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Calorimeter Preamplifier Hybrid Circuit Test Jig

Description: There are two ways in which the testing may be initiated, remotely or locally. If the remote operation is desired, an external TTL level signal must be provided to the test jig with the remotellocal switch on the side of the test jig switched to remote. A logic high will initiate the test. A logic low will terminate the test. In the event that an external signal is connected to the test jig while local operation occurs, the local control takes precedence over remote control. Once a DVT has been locked in the ZIF socket and the DIP switches are selected, the Push-to-Test button may be depressed. Momentarily depressing the button will initiate a test with a minimum 400 ms duration. At the same time a PBCLOCK and PBLATCH pulses will be initiated and the power rails +12V, +8V, and -6V will be ramped to full voltage. The time at which the power rails reach the full voltage is about 13 ms and it is synchronized with bypass capacitors placed on COMP input of U20 and U22 and on the output of U23 voltage regulators. The voltage rails are supplied to a {+-}10% window comparator. A red LED indicates the rail is below or above 10% of the design value. A green LED indicates the rail is within acceptable limits. For DDT with a 5 pF and 10 pF feed back capacitor, the +12V and +8V rails are current-regulated to 19rnA and 22 rnA respectively and the -6V rail is short-circuit protected within the regulator. For DUT with a 22 pF feed back capacitor the current regulation is the same as above except that the +8V rail is current regulated to 43 rnA. The power rails are supplied to the DUT via a 10 {Omega} resistor. The voltage drop across ...
Date: April 19, 1999
Creator: Abraham, B.M.
Partner: UNT Libraries Government Documents Department

Shear rigidity of spread stearic acid monolayers on water

Description: The effect of Al/sup 3 +/, Fe/sup 3 +/, Ca/sup 2 +/, and Mg/sup 2 +/ ions and of pH on the two-dimensional shear modulus of stearic acid spread on a water substrate was determined. A large shear modulus was displayed by the films when the subphase contained Al/sup 3 +/ and Fe/sup 3 +/ ions at the self buffered pH. With Fe/sup 3 +/ dissolved in the subphase, the film displayed a viscous relaxation when strained but no residual stress was observed. No effect was observed with the Ca/sup 2 +/ or Mg/sup 2 +/. Reducing the pH value in the subphase with the trivalent ions caused the shear modulus to disappear. The observations are interpreted in terms of hydrogen bonding.
Date: January 1, 1981
Creator: Abraham, B.M.; Ketterson, J.B.; Miyano, K. & Kueny, A.
Partner: UNT Libraries Government Documents Department

Experimental verification of the mercury--iodine thermochemical cycle for the production of hydrogen from water, ANL-4

Description: The thermochemical hydrogen-producing cycle ANL-4 consists of the reactions: 2NH/sub 3/ + 2KI + 2CO/sub 2/ + 2H/sub 2/O ..-->.. 2NH/sub 4/I + 2KHCO/sub 3/, 2KHCO/sub 3/ ..-->.. K/sub 2/CO/sub 3/ + CO/sub 2/ + H/sub 2/O, Hg + 2NH/sub 4/I ..-->.. 2NH/sub 3/ + HgI/sub 2/ + H/sub 2/, and HgI/sub 2/ + K/sub 2/CO/sub 3/ ..-->.. 2KI + Hg + CO/sub 2/ + 1/20/sub 2/. The maximum temperature required by the cycle is 1000 K. The calcination reaction is well-known to take place around 475 K and has been described in the literature. The other three reactions have been subjected to experimental verification, and yields and reaction rates have been measured. A flow diagram for the cycle has been constructed, and an overall practical efficiency of 28% in terms of ..delta..G/sub f/(H/sub 2/O)/(total heat input) has been estimated from the new data. A substantial portion of the total heat input is required for the isolation of the ammonium iodide. Our results indicate that the cycle should be capable of producing hydrogen from water with reasonable efficiency and without requiring heat at an unduly high temperature. The cycle should therefore be suitable for a practical demonstration of the technical feasibility of thermochemical hydrogen generation.
Date: January 1, 1978
Creator: Appelman, E. H.; Schreiner, F. & Abraham, B. M.
Partner: UNT Libraries Government Documents Department