Layer-by-layer growth of solid4He on graphite

Recent experiments by Maynard et al on fourth sound in a Grafoil-filled⁴He cell show a periodic dependence of the resonant frequency on the average number of solid layers. We interpret their sharp minima as resulting from the inherent smoothness of complete layers, which inhibits the propagation of waves of melting and freezing, and reduces their damping and their coupling to fourth sound. Using a lattice-gas model, we study the roughness of incomplete surface layers, and suggest how this can lead to the observed broad maxima. We predict that the maxima of damping and of resonant frequency coincide.     

Experimental observation of rainbow scattering by a coated cylinder: twin primary rainbows and thin-film interference

We experimentally examine the primary rainbow created by the illumination of a coated cylinder. We present a simple technique for varying the coating thickness over a wide range of values, and we see evidence for two different scattering regimes. In one, where the coating thickness is large, twin rainbows are produced. In the second, where the coating is thin enough to act as a thin film, a single rainbow is produced whose intensity varies periodically as the coating thickness varies. We find good agreement with previous theoretical predictions.     

Terrestrial laser scanning for estimating urban tree volume and carbon content

The acquisition of single-tree-related information is an important task, especially in urban areas where there is an increasing interest in standing carbon stock. Therefore, an easy and robust method was developed to extract the volume, diameter at breast height (DBH) and height of single trees from point clouds of terrestrial laser scanning. For data acquisition, nine trees were scanned from several positions and the resulting high-resolution point clouds (20–60 million points) were analysed by an algorithm based on voxel structure. First, noise reduction was carried out, followed by filling of voxels inside the stem and branches through the intersection of four orthogonal viewing directions. After the elimination of erroneously generated fillings, volume was determined layer-wise for each cross section. For quality assessment, nine deciduous trees were selected, cut, weighed and analysed for wet specific gravity and carbon content in order to provide a control value. The estimated volumes agree with the control value within a range of –5.1% to +14.3%. This is also the case with DBH values; however, heights are systematically underestimated.     

The effects of fluorine on parametrics and reliability in a0.18-μm 3.5/6.8 nm dual gate oxide CMOS technology

Fluorine was introduced into the gate oxide by implantation at various doses into the gate polysilicon. After complete processing, the fluorine remaining in the system was characterized by secondary ion mass spectroscopy (SIMS) and then correlated to a number of important technological device parameters. The threshold voltages of thin (3.5 nm) and thick (6.8 nm) field-effect transistors (FETs) were measured, and an increase in interface trap density with increasing fluorine content was identified. An increase in oxide thickness and improvement in hot-carrier immunity were observed. Little change to oxide dielectric integrity was noted, but the negative bias threshold instability (NBTI) shift was improved with the introduction of fluorine. These data indicate that benefits may be obtained by introducing fluorine into the p-type FET (PFET), but that the increase in interface traps makes fluorine in the n-type FET (NFET) less attractive from a technological perspective. These data are in agreement with a previously proposed mechanism whereby fluorine removes hydrogen-related sites from the oxide     

Objective and subjective socioeconomic status and susceptibility to the common cold.

Objective: We ask whether subjective socioeconomic status (SES) predicts who develops a common cold when exposed to a cold virus. Design: 193 healthy men and women ages 21-55 years were assessed for subjective (perceived rank) and objective SES, cognitive, affective and social dispositions, and health practices. Subsequently, they were exposed by nasal drops to a rhinovirus or influenza virus and monitored in quarantine for objective signs of illness and self-reported symptoms. Main Outcome Measures: Infection, signs and symptoms of the common cold, and clinical illness (infection and significant objective signs of illness). Results: Increased subjective SES was associated with decreased risk for developing a cold for both viruses. This association was independent of objective SES and of cognitive, affective and social disposition that might provide alternative spurious (third factor) explanations for the association. Poorer sleep among those with lesser subjective SES may partly mediate the association between subjective SES and colds. Conclusions: Increased Subjective SES is associated with less susceptibility to upper respiratory infection, and this association is independent of objective SES, suggesting the importance of perceived relative rank to health. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A new method for the determination of direct insolation

A method of determining direct normal insolation by using two fixed pyranometers was developed and tested. Experimental data for two different configurations are presented. The results are such that the method presented could reasonably be substituted for the standard tracking pyrheliometer in situations in which the use of such a pyrheliometer is not practicable.     

Management of traction wire fracture complicating mechanical basket lithotripsy

BACKGROUND AND STUDY AIMS: The application of basket catheters has become the main method of removing calculi from the biliary and pancreatic duct. However, larger or impacted stones have to be crushed and fragmented by mechanical lithotriptors before removal is possible. Sometimes, fracture of the traction wire occurs as a severe and fraught complication. We describe a precautionary measure which helps to manage this complication. PATIENTS AND METHODS: In a series of 569 consecutive patients suffering from bile or pancreatic duct stones we found 60 (10.5%) who required mechanical lithotripsy for oversized or impacted calculi. Mechanical lithotripsy was always performed initially with a long metal sheath (80 cm) in combination with a standard traction wire. If the traction wire fractured we replaced the long metal sheath stepwise by shorter ones (70cm, 60cm and 50 cm, respectively), allowing immediate continuation of the lithotriptic procedure using the same traction wire. RESULTS: During the lithotriptic procedure three of our patients (5%) were afflicted by traction wire fracture. Two patients could be relieved directly by changing the initial metal sheath to shorter ones. Because of the exceptional hardness of a pancreatic duct stone the third patient needed stone fragmentation by extracorporeal shock wave lithrotripsy (ESWL) before complete mechanical clearance of the duct could be accomplished. CONCLUSION: We advocate the initial use of a long metal sheath (80cm) to perform mechanical lithotripsy. In case of traction wire fracture the use of a shorter metal sheath allows immediate successful continuation of the procedure, thereby frequently avoiding procedures such as ESWL or surgery.     

Effect of Biotrickling Filter Operating Parameters on Chlorobenzenes Degradation

In this paper the effect of operating parameters on biotrickling filter performance degrading chlorobenzene and o-dichlorobenzene mixture were studied. The large laboratory scale biofilter, total volume 40 L, filled with inert packing material was used. The biomass adaptation and cultivation were performed in a batch fermentor and were used to inoculate the biotrickling filter. After a starting period, the influence of the substrate load increase, liquid recirculation flow rate, and empty bed retention time on elimination capacity and removal efficiency were found. The most important recirculation liquid parameters were analyzed every day, that is: concentration of metabolites, dissolved organic carbon, nitrate, chloride, and biomass. A good correlation was found between intermediate concentration and the removal efficiency of the biotrickling filter. The measurements of the absorbance, very easy and rapid, can be used as a control parameter of the biofiltration efficiency.