Increasing of Reliability of Converter

The innovative activities in steel production invoke exploitation of new machines with the higher production capacity and productivity of labor. The paper deals with deformation and stress analysis of carrying parts of converter pedestal on the base of which the proposals and supporting measures were made that had the aim to increase reliability of the converter during steel production. This was achieved by lifespan prolongation of anchor and connecting bolts of converter pedestal, by change of stiffness of connected elements as well as by correction of nuts of bolted connections. The realization of structural changes decreased loading amplitudes and consequently the vibrations of pedestal. Solution was verified by numerical and experimental procedures of mechanics

Increasing of Reliability of Converter

The innovative activities in steel production invoke exploitation of new machines with the higher production capacity and productivity of labor. The paper deals with deformation and stress analysis of carrying parts of converter pedestal on the base of which the proposals and supporting measures were made that had the aim to increase reliability of the converter during steel production. This was achieved by lifespan prolongation of anchor and connecting bolts of converter pedestal, by change of stiffness of connected elements as well as by correction of nuts of bolted connections. The realization of structural changes decreased loading amplitudes and consequently the vibrations of pedestal. Solution was verified by numerical and experimental procedures of mechanics

Design of an RSFQ Control Circuit to Observe MQC on an rf-SQUID

We believe that the best chance to observe macroscopic quantum coherence (MQC) in a rf-SQUID qubit is to use on-chip RSFQ digital circuits for preparing, evolving and reading out the qubit's quantum state. This approach allows experiments to be conducted on a very short time scale (sub-nanosecond) without the use of large bandwidth control lines that would couple environmental degrees of freedom to the qubit thus contributing to its decoherence. In this paper we present our design of a RSFQ digital control circuit for demonstrating MQC in a rf-SQUID. We assess some of the key practical issues in the circuit design including the achievement of the necessary flux bias stability. We present an "active" isolation structure to be used to increase coherence times. The structure decouples the SQUID from external degrees of freedom, and then couples it to the output measurement circuitry when required, all under the active control of RSFQ circuits. Research supported in part by ARO grant # DAAG55-98-1-0367.Comment: 4 pages. More information and publications at http://www.ece.rochester.edu:8080/users/sde/research/publications/index.htm

Vrednovanje zaostalih naprezanja u zavaru metodom bušenja otvora

Residual stresses arise in the structures without loading during the technological processes, e.g. casting, rolling, welding, and pressing. In the paper is described the process of quantification of residual stresses by the hole-drilling method. For determination of residual stresses were used the procedures in which are supposed constant or linear distributions of stresses along the hole.Zaostala naprezanja nastaju u neopterećenim izradcima tijekom tehnoloških procesa, npr., pri odlijevanju, valjanju, zavarivanju i prešanju. U članku je opisan postupak vrednovanja zaostalih naprezanja u zavarenom spoju primjenom metode bušenja otvora. Za određivanje zaostalih naprezanja rabljen je postupak u kojemu se predmnijeva stalna ili linearna raspodjela naprezanja duž otvora

Vrednovanje zaostalih naprezanja u zavaru metodom bušenja otvora

Residual stresses arise in the structures without loading during the technological processes, e.g. casting, rolling, welding, and pressing. In the paper is described the process of quantification of residual stresses by the hole-drilling method. For determination of residual stresses were used the procedures in which are supposed constant or linear distributions of stresses along the hole.Zaostala naprezanja nastaju u neopterećenim izradcima tijekom tehnoloških procesa, npr., pri odlijevanju, valjanju, zavarivanju i prešanju. U članku je opisan postupak vrednovanja zaostalih naprezanja u zavarenom spoju primjenom metode bušenja otvora. Za određivanje zaostalih naprezanja rabljen je postupak u kojemu se predmnijeva stalna ili linearna raspodjela naprezanja duž otvora

Quantification of Residual Stresses in Hot Rolled Steel Sheets by the Hole Drilling Method

The paper deals with the problems of quantification of residual stresses in hot rolled sheets produced under various regimes. On the base of stress distribution along width and thickness of the belt is pointed out on possibilities of belt deformation from the plane as a result of action of torsional moment as an integral internal quantity in cross-section. For the non-uniformly distributed stresses along the thickness of the sheet the new method for residual stresses determination was developed. Application of the method is described in the paper

The Strain Gage Method for Determination of Input Working Life Parameters of Pipes in Compressor Stations

For determination of safety operation of compressor stations and assessment of their residual working life is necessary to know the levels of residual stresses, operational loading as well as functionality of real support elements and influence of history of previous loading. The method described in the paper was verified several times during solution of problems concerning safety operation of piping yards. The method was also verified by the numerical methods of mechanics

High resolution measurements of the switching current in a Josephson tunnel junction: Thermal activation and macroscopic quantum tunneling

We have developed a scheme for a high resolution measurement of the switching current distribution of a current biased Josephson tunnel junction using a timing technique. The measurement setup is implemented such that the digital control and read-out electronics are optically decoupled from the analog bias electronics attached to the sample. We have successfully used this technique to measure the thermal activation and the macroscopic quantum tunneling of the phase in a small Josephson tunnel junction with a high experimental resolution. This technique may be employed to characterize current-biased Josephson tunnel junctions for applications in quantum information processing.Comment: 10 pages, 8 figures, 1 tabl

Momentum noise in a quantum point contact

Ballistic electrons flowing through a constriction can transfer momentum to the lattice and excite a vibration of a free-standing conductor. We show (both numerically and analytically) that the electromechanical noise power P does not vanish on the plateaus of quantized conductance -- in contrast to the current noise. The dependence of $P$ on the constriction width can be oscillatory or stepwise, depending on the geometry. The stepwise increase amounts to an approximate quantization of momentum noise.Comment: 4 pages including 4 figure