Neural Network Control of a Laboratory Magnetic Levitator

Magnetic levitation (maglev) systems are nowadays employed in applications ranging from non-contact bearings and vibration isolation of sensitive machinery to high-speed passenger trains. In this chapter a mathematical model of a laboratory maglev system was derived using the Lagrangian approach. A linear pole-placement controller was designed on the basis of specifications on peak overshoot and settling time. A 3-layer feed-forward Artificial Neural Network (ANN) controller comprising 3-input nodes, a 5-neuron hidden layer, and 1-neuron output layer was trained using the linear state feedback controller with a random reference signal. Simulations to investigate the robustness of the ANN control scheme with respect to parameter variations, reference step input magnitude variations, and sinusoidal input tracking were carried out using SIMULINK. The obtained simulation results show that the ANN controller is robust with respect to good positioning accuracy

Effect of layer thickness on thermal properties of multilayer thin films produced by PVD

Cr/CrN/CrAlN, CrN/CrAlN and Cr/CrN thin layers were deposited by PVD (Physical Vapor Deposition). The multilayers were obtained from the combined deposition of different layers Cr, CrN and CrAlN thick films on on AISI4140 steel and silicon substrates at 200 °C, and evaluated with respect to fundamental properties such as structure and thermal properties. Cr, CrN and CrAlN single layers were also prepared for comparison purposes. The structural and morphological properties of PVD layers were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) coupled with EDS + WDS microanalyses, stresses were determined by the Newton’s rings methods using the Stoney’s equation and surface hardening and hardness profiles were evaluated by micro hardness measurements. The XRD data and HRTEM showed that both the Cr/CrN, CrN/CrAlN and Cr/CrN/CrAlN multilayer coatings exhibited B1NaCl structure with a prominent reflection along (200) plane, and CrAlN sub-layer microstructures composed of nanocrystallites uniformly embedded in an amorphous matrix. The innovation of this work was to use the thickness of three different coating types to determine the thermal properties. Furthermore, an empirical equation was developed for the thermal properties variations with temperature of AISI4140 steel coated with different multilayer coatings. The thermal conductivity of CrAlN single layered was lower than the multilayer and the bulk material AISI4140. Moreover, the influences of structure and composition of the multilayer coatings on the thermal properties are discussed. The thermal conductivity of nanoscale thin film is remarkably lower than that of bulk materials because of its various size effects.The authors wish to thank the Regional Council of Burgundy and EGIDE for their financial support, and also the technical staff of the Arts et Métiers ParisTech of Cluny: especially Romaric Masset and Pierre-Michel Barbier for the samples preparation

Exchange Rate Management within the Middle East and North Africa Region:The Cost to Manufacturing Competitiveness

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Contiguous redshift parameterizations of the growth index

The growth rate of matter perturbations can be used to distinguish between different gravity theories and to distinguish between dark energy and modified gravity at cosmological scales as an explanation to the observed cosmic acceleration. We suggest here parameterizations of the growth index as functions of the redshift. The first one is given by $\gamma(a)=\tilde\gamma(a) \frac{1}{1+(a_{_{ttc}}/a)}+\gamma_{_{early}} \frac{1}{1+(a/a_{_{ttc}})}$ that interpolates between a low/intermediate redshift parameterization $\tilde\gamma(a)=\gamma_{_{late}}(a)= \gamma_0 + (1-a) \gamma_a$ and a high redshift $\gamma_{_{early}}$ constant value. For example, our interpolated form $\gamma(a)$ can be used when including the CMB to the rest of the data while the form $\gamma_{_{late}}(a)$ can be used otherwise. It is found that the parameterizations proposed achieve a fit that is better than 0.004% for the growth rate in a $\Lambda$CDM model, better than 0.014% for Quintessence-Cold-Dark-Matter (QCDM) models, and better than 0.04% for the flat Dvali-Gabadadze-Porrati (DGP) model (with $\Omega_m^0=0.27$) for the entire redshift range up to $z_{_{CMB}}$. We find that the growth index parameters $(\gamma_0,\gamma_a)$ take distinctive values for dark energy models and modified gravity models, e.g. $(0.5655,-0.02718)$ for the $\Lambda$CDM model and $(0.6418,0.06261)$ for the flat DGP model. This provides a means for future observational data to distinguish between the models.Comment: 7 pages, 6 figures, matches PRD accepted versio

Figures of merit and constraints from testing General Relativity using the latest cosmological data sets including refined COSMOS 3D weak lensing

We use cosmological constraints from current data sets and a figure of merit (FoM) approach to probe any deviations from general relativity (GR) at cosmological scales. The FoM approach is used to study the constraining power of various combinations of data sets on modified gravity (MG) parameters. We use recently refined HST-COSMOS weak-lensing tomography data, ISW-galaxy cross correlations from 2MASS and SDSS LRG surveys, matter power spectrum from SDSS-DR7 (MPK), WMAP7 temperature and polarization spectra, BAO from 2DF and SDSS-DR7, and Union2 compilation of supernovae, in addition to other bounds from H_0 measurements and BBN. We use 3 parametrizations of MG parameters that enter the perturbed field equations. In order to allow for variations with redshift and scale, the first 2 parametrizations use recently suggested functional forms while the third is based on binning methods. Using the first parametrization, we find that CMB + ISW + WL provides the strongest constraints on MG parameters followed by CMB+WL or CMB+MPK+ISW. Using the second parametrization or binning methods, CMB+MPK+ISW consistently provides some of the strongest constraints. This shows that the constraints are parametrization dependent. We find that adding up current data sets does not improve consistently uncertainties on MG parameters due to tensions between best-fit MG parameters preferred by different data sets. Furthermore, some functional forms imposed by the parametrizations can lead to an exacerbation of these tensions. Next, unlike some studies that used the CFHTLS lensing data, we do not find any deviation from GR using the refined HST-COSMOS data, confirming previous claims in those studies that their result may have been due to some systematic effect. Finally, we find in all cases that the values corresponding to GR are within the 95% confidence level contours for all data set combinations. (abridged)Comment: 18 pages, 6 figures, matches version published in PR

Comparison of phosphatidylcholines containing one or two docosahexaenoic acyl chains on properties of phospholipid monolayers and bilayers

AbstractDocosahexaenoic acid (DHA) is the longest and most unsaturated of the n − 3 fatty acids found in membranes. Although a number of membrane properties have been demonstrated to be affected by the presence of this fatty acid, its mode of action has yet to be clearly elucidated. Prior reports on biological membranes have not distinguished the effect of mono-docosahexaenoyl phospholipids from those caused by phospholipids containing docosahexaenoic acid in both chains. This report compares properties of monolayers and bilayers composed of either 1-stearoyl-2-linolenoyl-sn-glycero-3-phosphocholine (as a control), 1-stearoyl-2-docosahexaenoyl-sn-glycero-3-phosphocholine or 1,2-di-docosahexaenoyl-sn-glycero-3-phosphocholine. When compared to the mono-DHA phosphatidylcholine (PC), the di-DHA PC occupies a much larger area/molecule, supports a more fluid and permeable bilayer, and is less susceptible to peroxidation. Monolayers made from either phospholipid are not condensable by cholesterol. We suggest many of the membrane properties linked to the presence of DHA may be the result of phospholipids which have lost their normal positional selectivity and have incorporated DHA into both positions

Evaluation of 2.1µm DFB lasers for space applications

This paper presents the results obtained in the frame of an ESA-funded project called “Screening and Preevaluation of Shortwave Infrared Laser Diode for Space Application” with the objective of verifying the maturity of state of the art SWIR DFB lasers at 2.1µm to be used for space applications (mainly based on the occultation measurement principle and spectroscopy). The paper focus on the functional and environmental evaluation test plan. It includes high precision characterization, mechanical test (vibration and SRS shocks), thermal cycling, gamma and proton radiation tests, life test and some details of the Destructive Physical Analysis performed. The electro-optical characterization includes measurements of the tuning capabilities of the laser both by current and by temperature, the wavelength stability and the optical power versus laser current

The role of spirituality and religiosity in psychoactive substance use among adolescents in a Nigerian Hospital

Objective: Adolescence is a transition period where drug experimentation is common. Spirituality and religiosity have been recognized by literature as having a possible role in stabilizing good physical and mental health. To compare the religiosity and spirituality among adolescents abusing a psychoactive substance and those not abusing psychoactive substances in a Nigerian hospital Methods: This was a cross-sectional descriptive study conducted among adolescent patients admitted to the drug rehabilitation unit and adolescents attending the General Outpatient Department of the ABUAD Multisystem Hospital, Ado-Ekiti. The Daily Spiritual Experience Scale and Centrality of Religiosity Scale were used Results: The prevalence of high religiosity and spirituality among the respondents was 57.9% and 56.1%. The prevalence of high religiosity and spirituality among respondents not abusing psychoactive substances was 62.9% and 62.6% respectively, while the level of high spirituality and religiosity among respondents abusing psychoactive substances was 53.0% and 49.1% respectively. A significant proportion of the respondents who had a low level of religiosity (55.9%) abused psychoactive substances than respondents who do not abuse psychoactive substances (45.7%) (X2=7.694 p=0.006). Similarly, more proportion of respondents who had a low level of spirituality (57.4%) abused psychoactive substances than respondents who do not abuse psychoactive substances (44.2%). The observation is statistically significant (X2=11.1, p<0.001). In addition, there was a significant positive correlation between the spirituality and religiosity scores among the respondents (r =0.50, p<0.001)  Conclusion: Psychoactive drug use among the respondent was associated with both low religiosity and spirituality. Therefore, religious activities should be encouraged among adolescents

Insights Into Unveiling a Potential Role of Tertiary Lymphoid Structures in Metastasis

Tertiary lymphoid structures (TLSs) develop in non-lymphatic tissue in chronic inflammation and cancer. TLS can mature to lymph node (LN) like structures with germinal centers and associated vasculature. TLS neogenesis in cancer is highly varied and tissue dependent. The role of TLS in adaptive antitumor immunity is of great interest. However, data also show that TLS can play a role in cancer metastasis. The importance of lymphatics in cancer distant metastasis is clear yet the precise detail of how various immunosurveillance mechanisms interplay within TLS and/or draining LN is still under investigation. As part of the tumor lymphatics, TLS vasculature can provide alternative routes for the establishment of the pre-metastatic niche and cancer dissemination. The nature of the cytokine and chemokine signature at the heart of TLS induction can be key in determining the success of antitumor immunity or in promoting cancer invasiveness. Understanding the biochemical and biomechanical factors underlying TLS formation and the resulting impact on the primary tumor will be key in deciphering cancer metastasis and in the development of the next generation of cancer immunotherapeutics

A time-frequency analysis of the Canadian macroeconomy and the yield curve

We use wavelet analysis to study the relationship between the yield curve and macroeconomic indicators in Canada. We rely on the Nelson-Siegel approach to model the zero coupon yield curve, and use the Kalman lter to estimate its time-varying factors: the level, the slope and the curvature. Apart from the bidirectional yield-macro relation, the paper broadens the existing literature by exploring the link between the monetary policy and the yield curve.COMPETE 2020, Portugal 2020, FEDER, FCTinfo:eu-repo/semantics/publishedVersio