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  • 1
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    Smoldering, Transition and Flaming in Microgravity (2001)
    In:  CASI
    Details
    Publication Date: 2019-07-10
    Description: A research project is underway to study smolder and the transition to flaming in microgravity. The Microgravity Smoldering Combustion (MSC) flight project is an ongoing research project to provide a better understanding of the controlling mechanisms of smoldering combustion. The Smoldering Transition and Flaming (STAF) project is a recently established research program that will utilize the Fluids and Combustion Facility (FCF) of the ISS to examine the transition from smolder to flaming in microgravity. In forced flow smolder experiments ambient pressure in the MSC chamber rises, thus motivating the need to understand the effects of pressure on smoldering combustion. Further, the STAF experiment has constraints on experimental scale and testing at elevated pressure may be a mechanism to reduce the sample size by enhancing the smolder reaction. In the work we are reporting here, a series of ground-based tests determine the effects of pressure on smoldering combustion. These tests are compared with data obtained from experiments conducted aboard the Space Shuttle in flights STS-69 and STS-77. Measurements of one-dimensional smolder propagation velocity are made by thermocouple probing and a non-intrusive Ultrasound Imaging System (UIS)]. Thermocouples are also used to obtain reaction temperatures and the UIS is used to determine permeabilities of the fuel in real-time.
    Keywords: Inorganic, Organic and Physical Chemistry
    Type: Sixth International Microgravity Combustion Workshop; 21-24; NASA/CP-2001-210826
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    NASA TECHNICAL REPORTS
  • 2
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    Modeling the interaction Between Ethylene Diamine and Water Films on the Surface of a Carbon Nanotube (2004)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: It has been observed that a carbon nanotube (CNT) AFM tip coated with ethylene diamine (EDA) penetrates the liquid water-air interface more easily than an uncoated nanotube tip. The EDA coating remains intact through repeated cycles of dipping and removal. In order to understand the physical basis for this observation, we use ab initio quantum chemistry calculations to study the EDA-CNT-water interaction and to parameterize a force field describing this system. Molecular dynamics (MD) simulations are carried out for EDA-water mixtures and an EDA-coated carbon nanotube immmed in water. These simulations are similar to our earlier MD study that characterized the CNT-water interface. The attractive CNT-EDA and CNT-water interactions arise primarily from van der Waals forces, and the EDA-EDA, EDA-water and water-water interactions are mainly due to hydrogen bond formation. The binding energ of single EDA molecule to the nanotube is nearly three times larger than the corresponding value found for water (4.3 versus 1.5 kcal mol, respectively). The EDA molecules readily stick to and diffuse along the CNT surface. As a resulf mixing of the EDA and water films does not occur on the timescale of the MD simulations. The EDA film reduces the hydrophobicity of the nanotube surface and acts like a prototypical surfactant in stabilizing the suspension of carbon nanotubes in water. For this presentation, we use the MD simulations to determine how the presence of the carbon nanotube surface perturbs the properties of EDA-water mixtures.
    Keywords: Inorganic, Organic and Physical Chemistry
    Type: Electrochemical Society 2004th Meeting; Oct 03, 2004 - Oct 08, 2004; Honolulu, HI; United States
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    NASA TECHNICAL REPORTS
  • 3
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    Ultrasound Imaging System Implementation and Ignition Protocol for the Microgravity Smoldering Combustion (MSC) Experiments (1999)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The Microgravity Smoldering Combustion (MSC) experiment is a study of the smolder characteristics of porous combustible materials in a microgravity environment. The objective of the study is to provide a better understanding of the controlling mechanisms of smolder, both in microgravity and normal earth gravity. Experiments have been conducted aboard the NASA Space Shuttle in the Get Away Special Canister (GAS-CAN), an apparatus requiring completely remote operation. Future GAS-CAN experiments will utilize an ultrasound imaging system (UIS) which has been incorporated into the MSC experimental apparatus. Thermocouples are currently used to measure temperature and reaction front velocities. A less intrusive method is desirable, however, as smolder is a very weak reaction and it has been found that heat transfer along the thermocouple is sufficient to affect the smolder reaction. It is expected that the UIS system will eventually replace the existing array of thermocouples as a non-intrusive technique without compromising data acquisition. The UIS measures line of sight permeability, providing information about the reaction front position and extent. Additionally, the ignition sequence of the MSC experiments has been optimized from previous experiments to provide longer periods of self-supported smolder. An ignition protocol of a fixed power to the igniter for a fixed time is now implemented. This, rather than a controlled temperature profile ignition protocol at the igniter surface, along with the UIS system, will allow for better study of the effect of gravity on a smolder reaction.
    Keywords: Inorganic, Organic and Physical Chemistry
    Type: AIAA Paper 99-0699 , Aerospace Sciences; Jan 11, 1999 - Jan 14, 1999; Reno, NV; United States
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  • 4
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    Theoretical Prediction of Microgravity Ignition Delay of Polymeric Fuels in Low Velocity Flows (2001)
    In:  CASI
    Details
    Publication Date: 2019-07-10
    Description: A new flammability apparatus and protocol, FIST (Forced Flow Ignition and Flame Spread Test), is under development. Based on the LIFT (Lateral Ignition and Flame Spread Test) protocol, FIST better reflects the environments expected in spacebased facilities. The final objective of the FIST research is to provide NASA with a test methodology that complements the existing protocol and provides a more comprehensive assessment of material flammability of practical materials for space applications. Theoretical modeling, an extensive normal gravity data bank and a few validation space experiments will support the testing methodology. The objective of the work presented here is to predict the ignition delay and critical heat flux for ignition of solid fuels in microgravity at airflow velocities below those induced in normal gravity. This is achieved through the application of a numerical model previously developed of piloted ignition of solid polymeric materials exposed to an external radiant heat flux. The model predictions will provide quantitative results about ignition of practical materials in the limiting conditions expected in space facilities. Experimental data of surface temperature histories and ignition delay obtained in the KC-135 aircraft are used to determine the critical pyrolysate mass flux for ignition and this value is subsequently used to predict the ignition delay and the critical heat flux for ignition of the material. Surface temperature and piloted ignition delay calculations for Polymethylmethacrylate (PMMA) and a Polypropylene/Fiberglass (PP/GL) composite were conducted under both reduced and normal gravity conditions. It was found that ignition delay times are significantly shorter at velocities below those induced by natural convection.
    Keywords: Inorganic, Organic and Physical Chemistry
    Type: Sixth International Microgravity Combustion Workshop; 85-88; NASA/CP-2001-210826
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  • 5
    Electronic Resource
    Electronic Resource
    Fixation of Carbon Dioxide by Oxalic Amidinato Magnesium Complexes: Structures and Reactions of Trimetallic Magnesium Carbamato and Related Complexes (2000)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 2000 (2000), S. 1055-1064 
    Details
    ISSN: 1434-1948
    Keywords: Carbon dioxide fixation ; Magnesium ; N ligands ; C-C coupling ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of oxalic amidines R1-N=C(NHR2)-C(NHR2)=N-R1 with CH3MgX followed by uptake of CO2 results in the formation of the trimeric carbamato complexes [R1-N=C(NR2-COO)-C(NR2COO)=N-R1]3Mg3(THF)6 (2a: R1 = R2 = Ph; 2b: R1 = R2 = p-tolyl) as the thermodynamically stable final products of the reaction. Their X-ray crystal structures show that the three metal centres are in a linear arrangement. The central magnesium ion is octahedrally surrounded by six O-donor atoms of the μ2-carbamato bridges, while both peripheral magnesium ions are facially coordinated by three O-donor atoms of the carbamato groups and three THF molecules. This coordination sphere can be considered as a structural model for the active centre in the ribulose-1,5-bisphosphate carboxylase/oxygenase enzyme. Compound 2a reacts with ZnCl2 or CoBr2, with CO2 elimination, to form dimeric complexes of the type [X2M(oxalamidinato)MX2][Mg(DMF)6] (M = Zn, Co; X = Cl, Br). X-ray crystal structure analyses show that the d-metals are tetrahedrally coordinated. The magnesium-bromide-containing intermediates in the formation of 2a and 2b are able to transfer CO2 to acetophenone, thus simulating the CO2 activation step in enzymatic biotin-dependent carboxylation reactions.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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    Paper (German National Licenses)
  • 6
    Electronic Resource
    Electronic Resource
    Crystal structure and electrical properties of κ-((S,S)-DMBEDT-TTF)2ClO4 (1992)
    Weinheim : Wiley-Blackwell
    Advanced Materials 4 (1992), S. 33-35 
    Details
    ISSN: 0935-9648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/adma.19920040106
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  • 7
    Electronic Resource
    Electronic Resource
    C-Substituierte 1,2,3,5-Dithiadiazoliumsalze und 1,2,3,5-Dithiadiazolyle (1994)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 336 (1994), S. 266-268 
    Details
    ISSN: 0941-1216
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Carbon Substituted 1,2,3,5-Dithiadiazolium Salts and 1,2,3,5-Dithiadiazolyles
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19943360315
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  • 8
    Electronic Resource
    Electronic Resource
    Theorie der Ergänzung von Phosphatierungsbädern. (Zur Bildungsgeschwindigkeit sekundärer Deckschichten auf Metallen) (1959)
    Weinheim [u.a.] : Wiley-Blackwell
    Materials and Corrosion/Werkstoffe und Korrosion 10 (1959), S. 761-767 
    Details
    ISSN: 0947-5117
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: A theory on the complementing process in phosphating baths(Formation rate of secondary cover layers on metals)Secondary cover layers are deposited on metals from saturated solutions if the equilibrium of the solution is disturbed by corrosion on the metal surface. The rate of corrosion and the rate at which the layer is formed are compared, using the phosphate treatment of iron as an example. With this process, the quotient of the HṠ consumed and the iron dissolved is governed by the stoichiometry of the oxidation reaction concerned. The quotients of the HṠ consumed and the quantity of the zinc phosphate deposit can be calculated if all reactions are diffusion controlled. It is thus assumed that the crystal nuclei are formed rapidly, and that equilibria between zinc and phosphoric acid in the solution remain adjusted upto the metal surface. This theory is confirmed experimentally. It serves to indicate and to determine the composition of complementry solution by means of which the baths can be kept stable.
    Notes: Sekundäre Deckschichten scheiden sich aus gesättigten Lösungen auf Metallen ab, wenn an der Metalloberfläche das Lösungsgleichgewicht durch Korrosion gestört wird. Die Geschwindigkeiten von Korrosion und Abscheidung werden am Beispiel der Phosphatierung von Eisen verglichen. Dabei ist der Quotient aus verbrauchtem H und gelöstem Eisen durch die Stöchiometrie der jeweiligen Oxydationsreaktion bedingt. Der Quotient aus verbrauchten H und Menge des Zinkphosphatniederschlags ist zu berechnen, wenn alle Reaktionen transportbestimmt sind. Es wird also angenommen, daß die Gleichgewichte zwischen Zink und Phosphorsäure in der Lösung bis hin zur Metalloberfläche eingestellt bleiben. Die Theorie wird experimentell bestätigt. Sie dient dazu, um Bäder mit optimalen Eigenschaften anzugeben. Ferner erlaubt sie, die Zusammensetzung von Ergänzungslösungen zu berechnen, mit denen die Bäder stationär gehalten werden können.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/maco.19590101205
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  • 9
    Electronic Resource
    Electronic Resource
    Korrosion organischer Kunststoffe durch HautschweißHerrn Prof. Dr. E. Rabald zum 65. Geburtstag gewidmet (1964)
    Weinheim [u.a.] : Wiley-Blackwell
    Materials and Corrosion/Werkstoffe und Korrosion 15 (1964), S. 2-7 
    Details
    ISSN: 0947-5117
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Corrosion of organic plastics, caused by perspiration of the skinPrompted by contact damage caused to technical utensils by perspiration of the skin, corrosion tests have been carried out with different organic plastics in different synthetic perspiration solutions frequently encountered. The tested materials, which belonged to different groups (plastics with synthetic resins through condensation; plastics with synthetic resins through polymerisation; cellulose and cellulose derivatives; casein products), showed considerable differences in their behaviour, not only in different perspiration solutions but also among each other, so that they can be divided into three resistance classes.
    Notes: An technischen Gebrauchsgegenständen durch Hautschweiß aufgetretene Berührungsschäden führten zur Durchführung von Korrosions-Standversuchen mit verschiedenen organischen Kunststoffen in verschiedenen, häufig benutzten synthetischen Schweißlösungen. Die Versuchs-Werkstoffe, die verschiedenen Stoffgruppen (Kunststoffe mit Kunstharzen durch Kondensation, Kunststoffe mit Kunstharzen durch Polymerisation, Cellulose- und Cellulosederivate, Caseinprodukte) angehörten, zeigten einmal in den verschiedenen Schweißlösungen, zum andern untereinander ein stark unterschiedliches, schließlich in drei Beständigkeitsgruppen eingruppiertes Verhalten.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/maco.19640150103
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  • 10
    Electronic Resource
    Electronic Resource
    Inihibition der Korrosion von Kupfer und Messing in Ammoniumchlorid-Lösungen durch Kolloide (1963)
    Weinheim [u.a.] : Wiley-Blackwell
    Materials and Corrosion/Werkstoffe und Korrosion 14 (1963), S. 11-14 
    Details
    ISSN: 0947-5117
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Inhibiting the corrosion of copper and bronze in ammonium chloride solutions by colloidsInspired by tests carried out by F. D. Talati, M. N. Desai and A. M. Trivedi, the author has carried out solubility tests with pure copper and with bronzes Ms 60 and Ms 70 in 0.1 n-NH4Cl with and without inhibitor content (the latter consisting of the colloids agar and/or gelatine). In the solution free from inhibitor, copper shows the highest corrosion rate, and Ms 60 has a clearly higher rate than Ms 70. As a result of admixtures of agar or gelatine, the copper corrosion caused by the NH4Cl solution is greatly reduced, whilst on the other hand, admixtures consisting of agar and gelatine greatly activate the corrosion attack. Moreover, whilst both types of bronze are protected against NH4Cl corrosion by agar or gelatine admixtures to roughly the same extent, a different proportion of both agar and gelatine added together will result in an inhibition effect which differs in principle, and which may be either positive or negative.
    Notes: Angeregt durch Versuche von F. D. Talati, M.N. Desai and A. M. Trivedi wurden mit Reinkupfer und den Messingen Ms 60 und Ms 70 Löslichkeitsversuche in inhibitorfreier und in inhibitorhaltiger (Zusätze der Kolloide Agar oder/und Gelatine) O, 1n-NH4Cl durchgeführt. In der inhibitorfreien Lösung wird Kupfer am Stärksten angegriffen. Messing Ms 60 wird deutlich stärker angegriffen als Ms 70. Agar- oder Gelatine-Zusätze setzen den Angriff der NH4Cl-Lösung auf Kupfer stark herab, während Agar- und Gelatine-Zusätze den Angriff stark aktivieren. Während weiter beide Messing-Sorten durch Agar- Oder Gelatine-Zusätze etwa in dem gleichen Ausmaße vor dem Angriff der NH4Cl-Lösung geschützt werden, ergibt der unterschiedlich hohe Zusatz der Inhibitorgemische (Agar und Gelatine) grundsätzlich unterschiedliche Hemmstoff-Wirkungen, und zwar positive oder negative Hemmstoff effekte.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/maco.19630140103
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