The effects of numerical resolution on hydrodynamical surface convection simulations and spectral line formation

The computationally demanding nature of radiative-hydrodynamical simulations of stellar surface convection warrants an investigation of the sensitivity of the convective structure and spectral synthesis to the numerical resolution and dimension of the simulations, which is presented here. With too coarse a resolution the predicted spectral lines tend to be too narrow, reflecting insufficient Doppler broadening from the convective motions, while at the currently highest affordable resolution the line shapes have converged essentially perfectly to the observed profiles. Similar conclusions are drawn from the line asymmetries and shifts. In terms of abundances, weak FeI and FeII lines show a very small dependence (~0.02 dex) while for intermediate strong lines with significant non-thermal broadening the sensitivity increases (~0.10 dex). Problems arise when using 2D convection simulations to describe an inherent 3D phenomenon, which translates to inaccurate atmospheric velocity fields and temperature and pressure structures. In 2D the theoretical line profiles tend to be too shallow and broad compared with the 3D calculations and observations, in particular for intermediate strong lines. In terms of abundances, the 2D results are systematically about 0.1 dex lower than for the 3D case for FeI lines. Furthermore, the predicted line asymmetries and shifts are much inferior in 2D. Given these shortcomings and computing time considerations it is better to use 3D simulations of even modest resolution than high-resolution 2D simulations.Comment: Accepted for A&

Studies on the Effects of Ammonium Phosphates on the Flammability Properties of Poly(Vinyl Alcohol) Films

Poly(vinyl alcohol) was solvent-cast from aqueous solution of n-hexane into 125 μm films. Three ammonium phosphates, (NH4)3PO4, NH4H2PO4 and (NH4)2HPO4, were then added to produce eight sample films. Burning time, flame spread, limiting oxygen index, ignition time, and afterglow time of the samples were evaluated to determine the flame retardant efficiency of the three fillers. From the results, burning time, flame spread, after-glow time, and ignition response indices of the filled samples were found to be lower than the control sample. However, limiting oxygen index of the filled samples was found to be higher than that of the control sample. The efficiency of the fillers in fireproofing the poly(vinyl alcohol) film was found to follow the order (NH4)3PO4 > NH4H2PO4 > (NH4)2HPO4. Additive effect was observed when the fillers are added in pairs with the fireproofing efficiency following the order (NH4)3PO4 + NH4H2PO4 > (NH4)3PO4 + (NH4)2HPO4 > (NH4)2HPO4 + NH4H2PO4. Antagonism in fireproofing efficiency was observed when all the three fillers were present in the poly(vinyl alcohol) film. The fireproofing efficiency of the ammonium salts is attributed to the quantity and the ease with which ammonia (NH3) gas is released when the filled poly(vinyl alcohol) films were heated

Sparticle Spectrum Constraints

The supersymmetric standard model with supergravity-inspired soft breaking terms predicts a rich pectrum of sparticles to be discovered at the SSC, LHC and NLC. Because there are more supersymmetric particles than unknown parameters, one can write down sum rules relating their masses. We discuss the pectrum of sparticles from this point of view. Some of the sum rules do not depend on the input parameters and can be used to test the consistency of the model, while others are useful in determining the input parameters of the theory. If supersymmetry is discovered but the sum rules turn out to be violated, it will be evidence of new physics beyond the minimal supersymmetric standard model with universal soft supersymmetry-breaking terms.Comment: 25 pages. NUB-3067-93TH, UFIFT-HEP-93-16, SSCL-Preprint-439, June 199

Volume and Volatility in the FX-Market: Does it matter who you are?

The relationship between volume and volatility has received much attention in the the literature of financial markets. However, due to the lack of data, few results have been presented for the foreign exchange market. Further, most studies contain only aggregate series, and can not distinguish between the impact of different instruments or participants.We study the impact of volume on volatility in the the FX-market using a unique data set of daily trading in the Swedish krona (SEK) market. The data set covers 95 per cent of worldwide SEK-trading, and is disaggregated on a number of reporting banks’ buying and selling in five different instruments on a daily basis over a period of nine years. We find that volume in general depict a positive correlation with volatility. However, the strength of the relationship depends on the instrument used and the identity of the reporting bank. In particular we find that it is the large Swedish banks that dominate the relationship. These banks are probably also the best informed banks. We interpret this is as evidence that heterogeneous expectations are important to understand the volume-volatility relationship.volume volatility relation, microstructure, exchange rates.

Investigation of electrical properties for cantilever-based piezoelectric energy harvester

In the present era, the renewable sources of energy, e.g., piezoelectric materials are in great demand. They play a vital role in the field of micro-electromechanical systems, e.g., sensors and actuators. The cantilever-based piezoelectric energy harvesters are very popular because of their high performance and utilization. In this research-work, an energy harvester model based on a cantilever beam with bimorph PZT-5A, having a substrate layer of structural steel, was presented. The proposed energy scavenging system, designed in COMSOL Multiphysics, was applied to analyze the electrical output as a function of excitation frequencies, load resistances and accelerations. Analytical modeling was employed to measure the output voltage and power under pre-defined conditions of acceleration and load resistance. Experimentation was also performed to determine the relationship between independent and output parameters. Energy harvester is capable of producing the maximum power of 1.16 mW at a resonant frequency of 71 Hz under 1g acceleration, having load resistance of 12 k Omega. It was observed that acceleration and output power are directly proportional to each other. Moreover, the investigation conveys that the experimental results are in good agreement with the numerical results. The maximum error obtained between the experimental and numerical investigation was found to equal 4.3%

Perception Factors, Intentions and Attitudes with Market Community Participation to Prevent Occupational Diseases

An Occupational Disease was a disease caused by work or work environment. One of the efficient and effective strategies for controlling Occupational Disease was the empowerment and participation of the community called Occupational Health Unit (Pos UKK) in the workplace. Based on the data of market health inspection in Pos UKK Imogiri market in March 2017, there were only 67 participants (19.17%) from 365 invited people.: The purpose of this research was to know the internal factors with the community participation in Pos UKK Imogiri market Bantul. This research was a quantitative analytic research with cross sectional design. The population was 365 people and the sample was 150 respondents. The sampling used purposive sampling technique. Kendall Tau test showed that there was a relation between perception and community participation (p value <0.05, r = 0.677); Intentions related to community participation (p value <0.05 r = 0.486); Attitudes related to community participation (p value <0.05 , r= 0.802). F test result showed that the variables of Perception, Intentions and Attitudes related simultaneously to community participation (F value = 387.41> F table = 2.67). The dominant independent variable was Attitudes with the highest Standard Beta Coefficient value was 0.776. Perceptions, Intentions and Attitudes related both partially and simultaneously to community participation; the independent variable that had dominant influence was Attitudes

Case Report Rhinosinusitis; A Potential hazard of Nasogastric tube insertion

The nasogastric tube has been used frequently for enteral feeding and as anintranasal oxygen catheter. This practice is however associated with complications. We present a case of rhinosinusitis and sepsis in a diabeticpatient following the insertion of a nasogastric tube. Physicians should be aware of sinusitis as a possible cause of sepsis in patients with nasogastric tube insertion.Key words: Rhinosinusitis, Nasogastric Tub

Electron Glass Dynamics

Examples of glasses are abundant, yet it remains one of the phases of matter whose understanding is very elusive. In recent years, remarkable experiments have been performed on the dynamical aspects of glasses. Electron glasses offer a particularly good example of the 'trademarks' of glassy behavior, such as aging and slow relaxations. In this work we review the experimental literature on electron glasses, as well as the local mean-field theoretical framework put forward in recent years to understand some of these results. We also present novel theoretical results explaining the periodic aging experiment.Comment: Invited review to appear in Annual Review of Condensed Matter Physic

Sediment-moss interactions on a temperate glacier: Falljökull, Iceland

Full text of this article can be found at: http://www.igsoc.org/annals/ Copyright IGS. DOI: 10.3189/172756408784700734We present the results of preliminary investigations of globular moss growth on the surface of Falljökull, a temperate outlet glacier of the Vatnajökull ice cap, southern Iceland. Supraglacial debris has provided a basis for moss colonization, and several large (>500 m2) patches of moss growth (Racomitrium spp.) are observed on the surface of the glacier. Each area of moss-colonized supraglacial debris shows a downslope increase in sphericity and moss cushion size and a decrease in percentage surface coverage of moss-colonized and bare clasts. It is suggested that moss growth on supraglacial debris allows preferential downslope movement of clasts through an associated increase in both overall mass and sphericity. Thermal insulation by moss cushions protects the underlying ice surface from melt, and the resulting ice pedestals assist in downslope sliding and toppling of moss cushions. The morphology and life cycle of supraglacial globular mosses is therefore not only closely linked to the presence and distribution of supraglacial debris, but also appears to assist in limited down-glacier transport of this debris. This research highlights both the dynamic nature of the interaction of mosses with supraglacial sedimentary systems and the need for a detailed consideration of their role within the wider glacial ecosystem.Peer reviewe