Regression and Artificial Intelligence Models to Predict the Surface Roughness in Additive Manufacturing

In additive manufacturing (AM), it is necessary to study the surface roughness, which affected the building parameters such as layer thickness and building orientation. Some AM machines have minimum layer thickness that doesn't satisfy the desired roughness. Also, it produces a fine surface that isn't required. This increases the building time and cost without any benefits. To overcome these problems and achieve a certain surface roughness, a prediction model is proposed in this chapter. Regression models were used to predict the surface roughness through the building orientation. ANN was used to predict the surface roughness through the building orientation and the layer thickness together. ANN was constructed based on experimental work that study the effect of layer thickness and building orientation on the surface roughness. Some data were used in the training process and others were used in the verification process. The results show that the layer thickness parameter has an effect more than the building orientation parameter on the surface roughness.

Status of ESA’s independent Earth Orientation Parameter products

<p>The availability of highly accurate, up-to-date Earth Orientation Parameters is of major importance for all positioning and navigation applications on Earth, Sea, Air and also in Space. This is equally true for ESA missions and the EU space programs, e.g. Galileo, EGNOS and Copernicus.</p><p>In the frame of its responsibility to provide the Geodetic reference for ESA missions, ESA’s Navigation Support Office at ESOC is already contributing to the realisation of the International Terrestrial Reference Frame (ITRF) and the combined Earth Orientation Parameters provided by the International Earth Rotation Service (IERS). The contribution is realised through individual contributions to international services such as the International GNSS Service (IGS), the International Laser Ranging Services (ILRS), the International DORIS Service (IDS), the International Earth Rotation Service (IERS) and in the future also to the International VLBI Service (IVS).</p><p>For the combination and the long-term predictions of the Earth orientation products ESA is still relying on the International Earth Rotation Service (IERS). Over the past years, ESA repeatedly experienced problems with outdated or missing predictions of the Earth orientation parameters (Bulletin A). Considering the importance of up-to-date Earth orientation parameters, the dependence on a single source outside Europe is considered a risk for European industry, for ESA missions and for EU programmes. For this reason, ESA initiated in 2017 a study with the target to develop independent ESA Earth Orientation parameter products. This study, executed by a consortium led by the Deutsches Geodätisches Forschungsinstitut (DGFI-TUM), is expected to finish in the course of this year.</p><p>In this presentation we will give an overview of ESAs up-to-date reference products and discuss their quality. It will outline the combination approach and discuss the way forward to an fully operational provision of the ESA Earth Orientation Parameter products.</p>

SELECTION EFFECTS AND STRUCTURAL SYMMETRIES IN THE ORIENTATION BASED UNIFIED SCHEME

Using the projected linear size, (D) as an orientation parameter, the armlength ratio, (Q) and the lobe-luminosity ratio, (R) as asymmetry parameters, we test the FR-II galaxies (Gs) and radio-loud quasar (Qs) unification scheme. Using the median values of our binned sample, our results, generally indicate that the D of the radio sources are smaller at higher redshifts z and at larger Q values, with the D of Qs smaller than those of Gs across all Q, z and R bins. Also, the D of Gs appear smaller for lower values of Q, if R ≤ 1.0 but become larger at higher values of Q if R > 1.0. For Qs, the D decreases with increasing Q, R and z. These results imply that the beaming effect is more important in Qs than in Gs. The D − R regression analyses for different Q and z subsamples suggest the importance of factors other than beaming and orientation in the interpretation of the evolution of these radio sources.

Effect of Shear Rate on the Orientation and Relaxation of a Vanillic Acid Based Liquid Crystalline Polymer

In this study, we report on the visco-elastic response during start-up and cessation of shear of a novel bio-based liquid crystal polymer. The ensuing morphological changes are analyzed at different length scales by in-situ polarized optical microscopy and wide-angle X-ray diffraction. Upon inception of shear, the polydomain texture is initially stretched, at larger strain break up processes become increasingly important, and eventually a steady state texture is obtained. The shear stress response showed good coherence between optical and rheo-X-ray data. The evolution of the orientation parameter coincides with the evolution of the texture: the order parameter increases as the texture stretches, drops slightly in the break up regime, and reaches a constant value in the plateau regime. The relaxation of the shear stress and the polydomain texture showed two distinct processes with different timescales: The first is fast contraction of the stretched domain texture; the second is the slow coalescence of the polydomain texture. The timescale of the orientation parameter’s relaxation matched with that of the slow coalescence process. All processes were found to scale with shear rate in the tested regime. These observations can have far reaching implications for the processing of liquid crystal polymers as they indicate that increased shear rates during processing can correspond to an increased relaxation rate of the orientation parameter and, therefore, a decrease in anisotropy and material properties after cooling.

CALIBRATION OF A MULTI-CAMERA ROVER

Multi-Camera-Rover are recently coming up for usual terrestrical surveying tasks. This technique is new for the surveyors. Although photogrammetric specialists realize the benefits of such systems immediately, surveyors have difficulties to find efficient usages. To approach this new measurement systems the technique has to be understood and the confidence on the accuray has to grow. In this paper we analyze the accuracy of a Multi-Camera-Rover using an indoor testfield by photogrammetric algorithms. The results show that the knowledge of the interior orientation parameter of the cameras and the relative orientation of the cameras is essential for precise geometric reconstructions. Knowing these additional data, high accurate results become possible.

CALIBRATION OF A MULTI-CAMERA ROVER

Multi-Camera-Rover are recently coming up for usual terrestrical surveying tasks. This technique is new for the surveyors. Although photogrammetric specialists realize the benefits of such systems immediately, surveyors have difficulties to find efficient usages. To approach this new measurement systems the technique has to be understood and the confidence on the accuray has to grow. In this paper we analyze the accuracy of a Multi-Camera-Rover using an indoor testfield by photogrammetric algorithms. The results show that the knowledge of the interior orientation parameter of the cameras and the relative orientation of the cameras is essential for precise geometric reconstructions. Knowing these additional data, high accurate results become possible.