Bias Voltage Dependency of Structural and Bipolar Plate-Related Properties of Cathodic Arc-Deposited Carbon-Based Coatings.

Carbon-based coatings composed of a chromium interlayer and a carbon top layer were deposited on stainless steel substrates via cathodic arc evaporation. During the carbon deposition, the bias voltage was varied between 900 and 1 V to investigate the influence on the structural, electrical, and electrochemical properties. Raman spectroscopy indicated a dependency of the intensity ratio and G peak position on the bias voltage, which can be attributed to an alteration of the structure. Transmission electron microscopy (TEM) cross-section investigations revealed a graphite-like structure for most carbon top layers but with an increasing amount of disordered fractions, eventually resulting in an amorphous structure at 1 V. To further examine the structure, electron energy loss spectroscopy (EELS) was used. In the high-loss region, distinct π* and σ* peaks could be observed, which agree well with the TEM results. Additionally, analysis of the low-loss region showed that the 1 V carbon top layer exhibits a shifted σ plasmon peak at 20 eV corresponding to an amorphous structure. The carbon-based coatings are highly conductive with low interfacial contact resistance values between 4 and 1.5 mΩ cm2 at 150 N cm-2. From a bias voltage of 200 V, the resistance increases. To evaluate the corrosion resistance, we conducted potentiodynamic polarization tests. At first, with decreasing bias voltage, the corrosion resistance increases and then decreases for both the 100 and 1 V samples. Considering the low thickness, the coating with a carbon top layer deposited at 600 V had the best corrosion resistance. In combination with the excellent contact resistance, the 600 V sample is a highly suitable coating for metallic bipolar plates.

A case-control study on risk factors of domestic accidents in an elderly population.

The aim of this study was to evaluate the combined influence of several lifestyle, health and housing factors in the occurrence of home injuries (HIs) among the elderly. The subjects were recruited from 10 hospitals in Rome, Italy. This study is a paired case-control study. Cases included subjects, aged 65-85 years, who visited the Emergency Department for an HI and were subsequently hospitalised (15 September 2004-30 June 2005). Controls were the subjects of the same gender, age (±3 years) and area of residence of cases. A conditional logistic regression model was used for analysing the variables obtained. In this study, we enrolled 107 hospitalised cases. It was found that the living room was the place where 33% of the accidents occurred. Eighty-seven per cent of the accidents were falls, and 33% of the accidents were the immediate consequence of sudden malaise. One-half of the cases reported one or more leg fractures. The variables that were independently associated with HI were poor household illumination, poor emotional status, regular physical activities and housekeeping activities. We conclude that this study shows the areas of intervention to target HI prevention activities.

Unintentional home injuries reported by an emergency-based surveillance system: incidence, hospitalisation rate and mortality.

OBJECTIVE: The aim of this study is to quantify the incidence of home injuries using an integrated surveillance system. It aims to estimate home accident mortality. MATERIAL AND METHODS: The sources of data for this epidemiological descriptive study were the emergency information system, the hospital information system and the mortality registry of Lazio Region, 2000-2001. We selected all emergency department (ED) visits for unintentional traumas that occurred at home. We calculated incidence of ED visits, hospitalisation and mortality rates by sex and age. RESULTS: In the year 2000, 145101 persons visited the ED (2700/100000), 8.1% of whom were then admitted to the hospital. Incidence was higher among children and older people. We observed 620 fatalities, a rate of 0.43%. The mortality registry reported 1042 deceased, a home accident-related mortality rate of 31.1/100000. CONCLUSIONS: Unintentional injuries in the home are a relevant public health problem. Since none of the databases used in the study give a complete measure of the burden of home injuries, we combined the data from all of them to estimate the mortality and the burden of home injuries. Interventions for prevention must identify the specific accidents/injuries they are trying to reduce in order to focus their intervention on the appropriate population.