The warehouse scheduling problem: formulation and algorithms

The Warehouse Scheduling Problem is a deterministic multi-item inventory problem with a restriction on warehouse floor space available. We formulate a mixed integer nonlinear programming problem for the objective of minimizing long run inventory holding and order costs per unit of time. We integrate algorithms for staggering orders, described in companion papers, with a heuristic to choose the order sequences. The result is called Sequenced Staggering. We describe a new algorithm to generate order frequencies, called the powers-of-two-factor-of-three technique, as a generalization of Roundy's roundoff technique for powers-of-two policies. We report on a computational study of four hybrid algorithms for solving the warehouse scheduling problem, including the competing algorithm of Gallego, Queyranne, and Simchi-Levi. Based on these results, we recommend the combination of powers-of-two frequencies with Sequenced Staggering.     

State composition standards for aqueous media

Translated from Izmeritel'naya Tekhnika, No. 11, pp. 66–67, November, 1994.     

Transition metal joints for steam generators—An overview

The transition metal joint (TMJ) between an austenitic stainless steel and a chromium-molybdenum (Cr-Mo) ferritic steel used widely in steam generators of power plants has for a long time presented problems relating to premature failures in service. The direct (bimetallic) TMJ presently in use is designed for a service life of about 200,000 h; but such TMJs with iron-base weld metals have been failing in service within about one-third of their design lifetime, while their counterparts with nickel-base weld metals fail within about one-half of their design lifetime. The causes for such premature service failures of these TMJs are discussed in detail, leading to the development of improved TMJs. One of the improved TMJs with a trimetallic configuration of austenitic stainless steel/Alloy 800/Cr-Mo ferritic steel is discussed in detail, covering its development, characterisation and evaluation. Accelerated performance tests in the laboratory have indicated a four-fold improvement in the service life of the TMJ with this trimetallic configuration compared to the bimetallic configuration. The metallurgical details of these studies are also discussed in this paper.     

Synthesis and biological studies on analogs of cyclolinopeptide A with a shortened peptide chain

Continuing our work on the immunosuppressive activity of cyclolinopeptide A (CLA), a cyclic nonapeptide of the sequence: c-(-Leu-Ile-Ile-Leu-Val-Pro-Pro-Phe-Phe), we synthesized a series of 6 linear analogs of CLA, successively shortened at the N-terminus of the peptide chain. Immunosuppressive activity of acetates as well as trifluoroacetates of these peptides was investigated using PFC (humoral immunity) and DTH (cellular immunity) tests. It was found that the immunosuppressive potency of the peptides examined diminishes with shortening of the peptide chain. Octapeptide I with the sequence Ile-Ile-Leu-Val-Pro-Pro-Phe-Phe was found to be the most active of the whole series. The immunosuppressive activity increased again for a tripeptide fragment of CLA of the sequence Pro-Phe-Phe. The immunosuppressive activity of octapeptide probably depends on the suppression of IL-1, IL-6 and TNF production by the cells involved in immune and inflammatory response.     

Charge-based capacitance measurements (CBCM) on MOS devices

A new simple method of measuring capacitance-voltage characteristics of MOS devices is presented. Proceeding from the charge-based capacitance measurement technique suggested recently, a compact test structure with high resolution has been developed, which only requires measurement of do quantities. The method was tested on a 0.6-μm CMOS process with small and large area capacitors and compared to well-known high-frequency capacitance-voltage results. Beside using a reference structure, a second means of extracting parasitic effects is demonstrated for small structures. The test structure allows measurements in a wide frequency range with high accuracy and low noise contribution at small capacitance levels     

Analysis of slots in nonradiating dielectric waveguide using the modal expansion method

A modal expansion method is used with the reciprocity and Poynting theorems to derive the admittance of inclined slots cut in the metal wall of a nonradiating dielectric (NRD) waveguide. Theoretical values of normalised conductance and susceptance are compared with previously reported experimental results and are found to be in good agreement.<>     

New wire interface for graded 3-D TLM

A new 3-D graded TLM model for thin radiating wires is presented. The model differs from previous TLM models because the wire is modelled at the interfaces between cells, rather than through the centre of the node. The connection between the TLM symmetrical condensed-node link lines and the line forms a 'wire interface'. The scattering algorithm for the interface and simulation results are given.<>     

Performance of 1700 m2 solar pond operation in arid zone

A 1700 m² solar pond was constructed in the desert of Kuwait where severe weather conditions prevail in all seasons. The paper describes in detail a diffuser design for the gradient establishment, gradient stability, and thermal performance of the pond. The main problem encountered in operating the pond was mixing between the upper zone and the gradient zone, even when the wind speed was as low as 5 m/s. No mixing between the gradient and the lower connective zone was observed. The wind effect was severe in causing mixing even when the upper convective zone increased to 0.90 m.