STRESS STATE STUDY FOR PARTS OF ALUMINIUM-MAGNESIUM AND ALUMINIUM WROUGHT ALLOYS AT ROTARY SPINNING

The paper deals with the problems of rotary spinning of pipe or sheet workpieces made of aluminium-magnesium and aluminium wrought alloys. The need to control depth distribution of internal stresses in the workpiece surface layer in the rotary spinning process is determined. An Al-Mg5 aluminum alloy part is researched, which is obtained after 3 - stage rotary spinning. By the use of non-destructive resistance electric contact method, measurements and analysis of the stressed state for the workpieces after each stage of rotary spinning are made. According to the experiment planning theory, research of the influence of processing and thermal treatment modes on the levels of residual stresses σ in the workpieces material is conducted. The value of the residual stresses is assumed as an optimization parameter, and the technological modes of spinning and the modes of the thermal treatment applied between the rotary spinning stages - as factors of the process. Statistical estimation is made, which makes it possible to obtain an adequate mathematical model (estimated by the Fisher’s criterion) describing the relation between the optimization parameter and the optimization factors. Technological processing modes with the lowest level of residual stresses in the surface layer of the researched samples and the optimal depth distribution of residual stresses in the workpiece surface layer are obtained. Developed method is applicable in all operating conditions for parts manufacturing of different geometry and different materials

Ozone mixing ratios inside tropical deep convective clouds from OMI satellite measurements

We have developed a new technique for estimating ozone mixing ratio inside deep convective clouds. The technique uses the concept of an optical centroid cloud pressure that is indicative of the photon path inside clouds. Radiative transfer calculations based on realistic cloud vertical structure as provided by CloudSat radar data show that because deep convective clouds are optically thin near the top, photons can penetrate significantly inside the cloud. This photon penetration coupled with in-cloud scattering produces optical centroid pressures that are hundreds of hPa inside the cloud. We combine measured column ozone and the optical centroid cloud pressure derived using the effects of rotational-Raman scattering to estimate O<sub>3</sub> mixing ratio in the upper regions of deep convective clouds. The data are obtained from the Ozone Monitoring Instrument (OMI) onboard NASA's Aura satellite. Our results show that low O<sub>3</sub> concentrations in these clouds are a common occurrence throughout much of the tropical Pacific. Ozonesonde measurements in the tropics following convective activity also show very low concentrations of O<sub>3</sub> in the upper troposphere. These low amounts are attributed to vertical injection of ozone poor oceanic boundary layer air during convection into the upper troposphere followed by convective outflow. Over South America and Africa, O<sub>3</sub> mixing ratios inside deep convective clouds often exceed 50 ppbv which are comparable to mean background (cloud-free) amounts and are consistent with higher concentrations of injected boundary layer/lower tropospheric O<sub>3</sub> relative to the remote Pacific. The Atlantic region in general also consists of higher amounts of O<sub>3</sub> precursors due to both biomass burning and lightning. Assuming that O<sub>3</sub> is well mixed (i.e., constant mixing ratio with height) up to the tropopause, we can estimate the stratospheric column O<sub>3</sub> over clouds. Stratospheric column ozone derived in this manner agrees well with that retrieved independently with the Aura Microwave Limb Sounder (MLS) instrument and thus provides a consistency check of our method

Cloud products from the Earth Polychromatic Imaging Camera (EPIC): algorithms and initial evaluation

This paper presents the physical basis of the Earth Polychromatic Imaging Camera (EPIC) cloud product algorithms and an initial evaluation of their performance. Since June 2015, EPIC has been providing observations of the sunlit side of the Earth with its 10 spectral channels ranging from the UV to the near-infrared. A suite of algorithms has been developed to generate the standard EPIC Level 2 cloud products that include cloud mask, cloud effective pressure/height, and cloud optical thickness. The EPIC cloud mask adopts the threshold method and utilizes multichannel observations and ratios as tests. Cloud effective pressure/height is derived with observations from the O2 A-band (780 and 764&thinsp;nm) and B-band (680 and 688&thinsp;nm) pairs. The EPIC cloud optical thickness retrieval adopts a single-channel approach in which the 780 and 680&thinsp;nm channels are used for retrievals over ocean and over land, respectively. Comparison with co-located cloud retrievals from geosynchronous earth orbit (GEO) and low earth orbit (LEO) satellites shows that the EPIC cloud product algorithms are performing well and are consistent with theoretical expectations. These products are publicly available at the Atmospheric Science Data Center at the NASA Langley Research Center for climate studies and for generating other geophysical products that require cloud properties as input.</p

An integrated approach to development and simulation manufacturing processes of optical products

The engineering management process and automation method for making pilot set of optical polymer parts used in LED systems are considered. Optical system and lens geometry development are realized in Zemax. 3D model and molding tools with further generating of NC coded data are developed in Cimatron E. Pre simulation of injection molding process is realized in Moldex3D and thermo-mechanical analysis is provided by OOFELIE. 3D printer Objet is used for parts prototyping on different stages of the process. Data and process management are realized with a help of PDM system SmarTeam

FUNCTIONAL SURFACE MICROGEOMETRY PROVIDING THE DESIRED PERFORMANCE OF AN AIRCRAFT VIBRATION SENSOR

Subject of Research. The paper deals with the methods of efficiency improving for piezoelectric vibration sensors used in aircraft industry to control the level of vibration of gas turbine engines. The study looks into the matter of surface microgeometry effect of the vibro sensor part on its transverse sensitivity ratio. Measures are proposed to improve the sensor performance without cost supplement by optimization of the functional surface microgeometry. Method. A method for determination of the best possible surface microgeometry within the specific production conditions is shown. Also, a method for microgeometry estimation of the functional surfaces using graphical criteria is used. Taguchi method is used for design of experiment for functional surfaces machining. The use of this method reduces significantly the number of experiments without validity loss. Main Results. The relationship between technological factors of manufacturing the vibration sensor parts and its sensitivity has been found out. The optimal surface machining methods and process conditions for parts ensuring the best possible sensitivity have been determined. Practical Relevance. Research results can be used by instrument-making companies to improve the process of piezoelectric vibration sensor design and manufacturing

Accounting for the effects of surface BRDF on satellite cloud and trace-gas retrievals: a new approach based on geometry-dependent Lambertian equivalent reflectivity applied to OMI algorithms

Most satellite nadir ultraviolet and visible cloud, aerosol, and trace-gas algorithms make use of climatological surface reflectivity databases. For example, cloud and NO₂ retrievals for the Ozone Monitoring Instrument (OMI) use monthly gridded surface reflectivity climatologies that do not depend upon the observation geometry. In reality, reflection of incoming direct and diffuse solar light from land or ocean surfaces is sensitive to the sun–sensor geometry. This dependence is described by the bidirectional reflectance distribution function (BRDF). To account for the BRDF, we propose to use a new concept of geometry-dependent Lambertian equivalent reflectivity (LER). Implementation within the existing OMI cloud and NO₂ retrieval infrastructure requires changes only to the input surface reflectivity database. The geometry-dependent LER is calculated using a vector radiative transfer model with high spatial resolution BRDF information from the Moderate Resolution Imaging Spectroradiometer (MODIS) over land and the Cox–Munk slope distribution over ocean with a contribution from water-leaving radiance. We compare the geometry-dependent and climatological LERs for two wavelengths, 354 and 466 nm, that are used in OMI cloud algorithms to derive cloud fractions. A detailed comparison of the cloud fractions and pressures derived with climatological and geometry-dependent LERs is carried out. Geometry-dependent LER and corresponding retrieved cloud products are then used as inputs to our OMI NO₂ algorithm. We find that replacing the climatological OMI-based LERs with geometry-dependent LERs can increase NO₂ vertical columns by up to 50 % in highly polluted areas; the differences include both BRDF effects and biases between the MODIS and OMI-based surface reflectance data sets. Only minor changes to NO₂ columns (within 5 %) are found over unpolluted and overcast areas