Faculté des Sciences exactesكلية العلوم الدقيقةhttp://hdl.handle.net/123456789/1325182022-05-28T14:15:54Z2022-05-28T14:15:54ZPhysique du LHC et extensions du modèle standard.Taibi, HamzaAissaoui, Habibhttp://hdl.handle.net/123456789/1373602022-05-19T10:18:31Z2022-03-10T00:00:00ZPhysique du LHC et extensions du modèle standard.
Taibi, Hamza; Aissaoui, Habib
Though very successful at describing a wide variety of particle physics
phenomenons, the standard model leaves some proprieties of nature unexplained. This fact lead physicists to search for new solutions based on extended symmetries or extra degree of freedoms. In this thesis we focus on two of the new physics proposal, the unparticle model and the left right symmetric model. We begin by presenting the theoretical framework upon which unparticle are founded, conformal field theory. Then, we describe briefly the original formulation of the unparticle model by Georgi and subsequent works relevant to our study. Next, we construct a gauged unparticle model charged under the standard model electroweak group SU(2)×U(1). Any new physics model must be compatible with the standard model predictions. In this regard the electroweak precision tests represent a powerful tool to check the compatibility of new physics model with experimental data. For the gauged unparticle model we calculate the oblique parameters S and T that parametrize the contribution of new physics states to electroweak observables. We then use the bound for these parameters extracted from LEP and other experiments to constrain the parameters space of unparticles. Finally, we consider the effects of left right symmetric model spectrum on the muon anomalous magnetic moment and use it to decrease the deviation between the SM predictions and experimental observations . A paper describing part of the results of this dissertation has been published in the Journal Modern Physics Letters A, entitled: ”Constraints on electroweak gauged unparticle model from the oblique parameters S and T”
2022-03-10T00:00:00ZContributions aux problèmes variationnels et aux inclusions différentielles dans les espaces de Banach.Bounekhel, DjalalKechkar, Nasserdinehttp://hdl.handle.net/123456789/1373592022-05-19T10:16:02Z2021-11-03T00:00:00ZContributions aux problèmes variationnels et aux inclusions différentielles dans les espaces de Banach.
Bounekhel, Djalal; Kechkar, Nasserdine
The thesis consists in three chapters. In the first one, we state all needed definitions and concepts
and some preliminary results. In Chapter 2, we study the existence of solutions for nonconvex
quasi-variational problems in smooth reflexive Banach spaces. The third chapter is devoted to the
study of existence of solutions for nonconvex state dependent sweeping processes in smooth
reflexive Banach spaces. At the end of the thesis, we state a conclusion of all obtained results
together with a list of some open problems that may interest the researchers in the field.
2021-11-03T00:00:00ZContribution à l’étude numérique de la convection sous serres fermées et ouvertes.Slatni, YassineDjezzar, Mahfoudhttp://hdl.handle.net/123456789/1373572022-05-19T10:08:40Z2021-11-01T00:00:00ZContribution à l’étude numérique de la convection sous serres fermées et ouvertes.
Slatni, Yassine; Djezzar, Mahfoud
The author proposes in this work, the numerical study of the natural convection
phenomenon, in a closed and open greenhouse, also a numerical study of the phenomenon of
mixed convection, in an open double-chapel greenhouse, crossed laterally by a forced flow in
steady and laminar regime. These two types of greenhouse are filled with a Newtonian and
incompressible fluid. The number of Prandtl is fixed at 0.702 (case of air).
For the tunnel greenhouse, using the Boussinesq approximation and the vorticity-stream
function formulation, the flow is modelled by partial differential equations: the continuity and
the momentum equations expressed in a system of coordinates known as ""Bicylindric». We
took conditions of heating and ventilation as: Isothermal walls for our greenhouse (TH for
tubes, TM near heating tubes and TC for the roof, with TH> TM>TC).the convect4e flow is
governed by different control parameters, namely Rayleigh number (Ra), 103≤Ra≤103, tubes
number (Nt), 1≤Nt≤7 and the form factor (f), 0<f≤1. Also three positions of natural openings
(Ps) are taken into consideration as well as their opening dimensions (Dm).
The guideline equations written in bicylindrical coordinates were discretized using the
finite volume method and the vorticity-stream function formulation; the resultant algebraic
equations were solved using the successive over relaxations method. Concerning the
calculation code validation, our results and those of the literature are in very good agreement.
The influences of physical and geometric parameters were examined. In the first case of the
closed greenhouse with heating tubes, the Rayleigh number effect on the heat transfer was
examined for a fixed number of tubes as a reference (Nt=3), the number of tubes was
subsequently modified, to see its influence on the heat transfer in the greenhouse, this on the
one hand, on the other hand, the geometry system effect on the natural convection phenomenon
on the greenhouse was also taken into account. On the other hand, in the second case, where we
studied numerically the natural convection in an open greenhouse, containing two openings in
the roof, we examined the opening position effect with three different positions, as well as the
opening size effect on the heat transfer and the climate inside the greenhouse tunnel.
For the open double-chapel greenhouse, we took as heating conditions for our greenhouse
(TH for the ground and TC for the roof, with TH>TC).
The equations governing this phenomenon, discretized by the finite volume method, were
solved numerically with a commercial code Fluent. We examined the effect of the parameters
that characterize the heat transfer, and the flow structure. Several situations have been
considered by varying the Rayleigh number (103≤Ra≤105) and the Reynolds number
(10≤Re≤500).
2021-11-01T00:00:00ZIsolement et détermination structurale de métabolites secondaires d’espèces des genres Santolina et Centaurea (Asteraceae) - Activités biologiques.Labed, FatihaBenayache, Fadilahttp://hdl.handle.net/123456789/1373562022-05-17T09:38:58Z2019-12-19T00:00:00ZIsolement et détermination structurale de métabolites secondaires d’espèces des genres Santolina et Centaurea (Asteraceae) - Activités biologiques.
Labed, Fatiha; Benayache, Fadila
This work is part of the research program established by our research unit which consists in the phytochemical investigation of Algerian medicinal plants belonging to families known for their richness in secondary metabolites with potential biological activities. In this context, two species were selected: Santolina chamaecyparissus and Centaurea pungens, given their belonging to the family Asteraceae whose richness in bioactive compounds is well established. Known mainly for their essential oils, the aerial parts of S. chamaecyparissus (leaves + flowers) were macerated in 70% ethanol. After filtration, concentration and dilution with distilled water, the obtained hydroalcoholic extract is subjected to successive extractions by solvents of increasing polarity (CHCl3, AcOEt and n-BuOH) to give the three corresponding derivative extracts. Our experiments concerned the CHCl3 and n-BuOH extracts and focused on the determination of the total phenols of the two extracts and then the evaluation of their antioxidant activity by the DPPH radical reduction and TEAC tests. The results showed that the n-BuOH extract is richer in phenolic compounds and is better antioxidant than the CHCl3 extract in the DPPH radical scavenging assay with vitamin C as positive control. In the TEAC test, the results were in agreement with those of the DPPH radical test, in fact the n-BuOH extract showed a significant and similar activity to that of quercetin 3-O-glucoside used as positive control.
Following these encouraging results, both extracts were subjected to chromatographic techniques
and 15 compounds were isolated. The structures of 14 of these compounds were determined.
These are 5 flavone aglycones including 4 methoxylated; 3 glycosylated flavones, 2 of which were new for Santolina genus; 2 megastigmane glucosides new for Asteraceae family; 2 phenylpropanoids new for the genus Santolina and 2 cyanogenic compounds also new for the genus Santolina. The phytochemical investigation of Centaurea pungens (Flowers) conducted by similar methods as reported for S. chamaecyparissus, allowed the isolation of 9 pure products: 3 sesquiterpene lactones, 2 of which were described for the first time in the literature, 2 methoxylated flavones, 3 glucosylated flavones and a derivative of quinic acid. In order to validate the use of C. pungens in traditional medicine, the antimicrobial activity of the 9 isolated compounds was assessed against Gram-positive strains: Bacillus cereus, Staphylococcus aureus and Listeria innocua, and Gramnegative strains: Pseudomonas aeruginosa and Pseudomonas fragi.
2019-12-19T00:00:00Z