Build Time Estimations for Large Scale Modelling

Achieving speedy results in model making is very much desired if not a necessity in ahnost any manufacturing industry. There is no doubt that rapid prototyping contributes to this process. It is generally considered that when compared to conventional machining techniques like nlilling, the current rapid prototyping systems appear to be much faster. This is certainly true for complex,slnall objects. I-Iowever, this is not alwaysa,pplicable to simple, large and bulky parts. There are a number of projects and systems concentrating on the fabrication of large models. Work is being carried out at the University ofHong Kong, using milling. along with slicing technology. This.report compares some ofthe rapid prototyping systems witl1milling. Milling is an established technology and recent developments in materials and nlachines used in Inilling nlake it a good alternative to rapid prototyping when itcomes to largesyale nl0delling.Mechanical Engineerin

The Impact of Professional Sports on Cities’ Economic Performance

The purpose of this paper is to estimate the impact of professional sports on cities’ economic performance as measured by real per capita income growth and changes in the unemployment rate. We use a panel model across 43 cities over eight years. Explanatory variables include the number of professional sports franchises in a city and the performance of those franchises. We find no statistically significant evidence suggesting that professional sports franchises impact cities’ real per capita income growth. We do, however, find that professional sports franchises have a statistically significant impact on unemployment rates

Theoretical investigations of r-f induction heated plasmas

Radio frequency induction heated plasmas with power deposition and energy remova

Experimental investigations of heavy-gas containment in r-f heated and unheated two- component vortexes

Heavy gas concentration in light gas vortices for heated and unheated vortex flow

Experimental investigation of the spectral emission characteristics of argon-tungsten and argon-uranium induction heated plasmas

Spectral emission characteristics of gaseous tungsten and uranium in induction heated argon plasma

Containment experiments in vortex tubes with radial outflow and large superimposed axial flows

Containment tests of vortexes with radial outflow in basic vortex tube, and in axial-flow vortex tub

Hydrochemical determination of source water contributions to Lake Lungo and Lake Ripasottile (central Italy)

Lake Lungo and Lake Ripasottile are two shallow (4-5 m) lakes located in the Rieti Basin, central Italy, that have been described previously as surface outcroppings of the groundwater table. In this work, the two lakes as well as springs and rivers that represent their potential source waters are characterized physio-chemically and isotopically, using a combination of environmental tracers. Temperature and pH were measured and water samples were analyzed for alkalinity, major ion concentration, and stable isotope (δ2H, δ18O, δ13C of dissolved inorganic carbon, and δ34S and δ18O of sulfate) composition. Chemical data were also investigated in terms of local meteorological data (air temperature, precipitation) to determine the sensitivity of lake parameters to changes in the surrounding environment. Groundwater represented by samples taken from Santa Susanna Spring was shown to be distinct with SO4 2- and Mg2+ content of 270 and 29 mg/L, respectively, and heavy sulfate isotopic composition (δ34S=15.2‰ and δ18O=10‰). Outflow from the Santa Susanna Spring enters Lake Ripasottile via a canal and both spring and lake water exhibits the same chemical distinctions and comparatively low seasonal variability. Major ion concentrations in Lake Lungo are similar to the Vicenna Riara Spring and are interpreted to represent the groundwater locally recharged within the plain. The δ13CDIC exhibit the same groupings as the other chemical parameters, providing supporting evidence of the source relationships. Lake Lungo exhibited exceptional ranges of δ13CDIC (±5‰) and δ2H, δ18O (±5 ‰ and ±7 ‰, respectively), attributed to sensitivity to seasonal changes. The hydrochemistry results, particularly major ion data, highlight how the two lakes, though geographically and morphologically similar, represent distinct hydrochemical facies. These data also show a different response in each lake to temperature and precipitation patterns in the basin that may be attributed to lake water retention time. The sensitivity of each lake to meteorological patterns can be used to understand the potential effects from long-term climate variability

Poly(di(ω-alkylphenyl)stannane)s

Poly(di(ω-alkylphenyl)stannane)s, [Sn(C n H2n Ph)2] m with n=2-4, and a copolymer of di(3-propylphenyl)stannane and dibutylstannane of weight-average molar masses of 2-8·104g/mol were synthesized by dehydropolymerization of stannanes of the composition H2SnR2 using Wilkinson's catalyst [RhCl(PPh3)3]. At least two methylene groups were required as spacers between the phenyl group and the tin atom for polymerization to occur. The polystannanes were characterized by, among other techniques, 1H, 13C and 119Sn NMR spectroscopy, thermal analysis and X-ray diffraction. The polymers featured properties different from those of the corresponding poly(dialkylstannane)s. Specifically, the [Sn(C n H2n Ph)2] m family displayed glass transitions at remarkably low temperatures, down to ca. −50°C, and a lower value for a copolymer (−68°C). Polymers [Sn(CnH2nPh)2]m with n=2 and 3 and a copolymer at room temperature were of a gel-like concistence, which enabled facile orientation with shear forces. Finally, the temperature-dependent electrical conductivity was determined for poly(di(3-propylphenyl)stannane), which followed the law of typical semiconductors, with an activation energy for conduction of 0.12e