Search results for "Design of experiments"
showing 10 items of 41 documents
On the Heuristic Procedure to Determine Processing Parameters in Additive Manufacturing Based on Materials Extrusion
2020
We present a heuristic procedure for determining key processing parameters (PPs) in materials-extrusion-based additive manufacturing processes. The concept relies on a design-of-experiment approach and consists of eleven &ldquo
The use of exploratory experimental designs combined with thermal numerical modelling to obtain a predictive tool for hybrid laser/MIG welding and co…
2011
Abstract While hybrid laser welding and coating processes involve a large number of physical phenomena, it is currently impossible to predict, for a given set of influencing factors, the shape of the molten zone and the history of temperature fields inside the parts. This remains true for complex processes, such as the hybrid laser/MIG welding process, which consists in combining a laser beam with a MIG torch. The gains obtained result essentially from the synergy of the associated processes: the stability of the process, the quality of the seam realized, and the productivity are increased. This article shows how, by means of a reduced number of experiments (8), it is possible to predict th…
Reducing sample size in experiments with animals: historical controls and related strategies
2015
Reducing the number of animal subjects used in biomedical experiments is desirable for ethical and practical reasons. Previous reviews of the benefits of reducing sample sizes have focused on improving experimental designs and methods of statistical analysis, but reducing the size of control groups has been considered rarely. We discuss how the number of current control animals can be reduced, without loss of statistical power, by incorporating information from historical controls, i.e. subjects used as controls in similar previous experiments. Using example data from published reports, we describe how to incorporate information from historical controls under a range of assumptions that mig…
Development of a new indole derivative dry powder for inhalation for the treatment of biofilm-associated lung infections
2022
The aim of this work was to produce an inhalable dry powder formulation of a new anti-biofilm compound (SC38). For this purpose, chitosan was used as a polymeric carrier and l-leucine as a dispersibility enhancer. SC38 was entrapped by spray-drying into previously optimized chitosan microparticles. The final formulation was fully characterized in vitro in terms of particle morphology, particle size and distribution, flowability, aerodynamic properties, anti-biofilm activity and effects on lung cell viability. The SC38-loaded chitosan microparticles exhibited favorable aerodynamic properties with emitted and respirable fractions higher than 80 % and 45 % respectively. The optimized formulati…
Design optimization of mooring system: An application to a vessel-shaped offshore fish farm
2019
Abstract Design optimization of mooring systems of offshore floating structures is a challenging task, partly because of the large number of design variables, complicated design constraints, nonlinear system behavior, and time-consuming numerical simulations. For engineering designs, efficient yet accurate approaches are needed. This paper proposes an integrated optimization methodology for design of mooring systems. The methodology integrates the design of experiments, screening analysis, time-domain simulations, and a metamodel-based optimization procedure. To demonstrate the methodology, the mooring system of a vessel-shaped offshore fish farm was designed considering the ultimate limit …
Supply chain modelling and analysis: an application of Latin square to a repeated coupling of non-linear differential equations
2011
In the last 50 years, Forrester’s system dynamics techniques have been adopted to analyse problems and find solutions for global supply chains. An important topic in production-inventory system modelling is the design of experiment. The aim of this paper is to present an application of a statistical technique of design of experiment, the Latin Square Design, to set a combination of input values for the initial-value problem of non-linear repeated coupling of first-order differential equations modelling a production-inventory system. This design permits to reduce the number of experiments while allowing statistical analysis for testing the significance of the studied parameters.
Fast-multivariate optimization of chiral separations in capillary electrophoresis: Anticipative strategies
2014
Abstract The design of experiments (DOE) is a good option for rationally limiting the number of experiments required to achieve the enantioresolution (Rs) of a chiral compound in capillary electrophoresis. In some cases, the modeled Rs after DOE analysis can be unsatisfactory, maybe because the range of the explored factors (DOE domain) was not the adequate. In these cases, anticipative strategies can be an alternative to the repetition of the process (e.g. a new DOE), to save time and money. In this work, multiple linear regression (MLR)-steepest ascent and a new anticipative strategy based on a multiple response-partial least squares model (called PLS2-prediction) are examined as post-DOE…
"Facta non verba" : an experiment on pledging and giving
2015
International audience; We design an experiment to investigate whether asking people to state how much they will donate to a charity (i.e., to pledge) increases their actual donation. Individuals’ endowment is either certain or a random variable. We study different types of pledges, namely, private, public and irrevocable, which differ in terms of the cost to the individual for not keeping the promise. We show that in absence of endowment uncertainty, private and public pledges are associated with lower donations as compared to donations in the no-pledge case: private pledges slightly reduce donations and public pledges reduce them more significantly. Donations increase with uncertainty (in…
Studio delle prestazioni di giunzioni incollate ibride (Strength evaluation of structural hybrid bonded joints)
2013
The idea of “hybrid joints” arises from the need of joining together materials, producing a tough, stiff and lightweight joint. The core concept is: use two different joining techniques, with the aim to increase the strength and gather the advantages of each technique, reducing the drawbacks. In this work hybrid joints consist in joints produced with two different kinds of joining techniques: one of them being adhesive bonding and the other being one among Resistance Spot Welding, Pop Riveting, Clinching, Self Piercing Riveting. The performance of hybrid joints are compared with those of traditional joints for the single lap joint geometry, for different geometric (plates thickness, pitch o…
A Robustness Approach to Reliability
2012
Reliability of products is here regarded with respect to failure avoidance rather than probability of failure. To avoid failures, we emphasize variation and suggest some powerful tools for handling failures due to variation. Thus, instead of technical calculation of probabilities from data that usually are too weak for correct results, we emphasize the statistical thinking that puts the designers focus on the critical product functions. Making the design insensitive to unavoidable variation is called robust design and is handled by (i) identification and classification of variation, (ii) design of experiments to find robust solutions, and (iii) statistically based estimations of proper safe…