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High density sintering of iron-carbon alloys via transient liquid phase

Description: Because of the transient presence of a liquid phase during sintering of graphite coated iron powder, a high percentage (95% to approx. 99.4%) of theoretical density can be achieved in a short time (approx. 10 min.) and at a moderate temperature (1175/sup 0/C). As a result, the mechanical properties of the graphite coated sintered steel are close to those of commercial plain carbon steels and much better than those of commercial powder metallurgy sintered steels. In addition, the physical and mechanical properties of Fe 2% C 20% W were studied in the as-sintered condition.
Date: June 1, 1978
Creator: Lam, T.T.
Partner: UNT Libraries Government Documents Department

Backup power working group best practices handbook for maintenance and operation of engine generators, Volume 1. Revision 1

Description: This handbook is divided into the four chapters. Chapter one covers the design, procurement, storage, handling and testing of diesel fuel oil to be used in DOE backup power supplies. Chapter two discusses the selection of automatic transfer switches to be used in DOE backup power supplies. Chapter three is about low voltage open frame air circuit breaker operation, testing, and maintenance for DOE backup power supplies. And chapter four covers installation, design, and maintenance of engine cooling water and jacket water systems.
Date: June 1, 1997
Creator: Gross, R.; Padgett, A.B.; Burrows, K.P.; Fairchild, P.N.; Lam, T. & Janes, J.
Partner: UNT Libraries Government Documents Department

Correlation between nuclear response and defects in CZT

Description: Vertical high pressure Bridgman (VHPB) was considered until now to be the most successful crystal growth method to produce Cd{sub 1{minus}x}Zn{sub x}Te (CZT), (0.04 < x < 0.24), for X- and gamma-ray detector crystals. Recently Horizontal Bridgman (HB) Cd{sub 1{minus}x}Zn{sub x}Te crystals produced by IMARAD Co. have also been successfully fabricated into nuclear spectroscopic radiation detectors. In view of the database of many years' study of the electrical properties of VHPB CZT grown and obtained from various sources, the authors also studied the HB CZT crystals in order to compare the defects present in both different kinds of crystals grown by different methods. The VHB-grown samples were examined using thermoelectric emission spectroscopy (TEES), X- and gamma ray spectroscopy and laser induced transient charge technique (TCT). The surface and the bulk crystalline homogeneity were mapped using triaxial double crystal x-ray diffraction (TADXRD) and infrared transmission spectroscopy (IR). They have found a correlation between crystallinity, IR transmission microstructure and trapping times. Spectrometer grade VHPB CZT crystals exhibit trapping times of 20 {micro}s for electrons and 7 {micro}s for holes, however, regions, which were opaque to IR transmission, had trapping times shorter by one order of magnitude. The trapping times of HB CZT for electrons, were 10--15 {micro}s. A similar trend has been observed on VHPB CZT crystals with poor crystallinity. The HB CZT crystals that they measured in this study had a crystallinity that was inferior to that of the best spectroscopic grade VHPB crystals.
Date: July 19, 1999
Creator: Hermon, H.; Schieber, M.; James, R. B.; Lee, E.; Cross, E.; Goorsky, M. et al.
Partner: UNT Libraries Government Documents Department