Poisson Shot Noise Removal by an Oracular Non-Local Algorithm

Journal of Mathematical Imaging and Vision - In this paper, we address the problem of denoising images obtained under low-light conditions for the Poisson shot noise model. Under such conditions,...     

Oxidation behavior of copper at high temperatures under two different modes of direct-current applications

Oxidation kinetics of copper in the temperature range of 973–1173 K atP _{O 2}=21.27 kPa exhibit enhancement and deceleration in the rates with changing polarity compared to normal oxidation under interrupted mode of directcurrent application. These conditions are achieved by connecting the oxidizing copper covered with an initially formed thin oxide film to the positive and negative terminal of a dc source, respectively. However, the influence of direction of the current is found to be opposite under uninterrupted mode of impressed current flow in the same temperature range. The effect of short-circuiting the metal to the outer oxide/air interface on the reaction kinetics is also reported. The rate of oxide-scale growth under normal condition, and two different modes of current applications as well as with shorting circuitry attachment conform to the parabolic growth law. The results pertaining to the two different modes of impressed current have been discussed considering both the phenomena of electrolysis of the oxide electrolyte and the polarization at the two phase boundaries. The enhancement and the reduction in rates under uninterrupted impressed current conditions are explained on the basis of increased and decreased average defect concentrations, respectively, within the oxide layer. The acceleration and deceleration in the rates under interrupted mode of current flow have been explained in the light of sustenance of a steeper and flatter electrochemical-potential gradient of defects, respectively, across the growing-oxide layer. The possible different responses of the metal/oxide and oxide/air interfaces to the impressed current brought into play by two different modes of current application, have enabled to display a better insight on the mechanistic aspects of scale growth under the influence of an externally applied current.     

Inkjet‐Printed Lithium–Sulfur Microcathodes for All‐Printed,Integrated Nanomanufacturing

Improved thin‐film microbatteries are needed to provide appropriate energy‐storage options to power the multitude of devices that will bring the proposed “Internet of Things” network to fruition (e.g., active radio‐frequency identification tags and microcontrollers for wearable and implantable devices). Although impressive efforts have been made to improve the energy density of 3D microbatteries, they have all used low energy‐density lithium‐ion chemistries, which present a fundamental barrier to miniaturization. In addition, they require complicated microfabrication processes that hinder cost‐competitiveness. Here, inkjet‐printed lithium–sulfur (Li–S) cathodes for integrated nanomanufacturing are reported. Single‐wall carbon nanotubes infused with electronically conductive straight‐chain sulfur (S@SWNT) are adopted as an integrated current‐collector/active‐material composite, and inkjet printing as a top‐down approach to achieve thin‐film shape control over printed electrode dimensions is used. The novel Li–S cathodes may be directly printed on traditional microelectronic semicoductor substrates (e.g., SiO₂) or on flexible aluminum foil. Profilometry indicates that these microelectrodes are less than 10 µm thick, while cyclic voltammetry analyses show that the S@SWNT possesses pseudocapacitive characteristics and corroborates a previous study suggesting the S@SWNT discharge via a purely solid‐state mechanism. The printed electrodes produce ≈800 mAh g^?1 S initially and ≈700 mAh g^?1 after 100 charge/discharge cycles at C/2 rate.     

PLISS: labeling places using online changepoint detection

A shared vocabulary between humans and robots for describing spatial concepts is essential for effective human robot interaction. Towards this goal, we present a novel technique for place categorization from visual cues called PLISS (Place Labeling through Image Sequence Segmentation). PLISS is different from existing place categorization systems in two major ways—it inherently works on video and image streams rather than single images, and it can detect “unknown” place labels, i.e. place categories that it does not know about. PLISS uses changepoint detection to temporally segment image sequences which are subsequently labeled. Changepoint detection and labeling are performed inside a systematic probabilistic framework. Unknown place labels are detected by using a probabilistic classifier and keeping track of its label uncertainty. We present experiments and comparisons on the large and extensive VPC dataset. We also demonstrate results using models learned from images downloaded from Google’s image search.     

An insight into spray pulsed reactor through mathematical modeling of catalytic dehydrogenation of cyclohexane

A mathematical model has been developed to study the impact of nozzle-catalyst distance and bulk gas temperature on the conversion and hydrogen evolution rate in a spray pulse reactor. The effects of reactor configuration and operating parameters on conversion and evolution rate were predicted with more than 90% accuracy. Reactor optimization and sensitivity analysis were carried out and an optimal design of nozzle-catalyst distance 5 cm and bulk gas temperature of 50 °C were proposed. The optimized design was predicted to increase the conversion from approximately 32–74%. The model could be in general used for designing any endothermic heterogeneous catalytic reaction in a spray pulse reactor.     

Novel 1,3,4-oxadiazole derivatives as efficient sensitizers for dye-sensitized solar cells: A combined experimental and computational study

We have synthesized and characterized donor–π–spacer–acceptor type molecules in which 1,3,4-oxadiazoles are π-spacers, triphenylamines are the donors and cyanoacetic acid are the acceptors for use as sensitizers in dye-sensitized solar cells (DSSCs). Detailed absorption, emission, electrochemical, photoelectrochemical and computational studies have been carried out on five novel derivatives. The dyes have an absorption range of 377–388 nm, and an emission in the range of 494–540 nm. There is a large charge transfer from the donor side to the acceptor side on excitation. The propeller shape of the triphenylamine and the bulky substituents on it help in reducing the dye-aggregation on TiO₂ surface. The dyes exhibited good overall conversion efficiency (2.79–3.21%). Plane wave calculations indicate that the dye has a reasonably strong binding to the TiO₂ surface and the generated DOS picture shows an overlap of the molecular orbitals of the dye and the TiO₂ bands. We conclude that the dyes have a promising role as sensitizers in DSSC.     

New Poly(N-isopropylacrylamide-butylacrylate) Copolymer Biointerfaces and Their Characteristic Influence on Cell Behavior In Vitro

Designing and obtaining new synthetic smart biointerfaces with specific and controlled characteristics relevant for applications in biomedical and bioengineering domains represents one of the main challenges in these fields. In this work, Matrix-Assisted Pulsed Laser Evaporation (MAPLE) is used to obtain synthetic biointerfaces of poly(N-isopropyl acrylamide-butyl acrylate) p(NIPAM-BA) copolymer with different characteristics (i.e., roughness, porosity, wettability), and their effect on normal HEK 293 T and murine melanoma B16-F1 cells is studied. For this, the influence of various solvents (chloroform, dimethylsulfoxide, water) and fluence variation (250–450 mJ/cm²) on the morphological, roughness, wettability, and physico–chemical characteristics of the coatings are evaluated by atomic force microscopy, scanning electron microscopy, contact angle measurements, Fourier-transform-IR spectroscopy, and X-ray photoelectron spectroscopy. Coatings obtained by the spin coating method are used for reference. No significant alteration in the chemistry of the surfaces is observed for the coatings obtained by both methods. All p(NIPAM-BA) coatings show hydrophilic character, with the exception of those obtained with chloroform at 250 mJ/cm². The surface morphology is shown to depend on both solvent type and laser fluence and it ranges from smooth surfaces to rough and porous ones. Physico–chemical and biological analysis reveal that the MAPLE deposition method with fluences of 350–450 mJ/cm² when using DMSO solvent is more appropriate for bioengineering applications due to the surface characteristics (i.e., pore presence) and to the good compatibility with normal cells and cytotoxicity against melanoma cells.     

Influence of DLC coating thickness on tribological characteristics under sliding rolling contact condition

Diamond-like-carbon (DLC) coating of thickness 3 and 10 μm were developed with and without radical nitriding pretreatment on steel rollers and spur gear pair. The friction coefficient and wear amount were evaluated under sliding rolling contact condition in vacuum and under oil lubrication. Delamination of coatings was observed at the interface of the substrate. The wear resistance of coatings improved with the thickness of the coating. In vacuum both the roller and the gear pair of 10 μm coating thickness with radical nitriding showed identical wear behavior. The radical nitriding seemed to enhance the life of DLC coatings.     

Polymerization shrinkage and porosity profile of dual cure dental resin cements with different adhesion to dentin mechanisms

This research aims to probe the porosity profile and polymerization shrinkage of two different dual cure resin cements with different dentin bonding systems. The self‐adhesive resin cement RelyX U200 (named RU) and the conventional Allcem Core (named AC) were analyzed by x‐ray microtomography (μCT) and Scanning Electron Microscopy (SEM). Each cement was divided into two groups (n = 5): dual‐cured (RUD and ACD) and self‐cured (RUC and ACC). μCT demonstrated that the method of polymerization does not influence the porosity profile but the polymerization shrinkage. Fewer concentration of pores was observed for the conventional resin cement (AC), independently the method used for curing the sample. In addition, SEM showed that AC has more uniform surface and smaller particle size. The method of polymerization influenced the polymerization shrinkage, since no contraction for both RUC and ACC was observed, in contrast with results from dual‐cured samples. For RUD and ACD the polymerization shrinkage was greater in the lower third of the sample and minor in the upper third. This mechanical behavior is attributed to the polymerization toward the light. µCT showed to be a reliable technique to probe porosity and contraction due to polymerization of dental cements.     

Reduction of carbamylated albumin by extended hemodialysis

Introduction Among conventional hemodialysis (CHD) patients, carbamylated serum albumin (C‐Alb) correlates with urea and amino acid deficiencies and is associated with mortality. We postulated that reduction of C‐Alb by intensive HD may correlate with improvements in protein metabolism and cardiac function. Methods One‐year observational study of in‐center nocturnal extended hemodialysis (EHD) patients and CHD control subjects. Thirty‐three patients receiving 4‐hour CHD who converted to 8‐hour EHD were enrolled, along with 20 controls on CHD. Serum C‐Alb, biochemistries, and cardiac MRI parameters were measured before and after 12 months of EHD. Findings EHD was associated with reduction of C‐Alb (average EHD change ?3.20 mmol/mol [95% CI ?4.23, ?2.17] compared to +0.21 [95% CI ?1.11, 1.54] change in CHD controls, P < 0.001). EHD was also associated with increases in average essential amino acids (in standardized units) compared to CHD (+0.38 [0.08, 0.68 95%CI]) vs. ?0.12 [?0.50, 0.27, 95% CI], P = 0.047). Subjects who reduced C‐Alb more than 25% were found to have reduced left ventricular mass, increased urea reduction ratio, and increased serum albumin compared to nonresponders, and % change in C‐Alb significantly correlated with % change in left ventricular mass. Discussion EHD was associated with reduction of C‐Alb as compared to CHD, and reduction of C‐Alb by EHD correlates with reduction of urea. Additional studies are needed to test whether reduction of C‐Alb by EHD also correlates with improved clinical outcomes.