Search results for "Additive"
showing 10 items of 297 documents
Electropolishing of CuZn brasses and 316L stainless steels: Influence of alloy composition or preparation process (ALM vs. standard method)
2016
International audience; In the present paper, electropolishing behavior of different brass alloys (CuZn39Pb2, CuZn42) in phosphoric acid is studied to observe the impact of alloying elements on polishing quality. In the same way, the influence of the manufacturing process is also evaluated through the comparison of a “standard” stainless steel and a stainless steel prepared by Additive Laser Manufacturing (ALM). An electrochemical study was first performed to determine the best treatment conditions for each material/electrolyte pair and to study the electropolishing mechanism and its kinetic dependence on diffusion. Metallic samples are fully characterized before and after electropolishing …
Ultrasonic phased array inspection of wire plus arc additive manufacture samples using conventional and total focusing method imaging approaches
2019
In this study, three aluminium samples produced by wire + arc additive manufacture (WAAM) are inspected using ultrasonic phased array technology. Artificial defects are machined using a centre drill, ø 3 mm, and electrical discharge machining (EDM), ø 0.5-1 mm, in a cylindrical through-hole topology. The samples are first inspected using a single-element wheel probe mounted on a KUKA robot in order to investigate the feasibility of using a conventional ultrasonic transducer approach. Unfortunately, the wheel probe is found to be unsuitable for scanning the WAAM specimens and ultrasonic phased arrays are employed next. The set-up includes 5 MHz and 10 MHz arrays (128 elements) in direct cont…
Influence of thermal process on structure and functional properties of emulsion-based edible films
2007
Abstract Synthetic food packaging is classically used to prevent mass transfer of various small molecules (water, gases, flavour compounds or solutes) between a food and its surrounding medium. In the case of composite foods, the development of edible films and coatings, applied between the different phases of this food is rising up. The increase of such food products shelf-life is indeed related to the barrier efficiency of these edible packaging against small molecules transfers. This is especially true for water transfer between compartments of different water activities in the same food, that leads to important physico-chemical changes and therefore to food quality deterioration. Film-f…
Stochastic analysis of external and parametric dynamical systems under sub-Gaussian Levy white-noise
2008
In this study stochastic analysis of non-linear dynamical systems under α-stable, multiplicative white noise has been conducted. The analysis has dealt with a special class of α-stable stochastic processes namely sub-Gaussian white noises. In this setting the governing equation either of the probability density function or of the characteristic function of the dynamical response may be obtained considering the dynamical system forced by a Gaussian white noise with an uncertain factor with α/2- stable distribution. This consideration yields the probability density function or the characteristic function of the response by means of a simple integral involving the probability density function …
Two-level Schwarz method for unilateral variational inequalities
1999
The numerical solution of variational inequalities of obstacle type associated with second-order elliptic operators is considered. Iterative methods based on the domain decomposition approach are proposed for discrete obstacle problems arising from the continuous, piecewise linear finite element approximation of the differential problem. A new variant of the Schwarz methodology, called the two-level Schwarz method, is developed offering the possibility of making use of fast linear solvers (e.g., linear multigrid and fictitious domain methods) for the genuinely nonlinear obstacle problems. Namely, by using particular monotonicity results, the computational domain can be partitioned into (mes…
Subsignal-based denoising from piecewise linear or constant signal
2011
15 pages; International audience; n the present work, a novel signal denoising technique for piecewise constant or linear signals is presented termed as "signal split." The proposed method separates the sharp edges or transitions from the noise elements by splitting the signal into different parts. Unlike many noise removal techniques, the method works only in the nonorthogonal domain. The new method utilizes Stein unbiased risk estimate (SURE) to split the signal, Lipschitz exponents to identify noise elements, and a polynomial fitting approach for the sub signal reconstruction. At the final stage, merging of all parts yield in the fully denoised signal at a very low computational cost. St…
Additive properties of fractal sets on the parabola
2023
Let $0 \leq s \leq 1$, and let $\mathbb{P} := \{(t,t^{2}) \in \mathbb{R}^{2} : t \in [-1,1]\}$. If $K \subset \mathbb{P}$ is a closed set with $\dim_{\mathrm{H}} K = s$, it is not hard to see that $\dim_{\mathrm{H}} (K + K) \geq 2s$. The main corollary of the paper states that if $0 0$. This information is deduced from an $L^{6}$ bound for the Fourier transforms of Frostman measures on $\mathbb{P}$. If $0 0$, then there exists $\epsilon = \epsilon(s) > 0$ such that $$ \|\hat{\mu}\|_{L^{6}(B(R))}^{6} \leq R^{2 - (2s + \epsilon)} $$ for all sufficiently large $R \geq 1$. The proof is based on a reduction to a $\delta$-discretised point-circle incidence problem, and eventually to the $(s,2s)$-…
Equivalence Relations on Stonian Spaces
1996
Abstract Quotient spaces of locally compact Stonian spaces which generalize in some sense the concept of Stone representation space of a Boolean algebra are investigated emphasizing the measure theoretical point of view, and a representation theorem for finitely additive measures is proved.
A holistic approach to design for 4D Printing
2019
Invented in 1983, as a rapid prototyping process, additive manufacturing (AM) is nowadays considered as a manufacturing process almost in the same way as conventional processes. For example, parts obtained by AM are found in aircraft structures. This AM evolution is mainly due to the shape complexity allowed by the process. The driving forces behind this evolution include: the development of various techniques on the layer-wise manufacturing principle and the improvement both in quantity and quality of the range of materials that can be processed. Many other AM techniques and materials continue to emerge. In the wake of the AM (usually referred to as 3D printing) another mode of manufacturi…
Polysaccharide remains in Maya mural paintings: is it an evidence of the use of plant gums as binding medium of pigments and additive in the mortar?
2020
A number of monosaccharides characteristic of plant gums were found in paint layers and preparation layers of samples of Maya mural paintings of 10 archaeological sites located in Campeche and Yucatan regions. This finding opens the question about the deliberate use of these organic polymers as additives for improving workability and mechanical properties in the preparation layer mortar and conferring cohesion to the pigments in the paint layer. The study performed by GC-MS has confirmed the presence, in significant amounts, of a series of monosaccharides, being glucose and mannose between the most abundantly found. Nevertheless, the low amount present in most of the samples hindered the qu…