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Understanding the nanoscale electrostatic interaction between a conductive atomic force microscopy (AFM) probe and a dielectric film is central to the operation of various nanoscale dielectric microscopies and determination of dielectric properties of the film. There is no simple analytical description of the electrostatic interaction generated in the confined probe-sample geometry for neither static nor dynamic AFM modes used in dielectric measurements. An accurate description of the involved physics is obtained only by means of a finite element analysis modeling of the system. However, the alternative to using the numerical analysis is not very popular due to being slower and requiring relatively high computation resources. In this work, we revised the contributions from different parts of the AFM probe to the probe-sample capacitance by both analytical and numerical methods. We tried to reconciliate the two approaches and observed the differences as a function of geometry and material parameters. Under various noise levels, the efficiency of an analytical model was tested against a finite element analysis that captures in detail the electrostatic interaction in AFM-based dielectric measurements. The investigation was performed in both spectroscopic force-distance curves and constant height scans with measurements for deflection and frequency of the AFM probe. The obtained measurement sensitivities are relevant in selecting the optimal scanning mode and its operational parameters for a given film thicknesses and dielectric constants but also show the critical role of the numerical analysis to the correct interpretation of the measurements. [ABSTRACT FROM AUTHOR]

The accuracy of a CNC machine tool is one of the most important parameters that make the geometry and dimensions of the work pieces comply with the tolerance limits specified through the designer's technical drawing. When a machine tool is handed over to the customer it is compliant in terms of the accuracy limits specified in the documentation but, after a time interval of usage, because of the wear of the components in relative motion and machine exploitation conditions. This work suggests an innovating method of testing the accuracy of a CNC machine tool by using the "calliper", with a view to enhancing the positioning accuracy of the feed kinematic linkages. After designing and manufacturing this device, the measurement of the target points on the coordinate measuring machine is necessary, so that this device becomes a "calliper". For inspecting the machine tool, the "calliper" is located on the machine table, being measured at the target points by means of the probe with the tactile shooter that belongs to the machine. The measurement results are stored and compared to the results of the measurements performed through the coordinate measuring machine. In function of the two measurements the related corrections of the errors will be done in the software of machine tool numerical control. [ABSTRACT FROM AUTHOR]

CNC Gantry Type Machine Tools with great distance between slides (gantry milling machines, plasma and laser gantry cutting machines, vertical lathe machines, etc) are used extensively in the manufacturing of large and long components. Because this type of Machine Tool it is used to machine large parts at high speeds, significant heat will be produce at the cutting tool level and transmitted thru the tool holder to the ram or spindled and then to the ream case guideways. Heat it's also generated when using a ball screw actuation for the main axis because of the friction forces at the ball screw level. Due to material expansion, the heat generated during the machining process can influence the precision of the Machine Tool. In this paper, finite element analysis (FEA) was used to analyze the influence of the temperature on the rigidity of the Machine Tool guideways. The results of the studies performed will provide the machine tool builder with important information regarding the points that need to be address in order to help in improving thermal compensation. [ABSTRACT FROM AUTHOR]

A fundamental study of two turbulent, directly opposed impinging jets in a stagnant ambient fluid, unconfined or uninfluenced by far-field walls, is presented. By experimental investigation and numerical modeling the fundamental characteristics of direct impingement of two turbulent axisymmetric round jets under seven different geometrical and flow-rate configurations (L* = Lid = {5, 10, 20}, where L is nozzle to nozzle separation distance and d is nozzle diameter, and Re = [Rho][U.sub.0]d/[Mu] = {1500, 4500, 7500, 11000}, where [Rho] is fluid density, [Mu] is dynamic viscosity of fluid, and [U.sub.0] is average initial velocity of fluid) are discussed. Flow visualization and velocity measurements performed using various laser-based techniques have revealed the effects of Reynolds number Re and dimensionless nozzle to nozzle separation L* on the complex flow structure. Similarity analysis of the initial freejet development and developing radial jet found Re = 11 X [10.sup.3] and L* = 20 as the only case where the freejets exhibit a self-preserving development. However, the jets show significant growth with axial and radial distance for Re = 7.5 x [10.sup.3] and L* = 20. All other experimental cases show little or no axial growth as a result of shorter development length. When used to simulate the present flow, the standard k-[Epsilon] turbulence model showed little disagreement between computed and experimental mean velocities and poor predictions as far as the jet growth rates are concerned.