oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2020 ( 3 )

2019 ( 12 )

2018 ( 15 )

2017 ( 14 )

Custom range...

Search Results: 1 - 10 of 6311 matches for " Nicolas Duget "
All listed articles are free for downloading (OA Articles)
Page 1 /6311
Display every page Item
Preparation and Catalytic Properties of Various Oxides and Mesoporous Materials Containing Niobium and Sulfate Ions, in the Etherification Reaction of 2-Naphtol  [PDF]
Alaa H. Hussein, Hiba Nahas, Mohamad Jahjah, Mourtada Srour, Rabih Jahjah, Nicolas Duget, Marc Lemaire, Daoud Naoufal
International Journal of Organic Chemistry (IJOC) , 2018, DOI: 10.4236/ijoc.2018.81002
Abstract: Several types of solid acid catalysts were prepared based on oxides like (ZrO2, TiO2, HfO2, MCM-41 and SBA-15), using two main preparation methods: the precipitation and the sol-gel methods. Each catalyst was subjected to two types of impregnations: sulfate ions using sulfuric acid as precursor and niobium using niobium oxalate as precursor. These prepared catalysts were tested in the etherification reaction of 2-naphtol, where the catalysts showed both acidic and redox properties. The acidic character was manifested through the formation of 2-butoxynaphtalene (with moderate yields) when oxide is sulfated, and the redox character (when impregnated with niobium) manifested through the formation of the interesting product 2-ethylnaphtofuran (with low yields) and other products that were a result of oxidative coupling of two 2-naphtol molecules (binol and acetal of binol). However despite the effort, several attempts to increase the yield of 2-ethylnaphtofuran did not work. All products prepared were obtained in pure form and characterized by 1H and 13C NMR, GC and MS.
Catalytic Properties of Various Oxides and Mesoporous Materials Containing Niobium and Sulfate Ions, in the Oxidation Reaction of 1-Octanol  [PDF]
Alaa H. Hussein, Ahmad Khalil, Mohamad Jahjah, Mourtada Srour, Rabih Jahjah, Nicolas Duget, Marc Lemaire, Daoud Naoufal
International Journal of Organic Chemistry (IJOC) , 2018, DOI: 10.4236/ijoc.2018.81003
Abstract: Several types of solid acid catalysts were prepared based on oxides like (ZrO2, TiO2, HfO2, MCM-41 and SBA-15). Each catalyst was subjected separately to two types of impregnations: sulfate ions and niobium. The catalytic activity of these solids was tested in the oxidation reaction of 1-octanol. These catalysts showed acidic and redox characters. MCM-41 and SBA-15 materials showed higher redox catalytic activities through the formation of (octyl octanoate, peroxyacetal and octanal). Our interest was focused on obtaining the ester (octyl octanoate) with high yields.
The Future of Benthic Indicators: Moving up to the Intertidal  [PDF]
Nicolas Spilmont
Open Journal of Marine Science (OJMS) , 2013, DOI: 10.4236/ojms.2013.32A008
Abstract:

The use of benthic indicators has increased dramatically during the last decades. The number of articles published on the subject, as well as the number of citations, has been particularly increasing since the early 90’s, notably in relation with the implementation of directives for the management of aquatic/marine ecosystems such as the Water Framework Directive and the Marine Strategy Framework Directive. Current benthic indicators suffer from severe drawbacks and their practical use is still discussed and might have reached a dead end. Indicators based on species composition are not totally satisfactory, mainly because they exhibit a high spatio-temporal variability (e.g. variable at both seasonal and pluri-annual scales) and are user-dependent (e.g. divergent results from US orEuropeexperts.) In turn, modifications of behaviour, metabolism, phenotype or stable isotopes composition in invertebrates usually occur at short time scales, compared to detectable changes in community composition, and makes their use particularly relevant as indicators of perturbation. It is argued in this paper that these functional indicators might be relatively quickly implemented in the intertidal, and represent an effective alternative to current benthic indicators.

Cerebral Networks of Interfacial Water: Analogues of the Neural Correlates of Consciousness in a Synthetic Three-Shell Realistic Head Model  [PDF]
Nicolas Rouleau, Michael Persinger
Journal of Signal and Information Processing (JSIP) , 2014, DOI: 10.4236/jsip.2014.54017
Abstract: The physical properties of water, particularly the nature of interfacial water and pH shifts associated with dynamics of the hydronium ion near any surface, may be a primary source of the complex electromagnetic patterns frequently correlated with consciousness. Effectively all of the major correlates of consciousness, including the 40 Hz and 8 Hz coupling between the cerebral cortices and hippocampal formation, can be accommodated by the properties of water within a specific-shaped volume exposed to a magnetic field. In the present study, quantitative electroencephalographic activity was measured from an experimental simulation of the human head constructed using conductive dough whose pH could be changed systematically. Spectral analyses of electrical potentials generated over the regions equivalent to the left and right temporal lobes in humans exhibited patterns characteristic of Schumann Resonance. This fundamental and its harmonics are generated within the earth-ionospheric cavity with intensities similar to the volumetric intracerebral magnetic (~2 pT) and electric field (~6 × 10-1 V·m-1) strengths. The power densities for specific pH values were moderately correlated with those obtained from normal human brains for the fundamental (first) and second harmonic for the level simulating the cerebral cortices. Calculations indicated that the effective pH would be similar to that encountered within a single layer of protons near the plasma membrane surface. These results reiterate recent measurements in a large population of human brains showing the superimposition of Schumann power densities in QEEG data and indicate that intrinsic features of proton densities within cerebral water may be a fundamental basis to consciousness that can be simulated experimentally.
Local Electromagnetic Fields Exhibit Temporally Non-Linear, East-West Oriented 1 - 5 nT Diminishments within a Toroid: Empirical Measurement and Quantitative Solutions Indicating a Potential Mechanism for Excess Correlation  [PDF]
Nicolas Rouleau, Michael Persinger
Journal of Electromagnetic Analysis and Applications (JEMAA) , 2015, DOI: 10.4236/jemaa.2015.72003
Abstract: States of excess correlation have previously been achieved at macroscopic levels by simultaneously exposing two non-local spaces to weak electromagnetic field patterns, generated by toroids, presented in a sequence such that the angular velocity of the field is modulated by changes in frequency over time. Here we systematically investigated effects upon the local space at the center of a single toroid generating the excess correlation sequence. The results indicated that a 1 - 5 nT diminishment in field intensity on the Y- or east-west axis was characteristic of the excess correlation sequence which was not indicated for control conditions. Statistically significant shifts in field intensity approximately 40 to 60 s before the onset of the first field associated with the excess correlation sequence indicated a temporally non-linear effect which converged upon the ratio of g and the rotational velocity of the Earth for the local space where Coriolis-like forces were inferred. Intensity shifts associated with the excess correlation sequence but not controls were quantitatively convergent upon parameters of the hydrogen line (1.42 GHz). Implications for these findings were discussed in relation to Mach’s principle and, in particular, to the electron as a physical unit which was found to relate classical and quantum systems.
Recent Trends in Occupational Injuries and Diseases in Argentina: A Panel Data Approach  [PDF]
Valentina Viego, Nicolas Sagui
Occupational Diseases and Environmental Medicine (ODEM) , 2015, DOI: 10.4236/odem.2015.34007
Abstract: Occupational injuries pose major public health and development related problems. However, efforts towards identification of determinants of labor incidents among salaried workers are still scarce in developing countries. This study aimed to identify sector and time effects on occupational accidents and diseases among Argentinean workers during 2004-2013. A negative binomial panel data model is estimated based on official data on injuries and fatalities in workplaces collected by the Board of Occupational Risks. Business cycle and profitability indicators are used as explanatory variables. Estimations also are adjusted by sector and time effects. Argentina business cycle tends to be negatively related with occupational injuries rates. In contrast, accidents at work reported tend to exhibit longer losses in working days. We also find a positive relationship between profitability and fatal injuries. These results may suggest incentives for under reporting and lower investments in safety by more profitable activities, which can imply some level of endogeneity between profit rate and occupational injuries.
A Conservative Model for Nonlinear Dynamics in a Stratified, Rotating Fluid  [PDF]
Nicolas Filatoff, Xavier Carton
Open Journal of Marine Science (OJMS) , 2018, DOI: 10.4236/ojms.2018.82013
Abstract:
We present a set of equations describing the nonlinear dynamics of flows constrained by environmental rotation and stratification (Rossby numbers Ro∈[0.1,0.5] and Burger numbers of order unity). The fluid is assumed incompressible, adiabatic, inviscid and in hydrostatic balance. This set of equations is derived from the Navier Stokes equations (with the above properties), using a Rossby number expansion with second order truncation. The resulting model has the following properties: 1) it can represent motions with moderate Rossby numbers and a Burger number of order unity; 2) it filters inertia-gravity waves by assuming that the divergence of horizontal velocity remains small; 3) it is written in terms of a single function of space and time (pressure, generalized streamfunction or Bernoulli function); 4) it conserves total (Ertel) vorticity in a Lagrangian form, and its quadratic norm (potential enstrophy) at the model order in Rossby number; 5) it also conserves total energy at the same order if the work of pressure forces vanishes when integrated over the fluid domain. The layerwise version of the model is finally presented, written in terms of pressure. Integral properties (energy, enstrophy) are conserved by these layerwise equations. The model equations agree with the generalized geostrophy equations in the appropriate parameter regime. Application to vortex dynamics are mentioned.
Two-dimensional graphic representation and analysis of learners’ traces
Nicolas Delestre,Nicolas Malandain
STICEF , 2007,
Abstract: The learner follow-up in problem solving is a hard issue. It is more difficult when there are a lot of learners or when those learners use distance learning. We propose in this paper a two-dimensional graphic representation of student's traces. To achieve this goal, we use and modify numerical analysis algorithms (automatic dimensionality reduction algorithms like Self Organizing Map and Stochastic Neighbour Embedding). We also propose a new distance between sets whose elements have semantic similarity. Finally, we validate and improve our algorithm with simulated data and experimental data
Experimental neck muscle pain impairs standing balance in humans
Nicolas Vuillerme,Nicolas Pinsault
Physics , 2009, DOI: 10.1007/s00221-008-1639-7
Abstract: Impaired postural control has been reported in patients with chronic neck pain of both traumatic and non-traumatic etiologies, but whether painful stimulation of neck muscle per se can affect balance control during quiet standing in humans remains unclear. The purpose of the present experiment was thus to investigate the effect of experimental neck muscle pain on standing balance in young healthy adults. To achieve this goal, 16 male university students were asked to stand upright as still as possible on a force platform with their eyes closed in two conditions of No pain and Pain of the neck muscles elicited by experimental painful electrical stimulation. Postural control and postural performance were assessed by the displacements of the center of foot pressure (CoP) and of the center of mass (CoM), respectively. The results showed increased CoP and CoM displacements variance, range, mean velocity, and mean and median frequencies in the Pain relative to the No pain condition. The present findings emphasize the destabilizing effect of experimental neck muscle pain per se, and more largely stress the importance of intact neck neuromuscular function on standing balance.
Partial list of bipartite Bell inequalities with four binary settings
Nicolas Brunner,Nicolas Gisin
Physics , 2007, DOI: 10.1016/j.physleta.2008.01.052
Abstract: We give a partial list of 26 tight Bell inequalities for the case where Alice and Bob choose among four two-outcome measurements. All tight Bell inequalities with less settings are reviewed as well. For each inequality we compute numerically the maximal quantum violation, the resistance to noise and the minimal detection efficiency required for closing the detection loophole. Surprisingly, most of these inequalities are outperformed by the CHSH inequality.
Page 1 /6311
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.