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This paper describes an experimental and theoretical approach to evaluate cycloid drive reducer efficiency. The tests are carried out on 7.5 kW two-disc cycloid drive with a gear ratio of 19. The torque and speed are measured on the input and output shaft. The efficiency is calculated based on the obtained results. The main goal of the second part of the study is to deduce equations of cycloid reducer in order to predict and analyze experimental results. In this way, the following points are set for the simulation: a working condition in which the input speed and the output load are imposed; then, the output speed is determined by the gear ratio, and finally, the input torque is obtained by solving the dynamic problem. A new model for cycloidal reducers is proposed. This model is based on kinematics and dynamics of rigid bodies and a non-linear stiffness based on contact dynamics. The overall elasticity effects are all condensed between the input shaft and the cycloidal disk. The proposed model allows to predict the efficiency for several operational conditions and offer a drastic reduction of computational costs suitable for the optimization process.

In the automotive industry, high-speed elecrical engines will be used in a very large range of speeds, leading to non-stationary operating conditions. Thus more critical speeds may be crossed a very large number of times during the whole life-time of the engine. Therefore, estimating accurately the non-stationary loads and deformations during these transient regimes is of first importance for a correct design. In this paper, we propose a novel dynamic model for unbalanced high-speed rotors with less restrictive assumptions. The finite element model accounts for flexion, torsion and traction-compression leading to six degrees of freedom on each node. The non-ideal energy source is considered and the rotor is running under non-stationary operating conditions and crossing supercritical speeds. The angular displacement is defined in such a way that it combines simultaneously the intrinsic nominal rotation and the torsional deformation. The comparison of the proposed model with other models under different assumptions on the energy source and on the bending-torsion coupling shows that our model offers more accurate prediction for both lateral and torsional vibrations when crossing critical speeds. The ability of the proposed model to account for the mutual influence between lateral and torsional behavior is highlighted and is exhibited through time-frequency analyses.

International audience; This study is concerned with spatial visualisation and its possible inferences as a necessary ability in French engineering education. It is completed as part of a French research programme, which aims at better understanding how multi-purpose 3-D modelling software is used by learners at different levels of schooling. Spatial ability may be measured thanks to paper tests and predicts choices and success in science, technology, engineering, and mathematics education and professions. It is often described as an ability composed of two factors, namely spatial orientation and spatial visualisation. The latter can be further developed into mental rotation and mental transformation. In order to evaluate the spatial visualisation skills of first-year students in a French engineering school specialised in mechanics, the Revised Purdue Spatial Visualization Tests: Visualization of Rotations, the Mental Rotation Test, which both aim at measuring mental rotation, and the Mental Cutting Test, which aims at measuring mental transformation, were administered to 137 engineering freshmen in September 2018. This data collection was completed with a selection of demographics and academic assessment scores. The purpose of this article is to explore, by carrying out an analysis of variance, how these students’ spatial visualisation skills can be related to individual characteristics and how they contribute to academic performance.

The growing use of rotating machines operating in non-stationary conditions gave rise to a greater need to a higher precision for describing their dynamic behavior. The latter has always been based on a certain number of simplifying assumptions. In particular, the spinning speed is considered either constant or following a given law of variation as a function of time, resulting in a dynamic model that is limited to specific operating conditions. The aim of this work is to present a more general dynamic model of rotating machines, which accurately reflects its behavior in real working conditions. No assumption is made on the speed of rotation; it is included as an unknown of the dynamic problem by introducing a degree of freedom combining both the free body rotation and the torsional deformation. The instantaneous angular speed (IAS) is then deduced not only from the induced torque, but also from the whole dynamic behavior of the structure taking into account the periodic geometry (e.g.: gears, bearings) as well as the operating conditions (e.g.: going through the critical speeds). Making no assumption on the angular speed leads to a new formulation of the gyroscopic effect strongly present at very high speeds. This new formulation shows a coupling between the different degrees of freedom as well as a nonlinear behavior of the structure. The results of both classic and new formulations are compared for an architecture of a rotating machine to highlight the utility of the innovative approach in non-stationary operating conditions.

A multiphysics model of smoothed contact surface hemispherical contact under dynamic vibration stress is treated in this paper. The contact structure is applied to hemispherical conductor bulk materials. The structure electrothermomechanical (ETM) behavior is investigated based on the Hertz contact theory coupled with electrokinetic approach. An electrical circuit integrating the contact material properties is proposed. The contact surface deformation ETM expression is formulated. The transient variations of the contact conductor material temperatures in function of the mechanical vibrations are analytically described. The ETM parameters range versus the mechanical load stress is analyzed by considering aluminum alloy material hemispherical bulk with a radius varying from 10 μ m to 1 mm. The contact radius can be totally deformed when the load is increased up to 20 kN. In addition, an innovative multiphysics computational method is validated numerically to determine the transient variation of the contact surface radius model from SPICE simulation by considering 0.5 kHz/1 kHz frequency presenting 0.5-kN amplitude sine wave, and arbitrary waveform dynamic vibrations. It was conjectured from numerical application, the hemispherical bulk contact temperature, and also the mechanism multiphysics phenomena governing the structure behavior. As ongoing research, the equivalent system tensorial statement illustrating the multiphysics interaction between the conductor contacts will be developed.

Speed reducers with input shafts spinning at very high speeds (up to 42 000 rpm) are generally associated to electric motors, which are more and more used especially in the automotive field, in order to bring the rotational speed to the most efficient window. Accurate modeling of those rotating machinary behavior is crucial to improve product reliability and to prolong machinery life. Many studies are conducted with an imposed angular speed, which is in most of the cases considered as constant or, in best cases, which follows a given variation law. In this paper, the study is performed with no assumption on the rotational speed. A variable driving torque is induced to the input shaft and the instantaneous angular speed (IAS) is deduced from the dynamic problem coupled to an angular approach. As a result, the IAS takes into account not only the induced torque perturbations but also the periodic geometry of the whole structure (e.g.: bearings and gears). The aim of this work is to extend the existing model based on the Finite Element Method by introducing an enhancement of the gyroscopic effect matrices without any assumption on the spinning speed. This model will lead to the introduction of coupling between the flexural and torsional degrees of freedom as well as to a non-linearity in the modeling of the studied system. The aim is to improve the accuracy of simulations for the rotor dynamics in non-stationary conditions especially when getting through critical speeds.

International audience; This chapter deals with the damping caused by friction in joints. A new test bench is presented and justified by comparisons made with devices described in the literature. The purpose of this academic bench is to measure the damping induced by partial slip and friction in a planar joint. A new method for the so-called stopped-sine excitation was developed. It allows more precise monitoring of the evolution of the vibration frequency and damping of nonlinear modes, and it allows uncoupling normal static and dynamic tangential forces. This method is associated with piezoelectric exciters for greater efficiency when stopping excitation. A large number of experimental results are presented and discussed, which are used to characterize the damping induced by micro-sliding in the bonds.

This work deals with payload vibration insulation in aeronautic applications. The main objective is to design stabilization devices for optical devices. To achieve this goal, polymer materials have been used because they provide damping and flexibility in order to isolate the optical devices from vibrations and shocks. This kind of material exhibit a mechanical behavior that strongly dependent on the temperature, the strain amplitude and the frequency. The purpose of this paper is to give a new identification method of the viscoelastic parameters based on the Oberst beam test. The aim is to carry out the dependence of the elastomer mechanical properties on the strain amplitude. By coupling this test with Dynamic Mechanical Analysis, it is possible to obtain the mechanical behavior of viscoelastic material according to the strain amplitude and the frequency. To achieve this goal, the experiment derived from the Oberst beam set-up and ASTM E756-05. The time response signal is post-processed using nonlinear unconstraint optimization method in order to identify the instantaneous frequency and damping ratio of the first eigenmode. Then, it is possible to recover the storage modulus and the loss factor of the polymer according to the strain amplitude using a finite element model of the setup. Finally, the identified frequency and amplitude dependent models are taken into account to carry out numerical simulations on the whole mechanical device.

Problem- and project-based learning approaches place the students at the center of the learning processes and give the opportunity to make the students active and involved. It also prepares the students for their future professional life by placing them in real situations with different stakeholders. The assessments implemented during problem and project phases allow to evaluate the acquisition of disciplinary skills and competences. This kind of teaching and learning also provides the opportunity to develop specific project skills giving more autonomy and agility to the students in complex problem solving. Knowing their level of acquisition of these skills is a key point for the students, making them more confident in face of the problems they have to solve. All these aspects have been widely experienced and are well documented. ISMEP-Supmeca, a French public engineering school, has chosen since decades to engage in problem-and project-based learning. Progressively, this approach developed through various axis, including educational research projects (IDEFI PLACIS, Erasmus+ strategic partnerships EPICES and EBCC). There are now three offers of this kind at ISMEP-Supmeca: one problem-based learning module for first year students, and two project-based learning modules for second and last year students. Moreover, a self-assessment process has been implemented in order to enable the students to self-assess their project mode skills. Students realize one self-assessment at the beginning of the module and one at the end. In the first one, they evaluate their skills before working with others and receiving feedback, whereas in the second one, their assessment results from the experience gained during the module. This paper presents the first results and the perspectives of this self-assessment experiment, which will continue to be developed.

International audience; It is well known that the friction between interfaces at bolted joints plays a major role in the characterization of damping. Friction can be either induced by macroslip or microslip. The aim of this chapter is to model and quantify the dissipated energy by microslip in the joints in order to compute the damping ratio. It is assumed that the coefficient of friction between the nominally flat surfaces is constant and that friction is the only source of energy dissipation. An experimental study is reported to measure static normal load and dynamic tangential load without any coupling between these two main directions. A rheological contact model, Extended Greenwood Model (EGM), based on microcontacts and statistical distributions is developed and studied. Experimental results and simulations are compared in order to assess and discuss the model.

International audience; This paper deals with the use of piezoelectric patches for nonlinear dynamic identification. The patches are glued on the structure to identify amplitude-dependent damping and natural frequency; their positions are defined in order to perform the excitation concentrated on the first bending mode. Their locations on the structure allow to perform ”stop sines” tests, as, unlike electrodynamic shakers, piezos are embedded on structures and do not modify the studied structure after the excitation signal is switched off. Although, despite the piezo and the stop-sine, the signal is still modulated by other frequency components or polluted by random signals, a post processing with the extended Kalman Filter allows a very good determination of the modal damping and the natural frequency, especially when they depends on the free vibration amplitude.

AIP Publishing; International audience; This study aims to present a novel work aimed at locating discrete nonlinearities in mechanical assemblies. The long term objective is to develop a new metric for detecting and locating nonlinearities using Scanning LDV systems (SLDV). This new metric will help to improve the modal updating, or validation, of mechanical assemblies presenting discrete and sparse nonlinearities. It is well established that SLDV systems can scan vibrating structures with high density of measurement points and produc e highly defined Operational Deflection Shapes (ODSs). This paper will present some insights on how to use response phase mapping for locating nonlinearities of a bolted flange. This type of structure presents two types of nonlinearities, which are geometr ical and frictional joints. The interest is focussed on the frictional joints and, therefore, the ability to locate which joint s are responsible for nonlinearity is seen highly valuable for the model validation activities.

International audience; Due to their lightness, the aerospace structures are vulnerable to vibrations. Their amplitudes need to be mitigated through damping devices. The aim of this paper is to control the tightening force of a bolted joint in order to improve the vibration reduction. The work focuses on a single vibration mode modeled by two degrees of freedom coupled with a Jenkins’ cell. Then two control strategies are proposed in order to reduce the harmonically forced vibrations and transient vibrations. The first control law uses a constant optimum clamping for each excitation level. The second law consists in a sinusoidal variation of the clamping force adapted to each level and frequency of excitation. Finally, in the third section, the control law is modified in order to reduce transient vibrations. For each control law, the performances of the model are discussed according to the aimed application.

International audience; It is well known that bolted joints have significant influence on the dynamical behavior of assembled structures due to formation of damping. This paper focuses on damping caused by dry friction in a rotational joint. Friction can be either induced by micro-slipping or macro-slipping. This paper describes the design of a new experimental device intended to measure damping caused by friction and partial slip in rotational joints. An original method for measuring dissipated energy in rotational joints with plan-plan contact is proposed. This method is based on Lagrange formalism and allows to measure accurately forces and torques only with accelerometers. These techniques are available for very small displacements that occur in micro-slip and partial slip of surfaces in contact and are still available for large displacements (macro-slip). An analytical compact model based on the Greenwood model is studied. The experimental results and simulations used to quantify the dissipated energy in order to compute the damping ratio are presented and discussed.

The jointed structures are widely spread but their behaviour is quite hard to model and to simulate. The talk deals with a decomposition in linear and non-linear substructures that allows to make the simulations easier. The authors show that the modal subspace is not optimal to reduce the order of the model. Another choice of reduction subspace is shown to be more optimal as it requires less state-variables and leads to a better correlation with Full Order Models. Finally, the authors show how it is possible to characterize experimentally the joints by loading them in the reduction subspace and to integrate an experimental model in the reduce order simulations of the structure.

The thermodynamic contributions to duplex formation of all 32 possible single-nucleotide dangling ends on a Watson-Crick pair are reported. In most instances, dangling ends are stabilizing with free energy contributions ranging from +0.48 (GT(A)) to-0.96 kcal/mol (). In comparison, Watson-Crick nearest-neighbor increments range from -0. 58 (TA/AT) to -2.24 (GC/CG) kcal/mol. Hence, in some cases, a dangling end contributes as much to duplex stability as a Watson-Crick A-T base pair. The implications of these results for DNA probe design are discussed. Analysis of the sequence dependence of dangling-end stabilities show that the nature of the closing base pair largely determines the stabilization. For a given closing base pair, however, adenine dangling ends are always more or equally as stable as the other dangling nucleotides. Moreover, 5' dangling ends are more or equally as stabilizing as their 3' counterparts. Comparison of DNA with RNA dangling-end motifs shows that DNA motifs with 5' dangling ends contribute to stability equally or more than their RNA counterparts. Conversely, RNA 3' dangling ends contribute to stability equally or more than their DNA counterparts. This data set has been incorporated into a DNA secondary structure prediction algorithm (DNA MFOLD) (http://mfold2.wustl.edu/mfold/dna/for m1.cgi) as well as a DNA hybridization prediction algorithm (HYTHERtrade mark) (http://jsl1.chem.wayne.edu/Hyther/hythermenu .html).

In structural dynamics, the prediction of damping remains the biggest challenge. This paper deals with the energy losses caused by micro-slip in a nominally planar interface of a structure. This paper proposes an analytical and experimental study of flexural vibrations of a clamped-clamped beam with innovative position of the interfaces. The objective of this test bench is to characterize the global rheology of the interface. The proposed model aims to characterize this rheology based on local settings of the interface. First, the test bench is described and the choice of the position of the interface is justified. The experimental bench and the dynamic behavior of this structure are presented. We propose to illustrate the mechanism of energy losses by micro-slip by making a comparison between the behavior of a “monolithic” beam and a sectioned beam. Secondly, a modeling of the interface taking into account the surface defect is presented. The energy dissipated by friction in the interface is calculated during a loading cycle. This leads to a computation of the dissipated energy and thus to a nonlinear loss factor. Finally, we confront the loss factor calculated analytically and the measured one.

ASME 2013 International Design Engineering Technical Conferences and Computers and Information in Engineering ConferenceVolume 7B: 9th International Conference on Multibody Systems, Nonlinear Dynamics, and ControlConference Sponsors: Design Engineering Division, Computers and Information in Engineering DivisionISBN: 978-0-7918-5597-3; International audience; This work proposes a Compact Model Synthesis (CMS) for Partially Observed Operational Systems (POOS) without using the complete knowledge of models. Series of “grey boxes” fed with partial observations are built in order to synthesize target variables with compact models. The recursive process for real time computation is based on Kalman Filters (KF). This stochastic approach allows to converge in line toward deterministic models with estimated uncertainties and without intrusion on the complete model process. Mathematical context is described first and illustrated secondly with two examples.

This paper deals with the damping caused by friction in joints. A new test bench is presented and justified by comparisons made with devices described in the literature. The purpose of this academic bench is to measure the damping induced by partial slip and friction in a planar joint. Moreover, allows uncoupling normal static and dynamic tangential forces. A new method for so-called stopped-sine excitation was developed. It allows more precise monitoring of the evolution of the vibration frequency and damping of non-linear modes. This method is associated with piezoelectric exciters for greater efficiency when stopping excitation. A large number of experimental results are presented and discussed. They are used to characterize the damping induced by micro-sliding in the bonds.

This work is a contribution in the field of Operational Modal Analysis to identify the modal parameters of mechanical structures using only measured responses. The study deals with structural responses coupled with harmonic components amplitude and frequency modulated in a short range, a common combination for mechanical systems with engines and other rotating machines in operation. These harmonic components generate misleading data interpreted erroneously by the classical methods used in OMA. The present work attempts to differentiate maxima in spectra stemming from harmonic components and structural modes. The detection method proposed is based on the so-called Optimized Spectral Kurtosis and compared with others definitions of Spectral Kurtosis described in the literature. After a parametric optimization of the method, a critical study is performed on numerical simulations and then on an experimental structure in operation in order to assess the method’s performance.Copyright © 2011 by ASME

In structural dynamics, the problem of damping remains the biggest challenge. This paper deals with the energy losses caused by micro-slip in a planar interface of a structure. Taking into account friction in the joints during the analysis of dynamic systems remains a complex task. This paper proposes an analytical and experimental study of flexural vibrations of a clamped-clamped beam with innovative position of the interfaces. First, the benchmark is described and the choice of the position of the interface is justified. The displacement and stress fields are defined during each phase of the loading process in the joints under the assumption of quasi static motion. The energy dissipated by friction in the interface is calculated during a loading cycle. This leads to a definition of the dissipated energy, thus, to a non linear loss factor. The dynamic response of the beam is calculated using this non linear loss factor and a dissipative force is defined and used to predict the dynamic behaviour of the structure. In the last part of the paper, we present the experimental bench, and the dynamic behaviour of this structure. We propose to illustrate the mechanism of energy losses by micro-slip by making a comparison between the behaviour of the “monolithic” beam and the sectioned beam. Finally, we confront the loss factor calculated analytically and the measured one.Copyright © 2011 by ASME

International audience; The friction between interfaces at bolted joints plays a major role in the damping of structures. This paper deals with the energy losses caused by micro-slips in the joints. The aim of this study is to define in an analytical way these energy dissipation mechanisms which we examine through the analysis of a new benchmark: the flexural vibration of a clamped-clamped beam with original positioning of the interfaces. The joints exhibit the behavior of an interface under constant and uniform normal stress. The stress and strain values are computed at the joints under the assumption of quasi-static motion. This model allows us to understand the evolution of the slip and stick regions along the joint interfaces during the loading process. The expressions of the strain and stress fields during each phase of the loading process are derived. These lead to the quantification of the dissipated energy within the interface. Using this formula, a nonlinear loss factor can then be computed. In the final part of the paper, the dynamic response of the beam is calculated using this nonlinear loss factor.

After a description of existing experimental methods and models built on the dynamic behavior of friction forces between two solids, this paper presents an original new test bench and specific measurement techniques used to better define the accuracy of measurements. This test bench has been designed for a large range of tests in terms of static strain, dynamic excitation, frequency and kinds of surfaces. The second part describes the choice of the model which is a development of the Lugre model we have called “Frozen” Model. Methods for parametric identification are proposed and comparisons between experiments and simulations are presented. In the third part a critical analysis is carried out on the test bench and its applications. (This paper is a part of a study on the prediction of vibration level of space launchers - Ariane V program). A parametrical analysis was conducted to lead and conclude a study on the robustness of the chosen model.Copyright © 2009 by ASME

This paper deals with the energy losses caused by micro-slip in a planar interface of a structure. Taking into account friction in the joints during the analysis of dynamic systems remains difficult. This paper proposes an analytical study of flexural vibrations of a clamped-clamped beam, the novelty of this experiment is that the position of the interfaces has never been tested before to our knowledge. First, the authors described the benchmark and justified the choice of the position of the interfaces. The second section presents the displacement and stress fields during each phase of the loading process in the joints under the assumption of quasi static motion. In the third part, the authors calculated the energy dissipated by friction in the interface on a loading cycle. This leads to a definition of the energy dissipated by friction in the interface and thus to a non linear loss factor. This loss factor is then optimized according to the height of the beam. In the last part of the paper, the dynamic response of the beam is calculated using this non linear loss factor.Copyright © 2009 by ASME

Secondary structure motifs in nucleic acid probes generally impair intended hybridization reactions and so efforts to predict and avoid such structures are commonly employed in probe design schemes. Another key facet of probe design that has received much less attention, however, is that secondary structure at targeted probe binding site regions may also impair hybridization. Thus, evaluation of both probe and target site secondary structures together should improve hybridization prediction and design effectiveness. Several challenges confound this goal, including imperfect empirical rules and parameters underlying predictions and the fact that folding algorithms scale poorly with respect to sequence length. Here, we attempt to quantify the consequences of target site structure on predicted hybridization using sequences sampled from the human genome. We also provide a methodology for choosing a reasonable ''window size'' around target sites that is as small as possible without compromising folding algorithm prediction accuracy.

Motivation: Central to many molecular biology techniques as ubiquitous as PCR and Southern blotting is the design of oligonucleotide (oligo) probes and/or primers possessing specific thermodynamic properties. Here, we use validated theoretical methods to generate distributions of predicted thermodynamic properties for DNA oligos of various lengths. These distributions facilitate immediate appreciation of typical thermodynamic values for oligos of various lengths. Results: Distributions of melting temperature (Tm), free energy $$\left(\Delta {G}_{T}^{o}\right)$$, and fraction hybridized or fraction bound (Fb), are presented for oligos of length 10--50 bases sampled from the human genome. The effects of changing temperature, oligo and salt concentrations, constraining G+C content, and introducing mismatches are exemplified. Our results provide the first survey of typical and limiting thermodynamic values evaluated on a genomic scale. Described numbers comprise useful 'rules of thumb' that are applicable to most technologies dependent upon DNA oligo design. Contact: Koehlert@appliedbiosystems.com Supplementary information: Supplementary Data is available at http://bioinformatics.oxfordjournals.org

Thermodynamic measurements are reported for 51 DNA duplexes with A.A, C.C, G.G, and T.T single mismatches in all possible Watson-Crick contexts. These measurements were used to test the applicability of the nearest-neighbor model and to calculate the 16 unique nearest-neighbor parameters for the 4 single like with like base mismatches next to a Watson-Crick pair. The observed trend in stabilities of mismatches at 37 degrees C is G.GT.T approximately A.AC.C. The observed stability trend for the closing Watson-Crick pair on the 5' side of the mismatch is G.C/= C.G/= A.T/= T.A. The mismatch contribution to duplex stability ranges from -2.22 kcal/mol for GGC.GGC to +2.66 kcal/mol for ACT.ACT. The mismatch nearest-neighbor parameters predict the measured thermodynamics with average deviations of DeltaG degrees 37 = 3.3%, DeltaH degrees = 7. 4%, DeltaS degrees = 8.1%, and TM = 1.1 degrees C. The imino proton region of 1-D NMR spectra shows that G.G and T.T mismatches form hydrogen-bonded structures that vary depending on the Watson-Crick context. The data reported here combined with our previous work provide for the first time a complete set of thermodynamic parameters for molecular recognition of DNA by DNA with or without single internal mismatches. The results are useful for primer design and understanding the mechanism of triplet repeat diseases.

It is well known that the friction between interfaces at bolted joints plays a major role in the damping of assembly structures. Friction can be either induced by macro-slipping or micro-slipping. The aim of this paper is to model and quantify the dissipated energy by micro-sliding down to the scale of roughness between two flat surfaces in order to compute the damping ratio. It was assumed that the coefficient of friction between two materials is constant and that friction is the only source of energy dissipation. An experimental study was conducted to measure static normal load and dynamic tangential load without any coupling between these two main directions. A rheological contact model based on the Extended Greenwood Model with micro-contacts and statistical distributions was developed and studied. Experimental results and simulations are compared in order to assess and discuss the model.

We developed the SNPlex Genotyping System to address the need for accurate genotyping data, high sample throughput, study design flexibility, and cost efficiency. The system uses oligonucleotide ligation/polymerase chain reaction and capillary electrophoresis to analyze bi-allelic single nucleotide polymorphism genotypes. It is well suited for single nucleotide polymorphism genotyping efforts in which throughput and cost efficiency are essential. The SNPlex Genotyping System offers a high degree of flexibility and scalability, allowing the selection of custom-defined sets of SNPs for medium- to high-throughput genotyping projects. It is therefore suitable for a broad range of study designs. In this article we describe the principle and applications of the SNPlex Genotyping System, as well as a set of single nucleotide polymorphism selection tools and validated assay resources that accelerate the assay design process. We developed the control pool, an oligonucleotide ligation probe set for training and quality-control purposes, which interrogates 48 SNPs simultaneously. We present performance data from this control pool obtained by testing genomic DNA samples from 44 individuals. in addition, we present data from a study that analyzed 521 SNPs in 92 individuals. Combined, both studies show the SNPlex Genotyping system to have a 99.32% overall call rate, 99.95% precision, and 99.84% concordance with genotypes analyzed by TaqMan probe-based assays. The SNPlex Genotyping System is an efficient and reliable tool for a broad range of genotyping applications, supported by applications for study design, data analysis, and data management.

This study is concerned with spatial visualisation and its possible inferences as a necessary ability in French engineering education, and is completed as part of a French research programme, which aims at better understanding how multi-purpose 3-D modelling software is used by learners at different levels of schooling. Spatial visualisation is one of the components of spatial ability (McGee, 1979; Tartre, 1990; Uttal, Meadow, Tipton, Hand, Alden, Warren & Newcombe, 2013), which predicts choices and success in Science, Technology, Engineering, and Maths disciplines and professions (Wai, Lubinski & Benbow, 2009). Spatial visualisation can be further developed into mental rotation and mental transformation (Kersh & Cook, 1979, as cited in Tartre, 1990). In order to evaluate the spatial visualisation skills of first-year students in a French engineering school specialised in Mechanics, the Revised Purdue Spatial Visualization Tests: Visualization of Rotations (Yoon, 2011), the Mental Rotation Test (Vandenberg & Kuse, 1978), which both aim at measuring mental rotation, and the Mental Cutting T est (CEEB, 1939), which aims at measuring mental transformation, were administered to around 135 freshmen in September 2018. In the French Grande Ecole system, engineering students are recruited after a two-year preparation, which is equivalent to the first two years of a degree course. This data collection was completed with a selection of demographics and academic assessment scores. An analysis of variance revealed these spatial tests are significant predictors of the students’ success in mechanism analysis, Algorithmics and Applied mathematics. Given the malleability of spatial skills (Uttal et al., 2013), these findings open the way for remedial courses, which could increase students’ learning and success in engineering courses (Sorby, 2005)., Dans le cadre du projet e-FRAN EXAPP_3D, qui vise notamment à mieux comprendre l’utilisation d’outils numériques de conception, modélisation et simulation 3D à différents niveaux d’études et par différents publics, ce travail de recherche porte sur la visualisation spatiale et ses possibles inférences en matière d'habileté dans les études d’ingénierie. La visualisation spatiale est un composant de l’habileté spatiale, qui prédit les choix et la réussite dans les études et les professions dans le domaine des sciences, technologie, ingénierie et mathématiques (Wai, Lubinski & Benbow, 2009). La visualisation spatiale peut à son tour être subdivisée en deux nouvelles compétences, soit la rotation mentale et la transformation mentale (Kersh & Cook, 1979, cités par Tartre, 1990), qui peuvent être mesurée grâce à des tests papier. En septembre 2018, le Revised Purdue Spatial Visualization Tests: Visualization of Rotations (Yoon, 2011) et le Mental Rotation Test (Vandenberg & Kuse, 1978), qui visent à mesurer la rotation mentale, et le Mental Cutting Test (CEEB, 1939), qui vise à mesurer la transformation mentale, ont été administrés à environ 135 étudiants en première année d’école d’ingénieurs en mécanique, afin d’évaluer leur compétence de visualisation spatiale. Les étudiants intègrent Supméca sur concours après avoir suivi une classe préparatoire, une Licence 2 ou une Licence 3, ou obtenu un brevet de technicien supérieur ou un diplôme universitaire technique. En complément, une partie des notes individuelles du premier semestre d’enseignement a été recueille. L’étude de la relation entre la performance aux tests spatiaux et la performance académique des étudiants a révélé le pouvoir prédictif de ces tests dans les évaluations portant sur l’analyse des mécanismes, l’algorithmique et la programmation en langage C, et les mathématiques appliquées. La malléabilité des compétences spatiales étant établie (Uttal et al., 2013), des dispositifs de remédiation pour favoriser l'apprentissage et la performance des étudiants sont envisageables (Sorby, 2005).