299 research outputs found
Experimental study of thermal properties and dynamic viscosity of graphene oxide/oil nano-lubricant
No full textThis experimental study was carried out based on the nanotechnology approach to enhance the efficacy of engine oil. Atomic and surface structures of graphene oxide (GO) nanoparticles were investigated by using a field emission scanning electron microscope and X-ray diffraction. The nano lubricant was produced by using a two-step method. The stability of nano lubricant was analyzed through dynamic light scattering. Various properties such as thermal conductivity, dynamic viscosity, flash point, cloud point and freezing point were investigated and the results were compared with the base oil (Oil-SAE-50). The results show that the thermal conductivity of nano lubricant was improved compared to the base fluid. This increase was correlated with progressing temperature. The dynamic viscosity was increased by variations in the volume fraction and reached its highest value of 36% compared to the base oil. The cloud point and freezing point are critical factors for oils, especially in cold seasons, so the efficacy of nano lubricant was improved maximally by 13.3% and 12.9%, respectively, compared to the base oil. The flash point was enhanced by 8%, which remarkably enhances the usability of the oil. It is ultimately assumed that this nano lubricant to be applied as an efficient alternative in industrial systems
Analysis of a spontaneous mutant and selected clones of cv. Italia (Vitis vinifera L.) by AFLP markers
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Buoyancy driven flow characteristics inside a cavity equiped with diamond elliptic array
No full textThis study numerically investigates the two-dimensional natural convection in a square enclosure with an isothermal diamond elliptic array at Rayleigh numbers of 104 ≤ Ra ≤ 107. Three cases are considered, i.e., case 1 where two pairs of circular heating bodies are used inside the cavity, one is placed on the vertical centerline (VC) of the cavity and the other on the horizontal centerline (HC), case 2 where one pair of horizontal elliptic heating bodies is placed on the VC of the cavity and the other on the HC and case 3 where the horizontal elliptic heating bodies are replaced by vertical elliptic heating bodies. Numerical simulation was carried out based on the mesoscopic approach (LBM). The effects of the horizontally and vertically heated arrays were investigated. We demonstrate that, only when the Rayleigh number increases to Ra = 107, the numerical solutions reach an unsteady state for all cases. The transition of the flow regime from the unsteady state to the steady state depends on the variation in the ratio of the elliptical cylinder
Influenza del numero di polimorfismi del DNA sulla valutazione delle distanze genetiche in Vitis vinifera
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Estimates in the Hardy-Sobolev space of the annulus and stability result
No full textsummary:The main purpose of this work is to establish some logarithmic estimates of optimal type in the Hardy-Sobolev space ; of an annular domain. These results are considered as a continuation of a previous study in the setting of the unit disk by L. Baratchart and M. Zerner, On the recovery of functions from pointwise boundary values in a Hardy-Sobolev class of the disk, J. Comput. Appl. Math. 46 (1993), 255–269 and by S. Chaabane and I. Feki, Optimal logarithmic estimates in Hardy-Sobolev spaces , C. R., Math., Acad. Sci. Paris 347 (2009), 1001–1006. As an application, we prove a logarithmic stability result for the inverse problem of identifying a Robin parameter on a part of the boundary of an annular domain starting from its behavior on the complementary boundary part
Comparative analysis of genetic linkage maps and QTL information produced for grape (Vitis spp.)
No full textComposition, Insecticidal and Antifungal Activities of Tunisian Daucus setifolius Essential Oil
No full textPurpose: The present study aims to investigate for the first time, the chemical composition and biological profile of the essential oil extracted from Daucus setifolius harvested in northwest of Tunisia. Method: The content of the essential oil obtained after hydrodistillation of the aerial parts, was analyzed by gas chromatography-mass spectrometry (GC/MS). The anti-insect potency of D. setifolius essential oil was assessed against the most important and destructive insect pests of stored cereals in Tunisia namely Tribolium confusum and Sitophilus zeamais. Moreover, the oil was screened, using microdilution method, for its antifungal properties against Candida albicans and Candida glabrata yeasts and Trichophyton rubrum and Microsporum canis dermatophytes. Results: The chromatographic analysis proved its richness in monoterpene hydrocarbons (46.4%). Thus, sabinene (33.1%) was identified as the predominant compound, followed by β-selinene (14.4%) and terpinen-4-ol (8.6%). Indeed, the repellency assay indicated that the volatile oil exhibited a higher repellency towards both adult species (> 70%) after 120 min of exposure. The results showed that dermatophyte strains are more sensitive to D. setifolius essential oil compared to Candida spp. Conclusion: The essential oil of D. setifolius aerial parts has potential for development of plant-derived insecticidal compounds and repellents for stored grains insects. Graphical Abstract: [Figure not available: see fulltext.
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