Atmospheric corrosion of reference metals in Antarctic sites

This paper presents the results obtained at three Antarctic test sites participating in the “Ibero-American Map of Atmospheric Corrosiveness” (MICAT), a project on atmospheric corrosion carried out during the period 1988–1994 at some 70 sites distributed across 12 countries of the Latin-American region, Spain and Portugal. The three Antarctic sites are located near the coastline.The singular climatic characteristics of Antarctic regions are related with the purity of the air, the absence of rainfall and the formation of ice on the metallic surface during an important part of the exposure time. However, electrochemical activity is possible below ice layers. This situation affects the structure and morphology of corrosion product films and the resulting corrosion rates of metallic surfaces.     

Synthesis and characterization of functional gradient copolymers of glycidyl methacrylate and butyl acrylate

Epoxy-functional spontaneous gradient copolymers of glycidyl methacrylate (G) and n-butyl acrylate (B) were synthesized via atom transfer radical polymerization (ATRP). The copolymerization reactions were carried out in toluene solution at 70 °C, using methyl 2-bromopropionate (MBrP) as initiator and copper chloride with N,N,N′,N′′,N′′-pentamethyldiethylenetriamine (PMDETA) as the catalyst system. The kinetic behaviour of the statistical copolymerizations was studied in a wide composition interval with molar fractions of G ranging from 0.10 to 0.75. The synthesized copolymers were characterized by size exclusion chromatography (SEC) and nuclear magnetic resonance (NMR) spectroscopy. ¹H NMR was employed to determine the copolymer composition, demonstrating the gradient character of the copolymers along the main chain in the whole monomer conversion interval. Apart from this, the sequence distribution and stereoregularity were analyzed. These microstructural experimental data agreed well with those calculated from Mayo-Lewis terminal model (MLTM) and a Bernoullian statistic with an isotacticity parameter of σ_G = 0.28 and a coisotacticity parameter of σ = 0.30.     

Spatial soliton-induced guiding by cross-phase modulation

The authors show that spatial solitons are able to induce the stable guiding of a weak probe beam in a homogeneous Kerr-type nonlinear media through cross-phase modulation (XPM). The modes of the induced waveguide are derived from the propagation equation of the probe. Experiments have been performed in Kerr liquid CS₂, with beams of picosecond duration at infrared and visible wavelengths. Stable guiding of a green probe induced by an IR soliton beam has been demonstrated in several different experimental situations. Induced antiguiding and beam splitting are also reported for pump and probe of perpendicular polarizations. All results are in excellent agreement with numerical simulations of the propagation     

Electrospun fibers based on porcine plasma: a rheological and morphological study

Iranian Polymer Journal - The present work focuses on the assessment of the ability of porcine plasma protein (PPP) to be electrospun satisfactorily to form fibre mats, and their rheological and...     

POWER CONSUMPTION WITH ANCHOR MIXERS EFFECT OF BOTTOM CLEARANCE

The effect of bottom clearance on power draw for anchors is investigated. The results suggest that power input decreases as the bottom clearance ratio b/D increases. A new correlation is proposed in which both bottom and wall clearance effects on power input are considered. The dependence of power input on these effects is additive rather than multiplicative. Thus, the total power consumption is the sum of the power inputs generated by the wall and bottom clearance. Power results from 3D-CFD numerical simulations are also presented. These results confirm fairly well the experimental points.     

The effectiveness of the combined use of VIX and Support Vector Machines on the prediction of S&P 500

The aim of this research is to analyse the effectiveness of the Chicago Board Options Exchange Market Volatility Index (VIX) when used with Support Vector Machines (SVMs) in order to forecast the weekly change in the S&P 500 index. The data provided cover the period between 3 January 2000 and 30 December 2011. A trading simulation is implemented so that statistical efficiency is complemented by measures of economic performance. The inputs retained are traditional technical trading rules commonly used in the analysis of equity markets such as Relative Strength Index, Moving Average Convergence Divergence, VIX and the daily return of the S&P 500. The SVM identifies the best situations in which to buy or sell in the market. The two outputs of the SVM are the movement of the market and the degree of set membership. The obtained results show that SVM using VIX produce better results than the Buy and Hold strategy or SVM without VIX. The influence of VIX in the trading system is particularly significant when bearish periods appear. Moreover, the SVM allows the reduction in the Maximum Drawdown and the annualised standard deviation.     

Functionalization of carbon support and its influence on the electrocatalytic behaviour of Pt/C in H2 and CO electrooxidation

Chemical modification of Carbon Vulcan XC-72R for fuel cell applications has been undertaken. Treated carbons were used as carriers for the deposition of Pt nanoparticles and used as electrocatalysts. The influence of the carbon treatment, as well as that of the Pt nanoparticles generation and their deposition route has been studied. The behaviour of the electrocatalysts in the CO and hydrogen oxidation reaction (HOR) has been studied. It was observed that carbon pre-treatment lead to difference behaviour in the CO oxidation reaction compared with the performance over non treated supports. In this way, CO oxidation was controlled by the nature of the support rather than by the nature of the Pt particles alone.     

Linking the proteins--elucidation of proteome-scale networks using mass spectrometry

Proteomes are intricate. Typically, thousands of proteins interact through physical association and post-translational modifications (PTMs) to give rise to the emergent functions of cells. Understanding these functions requires one to study proteomes as "systems" rather than collections of individual protein molecules. The abstraction of the interacting proteome to "protein networks" has recently gained much attention, as networks are effective representations, that lose specific molecular details, but provide the ability to see the proteome as a whole. Mostly two aspects of the proteome have been represented by network models: proteome-wide physical protein-protein-binding interactions organized into Protein Interaction Networks (PINs), and proteome-wide PTM relations organized into Protein Signaling Networks (PSNs). Mass spectrometry (MS) techniques have been shown to be essential to reveal both of these aspects on a proteome-wide scale. Techniques such as affinity purification followed by MS have been used to elucidate protein-protein interactions, and MS-based quantitative phosphoproteomics is critical to understand the structure and dynamics of signaling through the proteome. We here review the current state-of-the-art MS-based analytical pipelines for the purpose to characterize proteome-scale networks.     

Evaluation of a new computer-assisted surgical planning and navigation system based on two-dimensional fluoroscopy for insertion of a proximal femoral nail: an experimental study

Pertrochanteric femoral fractures are common and intramedullary nailing is an accepted method for their surgical treatment. Accurate placement of the implant is essential to ensure fixation. The conventional technique can require multiple guide wire passes, and relies heavily on fluoroscopy. A computer-assisted planning and navigation system based on two-dimensional fluoroscopy for guide wire placement in the femoral neck has been developed, in order to perform intramedullary pertrochanteric fracture fixation using the proximal femoral nail (PFNA). The planning process was supported by a 'zero-dose C-arm navigation' system. The PFNA was inserted into 12, intact, femoral sawbones guided by the computer-based navigation, and into 12, intact, femoral sawbones using a conventional fluoroscopic-assisted technique. Guide wire and subsequent blade placement in the femoral neck was evaluated. The computer-assisted technique achieved a significant decrease in the number of required fluoroscopic images and in the number of guide wire passes. The obtained average blade placement accuracy in the femoral neck was equivalent to the conventional technique. The operation time was significantly longer in the navigation-assisted group. The addition of computer-assisted planning and surgical guidance to the intramedullary nailing of pertrochanteric femoral fractures offers a number of clinical benefits based on the results of this sawbone study. Further studies including fractured sawbones and cadaver models with extension of the navigation process to all steps of PFNA introduction and with the goal of reducing operation time are indispensable before integration of this navigation system into clinical practice.