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Processing Parameters for Selective Laser Melting (SLM) of Gold
Research into laser processing of different metals has enabled Solid Freeform Fabrication (SFF)
processes to produce parts for a wide variety of applications. However, less focus has been made
on the processing of precious metals. Currently little research has been reported on the
processing of precious metals and alloys using the Selective Laser Melting (SLM) process. Here
we present an initial investigation into the processing of 24 carat gold (Au) powder using a SLM
system. Gold powder was tested for apparent density, tap density, particle shape and size
distribution. A quality check of the specimen was carried out using a Scanning Electron
Microscope (SEM) for sinterability and occurrence of porosity. Significant processing
parameters were also identified.Mechanical Engineerin
Effectiveness of Geo-Energy Usage during Underground Mining of Deposits
Topicality of rock pressure energy usage in technologies of underground mining of
deposits is revealed. Methodology of geo-energy processes research in the interior of the Earth is
described. Energy theory of zonal capsulation parameters research by massif of underground
workings is proposed. Results verification of theoretical research is executed by laboratory and
industrial tests conducting. Economic and mathematical model of determination of unit costs on
types of mining operations is substantiated and volumes of savings during usage of geo-energy
during mining operations conducting are determine
Resonant X-ray diffraction studies on the charge ordering in magnetite
Here we show that the low temperature phase of magnetite is associated with
an effective, although fractional, ordering of the charge. Evidence and a
quantitative evaluation of the atomic charges are achieved by using resonant
x-ray diffraction (RXD) experiments whose results are further analyzed with the
help of ab initio calculations of the scattering factors involved. By
confirming the results obtained from X-ray crystallography we have shown that
RXD is able to probe quantitatively the electronic structure in very complex
oxides, whose importance covers a wide domain of applications.Comment: 4 pages 4 figures, accepted for publication in PR
From Multiview Image Curves to 3D Drawings
Reconstructing 3D scenes from multiple views has made impressive strides in
recent years, chiefly by correlating isolated feature points, intensity
patterns, or curvilinear structures. In the general setting - without
controlled acquisition, abundant texture, curves and surfaces following
specific models or limiting scene complexity - most methods produce unorganized
point clouds, meshes, or voxel representations, with some exceptions producing
unorganized clouds of 3D curve fragments. Ideally, many applications require
structured representations of curves, surfaces and their spatial relationships.
This paper presents a step in this direction by formulating an approach that
combines 2D image curves into a collection of 3D curves, with topological
connectivity between them represented as a 3D graph. This results in a 3D
drawing, which is complementary to surface representations in the same sense as
a 3D scaffold complements a tent taut over it. We evaluate our results against
truth on synthetic and real datasets.Comment: Expanded ECCV 2016 version with tweaked figures and including an
overview of the supplementary material available at
multiview-3d-drawing.sourceforge.ne
Linking Visual Cortical Development to Visual Perception
Defense Advanced Research Projects Agency and the Office of Naval Research (N00014-95-1-0409); National Science Foundation (IRI-97-20333); Office of Naval Research (N00014-95-1-0657
Radiotherapy planning for glioblastoma based on a tumor growth model: Improving target volume delineation
Glioblastoma are known to infiltrate the brain parenchyma instead of forming
a solid tumor mass with a defined boundary. Only the part of the tumor with
high tumor cell density can be localized through imaging directly. In contrast,
brain tissue infiltrated by tumor cells at low density appears normal on
current imaging modalities. In clinical practice, a uniform margin is applied
to account for microscopic spread of disease.
The current treatment planning procedure can potentially be improved by
accounting for the anisotropy of tumor growth: Anatomical barriers such as the
falx cerebri represent boundaries for migrating tumor cells. In addition, tumor
cells primarily spread in white matter and infiltrate gray matter at lower
rate. We investigate the use of a phenomenological tumor growth model for
treatment planning. The model is based on the Fisher-Kolmogorov equation, which
formalizes these growth characteristics and estimates the spatial distribution
of tumor cells in normal appearing regions of the brain. The target volume for
radiotherapy planning can be defined as an isoline of the simulated tumor cell
density.
A retrospective study involving 10 glioblastoma patients has been performed.
To illustrate the main findings of the study, a detailed case study is
presented for a glioblastoma located close to the falx. In this situation, the
falx represents a boundary for migrating tumor cells, whereas the corpus
callosum provides a route for the tumor to spread to the contralateral
hemisphere. We further discuss the sensitivity of the model with respect to the
input parameters. Correct segmentation of the brain appears to be the most
crucial model input.
We conclude that the tumor growth model provides a method to account for
anisotropic growth patterns of glioblastoma, and may therefore provide a tool
to make target delineation more objective and automated
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