Mode-Stirred Method Implementation for HIRF Susceptibility Testing and Results Comparison with Anechoic Method

NASA Technical Reports Server (NTRS)

Nguyen, Truong X.; Ely, Jay J.; Koppen, Sandra V.

2001-01-01

This paper describes the implementation of mode-stirred method for susceptibility testing according to the current DO-160D standard. Test results on an Engine Data Processor using the implemented procedure and the comparisons with the standard anechoic test results are presented. The comparison experimentally shows that the susceptibility thresholds found in mode-stirred method are consistently higher than anechoic. This is consistent with the recent statistical analysis finding by NIST that the current calibration procedure overstates field strength by a fixed amount. Once the test results are adjusted for this value, the comparisons with the anechoic results are excellent. The results also show that test method has excellent chamber to chamber repeatability. Several areas for improvements to the current procedure are also identified and implemented.

Test program to provide confidence in liquid oxygen cooling of hydrocarbon fueled rocket thrust chambers

NASA Technical Reports Server (NTRS)

Armstrong, E. S.

1986-01-01

An experimental program has been planned at the NASA Lewis Research Center to build confidence in the feasibility of liquid oxygen cooling for hydrocarbon fueled rocket engines. Although liquid oxygen cooling has previously been incorporated in test hardware, more runtime is necessary to gain confidence in this concept. In the previous tests, small oxygen leaks developed at the throat of the thrust chamber and film cooled the hot-gas side of the chamber wall without resulting in catastrophic failure. However, more testing is necessary to demonstrate that a catastrophic failure would not occur if cracks developed further upstream between the injector and the throat, where the boundary layer has not been established. Since under normal conditions cracks are expected to form in the throat region of the thrust chamber, cracks must be initiated artificially in order to control their location. Several methods of crack initiation are discussed in this report. Four thrust chambers, three with cracks and one without, should be tested. The axial location of the cracks should be varied parametrically. Each chamber should be instrumented to determine the effects of the cracks, as well as the overall performance and durability of the chambers.

Hydrocarbon-fuel/combustion-chamber-liner materials compatibility

NASA Technical Reports Server (NTRS)

Gage, Mark L.

1990-01-01

Results of material compatibility experiments using hydrocarbon fuels in contact with copper-based combustion chamber liner materials are presented. Mil-Spec RP-1, n- dodecane, propane, and methane fuels were tested in contact with OFHC, NASA-Z, and ZrCu coppers. Two distinct test methods were employed. Static tests, in which copper coupons were exposed to fuel for long durations at constant temperature and pressure, provided compatibility data in a precisely controlled environment. Dynamic tests, using the Aerojet Carbothermal Test Facility, provided fuel and copper compatibility data under realistic booster engine service conditions. Tests were conducted using very pure grades of each fuel and fuels to which a contaminant, e.g., ethylene or methyl mercaptan, was added to define the role played by fuel impurities. Conclusions are reached as to degradation mechanisms and effects, methods for the elimination of these mechanisms, selection of copper alloy combustion chamber liners, and hydrocarbon fuel purchase specifications.

Simulations in the Analysis of Experimental Data Measured by BM@N Drift Chambers

NASA Astrophysics Data System (ADS)

Fedorišin, Ján

2018-02-01

The drift chambers (DCH's) are an important part of the tracking system of the BM@N experiment designed to study the production of baryonic matter at the Nuclotron energies. The method of particle hit and track reconstruction in the drift chambers has been already proposed and tested on the BM@N deuteron beam data. In this study the DCH's are first locally and globally aligned, and subsequently the consistency of the track reconstruction chain is tested by two methods. The first one is based on the backward extrapolation of the DCH reconstructed deuteron beam to a position where its deflection in the BM@N magnetic field begins. The second method reconstructs the deuteron beam momentum through its deflection angle. Both methods confirm correctness of the track reconstruction algorithm.

Methods of Evaluating Protective Clothing Relative to Heat and Cold Stress: Thermal Manikin, Biomedical Modeling, and Human Testing

DTIC Science & Technology

2011-01-01

in the climatic chamber housing the manikin. The most widely accepted test procedures for the operation of a TM are published by ASTM International...insulation value of a complete clothing ensemble. It requires a TM surface temperature of 35◦C and a climatic chamber controlled at 23◦C, 50% relative... climatic chamber controlled at 35◦C, 40% relative humidity, with a 0.4 m/sec air velocity. In addition to the tests conducted at 0.4 m/sec, USARIEM

Application test of a Detection Method for the Enclosed Turbine Runner Chamber

NASA Astrophysics Data System (ADS)

Liu, Yunlong; Shen, Dingjie; Xie, Yi; Yang, Xiangwei; Long, Yi; Li, Wenbo

2017-06-01

At present, for the existing problems of the testing methods for the key hidden metal components of the turbine runner chamber, such as the poor reliability, the inaccurate locating and the larger detection blind spots of the detection device, under the downtime without opening the cover of the hydropower turbine runner chamber, an automatic detection method based on real-time image acquisition and simulation comparison techniques was proposed. By using the permanent magnet wheel, the magnetic crawler which carry the real-time image acquisition device, could complete the crawling work on the inner surface of the enclosed chamber. Then the image acquisition device completed the real-time collection of the scene image of the enclosed chamber. According to the obtained location by using the positioning auxiliary device, the position of the real-time detection image in a virtual 3D model was calibrated. Through comparing of the real-time detection images and the computer simulation images, the defects or foreign matter fall into could be accurately positioning, so as to repair and clean up conveniently.

Monitoring electrolyte concentrations in redox flow battery systems

DOEpatents

Chang, On Kok; Sopchak, David Andrew; Pham, Ai Quoc; Kinoshita, Kimio

2015-03-17

Methods, systems and structures for monitoring, managing electrolyte concentrations in redox flow batteries are provided by introducing a first quantity of a liquid electrolyte into a first chamber of a test cell and introducing a second quantity of the liquid electrolyte into a second chamber of the test cell. The method further provides for measuring a voltage of the test cell, measuring an elapsed time from the test cell reaching a first voltage until the test cell reaches a second voltage; and determining a degree of imbalance of the liquid electrolyte based on the elapsed time.

Method of determining operation parameters of stand tests of vehicle suspension elements under conditions of ultra-low temperatures

NASA Astrophysics Data System (ADS)

Fedyanov, E. A.; Sokolov-Dobrev, N. S.; Ljashenko, M. V.; Shekhovtsov, V. V.; Potapov, P. V.; Dolotov, A. A.; Klementiev, E. V.

2018-05-01

This article presents the description of the method for estimation of heat flows characteristic during research of operability of suspension elements under the conditions of ultralow temperature. The mentioned research is performed at the test bench created in VSTU. Solid carbon dioxide (also known as artificial ice) is used as the coolant. The method provides evaluation of required quantity of artificial ice and cooling dynamics of the test unit in the insulated low-temperature chamber with structurally specified parameters of heat insulation. Also the method allows computation of heat intake into the chamber volume.

Fire toxicology program. JSC methodology

NASA Technical Reports Server (NTRS)

Schneider, H.; Bafus, D.

1978-01-01

Toxicological testing of spacecraft materials was initiated in 1965. Toxicological evaluations of the pyrolysis/combustion products of candidate spacecraft materials were performed using a modified 142 liter Bethlehem Chamber equipped with a Linberg Model 55031 furnace external to the chamber. In all of the assessments, lethality was chosen as the endpoint. A new pyrolysis/combustion chamber was developed for toxicological testing and ranking of both spacecraft and aircraft materials. The pyrolysis/combustion chamber permits the use of both behavior and physiological measurements as indicators of incapacitation. Methods were developed which employ high resolution gas chromatography/mass spectrometry to generate chamber atmospheric profiles which indicate the reproductibility of pyrolysate concentrations. The atmospheric volatile profiles in combination with CO, CO2, and O2 analysis indicates that small chamber equipped with an internal furnace will give reproducible results.

A Preliminary Design of a Calibration Chamber for Evaluating the Stability of Unsaturated Soil Slope

NASA Astrophysics Data System (ADS)

Hsu, H.-H.

2012-04-01

The unsaturated soil slopes, which have ground water tables and are easily failure caused by heavy rainfalls, are widely distributed in the arid and semi-arid areas. For analyzing the stability of slope, in situ tests are the direct methods to obtain the test site characteristics. The cone penetration test (CPT) is a popular in situ test method. Some of the CPT empirical equations established from calibration chamber tests. The CPT performed in calibration chamber was commonly used clean quartz sand as testing material in the past. The silty sand is observed in many actual slopes. Because silty sand is relatively compressible than quartz sand, it is not suitable to apply the correlations between soil properties and CPT results built from quartz sand to silty sand. The experience on CPT calibration in silty sand has been limited. CPT calibration tests were mostly performed in dry or saturated soils. The condition around cone tip during penetration is assumed to be fully drained or fully undrained, yet it was observed to be partially drained for unsaturated soils. Because of the suction matrix has a great effect on the characteristics of unsaturated soils, they are much sensitive to the water content than saturated soils. The design of an unsaturated calibration chamber is in progress. The air pressure is supplied from the top plate and the pore water pressure is provided through the high air entry value ceramic disks located at the bottom plate of chamber cell. To boost and uniform distribute the unsaturated effect, four perforated burettes are installed onto the ceramic disks and stretch upwards to the midheight of specimen. This paper describes design concepts, illustrates this unsaturated calibration chamber, and presents the preliminary test results.

[Comparison of anterior chamber angle examination by UBM, SL-OCT and gonioscopy].

PubMed

Liu, Rui-jue; Wang, Men; Xia, Wen-tao; Yu, Xiao-ying; Chen, Jie-min; Zhou, Shu; Peng, Shu-ya; Liu, Dong-mei

2014-08-01

To compare the agreement of anterior chamber angle examination by ultrasound biomicroscope (UBM), slit lamp optical coherence tomography (SL-OCT), and gonioscopy in angle recession and angle closure. The anterior chamber angle was measured with UBM, SL-OCT and gonioscopy in turns for temporal, nasal, superior and inferior quadrant in the same dark room. The results were compared with the agreement of the three methods in angle recession and angle closure by χ2 test and Kappa test. There were no statistically significant differences of the three methods in testing angle closure and angle recession (P>0.05). The consistency of UBM and gonioscopy was better (Kappa value of 0.882) than that of SL-OCT and gonioscopy (Kappa value of 0.624). When testing angle recession, UBM is better than SL-OCT with gonioscopy as the standard. When testing angle closure, UBM, SL-OCT and gonioscopy have good agreement.

Direct measurement of air kerma rate in air from CDCS J-type caesium-137 therapy sources using a Farmer ionization chamber.

PubMed

Poynter, A J

2000-04-01

A simple method for directly measuring the reference air kerma rate from J-type 137Cs sources using a Farmer 2571 chamber has been evaluated. The method is useful as an independent means of verifying manufacturers' test data.

Nondestructive tests of regenerative chambers. [evaluating nondestructive methods of determining metal bond integrity

NASA Technical Reports Server (NTRS)

Malone, G. A.; Vecchies, L.; Wood, R.

1974-01-01

The capabilities and limitations of nondestructive evaluation methods were studied to detect and locate bond deficiencies in regeneratively cooled thrust chambers for rocket engines. Flat test panels and a cylinder were produced to simulate regeneratively cooled thrust chamber walls. Planned defects with various bond integrities were produced in the panels to evaluate the sensitivity, accuracy, and limitations of nondestructive methods to define and locate bond anomalies. Holography, acoustic emission, and ultrasonic scan were found to yield sufficient data to discern bond quality when used in combination and in selected sequences. Bonding techniques included electroforming and brazing. Materials of construction included electroformed nickel bonded to Nickel 200 and OFHC copper, electroformed copper bonded to OFHC copper, and 300 series stainless steel brazed to OFHC copper. Variations in outer wall strength, wall thickness, and defect size were evaluated for nondestructive test response.

Determination of relative ion chamber calibration coefficients from depth-ionization measurements in clinical electron beams

NASA Astrophysics Data System (ADS)

Muir, B. R.; McEwen, M. R.; Rogers, D. W. O.

2014-10-01

A method is presented to obtain ion chamber calibration coefficients relative to secondary standard reference chambers in electron beams using depth-ionization measurements. Results are obtained as a function of depth and average electron energy at depth in 4, 8, 12 and 18 MeV electron beams from the NRC Elekta Precise linac. The PTW Roos, Scanditronix NACP-02, PTW Advanced Markus and NE 2571 ion chambers are investigated. The challenges and limitations of the method are discussed. The proposed method produces useful data at shallow depths. At depths past the reference depth, small shifts in positioning or drifts in the incident beam energy affect the results, thereby providing a built-in test of incident electron energy drifts and/or chamber set-up. Polarity corrections for ion chambers as a function of average electron energy at depth agree with literature data. The proposed method produces results consistent with those obtained using the conventional calibration procedure while gaining much more information about the behavior of the ion chamber with similar data acquisition time. Measurement uncertainties in calibration coefficients obtained with this method are estimated to be less than 0.5%. These results open up the possibility of using depth-ionization measurements to yield chamber ratios which may be suitable for primary standards-level dissemination.

Technical note: Headspace analysis of explosive compounds using a novel sampling chamber.

PubMed

DeGreeff, Lauryn; Rogers, Duane A; Katilie, Christopher; Johnson, Kevin; Rose-Pehrsson, Susan

2015-03-01

The development of instruments and methods for explosive vapor detection is a continually evolving field of interest. A thorough understanding of the characteristic vapor signatures of explosive material is imperative for the development and testing of new and current detectors. In this research a headspace sampling chamber was designed to contain explosive materials for the controlled, reproducible sampling and characterization of vapors associated with these materials. In a detonation test, the chamber was shown to contain an explosion equivalent to three grams of trinitrotoluene (TNT) without damage to the chamber. The efficacy of the chamber in controlled headspace sampling was evaluated in laboratory tests with bulk explosive materials. Small quantities of TNT, triacetone triperoxide (TATP) and hexamethylene triperoxide diamine (HMTD) were separately placed in the sampling chamber, and the headspace of each material was analyzed by gas chromatography/mass spectrometry (GC/MS) with online cryogenic trapping to yield characteristic vapor signatures for each explosive compound. Chamber sampling conditions, temperature and sampling time, were varied to demonstrate suitability for precise headspace analysis. Published by Elsevier Ireland Ltd.

Characteristics Air Flow in Room Chamber Test Refrigerator Household Energy Consumption with Inlet Flow Variation

NASA Astrophysics Data System (ADS)

Susanto, Edy; Idrus Alhamid, M.; Nasruddin; Budihardjo

2018-03-01

Room Chamber is the most important in making a good Testing Laboratory. In this study, the 2-D modeling conducted to assess the effect placed the inlet on designing a test chamber room energy consumption of household refrigerators. Where the geometry room chamber is rectangular and approaching the enclosure conditions. Inlet varied over the side parallel to the outlet and compared to the inlet where the bottom is made. The purpose of this study was to determine and define the characteristics of the airflow in the room chamber using CFD simulation. CFD method is used to obtain flow characteristics in detail, in the form of vector flow velocity and temperature distribution inside the chamber room. The result found that the position of the inlet parallel to the outlet causes air flow cannot move freely to the side of the floor, even flow of air moves up toward the outlet. While by making the inlet is below, the air can move freely from the bottom up to the side of the chamber room wall as well as to help uniform flow.

Autoignition Chamber for Remote Testing of Pyrotechnic Devices

NASA Technical Reports Server (NTRS)

Harrington, Maureen L.; Steward, Gerald R.; Dartez, Toby W.

2009-01-01

The autoignition chamber (AIC) performs by remotely heating pyrotechnic devices that can fit the inner diameter of the tube furnace. Two methods, a cold start or a hot start, can be used with this device in autoignition testing of pyrotechnics. A cold start means extending a pyrotechnic device into the cold autoignition chamber and then heating the device until autoignition occurs. A hot start means heating the autoignition chamber to a specified temperature, and then extending the device into a hot autoignition chamber until autoignition occurs. Personnel are remote from the chamber during the extension into the hot chamber. The autoignition chamber, a commercially produced tubular furnace, has a 230-V, single-phase, 60-Hz electrical supply, with a total power output of 2,400 W. It has a 6-in. (15.2-cm) inner diameter, a 12-in. (30.4-cm) outer diameter and a 12-in.- long (30.4-cm), single-zone, solid tubular furnace (element) capable of heating to temperatures up to 2,012 F (1,100 C) in air.

Apparatus and method for fatigue testing of a material specimen in a high-pressure fluid environment

DOEpatents

Wang, Jy-An; Feng, Zhili; Anovitz, Lawrence M; Liu, Kenneth C

2013-06-04

The invention provides fatigue testing of a material specimen while the specimen is disposed in a high pressure fluid environment. A specimen is placed between receivers in an end cap of a vessel and a piston that is moveable within the vessel. Pressurized fluid is provided to compression and tension chambers defined between the piston and the vessel. When the pressure in the compression chamber is greater than the pressure in the tension chamber, the specimen is subjected to a compression force. When the pressure in the tension chamber is greater than the pressure in the compression chamber, the specimen is subjected to a tension force. While the specimen is subjected to either force, it is also surrounded by the pressurized fluid in the tension chamber. In some examples, the specimen is surrounded by hydrogen.

Apparatus and procedure to characterize the surface quality of conductors by measuring the rate of cathode emission as a function of surface electric field strength

DOEpatents

Mestayer, Mac; Christo, Steve; Taylor, Mark

2014-10-21

A device and method for characterizing quality of a conducting surface. The device including a gaseous ionizing chamber having centrally located inside the chamber a conducting sample to be tested to which a negative potential is applied, a plurality of anode or "sense" wires spaced regularly about the central test wire, a plurality of "field wires" at a negative potential are spaced regularly around the sense, and a plurality of "guard wires" at a positive potential are spaced regularly around the field wires in the chamber. The method utilizing the device to measure emission currents from the conductor.

Comparing the field and laboratory emission cell (FLEC) with traditional emissions testing chambers

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

Roache, N.F.; Guo, Z.; Fortmann, R.

1996-12-31

A series of tests was designed to evaluate the performance of the field and laboratory emission cell (FLEC) as applied to the testing of emissions from two indoor coating materials, floor wax and latex paint. These tests included validation of the repeatability of the test method, evaluation of the effect of different air velocities on source emissions, and a comparison of FLEC versus small chamber characterization of emissions. The FLEC exhibited good repeatability in characterization of emissions when applied to both sources under identical conditions. Tests with different air velocities showed significant effects on the emissions from latex paint, yetmore » little effect on emissions from the floor wax. Comparisons of data from the FLEC and small chamber show good correlation for measurements involving floor wax, but less favorable results for emissions from latex paint. The procedures and findings are discussed; conclusions are limited and include emphasis on the need for additional study and development of a standard method.« less

The thin-wall tube drift chamber operating in vacuum (prototype)

NASA Astrophysics Data System (ADS)

Alexeev, G. D.; Glonti, L. N.; Kekelidze, V. D.; Malyshev, V. L.; Piskun, A. A.; Potrbenikov, Yu. K.; Rodionov, V. K.; Samsonov, V. A.; Tokmenin, V. V.; Shkarovskiy, S. N.

2013-08-01

The goal of this work was to design drift tubes and a chamber operating in vacuum, and to develop technologies for tubes independent assembly and mounting in the chamber. These design and technology were tested on the prototype. The main features of the chamber are the following: the drift tubes are made of flexible mylar film (wall thickness 36 μm, diameter 9.80 mm, length 2160 mm) using ultrasonic welding along the generatrix; the welding device and methods were developed at JINR. Drift tubes with end plugs, anode wires and spacers were completely assembled outside the chamber. "Self-centering" spacers and bushes were used for precise setting of the anode wires and tubes. The assembled tubes were sealed with O-rings in their seats in the chamber which simplified the chamber assembling. Moreover the tube assembly and the chamber manufacture can be performed independently and in parallel; this sufficiently reduces the total time of chamber manufacture and assembling, its cost and allows tubes to be tested outside the chamber. The technology of independent tube assembling is suitable for a chamber of any shape but a round chamber is preferable for operation in vacuum. Single channel amplifier-discriminator boards which are more stable against cross talks were used for testing the tubes. Independently assembled tubes were mounted into the chamber prototype and its performance characteristic measured under the vacuum conditions. The results showed that both the structure and the tubes themselves normally operate. They are suitable for making a full-scale drift chamber for vacuum.

Fabrication of liquid-rocket thrust chambers by electroforming

NASA Technical Reports Server (NTRS)

Duscha, R. A.; Kazaroff, J. M.

1974-01-01

Electroforming has proven to be an excellent fabrication method for building liquid rocket regeneratively cooled thrust chambers. NASA sponsored technology programs have investigated both common and advanced methods. Using common procedures, several cooled spool pieces and thrust chambers have been made and successfully tested. The designs were made possible through the versatility of the electroforming procedure, which is not limited to simple geometric shapes. An advanced method of electroforming was used to produce a wire-wrapped, composite, pressure-loaded electroformed structure, which greatly increased the strength of the structure while still retaining the advantages of electroforming.

Atlas-Centaur Separation Test in the Space Power Chambers

NASA Image and Video Library

1963-11-21

An Atlas/Centaur mass model undergoes a separation test inside the Space Power Chambers at NASA Lewis Research Center. Lewis was in the midst of an extensive effort to prepare the Centaur second-stage rocket for its missions to send the Surveyor spacecraft to the moon as a precursor to the Apollo missions. As part of these preparations, Lewis management decided to convert its Altitude Wind Tunnel into two large test chambers—the Space Power Chambers. The conversion included the removal of the tunnel’s internal components and the insertion of bulkheads to seal off the new chambers within the tunnel. One chamber could simulate conditions found at 100 miles altitude, while this larger chamber simulated the upper atmosphere. In this test series, researchers wanted to verify that the vehicle’s retrorockets would properly separate the Centaur from the Atlas. The model was suspended horizontally on a trolley system inside chamber. A net was hung at one end to catch the jettisoned Atlas model. The chamber atmosphere was reduced to a pressure altitude of 100,000 feet, and high-speed cameras were synchronized to the ignition of the retrorockets. The simulated Centaur is seen here jettisoning from the Atlas out of view to the right. The study resulted in a new jettison method that would significantly reduce the separation time and thus minimize the danger of collision between the two stages during separation.

Iodine Beam Dump Design and Fabrication

NASA Technical Reports Server (NTRS)

Polzin, K. A.; Bradley, D. E.

2017-01-01

During the testing of electric thrusters, high-energy ions impacting the walls of a vacuum chamber can cause corrosion and/or sputtering of the wall materials, which can damage the chamber walls. The sputtering can also introduce the constituent materials of the chamber walls into an experiment, with those materials potentially migrating back to the test article and coating it with contaminants over time. The typical method employed in this situation is to install a beam dump fabricated from materials that have a lower sputter yield, thus reducing the amount of foreign material that could migrate towards the test article or deposit on anything else present in the vacuum facility.

Pretreatment of aqueous ammonia on oil palm empty fruit fiber (OPEFB) in production of sugar

NASA Astrophysics Data System (ADS)

Zulkiple, Nursyafiqah; Maskat, Mohamad Yusof; Hassan, Osman

2015-09-01

Oil Palm Empty Fruit Bunch (OPEFB) is an agricultural residue that has the potential to become a good source for renewable feedstock for production of sugar. This work evaluated the effectiveness of aqueous ammonia as pretreatment at low (soaking, SAA) and elevated temperature (pressurized chamber) to deconstruct the lignocellulosic feedstock, prior to enzymatic hydrolysis. The ammonia pretreatments were compared against the standard NaOH method. The best tested pressurized chamber method conditions were at 100°C with 3 hour retention time, 12.5% ammonium hydroxide and 1:30 solid loading. The digestibility of the feedstock is determined with enzymatic hydrolysis using Cellic Ctech2 and Cellic Htech2. The sugars produced by pressurized chamber method within 24 hour of enzyme hydrolysis are similar to that produced by NaOH method which is 439.90 mg/ml and 351.61 mg/ml, respectively. Compared with optimum SAA method (24 hour, 6.25% of ammonium hydroxide at room temperature), pressurized chamber method was capable of producing enhanced delignification and higher production of sugar upon hydrolysis. These findings were supported by the disappearance peak at 1732, 1512 and 1243 on Fourier Transform Infrared (FTIR spectrum) of treated OPEFB by pressurized chamber method. XRD determination showed reduced crystallinity of OPEFB (37.23%) after treatment by pressurized chamber, suggesting higher accessibility toward enzyme hydrolysis. The data obtained suggest that the pressurized chamber pre-treatment method are suitable for OPEFB deconstruction to produce high yield of sugar.

High-temperature strain cell for tomographic imaging

DOEpatents

MacDowell, Alastair A.; Nasiatka, James; Haboub, Abdel; Ritchie, Robert O.; Bale, Hrishikesh A.

2015-06-16

This disclosure provides systems, methods, and apparatus related to the high temperature mechanical testing of materials. In one aspect, a method includes providing an apparatus. The apparatus may include a chamber. The chamber may comprise a top portion and a bottom portion, with the top portion and the bottom portion each joined to a window material. A first cooled fixture and a second cooled fixture may be mounted to the chamber and configured to hold the sample in the chamber. A plurality of heating lamps may be mounted to the chamber and positioned to heat the sample. The sample may be placed in the first and the second cooled fixtures. The sample may be heated to a specific temperature using the heating lamps. Radiation may be directed though the window material, the radiation thereafter interacting with the sample and exiting the chamber through the window material.

In situ baking method for degassing of a kicker magnet in accelerator beam line

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

Kamiya, Junichiro, E-mail: kamiya.junichiro@jaea.go.jp; Ogiwara, Norio; Yanagibashi, Toru

In this study, the authors propose a new in situ degassing method by which only kicker magnets in the accelerator beam line are baked out without raising the temperature of the vacuum chamber to prevent unwanted thermal expansion of the chamber. By simply installing the heater and thermal radiation shield plates between the kicker magnet and the chamber wall, most of the heat flux from the heater directs toward the kicker magnet. The result of the verification test showed that each part of the kicker magnet was heated to above the target temperature with a small rise in the vacuummore » chamber temperature. A graphite heater was selected in this application to bake-out the kicker magnet in the beam line to ensure reliability and easy maintainability of the heater. The vacuum characteristics of graphite were suitable for heater operation in the beam line. A preliminary heat-up test conducted in the accelerator beam line also showed that each part of the kicker magnet was successfully heated and that thermal expansion of the chamber was negligibly small.« less

Dataset of Building and Environment Publication in 2016, A reference method for measuring emissions of SVOCs in small chambers

EPA Pesticide Factsheets

The data presented in this data file is a product of a journal publication. The dataset contains DEHP air concentrations in the emission test chamber.This dataset is associated with the following publication:Wu, Y., S. Cox, Y. Xu, Y. Liang, D. Wong, X. Liu, J. Benning, P. Clausen, Y. Zhang, C. Liu, and J. Little. A Reference Method for Measuring Emissions of SVOCs in Small Chambers. ENVIRONMENTAL SCIENCE & TECHNOLOGY. American Chemical Society, Washington, DC, USA, 95: 126-132, (2016).

Multistix 10 SG Leukocyte Esterage Dipstick Testing in Rapid Bedside Diagnosis of Spontaneous Bacterial Peritonitis: A Prospective Study.

PubMed

Jha, Ashish K; Kumawat, Dal C; Bolya, Yasvant K; Goenka, Mahesh K

2012-09-01

Spontaneous bacterial peritonitis (SBP) requires rapid diagnosis and the initiation of antibiotics. Diagnosis of SBP is usually based on cytobacteriological examination of ascitic fluid. These tests require good laboratory facilities and reporting time of few hours to 1-2 day. However, the 24 h laboratory facilities not widely available in country like India. We evaluated the diagnostic utility of reagent strip (Multistix 10 SG(®)) for rapid diagnosis of SBP. The study was prospectively carried out on patients of cirrhosis with ascites. Bedside leukocyte esterase reagent strip testing was performed on ascitic fluid. Cell count as determined by colorimetric scale of reagent strip was compared with counting chamber method. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were calculated. Out of 100 patients with cirrhotic ascites, [72 males: 28 female; mean age 44.34 (SD 13.03) years] 18 patients were diagnosed to have SBP by counting chamber method as compared to 14 patients detected to have SBP by reagent strip test ≥++ positive. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of reagent strip ≥++ positive were 77.77%, 95.12%, 77.77%, 95.12% and 92% respectively compared to counting chamber method. Reagent strip to diagnose SBP is very specific but less sensitive as compared to counting chamber method. This can be performed rapidly, easily and efficiently even in remote area of developing countries. This bedside test could be a useful tool for the diagnosis of SBP in country like India.

Evaluation of Impinging Stream Vortex Chamber Concepts for Liquid Rocket Engine Applications

NASA Technical Reports Server (NTRS)

Trinh, Huu P.; Bullard, Brad; Kopicz, Charles; Michaels, Scott; Turner, James (Technical Monitor)

2001-01-01

To pursue technology developments for future launch vehicles, NASA/Marshall Space Flight Center (MSFC) is examining vortex chamber concepts for liquid rocket engine applications. Past studies indicated that the vortex chamber schemes potentially have a number of advantages over conventional chamber methods. Due to the nature of the vortex flow, relatively cooler propellant streams tend to flow along the chamber wall. Hence, the thruster chamber can be operated without the need of any cooling techniques. This vortex flow also creates strong turbulence, which promotes the propellant mixing process. Consequently, the subject chamber concepts not only offer the system simplicity, but they also would enhance the combustion performance. The test results showed that the chamber performance was markedly high even at a low chamber length-to-diameter ratio (L/D). This incentive can be translated to a convenience in the thrust chamber packaging. Variations of the vortex chamber concepts have been introduced in the past few decades. These investigations include an ongoing work at Orbital Technologies Corporation (ORBITEC). By injecting the oxidizer tangentially at the chamber convergence and fuel axially at the chamber head end, Knuth et al. were able to keep the wall relatively cold. A recent investigation of the low L/D vortex chamber concept for gel propellants was conducted by Michaels. He used both triplet (two oxidizer and one fuel orifices) and unlike impinging schemes to inject propellants tangentially along the chamber wall. Michaels called the subject injection scheme as Impinging Stream Vortex Chamber (ISVC). His preliminary tests showed that high performance, with an Isp efficiency of 92%, can be obtained. MSFC and the U.S. Army are jointly investigating an application of the ISVC concept for the cryogenic oxygen/hydrocarbon propellant system. This vortex chamber concept is currently tested with gel propellants at AMCOM at Redstone Arsenal, Alabama. A version of this concept for the liquid oxygen (LOX)/hydrocarbon fuel (RPM) system has been derived from the one for the gel propellant.

Status on Technology Development of Optic Fiber-Coupled Laser Ignition System for Rocket Engine Applications

NASA Technical Reports Server (NTRS)

Trinh, Huu P.; Early, Jim; Osborne, Robin; Thomas, Matthew; Bossard, John

2003-01-01

To pursue technology developments for future launch vehicles, NASA/Marshall Space Flight Center (MSFC) is examining vortex chamber concepts for liquid rocket engine applications. Past studies indicated that the vortex chamber schemes potentially have a number of advantages over conventional chamber methods. Due to the nature of the vortex flow, relatively cooler propellant streams tend to flow along the chamber wall. Hence, the thruster chamber can be operated without the need of any cooling techniques. This vortex flow also creates strong turbulence, which promotes the propellant mixing process. Consequently, the subject chamber concept: not only offer system simplicity, but also enhance the combustion performance. Test results have shown that chamber performance is markedly high even at a low chamber length-to-diameter ratio. This incentive can be translated to a convenience in the thrust chamber packaging.

Evaluation of Visibility Sensors at the Eglin Air Force Base Climatic Chamber

DOT National Transportation Integrated Search

1983-10-01

Three transmissometers and five forward-scatter meters were evaluated for measuring fog, haze, rain and snow in the large test chamber of the Eglin Air Force Base Climatic Laboratory. Methods were developed for generating moderately uniform and stabl...

24 CFR 3280.406 - Air chamber test method for certification and qualification of formaldehyde emission levels.

Code of Federal Regulations, 2010 CFR

2010-04-01

... particleboard is produced or surface-finished, whichever is later, the panels must be dead-stacked or air-tight... with the Standard Test Method for Determining Formaldehyde Levels from Wood Products Under Defined Test...

Vitrigel-eye irritancy test method using HCE-T cells.

PubMed

Yamaguchi, Hiroyuki; Kojima, Hajime; Takezawa, Toshiaki

2013-10-01

We previously reported that the time-dependent relative changes of transepithelial electrical resistance (TEER) after exposing four different chemicals to a human corneal epithelium (HCE) model were well correlated to the potential of ocular irritancy. Meanwhile, we recently developed a collagen vitrigel membrane (CVM) chamber possessing a scaffold composed of high-density collagen fibrils equivalent to connective tissues in vivo as a three-dimensional culture tool. The CVM chamber is useful for biomedical assays and immunohistology using cryosections that are inappropriate to be performed using the conventional Millicell chamber with a polyethylene terephthalate membrane. In this study, we aimed to develop a new eye irritancy test (EIT) method called "Vitrigel-EIT method" that can facilitate to briefly and accurately estimate the widespread irritancy of test chemicals by applying the TEER assay system to a HCE model fabricated in the CVM chamber. HCE-T cells (a HCE-derived cell strain) were cultured in the CVM chamber for 6 days, and consequently, the Vitrigel-HCE model possessing the following characteristics of HCE in vivo was formed: six cell layers with specific protein expressions and their barrier function. Time-dependent profiles of TEER values after exposing 30 test chemicals to the HCE model were converted into the scores of three indexes (time lag, intensity, and plateau level), and each chemical was successfully classified into irritant or nonirritant category by utilizing the criteria for the indexes, resulting in the excellent correlation with Globally Harmonized System of Classification and Labelling of Chemicals (GHS) classification (sensitivity: 100%, specificity: 75%, accuracy: 90%). These data suggest that the widespread eye irritancy of chemicals can be predicted without false negatives by the Vitrigel-EIT method. Interestingly, the disruption of tight junctions was immunohistologically observed after exposing not only irritants but also three compounds classified as nonirritant by GHS but found positive in our Vitrigel-EIT method confirming a possible mild irritant property.

INDOOR AIR EMISSIONS FROM OFFICE EQUIPMENT: TEST METHOD DEVELOPMENT AND POLLUTION PREVENTION OPPORTUNITIES

EPA Science Inventory

The report describes the development and evaluation of a large chamber test method for measuring emissions from dry-process photocopiers. The test method was developed in two phases. Phase 1 was a single-laboratory evaluation at Research Triangle Institute (RTI) using four, mid-r...

A comparison of methods for estimating open-water evaporation in small wetlands

USGS Publications Warehouse

Masoner, Jason R.; Stannard, David I.

2010-01-01

We compared evaporation measurements from a floating pan, land pan, chamber, and the Priestley-Taylor (PT) equation. Floating pan, land pan, and meteorological data were collected from June 6 to July 21, 2005, at a small wetland in the Canadian River alluvium in central Oklahoma, USA. Evaporation measured with the floating pan compared favorably to 12 h chamber measurements. Differences between chamber and floating pan rates ranged from −0.2 to 0.3 mm, mean of 0.1 mm. The difference between chamber and land pan rates ranged from 0.8 to 2.0 mm, mean of 1.5 mm. The mean chamber-to-floating pan ratio was 0.97 and the mean chamber-to-land pan ratio was 0.73. The chamber-to-floating pan ratio of 0.97 indicates the use of a floating pan to measure evaporation in small limited-fetch water bodies is an appropriate and accurate method for the site investigated. One-sided Paired t-Tests indicate daily floating pan rates were significantly less than land pan and PT rates. A two-sided Paired t-Test indicated there was no significant difference between land pan and PT values. The PT equation tends to overestimate evaporation during times when the air is of low drying power and tends to underestimate as drying power increases.

Apparatus and method for excluding gas from a liquid

DOEpatents

Murphy, Jr., Robert J.

1985-01-01

The present invention is directed to an apparatus and method for preventing diffusion of a gas under high pressure into the bulk of a liquid filling a substantially closed chamber. This apparatus and method is particularly useful in connection with test devices for testing fluid characteristics under harsh conditions of extremely high pressure and high temperature. These devices typically pressurize the liquid by placing the liquid in pressure and fluid communication with a high pressure inert gas. The apparatus and method of the present invention prevent diffusion of the pressurizing gas into the bulk of the test liquid by decreasing the chamber volume at a rate sufficient to maintain the bulk of the liquid free of absorbed or dissolved gas by expelling that portion of the liquid which is contaminated by the pressurizing gas.

Evaluation of Impinging Stream Vortex Chamber Concepts for Liquid Rocket Engine Applications

NASA Technical Reports Server (NTRS)

Trinh, Huu P.; Bullard, Brad; Kopicz, Charles; Michaels, Scott

2002-01-01

To pursue technology developments for future launch vehicles, NASA/Marshall Space Flight Center (MSFC) is examining vortex chamber concepts for liquid rocket engine applications. Past studies indicated that the vortex chamber schemes potentially have a number of advantages over conventional chamber methods. Due to the nature of the vortex flow, relatively cooler propellant streams tend to flow along the chamber wall. Hence, the thruster chamber can be operated without the need of any cooling techniques. This vortex flow also creates strong turbulence, which promotes the propellant mixing process. Consequently, the subject chamber concepts not only offer system simplicity, but also enhance the combustion performance. Test results have shown that chamber performance is markedly high even at a low chamber length-to-diameter ratio (LD). This incentive can be translated to a convenience in the thrust chamber packaging. Variations of the vortex chamber concepts have been introduced in the past few decades. These investigations include an ongoing work at Orbital Technologies Corporation (ORBITEC). By injecting the oxidizer tangentially at the chamber convergence and fuel axially at the chamber head end, Knuth et al. were able to keep the wall relatively cold. A recent investigation of the low L/D vortex chamber concept for gel propellants was conducted by Michaels. He used both triplet (two oxidizer orifices and one fuel orifice) and unlike impinging schemes to inject propellants tangentially along the chamber wall. Michaels called the subject injection scheme an Impinging Stream Vortex Chamber (ISVC). His preliminary tests showed that high performance, with an Isp efficiency of 9295, can be obtained. MSFC and the U. S. Army are jointly investigating an application of the ISVC concept for the cryogenic oxygen/hydrocarbon propellant system. This vortex chamber concept is currently tested with gel propellants at AMCOM at Redstone Arsenal, Alabama. A version of this concept for the liquid oxygen (LOX) hydrocarbon fuel (RP-1) system has been derived from the one for the gel propellant. An unlike impinging injector was employed to deliver the propellants to the chamber. MSFC is also conducting an alternative injection scheme, called the chasing injector, associated with this vortex chamber concept. In this injection technique, both propellant jets and their impingement point are in the same chamber cross-sectional plane. Long duration tests (approximately up to 15 seconds) will be conducted on the ISVC to study the thermal effects. This paper will report the progress of the subject efforts at NASA Marshall Space Flight Center. Thrust chamber performance and thermal wall compatibility will be evaluated. The chamber pressures, wall temperatures, and thrust will be measured as appropriate. The test data will be used to validate CFD models, which, in turn, will be used to design the optimum vortex chambers. Measurements in the previous tests showed that the chamber pressures vary significantly with radius. This is due to the existence of the vortices in the chamber flow field. Hence, the combustion efficiency may not be easily determined from chamber pressure. For this project, measured thrust data will be collected. The performance comparison will be in terms of specific impulse efficiencies. In addition to the thrust measurements, several pressure and temperature readings at various locations on the chamber head faceplate and the chamber wall will be made. The first injector and chamber were designed and fabricated based on the available data and experience gained during gel propellant system tests by the U.S. Army. The alternate injector for the ISVC was also fabricated. Hot-fire tests of the vortex chamber are about to start and are expected to complete in February of 2003 at the TS115 facility of MSFC.

Simplified Method for the Characterization of Rectangular Straw Bales (RSB) Thermal Conductivity

NASA Astrophysics Data System (ADS)

Conti, Leonardo; Goli, Giacomo; Monti, Massimo; Pellegrini, Paolo; Rossi, Giuseppe; Barbari, Matteo

2017-10-01

This research aims to design and implement tools and methods focused at the assessment of the thermal properties of full size Rectangular Straw Bales (RSB) of various nature and origin, because their thermal behaviour is one of the key topics in market development of sustainable building materials. As a first approach a method based on a Hot-Box in agreement with the ASTM C1363 - 11 standard was adopted. This method was found to be difficult for the accurate measurement of energy flows. Instead, a method based on a constant energy input was developed. With this approach the thermal conductivity of a Rectangular Straw-Bale (RSB λ) can be determined by knowing the thermal conductivity of the materials used to build the chamber and the internal and external temperature of the samples and of the chamber. A measurement a metering chamber was built and placed inside a climate chamber, maintained at constant temperature. A known quantity of energy was introduced inside the metering chamber. A series of thermopiles detects the temperature of the internal and external surfaces of the metering chamber and of the specimens allowing to calculate the thermal conductivity of RSB in its natural shape. Different cereal samples were tested. The values were found consistent with those published in scientific literature.

Simultaneous optimization method for absorption spectroscopy postprocessing.

PubMed

Simms, Jean M; An, Xinliang; Brittelle, Mack S; Ramesh, Varun; Ghandhi, Jaal B; Sanders, Scott T

2015-05-10

A simultaneous optimization method is proposed for absorption spectroscopy postprocessing. This method is particularly useful for thermometry measurements based on congested spectra, as commonly encountered in combustion applications of H2O absorption spectroscopy. A comparison test demonstrated that the simultaneous optimization method had greater accuracy, greater precision, and was more user-independent than the common step-wise postprocessing method previously used by the authors. The simultaneous optimization method was also used to process experimental data from an environmental chamber and a constant volume combustion chamber, producing results with errors on the order of only 1%.

Altitude Chamber Testing of the Passenger Oxygen System (POS)

DTIC Science & Technology

2009-08-01

4 5.0 Schedule 4 6.0 Method for Unmanned Testing 4 7.0 Unmanned Testing Results 6 8.0 Methods for Manned...manned testing. 30 Mar 09: Subjects received orientation and training briefings. 31 Mar-03 Apr 09: POS manned testing conducted. 6.0 Method ...8.0 Methods for Manned Testing: The system was tested in five manned modes. The details of each mode are described in Appendix B (ICD for

Implementation of Leak Test Methods for the International Space Station (ISS) Elements, Systems and Components

NASA Technical Reports Server (NTRS)

Underwood, Steve; Lvovsky, Oleg

2007-01-01

The International Space Station (ISS has Qualification and Acceptance Environmental Test Requirements document, SSP 41172 that includes many environmental tests such as Thermal vacuum & Cycling, Depress/Repress, Sinusoidal, Random, and Acoustic Vibration, Pyro Shock, Acceleration, Humidity, Pressure, Electromatic Interference (EMI)/Electromagnetic Compatibility (EMCO), etc. This document also includes (13) leak test methods for Pressure Integrity Verification of the ISS Elements, Systems, and Components. These leak test methods are well known, however, the test procedure for specific leak test method shall be written and implemented paying attention to the important procedural steps/details that, if omitted or deviated, could impact the quality of the final product and affect the crew safety. Such procedural steps/details for different methods include, but not limited to: - Sequence of testing, f or example, pressurization and submersion steps for Method I (Immersion); - Stabilization of the mass spectrometer leak detector outputs fo r Method II (vacuum Chamber or Bell jar); - Proper data processing an d taking a conservative approach while making predictions for on-orbit leakage rate for Method III(Pressure Change); - Proper Calibration o f the mass spectrometer leak detector for all the tracer gas (mostly Helium) Methods such as Method V (Detector Probe), Method VI (Hood), Method VII (Tracer Probe), Method VIII(Accumulation); - Usage of visibl ility aides for Method I (Immersion), Method IV (Chemical Indicator), Method XII (Foam/Liquid Application), and Method XIII (Hydrostatic/Visual Inspection); While some methods could be used for the total leaka ge (either internal-to-external or external-to-internal) rate requirement verification (Vacuum Chamber, Pressure Decay, Hood, Accumulation), other methods shall be used only as a pass/fail test for individual joints (e.g., welds, fittings, and plugs) or for troubleshooting purposes (Chemical Indicator, Detector Probe, Tracer Probe, Local Vacuum Chamber, Foam/Liquid Application, and Hydrostatic/Visual Inspection). Any isolation of SSP 41172 requirements have led to either retesting of hardware or accepting a risk associated with the potential system or component pressure integrity problem during flight.

KSC-04pd1386

NASA Image and Video Library

2004-06-17

KENNEDY SPACE CENTER, FLA. - James E. Fesmire (right), NASA lead engineer for the KSC Cryogenics Testbed, works on Cryostat-1, the Methods of Testing Thermal Insulation and Association Test Apparatus, which he developed. At left is co-inventor Dr. Stan Augustynowicz, chief scientist with Sierra Lobo Inc. in Milan, Ohio. Cryostat-1 provides absolute thermal performance values of cryogenic insulation systems under real-world conditions. Cryogenic liquid is supplied to a test chamber and two guard chambers, and temperatures are sensed within the vacuum chamber to test aerogels, foams or other materials. The Cryostat-1 machine can detect the absolute heat leakage rates through materials under the full range of vacuum conditions. Fesmire recently acquired three patents for testing thermal insulation materials for cryogenic systems. The research team of the Cryogenics Testbed offers testing and support for a number of programs and initiatives for NASA and commercial customers.

KSC-04pd1387

NASA Image and Video Library

2004-06-17

KENNEDY SPACE CENTER, FLA. - James E. Fesmire (right), NASA lead engineer for the KSC Cryogenics Testbed, works on Cryostat-1, the Methods of Testing Thermal Insulation and Association Test Apparatus, which he developed. At left is co-inventor Dr. Stan Augustynowicz, chief scientist with Sierra Lobo Inc. in Milan, Ohio. Cryostat-1 provides absolute thermal performance values of cryogenic insulation systems under real-world conditions. Cryogenic liquid is supplied to a test chamber and two guard chambers, and temperatures are sensed within the vacuum chamber to test aerogels, foams or other materials. The Cryostat-1 machine can detect the absolute heat leakage rates through materials under the full range of vacuum conditions. Fesmire recently acquired three patents for testing thermal insulation materials for cryogenic systems. The research team of the Cryogenics Testbed offers testing and support for a number of programs and initiatives for NASA and commercial customers.

Space simulation facilities providing a stable thermal vacuum facility

NASA Technical Reports Server (NTRS)

Tellalian, Martin L.

1990-01-01

CBI has recently constructed the Intermediate Thermal Vacuum Facility. Built as a corporate facility, the installation will first be used on the Boost Surveillance and Tracking System (BSTS) program. It will also be used to develop and test other sensor systems. The horizontal chamber has a horseshoe shaped cross section and is supported on pneumatic isolators for vibration isolation. The chamber structure was designed to meet stability and stiffness requirements. The design process included measurement of the ambient ground vibrations, analysis of various foundation test article support configurations, design and analysis of the chamber shell and modal testing of the chamber shell. A detailed 3-D finite element analysis was made in the design stage to predict the lowest three natural frequencies and mode shapes and to identify local vibrating components. The design process is described and the results are compared of the finite element analysis to the results of the field modal testing and analysis for the 3 lowest natural frequencies and mode shapes. Concepts are also presented for stiffening large steel structures along with methods to improve test article stability in large space simulation facilities.

Small-Chamber Measurements of Chemical-Specific Emission Factors for Drywall

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

Maddalena, Randy; Russell, Marion; Apte, Michael G.

2010-06-01

Imported drywall installed in U.S. homes is suspected of being a source of odorous and potentially corrosive indoor pollutants. To support an investigation of those building materials by the Consumer Products Safety Commission (CPSC), Lawrence Berkeley National Laboratory (LBNL) measured chemical-specific emission factors for 30 samples of drywall materials. Emission factors are reported for 75 chemicals and 30 different drywall samples encompassing both domestic and imported stock and incorporating natural, synthetic, or mixed gypsum core material. CPSC supplied all drywall materials. First the drywall samples were isolated and conditioned in dedicated chambers, then they were transferred to small chambers wheremore » emission testing was performed. Four sampling and analysis methods were utilized to assess (1) volatile organic compounds, (2) low molecular weight carbonyls, (3) volatile sulfur compounds, and (4) reactive sulfur gases. LBNL developed a new method that combines the use of solid phase microextraction (SPME) with small emission chambers to measure the reactive sulfur gases, then extended that technique to measure the full suite of volatile sulfur compounds. The testing procedure and analysis methods are described in detail herein. Emission factors were measured under a single set of controlled environmental conditions. The results are compared graphically for each method and in detailed tables for use in estimating indoor exposure concentrations.« less

Standardizing the Delivery of 20 μL of Hapten During Patch Testing.

PubMed

Selvick, Annika; Stauss, Kari; Strobush, Katrina; Taylor, Lauren; Picard, Alexandra; Doll, Andrea; Reeder, Margo

2016-01-01

The current method for patch test tray assembly requires hand dispensing a small volume of hapten onto chambers. Because of human error, this technique produces inaccurate and inconsistent results. The recommended volume of hapten for patch testing using Finn Chambers is 20 μL. The aims of this study were to create a device that standardizes the delivery of 20 μL and to compare it with the current hand dispensing technique. A device, named the Revolution, was created using the SolidWorks program. Five nurses in our Contact Dermatitis Clinic were asked to load 10 Finn Chambers using the current technique and also using the Revolution. Assembly time, volume of petrolatum, and accuracy of placement were measured. After the 3 trials, the nurses completed a survey on the 2 methods. The amount of petrolatum dispensed using the current technique ranged from 16 to 85 μL, with an average amount of 41.39 μL. The Revolution design dispensed an average of 19.78 μL. The current hand dispensing technique does not allow for accurate and consistent dispensing of 20 μL for patch testing. In contrast, the Revolution is an accurate and consistent device that can help standardize the patch testing method.

Improvement of Thermal Interruption Capability in Self-blast Interrupting Chamber for New 245kV-50kA GCB

NASA Astrophysics Data System (ADS)

Shinkai, Takeshi; Koshiduka, Tadashi; Mori, Tadashi; Uchii, Toshiyuki; Tanaka, Tsutomu; Ikeda, Hisatoshi

Current zero measurements are performed for 245kV-50kA-60Hz short line fault (L90) interruption tests with a self-blast interrupting chamber (double volume system) which has the interrupting capability up to 245kV-50kA-50Hz L90. Lower L90 interruption capability is observed for longer arcing time although very high pressure rise is obtained. It may be caused by higher blowing temperature and lower blowing density for longer arcing time. Interruption criteria and a optimization method of the chamber design are discussed to improve L90 interruption capability with it. The new chambers are designed at 245kV-50kA-60Hz to improve gas density in thermal volume for long arcing time. 245kV-50kA-60Hz L90 interruptions are performed with the new chamber. The suggested optimization method is an efficient tool for the self-blast interrupting chamber design although study of computing methods is required to calculate arc conductance around current zero as a direct criterion for L90 interruption capability with higher accuracy.

Validation of analytical methods in GMP: the disposable Fast Read 102® device, an alternative practical approach for cell counting.

PubMed

Gunetti, Monica; Castiglia, Sara; Rustichelli, Deborah; Mareschi, Katia; Sanavio, Fiorella; Muraro, Michela; Signorino, Elena; Castello, Laura; Ferrero, Ivana; Fagioli, Franca

2012-05-31

The quality and safety of advanced therapy products must be maintained throughout their production and quality control cycle to ensure their final use in patients. We validated the cell count method according to the International Conference on Harmonization of Technical Requirements for Registration of Pharmaceuticals for Human Use and European Pharmacopoeia, considering the tests' accuracy, precision, repeatability, linearity and range. As the cell count is a potency test, we checked accuracy, precision, and linearity, according to ICH Q2. Briefly our experimental approach was first to evaluate the accuracy of Fast Read 102® compared to the Bürker chamber. Once the accuracy of the alternative method was demonstrated, we checked the precision and linearity test only using Fast Read 102®. The data were statistically analyzed by average, standard deviation and coefficient of variation percentages inter and intra operator. All the tests performed met the established acceptance criteria of a coefficient of variation of less than ten percent. For the cell count, the precision reached by each operator had a coefficient of variation of less than ten percent (total cells) and under five percent (viable cells). The best range of dilution, to obtain a slope line value very similar to 1, was between 1:8 and 1:128. Our data demonstrated that the Fast Read 102® count method is accurate, precise and ensures the linearity of the results obtained in a range of cell dilution. Under our standard method procedures, this assay may thus be considered a good quality control method for the cell count as a batch release quality control test. Moreover, the Fast Read 102® chamber is a plastic, disposable device that allows a number of samples to be counted in the same chamber. Last but not least, it overcomes the problem of chamber washing after use and so allows a cell count in a clean environment such as that in a Cell Factory. In a good manufacturing practice setting the disposable cell counting devices will allow a single use of the count chamber they can then be thrown away, thus avoiding the waste disposal of vital dye (e.g. Trypan Blue) or lysing solution (e.g. Tuerk solution).

Large Scale Flame Spread Environmental Characterization Testing

NASA Technical Reports Server (NTRS)

Clayman, Lauren K.; Olson, Sandra L.; Gokoghi, Suleyman A.; Brooker, John E.; Ferkul, Paul V.; Kacher, Henry F.

2013-01-01

Under the Advanced Exploration Systems (AES) Spacecraft Fire Safety Demonstration Project (SFSDP), as a risk mitigation activity in support of the development of a large-scale fire demonstration experiment in microgravity, flame-spread tests were conducted in normal gravity on thin, cellulose-based fuels in a sealed chamber. The primary objective of the tests was to measure pressure rise in a chamber as sample material, burning direction (upward/downward), total heat release, heat release rate, and heat loss mechanisms were varied between tests. A Design of Experiments (DOE) method was imposed to produce an array of tests from a fixed set of constraints and a coupled response model was developed. Supplementary tests were run without experimental design to additionally vary select parameters such as initial chamber pressure. The starting chamber pressure for each test was set below atmospheric to prevent chamber overpressure. Bottom ignition, or upward propagating burns, produced rapid acceleratory turbulent flame spread. Pressure rise in the chamber increases as the amount of fuel burned increases mainly because of the larger amount of heat generation and, to a much smaller extent, due to the increase in gaseous number of moles. Top ignition, or downward propagating burns, produced a steady flame spread with a very small flat flame across the burning edge. Steady-state pressure is achieved during downward flame spread as the pressure rises and plateaus. This indicates that the heat generation by the flame matches the heat loss to surroundings during the longer, slower downward burns. One heat loss mechanism included mounting a heat exchanger directly above the burning sample in the path of the plume to act as a heat sink and more efficiently dissipate the heat due to the combustion event. This proved an effective means for chamber overpressure mitigation for those tests producing the most total heat release and thusly was determined to be a feasible mitigation strategy to incorporate into the microgravity experiment.

Design of a hydraulic analog of the circulatory system for evaluating artificial hearts.

PubMed

Donovan, F M

1975-01-01

A major problem in improving artificial heart designs is the absence of methods for accurate in vitro testing of artificial heart systems. A mock circulatory system has been constructed which hydraulically simulates the systemic and pulmonary circulations of the normal human. The device is constructed of 1/2 in. acrylic sheet and has overall dimensions of 24 in. wide, 16 in. tall, and 8 in. deep. The artificial heart to be tested is attached to the front of the device, and pumps fluid from the systemic venous chamber into the pulmonary arterial chamber and from the pulmonary venous chamber into the systemic arterial chamber. Each of the four chambers is hermetically sealed. The compliance of each chamber is determined by the volume of air trapped above the fluid in that chamber. The pulmonary and systemic resistances are set automatically by bellows-operated valves to simulate the barroreceptor response in the systemic arteries and the passive pulmonary resistance response in the pulmonary arteries. Cardiac output is measured by a turbine flowmeter in the systemic circulation. Results using the Kwan-Gett artificial heart show a good comparison between the mock circulatory system response and the calf response.

An Experimental Study of Upward Burning Over Long Solid Fuels: Facility Development and Comparison

NASA Technical Reports Server (NTRS)

Kleinhenz, Julie; Yuan, Zeng-Guang

2011-01-01

As NASA's mission evolves, new spacecraft and habitat environments necessitate expanded study of materials flammability. Most of the upward burning tests to date, including the NASA standard material screening method NASA-STD-6001, have been conducted in small chambers where the flame often terminates before a steady state flame is established. In real environments, the same limitations may not be present. The use of long fuel samples would allow the flames to proceed in an unhindered manner. In order to explore sample size and chamber size effects, two large chambers were developed at NASA GRC under the Flame Prevention, Detection and Suppression (FPDS) project. The first was an existing vacuum facility, VF-13, located at NASA John Glenn Research Center. This 6350 liter chamber could accommodate fuels sample lengths up to 2 m. However, operational costs and restricted accessibility limited the test program, so a second laboratory scale facility was developed in parallel. By stacking additional two chambers on top of an existing combustion chamber facility, this 81 liter Stacked-chamber facility could accommodate a 1.5 m sample length. The larger volume, more ideal environment of VF-13 was used to obtain baseline data for comparison with the stacked chamber facility. In this way, the stacked chamber facility was intended for long term testing, with VF-13 as the proving ground. Four different solid fuels (adding machine paper, poster paper, PMMA plates, and Nomex fabric) were tested with fuel sample lengths up to 2 m. For thin samples (papers) with widths up to 5 cm, the flame reached a steady state length, which demonstrates that flame length may be stabilized even when the edge effects are reduced. For the thick PMMA plates, flames reached lengths up to 70 cm but were highly energetic and restricted by oxygen depletion. Tests with the Nomex fabric confirmed that the cyclic flame phenomena, observed in small facility tests, continued over longer sample. New features were also observed at the higher oxygen/pressure conditions available in the large chamber. Comparison of flame behavior between the two facilities under identical conditions revealed disparities, both qualitative and quantitative. This suggests that, in certain ranges of controlling parameters, chamber size and shape could be one of the parameters that affect the material flammability. If this proves to be true, it may limit the applicability of existing flammability data.

Construction and test of new precision drift-tube chambers for the ATLAS muon spectrometer

NASA Astrophysics Data System (ADS)

Kroha, H.; Kortner, O.; Schmidt-Sommerfeld, K.; Takasugi, E.

2017-02-01

ATLAS muon detector upgrades aim for increased acceptance for muon triggering and precision tracking and for improved rate capability of the muon chambers in the high-background regions of the detector with increasing LHC luminosity. The small-diameter Muon Drift Tube (sMDT) chambers have been developed for these purposes. With half of the drift-tube diameter of the MDT chambers and otherwise unchanged operating parameters, sMDT chambers share the advantages of the MDTs, but have an order of magnitude higher rate capability and can be installed in detector regions where MDT chambers do not fit in. The chamber assembly methods have been optimized for mass production, minimizing construction time and personnel. Sense wire positioning accuracies of 5 μm have been achieved in serial production for large-size chambers comprising several hundred drift tubes. The construction of new sMDT chambers for installation in the 2016/17 winter shutdown of the LHC and the design of sMDT chambers in combination with new RPC trigger chambers for replacement of the inner layer of the barrel muon spectrometer are in progress.

Testing the performance of dosimetry measurement standards for calibrating area and personnel dosimeters

NASA Astrophysics Data System (ADS)

Walwyn-Salas, G.; Czap, L.; Gomola, I.; Tamayo-García, J. A.

2016-07-01

The cylindrical NE2575 and spherical PTW32002 chamber types were tested in this paper to determine their performance at different source-chamber distances, field sizes and two radiation qualities. To ensure an accurate measurement, there is a need to apply a correction factor to NE2575 measurements at different distances because of differences found between the reference point defined by the manufacturer and the effective point of measurements. This correction factor for NE2575 secondary standard from the Center for Radiation Protection and Hygiene of Cuba was assessed with a 0.3% uncertainty using the results of three methods. Those laboratories that use the NE2575 chambers should take into consideration the performance characteristics tested in this paper to obtain accurate measurements.

Liquid fluorine/hydrazine rhenium thruster update

NASA Technical Reports Server (NTRS)

Appel, M. A.; Kaplan, R. B.; Tuffias, R. H.

1983-01-01

The status of a fluorine/hydrazine thruster development program is discussed. A solid rhenium metal sea-level thrust chamber was successfully fabricated and tested for a total run duration of 1075 s with 17 starts. Rhenium fabrication methods are discussed. A test program was conducted to evaluate performance and chamber cooling. Acceptable performance was reached and cooling was adequate. A flight-type injector was fabricated that achieved an average extrapolated performance value of 3608 N-s/kg (368 lbf-s/lbm). Altitude thrust chambers were fabricated. One chamber incorporates a rhenium combustor and nozzle with an area ratio of 15:1, and a columbium nozzle extension with area ratios from 15:1 to 60:1. The other chamber was fabricated completely with a carbon/carbon composite. Because of the attributes of rhenium for use in high-temperature applications, a program to provide the materials and processes technology needed to reliably fabricate and/or repair vapor-deposited rhenium parts of relatively large size and complex shape is recommended.

Effect of a newly developed charging chamber for the treatment of hypotension during hemodialysis.

PubMed

Ikegami, Tadayoshi; Fujii, Zenzo; Minami, Masae; Matsumoto, Machiko; Matsuzaki, Masunori

2006-01-01

We developed a new method of hemodialysis using a charging chamber for treatment of hemodialysis patients with hypotension occurring during the latter half of hemodialysis (collapse). The purpose of this method was to recover systolic blood pressure (BP) by returning a part of blood within the chamber into the body circulation when hemodialysis collapse occurred. Using this method, systolic BP recovery (DeltaBP) in ten hemodialysis patients (4 males, 6 females, mean age 66.0 years old) was compared to a control group treated with intravenous administration of 20 ml of 10% NaCl. When hemodialysis collapse occurred, 60 ml of blood within the chamber in this method and 20 ml of 10% NaCl intravenously in the control group were administered and systolic BP was measured 20 minutes later. The results showed that DeltaBP using this method was 26.0 mm Hg (ANOVA: p = 0.0072), while in the control group it was 30.2 mm Hg (ANOVA: p = 0.0003), and there was no significant difference between the systolic BP recovery of both groups (paired t test: p = 0.4196).

Validation of analytical methods in GMP: the disposable Fast Read 102® device, an alternative practical approach for cell counting

PubMed Central

2012-01-01

Background The quality and safety of advanced therapy products must be maintained throughout their production and quality control cycle to ensure their final use in patients. We validated the cell count method according to the International Conference on Harmonization of Technical Requirements for Registration of Pharmaceuticals for Human Use and European Pharmacopoeia, considering the tests’ accuracy, precision, repeatability, linearity and range. Methods As the cell count is a potency test, we checked accuracy, precision, and linearity, according to ICH Q2. Briefly our experimental approach was first to evaluate the accuracy of Fast Read 102® compared to the Bürker chamber. Once the accuracy of the alternative method was demonstrated, we checked the precision and linearity test only using Fast Read 102®. The data were statistically analyzed by average, standard deviation and coefficient of variation percentages inter and intra operator. Results All the tests performed met the established acceptance criteria of a coefficient of variation of less than ten percent. For the cell count, the precision reached by each operator had a coefficient of variation of less than ten percent (total cells) and under five percent (viable cells). The best range of dilution, to obtain a slope line value very similar to 1, was between 1:8 and 1:128. Conclusions Our data demonstrated that the Fast Read 102® count method is accurate, precise and ensures the linearity of the results obtained in a range of cell dilution. Under our standard method procedures, this assay may thus be considered a good quality control method for the cell count as a batch release quality control test. Moreover, the Fast Read 102® chamber is a plastic, disposable device that allows a number of samples to be counted in the same chamber. Last but not least, it overcomes the problem of chamber washing after use and so allows a cell count in a clean environment such as that in a Cell Factory. In a good manufacturing practice setting the disposable cell counting devices will allow a single use of the count chamber they can then be thrown away, thus avoiding the waste disposal of vital dye (e.g. Trypan Blue) or lysing solution (e.g. Tuerk solution). PMID:22650233

In situ testing of a satellite or other object prior to development

NASA Technical Reports Server (NTRS)

Eagen, James H. (Inventor); Vujcich, Michael (Inventor); Scharton, Terry D. (Inventor)

2002-01-01

A method and system for testing a test object, such as a satellite, is disclosed. High energy acoustic testing is performed on the object by assembling an acoustical system about the test object rather than transporting the test object to a specially configured acoustic chamber. The acoustic system of the present invention preferably provides and directs acoustic energy directly to the surfaces of the test object rather than providing the test object in a high energy acoustic environment where a substantial amount of the acoustic energy is randomly directed within a chamber having the test object. Additionally, the present invention further provides for mechanical vibration tests concurrently or serially with acoustic testing, wherein the object is not required to be transported.

Suitability of small environmental chambers to test the emission of biocides from treated materials into the air

NASA Astrophysics Data System (ADS)

Horn, Wolfgang; Jann, Oliver; Wilke, Olaf

Biocides are used to protect materials that might be damaged by fungal, microbial or insect activity. The aim of this study is to develop a method for the measurement of these organic compounds, which generally have low or moderate vapor pressures. The biocides considered in this study are permethrin, dichlofluanid, tolylfluanid, iodpropinylbutylcarbamat, octylisothiazolinone, tebuconazole and propiconazole. The emission from two commercial products (plastic foil, wool carpet) containing biocides and of seven types of biocidal formulations applied to wood or clay tiles were investigated in 20-l glass emission test chambers. Each chamber test was performed over a period of 100-200 days, and one investigation was conducted over several years. Compared to volatile organic compounds, low-volatility compounds show totally different emission curves in chamber tests; maximal emission values may be reached in days or weeks. A period of 3 months is sometimes necessary for the determination of area-specific emission rates (SER a's). The SER a's (μg m -2 h -1) from biocide-containing products were determined for permethrin (0.006), propiconazole (0.3), dichlofluanid (2.0), tolylfluanid (1.0), octylisothiazolinone (2.5) and iodpropinylbutylcarbamat (2). In most cases, the SER a stayed at its maximum value or declined slowly over the test period. Additionally, a chamber test begun in 1994 with a piece of wood treated with a typical mixture of biocides dissolved in a technical solvent was continued. SER a's (μg m -2 h -1) for dichlofluanid (0.20), tebuconazole (0.49) and permethrin (0.08) remained detectable after the period of nearly 9 years during which the sample remained continuously in the chamber. This test proved the very slow decrease of emission of low-volatility compounds like permethrin and tebuconazole.

Performance studies of resistive Micromegas chambers for the upgrade of the ATLAS Muon Spectrometer

NASA Astrophysics Data System (ADS)

Ntekas, Konstantinos

2018-02-01

The ATLAS collaboration at LHC has endorsed the resistive Micromegas technology (MM), along with the small-strip Thin Gap Chambers (sTGC), for the high luminosity upgrade of the first muon station in the high-rapidity region, the so called New Small Wheel (NSW) project. The NSW requires fully efficient MM chambers, up to a particle rate of ˜ 15 kHz/cm2, with spatial resolution better than 100 μm independent of the track incidence angle and the magnetic field (B ≤ 0.3 T). Along with the precise tracking the MM should be able to provide a trigger signal, complementary to the sTGC, thus a decent timing resolution is required. Several tests have been performed on small (10 × 10 cm2) MM chambers using medium (10 GeV/c) and high (150 GeV/c) momentum hadron beams at CERN. Results on the efficiency and position resolution measured during these tests are presented demonstrating the excellent characteristics of the MM that fulfil the NSW requirements. Exploiting the ability of the MM to work as a Time Projection Chamber a novel method, called the μTPC, has been developed for the case of inclined tracks, allowing for a precise segment reconstruction using a single detection plane. A detailed description of the method along with thorough studies towards refining the method's performance are shown. Finally, during 2014 the first MM quadruplet (MMSW) following the NSW design scheme, comprising four detection planes in a stereo readout configuration, has been realised at CERN. Test-beam results of this prototype are discussed and compared to theoretical expectations.

Numerical and experimental analysis of heat transfer in injector plate of hydrogen peroxide hybrid rocket motor

NASA Astrophysics Data System (ADS)

Cai, Guobiao; Li, Chengen; Tian, Hui

2016-11-01

This paper is aimed to analyze heat transfer in injector plate of hydrogen peroxide hybrid rocket motor by two-dimensional axisymmetric numerical simulations and full-scale firing tests. Long-time working, which is an advantage of hybrid rocket motor over conventional solid rocket motor, puts forward new challenges for thermal protection. Thermal environments of full-scale hybrid rocket motors designed for long-time firing tests are studied through steady-state coupled numerical simulations of flow field and heat transfer in chamber head. The motor adopts 98% hydrogen peroxide (98HP) oxidizer and hydroxyl-terminated poly-butadiene (HTPB) based fuel as the propellants. Simulation results reveal that flowing liquid 98HP in head oxidizer chamber could cool the injector plate of the motor. The cooling of 98HP is similar to the regenerative cooling in liquid rocket engines. However, the temperature of the 98HP in periphery portion of the head oxidizer chamber is higher than its boiling point. In order to prevent the liquid 98HP from unexpected decomposition, a thermal protection method for chamber head utilizing silica-phenolics annular insulating board is proposed. The simulation results show that the annular insulating board could effectively decrease the temperature of the 98HP in head oxidizer chamber. Besides, the thermal protection method for long-time working hydrogen peroxide hybrid rocket motor is verified through full-scale firing tests. The ablation of the insulating board in oxygen-rich environment is also analyzed.

Research on the measurement of the ultraviolet irradiance in the xenon lamp aging test chamber

NASA Astrophysics Data System (ADS)

Ji, Muyao; Li, Tiecheng; Lin, Fangsheng; Yin, Dejin; Cheng, Weihai; Huang, Biyong; Lai, Lei; Xia, Ming

2018-01-01

This paper briefly introduces the methods of calibrating the irradiance in the Xenon lamp aging test chamber. And the irradiance under ultraviolet region is mainly researched. Three different detectors whose response wave range are respectively UVA (320 400nm), UVB (275 330nm) and UVA+B (280 400nm) are used in the experiment. Through comparing the measuring results with different detectors under the same xenon lamp source, we discuss the difference between UVA, UVB and UVA+B on the basis of the spectrum of the xenon lamp and the response curve of the detectors. We also point out the possible error source, when use these detectors to calibrate the chamber.

The use of three-dimensional printing to produce in vitro slice chambers

PubMed Central

Hyde, James; MacNicol, Melanie; Odle, Angela; Garcia-Rill, Edgar

2014-01-01

Background In recent years, 3D printing technology has become inexpensive and simple enough that any lab can own and use one of these printers. New Method We explored the potential use of 3D printers for quickly and easily producing in vitro slice chambers for patch clamp electrophysiology. Slice chambers were produced using five available plastics: ABS, PLA, Nylon 618, Nylon 680, and T-glase. These “lab-made” chambers were also made using stereolithography through a professional printing service (Shapeways). This study measured intrinsic membrane properties of neurons in the brain stem pedunculopontine nucleus (PPN) and layer V pyramidal neurons in retrosplenial cortex. Results Nylon 680 and T-glase significantly hyperpolarized PPN neurons. ABS increased input resistance, decreased action potential amplitude, and increased firing frequency in pyramidal cortical neurons. To test long term exposure to each plastic, human neuroblastoma SHSY5Y cell cultures were exposed to each plastic for 1 week. ABS decreased cell counts while Nylon 618 and Shapeways plastics eliminated cells. Primary mouse pituitary cultures were also tested for 24-hour exposure. ABS decreased cell counts while Nylon 618 and Shapeways plastics decreased cell counts. Comparison to Existing Methods Chambers can be quickly and inexpensively printed in the lab. ABS, PLA, Nylon 680, and T-glase plastics would suffice for many experiments instead of commercially produced slice chambers. Conclusions While these technologies are still in their infancy, they represent a powerful addition to the lab environment. With careful selection of print material, slice chambers can be quickly and inexpensively manufactured in the lab. PMID:25251556

A comparison of total inward leakage measured using sodium chloride (NaCl) and corn oil aerosol methods for air-purifying respirators.

PubMed

Rengasamy, Samy; Zhuang, Ziqing; Niezgoda, George; Walbert, Gary; Lawrence, Robert; Boutin, Brenda; Hudnall, Judith; Monaghan, William P; Bergman, Michael; Miller, Colleen; Harris, James; Coffey, Christopher

2018-05-21

The International Organization for Standardization (ISO) standard 16900-1:2014 specifies the use of sodium chloride (NaCl) and corn oil aerosols, and sulfur hexafluoride gas for measuring total inward leakage (TIL). However, a comparison of TIL between different agents is lacking. The objective of this study was to measure and compare TIL for respirators using corn oil and NaCl aerosols. TIL was measured with 10 subjects donning two models of filtering facepiece respirators (FFRs) including FFP1, N95, P100, and elastomeric half-mask respirators (ERs) in NaCl and corn oil aerosol test chambers, using continuous sampling methods. After fit testing with a PortaCount (TSI, St. Paul, MN) using the Occupational Safety and Health Administration (OSHA) protocol, five subjects were tested in the NaCl chamber first and then in the corn oil chamber, while other subjects tested in the reverse order. TIL was measured as a ratio of mass-based aerosol concentrations in-mask to the test chamber, while the subjects performed ISO 16900-1-defined exercises. The concentration of NaCl aerosol was measured using two flame photometers, and corn oil aerosol was measured with one light scattering photometer. The same instruments were used to measure filter penetration in both chambers using a Plexiglas® setup. The size distribution of aerosols was determined using a scanning mobility particle sizer and charge was measured with an electrometer. Filter efficiency was measured using an 8130 Automated Filter Tester (TSI). Results showed the geometric mean TIL for corn oil aerosol for one model each of all respirator categories, except P100, were significantly (p<0.05) greater than for NaCl aerosol. Filter penetration in the two test chambers showed a trend similar to TIL. The count median diameter was ∼82 nm for NaCl and ∼200 nm for corn oil aerosols. The net positive charge for NaCl aerosol was relatively larger. Both fit factor and filter efficiency influence TIL measurement. Overall, TIL determination with aerosols of different size distributions and charges using different methodologies may produce dissimilar results.

Some effects of thermal-cycle-induced deformation in rocket thrust chambers

NASA Technical Reports Server (NTRS)

Hannum, N. P.; Price, R. G., Jr.

1981-01-01

The deformation process observed in the hot gas side wall of rocket combustion chambers was investigaged for three different liner materials. Five thrust chambers were cycled to failure by using hydrogen and oxygen as propellants at a chamber pressure of 4.14 MN/cu m. The deformation was observed nondestructively at midlife points and destructively after failure occurred. The cyclic life results are presented with an accompanying discussion about the problems of life prediction associated with the types of failures encountered in the present work. Data indicating the deformation of the thrust chamber liner as cycles are accumulated are presented for each of the test thrust chambers. From these deformation data and observation of the failure sites it is evident that modeling the failure process as classic low cycle thermal fatigue is inadequate as a life prediction method.

Design and fabrication of the vacuum systems for TPS pulsed septum magnets

NASA Astrophysics Data System (ADS)

Chan, C. K.; Chang, C. C.; Chen, C. L.; Yang, C. S.; Chen, C. S.; Lin, F. Y.; Chen, J. R.

2014-11-01

Three in-air pulsed septum magnets were developed to inject and extract electron beams for the 3 GeV synchrotron facility, the Taiwan Photon Source (TPS). The vacuum chamber is a novel combined aluminium-stainless steel design, using a bimetallic flange to connect the two material types. To evaluate the vacuum performances of these vacuum chambers, we set up a test bench at which we simultaneously measure the rates of thermal outgassing of the aluminium chamber and the septum tube with a throughput method. The test result indicates that the rate q72 of thermal outgassing measured after 1 day from baking at 150 °C was 1×10-13 mbar L s-1 cm-2. The magnetic leakage measurements show the combination of conductor slitting, magnetic shielding and the aluminium vacuum chamber reduce the peak value of the leakage field integral to ~10 G cm along the trajectory of the stored beam.

Hermetic Seal Leak Detection Apparatus with Variable Size Test Chamber

NASA Technical Reports Server (NTRS)

Kelley, Anthony R. (Inventor)

2015-01-01

The present invention is a versatile hermetic seal leak detection apparatus for testing hermetically sealed containers and devices for leaks without the need to create a custom or specially manufactured testing chamber conforming to the dimensions of the specific object under test. The size of the testing chamber may be mechanically adjusted by the novel use of bellows to reduce and optimize the amount of gas space in a test chamber which surrounds the hermetically sealed object under test. The present invention allows the size of the test chamber to be selectively adjusted during testing to provide an optimum test chamber gas space. The present invention may be further adapted to isolate and test specific portions of the hermetically sealed object under test for leaks.

Deployment and testing of a second prototype expandable surgical chamber in microgravity

NASA Technical Reports Server (NTRS)

Markham, Sanford M.; Rock, John A.

1991-01-01

During microgravity exposure, two separate expandable surgical chambers were tested. Both chambers had been modified to fit the microgravity work station without extending over the sides of the table. Both chambers were attached to a portable laminar flow generator which served two purposes: to keep the chambers expanded during use; and to provide an operative area environment free of contamination. During the tests, the chambers were placed on various parts of a total body moulage to simulate management of several types of trauma. The tests consisted of cleansing contusions, debridement of burns, and suturing of lacerations. Also, indigo carmine dye was deliberately injected into the chamber during the tests to determine the ease of cleansing the chamber walls after contamination by escaping fluids. Upon completion of the tests, the expandable surgical chambers were deflated, folded, and placed in a flattened state back into their original containers for storage and later disposal. Results are briefly discussed.

Dispersion and Input Control Capability in European Large Size Reverberant Acoustic Chambers

NASA Astrophysics Data System (ADS)

Yarza, A.; Lopez, J.; Ozores, E.

2012-07-01

The acoustic test in reverberant chamber is one of the load cases to be proved during the environmental test campaign that demonstrates the capability of a space- unit to survive the launch phase. The crucial requirement for the large size structures is often the survival of the acoustic vibration test, and can be defined as the design driver load case in many circumstances. In addition, the commercial market demands lighter structures as an objective to reduce costs. For an efficient optimisation of the product it is very important to have powerful structural analysis tools in order to obtain knowledge of the structural needs and to refine existing methods for the prediction of structural loads experienced during acoustic testing. In the same line, as part of the contributors involved in the test it is important to acquire knowledge of the characteristics of the reverberant chamber itself and the behaviour of the fluid. With this purpose, EADS CASA Espacio (ECE) has used the measured data of the parameters of the fluid extracted from test of the deployable reflectors validated in the past five years, with the final objective to improve and optimise the capability to face up the acoustic test. In this paper experimental data extracted from acoustic tests performed to space-units are presented. Information related to two European large size acoustic chambers are used. The pressure field inside the acoustic chamber has been post-processed with the objective to study the behaviour of the fluid during the test. The diffuseness of the pressure field and the control capability of the acoustic profile are parameters to be considered as contributors for the design of the structures. The homogeneity of the microphones’ measurements is taken into account to describe the dispersion of the pressure inside the reverberant chamber along the frequency domain. Upon of that, the capability of the facilities to control the input profile is analysed from a statistical point of view. The final conclusions allow defining the minimum tolerances to be considered based on the limits imposed by the chamber.

Orientation of colonized sand flies Phlebotomus papatasi, P. duboscqi, and Lutzomyia longipalpis (Diptera: Psychodidae) to diverse honeys using a 3-chamber in-line olfactometer.

PubMed

Wasserberg, G; Kirsch, P; Rowton, E D

2014-06-01

A 3-chamber in-line olfactometer designed for use with sand flies is described and tested as a high-throughput method to screen honeys for attractiveness to Phlebotomus papatasi (four geographic isolates), P. duboscqi (two geographic isolates), and Lutzomyia longipalpis maintained in colonies at the Walter Reed Army Institute of Research. A diversity of unifloral honey odors were evaluated as a proxy for the natural floral odors that sand flies may use in orientation to floral sugar sources in the field. In the 3-chamber in-line olfactometer, the choice modules come directly off both sides of the release area instead of angling away as in the Y-tube olfactometer. Of the 25 honeys tested, five had a significant attraction for one or more of the sand fly isolates tested. This olfactometer and high-throughput method has utility for evaluating a diversity of natural materials with unknown complex odor blends that can then be down-selected for further evaluation in wind tunnels and/or field scenarios. © 2014 The Society for Vector Ecology.

Test results for the evaluation of a glucometer for use under hyperbaric conditions: Technical report.

PubMed

Tsouras, Theo

2017-01-01

This study aimed to evaluate a recently developed equipment test method by assessing the safe and accurate functioning of the Abbott Optium FreeStyle H portable blood glucose monitor for use in the Alfred Hospital's hyperbaric chamber. The results of this study indicate that the test method can be used successfully to evaluate instruments and/or devices for use in the hyperbaric environment. The evaluation initially found that this particular glucose monitor contained a lithium battery which can be hazardous when used in the hyperbaric environment. However, upon further inspection it was determined the battery posed minimal risk for fire and explosion due to its small capacity and design application. The results indicate that the Abbott Optium FreeStyle H blood glucose monitor operated normally when used in the hyperbaric chamber. This glucometer was found to perform within the calibration specification requirements for accuracy at all stages of a typical hyperbaric treatment and as such the Abbott Optium FreeStyle H blood glucose monitor was deemed safe for use in the hyperbaric chamber at the Alfred Hospital. Copyright© Undersea and Hyperbaric Medical Society.

Liquid Methane/Oxygen Injector Study for Mars Ascent Engines

NASA Technical Reports Server (NTRS)

Trinh, Huu Phuoc

1999-01-01

As a part of the advancing technology of the cryogenic propulsion system for the Mars exploration mission, this effort aims at evaluating propellant injection concepts for liquid methane/liquid oxygen (LOX) rocket engines. Split-triplet and unlike impinging injectors were selected for this study. A total of four injector configurations were tested under combustion conditions in a modular combustor test article (MCTA), equipped with optically accessible windows, at MSFC. A series of forty hot-fire tests, which covered a wide range of engine operating conditions with the chamber pressure ranging from 320 to 510 and the mixture ratio from 1.5 to 3.5, were conducted. The test matrix also included a variation in the combustion chamber length for the purpose of investigating its effects on the combustion performance and stability. Initial assessments of the test results showed that the injectors provided stable combustion and there were no injector face overheating problems under all operating conditions. The Raman scattering signal measurement method was successfully demonstrated for the hydrocarbon/oxygen reactive flow field. The near-injector face flow field was visually observed through the use of an infrared camera. Chamber wall temperature, high frequency chamber pressure, and average throat section heat flux were also recorded throughout the test series. Assessments of the injector performance are underway.

Characterization of Low-Frequency Combustion Stability of the Fastrac Engine

NASA Technical Reports Server (NTRS)

Rocker, Marvin; Jones, Preston (Technical Monitor)

2002-01-01

A series of tests were conducted to measure the combustion performance of the Fastrac engine thrust chamber. During mainstage, the thrust chamber exhibited no large-amplitude chamber pressure oscillations that could be identified as low-frequency combustion instability or 'chug'. However, during start-up and shutdown, the thrust chamber very briefly exhibited large-amplitude chamber pressure oscillations that were identified as chug. These instabilities during start-up and shutdown were regarded as benign due to their brevity. Linear models of the thrust chamber and the propellant feed systems were formulated for both the thrust chamber component tests and the flight engine tests. These linear models determined the frequency and decay rate of chamber pressure oscillations given the design and operating conditions of the thrust chamber and feed system. The frequency of chamber pressure oscillations determined from the model closely matched the frequency of low-amplitude, low-frequency chamber pressure oscillations exhibited in some of the later thrust chamber mainstage tests. The decay rate of the chamber pressure oscillations determined from the models indicated that these low-frequency oscillations were stable. Likewise, the decay rate, determined from the model of the flight engine tests indicated that the low-frequency chamber pressure oscillations would be stable.

Filament wound rocket motor chambers

NASA Technical Reports Server (NTRS)

1976-01-01

The design, analysis, fabrication and testing of a Kevlar-49/HBRF-55A filament wound chamber is reported. The chamber was fabricated and successfully tested to 80% of the design burst pressure. Results of the data reduction and analysis from the hydrotest indicate that the chamber design and fabrication techniques used for the chamber were adequate and the chamber should perform adequately in a static test.

An Evaluation of the Additional Acoustic Power Needed to Overcome the Effects of a Test-Article's Absorption During Reverberant Chamber Acoustic Testing of Spaceflight Hardware

NASA Technical Reports Server (NTRS)

Hozman, Aron D.; Hughes, William O.

2014-01-01

The exposure of a customer's aerospace test-article to a simulated acoustic launch environment is typically performed in a reverberant acoustic test chamber. The acoustic pre-test runs that will ensure that the sound pressure levels of this environment can indeed be met by a test facility are normally performed without a test-article dynamic simulator of representative acoustic absorption and size. If an acoustic test facility's available acoustic power capability becomes maximized with the test-article installed during the actual test then the customer's environment requirement may become compromised. In order to understand the risk of not achieving the customer's in-tolerance spectrum requirement with the test-article installed, an acoustic power margin evaluation as a function of frequency may be performed by the test facility. The method for this evaluation of acoustic power will be discussed in this paper. This method was recently applied at the NASA Glenn Research Center Plum Brook Station's Reverberant Acoustic Test Facility for the SpaceX Falcon 9 Payload Fairing acoustic test program.

An Evaluation of the Additional Acoustic Power Needed to Overcome the Effects of a Test-Article's Absorption during Reverberant Chamber Acoustic Testing of Spaceflight Hardware

NASA Technical Reports Server (NTRS)

Hozman, Aron D.; Hughes, William O.

2014-01-01

The exposure of a customers aerospace test-article to a simulated acoustic launch environment is typically performed in a reverberant acoustic test chamber. The acoustic pre-test runs that will ensure that the sound pressure levels of this environment can indeed be met by a test facility are normally performed without a test-article dynamic simulator of representative acoustic absorption and size. If an acoustic test facilitys available acoustic power capability becomes maximized with the test-article installed during the actual test then the customers environment requirement may become compromised. In order to understand the risk of not achieving the customers in-tolerance spectrum requirement with the test-article installed, an acoustic power margin evaluation as a function of frequency may be performed by the test facility. The method for this evaluation of acoustic power will be discussed in this paper. This method was recently applied at the NASA Glenn Research Center Plum Brook Stations Reverberant Acoustic Test Facility for the SpaceX Falcon 9 Payload Fairing acoustic test program.

Automated assessment of pain in rats using a voluntarily accessed static weight-bearing test

PubMed Central

Kim, Hung Tae; Uchimoto, Kazuhiro; Duellman, Tyler; Yang, Jay

2015-01-01

The weight-bearing test is one method to assess pain in rodent animal models; however, the acceptance of this convenient method is limited by the low throughput data acquisition and necessity of confining the rodents to a small chamber. New methods We developed novel data acquisition hardware and software, data analysis software, and a conditioning protocol for an automated high throughput static weight-bearing assessment of pain. With this device, the rats voluntarily enter the weighing chamber, precluding the necessity to restrain the animals and thereby removing the potential stress-induced confounds as well as operator selection bias during data collection. We name this device the Voluntarily Accessed Static Incapacitance Chamber (VASIC). Results Control rats subjected to the VASIC device provided hundreds of weight-bearing data points in a single behavioral assay. Chronic constriction injury (CCI) surgery and paw pad injection of complete Freund's adjuvant (CFA) or carrageenan in rats generated hundreds of weight-bearing data during a 30 minute recording session. Rats subjected to CCI, CFA, or carrageenan demonstrated the expected bias in weight distribution favoring the un-operated leg, and the analgesic effect of i.p. morphine was demonstrated. In comparison with existing methods, brief water restriction encouraged the rats to enter the weighing chamber to access water, and an infrared detector confirmed the rat position with feet properly positioned on the footplates, triggering data collection. This allowed hands-off measurement of weight distribution data reducing operator selection bias. Conclusion The VASIC device should enhance the hands-free parallel collection of unbiased weight-bearing data in a high throughput manner, allowing further testing of this behavioral measure as an effective assessment of pain in rodents. PMID:26143745

Oxygen-hydrogen thrusters for Space Station auxiliary propulsion systems

NASA Technical Reports Server (NTRS)

Berkman, D. K.

1984-01-01

The feasibility and technology requirements of a low-thrust, high-performance, long-life, gaseous oxygen (GO2)/gaseous hydrogen (GH2) thruster were examined. Candidate engine concepts for auxiliary propulsion systems for space station applications were identified. The low-thrust engine (5 to 100 lb sub f) requires significant departure from current applications of oxygen/hydrogen propulsion technology. Selection of the thrust chamber material and cooling method needed or long life poses a major challenge. The use of a chamber material requiring a minimum amount of cooling or the incorporation of regenerative cooling were the only choices available with the potential of achieving very high performance. The design selection for the injector/igniter, the design and fabrication of a regeneratively cooled copper chamber, and the design of a high-temperature rhenium chamber were documented and the performance and heat transfer results obtained from the test program conducted at JPL using the above engine components presented. Approximately 115 engine firings were conducted in the JPL vacuum test facility, using 100:1 expansion ratio nozzles. Engine mixture ratio and fuel-film cooling percentages were parametrically investigated for each test configuration.

Influence of Structural Parameters on the Performance of Vortex Valve Variable-Thrust Solid Rocket Motor

NASA Astrophysics Data System (ADS)

Wei, Xianggeng; Li, Jiang; He, Guoqiang

2017-04-01

The vortex valve solid variable thrust motor is a new solid motor which can achieve Vehicle system trajectory optimization and motor energy management. Numerical calculation was performed to investigate the influence of vortex chamber diameter, vortex chamber shape, and vortex chamber height of the vortex valve solid variable thrust motor on modulation performance. The test results verified that the calculation results are consistent with laboratory results with a maximum error of 9.5%. The research drew the following major conclusions: the optimal modulation performance was achieved in a cylindrical vortex chamber, increasing the vortex chamber diameter improved the modulation performance of the vortex valve solid variable thrust motor, optimal modulation performance could be achieved when the height of the vortex chamber is half of the vortex chamber outlet diameter, and the hot gas control flow could result in an enhancement of modulation performance. The results can provide the basis for establishing the design method of the vortex valve solid variable thrust motor.

Performance of high area ratio nozzles for a small rocket thruster

NASA Technical Reports Server (NTRS)

Kushida, R. O.; Hermel, J.; Apfel, S.; Zydowicz, M.

1986-01-01

Theoretical estimates of supersonic nozzle performance have been compared to experimental test data for nozzles with an area ratio of 100:1 conical and 300:1 optimum contour, and 300:1 nozzles cut off at 200:1 and 100:1. These tests were done on a Hughes Aircraft Company 5 lbf monopropellant hydrazine thruster with chamber pressures ranging from 25 to 135 psia. The analytic method used is the conventional inviscid method of characteristic with correction for laminar boundary layer displacement and drag. Replacing the 100:1 conical nozzle with the 300:1 contoured nozzle resulted in an improvement in thrust performance of 0.74 percent at chamber pressure of 25 psia to 2.14 percent at chamber pressure of 135 psia. The data is significant because it is experimental verification that conventional nozzle design techniques are applicable even where the boundary layer is laminar and displaces as much as 35 percent of the flow at the nozzle exit plane.

Evaluation of Vortex Chamber Concepts for Liquid Rocket Engine Applications

NASA Technical Reports Server (NTRS)

Trinh, Huu Phuoc; Knuth, Williams; Michaels, Scott; Turner, James E. (Technical Monitor)

2000-01-01

Rocket-based combined-cycle engines (RBBC) being considered at NASA for future generation launch vehicles feature clusters of small rocket thrusters as part of the engine components. Depending on specific RBBC concepts, these thrusters may be operated at various operating conditions including power level and/or propellant mixture ratio variations. To pursue technology developments for future launch vehicles, NASA/Marshall Space Flight Center (MSFC) is examining vortex chamber concepts for the subject cycle engine application. Past studies indicated that the vortex chamber schemes potentially have a number of advantages over conventional chamber methods. Due to the nature of the vortex flow, relatively cooler propellant streams tend to flow along the chamber wall. Hence, the thruster chamber can be operated without the need of any cooling techniques. This vortex flow also creates strong turbulence, which promotes the propellant mixing process. Consequently, the subject chamber concepts not only offer the system simplicity but they also would enhance the combustion performance. The test results showed that the chamber performance was markedly high even at a low chamber length-to- diameter ratio (L/D). This incentive can be translated to a convenience in the thrust chamber packaging.

Simultaneous Identification and Antimicrobial Susceptibility Testing of Multiple Uropathogens on a Microfluidic Chip with Paper-Supported Cell Culture Arrays.

PubMed

Xu, Banglao; Du, Yan; Lin, Jinqiong; Qi, Mingyue; Shu, Bowen; Wen, Xiaoxia; Liang, Guangtie; Chen, Bin; Liu, Dayu

2016-12-06

A microfluidic chip was developed for one-step identification and antimicrobial susceptibility testing (AST) of multiple uropathogens. The polydimethylsiloxane (PDMS) microchip used had features of cell culture chamber arrays connected through a sample introduction channel. At the bottom of each chamber, a paper substrate preloaded with chromogenic media and antimicrobial agents was embedded. By integrating a hydrophobic membrane valve on the microchip, the urine sample can be equally distributed into and confined in individual chambers. The identification and AST assays on multiple uropathogens were performed by combining the spatial resolution of the cell culture arrays and the color resolution from the chromogenic reaction. The composite microbial testing assay was based on dynamic changes in color in a serial of chambers. The bacterial antimicrobial susceptibility was determined by the lowest concentration of an antimicrobial agent that is capable of inhibiting the chromogenic reaction. Using three common uropathogenic bacteria as test models, the developed microfluidic approach was demonstrated to be able to complete the multiple colorimetric assays in 15 h. The accuracy of the microchip method, in comparison with that of the conventional approach, showed a coincidence of 94.1%. Our data suggest this microfluidic approach will be a promising tool for simple and fast uropathogen testing in resource-limited settings.

21 CFR 874.1060 - Acoustic chamber for audiometric testing.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Acoustic chamber for audiometric testing. 874.1060... (CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Diagnostic Devices § 874.1060 Acoustic chamber for audiometric testing. (a) Identification. An acoustic chamber for audiometric testing is a room that is...

Young inflorescence-bearing shoots with roots of Tradescantia clone BNL 4430 cultivated in nutrient solution circulating systems: an alternative to potted plants and cuttings for mutagenicity tests.

PubMed

Shima, N; Xiao, L Z; Sakuramoto, F; Ichikawa, S

1997-12-12

The use of young inflorescence-bearing shoots with roots of Tradescantia clone BNL 4430 cultivated in a nutrient solution circulating (NSC) growth chamber was tested and developed as an alternative method for using Tradescantia plants in mutagenicity testings. The NSC growth chamber was designed for our requirements, based on trial cultivations of the shoots with roots in its smaller-sized prototype. The nutrient solution used was a 1/2500 Hyponex solution. The characteristics of this clone, i.e., many new shoots constantly emerging from the basal nodes one after another and its short height favorable for early flowering, made it possible to prepare many young inflorescence-bearing shoots with roots at one time. A simplified NSC cultivation system could also be developed at a lower cost, and by using it together with the NSC growth chamber, recycling of untreated materials was established for supplying steadily enough amounts of young inflorescence-bearing shoots with roots for mutagenicity testings. Compared with traditional methods of using potted plants or cuttings, the new method exhibited more stable flower production, better stamen-hair growth and a significantly lower spontaneous (background) mutation frequency, and could produce more inflorescences per space. The use of such young inflorescence-bearing shoots with roots was therefore judged to be satisfactory to serve as a new mutagenicity test system alternating with potted plants and cuttings.

CAPSTONE REPORT ON THE DEVELOPMENT OF A STANDARD TEST METHOD FOR VOC EMISSIONS FROM INTERIOR LATEX PAINT AND ALKYD PAINTS

EPA Science Inventory

The report gives details of a small-chamber test method developed by the EPA for characterizing volatile organic compound (VOC) emissions from interior latex and alkyd paints. Current knowledge about VOC, including hazardous air pollutant, emissions from interior paints generated...

An inter-laboratory comparison study of the ANSI/BIFMA standard test method M7.1 for furniture

EPA Science Inventory

Five laboratories using five different test chambers participated in the study to quantify within- and between-laboratory variability in the measurement of emissions of volatile organic compounds (VOCs) from new commercial furniture test items following ANSI/BIFMA M7.1. Test item...

CO2 flux determination by closed-chamber methods can be seriously biased by inappropriate application of linear regression

NASA Astrophysics Data System (ADS)

Kutzbach, L.; Schneider, J.; Sachs, T.; Giebels, M.; Nykänen, H.; Shurpali, N. J.; Martikainen, P. J.; Alm, J.; Wilmking, M.

2007-07-01

Closed (non-steady state) chambers are widely used for quantifying carbon dioxide (CO2) fluxes between soils or low-stature canopies and the atmosphere. It is well recognised that covering a soil or vegetation by a closed chamber inherently disturbs the natural CO2 fluxes by altering the concentration gradients between the soil, the vegetation and the overlying air. Thus, the driving factors of CO2 fluxes are not constant during the closed chamber experiment, and no linear increase or decrease of CO2 concentration over time within the chamber headspace can be expected. Nevertheless, linear regression has been applied for calculating CO2 fluxes in many recent, partly influential, studies. This approach was justified by keeping the closure time short and assuming the concentration change over time to be in the linear range. Here, we test if the application of linear regression is really appropriate for estimating CO2 fluxes using closed chambers over short closure times and if the application of nonlinear regression is necessary. We developed a nonlinear exponential regression model from diffusion and photosynthesis theory. This exponential model was tested with four different datasets of CO2 flux measurements (total number: 1764) conducted at three peatland sites in Finland and a tundra site in Siberia. The flux measurements were performed using transparent chambers on vegetated surfaces and opaque chambers on bare peat surfaces. Thorough analyses of residuals demonstrated that linear regression was frequently not appropriate for the determination of CO2 fluxes by closed-chamber methods, even if closure times were kept short. The developed exponential model was well suited for nonlinear regression of the concentration over time c(t) evolution in the chamber headspace and estimation of the initial CO2 fluxes at closure time for the majority of experiments. CO2 flux estimates by linear regression can be as low as 40% of the flux estimates of exponential regression for closure times of only two minutes and even lower for longer closure times. The degree of underestimation increased with increasing CO2 flux strength and is dependent on soil and vegetation conditions which can disturb not only the quantitative but also the qualitative evaluation of CO2 flux dynamics. The underestimation effect by linear regression was observed to be different for CO2 uptake and release situations which can lead to stronger bias in the daily, seasonal and annual CO2 balances than in the individual fluxes. To avoid serious bias of CO2 flux estimates based on closed chamber experiments, we suggest further tests using published datasets and recommend the use of nonlinear regression models for future closed chamber studies.

A dynamic soil chamber system coupled with a tunable diode laser for online measurements of delta-13C, delta-18O, and efflux rate of soil respired CO2

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

Powers, Heath H; Mcdowell, Nate; Hanson, David

2009-01-01

High frequency observations of the stable isotopic composition of CO(2) effluxes from soil have been sparse due in part to measurement challenges. We have developed an open-system method that utilizes a flow-through chamber coupled to a tunable diode laser (TDL) to quantify the rate of soil CO(2) efflux and its delta(13)C and delta(18)O values (delta(13)C(R) and delta(18)O(R), respectively). We tested the method first in the laboratory using an artificial soil test column and then in a semi-arid woodland. We found that the CO(2) efflux rates of 1.2 to 7.3 micromol m(-2) s(-1) measured by the chamber-TDL system were similar tomore » measurements made using the chamber and an infrared gas analyzer (IRGA) (R(2) = 0.99) and compared well with efflux rates generated from the soil test column (R(2) = 0.94). Measured delta(13)C and delta(18)O values of CO(2) efflux using the chamber-TDL system at 2 min intervals were not significantly different from source air values across all efflux rates after accounting for diffusive enrichment. Field measurements during drought demonstrated a strong dependency of CO(2) efflux and isotopic composition on soil water content. Addition of water to the soil beneath the chamber resulted in average changes of +6.9 micromol m(-2) s(-1), -5.0 per thousand, and -55.0 per thousand for soil CO(2) efflux, delta(13)C(R) and delta(18)O(R), respectively. All three variables initiated responses within 2 min of water addition, with peak responses observed within 10 min for isotopes and 20 min for efflux. The observed delta(18)O(R) was more enriched than predicted from temperature-dependent H(2)O-CO(2) equilibration theory, similar to other recent observations of delta(18)O(R) from dry soils (Wingate L, Seibt U, Maseyk K, Ogee J, Almeida P, Yakir D, Pereira JS, Mencuccini M. Global Change Biol. 2008; 14: 2178). The soil chamber coupled with the TDL was found to be an effective method for capturing soil CO(2) efflux and its stable isotope composition at high temporal frequency.« less

Uniform, stable supply of medium for in vitro cell culture using a robust chamber

NASA Astrophysics Data System (ADS)

Wei, Juan; Liu, Chong; Jiang, Yang; Liu, Tao; Chen, Li; Liu, Bo; Li, Jingmin

2018-06-01

A uniform, stable supply of medium is important for in vitro cell culture. In this paper, a microfluidic device is presented for culturing cells inside a robust chamber with continuous perfusion of medium. The device consists of a main channel, two bifurcated channels and a culture chamber. The culture chamber connects to the bifurcated channels via multiple paths, and distributes symmetrically on the main channel, to improve the efficiency of medium exchange. Furthermore, regular polygonal chambers with various numbers of edges have been designed, to study the effects of chamber shape on flow fields. The finite element method has been employed to predict the effects of multiple paths on the uniformity and stability of flow fields in the culture chamber. Particle tracking technology has been used to evaluate the flow fields in the chambers, and PC-12 cells have been cultured using the microfluidic device, to test its validity. The results of simulation and experiment indicate that the microfluidic design could provide a continuous interstitial-like flow microenvironment, with a relatively stable and uniform supply of medium.

TVOC and formaldehyde emission behaviors from flooring materials bonded with environmental-friendly MF/PVAc hybrid resins.

PubMed

Kim, Sumin; Kim, Jin-A; An, Jae-Yoon; Kim, Hyun-Joong; Kim, Shin Do; Park, Jin Chul

2007-10-01

Polyvinyl acetate (PVAc) was added as a replacement for melamine-formaldehyde (MF) resin in the formaldehyde-based resin system to reduce formaldehyde and volatile organic compound (VOC) emissions from the adhesives used between plywoods and fancy veneers. A variety of techniques, including 20-l chamber, field and laboratory emission cell (FLEC), VOC analyzer and standard formaldehyde emission test (desiccator method), were used to determine the formaldehyde and VOC emissions from engineered flooring bonded with five different MF resin and PVAc blends at MF/PVAc ratios of 100:0, 70:30, 50:50, 30:70 and 0:100. Although urea-formaldehyde (UF) resin had the highest formaldehyde emission, the emission as determined by desiccator method was reduced by exchanging with MF resin. Furthermore, the formaldehyde emission level was decreased with increasing addition of PVAc as the replacement for MF resin. UF resin in the case of beech was over 5.0 mg/l, which exceeded E2 (1.5-5.0 mg/l) grade. However, MF30:PVAc70 was

Acoustically Induced Vibration of Structures: Reverberant Vs. Direct Acoustic Testing

NASA Technical Reports Server (NTRS)

Kolaini, Ali R.; O'Connell, Michael R.; Tsoi, Wan B.

2009-01-01

Large reverberant chambers have been used for several decades in the aerospace industry to test larger structures such as solar arrays and reflectors to qualify and to detect faults in the design and fabrication of spacecraft and satellites. In the past decade some companies have begun using direct near field acoustic testing, employing speakers, for qualifying larger structures. A limited test data set obtained from recent acoustic tests of the same hardware exposed to both direct and reverberant acoustic field testing has indicated some differences in the resulting structural responses. In reverberant acoustic testing, higher vibration responses were observed at lower frequencies when compared with the direct acoustic testing. In the case of direct near field acoustic testing higher vibration responses appeared to occur at higher frequencies as well. In reverberant chamber testing and direct acoustic testing, standing acoustic modes of the reverberant chamber or the speakers and spacecraft parallel surfaces can strongly couple with the fundamental structural modes of the test hardware. In this paper data from recent acoustic testing of flight hardware, that yielded evidence of acoustic standing wave coupling with structural responses, are discussed in some detail. Convincing evidence of the acoustic standing wave/structural coupling phenomenon will be discussed, citing observations from acoustic testing of a simple aluminum plate. The implications of such acoustic coupling to testing of sensitive flight hardware will be discussed. The results discussed in this paper reveal issues with over or under testing of flight hardware that could pose unanticipated structural and flight qualification issues. Therefore, it is of paramount importance to understand the structural modal coupling with standing acoustic waves that has been observed in both methods of acoustic testing. This study will assist the community to choose an appropriate testing method and test setup in the planning stages.

Manufacture of Cryoshroud Surfaces for Space Simulation Chambers

NASA Technical Reports Server (NTRS)

Ash, Gary S.

2008-01-01

Environmental test chambers for space applications use internal shrouds to simulate temperature conditions encountered in space. Shroud temperatures may range from +150 C to -253 C (20 K), and internal surfaces are coated with special high emissivity/absorptivity paints. To obtain temperature uniformity over large areas, detailed thermal design is required for placement of tubing for gaseous or liquid nitrogen and helium and other exotic heat exchange fluids. The recent increase in space simulation activity related to the James Webb Space Telescope has led to the design of new cryogenic shrouds to meet critical needs in instrument package testing. This paper will review the design and manufacturing of shroud surfaces for several of these programs, including fabrication methods and the selection and application of paints for simulation chambers.

Localized treatments using commercial dust and liquid formulations of fipronil against Coptotermes formosanus (Isoptera: Rhinotermitidae) in the laboratory.

PubMed

Gautam, Bal K; Henderson, Gregg; Wang, Cai

2014-04-01

Use of proper application methods and formulations of termiticides are important to reduce their negative impact to the environment. In this study, we conducted laboratory experiments to determine the effect of localized treatments with commercial dust and liquid formulations of fipronil against Formosan subterranean termites, Coptotermes formosanus Shiraki. The test arena consisted of a specially designed 16-chambered structure with a center chamber connected to 5 foraging chambers that themselves were connected to 10 additional foraging chambers. One peripheral chamber received a liquid or dust treatment and termites were released in the center chamber. Results showed that >91% of the termites were dead within the 9-d test period despite the localized treatment of only 1 foraging chamber. Termites that were still alive after 9 d were transferred to an untreated dish and held for 10 more days. The majority of those termites were dead and the rest were moribund on day 19. Regardless of the specific dish treated, both formulations of fipronil were found to be highly efficacious. Termites did not exhibit repellency to either formulation. Our results suggest that localized (or spot) treatment with either commercially available dust or liquid formulations of fipronil can be a viable option for control of a termite infestation where complete soil drenching is not desirable. © 2013 Institute of Zoology, Chinese Academy of Sciences.

Modeling of atomization and distribution of drop-liquid fuel in unsteady swirling flows in a combustion chamber and free space

NASA Astrophysics Data System (ADS)

Sviridenkov, A. A.; Toktaliev, P. D.; Tretyakov, V. V.

2018-03-01

Numerical and experimental research of atomization and propagation of drop-liquid phase in swirling flow behind the frontal device of combustion chamber was performed. Numerical procedure was based on steady and unsteady Reynolds equations solution. It's shown that better agreement with experimental data could be obtained with unsteady approach. Fractional time step method was implemented to solve Reynolds equations. Models of primary and secondary breakup of liquid fuel jet in swirling flows are formulated and tested. Typical mean sizes of fuel droplets for base operational regime of swirling device and combustion chamber were calculated. Comparison of main features of internal swirling flow in combustion chamber with unbounded swirling flow was made.

The Test and Evaluation of a Non-Chromate Finishing Agent

NASA Technical Reports Server (NTRS)

Gulley, H.; Okhio, C. B.; Tacina, Robert (Technical Monitor)

2000-01-01

This research is focused on the design, development and implementation of an industry, military and commercial standard testing cell for surface coatings, which focuses on advanced non-chromate materials technology and their commercialization. Currently, within both private and commercial sectors, chromates are used in the corrosion prevention. processes. However, there is a great demand for chromate-free systems that are able to provide equal protection. At the end of this effort, it is intended that a patented alternative to chromate conversion coatings would be tested and processed for commercialization. Thus far, research studies have been concerned primarily with current corrosion knowledge and testing methods. Corrosion can be classified into five categories: The first type is uniform corrosion which is dominated by a uniform thinning due to an even and regular loss of metal. The second type is called localized corrosion in which most of the loss occurs in discrete areas. The third type, metallurgically influenced corrosion is a form of attack where metallurgy plays a significant role. The fourth type, titled mechanically assisted degradation is a form of attack where velocity, abrasion, and hydrodynamics control the corrosion process. The last type of corrosion is defined as environmentally induced cracking which occurs when cracks are produced under specific, premeditated stress. Oddly enough, with these varying classifications, there are not as many standardized corrosion testing sites. Two of the most common testing methods for corrosion are salt spray testing and filiform. Although neither has proven to be absolute, in terms of the resulting observations, our research aims to help provide data that may be used to support the standardization for corrosion testing. We would acquire and use a Singleton Cyclic Corrosion Testing Chamber. Singleton test chambers perform a wide range of commonly used catalytic corrosion tests. They are used throughout the industry, some of which are - automotive, aerospace, electronic and many more. In addition to this, Singleton test chambers are fully expandable to accommodate cyclic corrosion testing needs. Singleton chambers are also designed for complete compliance and conformity with ASTM (American Society for Testing and Materials), military and commercial standards.

SU-F-T-472: Validation of Absolute Dose Measurements for MR-IGRT With and Without Magnetic Field

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

Green, O; Li, H; Goddu, S

Purpose: To validate absolute dose measurements for a MR-IGRT system without presence of the magnetic field. Methods: The standard method (AAPM’s TG-51) of absolute dose measurement with ionization chambers was tested with and without the presence of the magnetic field for a clinical 0.32-T Co-60 MR-IGRT system. Two ionization chambers were used - the Standard Imaging (Madison, WI) A18 (0.123 cc) and the PTW (Freiburg, Germany). A previously reported Monte Carlo simulation suggested a difference on the order of 0.5% for dose measured with and without the presence of the magnetic field, but testing this was not possible until anmore » engineering solution to allow the radiation system to be used without the nominal magnetic field was found. A previously identified effect of orientation in the magnetic field was also tested by placing the chamber either parallel or perpendicular to the field and irradiating from two opposing angles (90 and 270). Finally, the Imaging and Radiation Oncology Core provided OSLD detectors for five irradiations each with and without the field - with two heads at both 0 and 90 degrees, and one head at 90 degrees only as it doesn’t reach 0 (IEC convention). Results: For the TG-51 comparison, expected dose was obtained by decaying values measured at the time of source installation. The average measured difference was 0.4%±0.12% for A18 and 0.06%±0.15% for Farmer chamber. There was minimal (0.3%) orientation dependence without the magnetic field for the A18 chamber, while previous measurements with the magnetic field had a deviation of 3.2% with chamber perpendicular to magnetic field. Results reported by IROC for the OSLDs with and without the field had a maximum difference of 2%. Conclusion: Accurate absolute dosimetry was verified by measurement under the same conditions with and without the magnetic field for both ionization chambers and independently-verifiable OSLDs.« less

Nevada STORMS project: Measurement of mercury emissions from naturally enriched surfaces

USGS Publications Warehouse

Gustin, M.S.; Lindberg, S.; Marsik, F.; Casimir, A.; Ebinghaus, R.; Edwards, G.; Hubble-Fitzgerald, C.; Kemp, R.; Kock, H.; Leonard, T.; London, J.; Majewski, M.; Montecinos, C.; Owens, J.; Pilote, M.; Poissant, L.; Rasmussen, P.; Schaedlich, F.; Schneeberger, D.; Schroeder, W.; Sommar, J.; Turner, R.; Vette, A.; Wallschlaeger, D.; Xiao, Z.; Zhang, H.

1999-01-01

Diffuse anthropogenic and naturally mercury-enriched areas represent long-lived sources of elemental mercury to the atmosphere. The Nevada Study and Tests of the Release of Mercury From Soils (STORMS) project focused on the measurement of mercury emissions from a naturally enriched area. During the project, concurrent measurements of mercury fluxes from naturally mercury-enriched substrate were made September 1-4, 1997, using four micrometeorological methods and seven field flux chambers. Ambient air mercury concentrations ranged from 2 to nearly 200 ng m-3 indicating that the field site is a source of atmospheric mercury. The mean daytime mercury fluxes, during conditions of no precipitation, measured with field chambers were 50 to 360 ng m-2 h-1, and with the micrometeorological methods were 230 to 600 ng m-2 h-1. This wide range in mercury emission rates reflects differences in method experimental designs and local source strengths. Mercury fluxes measured by many field chambers were significantly different (p < 0.05) but linearly correlated. This indicates that field chambers responded similarly to environmental conditions, but differences in experimental design and site heterogeneity had a significant influence on the magnitude of mercury fluxes. Data developed during the field study demonstrated that field flux chambers are ideal for assessment of the physicochemical processes driving mercury flux and development of an understanding of the magnitude of the influence of individual factors on flux. In general, mean mercury fluxes measured with micrometeorological methods during daytime periods were nearly 3 times higher than mean fluxes measured with field flux chambers. Micrometeorological methods allow for derivation of a representative mercury flux occurring from an unconstrained system and provide an assessment of the actual magnitude and variability of fluxes occurring from an area. Copyright 1999 by the American Geophysical Union.

Three-Dimensional Echocardiographic Assessment of Left Heart Chamber Size and Function with Fully Automated Quantification Software in Patients with Atrial Fibrillation.

PubMed

Otani, Kyoko; Nakazono, Akemi; Salgo, Ivan S; Lang, Roberto M; Takeuchi, Masaaki

2016-10-01

Echocardiographic determination of left heart chamber volumetric parameters by using manual tracings during multiple beats is tedious in atrial fibrillation (AF). The aim of this study was to determine the usefulness of fully automated left chamber quantification software with single-beat three-dimensional transthoracic echocardiographic data sets in patients with AF. Single-beat full-volume three-dimensional transthoracic echocardiographic data sets were prospectively acquired during consecutive multiple cardiac beats (≥10 beats) in 88 patients with AF. In protocol 1, left ventricular volumes, left ventricular ejection fraction, and maximal left atrial volume were validated using automated quantification against the manual tracing method in identical beats in 10 patients. In protocol 2, automated quantification-derived averaged values from multiple beats were compared with the corresponding values obtained from the indexed beat in all patients. Excellent correlations of left chamber parameters between automated quantification and the manual method were observed (r = 0.88-0.98) in protocol 1. The time required for the analysis with the automated quantification method (5 min) was significantly less compared with the manual method (27 min) (P < .0001). In protocol 2, there were excellent linear correlations between the averaged left chamber parameters and the corresponding values obtained from the indexed beat (r = 0.94-0.99), and test-retest variability of left chamber parameters was low (3.5%-4.8%). Three-dimensional transthoracic echocardiography with fully automated quantification software is a rapid and reliable way to measure averaged values of left heart chamber parameters during multiple consecutive beats. Thus, it is a potential new approach for left chamber quantification in patients with AF in daily routine practice. Copyright © 2016 American Society of Echocardiography. Published by Elsevier Inc. All rights reserved.

Experimental and theoretical investigation of fatigue life in reusable rocket thrust chambers

NASA Technical Reports Server (NTRS)

Hannum, N. P.; Kasper, H. J.; Pavli, A. J.

1976-01-01

During a test program to investigate low-cycle thermal fatigue, 13 rocket combustion chambers were fabricated and cyclically test fired to failure. Six oxygen-free, high-conductivity (OFHC) copper and seven Amzirc chambers were tested. The failures in the OFHC copper chambers were not typical fatigue failures but are described as creep rupture enhanced by ratcheting. The coolant channels bulged toward the chamber centerline, resulting in progressive thinning of the wall during each cycle. The failures in the Amzirc alloy chambers were caused by low-cycle thermal fatigue. The zirconium in this alloy was not evenly distributed in the chamber materials. The life that was achieved was nominally the same as would have been predicted from OFHC copper isothermal test data.

Dual-fission chamber and neutron beam characterization for fission product yield measurements using monoenergetic neutrons

NASA Astrophysics Data System (ADS)

Bhatia, C.; Fallin, B.; Gooden, M. E.; Howell, C. R.; Kelley, J. H.; Tornow, W.; Arnold, C. W.; Bond, E. M.; Bredeweg, T. A.; Fowler, M. M.; Moody, W. A.; Rundberg, R. S.; Rusev, G.; Vieira, D. J.; Wilhelmy, J. B.; Becker, J. A.; Macri, R.; Ryan, C.; Sheets, S. A.; Stoyer, M. A.; Tonchev, A. P.

2014-09-01

A program has been initiated to measure the energy dependence of selected high-yield fission products used in the analysis of nuclear test data. We present out initial work of neutron activation using a dual-fission chamber with quasi-monoenergetic neutrons and gamma-counting method. Quasi-monoenergetic neutrons of energies from 0.5 to 15 MeV using the TUNL 10 MV FM tandem to provide high-precision and self-consistent measurements of fission product yields (FPY). The final FPY results will be coupled with theoretical analysis to provide a more fundamental understanding of the fission process. To accomplish this goal, we have developed and tested a set of dual-fission ionization chambers to provide an accurate determination of the number of fissions occurring in a thick target located in the middle plane of the chamber assembly. Details of the fission chamber and its performance are presented along with neutron beam production and characterization. Also presented are studies on the background issues associated with room-return and off-energy neutron production. We show that the off-energy neutron contribution can be significant, but correctable, while room-return neutron background levels contribute less than <1% to the fission signal.

Cloud Physics Test in the Space Power Chamber

NASA Image and Video Library

1975-09-21

A researcher sets up equipment in the Space Power Chamber at National Aeronautics and Space Administration’s (NASA) Plum Brook Station to study the effects of contaminants on clouds. Drs. Rosa and Jorge Pena of Pennsylvania State University's Department of Meteorology initiated the program in an effort to develop methods of creating stable, long-lasting clouds in a test chamber in order to study their composition and formation. The researchers then wanted to use the artificially-created clouds to determine how they were affected by pollution. The 100-foot diameter and 122-foot high Space Power Chamber is the largest vacuum chamber in the world. The researchers covered the circular walls with muslin. A recirculating water system saturated the cloth. The facility engineers then reduced the chamber’s pressure which released the water from the muslin and generated a cloud. The researchers produced five different clouds in this first portion of this study. They discovered that they could not create stable clouds because of the heat generated by the water-pumping equipment. Nonetheless, they felt confident enough to commence planning the second phase of the program using a heat exchanger to cool the equipment.

Automated assessment of pain in rats using a voluntarily accessed static weight-bearing test.

PubMed

Kim, Hung Tae; Uchimoto, Kazuhiro; Duellman, Tyler; Yang, Jay

2015-11-01

The weight-bearing test is one method to assess pain in rodent animal models; however, the acceptance of this convenient method is limited by the low throughput data acquisition and necessity of confining the rodents to a small chamber. We developed novel data acquisition hardware and software, data analysis software, and a conditioning protocol for an automated high throughput static weight-bearing assessment of pain. With this device, the rats voluntarily enter the weighing chamber, precluding the necessity to restrain the animals and thereby removing the potential stress-induced confounds as well as operator selection bias during data collection. We name this device the Voluntarily Accessed Static Incapacitance Chamber (VASIC). Control rats subjected to the VASIC device provided hundreds of weight-bearing data points in a single behavioral assay. Chronic constriction injury (CCI) surgery and paw pad injection of complete Freund's adjuvant (CFA) or carrageenan in rats generated hundreds of weight-bearing data during a 30 minute recording session. Rats subjected to CCI, CFA, or carrageenan demonstrated the expected bias in weight distribution favoring the un-operated leg, and the analgesic effect of i.p. morphine was demonstrated. In comparison with existing methods, brief water restriction encouraged the rats to enter the weighing chamber to access water, and an infrared detector confirmed the rat position with feet properly positioned on the footplates, triggering data collection. This allowed hands-off measurement of weight distribution data reducing operator selection bias. The VASIC device should enhance the hands-free parallel collection of unbiased weight-bearing data in a high throughput manner, allowing further testing of this behavioral measure as an effective assessment of pain in rodents. Copyright © 2015. Published by Elsevier Inc.

Effect of headspace mixing in static chambers and sampling protocol on calculated CH4 fluxes from soils

NASA Astrophysics Data System (ADS)

Juszczak, R.; Pihlatie, M.; Christiansen, J. R.; Giebels, M.; Schreiber, P.; Aaltonen, H.; Korhonen, J.; Rasilo, T.; Chojnicki, B. H.; Urbaniak, M.

2009-04-01

Closed static chambers are often used for greenhouse gas flux measurements from soils. The type of chamber, chamber handling and sampling protocol can influence the measurements. In most cases the calculated fluxes are suspected to be underestimated mainly because of reduction of gas diffusion from the soil to chamber headspace due to changed trace gas concentration gradient. Thus, fans are often applied to obtain better mixing of the air inside the chamber headspace and in turn reduce the negative effect of decreased concentration gradient. The open question is, however, to which extent the fluxes are changed by fans and whether they still remain underestimated or may even be overestimated? On the other hand, different sampling protocols are used assuming that they do not affect the flux measurements. To test different types of static chambers and different sampling procedures applied for measurement of greenhouse gas (CH4 and N2O) fluxes a chamber calibration campaign was organized at Hyytiälä Forestry Field Station in Southern Finland during August-October 2008. The main aim of the campaign was to quantitatively assess the uncertaintities and errors related to static chamber measurements. During this campaign static chambers were tested for 5 different CH4 and N2O flux levels with 3 different soil conditions (moisture and porosity) in a calibration tank described by Pumpanen et al. (2004). Among the different experiments, several special tests were carried out with the closed static chambers. Here, results of two special tests are presented to document whether 1) the air mixing inside the chamber headspace, 2) different sampling procedures influence the CH4 fluxes, and 3) how different calculation methods lead to varying results. Two static chambers of different volumes (65.5 and 195 liters) but with the same circular shape and surface area were connected to a LOS GATOS fats methane analyzer. The CH4 concentration inside the chamber headspace was monitored continuously with 1Hz frequency. Additionally, two different manual samplings procedures were tested and gas samples from chamber headspace were taken for gas chromatograph (GC) and analysed in two different laboratories. Gas concentrations in the calibration tank were monitored with a GC and an automatic gas analyzer (INNOVA). The preliminary results showed that air mixing inside the chamber headspace, the way of chamber handling and sampling procedures could have pronounced influence on the trace gas concentration detection inside a chamber, and as a consequence the calculated chamber fluxes. The moment of chamber enclosure can lead to a rapid increase in CH4 concentration due to a pressure effect in the chambers without a vent tube. Thus, it is essential to critically estimate the time of the first sampling so that it is early enough after chamber enclosure, but not disturbed by the initial chamber handling. It was also observed that manual sampling of gas can change the CH4 concentration in the chamber headspace. When mixing the chamber headspace air by a syringe, the subsequent gas sampling in the syringe may affect the diffusion of gas between the soil and the chamber headspace, and hence affect the calculated fluxes. It was observed that mixing the chamber headspace with a fan instead of syringes, reduced this effect during the chamber enclosure. Overall, fluxes measured with chamber equipped with a fan always gave higher fluxes (up to 40%) as compared to fluxes measured from chambers without a fan. Results of our experiment lead to the assumption that these differences were generally larger the higher the chamber was, the less porous the soil was, and the higher the fluxes were. We conclude from our experiment that static chambers used for greenhouse gas flux measurements should be equipped with at least one fan and a vent tube to increase mixing and reduce pressure propagation in the chamber-soil system, and that special attention should be paid to the handling of the chamber and to the timing of the gas sampling. References: Pumpanen, J., Kolari, P., Ilvesniemi, H., Minkkinen, K., Vesala, T., Niinistö, S., Lohila, A., Larmola, T., Morero, M., Pihlatie, M., Janssens, I., Curiel Yuste, J., Grünzweig, J. M., Reth, S., Subke, J.-A., Savage, K., Kutsch, W., Østreng, G., Ziegler, W., Anthoni, P., Lindroth, A. & Hari, P. 2004. Comparison of different chamber techniques for measuring soil CO2 efflux. Agricultural and Forest Meteorology 123, 159-176.

Microgravity

NASA Image and Video Library

1997-07-01

Astronaut James D. Halsell, Jr., mission commander, uses a Hi-8mm camcorder to videotape the Hand Held Diffusion Test Cells (HHDTC), in the Spacelab Science Module aboard the Earth-orbiting Space Shuttle Columbia (STS-94). Each test cell has three chambers containing a protein solution, a buffer solution and a precipitant solution chamber. Using the liquid-liquid diffusion method, the different fluids are brought into contact but not mixed. Over a period of time, the fluids will diffuse into each other through the random motion of molecules. The gradual increase in concentration of the precipitant within the protein solution causes the proteins to crystallize.

Structure and mechanical properties of parts obtained by selective laser melting of metal powder based on intermetallic compounds Ni3Al

NASA Astrophysics Data System (ADS)

Smelov, V. G.; Sotov, A. V.; Agapovichev, A. V.; Nosova, E. A.

2018-03-01

The structure and mechanical properties of samples are obtained from metal powder based on intermetallic compound by selective laser melting. The chemical analysis of the raw material and static tensile test of specimens were made. Change in the samples’ structure and mechanical properties after homogenization during four and twenty-four hours were investigated. A small-sized combustion chamber of a gas turbine engine was performed by the selective laser melting method. The print combustion chamber was subjected to the gas-dynamic test in a certain temperature and time range.

Brayton Cycle Power System in the Space Power Facility

NASA Image and Video Library

1969-07-21

Set up of a Brayton Cycle Power System test in the Space Power Facility’s massive vacuum chamber at the National Aeronautics and Space Administration’s (NASA) Plum Brook Station in Sandusky, Ohio. The $28.4-million facility, which began operations in 1969, is the largest high vacuum chamber ever built. The chamber is 100 feet in diameter and 120 feet high. It can produce a vacuum deep enough to simulate the conditions at 300 miles altitude. The Space Power Facility was originally designed to test nuclear-power sources for spacecraft, but it was never used for that purpose. The Space Power Facility was first used to test a 15 to 20-kilowatt Brayton Cycle Power System for space applications. Three different methods of simulating solar heat were employed during the tests. Lewis researchers studied the Brayton power system extensively in the 1960s and 1970s. The Brayton engine converted solar thermal energy into electrical power. The system operated on a closed-loop Brayton thermodynamic cycle with a helium-xenon gas mixture as its working fluid. A space radiator was designed to serve as the system’s waste heat rejecter. The radiator was later installed in the vacuum chamber and tested in a simulated space environment to determine its effect on the power conversion system. The Brayton system was subjected to simulated orbits with 62 minutes of sun and 34 minutes of shade.

An investigation of the direct-drive method of susceptibility testing

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

Bonn, R.H.

1992-07-01

The Naval Surface Weapons Laboratory has constructed a small electrical subsystem for the purpose of evaluating electrical upset from various electromagnetic sources. The subsystem consists of three boxes, two of which are intended to be illuminated by electromagnetic waves. The two illuminated boxes are connected by two unshielded cable bundles. The goal of the Navy test series is to expose the subsystem to electromagnetic illumination from several different types of excitation, document upset levels, and compare the results. Before its arrival at Sandia National Laboratories (SNL) the system was illuminated in a mode stirred chamber and in an anechoic chamber.more » This effort was a continuation of that test program. The Sandia tests involved the test methodology referred to as bulk current injection (BCI). Because this is a poorly-shielded, multiple-aperture system, the method was not expected to compare closely to the other test methods. The test results show that. The BCI test methodology is a useful test technique for a subset of limited aperture systems; the methodology will produce incorrect answers when used improperly on complex systems; the methodology can produce accurate answers on simple systems with a well-controlled electromagnetic topology. This is a preliminary study and the results should be interpreted carefully.« less

Affect of Air Leakage into a Thermal-Vacuum Chamber on Helium Refrigeration Heat Load

NASA Technical Reports Server (NTRS)

Garcia, Sam; Meagher, Daniel; Linza, Robert; Saheli, Fariborz; Vargas, Gerardo; Lauterbach, John; Reis, Carl; Ganni, Venkatarao (Rao); Homan, Jonathan

2008-01-01

NASA s Johnson Space Center (JSC) Building 32 houses two large thermal-vacuum chambers (Chamber A and Chamber B). Within these chambers are liquid nitrogen shrouds to provide a thermal environment and helium panels which operate at 20K to provide cryopumping. Some amount of air leakage into the chambers during tests is inevitable. This causes "air fouling" of the helium panel surfaces due to the components of the air that adhere to the panels. The air fouling causes the emittance of the helium panels to increase during tests. The increase in helium panel emittance increases the heat load on the helium refrigerator that supplies the 20K helium for those panels. Planning for thermal-vacuum tests should account for this increase to make sure that the helium refrigerator capacity will not be exceeded over the duration of a test. During a recent test conducted in Chamber B a known-size air leak was introduced to the chamber. Emittance change of the helium panels and the affect on the helium refrigerator was characterized. A description of the test and the results will be presented.

An experimental and theoretical study of the flow phenomena within a vortex sink rate sensor

NASA Technical Reports Server (NTRS)

Goglia, G. L.; Patel, D. K.

1974-01-01

Tests were conducted to obtain a description of the flow field within a vortex sink rate sensor and to observe the influence of viscous effects on its performance. The characteristics of the sensor are described. The method for conducting the test is reported. It was determined that for a specific mass flow rate and the geometry of the vortex chamber, the flow in the vortex chamber was only affected, locally, by the size of the sink tube diameter. Within the sink tube, all three velocity components were found to be higher for the small sink tube diameters. As the speed of rotation of the sensor was increased, the tangential velocities within the vortex chamber, as well as in the sink tube, increased in proportion to the speed of rotation.

76 FR 17561 - Inflatable Personal Flotation Devices

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-30

... the grab breaking strength, tear strength, seam strength, and permeability tests for inflation chamber... Coated Fabrics), and ASTM D 1434-82 (Standard Test Method for Determining Gas Permeability... Government and Indian tribes, or on the distribution of power and responsibilities between the Federal...

Experimental and theoretical investigation of fatigue life in reusable rocket thrust chambers

NASA Technical Reports Server (NTRS)

Hannum, N. P.; Kasper, H. J.; Pavli, A. J.

1976-01-01

During a test program to investigate low-cycle thermal fatigue, 13 rocket combustion chambers were fabricated and cyclically test fired to failure. Six oxygen-free, high-conductivity (OFHC) copper and seven Amzirc chambers were tested. The chamber liners were fabricated of copper or copper alloy and contained milled coolant channels. The chambers were completed by means of an electroformed nickel closeout. The oxidant/fuel ratio for the liquid oxygen and gaseous hydrogen propellants was 6.0. The failures in the OFHC copper chambers were not typical fatigue failures but are described as creep rupture enhanced by ratcheting. The coolant channels bulged toward the chamber centerline, resulting in progressive thinning of the wall during each cycle. The failures in the Amzirc alloy chambers were caused by low-cycle thermal fatigue. The lives were much shorter than were predicted by an analytical structural analysis computer program used in conjunction with fatigue life data from isothermal test specimens, due to the uneven distribution of Zr in the chamber material.

Orbital transfer vehicle 3000 LBF thrust chamber assembly hot fire test program

NASA Technical Reports Server (NTRS)

Schneider, Judy; Hayden, Warren R.

1988-01-01

The Aerojet Orbital Transfer Vehicle (OTV) Thrust Chamber Assembly (TCA) concept consists of a hydrogen cooled chamber, and annular injector, and an oxygen cooled centerbody. The hot fire testing of a heat sink version of the chamber with only the throat section using hydrogen cooling is documented. Hydraulic performance of the injector and cooled throat were verified by water flow testing prior to TCA assembly. The cooled throat was proof tested to 3000 psia to verify the integrity of the codeposited EF nickel-cobalt closeout. The first set of hot fire tests were conducted with a heat sink throat to obtain heat flux information. After demonstration of acceptable heat fluxes, the heat sink throat was replaced with the LH2 cooled throat section. Fourteen tests were conducted with a heat sink chamber and throat at chamber pressures of 85 to 359 psia. The injector face was modified at this time to add more face coolant flow. Ten tests were then conducted at chamber pressures of 197 to 620 psia. Actual heat fluxes at the higher chamber pressure range were 23 percent higher than the average of 10 Btu/in 2 predicted.

SPF Full-scale emissions test method development status ...

EPA Pesticide Factsheets

This is a non-technical presentation that is intended to inform ASTM task group members about our intended approach to full-scale emissions testing that includes the application of spray foam in an environmental chamber. The presentation describes the approach to emissions characterization, types of measurement systems employed, and expected outcomes from the planned tests. Purpose of this presentation is to update the ASTM D22.05 work group regarding status of our full-scale emissions test method development.

Initial Back-to-Back Fission Chamber Testing in ATRC

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

Benjamin Chase; Troy Unruh; Joy Rempe

2014-06-01

Development and testing of in-pile, real-time neutron sensors for use in Materials Test Reactor experiments is an ongoing project at Idaho National Laboratory. The Advanced Test Reactor National Scientific User Facility has sponsored a series of projects to evaluate neutron detector options in the Advanced Test Reactor Critical Facility (ATRC). Special hardware was designed and fabricated to enable testing of the detectors in the ATRC. Initial testing of Self-Powered Neutron Detectors and miniature fission chambers produced promising results. Follow-on testing required more experiment hardware to be developed. The follow-on testing used a Back-to-Back fission chamber with the intent to providemore » calibration data, and a means of measuring spectral indices. As indicated within this document, this is the first time in decades that BTB fission chambers have been used in INL facilities. Results from these fission chamber measurements provide a baseline reference for future measurements with Back-to-Back fission chambers.« less

Nitrogen use efficiencies of spring barley grown under varying nitrogen conditions in the field and growth chamber

PubMed Central

Beatty, Perrin H.; Anbessa, Yadeta; Juskiw, Patricia; Carroll, Rebecka T.; Wang, Juan; Good, Allen G.

2010-01-01

Background and Aims Nitrogen-use efficiency (NUE) of cereals needs to be improved by nitrogen (N) management, traditional plant breeding methods and/or biotechnology, while maintaining or, optimally, increasing crop yields. The aims of this study were to compare spring-barley genotypes grown on different nitrogen levels in field and growth-chamber conditions to determine the effects on N uptake (NUpE) and N utilization efficiency (NUtE) and ultimately, NUE. Methods Morphological characteristics, seed yield and metabolite levels of 12 spring barley (Hordeum vulgare) genotypes were compared when grown at high and low nitrogen levels in field conditions during the 2007 and 2008 Canadian growing seasons, and in potted and hydroponic growth-chamber conditions. Genotypic NUpE, NUtE and NUE were calculated and compared between field and growth-chamber environments. Key Results Growth chamber and field tests generally showed consistent NUE characteristics. In the field, Vivar, Excel and Ponoka, showed high NUE phenotypes across years and N levels. Vivar also had high NUE in growth-chamber trials, showing NUE across complex to simplistic growth environments. With the high NUE genotypes grown at low N in the field, NUtE predominates over NUpE. N metabolism-associated amino acid levels were different between roots (elevated glutamine) and shoots (elevated glutamate and alanine) of hydroponically grown genotypes. In field trials, metabolite levels were different between Kasota grown at high N (elevated glutamine) and Kasota at low N plus Vivar at either N condition. Conclusions Determining which trait(s) or gene(s) to target to improve barley NUE is important and can be facilitated using simplified growth approaches to help determine the NUE phenotype of various genotypes. The genotypes studied showed similar growth and NUE characteristics across field and growth-chamber tests demonstrating that simplified, low-variable growth environments can help pinpoint genetic targets for improving spring barley NUE. PMID:20308048

Particle dispersing system and method for testing semiconductor manufacturing equipment

DOEpatents

Chandrachood, Madhavi; Ghanayem, Steve G.; Cantwell, Nancy; Rader, Daniel J.; Geller, Anthony S.

1998-01-01

The system and method prepare a gas stream comprising particles at a known concentration using a particle disperser for moving particles from a reservoir of particles into a stream of flowing carrier gas. The electrostatic charges on the particles entrained in the carrier gas are then neutralized or otherwise altered, and the resulting particle-laden gas stream is then diluted to provide an acceptable particle concentration. The diluted gas stream is then split into a calibration stream and the desired output stream. The particles in the calibration stream are detected to provide an indication of the actual size distribution and concentration of particles in the output stream that is supplied to a process chamber being analyzed. Particles flowing out of the process chamber within a vacuum pumping system are detected, and the output particle size distribution and concentration are compared with the particle size distribution and concentration of the calibration stream in order to determine the particle transport characteristics of a process chamber, or to determine the number of particles lodged in the process chamber as a function of manufacturing process parameters such as pressure, flowrate, temperature, process chamber geometry, particle size, particle charge, and gas composition.

Test method for assessing resistance of pine lumber and waferboard to mold

Treesearch

Carol A. Clausen; Michael West

2005-01-01

Methods are needed to evaluate the ability of framing lumber and composite construction materials to withstand mold growth when they are exposed to rain between manufacture and installation. A laboratory-controlled rain chamber was developed to expose biocide-treated specimens of pine lumber and waferboard to bi-weekly wetting followed by re-inoculation with test fungi...

Leak rate measurements for satellite subsystems and residual gas analysis during space environment tests. [thermal vacuum and solar simulation tests

NASA Technical Reports Server (NTRS)

Nuss, H. E.

1975-01-01

The measuring and evaluation procedure for the determination of leak rates of satellite subsystems with a quadrupole mass spectrometer, and the results of the residual gas analysis are described. The method selected for leak rate determination was placing the system into a vacuum chamber and furnishing the chamber with a mass spectrometer and calibrated leaks. The residual gas of a thermal vacuum test facility, in which the thermal balance test radiation input was simulated by a heated canister, was analyzed with the mass spectrometer in the atomic mass unit range up to 300 amu. In addition to the measurements during the space environment tests, mass spectrometric studies were performed with samples of spacecraft materials. The studies were carried out during tests for the projects HELIOS, AEROS B and SYMPHONIE.

Failure analysis of energy storage spring in automobile composite brake chamber

NASA Astrophysics Data System (ADS)

Luo, Zai; Wei, Qing; Hu, Xiaofeng

2015-02-01

This paper set energy storage spring of parking brake cavity, part of automobile composite brake chamber, as the research object. And constructed the fault tree model of energy storage spring which caused parking brake failure based on the fault tree analysis method. Next, the parking brake failure model of energy storage spring was established by analyzing the working principle of composite brake chamber. Finally, the data of working load and the push rod stroke measured by comprehensive test-bed valve was used to validate the failure model above. The experimental result shows that the failure model can distinguish whether the energy storage spring is faulted.

Deformational injection rate measuring method

NASA Astrophysics Data System (ADS)

Marčič, Milan

2002-09-01

After completing the diesel engine endurance testing, we detected various traces of thermal load on the walls of combustion chambers located in the engine pistons. The engines were fitted with ω combustion chambers. The thermal load of different intensity levels occurred where the spray of fuel, fuel vapor, and air interacted with the combustion chamber wall. The uneven thermal load distribution of the combustion chamber wall results from varying injection rates in each injection nozzle hole. The most widely applied controlling methods so far for injection rate measurement, such as the Zeuch and Bosch concepts, allow measurement of only the total injection rate in multihole nozzles, without providing any indication whatsoever of the injection rate differences in individual injection nozzle holes. The new deformational measuring method described in the article allows the injection rate to be measured in each hole of the multihole nozzle. The results of the measurements using this method showed that the differences occurred in injection rates of individual injection nozzle holes. These differences may be the cause of various thermal loads on the combustion chamber walls. The criterion for injection rate is the deformation of the membrane due to an increase in the fuel quantity in the measuring space and due to the pressure waves resulting from the fuel being injected into the measuring space. The membrane deformation is measured using strain gauges, glued to the membrane and forming the Wheatstone's bridge. We devoted special attention to the temperature compensation of the Wheatstone's bridge and the membrane, heated up during the measurements.

Measurements of CO2 exchange with an automated chamber system throughout the year: challenges in measuring night-time respiration on porous peat soil

NASA Astrophysics Data System (ADS)

Koskinen, M.; Minkkinen, K.; Ojanen, P.; Kämäräinen, M.; Laurila, T.; Lohila, A.

2014-01-01

We built an automatic chamber system to measure greenhouse gas (GHG) exchange in forested peatland ecosystems. We aimed to build a system robust enough which would work throughout the year and could measure through a changing snowpack in addition to producing annual GHG fluxes by integrating the measurements without the need of using models. The system worked rather well throughout the year, but it was not service free. Gap filling of data was still necessary. We observed problems in carbon dioxide (CO2) respiration flux estimation during calm summer nights, when a CO2 concentration gradient from soil/moss system to atmosphere builds up. Chambers greatly overestimated the night-time respiration. This was due to the disturbance caused by the chamber to the soil-moss CO2 gradient and consequent initial pulse of CO2 to the chamber headspace. We tested different flux calculation and measurement methods to solve this problem. The estimated flux was strongly dependent on (1) the starting point of the fit after closing the chamber, (2) the length of the fit, (3) the type of the fit (linear and polynomial), (4) the speed of the fan mixing the air inside the chamber, and (5) atmospheric turbulence (friction velocity, u*). The best fitting method (the most robust, least random variation) for respiration measurements on our sites was linear fitting with the period of 120-240 s after chamber closure. Furthermore, the fan should be adjusted to spin at minimum speed to avoid the pulse-effect, but it should be kept on to ensure mixing. If night-time problems cannot be solved, emissions can be estimated using daytime data from opaque chambers.

Relative toxicity of products of pyrolysis and combustion of polymeric materials using various test conditions

NASA Technical Reports Server (NTRS)

Hilado, C. J.

1976-01-01

Relative toxicity data for a large number of natural and synthetic polymeric materials are presented which were obtained by 11 pyrolysis and three flaming-combustion test methods. The materials tested include flexible and rigid polyurethane foams, different kinds of fabrics and woods, and a variety of commodity polymers such as polyethylene. Animal exposure chambers of different volumes containing mice, rats, or rabbits were used in the tests, which were performed over the temperature range from ambient to 800 C with and without air flow or recirculation. The test results are found to be sensitive to such variables as exposure mode, temperature, air flow and dilution, material concentration, and animal species, but relative toxicity rankings appear to be similar for many methods and materials. It is concluded that times to incapacitance and to death provide a more suitable basis for relative toxicity rankings than percent mortality alone, that temperature is the most important variable in the tests reported, and that variables such as chamber volume and animal species may not significantly affect the rankings.

25th Space Simulation Conference. Environmental Testing: The Earth-Space Connection

NASA Technical Reports Server (NTRS)

Packard, Edward

2008-01-01

Topics covered include: Methods of Helium Injection and Removal for Heat Transfer Augmentation; The ESA Large Space Simulator Mechanical Ground Support Equipment for Spacecraft Testing; Temperature Stability and Control Requirements for Thermal Vacuum/Thermal Balance Testing of the Aquarius Radiometer; The Liquid Nitrogen System for Chamber A: A Change from Original Forced Flow Design to a Natural Flow (Thermo Siphon) System; Return to Mercury: A Comparison of Solar Simulation and Flight Data for the MESSENGER Spacecraft; Floating Pressure Conversion and Equipment Upgrades of Two 3.5kw, 20k, Helium Refrigerators; Affect of Air Leakage into a Thermal-Vacuum Chamber on Helium Refrigeration Heat Load; Special ISO Class 6 Cleanroom for the Lunar Reconnaissance Orbiter (LRO) Project; A State-of-the-Art Contamination Effects Research and Test Facility Martian Dust Simulator; Cleanroom Design Practices and Their Influence on Particle Counts; Extra Terrestrial Environmental Chamber Design; Contamination Sources Effects Analysis (CSEA) - A Tool to Balance Cost/Schedule While Managing Facility Availability; SES and Acoustics at GSFC; HST Super Lightweight Interchangeable Carrier (SLIC) Static Test; Virtual Shaker Testing: Simulation Technology Improves Vibration Test Performance; Estimating Shock Spectra: Extensions beyond GEVS; Structural Dynamic Analysis of a Spacecraft Multi-DOF Shaker Table; Direct Field Acoustic Testing; Manufacture of Cryoshroud Surfaces for Space Simulation Chambers; The New LOTIS Test Facility; Thermal Vacuum Control Systems Options for Test Facilities; Extremely High Vacuum Chamber for Low Outgassing Processing at NASA Goddard; Precision Cleaning - Path to Premier; The New Anechoic Shielded Chambers Designed for Space and Commercial Applications at LIT; Extraction of Thermal Performance Values from Samples in the Lunar Dust Adhesion Bell Jar; Thermal (Silicon Diode) Data Acquisition System; Aquarius's Instrument Science Data System (ISDS) Automated to Acquire, Process, Trend Data and Produce Radiometric System Assessment Reports; Exhaustive Thresholds and Resistance Checkpoints; Reconfigurable HIL Testing of Earth Satellites; FPGA Control System for the Automated Test of MicroShutters; Ongoing Capabilities and Developments of Re-Entry Plasma Ground Tests at EADS-ASTRIUM; Operationally Responsive Space Standard Bus Battery Thermal Balance Testing and Heat Dissipation Analysis; Galileo - The Serial-Production AIT Challenge; The Space Systems Environmental Test Facility Database (SSETFD), Website Development Status; Simulated Reentry Heating by Torching; Micro-Vibration Measurements on Thermally Loaded Multi-Layer Insulation Samples in Vacuum; High Temperature Life Testing of 80Ni-20Cr Wire in a Simulated Mars Atmosphere for the Sample Analysis at Mars (SAM) Instrument Suit Gas Processing System (GPS) Carbon Dioxide Scrubber; The Planning and Implementation of Test Facility Improvements; and Development of a Silicon Carbide Molecular Beam Nozzle for Simulation Planetary Flybys and Low-Earth Orbit.

Efficiency tests of samplers for microbiological aerosols, a review

NASA Technical Reports Server (NTRS)

Henningson, E.; Faengmark, I.

1984-01-01

To obtain comparable results from studies using a variety of samplers of microbiological aerosols with different collection performances for various particle sizes, methods reported in the literature were surveyed, evaluated, and tabulated for testing the efficiency of the samplers. It is concluded that these samplers were not thoroughly tested, using reliable methods. Tests were conducted in static air chambers and in various outdoor and work environments. Results are not reliable as it is difficult to achieve stable and reproducible conditions in these test systems. Testing in a wind tunnel is recommended.

MEASUREMENT OF VOCS DESORBED FROM BUILDING MATERIALS--A HIGH TEMPERATURE DYNAMIC CHAMBER METHOD

EPA Science Inventory

Mass balance is a commonly used approach for characterizing the source and sink behavior of building materials. Because the traditional sink test methods evaluate the adsorption and desorption of volatile organic compounds (VOC) at ambient temperatures, the desorption process is...

Microbial ranking of porous packaging materials (exposure chamber method), ASTM method: collaborative study.

PubMed

Placencia, A M; Peeler, J T

1999-01-01

A collaborative study involving 11 laboratories was conducted to measure the microbial barrier effectiveness of porous medical packaging. Two randomly cut samples from each of 6 commercially available porous materials and one positive and one negative control were tested by one operator in each of 11 laboratories. Microbial barrier effectiveness was measured in terms of logarithm reduction value (LRV), which reflects the log10 microbial penetration of the material being tested. The logarithm of the final concentration is subtracted from that of the initial concentration to obtain the LRV. Thus the higher the LRV, the better the barrier. Repeatability standard deviations ranged from 6.42 to 16.40; reproducibility standard deviations ranged from 15.50 to 22.70. Materials B(53), C(50), D(CT), and E(45MF) differ significantly from the positive control. The microbial ranking of porous packaging materials (exposure chamber method), ASTM method, has been adopted First Action by AOAC INTERNATIONAL.

Determination of the Emissivity of Materials

DTIC Science & Technology

1962-12-31

testing. The window is protected by a magnetically-ope-ated rolling disc shutter. Bakeout heaters are provided to outgas the chamber before testing...nitrogen cold trap over a period of two hours. During this period the chamber was baked out at 350 °F. The ion-gettering pump was then started and the...If the chamber had been contaminated by previous testing, it was baked out at 350 °F during pump-down. During testing, the chamber walls were cooled to

Advanced Manufacturing Technologies (AMT): Additive Manufactured Hot Fire Planning and Testing in GRC Cell 32 Project

NASA Technical Reports Server (NTRS)

Fikes, John C.

2014-01-01

The objective of this project is to hot fire test an additively manufactured thrust chamber assembly TCA (injector and thrust chamber). GRC will install the additively manufactured Inconel 625 injector, two additively manufactured (SLM) water cooled Cu-Cr thrust chamber barrels and one additively manufactured (SLM) water cooled Cu-Cr thrust chamber nozzle on the test stand in Cell 32 and perform hot fire testing of the integrated TCA.

Modernization of NASA's Johnson Space Center Chamber: A Payload Transport Rail System to Support Cryogenic Vacuum Optical Testing of the James Webb Space Telescope (JWST)

NASA Technical Reports Server (NTRS)

Garcia, Sam; Homan, Jonathan; Speed, John

2016-01-01

NASA is the mission lead for the James Webb Space Telescope (JWST), the next of the "Great Observatories", scheduled for launch in 2018. It is directly responsible for the integration and test (I&T) program that will culminate in an end-to-end cryo vacuum optical test of the flight telescope and instrument module in Chamber A at NASA Johnson Space Center. Historic Chamber A is the largest thermal vacuum chamber at Johnson Space Center and one of the largest space simulation chambers in the world. Chamber A has undergone a major modernization effort to support the deep cryogenic, vacuum and cleanliness requirements for testing the JWST. This paper describe the challenges of developing, integrating and modifying new payload rails capable of transporting payloads within the thermal vacuum chamber up to 65,000 pounds. Ambient and Cryogenic Operations required to configure for testing will be explained. Lastly review historical payload configurations stretching from the Apollo program era to current James Webb Space Telescope testing.

Method and apparatus to produce high specific impulse and moderate thrust from a fusion-powered rocket engine

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

Cohen, Samuel A.; Pajer, Gary A.; Paluszek, Michael A.

A system and method for producing and controlling high thrust and desirable specific impulse from a continuous fusion reaction is disclosed. The resultant relatively small rocket engine will have lower cost to develop, test, and operate that the prior art, allowing spacecraft missions throughout the planetary system and beyond. The rocket engine method and system includes a reactor chamber and a heating system for heating a stable plasma to produce fusion reactions in the stable plasma. Magnets produce a magnetic field that confines the stable plasma. A fuel injection system and a propellant injection system are included. The propellant injectionmore » system injects cold propellant into a gas box at one end of the reactor chamber, where the propellant is ionized into a plasma. The propellant and fusion products are directed out of the reactor chamber through a magnetic nozzle and are detached from the magnetic field lines producing thrust.« less

CO2 flux determination by closed-chamber methods can be seriously biased by inappropriate application of linear regression

NASA Astrophysics Data System (ADS)

Kutzbach, L.; Schneider, J.; Sachs, T.; Giebels, M.; Nykänen, H.; Shurpali, N. J.; Martikainen, P. J.; Alm, J.; Wilmking, M.

2007-11-01

Closed (non-steady state) chambers are widely used for quantifying carbon dioxide (CO2) fluxes between soils or low-stature canopies and the atmosphere. It is well recognised that covering a soil or vegetation by a closed chamber inherently disturbs the natural CO2 fluxes by altering the concentration gradients between the soil, the vegetation and the overlying air. Thus, the driving factors of CO2 fluxes are not constant during the closed chamber experiment, and no linear increase or decrease of CO2 concentration over time within the chamber headspace can be expected. Nevertheless, linear regression has been applied for calculating CO2 fluxes in many recent, partly influential, studies. This approach has been justified by keeping the closure time short and assuming the concentration change over time to be in the linear range. Here, we test if the application of linear regression is really appropriate for estimating CO2 fluxes using closed chambers over short closure times and if the application of nonlinear regression is necessary. We developed a nonlinear exponential regression model from diffusion and photosynthesis theory. This exponential model was tested with four different datasets of CO2 flux measurements (total number: 1764) conducted at three peatlands sites in Finland and a tundra site in Siberia. Thorough analyses of residuals demonstrated that linear regression was frequently not appropriate for the determination of CO2 fluxes by closed-chamber methods, even if closure times were kept short. The developed exponential model was well suited for nonlinear regression of the concentration over time c(t) evolution in the chamber headspace and estimation of the initial CO2 fluxes at closure time for the majority of experiments. However, a rather large percentage of the exponential regression functions showed curvatures not consistent with the theoretical model which is considered to be caused by violations of the underlying model assumptions. Especially the effects of turbulence and pressure disturbances by the chamber deployment are suspected to have caused unexplainable curvatures. CO2 flux estimates by linear regression can be as low as 40% of the flux estimates of exponential regression for closure times of only two minutes. The degree of underestimation increased with increasing CO2 flux strength and was dependent on soil and vegetation conditions which can disturb not only the quantitative but also the qualitative evaluation of CO2 flux dynamics. The underestimation effect by linear regression was observed to be different for CO2 uptake and release situations which can lead to stronger bias in the daily, seasonal and annual CO2 balances than in the individual fluxes. To avoid serious bias of CO2 flux estimates based on closed chamber experiments, we suggest further tests using published datasets and recommend the use of nonlinear regression models for future closed chamber studies.

HHDTC - Cmdr Halsell photographs hardware

NASA Image and Video Library

2016-08-12

STS083-313-012 (4-8 April 1997) --- Astronaut James D. Halsell, Jr., mission commander, uses a Hi-8mm camcorder to videotape the Hand Held Diffusion Test Cells (HHDTC), in the Spacelab Module aboard the Earth-orbiting Space Shuttle Columbia. Each test cell has three chambers containing a protein solution, a buffer solution and a precipitant solution chamber. Using the liquid-liquid diffusion method, the different fluids are brought into contact but not mixed. Over a period of time, the fluids will diffuse into each other through the random motion of molecules. The gradual increase in concentration of the precipitant within the protein solution causes the proteins to crystallize.

Laboratory simulation of cratering on small bodies

NASA Technical Reports Server (NTRS)

Schmidt, Robert M.

1991-01-01

A new technique using external pressure was developed to simulate the lithostatic pressure due to self-gravity of small bodies. A 13-in. diameter cylindrical test chamber with L/D of 1 was fabricated to accommodate firing explosive charges with gas overpressures of up to 6000 psi. The chamber was hydrotested to 9000 psi. The method allows much larger scale factors that can be obtained with existing centrifuges and has the correct spherical geometry of self gravity. A simulant for jointed rock to be used in this fixture was developed using weakly cemented basalt. Various strength/pressure scaling theories can now be examined and tested.

Differences in CASA output according to the chamber type when analyzing frozen-thawed bull sperm.

PubMed

Ibănescu, Iulian; Leiding, Claus; Ciornei, Ştefan Gregore; Roșca, Petru; Sfartz, Ioana; Drugociu, Dan

2016-03-01

As demonstrated by some authors, the type of analyzing chamber can greatly influence the results of computer-assisted sperm analysis (CASA). This study aimed to compare three of the disposable chamber types currently available on the market and to determine whether the CASA output may be significantly different among them. The semen from five Fleckvieh bulls was analyzed by CASA using three different disposable chambers: Leja (20μm), MofA (20μm) and Minitube (20μm), at three different time points: immediately after filling the chamber, at 6min, and also at 12min after filling. Sperm concentration was also determined using the Nucleocounter® NC-100™ device and the hemocytometer as standard methods. The results showed higher values in terms of total and progressive sperm motility for MofA compared to the other two chambers immediately after filling (p<0.05), but higher values for Leja and Minitube after 6 and 12min (p<0.05). All three disposable chambers offered lower values for sperm concentration compared to standard methods (Leja: 68.4±4.9×106/mL; MofA: 80.8±9.6×106/mL; Minitube: 67.3±5.4×106/mL; Nucleocounter: 86.5×106/mL; Hemocytometer: 84.0×106/mL). We conclude that for rapid analyses the MofA chambers provide superior results when compared to the other types that we tested. However, when the analysis requires a longer duration, the Minitube type, and especially the Leja type provide a greater degree of confidence. Further, for determining sperm concentration we think that examiners would be more accurate using the Nucleocounter or the hemocytometer and should make use of CASA only when the other methods are not available. Copyright © 2016 Elsevier B.V. All rights reserved.

A microfluidic device with multi-valves system to enable several simultaneous exposure tests on Caenorhabditis elegans

NASA Astrophysics Data System (ADS)

Jung, Jaehoon; Nakajima, Masahiro; Masaru, Takeuchi; Huang, Qiang; Fukuda, Toshio

2014-03-01

In this paper, we report on a microfluidic device with a multi-valve system to conduct several exposure tests on Caenorhabditis elegans (C. elegans) simultaneously. It has pneumatic valves and no-moving-parts (NMP) valves. An NMP valve is incorporated with a chamber and enables the unidirectional movement of C. elegans in the chamber; once worms are loaded into the chamber, they cannot exit, regardless of the flow direction. To demonstrate the ability of the NMP valve to handle worms, we made a microfluidic device with three chambers. Each chamber was used to expose worms to Cd and Cu solutions, and K-medium. A pair of electrodes was installed in the device and the capacitance in-between the electrode was measured. When a C. elegans passed through the electrodes, the capacitance was changed. The capacitance change was proportional to the body volume of the worm, thus the body volume change by the heavy metal exposure was measured in the device. Thirty worms were divided into three groups and exposed to each solution. We confirmed that the different solutions induced differences in the capacitance changes for each group. These results indicate that our device is a viable method for simultaneously analyzing the effect of multiple stimuli on C. elegans.

The stabilization of the rock mass of the wieliczka salt mine through the backfilling of the witos chamber with the use of injection methods / Stabilizacji górotworu kopalni soli "wieliczka" poprzez likwidację komór "witos" z zastosowaniem metod iniekcji

NASA Astrophysics Data System (ADS)

D'Obyrn, Kajetan

2012-10-01

The Wieliczka Salt Mine is the most famous and the most visited mining industry monument in the world and it requires modern methods to ensure rock mass stability and tourists' security. Both for conservation and tourism organization reasons, the group of Warszawa-Wisla-Budryk-Lebzeltern-Upper Witos Chambers (Photo. 1, 2. 3) located the Kazanów mid-level at a depth of 117 m underground is extremely important. Discontinuous deformation occurring in this Chamber complex was eliminated by comprehensive securing work with anchor housing, but their final securing and stability is conditioned by further backfilling and sealing the Witos Chambers situated directly beneath. In the 1940s and 1950s, the Witos Chamber was backfilled with slag from the mine boilerhouse. However, slags with 80% compressibility are not backfilling material which would ensure the stability of the rock mass. The chambers were exploited in the early nineteenth century in the Spizit salts of the central part of the layered deposit. The condition of the Upper Witos, Wisla, Warszawa, Budryk, and Lebzeltern Chambers is generally good. The western part if the Lebzeltern Chamber (Fig. 1), which was threatened with collapse, was backfilled with sand. In all the chambers of the Witos complex, local deformation of ceiling rock of varying intensity is observed as well as significant destruction of the side walls of pillars between chambers. No hydrogeological phenomena are observed in the chambers. It has been attempted to solve the problem of stability of the rock mass in this region of the mine by extracting the slag and backfilling with sand, erecting concrete supporting pillars, backfilling the voids with sand, anchoring the ceiling and the side walls, the use of the pillar housing. The methods have either not been applied or have been proved insufficient to properly protect the excavation situated above. In order to select the optimal securing method, a geomechanical analysis was conducted in order to determine the condition of the chambers with particular emphasis on the pillars between the chambers. The analysis demonstrated the need to backfilling the Witos Chambers in order to improve the strength parameters of the pillars and the cross-level ledge. The next step consisted of selecting the sealing mix and testing how the additional burden and improving the slag strength parameters shall affect the stability of the excavations of the Kazanów mid-level. In order to determine the optimal composition of the backfilling mixtures, formulas of sealing brine slurries have been developed. Laboratory tests were also conducted concerning the strain parameters specifications of slags extracted from the Witos Chamber. Taking into account the slurry tests, and in particular, the density, strength and strain parameters, the optimal composition of the sealing mix was selected. The analysis of the results of numerical recalculations demonstrate that even the use of highest-density mixtures, backfilling(sealing) of the Witos Chambers should not cause significant disturbance of the current tension in the surrounding rock mass. The longterm impact of sealing should lead to improvement of the strain levels on the ledges between Level III and Kazanów mid-level chambers. The positive results of applying in the Mine of injection slurries for sealing and stabilizing the rock mass and the construction of the injection node on the surface of the Kosciuszko shaft area have allowed resuming work in the Witos Chambers. The main injection over 1,000 m long pipeline was constructed from the injection node through the Kosciuszko Shaft and along Level III of the mine. The sealing of the Witos Chambers complex was divided into three areas (Fig. 2) separated by backfilling dams. Each region was connected to an injection and venting pipeline, and areas of possible injection material off-flow from backfilling locations were secured. Once that the Chambers are sealed with the use of the pipeline seven bore holes will be drilled from excavations situated above through which the sealing slurry will be administered. The operation will serve to eliminate any voids and re-seal the slag, and it will be conducted until pressures of approximately 0.5 MPa on the bore hole collar is achieved. As past experience indicates, injection slurry formula can be regularly adjusted adequately to the changing geomechanical parameters and the type of sealing work at the Wieliczka Mine. Once that the backfilling and sealing process in the Witos Chambers complex is completed, it shall be necessary to conduct monitoring activities in order to determine the processes occurring in the rock mass after the backfilling. The properties of sealing mixtures qualify those for use in the environment both of salt mines and other mineral ore mines to stabilize the rock mass in the mining-geomechanical context precluding the possibility of weakening the rock mass strength parameters and at the same time sealing the rock mass and the loose material deposited in the excavation.

Command History OPNAV 5750-1 Fiscal Year 2004

DTIC Science & Technology

2006-05-04

highly capable facilities including three hyperbaric 2 chambers, anechoic chambers, auditory and vision laboratories, closed atmosphere test room...3 Hyperbaric Chambers (1 Saturation) • 1000m3 Anechoic Chamber • 140m3 Reverberant Chamber • 10 Audio Testing Booths • Vision Research...Using Hand-Held Personal Digital Assistants (PDAs) in a Hyperbaric Environment and the PDA-based Submarine Escape and Rescue Calculator and

Numerical analysis of the hot-gas-side and coolant-side heat transfer in liquid rocket engine combustors

NASA Technical Reports Server (NTRS)

Wang, Ten-See; Van, Luong

1992-01-01

The objective of this paper are to develop a multidisciplinary computational methodology to predict the hot-gas-side and coolant-side heat transfer and to use it in parametric studies to recommend optimized design of the coolant channels for a regeneratively cooled liquid rocket engine combustor. An integrated numerical model which incorporates CFD for the hot-gas thermal environment, and thermal analysis for the liner and coolant channels, was developed. This integrated CFD/thermal model was validated by comparing predicted heat fluxes with those of hot-firing test and industrial design methods for a 40 k calorimeter thrust chamber and the Space Shuttle Main Engine Main Combustion Chamber. Parametric studies were performed for the Advanced Main Combustion Chamber to find a strategy for a proposed combustion chamber coolant channel design.

Evaluation of Two Surface Sampling Methods for Detection of Erwinia herbicola on a Variety of Materials by Culture and Quantitative PCR▿

PubMed Central

Buttner, Mark P.; Cruz, Patricia; Stetzenbach, Linda D.; Cronin, Tracy

2007-01-01

This research was designed to evaluate surface sampling protocols for use with culture and quantitative PCR (QPCR) amplification assay for detection of the gram-negative bacterial biothreat simulant Erwinia herbicola on a variety of surface materials. Surfaces selected for evaluation were wood laminate, glass and computer monitor screens, metal file cabinets, plastic arena seats, nylon seat cushions, finished concrete flooring, and vinyl tile flooring. Laboratory and test chamber studies were performed to evaluate two sampling methods, a sponge and a macrofoam swab, for detection of E. herbicola on surface materials. In laboratory trials, seven materials were inoculated with a known concentration of E. herbicola cells and samples were collected from the surfaces of the materials to determine sampling efficiencies. Culture analysis was ineffective for assessing E. herbicola collection efficiency because very few culturable cells were obtained from surface samples. QPCR demonstrated that E. herbicola DNA was present in high concentrations on all of the surface samples, and sampling efficiencies ranged from 0.7 to 52.2%, depending on the sampling method and the surface material. The swab was generally more efficient than the sponge for collection of E. herbicola from surfaces. Test chamber trials were also performed in which E. herbicola was aerosolized into the chamber and allowed to settle onto test materials. Surface sampling results supported those obtained in laboratory trials. The results of this study demonstrate the capabilities of QPCR to enhance the detection and enumeration of biocontaminants on surface materials and provide information on the comparability of sampling methods. PMID:17416685

Evaluation of two surface sampling methods for detection of Erwinia herbicola on a variety of materials by culture and quantitative PCR.

PubMed

Buttner, Mark P; Cruz, Patricia; Stetzenbach, Linda D; Cronin, Tracy

2007-06-01

This research was designed to evaluate surface sampling protocols for use with culture and quantitative PCR (QPCR) amplification assay for detection of the gram-negative bacterial biothreat simulant Erwinia herbicola on a variety of surface materials. Surfaces selected for evaluation were wood laminate, glass and computer monitor screens, metal file cabinets, plastic arena seats, nylon seat cushions, finished concrete flooring, and vinyl tile flooring. Laboratory and test chamber studies were performed to evaluate two sampling methods, a sponge and a macrofoam swab, for detection of E. herbicola on surface materials. In laboratory trials, seven materials were inoculated with a known concentration of E. herbicola cells and samples were collected from the surfaces of the materials to determine sampling efficiencies. Culture analysis was ineffective for assessing E. herbicola collection efficiency because very few culturable cells were obtained from surface samples. QPCR demonstrated that E. herbicola DNA was present in high concentrations on all of the surface samples, and sampling efficiencies ranged from 0.7 to 52.2%, depending on the sampling method and the surface material. The swab was generally more efficient than the sponge for collection of E. herbicola from surfaces. Test chamber trials were also performed in which E. herbicola was aerosolized into the chamber and allowed to settle onto test materials. Surface sampling results supported those obtained in laboratory trials. The results of this study demonstrate the capabilities of QPCR to enhance the detection and enumeration of biocontaminants on surface materials and provide information on the comparability of sampling methods.

KSC-99pp0233

NASA Image and Video Library

1999-02-24

KENNEDY SPACE CENTER, FLA. -- Looking as if poised in flight, the saucer-like lid of an altitude chamber is lifted from the floor in the Operations and Checkout Building high bay to its place on top of the chamber. The chamber was recently reactivated, after a 24-year hiatus, to perform leak tests on International Space Station pressurized modules at the launch site. Originally, two chambers were built to test Apollo Program flight hardware. They were last used in 1975 during the Apollo-Soyuz Test Project. After installation of new vacuum pumping equipment and controls, a new control room, and a new rotation handling fixture, the chamber again became operational in February 1999. The chamber, which is 33 feet in diameter and 50 feet tall, is constructed of stainless steel. The first module that will be tested for leaks is the U.S. Laboratory. No date has been determined for the test

Preparation of a Frozen Regolith Simulant Bed for ISRU Component Testing in a Vacuum Chamber

NASA Technical Reports Server (NTRS)

Klenhenz, Julie; Linne, Diane

2013-01-01

In-Situ Resource Utilization (ISRU) systems and components have undergone extensive laboratory and field tests to expose hardware to relevant soil environments. The next step is to combine these soil environments with relevant pressure and temperature conditions. Previous testing has demonstrated how to incorporate large bins of unconsolidated lunar regolith into sufficiently sized vacuum chambers. In order to create appropriate depth dependent soil characteristics that are needed to test drilling operations for the lunar surface, the regolith simulant bed must by properly compacted and frozen. While small cryogenic simulant beds have been created for laboratory tests, this scale effort will allow testing of a full 1m drill which has been developed for a potential lunar prospector mission. Compacted bulk densities were measured at various moisture contents for GRC-3 and Chenobi regolith simulants. Vibrational compaction methods were compared with the previously used hammer compaction, or "Proctor", method. All testing was done per ASTM standard methods. A full 6.13 m3 simulant bed with 6 percent moisture by weight was prepared, compacted in layers, and frozen in a commercial freezer. Temperature and desiccation data was collected to determine logistics for preparation and transport of the simulant bed for thermal vacuum testing. Once in the vacuum facility, the simulant bed will be cryogenically frozen with liquid nitrogen. These cryogenic vacuum tests are underway, but results will not be included in this manuscript.

New Cryogenic Optical Test Capability at Marshall Space Flight Center's Space Optics Manufacturing Technology Center

NASA Technical Reports Server (NTRS)

Kegley, Jeff; Burdine, Robert V. (Technical Monitor)

2002-01-01

A new cryogenic optical testing capability exists at Marshall Space Flight Center's Space Optics Manufacturing Technology Center (SOMTC). SOMTC has been performing optical wavefront testing at cryogenic temperatures since 1999 in the X-ray Cryogenic Test Facility's (XRCF's) large vacuum chamber. Recently the cryogenic optical testing capability has been extended to a smaller vacuum chamber. This smaller horizontal cylindrical vacuum chamber has been outfitted with a helium-cooled liner that can be connected to the facility's helium refrigeration system bringing the existing kilowatt of refrigeration capacity to bear on a 1 meter diameter x 2 meter long test envelope. Cryogenic environments to less than 20 Kelvin are now possible in only a few hours. SOMTC's existing instruments (the Instantaneous Phase-shifting Interferometer (IPI) from ADE Phase-Shift Technologies and the PhaseCam from 4D Vision Technologies) view the optic under test through a 150 mm clear aperture BK-7 window. Since activation and chamber characterization tests in September 2001, the new chamber has been used to perform a cryogenic (less than 30 Kelvin) optical test of a 22.5 cm diameter x 127 cm radius of curvature Si02 mirror, a cryogenic survival (less than 30 Kelvin) test of an adhesive, and a cryogenic cycle (less than 20 Kelvin) test of a ULE mirror. A vibration survey has also been performed on the test chamber. Chamber specifications and performance data, vibration environment data, and limited test results will be presented.

New Cryogenic Optical Test Capability at Marshall Space Flight Center's Space Optics Manufacturing Technology Center

NASA Technical Reports Server (NTRS)

Kegley, Jeff; Stahl, H. Philip (Technical Monitor)

2002-01-01

A new cryogenic optical testing capability exists at Marshall Space Flight Center's Space Optics Manufacturing Technology Center (SOMTC). SOMTC has been performing optical wavefront testing at cryogenic temperatures since 1999 in the X-ray Cryogenic Test Facility's (XRCF's) large vacuum chamber. Recently the cryogenic optical testing capability has been extended to a smaller vacuum chamber. This smaller horizontal cylindrical vacuum chamber has been outfitted with a helium-cooled liner that can be connected to the facility's helium refrigeration system bringing the existing kilowatt of refrigeration capacity to bear on a 1 meter diameter x 2 meter long test envelope. Cryogenic environments to less than 20 Kelvin are now possible in only a few hours. SOMTC's existing instruments (the Instantaneous Phase-shifting Interferometer (IPI) from ADE Phase-Shift Technologies and the PhaseCam from 4D Vision Technologies) view the optic under test through a 150 mm clear aperture BK-7 window. Since activation and chamber characterization tests in September 2001, the new chamber has been used to perform a cryogenic (less than 30 Kelvin) optical test of a 22.5 cm diameter x 127 cm radius of curvature SiO2 mirror, a cryogenic survival (less than 30 Kelvin) test of an adhesive, and a cryogenic cycle (less than 20 Kelvin) test of a ULE mirror. A vibration survey has also been performed on the test chamber. Chamber specifications and performance data, vibration environment data, and limited test results will be presented.

Test Methods for Measuring Material Properties of Composite Materials in all Three Material Axes

DTIC Science & Technology

2012-01-24

perform the environmental tests at cold temperatures, nitrogen tanks were purchased and connected to the environmental chamber via hoses . Fibers of... Braided Composites.” Journal of Composite Materials (30) (1) (1996): 51-68. 2. Graham, Derek. “Buckling of Thick-Section Composite Pressure Hulls

A new ring-shaped graphite monitor ionization chamber

NASA Astrophysics Data System (ADS)

Yoshizumi, M. T.; Caldas, L. V. E.

2010-07-01

A ring-shaped monitor ionization chamber was developed at the Instituto de Pesquisas Energéticas e Nucleares. This ionization chamber presents an entrance window of aluminized polyester foil. The guard ring and collecting electrode are made of graphite coated Lucite plates. The main difference between this new ionization chamber and commercial monitor chambers is its ring-shaped design. The new monitor chamber has a central hole, allowing the passage of the direct radiation beam without attenuation; only the penumbra radiation is measured by the sensitive volume. This kind of ionization chamber design has already been tested, but using aluminium electrodes. By changing the electrode material from aluminium to a graphite coating, an improvement in the chamber response stability was expected. The pre-operational tests, as saturation curve, recombination loss and polarity effect showed satisfactory results. The repeatability and the long-term stability tests were also evaluated, showing good agreement with international recommendations.

MEASUREMENT OF ORGANIC COMPOUND EMISSIONS USING SMALL TEST CHAMBERS

EPA Science Inventory

Organic compounds emitted from a variety of indoor materials have been measured using small (166 L) environmental test chambers. The paper discusses: a) factors to be considered in small chamber testing; b) parameters to be controlled; c) the types of results obtained. The follow...

26th Space Simulation Conference Proceedings. Environmental Testing: The Path Forward

NASA Technical Reports Server (NTRS)

Packard, Edward A.

2010-01-01

Topics covered include: A Multifunctional Space Environment Simulation Facility for Accelerated Spacecraft Materials Testing; Exposure of Spacecraft Surface Coatings in a Simulated GEO Radiation Environment; Gravity-Offloading System for Large-Displacement Ground Testing of Spacecraft Mechanisms; Microscopic Shutters Controlled by cRIO in Sounding Rocket; Application of a Physics-Based Stabilization Criterion to Flight System Thermal Testing; Upgrade of a Thermal Vacuum Chamber for 20 Kelvin Operations; A New Approach to Improve the Uniformity of Solar Simulator; A Perfect Space Simulation Storm; A Planetary Environmental Simulator/Test Facility; Collimation Mirror Segment Refurbishment inside ESA s Large Space; Space Simulation of the CBERS 3 and 4 Satellite Thermal Model in the New Brazilian 6x8m Thermal Vacuum Chamber; The Certification of Environmental Chambers for Testing Flight Hardware; Space Systems Environmental Test Facility Database (SSETFD), Website Development Status; Wallops Flight Facility: Current and Future Test Capabilities for Suborbital and Orbital Projects; Force Limited Vibration Testing of JWST NIRSpec Instrument Using Strain Gages; Investigation of Acoustic Field Uniformity in Direct Field Acoustic Testing; Recent Developments in Direct Field Acoustic Testing; Assembly, Integration and Test Centre in Malaysia: Integration between Building Construction Works and Equipment Installation; Complex Ground Support Equipment for Satellite Thermal Vacuum Test; Effect of Charging Electron Exposure on 1064nm Transmission through Bare Sapphire Optics and SiO2 over HfO2 AR-Coated Sapphire Optics; Environmental Testing Activities and Capabilities for Turkish Space Industry; Integrated Circuit Reliability Simulation in Space Environments; Micrometeoroid Impacts and Optical Scatter in Space Environment; Overcoming Unintended Consequences of Ambient Pressure Thermal Cycling Environmental Tests; Performance and Functionality Improvements to Next Generation Thermal Vacuum Control System; Robotic Lunar Lander Development Project: Three-Dimensional Dynamic Stability Testing and Analysis; Thermal Physical Properties of Thermal Coatings for Spacecraft in Wide Range of Environmental Conditions: Experimental and Theoretical Study; Molecular Contamination Generated in Thermal Vacuum Chambers; Preventing Cross Contamination of Hardware in Thermal Vacuum Chambers; Towards Validation of Particulate Transport Code; Updated Trends in Materials' Outgassing Technology; Electrical Power and Data Acquisition Setup for the CBER 3 and 4 Satellite TBT; Method of Obtaining High Resolution Intrinsic Wire Boom Damping Parameters for Multi-Body Dynamics Simulations; and Thermal Vacuum Testing with Scalable Software Developed In-House.

Reverberation Chamber Uniformity Validation and Radiated Susceptibility Test Procedures for the NASA High Intensity Radiated Fields Laboratory

NASA Technical Reports Server (NTRS)

Koppen, Sandra V.; Nguyen, Truong X.; Mielnik, John J.

2010-01-01

The NASA Langley Research Center's High Intensity Radiated Fields Laboratory has developed a capability based on the RTCA/DO-160F Section 20 guidelines for radiated electromagnetic susceptibility testing in reverberation chambers. Phase 1 of the test procedure utilizes mode-tuned stirrer techniques and E-field probe measurements to validate chamber uniformity, determines chamber loading effects, and defines a radiated susceptibility test process. The test procedure is segmented into numbered operations that are largely software controlled. This document is intended as a laboratory test reference and includes diagrams of test setups, equipment lists, as well as test results and analysis. Phase 2 of development is discussed.

The revised EEMCO guidance for the in vivo measurement of water in the skin.

PubMed

Berardesca, Enzo; Loden, Marie; Serup, Jorgen; Masson, Philippe; Rodrigues, Luis Monteiro

2018-06-20

Noninvasive quantification of stratum corneum water content is widely used in skin research and topical product development. The original EEMCO guidelines on measurements of skin hydration by electrical methods and transepidermal water loss (TEWL) by evaporimeter published in 1997 and 2001 have been revisited and updated with the incorporation of recently available technologies. Electrical methods and open-chamber evaporimeters for measurement of TEWL are still the preferred techniques to measure the water balance in the stratum corneum. The background technology and biophysics of these instruments remain relevant and valid. However, new methods that can image surface hydration and measure depth profiles of dermal water content now available. Open-chamber measurement of TEWL has been supplemented with semiopen and closed chamber probes, which are more robust to environmental influence and therefore convenient to use and more applicable to field studies. However, closed chamber methods interfere with the evaporation of water, and the methods cannot be used for continuous monitoring. Validation of methods with respect to intra- and inter-instrument variation remains challenging. No validation standard or test phantom is available. The established methods for measurement of epidermal water content and TEWL have been supplemented with important new technologies including methods that allow imaging of epidermal water distribution and water depth profiles. A much more complete and sophisticated characterization of the various aspects of the dermal water barrier has been accomplished by means of today's noninvasive techniques; however, instrument standardization and validation remain a challenge. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Vacuum Plasma Spraying Replaces Electrodeposition

NASA Technical Reports Server (NTRS)

Holmes, Richard R.; Power, Chris; Burns, David H.; Daniel, Ron; Mckechnie, Timothy N.

1992-01-01

Vacuum plasma spraying used to fabricate large parts with complicated contours and inner structures, without uninspectable welds. Reduces time, and expense of fabrication. Wall of combustion chamber built up inside of outer nickel-alloy jacket by plasma spraying. Particles of metal sprayed partially melted in plasma gun and thrown at supersonic speed toward deposition surface. Vacuum plasma-spray produces stronger bond between the grooves and covering layer completing channels and wall of combustion chamber. In tests, bond withstood pressure of 20 kpsi, three times allowable limit by old method.

[Development of a microenvironment test chamber for airborne microbe research].

PubMed

Zhan, Ningbo; Chen, Feng; Du, Yaohua; Cheng, Zhi; Li, Chenyu; Wu, Jinlong; Wu, Taihu

2017-10-01

One of the most important environmental cleanliness indicators is airborne microbe. However, the particularity of clean operating environment and controlled experimental environment often leads to the limitation of the airborne microbe research. This paper designed and implemented a microenvironment test chamber for airborne microbe research in normal test conditions. Numerical simulation by Fluent showed that airborne microbes were evenly dispersed in the upper part of test chamber, and had a bottom-up concentration growth distribution. According to the simulation results, the verification experiment was carried out by selecting 5 sampling points in different space positions in the test chamber. Experimental results showed that average particle concentrations of all sampling points reached 10 7 counts/m 3 after 5 minutes' distributing of Staphylococcus aureus , and all sampling points showed the accordant mapping of concentration distribution. The concentration of airborne microbe in the upper chamber was slightly higher than that in the middle chamber, and that was also slightly higher than that in the bottom chamber. It is consistent with the results of numerical simulation, and it proves that the system can be well used for airborne microbe research.

KSC-99pp0229

NASA Image and Video Library

1999-02-23

KENNEDY SPACE CENTER, FLA. -- In the Operations and Checkout Building's high bay, the Rotation Handling Fixture (RHF), with a simulated module attached, is lowered by crane into the altitude chamber below during a test. Under normal operation, the RHF will hold a pressurized module intended for the International Space Station, depositing it into the altitude chamber for leak testing. The chamber was recently reactivated after a 24-year hiatus. Originally, two chambers were built to test Apollo Program flight hardware. They were last used in 1975 during the Apollo-Soyuz Test Project. In 1997, in order to increase the probability of successful missions aboard the ISS, NASA decided to perform leak tests on ISS pressurized modules at the launch site. After installation of new vacuum pumping equipment and controls, a new control room, and a new rotation and handling fixture, the chamber again became operational in February 1999. The chamber, which is 33 feet in diameter and 50 feet tall, is constructed of stainless steel. The rotation handling fixture is aluminum. The first module that will be tested for leaks is the U.S. Laboratory. No date has been determined for the test

KSC-99pp0230

NASA Image and Video Library

1999-02-23

KENNEDY SPACE CENTER, FLA. -- Viewed from inside the altitude chamber in the Operations and Checkout Building's high bay, the Rotation Handling Fixture (RHF), with a simulated module attached, is lowered during a test. Under normal operation, the RHF will hold a pressurized module intended for the International Space Station, depositing it into the altitude chamber for leak testing. The chamber was recently reactivated after a 24-year hiatus. Originally, two chambers were built to test Apollo Program flight hardware. They were last used in 1975 during the Apollo-Soyuz Test Project. In 1997, in order to increase the probability of successful missions aboard the ISS, NASA decided to perform leak tests on ISS pressurized modules at the launch site. After installation of new vacuum pumping equipment and controls, a new control room, and a new rotation and handling fixture, the chamber again became operational in February 1999. The chamber, which is 33 feet in diameter and 50 feet tall, is constructed of stainless steel. The rotation handling fixture is aluminum. The first module that will be tested for leaks is the U.S. Laboratory. No date has been determined for the test

Cyclic fatigue analysis of rocket thrust chambers. Volume 1: OFHC copper chamber low cycle fatigue

NASA Technical Reports Server (NTRS)

Miller, R. W.

1974-01-01

A three-dimensional finite element elasto-plastic strain analysis was performed for the throat section of a regeneratively cooled rocket combustion chamber. The analysis employed the RETSCP finite element computer program. The analysis included thermal and pressure loads, and the effects of temperature dependent material properties, to determine the strain range corresponding to the chamber operating cycle. The analysis was performed for chamber configuration and operating conditions corresponding to a hydrogen-oxygen combustion chamber which was fatigue tested to failure. The computed strain range at typical chamber operating conditions was used in conjunction with oxygen-free, high-conductivity (OHFC) copper isothermal fatigue test data to predict chamber low-cycle fatigue life.

Evaluation of the Dual-Chamber Pen Design for the Injection of Exenatide Once Weekly for the Treatment of Type 2 Diabetes

PubMed Central

LaRue, Susan; Malloy, Jaret

2015-01-01

Background: Exenatide once weekly, an injectable glucagon-like peptide-1 receptor agonist, has been shown to reduce A1C, fasting glucose, and body weight in patients with type 2 diabetes. Exenatide 2.0 mg is dispersed in poly-(D,L-lactide-co-glycolide) polymer microspheres, which require resuspension in aqueous diluent before subcutaneous injection. A single-use, dual-chamber pen was developed to improve the convenience of exenatide once weekly delivery and tested following Food and Drug Administration (FDA) guidance. Methods: Design development goals were established, and validation tests (dose accuracy, torque/force requirements, usability, and ease-of-use) were performed. Dose accuracy was tested under a variety of conditions. After 10 exploratory studies in 329 patients, the final design’s usability and ease-of-use were tested in untrained health care practitioners (HCPs; n = 16) and untrained/trained patients (n = 30/17). Usability testing evaluated completion of multiple setup, dose preparation, and injection steps. Ease-of-use impression was assessed using a scale of 1−7 (1 = very difficult, 7 = very easy). Results: The dual-chamber pen successfully met development goals and delivered target volume (650 µL ± 10%) under tested conditions (mean 644.7–649.3 µL), with torque and force requirements below prespecified maximum values. In the final user study, most participants (≥87%) correctly completed pen setup, dose preparation, and injection steps. Mean ease-of-use scores were 5.8, 6.3, and 6.5 out of 7 in untrained HCPs, untrained patients, and trained patients, respectively. Conclusion: With self-education or minimal training, participants accurately and precisely suspended, mixed, and delivered exenatide-containing microspheres using the dual-chamber pen with high ease-of-use scores. The dual-chamber pen was FDA-approved in February 2014. PMID:25759181

Determination of molecular contamination performance for space chamber tests

NASA Technical Reports Server (NTRS)

Scialdone, J. J.

1973-01-01

The limitations of chamber tests with regard to the molecular contamination of a spacecraft undergoing vacuum test were examined. The molecular flow conditions existing in the chamber and the parameters dictating the degree of contamination were analyzed. Equations and graphs were developed to show the fraction of molecules returning to the spacecraft out of those emitted and to show other chamber flow parameters as a function of chamber and spacecraft surface molecular pumping and geometric configuration. Type and location of instruments required to measure the outgassing, the degree of contamination, and the returning flows are also discussed.

Mechanisms Affecting Performance of the BaBar Resistive Plate Chambers and Searches for Remediation

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

Lu, Changguo

2003-09-19

The BaBar experiment at PEPII relies on the Instrumentation of the Flux Return (IFR) for both muon identification and KL detection. The active detector is composed of Resistive Plate Chambers (RPC's) operated in streamer mode. Since the start of operation the RPC's have suffered persistent efficiency deterioration and dark current increase problems. The ''autopsy'' of bad BaBar RPC's revealed that in many cases uncured Linseed oil droplets had formed on the inner surface of the Bakelite plates, leading to current paths from oil ''stalagmites'' bridging the 2 mm gap. In this paper a possible model of this ''stalagmite'' formation andmore » its effect on the dark current and efficiency of RPC chambers is presented. Laboratory test results strongly support this model. Based upon this model we are searching for solutions to eliminate the unfavorable effect of the oil stalagmites. The lab tests show that the stalagmite resistivity increases dramatically if exposed to the air, an observation that points to a possible way to remedy the damage and increase the efficiency. We have seen that flowing an oxygen gas mixture into the chamber helps to polymerize the uncured linseed oil. Consequently the resistivity of the bridged oil stalagmites increases, as does that of the oil coating on the frame edges and spacers, significantly reducing the RPC dark currents and low-efficiency regions. We have tested this idea on two chambers removed from BaBar because of their low efficiency and high dark current. These test results are reported in the paper, and two other remediation methods also mentioned. We continue to study this problem, and try to find new treatments with permanent improvement.« less

Photodegradation of polyaromatic hydrocarbons in passive air samplers: Field testing different deployment chambers

USGS Publications Warehouse

Bartkow, M.E.; Kennedy, K.E.; Huckins, J.N.; Holling, N.; Komarova, T.; Muller, J.F.

2006-01-01

Semi-permeable membrane devices (SPMDs) were loaded with deuterated anthracene and pyrene as performance reference compounds (PRCs) and deployed at a test site in four different chambers (open and closed box chamber, bowl chamber and cage chamber) for 29 days. The losses of PRCs and the uptake of polyaromatic hydrocarbons (PAHs) from the ambient air were quantified. UV-B levels measured in each deployment chamber indicated that SPMDs would be exposed to the most UV-B in the cage chamber and open box chamber. Significantly less PAHs were quantified in SPMDs deployed in the cage chamber and open box chamber compared to samplers from the other two chambers, suggesting that photodegradation of PAHs had occurred. The loss of PRCs confirmed these results but also showed that photodegradation was occurring in the closed box chamber. The bowl chamber appears to provide the best protection from the influence of direct photodegradation. ?? 2006 Elsevier Ltd. All rights reserved.

WE-DE-201-05: Evaluation of a Windowless Extrapolation Chamber Design and Monte Carlo Based Corrections for the Calibration of Ophthalmic Applicators

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

Hansen, J; Culberson, W; DeWerd, L

Purpose: To test the validity of a windowless extrapolation chamber used to measure surface dose rate from planar ophthalmic applicators and to compare different Monte Carlo based codes for deriving correction factors. Methods: Dose rate measurements were performed using a windowless, planar extrapolation chamber with a {sup 90}Sr/{sup 90}Y Tracerlab RA-1 ophthalmic applicator previously calibrated at the National Institute of Standards and Technology (NIST). Capacitance measurements were performed to estimate the initial air gap width between the source face and collecting electrode. Current was measured as a function of air gap, and Bragg-Gray cavity theory was used to calculate themore » absorbed dose rate to water. To determine correction factors for backscatter, divergence, and attenuation from the Mylar entrance window found in the NIST extrapolation chamber, both EGSnrc Monte Carlo user code and Monte Carlo N-Particle Transport Code (MCNP) were utilized. Simulation results were compared with experimental current readings from the windowless extrapolation chamber as a function of air gap. Additionally, measured dose rate values were compared with the expected result from the NIST source calibration to test the validity of the windowless chamber design. Results: Better agreement was seen between EGSnrc simulated dose results and experimental current readings at very small air gaps (<100 µm) for the windowless extrapolation chamber, while MCNP results demonstrated divergence at these small gap widths. Three separate dose rate measurements were performed with the RA-1 applicator. The average observed difference from the expected result based on the NIST calibration was −1.88% with a statistical standard deviation of 0.39% (k=1). Conclusion: EGSnrc user code will be used during future work to derive correction factors for extrapolation chamber measurements. Additionally, experiment results suggest that an entrance window is not needed in order for an extrapolation chamber to provide accurate dose rate measurements for a planar ophthalmic applicator.« less

Test system for exposing fish to resuspended, contaminated sediment

USGS Publications Warehouse

Cope, W.G.; Wiener, J.G.; Steingraeber, M.T.

1996-01-01

We describe a new test system for exposing fish to resuspended sediments and associated contaminants. Test sediments were resuspended by revolving test chambers on rotating shafts driven by an electric motor. The timing, speed, and duration of test-chamber revolution were controlled by a rheostat and electronic timer. Each chamber held 45 litres of water and accommodated about 49 g of test fish. The system described had three water baths, each holding six test chambers. We illustrate the performance of this system with results from a 28-day test in which juvenile bluegills Lepomis macrochirus were exposed to resuspended, riverine sediments differing in texture and cadmium content. The test had one sediment-free control and five sediment treatments, with three replicates (chambers) per treatment and 25 fish per replicate. Two-thirds (30 litres) of the test water and sediment in each chamber was renewed weekly. The mean concentration of total suspended solids (TSS) did not vary among treatments; the grand-mean TSS in the five sediment treatments was 975 mg litre−1, similar to the target TSS of 1000 mg litre−1. At the end of the test, an average of 50% of the introduced cadmium was associated with the suspended sediment compartment, whereas the filtered (0.45 μm) water contained 0.4% and bluegills 1.8% of the cadmium.

Dynamically controlled crystallization method and apparatus and crystals obtained thereby

NASA Technical Reports Server (NTRS)

Arnowitz, Leonard (Inventor); Steinberg, Emanuel (Inventor)

2003-01-01

A method and apparatus for dynamically controlling the crystallization of molecules including a crystallization chamber (14) or chambers for holding molecules in a precipitant solution, one or more precipitant solution reservoirs (16, 18), communication passages (17, 19) respectively coupling the crystallization chamber(s) with each of the precipitant solution reservoirs, and transfer mechanisms (20, 21, 22, 24, 26, 28) configured to respectively transfer precipitant solution between each of the precipitant solution reservoirs and the crystallization chamber(s). The transfer mechanisms are interlocked to maintain a constant volume of precipitant solution in the crystallization chamber(s). Precipitant solutions of different concentrations are transferred into and out of the crystallization chamber(s) to adjust the concentration of precipitant in the crystallization chamber(s) to achieve precise control of the crystallization process. The method and apparatus can be used effectively to grow crystals under reduced gravity conditions such as microgravity conditions of space, and under conditions of reduced or enhanced effective gravity as induced by a powerful magnetic field.

Computational fluid dynamic (CFD) investigation of thermal uniformity in a thermal cycling based calibration chamber for MEMS

NASA Astrophysics Data System (ADS)

Gui, Xulong; Luo, Xiaobing; Wang, Xiaoping; Liu, Sheng

2015-12-01

Micro-electrical-mechanical system (MEMS) has become important for many industries such as automotive, home appliance, portable electronics, especially with the emergence of Internet of Things. Volume testing with temperature compensation has been essential in order to provide MEMS based sensors with repeatability, consistency, reliability, and durability, but low cost. Particularly, in the temperature calibration test, temperature uniformity of thermal cycling based calibration chamber becomes more important for obtaining precision sensors, as each sensor is different before the calibration. When sensor samples are loaded into the chamber, we usually open the door of the chamber, then place fixtures into chamber and mount the samples on the fixtures. These operations may affect temperature uniformity in the chamber. In order to study the influencing factors of sample-loading on the temperature uniformity in the chamber during calibration testing, numerical simulation work was conducted first. Temperature field and flow field were simulated in empty chamber, chamber with open door, chamber with samples, and chamber with fixtures, respectively. By simulation, it was found that opening chamber door, sample size and number of fixture layers all have effects on flow field and temperature field. By experimental validation, it was found that the measured temperature value was consistent with the simulated temperature value.

MEMS cantilever sensor for THz photoacoustic chemical sensing and pectroscopy

NASA Astrophysics Data System (ADS)

Glauvitz, Nathan E.

Sensitive Microelectromechanical System (MEMS) cantilever designs were modeled, fabricated, and tested to measure the photoacoustic (PA) response of gasses to terahertz (THz) radiation. Surface and bulk micromachining technologies were employed to create the extremely sensitive devices that could detect very small changes in pressure. Fabricated devices were then tested in a custom made THz PA vacuum test chamber where the cantilever deflections caused by the photoacoustic effect were measured with a laser interferometer and iris beam clipped methods. The sensitive cantilever designs achieved a normalized noise equivalent absorption coefficient of 2.83x10-10 cm-1 W Hz-½ using a 25 microW radiation source power and a 1 s sampling time. Traditional gas phase molecular spectroscopy absorption cells are large and bulky. The outcome of this research resulted was a photoacoustic detection method that was virtually independent of the absorption path-length, which allowed the chamber dimensions to be greatly reduced, leading to the possibility of a compact, portable chemical detection and spectroscopy system

Comparison of two radio-frequency plasma sterilization processes using microspot evaluation of microbial inactivation.

PubMed

Lassen, Klaus S; Johansen, Jens E; Grün, Reinar

2006-07-01

In this study, we evaluated gas plasma surface sterilization methods in a specific sterilizer. We have introduced a new monitoring method using 0.4 microm pore size membranes, which in this study gave the information corresponding to 3000 exposed biological indicators per treatment cycle. This enabled us to compare the fraction of inoculates that showed no growth after exposure for 30 different locations in the chamber, and hereby identify weak and strong spots in the chamber with regard to sporicidal effect. Membranes were also used to expose a broad spectrum of soil bacteria for plasma treatment at four different conditions. The organisms were identified using PCR and sequencing. The test showed that Bacillus stearothermophilus spores were inactivated at the slowest rate among the tested microorganisms. Further alpha-proteobacteria (Gram negative) seemed more sensitive than the rest of the tested organisms. The microspot evaluation approach has been a most useful tool in the assessment of sterilization performance in sterilizers that do not have clear measurable parameters related to the sterilization.

Clinical implementation and error sensitivity of a 3D quality assurance protocol for prostate and thoracic IMRT

PubMed Central

Cotter, Christopher; Turcotte, Julie Catherine; Crawford, Bruce; Sharp, Gregory; Mah'D, Mufeed

2015-01-01

This work aims at three goals: first, to define a set of statistical parameters and plan structures for a 3D pretreatment thoracic and prostate intensity‐modulated radiation therapy (IMRT) quality assurance (QA) protocol; secondly, to test if the 3D QA protocol is able to detect certain clinical errors; and third, to compare the 3D QA method with QA performed with single ion chamber and 2D gamma test in detecting those errors. The 3D QA protocol measurements were performed on 13 prostate and 25 thoracic IMRT patients using IBA's COMPASS system. For each treatment planning structure included in the protocol, the following statistical parameters were evaluated: average absolute dose difference (AADD), percent structure volume with absolute dose difference greater than 6% (ADD6), and 3D gamma test. To test the 3D QA protocol error sensitivity, two prostate and two thoracic step‐and‐shoot IMRT patients were investigated. Errors introduced to each of the treatment plans included energy switched from 6 MV to 10 MV, multileaf collimator (MLC) leaf errors, linac jaws errors, monitor unit (MU) errors, MLC and gantry angle errors, and detector shift errors. QA was performed on each plan using a single ion chamber and 2D array of ion chambers for 2D and 3D QA. Based on the measurements performed, we established a uniform set of tolerance levels to determine if QA passes for each IMRT treatment plan structure: maximum allowed AADD is 6%; maximum 4% of any structure volume can be with ADD6 greater than 6%, and maximum 4% of any structure volume may fail 3D gamma test with test parameters 3%/3 mm DTA. Out of the three QA methods tested the single ion chamber performed the worst by detecting 4 out of 18 introduced errors, 2D QA detected 11 out of 18 errors, and 3D QA detected 14 out of 18 errors. PACS number: 87.56.Fc PMID:26699299

KA-111, Phase C, M-1 Propellant Tests: Deflagration in Partial Confinement.

DTIC Science & Technology

1991-07-01

DNA Test Director and Mr. R. !. Flory, Washington Research Center, was Program Coordinator. The DDESB, NDCS , and SSO Technical Monitors for Phase C...to simulate the chamber and access tunnel proportions of the Shallow Underground Tunnel /Chamber Explosion Test conducted at China Lake, CA, in 1988...The chamber and access tunnel at China Lake had the following dimensions (volume, cross-sectional area and length): Chamber: V. - 331.2 m 3 Tunnel : Vt

Space Power Facility Reverberation Chamber Calibration Report

NASA Technical Reports Server (NTRS)

Lewis, Catherine C.; Dolesh, Robert J.; Garrett, Michael J.

2014-01-01

This document describes the process and results of calibrating the Space Environmental Test EMI Test facility at NASA Plum Brook Space Power Facility according to the specifications of IEC61000-4-21 for susceptibility testing from 100 MHz to 40 GHz. The chamber passed the field uniformity test, in both the empty and loaded conditions, making it the world's largest Reverberation Chamber.

The ribbon-cutting ceremony unveils the reactivated altitude chamber inside the O&C high bay

NASA Technical Reports Server (NTRS)

1999-01-01

Inside the Operations and Checkout Building high bay, Center Director Roy Bridges remarks on the accomplishment of the joint NASA/Boeing team in renovating an altitude chamber formerly used on the Apollo program. Project team members, management, media and onlookers are present for the ribbon cutting. The chamber was reactivated, after a 24-year hiatus, to perform leak tests on International Space Station pressurized modules at the launch site. Originally, two chambers were built to test the Apollo command and lunar service modules. They were last used in 1975 during the Apollo-Soyuz Test Project. After installation of new vacuum pumping equipment and controls, a new control room, and a new rotation handling fixture, the chamber again became operational in February 1999. The chamber, which is 33 feet in diameter and 50 feet tall, is constructed of stainless steel. The first module that will be tested for leaks is the U.S. Laboratory. No date has been determined for the test.

Superconductor shields test chamber from ambient magnetic fields

NASA Technical Reports Server (NTRS)

Hildebrandt, A. F.

1965-01-01

Shielding a test chamber for magnetic components enables it to maintain a constant, low magnetic field. The chamber is shielded from ambient magnetic fields by a lead foil cylinder maintained in a superconducting state by liquid helium.

Space shuttle maneuvering engine reusable thrust chamber program. Task 11: Low epsilon stability test report data dump

NASA Technical Reports Server (NTRS)

Pauckert, R. P.

1974-01-01

The stability characteristics of the like-doublet injector were defined over the range of OME chamber pressures and mixture ratios. This was accomplished by bomb testing the injector and cavity configurations in solid wall thrust chamber hardware typical of a flight contour with fuel heated to regenerative chamber outlet temperatures. It was found that stability in the 2600-2800 Hz region depends upon injector hydraulics and on chamber acoustics.

ASTM F739 method for testing the permeation resistance of protective clothing materials: critical analysis with proposed changes in procedure and test-cell design.

PubMed

Anna, D H; Zellers, E T; Sulewski, R

1998-08-01

ASTM (American Society for Testing and Materials) Method F739-96 specifies a test-cell design and procedures for measuring the permeation resistance of chemical protective clothing. Among the specifications are open-loop collection stream flow rates of 0.050 to 0.150 L/min for a gaseous medium. At elevated temperatures the test must be maintained within 1 degree C of the set point. This article presents a critical analysis of the effect of the collection stream flow rate on the measured permeation rate and on the temperature uniformity within the test cell. Permeation tests were conducted on four polymeric glove materials with 44 solvents at 25 degrees C. Flow rates > 0.5 L/min were necessary to obtain accurate steady-state permeation rate (SSPR) values in 25 percent of the tests. At the lower flow rates the true SSPR typically was underestimated by a factor of two or less, but errors of up to 33-fold were observed. No clear relationship could be established between the need for a higher collection stream flow rate and either the vapor pressure or the permeation rate of the solvent, but test results suggest that poor mixing within the collection chamber was a contributing factor. Temperature gradients between the challenge and collection chambers and between the bottom and the top of the collection chamber increased with the water-bath temperature and the collection stream flow rate. Use of a test cell modified to permit deeper submersion reduced the gradients to < or = 0.5 degrees C. It is recommended that all SSPR measurements include verification of the adequacy of the collection stream flow rate. For testing at nonambient temperatures, the modified test cell described here could be used to ensure temperature uniformity throughout the cell.

40 CFR 53.64 - Test procedure: Static fractionator test.

Code of Federal Regulations, 2012 CFR

2012-07-01

... particles of a given size reaching the sampler filter to the mass concentration of particles of the same.... Methods for generating aerosols shall be identical to those prescribed in § 53.62(c)(2). (2) Particle... (with or without an in-line mixing chamber). Validation particle size and quality shall be conducted at...

40 CFR 53.64 - Test procedure: Static fractionator test.

Code of Federal Regulations, 2013 CFR

2013-07-01

... particles of a given size reaching the sampler filter to the mass concentration of particles of the same.... Methods for generating aerosols shall be identical to those prescribed in § 53.62(c)(2). (2) Particle... (with or without an in-line mixing chamber). Validation particle size and quality shall be conducted at...

40 CFR 53.64 - Test procedure: Static fractionator test.

Code of Federal Regulations, 2014 CFR

2014-07-01

... particles of a given size reaching the sampler filter to the mass concentration of particles of the same.... Methods for generating aerosols shall be identical to those prescribed in § 53.62(c)(2). (2) Particle... (with or without an in-line mixing chamber). Validation particle size and quality shall be conducted at...

46 CFR 160.077-19 - Approval Testing-Recreational Hybrid PFD's.

Code of Federal Regulations, 2010 CFR

2010-10-01

... distribution, and inflation medium retention test, UL 1517, sections 18 and 19, except: (i) Recreational hybrid... Method Standard 191, or ASTM D 751 (incorporated by reference, see § 160.077-5). (4) Permeability. The permeability of chamber materials must be determined according to ASTM D 1434 (incorporated by reference, see...

46 CFR 160.077-19 - Approval Testing-Recreational Hybrid PFD's.

Code of Federal Regulations, 2013 CFR

2013-10-01

... distribution, and inflation medium retention test, UL 1517, sections 18 and 19, except: (i) Recreational hybrid... Method Standard 191, or ASTM D 751 (incorporated by reference, see § 160.077-5). (4) Permeability. The permeability of chamber materials must be determined according to ASTM D 1434 (incorporated by reference, see...

46 CFR 160.077-19 - Approval Testing-Recreational Hybrid PFD's.

Code of Federal Regulations, 2011 CFR

2011-10-01

... distribution, and inflation medium retention test, UL 1517, sections 18 and 19, except: (i) Recreational hybrid... Method Standard 191, or ASTM D 751 (incorporated by reference, see § 160.077-5). (4) Permeability. The permeability of chamber materials must be determined according to ASTM D 1434 (incorporated by reference, see...

46 CFR 160.077-19 - Approval Testing-Recreational Hybrid PFD's.

Code of Federal Regulations, 2012 CFR

2012-10-01

... distribution, and inflation medium retention test, UL 1517, sections 18 and 19, except: (i) Recreational hybrid... Method Standard 191, or ASTM D 751 (incorporated by reference, see § 160.077-5). (4) Permeability. The permeability of chamber materials must be determined according to ASTM D 1434 (incorporated by reference, see...

46 CFR 160.077-19 - Approval Testing-Recreational Hybrid PFD's.

Code of Federal Regulations, 2014 CFR

2014-10-01

... distribution, and inflation medium retention test, UL 1517, sections 18 and 19, except: (i) Recreational hybrid... Method Standard 191, or ASTM D 751 (incorporated by reference, see § 160.077-5). (4) Permeability. The permeability of chamber materials must be determined according to ASTM D 1434 (incorporated by reference, see...

Carbon Deposition Model for Oxygen-Hydrocarbon Combustion, Volume 2

NASA Technical Reports Server (NTRS)

Hernandez, R.; Ito, J. I.; Niiya, K. Y.

1987-01-01

Presented are details of the design, fabrication, and testing of subscale hardware used in the evaluation of carbon deposition characteristics of liquid oxygen and three hydrocarbon fuels for both main chamber and preburner/gas generator operating conditions. In main chamber conditions, the deposition of carbon on the combustion chamber wall was investigated at mixture ratios of 2.0 to 4.0 and at chamber pressures of 1000 to 1500 psia. No carbon deposition on chamber walls was detected at these main chamber mixture ratios. In preburner/gas generator operating conditions, the deposition of carbon on the turbine simulator tubes was evaluated at mixture ratios of 0.20 to 0.60 and at chamber pressures of 720 to 1650 psia. The results of the tests showed carbon deposition rate to be a strong function of mixture ratio and a weak function of chamber pressure. Further analyses evaluated the operational concequences of carbon deposition on preburner/gas generator performance. This is Volume 2 of the report, which contains data plots of all the test programs.

Data from one test "Semi-Volatile Organic Compound Small Chamber for bis (2-Ethylhexyl) phthalate in Vinyl Flooring Test 2"

EPA Science Inventory

This data was generated from a small chamber bis(2-ethylhexyl) phthalate (DEHP) emission test. It was to participate an interaboratory study of DEHP emissions from vinyl flooring in a SVOC emission chamber organized by Virginia Polytechnic Institute and State University (VT).

Fire environmental test chamber: its design and development

Treesearch

Clifford J. Auvil

1973-01-01

The Fire Environmental Test Chamber at the Forest Fire Laboratory, Riverside, California, can duplicate under controlled conditions the key factors that affect the flammability of wildland fuels. Within certain limits, it can produce air flow, solar radiation, temperatures, and relative humidity. First developed in 1962, the test chamber has since then undergoneseveral...

Portable automation of static chamber sample collection for quantifying soil gas flux

USDA-ARS?s Scientific Manuscript database

The collection of soil gas flux using the static chamber method is labor intensive. The number of chambers that can be sampled in a given time period is limited by the spacing between chambers and the availability of trained research technicians. However, the static chamber method can limit spatial ...

Cocaine self-administration in social dyads using custom-built operant conditioning chambers.

PubMed

Lacy, Ryan T; Strickland, Justin C; Smith, Mark A

2014-10-30

Traditionally, the analysis of intravenous drug self-administration is limited to conditions in which subjects are tested in isolation. This limits the translational appeal of these studies because drug use in humans often occurs in the presence of others. We used custom-built operant conditioning chambers that allowed social dyads visual, olfactory, auditory, and limited tactile contact while concurrently self-administering cocaine. Male rats were trained to respond according to a fixed interval schedule of reinforcement (with a limited hold) in order to determine if patterns of cocaine (0.75mg/kg/infusion) self-administration became more similar over time in social pairs. Cocaine self-administration was tested across five days according to a 10-min fixed interval schedule (with a 5-min limited hold). Quarter-life values (time at which 25% of responses were emitted per interval) were analyzed using intraclass correlations. The total number of reinforcers obtained did not vary across the five days of testing; however, quarter-life values became progressively more similar between individuals within the social dyads. Standard operant conditioning chambers are unable to assess responding in multiple animals due to their small size, the need to prevent subjects from responding on the lever of their partner, and the need to prevent infusion lines from entangling. By using custom-built social operant conditioning chambers, we assessed the effects of social contact on cocaine self-administration. Social operant conditioning chambers can be used as a preclinical method to examine social influences on drug self-administration under conditions that approximate human substance use. Copyright © 2014 Elsevier B.V. All rights reserved.

Hot fire fatigue testing results for the compliant combustion chamber

NASA Technical Reports Server (NTRS)

Pavli, Albert J.; Kazaroff, John M.; Jankovsky, Robert S.

1992-01-01

A hydrogen-oxygen subscale rocket combustion chamber was designed incorporating an advanced design concept to reduce strain and increase life. The design permits unrestrained thermal expansion of a circumferential direction and, thereby, provides structural compliance during the thermal cycling of hot-fire testing. The chamber was built and test fired at a chamber pressure of 4137 kN/sq m (600 psia) and a hydrogen-oxygen mixture ratio of 6.0. Compared with a conventional milled-channel configuration, the new structurally compliant chamber had a 134 or 287 percent increase in fatigue life, depending on the life predicted for the conventional configuration.

KSC-99pp0234

NASA Image and Video Library

1999-02-24

KENNEDY SPACE CENTER, FLA. -- Workers watch as the 27.5-ton lid is lowered onto the top of an altitude chamber in the Operations and Checkout Building high bay. The chamber was recently reactivated, after a 24-year hiatus, to perform leak tests on International Space Station pressurized modules at the launch site. Originally, two chambers were built to test Apollo Program flight hardware. They were last used in 1975 during the Apollo-Soyuz Test Project. After installation of new vacuum pumping equipment and controls, a new control room, and a new rotation handling fixture, the chamber again became operational in February 1999. The chamber, which is 33 feet in diameter and 50 feet tall, is constructed of stainless steel. The first module that will be tested for leaks is the U.S. Laboratory. No date has been determined for the test

KSC-99pp0232

NASA Image and Video Library

1999-02-24

KENNEDY SPACE CENTER, FLA. -- An overhead crane lifts the saucer-like 27.5-ton lid of an altitude chamber in the Operations and Checkout Building high bay. The chamber was recently reactivated, after a 24-year hiatus, to perform leak tests on International Space Station pressurized modules at the launch site. Originally, two chambers were built to test Apollo Program flight hardware. They were last used in 1975 during the Apollo-Soyuz Test Project. After installation of new vacuum pumping equipment and controls, a new control room, and a new rotation handling fixture, the chamber again became operational in February 1999. The chamber, which is 33 feet in diameter and 50 feet tall, is constructed of stainless steel. The first module that will be tested for leaks is the U.S. Laboratory. No date has been determined for the test

Testing of household products and materials for emission of toluene diisocyanate.

PubMed

Kelly, T J; Myers, J D; Holdren, M W

1999-06-01

Polyurethane products were subjected to chamber testing to determine their emission rates of 2,4- and 2,6-toluene diisocyanate (TDI). The polyurethane (PU) products included carpet padding, furniture cushions, sheet foam, varnishes, and sealants, as well as a commercially-applied water sealant product for concrete that contained up to 4 percent TDI by weight. The PU products were screened in a 9-L glass chamber, under elevated temperature and chamber loading conditions, using both a time-integrated sampling and analysis method specific for TDI and a continuous but non-specific real-time monitor for isocyanates. None of the products normally found in residences showed a positive response in the screening tests, indicating that TDI emissions and consequently toxic effects from such products are negligible. However, the commercially-applied water sealant gave a positive response in the screening test. Further testing of that product at realistic temperatures showed initial TDI emission rates of about 300,000 micrograms/m2/hr, with emissions lasting only one hour or less. At 21 and 27 degrees C, about 1 percent and 5 percent, respectively, of the TDI content of the product was released to the air. The emitted TDI was predominantly the 2,6-isomer, although the TDI originally present in the product was predominantly the 2,4-isomer.

A low-cost touchscreen operant chamber using a Raspberry Pi™.

PubMed

O'Leary, James D; O'Leary, Olivia F; Cryan, John F; Nolan, Yvonne M

2018-03-08

The development of a touchscreen platform for rodent testing has allowed new methods for cognitive testing that have been back-translated from clinical assessment tools to preclinical animal models. This platform for cognitive assessment in animals is comparable to human neuropsychological tests such as those employed by the Cambridge Neuropsychological Test Automated Battery, and thus has several advantages compared to the standard maze apparatuses typically employed in rodent behavioral testing, such as the Morris water maze. These include improved translation of preclinical models, as well as high throughput and the automation of animal testing. However, these systems are relatively expensive, which can impede progress for researchers with limited resources. Here we describe a low-cost touchscreen operant chamber based on the single-board computer, Raspberry Pi TM , which is capable of performing tasks similar to those supported by current state-of-the-art systems. This system provides an affordable alternative for cognitive testing in a touchscreen operant paradigm for researchers with limited funding.

An In-Line Photonic Biosensor for Monitoring of Glucose Concentrations

PubMed Central

Al-Halhouli, Ala'aldeen; Demming, Stefanie; Alahmad, Laila; LIobera, Andreu; Büttgenbach, Stephanus

2014-01-01

This paper presents two PDMS photonic biosensor designs that can be used for continuous monitoring of glucose concentrations. The first design, the internally immobilized sensor, consists of a reactor chamber, micro-lenses and self-alignment structures for fiber optics positioning. This sensor design allows optical detection of glucose concentrations under continuous glucose flow conditions of 33 μL/h based on internal co-immobilization of glucose oxidase (GOX) and horseradish peroxidase (HRP) on the internal PDMS surface of the reactor chamber. For this design, two co-immobilization methods, the simple adsorption and the covalent binding (PEG) methods were tested. Experiments showed successful results when using the covalent binding (PEG) method, where glucose concentrations up to 5 mM with a coefficient of determination (R2) of 0.99 and a limit of detection of 0.26 mM are detectable. The second design is a modified version of the internally immobilized sensor, where a microbead chamber and a beads filling channel are integrated into the sensor. This modification enabled external co-immobilization of enzymes covalently onto functionalized silica microbeads and allows binding a huge amount of HRP and GOX enzymes on the microbeads surfaces which increases the interaction area between immobilized enzymes and the analyte. This has a positive effect on the amount and rate of chemical reactions taking place inside the chamber. The sensor was tested under continuous glucose flow conditions and was found to be able to detect glucose concentrations up to 10 mM with R2 of 0.98 and a limit of detection of 0.7 mM. Such results are very promising for the application in photonic LOC systems used for online analysis. PMID:25157552

Some effects of cyclic induced deformation in rocket thrust chambers

NASA Technical Reports Server (NTRS)

Hannum, N. P.; Quentmeyer, R. J.

1979-01-01

A test program to investigate the deformation process observed in the hot gas wall of rocket thrust chambers was conducted using three different liner materials. Five thrust chambers were cycled to failure using hydrogen and oxygen as propellants at a chamber pressure of 4.14 MN/m square (600 psia). The deformation was observed nondestructively at midlife points and destructively after failure occurred. The cyclic life results are presented with an accompanying discussion about the types of failure encountered. Data indicating the deformation of the thrust chamber liner as cycles are accumulated are presented for each of the test thrust chambers.

High-sensitivity Leak-testing Method with High-Resolution Integration Technique

NASA Astrophysics Data System (ADS)

Fujiyoshi, Motohiro; Nonomura, Yutaka; Senda, Hidemi

A high-resolution leak-testing method named HR (High-Resolution) Integration Technique has been developed for MEMS (Micro Electro Mechanical Systems) sensors such as a vibrating angular-rate sensor housed in a vacuum package. Procedures of the method to obtain high leak-rate resolution were as follows. A package filled with helium gas was kept in a small accumulation chamber to accumulate helium gas leaking from the package. After the accumulation, the accumulated helium gas was introduced into a mass spectrometer in a short period of time, and the flux of the helium gas was measured by the mass spectrometer as a transient phenomenon. The leak-rate of the package was calculated from the detected transient waveform of the mass spectrometer and the accumulation time of the helium gas in the accumulation chamber. Because the density of the helium gas in the vacuum chamber increased and the accumulated helium gas was measured in a very short period of time with the mass spectrometer, the peak strength of the transient waveform became high and the signal to noise ratio was much improved. The detectable leak-rate resolution of the technique reached 1×10-15 (Pa·m3/s). This resolution is 103 times superior to that of the conventional helium vacuum integration method. The accuracy of the measuring system was verified with a standard helium gas leak source. The results were well matched between theoretical calculation based on the leak-rate of the source and the experimental results within only 2% error.

Dynamically controlled crystallization method and apparatus and crystals obtained thereby

NASA Technical Reports Server (NTRS)

Arnowitz, Leonard (Inventor); Steinberg, Emanuel (Inventor)

1999-01-01

A method and apparatus for dynamically controlling the crystallization of proteins including a crystallization chamber or chambers for holding a protein in a salt solution, one or more salt solution chambers, two communication passages respectively coupling the crystallization chamber with each of the salt solution chambers, and transfer mechanisms configured to respectively transfer salt solution between each of the salt solution chambers and the crystallization chamber. The transfer mechanisms are interlocked to maintain the volume of salt solution in the crystallization chamber substantially constant. Salt solution of different concentrations is transferred into and out of the crystallization chamber to adjust the salt concentration in the crystallization chamber to achieve precise control of the crystallization process.

KSC-99pp0231

NASA Image and Video Library

1999-02-23

KENNEDY SPACE CENTER, FLA. -- In the Operations and Checkout Building's high bay, the Rotation Handling Fixture (RHF), with a simulated module attached, is viewed from above the altitude chamber into which it was lowered during a test. Under normal operation, the RHF will hold a pressurized module intended for the International Space Station, depositing it into the altitude chamber for leak testing. The chamber was recently reactivated after a 20-year hiatus. Originally, two chambers were built to test Apollo Program flight hardware. They were last used in 1975 during the Apollo-Soyuz Test Project. In 1997, in order to increase the probability of successful missions aboard the ISS, NASA decided to perform leak tests on ISS pressurized modules at the launch site. After installation of new vacuum pumping equipment and controls, a new control room, and a new rotation and handling fixture, the chamber again became operational in February 1999. The chamber, which is 33 feet in diameter and 50 feet tall, is constructed of stainless steel. The rotation handling fixture is aluminum. The first module that will be tested for leaks is the U.S. Laboratory. No date has been determined for the test

Isothermal Dendritic Growth Experiment - Science, engineering, and hardware development for USMP space flights

NASA Technical Reports Server (NTRS)

Glicksman, M. E.; Hahn, R. C.; Koss, M. B.; Tirmizi, S. H.; Selleck, M. E.; Velosa, A.; Winsa, E.

1991-01-01

The Isothermal Dendritic Growth Experiment (IDGE) has been designed to provide microgravity data on dendritic growth for a critical test of theory. This paper updates progress on constructing a crystal growth chamber suitable for space flight. The IDGE chamber is constructed from glass and stainless steel and is hermetically sealed by electron beam welds and glass-metal seals. Initial tests of the chambers sample's melting point plateau show that the new chamber design is capable of preserving the 99.9995 percent purity of succinonitrile. Dendrite growth can be initiated in the center of the IDGE chamber by means of thermo-electric coolers and a capillary injector tube (stinger). The new IDGE chamber is ready for fully integrated tests with the prototype IDGE engineering hardware at NASA's Lewis Research Center.

The sensitivity of relative toxicity rankings by the USF/NASA test method to some test variables

NASA Technical Reports Server (NTRS)

Hilado, C. J.; Labossiere, L. A.; Leon, H. A.; Kourtides, D. A.; Parker, J. A.; Hsu, M.-T. S.

1976-01-01

Pyrolysis temperature and the distance between the source and sensor of effluents are two important variables in tests for relative toxicity. Modifications of the USF/NASA toxicity screening test method to increase the upper temperature limit of pyrolysis, reduce the distance between the sample and the test animals, and increase the chamber volume available for animal occupancy, did not significantly alter rankings of relative toxicity of four representative materials. The changes rendered some differences no longer significant, but did not reverse any rankings. The materials studied were cotton, wool, aromatic polyamide, and polybenzimidazole.

A Study of Mars Dust Environment Simulation at NASA Johnson Space Center Energy Systems Test Area Resource Conversion Test Facility

NASA Technical Reports Server (NTRS)

Chen, Yuan-Liang Albert

1999-01-01

The dust environment on Mars is planned to be simulated in a 20 foot thermal-vacuum chamber at the Johnson Space Center, Energy Systems Test Area Resource Conversion Test Facility in Houston, Texas. This vacuum chamber will be used to perform tests and study the interactions between the dust in Martian air and ISPP hardware. This project is to research, theorize, quantify, and document the Mars dust/wind environment needed for the 20 foot simulation chamber. This simulation work is to support the safety, endurance, and cost reduction of the hardware for the future missions. The Martian dust environment conditions is discussed. Two issues of Martian dust, (1) Dust Contamination related hazards, and (2) Dust Charging caused electrical hazards, are of our interest. The different methods of dust particles measurement are given. The design trade off and feasibility were studied. A glass bell jar system is used to evaluate various concepts for the Mars dust/wind environment simulation. It was observed that the external dust source injection is the best method to introduce the dust into the simulation system. The dust concentration of 30 Mg/M3 should be employed for preparing for the worst possible Martian atmosphere condition in the future. Two approaches thermal-panel shroud for the hardware conditioning are discussed. It is suggested the wind tunnel approach be used to study the dust charging characteristics then to be apply to the close-system cyclone approach. For the operation cost reduction purpose, a dehumidified ambient air could be used to replace the expensive CO2 mixture for some tests.

Air-kerma strength determination of a new directional 103Pd source

PubMed Central

Reed, Joshua L.; DeWerd, Larry A.; Culberson, Wesley S.

2015-01-01

Purpose: A new directional 103Pd planar source array called a CivaSheet™ has been developed by CivaTech Oncology, Inc., for potential use in low-dose-rate (LDR) brachytherapy treatments. The array consists of multiple individual polymer capsules called CivaDots, containing 103Pd and a gold shield that attenuates the radiation on one side, thus defining a hot and cold side. This novel source requires new methods to establish a source strength metric. The presence of gold material in such close proximity to the active 103Pd region causes the source spectrum to be significantly different than the energy spectra of seeds normally used in LDR brachytherapy treatments. In this investigation, the authors perform air-kerma strength (SK) measurements, develop new correction factors for these measurements based on an experimentally verified energy spectrum, and test the robustness of transferring SK to a well-type ionization chamber. Methods: SK measurements were performed with the variable-aperture free-air chamber (VAFAC) at the University of Wisconsin Medical Radiation Research Center. Subsequent measurements were then performed in a well-type ionization chamber. To realize the quantity SK from a directional source with gold material present, new methods and correction factors were considered. Updated correction factors were calculated using the mcnp 6 Monte Carlo code in order to determine SK with the presence of gold fluorescent energy lines. In addition to SK measurements, a low-energy high-purity germanium (HPGe) detector was used to experimentally verify the calculated spectrum, a sodium iodide (NaI) scintillating counter was used to verify the azimuthal and polar anisotropy, and a well-type ionization chamber was used to test the feasibility of disseminating SK values for a directional source within a cylindrically symmetric measurement volume. Results: The UW VAFAC was successfully used to measure the SK of four CivaDots with reproducibilities within 0.3%. Monte Carlo methods were used to calculate the UW VAFAC correction factors and the calculated spectrum emitted from a CivaDot was experimentally verified with HPGe detector measurements. The well-type ionization chamber showed minimal variation in response (<1.5%) as a function of source positioning angle, indicating that an American Association of Physicists in Medicine (AAPM) Accredited Dosimetry Calibration Laboratory calibrated well chamber would be a suitable device to transfer an SK-based calibration to a clinical user. SK per well-chamber ionization current ratios were consistent among the four dots measured. Additionally, the measurements and predictions of anisotropy show uniform emission within the solid angle of the VAFAC, which demonstrates the robustness of the SK measurement approach. Conclusions: This characterization of a new 103Pd directional brachytherapy source helps to establish calibration methods that could ultimately be used in the well-established AAPM Task Group 43 formalism. Monte Carlo methods accurately predict the changes in the energy spectrum caused by the fluorescent x-rays produced in the gold shield. PMID:26632069

Dynamic measurement of speed of sound in n-Heptane by ultrasonics during fuel injections.

PubMed

Minnetti, Elisa; Pandarese, Giuseppe; Evangelisti, Piersavio; Verdugo, Francisco Rodriguez; Ungaro, Carmine; Bastari, Alessandro; Paone, Nicola

2017-11-01

The paper presents a technique to measure the speed of sound in fuels based on pulse-echo ultrasound. The method is applied inside the test chamber of a Zeuch-type instrument used for indirect measurement of the injection rate (Mexus). The paper outlines the pulse-echo method, considering probe installation, ultrasound beam propagation inside the test chamber, typical signals obtained, as well as different processing algorithms. The method is validated in static conditions by comparing the experimental results to the NIST database both for water and n-Heptane. The ultrasonic system is synchronized to the injector so that time resolved samples of speed of sound can be successfully acquired during a series of injections. Results at different operating conditions in n-Heptane are shown. An uncertainty analysis supports the analysis of results and allows to validate the method. Experimental results show that the speed of sound variation during an injection event is less than 1%, so the Mexus model assumption to consider it constant during the injection is valid. Copyright © 2017 Elsevier B.V. All rights reserved.

Tubular copper thrust chamber design study

NASA Technical Reports Server (NTRS)

Masters, A. I.; Galler, D. E.

1992-01-01

The use of copper tubular thrust chambers is particularly important in high performance expander cycle space engines. Tubular chambers have more surface area than flat wall chambers, and this extra surface area provides enhanced heat transfer for additional energy to power the cycle. This paper was divided into two sections: (1) a thermal analysis and sensitivity study; and (2) a preliminary design of a selected thrust chamber configuration. The thermal analysis consisted of a statistical optimization to determine the optimum tube geometry, tube booking, thrust chamber geometry, and cooling routing to achieve the maximum upper limit chamber pressure for a 25,000 pound thrust engine. The preliminary design effort produced a layout drawing of a tubular thrust chamber that is three inches shorter than the Advanced Expander Test Bed (AETB) milled channel chamber but is predicted to provide a five percent increase in heat transfer. Testing this chamber in the AETB would confirm the inherent advantages of tubular chamber construction and heat transfer.

Testing and Results of Human Metabolic Simulation Utilizing Ultrasonic Nebulizer Technology for Water Vapor Generation

NASA Technical Reports Server (NTRS)

Stubbe, Matthew; Curley, Su

2010-01-01

Life support technology must be evaluated thoroughly before ever being implemented into a functioning design. A major concern during that evaluation is safety. The ability to mimic human metabolic loads allows test engineers to evaluate the effectiveness of new technologies without risking injury to any actual humans. The main function of most life support technologies is the removal of carbon dioxide (CO2) and water (H2O) vapor. As such any good human metabolic simulator (HMS) will mimic the human body s ability to produce these items. Introducing CO2 into a test chamber is a very straightforward process with few unknowns so the focus of this particular new HMS design was on the much more complicated process of introducing known quantities of H2O vapor on command. Past iterations of the HMS have utilized steam which is very hard to keep in vapor phase while transporting and injecting into a test chamber. Also steam adds large quantities of heat to any test chamber, well beyond what an actual human does. For the new HMS an alternative approach to water vapor generation was designed utilizing ultrasonic nebulizers as a method for creating water vapor. Ultrasonic technology allows water to be vibrated into extremely tiny pieces (2-5 microns) and evaporate without requiring additional heating. Doing this process inside the test chamber itself allows H2O vapor generation without the unwanted heat and the challenging process of transporting water vapor. This paper presents the design details as well as results of all initial and final acceptance system testing. Testing of the system was performed at a range of known human metabolic rates in both sea-level and reduced pressure environments. This multitude of test points fully defines the systems capabilities as they relate to actual environmental systems testing.

Trade study comparing specimen chamber servicing methods for the Space Station Centrifuge Facility

NASA Technical Reports Server (NTRS)

Calvisi, Michael L.; Sun, Sidney C.

1991-01-01

The Specimen Chamber Service Unit, a component of the Space Station Centrifuge Facility, must provide a clean enclosure on a continuing basis for the facility's plant, rodent and primate specimens. The specimen chambers can become soiled and can require periodic servicing to maintain a clean environment for the specimens. Two methods of servicing the specimen chambers are discussed: washing the chambers with an on-board washer, or disposing of the soiled chambers and replacing them with clean ones. Many of these issues are addressed by developing several servicing options, using either cleaning or replacement as the method of providing clean specimen chambers, and then evaluating each option according to a set of established quantitative and qualitative criteria. Disposing and replacing the Specimen Chambers is preferable to washing them.

Upper Stage Flight Experiment 10K Engine Design and Test Results

NASA Technical Reports Server (NTRS)

Ross, R.; Morgan, D.; Crockett, D.; Martinez, L.; Anderson, W.; McNeal, C.

2000-01-01

A 10,000 lbf thrust chamber was developed for the Upper Stage Flight Experiment (USFE). This thrust chamber uses hydrogen peroxide/JP-8 oxidizer/fuel combination. The thrust chamber comprises an oxidizer dome and manifold, catalyst bed assembly, fuel injector, and chamber/nozzle assembly. Testing of the engine was done at NASA's Stennis Space Center (SSC) to verify its performance and life for future upper stage or Reusable Launch Vehicle applications. Various combinations of silver screen catalyst beds, fuel injectors, and combustion chambers were tested. Results of the tests showed high C* efficiencies (97% - 100%) and vacuum specific impulses of 275 - 298 seconds. With fuel film cooling, heating rates were low enough that the silica/quartz phenolic throat experienced minimal erosion. Mission derived requirements were met, along with a perfect safety record.

Convection pump and method of operation

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

Steinhour, Leif Alexi

2017-07-11

This disclosure provides systems, methods, and apparatus related to a convection pump. In one aspect, an apparatus includes a chamber, the chamber having an inlet at a first end of the chamber and an outlet at a second end of the chamber. The chamber further has a first surface and a second surface, the first surface being opposite to the second surface. A baffle having a substantially helical shape is disposed inside the chamber. A heating device is configured to heat the first surface of the chamber. A cooling device is configured to cool the second surface of the chamber.

A Novel Method for Measuring the Diffusion, Partition and Convective Mass Transfer Coefficients of Formaldehyde and VOC in Building Materials

PubMed Central

Xiong, Jianyin; Huang, Shaodan; Zhang, Yinping

2012-01-01

The diffusion coefficient (D m) and material/air partition coefficient (K) are two key parameters characterizing the formaldehyde and volatile organic compounds (VOC) sorption behavior in building materials. By virtue of the sorption process in airtight chamber, this paper proposes a novel method to measure the two key parameters, as well as the convective mass transfer coefficient (h m). Compared to traditional methods, it has the following merits: (1) the K, D m and h m can be simultaneously obtained, thus is convenient to use; (2) it is time-saving, just one sorption process in airtight chamber is required; (3) the determination of h m is based on the formaldehyde and VOC concentration data in the test chamber rather than the generally used empirical correlations obtained from the heat and mass transfer analogy, thus is more accurate and can be regarded as a significant improvement. The present method is applied to measure the three parameters by treating the experimental data in the literature, and good results are obtained, which validates the effectiveness of the method. Our new method also provides a potential pathway for measuring h m of semi-volatile organic compounds (SVOC) by using that of VOC. PMID:23145156

Systems for column-based separations, methods of forming packed columns, and methods of purifying sample components

DOEpatents

Egorov, Oleg B.; O'Hara, Matthew J.; Grate, Jay W.; Chandler, Darrell P.; Brockman, Fred J.; Bruckner-Lea, Cynthia J.

2000-01-01

The invention encompasses systems for column-based separations, methods of packing and unpacking columns and methods of separating components of samples. In one aspect, the invention includes a method of packing and unpacking a column chamber, comprising: a) packing a matrix material within a column chamber to form a packed column; and b) after the packing, unpacking the matrix material from the column chamber without moving the column chamber. In another aspect, the invention includes a system for column-based separations, comprising: a) a fluid passageway, the fluid passageway comprising a column chamber and a flow path in fluid communication with the column chamber, the flow path being obstructed by a retaining material permeable to a carrier fluid and impermeable to a column matrix material suspended in the carrier fluid, the flow path extending through the column chamber and through the retaining material, the flow path being configured to form a packed column within the column chamber when a suspension of the fluid and the column matrix material is flowed along the flow path; and b) the fluid passageway extending through a valve intermediate the column chamber and the retaining material.

Systems For Column-Based Separations, Methods Of Forming Packed Columns, And Methods Of Purifying Sample Components

DOEpatents

Egorov, Oleg B.; O'Hara, Matthew J.; Grate, Jay W.; Chandler, Darrell P.; Brockman, Fred J.; Bruckner-Lea, Cynthia J.

2006-02-21

The invention encompasses systems for column-based separations, methods of packing and unpacking columns and methods of separating components of samples. In one aspect, the invention includes a method of packing and unpacking a column chamber, comprising: a) packing a matrix material within a column chamber to form a packed column; and b) after the packing, unpacking the matrix material from the column chamber without moving the column chamber. In another aspect, the invention includes a system for column-based separations, comprising: a) a fluid passageway, the fluid passageway comprising a column chamber and a flow path in fluid communication with the column chamber, the flow path being obstructed by a retaining material permeable to a carrier fluid and impermeable to a column matrix material suspended in the carrier fluid, the flow path extending through the column chamber and through the retaining material, the flow path being configured to form a packed column within the column chamber when a suspension of the fluid and the column matrix material is flowed along the flow path; and b) the fluid passageway extending through a valve intermediate the column chamber and the retaining material.

Systems For Column-Based Separations, Methods Of Forming Packed Columns, And Methods Of Purifying Sample Components.

DOEpatents

Egorov, Oleg B.; O'Hara, Matthew J.; Grate, Jay W.; Chandler, Darrell P.; Brockman, Fred J.; Bruckner-Lea, Cynthia J.

2004-08-24

The invention encompasses systems for column-based separations, methods of packing and unpacking columns and methods of separating components of samples. In one aspect, the invention includes a method of packing and unpacking a column chamber, comprising: a) packing a matrix material within a column chamber to form a packed column; and b) after the packing, unpacking the matrix material from the column chamber without moving the column chamber. In another aspect, the invention includes a system for column-based separations, comprising: a) a fluid passageway, the fluid passageway comprising a column chamber and a flow path in fluid communication with the column chamber, the flow path being obstructed by a retaining material permeable to a carrier fluid and impermeable to a column matrix material suspended in the carrier fluid, the flow path extending through the column chamber and through the retaining material, the flow path being configured to form a packed column within the column chamber when a suspension of the fluid and the column matrix material is flowed along the flow path; and b) the fluid passageway extending through a valve intermediate the column chamber and the retaining material.

Surveyor Atlas-Centaur Shroud Venting Structural Test in the Space Power Chambers

NASA Image and Video Library

1967-06-21

Setup of a Surveyor/Atlas/Centaur shroud in the Space Power Chambers for a leak test at the National Aeronautics and Space Administration (NASA) Lewis Research Center. Centaur was a 15,000-pound thrust second-stage rocket designed for the military in 1957 and 1958 by General Dynamics. It was the first major rocket to use the liquid hydrogen technology developed by Lewis in the 1950s. The Centaur Program suffered numerous problems before being transferred to Lewis in 1962. Several test facilities at Lewis’ main campus and Plum Brook Station were built or modified specifically for Centaur, including the Space Power Chambers. In 1961, NASA Lewis management decided to convert its Altitude Wind Tunnel into two large test chambers and later renamed it the Space Power Chambers. The conversion, which took over 2 years, included the removal of the tunnel’s internal components and insertion of bulkheads to seal off the new chambers. The larger chamber, seen here, could simulate altitudes of 100,000 feet. It was used for Centaur shroud separation and propellant management studies until the early 1970s. The leak test in this photograph was likely an attempt to verify that the shroud’s honeycomb shell did not seep any of its internal air when the chamber was evacuated to pressures similar to those found in the upper atmosphere.

Parallel-plate Flow Chamber and Continuous Flow Circuit to Evaluate Endothelial Progenitor Cells under Laminar Flow Shear Stress

PubMed Central

Lane, Whitney O.; Jantzen, Alexandra E.; Carlon, Tim A.; Jamiolkowski, Ryan M.; Grenet, Justin E.; Ley, Melissa M.; Haseltine, Justin M.; Galinat, Lauren J.; Lin, Fu-Hsiung; Allen, Jason D.; Truskey, George A.; Achneck, Hardean E.

2012-01-01

The overall goal of this method is to describe a technique to subject adherent cells to laminar flow conditions and evaluate their response to well quantifiable fluid shear stresses1. Our flow chamber design and flow circuit (Fig. 1) contains a transparent viewing region that enables testing of cell adhesion and imaging of cell morphology immediately before flow (Fig. 11A, B), at various time points during flow (Fig. 11C), and after flow (Fig. 11D). These experiments are illustrated with human umbilical cord blood-derived endothelial progenitor cells (EPCs) and porcine EPCs2,3. This method is also applicable to other adherent cell types, e.g. smooth muscle cells (SMCs) or fibroblasts. The chamber and all parts of the circuit are easily sterilized with steam autoclaving. In contrast to other chambers, e.g. microfluidic chambers, large numbers of cells (> 1 million depending on cell size) can be recovered after the flow experiment under sterile conditions for cell culture or other experiments, e.g. DNA or RNA extraction, or immunohistochemistry (Fig. 11E), or scanning electron microscopy5. The shear stress can be adjusted by varying the flow rate of the perfusate, the fluid viscosity, or the channel height and width. The latter can reduce fluid volume or cell needs while ensuring that one-dimensional flow is maintained. It is not necessary to measure chamber height between experiments, since the chamber height does not depend on the use of gaskets, which greatly increases the ease of multiple experiments. Furthermore, the circuit design easily enables the collection of perfusate samples for analysis and/or quantification of metabolites secreted by cells under fluid shear stress exposure, e.g. nitric oxide (Fig. 12)6. PMID:22297325

Validation of odor concentration from mechanical-biological treatment piles using static chamber and wind tunnel with different wind speed values.

PubMed

Szyłak-Szydłowski, Mirosław

2017-09-01

The basic principle of odor sampling from surface sources is based primarily on the amount of air obtained from a specific area of the ground, which acts as a source of malodorous compounds. Wind tunnels and flux chambers are often the only available, direct method of evaluating the odor fluxes from small area sources. There are currently no widely accepted chamber-based methods; thus, there is still a need for standardization of these methods to ensure accuracy and comparability. Previous research has established that there is a significant difference between the odor concentration values obtained using the Lindvall chamber and those obtained by a dynamic flow chamber. Thus, the present study compares sampling methods using a streaming chamber modeled on the Lindvall cover (using different wind speeds), a static chamber, and a direct sampling method without any screens. The volumes of chambers in the current work were similar, ~0.08 m 3 . This study was conducted at the mechanical-biological treatment plant in Poland. Samples were taken from a pile covered by the membrane. Measured odor concentration values were between 2 and 150 ou E /m 3 . Results of the study demonstrated that both chambers can be used interchangeably in the following conditions: odor concentration is below 60 ou E /m 3 , wind speed inside the Lindvall chamber is below 0.2 m/sec, and a flow value is below 0.011 m 3 /sec. Increasing the wind speed above the aforementioned value results in significant differences in the results obtained between those methods. In all experiments, the results of the concentration of odor in the samples using the static chamber were consistently higher than those from the samples measured in the Lindvall chamber. Lastly, the results of experiments were employed to determine a model function of the relationship between wind speed and odor concentration values. Several researchers wrote that there are no widely accepted chamber-based methods. Also, there is still a need for standardization to ensure full comparability of these methods. The present study compared the existing methods to improve the standardization of area source sampling. The practical usefulness of the results was proving that both examined chambers can be used interchangeably. Statistically similar results were achieved while odor concentration was below 60 ou E /m 3 and wind speed inside the Lindvall chamber was below 0.2 m/sec. Increasing wind speed over these values results in differences between these methods. A model function of relationship between wind speed and odor concentration value was determined.

Thermal comfort of aeroplane seats: influence of different seat materials and the use of laboratory test methods.

PubMed

Bartels, Volkmar T

2003-07-01

This study determined the influence of different cover and cushion materials on the thermal comfort of aeroplane seats. Different materials as well as ready made seats were investigated by the physiological laboratory test methods Skin Model and seat comfort tester. Additionally, seat trials with human test subjects were performed in a climatic chamber. Results show that a fabric cover produces a considerably higher sweat transport than leather. A three-dimensional knitted spacer fabric turns out to be the better cushion alternative in comparison to a moulded foam pad. Results from the physiological laboratory test methods nicely correspond to the seat trials with human test subjects.

Correlating the EMC analysis and testing methods for space systems in MIL-STD-1541A

NASA Technical Reports Server (NTRS)

Perez, Reinaldo J.

1990-01-01

A study was conducted to improve the correlation between the electromagnetic compatibility (EMC) analysis models stated in MIL-STD-1541A and the suggested testing methods used for space systems. The test and analysis methods outlined in MIL-STD-1541A are described, and a comparative assessment of testing and analysis techniques as they relate to several EMC areas is presented. Suggestions on present analysis and test methods are introduced to harmonize and bring the analysis and testing tools in MIL-STD-1541A into closer agreement. It is suggested that test procedures in MIL-STD-1541A must be improved by providing alternatives to the present use of shielded enclosures as the primary site for such tests. In addition, the alternate use of anechoic chambers and open field test sites must be considered.

Boundary cooled rocket engines for space storable propellants

NASA Technical Reports Server (NTRS)

Kesselring, R. C.; Mcfarland, B. L.; Knight, R. M.; Gurnitz, R. N.

1972-01-01

An evaluation of an existing analytical heat transfer model was made to develop the technology of boundary film/conduction cooled rocket thrust chambers to the space storable propellant combination oxygen difluoride/diborane. Critical design parameters were identified and their importance determined. Test reduction methods were developed to enable data obtained from short duration hot firings with a thin walled (calorimeter) chamber to be used quantitatively evaluate the heat absorbing capability of the vapor film. The modification of the existing like-doublet injector was based on the results obtained from the calorimeter firings.

Casting methods

DOEpatents

Marsden, Kenneth C.; Meyer, Mitchell K.; Grover, Blair K.; Fielding, Randall S.; Wolfensberger, Billy W.

2012-12-18

A casting device includes a covered crucible having a top opening and a bottom orifice, a lid covering the top opening, a stopper rod sealing the bottom orifice, and a reusable mold having at least one chamber, a top end of the chamber being open to and positioned below the bottom orifice and a vacuum tap into the chamber being below the top end of the chamber. A casting method includes charging a crucible with a solid material and covering the crucible, heating the crucible, melting the material, evacuating a chamber of a mold to less than 1 atm absolute through a vacuum tap into the chamber, draining the melted material into the evacuated chamber, solidifying the material in the chamber, and removing the solidified material from the chamber without damaging the chamber.

Accelerated Solar-UV Test Chamber

NASA Technical Reports Server (NTRS)

Gupta, A.; Laue, E. G.

1984-01-01

Medium-pressure mercury-vapor lamps provide high ratio of ultraviolet to total power. Chamber for evaluating solar-ultraviolet (UV) radiation damage permits accelerated testing without overheating test specimens.

Emission of biocides from treated materials: test procedures for water and air.

PubMed

Schoknecht, Ute; Wegner, Robby; Horn, Wolfgang; Jann, Oliver

2003-01-01

Methods for the determination of biocide emissions from treated materials into water and air were developed and tested in order to support a comparative ecological assessment of biocidal products. Leaching tests, experiments with simulated rain, extraction cleaning of carpets and emission chamber tests were performed with a series of treated materials. The experiments focused on the effect of changes in the procedure as well as characteristics of the specimens and demonstrate the suitability of the proposed methods for biocides of different product types. It was demonstrated that emissions of biocides into water can be compared on the basis of leaching tests in which the emission kinetics of the active ingredients are recorded. However, the water volume per surface area and the timetable for water changes have to be defined in such tests. Functions of flux rates related to time can be well described for inorganic compounds, whereas modelling of the data is more complicated for organic substances. Emission chamber tests using 20-litre and 23-litre glass exsiccators, originally developed to study volatile organic compounds, were successfully adapted for the investigation of the emission of biocides from treated materials which are usually semi volatile organic compounds. However test parameters and the method of analysis have to be adapted to the substances to be determined. Generally, it was found that the emission curves for the semi volatile organic compounds investigated differ from those of volatile organic compounds.

Biomass shock pretreatment

DOEpatents

Holtzapple, Mark T.; Madison, Maxine Jones; Ramirez, Rocio Sierra; Deimund, Mark A.; Falls, Matthew; Dunkelman, John J.

2014-07-01

Methods and apparatus for treating biomass that may include introducing a biomass to a chamber; exposing the biomass in the chamber to a shock event to produce a shocked biomass; and transferring the shocked biomass from the chamber. In some aspects, the method may include pretreating the biomass with a chemical before introducing the biomass to the chamber and/or after transferring shocked biomass from the chamber.

A hydrogen-oxygen rocket engine coolant passage design program (RECOP) for fluid-cooled thrust chambers and nozzles

NASA Technical Reports Server (NTRS)

Tomsik, Thomas M.

1994-01-01

The design of coolant passages in regeneratively cooled thrust chambers is critical to the operation and safety of a rocket engine system. Designing a coolant passage is a complex thermal and hydraulic problem requiring an accurate understanding of the heat transfer between the combustion gas and the coolant. Every major rocket engine company has invested in the development of thrust chamber computer design and analysis tools; two examples are Rocketdyne's REGEN code and Aerojet's ELES program. In an effort to augment current design capabilities for government and industry, the NASA Lewis Research Center is developing a computer model to design coolant passages for advanced regeneratively cooled thrust chambers. The RECOP code incorporates state-of-the-art correlations, numerical techniques and design methods, certainly minimum requirements for generating optimum designs of future space chemical engines. A preliminary version of the RECOP model was recently completed and code validation work is in progress. This paper introduces major features of RECOP and compares the analysis to design points for the first test case engine; the Pratt & Whitney RL10A-3-3A thrust chamber.

Method and apparatus for processing a test sample to concentrate an analyte in the sample from a solvent in the sample

DOEpatents

Turner, Terry D.; Beller, Laurence S.; Clark, Michael L.; Klingler, Kerry M.

1997-01-01

A method of processing a test sample to concentrate an analyte in the sample from a solvent in the sample includes: a) boiling the test sample containing the analyte and solvent in a boiling chamber to a temperature greater than or equal to the solvent boiling temperature and less than the analyte boiling temperature to form a rising sample vapor mixture; b) passing the sample vapor mixture from the boiling chamber to an elongated primary separation tube, the separation tube having internal sidewalls and a longitudinal axis, the longitudinal axis being angled between vertical and horizontal and thus having an upper region and a lower region; c) collecting the physically transported liquid analyte on the internal sidewalls of the separation tube; and d) flowing the collected analyte along the angled internal sidewalls of the separation tube to and pass the separation tube lower region. The invention also includes passing a turbulence inducing wave through a vapor mixture to separate physically transported liquid second material from vaporized first material. Apparatus are also disclosed for effecting separations. Further disclosed is a fluidically powered liquid test sample withdrawal apparatus for withdrawing a liquid test sample from a test sample container and for cleaning the test sample container.

Method and apparatus for processing a test sample to concentrate an analyte in the sample from a solvent in the sample

DOEpatents

Turner, T.D.; Beller, L.S.; Clark, M.L.; Klingler, K.M.

1997-10-14

A method of processing a test sample to concentrate an analyte in the sample from a solvent in the sample includes: (a) boiling the test sample containing the analyte and solvent in a boiling chamber to a temperature greater than or equal to the solvent boiling temperature and less than the analyte boiling temperature to form a rising sample vapor mixture; (b) passing the sample vapor mixture from the boiling chamber to an elongated primary separation tube, the separation tube having internal sidewalls and a longitudinal axis, the longitudinal axis being angled between vertical and horizontal and thus having an upper region and a lower region; (c) collecting the physically transported liquid analyte on the internal sidewalls of the separation tube; and (d) flowing the collected analyte along the angled internal sidewalls of the separation tube to and pass the separation tube lower region. The invention also includes passing a turbulence inducing wave through a vapor mixture to separate physically transported liquid second material from vaporized first material. Apparatus is also disclosed for effecting separations. Further disclosed is a fluidically powered liquid test sample withdrawal apparatus for withdrawing a liquid test sample from a test sample container and for cleaning the test sample container. 8 figs.

The ribbon-cutting ceremony unveils the reactivated altitude chamber inside the O&C high bay

NASA Technical Reports Server (NTRS)

1999-01-01

Cutting a red ribbon for the unveiling of a newly renovated altitude chamber are (left to right) Tommy Mack, project manager, NASA; Steve Francois, director, Space Station and Shuttle Payloads; Sterling Walker, director, Engineering Development; Roy Bridges, director, Kennedy Space Center; Jay Greene, International Space Station manager for Technical; Michael Terry, project manager, Boeing; and Terry Smith, director of Engineering, Boeing Space Coast Operations. The chamber was reactivated, after a 24-year hiatus, to perform leak tests on International Space Station pressurized modules at the launch site. Originally, two chambers were built to test the Apollo command and lunar service modules. They were last used in 1975 during the Apollo-Soyuz Test Project. After installation of new vacuum pumping equipment and controls, a new control room, and a new rotation handling fixture, the chamber again became operational in February 1999. The chamber, which is 33 feet in diameter and 50 feet tall, is constructed of stainless steel. The first module that will be tested for leaks is the U.S. Laboratory. No date has been determined for the test.

An environmental chamber for investigating the evaporation of volatile chemicals.

PubMed

Dillon, H K; Rumph, P F

1998-03-01

An inexpensive test chamber has been constructed that provides an environment appropriate for testing the effects of temperature and chemical interactions on gaseous emissions from test solutions. Temperature, relative humidity, and ventilation rate can be controlled and a well-mixed atmosphere can be maintained. The system is relatively simple and relies on heated tap water or ice to adjust the temperature. Temperatures ranging from 9 to 21 degrees C have been maintained. At an average temperature of 15.1 degrees C, temperatures at any location within the chamber vary by no more than 0.5 degree C, and the temperature of the test solution within the chamber varies by no more than 0.1 degree C. The temperatures within the chamber are stable enough to generate precise steady-state concentrations. The wind velocities within the chamber are reproducible from run to run. Consequently, the effect of velocity on the rate of evaporation of a test chemical is expected to be uniform from run to run. Steady-state concentrations can be attained in less than 1 hour at an air exchange rate of about 5 per hour.

Formaldehyde emission from particleboard and plywood paneling : measurement, mechanism, and product standards

Treesearch

George E. Myers

1983-01-01

A number of commercial panel products, primarily particleboard and hardwood plywood, were tested for their formaldehyde emission behavior using desiccator, perforator, and dynamic chamber methods. The results were analyzed in terms of the source of formaldehyde observed in the tests (free vs. hydrolytically produced) and the potential utility of the testa as product...

Isothermal dendritic growth experiment: Science, engineering, and hardware development for USMP space flights

NASA Astrophysics Data System (ADS)

Glicksman, M. E.; Hahn, R. C.; Koss, M. B.; Tirmizi, S. H.; Selleck, M. E.; Velosa, A.; Winsa, E.

The Isothermal Dendritic Growth Experiment (IDGE) has been designed to provide microgravity data on dendritic growth for a critical test of theory. This paper updates our progress on constructing a crystal growth chamber suitable for space flight. The IDGE chamber is constructed from glass and stainless steel and is hermetically sealed by electron beam welds and glass-metal seals. Initial tests of the chambers sample's melting point plateau show that the new chamber design is capable of preserving the 99.9995 pct purity of succinonitrile (SCN). One can initiate dendrite growth in the center of the IDGE chamber by means of thermo-electric coolers and a capillary injector tube (stinger). The new IDGE chamber is ready for fully integrated tests with the prototype IDGE engineering hardware at NASA's Lewis Research Center.

Performance of the Satellite Test Assistant Robot in JPL's Space Simulation Facility

NASA Technical Reports Server (NTRS)

Mcaffee, Douglas; Long, Mark; Johnson, Ken; Siebes, Georg

1995-01-01

An innovative new telerobotic inspection system called STAR (the Satellite Test Assistant Robot) has been developed to assist engineers as they test new spacecraft designs in simulated space environments. STAR operates inside the ultra-cold, high-vacuum, test chambers and provides engineers seated at a remote Operator Control Station (OCS) with high resolution video and infrared (IR) images of the flight articles under test. STAR was successfully proof tested in JPL's 25-ft (7.6-m) Space Simulation Chamber where temperatures ranged from +85 C to -190 C and vacuum levels reached 5.1 x 10(exp -6) torr. STAR's IR Camera was used to thermally map the entire interior of the chamber for the first time. STAR also made several unexpected and important discoveries about the thermal processes occurring within the chamber. Using a calibrated test fixture arrayed with ten sample spacecraft materials, the IR camera was shown to produce highly accurate surface temperature data. This paper outlines STAR's design and reports on significant results from the thermal vacuum chamber test.

IN SITU BIOASSAY CHAMBER FOR ASSESSMENT OF SEDIMENT TOXICITY AND BIOACCUMULATION USING BENTHIC INVERTEBRATES

EPA Science Inventory

In this study, we describe the construction of a simple, inexpensive bioassay chamber for testing sediment toxicity (survival and growth) and bioaccumulation under field conditions using the midge Chironomus tentans and the oligochaete Lumbriculus variegatus. The test chamber is ...

Heat pipe technology for advanced rocket thrust chambers

NASA Technical Reports Server (NTRS)

Rousar, D. C.

1971-01-01

The application of heat pipe technology to the design of rocket engine thrust chambers is discussed. Subjects presented are: (1) evaporator wick development, (2) specific heat pipe designs and test results, (3) injector design, fabrication, and cold flow testing, and (4) preliminary thrust chamber design.

A rapid and accurate method, ventilated chamber C-history method, of measuring the emission characteristic parameters of formaldehyde/VOCs in building materials.

PubMed

Huang, Shaodan; Xiong, Jianyin; Zhang, Yinping

2013-10-15

The indoor pollution caused by formaldehyde and volatile organic compounds (VOCs) emitted from building materials poses an adverse effect on people's health. It is necessary to understand and control the behaviors of the emission sources. Based on detailed mass transfer analysis on the emission process in a ventilated chamber, this paper proposes a novel method of measuring the three emission characteristic parameters, i.e., the initial emittable concentration, the diffusion coefficient and the partition coefficient. A linear correlation between the logarithm of dimensionless concentration and time is derived. The three parameters can then be calculated from the intercept and slope of the correlation. Compared with the closed chamber C-history method, the test is performed under ventilated condition thus some commonly-used measurement instruments (e.g., GC/MS, HPLC) can be applied. While compared with other methods, the present method can rapidly and accurately measure the three parameters, with experimental time less than 12h and R(2) ranging from 0.96 to 0.99 for the cases studied. Independent experiment was carried out to validate the developed method, and good agreement was observed between the simulations based on the determined parameters and experiments. The present method should prove useful for quick characterization of formaldehyde/VOC emissions from indoor materials. Copyright © 2013 Elsevier B.V. All rights reserved.

Corrosion test cell for bipolar plates

DOEpatents

Weisbrod, Kirk R.

2002-01-01

A corrosion test cell for evaluating corrosion resistance in fuel cell bipolar plates is described. The cell has a transparent or translucent cell body having a pair of identical cell body members that seal against opposite sides of a bipolar plate. The cell includes an anode chamber and an cathode chamber, each on opposite sides of the plate. Each chamber contains a pair of mesh platinum current collectors and a catalyst layer pressed between current collectors and the plate. Each chamber is filled with an electrolyte solution that is replenished with fluid from a much larger electrolyte reservoir. The cell includes gas inlets to each chamber for hydrogen gas and air. As the gases flow into a chamber, they pass along the platinum mesh, through the catalyst layer, and to the bipolar plate. The gas exits the chamber through passageways that provide fluid communication between the anode and cathode chambers and the reservoir, and exits the test cell through an exit port in the reservoir. The flow of gas into the cell produces a constant flow of fresh electrolyte into each chamber. Openings in each cell body is member allow electrodes to enter the cell body and contact the electrolyte in the reservoir therein. During operation, while hydrogen gas is passed into one chamber and air into the other chamber, the cell resistance is measured, which is used to evaluate the corrosion properties of the bipolar plate.

Ethylene monitoring and control system

NASA Technical Reports Server (NTRS)

Nelson, Bruce N. (Inventor); Kanc, James A. (Inventor); Richard, II, Roy V. (Inventor)

2000-01-01

A system that can accurately monitor and control low concentrations of ethylene gas includes a test chamber configured to receive sample gas potentially containing an ethylene concentration and ozone, a detector configured to receive light produced during a reaction between the ethylene and ozone and to produce signals related thereto, and a computer connected to the detector to process the signals to determine therefrom a value of the concentration of ethylene in the sample gas. The supply for the system can include a four way valve configured to receive pressurized gas at one input and a test chamber. A piston is journaled in the test chamber with a drive end disposed in a drive chamber and a reaction end defining with walls of the test chamber a variable volume reaction chamber. The drive end of the piston is pneumatically connected to two ports of the four way valve to provide motive force to the piston. A manifold is connected to the variable volume reaction chamber, and is configured to receive sample gasses from at least one of a plurality of ports connectable to degreening rooms and to supply the sample gas to the reactive chamber for reaction with ozone. The apparatus can be used to monitor and control the ethylene concentration in multiple degreening rooms.

Ethylene monitoring and control system

NASA Technical Reports Server (NTRS)

Nelson, Bruce N. (Inventor); Kane, James A. (Inventor); Richard, II, Roy V. (Inventor)

2001-01-01

A system that can accurately monitor and control low concentrations of ethylene gas includes a test chamber configured to receive sample gas potentially containing an ethylene concentration and ozone, a detector configured to receive light produced during a reaction between the ethylene and ozone and to produce signals related thereto, and a computer connected to the detector to process the signals to determine therefrom a value of the concentration of ethylene in the sample gas. The supply for the system can include a four way valve configured to receive pressurized gas at one input and a test chamber. A piston is journaled in the test chamber with a drive end disposed in a drive chamber and a reaction end defining with walls of the test chamber a variable volume reaction chamber. The drive end of the piston is pneumatically connected to two ports of the four way valve to provide motive force to the piston. A manifold is connected to the variable volume reaction chamber, and is configured to receive sample gasses from at least one of a plurality of ports connectable to degreening rooms and to supply the sample gas to the reactive chamber for reaction with ozone. The apparatus can be used to monitor and control the ethylene concentration in multiple degreening rooms.

Determining Transmission Loss from Measured External and Internal Acoustic Environments

NASA Technical Reports Server (NTRS)

Scogin, Tyler; Smith, A. M.

2012-01-01

An estimate of the internal acoustic environment in each internal cavity of a launch vehicle is needed to ensure survivability of Space Launch System (SLS) avionics. Currently, this is achieved by using the noise reduction database of heritage flight vehicles such as the Space Shuttle and Saturn V for liftoff and ascent flight conditions. Marshall Space Flight Center (MSFC) is conducting a series of transmission loss tests to verify and augment this method. For this test setup, an aluminum orthogrid curved panel representing 1/8th of the circumference of a section of the SLS main structure was mounted in between a reverberation chamber and an anechoic chamber. Transmission loss was measured across the panel using microphones. Data measured during this test will be used to estimate the internal acoustic environments for several of the SLS launch vehicle internal spaces.

Lunar-Mars Life Support Test Project. Phase 2; Human Factors and Crew Interactions

NASA Technical Reports Server (NTRS)

Ming, D. W.; Hurlbert, K. M.; Kirby, G.; Lewis, J. F.; ORear, P.

1997-01-01

Phase 2 of the Lunar-Mars Life Support Test Project was conducted in June and July of 1996 at the NASA Johnson Space Center. The primary objective of Phase 2 was to demonstrate and evaluate an integrated physicochemical air revitalization and regenerative water recovery system capable of sustaining a human crew of four for 30 days inside a closed chamber. The crew (3 males and 1 female) was continuously present inside a chamber throughout the 30-day test. The objective of this paper was to describe crew interactions and human factors for the test. Crew preparations for the test included training and familiarization of chamber systems and accommodations, and medical and psychological evaluations. During the test, crew members provided metabolic loads for the life support systems, performed maintenance on chamber systems, and evaluated human factors inside the chamber. Overall, the four crew members found the chamber to be comfortable for the 30-day test. The crew performed well together and this was attributed in part to team dynamics, skill mix (one commander, two system experts, and one logistics lead), and a complementary mix of personalities. Communication with and support by family, friends, and colleagues were identified as important contributors to the high morale of the crew during the test. Lessons learned and recommendations for future testing are presented by the crew in this paper.

Ammunition for Law Enforcements. Part I. Methodology for Evaluating Relative Stopping Power and Results

DTIC Science & Technology

1979-10-01

expansion, relative stopping power according to one or another formula or test method, penetration, ricochet, and other fragments. In the past, the solution...the data gathered for each test round, in the following documents: a. "Ammunition For Law Enforcement: Part II, Data Obtained for Bullets Penetrating...high velocity testing , chamber pressures exceeded those permissible in standard handguns. For safety, then, Mann test barrels were used. At this point

Results from the FIN-2 formal comparison

NASA Astrophysics Data System (ADS)

Connolly, Paul; Hoose, Corinna; Liu, Xiaohong; Moehler, Ottmar; Cziczo, Daniel; DeMott, Paul

2017-04-01

During the Fifth International Ice Nucleation Workshop (FIN-2) at the AIDA Ice Nucleation facility in Karlsruhe, Germany in March 2015, a formal comparison of ice nucleation measurement methods was conducted. During the experiments the samples of ice nucleating particles were not revealed to the instrument scientists, hence this was referred to as a "blind comparison". The two samples used were later revealed to be Arizona Test Dust and an Argentina soil sample. For these two samples seven mobile ice nucleating particle counters sampled directly from the AIDA chamber or from the aerosol preparation chamber at specified temperatures, whereas filter samples were taken for two offline deposition nucleation instruments. Wet suspension methods for determining IN concentrations were also used with 10 different methods employed. For the wet suspension methods experiments were conducted using INPs collected from the air inside the chambers (impinger sampling) and INPs taken from the bulk samples (vial sampling). Direct comparisons of the ice nucleating particle concentrations are reported as well as derived ice nucleation active site densities. The study highlights the difficulties in performing such analyses, but generally indicates that there is reasonable agreement between the wet suspension techniques. It is noted that ice nucleation efficiency derived from the AIDA chamber (quantified using the ice active surface site density approach) is higher than that for the cold stage techniques. This is both true for the Argentina soil sample and, to a lesser extent, for the Arizona Test Dust sample too. Other interesting effects were noted: for the ATD the impinger sampling demonstrated higher INP efficiency at higher temperatures (>255 K) than the vial sampling, but agreed at the lower temperatures (<255K), whereas the opposite was true for the Argentina soil sample. The results are analysed to better understand the performance of the various techniques and to address any size-sorting effects and / or sampling line loses.

Ion chamber absorbed dose calibration coefficients, N{sub D,w}, measured at ADCLs: Distribution analysis and stability

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

Muir, B. R., E-mail: Bryan.Muir@nrc-cnrc.gc.ca

2015-04-15

Purpose: To analyze absorbed dose calibration coefficients, N{sub D,w}, measured at accredited dosimetry calibration laboratories (ADCLs) for client ionization chambers to study (i) variability among N{sub D,w} coefficients for chambers of the same type calibrated at each ADCL to investigate ion chamber volume fluctuations and chamber manufacturing tolerances; (ii) equivalency of ion chamber calibration coefficients measured at different ADCLs by intercomparing N{sub D,w} coefficients for chambers of the same type; and (iii) the long-term stability of N{sub D,w} coefficients for different chamber types by investigating repeated chamber calibrations. Methods: Large samples of N{sub D,w} coefficients for several chamber types measuredmore » over the time period between 1998 and 2014 were obtained from the three ADCLs operating in the United States. These are analyzed using various graphical and numerical statistical tests for the four chamber types with the largest samples of calibration coefficients to investigate (i) and (ii) above. Ratios of calibration coefficients for the same chamber, typically obtained two years apart, are calculated to investigate (iii) above and chambers with standard deviations of old/new ratios less than 0.3% meet stability requirements for accurate reference dosimetry recommended in dosimetry protocols. Results: It is found that N{sub D,w} coefficients for a given chamber type compared among different ADCLs may arise from differing probability distributions potentially due to slight differences in calibration procedures and/or the transfer of the primary standard. However, average N{sub D,w} coefficients from different ADCLs for given chamber types are very close with percent differences generally less than 0.2% for Farmer-type chambers and are well within reported uncertainties. Conclusions: The close agreement among calibrations performed at different ADCLs reaffirms the Calibration Laboratory Accreditation Subcommittee process of ensuring ADCL conformance with National Institute of Standards and Technology standards. This study shows that N{sub D,w} coefficients measured at different ADCLs are statistically equivalent, especially considering reasonable uncertainties. This analysis of N{sub D,w} coefficients also allows identification of chamber types that can be considered stable enough for accurate reference dosimetry.« less

COMPARISON OF THE SINK CHARACTERISTICS OF THREE FULL-SCALE ENVIRONMENTAL CHAMBERS

EPA Science Inventory

The paper gives results of an investigation of the interaction of vapor-phase organic compounds with the interior surfaces of three large dynamic test chambers. A pattern of adsorption and reemission of the test compounds was observed in all three chambers. Quantitative compari...

A test of the IAEA code of practice for absorbed dose determination in photon and electron beams

NASA Astrophysics Data System (ADS)

Leitner, Arnold; Tiefenboeck, Wilhelm; Witzani, Josef; Strachotinsky, Christian

1990-12-01

The IAEA (International Atomic Energy Agency) code of practice TRS 277 gives recommendations for absorbed dose determination in high energy photon and electron beams based on the use of ionization chambers calibrated in terms of exposure of air kerma. The scope of the work was to test the code for cobalt 60 gamma radiation and for several radiation qualities at four different types of electron accelerators and to compare the ionization chamber dosimetry with ferrous sulphate dosimetry. The results show agreement between the two methods within about one per cent for all the investigated qualities. In addition the response of the TLD capsules of the IAEA/WHO TL dosimetry service was determined.

Cryopumping of hydrogen in vacuum chambers is aided by catalytic oxidation of hydrogen

NASA Technical Reports Server (NTRS)

Childs, J. H.; Grobman, J.; Rayle, W.

1964-01-01

Vacuum test facilities are required for high speed cryopumping of gaseous hydrogen at low pressures. One method involves the catalytic oxidation of hydrogen and condensation of the resulting water on a liquid nitrogen-cooled surface.

Investigation of chamber methods and a micrometeorological mass balance method for quantifying greenhouse gas emissions from animal manure

NASA Astrophysics Data System (ADS)

Park, Kyu-Hyun

Various measurement methods to quantify greenhouse gas (GHG) emissions from manure storage or treatment facilities have been used. However, it is difficult to directly compare emission data measured with different methods, which causes uncertainties in national GHG inventories. In the micrometeorological mass balance (MMB) method, a gas flux consists of a horizontal mean flux (MF) and horizontal turbulent flux (TF) terms. In Chapter 2, methane (GH4 ) TF measurements obtained using a sonic anemometer and a tunable diode laser trace gas analyzer are presented. Contrary to previous studies in wind tunnels and flat-level field conditions, an overestimation of only 0.5% was observed by only considering the MF term. This means the MMB method without consideration of TF is suitable in complex field conditions with uneven topography, and farm buildings. In Chapter 3, the MMB method was compared to a floating chamber method. Of these, the floating chamber method has been extensively used for CH4 flux quantification. The MMB method, although providing advantages such as spatial integration of fluxes, requires fast response trace gas analyzers which are not widely available. The mean ratio of CH4 flux measured with the floating chamber method to that measured using the MMB method was 1.25, ranging from 1.07 to 1.83. Flux overestimation by the floating chamber could have been caused by location of the chamber and potential disturbances by the chamber. Frequent changes of the chamber location, use of several chambers, and/or avoiding chamber placement on 'hot spots' are recommended to decrease flux overestimation. In Chapter 4, CH4 fluxes measured with a mega chamber and eight small chambers during the in-vessel composting phase showed similar temporal variation, while nitrous oxide (N2O) fluxes were, significantly lower for the small chambers. The ratios of CH4 fluxes measured with a mega chamber to eight small chambers during the in-vessel composting phase were 0.72 and 1.01, while the ratios of N2O fluxes were 2.74 and 2.01 during two in-vessel composting batches, respectively. Positioning the small chambers on the center line of the composting channels was suitable for quantifying CH4 fluxes, but was not for N 2O. It is recommended to position some chambers in peripheral regions of the composting channel, in order to capture N2O emissions. Methane and N2O fluxes over the initial 50 d of the curing phase were higher than during the in-vessel composting phase. Methane and N2O emissions during the curing phase contributed 95% and 64%, respectively, to overall CH4 and N2O emissions during the composting process (in-vessel composting phase and curing phase). In comparison to liquid swine manure storage over an equivalent time period, composting was estimated to reduce emissions of GHG on a carbon dioxide equivalent (CO2-eq) basis by 35%, which was mainly contributed by a decrease of CH4 emissions. Composting of liquid swine manure with straw has potential for decreasing GHG emissions.

Associations among methane emission traits measured in the feedlot and in respiration chambers in Angus cattle bred to vary in feed efficiency.

PubMed

Herd, R M; Velazco, J I; Arthur, P F; Hegarty, R F

2016-11-01

The objective of the study was to evaluate associations among animal performance and methane emission traits under feedlot conditions and in respiration chambers in Angus cattle bred to vary in residual feed intake (RFI), which is a measure of feed efficiency. Fifty-nine cattle were tested for feedlot RFI, of which 41 had methane production recorded on an ad libitum grain-based ration in the feedlot, 59 on a restricted grain-based ration in respiration chambers, and 57 on a restricted roughage ration in respiration chambers. The cattle became older and heavier as they went through the different phases of the experiment, but their feed intake (expressed as DMI) and daily emission of enteric methane (methane production rate; MPR) did not increase proportionally, as feed offered was restricted in the respiration chamber tests. Methane emissions by individual animals relative to their DMI were calculated as methane yield (MY; MPR/DMI) and as 2 measures of residual methane production (RMP and RMP), which were calculated as the difference between measured MPR and that predicted from feed intake by 2 different equations. Within each test regime, MPR was positively correlated ( = 0.28 to 0.61) with DMI. Phenotypic correlations for MY, RMP, and RMP between the feedlot test and the restricted grain test ( = 0.40 to 0.43) and between the restricted grain test and the restricted roughage test were moderate ( = 0.36 to 0.41) and moderate to strong between the feedlot test and the restricted roughage test ( = 0.54 to 0.58). These results indicate that the rankings of animals for methane production relative to feed consumed are relatively stable over the 3 test phases. Feedlot feed conversion ratio and RFI were not correlated with MPR in the feedlot test and grain-based chamber test but were negatively correlated with MPR in the chamber roughage test ( = -0.31 and -0.37). Both were negatively correlated with MY and RMP in the feedlot test ( = -0.42 to -0.54) and subsequent chamber roughage test ( = -0.27 to -0.49). Midparent estimated breeding values for RFI tended to be negatively correlated with MY and RMP in the feedlot test ( = -0.27 and -0.27) and were negatively correlated with MY, RMP, and RMP in the chamber roughage test ( = -0.33 to -0.36). These results showed that in young growing cattle, lower RFI was associated with higher MY, RMP, and RMP but had no significant association with MPR.

Freeze-drying process monitoring using a cold plasma ionization device.

PubMed

Mayeresse, Y; Veillon, R; Sibille, P H; Nomine, C

2007-01-01

A cold plasma ionization device has been designed to monitor freeze-drying processes in situ by monitoring lyophilization chamber moisture content. This plasma device, which consists of a probe that can be mounted directly on the lyophilization chamber, depends upon the ionization of nitrogen and water molecules using a radiofrequency generator and spectrometric signal collection. The study performed on this probe shows that it is steam sterilizable, simple to integrate, reproducible, and sensitive. The limitations include suitable positioning in the lyophilization chamber, calibration, and signal integration. Sensitivity was evaluated in relation to the quantity of vials and the probe positioning, and correlation with existing methods, such as microbalance, was established. These tests verified signal reproducibility through three freeze-drying cycles. Scaling-up studies demonstrated a similar product signature for the same product using pilot-scale and larger-scale equipment. On an industrial scale, the method efficiently monitored the freeze-drying cycle, but in a larger industrial freeze-dryer the signal was slightly modified. This was mainly due to the positioning of the plasma device, in relation to the vapor flow pathway, which is not necessarily homogeneous within the freeze-drying chamber. The plasma tool is a relevant method for monitoring freeze-drying processes and may in the future allow the verification of current thermodynamic freeze-drying models. This plasma technique may ultimately represent a process analytical technology (PAT) approach for the freeze-drying process.

Atlas-Centaur Orbiting Astronomical Observatory Shroud Test

NASA Image and Video Library

1968-04-21

Researchers at the National Aeronautics and Space Administration (NASA) Lewis Research Center conducted a series of shroud jettison tests for the second Orbiting Astronomical Observatory (OAO-2) in the Space Power Chambers during April 1968. The Orbiting Astronomical Observatory satellites were designed by Goddard Space Flight Center to study and retrieve ultraviolet data on stars and galaxies which earthbound and atmospheric telescopes could not view due to ozone absorption. The shroud jettison system was tested in the Space Power Chambers. In 1961, NASA Lewis management decided to convert its Altitude Wind Tunnel into two large test chambers and later renamed it the Space Power Chambers. The conversion, which took over two years, included removing the tunnel’s internal components and inserting bulkheads to seal off the new chambers. The larger chamber, seen here, could simulate altitudes of 100,000 feet. These chambers were used for a variety of tests on the Centaur second-stage rocket until the early 1970s. The first OAO mission in 1965 failed due to problems with the satellite. OAO-2 would be launched on an Atlas/Centaur with a modified Agena shroud. The new shroud was 18 feet longer than the normal Centaur payload shrouds. This new piece of hardware was successfully qualified during three tests at 90,000 feet altitude in the Space Power Chambers in April 1968. For the first time, x-rays were used to verify the payload clearance once the shroud was sealed. OAO-2 was launched on December 7, 1968 and proved to be an extremely successful mission.

Three-dimensional particle simulation of back-sputtered carbon in electric propulsion test facility

NASA Astrophysics Data System (ADS)

Zheng, Hongru; Cai, Guobiao; Liu, Lihui; Shang, Shengfei; He, Bijiao

2017-03-01

The back-sputtering deposition on thruster surface caused by ion bombardment on chamber wall material affects the performance of thrusters during the ground based electric propulsion endurance tests. In order to decrease the back-sputtering deposition, most of vacuum chambers applied in electric propulsion experiments are equipped with anti-sputtering targets. In this paper, a three-dimensional model of plume experimental system (PES) including double layer anti-sputtering target is established. Simulation cases are made to simulate the plasma environment and sputtering effects when an ion thruster is working. The particle in cell (PIC) method and direct simulation Monte Carlo (DSMC) method is used to calculate the velocity and position of particles. Yamamura's model is used to simulate the sputtering process. The distribution of sputtered anti-sputtering target material is presented. The results show that the double layer anti-sputtering target can significantly reduce the deposition on thruster surface. The back-sputtering deposition rates on thruster exit surface for different cases are compared. The chevrons on the secondary target are rearranged to improve its performance. The position of secondary target has relation with the ion beam divergence angle, and the radius of the vacuum chamber. The back-sputtering deposition rate is lower when the secondary target covers the entire ion beam.

Design of an exposure chamber to test samplers used in the evaluation of personal exposure to nanoparticles

NASA Astrophysics Data System (ADS)

Amin, R.; Izadi, H.; Quémerais, B.

2015-05-01

The aim of this study was to design a laboratory size exposure chamber for the testing of samplers used to collect personal exposure samples for nanoparticles. A polyethylene cylindrical container with a diameter of 42 cm and height of 60 cm was used as the testing chamber. The chamber was divided into 2 parts by an aluminium honey comb. Particles generated using a 1 jet Collison nebulizer (BGI) operating at a flow rate of 4L/min were inserted into the chamber via a tube located near to the top of the chamber. A heater was inserted just after the nebulizer to avoid condensation of water in the tubing, and dilution air, running at 10L/min was inserted just after the heater. As particle charge can dramatically affect sampling a particle neutralizer was attached to the generation system so as to neutralize the particles before they enter the chamber. A diffusion dryer was used to remove any water from the air stream prior to enter the chamber. A fan was used to mix and distribute the generated particles. After generation and mixing, the particles passed through the aluminium honeycomb which is essential to eliminate any turbulent or unwanted air flow. Six sampling ports along with a pressure gauge were placed on the walls 15 cm from the bottom of the chamber. The pressure gauge was added to ensure the desired pressure is achieved during sampling. The sampling ports allowed for the connection of five samplers and sampling pumps as well as the connection of an ultrafine particle counter. The exposure chamber was developed to assess various samplers for carbon nanotubes and cellulose nanocrystals. Results showed that the chamber was working properly and that mixing was sufficiently uniform to test samplers.

Creating the Thermal Environment for Safely Testing the James Webb Space Telescope at the Johnson Space Center's Chamber A

NASA Technical Reports Server (NTRS)

Homan, Jonathan L.; Lauterbach, John; Garcia, Sam

2016-01-01

Chamber A is the largest thermal vacuum chamber at the Johnson Space Center and is one of the largest space environment chambers in the world. The chamber is 19.8 m (65 ft) in diameter and 36.6 m (120 ft) tall and is equipped with cryogenic liquid nitrogen panels (shrouds) and gaseous helium shrouds to create a simulated space environment. The chamber was originally built to support testing of the Apollo Service and Command Module for lunar missions, but underwent major modifications to be able to test the James Webb Space Telescope in a simulated deep space environment. To date seven tests have been performed in preparation of testing the flight optics for the James Webb Space Telescope (JWST). Each test has had a uniquie thermal profile and set of thermal requirements for cooling down and warming up, controlling contamination, and releasing condensed air. These range from temperatures from 335K to 15K, with tight uniformity and controllability for maintining thermal stability and pressure control. One unique requirement for two test was structurally proof loading hardware by creating thermal gradients at specific temperatures. This paper will discuss the thermal requirements and goals of the tests, the original requirements of the chamber thermal systems for planned operation, and how the new requirements were met by the team using the hardware, system flexiblilty, and engineering creativity. It will also discuss the mistakes and successes to meet the unique goals, especially when meeting the thermal proof load.

Rocket thrust chamber thermal barrier coatings

NASA Technical Reports Server (NTRS)

Quentmeyer, R. J.

1985-01-01

Subscale rocket thrust chamber tests were conducted to evaluate the effectiveness and durability of thin yttria stabilized zirconium oxide coatings applied to the thrust chamber hot-gas side wall. The fabrication consisted of arc plasma spraying the ceramic coating and bond coat onto a mandrell and then electrodepositing the copper thrust chamber wall around the coating. Chambers were fabricated with coatings .008, and .005 and .003 inches thick. The chambers were thermally cycled at a chamber pressure of 600 psia using oxygen-hydrogen as propellants and liquid hydrogen as the coolant. The thicker coatings tended to delaminate, early in the cyclic testing, down to a uniform sublayer which remained well adhered during the remaining cycles. Two chambers with .003 inch coatings were subjected to 1500 thermal cycles with no coating loss in the throat region, which represents a tenfold increase in life over identical chambers having no coatings. An analysis is presented which shows that the heat lost to the coolant due to the coating, in a rocket thrust chamber design having a coating only in the throat region, can be recovered by adding only one inch to the combustion chamber length.

Hong's grading for evaluating anterior chamber angle width.

PubMed

Kim, Seok Hwan; Kang, Ja Heon; Park, Ki Ho; Hong, Chul

2012-11-01

To compare Hong's grading method with anterior segment optical coherence tomography (AS-OCT), gonioscopy, and the dark-room prone-position test (DRPT) for evaluating anterior chamber width. The anterior chamber angle was graded using Hong's grading method, and Hong's angle width was calculated from the arctangent of Hong's grades. The correlation between Hong's angle width and AS-OCT parameters was analyzed. The area under the receiver operating characteristic curve (AUC) for Hong's grading method when discriminating between narrow and open angles as determined by gonioscopy was calculated. Correlation analysis was performed between Hong's angle width and intraocular pressure (IOP) changes determined by DRPT. A total of 60 subjects were enrolled. Of these subjects, 53.5 % had a narrow angle. Hong's angle width correlated significantly with the AS-OCT parameters (r = 0.562-0.719, P < 0.01). A Bland-Altman plot showed relatively good agreement between Hong's angle width and the angle width obtained by AS-OCT. The ability of Hong's grading method to discriminate between open and narrow angles was good (AUC = 0.868, 95 % CI 0.756-0.942). A significant linear correlation was found between Hong's angle width and IOP change determined by DRPT (r = -0.761, P < 0.01). Hong's grading method is useful for detecting narrow angles. Hong's grading correlated well with AS-OCT parameters and DRPT.

40 CFR 797.1400 - Fish acute toxicity test.

Code of Federal Regulations, 2011 CFR

2011-07-01

... construction materials, test chambers, and testing apparatus to dilution water or to test solutions prior to... or the leaching of substances from the test facilities into the dilution water or test solution. (5... intermittent passage of test solution or dilution water through a test chamber, or a holding or acclimation...

KSC-99pp0228

NASA Image and Video Library

1999-02-23

KENNEDY SPACE CENTER, FLA. -- In the Operations and Checkout Building's high bay, a crane lifts the Rotation Handling Fixture (RHF) and simulated module during a test. Under normal operation, the RHF will hold a pressurized module intended for the International Space Station, lifting it up and into an altitude chamber for leak testing. The chamber was recently reactivated after a 24-year hiatus. Originally, two chambers were built to test Apollo Program flight hardware. They were last used in 1975 during the Apollo-Soyuz Test Project. In 1997, in order to increase the probability of successful missions aboard the ISS, NASA decided to perform leak tests on ISS pressurized modules at the launch site. After installation of new vacuum pumping equipment and controls, a new control room, and a new rotation and handling fixture, the chamber again became operational in February 1999. The chamber, which is 33 feet in diameter and 50 feet tall, is constructed of stainless steel. The rotation handling fixture is aluminum. The first module that will be tested for leaks is the U.S. Laboratory. No date has been determined for the test

Hot-Fire Test Results of an Oxygen/RP-2 Multi-Element Oxidizer-Rich Staged-Combustion Integrated Test Article

NASA Technical Reports Server (NTRS)

Hulka, J. R.; Protz, C. S.; Garcia, C. P.; Casiano, M. J.; Parton, J. A.

2016-01-01

As part of the Combustion Stability Tool Development project funded by the Air Force Space and Missile Systems Center, the NASA Marshall Space Flight Center was contracted to assemble and hot-fire test a multi-element integrated test article demonstrating combustion characteristics of an oxygen/hydrocarbon propellant oxidizer-rich staged-combustion engine thrust chamber. Such a test article simulates flow through the main injectors of oxygen/kerosene oxidizer-rich staged combustion engines such as the Russian RD-180 or NK-33 engines, or future U.S.-built engine systems such as the Aerojet-Rocketdyne AR-1 engine or the Hydrocarbon Boost program demonstration engine. For the thrust chamber assembly of the test article, several configurations of new main injectors, using relatively conventional gas-centered swirl coaxial injector elements, were designed and fabricated. The design and fabrication of these main injectors are described in a companion paper at this JANNAF meeting. New ablative combustion chambers were fabricated based on hardware previously used at NASA for testing at similar size and pressure. An existing oxygen/RP-1 oxidizer-rich subscale preburner injector from a previous NASA-funded program, along with existing and new inter-connecting hot gas duct hardware, were used to supply the oxidizer-rich combustion products to the oxidizer circuit of the main injector of the thrust chamber. Results from independent hot-fire tests of the preburner injector in a combustion chamber with a sonic throat are described in companion papers at this JANNAF conference. The resulting integrated test article - which includes the preburner, inter-connecting hot gas duct, main injector, and ablative combustion chamber - was assembled at Test Stand 116 at the East Test Area of the NASA Marshall Space Flight Center. The test article was well instrumented with static and dynamic pressure, temperature, and acceleration sensors to allow the collected data to be used for combustion analysis model development. Hot-fire testing was conducted with main combustion chamber pressures ranging from 1400 to 2100 psia, and main combustion chamber mixture ratios ranging from 2.4 to 2.9. Different levels of fuel film cooling injected from the injector face were examined ranging from none to about 12% of the total fuel flow. This paper presents the hot-fire test results of the integrated test article. Combustion performance, stability, thermal, and compatibility characteristics of both the preburner and the thrust chamber are described. Another companion paper at this JANNAF meeting includes additional and more detailed test data regarding the combustion dynamics and stability characteristics.

46 CFR 160.028-4 - Approval and production tests.

Code of Federal Regulations, 2013 CFR

2013-10-01

... the chamber and bore dimensions is not required. (2) Inspections and tests by an independent... the chamber and bore dimensions of the pistol. (2) Fire a dummy cartridge simulating a normal signal....009 (4) Recheck the chamber and bore dimensions. (5) The pistol must fire the signal properly, must...

46 CFR 160.028-4 - Approval and production tests.

Code of Federal Regulations, 2011 CFR

2011-10-01

... the chamber and bore dimensions is not required. (2) Inspections and tests by an independent... the chamber and bore dimensions of the pistol. (2) Fire a dummy cartridge simulating a normal signal....009 (4) Recheck the chamber and bore dimensions. (5) The pistol must fire the signal properly, must...

46 CFR 160.028-4 - Approval and production tests.

Code of Federal Regulations, 2014 CFR

2014-10-01

... the chamber and bore dimensions is not required. (2) Inspections and tests by an independent... the chamber and bore dimensions of the pistol. (2) Fire a dummy cartridge simulating a normal signal....009 (4) Recheck the chamber and bore dimensions. (5) The pistol must fire the signal properly, must...

46 CFR 160.028-4 - Approval and production tests.

Code of Federal Regulations, 2012 CFR

2012-10-01

... the chamber and bore dimensions is not required. (2) Inspections and tests by an independent... the chamber and bore dimensions of the pistol. (2) Fire a dummy cartridge simulating a normal signal....009 (4) Recheck the chamber and bore dimensions. (5) The pistol must fire the signal properly, must...

Air-kerma strength determination of a new directional (103)Pd source.

PubMed

Aima, Manik; Reed, Joshua L; DeWerd, Larry A; Culberson, Wesley S

2015-12-01

A new directional (103)Pd planar source array called a CivaSheet™ has been developed by CivaTech Oncology, Inc., for potential use in low-dose-rate (LDR) brachytherapy treatments. The array consists of multiple individual polymer capsules called CivaDots, containing (103)Pd and a gold shield that attenuates the radiation on one side, thus defining a hot and cold side. This novel source requires new methods to establish a source strength metric. The presence of gold material in such close proximity to the active (103)Pd region causes the source spectrum to be significantly different than the energy spectra of seeds normally used in LDR brachytherapy treatments. In this investigation, the authors perform air-kerma strength (S(K)) measurements, develop new correction factors for these measurements based on an experimentally verified energy spectrum, and test the robustness of transferring S(K) to a well-type ionization chamber. S(K) measurements were performed with the variable-aperture free-air chamber (VAFAC) at the University of Wisconsin Medical Radiation Research Center. Subsequent measurements were then performed in a well-type ionization chamber. To realize the quantity S(K) from a directional source with gold material present, new methods and correction factors were considered. Updated correction factors were calculated using the MCNP 6 Monte Carlo code in order to determine S(K) with the presence of gold fluorescent energy lines. In addition to S(K) measurements, a low-energy high-purity germanium (HPGe) detector was used to experimentally verify the calculated spectrum, a sodium iodide (NaI) scintillating counter was used to verify the azimuthal and polar anisotropy, and a well-type ionization chamber was used to test the feasibility of disseminating S(K) values for a directional source within a cylindrically symmetric measurement volume. The UW VAFAC was successfully used to measure the S(K) of four CivaDots with reproducibilities within 0.3%. Monte Carlo methods were used to calculate the UW VAFAC correction factors and the calculated spectrum emitted from a CivaDot was experimentally verified with HPGe detector measurements. The well-type ionization chamber showed minimal variation in response (<1.5%) as a function of source positioning angle, indicating that an American Association of Physicists in Medicine (AAPM) Accredited Dosimetry Calibration Laboratory calibrated well chamber would be a suitable device to transfer an S(K)-based calibration to a clinical user. S(K) per well-chamber ionization current ratios were consistent among the four dots measured. Additionally, the measurements and predictions of anisotropy show uniform emission within the solid angle of the VAFAC, which demonstrates the robustness of the S(K) measurement approach. This characterization of a new (103)Pd directional brachytherapy source helps to establish calibration methods that could ultimately be used in the well-established AAPM Task Group 43 formalism. Monte Carlo methods accurately predict the changes in the energy spectrum caused by the fluorescent x-rays produced in the gold shield.

Comparison of field olfactometers in a controlled chamber using hydrogen sulfide as the test odorant.

PubMed

McGinley, M A; McGinley, C M

2004-01-01

A standard method for measuring and quantifying odour in the ambient air utilizes a portable odour detecting and measuring device known as a field olfactometer (US Public Health Service Project Grant A-58-541). The field olfactometer dynamically dilutes the ambient air with carbon-filtered air in distinct ratios known as "Dilutions-to-Threshold" dilution factors (D/Ts), i.e. 2, 4, 7, 15, etc. Thirteen US states and several cities in North America currently utilize field olfactometry as a key component of determining compliance to odour regulations and ordinances. A controlled environmental chamber was utilized, with hydrogen sulfide as the known test odorant. A hydrogen sulfide environment was created in this controlled chamber using an Advanced Calibration Designs, Inc. Cal2000 Hydrogen Sulfide Generator. The hydrogen sulfide concentration inside the chamber was monitored using an Arizona Instruments, Inc. Jerome Model 631 H2S Analyzer. When the environmental chamber reached a desired test concentration, test operators entered the chamber. The dilution-to-threshold odour concentration was measured using a Nasal Ranger Field Olfactometer (St Croix Sensory, Inc.) and a Barnebey Sutcliffe Corp. Scentometer. The actual hydrogen sulfide concentration was also measured at the location in the room where the operators were standing while using the two types of field olfactometers. This paper presents a correlation between dilution-to-threshold values (D/T) and hydrogen sulfide ambient concentration. For example, a D/T of 7 corresponds to ambient H2S concentrations of 5.7-15.6 microg/m3 (4-11 ppbv). During this study, no significant difference was found between results obtained using the Scentometer or the Nasal Ranger (r = 0.82). Also, no significant difference was found between results of multiple Nasal Ranger users (p = 0.309). The field olfactometers yielded hydrogen sulfide thresholds of 0.7-3.0 microg/m3 (0.5-2.0 ppbv). Laboratory olfactometry yielded comparable thresholds of 0.64-1.3 microg/m3 (0.45-0.9 ppbv). These thresholds are consistent with published values.

Creating the Deep Space Environment for Testing the James Webb Space Telescope (JWST) at NASA Johnson Space Center's Chamber A

NASA Technical Reports Server (NTRS)

Homan, Jonathan L.; Cerimele, Mary P.; Montz, Michael E.; Bachtel, Russell; Speed, John; O'Rear, Patrick

2013-01-01

Chamber A is the largest thermal vacuum chamber at the Johnson Space Center and is one of the largest space environment chambers in the world. The chamber is 19.8 m (65 ft) in diameter and 36.6 m (120 ft) tall and is equipped with cryogenic liquid nitrogen panels (shrouds) and gaseous helium shrouds to create a simulated space environment. It was originally designed and built in the mid 1960 s to test the Apollo Command and Service Module and several manned tests were conducted on that spacecraft, contributing to the success of the program. The chamber has been used since that time to test spacecraft active thermal control systems, Shuttle DTO, DOD, and ESA hardware in simulated Low Earth Orbit (LEO) conditions. NASA is now moving from LEO towards exploration of locations with environments approaching those of deep space. Therefore, Chamber A has undergone major modifications to enable it to simulate these deeper space environments. Environmental requirements were driven, and modifications were funded by the James Webb Space Telescope program, and this telescope which will orbit Solar/Earth L2, will be the first test article to benefit from the chamber s new capabilities. To accommodate JWST, the Chamber A high vacuum system has been modernized, additional LN2 shrouds have been installed, the liquid nitrogen system has been modified to remove dependency on electrical power and increase its reliability, a new helium shroud/refrigeration system has been installed to create a colder more stable and uniform heat sink, and the controls have been updated to increase the level of automation and improve operator interfaces. Testing of these major modifications was conducted in August of 2012 and this initial test was very successful, with all major systems exceeding their performance requirements. This paper will outline the changes in overall environmental requirements, discuss the technical design data that was used in the decisions leading to the extensive modifications, and describe the new capabilities of the chamber.

Creating the Deep Space Environment for Testing the James Webb Space Telescope at NASA Johnson Space Center's Chamber A

NASA Technical Reports Server (NTRS)

Homan, Jonathan L.; Cerimele, Mary P.; Montz, Michael E.; Bachtel, Russell; Speed, John; O'Rear, Patrick

2013-01-01

Chamber A is the largest thermal vacuum chamber at the Johnson Space Center and is one of the largest space environment chambers in the world. The chamber is 19.8 m (65 ft.) in diameter and 36.6 m (120 ft.) tall and is equipped with cryogenic liquid nitrogen panels (shrouds) and gaseous helium shrouds to create a simulated space environment. It was originally designed and built in the mid 1960 s to test the Apollo Command and Service Module and several manned tests were conducted on that spacecraft, contributing to the success of the program. The chamber has been used since that time to test spacecraft active thermal control systems, Shuttle DTO, DOD, and ESA hardware in simulated Low Earth Orbit (LEO) conditions. NASA is now moving from LEO towards exploration of locations with environments approaching those of deep space. Therefore, Chamber A has undergone major modifications to enable it to simulate these deeper space environments. Environmental requirements were driven, and modifications were funded by the James Webb Space Telescope program, and this telescope, which will orbit Solar/Earth L2, will be the first test article to benefit from the chamber s new capabilities. To accommodate JWST, the Chamber A high vacuum system has been modernized, additional LN2 shrouds have been installed, the liquid nitrogen system has been modified to minimize dependency on electrical power and increase its reliability, a new helium shroud/refrigeration system has been installed to create a colder more stable and uniform heat sink, and the controls have been updated to increase the level of automation and improve operator interfaces. Testing of these major modifications was conducted in August of 2012 and this initial test was very successful, with all major systems exceeding their performance requirements. This paper will outline the changes in overall environmental requirements, discuss the technical design data that was used in the decisions leading to the extensive modifications, and describe the new capabilities of the chamber.

Creating the Deep Space Environment for Testing the James Webb Space Telescope at the Johnson Space Center's Chamber A

NASA Technical Reports Server (NTRS)

Homan, Jonathan L.; Cerimele, Mary P.; Montz, Michael E.

2012-01-01

Chamber A is the largest thermal vacuum chamber at the Johnson Space Center and is one of the largest space environment chambers in the world. The chamber is 19.8 m (65 ft) in diameter and 36.6 m (120 ft) tall and is equipped with cryogenic liquid nitrogen panels (shrouds) and gaseous helium shrouds to create a simulated space environment. It was originally designed and built in the mid 1960's to test the Apollo Command and Service Module and several manned tests were conducted on that spacecraft, contributing to the success of the program. The chamber has been used since that time to test spacecraft active thermal control systems, Shuttle DTO, DOD, and ESA hardware in simulated Low Earth Orbit (LEO) conditions. NASA is now moving from LEO towards exploration of locations with environments approaching those of deep space. Therefore, Chamber A has undergone major modifications to enable it to simulate these deeper space environments. Environmental requirements were driven, and the modifications were funded, by the James Webb Space Telescope program, and this telescope which will orbit Solar/Earth L2, will be the first test article to benefit from the chamber s new capabilities. To accommodate JWST, the Chamber A high vacuum system has been modernized, additional LN2 shrouds have been installed, the liquid nitrogen system has been modified to remove dependency on electrical power and increase its reliability, a new helium shroud/refrigeration system has been installed to create a colder more stable and uniform heat sink and, the controls have been updated to increase the level of automation and improve operator interfaces. Testing of these major modifications was conducted in August 2012 and this initial test was very successful, with all major systems exceeding their performance requirements. This paper will outline the changes in the overall environmental requirements, discuss the technical design data that was used in the decisions leading to the extensive modifications, and describe the new capabilities of the chamber.

Testing of multigap Resistive Plate Chambers for Electron Ion Collider Detector Development

NASA Astrophysics Data System (ADS)

Hamilton, Hannah; Phenix Collaboration

2015-10-01

Despite decades of research on the subject, some details of the spin structure of the nucleon continues to be unknown. To improve our knowledge of the nucleon spin structure, the construction of a new collider is needed. This is one of the primary goals of the proposed Electron Ion Collider (EIC). Planned EIC spectrometers will require good particle identification. This can be provided by time of flight (TOF) detectors with excellent timing resolutions of 10 ps. A potential TOF detector that could meet this requirement is a glass multigap resistive plate chamber (mRPC). These mRPCs can provide excellent timing resolution at a low cost. The current glass mRPC prototypes have a total of twenty 0.1 mm thick gas gaps. In order to test the feasibility of this design, a cosmic test stand was assembled. This stand used the coincidence of scintillators as a trigger, and contains fast electronics. The construction, the method of testing, and the test results of the mRPCs will be presented.

Oxyrase, a method which avoids CO2 in the incubation atmosphere for anaerobic susceptibility testing of antibiotics affected by CO2.

PubMed

Spangler, S K; Appelbaum, P C

1993-02-01

The Oxyrase agar dilution method, with exclusion of CO2 from the environment, was compared with the reference agar dilution method recommended by the National Committee for Clinical Laboratory Standards (anaerobic chamber with 10% CO2) to test the susceptibility of 51 gram-negative and 43 gram-positive anaerobes to azithromycin and erythromycin. With the Oxyrase method, anaerobiosis was achieved by incorporation of the O2-binding enzyme Oxyrase in addition to susceptibility test medium, antibiotic, and enzyme substrates into the upper level of a biplate. Plates were covered with a Brewer lid and incubated in ambient air. With azithromycin, Oxyrase yielded an MIC for 50% of strains tested (MIC50) and MIC90 of 2.0 and 8.0 micrograms/ml, compared to 8.0 and > 32.0 micrograms/ml in standard anaerobic conditions. At a breakpoint of 8.0 micrograms/ml, 90.4% of strains were susceptible to azithromycin with Oxyrase, compared to 53.2% in the chamber. The corresponding erythromycin MIC50 and MIC90 were 1.0 and 8.0 micrograms/ml with Oxyrase, compared to 4.0 and > 32.0 micrograms/ml by the reference method, with 89.3% of strains susceptible at a breakpoint of 4 micrograms/ml with Oxyrase, compared to 60.6% in CO2. Exclusion of CO2 from the anaerobic atmosphere when testing for susceptibility to azalides and macrolides yielded lower MICs, which may lead to a reconsideration of the role played by these compounds in treatment of infections caused by these strains.

Webb Instrument Inside Test Chamber

NASA Image and Video Library

2011-08-18

The Mid-Infrared Instrument, a component of NASA James Webb Space Telescope, underwent testing inside the thermal space test chamber at the Science and Technology Facilities Council Rutherford Appleton Laboratory Space in Oxfordshire, England.

Method for determining hydrogen mobility as a function of temperature in superconducting niobium cavities

DOEpatents

May, Robert [Virginia Beach, VA

2008-03-11

A method for determining the mobility of hydrogen as a function of temperature in superconducting niobium cavities comprising: 1) heating a cavity under test to remove free hydrogen; 2) introducing hydrogen-3 gas into the cavity; 3) cooling the cavity to allow absorption of hydrogen-3; and 4) measuring the amount of hydrogen-3 by: a) cooling the cavity to about 4.degree. K while flowing a known and regulated amount of inert carrier gas such as argon or helium into the cavity; b) allowing the cavity to warm at a stable rate from 4.degree. K to room temperature as it leaves the chamber; and c) directing the exit gas to an ion chamber radiation detector.

New Submersed Chamber for Calibration of Relative Humidity Instruments at HMI/FSB-LPM

NASA Astrophysics Data System (ADS)

Sestan, D.; Zvizdic, D.; Sariri, K.

2018-02-01

This paper gives a detailed description of a new chamber designed for calibration of relative humidity (RH) instruments at Laboratory for Process Measurement (HMI/FSB-LPM). To the present time, the calibrations of RH instruments at the HMI/FSB-LPM were done by comparison method using a climatic chamber of large volume and calibrated dew point hygrometer with an additional thermometer. Since 2010, HMI/FSB-LPM in cooperation with Centre for Metrology and Accreditation in Finland (MIKES) developed the two primary dew point generators which cover the dew point temperature range between - 70 {°}C and 60 {°}C. In order to utilize these facilities for calibrations of the RH instruments, the new chamber was designed, manufactured and installed in the existing system, aiming to extend its range and reduce the related calibration uncertainties. The chamber construction allows its use in a thermostatic bath of larger volume as well as in the climatic chambers. In the scope of this paper, performances of the new chamber were tested while it was submersed in a thermostated bath. The chamber can simultaneously accommodate up to three RH sensors. In order to keep the design of the chamber simple, only cylindrical RH sensors detachable from display units can be calibrated. Possible optimizations are also discussed, and improvements in the design proposed. By using the new chamber, HMI/FSB-LPM reduced the expanded calibration uncertainties (level of confidence 95 %, coverage factor k=2) from 0.6 %rh to 0.25 %rh at 30 %rh (23 {°}C), and from 0.8 %rh to 0.53 %rh at 70 %rh (23 {°}C).

Feasibility Study for a Practical High Rotor Tip Clearance Turbine.

DTIC Science & Technology

GAS TURBINE BLADES ), (* TURBINE BLADES , TOLERANCES(MECHANICS)), (* TURBOFAN ENGINES , GAS TURBINES , AXIAL FLOW TURBINES , AXIAL FLOW TURBINE ROTORS...AERODYNAMIC CONFIGURATIONS, LEAKAGE(FLUID), MEASUREMENT, TEST METHODS, PERFORMANCE( ENGINEERING ), MATHEMATICAL PREDICTION, REDUCTION, PRESSURE, PREDICTIONS, NOZZLE GAS FLOW, COMBUSTION CHAMBER GASES, GAS FLOW.

Chamber for mechanical testing in H2 with observation by neutron scattering

NASA Astrophysics Data System (ADS)

Connolly, Matthew; Bradley, Peter; Slifka, Andrew; Drexler, Elizabeth

2017-06-01

A gas-pressure chamber has been designed, constructed, and tested at a moderate pressure (3.4 MPa, 500 psi) and has the capability of mechanical loading of steel specimens for neutron scattering measurements. The chamber will allow a variety of in situ neutron scattering measurements: in particular, diffraction, quasielastic scattering, inelastic scattering, and imaging. The chamber is compatible with load frames available at the user facilities at the NIST Center for Neutron Research and Oak Ridge National Laboratory Spallation Neutron Source. A demonstration of neutron Bragg edge imaging using the chamber is presented.

KSC-99pp0235

NASA Image and Video Library

1999-02-25

KENNEDY SPACE CENTER, FLA. -- Inside the Operations and Checkout Building high bay, Center Director Roy Bridges remarks on the accomplishment of the joint NASA/Boeing team in renovating an altitude chamber formerly used on the Apollo program. Project team members, management, media and onlookers are present for the ribbon cutting. The chamber was reactivated, after a 24-year hiatus, to perform leak tests on International Space Station pressurized modules at the launch site. Originally, two chambers were built to test the Apollo command and lunar service modules. They were last used in 1975 during the Apollo-Soyuz Test Project. After installation of new vacuum pumping equipment and controls, a new control room, and a new rotation handling fixture, the chamber again became operational in February 1999. The chamber, which is 33 feet in diameter and 50 feet tall, is constructed of stainless steel. The first module that will be tested for leaks is the U.S. Laboratory. No date has been determined for the test

High-pressure calorimeter chamber tests for liquid oxygen/kerosene (LOX/RP-1) rocket combustion

NASA Technical Reports Server (NTRS)

Masters, Philip A.; Armstrong, Elizabeth S.; Price, Harold G.

1988-01-01

An experimental program was conducted to investigate the rocket combustion and heat transfer characteristics of liquid oxygen/kerosene (LOX/RP-1) mixtures at high chamber pressures. Two water-cooled calorimeter chambers of different combustion lengths were tested using 37- and 61-element oxidizer-fuel-oxidizer triplet injectors. The tests were conducted at nominal chamber pressures of 4.1, 8.3, and 13.8 MPa abs (600, 1200, and 2000 psia). Heat flux Q/A data were obtained for the entire calorimeter length for oxygen/fuel mixture ratios of 1.8 to 3.3. Test data at 4.1 MPa abs compared favorably with previous test data from another source. Using an injector with a fuel-rich outer zone reduced the throat heat flux by 47 percent with only a 4.5 percent reduction in the characteristic exhaust velocity efficiency C* sub eff. The throat heat transfer coefficient was reduced approximately 40 percent because of carbon deposits on the chamber wall.

Forward conditioning with wheel running causes place aversion in rats.

PubMed

Masaki, Takahisa; Nakajima, Sadahiko

2008-09-01

Backward pairings of a distinctive chamber as a conditioned stimulus and wheel running as an unconditioned stimulus (i.e., running-then-chamber) can produce a conditioned place preference in rats. The present study explored whether a forward conditioning procedure with these stimuli (i.e., chamber-then-running) would yield place preference or aversion. Confinement of a rat in one of two distinctive chambers was followed by a 20- or 60-min running opportunity, but confinement in the other was not. After four repetitions of this treatment (i.e., differential conditioning), a choice preference test was given in which the rat had free access to both chambers. This choice test showed that the rats given 60-min running opportunities spent less time in the running-paired chamber than in the unpaired chamber. Namely, a 60-min running opportunity after confinement in a distinctive chamber caused conditioned aversion to that chamber after four paired trials. This result was discussed with regard to the opponent-process theory of motivation.

Modernization of NASA's Johnson Space Center Chamber: A Liquid Nitrogen System to Support Cryogenic Vacuum Optical Testing of the James Webb Space Telescope (JWST)

NASA Technical Reports Server (NTRS)

Garcia, Sammy; Homan, Jonathan; Montz, Michael

2016-01-01

NASA is the mission lead for the James Webb Space Telescope (JWST), the next of the “Great Observatories”, scheduled for launch in 2018. It is directly responsible for the integration and test (I&T) program that will culminate in an end-to-end cryo vacuum optical test of the flight telescope and instrument module in Chamber A at NASA Johnson Space Center. Historic Chamber A is the largest thermal vacuum chamber at Johnson Space Center and one of the largest space simulation chambers in the world. Chamber A has undergone a major modernization effort to support the deep cryogenic, vacuum and cleanliness requirements for testing the JWST. This paper describes the steps performed in efforts to convert the existing the 60’s era Liquid Nitrogen System from a forced flow (pumped) process to a natural circulation (thermo-siphon) process. In addition, the paper will describe the dramatic conservation of liquid nitrogen to support the long duration thermal vacuum testing. Lastly, describe the simplistic and effective control system which results in zero to minimal human inputs during steady state conditions.

Rapid Ascent Simulation at NASA-MSFC

NASA Technical Reports Server (NTRS)

Sisco, Jimmy D.

2004-01-01

The Environmental Test Facility (ETF), located at NASA-Marshall Space Flight Center, Huntsville, Alabama, has provided thermal vacuum testing for several major programs since the 1960's. The ETF consists of over 13 thermal vacuum chambers sized and configured to handle the majority of test payloads. The majority of tests require a hard vacuum with heating and cryogenics. NASA's Return-to-Flight program requested testing to simulate a launch from the ground to flight using vacuum, heating and cryogenics. This paper describes an effective method for simulating a launch.

Combustion Science

NASA Image and Video Library

2003-04-01

This photograph depicts one of over thirty tests conducted on the Vortex Combustion Chamber Engine at Marshall Space Flight Center's (MSFC) test stand 115, a joint effort between NASA's MSFC and the U.S. Army AMCOM of Redstone Arsenal. The engine tests were conducted to evaluate an irnovative, "self-cooled", vortex combustion chamber, which relies on tangentially injected propellants from the chamber wall producing centrifugal forces that keep the relatively cold liquid propellants near the wall.

Sorption of Organophosphorus Flame-Retardants on Settled ...

EPA Pesticide Factsheets

Dust is an important sink for indoor air pollutants, such as organophosphorus flame-retardants (OPFRs) that are used as additives in industrial and consumer products including electrical and electronic products, furniture, plastics, textile, and building/construction materials. This research investigated the sorption of OPFRs, tris(2-chloroethyl) phosphate (TCEP), tris(1-chlor-2-propyl) phosphate (TCPP), and tris(1,3-dichloro-2-propyl) phosphate (TDCPP) on settled Arizona Test Dust (ATD) using a dual small chamber system. During the test, seven free film release paper dust trays covered with ATD were placed in the sink test chamber. Constant gas phase OPFRs from the source chamber were dosed into the test chamber. The dust evenly spread on each dust tray was removed from the test chamber at different exposure times to determine the amount of OPFRs absorbed by the dust. The ATD has been characterized for a nominal particle size and surface area. The mass of dust on each of seven dust trays was weighed before the dust was placed inside the sink chamber. OPFRs concentrations at the inlet and faceplate of the test chamber were monitored by collecting polyurethane foam (PUF) samples. The OPFR exposed dust and PUF samples were extracted by 1:1 ethyl acetate/methylene chloride and analyzed on GC/MS. The data were used to calculate the OPFR sorption concentration on the dust through dust/air partition. Settled dust can adsorb OPFR from air. The sorption concentration wa

Project NEO Specific Impulse Testing Solutions

NASA Technical Reports Server (NTRS)

Baffa, Bill

2018-01-01

The Neo test stand is currently configured to fire a horizontally mounted rocket motor with up to 6500 lbf thrust. Currently, the Neo test stand can measure flow of liquid propellant and oxidizer, pressures residing in the closed system up to the combustion chamber. The current configuration does not have the ability to provide all data needed to compute specific impulse. This presents three methods to outfit the NEO test fixture with instrumentation allowing for calculation of specific impulse.

JWST Pathfinder Telescope Risk Reduction Cryo Test Program

NASA Technical Reports Server (NTRS)

Matthews, Gary W.; Scorse, Thomas R.; Spina, John A.; Noel, Darin M.; Havey, Keith A., Jr.; Huguet, Jesse A.; Whitman, Tony L.; Wells, Conrad; Walker, Chanda B.; Lunt, Sharon;

Redesign and Test of an SSME Turbopump for the Large Throat Main Combustion Chamber

NASA Technical Reports Server (NTRS)

Lunde, K. J.; Lee, G. A.; Eastland, A. H.; Rojas, L.

1994-01-01

The preburner oxidizer turbopump for the Space Shuttle Main Engine (SSME) was successfully redesigned for use with the Large Throat Main Combustion Chamber (LTMCC) and tested in air utilizing rapid prototyping. The redesign increases the SSME's operating range with the current Main Combustion Chamber (MCC) while achieving full operational range with the LTMCC. The use of rapid prototyping and air testing to validate the redesign demonstrated the ability to design, fabricate and test designs rapidly and at a very low cost.

Method of infusion extraction

NASA Technical Reports Server (NTRS)

Chang-Diaz, Franklin R. (Inventor)

1989-01-01

Apparatus and method of removing desirable constituents from an infusible material by infusion extraction, where a piston operating in a first chamber draws a solvent into the first chamber where it may be heated, and then moves the heated solvent into a second chamber containing the infusible material, and where infusion extraction takes place. The piston then moves the solvent containing the extract through a filter into the first chamber, leaving the extraction residue in the second chamber.

Chamber B Thermal/Vacuum Chamber: User Test Planning Guide

NASA Technical Reports Server (NTRS)

Montz, Mike E.

2012-01-01

Test process, milestones and inputs are unknowns to first-time users of Chamber B. The User Test Planning Guide aids in establishing expectations for both NASA and non-NASA facility customers. The potential audience for this guide includes both internal and commercial spaceflight hardware/software developers. It is intended to assist their test engineering personnel in test planning and execution. Material covered includes a roadmap of the test process, roles and responsibilities of facility and user, major milestones, facility capabilities, and inputs required by the facility. Samples of deliverables, test article interfaces, and inputs necessary to define test scope, cost, and schedule are included as an appendix to the guide.

Apparatus and method for in-situ cleaning of resist outgassing windows

DOEpatents

Klebanoff, Leonard E.; Haney, Steven J.

2001-01-01

An apparatus and method for in-situ cleaning of resist outgassing windows. The apparatus includes a chamber located in a structure, with the chamber having an outgassing window to be cleaned positioned in alignment with a slot in the chamber, whereby radiation energy passes through the window, the chamber, and the slot onto a resist-coated wafer mounted in the structure. The chamber is connected to a gas supply and the structure is connected to a vacuum pump. Within the chamber are two cylindrical sector electrodes and a filament is electrically connected to one sector electrode and a power supply. In a first cleaning method the sector electrodes are maintained at the same voltage, the filament is unheated, the chamber is filled with argon (Ar) gas under pressure, and the window is maintained at a zero voltage, whereby Ar ions are accelerated onto the window surface, sputtering away carbon deposits that build up as a result of resist outgassing. A second cleaning method is similar except oxygen gas (O.sub.2) is admitted to the chamber instead of Ar. These two methods can be carried out during lithographic operation. A third method, carried out during a maintenance period, involves admitting CO.sub.2 into the chamber, heating the filament to a point of thermionic emission, the sector electrodes are at different voltages, excited CO.sub.2 gas molecules are created which impact the carbon contamination on the window, and gasify it, producing CO gaseous products that are pumped away.

SU-E-T-66: A Prototype for Couch Based Real-Time Dosimetry in External Beam Radiotherapy

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

Ramachandran, P

Purpose: The main purpose of this study is to design a prototype for couch-based based real time dosimetry system in external beam radiotherapy Methods: A prototype of 100 ionization chambers was designed on a printed circuit board by etching the copper layer and each ionization chamber was wired to a 50 pin connector. The signals from the two 50 pin connectors collected from the ionization chambers were then transferred to a PXI module from National Instruments. The PXI module houses a current amplifier that amplifies the charge collected from the ionization chamber. The amplified signal is then sent to amore » digital multimeter module for converting the analog signal to digital signal. A software was designed in labview to read and display the signals obtained from the PXI module. A couch attachment frame was designed to house the 100 ionization chamber module. The frame was fixed underneath the treatment couch for measuring the dose during treatment. Resutls: The ionization chamber based prototype dosimetry was tested for simple radiotherapy treatment fields and found to be a useful device for measuring real time dosimetry at the treatment couch plane. This information could be used to assess the delivered dose to a patient during radiotherapy. It could be used as an invivo dosimeter during radiotherapy. Conclusion: In this study, a prototype for couch based real time dosimetry system was designed and tested. The prototype forms a basis for the development of large scale couch based real time dosimetry system that could be used to perform morning QA prior to treatment, assess real time doses delivered to patient and as a device to monitor the output of the treatment beam. Peter MacCallum Cancer Foundation.« less

Fluctuating disturbances in a Mach 5 wind tunnel

NASA Technical Reports Server (NTRS)

Anders, J. B.; Stainback, P. C.; Beckwith, I. E.; Keefe, L. R.

1976-01-01

An experimental investigation has been conducted to determine the source and nature of disturbances in the settling chamber and test section of a Mach 5 wind tunnel. Various changes in the air supply piping to the wind tunnel are shown to influence the disturbance levels in the settling chamber. These levels were reduced by the use of an acoustic muffler section in the settling chamber. Three nozzles were tested with the same settling chamber and hot-wire measurements indicated that the test section disturbances were entirely acoustic. Significant reductions in the test section noise levels were obtained with an electroplated nozzle utilizing boundary-layer removal upstream of the throat. The source of test section noise is shown to be different for laminar and turbulent nozzle-wall boundary layers.

Validation of a novel epicutaneous delivery system for patch testing of house dust mite-hypersensitive dogs.

PubMed

Olivry, Thierry; Linder, Keith E; Paps, Judy S; Bizikova, Petra; Dunston, Stan; Donne, Nathalie; Mondoulet, Lucie

2012-12-01

Patch tests with allergens are used for the evaluation of cellular hypersensitivity to food and environmental allergens in dogs and humans with atopic dermatitis. Viaskin is a novel allergen epicutaneous delivery system that enhances epidermal allergen capture by immune cells. To compare the use of Viaskin and Finn chamber patch tests in dogs hypersensitive to mite allergens. Empty control or Dermatophagoides farinae house dust mite-containing Viaskin or Finn chamber patches were applied to the thoracic skin of six mite-hypersensitive Maltese-beagle crossbred atopic dogs. Lesions were graded 49 and 72 h after patch test application, and skin biopsies were collected after 72 h. Overall microscopic inflammation, eosinophil and T-lymphocyte infiltrations were scored. Positive macroscopic patch test reactions developed at five of six Viaskin application sites and four of six Finn chamber application sites. Median microscopic epidermal and dermal inflammation, as well as eosinophil and CD3 T-lymphocyte dermal scores were always higher in biopsies collected at Viaskin than at Finn chamber sites. Microscopic inflammation scores were significantly higher after mite allergen-containing Viaskin compared with empty patches, but this was not the case for mite-containing Finn chambers compared with control chambers. Scores obtained using Viaskin were not significantly different from those obtained using Finn chambers. Macroscopic and microscopic scores were significantly correlated. In mite-allergic dogs, Viaskin epicutaneous delivery systems appear to induce stronger allergen-specific inflammation than currently used Finn chamber patch tests. Consequently, Viaskin patches might offer a better alternative for screening cellular hypersensitivity to food and environmental allergens. © 2012 The Authors. Veterinary Dermatology © 2012 ESVD and ACVD.

Engine and method for operating an engine

DOEpatents

Lauper, Jr., John Christian; Willi, Martin Leo [Dunlap, IL; Thirunavukarasu, Balamurugesh [Peoria, IL; Gong, Weidong [Dunlap, IL

2008-12-23

A method of operating an engine is provided. The method may include supplying a combustible combination of reactants to a combustion chamber of the engine, which may include supplying a first hydrocarbon fuel, hydrogen fuel, and a second hydrocarbon fuel to the combustion chamber. Supplying the second hydrocarbon fuel to the combustion chamber may include at least one of supplying at least a portion of the second hydrocarbon fuel from an outlet port that discharges into an intake system of the engine and supplying at least a portion of the second hydrocarbon fuel from an outlet port that discharges into the combustion chamber. Additionally, the method may include combusting the combustible combination of reactants in the combustion chamber.

Comparative release studies on suppositories using the basket, paddle, dialysis tubing and flow-through cell methods I. Acetaminophen in a lipophilic base suppository.

PubMed

Hori, Seiichi; Kawada, Tsubasa; Kogure, Sanae; Yabu, Shinako; Mori, Kenji; Akimoto, Masayuki

2017-02-01

The release characteristics of lipophilic suppositories containing acetaminophen (AAP) were examined using four types of dissolution methods: the basket, paddle, dialysis tubing (DT) and flow-through cell (FTC) methods. The suitability of each apparatus for quality control in AAP compounded suppositories was evaluated using statistical procedures. More than 80% of the drug was released over 60 min in all the release methods studied, with the exception of the basket method. Reproducible and faster release was achieved using the paddle method at 100 and 200 rpm, whereas poor release occurred with the basket method. The mean dissolution time (MDT), maximum dissolved quantity of AAP at the end of the sampling time (Q) and dissolution efficiency (DE) were calculated by model-independent methods. The FTC method with a single chamber used in this study was also appreciable for AAP suppositories (Q of 100%, MDT of 71-91 min and DE of 75-80%). The DT apparatus is considered similar to the FTC apparatus from a quality control perspective for judging the release properties of lipophilic base suppositories containing AAP. However, even the single chamber FTC used in this study has potential as an in vitro drug release test for suppositories. The comparative dissolution method is expected to become one of the valuable tools for selecting an adequate dissolution test.

The Use of the Molecular Adsorber Coating Technology to Mitigate Vacuum Chamber Contamination During Pathfinder Testing for the James Webb Space Telescope

NASA Technical Reports Server (NTRS)

Abraham, Nithin S.; Hasegawa, Mark M.; Wooldridge, Eve M.; Henderson-Nelson, Kelly A.

2016-01-01

As a coating made of highly porous zeolite materials, the Molecular Adsorber Coating (MAC) was developed to capture outgassed molecular contaminants, such as hydrocarbons and silicones. For spaceflight applications, the adsorptive capabilities of the coating can alleviate on-orbit outgassing concerns on or near sensitive surfaces and instruments within the spacecraft. Similarly, this sprayable paint technology has proven to be significantly beneficial for ground based space applications, in particular, for vacuum chamber environments. This paper describes the recent use of the MAC technology during Pathfinder testing of the Optical Ground Support Equipment (OGSE) for the James Webb Space Telescope (JWST) at NASA Johnson Space Center (JSC). The coating was used as a mitigation tool to entrap persistent outgassed contaminants, specifically silicone based diffusion pump oil, from within JSC's cryogenic optical vacuum chamber test facility called Chamber A. This paper summarizes the sample fabrication, installation, laboratory testing, post-test chemical analysis results, and future plans for the MAC technology, which was effectively used to protect the JWST test equipment from vacuum chamber contamination.

The use of the Molecular Adsorber Coating technology to mitigate vacuum chamber contamination during Pathfinder testing for the James Webb Space Telescope

NASA Astrophysics Data System (ADS)

Abraham, Nithin S.; Hasegawa, Mark M.; Wooldridge, Eve M.; Henderson-Nelson, Kelly A.

2016-09-01

As a coating made of highly porous zeolite materials, the Molecular Adsorber Coating (MAC) was developed to capture outgassed molecular contaminants, such as hydrocarbons and silicones. For spaceflight applications, the adsorptive capabilities of the coating can alleviate on-orbit outgassing concerns on or near sensitive surfaces and instruments within the spacecraft. Similarly, this sprayable paint technology has proven to be significantly beneficial for ground based space applications, in particular, for vacuum chamber environments. This paper describes the recent use of the MAC technology during Pathfinder testing of the Optical Ground Support Equipment (OGSE) for the James Webb Space Telescope (JWST) at NASA Johnson Space Center (JSC). The coating was used as a mitigation tool to entrap persistent outgassed contaminants, specifically silicone based diffusion pump oil, from within JSC's cryogenic optical vacuum chamber test facility called Chamber A. This paper summarizes the sample fabrication, installation, laboratory testing, post-test chemical analysis results, and future plans for the MAC technology, which was effectively used to protect the JWST test equipment from vacuum chamber contamination.

Air-kerma strength determination of a new directional {sup 103}Pd source

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

Aima, Manik, E-mail: aima@wisc.edu; Reed, Joshua L.; DeWerd, Larry A.

2015-12-15

Purpose: A new directional {sup 103}Pd planar source array called a CivaSheet™ has been developed by CivaTech Oncology, Inc., for potential use in low-dose-rate (LDR) brachytherapy treatments. The array consists of multiple individual polymer capsules called CivaDots, containing {sup 103}Pd and a gold shield that attenuates the radiation on one side, thus defining a hot and cold side. This novel source requires new methods to establish a source strength metric. The presence of gold material in such close proximity to the active {sup 103}Pd region causes the source spectrum to be significantly different than the energy spectra of seeds normallymore » used in LDR brachytherapy treatments. In this investigation, the authors perform air-kerma strength (S{sub K}) measurements, develop new correction factors for these measurements based on an experimentally verified energy spectrum, and test the robustness of transferring S{sub K} to a well-type ionization chamber. Methods: S{sub K} measurements were performed with the variable-aperture free-air chamber (VAFAC) at the University of Wisconsin Medical Radiation Research Center. Subsequent measurements were then performed in a well-type ionization chamber. To realize the quantity S{sub K} from a directional source with gold material present, new methods and correction factors were considered. Updated correction factors were calculated using the MCNP 6 Monte Carlo code in order to determine S{sub K} with the presence of gold fluorescent energy lines. In addition to S{sub K} measurements, a low-energy high-purity germanium (HPGe) detector was used to experimentally verify the calculated spectrum, a sodium iodide (NaI) scintillating counter was used to verify the azimuthal and polar anisotropy, and a well-type ionization chamber was used to test the feasibility of disseminating S{sub K} values for a directional source within a cylindrically symmetric measurement volume. Results: The UW VAFAC was successfully used to measure the S{sub K} of four CivaDots with reproducibilities within 0.3%. Monte Carlo methods were used to calculate the UW VAFAC correction factors and the calculated spectrum emitted from a CivaDot was experimentally verified with HPGe detector measurements. The well-type ionization chamber showed minimal variation in response (<1.5%) as a function of source positioning angle, indicating that an American Association of Physicists in Medicine (AAPM) Accredited Dosimetry Calibration Laboratory calibrated well chamber would be a suitable device to transfer an S{sub K}-based calibration to a clinical user. S{sub K} per well-chamber ionization current ratios were consistent among the four dots measured. Additionally, the measurements and predictions of anisotropy show uniform emission within the solid angle of the VAFAC, which demonstrates the robustness of the S{sub K} measurement approach. Conclusions: This characterization of a new {sup 103}Pd directional brachytherapy source helps to establish calibration methods that could ultimately be used in the well-established AAPM Task Group 43 formalism. Monte Carlo methods accurately predict the changes in the energy spectrum caused by the fluorescent x-rays produced in the gold shield.« less

Application of Molecular Adsorber Coatings in Chamber A for the James Webb Space Telescope

NASA Technical Reports Server (NTRS)

Abraham, Nithin S.

2017-01-01

As a coating made of highly porous zeolite materials, the Molecular Adsorber Coating (MAC) was developed to capture outgassed molecular contaminants, such as hydrocarbons and silicones. For spaceflight applications, the adsorptive capabilities of the coating can alleviate on-orbit outgassing concerns on or near sensitive surfaces and instruments within the spacecraft. Similarly, this sprayable paint technology has proven to be significantly beneficial for ground-based space applications, in particular, for vacuum chamber environments. This presentation describes the application of the MAC technology for the James Webb Space Telescope (JWST) at NASA Johnson Space Center (JSC). The coating was used as a mitigation tool to entrap outgassed contaminants, specifically silicone-based diffusion pump oil, from within JSCs cryogenic optical vacuum chamber test facility called Chamber A. This presentation summarizes the background, fabrication, installation, chemical analysis test results, and future plans for the MAC technology, which was effectively used to protect the JWST test equipment from vacuum chamber contamination. As a coating made of highly porous zeolite materials, the Molecular Adsorber Coating (MAC) was developed to capture outgassed molecular contaminants, such as hydrocarbons and silicones. For spaceflight applications, the adsorptive capabilities of the coating can alleviate on-orbit outgassing concerns on or near sensitive surfaces and instruments within the spacecraft. Similarly, this sprayable paint technology has proven to be significantly beneficial for ground-based space applications, in particular, for vacuum chamber environments. This presentation describes the application of the MAC technology for the James Webb Space Telescope (JWST) at NASA Johnson Space Center (JSC). The coating was used as a mitigation tool to entrap outgassed contaminants, specifically silicone-based diffusion pump oil, from within JSCs cryogenic optical vacuum chamber test facility called Chamber A. This presentation summarizes the background, fabrication, installation, chemical analysis test results, and future plans for the MAC technology, which was effectively used to protect the JWST test equipment from vacuum chamber contamination.

Tank 12 data dump OME integrated thrust chamber test report, phase 1

NASA Technical Reports Server (NTRS)

Pauckert, R. P.; Tobin, R. D.

1974-01-01

The test program conducted to characterize the steady state stability, thermal, and performance characteristics of the integrated thrust chamber assembly, as well as limited tests to investigate transient characteristics are described.

Installation Restoration General Environmental Technology Development. Task 2. Incineration Test of Explosives Contaminated Soils at Savanna Army Depot Activity, Savanna, Illinois.

DTIC Science & Technology

1984-04-01

800OF and afterburner temperatures below 112000F. Explosives were detected in the combustion gases leaving the primary chamber for one test burn (i.e... combustion chamber. (c) Temperature in the secondary combustion chamber. l These key parameters were selected since they directly re- late to the...4523A 5.4 Heat exchanger (waste heat boiler) . The f lue gases discharged from the secondary combustion chamber were directed, via refractory-lined duct

FDTD simulation of field performance in reverberation chamber excited by two excitation antennas

NASA Astrophysics Data System (ADS)

Wang, Song; Wu, Zhan-cheng; Cui, Yao-zhong

2013-03-01

The excitation source is one of the critical items that determine the electromagnetic fields in a reverberation chamber (RC). In order to optimize the electromagnetic fields performance, a new method of exciting RC with two antennas is proposed based on theoretical analysis. The full 3D simulation of RC is carried out by the finite difference time domain (FDTD) method on two excitation conditions of one antenna and two antennas. The broadband response of RC is obtained by fast Fourier transformation (FFT) after only one simulation. Numerical data show that the field uniformity in the test space is improved on the condition of two transmitting antennas while the normalized electric fields decreased slightly compared to the one antenna condition. It is straightforward to recognize that two antennas excitation can reduce the demands on power amplifier as the total input power is split among the two antennas, and consequently the cost of electromagnetic compatibility (EMC) test in large-scale RC can be reduced.

Design and landing dynamic analysis of reusable landing leg for a near-space manned capsule

NASA Astrophysics Data System (ADS)

Yue, Shuai; Nie, Hong; Zhang, Ming; Wei, Xiaohui; Gan, Shengyong

2018-06-01

To improve the landing performance of a near-space manned capsule under various landing conditions, a novel landing system is designed that employs double chamber and single chamber dampers in the primary and auxiliary struts, respectively. A dynamic model of the landing system is established, and the damper parameters are determined by employing the design method. A single-leg drop test with different initial pitch angles is then conducted to compare and validate the simulation model. Based on the validated simulation model, seven critical landing conditions regarding nine crucial landing responses are found by combining the radial basis function (RBF) surrogate model and adaptive simulated annealing (ASA) optimization method. Subsequently, the adaptability of the landing system under critical landing conditions is analyzed. The results show that the simulation effectively results match the test results, which validates the accuracy of the dynamic model. In addition, all of the crucial responses under their corresponding critical landing conditions satisfy the design specifications, demonstrating the feasibility of the landing system.

Task 12 data dump (phase 2) OME integrated thrust chamber test report

NASA Technical Reports Server (NTRS)

Tobin, R. D.; Pauckert, R. P.

1974-01-01

The characteristics and performance of the orbit maneuvering engine for the space shuttle are discussed. Emphasis is placed on the regeneratively cooled thrust chamber of the engine. Tests were conducted to determine engine operating parameters during the start, shutdown, and restart. Characteristics of the integrated thrust chamber and the performance and thermal conditions for blowdown operation without supplementary boundary layer cooling were investigated. The results of the test program are presented.

Design verification test matrix development for the STME thrust chamber assembly

NASA Technical Reports Server (NTRS)

Dexter, Carol E.; Elam, Sandra K.; Sparks, David L.

1993-01-01

This report presents the results of the test matrix development for design verification at the component level for the National Launch System (NLS) space transportation main engine (STME) thrust chamber assembly (TCA) components including the following: injector, combustion chamber, and nozzle. A systematic approach was used in the development of the minimum recommended TCA matrix resulting in a minimum number of hardware units and a minimum number of hot fire tests.

Evaluation of the smoke density chamber as an apparatus for fire toxicity screening tests

NASA Technical Reports Server (NTRS)

Hilado, C. J.; Labossiere, L. A.

1976-01-01

The smoke density chamber is perhaps the most widely used apparatus for smoke measurements. Because of its availability, it has been proposed as an apparatus for evaluating fire toxicity. The standard apparatus and procedure were not found suitable for toxicity screening tests using laboratory animals, because not enough materials of interest produced animal mortality or even incapacitation under standard test conditions. With modifications, the chamber offers greater promise as a screening tool, but other tests specifically designed to measure relative toxicity may be more cost-effective. Where one-dimensional heat flux is a requirement, the chamber is the most suitable apparatus available. It should be improved in regard to visibility of animals and ease of cleaning.

Apparatus for Testing Flat Specimens of Thermal Insulation

NASA Technical Reports Server (NTRS)

Fesmire, James E.; Augustynowicz, Stanislaw D.

2005-01-01

An apparatus has been developed to implement an improved method of testing flat-plate specimens of thermal-insulation materials for cryogenic application. The method includes testing under realistic use conditions that could include vacuum and mechanical loading at a pressure up to 70 psi (=0.48 MPa). The apparatus can accommodate a rigid or flexible specimen having thickness up to 1.25 in. (=3.2 cm) and diameters between 6 and 10 in. (about 15.2 and 25.4 cm, respectively). Typical test conditions include boundary temperatures between 77 K and 373 K and vacuum/interstitial gas filling at a pressure between 10(exp -6) torr (=1.3 x 10(exp -4) Pa) and 760 torr (atmospheric pressure =0.1 MPa). The interstitial gas could be N2, He, CO2, or any other suitable gas to which the insulation is expected to be exposed in use. Relative to prior apparatuses and testing methods, this apparatus and the testing method that it implements offer advantages of relative simplicity and ease of use. The basic principle of operation of the apparatus is that of boil-off calorimetry, using liquid nitrogen or any other suitable liquid that boils at a desired temperature below ambient temperature. Comparative rates of flow of heat through the thicknesses of the specimens (heat-leak rates) and apparent-thermal-conductivity values are obtained from tests of specimens. Absolute values of heat-leak rates and apparent thermal conductivities are computed from a combination of (1) the aforementioned comparative values and (2) calibration factors obtained by testing reference specimens of materials that have known thermal-insulation properties. The apparatus includes a full complement of temperature sensors, a vacuum pump and chamber, a monitoring and control system, and tools and fixtures that enable rapid and reliable installation and removal of specimens. A specimen is installed at the bottom of the vacuum chamber, and a cold-mass assembly that includes a tank is lowered into position above and around the specimen (see figure). A spring-based compensating fixture helps to ensure adequate thermal contact with possibly irregular specimen surfaces. For a high-compression test, the springs can be replaced with spacers. A flat circular load cell at the bottom of the chamber measures the compressive load on the specimen. Once the desired compressive-load, temperature, and vacuum/gas-filling conditions are established, testing begins. During a test, all measurements are recorded by use of a portable data-acquisition system and a computer. The total heat-leak rate is measured and calculated as the boil-off flow rate multiplied by the latent heat of vaporization. The parasitic heat leak (to the side of the specimen and to the top and side of the cold-mass tank) is reduced to a small fraction of the total heat leak by use of a combination of multilayer-insulation (MLI) shield rings, reflective film, a fiberglass/epoxy centering ring, and a bulk fill of aerogel beads. This combination eliminates the need for a cryogenic guard chamber used in a typical prior apparatus to reduce the parasitic heat leak.

Hot fire test results of subscale tubular combustion chambers

NASA Technical Reports Server (NTRS)

Kazaroff, John M.; Jankovsky, Robert S.; Pavli, Albert J.

1992-01-01

Advanced, subscale, tubular combustion chambers were built and test fired with hydrogen-oxygen propellants to assess the increase in fatigue life that can be obtained with this type of construction. Two chambers were tested: one ran for 637 cycles without failing, compared to a predicted life of 200 cycles for a comparable smooth-wall milled-channel liner configuration. The other chamber failed at 256 cycles, compared to a predicted life of 118 cycles for a comparable smooth-wall milled-channel liner configuration. Posttest metallographic analysis determined that the strain-relieving design (structural compliance) of the tubular configuration was the cause of this increase in life.

Method and apparatus for fabricating a composite structure consisting of a filamentary material in a metal matrix

DOEpatents

Banker, J.G.; Anderson, R.C.

1975-10-21

A method and apparatus are provided for preparing a composite structure consisting of filamentary material within a metal matrix. The method is practiced by the steps of confining the metal for forming the matrix in a first chamber, heating the confined metal to a temperature adequate to effect melting thereof, introducing a stream of inert gas into the chamber for pressurizing the atmosphere in the chamber to a pressure greater than atmospheric pressure, confining the filamentary material in a second chamber, heating the confined filamentary material to a temperature less than the melting temperature of the metal, evacuating the second chamber to provide an atmosphere therein at a pressure, placing the second chamber in registry with the first chamber to provide for the forced flow of the molten metal into the second chamber to effect infiltration of the filamentary material with the molten metal, and thereafter cooling the metal infiltrated-filamentary material to form said composite structure.

A closed-chamber method to measure greenhouse gas fluxes from dry aquatic sediments

NASA Astrophysics Data System (ADS)

Lesmeister, Lukas; Koschorreck, Matthias

2017-06-01

Recent research indicates that greenhouse gas (GHG) emissions from dry aquatic sediments are a relevant process in the freshwater carbon cycle. However, fluxes are difficult to measure because of the often rocky substrate and the dynamic nature of the habitat. Here we tested the performance of different materials to seal a closed chamber to stony ground both in laboratory and field experiments. Using on-site material consistently resulted in elevated fluxes. The artefact was caused both by outgassing of the material and production of gas. The magnitude of the artefact was site dependent - the measured CO2 flux increased between 10 and 208 %. Errors due to incomplete sealing proved to be more severe than errors due to non-inert sealing material.Pottery clay as sealing material provided a tight seal between the chamber and the ground and no production of gases was detected. With this approach it is possible to get reliable gas fluxes from hard-substrate sites without using a permanent collar. Our test experiments confirmed that CO2 fluxes from dry aquatic sediments are similar to CO2 fluxes from terrestrial soils.

Survival and growth of newly transformed Lampsilis cardium and Lampsilis siliquoidea in a flow-through, continuous feeding test system

USGS Publications Warehouse

Meinertz, Jeffery R.; Schreier, Theresa M.; Hess, Karina R.; Bartsch, Michelle

2011-01-01

A test system was evaluated for assessing chronic toxicity of waterborne chemicals with early life stage mussels. To determine if the test system could result in ≥80% survival in a control (unexposed) group, fat mucket mussels (Lampsilis siliquoidea Barnes, 1823) and plain pocketbook mussels (L. cardium Rafinesque, 1820) 1 day post transformation were stocked into test chambers (250 mL beakers, water volume, 200 mL, 21 °C, 40 mussels of 1 species per chamber) within a test system constructed for conducting chronic, continuous exposure, flow-through toxicity tests. The test system contained 60 chambers containing silica sand, 30 chambers with L. siliquoidea, and 30 with L. cardium. Each chamber in the continuous feeding system received 1 of 6 food types prepared with concentrated algal products. After 28 days, mussels were harvested from chambers to assess survival and growth. For L. siliquoidea, mean survival ranged from 34 to 80% and mean shell length ranged from 464 to 643 µm. For L. cardium, mean survival ranged from 12 to 66% and mean shell length ranged from 437 to 612 µm. The maximum mean growth rate for L. siliquoidea was 12.7 µm/d and for L. cardium was 11.8 µm/d. When offered a continuous diet of Nannochloropsis, Tetraselmis, and Chlorella for 28 days in the test system, the survival of 1 day post transformation L. siliquoidea was 80%. The test system can be easily enhanced with a pumping system continuously delivering test chemical to the test system's flow stream allowing for chronic toxicity tests with 1 day post transformation mussels.

Formaldehyde and TVOC emission behavior of laminate flooring by structure of laminate flooring and heating condition.

PubMed

An, Jae-Yoon; Kim, Sumin; Kim, Hyun-Joong

2011-03-15

Formaldehyde was measured with a desiccator, a 20 L chamber and the FLEC method. The formaldehyde emission rate from laminate was the highest at 32 °C using the desiccator, which then decreased with time. The formaldehyde emission using the 20 L small chamber and FLEC showed a similar tendency. There was a strong correlation between the formaldehyde and total volatile organic compounds (TVOCs) with both types of floorings using the two different methods. The formaldehyde emission rate and TVOC results were higher when tested using the FLEC method than with the 20 L small chamber method. The emission rate was affected by the joint edge length in laminate flooring. Toluene, ethylbenzene and xylene were the main VOCs emitted from laminate flooring, and there were more unidentified VOCs emitted than identified VOCs. The samples heated with a floor heating system emitted more formaldehyde than those heated using an air circulation system due to the temperature difference between the bottom panel and flooring. The TVOC emission level of the samples was higher when an air circulation system was used than when a floor heating system was used due to the high ventilation rate. Copyright © 2010 Elsevier B.V. All rights reserved.

40 CFR 797.1930 - Mysid shrimp acute toxicity test.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 31 2010-07-01 2010-07-01 true Mysid shrimp acute toxicity test. 797... acclimated in accordance with the test design into the test chambers. Mysids in the test chambers are... individuals are of similar age and experimental history. Mysids used for establishing laboratory cultures may...

Liquid Engine Design: Effect of Chamber Dimensions on Specific Impulse

NASA Technical Reports Server (NTRS)

Hoggard, Lindsay; Leahy, Joe

2009-01-01

Which assumption of combustion chemistry - frozen or equilibrium - should be used in the prediction of liquid rocket engine performance calculations? Can a correlation be developed for this? A literature search using the LaSSe tool, an online repository of old rocket data and reports, was completed. Test results of NTO/Aerozine-50 and Lox/LH2 subscale and full-scale injector and combustion chamber test results were found and studied for this task. NASA code, Chemical Equilibrium with Applications (CEA) was used to predict engine performance using both chemistry assumptions, defined here. Frozen- composition remains frozen during expansion through the nozzle. Equilibrium- instantaneous chemical equilibrium during nozzle expansion. Chamber parameters were varied to understand what dimensions drive chamber C* and Isp. Contraction Ratio is the ratio of the nozzle throat area to the area of the chamber. L is the length of the chamber. Characteristic chamber length, L*, is the length that the chamber would be if it were a straight tube and had no converging nozzle. Goal: Develop a qualitative and quantitative correlation for performance parameters - Specific Impulse (Isp) and Characteristic Velocity (C*) - as a function of one or more chamber dimensions - Contraction Ratio (CR), Chamber Length (L ) and/or Characteristic Chamber Length (L*). Determine if chamber dimensions can be correlated to frozen or equilibrium chemistry.

Performance of a transpiration-regenerative cooled rocket thrust chamber

NASA Technical Reports Server (NTRS)

Valler, H. W.

1979-01-01

The analysis, design, fabrication, and testing of a liquid rocket engine thrust chamber which is gas transpiration cooled in the high heat flux convergent portion of the chamber and water jacket cooled (simulated regenerative) in the barrel and divergent sections of the chamber are described. The engine burns LOX-hydrogen propellants at a chamber pressure of 600 psia. Various transpiration coolant flow rates were tested with resultant local hot gas wall temperatures in the 800 F to 1400 F range. The feasibility of transpiration cooling with hydrogen and helium, and the use of photo-etched copper platelets for heat transfer and coolant metering was successfully demonstrated.

Automatic stage identification of Drosophila egg chamber based on DAPI images

PubMed Central

Jia, Dongyu; Xu, Qiuping; Xie, Qian; Mio, Washington; Deng, Wu-Min

2016-01-01

The Drosophila egg chamber, whose development is divided into 14 stages, is a well-established model for developmental biology. However, visual stage determination can be a tedious, subjective and time-consuming task prone to errors. Our study presents an objective, reliable and repeatable automated method for quantifying cell features and classifying egg chamber stages based on DAPI images. The proposed approach is composed of two steps: 1) a feature extraction step and 2) a statistical modeling step. The egg chamber features used are egg chamber size, oocyte size, egg chamber ratio and distribution of follicle cells. Methods for determining the on-site of the polytene stage and centripetal migration are also discussed. The statistical model uses linear and ordinal regression to explore the stage-feature relationships and classify egg chamber stages. Combined with machine learning, our method has great potential to enable discovery of hidden developmental mechanisms. PMID:26732176

Method of plasma etching Ga-based compound semiconductors

DOEpatents

Qiu, Weibin; Goddard, Lynford L.

2012-12-25

A method of plasma etching Ga-based compound semiconductors includes providing a process chamber and a source electrode adjacent to the process chamber. The process chamber contains a sample comprising a Ga-based compound semiconductor. The sample is in contact with a platen which is electrically connected to a first power supply, and the source electrode is electrically connected to a second power supply. The method includes flowing SiCl.sub.4 gas into the chamber, flowing Ar gas into the chamber, and flowing H.sub.2 gas into the chamber. RF power is supplied independently to the source electrode and the platen. A plasma is generated based on the gases in the process chamber, and regions of a surface of the sample adjacent to one or more masked portions of the surface are etched to create a substantially smooth etched surface including features having substantially vertical walls beneath the masked portions.

Dual-Chamber/Dual-Anode Proportional Counter Incorporating an Intervening Thin-Foil Solid Neutron Converter

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

Boatner, Lynn A; Neal, John S; Blackston, Matthew A

2012-01-01

A dual-chamber/dual-anode gas proportional counter utilizing thin solid 6LiF or 10B neutron converters coated on a 2-micon-thick Mylar film that is positioned between the two counter chambers and anodes has been designed, fabricated, and tested using a variety of fill gases including naturally abundant helium. In this device, neutron conversion products emitted from both sides of the coated converter foil are detected rather than having half of the products absorbed in the wall of a conventional tube type counter where the solid neutron converter is deposited on the tube wall. Geant4-based radiation transport calculations were used to determine the optimummore » neutron converter coating thickness for both isotopes. Solution methods for applying these optimized-thickness coatings on a Mylar film were developed that were carried out at room temperature without any specialized equipment and that can be adapted to standard coating methods such as silk screen or ink jet printing. The performance characteristics of the dual-chamber/dual-anode neutron detector were determined for both types of isotopically enriched converters. The experimental performance of the 6LiF converter-based detector was described well by modeling results from Geant4. Additional modeling studies of multiple-foil/multiple-chamber/anode configurations addressed the basic issue of the relatively longer absorption range of neutrons versus the shorter range of the conversion products for 6LiF and 10B. Combined with the experimental results, these simulations indicate that a high-performance neutron detector can be realized in a single device through the application of these multiple-foil/solid converter, multiple-chamber detector concepts.« less

Method and apparatus for incinerating hazardous waste

DOEpatents

Korenberg, Jacob

1990-01-01

An incineration apparatus and method for disposal of infectious hazardous waste including a fluidized bed reactor containing a bed of granular material. The reactor includes a first chamber, a second chamber, and a vertical partition separating the first and second chambers. A pressurized stream of air is supplied to the reactor at a sufficient velocity to fluidize the granular material in both the first and second chambers. Waste materials to be incinerated are fed into the first chamber of the fluidized bed, the fine waste materials being initially incinerated in the first chamber and subsequently circulated over the partition to the second chamber wherein further incineration occurs. Coarse waste materials are removed from the first chamber, comminuted, and recirculated to the second chamber for further incineration. Any partially incinerated waste materials and ash from the bottom of the second chamber are removed and recirculated to the second chamber for further incineration. This process is repeated until all infectious hazardous waste has been completely incinerated.

An Evaluation of the Additional Acoustic Power Needed to Overcome the Effects of a Test-Articles Absorption During Reverberant Chamber Acoustic Testing of Spaceflight Hardware

NASA Technical Reports Server (NTRS)

Hozman, Aron D.; Hughes, William O.

2014-01-01

It is important to realize that some test-articles may have significant sound absorption that may challenge the acoustic power capabilities of a test facility. Therefore, to mitigate this risk of not being able to meet the customers target spectrum, it is prudent to demonstrate early-on an increased acoustic power capability which compensates for this test-article absorption. This paper describes a concise method to reduce this risk when testing aerospace test-articles which have significant absorption. This method was successfully applied during the SpaceX Falcon 9 Payload Fairing acoustic test program at the NASA Glenn Research Center Plum Brook Stations RATF.

Design and testing of a model CELSS chamber robot

NASA Astrophysics Data System (ADS)

Davis, Mark; Dezego, Shawn; Jones, Kinzy; Kewley, Christopher; Langlais, Mike; McCarthy, John; Penny, Damon; Bonner, Tom; Funderburke, C. Ashley; Hailey, Ruth

1994-08-01

A robot system for use in an enclosed environment was designed and tested. The conceptual design will be used to assist in research performed by the Controlled Ecological Life Support System (CELSS) project. Design specifications include maximum load capacity, operation at specified environmental conditions, low maintenance, and safety. The robot system must not be hazardous to the sealed environment, and be capable of stowing and deploying within a minimum area of the CELSS chamber facility. This design consists of a telescoping robot arm that slides vertically on a shaft positioned in the center of the CELSS chamber. The telescoping robot arm consists of a series of links which can be fully extended to a length equal to the radius of the working envelope of the CELSS chamber. The vertical motion of the robot arm is achieved through the use of a combination ball screw/ball spline actuator system. The robot arm rotates cylindrically about the vertical axis through use of a turntable bearing attached to a central mounting structure fitted to the actuator shaft. The shaft is installed in an overhead rail system allowing the entire structure to be stowed and deployed within the CELSS chamber. The overhead rail system is located above the chamber's upper lamps and extends to the center of the CELSS chamber. The mounting interface of the actuator shaft and rail system allows the entire actuator shaft to be detached and removed from the CELSS chamber. When the actuator shaft is deployed, it is held fixed at the bottom of the chamber by placing a square knob on the bottom of the shaft into a recessed square fitting in the bottom of the chamber floor. A support boot ensures the rigidity of the shaft. Three student teams combined into one group designed a model of the CELSS chamber robot that they could build. They investigated materials, availability, and strength in their design. After the model arm and stand were built, the class performed pre-tests on the entire system. A stability pre-test was used to determine whether the model robot arm would tip over on the stand when it was fully extended. Results showed the stand tipped when 50 Newtons were applied horizontally to the top of the vertical shaft while the arm was fully extended.

Design and testing of a model CELSS chamber robot

NASA Technical Reports Server (NTRS)

Davis, Mark; Dezego, Shawn; Jones, Kinzy; Kewley, Christopher; Langlais, Mike; Mccarthy, John; Penny, Damon; Bonner, Tom; Funderburke, C. Ashley; Hailey, Ruth

1994-01-01

A robot system for use in an enclosed environment was designed and tested. The conceptual design will be used to assist in research performed by the Controlled Ecological Life Support System (CELSS) project. Design specifications include maximum load capacity, operation at specified environmental conditions, low maintenance, and safety. The robot system must not be hazardous to the sealed environment, and be capable of stowing and deploying within a minimum area of the CELSS chamber facility. This design consists of a telescoping robot arm that slides vertically on a shaft positioned in the center of the CELSS chamber. The telescoping robot arm consists of a series of links which can be fully extended to a length equal to the radius of the working envelope of the CELSS chamber. The vertical motion of the robot arm is achieved through the use of a combination ball screw/ball spline actuator system. The robot arm rotates cylindrically about the vertical axis through use of a turntable bearing attached to a central mounting structure fitted to the actuator shaft. The shaft is installed in an overhead rail system allowing the entire structure to be stowed and deployed within the CELSS chamber. The overhead rail system is located above the chamber's upper lamps and extends to the center of the CELSS chamber. The mounting interface of the actuator shaft and rail system allows the entire actuator shaft to be detached and removed from the CELSS chamber. When the actuator shaft is deployed, it is held fixed at the bottom of the chamber by placing a square knob on the bottom of the shaft into a recessed square fitting in the bottom of the chamber floor. A support boot ensures the rigidity of the shaft. Three student teams combined into one group designed a model of the CELSS chamber robot that they could build. They investigated materials, availability, and strength in their design. After the model arm and stand were built, the class performed pre-tests on the entire system. A stability pre-test was used to determine whether the model robot arm would tip over on the stand when it was fully extended. Results showed the stand tipped when 50 Newtons were applied horizontally to the top of the vertical shaft while the arm was fully extended. This proved that it was stable. Another pre-test was the actuator slip test used to determine if there is an adequate coefficient of friction between the actuator drive wheels and drive cable to enable the actuator to fully extend and retract the arm. This pre-test revealed that the coefficient of friction was not large enough to prevent slippage. Sandpaper was glued to the drive wheel and this eliminated the slippage problem. The class preformed a fit test in the CELSS chamber to ensure that the completed robot arm is capable of reaching the entire working envelope. The robot was centered in the chamber and the arm was fully extended to the sides of the chamber. The arm was also able to retract to clear the drain pipes separating the upper and lower plant trays.

Solder Joint Health Monitoring Testbed

NASA Technical Reports Server (NTRS)

Delaney, Michael M.; Flynn, James; Browder, Mark

2009-01-01

A method of monitoring the health of selected solder joints, called SJ-BIST, has been developed by Ridgetop Group Inc. under a Small Business Innovative Research (SBIR) contract. The primary goal of this research program is to test and validate this method in a flight environment using realistically seeded faults in selected solder joints. An additional objective is to gather environmental data for future development of physics-based and data-driven prognostics algorithms. A test board is being designed using a Xilinx FPGA. These boards will be tested both in flight and on the ground using a shaker table and an altitude chamber.

EMI / EMC Design for Class D Payloads (Resource Prospector / NIRVSS)

NASA Technical Reports Server (NTRS)

Forgione, Josh; Benton, Joshua Eric; Thompson, Sarah; Colaprete, Anthony

2015-01-01

EMI/EMC techniques are applied to a Class D instrument (NIRVSS) to achieve low noise performance and reduce risk of EMI/EMC testing failures and/or issues during system integration and test. Basic techniques are not terribly expensive or complex, but do require close coordination between electrical and mechanical staff early in the design process. Low-cost methods to test subsystems on the bench without renting an EMI chamber are discussed. This method was applied to the NIRVSS instrument and achieved improvements up to 59dB on conducted emissions measurements between hardware revisions.

[Acoustic Levitation Methods and Apparatus

NASA Technical Reports Server (NTRS)

Barmatz, M. B.; Jacobi, N. (Inventor)

1982-01-01

Methods are described for acoustically levitating objects within chambers of spherical and cylindrical shape. The wavelengths for chambers of particular dimensions are given, for generating standing wave patterns of any of a variety of modes within the chambers. For a spherical chamber the lowest resonant mode is excited by applying a wavelength of 3.02R, where R is the chamber radius. The two lowest pure radial modes for that chamber, are excited by applying wavelengths of 1.40R and 0.814R. For a cylindrical chamber of radius R, the lowest mode is at a wavelength of 3.41R, and the lowest pure radial modes are at wavelengths of 1.64R and 0.896R.

David Florida Laboratory: Support for mobile satellite communications

NASA Technical Reports Server (NTRS)

Dumoulin, Jean-Guy; Mamen, Rolf

1995-01-01

The comprehensive integration and environmental (including RF) test facilities of the Canadian Space Agency's David Florida Laboratory (CSA)(DFL) were used extensively for the MSAT Program. Following a description of the facilities, the paper outlines their application to the qualification of the two MSAT satellites following an overview of the test plan. Particular emphasis is given to passive intermodulation measurement (PIM) demands, which for the MSAT satellites, contributed to the need to extend the anechoic chamber. The extended chamber was also used for an EMC test and SAR signature test of the RADARSAT satellite. The DFL's facilities are being used for additional aspects of mobile satellite communications. One shielded anechoic Extra High Frequency (EHF) chamber and associated test equipment are employed predominantly for measuring the performance of the IRIDIUM satellites' Engineering Model Gateway Moveable Antennas (EM)(GMA). Other chambers are used for testing aeronautical antennas on behalf of Inmarsat. Still others combine thermal and PIM testing. The paper concludes with a review of the test requirements of evolving satcom missions such as Inmarsat Aero-1.

Method for lowering the VOCS emitted during drying of wood products

DOEpatents

Banerjee, Sujit; Boerner, James Robert; Su, Wei

2000-01-01

The present invention is directed to a method for removal of VOCs from wood products prior to drying the wood products. The method of the invention includes the steps of providing a chamber having an opening for receiving wood and loading the chamber with green wood. The wood is loaded to an extent sufficient to provide a limited headspace in the chamber. The chamber is then closed and the wood is heated in the chamber for a time and at a temperature sufficient to saturate the headspace with moisture and to substantially transfer VOCs from the wood product to the moisture in the headspace.

Research on structural design and test technologies for a three-chamber launching device

NASA Astrophysics Data System (ADS)

Jun, Wu; Qiushi, Yan; Ling, Xiao; Tieshuan, Zhuang; Chengyu, Yang

2016-07-01

A three-chamber launching device with improved acceleration is proposed and developed. As indicated by the damage generated during the pill and engineering protection tests, the proposed device is applicable as a high-speed launching platform for pills of different shapes and quality levels. Specifically, it can be used to investigate kinetic energy weapons and their highly destructive effects due to the resulting large bomb fragments. In the horizontal direction of the barrel, two auxiliary chambers are set at a certain distance from the main chamber. When the pill reaches the mouth of the auxiliary chambers, the charges in the auxiliary chambers are ignited by the high-temperature, high-pressure combustible gas trailing the pill. The combustible gas in the auxiliary chambers can resist the rear pressure of the pill and thus maintain the high pressure of the pill base. In this way, the required secondary acceleration of the pill is met. The proposed device features the advantage of launching a pill with high initial velocity under low bore pressure. Key techniques are proposed in the design of the device to address the problems related to the angle between the main chamber axis and the ancillary chamber axis, the overall design of a three-chamber barrel, the structural design of auxiliary propellant charge, the high-pressure combustible gas sealing technology, and the sabot and belt design. Results from the launching test verify the reasonable design of this device and its reliable structural sealing. Additionally, the stiffness and the strength of the barrel meet design requirements. Compared with the single-chamber launching device with the same caliber, the proposed device increases the average launching velocity by approximately 15% and the amount of muzzle kinetic energy by approximately 35%. Therefore, this equipment is capable of carrying out small-caliber, high-speed pill firing tests.

Infusion extractor

NASA Technical Reports Server (NTRS)

Chang-Diaz, Franklin R. (Inventor)

1986-01-01

This invention relates to an apparatus and method of removing desirable constituents from an infusible material by infusion extraction. A piston operating in a first chamber draws a solvent into the first chamber where it may be heated, and then moves the heated solvent into a second chamber containing the infusible material, where infusion extraction takes place. The piston then moves the solvent containing the extract through a filter into the first chamber, leaving the extraction residue in the second chamber. The method is applicable to operation in low or micro-gravity environments.

Ensuring a reliable satellite

NASA Astrophysics Data System (ADS)

Johnson, Charles E.; Persinger, Randy R.; Lemon, James J.; Volkert, Keith J.

Comprehensive testing and monitoring approaches have been formulated and implemented for Intelsat VI, which is the largest commercial satellite in service. An account is given of the ground test program from unit level through launch site activities, giving attention to the test data handling system. Test methods unique to Intelsat VI encompass near-field anechoic chamber antenna measurements, offloading 1-g deployment of solar cell and deflector antennas, and electrostatic discharge measurements. The problems accruing to the sheer size of this spacecraft are stressed.

A Sensitive Cloud Chamber without Radioactive Sources

ERIC Educational Resources Information Center

Zeze, Syoji; Itoh, Akio; Oyama, Ayu; Takahashi, Haruka

2012-01-01

We present a sensitive diffusion cloud chamber which does not require any radioactive sources. A major difference from commonly used chambers is the use of a heat sink as its bottom plate. The result of a performance test of the chamber is given. (Contains 8 figures.)

Performance of Several Combustion Chambers Designed for Aircraft Oil Engines

NASA Technical Reports Server (NTRS)

Joachim, William F; Kemper, Carlton

1928-01-01

Several investigations have been made on single-cylinder test engines to determine the performance characteristics of four types of combustion chambers designed for aircraft oil engines. Two of the combustion chambers studied were bulb-type precombustion chambers, the connecting orifice of one having been designed to produce high turbulence by tangential air flow in both the precombustion chamber and the cylinder. The other two were integral combustion chambers, one being dome-shaped and the other pent-roof shaped. The injection systems used included cam and eccentric driven fuel pumps, and diaphragm and spring-loaded fuel-injection valves. A diaphragm type maximum cylinder pressure indicator was used in part of these investigations with which the cylinder pressures were controlled to definite valves. The performance of the engines when equipped with each of the combustion chambers is discussed. The best performance for the tests reported was obtained with a bulb-type combustion chamber designed to give a high degree of turbulence within the bulb and cylinder. (author)

A Combined Hazard Index Fire Test Methodology for Aircraft Cabin Materials. Volume II.

DTIC Science & Technology

1982-04-01

Technical Center. The report was divided into two parts: Part I described the improved technology investigated to upgrade existin methods for testing...proper implementation of the computerized data acquisition and reduction programs will improve materials hazards measurement precision. Thus, other...the hold chamber before and after injection of a sample, will improve precision and repeatability of measurement. The listed data acquisition and

Method and apparatus for filling thermal insulating systems

DOEpatents

Arasteh, Dariush K.

1992-01-01

A method for filling insulated glazing units is disclosed. The method utilizes a vacuum chamber in which the insulated glazing units are placed. The insulated glazing units and vacuum chamber are evacuated simultaneously. The units are then refilled with a low conductance gas such as Krypton while the chamber is simultaneously refilled with air.

SU-E-T-109: Development of An End-To-End Test for the Varian TrueBeamtm with a Novel Multiple-Dosimetric Modality H and N Phantom

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

Zakjevskii, V; Knill, C; Rakowski, J

2014-06-01

Purpose: To develop a comprehensive end-to-end test for Varian's TrueBeam linear accelerator for head and neck IMRT using a custom phantom designed to utilize multiple dosimetry devices. Methods: The initial end-to-end test and custom H and N phantom were designed to yield maximum information in anatomical regions significant to H and N plans with respect to: i) geometric accuracy, ii) dosimetric accuracy, and iii) treatment reproducibility. The phantom was designed in collaboration with Integrated Medical Technologies. A CT image was taken with a 1mm slice thickness. The CT was imported into Varian's Eclipse treatment planning system, where OARs and themore » PTV were contoured. A clinical template was used to create an eight field static gantry angle IMRT plan. After optimization, dose was calculated using the Analytic Anisotropic Algorithm with inhomogeneity correction. Plans were delivered with a TrueBeam equipped with a high definition MLC. Preliminary end-to-end results were measured using film and ion chambers. Ion chamber dose measurements were compared to the TPS. Films were analyzed with FilmQAPro using composite gamma index. Results: Film analysis for the initial end-to-end plan with a geometrically simple PTV showed average gamma pass rates >99% with a passing criterion of 3% / 3mm. Film analysis of a plan with a more realistic, ie. complex, PTV yielded pass rates >99% in clinically important regions containing the PTV, spinal cord and parotid glands. Ion chamber measurements were on average within 1.21% of calculated dose for both plans. Conclusion: trials have demonstrated that our end-to-end testing methods provide baseline values for the dosimetric and geometric accuracy of Varian's TrueBeam system.« less

Amygdala activity associated with social choice in mice.

PubMed

Mihara, Takuma; Mensah-Brown, Kobina; Sobota, Rosanna; Lin, Robert; Featherstone, Robert; Siegel, Steven J

2017-08-14

Studies suggest that the amygdala is a key region for regulation of anxiety, fear and social function. Therefore, dysfunction of the amygdala has been proposed as a potential mechanism for negative symptoms in schizophrenia. This may be due to NMDA receptor-mediated hypofunction, which is thought to be related to the pathogenesis of schizophrenia. In this study, electroencephalographic amygdala activity was assessed in mice during the three-chamber social test. This activity was also evaluated following exposure to the NMDA receptor antagonist ketamine. Vehicle-treated mice spent significantly more time in the social than the non-social chamber. This social preference was eliminated by ketamine. However, ketamine-treated mice spent significantly less time in the social chamber and significantly more time in the nonsocial chamber than vehicle-treated mice. There were no significant differences in induced powers between social and non-social chamber entries in vehicle-treated mice, except for theta frequencies, which featured greater induced theta power during non-social chamber entry. Ketamine eliminated differences in induced theta power between social and non-social chamber entries. Moreover, ketamine increased the induced gamma power during social chamber entry compared to that of vehicle-treated mice. All other frequency ranges were not significantly influenced by zone or drug condition. All significant findings were upon entry to chambers not during interaction. Results suggest that impaired function of NMDA receptor-mediated glutamate transmission can induce social impairments and amygdala dysfunction, similar to the pattern in schizophrenia. Future studies will utilize this method to evaluate mechanisms of social dysfunction and development of treatments of social impairments in schizophrenia. Copyright © 2017. Published by Elsevier B.V.

Radio frequency plasma method for uniform surface processing of RF cavities and other three-dimensional structures

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

Popovic, Svetozar; Upadhyay, Janardan; Vuskovic, Leposava

2017-12-26

A method for efficient plasma etching of surfaces inside three-dimensional structures can include positioning an inner electrode within the chamber cavity; evacuating the chamber cavity; adding a first inert gas to the chamber cavity; regulating the pressure in the chamber; generating a plasma sheath along the inner wall of the chamber cavity; adjusting a positive D.C. bias on the inner electrode to establish an effective plasma sheath voltage; adding a first electronegative gas to the chamber cavity; optionally readjusting the positive D.C. bias on the inner electrode reestablish the effective plasma sheath voltage at the chamber cavity; etching the innermore » wall of the chamber cavity; and polishing the inner wall to a desired surface roughness.« less

The ribbon-cutting ceremony unveils the reactivated altitude chamber inside the O&C high bay

NASA Technical Reports Server (NTRS)

1999-01-01

At a ribbon-cutting ceremony inside the Operations and Checkout Building high bay, Sterling Walker, director of Engineering Development, introduces the project team members responsible for renovating an altitude chamber formerly used on the Apollo program. In addition, management, media and onlookers are present for the ceremony. Seated in the front row left are (left to right) Terry Smith, director of Engineering, Boeing Space Coast Operations; Steve Francois, director, Space Station and Shuttle Payloads; Jay Greene, International Space Station manager for Technical; and Roy Bridges, center director. The chamber was reactivated, after a 24-year hiatus, to perform leak tests on International Space Station pressurized modules at the launch site. Originally, two chambers were built to test the Apollo command and lunar service modules. They were last used in 1975 during the Apollo-Soyuz Test Project. After installation of new vacuum pumping equipment and controls, a new control room, and a new rotation handling fixture, the chamber again became operational in February 1999. The chamber, which is 33 feet in diameter and 50 feet tall, is constructed of stainless steel. The first module that will be tested for leaks is the U.S. Laboratory. No date has been determined for the test.

In-line Microwave Warmer for Blood and Intravenous Fluids.

DTIC Science & Technology

1989-12-14

circuit was designed and tested. This circuit uses a digitally controlled optically coupled Triac , a thyristor device, which acts as a switch to allow...three sites of the circuit : Inlet Port of Heating Chamber Interior Path of Heating Chamber Outlet Port of Heating Chamber 4) Feedback Control Mechanism...accomplished through use of a closed loop test circuit depicted in Figure 1-2. This test circuit can be used to heat iv fluids or blood on a continuous

Laboratory study of PCBs transport from primary sources to ...

EPA Pesticide Factsheets

The sorption of airborne polychlorinated biphenyls (PCBs) by twenty building materials and their subsequent re-emission (desorption) from concrete were investigated using two 53-L environmental chambers connected in series with a field-collected caulk in the source chamber serving as a stable source of PCBs and building materials in the test chamber. During the tests, the PCB concentrations in the outlet air of the test chamber were monitored and the building materials were removed from the test chamber at different times to determine their PCB content. Among the materials tested, a petroleum-based paint, a latex paint, and a certain type of carpet were among the strongest sinks. Solvent-free epoxy coating, certain types of flooring materials, and brick were among the weakest sinks. For a given sink material, PCB congeners with lower vapor pressures were sorbed in larger quantities. Rough estimates of the partition and diffusion coefficients were obtained by applying a sink model to the data acquired from the chamber studies. A desorption test with the concrete panels showed that re-emission is a slow process, suggesting that PCB sinks, e.g. concrete, can release PCBs into the air for a prolonged period of time (years or decades). This study could fill some of the data gaps associated with the characterization of PCB sinks in contaminated buildings. This paper summarizes the laboratory research results for PCB transport from primary sources to PCB sinks, includ

Verification of International Space Station Component Leak Rates by Helium Accumulation Method

NASA Technical Reports Server (NTRS)

Underwood, Steve D.; Smith, Sherry L.

2003-01-01

Discovery of leakage on several International Space Station U.S. Laboratory Module ammonia system quick disconnects (QDs) led to the need for a process to quantify total leakage without removing the QDs from the system. An innovative solution was proposed allowing quantitative leak rate measurement at ambient external pressure without QD removal. The method utilizes a helium mass spectrometer configured in the detector probe mode to determine helium leak rates inside a containment hood installed on the test component. The method was validated through extensive developmental testing. Test results showed the method was viable, accurate and repeatable for a wide range of leak rates. The accumulation method has been accepted by NASA and is currently being used by Boeing Huntsville, Boeing Kennedy Space Center and Boeing Johnson Space Center to test welds and valves and will be used by Alenia to test the Cupola. The method has been used in place of more expensive vacuum chamber testing which requires removing the test component from the system.

Electromagnetic Compatibility Testing Studies

NASA Technical Reports Server (NTRS)

Trost, Thomas F.; Mitra, Atindra K.

1996-01-01

This report discusses the results on analytical models and measurement and simulation of statistical properties from a study of microwave reverberation (mode-stirred) chambers performed at Texas Tech University. Two analytical models of power transfer vs. frequency in a chamber, one for antenna-to-antenna transfer and the other for antenna to D-dot sensor, were experimentally validated in our chamber. Two examples are presented of the measurement and calculation of chamber Q, one for each of the models. Measurements of EM power density validate a theoretical probability distribution on and away from the chamber walls and also yield a distribution with larger standard deviation at frequencies below the range of validity of the theory. Measurements of EM power density at pairs of points which validate a theoretical spatial correlation function on the chamber walls and also yield a correlation function with larger correlation length, R(sub corr), at frequencies below the range of validity of the theory. A numerical simulation, employing a rectangular cavity with a moving wall shows agreement with the measurements. The determination that the lowest frequency at which the theoretical spatial correlation function is valid in our chamber is considerably higher than the lowest frequency recommended by current guidelines for utilizing reverberation chambers in EMC testing. Two suggestions have been made for future studies related to EMC testing.

Cryogenic Testing of the Thermal Vacuum Chamber and Ground Support Equipment for the James Webb Space Telescope in Chamber A at Johnson Space Center

NASA Technical Reports Server (NTRS)

DiPirro, M.; Homan, J.; Havey, K.; Ousley, W.

2017-01-01

The James Webb Space Telescope (JWST) is the largest cryogenic instrument telescope to be developed for space flight. The telescope will be passively cooled to 50 K and the instrument package will be at 40 K with the mid-infrared instrument at 6 K. The final cryogenic test of the Optical Telescope Element (OTE) and Integrated Science Instrument Module (ISIM) as an assembly (OTE + ISIM OTIS) will be performed in the largest 15 K chamber in the world, Chamber A at Johnson Space Center. The planned duration of this test will be 100 days in the middle of 2017. Needless to say, this ultimate test of OTIS, the cryogenic portion of JWST will be crucial in verifying the end-to-end performance of JWST. A repeat of this test would not only be expensive, but would delay the launch schedule (currently October 2018). Therefore a series of checkouts and verifications of the chamber and ground support equipment were planned and carried out between 2012 and 2016. This paper will provide a top-level summary of those tests, trades in coming up with the test plan, as well as some details of individual issues that were encountered and resolved in the course of testing.

Liquid rocket engine self-cooled combustion chambers

NASA Technical Reports Server (NTRS)

1977-01-01

Self-cooled combustion chambers are chambers in which the chamber wall temperature is controlled by methods other than fluid flow within the chamber wall supplied from an external source. In such chambers, adiabatic wall temperature may be controlled by use of upstream fluid components such as the injector or a film-coolant ring, or by internal flow of self-contained materials; e.g. pyrolysis gas flow in charring ablators, and the flow of infiltrated liquid metals in porous matrices. Five types of self-cooled chambers are considered in this monograph. The name identifying the chamber is indicative of the method (mechanism) by which the chamber is cooled, as follows: ablative; radiation cooled; internally regenerative (Interegen); heat sink; adiabatic wall. Except for the Interegen and heat sink concepts, each chamber type is discussed separately. A separate and final section of the monograph deals with heat transfer to the chamber wall and treats Stanton number evaluation, film cooling, and film-coolant injection techniques, since these subjects are common to all chamber types. Techniques for analysis of gas film cooling and liquid film cooling are presented.

KSC-99pp0237

NASA Image and Video Library

1999-02-25

KENNEDY SPACE CENTER, FLA. -- Cutting a red ribbon for the unveiling of a newly renovated altitude chamber are (left to right) Tommy Mack, project manager, NASA; Steve Francois, director, Space Station and Shuttle Payloads; Sterling Walker, director, Engineering Development; Roy Bridges, director, Kennedy Space Center; Jay Greene, International Space Station manager for Technical; Michael Terry, project manager, Boeing; and Terry Smith, director of Engineering, Boeing Space Coast Operations. The chamber was reactivated, after a 24-year hiatus, to perform leak tests on International Space Station pressurized modules at the launch site. Originally, two chambers were built to test the Apollo command and lunar service modules. They were last used in 1975 during the Apollo-Soyuz Test Project. After installation of new vacuum pumping equipment and controls, a new control room, and a new rotation handling fixture, the chamber again became operational in February 1999. The chamber, which is 33 feet in diameter and 50 feet tall, is constructed of stainless steel. The first module that will be tested for leaks is the U.S. Laboratory. No date has been determined for the test

LARGE SCALE REFRIGERATION PLANT FOR GROUND TESTING THE JAMES WEBB TELESCOPE AT NASA JOHNSON SPACE CENTER

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

P. Arnold, Lutz Decker, D. Howe, J. Urbin, Jonathan Homan, Carl Reis, J. Creel, V. Ganni, P. Knudsen, A. Sidi-Yekhlef

The James Webb Telescope is the successor to the Hubble Telescope and will be placed in an orbit of 1.5 million km from earth. Before launch in 2014, the telescope will be tested in NASA Johnson Space Center's (JSC) space simulation chamber, Chamber A. The tests will be conducted at deep space conditions. Chamber A's helium cryo-panels are currently cooled down to 20 K by two Linde 3.5 kW helium refrigerators. The new 12.5 kW, 20-K helium coldbox described in this paper is part of the upgrade to the chamber systems for this large test program. The Linde coldbox willmore » provide refrigeration in several operating modes where the temperature of the chamber is being controlled with a high accuracy due to the demanding NASA test requirements. The implementation of two parallel expansion turbine strings and the Ganni cycle—Floating Pressure process results in a highly efficient and flexible process that minimizes the electrical input power. This paper will describe the collaboration and execution of the coldbox project.« less

Signal Processing Methods for Liquid Rocket Engine Combustion Stability Assessments

NASA Technical Reports Server (NTRS)

Kenny, R. Jeremy; Lee, Erik; Hulka, James R.; Casiano, Matthew

2011-01-01

The J2X Gas Generator engine design specifications include dynamic, spontaneous, and broadband combustion stability requirements. These requirements are verified empirically based high frequency chamber pressure measurements and analyses. Dynamic stability is determined with the dynamic pressure response due to an artificial perturbation of the combustion chamber pressure (bomb testing), and spontaneous and broadband stability are determined from the dynamic pressure responses during steady operation starting at specified power levels. J2X Workhorse Gas Generator testing included bomb tests with multiple hardware configurations and operating conditions, including a configuration used explicitly for engine verification test series. This work covers signal processing techniques developed at Marshall Space Flight Center (MSFC) to help assess engine design stability requirements. Dynamic stability assessments were performed following both the CPIA 655 guidelines and a MSFC in-house developed statistical-based approach. The statistical approach was developed to better verify when the dynamic pressure amplitudes corresponding to a particular frequency returned back to pre-bomb characteristics. This was accomplished by first determining the statistical characteristics of the pre-bomb dynamic levels. The pre-bomb statistical characterization provided 95% coverage bounds; these bounds were used as a quantitative measure to determine when the post-bomb signal returned to pre-bomb conditions. The time for post-bomb levels to acceptably return to pre-bomb levels was compared to the dominant frequency-dependent time recommended by CPIA 655. Results for multiple test configurations, including stable and unstable configurations, were reviewed. Spontaneous stability was assessed using two processes: 1) characterization of the ratio of the peak response amplitudes to the excited chamber acoustic mode amplitudes and 2) characterization of the variability of the peak response's frequency over the test duration. This characterization process assists in evaluating the discreteness of a signal as well as the stability of the chamber response. Broadband stability was assessed using a running root-mean-square evaluation. These techniques were also employed, in a comparative analysis, on available Fastrac data, and these results are presented here.

Using dynamic flux chambers to estimate the natural attenuation rates in the subsurface at petroleum contaminated sites.

PubMed

Verginelli, Iason; Pecoraro, Roberto; Baciocchi, Renato

2018-04-01

In this work, we introduce a screening method for the evaluation of the natural attenuation rates in the subsurface at sites contaminated by petroleum hydrocarbons. The method is based on the combination of the data obtained from standard source characterization with dynamic flux chambers measurements. The natural attenuation rates are calculated as difference between the flux of contaminants estimated with a non-reactive diffusive model starting from the concentrations of the contaminants detected in the source (soil and/or groundwater) and the effective emission rate of the contaminants measured using dynamic flux chambers installed at ground level. The reliability of this approach was tested in a contaminated site characterized by the presence of BTEX in soil and groundwater. Namely, the BTEX emission rates from the subsurface were measured in 4 seasonal campaigns using dynamic flux chambers installed in 14 sampling points. The comparison of measured fluxes with those predicted using a non-reactive diffusive model, starting from the source concentrations, showed that, in line with other recent studies, the modelling approach can overestimate the expected outdoor concentration of petroleum hydrocarbons even up to 4 orders of magnitude. On the other hand, by coupling the measured data with the fluxes estimated with the diffusive non-reactive model, it was possible to perform a mass balance to evaluate the natural attenuation loss rates of petroleum hydrocarbons during the migration from the source to ground level. Based on this comparison, the estimated BTEX loss rates in the test site were up to almost 0.5kg/year/m 2 . These rates are in line with the values reported in the recent literature for natural source zone depletion. In short, the method presented in this work can represent an easy-to-use and cost-effective option that can provide a further line of evidence of natural attenuation rates expected at contaminated sites. Copyright © 2017 Elsevier B.V. All rights reserved.

Methodology for the in vitro evaluation of the delivery efficiency from valved holding chambers with facemasks.

PubMed

Xu, Zhen; Hsu, Wenchi; von Hollen, Dirk; Viswanath, Ashwin; Nikander, Kurt; Dalby, Richard

2014-08-01

In vitro performance studies of valved holding chamber (VHC)-facemask systems are a cost-effective means of circumventing potentially confounding clinical variables. This article reports results of an in vitro investigation into VHC-facemask performance, using three age-specific soft anatomical model (SAM) faces, under clinically relevant conditions. A potentially standardized method was developed to assess VHC-facemask seal leakage, and evaluate the in vitro delivery efficiency of conventional and antistatic VHC-facemask systems. A custom-built test rig and VHC cradles were used to position the VHC-facemask systems against the SAM faces, with a constant, reproducible force. A standardized simulated pediatric breathing pattern (tidal volume = 155 mL; inhalation:exhalation ratio = 40:60; 25 breaths/min) was utilized. Percent facemask seal leakage, percent delivered dose, and the effect of different numbers of simulated breaths (2 to 8) were investigated. Of the VHC-facemask systems tested, the OptiChamber Diamond VHC with LiteTouch facemask (Diamond) system had the lowest percent seal leakage with each SAM face. Percent seal leakage from the other VHC-facemask systems was similar with SAM0 and SAM2 faces; the AeroChamber Plus Z-Stat VHC with ComfortSeal facemask (AC Z-Stat) system had a substantially greater percent seal leakage with the SAM1 face. Regardless of the number of simulated breaths, the Diamond system delivered the greatest mean percent delivered dose, with the lowest coefficient of variation, with each SAM face. Percent delivered dose did not correlate well with seal leakage, particularly for VHC-facemask systems with high seal leakage. The electrostatic properties of the VHCs appeared to influence drug delivery. This study describes a potentially standardized method for the evaluation of VHC-facemask systems. Use of this method enabled a comprehensive investigation into the influence of clinically relevant variables, including age-specific facial anatomy, number of simulated breaths, and seal leakage, on the delivery efficiency of several commercially available VHC-facemask systems.

Blast from pressurized carbon dioxide released into a vented atmospheric chamber

NASA Astrophysics Data System (ADS)

Hansen, P. M.; Gaathaug, A. V.; Bjerketvedt, D.; Vaagsaether, K.

2018-03-01

This study describes the blast from pressurized carbon dioxide (CO2) released from a high-pressure reservoir into an openly vented atmospheric chamber. Small-scale experiments with pure vapor and liquid/vapor mixtures were conducted and compared with simulations. A motivation was to investigate the effects of vent size and liquid content on the peak overpressure and impulse response in the atmospheric chamber. The comparison of vapor-phase CO2 test results with simulations showed good agreement. This numerical code described single-phase gas dynamics inside a closed chamber, but did not model any phase transitions. Hence, the simulations described a vapor-only test into an unvented chamber. Nevertheless, the simulations reproduced the incident shock wave, the shock reflections, and the jet release inside the atmospheric chamber. The rapid phase transition did not contribute to the initial shock strength in the current test geometry. The evaporation rate was too low to contribute to the measured peak overpressure that was in the range of 15-20 kPa. The simulation results produced a calculated peak overpressure of 12 kPa. The liquid tests showed a significantly higher impulse compared to tests with pure vapor. Reducing the vent opening from 0.1 to 0.01 m2 resulted in a slightly higher impulse calculated at 100 ms. The influence of the vent area on the calculated impulse was significant in the vapor-phase tests, but not so clear in the liquid/vapor mixture tests.

Continuous flow, explosives vapor generator and sensor chamber.

PubMed

Collins, Greg E; Giordano, Braden C; Sivaprakasam, Vasanthi; Ananth, Ramagopal; Hammond, Mark; Merritt, Charles D; Tucker, John E; Malito, Michael; Eversole, Jay D; Rose-Pehrsson, Susan

2014-05-01

A novel liquid injection vapor generator (LIVG) is demonstrated that is amenable to low vapor pressure explosives, 2,4,6-trinitrotoluene and hexahydro-1,3,5-trinitro-1,3,5-triazine. The LIVG operates in a continuous manner, providing a constant and stable vapor output over a period of days and whose concentration can be extended over as much as three orders of magnitude. In addition, a large test atmosphere chamber attached to the LIVG is described, which enables the generation of a stable test atmosphere with controllable humidity and temperature. The size of the chamber allows for the complete insertion of testing instruments or arrays of materials into a uniform test atmosphere, and various electrical feedthroughs, insertion ports, and sealed doors permit simple and effective access to the sample chamber and its vapor.

40 CFR 797.1950 - Mysid shrimp chronic toxicity test.

Code of Federal Regulations, 2010 CFR

2010-07-01

... kill 50 percent of a test population during continuous exposure over a specified period of time. (6... with the test design into retention chambers within the test and the control chambers. Mysids in the... the definitive test. (ii) The mysids should be exposed to a series of widely spaced concentrations of...

16 CFR 1631.4 - Test procedure.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 16 Commercial Practices 2 2012-01-01 2012-01-01 false Test procedure. 1631.4 Section 1631.4... SURFACE FLAMMABILITY OF SMALL CARPETS AND RUGS (FF 2-70) The Standard § 1631.4 Test procedure. (a) Apparatus—(1) Test chamber. The test chamber shall consist of an open top hollow cube made of noncombustible...

16 CFR 1630.4 - Test procedure.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 16 Commercial Practices 2 2012-01-01 2012-01-01 false Test procedure. 1630.4 Section 1630.4... SURFACE FLAMMABILITY OF CARPETS AND RUGS (FF 1-70) The Standard § 1630.4 Test procedure. (a) Apparatus—(1) Test chamber. The test chamber shall consist of an open top hollow cube made of noncombustible material...

16 CFR 1615.4 - Test procedure.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 16 Commercial Practices 2 2014-01-01 2014-01-01 false Test procedure. 1615.4 Section 1615.4... FLAMMABILITY OF CHILDREN'S SLEEPWEAR: SIZES 0 THROUGH 6X (FF 3-71) The Standard § 1615.4 Test procedure. (a) Apparatus—(1) Test chamber. The test chamber shall be a steel cabinet with inside dimensions of 32.9 cm...

40 CFR 53.65 - Test procedure: Loading test.

Code of Federal Regulations, 2013 CFR

2013-07-01

... performing the test in § 53.62 (full wind tunnel test), § 53.63 (wind tunnel inlet aspiration test), or § 53... particle delivery system shall consist of a static chamber or a low velocity wind tunnel having a.... The mean velocity in the test section of the static chamber or wind tunnel shall not exceed 2 km/hr...

Effect of flame-tube head structure on combustion chamber performance

NASA Technical Reports Server (NTRS)

Gu, Minqqi

1986-01-01

The experimental combustion performance of a premixed, pilot-type flame tube with various head structures is discussed. The test study covers an extensive area: efficiency of the combustion chamber, quality of the outlet temperature field, limit of the fuel-lean blowout, ignition performance at ground starting, and carbon deposition. As a result of these tests, a nozzle was found which fits the premixed pilot flame tube well. The use of this nozzle optimized the performance of the combustion chamber. The tested models had premixed pilot chambers with two types of air-film-cooling structures, six types of venturi-tube structures, and secondary fuel nozzles with two small spray-cone angles.

Collection of quantitative chemical release field data.

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

Demirgian, J.; Macha, S.; Loyola Univ.

1999-01-01

Detection and quantitation of chemicals in the environment requires Fourier-transform infrared (FTIR) instruments that are properly calibrated and tested. This calibration and testing requires field testing using matrices that are representative of actual instrument use conditions. Three methods commonly used for developing calibration files and training sets in the field are a closed optical cell or chamber, a large-scale chemical release, and a small-scale chemical release. There is no best method. The advantages and limitations of each method should be considered in evaluating field results. Proper calibration characterizes the sensitivity of an instrument, its ability to detect a component inmore » different matrices, and the quantitative accuracy and precision of the results.« less

To Create Space on Earth: The Space Environment Simulation Laboratory and Project Apollo

NASA Technical Reports Server (NTRS)

Walters, Lori C.

2003-01-01

Few undertakings in the history of humanity can compare to the great technological achievement known as Project Apollo. Among those who witnessed Armstrong#s flickering television image were thousands of people who had directly contributed to this historic moment. Amongst those in this vast anonymous cadre were the personnel of the Space Environment Simulation Laboratory (SESL) at the Manned Spacecraft Center (MSC) in Houston, Texas. SESL houses two large thermal-vacuum chambers with solar simulation capabilities. At a time when NASA engineers had a limited understanding of the effects of extremes of space on hardware and crews, SESL was designed to literally create the conditions of space on Earth. With interior dimensions of 90 feet in height and a 55-foot diameter, Chamber A dwarfed the Apollo command/service module (CSM) it was constructed to test. The chamber#s vacuum pumping capacity of 1 x 10(exp -6) torr can simulate an altitude greater than 130 miles above the Earth. A "lunar plane" capable of rotating a 150,000-pound test vehicle 180 deg replicates the revolution of a craft in space. To reproduce the temperature extremes of space, interior chamber walls cool to -280F as two banks of carbon arc modules simulate the unfiltered solar light/heat of the Sun. With capabilities similar to that of Chamber A, early Chamber B tests included the Gemini modular maneuvering unit, Apollo EVA mobility unit and the lunar module. Since Gemini astronaut Charles Bassett first ventured into the chamber in 1966, Chamber B has assisted astronauts in testing hardware and preparing them for work in the harsh extremes of space.

Outbred CD1 mice are as suitable as inbred C57BL/6J mice in performing social tasks.

PubMed

Hsieh, Lawrence S; Wen, John H; Miyares, Laura; Lombroso, Paul J; Bordey, Angélique

2017-01-10

Inbred mouse strains have been used preferentially for behavioral testing over outbred counterparts, even though outbred mice reflect the genetic diversity in the human population better. Here, we compare the sociability of widely available outbred CD1 mice with the commonly used inbred C57BL/6J (C57) mice in the one-chamber social interaction test and the three-chamber sociability test. In the one-chamber task, intra-strain pairs of juvenile, non-littermate, male CD1 or C57 mice display a series of social and aggressive behaviors. While CD1 and C57 pairs spend equal amount of time socializing, CD1 pairs spend significantly more time engaged in aggressive behaviors than C57 mice. In the three-chamber task, sociability of C57 mice was less dependent on acclimation paradigms than CD1 mice. Following acclimation to all three chambers, both groups of age-matched male mice spent more time in the chamber containing a stranger mouse than in the empty chamber, suggesting that CD1 mice are sociable like C57 mice. However, the observed power suggests that it is easier to achieve statistical significance with C57 than CD1 mice. Because the stranger mouse could be considered as a novel object, we assessed for a novelty effect by adding an object. CD1 mice spend more time in the chamber with a stranger mouse than that a novel object, suggesting that their preference is social in nature. Thus, outbred CD1 mice are as appropriate as inbred C57 mice for studying social behavior using either the single or the three-chamber test using a specific acclimation paradigm. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Development and Hotfire Testing of Additively Manufactured Copper Combustion Chambers for Liquid Rocket Engine Applications

NASA Technical Reports Server (NTRS)

Gradl, Paul R.; Greene, Sandy; Protz, Chris

2017-01-01

NASA and industry partners are working towards fabrication process development to reduce costs and schedules associated with manufacturing liquid rocket engine components with the goal of reducing overall mission costs. One such technique being evaluated is powder-bed fusion or selective laser melting (SLM), commonly referred to as additive manufacturing (AM). The NASA Low Cost Upper Stage Propulsion (LCUSP) program was designed to develop processes and material characterization for GRCop-84 (a NASA Glenn Research Center-developed copper, chrome, niobium alloy) commensurate with powder bed AM, evaluate bimetallic deposition, and complete testing of a full scale combustion chamber. As part of this development, the process has been transferred to industry partners to enable a long-term supply chain of monolithic copper combustion chambers. To advance the processes further and allow for optimization with multiple materials, NASA is also investigating the feasibility of bimetallic AM chambers. In addition to the LCUSP program, NASA’s Marshall Space Flight Center (MSFC) has completed a series of development programs and hot-fire tests to demonstrate SLM GRCop-84 and other AM techniques. MSFC’s efforts include a 4,000 pounds-force thrust liquid oxygen/methane (LOX/CH4) combustion chamber. Small thrust chambers for 1,200 pounds-force LOX/hydrogen (H2) applications have also been designed and fabricated with SLM GRCop-84. Similar chambers have also completed development with an Inconel 625 jacket bonded to the GRCop-84 material, evaluating direct metal deposition (DMD) laser- and arc-based techniques. The same technologies for these lower thrust applications are being applied to 25,000-35,000 pounds-force main combustion chamber (MCC) designs. This paper describes the design, development, manufacturing and testing of these numerous combustion chambers, and the associated lessons learned throughout their design and development processes.

Peltier-based cloud chamber

NASA Astrophysics Data System (ADS)

Nar, Sevda Yeliz; Cakir, Altan

2018-02-01

Particles produced by nuclear decay, cosmic radiation and reactions can be identified through various methods. One of these methods that has been effective in the last century is the cloud chamber. The chamber makes visible cosmic particles that we are exposed to radiation per second. Diffusion cloud chamber is a kind of cloud chamber that is cooled by dry ice. This traditional model has some application difficulties. In this work, Peltier-based cloud chamber cooled by thermoelectric modules is studied. The new model provided uniformly cooled base of the chamber, moreover, it has longer lifetime than the traditional chamber in terms of observation time. This gain has reduced the costs which spent each time for cosmic particle observation. The chamber is an easy-to-use system according to traditional diffusion cloud chamber. The new model is portable, easier to make, and can be used in the nuclear physics experiments. In addition, it would be very useful to observe Muons which are the direct evidence for Lorentz contraction and time expansion predicted by Einsteins special relativity principle.

Method for separating the non-inked cellulose fibers from the inked cellulose fibers in cellulosic materials

DOEpatents

Woodward, Jonathan

1998-01-01

A method for enzymatically separating the non-inked cellulose fibers from the inked cellulose fibers in cellulosic materials. The cellulosic material, such as newsprint, is introduced into a first chamber containing a plastic canvas basket. This first chamber is in fluid communication, via plastic tubing, with a second chamber containing cellobiase beads in a plastic canvas basket. Cellulase is then introduced into the first chamber. A programmable pump then controls the flow rate between the two chambers. The action of cellulase and stirring in the first chamber results in the production of a slurry of newsprint pulp in the first chamber. This slurry contains non-inked fibers, inked fibers, and some cellobiose. The inked fibers and cellobiose flow from the first chamber to the second chamber, whereas the non-inked fibers remain in the first chamber because they are too large to pass through the pores of the plastic canvas basket. The resulting non-inked and inked fibers are then recovered.

Method for separating the non-inked cellulose fibers from the inked cellulose fibers in cellulosic materials

DOEpatents

Woodward, J.

1998-12-01

A method for enzymatically separating the non-inked cellulose fibers from the inked cellulose fibers in cellulosic materials. The cellulosic material, such as newsprint, is introduced into a first chamber containing a plastic canvas basket. This first chamber is in fluid communication, via plastic tubing, with a second chamber containing cellobiase beads in a plastic canvas basket. Cellulase is then introduced into the first chamber. A programmable pump then controls the flow rate between the two chambers. The action of cellulase and stirring in the first chamber results in the production of a slurry of newsprint pulp in the first chamber. This slurry contains non-inked fibers, inked fibers, and some cellobiose. The inked fibers and cellobiose flow from the first chamber to the second chamber, whereas the non-inked fibers remain in the first chamber because they are too large to pass through the pores of the plastic canvas basket. The resulting non-inked and inked fibers are then recovered. 6 figs.

Method and apparatus for filling thermal insulating systems

DOEpatents

Arasteh, D.K.

1992-01-14

A method for filling insulated glazing units is disclosed. The method utilizes a vacuum chamber in which the insulated glazing units are placed. The insulated glazing units and vacuum chamber are evacuated simultaneously. The units are then refilled with a low conductance gas such as Krypton while the chamber is simultaneously refilled with air. 3 figs.

Method and apparatus for extracting water from air using a desiccant

DOEpatents

Spletzer, Barry L.; Callow, Diane Schafer

2003-01-01

The present invention provides a method and apparatus for extracting liquid water from moist air using minimal energy input. The method can be considered as four phases: (1) adsorbing water from air into a desiccant, (2) isolating the water-laden desiccant from the air source, (3) desorbing water as vapor from the desiccant into a chamber, and (4) isolating the desiccant from the chamber, and compressing the vapor in the chamber to form liquid condensate. The liquid condensate can be removed for use. Careful design of the dead volumes and pressure balances can minimize the energy required. The dried air can be exchanged for fresh moist air and the process repeated. An apparatus comprises a first chamber in fluid communication with a desiccant, and having ports to intake moist air and exhaust dried air. The apparatus also comprises a second chamber in fluid communication with the desiccant. The second chamber allows variable internal pressure, and has a port for removal of liquid condensate. Each chamber can be configured to be isolated or in communication with the desiccant. The first chamber can be configured to be isolated or in communication with a course of moist air. Various arrangements of valves, pistons, and chambers are described.

Image quality, meteorological optical range, and fog particulate number evaluation using the Sandia National Laboratories fog chamber

DOE PAGES

Birch, Gabriel C.; Woo, Bryana L.; Sanchez, Andres L.; ...

2017-08-24

The evaluation of optical system performance in fog conditions typically requires field testing. This can be challenging due to the unpredictable nature of fog generation and the temporal and spatial nonuniformity of the phenomenon itself. We describe the Sandia National Laboratories fog chamber, a new test facility that enables the repeatable generation of fog within a 55 m×3 m×3 m (L×W×H) environment, and demonstrate the fog chamber through a series of optical tests. These tests are performed to evaluate system image quality, determine meteorological optical range (MOR), and measure the number of particles in the atmosphere. Relationships between typical opticalmore » quality metrics, MOR values, and total number of fog particles are described using the data obtained from the fog chamber and repeated over a series of three tests.« less

Image quality, meteorological optical range, and fog particulate number evaluation using the Sandia National Laboratories fog chamber

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

Birch, Gabriel C.; Woo, Bryana L.; Sanchez, Andres L.

The evaluation of optical system performance in fog conditions typically requires field testing. This can be challenging due to the unpredictable nature of fog generation and the temporal and spatial nonuniformity of the phenomenon itself. We describe the Sandia National Laboratories fog chamber, a new test facility that enables the repeatable generation of fog within a 55 m×3 m×3 m (L×W×H) environment, and demonstrate the fog chamber through a series of optical tests. These tests are performed to evaluate system image quality, determine meteorological optical range (MOR), and measure the number of particles in the atmosphere. Relationships between typical opticalmore » quality metrics, MOR values, and total number of fog particles are described using the data obtained from the fog chamber and repeated over a series of three tests.« less

Comparison of immersion ultrasound, partial coherence interferometry, and low coherence reflectometry for ocular biometry in cataract patients.

PubMed

Montés-Micó, Robert; Carones, Francesco; Buttacchio, Antonietta; Ferrer-Blasco, Teresa; Madrid-Costa, David

2011-09-01

To compare ocular biometry parameters measured with immersion ultrasound, partial coherence interferometry, and low coherence reflectometry in cataract patients. Measurements of axial length and anterior chamber depth were analyzed and compared using immersion ultrasound, partial coherence interferometry, and low coherence reflectometry. Keratometry (K), flattest axis, and white-to-white measurements were compared between partial coherence interferometry and low coherence reflectometry. Seventy-eight cataract (LOCS II range: 1 to 3) eyes of 45 patients aged between 42 and 90 years were evaluated. A subanalysis as a function of cataract degree was done for axial length and anterior chamber depth between techniques. No statistically significant differences were noted for the study cohort or within each cataract degree among the three techniques for axial length and anterior chamber depth (P>.05, ANOVA test). Measurements between techniques were highly correlated for axial length (R=0.99) and anterior chamber depth (R=0.90 to 0.96) for all methods. Keratometry, flattest axis, and white-to-white measurements were comparable (paired t test, P>.1) and correlated well between partial coherence interferometry and low coherence reflectometry (K1 [R=0.95), K2 [R=0.97], flattest axis [R=0.95], and white-to-white [R=0.92]). Immersion ultrasound, partial coherence interferometry, and low coherence reflectometry provided comparable ocular biometry measurements in cataractous eyes. Copyright 2011, SLACK Incorporated.

Biomimetic Unidirectional Capillary Action

NASA Astrophysics Data System (ADS)

Rupert, Eric; Moran, Patrick; Dahl, Jason

2017-11-01

In arid environments animals require specialized adaptations to collect adequate water. The Texas horned lizard (P. cornutum) has superhydrophylic skin which draws water out of moist soil or directly from water sources. The water then makes its way into the lizard's unidirectional capillary system, made of overlapping scales, which serves to channel water to its mouth. Testing different channel geometries, repeated ``D'' shaped chambers as in Commans et al. (2015) and truncated isosceles triangle chambers, as found in P. cornutum, we show the ability to have passive, unidirectional, fluid transport. Tests were carried out with the capillaries in a horizontal configuration. While both capillary geometries produced the desired traits, the triangular chambers showed superior unidirectionality, with no observed back flow, while ``D'' chambers showed back flow under testing conditions. The chambers provided similar flow rates. These types of channel systems will find use in microfluidics, notably in medical, printing, and lab-on-chip applications.

Independent testing of the Fisher & Paykel Healthcare MR860 Laparoscopic Humidification System.

PubMed

Sammour, Tarik; Kahokehr, Arman; Hill, Andrew G

2010-08-01

In laparoscopic surgery CO2 is commonly insufflated at room temperature, with a relative humidity approaching 0%. There has been an increase in utilization of devices to warm and humidify the insufflated gas to avoid potential detrimental effects caused by desiccation. Available data on the performance of these devices are limited. We aimed to conduct independent testing of the Fisher & Paykel MR860 Laparoscopic Humidification System at variable flow rates. A 2.5l insulated chamber was constructed and a digital thermo-hygrometer placed inside it. The humidifier water vessel was weighed and exactly 30.0g of water poured in. 50.0L of CO2 was insufflated into the chamber via the humidifier at 2.0L/min, 4.0l/min, 6.0l/min, 8.0l/min, and 10l/min using a laparoscopic insufflator. Measurements of temperature and humidity in the chamber were taken at 30 second intervals. After 50.0l of gas was insufflated the water left in the humidifier was weighed, and this was used to calculate the mean absolute humidity of the insufflated gas by the gravimetric method. At every flow rate, > 98.0% relative humidity was achieved in the chamber after less than 30 seconds of insufflation. Using the gravimetric estimate, the humidifier was able to saturate 50.0l of CO2 to close to saturation humidity at every flow rate tested. The Fisher & Paykel MR860 Laparoscopic Humidification System effectively humidifies insufflated CO2 at a range of flow rates commonly used in the surgical setting.

Novel approach to study the cardiovascular effects and mechanism of action of urban particulate matter using lung epithelial-endothelial tetra-culture system.

PubMed

Kim, Ha Ryong; Cho, Han Soo; Shin, Da Young; Chung, Kyu Hyuck

2017-02-01

In vitro models have become increasingly sophisticated, and their usefulness in supporting toxicity testing is well established. The present study was designed to establish a novel in vitro model that mimics the cellular network surrounding airways and pulmonary blood vessels, to study the cardiovascular toxic effects of particulate matter (PM). Transwell culture method was used to develop a novel tetra-culture system consisting of tri-cultures (one lung epithelial and two immune cell lines) in the apical chamber and endothelial cells in the basolateral chamber. Tri-cultures were exposed to standard reference material (SRM) 1648a, an urban PM. SRM 1648a did not show cytotoxic effects; however, it increased IL-6 level in apical and basolateral chambers. The cells in the basolateral chamber showed increased monocyte adhesion. Furthermore, exposure of tri-cultured cells to SRM 1648a in the apical chamber induced ICAM-1 expression in endothelial cells in the basolateral chamber by activating the IL-6/STAT3 pathway. In conclusion, a tetra-culture system was established to facilitate the identification of cellular adhesion molecule expression induced by the interaction between pulmonary epithelial and endothelial cells. The tetra-culture system will contribute to elucidation of the relationships between inhalable PM and cardiovascular diseases. Copyright © 2016 Elsevier Ltd. All rights reserved.

In Vitro Culturing and Live Imaging of Drosophila Egg Chambers: A History and Adaptable Method.

PubMed

Peters, Nathaniel C; Berg, Celeste A

2016-01-01

The development of the Drosophila egg chamber encompasses a myriad of diverse germline and somatic events, and as such, the egg chamber has become a widely used and influential developmental model. Advantages of this system include physical accessibility, genetic tractability, and amenability to microscopy and live culturing, the last of which is the focus of this chapter. To provide adequate context, we summarize the structure of the Drosophila ovary and egg chamber, the morphogenetic events of oogenesis, the history of egg-chamber live culturing, and many of the important discoveries that this culturing has afforded. Subsequently, we discuss various culturing methods that have facilitated analyses of different stages of egg-chamber development and different types of cells within the egg chamber, and we present an optimized protocol for live culturing Drosophila egg chambers.We designed this protocol for culturing late-stage Drosophila egg chambers and live imaging epithelial tube morphogenesis, but with appropriate modifications, it can be used to culture egg chambers of any stage. The protocol employs a liquid-permeable, weighted "blanket" to gently hold egg chambers against the coverslip in a glass-bottomed culture dish so the egg chambers can be imaged on an inverted microscope. This setup provides a more buffered, stable, culturing environment than previously published methods by using a larger volume of culture media, but the setup is also compatible with small volumes. This chapter should aid researchers in their efforts to culture and live-image Drosophila egg chambers, further augmenting the impressive power of this model system.

In vitro culturing and live imaging of Drosophila egg chambers: A history and adaptable method

PubMed Central

Peters, Nathaniel C.; Berg, Celeste A.

2017-01-01

Summary/Abstract The development of the Drosophila egg chamber encompasses a myriad of diverse germline and somatic events, and as such, the egg chamber has become a widely used and influential developmental model. Advantages of this system include physical accessibility, genetic tractability, and amenability to microscopy and live culturing, the last of which is the focus of this chapter. To provide adequate context, we summarize the structure of the Drosophila ovary and egg chamber, the morphogenetic events of oogenesis, the history of egg-chamber live culturing, and many of the important discoveries that this culturing has afforded. Subsequently, we discuss various culturing methods that have facilitated analyses of different stages of egg-chamber development and different types of cells within the egg chamber, and we present an optimized protocol for live culturing Drosophila egg chambers. We designed this protocol for culturing late-stage Drosophila egg chambers and live imaging epithelial tube morphogenesis, but with appropriate modifications it can be used to culture egg chambers of any stage. The protocol employs a liquid-permeable, weighted, “blanket” to gently hold egg chambers against the coverslip in a glass-bottomed culture dish so the egg chambers can be imaged on an inverted microscope. This setup provides a more buffered, stable culturing environment than previously published methods by using a larger volume of culture media, but the setup is also compatible with small volumes. This chapter should aid researchers in their efforts to culture and live image Drosophila egg chambers, further augmenting the impressive power of this model system. PMID:27557572

Fluorine compounds for doping conductive oxide thin films

DOEpatents

Gessert, Tim; Li, Xiaonan; Barnes, Teresa M; Torres, Jr., Robert; Wyse, Carrie L

2013-04-23

Methods of forming a conductive fluorine-doped metal oxide layer on a substrate by chemical vapor deposition are described. The methods may include heating the substrate in a processing chamber, and introducing a metal-containing precursor and a fluorine-containing precursor to the processing chamber. The methods may also include adding an oxygen-containing precursor to the processing chamber. The precursors are reacted to deposit the fluorine-doped metal oxide layer on the substrate. Methods may also include forming the conductive fluorine-doped metal oxide layer by plasma-assisted chemical vapor deposition. These methods may include providing the substrate in a processing chamber, and introducing a metal-containing precursor, and a fluorine-containing precursor to the processing chamber. A plasma may be formed that includes species from the metal-containing precursor and the fluorine-containing precursor. The species may react to deposit the fluorine-doped metal oxide layer on the substrate.

Technical Capability Upgrades to the NASA Langley Research Center 8 ft. by 15 ft. Thermal Vacuum Chamber

NASA Technical Reports Server (NTRS)

Thornblom, Mark N.; Beverly, Joshua; O'Connell, Joseph J.; Duncan, Dwight L.

2016-01-01

The 8 ft. by 15 ft. thermal vacuum chamber (TVAC), housed in Building 1250 at the NASA Langley Research Center (LaRC), and managed by the Systems Integration and Test Branch within the Engineering Directorate, has undergone several significant modifications to increase testing capability, safety, and quality of measurements of articles under environmental test. Significant modifications include: a new nitrogen distribution manifold for supplying the shroud and other cold surfaces to liquid nitrogen temperatures; a new power supply and distribution system for accurately controlling a quartz IR lamp suite; a suite of contamination monitoring sensors for outgassing measurements and species identification; a new test article support system; signal and power feed-throughs; elimination of unnecessary penetrations; and a new data acquisition and control commanding system including safety interlocks. This paper will provide a general overview of the LaRC 8 ft. by 15 ft. TVAC chamber, an overview of the new technical capabilities, and will illustrate each upgrade in detail, in terms of mechanical design and predicted performance. Additionally, an overview of the scope of tests currently being performed in the chamber will be documented, and sensor plots from tests will be provided to show chamber temperature and pressure performance with actual flight hardware under test.

Low emissions compression ignited engine technology

DOEpatents

Coleman, Gerald N [Dunlap, IL; Kilkenny, Jonathan P [Peoria, IL; Fluga, Eric C [Dunlap, IL; Duffy, Kevin P [East Peoria, IL

2007-04-03

A method and apparatus for operating a compression ignition engine having a cylinder wall, a piston, and a head defining a combustion chamber. The method and apparatus includes delivering fuel substantially uniformly into the combustion chamber, the fuel being dispersed throughout the combustion chamber and spaced from the cylinder wall, delivering an oxidant into the combustion chamber sufficient to support combustion at a first predetermined combustion duration, and delivering a diluent into the combustion chamber sufficient to change the first predetermined combustion duration to a second predetermined combustion duration different from the first predetermined combustion duration.

Contamination Control Assessment of the World's Largest Space Environment Simulation Chamber

NASA Technical Reports Server (NTRS)

Snyder, Aaron; Henry, Michael W.; Grisnik, Stanley P.; Sinclair, Stephen M.

2012-01-01

The Space Power Facility s thermal vacuum test chamber is the largest chamber in the world capable of providing an environment for space simulation. To improve performance and meet stringent requirements of a wide customer base, significant modifications were made to the vacuum chamber. These include major changes to the vacuum system and numerous enhancements to the chamber s unique polar crane, with a goal of providing high cleanliness levels. The significance of these changes and modifications are discussed in this paper. In addition, the composition and arrangement of the pumping system and its impact on molecular back-streaming are discussed in detail. Molecular contamination measurements obtained with a TQCM and witness wafers during two recent integrated system tests of the chamber are presented and discussed. Finally, a concluding remarks section is presented.

A DUST-SETTLING CHAMBER FOR SAMPLING-INSTRUMENT COMPARISON STUDIES

EPA Science Inventory

Introduction: Few methods exist that can evenly and reproducibly deposit dusts onto surfaces for surface-sampling methodological studies. A dust-deposition chamber was designed for that purpose.

Methods: A 1-m3 Rochester-type chamber was modified to produce high airborne d...

16 CFR 1615.4 - Test procedure.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 16 Commercial Practices 2 2011-01-01 2011-01-01 false Test procedure. 1615.4 Section 1615.4... FLAMMABILITY OF CHILDREN'S SLEEPWEAR: SIZES 0 THROUGH 6X (FF 3-71) The Standard § 1615.4 Test procedure. (a) Apparatus—(1) Test chamber. The test chamber shall be a steel cabinet with inside dimensions of 32.9 cm. (12...

Development and Hot-fire Testing of Additively Manufactured Copper Combustion Chambers for Liquid Rocket Engine Applications

NASA Technical Reports Server (NTRS)

Gradl, Paul R.; Greene, Sandy Elam; Protz, Christopher S.; Ellis, David L.; Lerch, Bradley A.; Locci, Ivan E.

2017-01-01

NASA and industry partners are working towards fabrication process development to reduce costs and schedules associated with manufacturing liquid rocket engine components with the goal of reducing overall mission costs. One such technique being evaluated is powder-bed fusion or selective laser melting (SLM), commonly referred to as additive manufacturing (AM). The NASA Low Cost Upper Stage Propulsion (LCUSP) program was designed to develop processes and material characterization for GRCop-84 (a NASA Glenn Research Center-developed copper, chrome, niobium alloy) commensurate with powder-bed AM, evaluate bimetallic deposition, and complete testing of a full scale combustion chamber. As part of this development, the process has been transferred to industry partners to enable a long-term supply chain of monolithic copper combustion chambers. To advance the processes further and allow for optimization with multiple materials, NASA is also investigating the feasibility of bimetallic AM chambers. In addition to the LCUSP program, NASA has completed a series of development programs and hot-fire tests to demonstrate SLM GRCop-84 and other AM techniques. NASA's efforts include a 4K lbf thrust liquid oxygen/methane (LOX/CH4) combustion chamber and subscale thrust chambers for 1.2K lbf LOX/hydrogen (H2) applications that have been designed and fabricated with SLM GRCop-84. The same technologies for these lower thrust applications are being applied to 25-35K lbf main combustion chamber (MCC) designs. This paper describes the design, development, manufacturing and testing of these numerous combustion chambers, and the associated lessons learned throughout their design and development processes.

Reactor for simulation and acceleration of solar ultraviolet damage

NASA Technical Reports Server (NTRS)

Laue, E.; Gupta, A.

1979-01-01

An environmental test chamber providing acceleration of UV radiation and precise temperature control (+ or -)1 C was designed, constructed and tested. This chamber allows acceleration of solar ultraviolet up to 30 suns while maintaining temperature of the absorbing surface at 30 C - 60 C. This test chamber utilizes a filtered medium pressure mercury arc as the source of radiation, and a combination of selenium radiometer and silicon radiometer to monitor solar ultraviolet (295-340 nm) and total radiant power output, respectively. Details of design and construction and operational procedures are presented along with typical test data.

NASA Engineers Test Combustion Chamber to Advance 3-D Printed Rocket Engine Design

NASA Image and Video Library

2016-12-08

A series of test firings like this one in late August brought a group of engineers at NASA's Marshall Space Flight Center in Huntsville, Alabama, a big step closer to their goal of a 100-percent 3-D printed rocket engine, said Andrew Hanks, test lead for the additively manufactured demonstration engine project. The main combustion chamber, fuel turbopump, fuel injector, valves and other components used in the tests were of the team's new design, and all major engine components except the main combustion chamber were 3-D printed. (NASA/MSFC)

Determination of the Kwall correction factor for a cylindrical ionization chamber to measure air-kerma in 60Co gamma beams.

PubMed

Laitano, R F; Toni, M P; Pimpinella, M; Bovi, M

2002-07-21

The factor Kwall to correct for photon attenuation and scatter in the wall of ionization chambers for 60Co air-kerma measurement has been traditionally determined by a procedure based on a linear extrapolation of the chamber current to zero wall thickness. Monte Carlo calculations by Rogers and Bielajew (1990 Phys. Med. Biol. 35 1065-78) provided evidence, mostly for chambers of cylindrical and spherical geometry, of appreciable deviations between the calculated values of Kwall and those obtained by the traditional extrapolation procedure. In the present work an experimental method other than the traditional extrapolation procedure was used to determine the Kwall factor. In this method the dependence of the ionization current in a cylindrical chamber was analysed as a function of an effective wall thickness in place of the physical (radial) wall thickness traditionally considered in this type of measurement. To this end the chamber wall was ideally divided into distinct regions and for each region an effective thickness to which the chamber current correlates was determined. A Monte Carlo calculation of attenuation and scatter effects in the different regions of the chamber wall was also made to compare calculation to measurement results. The Kwall values experimentally determined in this work agree within 0.2% with the Monte Carlo calculation. The agreement between these independent methods and the appreciable deviation (up to about 1%) between the results of both these methods and those obtained by the traditional extrapolation procedure support the conclusion that the two independent methods providing comparable results are correct and the traditional extrapolation procedure is likely to be wrong. The numerical results of the present study refer to a cylindrical cavity chamber like that adopted as the Italian national air-kerma standard at INMRI-ENEA (Italy). The method used in this study applies, however, to any other chamber of the same type.

Diagnostic of structures in heat and power generating industries with utilization of 3D digital image correlation

NASA Astrophysics Data System (ADS)

Malesa, M.; Kujawińska, M.; Malowany, K.; Siwek, B.

2013-04-01

In the paper we present implementation of 3D DIC method for in-situ diagnostic measurements of expansion bellows in heating chambers. The simultaneous measurements of a supply and a return pipeline were carried out in a heating chamber in Warsaw at the peak of the heating season in cooperation with Dalkia Warszawa. Results of the measurements enabled assessment of the risk of failure of expansion bellows. In-situ measurements were preceded by feasibility tests carried out in the Institute of Heat Engineering of Warsaw University of Technology. Potential implementations and a direction of future works are discussed in conclusions.

Nonlinear analysis of shock absorbers with amplitude-dependent damping

NASA Astrophysics Data System (ADS)

Łuczko, Jan; Ferdek, Urszula; Łatas, Waldemar

2018-01-01

This paper contains an analysis of a quarter-car model representing a vehicle equipped with a hydraulic damper whose characteristics are dependent on the piston stroke. The damper, compared to a classical mono-tube damper, has additional internal chambers. Oil flow in those chambers is controlled by relative piston displacement. The proposed nonlinear model of the system is aimed to test the effect of key design parameters of the damper on the quality indices representing ride comfort and driving safety. Numerical methods were used to determine the characteristic curves of the damper and responses of the system to harmonic excitations with their amplitude decreasing as the values of frequency increase.

Performance Increase Verification for a Bipropellant Rocket Engine

NASA Technical Reports Server (NTRS)

Alexander, Leslie; Chapman, Jack; Wilson, Reed; Krismer, David; Lu, Frank; Wilson, Kim; Miller, Scott; England, Chris

2008-01-01

Component performance assessment testing for a, pressure-fed earth storable bipropellant rocket engine was successfully completed at Aerojet's Redmond test facility. The primary goal of the this development project is to increase the specific impulse of an apogee class bi-propellant engine to greater than 330 seconds with nitrogen tetroxide and monomethylhydrazine propellants and greater than 335 seconds with nitrogen tetroxide and hydrazine. The secondary goal of the project is to take greater advantage of the high temperature capabilities of iridium/rhenium chambers. In order to achieve these goals, the propellant feed pressures were increased to 400 psia, nominal, which in turn increased the chamber pressure and temperature, allowing for higher c*. The tests article used a 24-on-24 unlike doublet injector design coupled with a copper heat sink chamber to simulate a flight configuration combustion chamber. The injector is designed to produce a nominal 200 lbf of thrust with a specific impulse of 335 seconds (using hydrazine fuel). Effect of Chamber length on engine C* performance was evaluated with the use of modular, bolt-together test hardware and removable chamber inserts. Multiple short duration firings were performed to characterize injector performance across a range of thrust levels, 180 to 220 lbf, and mixture ratios, from 1.1 to 1.3. During firing, ignition transient, chamber pressure, and various temperatures were measured in order to evaluate the performance of the engine and characterize the thermal conditions. The tests successfully demonstrated the stable operation and performance potential of a full scale engine with a measured c* of XXXX ft/sec (XXXX m/s) under nominal operational conditions.

Relocation of the Cryo-Test Facility to NASA-MSFC

NASA Technical Reports Server (NTRS)

Sisco, Jimmy D.; McConnaughey, Paul K. (Technical Monitor)

2002-01-01

The Environmental Test Facility (ETF), located at NASA-Marshall Space Flight Center, Huntsville, Alabama, has provided thermal vacuum testing for several major programs since the 1960's. The ETF consists of over 13 thermal vacuum chambers sized and configured to handle the majority of test payloads. Testing is performed around the clock with multiple tests being conducted simultaneously. Chamber selection to achieve the best match with test articles and juggling program schedules, at times, can be a challenge. The ETF's Sunspot chamber has had tests scheduled and operated back-to-back for several years and provides the majority of schedule conflicts. Future test programs have been identified which surpass the current Sunspot availability. This paper describes a very low cost alternate to reduce schedule conflicts by utilizing government excess equipment

A Regeneratively Cooled Thrust Chamber For The Fastrac Engine

NASA Technical Reports Server (NTRS)

Brown, Kendall K.; Sparks, Dave; Woodcock, Gordon

2000-01-01

Abstract This paper presents the development of a low-cost, regeneratively-cooled thrust chamber for the Fastrac engine. The chamber was fabricated using hydraformed copper tubing to form the coolant jacket and wrapped with a fiber reinforced polymer composite Material to form a structural jacket. The thrust chamber design and fabrication approach was based upon Space America. Inc.'s 12,000 lb regeneratively-cooled LOX/kerosene rocket engine. Fabrication of regeneratively cooled thrust chambers by tubewall construction dates back to the early US ballistic missile programs. The most significant innovations in this design was the development of a low-cost process for fabrication from copper tubing (nickel alloy was the usual practice) and use of graphite composite overwrap as the pressure containment, which yields an easily fabricated, lightweight pressure jacket around the copper tubes A regeneratively-cooled reusable thrust chamber can benefit the Fastrac engine program by allowing more efficient (cost and scheduler testing). A proof-of-concept test article has been fabricated and will he tested at Marshall Space Flight Center in the late Summer or Fall of 2000.

Performance of a Compression-ignition Engine with a Precombustion Chamber Having High-Velocity Air Flow

NASA Technical Reports Server (NTRS)

Spanogle, J A; Moore, C S

1931-01-01

Presented here are the results of performance tests made with a single-cylinder, four stroke cycle, compression-ignition engine. These tests were made on a precombustion chamber type of cylinder head designed to have air velocity and tangential air flow in both the chamber and cylinder. The performance was investigated for variable load and engine speed, type of fuel spray, valve opening pressure, injection period and, for the spherical chamber, position of the injection spray relative to the air flow. The pressure variations between the pear-shaped precombustion chamber and the cylinder for motoring and full load conditions were determined with a Farnboro electric indicator. The combustion chamber designs tested gave good mixing of a single compact fuel spray with the air, but did not control the ensuing combustion sufficiently. Relative to each other, the velocity of air flow was too high, the spray dispersion by injection too great, and the metering effect of the cylinder head passage insufficient. The correct relation of these factors is of the utmost importance for engine performance.

Tuned Chamber Core Panel Acoustic Test Results

NASA Technical Reports Server (NTRS)

Schiller, Noah H.; Allen, Albert R.

2016-01-01

This report documents acoustic testing of tuned chamber core panels, which can be used to supplement the low-frequency performance of conventional acoustic treatment. The tuned chamber core concept incorporates low-frequency noise control directly within the primary structure and is applicable to sandwich constructions with a directional core, including corrugated-, truss-, and fluted-core designs. These types of sandwich structures have long, hollow channels (or chambers) in the core. By adding small holes through one of the facesheets, the hollow chambers can be utilized as an array of low-frequency acoustic resonators. These resonators can then be used to attenuate low-frequency noise (below 400 Hz) inside a vehicle compartment without increasing the weight or size of the structure. The results of this test program demonstrate that the tuned chamber core concept is effective when used in isolation or combined with acoustic foam treatments. Specifically, an array of acoustic resonators integrated within the core of the panels was shown to improve both the low-frequency absorption and transmission loss of the structure in targeted one-third octave bands.

Issues Related to Large Flight Hardware Acoustic Qualification Testing

NASA Technical Reports Server (NTRS)

Kolaini, Ali R.; Perry, Douglas C.; Kern, Dennis L.

2011-01-01

The characteristics of acoustical testing volumes generated by reverberant chambers or a circle of loudspeakers with and without large flight hardware within the testing volume are significantly different. The parameters attributing to these differences are normally not accounted for through analysis or acoustic tests prior to the qualification testing without the test hardware present. In most cases the control microphones are kept at least 2-ft away from hardware surfaces, chamber walls, and speaker surfaces to minimize the impact of the hardware in controlling the sound field. However, the acoustic absorption and radiation of sound by hardware surfaces may significantly alter the sound pressure field controlled within the chamber/speaker volume to a given specification. These parameters often result in an acoustic field that may provide under/over testing scenarios for flight hardware. In this paper the acoustic absorption by hardware surfaces will be discussed in some detail. A simple model is provided to account for some of the observations made from Mars Science Laboratory spacecraft that recently underwent acoustic qualification tests in a reverberant chamber.

Growth, chamber building rate and reproduction time of Palaeonummulites venosus under natural conditions.

NASA Astrophysics Data System (ADS)

Kinoshita, Shunichi; Eder, Wolfgang; Wöger, Julia; Hohenegger, Johann; Briguglio, Antonino

2017-04-01

Investigations on Palaeonummulites venosus using the natural laboratory approach for determining chamber building rate, test diameter increase rate, reproduction time and longevity is based on the decomposition of monthly obtained frequency distributions based on chamber number and test diameter into normal-distributed components. The shift of the component parameters 'mean' and 'standard deviation' during the investigation period of 15 months was used to calculate Michaelis-Menten functions applied to estimate the averaged chamber building rate and diameter increase rate under natural conditions. The individual dates of birth were estimated using the inverse averaged chamber building rate and the inverse diameter increase rate fitted by the individual chamber number or the individual test diameter at the sampling date. Distributions of frequencies and densities (i.e. frequency divided by sediment weight) based on chamber building rate and diameter increase rate resulted both in a continuous reproduction through the year with two peaks, the stronger in May /June determined as the beginning of the summer generation (generation1) and the weaker in November determined as the beginning of the winter generation (generation 2). This reproduction scheme explains the existence of small and large specimens in the same sample. Longevity, calculated as the maximum difference in days between the individual's birth date and the sampling date seems to be round about one year, obtained by both estimations based on the chamber building rate and the diameter increase rate.

Design, fabrication, and performance testing of a vacuum chamber for pulse compressor of a 150 TW Ti:sapphire laser

NASA Astrophysics Data System (ADS)

Tripathi, P. K.; Singh, Rajvir; Bhatnagar, V. K.; Sharma, S. D.; Sharma, Sanjay; Sisodia, B.; Yedle, K.; Kushwaha, R. P.; Sebastin, S.; Mundra, G.

2012-11-01

A vacuum chamber, to house the optical pulse compressor of a 150 TW Ti:sapphire laser system, has been designed, fabricated, and tested. As the intensity of the laser pulse becomes very high after pulse compression, there is phase distortion of the laser beam in air. Hence, the beam (after pulse compression) has to be transported in vacuum to avoid this distortion, which affects the laser beam focusability. A breadboard with optical gratings and reflective optics for compression of the optical pulse has to be kept inside the chamber. The chamber is made of SS 316L material in cuboidal shape with inside dimensions 1370×1030×650 mm3, with rectangular and circular demountable ports for entry and exit of the laser beam, evacuation, system cables, and ports to access optics mounted inside the chamber. The front and back sides of the chamber are kept demountable in order to insert the breadboard with optical components mounted on it. Leak tightness of 9×10-9 mbar-lit/sec in all the joints and ultimate vacuum of 6.5×10-6 mbar was achieved in the chamber using a turbo molecular pumping system. The paper describe details of the design/ features of the chamber, important procedure involved in machining, fabrication, processing and final testing.

Evaluation of Impinging Stream Vortex Chamber Concepts for Liquid Rocket Engine Applications

NASA Technical Reports Server (NTRS)

Trinh, Huu; Kopicz, Charles; Bullard, Brad; Michaels, Scott

2003-01-01

NASA Marshall Space Flight Center (MSFC) and the U. S. Army are jointly investigating vortex chamber concepts for cryogenic oxygen/hydrocarbon fuel rocket engine applications. One concept, the Impinging Stream Vortex Chamber Concept (ISVC), has been tested with gel propellants at AMCOM at Redstone Arsenal, Alabama. A version of this concept for the liquid oxygen (LOX)/hydrocarbon fuel (RP-1) propellant system is derived from the one for the gel propellant. An unlike impinging injector is employed to deliver the propellants to the chamber. MSFC has also designed two alternative injection schemes, called the chasing injectors, associated with this vortex chamber concept. In these injection techniques, both propellant jets and their impingement point are in the same chamber cross-sectional plane. One injector has a similar orifice size with the original unlike impinging injector. The second chasing injector has small injection orifices. The team has achieved their objectives of demonstrating the self-cooled chamber wall benefits of ISVC and of providing the test data for validating computational fluids dynamics (CFD) models. These models, in turn, will be used to design the optimum vortex chambers in the future.

Method and apparatus to characterize ultrasonically reflective contrast agents

NASA Technical Reports Server (NTRS)

Pretlow, Robert A., III (Inventor)

1993-01-01

A method and apparatus for characterizing the time and frequency response of an ultrasonically reflective contrast agent is disclosed. An ultrasonically reflective contrast agent is injected, under constant pressure, into a fluid flowing through a pump flow circuit. The fluid and the ultrasonically reflective contrast agent are uniformly mixed in a mixing chamber, and the uniform mixture is passed through a contrast agent chamber. The contrast agent chamber is acoustically and axially interposed between an ultrasonic transducer chamber and an acoustic isolation chamber. A pulse of ultrasonic energy is transmitted into the contrast agent chamber from the ultrasonic transducer chamber. An echo waveform is received from the ultrasonically reflective contrast agent, and it is analyzed to determine the time and frequency response of the ultrasonically reflective contrast agent.

The 1991 LLWAS anemometer test program

NASA Astrophysics Data System (ADS)

Phillips, Charles O.; Burnham, David; Jacobs, Leo; Hazen, David

1992-09-01

Performance tests of anemometers under icing and snow conditions were conducted during 1990-1991 on the test field at Rochester, MN and in icing chambers and wind tunnels at Sterling, VA. These tests were done for the FAA Low Level Windshear Alert System (LLWAS) program to test sensors for the next phase of LLWAS. Sensors from ten manufacturers were accepted into the test program from the respondents to the Commerce Business Daily. These sensors were required first to pass an icing chamber test in order to be field tested. The field tests lasted from Nov. 1990 to Jul. 1991. Afterwards, all sensors were sent to Sterling, VA for wind tunnel tests in September 1991. All units from the eight manufacturers that passed the icing chamber test were in the field test. A propeller/vane sensor that failed the icing chamber test was put in the field as a reference. All the units that passed were not affected by icing during the field test although a mechanical unit was affected by snow during one event. The propeller/vane was affected by icing during one event. Wind tunnel tests were done to check starting thresholds and calibration anomalies found in the field. It was concluded that there is no one winning technology that could be found from the tests.

Discharge Chamber Primary Electron Modeling Activities in Three-Dimensions

NASA Technical Reports Server (NTRS)

Steuber, Thomas J.

2004-01-01

Designing discharge chambers for ion thrusters involves many geometric configuration decisions. Various decisions will impact discharge chamber performance with respect to propellant utilization efficiency, ion production costs, and grid lifetime. These hardware design decisions can benefit from the assistance of computational modeling. Computational modeling for discharge chambers has been limited to two-dimensional codes that leveraged symmetry for interpretation into three-dimensional analysis. This paper presents model development activities towards a three-dimensional discharge chamber simulation to aid discharge chamber design decisions. Specifically, of the many geometric configuration decisions toward attainment of a worthy discharge chamber, this paper focuses on addressing magnetic circuit considerations with a three-dimensional discharge chamber simulation as a tool. With this tool, candidate discharge chamber magnetic circuit designs can be analyzed computationally to gain insight into factors that may influence discharge chamber performance such as: primary electron loss width in magnetic cusps, cathode tip position with respect to the low magnetic field volume, definition of a low magnetic field region, and maintenance of a low magnetic field region across the grid span. Corroborating experimental data will be obtained from mockup hardware tests. Initially, simulated candidate magnetic circuit designs will resemble previous successful thruster designs. To provide opportunity to improve beyond previous performance benchmarks, off-design modifications will be simulated and experimentally tested.

Method for measuring anterior chamber volume by image analysis

NASA Astrophysics Data System (ADS)

Zhai, Gaoshou; Zhang, Junhong; Wang, Ruichang; Wang, Bingsong; Wang, Ningli

2007-12-01

Anterior chamber volume (ACV) is very important for an oculist to make rational pathological diagnosis as to patients who have some optic diseases such as glaucoma and etc., yet it is always difficult to be measured accurately. In this paper, a method is devised to measure anterior chamber volumes based on JPEG-formatted image files that have been transformed from medical images using the anterior-chamber optical coherence tomographer (AC-OCT) and corresponding image-processing software. The corresponding algorithms for image analysis and ACV calculation are implemented in VC++ and a series of anterior chamber images of typical patients are analyzed, while anterior chamber volumes are calculated and are verified that they are in accord with clinical observation. It shows that the measurement method is effective and feasible and it has potential to improve accuracy of ACV calculation. Meanwhile, some measures should be taken to simplify the handcraft preprocess working as to images.

Method for sequentially processing a multi-level interconnect circuit in a vacuum chamber

NASA Technical Reports Server (NTRS)

Routh, D. E.; Sharma, G. C. (Inventor)

1982-01-01

The processing of wafer devices to form multilevel interconnects for microelectronic circuits is described. The method is directed to performing the sequential steps of etching the via, removing the photo resist pattern, back sputtering the entire wafer surface and depositing the next layer of interconnect material under common vacuum conditions without exposure to atmospheric conditions. Apparatus for performing the method includes a vacuum system having a vacuum chamber in which wafers are processed on rotating turntables. The vacuum chamber is provided with an RF sputtering system and a DC magnetron sputtering system. A gas inlet is provided in the chamber for the introduction of various gases to the vacuum chamber and the creation of various gas plasma during the sputtering steps.

Head-space, small-chamber and in-vehicle tests for volatile organic compounds (VOCs) emitted from air fresheners for the Korean market.

PubMed

Jo, Wan-Kuen; Lee, Jong-Hyo; Kim, Mo-Keun

2008-02-01

The present study investigated the emission characteristics of gel-type air fresheners (AFs), using head-space, small-chamber, and in-vehicle tests. Five toxic or hazardous analytes were found in the headspace phase of AFs (toluene, benzene, ethyl benzene, and m,p-xylene) at a frequency of more than 50%. Limonene and linalool, which are known to be unsaturated ozone-reactive VOCs, were detected at a frequency of 58 and 35%, respectively. The empirical model fitted well with the time-series concentrations in the chamber, thereby suggesting that the empirical model was suitable for testing emissions. Limonene exhibited the highest emission rate, followed by m,p-xylene, toluene, ethyl benzene, and benzene. For most target VOCs, higher air change per hour (ACH) levels exhibited increased emission rates. In contrast, higher ACH levels resulted in lower chamber concentrations. The mean concentration of limonene was significantly higher in passenger cars with an AF than without. For other target compounds, there were no significant differences between the two conditions tested. Consequently, it was suggested that unlike limonene, the emission strength for aromatic compounds identified in the chamber tests was not strong enough to elevate in-vehicle levels.

KSC-99pp0236

NASA Image and Video Library

1999-02-25

KENNEDY SPACE CENTER, FLA. -- At a ribbon-cutting ceremony inside the Operations and Checkout Building high bay, Sterling Walker, director of Engineering Development, introduces the project team members responsible for renovating an altitude chamber formerly used on the Apollo program. In addition, management, media and onlookers are present for the ceremony. Seated in the front row left are (left to right) Terry Smith, director of Engineering, Boeing Space Coast Operations; Steve Francois, director, Space Station and Shuttle Payloads; Jay Greene, International Space Station manager for Technical; and Roy Bridges, center director. The chamber was reactivated, after a 24-year hiatus, to perform leak tests on International Space Station pressurized modules at the launch site. Originally, two chambers were built to test the Apollo command and lunar service modules. They were last used in 1975 during the Apollo-Soyuz Test Project. After installation of new vacuum pumping equipment and controls, a new control room, and a new rotation handling fixture, the chamber again became operational in February 1999. The chamber, which is 33 feet in diameter and 50 feet tall, is constructed of stainless steel. The first module that will be tested for leaks is the U.S. Laboratory. No date has been determined for the test

Testing of electroformed deposited iridium/powder metallurgy rhenium rockets

NASA Technical Reports Server (NTRS)

Reed, Brian D.; Dickerson, Robert

1996-01-01

High-temperature, oxidation-resistant chamber materials offer the thermal margin for high performance and extended lifetimes for radiation-cooled rockets. Rhenium (Re) coated with iridium (Ir) allow hours of operation at 2200 C on Earth-storable propellants. One process for manufacturing Ir/Re rocket chambers is the fabrication of Re substrates by powder metallurgy (PM) and the application of Ir coatings by using electroformed deposition (ED). ED Ir coatings, however, have been found to be porous and poorly adherent. The integrity of ED Ir coatings could be improved by densification after the electroforming process. This report summarizes the testing of two 22-N, ED Ir/PM Re rocket chambers that were subjected to post-deposition treatments in an effort to densify the Ir coating. One chamber was vacuum annealed, while the other chamber was subjected to hot isostatic pressure (HIP). The chambers were tested on gaseous oxygen/gaseous hydrogen propellants, at mixture ratios that simulated the oxidizing environments of Earth-storable propellants. ne annealed ED Ir/PM Re chamber was tested for a total of 24 firings and 4.58 hr at a mixture ratio of 4.2. After only 9 firings, the annealed ED Ir coating began to blister and spall upstream of the throat. The blistering and spalling were similar to what had been experienced with unannealed, as-deposited ED Ir coatings. The HIP ED Ir/PM Re chamber was tested for a total of 91 firings and 11.45 hr at mixture ratios of 3.2 and 4.2. The HIP ED Ir coating remained adherent to the Re substrate throughout testing; there were no visible signs of coating degradation. Metallography revealed, however, thinning of the HIP Ir coating and occasional pores in the Re layer upstream of the throat. Pinholes in the Ir coating may have provided a path for oxidation of the Re substrate at these locations. The HIP ED Ir coating proved to be more effective than vacuum annealed and as-deposited ED Ir. Further densification is still required to match the integrity of chemically vapor deposited Ir coatings. Despite this, the successful long duration testing of the HIP ED Ir chamber, in an oxidizing environment comparable to Earth-storable propellants, demonstrated the viability of this Ir/Re rocket fabrication process.

Low-cycle fatigue analysis of a cooled copper combustion chamber

NASA Technical Reports Server (NTRS)

Miller, R. W.

1974-01-01

A three-dimensional finite element elastoplastic strain analysis was performed for the throat section of regeneratively cooled rocket engine combustion chamber. The analysis included thermal and pressure loads, and the effects of temperature dependent material properties, to determine the strain range corresponding to the engine operating cycle. The strain range was used in conjunction with OFHC copper isothermal fatigue test data to predict engine low-cycle fatigue life. The analysis was performed for chamber configuration and operating conditions corresponding to a hydrogen-oxygen chamber which was fatigue tested to failure at the NASA Lewis Research Center.

Commissioning of a well type chamber for HDR and LDR brachytherapy applications: a review of methodology and outcomes.

PubMed

Mukwada, Godfrey; Neveri, Gabor; Alkhatib, Zaid; Waterhouse, David K; Ebert, Martin

2016-03-01

For safe and accurate dose delivery in brachytherapy, associated equipment is subject to commissioning and ongoing quality assurance (QA). Many centres depend on the use of a well-type chamber ('well chamber') for performing brachytherapy dosimetry. Documentation of well chamber commissioning is scarce despite the important role the chamber plays in the whole brachytherapy QA process. An extensive and structured commissioning of the HDR 1000 plus well chamber (Standard Imaging Inc, Middleton WI) for HDR and LDR dosimetry was undertaken at Sir Charles Gairdner Hospital. The methodology and outcomes of this commissioning is documented and presented as a guideline to others involved in brachytherapy. The commissioning tests described include mechanical integrity, leakage current, directional dependence, response, length of uniform response, the influence of insert holders, ion collection efficiency, polarity effect, accuracy of measured air kerma strength (S(K)) or reference air kerma rate (K(R)) and baseline setting (for ongoing constancy checks). For the HDR 1000 plus well chamber, some of the insert holders modify the response curve. The measured sweet length was 2.5 cm which is within 0.5% of that specified by the manufacturer. Correction for polarity was negligible (0.9999) and ion recombination was small (0.9994). Directional dependence was small (less than 0.2%) and leakage current was negligible. The measured K(R) for (192)Ir agreed within 0.11% compared with a second well chamber of similar model and was within 0.5% of that determined via a free-in-air measurement method. Routine constancy checks over a year agreed with the baseline within 0.4%.

Development of a Methodology for Conducting Hall Thruster EMI Tests in Metal Vacuum Chambers of Arbitrary Shape and Size

NASA Technical Reports Server (NTRS)

Gallimore, Alec D.

2000-01-01

While the closed-drift Hall thruster (CDT) offers significant improvement in performance over conventional chemical rockets and other advanced propulsion systems such as the arcjet, its potential impact on spacecraft communication signals must be carefully assessed before widespread use of this device can take place. To this end, many of the potentially unique issues that are associated with these thrusters center on its plume plasma characteristics and the its interaction with electromagnetic waves. Although a great deal of experiments have been made in characterizing the electromagnetic interference (EMI) potential of these thrusters, the interpretation of the resulting data is difficult because most of these measurements have been made in vacuum chambers with metal walls which reflect radio waves emanating from the thruster. This project developed a means of assessing the impact of metal vacuum chambers of arbitrary size or shape on EMI experiments, thereby allowing for test results to be interpreted properly. Chamber calibration techniques were developed and initially tested at RIAME using their vacuum chamber. Calibration experiments were to have been made at Tank 5 of NASA GRC and the 6 m by 9 m vacuum chamber at the University of Michigan to test the new procedure, however the subcontract to RIAME was cancelled by NASA memorandum on Feb. 26. 1999.

Pressure chamber tests of eustachian tube function document lower efficiency in adults with colds when compared to without colds.

PubMed

Doyle, William J; Singla, Alok; Banks, Juliane; El-Wagaa, Jenna; Swarts, J Douglas

2014-07-01

Fractional gradient equilibrated (FGE) for ears with applied positive but not negative middle ear (ME)-ambient pressure gradients is highly sensitive to a cold-like illness (CLI). The sequential development of eustachian tube (ET) dysfunction, ME under-pressure, and otitis media (OM) characterizes many children during a CLI. If linked, OM burden would be lessened by interventions that promote/preserve good ET function during a CLI. Evaluating this requires a quantitative ET function test for MEs with an intact tympanic membrane responsive to a CLI. Pressure chamber testing of ET function was performed at +200 and -200 daPa in 3 groups of adults: group I, 21 subjects with an extant CLI and groups II and III, 14 and 57 adults, respectively, without a CLI. ME-chamber pressure gradient was recorded by tympanometry before and after the subject swallowed twice. ET functional efficiency was quantified as the FGE, which was then compared among groups using a Mann-Whitney U test. At chamber pressures of 200 daPa, the ME-chamber pressure gradient was negative, and FGE was low and not different among groups. At chamber pressures of -200 daPa that gradient was positive, and FGE was significantly higher in groups II and III when compared with group I.

40 CFR Table F-2 to Subpart F of... - Particle Sizes and Wind Speeds for Full Wind Tunnel Test, Wind Tunnel Inlet Aspiration Test, and...

Code of Federal Regulations, 2012 CFR

2012-07-01

... Wind Tunnel Test, Wind Tunnel Inlet Aspiration Test, and Static Chamber Test F Table F-2 to Subpart F... Part 53—Particle Sizes and Wind Speeds for Full Wind Tunnel Test, Wind Tunnel Inlet Aspiration Test, and Static Chamber Test Primary Partical Mean Size a (µm) Full Wind Tunnel Test 2 km/hr 24 km/hr Inlet...

40 CFR Table F-2 to Subpart F of... - Particle Sizes and Wind Speeds for Full Wind Tunnel Test, Wind Tunnel Inlet Aspiration Test, and...

Code of Federal Regulations, 2013 CFR

2013-07-01

... Wind Tunnel Test, Wind Tunnel Inlet Aspiration Test, and Static Chamber Test F Table F-2 to Subpart F... Part 53—Particle Sizes and Wind Speeds for Full Wind Tunnel Test, Wind Tunnel Inlet Aspiration Test, and Static Chamber Test Primary Partical Mean Size a (µm) Full Wind Tunnel Test 2 km/hr 24 km/hr Inlet...

40 CFR Table F-2 to Subpart F of... - Particle Sizes and Wind Speeds for Full Wind Tunnel Test, Wind Tunnel Inlet Aspiration Test, and...

Code of Federal Regulations, 2014 CFR

2014-07-01

... Wind Tunnel Test, Wind Tunnel Inlet Aspiration Test, and Static Chamber Test F Table F-2 to Subpart F... Part 53—Particle Sizes and Wind Speeds for Full Wind Tunnel Test, Wind Tunnel Inlet Aspiration Test, and Static Chamber Test Primary Partical Mean Size a (µm) Full Wind Tunnel Test 2 km/hr 24 km/hr Inlet...

Long term performance studies of large oil-free bakelite resistive plate chamber

NASA Astrophysics Data System (ADS)

Ganai, R.; Roy, A.; Shiroya, M. K.; Agarwal, K.; Ahammed, Z.; Choudhury, S.; Chattopadhyay, S.

2016-09-01

Several high energy physics and neutrino physics experiments worldwide require large-size RPCs to cover wide acceptances. The muon tracking systems in the Iron calorimeter (ICAL) experiment in the India based Neutrino Observatory (INO), India and the near detector in Deep Underground Neutrino Experiment (DUNE) at Fermilab are two such examples. A single gap bakelite RPC of dimension 240 cm × 120 cm, with gas gap of 0.2 cm, has been built and tested at Variable Energy Cyclotron Centre, Kolkata, using indigenous materials procured from the local market. No additional lubricant, like oil has been used on the electrode surfaces for smoothening. The chamber is in operation for > 365 days. We have tested the chamber for its long term operation. The leakage current, bulk resistivity, efficiency, noise rate and time resolution of the chamber have been found to be quite stable during the testing peroid. It has shown an efficiency > 95% with an average time resolution of ~ 0.83 ns at the point of measurement at ~ 8700 V throughout the testing period. Details of the long term performance of the chamber have been discussed.

16 CFR § 1615.4 - Test procedure.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 16 Commercial Practices 2 2013-01-01 2013-01-01 false Test procedure. § 1615.4 Section § 1615.4... FLAMMABILITY OF CHILDREN'S SLEEPWEAR: SIZES 0 THROUGH 6X (FF 3-71) The Standard § 1615.4 Test procedure. (a) Apparatus—(1) Test chamber. The test chamber shall be a steel cabinet with inside dimensions of 32.9 cm...

Recent Improvements to the Acoustical Testing Laboratory at the NASA Glenn Research Center

NASA Technical Reports Server (NTRS)

Podboy, Devin M.; Mirecki, Julius H.; Walker, Bruce E.; Sutliff, Daniel L.

2014-01-01

The Acoustical Testing Laboratory (ATL) consists of a 27- by 23- by 20-ft (height) convertible hemi/anechoic chamber and separate sound-attenuating test support enclosure. Absorptive fiberglass wedges in the test chamber provide an anechoic environment down to 100 Hz. A spring-isolated floor system affords vibration isolation above 3 Hz. These specifications, along with very low design background levels, enable the acquisition of accurate and repeatable acoustical measurements on test articles that produce very low sound pressures. Removable floor wedges allow the test chamber to operate in either a hemi-anechoic or anechoic configuration, depending on the size of the test article and the specific test being conducted. The test support enclosure functions as a control room during normal operations. Recently improvements were accomplished in support of continued usage of the ATL by NASA programs including an analysis of the ultra-sonic characteristics. A 3-D traverse system inside the chamber was utilized for acquiring acoustic data for these tests. The traverse system drives a linear array of 13, 1/4 in.-microphones spaced 3 in. apart (36 in. span). An updated data acquisition system was also incorporated into the facility.

Recent Improvements to the Acoustical Testing Laboratory at the NASA Glenn Research Center

NASA Technical Reports Server (NTRS)

Podboy, Devin M.; Mirecki, Julius H.; Walker, Bruce E.; Sutliff, Daniel L.

2014-01-01

The Acoustical Testing Laboratory (ATL) consists of a 27 by 23 by 20 ft (height) convertible hemi/anechoic chamber and separate sound-attenuating test support enclosure. Absorptive fiberglass wedges in the test chamber provide an anechoic environment down to 100 Hz. A spring-isolated floor system affords vibration isolation above 3 Hz. These specifications, along with very low design background levels, enable the acquisition of accurate and repeatable acoustical measurements on test articles that produce very low sound pressures. Removable floor wedges allow the test chamber to operate in either a hemi-anechoic or anechoic configuration, depending on the size of the test article and the specific test being conducted. The test support enclosure functions as a control room during normal operations. Recently improvements were accomplished in support of continued usage of the ATL by NASA programs including an analysis of the ultra-sonic characteristics. A 3 dimensional traverse system inside the chamber was utilized for acquiring acoustic data for these tests. The traverse system drives a linear array of 13, 1/4"-microphones spaced 3" apart (36" span). An updated data acquisition system was also incorporated into the facility.

Technical Capability Upgrades to the NASA Langley Research Center 6 ft. by 6 ft. Thermal Vacuum Chamber

NASA Technical Reports Server (NTRS)

Thornblom, Mark N.; Beverly, Joshua; O'Connell, Joseph J.; Mau, Johnny C.; Duncan, Dwight L.

2014-01-01

The 6 ft. by 6 ft. thermal vacuum chamber (TVAC), housed in Building 1250 at the NASA Langley Research Center (LaRC), and managed by the Systems Integration and Test Branch within the Engineering Directorate, has undergone several significant modifications to increase testing capability, safety, and quality of measurements of articles under environmental test. Significant modifications include: a new nitrogen thermal conditioning unit for controlling shroud temperatures from -150degC to +150degC; two horizontal auxiliary cold plates for independent temperature control from -150degC to +200degC; a suite of contamination monitoring sensors for outgassing measurements and species identification; signal and power feed-throughs; new pressure gauges; and a new data acquisition and control commanding system including safety interlocks. This presentation will provide a general overview of the LaRC 6 ft. by 6 ft. TVAC chamber, an overview of the new technical capabilities, and illustrate each upgrade in detail, in terms of mechanical design and predicted performance. Additionally, an overview of the scope of tests currently being performed in the chamber will be documented, and sensor plots from tests will be provided to show chamber temperature and pressure performance with actual flight hardware under test.

An experimental investigation devoted to determine heat transfer characteristics in a radiant ceiling heating system

NASA Astrophysics Data System (ADS)

Koca, Aliihsan; Acikgoz, Ozgen; Çebi, Alican; Çetin, Gürsel; Dalkilic, Ahmet Selim; Wongwises, Somchai

2018-02-01

Investigations on heated ceiling method can be considered as a new research area in comparison to the common wall heating-cooling and cooled ceiling methods. In this work, heat transfer characteristics of a heated radiant ceiling system was investigated experimentally. There were different configurations for a single room design in order to determine the convective and radiative heat transfer rates. Almost all details on the arrangement of the test chamber, hydraulic circuit and radiant panels, the measurement equipment and experimental method including uncertainty analysis were revealed in detail indicating specific international standards. Total heat transfer amount from the panels were calculated as the sum of radiation to the unheated surfaces, convection to the air, and conduction heat loss from the backside of the panels. Integral expression of the view factors was calculated by means of the numerical evaluations using Matlab code. By means of this experimental chamber, the radiative, convective and total heat-transfer coefficient values along with the heat flux values provided from the ceiling to the unheated surrounding surfaces have been calculated. Moreover, the details of 28 different experimental case study measurements from the experimental chamber including the convective, radiative and total heat flux, and heat output results are given in a Table for other researchers to validate their theoretical models and empirical correlations.

Mean-free-paths in concert and chamber music halls and the correct method for calibrating dodecahedral sound sources.

PubMed

Beranek, Leo L; Nishihara, Noriko

2014-01-01

The Eyring/Sabine equations assume that in a large irregular room a sound wave travels in straight lines from one surface to another, that the surfaces have an average sound absorption coefficient αav, and that the mean-free-path between reflections is 4 V/Stot where V is the volume of the room and Stot is the total area of all of its surfaces. No account is taken of diffusivity of the surfaces. The 4 V/Stot relation was originally based on experimental determinations made by Knudsen (Architectural Acoustics, 1932, pp. 132-141). This paper sets out to test the 4 V/Stot relation experimentally for a wide variety of unoccupied concert and chamber music halls with seating capacities from 200 to 5000, using the measured sound strengths Gmid and reverberation times RT60,mid. Computer simulations of the sound fields for nine of these rooms (of varying shapes) were also made to determine the mean-free-paths by that method. The study shows that 4 V/Stot is an acceptable relation for mean-free-paths in the Sabine/Eyring equations except for halls of unusual shape. Also demonstrated is the proper method for calibrating the dodecahedral sound source used for measuring the sound strength G, i.e., the reverberation chamber method.

Evaluation of the TrueBeam machine performance check (MPC) beam constancy checks for flattened and flattening filter-free (FFF) photon beams.

PubMed

Barnes, Michael P; Greer, Peter B

2017-01-01

Machine Performance Check (MPC) is an automated and integrated image-based tool for verification of beam and geometric performance of the TrueBeam linac. The aims of the study were to evaluate the MPC beam performance tests against current daily quality assurance (QA) methods, to compare MPC performance against more accurate monthly QA tests and to test the sensitivity of MPC to changes in beam performance. The MPC beam constancy checks test the beam output, uniformity, and beam center against the user defined baseline. MPC was run daily over a period of 5 months (n = 115) in parallel with the Daily QA3 device. Additionally, IC Profiler, in-house EPID tests, and ion chamber measurements were performed biweekly and results presented in a form directly comparable to MPC. The sensitivity of MPC was investigated using controlled adjustments of output, beam angle, and beam position steering. Over the period, MPC output agreed with ion chamber to within 0.6%. For an output adjustment of 1.2%, MPC was found to agree with ion chamber to within 0.17%. MPC beam center was found to agree with the in-house EPID method within 0.1 mm. A focal spot position adjustment of 0.4 mm (at isocenter) was measured with MPC beam center to within 0.01 mm. An average systematic offset of 0.5% was measured in the MPC uniformity and agreement of MPC uniformity with symmetry measurements was found to be within 0.9% for all beams. MPC uniformity detected a change in beam symmetry of 1.5% to within 0.3% and 0.9% of IC Profiler for flattened and FFF beams, respectively. © 2016 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.

Measurement of N2O and CH4 soil fluxes from garden, agricultural and natural soils using both closed and open chamber systems coupled with high-precision CRDS analyzer

NASA Astrophysics Data System (ADS)

He, Yonggang; Jacobson, Gloria; Alexander, Chris; Fleck, Derek; Hoffnagel, John; Del Campo, Bernardo; Rella, Chris

2013-04-01

Studying the emission and uptake of greenhouse gases from soil is essential for understanding, adapting to and ultimately mitigating the effects of climate change. To-date, majority of such studies have been focused on carbon dioxide (CO2 ) , however, in 2006 the EPA estimated that "Agricultural activities currently generate the largest share, 63 percent, of the world's anthropogenic non-carbon dioxide (non-CO2) emissions (84 percent of nitrous oxide [N2O] and 52 percent of methane[CH4]), and make up roughly 15 percent of all anthropogenic greenhouse gas emissions" (Prentice et al., 2001). Therefore, enabling accurate N2O and CH4 flux measurements in the field are clearly critical to our ability to better constrain carbon and nitrogen budgets, characterize soil sensitivities, agricultural practices, and microbial processes like denitrification and nitrification. To aide in these studies, Picarro has developed a new analyzer based on its proven, NIR technology platform, which is capable of measuring both N2O and CH4 down to ppb levels in a single, field-deployable analyzer. This analyzer measures N2O with a 1-sigma, precision of 3.5 ppb and CH4 with a 1-sigma precision of 3ppb on a 5 minute average. The instrument also has extremely low drift to enable accurate measurements with infrequent calibrations. The data rate of the analyzer is on the order of 5 seconds in order to capture fast, episodic emission events. One of the keys to making accurate CRDS measurements is to thoroughly characterize and correct for spectral interfering species. This is especially important for closed system soil chambers used on agricultural soils where a variety of soil amendments may be applied and gases not usually present in ambient air could concentrate to high levels. In this work, we present the results of analyzer interference testing and corrections completed for the interference of carbon dioxide, methane, ammonia, ethane, ethylene, acetylene, and water on N2O. In addition, we will present the results of testing done with the analyzer attached to both closed and open chamber systems to quantify fluxes of N2O and CH4 from active soil samples. The soil samples were collected by the University of Iowa from soil test sites used for studying the application of biochar as a soil amendment. Results will compare the two chamber methodologies and results from several soil sample types, garden, agricultural and natural. Preliminary results from laboratory measurements of soil core samples taken from a garden soil sample using the closed-system chamber method show N2O emission to be on the order of 5.67 x 10-2 μg/cm3*hr, which is in good agreement with the open-system chamber method tested on the same soil sample, which yielded fluxes of 6.01 x 10-2 μg/cm3*hr . Additional work presented will verify these initial results and will be compared to literature such as Hutchinsion and Livingston 1993 assessment of the bias of different chamber flux methodologies.

Cooling of High Pressure Rocket Thrust Chambers with Liquid Oxygen

NASA Technical Reports Server (NTRS)

Price, H. G.

1980-01-01

An experimental program using hydrogen and oxygen as the propellants and supercritical liquid oxygen (LOX) as the coolant was conducted at 4.14 and 8.274 MN/square meters (600 and 1200 psia) chamber pressure. Data on the following are presented: the effect of LOX leaking into the combustion region through small cracks in the chamber wall; and verification of the supercritical oxygen heat transfer correlation developed from heated tube experiments; A total of four thrust chambers with throat diameters of 0.066 m were tested. Of these, three were cyclically tested to 4.14 MN/square meters (600 psia) chamber pressure until a crack developed. One had 23 additional hot cycles accumulated with no apparent metal burning or distress. The fourth chamber was operated at 8.274 MN/square meters (1200 psia) pressure to obtain steady state heat transfer data. Wall temperature measurements confirmed the heat transfer correlation.

Validation of High Aspect Ratio Cooling in a 89 kN (20,000 lb(sub f)) Thrust Combustion Chamber

NASA Technical Reports Server (NTRS)

Wadel, Mary F.; Meyer, Michael L.

1996-01-01

In order to validate the benefits of high aspect ratio cooling channels in a large scale rocket combustion chamber, a high pressure, 89 kN (20,000 lbf) thrust, contoured combustion chamber was tested in the NASA Lewis Research Center Rocket Engine Test Facility. The combustion chamber was tested at chamber pressures from 5.5 to 11.0 MPa (800-1600 psia). The propellants were gaseous hydrogen and liquid oxygen at a nominal mixture ratio of six, and liquid hydrogen was used as the coolant. The combustion chamber was extensively instrumented with 30 backside skin thermocouples, 9 coolant channel rib thermocouples, and 10 coolant channel pressure taps. A total of 29 thermal cycles, each with one second of steady state combustion, were completed on the chamber. For 25 thermal cycles, the coolant mass flow rate was equal to the fuel mass flow rate. During the remaining four thermal cycles, the coolant mass flow rate was progressively reduced by 5, 6, 11, and 20 percent. Computer analysis agreed with coolant channel rib thermocouples within an average of 9 percent and with coolant channel pressure drops within an average of 20 percent. Hot-gas-side wall temperatures of the chamber showed up to 25 percent reduction, in the throat region, over that of a conventionally cooled combustion chamber. Reducing coolant mass flow yielded a reduction of up to 27 percent of the coolant pressure drop from that of a full flow case, while still maintaining up to a 13 percent reduction in a hot-gas-side wall temperature from that of a conventionally cooled combustion chamber.

Optimization of a mist chamber (Cofer scrubber) for sampling water-soluble organics in air.

PubMed

Spaulding, Reggie S; Talbot, Robert W; Charles, M Judith

2002-04-15

While the atmospheric fate and transport of biogenic and anthropogenic hydrocarbons has been extensively studied, little is known about the behavior of first-, second-, and third generation photo-oxidation products that arise from OH radical oxidation of the parent species. The results of chamber experiments establish that *OH oxidation of biogenic and anthropogenic hydrocarbons yields carbonyls, dicarbonyls, hydroxycarbonyls, and keto-acids. However, little is known about the generation and fate of these products in the ambient atmospheric environment. This is changing because of the advent of methods that rely on 0-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine (PFBHA) derivatization of carbonyls in concert with gas chromatography/ion trap mass spectrometry. Such methods provide the means to identify and quantify water-soluble organics, which historically have been difficult to measure. A limitation of existing sampling methods, however, is the use of devices that require low flow rates (0.5-1 L min(-1)). Accordingly, long sampling times (3-4 h) are needed to obtain pptv-ppbv detection limits. The mist chamber is an attractive device because of the high flow rates (25-70 L min(-1)) compatible with its use. Herein, we evaluate a mist chamber using a flow rate of 25-30 L min(-1) to provide short (10 min) sampling times and pptv limits of detection. The results establish a relationship between the Henry's law constant (KH) and the collection efficiency and demonstrate the suitability of the method to measure analytes with KH > or = 10(3) M atm(-1). Adjusting the pH, adding quaternary ammonium salts, or decreasing the temperature of the collecting solution in the mist chamber did not significantly affect the collection efficiency. We tested the method by sampling photooxidation products of isoprene (glyoxal, methylglyoxal, hydroxyacetone, and glycolaldehyde) in the Blodgett Forest, CA. This is the first report of a study the employs the mist chamberto sample hydroxycarbonyls. The accuracy and the reproducibility of the method were evaluated by the analysis of duplicate samples and field spikes. The mean recovery of field spikes was > or =80%, and the relative standard deviation was < or =22% between duplicate measurements. The detection limits were 48, 15, 7.7, and 2.7 pptv for glycolaldehyde, hydroxyacetone, methylglyoxal, and glyoxal, respectively. This work demonstrates the power of the mist chamber in concert with PFBHA derivatization and mass spectrometry to measure pptv concentrations of water-soluble organics with a sampling time of 10 min.

Characterization of Gas Transport Properties of Fractured Rocks By Borehole and Chamber Tests.

NASA Astrophysics Data System (ADS)

Shimo, M.; Shimaya, S.; Maejima, T.

2014-12-01

Gas transport characteristics of fractured rocks is a great concern to variety of engineering applications such as underground storage of LPG, nuclear waste disposal, CCS and gas flooding in the oil field. Besides absolute permeability, relative permeability and capillary pressure as a function of water saturation have direct influences to the results of two phase flow simulation. However, number of the reported gas flow tests for fractured rocks are limited, therefore, the applicability of the conventional two-phase flow functions used for porous media, such as Mualem-van Genuchten model, to prediction of the gas transport in the fractured rock mass are not well understood. The authors conducted the two types of in-situ tests, with different scales, a borehole gas-injection test and a chamber gas-injection test in fractured granitic rock. These tests were conducted in the Cretaceous granitic rocks at the Namikata underground LPG storage cavern construction site in Ehime Prefecture in Japan, preceding to the cavern scale gas-tightness test. A borehole injection test was conducted using vertical and sub-vertical boreholes drilled from the water injection tunnel nearly at the depth of the top of the cavern, EL-150m. A new type downhole gas injection equipment that is capable to create a small 'cavern' within a borehole was developed. After performing a series of preliminary tests to investigate the hydraulic conductivity and gas-tightness, i.e. threshold pressure, gas injection tests were conducted under different gas pressure. Fig.1 shows an example of the test results From a chamber test using a air pressurizing chamber with volume of approximately166m3, the gas-tightness was confirmed within the uncertainty of 22Pa under the storage pressure of 0.7MPa, however, significant air leakage occurred possibly through an open fracture intersecting the chamber just after cavern pressure exceeds the initial hydrostatic pressure at the ceiling level of the chamber. Anomalies were detected in the data of the pore pressure as well as AE monitoring around the chamber. Results from the above two tests were simulated using a multi-phase transport simulator, TOUGH2, developed at Lawrence Berkeley National Laboratory. Fig.2 shows the model and an example of the simulation.

Mechanism Guides Hatch Through Hatchway

NASA Technical Reports Server (NTRS)

Barron, Daniel R.; Kennedy, Steven E.

1993-01-01

Elliptical hatch designed to move through hatchway to make pressure-assisted seal with either side of bulkhead. Compact three-degree-of-freedom mechanism guides hatch through hatchway or holds hatch off to one side to facilitate passage of crew and/or equipment. Hatches and mechanisms used in submarines, pressure chambers (including hyperbaric treatment chambers), vacuum chambers, and vacuum-or-pressure test chambers.

Methods of conducting simultaneous exothermic and endothermic reactions

DOEpatents

Tonkovich, Anna Lee [Marysville, OH; Roberts, Gary L [West Richland, WA; Perry, Steven T [Galloway, OH; Fitzgerald, Sean P [Columbus, OH

2005-11-29

Integrated Combustion Reactors (ICRs) and methods of making ICRs are described in which combustion chambers (or channels) are in direct thermal contact to reaction chambers for an endothermic reaction. Superior results were achieved for combustion chambers which contained a gap for free flow through the chamber. Particular reactor designs are also described. Processes of conducting reactions in integrated combustion reactors are described and results presented. Some of these processes are characterized by unexpected and superior results.

Method and apparatus for obtaining enhanced production rate of thermal chemical reactions

DOEpatents

Tonkovich, Anna Lee Y [Pasco, WA; Wang, Yong [Richland, WA; Wegeng, Robert S [Richland, WA; Gao, Yufei [Kennewick, WA

2003-04-01

The present invention is a method and apparatus (vessel) for providing a heat transfer rate from a reaction chamber through a wall to a heat transfer chamber substantially matching a local heat transfer rate of a catalytic thermal chemical reaction. The key to the invention is a thermal distance defined on a cross sectional plane through the vessel inclusive of a heat transfer chamber, reaction chamber and a wall between the chambers. The cross sectional plane is perpendicular to a bulk flow direction of the reactant stream, and the thermal distance is a distance between a coolest position and a hottest position on the cross sectional plane. The thermal distance is of a length wherein the heat transfer rate from the reaction chamber to the heat transfer chamber substantially matches the local heat transfer rate.

Recirculating Molten Metal Supply System And Method

DOEpatents

Kinosz, Michael J.; Meyer, Thomas N.

2003-07-01

The melter furnace includes a heating chamber (16), a pump chamber (18), a degassing chamber (20), and a filter chamber (22). The pump chamber (18) is located adjacent the heating chamber (16) and houses a molten metal pump (30). The degassing chamber (20) is located adjacent and in fluid communication with the pump chamber (18), and houses a degassing mechanism (36). The filter chamber (22) is located adjacent and in fluid communication with the degassing chamber (20). The filter chamber (22) includes a molten metal filter (38). The melter furnace (12) is used to supply molten metal to an externally located holder furnace (14), which then recirculates molten metal back to the melter furnace (12).

Reproducibility of Dual-Microphone Voice Range Profile Equipment

ERIC Educational Resources Information Center

Printz, Trine; Pedersen, Ellen Raben; Juhl, Peter; Nielsen, Troels; Grøntved, Ågot Møller; Godballe, Christian

2017-01-01

Purpose: The aim of this study was to add further knowledge about the usefulness of the Voice Range Profile (VRP) assessment in clinical settings and research by analyzing VRP dual-microphone equipment precision, reliability, and room effect. Method: Test-retest studies were conducted in an anechoic chamber and an office: (a) comparing sound…

Managing scab diseases of potato and radish caused by Streptomyces spp. using Bacillus amyloliquefaciens BAC03 and other biomaterials

USDA-ARS?s Scientific Manuscript database

Streptomyces spp. cause scab disease in plants like potato and radish. To seek effective control methods of this disease, biologically based materials were examined on their efficacies for disease control. In greenhouse or growth chamber tests, potting soil was infested with Streptomyces scabies (10...

Internal short circuit and accelerated rate calorimetry tests of lithium-ion cells: Considerations for methane-air intrinsic safety and explosion proof/flameproof protection methods.

PubMed

Dubaniewicz, Thomas H; DuCarme, Joseph P

2016-09-01

Researchers with the National Institute for Occupational Safety and Health (NIOSH) studied the potential for lithium-ion cell thermal runaway from an internal short circuit in equipment for use in underground coal mines. In this third phase of the study, researchers compared plastic wedge crush-induced internal short circuit tests of selected lithium-ion cells within methane (CH 4 )-air mixtures with accelerated rate calorimetry tests of similar cells. Plastic wedge crush test results with metal oxide lithium-ion cells extracted from intrinsically safe evaluated equipment were mixed, with one cell model igniting the chamber atmosphere while another cell model did not. The two cells models exhibited different internal short circuit behaviors. A lithium iron phosphate (LiFePO 4 ) cell model was tolerant to crush-induced internal short circuits within CH 4 -air, tested under manufacturer recommended charging conditions. Accelerating rate calorimetry tests with similar cells within a nitrogen purged 353-mL chamber produced ignitions that exceeded explosion proof and flameproof enclosure minimum internal pressure design criteria. Ignition pressures within a 20-L chamber with 6.5% CH 4 -air were relatively low, with much larger head space volume and less adiabatic test conditions. The literature indicates that sizeable lithium thionyl chloride (LiSOCl 2 ) primary (non rechargeable) cell ignitions can be especially violent and toxic. Because ignition of an explosive atmosphere is expected within explosion proof or flameproof enclosures, there is a need to consider the potential for an internal explosive atmosphere ignition in combination with a lithium or lithium-ion battery thermal runaway process, and the resulting effects on the enclosure.

Vapor-barrier Vacuum Isolation System

NASA Technical Reports Server (NTRS)

Weinstein, Leonard M. (Inventor); Taminger, Karen M. (Inventor)

2014-01-01

A system includes a collimated beam source within a vacuum chamber, a condensable barrier gas, cooling material, a pump, and isolation chambers cooled by the cooling material to condense the barrier gas. Pressure levels of each isolation chamber are substantially greater than in the vacuum chamber. Coaxially-aligned orifices connect a working chamber, the isolation chambers, and the vacuum chamber. The pump evacuates uncondensed barrier gas. The barrier gas blocks entry of atmospheric vapor from the working chamber into the isolation chambers, and undergoes supersonic flow expansion upon entering each isolation chamber. A method includes connecting the isolation chambers to the vacuum chamber, directing vapor to a boundary with the working chamber, and supersonically expanding the vapor as it enters the isolation chambers via the orifices. The vapor condenses in each isolation chamber using the cooling material, and uncondensed vapor is pumped out of the isolation chambers via the pump.

Outgassing measurement of the aluminum alloy UHV chamber

NASA Technical Reports Server (NTRS)

Miyamoto, M.; Itoh, T.; Komaki, S.; Narushima, K.; Ishimaru, H.

1986-01-01

A large vacuum chamber (580 mm diameter) was fabricated from an aluminum alloy surface treated by a special process normally used on small chambers. The chamber was tested unbaked and baked at various temperatures, pressures, and holding periods. The chamber was filled with N2 gas, and the outgassing rate was measured after one hour. Then the ultimate pressure was measured. Outgassing rates for baked and unbaked groups were compared. It is concluded that the same surface treatment technique can be used on both large and small chambers produced by the same special extrusion process.

New central drift chamber for the MARK II at SLC

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

Bartelt, J.E.

A new central drift chamber has been constructed for the Mark II detector for use at the new SLAC Linear Collider (SLC). The design of the chamber is based on a multi-sense-wire cell of the jet chamber type. In addition to drift-time measurements, pulse-height measurements from the sense wires provide electron-hadron separation by dE/dx. The chamber has been tested in operation at PEP before its move to the SLC. The design and construction are described, and measurements from the new chamber are presented.

Methods and apparatus for the on-site production of hydrogen peroxide

NASA Technical Reports Server (NTRS)

Buschmann, Wayne E. (Inventor); James, Patrick I. (Inventor)

2010-01-01

Methods, apparatus, and applications for the on-site production of hydrogen peroxide are described. An embodiment of the apparatus comprises at least one anolyte chamber coupled to at least one anode, at least one catholyte chamber, wherein the at least one catholyte chamber is coupled to at least one cathode, at least one anode membrane and at least one cathode membrane, wherein the anode membrane is adjacent to the at least one anode, wherein the cathode membrane is adjacent to the at least one cathode, at least one central chamber disposed between the at least one anolyte chamber and the at least one catholyte chamber. Hydrogen peroxide is produced by reduction of an oxygen-containing gas at the cathode.

Device and method for automated separation of a sample of whole blood into aliquots

DOEpatents

Burtis, Carl A.; Johnson, Wayne F.

1989-01-01

A device and a method for automated processing and separation of an unmeasured sample of whole blood into multiple aliquots of plasma. Capillaries are radially oriented on a rotor, with the rotor defining a sample chamber, transfer channels, overflow chamber, overflow channel, vent channel, cell chambers, and processing chambers. A sample of whole blood is placed in the sample chamber, and when the rotor is rotated, the blood moves outward through the transfer channels to the processing chambers where the blood is centrifugally separated into a solid cellular component and a liquid plasma component. When the rotor speed is decreased, the plasma component backfills the capillaries resulting in uniform aliquots of plasma which may be used for subsequent analytical procedures.

An overview of changes in pressure values of the middle ear using impedance audiometry among diver candidates in a hyperbaric chamber before and after a pressure test

NASA Astrophysics Data System (ADS)

Anoraga, J. S.; Bramantyo, B.; Bardosono, S.; Simanungkalit, S. H.; Basiruddin, J.

2017-08-01

Impedance audiometry is not yet routinely used in pressure tests, especially in Indonesia. Direct exposure to pressure in a hyperbaric chamber is sometimes without any assessment of the middle ear or the Eustachian tube function (ETF) of ventilation. Impedance audiometry examinations are important to assess ETF ventilation. This study determined the middle ear pressure value changes associated with the ETF (ventilation) of prospective divers. This study included 29 prospective divers aged 20-40 years without conductive hearing loss. All subjects underwent a modified diving impedance audiometry examination both before and after the pressure test in a double-lock hyperbaric chamber. Using the Toynbee maneuver, the values obtained for changes of pressure in the middle ear were significant before and after the pressure test in the right and left ears: p < 0.001 and p = 0.018, respectively. The impedance audiometry examination is necessary for the selection of candidate divers undergoing pressure tests within a hyperbaric chamber.

Chambers versus Relaxed Eddy Accumulation: an intercomparison study of two methods for short-term measurements of biogenic CO2 fluxes

NASA Astrophysics Data System (ADS)

Jasek, Alina; Zimnoch, Miroslaw; Gorczyca, Zbigniew; Chmura, Lukasz; Necki, Jaroslaw

2014-05-01

The presented work is a part of comprehensive study aimed at thorough characterization of carbon cycle in the urban environment of Krakow, southern Poland. In the framework of this study two independent methods were employed to quantify biogenic CO2 flux in the city: (i) closed chambers, and (ii) Relaxed Eddy Accumulation (REA). The results of a three-day intensive intercomparison campaign performed in July 2013 and utilizing both measurement methods are reported here. The chamber method is a widely used approach for measurements of gas exchange between the soil and the atmosphere. The system implemented in this study consisted of a single chamber operating in a closed-dynamic mode, combined with Vaisala CarboCAP infrared CO2 sensor in a mobile setup. An alternative flux measurement method, covering larger area is represented by REA, which is a modification of the eddy covariance method. It consists of a 3D anemometer (Gill Windmaster Pro) and the system collecting updraft and downdraft samples to 5-litre Tedlar bags. The CO2 mixing ratios in the collected samples are measured by Picarro G2101i analyzer. The setup consists of two sets of bags so that the sampling can be performed continuously with 15-min temporal resolution. A 48-hectares open meadow located close the city center was chosen as a test site for comparison of the two methods of CO2 flux measurements outlined above. In the middle of the meadow a 3-metre high tripod was installed with the anemometer and REA inlet system. For a period of 46 hours the system was measuring net CO2 flux from the surrounding area. A meteorological conditions and intensity of photosynthetically active radiation (PAR) were also recorded. In the same time, CO2 flux from several points around the REA inlet was measured with the chamber system, resulting in 93 values for both respiration and net CO2 flux. Chamber results show rather homogenous distribution of the soil CO2 flux (the mean value equal to 40.9 ± 2.2 mmol/m2h), with slight increase towards the city centre. Good agreement between the two measurement methods was obtained, with night-time flux ranging from around 10 to 80 mmol/m2h and day-time net flux reaching -88 mmol/m2h at peak PAR intensity. Positive correlation between the net CO2 flux and intensity of PAR was also observed. Acknowledgements: The study was supported by the Ministry of Science and Higher Education (817.N-COST/2010/0) and the statutory funds of the AGH University of Science and Technology (11.11.220.01).

Process of electrolysis and fractional crystallization for aluminum purification

DOEpatents

Dawless, R.K.; Bowman, K.A.; Mazgaj, R.M.; Cochran, C.N.

1983-10-25

A method is described for purifying aluminum that contains impurities, the method including the step of introducing such aluminum containing impurities to a charging and melting chamber located in an electrolytic cell of the type having a porous diaphragm permeable by the electrolyte of the cell and impermeable to molten aluminum. The method includes further the steps of supplying impure aluminum from the chamber to the anode area of the cell and electrolytically transferring aluminum from the anode area to the cathode through the diaphragm while leaving impurities in the anode area, thereby purifying the aluminum introduced into the chamber. The method includes the further steps of collecting the purified aluminum at the cathode, and lowering the level of impurities concentrated in the anode area by subjecting molten aluminum and impurities in said chamber to a fractional crystallization treatment wherein eutectic-type impurities crystallize and precipitate out of the aluminum. The eutectic impurities that have crystallized are physically removed from the chamber. The aluminum in the chamber is now suited for further purification as provided in the above step of electrolytically transferring aluminum through the diaphragm. 2 figs.

Process of electrolysis and fractional crystallization for aluminum purification

DOEpatents

Dawless, Robert K.; Bowman, Kenneth A.; Mazgaj, Robert M.; Cochran, C. Norman

1983-10-25

A method for purifying aluminum that contains impurities, the method including the step of introducing such aluminum containing impurities to a charging and melting chamber located in an electrolytic cell of the type having a porous diaphragm permeable by the electrolyte of the cell and impermeable to molten aluminum. The method includes further the steps of supplying impure aluminum from the chamber to the anode area of the cell and electrolytically transferring aluminum from the anode area to the cathode through the diaphragm while leaving impurities in the anode area, thereby purifying the aluminum introduced into the chamber. The method includes the further steps of collecting the purified aluminum at the cathode, and lowering the level of impurities concentrated in the anode area by subjecting molten aluminum and impurities in said chamber to a fractional crystallization treatment wherein eutectic-type impurities crystallize and precipitate out of the aluminum. The eutectic impurities that have crystallized are physically removed from the chamber. The aluminum in the chamber is now suited for further purification as provided in the above step of electrolytically transferring aluminum through the diaphragm.

Advanced small rocket chambers: Option 1, 14 lbf Ir-Re rocket

NASA Technical Reports Server (NTRS)

Jassowski, Donald M.; Gage, Mark L.

1992-01-01

A high performance Ir-Re 14 lbf (62 N) chamber and nozzle which can be a direct replacement for a production engine was designed, built, hot fired and vibration acceptance tested. It passed all acceptance tests satisfactorily and demonstrated a 20 sec increase in specific impulse (Is) over the conventional 14 lbf silicide coated Cb chamber. The high performance engine uses the production valve and injector without modification. Incorporation of a secondary mixing device or Boundary Layer Trip within the combustion chamber results in elimination of the fuel film coolant, improvement in flow uniformity, the 20 sec performance increase, and reduction of a potential source of spacecraft contamination. Measured Is was 305 sec at 75:1 area ratio, with monomenthylhydrazine and nitrogen tetroxide propellants. Qualification tests remain to be done.

13-Foot Diameter Hydrogen Tank Tested in the K-Site Test Chamber

NASA Image and Video Library

1967-09-21

A 13-foot diameter mounted inside the large test chamber at the Cryogenic Propellant Tank, or K-Site, at National Aeronautics and Space Administration’s (NASA) Plum Brook Station. The 25-foot test chamber and 20-foot access door were designed to test liquid hydrogen fuel tanks up to 18 feet in diameter in conditions that simulated launches and spaceflight. Shakers were installed to test the effects of launch vibration on the tanks and their insulation. The K Site chamber was also equipped with cold walls that could be cooled with either liquid nitrogen or liquid hydrogen and vacuum pumps that could reduce pressure levels to 10-8 torr. This 13-foot tank passed its initial acceptance tests in K-Site on August 24, 1966. Delays in the modification of the tank postponed further tests of the tank until May 1967. Four pressure hold tests and expulsion runs were made in May using gaseous hydrogen or gaseous helium at 300R and 520R. In June a straight pipe injector test was run and two pressure effect tests at 35 and 75psi. Propellant slosh tests were successfully run in August. This photograph was taken the day after the program’s final runs on September 12, 1967.

Quantifying evapotranspiration from urban green roofs: a comparison of chamber measurements with commonly used predictive methods.

PubMed

Marasco, Daniel E; Hunter, Betsy N; Culligan, Patricia J; Gaffin, Stuart R; McGillis, Wade R

2014-09-02

Quantifying green roof evapotranspiration (ET) in urban climates is important for assessing environmental benefits, including stormwater runoff attenuation and urban heat island mitigation. In this study, a dynamic chamber method was developed to quantify ET on two extensive green roofs located in New York City, NY. Hourly chamber measurements taken from July 2009 to December 2009 and April 2012 to October 2013 illustrate both diurnal and seasonal variations in ET. Observed monthly total ET depth ranged from 0.22 cm in winter to 15.36 cm in summer. Chamber results were compared to two predictive methods for estimating ET; namely the Penman-based ASCE Standardized Reference Evapotranspiration (ASCE RET) equation, and an energy balance model, both parametrized using on-site environmental conditions. Dynamic chamber ET results were similar to ASCE RET estimates; however, the ASCE RET equation overestimated bottommost ET values during the winter months, and underestimated peak ET values during the summer months. The energy balance method was shown to underestimate ET compared the ASCE RET equation. The work highlights the utility of the chamber method for quantifying green roof evapotranspiration and indicates green roof ET might be better estimated by Penman-based evapotranspiration equations than energy balance methods.

James Webb Space Telescope in NASA's giant thermal vacuum chamber

NASA Image and Video Library

2015-04-20

Inside NASA's giant thermal vacuum chamber, called Chamber A, at NASA's Johnson Space Center in Houston, the James Webb Space Telescope's Pathfinder backplane test model, is being prepared for its cryogenic test. Previously used for manned spaceflight missions, this historic chamber is now filled with engineers and technicians preparing for a crucial test. Exelis developed and installed the optical test equipment in the chamber. "The optical test equipment was developed and installed in the chamber by Exelis," said Thomas Scorse, Exelis JWST Program Manager. "The Pathfinder telescope gives us our first opportunity for an end-to-end checkout of our equipment." "This will be the first time on the program that we will be aligning two primary mirror segments together," said Lee Feinberg, NASA Optical Telescope Element Manager. "In the past, we have always tested one mirror at a time but this time we will use a single test system and align both mirrors to it as though they are a single monolithic mirror." The James Webb Space Telescope is the scientific successor to NASA's Hubble Space Telescope. It will be the most powerful space telescope ever built. Webb is an international project led by NASA with its partners, the European Space Agency and the Canadian Space Agency. Image credit: NASA/Chris Gunn Text credit: Laura Betz, NASA's Goddard Space Flight Center, Greenbelt, Maryland NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Tracking chamber made of 15-mm mylar drift tubes

NASA Astrophysics Data System (ADS)

Kozhin, A.; Borisov, A.; Bozhko, N.; Fakhrutdinov, R.; Plotnikov, I.

2017-05-01

We are presenting a drift chamber composed from three layers of mylar drift tubes with outer diameter 15 mm. The pipe is made of strip of mylar film 125 micrometers thick covered with aluminium from the both sides. A strip of mylar is wrapped around the mandrel. Pipe is created by ultrasonic welding. A single drift tube is self-supported structure withstanding 350 g wire tension without supports and internal overpressure. About 400 such tubes were assembled. Design, quality control procedures of the drift tubes are described. Seven chambers were glued from these tubes of 560 mm length. Each chamber consists of 3 layers, 16 tubes per layer. Several chambers were tested with cosmic rays. Results of the tests, counting rate plateau and coordinate resolution are presented.

Testing and evaluation of oxide-coated iridium/rhenium chambers

NASA Technical Reports Server (NTRS)

Reed, Brian D.

1993-01-01

Iridium-coated rhenium provides long life operation of radiation-cooled rockets at temperatures up to 2200 C. Ceramic oxide coatings could be used to increase iridium/rhenium rocket lifetimes and allow operation in highly oxidizing environments. Ceramic oxide coatings promise to serve as both thermal and diffusion barriers for the iridium layer. Seven ceramic oxide-coated iridium/rhenium, 22 N rocket chambers were tested on gaseous hydrogen/gaseous oxygen propellants. Five chambers had thick (over 10 mils), monolithic coatings of either hafnia or zirconia. Two chambers had coatings with thicknesses less than 5 mils. One of these chambers had a thin-walled coating of zirconia infiltrated with sol gel hafnia. The other chamber had a coating composed of an iridium/oxide composite. The purpose of this test program was to assess the ability of the oxide coatings to withstand the thermal shock of combustion initiation, adhere under repeated thermal cycling, and operate in aggressively oxidizing environments. All of the coatings survived the thermal shock of combustion and demonstrated operation at mixture ratios up to 11. The iridium/oxide composite coated chamber included testing for over 29 minutes at mixture ratio 16. The thicker-walled coatings provided the larger temperature drops across the oxide layer (up to 570 C), but were susceptible to macrocracking and eventual chipping at a stress concentrator. The cracks apparently resealed during firing, under compression of the oxide layer. The thinner-walled coatings did not experience the macrocracking and chipping of the chambers seen with the thick, monolithic coatings. However, burnthroughs in the throat region did occur in both of the thin-walled chambers at mixture ratios well above stochiometric. The burn-throughs were probably the result of oxygen-diffusion through the oxide coating that allowed the underlying iridium and rhenium layers to be oxidized. The results of this test program indicated that the thin-walled oxide coatings are better suited for repeated thermal cycling than the thick-walled coating, while thicker coatings may be required for operation in aggressively oxidizing environments.

Johnson Space Center's Regenerative Life Support Systems Test Bed

NASA Technical Reports Server (NTRS)

Barta, D. J.; Henninger, D. L.

1996-01-01

The Regenerative Life Support Systems (RLSS) Test Bed at NASA's Johnson Space Center is an atmospherically closed, controlled environment facility for human testing of regenerative life support systems using higher plants in conjunction with physicochemical life support systems. The facility supports NASA's Advanced Life Support (ALS) Program. The facility is comprised of two large scale plant growth chambers, each with approximately 11 m2 growing area. The root zone in each chamber is configurable for hydroponic or solid media plant culture systems. One of the two chambers, the Variable Pressure Growth Chamber (VPGC), is capable of operating at lower atmospheric pressures to evaluate a range of environments that may be used in a planetary surface habitat; the other chamber, the Ambient Pressure Growth Chamber (APGC) operates at ambient atmospheric pressure. The air lock of the VPGC is currently being outfitted for short duration (1 to 15 day) human habitation at ambient pressures. Testing with and without human subjects will focus on 1) integration of biological and physicochemical air and water revitalization systems; 2) effect of atmospheric pressure on system performance; 3) planetary resource utilization for ALS systems, in which solid substrates (simulated planetary soils or manufactured soils) are used in selected crop growth studies; 4) environmental microbiology and toxicology; 5) monitoring and control strategies; and 6) plant growth systems design. Included are descriptions of the overall design of the test facility, including discussions of the atmospheric conditioning, thermal control, lighting, and nutrient delivery systems.

Johnson Space Center's Regenerative Life Support Systems Test Bed

NASA Astrophysics Data System (ADS)

Barta, D. J.; Henninger, D. L.

1996-01-01

The Regenerative Life Support Systems (RLSS) Test Bed at NASA's Johnson Space Center is an atmospherically closed, controlled environment facility for human testing of regenerative life support systems using higher plants in conjunction with physicochemical life support systems. The facility supports NASA's Advanced Life Support (ALS) Program. The facility is comprised of two large scale plant growth chambers, each with approximately 11 m^2 growing area. The root zone in each chamber is configurable for hydroponic or solid media plant culture systems. One of the two chambers, the Variable Pressure Growth Chamber (VPGC), is capable of operating at lower atmospheric pressures to evaluate a range of environments that may be used in a planetary surface habitat; the other chamber, the Ambient Pressure Growth Chamber (APGC) operates at ambient atmospheric pressure. The air lock of the VPGC is currently being outfitted for short duration (1 to 15 day) human habitation at ambient pressures. Testing with and without human subjects will focus on 1) integration of biological and physicochemical air and water revitalization systems; 2) effect of atmospheric pressure on system performance; 3) planetary resource utilization for ALS systems, in which solid substrates (simulated planetary soils or manufactured soils) are used in selected crop growth studies; 4) environmental microbiology and toxicology; 5) monitoring and control strategies; and 6) plant growth systems design. Included are descriptions of the overall design of the test facility, including discussions of the atmospheric conditioning, thermal control, lighting, and nutrient delivery systems.

EVALUATING SOURCES OF INDOOR AIR POLLUTION

EPA Science Inventory

The article discusses a three-phase approach, employing environmental chambers, indoor air quality (IAQ) models, and test house experiments, that is effective in linking sources of indoor pollutants to measured concentrations. mission factors developed in test chambers can be use...

Histological Study of the Toxic Effects of Solder Fumes on Spermatogenesis in Rats

PubMed Central

Arab, Mohammad Reza; Heidari, Mohammad Hossein; Mashhadi, Rezvaneh; Mirzaei, Ramazan; Jahantigh, Mehdi

2011-01-01

Objective: Toxic fumes generated during the soldering process contain various contaminants released at sufficient rates to cause both short- and long-term health problems. Studies have shown that these fumes change the quality and quantity of semen fluid in exposed workers. The aim of the present study was to determine the potentially toxic effects of solder fumes on spermatogenesis in seminiferous tubules of rats as an experimental model, with conditioned media in an exposed chamber. Materials and Methods: A total number of 48 male Sprague Dawley adult rats were randomly divided into experimental (n=30) and control (n=18) groups. Based on exposure time, each group was further subdivided into two, four and six subgroups. Rats in the experimental groups were exposed to solder fumes in an exposure chamber for one hour/ day. The concentrations of fumes [formaldehyde, stanum (Sn) and lead (Pb)] were measured by a standard method via atomic absorption and spectrophotometry. According to a timetable, under deep anesthesia, the rats of both experimental and control subgroups were killed. After fixation of testes, specimens were weighed and routinely processed. Paraffin sections were stained by hematoxylin and eosin. Spermiogenesis index was calculated and data analyzed by Mann Whitney NPAR test. Results: Analysis of air samples in the exposure chamber showed the following fume concentrations: 0.193 mg/m3 for formaldehyde, 0.35 mg/m3 for Sn and 3 mg/m3 for Pb. Although there was no significant difference in testes weight between control and experimental subgroups, there was only a significant difference in spermiogenesis index between the six week experimental and control subgroups (p<0.02). Conclusion: The results of this study showed that solder fumes can change the spermiogenesis index in experimental groups in a time dependent manner. PMID:23671821

Heat exchanger and method of making. [bonding rocket chambers with a porous metal matrix

NASA Technical Reports Server (NTRS)

Fortini, A.; Kazaroff, J. M. (Inventor)

1978-01-01

A heat exchanger of increased effectiveness is disclosed. A porous metal matrix is disposed in a metal chamber or between walls through which a heat-transfer fluid is directed. The porous metal matrix has internal bonds and is bonded to the chamber in order to remove all thermal contact resistance within the composite structure. Utilization of the invention in a rocket chamber is disclosed as a specific use. Also disclosed is a method of constructing the heat exchanger.

Inert gas ion thruster

NASA Technical Reports Server (NTRS)

Ramsey, W. D.

1980-01-01

Inert gas performance with three types of 12 cm diameter magnetoelectrostatic containment (MESC) ion thrusters was tested. The types tested included: (1) a hemispherical shaped discharge chamber with platinum cobalt magnets; (2) three different lengths of the hemispherical chambers with samarium cobalt magnets; and (3) three lengths of the conical shaped chambers with aluminum nickel cobalt magnets. The best argon performance was produced by a 8.0 cm long conical chamber with alnico magnets. The best xenon high mass utilization performance was obtained with the same 8.0 cm long conical thruster. The hemispherical thruster obtained 75 to 87% mass utilization at 185 to 205 eV/ion of singly charged ion equivalent beam.

Apparatus for adjusting and maintaining the humidity of gas at a constant value within a closed system

DOEpatents

Abernathy, Bethel R.; Walters, Ronald R.

1986-01-01

The humidity of a gas within a closed system is maintained at constant level by providing a saturated salt solution within a lower chamber in communication with an upper chamber conjointly defined by upper and lower container sections in sealing contact with each other to establish a closed container. A partition wall separates the salt solution from the test region in the upper chamber. A tube extending through the partition plate allows humidified gas to pass from the lower to the upper chamber. A glass wool plug or membranous material within the tube prevents migration of salt into the test region.

Apparatus for adjusting and maintaining the humidity of gas at a constant value within a closed system

DOEpatents

Abernathy, B.R.; Walters, R.R.

1985-08-05

The humidity of a gas within a closed system is maintained at constant level by providing a saturated salt solution within a lower chamber in communication with an upper chamber conjointly defined by upper and lower container sections in sealing contact with each other to establish a closed container. A partition wall separates the salt solution from the test region in the upper chamber. A tube extending through the partition plate allows humidified gas to pass from the lower to the upper chamber. A glass wool plug or membranous material within the tube prevents migration of salt into the test region.

Hydrogen-oxygen auxiliary propulsion for the space shuttle. Volume 2: Low pressure thrusters

NASA Technical Reports Server (NTRS)

1973-01-01

An abbreviated program was conducted to investigate igniter, injector, and thrust chamber technology for a 10.3 N/cm2 (15 psia) chamber pressure, 6660 N (1500 lbf) gaseous H2/O2 APS thruster for the Space Shuttle Vehicle. Successful catalytic igniter tests were conducted with ambient and cold propellants. Injector testing with a heat sink chamber (MR = 2.5, area ratio = 5.0) gave a measured specific impulse of 386 sec with 11% of the fuel used as film coolant. This coolant flow rate was demonstrated to be more than adequate to cool a spun adiabatic wall, flightweight thrust chamber.

Method of retrieving a liquid sample, a suction lysimeter, a portable suction lysimeter, a lysimeter system, and a deep lysimeter

DOEpatents

Hubbell, Joel M.; Sisson, James B.

2003-08-26

A method of retrieving a liquid sample comprises providing a portable lysimeter including a semi-permeable membrane and a chamber in fluid communication with the semi-permeable membrane; making a hole at a site from which a liquid sample is desired; evacuating the chamber by applying a vacuum to the chamber; lowering the portable lysimeter into the hole; obtaining a sample in the chamber; and retrieving the lysimeter from the bore; wherein it is not necessary to backfill the bore. A portable lysimeter includes a semi-permeable member and a chamber in fluid communication with the semi-permeable membrane.

On the anomalies in single-jet hover suckdown data

NASA Technical Reports Server (NTRS)

Kuhn, Richard E.; Bellavia, David C.; Wardwell, Douglas A.; Corsiglia, Victor R.

1991-01-01

The data from nine different investigations of the suckdown induced in ground effect by a single jet issuing from plates of various sizes and shapes have been examined and compared. The results show that the generally accepted method for estimating suckdown significantly underestimated the suckdown for most of the configurations. The study identified several factors that could contribute to the differences. These include ground board size, plate edge effects, jet flow quality, jet impingement angle, the size of the chamber in which the tests were run, and obstructions in the region above the model. Most of these factors have not been investigated and in many cases items such as the size of the test chamber, jet flow quality, ground board size, etc., have not even been shown in the documents reporting the investigation. A program to investigate the effects of these factors is recommended.

Selected papers in the hydrologic sciences 1984; July 1984

USGS Publications Warehouse

Meyer, Eric L.

1984-01-01

The rapid, accurate measurement of the oxygen content of soil gas in the unsaturated zone or dissolved oxygen in soil water in the saturated zone can be useful in wetland vegetation studies. A method has been devised and tested in the Great Dismal Swamp, a wetland with fine silt-clay and organic soils, that appears to provide good results. A 60-milliliter sample of soil gas or water is withdrawn from permanently installed chambers at various depths in the soil profile. The oxygen concentration of air samples is measured with a specially constructed analyzer cell fitted to the polarographic oxygen electrode of a portable oxygen meter. The dissolved oxygen concentration of water samples is measured directly with the oxygen electrode while stirring the sample in a 32-milliliter glass bottle with a portable magnetic stirrer. Field tests with duplicate chamber installations showed that consistent results are obtained for soil gas and water.

Testing fireproof materials in a combustion chamber

NASA Astrophysics Data System (ADS)

Kulhavy, Petr; Martinec, Tomas; Novak, Ondrej; Petru, Michal; Srb, Pavel

This article deals with a prototype concept, real experiment and numerical simulation of a combustion chamber, designed for testing fire resistance some new insulating composite materials. This concept of a device used for testing various materials, providing possibility of monitoring temperatures during controlled gas combustion. As a fuel for the combustion process propane butane mixture has been used and also several kinds of burners with various conditions of inlet air (forced, free) and fuel flows were tested. The tested samples were layered sandwich materials based on various materials or foams, used as fillers in fire shutters. The temperature distribution was measured by using thermocouples. A simulation of whole concept of experimental chamber has been carried out as the non-premixed combustion process in the commercial final volume sw Pyrosim. The result was to design chamber with a construction suitable, according to the international standards, achieve the required values (temperature in time). Model of the combustion based on a stoichiometric defined mixture of gas and the tested layered samples showed good conformity with experimental results - i.e. thermal distribution inside and heat release rate that has gone through the sample.

A Vibration Isolation System for Use in a Large Thermal Vacuum Test Facility

NASA Technical Reports Server (NTRS)

Hershfeld, Donald; VanCampen, Julie

2002-01-01

A thermal vacuum payload platform that is isolated from background vibration is required to support the development of future instruments for Hubble Space Telescope (HST) and the Next Generation Space Telescope (NGST) at the Goddard Space Flight Center (GSFC). Because of the size and weight of the thermal/vacuum facility in which the instruments are tested, it is not practical to isolate the entire facility externally. Therefore, a vibration isolation system has been designed and fabricated to be installed inside the chamber. The isolation system provides a payload interface of 3.05 m (10 feet) in diameter and is capable of supporting a maximum payload weight of 4536 kg (10,000 Lbs). A counterweight system has been included to insure stability of payloads having high centers of gravity. The vibration isolation system poses a potential problem in that leakage into the chamber could compromise the ability to maintain vacuum. Strict specifications were imposed on the isolation system design to minimize leakage. Vibration measurements, obtained inside the chamber, prior to installing the vibration isolation system, indicated levels in all axes of approximately 1 milli-g at about 20 Hz. The vibration isolation system was designed to provide a minimum attenuation of 40 dB to these levels. This paper describes the design and testing of this unique vibration isolation system. Problems with leakage and corrective methods are presented. Isolation performance results are also presented.

Improving the performance and emission characteristics of a single cylinder diesel engine having reentrant combustion chamber using diesel and Jatropha methyl esters.

PubMed

Premnath, S; Devaradjane, G

2015-11-01

The emissions from the Compression ignition (CI) engines introduce toxicity to the atmosphere. The undesirable carbon deposits from these engines are realized in the nearby static or dynamic systems such as vehicles, inhabitants, etc. The objective of this research work is to improve the performance and emission characteristics of a diesel engine in the modified re-entrant combustion chamber using a diesel and Jatropha methyl ester blend (J20) at three different injection pressures. From the literature, it is revealed that the shape of the combustion chamber and the fuel injection pressure have an impact on the performance and emission parameters of the CI engine. In this work, a re-entrant combustion chamber with three different fuel injection pressures (200, 220 and 240bars) has been used in the place of the conventional hemispherical combustion chamber for diesel and J20. From the experimental results, it is found that the re-entrant chamber improves the brake thermal efficiency of diesel and J20 in all the tested conditions. It is also found that the 20% blend of Jatropha methyl ester showed 4% improvement in the brake thermal efficiency in the re-entrant chamber at the maximum injection pressure. Environmental safety directly relates to the reduction in the undesirable effects on both living and non-living things. Currently environmental pollution is of major concern. Even with the stringent emission norms new methods are required to reduce the harmful effects from automobiles. The toxicity of carbon monoxide (CO) is well known. In the re-entrant combustion chamber, the amount of CO emission is reduced by 26% when compared with the conventional fuel operation of the engine. Moreover, the amount of smoke is reduced by 24% and hydrocarbons (HC) emission by 24%. Thus, the modified re-entrant combustion chamber reduces harmful pollutants such as unburned HC and CO as well as toxic smoke emissions. Copyright © 2015 Elsevier Inc. All rights reserved.

Carbon deposition model for oxygen-hydrocarbon combustion, volume 1

NASA Technical Reports Server (NTRS)

Hernandez, R.; Ito, J. I.; Niiya, K. Y.

1987-01-01

Presented are details of the design, fabrication, and testing of subscale hardware used in the evaluation of carbon deposition characteristics of liquid oxygen and three hydrocarbon fuels for both main chamber and preburner/gas generator operating conditions. In main chamber conditions, the deposition of carbon on the combustion chamber wall was investigated at mixture ratios of 2.0 to 4.0 and at pressures of 1000 to 1500 psia. No carbon deposition on the chamber walls was detected at these main chamber mixture ratios. In preburner/gas generator operating conditions, the deposition of carbon on the turbine simulator tubes was evaluated at mixture ratios of 0.20 to 0.60 and at chamber pressures of 720 to 1650 psia. The results of the tests showed carbon deposition rate to be a strong function of mixture ratio and a weak function of chamber pressure. Further analyses evaluated the operational consequences of carbon deposition on preburner/gas generator performance. The report is in two volumes, of which this is Volume 1 covering the main body of the report plus Appendixes A through D.

Skylab 4 crew at start of high altitude chamber test at KSC

NASA Technical Reports Server (NTRS)

1973-01-01

Astronaut Gerald P. Carr, fully suited, Skylab 4 commander, prepares to enter spacecraft 118 (the Skylab 4 vehicle) at the start of the high altitude chamber test at the Kennedy Space Center (KSC) (34093); The Skylab 4 crew, fully suited, are seated inside their Command Module, which has been undergoing high altitude chamber test runs at KSC after being considered as a possible rescue vehicle, if needed for the Skylab 3 crew. Facing the camera is Scientist-Astronaut Edward G. Gibson, science pilot. Astronauts Carr, commander; and William R. Pogue, pilot, are also pictured (34094).

Liquid-hydrogen rocket engine development at Aerojet, 1944 - 1950

NASA Technical Reports Server (NTRS)

Osborn, G. H.; Gordon, R.; Coplen, H. L.; James, G. S.

1977-01-01

This program demonstrated the feasibility of virtually all the components in present-day, high-energy, liquid-rocket engines. Transpiration and film-cooled thrust chambers were successfully operated. The first liquid-hydrogen tests of the coaxial injector was conducted and the first pump to successfully produce high pressures in pumping liquid hydrogen was tested. A 1,000-lb-thrust gaseous propellant and a 3,000-lb-thrust liquid-propellant thrust chamber were operated satisfactorily. Also, the first tests were conducted to evaluate the effects of jet overexpansion and separation on performance of rocket thrust chambers with hydrogen-oxygen propellants.

PALEOBIOLOGICAL APPLICATIONS OF THREE-DIMENSIONAL BIOMETRY ON LARGER BENTHIC FORAMINIFERA: A NEW ROUTE OF DISCOVERIES

PubMed Central

Briguglio, Antonino; Hohenegger, Johann; Less, György

2015-01-01

Four specimens of larger benthic foraminifera (the Recent Palaeonummulites venosus and Operculina ammonoides, and the phylogenetically related Paleogene Nummulites fabianii and N. fichteli) were investigated by X-ray tomography. The resulting three-dimensional measurements enabled a comprehensive, quantitative study of shell morphology to interpret cell growth without specific shell preparation and/or destruction. After segmentation and extraction of all scanned lumina, the following characters were measured on all chambers of each specimen: chamber volume, septal distance, chamber height, and chamber width. The sequence of chamber lumina follows either a logistic function (Palaeonummulites, Operculina), where the deceleration in growth rate of the latest chambers could mark the onset of reproduction, or it can be modeled by a series of stepwise functions with differing constants (Nummulites). Variations around the growth model are either periodic, following external cycles, or random as expressed by abrupt deviations. Therefore, they may reflect the response of the cell to environmental changes in terms of cyclic changes (e.g., seasonality) or single events (e.g., predator attack). Correlations between chamber volume and the other chamber parameters show that septal distance always matches the sequence in chamber volume and can therefore be used as a proxy for environmental analyses in both growth models. Chamber height and width often remain constant around their function and rarely deviate drastically to accommodate the needed lumen for retaining test size and shape. Chamber width may vary according to chamber volume in involute specimens, whereas both chamber height and width correlate with volume in those tests following an Archimedean spiral. X-ray-tomography shows particular promise in determining which parameters that can be assessed routinely in two dimensions primarily reflect environmental conditions vs. parameters best used for taxonomic identification and for systematic lineage reconstruction. PMID:26166915

PALEOBIOLOGICAL APPLICATIONS OF THREE-DIMENSIONAL BIOMETRY ON LARGER BENTHIC FORAMINIFERA: A NEW ROUTE OF DISCOVERIES.

PubMed

Briguglio, Antonino; Hohenegger, Johann; Less, György

2013-01-01

Four specimens of larger benthic foraminifera (the Recent Palaeonummulites venosus and Operculina ammonoides , and the phylogenetically related Paleogene Nummulites fabianii and N. fichteli ) were investigated by X-ray tomography. The resulting three-dimensional measurements enabled a comprehensive, quantitative study of shell morphology to interpret cell growth without specific shell preparation and/or destruction. After segmentation and extraction of all scanned lumina, the following characters were measured on all chambers of each specimen: chamber volume, septal distance, chamber height, and chamber width. The sequence of chamber lumina follows either a logistic function ( Palaeonummulites , Operculina ), where the deceleration in growth rate of the latest chambers could mark the onset of reproduction, or it can be modeled by a series of stepwise functions with differing constants ( Nummulites ). Variations around the growth model are either periodic, following external cycles, or random as expressed by abrupt deviations. Therefore, they may reflect the response of the cell to environmental changes in terms of cyclic changes (e.g., seasonality) or single events (e.g., predator attack). Correlations between chamber volume and the other chamber parameters show that septal distance always matches the sequence in chamber volume and can therefore be used as a proxy for environmental analyses in both growth models. Chamber height and width often remain constant around their function and rarely deviate drastically to accommodate the needed lumen for retaining test size and shape. Chamber width may vary according to chamber volume in involute specimens, whereas both chamber height and width correlate with volume in those tests following an Archimedean spiral. X-ray-tomography shows particular promise in determining which parameters that can be assessed routinely in two dimensions primarily reflect environmental conditions vs. parameters best used for taxonomic identification and for systematic lineage reconstruction.

Laser Ignition Technology for Bi-Propellant Rocket Engine Applications

NASA Technical Reports Server (NTRS)

Thomas, Matt; Bossard, John; Early, Jim; Trinh, Huu; Dennis, Jay; Turner, James (Technical Monitor)

2001-01-01

This viewgraph presentation gives an overview of laser ignition technology for bipropellant rocket engines applications. The objectives of this project include: (1) the selection test chambers and flows; (2) definition of the laser ignition setup; (3) pulse format optimization; (4) fiber optic coupled laser ignition system analysis; and (5) chamber integration issues definition. The testing concludes that rocket combustion chamber laser ignition is imminent. Support technologies (multiplexing, window durability/cleaning, and fiber optic durability) are feasible.

Phase 1 Development Testing of the Advanced Manufacturing Demonstrator Engine

NASA Technical Reports Server (NTRS)

Case, Nicholas L.; Eddleman, David E.; Calvert, Marty R.; Bullard, David B.; Martin, Michael A.; Wall, Thomas R.

2016-01-01

The Additive Manufacturing Development Breadboard Engine (BBE) is a pressure-fed liquid oxygen/pump-fed liquid hydrogen (LOX/LH2) expander cycle engine that was built and operated by NASA at Marshall Space Flight Center's East Test Area. The breadboard engine was conceived as a technology demonstrator for the additive manufacturing technologies for an advanced upper stage prototype engine. The components tested on the breadboard engine included an ablative chamber, injector, main fuel valve, turbine bypass valve, a main oxidizer valve, a mixer and the fuel turbopump. All parts minus the ablative chamber were additively manufactured. The BBE was successfully hot fire tested seven times. Data collected from the test series will be used for follow on demonstration tests with a liquid oxygen turbopump and a regeneratively cooled chamber and nozzle.

Method and system to measure temperature of gases using coherent anti-stokes doppler spectroscopy

DOEpatents

Rhodes, Mark

2013-12-17

A method of measuring a temperature of a noble gas in a chamber includes providing the noble gas in the chamber. The noble gas is characterized by a pressure and a temperature. The method also includes directing a first laser beam into the chamber and directing a second laser beam into the chamber. The first laser beam is characterized by a first frequency and the second laser beam is characterized by a second frequency. The method further includes converting at least a portion of the first laser beam and the second laser beam into a coherent anti-Stokes beam, measuring a Doppler broadening of the coherent anti-Stokes beam, and computing the temperature using the Doppler broadening.

Measurement of Fission Neutron Spectrum and Multiplicity using a Gamma Tag Double Time-of-flight Setup

NASA Astrophysics Data System (ADS)

Blain, E.; Daskalakis, A.; Danon, Y.

2014-05-01

Recent efforts have been made to improve the prompt fission neutron spectrum and nu-bar measurements for Uranium and Plutonium isotopes particularly in the keV region. A system has been designed at Rensselaer Polytechnic Institute (RPI) utilizing an array of EJ-301 liquid scintillators as well as lithium glass and plastic scintillators to experimentally determine these values. An array of BaF2 detectors was recently obtained from Oak Ridge National Laboratory to be used in conjunction with the neutron detectors. The system uses a novel gamma tagging method for fission which can offer an improvement over conventional fission chambers due to increased sample mass. A coincidence requirement on the gamma detectors from prompt fission gammas is used as the fission tag for the system as opposed to fission fragments in a conventional fission chamber. The system utilizes pulse digitization using Acqiris 8 bit digitizer boards which allow for gamma/neutron pulse height discrimination on the liquid scintillators during post processing. Additionally, a 252Cf fission chamber was designed and constructed at RPI which allowed for optimization and testing of the system without the need for an external neutron source. The characteristics of the gamma tagging method such as false detection rate and detection efficiency were determined using this fission chamber and verified using MCNP Polimi modeling. Prompt fission neutron spectrum data has been taken using the fission chamber focusing on the minimum detectable neutron energy for each of the various detectors. Plastic scintillators were found to offer a significant improvement over traditional liquid scintillators allowing energy measurements down to 50 keV. Background was also characterized for all detectors and will be discussed.

SpaceX Crew Dragon Ship

NASA Image and Video Library

2018-05-20

The SpaceX Crew Dragon spacecraft is in the anechoic chamber for electromagnetic interference testing on May 20, 2018, at NASA's Kennedy Space Center in Florida. The Crew Dragon will be shipped to the agency's Plum Brook Station test facility at Glenn Research City in Cleveland, Ohio, for testing in the Reverberant Acoustic Test Facility, the world's most powerful acoustic test chamber. Crew Dragon is being prepared for its first uncrewed test flight, targeted for August 2018.

Slat Heater Boxes for Thermal Vacuum Testing

NASA Technical Reports Server (NTRS)

Ungar, Eugene

2003-01-01

Slat heater boxes have been invented for controlling the sink temperatures of objects under test in a thermal vacuum chamber, the walls of which are cooled to the temperature of liquid nitrogen. A slat heater box (see Figure 1) includes a framework of struts that support electrically heated slats that are coated with a high-emissivity optically gray paint. The slats can be grouped together into heater zones for the purpose of maintaining an even temperature within each side. The sink temperature of an object under test is defined as the steady-state temperature of the object in the vacuum/ radiative environment during the absence of any internal heat source or sink. The slat heater box makes it possible to closely control the radiation environment to obtain a desired sink temperature. The slat heater box is placed inside the cold thermal vacuum chamber, and the object under test is placed inside (but not in contact with) the slat heater box. The slat heaters occupy about a third of the field of view from any point on the surface of the object under test, the remainder of the field of view being occupied by the cold chamber wall. Thus, the radiation environment is established by the combined effects of the slat heater box and the cold chamber wall. Given (1) the temperature of the chamber wall, (2) the fractions of the field of view occupied by the chamber wall and the slat heater box, and (3) the emissivities of the slats, chamber wall, and the surface of object under test, the slat temperature required to maintain a desired sink temperature can be calculated by solving the equations of gray-body radiation for the steady-state adiabatic case (equal absorption and emission by the object under test). Slat heater boxes offer an important advantage over the infrared lamps that have been previously used to obtain desired sink temperatures: In comparison with an infrared lamp, a slat heater box provides a greater degree of sink temperature uniformity for a test-object surface that includes multiple areas with differing optical properties.

Guarded Flat Plate Cryogenic Test Apparatus and Calorimeter

NASA Technical Reports Server (NTRS)

Fesmire, James E. (Inventor); Johnson, Wesley L. (Inventor)

2017-01-01

A test apparatus for thermal energy measurement of disk-shaped test specimens has a cold mass assembly locatable within a sealable chamber with a guard vessel having a guard chamber to receive a liquid fluid and a bottom surface to contact a cold side of a test specimen, and a test vessel having a test chamber to receive a liquid fluid and encompassed on one side by a center portion of the bottom surface shared with the guard vessel. A lateral wall assembly of the test vessel is closed by a vessel top, the lateral wall assembly comprising an outer wall and an inner wall having opposing surfaces that define a thermal break including a condensable vapor pocket to inhibit heat transfer through the lateral wall from the guard vessel to the test vessel. A warm boundary temperature surface is in thermal communication with a lower surface of the test specimen.

Behavior of Ti-5Al-2.5Sn ELI titanium alloy sheet parent and weld metal in the presence of cracks at 20 K

NASA Technical Reports Server (NTRS)

Sullivan, T. L.

1971-01-01

Through- and surface-cracked specimens of two thicknesses were tested in uniaxial tension. Surface-cracked specimens were generally found to be stronger than through-cracked specimens with the same crack length. Apparent surface-crack fracture toughness calculated using the Anderson modified Irwin equation remained relatively constant for cracks as deep as 90 percent of the sheet thickness. Subcritical growth of surface cracks was investigated. Comparison of chamber and open air welds showed chamber welds to be slightly tougher. Both methods produced welds with toughness that compared favorably with that of the parent metal. Weld efficiencies were above 94 percent.

Measuring and modeling surface sorption dynamics of organophosphate flame retardants on impervious surfaces.

PubMed

Liang, Y; Liu, X; Allen, M R

2018-02-01

Understanding the sorption mechanisms for organophosphate flame retardants (OPFRs) on impervious surfaces is important to improve our knowledge of the fate and transport of OPFRs in indoor environments. The sorption processes of semivolatile organic compounds (SVOCs) on indoor surfaces are heterogeneous (multilayer sorption) or homogeneous (monolayer sorption). In this study, we adopted simplified Langmuir isotherm and Freundlich isotherm in a dynamic sink model to characterize the sorption dynamics of OPFRs on impervious surfaces such as stainless steel and made comparisons between the two models through a series of empty chamber studies. The tests involve two types of stainless steel chambers (53-L small chambers and 44-mL micro chambers) using tris(2-chloroethyl)phosphate (TCEP) and tris(1-chloro-2-propyl)phosphate (TCPP) as target compounds. Our test results show that the dynamic sink model using Freundlich isotherm can better represent the sorption process in the empty small chamber. Micro chamber test results from this study show that the sink model using both simplified Langmuir isotherm and Freundlich isotherm can well fit the measured gas-phase concentrations of OPFRs. We further applied both models and the parameters obtained to predict the gas phase concentrations of OPFRs in a small chamber with an emission source. Comparisons between model predictions and measurements demonstrate the reliability and applicability of the sorption parameters. Published by Elsevier Ltd.

Design, construction, prototype tests and performance of a vertex chamber for the MAC detector

NASA Astrophysics Data System (ADS)

Ash, W. W.; Band, H. R.; Bloom, E. D.; Bosman, M.; Camporesi, T.; Chadwick, G. B.; Delfino, M. C.; De Sangro, R.; Ford, W. T.; Gettner, M. W.; Goderre, G. P.; Godfrey, G. L.; Groom, D. E.; Hurst, R. B.; Johnson, J. R.; Lau, K. H.; Lavine, T. L.; Leedy, R. E.; Lippi, I.; Maruyama, T.; Messner, R. L.; Moromisato, J. H.; Moss, L. J.; Muller, F.; Nelson, H. N.; Peruzzi, I.; Piccolo, M.; Prepost, R.; Pyrlik, J.; Qi, N.; Read, A. L.; Ritson, D. M.; Rosenberg, L. J.; Shambroom, W. D.; Sleeman, J. C.; Smith, J. G.; Venuti, J. P.; Verdini, P. G.; Von Goeler, E.; Wald, H. B.; Weinstein, R.; Wiser, D. E.; Zdarko, R. W.

1987-11-01

The design considerations, construction techniques, prototype tests and performance characteristics of a pressurized drift chamber used in the MAC detector at PEP are described. The chamber consists of 324 aluminized mylar tubes of 6.9 mm diameter with wall thickness of 100 μm. With appropriate shielding it operates successfully at 4.6 cm from the beam line. It was simple to construct and was configured to permit any malfunctioning tubes to be remotely disconnected without affecting operation. The chamber operated without problems for two years in the PEP environment with a gas mixture of 49.5% argon, 49.5% CO 2, 1% CH 4, at 4 atm absolute pressure. The mean spatial resolution averaged over all tubes was 45 μm. The time to distance relation for this gas mixture, along with the geometric positioning of individual wires relative to the central tracking chamber, was obtained with data from Bhabha scattering events. We also describe resolution studies performed with a prototype chamber in a SLAC test beam. A wide range of gases, gas pressures, and electronic parameters were explored. These studies proved that resolutions in the 10-50 μm range were possible. Our experience demonstrates that chambers of this type provide high precision tracking and are particularly suited for operation in regions with difficult physical access and/or high ambient radiation levels.

Advanced Small Rocket Chambers. Basic Program and Option 2: Fundamental Processes and Material Evaluation

NASA Technical Reports Server (NTRS)

Jassowski, Donald M.

1993-01-01

Propellants, chamber materials, and processes for fabrication of small high performance radiation cooled liquid rocket engines were evaluated to determine candidates for eventual demonstration in flight-type thrusters. Both storable and cryogenic propellant systems were considered. The storable propellant systems chosen for further study were nitrogen tetroxide oxidizer with either hydrazine or monomethylhydrazine as fuel. The cryogenic propellants chosen were oxygen with either hydrogen or methane as fuel. Chamber material candidates were chemical vapor deposition (CVD) rhenium protected from oxidation by CVD iridium for the chamber hot section, and film cooled wrought platinum-rhodium or regeneratively cooled stainless steel for the front end section exposed to partially reacted propellants. Laser diagnostics of the combustion products near the hot chamber surface and measurements at the surface layer were performed in a collaborative program at Sandia National Laboratories, Livermore, CA. The Material Sample Test Apparatus, a laboratory system to simulate the combustion environment in terms of gas and material temperature, composition, and pressure up to 6 Atm, was developed for these studies. Rocket engine simulator studies were conducted to evaluate the materials under simulated combustor flow conditions, in the diagnostic test chamber. These tests used the exhaust species measurement system, a device developed to monitor optically species composition and concentration in the chamber and exhaust by emission and absorption measurements.

Development and test of combustion chamber for Stirling engine heated by natural gas

NASA Astrophysics Data System (ADS)

Li, Tie; Song, Xiange; Gui, Xiaohong; Tang, Dawei; Li, Zhigang; Cao, Wenyu

2014-04-01

The combustion chamber is an important component for the Stirling engine heated by natural gas. In the paper, we develop a combustion chamber for the Stirling engine which aims to generate 3˜5 kWe electric power. The combustion chamber includes three main components: combustion module, heat exchange cavity and thermal head. Its feature is that the structure can divide "combustion" process and "heat transfer" process into two apparent individual steps and make them happen one by one. Since natural gas can mix with air fully before burning, the combustion process can be easily completed without the second wind. The flame can avoid contacting the thermal head of Stirling engine, and the temperature fields can be easily controlled. The designed combustion chamber is manufactured and its performance is tested by an experiment which includes two steps. The experimental result of the first step proves that the mixture of air and natural gas can be easily ignited and the flame burns stably. In the second step of experiment, the combustion heat flux can reach 20 kW, and the energy utilization efficiency of thermal head has exceeded 0.5. These test results show that the thermal performance of combustion chamber has reached the design goal. The designed combustion chamber can be applied to a real Stirling engine heated by natural gas which is to generate 3˜5 kWe electric power.

Drift chambers on the basis of Mylar tube blocks

NASA Astrophysics Data System (ADS)

Budagov, Yu.; Chirikov-Zorin, I.; Golovanov, L.; Khazins, D.; Kuritsin, A.; Pukhov, O.; Zhukov, V.

1993-06-01

Prototypes of drift chambers constructed of Mylar tube blocks were tested. The purpose of developing tube blocks technology was to create long chambers (up to 3-4 m). Counting and drift characteristics of the chambers for different values of the gas pressure and different diameters of sense wires are presented. The lifetime of the chambers is determined. A photoeffect in the visible spectrum on the surface of the thin film aluminium cathode, which covers the Mylar tubes was observed.

Detection of CO2 leakage by the surface-soil CO2-concentration monitoring (SCM) system in a small scale CO2 release test

NASA Astrophysics Data System (ADS)

Chae, Gitak; Yu, Soonyoung; Sung, Ki-Sung; Choi, Byoung-Young; Park, Jinyoung; Han, Raehee; Kim, Jeong-Chan; Park, Kwon Gyu

2015-04-01

Monitoring of CO2 release through the ground surface is essential to testify the safety of CO2 storage projects. We conducted a feasibility study of the multi-channel surface-soil CO2-concentration monitoring (SCM) system as a soil CO2 monitoring tool with a small scale injection. In the system, chambers are attached onto the ground surface, and NDIR sensors installed in each chamber detect CO2 in soil gas released through the soil surface. Before injection, the background CO2 concentrations were measured. They showed the distinct diurnal variation, and were positively related with relative humidity, but negatively with temperature. The negative relation of CO2 measurements with temperature and the low CO2 concentrations during the day imply that CO2 depends on respiration. The daily variation of CO2 concentrations was damped with precipitation, which can be explained by dissolution of CO2 and gas release out of pores through the ground surface with recharge. For the injection test, 4.2 kg of CO2 was injected 1 m below the ground for about 30 minutes. In result, CO2 concentrations increased in all five chambers, which were located less than 2.5 m of distance from an injection point. The Chamber 1, which is closest to the injection point, showed the largest increase of CO2 concentrations; while Chamber 2, 3, and 4 showed the peak which is 2 times higher than the average of background CO2. The CO2 concentrations increased back after decreasing from the peak around 4 hours after the injection ended in Chamber 2, 4, and 5, which indicated that CO2 concentrations seem to be recovered to the background around 4 hours after the injection ended. To determine the leakage, the data in Chamber 2 and 5, which had low increase rates in the CO2 injection test, were used for statistical analysis. The result shows that the coefficient of variation (CV) of CO2 measurements for 30 minutes is efficient to determine a leakage signal, with reflecting the abnormal change in CO2 concentrations. The CV of CO2 measurements for 30 minutes exceeded 5% about 5 minutes before the maximum CO2 concentration was detected. The contributions of this work are as follows: (1) SCM is an efficient monitoring tool to detect the CO2 release through the ground surface. (2) The statistical analysis method to determine the leakage and a monitoring frequency are provided, with analyzing background concentrations and CO2 increases in a small-scale injection test. (3) The 5% CV of CO2 measurements for 30 minutes can be used for the early warning in CO2 storage sites.

Heat exchanger and related methods

DOEpatents

Turner, Terry D.; McKellar, Michael G.

2015-12-22

Heat exchangers include a housing having an inlet and an outlet and forming a portion of a transition chamber. A heating member may form another portion of the transition chamber. The heating member includes a first end having a first opening and a second end having a second opening larger than the first opening. Methods of conveying a fluid include supplying a first fluid into a transition chamber of a heat exchanger, supplying a second fluid into the transition chamber, and altering a state of a portion of the first fluid with the second fluid. Methods of sublimating solid particles include conveying a first fluid comprising a material in a solid state into a transition chamber, heating the material to a gaseous state by directing a second fluid through a heating member and mixing the first fluid and the second fluid.

Modifications to the nozzle test chamber to extend nozzle static-test capability

NASA Technical Reports Server (NTRS)

Keyes, J. W.

1985-01-01

The nozzle test chamber was modified to provide a high-pressure-ratio nozzle static-test capability. Experiments were conducted to determine the range of the ratio of nozzle total pressure to chamber pressure and to make direct nozzle thrust measurements using a three-component strain-gage force balance. Pressure ratios from 3 to 285 were measured with several axisymmetric nozzles at a nozzle total pressure of 15 to 190 psia. Devices for measuring system mass flow were calibrated using standard axisymmetric convergent choked nozzles. System mass-flow rates up to 10 lbm/sec are measured. The measured thrust results of these nozzles are in good agreement with one-dimensional theoretical predictions for convergent nozzles.

FAST (Four chamber view And Swing Technique) Echo: a Novel and Simple Algorithm to Visualize Standard Fetal Echocardiographic Planes

PubMed Central

Yeo, Lami; Romero, Roberto; Jodicke, Cristiano; Oggè, Giovanna; Lee, Wesley; Kusanovic, Juan Pedro; Vaisbuch, Edi; Hassan, Sonia S.

2010-01-01

Objective To describe a novel and simple algorithm (FAST Echo: Four chamber view And Swing Technique) to visualize standard diagnostic planes of fetal echocardiography from dataset volumes obtained with spatiotemporal image correlation (STIC) and applying a new display technology (OmniView). Methods We developed an algorithm to image standard fetal echocardiographic planes by drawing four dissecting lines through the longitudinal view of the ductal arch contained in a STIC volume dataset. Three of the lines are locked to provide simultaneous visualization of targeted planes, and the fourth line (unlocked) “swings” through the ductal arch image (“swing technique”), providing an infinite number of cardiac planes in sequence. Each line generated the following plane(s): 1) Line 1: three-vessels and trachea view; 2) Line 2: five-chamber view and long axis view of the aorta (obtained by rotation of the five-chamber view on the y-axis); 3) Line 3: four-chamber view; and 4) “Swing” line: three-vessels and trachea view, five-chamber view and/or long axis view of the aorta, four-chamber view, and stomach. The algorithm was then tested in 50 normal hearts (15.3 – 40 weeks of gestation) and visualization rates for cardiac diagnostic planes were calculated. To determine if the algorithm could identify planes that departed from the normal images, we tested the algorithm in 5 cases with proven congenital heart defects. Results In normal cases, the FAST Echo algorithm (3 locked lines and rotation of the five-chamber view on the y-axis) was able to generate the intended planes (longitudinal view of the ductal arch, pulmonary artery, three-vessels and trachea view, five-chamber view, long axis view of the aorta, four-chamber view): 1) individually in 100% of cases [except for the three-vessel and trachea view, which was seen in 98% (49/50)]; and 2) simultaneously in 98% (49/50). The “swing technique” was able to generate the three-vessels and trachea view, five-chamber view and/or long axis view of the aorta, four-chamber view, and stomach in 100% of normal cases. In the abnormal cases, the FAST Echo algorithm demonstrated the cardiac defects and displayed views that deviated from what was expected from the examination of normal hearts. The “swing technique” was useful in demonstrating the specific diagnosis due to visualization of an infinite number of cardiac planes in sequence. Conclusions This novel and simple algorithm can be used to visualize standard fetal echocardiographic planes in normal fetal hearts. The FAST Echo algorithm may simplify examination of the fetal heart and could reduce operator dependency. Using this algorithm, the inability to obtain expected views or the appearance of abnormal views in the generated planes should raise the index of suspicion for congenital heart disease. PMID:20878671

The Third International Cloud Condensation Nuclei Workshop. [conference

NASA Technical Reports Server (NTRS)

Kocmond, W. C.; Rogers, C. R. (Editor); Rea, S. W. (Editor)

1981-01-01

Twenty-five instruments were tested, including size characterization devices and two Aitken counters. The test aerosols were supplied to the instruments by an on-line generation system, thereby eliminating the need for storage bags. Cloud condensation chambers and haze chambers are highlighted.

OVERALL MASS TRANSFER COEFFICIENT FOR POLLUTANT EMISSIONS FROM SMALL WATER POOLS UNDER SIMULATED INDOOR ENVIRONMENTAL CONDITIONS

EPA Science Inventory

Small chamber tests were conducted to experimentally determine the overall mass transfer coefficient for pollutant emissions from still water under simulated indoor-residential or occupational-environmental conditions. Fourteen tests were conducted in small environmental chambers...

Design and use of an exposure chamber for air pollution studies on microarthropods

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

Andre, H.M.

1982-10-01

An exposure chamber for studying the effects of air pollution on microarthropods is described. The chamber was tested on a corticolous mite, Humerobates rostrolamellatus Grandjean (Acari: Oribatida). In the absence of pollutants, the overall mortality was about 2.5%.

Mimicking Mars: a vacuum simulation chamber for testing environmental instrumentation for Mars exploration.

PubMed

Sobrado, J M; Martín-Soler, J; Martín-Gago, J A

2014-03-01

We have built a Mars environmental simulation chamber, designed to test new electromechanical devices and instruments that could be used in space missions. We have developed this environmental system aiming at validating the meteorological station Rover Environment Monitoring Station of NASA's Mars Science Laboratory mission currently installed on Curiosity rover. The vacuum chamber has been built following a modular configuration and operates at pressures ranging from 1000 to 10(-6) mbars, and it is possible to control the gas composition (the atmosphere) within this pressure range. The device (or sample) under study can be irradiated by an ultraviolet source and its temperature can be controlled in the range from 108 to 423 K. As an important improvement with respect to other simulation chambers, the atmospheric gas into the experimental chamber is cooled at the walls by the use of liquid-nitrogen heat exchangers. This chamber incorporates a dust generation mechanism designed to study Martian-dust deposition while modifying the conditions of temperature, and UV irradiated.

Performance of a green propellant thruster with discharge plasma

NASA Astrophysics Data System (ADS)

Shindo, Takahiro; Wada, Asato; Maeda, Hiroshi; Watanabe, Hiroki; Takegahara, Haruki

2017-02-01

A discharge plasma was applied to initiate the combustion of a hydroxylammonium nitrate-based propellant as a substitute for the catalysts that are typically employed. The resulting thrust and thrust-to-power ratio during short interval firing tests as well as the chamber pressure with a single pulse discharge were evaluated. A 1.5-s firing test generated a maximum thrust of 322 mN along with a thrust-to-power ratio of 0.95 mN/W. During the single-pulse discharge trials, pulsed discharge capacitor energies of 5.4, 10.8, and 16.4 J were assessed, and the maximum chamber pressure was found to increase as the energy was raised. The maximum chamber pressures varied widely between experimental trials, and a 16.4-J energy value resulted in the highest chamber pressure of over 1 MPaG. The time spans between the pulsed discharge and the peak chamber pressure were in the range of 1-2 ms, representing a chamber pressure increase rate much higher than those obtained with standard catalysts.

Cyclic hot firing results of tungsten-wire-reinforced, copper-lined thrust chambers

NASA Technical Reports Server (NTRS)

Kazaroff, John M.; Jankovsky, Robert S.

1990-01-01

An advanced thrust liner material for potential long life reusable rocket engines is described. This liner material was produced with the intent of improving the reusable life of high pressure thrust chambers by strengthening the chamber in the hoop direction, thus avoiding the longitudinal cracking due to low cycle fatigue that is observed in conventional homogeneous copper chambers, but yet not reducing the high thermal conductivity that is essential when operating with high heat fluxes. The liner material produced was a tungsten wire reinforced copper composite. Incorporating this composite into two hydrogen-oxygen test rocket chambers was done so that its performance as a reusable liner material could be evaluated. Testing results showed that both chambers failed prematurely, but the crack sites were perpendicular to the normal direction of cracking indicating a degree of success in containing the tremendous thermal strain associated with high temperature rocket engines. The failures, in all cases, were associated with drilled instrumentation ports and no other damages or deformations were found elsewhere in the composite liners.