Optimal Provisioning for Single-Echelon Repairable Item Inventory Control in a Time-Varying Environment

This paper presents an algorithm to find a least-cost mix of spares and repair channels, satisfying minimum performance measures, in a single-echelon repairable item inventory system. The monotonicity of the performance measures is the basis for using implicit enumeration in the optimization algorithm. The system analyzed is in a transient environment and is modeled as a birthdeath process with finite state space. The system's transition rates are allowed to vary over time. Transient probabilities are computed using randomization. Illustrative examples are presented.     

Trace metal contamination of evacuated blood collection tubes

A study was undertaken to investigate the magnitude of potential trace metal contamination contributed by various commercial evacuated blood tubes to blood samples under experimental conditions. None of the tubes tested contributed significant Cu contamination whereas the 1% nitric acid and human blood leaching data clearly indicate that Zn, Pb and Cd contamination of blood samples can be a significant problem with certain blood collection tubes under normal handling, shipping and storage conditions. The implications of these experimental findings are discussed. It is recommended that several of the evacuated blood tubes be leach tested prior to use with blood or plasma and the eluate analyzed for potential trace metal contamination problems.     

Electrochimie de ReCl3 en solution: obtention d'un complexe soluble monomere du rhenium trivalent. Etude de son comportement electrochimique

Polarographic and spectrophotometric measurements show that a monomeric species of Re(III) is involved in the hydrolysis of Rhenium (III) chloride. The reduction of this monomeric species was studied by chronopotentiometry. The relevant kinetics is quasi-reversible and leads to a rhenium (I) compound. The apparent transfer coefficient is 0·21 is calculated by the method of Russel and Peterson.     

Fluoride content of prepackaged fruit juices and carbonated soft drinks

Epidemiological studies have established the beneficial effects of water fluoridation. Present dietary trends, however, indicate that many Australian children may consume more prepackaged fluids than actual tap water. The fluoride concentrations of a selection of carbonated soft drinks and prepackaged fruit juices were investigated. The results indicate that, in an optimal fluoride area such as Sydney, children who consume a consistent and large proportion of their fluids as carbonated soft drinks in cans, fruit juices and fruit drinks may not be receiving the full benefit of the water fluoridation.     

Ferromagnetic and antiferromagnetic phase transitions in an itinerant model

The aim of this work is to examine ferromagnetic and antiferromagnetic phase transitions within an itinerant model. Calculating the free energy with the help of the so-called Stoner curves, first-order phase transitions from the paramagnetic to the ferromagnetic state and second-order phase transitions from the paramagnetic to the antiferromagnetic state are found.     

Coherent transmission of 60 FM-SCM video channels

A fiber-optic 60-channel FM video system using coherent subcarrier multiplexing (SCM) is described. Two receiver implementations were studied. For the 60-channel coherent experiment, a carrier-to-noise ratio of 17 dB and a corresponding signal-to-noise ratio of 56 db was achieved with a detected optical power of -32 dBm and a phase modulation index of β-0.07. This represents a 15.2-dB improvement over a similar 60-channel direct-detection FM-SCM system and a 5.6 dB improvement compared to the performance of the system when a semiconductor optical preamplifier was used     

Imaging of electromagnetic resonances in a YBa2Cu3O7- delta bicrystal grain-boundary Josephson junction

The diagnosis of a discontinuous left pulmonary artery arising from a left ductus arteriosus was made by two-dimensional and Doppler echocardiography in an infant with recurrent pneumonia. The diagnosis was later confirmed at cardiac catheterization and surgery. The suprasternal notch views were especially useful for the identification of the left pulmonary artery. In this patient with a right aortic arch, the left pulmonary artery was supplied by a left ductus arteriosus that arose from the innominate artery. This case report describes the echocardiographic diagnosis of discontinuous left pulmonary artery as an isolated lesion, an unusual lesion that can easily be missed. It emphasizes the necessity of a careful and complete examination with particular emphasis on pulmonary artery continuity in patients suspected of having congenital heart disease or respiratory compromise as a result of a cardiovascular cause.