We calculate the trajectory of a moving object on earth and the trajectory of the earth around the sun in a fourdimensional space (x, y, z, t). We see that the trajectory has a mass: this is what is called dark matter which mass depends on the mass of the moving object. Indeed the deformation of space, the track, deviates light as we are at the hypersurface of the universe, and that is the method of measurement of the 'mass' of the universe.

If we use the Friedmann-Lemaitre-Robertson-Walker model for avacuum dominated universe, we see that time may be a function ofa length, the so called co-moving distance. In the FLRW model, thisfunction is injective, so for each time t there is one co moving distancea(t). Straightforwardly, we can assume that time has the dimensionof a length, even if, in a fourdimensional universe, the four dimensionsare not isotropic. Taking account of this hypothesis, we can solve theEPR paradox for entangled states. Moreover, a simple model of antimatter can also be made: antimatter deforms the universe inwardswhile matter deforms the universe outwards. Dark matter is alsodeduced to be a track of massive moving objects within the local curvature of the universe. And finally, taking account that our universeis fourdimensional and that time may be the fourth dimension andhas the dimension of a length, the mystery of dark energy is solved.Indeed, in a fourdimensional universe, what we call dark energy hasa positive pressure which comes naturally from the expansion of theuniverse.

For three different sizes of graphene nanosheets, we computed the Density of states when these nanosheets are progressively doped with an increasing percentage of Si atoms. The pure graphene nanosheets are semi conducting or not depending on their size. The pure silicene nanosheets are conducting with a conduction due to π electrons. The Si doped graphene nanosheets are also semi conducting or not depending on their size: for small sizes, there are semi conducting and they become conducting for larger sizes and larger percentages of Sidoping. We computed also the total electronic energy which is linked to the mechanical stability of all our nanosheets. This mechanical stability decreases regularly as a function of the Si percentage of doping , but for the pure silicene nanosheets, the mechanical stability decreases more abruptly.

We noticed that the first family of fermions and the Higgs boson have masses which are equal to integer powers of 2 in eV/c 2 units (i.e. in the Planck length units). We made the hypothesis that, if spacetime is composed of small hypercubes of one Planck length edge, it exists elementary wavefunctions which are equal to √ 2 exp(ikx i) if it corresponds to a space dimension or equal to √ 2 exp(iωt) if it corresponds to a time dimension. By using the Dirac propagation equation and combinatorics we showed that the electron has a mass of 2 19 eV/c 2 , the quark has a mass of 2 21 eV/c 2 and the electron neutrino has a mass of 2eV/c 2. Finally, the Higgs boson is showed to have a mass of 2 37 eV/c 2

Silica ionogels were synthesized from tetramethoxysilane (T MOS ),methyltrimethoxysilane (MT MS ) and 1-ethyl- 2-methylimidazolium Acetate (EMI MAc: Ionic Liquid) in different proportions .The textural characterizations showed an effect of these concentrations on the corresponding aerogels: pore size distributions and effective surfaces. The structure of the aerogels was measured with a SAXS (Small- Angle XRay Scattering) apparatus and was typical of acid catalyzed aerogels. Conductivity voltage measurements, operated on the ionogels, were carried out using an electrical 4 wire-electrodes set up. The electrical voltage temporal response of the EMIMAc silica ionogel was modelled by a RLC series circuit which characteristics depended on the synthesis.

We noticed that the first family of fermions and the Higgs boson have masses which are equal to integer powers of 2 in $eV/c^2$ units (i.e. in the Planck length units). We made the hypothesis that, if spacetime is composed of small hypercubes of one Planck length edge, it exists elementary wavefunctions which are equal to $\sqrt{2} \exp (ikx_i)$ if it corresponds to a space dimension or equal to $\sqrt{2} \exp (i \omega t)$ if it corresponds to a time dimension. By using the Dirac propagation equation and combinatorics we showed that the electron has a mass of $2^{19}eV/c^2$, the quark has a mass of $2^{21}eV/c^2$ and the electron neutrino has a mass of $2eV/c^2$. Finally, the Higgs boson is showed to have a mass of $2^{37}eV/c^2$.

We made the hypothesis that our universe is fourdimensional: time $t$ is treated as a 'regular' dimension. So in the $(t,x,y,z)$ coordinates system, we present a simple approach of all the elementary particles which might be four,three and two-dimensional. This hypothesis leads to a unified approach of all particles.