Diagnosis of tool wear based on cutting forces and acoustic emission measures as inputs to a neural network

Cutting forces and acoustic emission measures as a function of tool wear are presented for different cutting parameters and their applicability for tool condition monitoring is evaluated. The best of them, together with cutting parameters, were chosen as inputs to a feedforward, back propagation (FFBP) neural network; some training techniques were applied and their effectiveness is also evaluated. Conventional training of FFBP neural networks very soon leads to overtraining, hence to deterioration in the net response. Training of these nets depends very much on the initial weight values. A good way of finding satisfactory results is to introduce random distortions to the weight system, which efficiently push the net out of a local minimum of testing errors. An even more effective method may be to employ temporary shifts in the weights, alternately negative and positive. This has two advantages: (1) it brings the net to balance between training and testing errors and (2) it enables a great reduction in the number of hidden nodes.     

In silico identification, structure prediction and phylogenetic analysis of the 2'-O-ribose (cap 1) methyltransferase domain in the large structural protein of ssRNA negative-strand viruses

The Escherichia coli RrmJ gene product has recently been shownto be the 23S rRNA:U2552 specific 2'-O-ribose methyltransferase(MTase) (RrmJ). Its structure has been solved and refined to1.5 Å resolution, demonstrating conservation of the three-dimensionalfold and key catalytic side chains with the vaccinia virus VP39protein, which functions as an mRNA 5'm⁷G-cap-N-specific 2'-O-riboseMTase. Using the amino acid sequence of RrmJ as an initial probein an iterative search of sequence databases, we identifieda homologous domain in the sequence of the L protein of non-segmented,negative-sense, single-stranded RNA viruses. The plausibilityof the prediction was confirmed by homology modeling and checkingwhether important residues at substrate/ligand-binding siteswere conserved. The predicted structural compatibility and theconservation of the active site between the novel putative MTasedomain and genuine 2'-O-ribose MTases, together with the availableresults of biochemical studies, strongly suggest that this domainis a 5'm⁷G-cap-N-specific 2'-O-ribose MTase (i.e. the cap 1MTase). Evolutionary relationships between these proteins arealso discussed.     

Well-defined core-shell structures based on silsesquioxane microgels: Grafting of polystyrene via ATRP and product characterization

Silsesquioxane microgel nanoparticles characterized by low diameters (below 30 nm) and reduced polydispersity can be produced in an acid-catalyzed sol-gel process in an aqueous microemulsion. Suitable surface modification of such structures leads to macroinitiators for atom-transfer radical polymerization (ATRP). This polymerization method was applied in order to graft polystyrene chains onto the surface of the microgels. Well-defined structures exhibiting a core-shell architecture were produced with the M_w of grafted polymers ranging from 8.5 to about 30 kg/mol. The products were extensively characterized with light scattering, X-ray scattering, thermal analysis (TGA/DSC) and microscopy (TEM/SEM) to obtain information on parameters characterizing polystyrene brush. Polymer-grafted nanoparticles will be used for the modification of homopolymer and block copolymer matrices.     

A 3-D hp finite/infinite element method to calculate power deposition in the human head

The electromagnetic power deposition and transfer properties of a G1 continuous head model reconstructed from magnetic resonance imaging (MRI) data are investigated by using the coupled hp finite/infinite element (FE/IE) method. The discretization error is controlled by a self-adaptive process driven by an explicit a posteriori error estimate. Based on the benchmark problem of reproducing the Mie series solution, the scattering of a plane wave on the curvilinear head model is used to evaluate the hp FE/IE approach and calibrate the error bound. The radiation pattern from a short dipole antenna modeling a cell phone, is analyzed in terms of the level and distribution of the specific absorption rates (SAR). The numerical experiments show that the hybrid hp FE/IE implementation is a competitive tool for accurate assessment of human electromagnetic exposure.     

Integrated seismic and magnetotelluric exploration of the Skierniewice,Poland, geothermal test site

The purpose of the research activities at the Skierniewice geothermal test site is to develop and apply an exploration methodology for low-enthalpy systems in sedimentary formations. Work included seismic and magnetotelluric surveys carried out close to well Kompina-2 to create a detailed structural–geologic model and characterize the anisotropic fracture system around the borehole. The study included the reprocessing of archival data from selected boreholes and 2D seismic lines. The collected data were used to identify formations with high fracture permeability and the presumed flow path of geothermal (∼110 °C) brine in high productivity zones, and determining rock porosities and salinity distribution in the subsurface. The next stage of the investigations will focus on siting a second borehole and studying the possibility of installing a plant for electrical generation or direct geothermal heat applications.     

The effect of n-alcohols on porous anodic alumina formed by self-organized two-step anodizing of aluminum in phosphoric acid

Self-ordered porous anodic alumina films were fabricated by a two-step anodization technique at potentials between 110 and 170 V using different n-alcohols and water mixtures containing 0.3 M H₃PO₄ at the electrolyte temperatures of 0 and − 5 °C. The morphology of the specimens was observed by a field emission scanning electron microscope (FE-SEM). Anodic aluminum oxide (AAO) films fabricated in the absence of n-alcohols exhibit a complex structure with sub-pores, independently of the anodizing potential. The sub-pore structure of films disappeared in the presence of n-alcohols probably due to the cooling effect of alcohol and extended time for the pore interaction (re-arrangement of pores). Additionally, with increasing anodizing potential, the regularity of pore arrangement, uniformity of pore shape and interpore distance of the AAO film increases independently of the electrolyte composition. The order of arrangement and circular shape of pores increases with increasing n-alcohol content for both anodizing temperatures. The best arranged porous structures were obtained in 1:1 methanol-water electrolyte containing 0.3 M H₃PO₄ (lower evaporating point than n-propanol and water) at 0 °C. The interpore distance of porous anodic alumina decreases with increasing n-alcohol content and increasing regularity of pore arrangement.     

Levoglucosan and other cellulose markers in pyrolysates of Miocene lignites: geochemical and environmental implications

Using the pyrolysis-gas chromatography-mass spectrometry and off-line pyrolysis/silylation methods for lignites from three Miocene brown coal basins of Poland resulted in the characterization of many organic compounds, including dominant cellulose degradation products such as levoglucosan, 1,6-anhydro-beta-D-glucofuranose, and 1,4:3,6-dianhydroglucopyranose. Levoglucosan is a general source-specific tracer for wood smoke in the atmosphere and recent sediments. The presence of unusually high levels of this compound in brown coal pyrolysates suggests that a portion of this compound concentration in some airsheds may originate from lignite combustion. On the other hand, nonglucose anhydrosaccharides, in particular, mannosan and galactosan, typical of hemicellulose, are not detected in those lignite pyrolysates investigated. This indicates that mannosan and galactosan are better specific tracers for combustion of contemporary biomass in those regions were the utilization of brown coals containing fossilized cellulose is important.     

Emission characteristics and stability of laser ion sources

A new classification of laser ion sources concerning their pulse-to-pulse reproducibility in the ion emission is proposed. In particular, we distinguish between plasmas according to the electron distribution and changing its characteristics at a laser intensity threshold of 10¹⁴ W/cm². Well reproducible continuous pulsed ion currents are typical for the intensity below the threshold. In contrast to this plasma the “two-temperature” plasma arising for the intensity above this threshold shows not only a separation of charges in space and time during the expansion but it also shows outbursts of ions similar to a self-pulsing instability leading to a chaos. The sequence of fast ion outbursts visible on the time-resolved ion currents is sensitive to the details of non-linear interaction of the laser beam with the generated plasma.Analysis of ion sources based on a time-of-flight signal function is applied to quantify their emission characteristics as the hidden partial currents of the ionized species constituting, the total measured current, the centre-of-mass velocity of individual charge states, their abundance and the ion temperature.     

In Silico Modeling of the Influence of Environment on Amyloid Folding Using FOD-M Model

The role of the environment in amyloid formation based on the fuzzy oil drop model (FOD) is discussed here. This model assumes that the hydrophobicity distribution within a globular protein is consistent with a 3D Gaussian (3DG) distribution. Such a distribution is interpreted as the idealized effect of the presence of a polar solvent—water. A chain with a sequence of amino acids (which are bipolar molecules) determined by evolution recreates a micelle-like structure with varying accuracy. The membrane, which is a specific environment with opposite characteristics to the polar aquatic environment, directs the hydrophobic residues towards the surface. The modification of the FOD model to the FOD-M form takes into account the specificity of the cell membrane. It consists in “inverting” the 3DG distribution (complementing the Gaussian distribution), which expresses the exposure of hydrophobic residues on the surface. It turns out that the influence of the environment for any protein (soluble or membrane-anchored) is the result of a consensus factor expressing the participation of the polar environment and the “inverted” environment. The ratio between the proportion of the aqueous and the “reversed” environment turns out to be a characteristic property of a given protein, including amyloid protein in particular. The structure of amyloid proteins has been characterized in the context of prion, intrinsically disordered, and other non-complexing proteins to cover a wider spectrum of molecules with the given characteristics based on the FOD-M model.