Constrained multi-item inventory systeṁs an implicit approach

This paper examines the N-item deterministic inventory model subject to a single linear constraint. Functional relationships between the Lagrangian multipliers and shifts occurring simultaneously in multiple system parameters are identified and used to establish effective initial bounds on the optimal multiplier, Φ^*, in closed form. A recursive process which rapidly converges to Φ^* is also presented. Finally, a comparative analysis highlighting the efficiency of the proposed process in relation to existing algorithms is exhibited.     

Thermoviscous Effects in Steady and Oscillating Flow of Superfluid 4He: Experiments

The correct interpretation of superfluid flow experiments relies on the knowledge of thermal and viscous effects that can cause deviations from ideal behavior. The previous paper presented a theoretical study of dissipative and reactive(nondissipative) thermoviscous effects in both steady and oscillating flow of an isotropic superfluid through small apertures and channels. Here, a detailed comparison is made between the theory and a wide array of experimental data. First, the calculated resistance to steady superflow is compared with measurements taken in a constant pressure-head flow cell. Second, the resonant frequency and Q of three different helmholtz oscillators are compared with predictions based on the calculated frequency response. The resonant frequency and Q are extracted numerically from the frequency response, and analytical results are given in experimentally important limits. Finally, the measured and calculated frequency response are compared at a temperature where the Helmholtz oscillator differs significantly from a simple harmonic oscillator. This difference is used to explain how the thermal properties of the oscillator affect its response. The quantitative agreement between the theory and experiment provide an excellent check of the previously derived equations. Also, the limiting expressions shown in this paper provide simple analytical expressions for calculating the effects of the various physical phenomena in a particular experimental situation.     

Schirmdämpfung inhomogener Metallgehäuse beliebiger Kontur im quasistationären Magnetfeld

Übersicht Die Schirmdämpfung von Metallgehäusen wird bei Wellenlängen größer als die Gehäuseabmessung hauptsächlich durch das magnetische Rückwirkungsfeld der induzierten Wirbelströme erzeugt. Im folgenden Beitrag wird eine allgemeingültige analytische Lösung für die Berechnung der Schirmdämpfung inhomogener Gehäuse, d.h. bestehend aus unterschiedlichen Materialien verschiedener Wandstärke, vorgestellt. Dies gestattet z.B. die Berechnung des Einflusses von Schweißnähten oder verschiedener Frontbleche. Die Herleitung basiert auf der Lösung der Diffusionsgleichung für einzelne homogenene Wandabschnitte unter voller Berücksichtigung des Skineffekts. Mit Hilfe des Induktionsgesetzes in integraler Form wird die Schirmdämpfung des gesamten, Gehäuses ermittelt.

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The shielding effectiveness of nonuniform enclosures in a quasistatic magnetic field

Contents This paper presents a general analytical solution for electromagnetic shielding problems below resonance frequencies. The solution is valid for enclosures of arbitrary shape with any given combination of materials and wall thicknesses. Considering skin effects, the shielding effectiveness is calculated by solving the Helmholtz equation for every single part of the wall with given thickness and material. The solution for the whole shield is then found by applying the Faraday's law in integral form.

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Forschungstätigkeit am Institut für Elektroenergiesysteme und Hochspannungstechnik, Universität Karlsruhe.     

Ovengkol

Ohne Zusammenfassung     

Software features of DBMS kernel in large real-time EMS systems

Improvements made to a relational database management system (DBMS) developed for real-time energy management and control systems for electric utilities are described. The focus is on the software performance improvement features and the dual database concept for coordinated updates. The discussion covers task structuring, buffer usage, active restructuring, and presolving of access routes. Some of these features are applicable to other real-time systems with large databases shared by many application programs. The extension of the DBMS design for use in a hierarchical real-time system is described     

Tear hyperosmolarity in renal dialysis patients asymptomatic for dry eye

Plasma levels of IGF-I, IGFBP-I and IGFBP-3 were measured before and during treatment with tamoxifen up to 19+ months in 34 post-menopausal patients with advanced breast cancer. In 28 patients, pro-IGF-IIE (IGF-IIE) levels were determined and IGFBP-3 was evaluated by immunoblot in 27 patients. Tamoxifen suppressed plasma levels of IGF-I by a mean value of 25.5%-37.7% at different times. This effect was fully developed after 1-2 months of treatment. IGF-IIE was decreased by a mean value of 7.7-23.2% at different time intervals during treatment with tamoxifen, but this effect was significant after long-term treatment (19 months +) only. Plasma IGFBP-I increased by a mean value varying between 48.6% and 190.1%. Tamoxifen had no significant effect on total IGFBP-3 levels. However, patients responding to treatment had a 28% reduction in fragmentation of IGFBP-3, while patients with progressive disease had a 36% increase in fragmentation. The difference between responders and non-responders was highly significant. These findings confirm and extend previous observations regarding the effects of treatment with tamoxifen on IGF-I and IGFBP-I. The finding that patients responding to tamoxifen achieve a reduction in the ratio of fragmented to intact IGFBP-3, while patients progressing on therapy experience an increase in the IGFBP-3 fragmentation ratio, suggest that the tumor burden influences IGFBP-3 protease activity in breast- cancer patients.