Search results for "Scanning"
showing 10 items of 1808 documents
Nanosecond laser surface modification of AISI 304L stainless steel: Influence the beam overlap on pitting corrosion resistance
2014
Abstract Surface modifications of AISI 304L stainless steel by laser surface melting (LSM) were investigated using a nanosecond pulsed laser-fibre doped by ytterbium at different overlaps. The objective was to study the change in the corrosion properties induced by the treatment of the outer-surface of the stainless steel without modification of the bulk material. Different analytical techniques such as scanning electron microscopy (SEM), X-ray diffraction (XRD), and glow discharge optical emission spectrometry (GDOES) were used to characterize the laser-melted surface. The corrosion resistance was evaluated in a chloride solution at room temperature by electrochemical tests. The results sh…
Keggin heteropolyacid supported on TiO2 used in gas-solid (photo)catalytic propene hydration and in liquid-solid photocatalytic glycerol dehydration
2017
Abstract (Photo)catalytic propene hydration to 2-propanol and glycerol dehydration to acrolein were carried out by using Keggin heteropolyacids (HPAs) supported on TiO 2 . Binary materials have been prepared by impregnation of H 3 PW 12 O 40 , H 3 PMo 12 O 40 and H 4 SiW 12 O 40 , on TiO 2 Evonik P25. Moreover, a binary material consisting of H 4 SiW 12 O 40 and TiO 2 was prepared via a hydrothermal treatment and tested for the same reactions. All the materials were characterized by X-ray diffraction (XRD), scanning electron microscopy observations (SEM) coupled with energy dispersive X-ray (EDX) measurements, diffuse reflectance spectroscopy (DRS), Raman spectroscopy and Fourier transform …
Comparative study of the lubricant performance of Compritol® HD5 ATO and Compritol® 888 ATO: effect of polyethylene glycol behenate on lubricant capa…
2003
The aim of this paper is to study the lubricant capacity of Compritol HD5 ATO, a glyceryl and polyethylene glycol dibehenate, obtained by atomization. This material is compared to Compritol 888 ATO, constituted only by glyceryl dibehenate. First, this study verifies that Compritol HD5 ATO and Compritol 888 ATO present the same granular characteristics and that their mixes with Lactopress present no structural differences. Secondly, in term of compressibility and cohesiveness, the use of Compritol 888 ATO or Compritol HD5 ATO with Lactopress does not involve any significant modification. Finally, the minor difference of lubricant capacity between Compritol HD5 ATO and Compritol 888 ATO has n…
Microscale Marangoni actuation: All-optical and all-electrical methods
2006
We present experimental results from an all-optical microfluidic platform that may be complimented by a thin film all-electrical network. Using these configurations we have studied the microfluidic convective flow systems of silicone oil, glycerol, and 1,3,5-trinitrotoluene on open surfaces through the production of surface tension gradients derived from thermal gradients. We show that sufficient localized thermal variation can be created utilizing surface plasmons and/or engaging individually addressable resistive thermal elements. Both studies manipulate fluids via Marangoni forces, each having their unique exploitable advantages. Surface plasmon excitation in metal foils are the driving …
On the Relationship between Jetted Inks and Printed Biopatterns:Molecular-Thin Functional Microarrays of Glucose Oxidase
2009
Arrays of circular spots of glucose oxidase have been obtained on functionalized silicon oxide by piezoelectric inkjet printing and the enzymatic activity toward glucose recognition has been monitored. The addition of glycerol to the molecular ink allows to obtain high spot definition and resolution (tens of micrometers wide; one molecule tall), but in spite of its well-known structural stabilizing properties, in dynamic conditions it may lead to increased protein stresses. The jetting voltage and pulse length have been found to be critical factors for both activity retention and pattern definition. High voltages and pulse lengths results in stress effects along with the loss of activity, w…
A novel cytotoxin from Clostridium difficile serogroup F is a functional hybrid between two other large clostridial cytotoxins.
1999
Abstract The large clostridial cytotoxins (LCTs) constitute a group of high molecular weight clostridial cytotoxins that inactivate cellular small GTP-binding proteins. We demonstrate that a novel LCT (TcdB-1470) from Clostridium difficile strain 1470 is a functional hybrid between “reference” TcdB-10463 andClostridium sordellii TcsL-1522. It bound to the same specific receptor as TcdB-10463 but glucosylated the same GTP-binding proteins as TcsL-1522. All three toxins had equal enzymatic potencies but were equally cytotoxic only when microinjected. When applied extracellularly TcdB-1470 and TcdB-10463 were considerably more potent cytotoxins than TcsL-1522. The small GTP-binding protein R-R…
Solubility and microstructural development of TiO2-containing 3Al2O3·2SiO2 and 2Al2O3·SiO2 mullites obtained from single-phase gels
2007
Abstract The interdependence of the titanium oxide amount and the anisotropic growth of mullites prepared from single-phase gels were investigated. Gels with stoichiometries 3(Al2−xTixO3)·2(SiO2) and 2(Al2−xTixO3)·(SiO2), with 0 ≤ x ≤ 0.15 were prepared by the semialkoxide method. Gels and specimens heated at temperatures between 1200 and 1600 °C were characterized by using infrared spectroscopy (IR), X-ray diffraction (XRD) and transmission and field emission scanning electron microscopies (TEM and FESEM). Al2TiO5 as minor impurity was detected in both series of mullites for gel precursor compositions x = 0.10 and x = 0.15, obtained at temperatures between 1200 and 1600 °C. Variations of l…
Blood vessel segmentation and width estimation in ultra-wide field scanning laser ophthalmoscopy.
2014
Features of the retinal vasculature, such as vessel widths, are considered biomarkers for systemic disease. The aim of this work is to present a supervised approach to vessel segmentation in ultra-wide field of view scanning laser ophthalmoscope (UWFoV SLO) images and to evaluate its performance in terms of segmentation and vessel width estimation accuracy. The results of the proposed method are compared with ground truth measurements from human observers and with existing state-of-the-art techniques developed for fundus camera images that we optimized for UWFoV SLO images. Our algorithm is based on multi-scale matched filters, a neural network classifier and hysteresis thresholding. After …
Evolution of gynoecium morphology in Old World Papaveroideae: a combined phylogenetic/ontogenetic approach.
2011
PREMISE OF THE STUDY: The correct assessment of homology is an important prerequisite for reconstructing phylogenetic relationships and character evolution. Old World Papaveroideae (Papaver, Meconopsis, Roemeria, Stylomecon) show substantial diversity in gynoecium and capsule morphology. In particular, capsules can have distinct styles (Meconopsis p.p., Stylomecon) or a sessile stigmatic disc (Papaver). Molecular phylogenetic analyses of Old World Papaveroideae had shown that neither taxa with styles nor those with stigmatic discs represent monophyletic lineages. We here investigate whether either styles or stigmatic discs have arisen repeatedly during the diversification of Old World Papav…
The effects of anthropogenic particulate emissions on roadway dust and Nerium oleander leaves in Messina (Sicily, Italy)
2003
Complementary studies on the inorganic chemical composition of Nerium oleander leaves collected in the town of Messina (Sicily, Italy) and seven grain-size fractions of local roadway dust have been carried out. Data and maps are presented to show that the particulate matter present in the air of Messina contains trace elements significantly in excess with respect to the average continental earth crust. The anomalies follow the outline of the urban area, the highest concentrations of trace elements being observed where traffic density is highest. Chemical and isotopic analyses of both road dust and Nerium oleander leaves indicate that Pb contamination still characterizes roads with heavy tra…