Improvement of Machining Thin-Walled Parts Generated by Hybrid Manufacturing Using Optimalized Support

This paper is intended to show the problem in the production of thin-walled parts using hybrid manufacturing. It is necessary to machine the parts generated by 3D printing at certain stages of the production process. The problem can occur when machining thin-walled parts. This paper shows a way of change the critical depth of cut by adding a supporting structure instead of changingthe cutting parameters

Continuum regime motion of a growing droplet in opposing thermo-diffusiophoretic and gravitational fields of a thermal diffusion cloud chamber

A model for the motion of aerosol particles by Stefan flow, thermo-diffusiophoresis and gravity in a continuum regime is described, which considers a phase change on the particle surface. It is tested in a thermal diffusion cloud chamber where a droplet formed by nucleation quickly grows and simultaneously moves upwards due to vertical temperature and concentration gradients. Kinetic coefficients are assumed to be constant. Model predictions of the height where the droplet reverses its motion are in satisfactory agreement with the experimental results of Ždímal et al. ((1996). Colloids Surfaces A, 106, 119). The droplet motion seems to be predicted well at higher gradients and vapor fluxes, but model underestimates droplet motion at lower ones. For those cases also the free-molecule and transition regimes need to be included. Copyright © 2001 Elsevier Science B.V

Size resolved mass concentration and elemental composition of atmospheric aerosols over the Eastern Mediterranean area

International audienceA Berner low pressure impactor was used to collect size-segregated aerosol samples at Finokalia, located on the north-eastern coast of Crete, Greece during July 2000 and January 2001. Several samples were also collected during the summer campaign aboard the research vessel "AEGAIEO" in the Aegean Sea. Gravimetric analysis and inversion techniques yielded daily PM1 and PM10 mass concentrations. The samples were also analysed by PIXE giving the elemental size distributions of Al, Si, K, Ca, Ti, Mn, Fe, Sr, S, Cl, Ni, V, Cu, Cr, Zn, and Pb. The crustal elements and sea-salt had a unimodal supermicron size distribution. Sulphur was found predominantly in submicron fractions. K, V, and Ni exhibited a bimodal distribution with a submicron mode produced by forest fires and oil combustion. The anthropogenic elements had broad and not well-defined distributions. The time series for PM1 and PM10 mass and elemental concentrations showed both daily and seasonal variation. Higher mass concentrations were observed during two incursions of Saharan dust, whilst higher concentrations of S, Cu, Zn, and Pb were encountered in samples collected in air masses arriving from northern Greece or the western coast of Turkey. Elevated concentrations of chlorine were found in samples with air masses either originating above the Atlantic Ocean and arriving at Finokalia via western Europe or recirculating over the western coast of the Black Sea

Influence of static unbalance on rotors with various journal bearing types

This paper was supported by the Technology Agency of the Czech Republic under the THETA Programme within the TK04020057 project

Local phenomena in tilting-pad journal bearing’s pivot

the THETA Programme within the TK04020057 project

Analysis of autoparametric double pendulum

This research work was supported by the Czech Science Foundation project 23-07280S entitled ”Identification and compensation of imperfections and friction effects in joints of mechatronic systems”

Mesoscale modeling of combined aerosol and photo-oxidant processes in the Eastern Mediterranean

International audienceParticulate matter and photo-oxidant processes in the Eastern Mediterranean have been studied using the UAM-AERO mesoscale air quality model in conjunction with the NILU-CTM regional model. Meteorological data were obtained from the RAMS prognostic meteorological model. The modeling domain includes the eastern Mediterranean area between the Greek mainland and the island of Crete. The modeling system is applied to study the atmospheric processes in three periods, i.e. 13?16 July 2000, 26?30 July 2000 and 7?14 January 2001. The spatial and temporal distributions of both gaseous and particulate matter pollutants have been extensively studied together with the identification of major emission sources in the area. The modeling results were compared with field data obtained in the same period. The objective of the current modeling work was mainly to apply the UAM-AERO mesoscale model in the eastern Mediterranean in order to assess the performed field campaigns and determine that the applied mesoscale model is fit for this purpose. Comparison of the modeling results with measured data was performed for a number of gaseous and aerosol species. The UAM-AERO model underestimates the PM10 measured concentrations during summer and winter campaigns. Discrepancies between modeled and measured data are attributed to unresolved particulate matter emissions. Particulate matter in the area is mainly composed by sulphate, sea salt and crustal materials, and with significant amounts of nitrate, ammonium and organics. During winter the particulate matter and oxidant concentrations were lower than the summer values

Vibration analysis of a vertical rotor immersed in fluid at extreme operating temperatures

This publication was supported by the project 22-29874S of the Czech Science Foundation. The usage of the AVL Excite software in the framework of the University Partnership Program of AVL List GmbH is greatly acknowledge

Indoor aerosol particle deposition in an empty office

The size- and time-resolved indoor/outdoor aerosol concentration relationships were studied experimentally in an empty office without internal particle sources. Two Scanning Mobility Particle Sizers (SMPS) and an Aerodynamic Particle Sizer (APS) sampled alternately from indoor and outdoor, together covering the size range 3-10,000 nm. The results showed that the indoor aerosol concentration depends mainly on the air exchange and deposition rates, and the outdoor concentration. At higher air exchange rates the indoor aerosol concentration approaches the outdoor one. This was observed for the accumulation mode particles. The size-dependent deposition rates were estimated using a simple aerosol dynamics experiment. It was based on equilibration of the indoor/outdoor concentrations by opening windows and analyzing the concentration decay curves after the windows were closed. For this purpose a simple mass balance model was used. The overall loss rate and the asymptotic value of indoor concentration were found by applying a non-linear least squares method on the time dependence of the indoor concentrations. The air exchange rate was estimated from the overall loss rate and the steady state values of the indoor/outdoor concentration of the accumulation mode particles. © Springer 2005

Treatise on dynamic behaviour modelling of tilting pad journal bearing under operating conditions: From the real world to numerical simulations

the THETA Programme within the TK04020057 projec