibration and filter weighing.

Are the current thresholds, indicators, and time window for cold warning effective enough to protect cardiovascular health?

PubMed

Lin, Shao; Lawrence, Wayne R; Lin, Ziqiang; DiRienzo, Stephen; Lipton, Kevin; Dong, Guang-Hui; Leung, Ricky; Lauper, Ursula; Nasca, Philip; Stuart, Neil

2018-10-15

More extreme cold weather and larger weather variations have raised concerns regarding their effects on public health. Although prior studies assessed the effects of cold air temperature on health, especially mortality, limited studies evaluated wind chill temperatures on morbidity, and health effects under the current cold warning threshold. This study identified the thresholds, lag periods, and best indicators of extreme cold on cardiovascular disease (CVD) by comparing effects of wind chill temperatures and cold air temperatures on CVD emergency department (ED) visits in winter and winter transition months. Information was collected on 662,625 CVD ED visits from statewide hospital discharge dataset in New York State. Meteorological factors, including air temperature, wind speed, and barometric pressure were collected from National Oceanic and Atmospheric Administration. A case-crossover approach was used to assess the extreme cold-CVD relationship in winter (December-February) and transition months (November and March) after controlling for PM 2.5 . Conditional logistic regression models were employed to analyze the association between cold weather factors and CVD ED visits. We observed CVD effects occurred when wind chill temperatures were as high as -3.8 °C (25 °F), warmer than current wind chill warning standard (≤-28.8 °C or ≤-20 °F). Wind chill temperature was a more sensitive indicator of CVD ED visits during winter with temperatures ≤ -3.8 °C (25 °F) with delay effect (lag 6); however, air temperature was better during transition months for temperatures ≤ 7.2 °C (45 °F) at earlier lag days (1-3). Among all CVD subtypes, hypertension ED visit had the strongest negative association with both wind chill temperature and air temperature. This study recommends modifying the current cold warning temperature threshold given larger proportions of CVD cases are occurring at considerably higher temperatures than the current criteria. We also recommend issuing cold warnings in winter transitional months. Copyright © 2018 Elsevier B.V. All rights reserved.

Experimental study on occupant's thermal responses under the non-uniform conditions in vehicle cabin during the heating period

NASA Astrophysics Data System (ADS)

Zhang, Wencan; Chen, Jiqing; Lan, Fengchong

2014-03-01

The existing investigations on thermal comfort mostly focus on the thermal environment conditions, especially of the air-flow field and the temperature distributions in vehicle cabin. Less attention appears to direct to the thermal comfort or thermal sensation of occupants, even to the relationship between thermal conditions and thermal sensation. In this paper, a series of experiments were designed and conducted for understanding the non-uniform conditions and the occupant's thermal responses in vehicle cabin during the heating period. To accurately assess the transient temperature distribution in cabin in common daily condition, the air temperature at a number of positions is measured in a full size vehicle cabin under natural winter environment in South China by using a discrete thermocouples network. The occupant body is divided into nine segments, the skin temperature at each segment and the occupant's local thermal sensation at the head, body, upper limb and lower limb are monitored continuously. The skin temperature is observed by using a discrete thermocouples network, and the local thermal sensation is evaluated by using a seven-point thermal comfort survey questionnaire proposed by American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc(ASHRAE) Standard. The relationship between the skin temperature and the thermal sensation is discussed and regressed by statistics method. The results show that the interior air temperature is highly non-uniform over the vehicle cabin. The locations where the occupants sit have a significant effect on the occupant's thermal responses, including the skin temperature and the thermal sensation. The skin temperature and thermal sensation are quite different between body segments due to the effect of non-uniform conditions, clothing resistance, and the human thermal regulating system. A quantitative relationship between the thermal sensation and the skin temperature at each body segment of occupant in real life traffic is presented. The investigation result indicates that the skin temperature is a robust index to evaluate the thermal sensation. Applying the skin temperature to designing and controlling parameters of the heating, ventilation and air conditioning(HVAC) system may benefit the thermal comfort and reducing energy consumption.

A direct CO2 control system for ocean acidification experiments: testing effects on the coralline red algae Phymatolithon lusitanicum.

PubMed

Sordo, Laura; Santos, Rui; Reis, Joao; Shulika, Alona; Silva, Joao

2016-01-01

Most ocean acidification (OA) experimental systems rely on pH as an indirect way to control CO 2 . However, accurate pH measurements are difficult to obtain and shifts in temperature and/or salinity alter the relationship between pH and p CO 2 . Here we describe a system in which the target p CO 2 is controlled via direct analysis of p CO 2 in seawater. This direct type of control accommodates potential temperature and salinity shifts, as the target variable is directly measured instead of being estimated. Water in a header tank is permanently re-circulated through an air-water equilibrator. The equilibrated air is then routed to an infrared gas analyzer (IRGA) that measures p CO 2 and conveys this value to a Proportional-Integral-Derivative (PID) controller. The controller commands a solenoid valve that opens and closes the CO 2 flush that is bubbled into the header tank. This low-cost control system allows the maintenance of stabilized levels of p CO 2 for extended periods of time ensuring accurate experimental conditions. This system was used to study the long term effect of OA on the coralline red algae Phymatolithon lusitanicum . We found that after 11 months of high CO 2 exposure, photosynthesis increased with CO 2 as opposed to respiration, which was positively affected by temperature. Results showed that this system is adequate to run long-term OA experiments and can be easily adapted to test other relevant variables simultaneously with CO 2 , such as temperature, irradiance and nutrients.

A direct CO2 control system for ocean acidification experiments: testing effects on the coralline red algae Phymatolithon lusitanicum

PubMed Central

Santos, Rui; Reis, Joao; Shulika, Alona

2016-01-01

Most ocean acidification (OA) experimental systems rely on pH as an indirect way to control CO2. However, accurate pH measurements are difficult to obtain and shifts in temperature and/or salinity alter the relationship between pH and pCO2. Here we describe a system in which the target pCO2 is controlled via direct analysis of pCO2 in seawater. This direct type of control accommodates potential temperature and salinity shifts, as the target variable is directly measured instead of being estimated. Water in a header tank is permanently re-circulated through an air-water equilibrator. The equilibrated air is then routed to an infrared gas analyzer (IRGA) that measures pCO2 and conveys this value to a Proportional-Integral-Derivative (PID) controller. The controller commands a solenoid valve that opens and closes the CO2 flush that is bubbled into the header tank. This low-cost control system allows the maintenance of stabilized levels of pCO2 for extended periods of time ensuring accurate experimental conditions. This system was used to study the long term effect of OA on the coralline red algae Phymatolithon lusitanicum. We found that after 11 months of high CO2 exposure, photosynthesis increased with CO2 as opposed to respiration, which was positively affected by temperature. Results showed that this system is adequate to run long-term OA experiments and can be easily adapted to test other relevant variables simultaneously with CO2, such as temperature, irradiance and nutrients. PMID:27703853

Spatial and temporal analysis of Air Pollution Index and its timescale-dependent relationship with meteorological factors in Guangzhou, China, 2001-2011.

PubMed

Li, Li; Qian, Jun; Ou, Chun-Quan; Zhou, Ying-Xue; Guo, Cui; Guo, Yuming

2014-07-01

There is an increasing interest in spatial and temporal variation of air pollution and its association with weather conditions. We presented the spatial and temporal variation of Air Pollution Index (API) and examined the associations between API and meteorological factors during 2001-2011 in Guangzhou, China. A Seasonal-Trend Decomposition Procedure Based on Loess (STL) was used to decompose API. Wavelet analyses were performed to examine the relationships between API and several meteorological factors. Air quality has improved since 2005. APIs were highly correlated among five monitoring stations, and there were substantial temporal variations. Timescale-dependent relationships were found between API and a variety of meteorological factors. Temperature, relative humidity, precipitation and wind speed were negatively correlated with API, while diurnal temperature range and atmospheric pressure were positively correlated with API in the annual cycle. Our findings should be taken into account when determining air quality forecasts and pollution control measures. Copyright © 2014 Elsevier Ltd. All rights reserved.

Two-way effect modifications of air pollution and air temperature on total natural and cardiovascular mortality in eight European urban areas.

PubMed

Chen, Kai; Wolf, Kathrin; Breitner, Susanne; Gasparrini, Antonio; Stafoggia, Massimo; Samoli, Evangelia; Andersen, Zorana Jovanovic; Bero-Bedada, Getahun; Bellander, Tom; Hennig, Frauke; Jacquemin, Bénédicte; Pekkanen, Juha; Hampel, Regina; Cyrys, Josef; Peters, Annette; Schneider, Alexandra

2018-07-01

Although epidemiological studies have reported associations between mortality and both ambient air pollution and air temperature, it remains uncertain whether the mortality effects of air pollution are modified by temperature and vice versa. Moreover, little is known on the interactions between ultrafine particles (diameter ≤ 100 nm, UFP) and temperature. We investigated whether the short-term associations of particle number concentration (PNC in the ultrafine range (≤100 nm) or total PNC ≤ 3000 nm, as a proxy for UFP), particulate matter ≤ 2.5 μm (PM 2.5 ) and ≤ 10 μm (PM 10 ), and ozone with daily total natural and cardiovascular mortality were modified by air temperature and whether air pollution levels affected the temperature-mortality associations in eight European urban areas during 1999-2013. We first analyzed air temperature-stratified associations between air pollution and total natural (nonaccidental) and cardiovascular mortality as well as air pollution-stratified temperature-mortality associations using city-specific over-dispersed Poisson additive models with a distributed lag nonlinear temperature term in each city. All models were adjusted for long-term and seasonal trend, day of the week, influenza epidemics, and population dynamics due to summer vacation and holidays. City-specific effect estimates were then pooled using random-effects meta-analysis. Pooled associations between air pollutants and total and cardiovascular mortality were overall positive and generally stronger at high relatively compared to low air temperatures. For example, on days with high air temperatures (>75th percentile), an increase of 10,000 particles/cm 3 in PNC corresponded to a 2.51% (95% CI: 0.39%, 4.67%) increase in cardiovascular mortality, which was significantly higher than that on days with low air temperatures (<25th percentile) [-0.18% (95% CI: -0.97%, 0.62%)]. On days with high air pollution (>50th percentile), both heat- and cold-related mortality risks increased. Our findings showed that high temperature could modify the effects of air pollution on daily mortality and high air pollution might enhance the air temperature effects. Copyright © 2018 Elsevier Ltd. All rights reserved.

Correction of Temperatures of Air-Cooled Engine Cylinders for Variation in Engine and Cooling Conditions

NASA Technical Reports Server (NTRS)

Schey, Oscar W; Pinkel, Benjamin; Ellerbrock, Herman H , Jr

1939-01-01

Factors are obtained from semiempirical equations for correcting engine-cylinder temperatures for variation in important engine and cooling conditions. The variation of engine temperatures with atmospheric temperature is treated in detail, and correction factors are obtained for various flight and test conditions, such as climb at constant indicated air speed, level flight, ground running, take-off, constant speed of cooling air, and constant mass flow of cooling air. Seven conventional air-cooled engine cylinders enclosed in jackets and cooled by a blower were tested to determine the effect of cooling-air temperature and carburetor-air temperature on cylinder temperatures. The cooling air temperature was varied from approximately 80 degrees F. to 230 degrees F. and the carburetor-air temperature from approximately 40 degrees F. to 160 degrees F. Tests were made over a large range of engine speeds, brake mean effective pressures, and pressure drops across the cylinder. The correction factors obtained experimentally are compared with those obtained from the semiempirical equations and a fair agreement is noted.

Air regenerating and conditioning

NASA Technical Reports Server (NTRS)

Grishayenkov, B. G.

1975-01-01

Various physicochemical methods of regenerating and conditioning air for spacecraft are described with emphasis on conditions which affect efficiency of the system. Life support systems used in closed, hermetically sealed environments are discussed with references to actual application in the Soviet Soyuz and Voskhod manned spacecraft. Temperature and humidity control, removal of carbon dioxide, oxygen regeneration, and removal of bacteria and viruses are among the factors considered.

Nectar yeasts warm the flowers of a winter-blooming plant

PubMed Central

Herrera, Carlos M.; Pozo, María I.

2010-01-01

Yeasts are ubiquitous in terrestrial and aquatic microbiota, yet their ecological functionality remains relatively unexplored in comparison with other micro-organisms. This paper formulates and tests the novel hypothesis that heat produced by the sugar catabolism of yeast populations inhabiting floral nectar can increase the temperature of floral nectar and, more generally, modify the within-flower thermal microenvironment. Two field experiments were designed to test this hypothesis for the winter-blooming herb Helleborus foetidus (Ranunculaceae). In experiment 1, the effect of yeasts on the within-flower thermal environment was tested by excluding them from flowers, while in experiment 2 the test involved artificial inoculation of virgin flowers with yeasts. Nectary temperature (Tnect), within-flower air temperature (Tflow) and external air temperature (Tair) were measured on experimental and control flowers in both experiments. Experimental exclusion of yeasts from the nectaries significantly reduced, and experimental addition of yeasts significantly increased, the temperature excess of nectaries (ΔTnect = Tnect − Tair) and the air space inside flowers in relation to the air just outside the flowers. In non-experimental flowers exposed to natural pollinator visitation, ΔTnect was linearly related to log yeast cell density in nectar, and reached +6°C in nectaries with the densest yeast populations. The warming effect of nectar-dwelling yeasts documented in this study suggests novel ecological mechanisms potentially linking nectarivorous microbes with winter-blooming plants and their insect pollinators. PMID:20147331

Effects of Temperature and Air Density Profiles on Ozone Lidar Retrievals

NASA Astrophysics Data System (ADS)

Kirgis, G.; Langford, A. O.; Senff, C. J.; Alvarez, R. J. _II, II

2017-12-01

The recent reduction in the primary U.S. National Ambient Air Quality Standard (NAAQS) for ozone (O3) from 75 to 70 parts-per-billion by volume (ppbv) adds urgency to the need for better understanding of the processes that control ground-level concentrations in the United States. While ground-based in situ sensors are capable of measuring ozone levels, they don't give any insight into upper air transport and mixing. Differential absorption lidars such as the NOAA/ESRL Tunable Optical Profiler for Aerosol and oZone (TOPAZ) measure continuous vertical ozone profiles with high spatial and temporal resolution. However, the retrieved ozone mixing ratios depend on the temperature and air density profiles used in the analysis. This study analyzes the ozone concentrations for seven field campaigns from 2013 to 2016 to evaluate the impact of the assumed pressure and temperature profiles on the ozone mixing ratio retrieval. Pressure and temperature profiles from various spatial and temporal resolution models (Modern Era Retrospective-Analysis for Research and Applications, NCEP/NCAR Reanalysis, NCEP North American Regional Reanalysis, Rapid Refresh, and High-Resolution Rapid Refresh) are compared to reference ozone profiles created with pressure and temperature profiles from ozonesondes launched close to the TOPAZ measurement site. The results show significant biases with respect to time of day and season, altitude, and location of the model-extracted profiles. Limitations and advantages of all datasets used will also be discussed.

The relation between temperature distribution for lung RFA and electromagnetic wave frequency dependence of electrical conductivity with changing a lung's internal air volumes.

PubMed

Yamazaki, Nozomu; Watanabe, Hiroki; Lu, Xiaowei; Isobe, Yosuke; Kobayashi, Yo; Miyashita, Tomoyuki; Fujie, Masakatsu G

2013-01-01

Radio frequency ablation (RFA) for lung cancer has increasingly been used over the past few years because it is a minimally invasive treatment. As a feature of RFA for lung cancer, lung contains air during operation. Air is low thermal and electrical conductivity. Therefore, RFA for this cancer has the advantage that only the cancer is coagulated, and it is difficult for operators to control the precise formation of coagulation lesion. In order to overcome this limitation, we previously proposed a model-based robotic ablation system using finite element method. Creating an accurate thermo physical model and constructing thermal control method were a challenging problem because the thermal properties of the organ are complex. In this study, we measured electromagnetic wave frequency dependence of lung's electrical conductivity that was based on lung's internal air volumes dependence with in vitro experiment. In addition, we validated the electromagnetic wave frequency dependence of lung's electrical conductivity using temperature distribution simulator. From the results of this study, it is confirmed that the electromagnetic wave frequency dependence of lung's electrical conductivity effects on heat generation of RFA.

Body temperature and resistance to evaporative water loss in tropical Australian frogs.

PubMed

Tracy, Christopher R; Christian, Keith A; Betts, Gregory; Tracy, C Richard

2008-06-01

Although the skin of most amphibians measured to date offers no resistance to evaporative water loss (EWL), some species, primarily arboreal frogs, produce skin secretions that increase resistance to EWL. At high air temperatures, it may be advantageous for amphibians to increase EWL as a means to decrease body temperature. In Australian hylid frogs, most species do not decrease their resistance at high air temperature, but some species with moderate resistance (at moderate air temperatures) gradually decrease resistance with increasing air temperature, and some species with high resistance (at moderate air temperatures) abruptly decrease resistance at high air temperatures. Lower skin resistance at high air temperatures decreases the time to desiccation, but the lower body temperatures allow the species to avoid their critical thermal maximum (CT(Max)) body temperatures. The body temperatures of species with low to moderate resistances to EWL that do not adjust resistance at high air temperatures do not warm to their CT(Max), although for some species, this is because they have high CT(Max) values. As has been reported previously for resistance to EWL generally, the response pattern of change of EWL at high air temperatures has apparently evolved independently among Australian hylids. The mechanisms involved in causing resistance and changes in resistance are unknown.

Implementation of Temperature Sequential Controller on Variable Speed Drive

NASA Astrophysics Data System (ADS)

Cheong, Z. X.; Barsoum, N. N.

2008-10-01

There are many pump and motor installations with quite extensive speed variation, such as Sago conveyor, heating, ventilation and air conditioning (HVAC) and water pumping system. A common solution for these applications is to run several fixed speed motors in parallel, with flow control accomplish by turning the motors on and off. This type of control method causes high in-rush current, and adds a risk of damage caused by pressure transients. This paper explains the design and implementation of a temperature speed control system for use in industrial and commercial sectors. Advanced temperature speed control can be achieved by using ABB ACS800 variable speed drive-direct torque sequential control macro, programmable logic controller and temperature transmitter. The principle of direct torque sequential control macro (DTC-SC) is based on the control of torque and flux utilizing the stator flux field orientation over seven preset constant speed. As a result of continuous comparison of ambient temperature to the references temperatures; electromagnetic torque response is particularly fast to the motor state and it is able maintain constant speeds. Experimental tests have been carried out by using ABB ACS800-U1-0003-2, to validate the effectiveness and dynamic respond of ABB ACS800 against temperature variation, loads, and mechanical shocks.

Design and development of the Waukesha Custom Engine Control Air/Fuel Module

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

Moss, D.W.

1996-12-31

The Waukesha Custom Engine Control Air/Fuel Module (AFM) is designed to control the air-fuel ratio for all Waukesha carbureted, gaseous fueled, industrial engine. The AFM is programmed with a personal computer to run in one of four control modes: catalyst, best power, best economy, or lean-burn. One system can control naturally aspirated, turbocharged, in-line or vee engines. The basic system consists of an oxygen sensing system, intake manifold pressure transducer, electronic control module, actuator and exhaust thermocouple. The system permits correct operation of Waukesha engines in spite of changes in fuel pressure or temperature, engine load or speed, and fuelmore » composition. The system utilizes closed loop control and is centered about oxygen sensing technology. An innovative approach to applying oxygen sensors to industrial engines provides very good performance, greatly prolongs sensor life, and maintains sensor accuracy. Design considerations and operating results are given for application of the system to stationary, industrial engines operating on fuel gases of greatly varying composition.« less

Utilization of ultrasonic atomization for dust control in underground mining

NASA Astrophysics Data System (ADS)

Okawa, Hirokazu; Nishi, Kentaro; Kawamura, Youhei; Kato, Takahiro; Sugawara, Katsuyasu

2017-07-01

This study examined dust suppression using water particles generated by ultrasonic atomization (2.4 MHz) at low temperature (10 °C). Green tuff (4 µm), green tuff (6 µm), kaolin, and silica were used as dust samples. Even though ultrasonic atomization makes fine water particles, raising relative air humidity immediately was difficult at low temperature. However, remaining water particles that did not change to water vapor contributed to suppression of dust dispersion. Additionally, the effect of water vapor amount (absolute humidity) and water particles generated by ultrasonic atomization on the amount of dust dispersion was investigated using experimental data at temperatures of 10, 20, and 30 °C. Utilization of ultrasound atomization at low temperature has the advantages of low humidity increments in the working space and water particles remaining stable even with low relative air humidity.

Recovery of valuable metals from waste diamond cutters through ammonia-ammonium sulfate leaching

NASA Astrophysics Data System (ADS)

Xue, Ping; Li, Guang-qiang; Yang, Yong-xiang; Qin, Qin-wei; Wei, Ming-xing

2017-12-01

Copper and zinc were recovered from waste diamond cutters through leaching with an ammonia-ammonium sulfate system and air as an oxidant. The effects of experimental parameters on the leaching process were investigated, and the potential-pH ( E-pH) diagrams of Cu-NH3-SO4 2--H2O and Zn-NH3-SO4 2--H2O at 25°C were drawn. Results showed that the optimal parameters for the leaching reaction are as follows: reaction temperature, 45°C; leaching duration, 3 h; liquid-to-solid ratio, 50:1 (mL/g); stirring speed, 200 r/min; ammonia concentration, 4.0 mol/L; ammonium sulfate concentration, 1.0 mol/L; and air flow rate, 0.2 L/min. The results of the kinetics study indicated that the leaching is controlled by the surface chemical reaction at temperatures below 35°C, and the leaching is controlled by diffusion through the product layer at temperatures above 35°C.

Field and Laboratory Measurements of Carbon Dioxide Mixing Ratios in Air Using the LI-COR LI-7000 CO2/H2O Analyzer

NASA Astrophysics Data System (ADS)

Murphy, P. C.; Lerner, B. M.; Williams, E. J.

2003-12-01

Air measurements of CO2 were made with a LI-COR LI-7000 CO2/H2O analyzer on the NOAA ship Ronald H. Brown during the New England Air Quality Study (NEAQS 2002) field campaign. This instrument is an improved version of the older model LI-6262 CO2/H2O analyzer, which uses a non-dispersive IR radiation absorption technique. During NEAQS, we operated the LI-7000 without temperature regulation, using a simple 2-point calibration scheme. An intercomparison between our measurements of atmospheric CO2 mixing ratios and those measured by a more sophisticated method, using temperature-regulation and a multipoint calibration with a LI-6252 CO2 analyzer (operated by AOML) shows generally good results ([CO2]AL = [CO2]AOML x 1.015 (0.010) - 5.7 (3.8) ppmv; R2 = 0.9889) in highly variable air masses. During subsequent laboratory studies, we evaluated the instrument for the manufacturer's claims of improvement in signal noise, sample gas temperature equilibration and zero drift with temperature. Further work examined the instrument's susceptibility to rapid temperature changes, which has been previously demonstrated to introduce error of several ppmv ° C-1 in the LI-6252. A change in the LI-7000 optical bench temperature of 12 ° C in 1 hour caused a sampling error of ˜3 ppmv CO2. Therefore, our lab investigations indicate that the LI-7000 would benefit from a temperature-controlled enclosure, as is used by the AOML group.

Biophysical control of leaf temperature

NASA Astrophysics Data System (ADS)

Dong, N.; Prentice, I. C.; Wright, I. J.

2014-12-01

In principle sunlit leaves can maintain their temperatures within a narrower range than ambient temperatures. This is an important and long-known (but now overlooked) prediction of energy balance theory. Net radiation at leaf surface in steady state (which is reached rapidly) must be equal to the combination of sensible and latent heat exchanges with surrounding air, the former being proportional to leaf-to-air temperature difference (ΔT), the latter to the transpiration rate. We present field measurements of ΔT which confirm the existence of a 'crossover temperature' in the 25-30˚C range for species in a tropical savanna and a tropical rainforest environment. This finding is consistent with a simple representation of transpiration as a function of net radiation and temperature (Priestley-Taylor relationship) assuming an entrainment factor (ω) somewhat greater than the canonical value of 0.26. The fact that leaves in tropical forests are typically cooler than surrounding air, often already by solar noon, is consistent with a recently published comparison of MODIS day-time land-surface temperatures with air temperatures. Theory further predicts a strong dependence of leaf size (which is inversely related to leaf boundary-layer conductance, and therefore to absolute magnitude of ΔT) on moisture availability. Theoretically, leaf size should be determined by either night-time constraints (risk of frost damage to active leaves) or day-time constraints (risk of heat stress damage),with the former likely to predominate - thereby restricting the occurrence of large leaves - at high latitudes. In low latitudes, daytime maximum leaf size is predicted to increase with temperature, provided that water is plentiful. If water is restricted, however, transpiration cannot proceed at the Priestley-Taylor rate, and it quickly becomes advantageous for plants to have small leaves, which do not heat up much above the temperature of their surroundings. The difference between leaf and air temperature is generally neglected in terrestrial ecosystem and carbon cycle models. This is a significant omission that could lead to an over-estimation of the heat-stress vulnerability of carbon uptake in the wet tropics. Leaf energy balance theory is well established, and should be included in the next generation of models.

Does air gas aesthesiometry generate a true mechanical stimulus for corneal sensitivity measurement?

PubMed

Nosch, Daniela S; Pult, Heiko; Albon, Julie; Purslow, Christine; Murphy, Paul J

2018-03-01

Belmonte Ocular Pain Meter (OPM) air jet aesthesiometry overcomes some of the limitations of the Cochet-Bonnet aesthesiometer. However, for true mechanical corneal sensitivity measurement, the airflow stimulus temperature of the aesthesiometer must equal ocular surface temperature (OST), to avoid additional response from temperature-sensitive nerves. The aim of this study was to determine: (A) the stimulus temperature inducing no or least change in OST; and (B) to evaluate if OST remains unchanged with different stimulus durations and airflow rates. A total of 14 subjects (mean age 25.14 ± 2.18 years; seven women) participated in this clinical cohort study: (A) OST was recorded using an infrared camera (FLIR A310) during the presentation of airflow stimuli, at five temperatures, ambient temperature (AT) +5°C, +10°C, +15°C, +20°C and +30°C, using the OPM aesthesiometer (duration three seconds; over a four millimetre distance; airflow rate 60 ml/min); and (B) OST measurements were repeated with two stimulus temperatures (AT +10°C and +15°C) while varying stimulus durations (three seconds and five seconds) and airflow rates (30, 60, 80 and 100 ml/min). Inclusion criteria were age <40 years, no contact lens wear, absence of ocular disease including dry eye, and no use of artificial tears. Repeated measures (analysis of variance) and appropriate post-hoc t-tests were applied. (A) Stimulus temperatures of AT +10°C and +15°C induced the least changes in OST (-0.20 ± 0.13°C and 0.08 ± 0.05°C). (B) OST changes were statistically significant with both stimulus temperatures and increased with increasing airflow rates (p < 0.001), and were more marked with stimulus temperature AT +10°C. A true mechanical threshold for corneal sensitivity cannot be established with the air stimulus of the Belmonte OPM because its air jet stimulus with mechanical setting is likely to have a thermal component. Appropriate stimulus selection for an air jet aesthesiometer must incorporate stimulus temperature control that can vary with stimulus duration and airflow rate. © 2017 Optometry Australia.

Comparison of MODIS Land Surface Temperature and Air Temperature over the Continental USA Meteorological Stations

NASA Technical Reports Server (NTRS)

Zhang, Ping; Bounoua, Lahouari; Imhoff, Marc L.; Wolfe, Robert E.; Thome, Kurtis

2014-01-01

The National Land Cover Database (NLCD) Impervious Surface Area (ISA) and MODIS Land Surface Temperature (LST) are used in a spatial analysis to assess the surface-temperature-based urban heat island's (UHIS) signature on LST amplitude over the continental USA and to make comparisons to local air temperatures. Air-temperature-based UHIs (UHIA), calculated using the Global Historical Climatology Network (GHCN) daily air temperatures, are compared with UHIS for urban areas in different biomes during different seasons. NLCD ISA is used to define urban and rural temperatures and to stratify the sampling for LST and air temperatures. We find that the MODIS LST agrees well with observed air temperature during the nighttime, but tends to overestimate it during the daytime, especially during summer and in nonforested areas. The minimum air temperature analyses show that UHIs in forests have an average UHIA of 1 C during the summer. The UHIS, calculated from nighttime LST, has similar magnitude of 1-2 C. By contrast, the LSTs show a midday summer UHIS of 3-4 C for cities in forests, whereas the average summer UHIA calculated from maximum air temperature is close to 0 C. In addition, the LSTs and air temperatures difference between 2006 and 2011 are in agreement, albeit with different magnitude.

Control of Penicillium martensii Development and Penicillic Acid Production by Atmospheric Gases and Temperatures

PubMed Central

Lillehoj, E. B.; Milburn, M. S.; Ciegler, A.

1972-01-01

The effects of various gaseous environments and temperatures on development of Penicillium martensii NRRL 3612 and production of penicillic acid (PA) were determined. Accumulation of PA in mold-inoculated corn was measured following incubation under air; 20% CO2, 20% O2, 60% N2; 40% CO2, 20% O2, 40% N2; and 60% CO2, 20% O2, 20% N2. Although reduced temperature initially inhibited PA production, at the end of the trial the largest quantity of PA (120 μg/g of corn) was found in air-incubated corn at the lowest test temperature (5 C). Atmospheres enriched with 60% CO2 reduced PA accumulation below a detectable level at 5 and 10 C after a 4-week incubation period. Spore germination tests were carried out in a liquid growth medium incubated for 16 hr under several test conditions. Germ tube outgrowth at 30 C ranged from 36% in air to 2% in 60% CO2, whereas no germination was observed in CO2-enriched gases at 10 C. When spore respiration rates were measured in air and O2 in a liquid growth medium, complete removal of CO2 from the reaction atmosphere did not reduce O2 uptake. PMID:5071649

Retrieval of air temperatures from crowd-sourced battery temperatures of cell phones

NASA Astrophysics Data System (ADS)

Overeem, Aart; Robinson, James; Leijnse, Hidde; Uijlenhoet, Remko; Steeneveld, Gert-Jan; Horn, Berthold K. P.

2013-04-01

Accurate air temperature observations are important for urban meteorology, for example to study the urban heat island and adverse effects of high temperatures on human health. The number of available temperature observations is often relatively limited. A new development is presented to derive temperature information for the urban canopy from an alternative source: cell phones. Battery temperature data were collected by users of an Android application for cell phones (opensignal.com). The application automatically sends battery temperature data to a server for storage. In this study, battery temperatures are averaged in space and time to obtain daily averaged battery temperatures for each city separately. A regression model, which can be related to a physical model, is employed to retrieve daily air temperatures from battery temperatures. The model is calibrated with observed air temperatures from a meteorological station of an airport located in or near the city. Time series of air temperatures are obtained for each city for a period of several months, where 50% of the data is for independent verification. Results are presented for Buenos Aires, London, Los Angeles, Paris, Mexico City, Moscow, Rome, and Sao Paulo. The evolution of the retrieved air temperatures often correspond well with the observed ones. The mean absolute error of daily air temperatures is less than 2 degrees Celsius, and the bias is within 1 degree Celsius. This shows that monitoring air temperatures employing an Android application holds great promise. Since 75% of the world's population has a cell phone, 20% of the land surface of the earth has cellular telephone coverage, and 500 million devices use the Android operating system, there is a huge potential for measuring air temperatures employing cell phones. This could eventually lead to real-time world-wide temperature maps.

Effects of open-air temperature on air temperature inside biological safety cabinet.

PubMed

Umemura, Masayuki; Shigeno, Katsuro; Yamamura, Keiko; Osada, Takashi; Soda, Midori; Yamada, Kiyofumi; Ando, Yuichi; Wakiya, Yoshifumi

2011-02-14

In Japan, biological safety cabinets (BSCs) are normally used by medical staff while handling antineoplastic agents. We have also set up a class II B2 BSC at the Division of Chemotherapy for Outpatients. The air temperature inside this BSC, however, decreases in winter. We assumed that this decrease is caused by the intake of open-air. Therefore, we investigated the effects of low open-air temperature on the BSC temperature and the time of admixtures of antineoplastic agents. The studies were conducted from January 1 to March 31, 2008. The outdoor air temperature was measured in the shade near the intake nozzle of the BSC and was compared with the BSC temperature. The correlation between the outdoor air temperature and the BSC temperature, the dissolution time of cyclophosphamide (CPA) and gemcitabine (GEM), and accurate weight measurement of epirubicin (EPI) solution were investigated for low and normal BSC temperatures. The BSC temperature was correlated with the open-air temperature for open-air temperatures of 5-20°C (p < 0.0001). The dissolution of CPA and GEM at these temperatures was significantly delayed as compared to that at 25°C (p < 0.01 and p < 0.0001, respectively). The weight measurement of EPI solution using a syringe method lacks accuracy because of its high coefficient of viscosity at low temperatures (p < 0.01). These results suggest that the BSC temperature decreases below room temperature in winter when air is drawn from outdoors. We showed that the BSC temperature affects the dissolution rate of antineoplastic agents. Further, we suggested that the BSC temperature drop might delay the affair of the admixtures of antineoplastic agents and increase the waiting time of outpatients for chemotherapy.

Daily Cycle of Air Temperature and Surface Temperature in Stone Forest

NASA Astrophysics Data System (ADS)

Wang, K.; Li, Y.; Wang, X.; Yuan, M.

2013-12-01

Urbanization is one of the most profound human activities that impact on climate change. In cities, where are highly artificial areas, the conflict between human activity and natural climate is particularly prominent. Urban areas always have the larger area of impervious land, the higher consumption of greenhouse gases, more emissions of anthropogenic heat and air pollution, all contribute to the urban warming phenomena. Understanding the mechanisms causing a variety of phenomena involved in the urban warming is critical to distinguish the anthropogenic effect and natural variation in the climate change. However, the exact dynamics of urban warming were poorly understood, and effective control strategies are not available. Here we present a study of the daily cycle of air temperature and surface temperature in Stone Forest. The specific heat of the stones in the Stone Forest and concrete of the man-made structures within the cities are approximate. Besides, the height of the Stone Forest and the height of buildings within the city are also similar. As a scenic area, the Stone Forest is being preserved and only opened for sightseeing. There is no anthropogenic heat, as well air pollution within the Stone Forest. The thermal environment in Stone Forest can be considered to be a simulation of thermal environment in the city, which can reveal the effect of man-made structures on urban thermal environment. We conducted the field studies and numerical analysis in the Stone Forest for 4 typical urban morphology and environment scenarios, including high-rise compact cities, low-rise sparse cities, garden cities and isolated single stone. Air temperature and relative humidity were measured every half an hour in 15 different locations, which within different spatial distribution of stones and can represent the four urban scenarios respectively. At the same time, an infrared camera was used to take thermal images and get the hourly surface temperatures of stones and vegetation in the measurement area. The differences of the daily cycle of air temperature and surface temperature in these four scenarios show a significant impact of urban man-made structures on the dynamics of urban thermal environment.

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.

Subsurface dynamics of reactive and inert gases in the context of noble gases as environmental tracers in groundwater hydrology

NASA Astrophysics Data System (ADS)

Mayer, Simon; Jenner, Florian; Aeschbach, Werner

2017-04-01

Applications of inert gases in groundwater hydrology require a profound understanding of underlying biogeochemical processes. Some of these processes are, however, not well understood and therefore require further investigation. This is the first study simultaneously investigating soil air and groundwater in the context of noble gas tracer applications, accounting for seasonal effects in different climate regions. The sampled data confirm a general reliability of common assumptions proposed in the literature. In particular, a solubility-controlled description of excess air formation and of groundwater degassing can be confirmed. This study identifies certain effects which need to be taken into account to reliably evaluate noble gas patterns. First, long-term samplings suggest a permanent temperature-driven equilibration of shallow groundwater with entrapped air bubbles, even some years after recharge. Second, minor groundwater degassing is found to challenge existing excess air model approaches, depending on the amount and the fractionation of excess air. Third, soil air composition data of this study imply a potential bias of noble gas temperatures by up to about 2℃ due to microbial oxygen depletion and a reduced sum value of O2+CO2. This effect causes systematically lower noble gas temperatures in tropical groundwater samples and in shallow mid-latitude groundwater samples after strong recharge during the warm season. However, a general bias of noble gas temperatures in mid-latitudes is probably prevented by a predominant recharge during the cold season, accompanied by nearly atmospheric noble gas mixing ratios in the soil air. Findings of this study provide a remarkable contribution to the reliability of noble gas tracer applications in hydrology, in particular with regard to paleoclimate reconstructions and an understanding of subsurface gas dynamics.

Analysis of Temperature Variability in Medication Storage Compartments in Emergency Transport Helicopters.

PubMed

O'Donnell, Margaret A; Whitfield, Justin

The purpose of this study was to determine whether the temperature in medication storage compartments in air medical helicopters was within United States Pharmacopeia (USP)-defined limits for controlled room temperature. This was a prospective study using data obtained from a continuous temperature monitoring device. A total of 4 monitors were placed within 2 medication storage locations in 2 identical helicopters. The data collection period lasted 2 weeks during the summer and winter seasons. Data retrieved from monitors were compared against USP parameters for proper medication storage. Results documented temperatures outside the acceptable range a majority of the time with temperatures above the high limit during summer and below the low limit during winter. The study determined that compartments used for medication storage frequently fell outside of the range for USP-defined limits for medication storage. Flight programs should monitor storage areas, carefully taking actions to keep medication within defined ranges. Copyright © 2016 Air Medical Journal Associates. Published by Elsevier Inc. All rights reserved.

Control of electrothermal heating during regeneration of activated carbon fiber cloth.

PubMed

Johnsen, David L; Mallouk, Kaitlin E; Rood, Mark J

2011-01-15

Electrothermal swing adsorption (ESA) of organic gases generated by industrial processes can reduce atmospheric emissions and allow for reuse of recovered product. Desorption energy efficiency can be improved through control of adsorbent heating, allowing for cost-effective separation and concentration of these gases for reuse. ESA experiments with an air stream containing 2000 ppm(v) isobutane and activated carbon fiber cloth (ACFC) were performed to evaluate regeneration energy consumption. Control logic based on temperature feedback achieved select temperature and power profiles during regeneration cycles while maintaining the ACFC's mean regeneration temperature (200 °C). Energy requirements for regeneration were independent of differences in temperature/power oscillations (1186-1237 kJ/mol of isobutane). ACFC was also heated to a ramped set-point, and the average absolute error between the actual and set-point temperatures was small (0.73%), demonstrating stable control as set-point temperatures vary, which is necessary for practical applications (e.g., higher temperatures for higher boiling point gases). Additional logic that increased the maximum power application at lower ACFC temperatures resulted in a 36% decrease in energy consumption. Implementing such control logic improves energy efficiency for separating and concentrating organic gases for post-desorption liquefaction of the organic gas for reuse.

Effects of air temperature and discharge on Upper Mississippi River summer water temperatures

USGS Publications Warehouse

Gray, Brian R.; Robertson, Dale M.; Rogala, James T.

2018-01-01

Recent interest in the potential effects of climate change has prompted studies of air temperature and precipitation associations with water temperatures in rivers and streams. We examined associations between summer surface water temperatures and both air temperature and discharge for 5 reaches of the Upper Mississippi River during 1994–2011. Water–air temperature associations at a given reach approximated 1:1 when estimated under an assumption of reach independence but declined to approximately 1:2 when water temperatures were permitted to covary among reaches and were also adjusted for upstream air temperatures. Estimated water temperature–discharge associations were weak. An apparently novel feature of this study is that of addressing changes in associations between water and air temperatures when both are correlated among reaches.

Control of temperature and aqueous Mg2+/Ca2+ ratio on the (trans-)formation of ikaite

NASA Astrophysics Data System (ADS)

Purgstaller, B.; Dietzel, M.; Baldermann, A.; Mavromatis, V.

2017-11-01

The calcium carbonate hexahydrate mineral ikaite (CaCO3 ṡ 6 H2O) has been documented in aquatic environments at near-freezing temperatures. An increase of the prevailing temperature in the depositional environment, results in the transformation of natural ikaite into less soluble calcium carbonate phases occasionally leaving calcite pseudomorphs in the sediments, which are considered as an indicator for primary cold water temperatures. Detailed understanding on the physicochemical parameters controlling ikaite (trans-)formation however, such as temperature and reactive solution chemical composition, are still under debate. In order to study the formation of ikaite, we conducted precipitation experiments under controlled physicochemical conditions (pH = 8.3 ± 0.1; T = 6, 12, and 18 ± 0.1 °C) at defined aqueous molar Mg/Ca ratios. The transformation of ikaite into anhydrous calcium carbonate polymorphs was investigated in solution and at air exposure. The obtained results reveal the formation of ikaite at temperatures up to 12 °C, whereas Mg-rich amorphous calcium carbonate precipitated at 18 °C. In contact with the reactive solution ikaite transformed into aragonite at aqueous molar Mg2+/Ca2+ ratios of ≥14. In contrast, ikaite separated from the Mg-rich solution and exposed to air transformed in all cases into calcite/vaterite. The herein obtained temperature limit of ≤12 for ikaite formation is significantly higher than formerly expected and most probably caused by (i) the high saturation degree of the solution with respect to ikaite and (ii) the slow dehydration of the aqueous Ca2+ ion at low temperatures. This result questions the suitability of calcite pseudomorphs (i.e. glendonites) as a proxy for near-freezing temperatures. Moreover, our findings show that the CaCO3 polymorph formed from ikaite is strongly controlled by the physicochemical conditions, such as aqueous molar Mg2+/Ca2+ ratio of the reactive fluid and H2O availability throughout the transformation process.

Effects of moisture controlled charcoal on indoor thermal and air environments

NASA Astrophysics Data System (ADS)

Matsumoto, Hiroshi; Yokogoshi, Midori; Nabeshima, Yuki

2017-10-01

It is crucial to remove and control indoor moisture in Japan, especially in hot and humid summers, in order to improve thermal comfort and save energy in buildings. Charcoal for moisture control made from the waste of wood material has attracted attention among many control strategies to control indoor moisture, and it is beginning to be used in houses. However, the basic characteristics of the charcoal to control moisture and remove chemical compounds in indoor air have not been investigated sufficiently. The objective of this study is to clarify the effect of moisture control charcoal on indoor thermal and air environments by a long-term field measurement using two housing scale models with/without charcoal in Toyohashi, Japan. The comparative experiments to investigate the effect of the charcoal on air temperature and humidity for two models with/without charcoal were conducted from 2015 to 2016. Also, the removal performance of volatile organic compound (VOCs) was investigated in the summer of 2015. Four bags of packed charcoal were set on the floor in the attic for one model during the experiment. As a result of the experiments, a significant effect of moisture control was observed in hot and humid season, and the efficient effect of moisture adsorption was obtained by the periodic humidification experiment using a humidifier. Furthermore, the charcoal showed a remarkable performance of VOC removal from indoor air by the injection experiment of formaldehyde.

Recommendations to Improve Employee Thermal Comfort When Working in 40°F Refrigerated Cold Rooms.

PubMed

Ceballos, Diana; Mead, Kenneth; Ramsey, Jessica

2015-01-01

Cold rooms are commonly used for food storage and preparation, and are usually kept around 40°F following food safety guidelines. Some food preparation employees may spend 8 or more hours inside cold rooms. These employees may not be aware of the risks associated with mildly cold temperatures, dampness, and limited ventilation. We performed an evaluation of cold rooms at an airline catering facility because of concerns with exposure to cold temperatures. We spoke with and observed employees in two cold rooms, reviewed daily temperature logs, evaluated employee's physical activity, work/rest schedule, and protective clothing. We measured temperature, percent relative humidity, and air velocities at different work stations inside the cold rooms. We concluded that thermal comfort concerns perceived by cold room employees may have been the result of air drafts at their workstations, insufficient use of personal protective equipment due to dexterity concerns, work practices, and lack of knowledge about good health and safety practices in cold rooms. These moderately cold work conditions with low air velocities are not well covered in current occupational health and safety guidelines, and wind chill calculations do not apply. We provide practical recommendations to improve thermal comfort of cold room employees. Engineering control recommendations include the redesigning of air deflectors and installing of suspended baffles. Administrative controls include the changing out of wet clothing, providing hand warmers outside of cold rooms, and educating employees on cold stress. We also recommended providing more options on personal protective equipment. However, there is a need for guidelines and educational materials tailored to employees in moderately cold environments to improve thermal comfort and minimize health and safety problems.

Recommendations to Improve Employee Thermal Comfort When Working in 40°F Refrigerated Cold Rooms

PubMed Central

Ceballos, Diana; Mead, Kenneth; Ramsey, Jessica

2015-01-01

Cold rooms are commonly used for food storage and preparation, and are usually kept around 40°F following food safety guidelines. Some food preparation employees may spend 8 or more hours inside cold rooms. These employees may not be aware of the risks associated with mildly cold temperatures, dampness, and limited ventilation. We performed an evaluation of cold rooms at an airline catering facility because of concerns with exposure to cold temperatures. We spoke with and observed employees in two cold rooms, reviewed daily temperature logs, evaluated employee’s physical activity, work/rest schedule, and protective clothing. We measured temperature, percent relative humidity, and air velocities at different work stations inside the cold rooms. We concluded that thermal comfort concerns perceived by cold room employees may have been the result of air drafts at their workstations, insufficient use of personal protective equipment due to dexterity concerns, work practices, and lack of knowledge about good health and safety practices in cold rooms. These moderately cold work conditions with low air velocities are not well covered in current occupational health and safety guidelines, and wind chill calculations do not apply. We provide practical recommendations to improve thermal comfort of cold room employees. Engineering control recommendations include the redesigning of air deflectors and installing of suspended baffles. Administrative controls include the changing out of wet clothing, providing hand warmers outside of cold rooms, and educating employees on cold stress. We also recommended providing more options on personal protective equipment. However, there is a need for guidelines and educational materials tailored to employees in moderately cold environments to improve thermal comfort and minimize health and safety problems. PMID:25961447

40 CFR 86.000-2 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

..., solar thermal load, ambient temperature, and humidity control or simulation which meets the requirements... while the vehicle's air conditioning system is operating, as described in § 86.160-00 over the SC03...

40 CFR 86.000-2 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-07-01

..., solar thermal load, ambient temperature, and humidity control or simulation which meets the requirements... while the vehicle's air conditioning system is operating, as described in § 86.160-00 over the SC03...

Laboratory Test of Reciprocating Internal Combustion Engines

DTIC Science & Technology

2016-02-04

testing require extremely accurate fuel consumption measurement, and the ability to temperature condition the fuel. Most dynamometer manufacturers...include, but are not limited to, differences in fuels, lubrication, temperatures , engine control module parameters, component wear, exhaust, and air...exhaust gas recirculation (EGR) fuel consumption 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT SAR 18. NUMBER OF PAGES 38

Predicting Canopy Temperatures without and with Infrared Heating of Open-Field Plots and Energy Requirements for such Infrared Heating

USDA-ARS?s Scientific Manuscript database

In order to determine the likely effect of global warming on agricultural productivity while avoiding experimental artifacts, there is a need to conduct warming research under conditions as representative as possible of future open fields, i.e., temperature free-air controlled enhancement (T-FACE) e...

Creep Behavior in Interlaminar Shear of a CVI SiC/SiC Composite at Elevated Temperatures in Air and Steam

DTIC Science & Technology

2012-03-22

upper use temperature under high tensile stress (allows long life , dimensional control, low residual CMC stress) Matrix Creep , Fiber Creep Long... creep life due to steam was more significant at 28%. However, at 22 MPa, the presence of steam appeared to be beneficial and extended creep

Trends and sensitivities of low streamflow extremes to discharge timing and magnitude in Pacific Northwest mountain streams

Treesearch

Patrick R. Kormos; Charlie Luce; Seth J. Wenger; Wouter R. Berghuijs

2016-01-01

Path analyses of historical streamflow data from the Pacific Northwest indicate that the precipitation amount has been the dominant control on the magnitude of low streamflow extremes compared to the air temperature-affected timing of snowmelt runoff. The relative sensitivities of low streamflow to precipitation and temperature changes have important...

Comparison of ground based indices (API and AQI) with satellite based aerosol products.

PubMed

Zheng, Sheng; Cao, Chun-Xiang; Singh, Ramesh P

2014-08-01

Air quality in mega cities is one of the major concerns due to serious health issues and its indirect impact to the climate. Among mega cities, Beijing city is considered as one of the densely populated cities with extremely poor air quality. The meteorological parameters (wind, surface temperature, air temperature and relative humidity) control the dynamics and dispersion of air pollution. China National Environmental Monitoring Centre (CNEMC) started air pollution index (API) as of 2000 to evaluate air quality, but over the years, it was felt that the air quality is not well represented by API. Recently, the Ministry of Environmental Protection (MEP) of the People's Republic of China (PRC) started using a new index "air quality index (AQI)" from January 2013. We have compared API and AQI with three different MODIS (MODIS - Moderate Resolution Imaging SpectroRadiometer, onboard the Terra/Aqua satellites) AOD (aerosol optical depth) products for ten months, January-October, 2013. The correlation between AQI and Aqua Deep Blue AOD was found to be reasonably good as compared with API, mainly due to inclusion of PM2.5 in the calculation of AQI. In addition, for every month, the correlation coefficient between AQI and Aqua Deep Blue AOD was found to be relatively higher in the month of February to May. According to the monthly average distribution of precipitation, temperature, and PM10, the air quality in the months of June-September was better as compared to those in the months of February-May. AQI and Aqua Deep Blue AOD show highly polluted days associated with dust event, representing true air quality of Beijing. Copyright © 2013 Elsevier B.V. All rights reserved.

High Lapse Rates in AIRS Retrieved Temperatures in Cold Air Outbreaks

NASA Technical Reports Server (NTRS)

Fetzer, Eric J.; Kahn, Brian; Olsen, Edward T.; Fishbein, Evan

2004-01-01

The Atmospheric Infrared Sounder (AIRS) experiment, on NASA's Aqua spacecraft, uses a combination of infrared and microwave observations to retrieve cloud and surface properties, plus temperature and water vapor profiles comparable to radiosondes throughout the troposphere, for cloud cover up to 70%. The high spectral resolution of AIRS provides sensitivity to important information about the near-surface atmosphere and underlying surface. A preliminary analysis of AIRS temperature retrievals taken during January 2003 reveals extensive areas of superadiabatic lapse rates in the lowest kilometer of the atmosphere. These areas are found predominantly east of North America over the Gulf Stream, and, off East Asia over the Kuroshio Current. Accompanying the high lapse rates are low air temperatures, large sea-air temperature differences, and low relative humidities. Imagery from a Visible / Near Infrared instrument on the AIRS experiment shows accompanying clouds. These lines of evidence all point to shallow convection in the bottom layer of a cold air mass overlying warm water, with overturning driven by heat flow from ocean to atmosphere. An examination of operational radiosondes at six coastal stations in Japan shows AIRS to be oversensitive to lower tropospheric lapse rates due to systematically warm near-surface air temperatures. The bias in near-surface air temperature is seen to be independent of sea surface temperature, however. AIRS is therefore sensitive to air-sea temperature difference, but with a warm atmospheric bias. A regression fit to radiosondes is used to correct AIRS near-surface retrieved temperatures, and thereby obtain an estimate of the true atmosphere-ocean thermal contrast in five subtropical regions across the north Pacific. Moving eastward, we show a systematic shift in this air-sea temperature differences toward more isothermal conditions. These results, while preliminary, have implications for our understanding of heat flow from ocean to atmosphere. We anticipate future improvements in the AIRS retrieval algorithm will lead to improved understanding of the exchange of sensible and latent heat from ocean to atmosphere, and more realistic near-surface lapse rates.

Reaction of wood radius of multiple tree species to changing environmental conditions

NASA Astrophysics Data System (ADS)

Merganicova, Katarina; Merganic, Jan; Sitkova, Zuzana; Lestianska, Adriana; Strelcova, Katarina; Valent, Peter; Jezik, Marek

2017-04-01

Dendrometers are frequently used to study the radial dynamics of forest trees. Since the fluctuations of tree stem radius are caused by multiple factors including changes in tree water status and the actual tree growth, the methods used to derive the radial growth from dendrometer data provide us with the estimates of diurnal radial increments rather than their precise values. In addition, dendrometers react to environmental conditions themselves, which can in some cases cause misinterpretation of measured values. In the presented study we aimed at analysing the reaction of band dendrometers and wood radius of 7 different tree species on changing environmental conditions. The data come from a controlled experiment performed in the climate chambers, in which we placed 5 stand-alone dendrometers and 30 wooden pieces representing 7 different tree species equipped with band dendrometers. Air temperature and air humidity were controlled inside the chambers and their impact on wood radius and dendrometers was analysed. The results showed that both wooden pieces and dendrometers reacted to changes in air temperature and air humidity, while the reaction was species specific and dependent on the actual water status of wooden pieces. The overall trend of measured radial changes of wooden pieces followed the changes in temperature, i.e. the increase in temperature caused the increase in the measured radii. The change in air humidity explained less than 50% of the variation in radial measurements. The obtained results indicate that although the band dendrometers applied in the study were able to measure values with the precision of one micrometre, the differences between the measurements of up to ten micrometres need not represent the actual changes in stem radius, but may only reflect the reactions of the instrument to surrounding conditions. Hence, the measurements by dendrometers must always be examined thoroughly with regard to all the multiple effects before any conclusions based on them are stated.

A Low-Power Thermal-Based Sensor System for Low Air Flow Detection

PubMed Central

Arifuzzman, AKM; Haider, Mohammad Rafiqul; Allison, David B.

2016-01-01

Being able to rapidly detect a low air flow rate with high accuracy is essential for various applications in the automotive and biomedical industries. We have developed a thermal-based low air flow sensor with a low-power sensor readout for biomedical applications. The thermal-based air flow sensor comprises a heater and three pairs of temperature sensors that sense temperature differences due to laminar air flow. The thermal-based flow sensor was designed and simulated by using laminar flow, heat transfer in solids and fluids physics in COMSOL MultiPhysics software. The proposed sensor can detect air flow as low as 0.0064 m/sec. The readout circuit is based on a current- controlled ring oscillator in which the output frequency of the ring oscillator is proportional to the temperature differences of the sensors. The entire readout circuit was designed and simulated by using a 130-nm standard CMOS process. The sensor circuit features a small area and low-power consumption of about 22.6 µW with an 800 mV power supply. In the simulation, the output frequency of the ring oscillator and the change in thermistor resistance showed a high linearity with an R2 value of 0.9987. The low-power dissipation, high linearity and small dimensions of the proposed flow sensor and circuit make the system highly suitable for biomedical applications. PMID:28435186

Air classification: Potential treatment method for optimized recycling or utilization of fine-grained air pollution control residues obtained from dry off-gas cleaning high-temperature processing systems.

PubMed

Lanzerstorfer, Christof

2015-11-01

In the dust collected from the off-gas of high-temperature processes, usually components that are volatile at the process temperature are enriched. In the recycling of the dust, the concentration of these volatile components is frequently limited to avoid operation problems. Also, for external utilization the concentration of such volatile components, especially heavy metals, is often restricted. The concentration of the volatile components is usually higher in the fine fractions of the collected dust. Therefore, air classification is a potential treatment method to deplete the coarse material from these volatile components by splitting off a fines fraction with an increased concentration of those volatile components. In this work, the procedure of a sequential classification using a laboratory air classifier and the calculations required for the evaluation of air classification for a certain application were demonstrated by taking the example of a fly ash sample from a biomass combustion plant. In the investigated example, the Pb content in the coarse fraction could be reduced to 60% by separation of 20% fines. For the non-volatile Mg the content was almost constant. It can be concluded that air classification is an appropriate method for the treatment of off-gas cleaning residues. © The Author(s) 2015.

Combuston method of oil shale retorting

DOEpatents

Jones, Jr., John B.; Reeves, Adam A.

1977-08-16

A gravity flow, vertical bed of crushed oil shale having a two level injection of air and a three level injection of non-oxygenous gas and an internal combustion of at least residual carbon on the retorted shale. The injection of air and gas is carefully controlled in relation to the mass flow rate of the shale to control the temperature of pyrolysis zone, producing a maximum conversion of the organic content of the shale to a liquid shale oil. The parameters of the operation provides an economical and highly efficient shale oil production.

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.

A Controlled Environment System For Measuring Plant-Atmosphere Gas Exchange

Treesearch

James M. Brown

1975-01-01

Describes an inexpensive, efficient system for measuring plant-atmosphere gas exchange. Designed to measure transpiration from potted tree seedlings, it is readily adaptable for measuring other gas exchanges or gas exchange by plant parts. Light level, air and root temperature can be precisely controlled at minimum cost.

40 CFR 63.421 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Administrator and any other person. Controlled loading rack, for the purposes of § 63.420, means a loading rack... heat air pollutants to combustion temperatures. Uncontrolled loading rack means a loading rack used to load gasoline cargo tanks that is not a controlled loading rack. Vapor-tight gasoline cargo tank means...

EDUCATION, CHILDREN AND COMFORT.

ERIC Educational Resources Information Center

Iowa Univ., Iowa City.

TWO SIMILAR CLASSROOMS WERE SET UP IN THE LENNOX LIVING LABORATORY, DES MOINES, IOWA, ONE FOR EXPERIMENTAL GROUPS AND ONE FOR CONTROL GROUPS. TEMPERATURE, AIR CIRCULATION AND HUMIDITY CAN BE CONTROLLED AND MEASURED IN BOTH ROOMS. THE ROOMS ARE OF SIMILAR SIZE, LAYOUT AND CONSTRUCTION, THE THERMAL ENVIRONMENT BEING THE ONLY VARIABLE. THE FOLLOWING…

Automatic humidification system to support the assessment of food drying processes

NASA Astrophysics Data System (ADS)

Ortiz Hernández, B. D.; Carreño Olejua, A. R.; Castellanos Olarte, J. M.

2016-07-01

This work shows the main features of an automatic humidification system to provide drying air that match environmental conditions of different climate zones. This conditioned air is then used to assess the drying process of different agro-industrial products at the Automation and Control for Agro-industrial Processes Laboratory of the Pontifical Bolivarian University of Bucaramanga, Colombia. The automatic system allows creating and improving control strategies to supply drying air under specified conditions of temperature and humidity. The development of automatic routines to control and acquire real time data was made possible by the use of robust control systems and suitable instrumentation. The signals are read and directed to a controller memory where they are scaled and transferred to a memory unit. Using the IP address is possible to access data to perform supervision tasks. One important characteristic of this automatic system is the Dynamic Data Exchange Server (DDE) to allow direct communication between the control unit and the computer used to build experimental curves.

Thermally Robust Polymer Dielectric Systems for Air Force Wide-Temperature Power Electronics Applications

DTIC Science & Technology

2009-07-01

power supply, a temperature controller and a vacuum controller. A vacuum of < 1 )1 torr is achieved with a combination of a turbo pump and a... scroll pump system. The sanlple probing is accomplished with a 3-axis molybdenum probing rod test fixture .. The dielectric measurements on the...water. The films were dried at ~ 0.1 torr vacuum and 80-85°C in an oven for several days. Circular films varying in diameter from 2" to 4" were

Using Field-Metered Data to Quantify Annual Energy Use of Portable Air Conditioners

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

Burke, Thomas; Willem, Henry; Ni, Chun Chun

2014-12-01

As many regions of the United States experience rising temperatures, consumers have come to rely increasingly on cooling appliances (including portable air conditioners) to provide a comfortable indoor temperature. Home occupants sometimes use a portable air conditioner (PAC) to maintain a desired indoor temperature in a single room or enclosed space. Although PACs in residential use are few compared to centrally installed and room air conditioning (AC) units, the past few years have witnessed an increase of PACs use throughout the United States. There is, however, little information and few research projects focused on the energy consumption and performance ofmore » PACs, particularly studies that collect information from field applications of PACs. The operation and energy consumption of PACs may differ among geographic locations and households, because of variations in cooling load, frequency, duration of use, and other user-selected settings. In addition, the performance of building envelope (thermal mass and air leakage) as well as inter-zonal mixing within the building would substantially influence the ability to control and maintain desirable indoor thermal conditions. Lawrence Berkeley National Laboratory (LBNL) conducted an initial field-metering study aimed at increasing the knowledge and data related to PAC operation and energy consumption in the United States.« less

Factors affecting decay of Salmonella Birkenhead and coliphage MS2 during mesophilic anaerobic digestion and air drying of sewage sludge.

PubMed

Mondal, Tania; Rouch, Duncan A; Thurbon, Nerida; Smith, Stephen R; Deighton, Margaret A

2015-06-01

Factors affecting the decay of Salmonella Birkenhead and coliphage, as representatives of bacterial and viral pathogens, respectively, during mesophilic anaerobic digestion (MAD) and air drying treatment of anaerobically digested sewage sludge were investigated. Controlled concentrations of S. Birkenhead were inoculated into non-sterile, autoclaved, γ-irradiated and nutrient-supplemented sludge and cultures were incubated at 37 °C (MAD sludge treatment temperature) or 20 °C (summer air drying sludge treatment temperature). Nutrient limitation caused by microbial competition was the principal mechanism responsible for the decay of S. Birkenhead by MAD and during air drying of digested sludge. The effects of protease activity in sludge on MS2 coliphage decay in digested and air dried sludge were also investigated. MS2 coliphage showed a 3.0-3.5 log10 reduction during incubation with sludge-protease extracts at 37 °C for 25 h. Proteases produced by indigenous microbes in sludge potentially increase coliphage inactivation and may therefore have a significant role in the decay of enteric viruses in sewage sludge. The results help to explain the loss of viability of enteric bacteria and viral pathogens with treatment process time and contribute to fundamental understanding of the various biotic inactivation mechanisms operating in sludge treatment processes at mesophilic and ambient temperatures.

Control of Toxic Chemicals in Puget Sound, Phase 3: Study Of Atmospheric Deposition of Air Toxics to the Surface of Puget Sound

DTIC Science & Technology

2007-01-01

deposition directly to Puget Sound was an important source of PAHs, polybrominated diphenyl ethers (PBDEs), and heavy metals . In most cases, atmospheric...versus Atmospheric Fluxes ........................................................................66  PAH Source Apportionment ...temperature inversions) on air quality during the wet season. A semi-quantitative apportionment study permitted a first-order characterization of source

Influence of spatial temperature estimation method in ecohydrologic modeling in the western Oregon Cascades

Treesearch

E. Garcia; C.L. Tague; J. Choate

2013-01-01

Most spatially explicit hydrologic models require estimates of air temperature patterns. For these models, empirical relationships between elevation and air temperature are frequently used to upscale point measurements or downscale regional and global climate model estimates of air temperature. Mountainous environments are particularly sensitive to air temperature...

A Comparison between Temperature-Controlled Laminar Airflow Device and a Room Air-Cleaner in Reducing Exposure to Particles While Asleep

PubMed Central

Spilak, Michal P.; Sigsgaard, Torben; Takai, Hisamitsu; Zhang, Guoqiang

2016-01-01

People spend approximately one third of their life sleeping. Exposure to pollutants in the sleep environment often leads to a variety of adverse health effects, such as development and exacerbation of asthma. Avoiding exposure to these pollutants by providing a sufficient air quality in the sleep environment might be a feasible method to alleviate these health symptoms. We performed full-scale laboratory measurements using a thermal manikin positioned on an experimental bed. Three ventilation settings were tested: with no filtration system operated, use of portable air cleaner and use of a temperature-controlled laminar airflow (TLA) device. The first part of the experiment investigated the air-flow characteristics in the breathing zone. In the second part, particle removal efficiency was estimated. Measured in the breathing zone, the room air cleaner demonstrated high turbulence intensity, high velocity and turbulence diffusivity level, with a particle reduction rate of 52% compared to baseline after 30 minutes. The TLA device delivered a laminar airflow to the breathing zone with a reduction rate of 99.5%. During a periodical duvet lifting mimicking a subject’s movement in bed, the particle concentration was significantly lower with the TLA device compared to the room air cleaner. The TLA device provided a barrier which significantly reduced the introduction of airborne particles into the breathing zone. Further studies should be conducted for the understanding of the transport of resuspended particles between the duvet and the laying body. PMID:27898693

A Comparison between Temperature-Controlled Laminar Airflow Device and a Room Air-Cleaner in Reducing Exposure to Particles While Asleep.

PubMed

Spilak, Michal P; Sigsgaard, Torben; Takai, Hisamitsu; Zhang, Guoqiang

2016-01-01

People spend approximately one third of their life sleeping. Exposure to pollutants in the sleep environment often leads to a variety of adverse health effects, such as development and exacerbation of asthma. Avoiding exposure to these pollutants by providing a sufficient air quality in the sleep environment might be a feasible method to alleviate these health symptoms. We performed full-scale laboratory measurements using a thermal manikin positioned on an experimental bed. Three ventilation settings were tested: with no filtration system operated, use of portable air cleaner and use of a temperature-controlled laminar airflow (TLA) device. The first part of the experiment investigated the air-flow characteristics in the breathing zone. In the second part, particle removal efficiency was estimated. Measured in the breathing zone, the room air cleaner demonstrated high turbulence intensity, high velocity and turbulence diffusivity level, with a particle reduction rate of 52% compared to baseline after 30 minutes. The TLA device delivered a laminar airflow to the breathing zone with a reduction rate of 99.5%. During a periodical duvet lifting mimicking a subject's movement in bed, the particle concentration was significantly lower with the TLA device compared to the room air cleaner. The TLA device provided a barrier which significantly reduced the introduction of airborne particles into the breathing zone. Further studies should be conducted for the understanding of the transport of resuspended particles between the duvet and the laying body.

NBC Contamination Survivability, Large Item Exteriors

DTIC Science & Technology

1998-04-17

environment. Ability to control temperature , relative humidity (RH), and wind speed is required. The facility must be designed to ensure safe and...2.2 Instrumentation. Measuring Devices Permissible Error of Measurement Air temperature ±0.5°C Relative humidity (RH) ±5 % Wind speed ±0.1 rm/sec Still...process, excluding monitoring, should last no longer than 75 minutes. (3) The item surface temperature is 30’C and exterior wind speed is no greater

Improved heat recovery and high-temperature clean-up for coal-gas fired combustion turbines

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

Barthelemy, N.M.; Lynn, S.

1991-07-01

This study investigates the performance of an Improved Heat Recovery Method (IHRM) applied to a coal-gas fired power-generating system using a high-temperature clean-up. This heat recovery process has been described by Higdon and Lynn (1990). The IHRM is an integrated heat-recovery network that significantly increases the thermal efficiency of a gas turbine in the generation of electric power. Its main feature is to recover both low- and high-temperature heat reclaimed from various gas streams by means of evaporating heated water into combustion air in an air saturation unit. This unit is a packed column where compressed air flows countercurrently tomore » the heated water prior to being sent to the combustor, where it is mixed with coal-gas and burned. The high water content of the air stream thus obtained reduces the amount of excess air required to control the firing temperature of the combustor, which in turn lowers the total work of compression and results in a high thermal efficiency. Three designs of the IHRM were developed to accommodate three different gasifying process. The performances of those designs were evaluated and compared using computer simulations. The efficiencies obtained with the IHRM are substantially higher those yielded by other heat-recovery technologies using the same gasifying processes. The study also revealed that the IHRM compares advantageously to most advanced power-generation technologies currently available or tested commercially. 13 refs., 34 figs., 10 tabs.« less

Comparison of Surface Mountain Climate With Equivalent Free Air Parameters Extracted From NCEP/NCAR Reanalysis: Kilimanjaro, Tanzania.

NASA Astrophysics Data System (ADS)

Pepin, N. C.; Hardy, D.; Duane, W.; Losleben, M.

2007-12-01

It is difficult to predict future climate changes in areas of complex relief, since mountains generate their own climates distinct from the free atmosphere. Thus trends in climate at the mountain surface are different from those in the free air. We compare surface climate (temperature and vapour pressure) measured at seven elevations on the south-western slope of Kilimanjaro, the tallest free standing mountain in Africa, with equivalent observations in the free atmosphere from NCEP/NCAR reanalysis data for September 2004 to January 2006. Correlations between daily surface and free air temperature anomalies are greatest at low elevations below 2500 metres, meaning that synoptic (inter-diurnal) variability is the major control here. However, temperatures and moisture on the higher slopes above the treeline (3000 m) are decoupled from the free atmosphere, showing intense heating/cooling by day/night and import of moisture from lower elevations during the day. The lower forested slopes thus act as a moisture source, with large vapour pressure excesses reported in comparison with the free atmosphere (>5 hPa) which move upslope during daylight and subside downslope at night. Strong seasonal contrasts are shown in the vigour of the montane thermal circulation, but interactions with free air circulation (as represented by flow indices developed from reanalysis wind components) are complex. Upper air flow strength and direction (at 500 mb) have limited influence on surface heating and upslope moisture advection, which are dominated by the diurnal cycle rather than inter-diurnal synoptic controls. Thus local changes in surface characteristics (e.g. deforestation) could have a direct influence on the mountain climate of Kilimanjaro, making the upper slopes somewhat divorced from larger scale advective changes associated with global warming.

What's All the Talc About? Air Entrainment in Dilute Pyroclastic Density Currents

NASA Astrophysics Data System (ADS)

Marshall, B. J.; Andrews, B. J.; Fauria, K.

2015-12-01

A quantitative understanding of air entrainment is critical to predicting the behaviors of dilute Pyroclastic Density Currents (PDCs), including runout distance, liftoff, and mass fractionation into co-PDC plumes. We performed experiments in an 8.5x6x2.6 meter tank using 20 micron talc powder over a range of conditions to describe air entrainment as a function of temperature, duration and mass flux. The experiments are reproducible and are scaled with respect to the densimetric and thermal Richardson numbers (Ri and RiT), Froude number, thermal to kinetic energy density ratio (TEb/KE), Stokes number, and Settling number, such that they are dynamically similar to natural dilute PDCs. Experiments are illuminated with a swept laser sheet and imaged at 1000 Hz to create 3D reconstructions of the currents, with ~1-2 cm resolution, at up to 1.5 Hz. An array of 30 high-frequency thermocouples record the precise temperature in the currents at 3 Hz. Bulk entrainment rates are calculated based on measured current volumes, surface areas, temperatures and velocities. Entrainment rates vary from ~0-0.9 and do not show simple variation with TEb/KE, Ri, or RiT. Entrainment does, however, increase with decreasing eruption duration and increasing mass flux. Our results suggest that current heads entrain air more efficiently than current bodies (>0.5 compared to ~0.1). Because shorter duration currents have proportionally larger heads, their bulk entrainment rates are controlled by those heads, whereas longer duration currents are dominated by their bodies. Our experiments demonstrate that air entrainment, which exerts a fundamental control on PDC runout and liftoff, varies spatially and temporally within PDCs.

Experimental investigation of drying characteristics of cornelian cherry fruits ( Cornus mas L.)

NASA Astrophysics Data System (ADS)

Ozgen, Filiz

2015-03-01

Major target of present paper is to investigate the drying kinetics of cornelian cherry fruits ( Cornus mas L.) in a convective dryer, by varying the temperature and the velocity of drying air. Freshly harvested fruits are dried at drying air temperature of 35, 45 and 55 °C. The considered drying air velocities are V air = 1 and 1.5 m/s for each temperature. The required drying time is determined by taking into consideration the moisture ratio measurements. When the moisture ratio reaches up to 10 % at the selected drying air temperature, then the time is determined ( t = 40-67 h). The moisture ratio, fruit temperature and energy requirement are presented as the functions of drying time. The lowest drying time (40 h) is obtained when the air temperature is 55 °C and air velocity is 1.5 m/s. The highest drying time (67 h) is found under the conditions of 35 °C temperature and 1 m/s velocity. Both the drying air temperature and the air velocity significantly affect the required energy for drying system. The minimum amount of required energy is found as 51.12 kWh, at 55 °C and 1 m/s, whilst the maximum energy requirement is 106.7 kWh, at 35 °C and 1.5 m/s. It is also found that, air temperature significantly influences the total drying time. Moreover, the energy consumption is decreasing with increasing air temperature. The effects of three parameters (air temperature, air velocity and drying time) on drying characteristics have also been analysed by means of analysis of variance method to show the effecting levels. The experimental results have a good agreement with the predicted ones.

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.

Greenland Ice Sheet Melt from MODIS and Associated Atmospheric Variability

NASA Technical Reports Server (NTRS)

Hakkinen, Sirpa; Hall, Dorothy K.; Shuman, Christopher A.; Worthen, Denise L.; DiGirolamo, Nicolo E.

2014-01-01

Daily June-July melt fraction variations over the Greenland Ice Sheet (GIS) derived from the MODerate-resolution Imaging Spectroradiometer (MODIS) (2000-2013) are associated with atmospheric blocking forming an omega-shape ridge over the GIS at 500hPa height (from NCEPNCAR). Blocking activity with a range of time scales, from synoptic waves breaking poleward ( 5 days) to full-fledged blocks (5 days), brings warm subtropical air masses over the GIS controlling daily surface temperatures and melt. The temperature anomaly of these subtropical air mass intrusions is also important for melting. Based on the largest MODIS melt years (2002 and 2012), the area-average temperature anomaly of 2 standard deviations above the 14-year June-July mean, results in a melt fraction of 40 or more. Summer 2007 had the most blocking days, however atmospheric temperature anomalies were too small to instigate extreme melting.

Thermo-responsive gels that absorb moisture and ooze water.

PubMed

Matsumoto, Kazuya; Sakikawa, Nobuki; Miyata, Takashi

2018-06-13

The water content of thermo-responsive hydrogels can be drastically altered by small changes in temperature because their polymer chains change from hydrophilic to hydrophobic above their low critical solution temperature (LCST). In general, such smart hydrogels have been utilized in aqueous solutions or in their wet state, and no attempt has been made to determine the phase-transition behavior of the gels in their dried states. Here we demonstrate an application of the thermo-responsive behavior of an interpenetrating polymer network (IPN) gel comprising thermo-responsive poly(N-isopropylacrylamide) and hydrophilic sodium alginate networks in their dried states. The dried IPN gel absorbs considerable moisture from air at temperatures below its LCST and oozes the absorbed moisture as liquid water above its LCST. These phenomena provide energy exchange systems in which moisture from air can be condensed to liquid water using the controllable hydrophilic/hydrophobic properties of thermo-responsive gels with a small temperature change.

AIRQino, a low-cost air quality mobile platform

NASA Astrophysics Data System (ADS)

Zaldei, Alessandro; Vagnoli, Carolina; Di Lonardo, Sara; Gioli, Beniamino; Gualtieri, Giovanni; Toscano, Piero; Martelli, Francesca; Matese, Alessandro

2015-04-01

Recent air quality regulations (Directive 2008/50/EC) enforce the transition from point-based monitoring networks to new tools that must be capable of mapping and forecasting air quality on the totality of land area, and therefore the totality of citizens. This implies new technologies such as models and additional indicative measurements, are needed in addition to accurate fixed air quality monitoring stations, that until now have been taken as reference by local administrators for the enforcement of various mitigation strategies. However, due to their sporadic spatial distribution, they cannot describe the highly resolved spatial pollutant variations within cities. Integrating additional indicative measurements may provide adequate information on the spatial distribution of the ambient air quality, also allowing for a reduction of the required minimum number of fixed sampling points, whose high cost and complex maintenance still remain a crucial concern for local administrators. New low-cost and small size sensors are becoming available, that could be employed in air quality monitoring including mobile applications. However, accurate assessment of their accuracy and performance both in controlled and real monitoring conditions is crucially needed. Quantifying sensor response is a significant challenge due to the sensitivity to ambient temperature and humidity and the cross-sensitivity to others pollutant species. This study reports the development of an Arduino compatible electronic board (AIRQino) which integrates a series of low-cost metal oxide and NDIR sensors for air quality monitoring, with sensors to measure air temperature, relative humidity, noise, solar radiation and vertical acceleration. A comparative assessment was made for CO2, CO, NO2, CH4, O3, VOCs concentrations, temperature and relative humidity. A controlled climatic chamber study (-80°C / +80°C) was performed to verify temperature and humidity interference using reference gas cylinders and high quality reference sensors. The AIRQino was installed on mobile vectors such as bikes, buses and trams in the cities of Firenze and Siracusa (Italy), that send data real-time to a Web portal. By integrating a microprocessor unit it is capable of directly updating calibration coefficients to provide corrected sensor output as digital string through RS232 serial port. Results from the lab tests and the 'real world' mobile applications are presented and discussed, to assess to what extent this sensor technology might be useful for the development of portable, compact, wireless and cost-effective system for air quality monitoring in urban areas at high spatio-temporal resolution.

Empirical downscaling of daily minimum air temperature at very fine resolutions in complex terrain

Treesearch

Zachary A. Holden; John T. Abatzoglou; Charles H. Luce; L. Scott Baggett

2011-01-01

Available air temperature models do not adequately account for the influence of terrain on nocturnal air temperatures. An empirical model for night time air temperatures was developed using a network of one hundred and forty inexpensive temperature sensors deployed across the Bitterroot National Forest, Montana. A principle component analysis (PCA) on minimum...

UV Raman spectroscopy of H2-air flames excited with a narrowband KrF laser

NASA Technical Reports Server (NTRS)

Shirley, John A.

1990-01-01

Raman spectra of H2 and H2O in flames excited by a narrowband KrF excimer laser are reported. Observations are made over a porous-plug, flat-flame burner reacting H2 in air, fuel-rich with nitrogen dilution to control the temperature, and with an H2 diffusion flame. Measurements made from UV Raman spectra show good agreement with measurements made by other means, both for gas temperature and relative major species concentrations. Laser-induced fluorescence interferences arising from OH and O2 are observed in emission near the Raman spectra. These interferences do not preclude Raman measurements, however.

Empowering smartphone users with sensor node for air quality measurement

NASA Astrophysics Data System (ADS)

Oletic, Dinko; Bilas, Vedran

2013-06-01

We present an architecture of a sensor node developed for use with smartphones for participatory sensing of air quality in urban environments. Our solution features inexpensive metal-oxide semiconductor gas sensors (MOX) for measurement of CO, O3, NO2 and VOC, along with sensors for ambient temperature and humidity. We focus on our design of sensor interface consisting of power-regulated heater temperature control, and the design of resistance sensing circuit. Accuracy of the sensor interface is characterized. Power consumption of the sensor node is analysed. Preliminary data obtained from the CO gas sensors in laboratory conditions and during the outdoor field-test is shown.

[Effects of forest gap size and uprooted microsite on the microclimate in Pinus koraiensis-dominated broad-leaved mixed forest].

PubMed

Duan, Wen-biao; Du, Shan; Chen, Li-xin; Wang, Li-xia; Wei, Quan-shuai; Zhao, Jian-hui

2013-08-01

Three representative forest gaps with pit-mound microsites formed by uprooted trees were selected within the 2.55 hm2 plot in a Pinus koraiensis-dominated broad-leaved mixed forest in Xiao Xing'an Mountains of Northeast China. The cleared land and closed stand were set up as the controls, and the PAR, air temperature and relative humidity in the centers of different size gaps and in mound top as well as the total radiation and precipitation in the gap centers were measured between July and September, 2011 by using multichannel automatic meteorological stations. The differences of the microclimate between the gap centers and mound top in different months were compared, and the monthly and diurnal variations of the microclimatic factors in the gap centers and in the mound top under typical weather conditions were analyzed. The results showed that the mean monthly PAR and air temperature in the three gaps of different sizes were in the order of large gap > medium gap > small gap, and the mean monthly relative humidity was in the order of small gap > medium gap > large gap. For the same size gap, the mean monthly PAR and air temperature were higher in the mound top than in the gap center, whereas the mean monthly relative humidity was higher in the gap center than in the mound top. Both the mean monthly total radiation and the mean monthly air temperature in the forest gaps and in the controls were in the order of July > August > September and of cleared land > large gap > medium gap > small gap > closed stand, while the mean monthly relative humidity was in the order of closed stand > small gap > medium gap > large gap > cleared land. The differences in the mean monthly relative humidity between closed stand and various gaps and between closed stand and cleared land reached significant level. The monthly precipitation from July to September decreased in the order of cleared land > large gap > medium gap > small gap > closed stand. Whether in sunny days or in overcast days, the mean daily PAR and air temperature were higher in mound top than in gap center, and the mean daily relative humidity was in opposite. Whether in mound top or in gap center, the mean daily PAR and air temperature were higher in sunny days than in overcast days, while the mean daily relative humidity was higher in overcast days than in sunny days.

High-Efficiency Co/CoxSy@S,N-Codoped Porous Carbon Electrocatalysts Fabricated from Controllably Grown Sulfur- and Nitrogen-Including Cobalt-Based MOFs for Rechargeable Zinc-Air Batteries.

PubMed

Liu, Shengwen; Zhang, Xian; Wang, Guozhong; Zhang, Yunxia; Zhang, Haimin

2017-10-04

Developing bifunctional oxygen electrocatalysts with superior catalytic activities of oxygen reduction reaction (ORR) and oxygen revolution reaction (OER) is crucial to their practical energy storage and conversion applications. In this work, we report the fabrication of Co/Co x S y @S,N-codoped porous carbon structures with various morphologies, specific surface areas, and pore structures, derived from controllably grown Co-based metal-organic frameworks with S- and N-containing organic ligands (thiophene-2,5-dicarboxylate, Tdc; and 4,4'-bipyridine, bpy) utilizing solvent effect (e.g., water and methanol) under room temperature and hydrothermal conditions. The results demonstrate that Co/Co x S y @S,N-codoped carbon fibers fabricated at a pyrolytic temperature of 800 °C (Co/Co x S y @SNCF-800) from Co-MOFs fibers fabricated in methanol under hydrothermal conditions as electrocatalysts exhibit superior bifunctional ORR and OER activities in alkaline media, endowing them as air cathodic catalysts in rechargeable zinc-air batteries with high power density and good durability.

Prolonging thermal barrier coated specimen life by thermal cycle management

NASA Technical Reports Server (NTRS)

Hendricks, R. C.; Mcdonald, G.; Poolos, N. P.

1981-01-01

Thermal barrier coatings applied to the heated side of engine components such as seals, combustor, and blades of a gas turbine offer a potential increase in efficiency through the use of higher gas temperatures or less cooling air or benefits arising from extended component life by reducing component metal temperatures. The considered investigation has the objective to show that while a thermal barrier coated (TBC) specimen can be brought to a fixed temperature using various fuel-air ratio (F/A) values, lower calculated stresses are associated with lower (F/A) values. This implies that control of (F/A) values (i.e., rates of heat input) during the starting transient and to a lesser extent during shutdown and operation, offers a potential method of improving TBC lifetime through thermal cycle management.

The influence of flow modification on air and PCM temperatures in an accumulative heat exchanger

NASA Astrophysics Data System (ADS)

Borcuch, Marcin; Musiał, Michał; Sztekler, Karol; Kalawa, Wojciech; Gumuła, Stanisław; Stefański, Sebastian

2018-06-01

The paper presents the influence of flow modification on the operation of an accumulative heat exchanger. This device can be used as a regenerator in ventilation and air supply systems. A heat exchanger uses ceresine (a mixture of paraffins) as a phase change material (PCM). The aim of this research was to determine the effect of flow modification on temperature distribution and pressure drops in the device. The introduction contains a short description of the test stand used, including the accumulative heat exchanger, the guide vanes, and the locations of measurement and control equipment. We found that additional objects limited vortex structures, increased the inside temperature, and dropped the pressure along the heat exchanger. Guidelines for further research are proposed and briefly discussed.

Effect of Air Temperature and Relative Humidity at Various Fuel-Air Ratios on Exhaust Emissions on a Per-Mode Basis of an AVCO Lycoming 0-320 Diad Light Aircraft Engine: Volume 1: Results and Plotted Data

NASA Technical Reports Server (NTRS)

Skorobatckyi, M.; Cosgrove, D. V.; Meng, P. R.; Kempe, E. E., Jr.

1978-01-01

A carbureted four cylinder air cooled 0-320 DIAD Lycoming aircraft engine was tested to establish the effects of air temperature and humidity at various fuel-air ratios on the exhaust emissions on a per-mode basis. The test conditions include carburetor lean out at air temperatures of 50, 59, 80, and 100 F at relative humidities of 0, 30, 60, and 80 percent. Temperature humidity effects at the higher values of air temperature and relative humidity tested indicated that the HC and CO emissions increased significantly, while the NOx emissions decreased. Even at a fixed fuel air ratio, the HC emissions increase and the NOx emissions decrease at the higher values of air temperature and humidity.

Effect of air temperature and relative humidity at various fuel-air ratios on exhaust emissions on a per-mode basis of an Avco Lycoming 0-320 DIAD light aircraft engine. Volume 2: Individual data points

NASA Technical Reports Server (NTRS)

Skorobatckyi, M.; Cosgrove, D. V.; Meng, P. R.; Kempke, E. R.

1976-01-01

A carbureted four cylinder air cooled 0-320 DIAD Lycoming aircraft engine was tested to establish the effects of air temperature and humidity at various fuel-air ratios on the exhaust emissions on a per-mode basis. The test conditions included carburetor lean-out at air temperatures of 50, 59, 80, and 100 F at relative humidities of 0, 30, 60, and 80 percent. Temperature-humidity effects at the higher values of air temperature and relative humidity tested indicated that the HC and CO emissions increased significantly, while the NOx emissions decreased. Even at a fixed fuel-air ratio, the HC emissions increase and the NOx emissions decrease at the higher values of air temperature and humidity. Volume II contains the data taken at each of the individual test points.