830 research outputs found

    Study of the Biological Activities of the Seeds of the Plant Ceratonia Siliqua L. Recovered in the Bejaia Region

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    Background: Ceratonia siliqua is a plant that belongs to the Fabaceae family. It is frequently used in our culinary and medical traditions to fight cholesterol, acute diarrhea and digestive disorders. Methods: The hydrogen atom or electron donation abilities of the corresponding extracts and some pure compounds were measured from the bleaching of the purple-colored methanol solution of 2, 20-diphenylpicrylhydrazyl (DPPH), studying the anti-inflammatory effect by measuring the volume of the edema of the paw that has received carrageenan 1%. Antimicrobial activity in vitro was screened by using disc diffusion and micro-dilution methods. Results: The determination of the polyphenols of the methanolic extracts of the seeds reveals the richness of our extracts in polyphenols is 30 mg of gallic acid / g of extract. The aqueous and methanolic extract flavonoid assay shows that they contain high levels of flavonoids with contents of 07 and 10 mg equivalent of quercetin / g of extract respectively. The aqueous and methanolic extracts of Ceratonia siliqua seeds from the Bejaia region could bring the stable free radical 2.2 diphenyl-1-picrylhydrazyl (DPPH) to yellow-colored diphenylpicrylhydrazine with respective IC 50 values of 0.7 mg/ml and 0.2 mg/ml. They exhibit lower antioxidant activity than ascorbic acid (0.038 μg / ml). Determination of anti-inflammatory activity revealed that our aqueous and methanolic extracts of Ceratonia siliqua L seeds are able to reduce edema up to 81.89%. The methanoid extracts of Ceratonia siliqua L. seeds have a medium antibacterial action against bacteria: E. coli (13 mm), Staphylococcus aureus (12 mm) and Pseudomonas aeruginosa (12 mm). On the other hand, the aqueous extracts of the seeds of Ceratonia siliqua L have a weak antibacterial action against the same bacteria with a diameter of inhibition of 9 mm. However, the aqueous extracts of Ceratonia siliqua L seeds are endowed with a very important inhibitory action against candida albicans and it is similar to that of the antibiotic, antifungal Econazole (1%). Conclusion: According to the results observed, the two extracts of the seeds and pods have a potential anti-free radical and antioxidant measured compared to the standard antioxidant used. The results of the antimicrobial activity carried out in vitro on the 3 bacterial strains indicate that the two methanolic extracts of this plant have low antibacterial activity

    Full Scale Proton Beam Impact Testing of new CERN Collimators and Validation of a Numerical Approach for Future Operation

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    New collimators are being produced at CERN in the framework of a large particle accelerator upgrade project to protect beam lines against stray particles. Their movable jaws hold low density absorbers with tight geometric requirements, while being able to withstand direct proton beam impacts. Such events induce considerable thermo-mechanical loads, leading to complex structural responses, which make the numerical analysis challenging. Hence, an experiment has been developed to validate the jaw design under representative conditions and to acquire online results to enhance the numerical models. Two jaws have been impacted by high-intensity proton beams in a dedicated facility at CERN and have recreated the worst possible scenario in future operation. The analysis of online results coupled to post-irradiation examinations have demonstrated that the jaw response remains in the elastic domain. However, they have also highlighted how sensitive the jaw geometry is to its mounting support inside the collimator. Proton beam impacts, as well as handling activities, may alter the jaw flatness tolerance value by ±\pm 70 μ{\mu}m, whereas the flatness tolerance requirement is 200 μ{\mu}m. In spite of having validated the jaw design for this application, the study points out numerical limitations caused by the difficulties in describing complex geometries and boundary conditions with such unprecedented requirements.Comment: 22 pages, 17 figures, Prepared for submission to JINS

    Effect of kinetic façades on energy efficiency in office buildings - hot dry climates

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    In hot dry climates excess solar gain may result in high cooling energy consumption and indoor discomfort; sun control and shading devices is an important aspect of many energy-efficient building design strategies. Advanced CAD systems that integrate computational tools, such as parametric design systems, make possible and explore ways to formulate a responsive building envelope that could interact with sun position. The parametric design provides innovative building envelopes, which are more adaptive and interactive by actively responding to prevailing weather conditions, for enhancing energy performance and indoor thermal comfort levels. This study attempts to examine and evaluate the effect and performance of smart façades in the context of the indoor thermal comfort and energy efficiency. These parameters are achieved by controlling the levels of solar radiation and by calculating shading element sizes for sun control in response to environmental changes. In order to ensure the systems autonomy the semi-transparent PV modules has been used as panel's material. The method is applied to the case study of a reference office building with a fixed glazed façade windows-to-wall ratio in hot arid climate zone of Algeria, in particular the city of Biskra (latitude 34.6N). The results obtained from modeling simulation, using GECO- grasshopper (parametric plugin for Rhinoceros), shown That kinetic facades equipped with PV modules have greatly influenced in a positive way the indoor air temperature, thermal and visual comfort levels and also, work towards a better environment for the inhabitants instead of simply being the part that separates the interior from the exterior

    The chemical bond in external electric fields: energies, geometries, and vibrational Stark shifts of diatomic molecules

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    Publisher's version/PDFIt is shown that the response of molecular properties of diatomics such as the total energy, the bond length, and the vibrational Stark shift to an external homogenous electric field (EF) can be predicted from field-free observable properties such as the equilibrium bond length, the bond dissociation energy, the polarizability and dipole moment functions, and the vibrational frequency. Delley [J. Mol. Struct.: THEOCHEM 434, 229 (1998)] suggested to approximate the potential energy surface under an EF by a Morse function augmented with a EF term proportional to the internuclear separation. In this work, this term is replaced by the expression of the field-induced energy change which yields a field-perturbed Morse potential that tends to a constant asymptotic limit when the EF term itself become proportional to the sum of the polarizabilities of the separated atoms. The model is validated by comparison with direct calculations on nine diatomics, five homo-nuclear (H[subscript 2], N[subscript 2], O[subscript 2], F[subscript 2], and Cl[subscript 2]) and four hetero-nuclear (HF, HCl, CO, and NO), covering a range and combinations of dipole moments and polarizabilities. Calculations were conducted at the quadratic configuration interaction with single and double excitations (QCISD) and density functional theory (DFT)-B3LYP levels of theory using the 6-311++G(3df,2pd) basis set. All results agree closely at the two levels of theory except for the Stark effect of NO which is not correctly predicted by QCISD calculations as further calculations, including at the coupled cluster with single and double excitation (CCSD) level of theory, demonstrate

    Nonlinear Blind Identification with Three-Dimensional Tensor Analysis

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    This paper deals with the analysis of a third-order tensor composed of a fourth-order output cumulants used for blind identification of a second-order Volterra-Hammerstein series. It is demonstrated that this nonlinear identification problem can be converted in a multivariable system with multiequations having the form of +=. The system may be solved using several methods. Simulation results with the Iterative Alternating Least Squares (IALS) algorithm provide good performances for different signal-to-noise ratio (SNR) levels. Convergence issues using the reversibility analysis of matrices and are addressed. Comparison results with other existing algorithms are carried out to show the efficiency of the proposed algorithm

    Second T = 3/2 state in 9^9B and the isobaric multiplet mass equation

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    Recent high-precision mass measurements and shell model calculations~[Phys. Rev. Lett. {\bf 108}, 212501 (2012)] have challenged a longstanding explanation for the requirement of a cubic isobaric multiplet mass equation for the lowest A=9A = 9 isospin quartet. The conclusions relied upon the choice of the excitation energy for the second T=3/2T = 3/2 state in 9^9B, which had two conflicting measurements prior to this work. We remeasured the energy of the state using the 9Be(3He,t)^9{\rm Be}(^3{\rm He},t) reaction and significantly disagree with the most recent measurement. Our result supports the contention that continuum coupling in the most proton-rich member of the quartet is not the predominant reason for the large cubic term required for A=9A = 9 nuclei
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