On ADE Quiver Models and F-Theory Compactification

Based on mirror symmetry, we discuss geometric engineering of N=1 ADE quiver models from F-theory compactifications on elliptic K3 surfaces fibered over certain four-dimensional base spaces. The latter are constructed as intersecting 4-cycles according to ADE Dynkin diagrams, thereby mimicking the construction of Calabi-Yau threefolds used in geometric engineering in type II superstring theory. Matter is incorporated by considering D7-branes wrapping these 4-cycles. Using a geometric procedure referred to as folding, we discuss how the corresponding physics can be converted into a scenario with D5-branes wrapping 2-cycles of ALE spaces.Comment: 21 pages, Latex, minor change

Toric Calabi-Yau supermanifolds and mirror symmetry

We study mirror symmetry of supermanifolds constructed as fermionic extensions of compact toric varieties. We mainly discuss the case where the linear sigma A-model contains as many fermionic fields as there are U(1) factors in the gauge group. In the mirror super-Landau-Ginzburg B-model, focus is on the bosonic structure obtained after integrating out all the fermions. Our key observation is that there is a relation between the super-Calabi-Yau conditions of the A-model and quasi-homogeneity of the B-model, and that the degree of the associated superpotential in the B-model is given in terms of the determinant of the fermion charge matrix of the A-model.Comment: 20 pages, v2: references adde

Numerical evaluation of a novel double-concentric swirl burner for sulfur combustion

A burner system for the efficient and clean combustion of sulfur is introduced, which serves as a key component in a novel solar power cycle using sulfur as chemical storage medium of solar energy. In order to validate the proposed design concept, highly-resolved numerical simulations have been performed. The current setup is operated with a thermal load of 20 kW or power density of 5 MW/m$^{3}$. Two nozzle configurations with different swirl intensities (SI) of the airflow are studied. A large inner recirculation zone is observed for the nozzle with a high SI (HSI), which leads to a strong radial dispersion of the sulfur spray and a broad, short flame in the combustion chamber; although this HSI design is beneficial from the viewpoint of flame stabilization, it causes a large number of sulfur droplets hitting the chamber wall. In contrast, the nozzle design with a low SI (LSI) yields a narrow spray and a long jet flame, with much less droplets hitting the wall. The HSI nozzle shows an overall higher flame temperature compared with the LSI nozzle, which is confirmed to be caused by burning at a higher local fuel equivalence ratio. This is attributed to the strong inner recirculation flow generated by the high swirl intensity, which results in an enhanced evaporation and mixing of sulfur droplets with air. In terms of operability and NOx emission, the LSI burner is preferred due to less sulfur droplets hitting the chamber wall and the lower flame temperature

(Z)-2-benzylidene-2H-[1, 4] benzothiazin-3-one(T1) as New Synthesized Corrosion Inhibitor for Mild Steel in 0.5 M H2SO4

The corrosion inhibition of mild steel in 0.5 M H2SO4 solution by (Z)-2-benzylidene-2H-[1,4]benzothiazin-3-one: (T1)  has been studied using electrochemical polarization , electrochemical impedance spectroscopy (EIS) and weight loss methods. The corrosion inhibition efficiency measured by all the three techniques was in good agreement with each other. The results showed that T1 is a very good inhibitor for mild steel in acidic media. The inhibition efficiency increases with increasing inhibitor concentration. It acts as a mixed-type inhibitor. EIS plots indicated that the addition of T1 increases the charge-transfer resistance (Rct), decreases the double-layer capacitance (Cdl) of the corrosion process, and hence increases inhibition efficiency. The adsorption of the T1 on the mild steel surface in acid solution obeys the Langmuir adsorption isotherm

Infection à l’Herpèsvirus équin de type 1 et 4

Equine herpesvirus type 1 (EHV-1) and type 4 (EHV-4) are ubiquitous equine pathogens, causing significant economic losses in the equine industry. EHV-1 is associated with several clinical forms of disease, including respiratory infection, infectious abortion, neonatal death and equine herpesvirus myeloencephalopathy (EHM). Whereas EHV-4, is predominantly associated with respiratory disease but can cause sporadic cases of abortion. The current review covers the different aspects of the disease, including its epidemiology, pathogenesis, clinical signs and preventive measures. The aim of this paper is to help the veterinarian to understand the disease in order to establish the required preventive and control measures. Keywords: EHV-1/EHV-4, epidemiology, pathogenesis, clinical signs, diagnosis, treatment, preventionLes Herpèsvirus Equin de type 1 (HVE-1) et de type 4 (HVE-1) sont des agents pathogènes équins ubiquistes, engendrant chaque année des pertes économiques importantes au niveau de l’industrie équine. L’HVE-1 est responsable de plusieurs syndromes cliniques notamment des affections respiratoires, des avortements ou des mortalités néonatales et des encéphalomyélites. L’HVE-4, est quant à lui responsable d’atteintes respiratoires principalement mais aussi d’avortements sporadiques. Dans cet article nous présentons une revue bibliographique qui relate les différents aspects de la maladie, en passant par son épidémiologie, sa pathogénie et symptomatologie ainsi que ses mesures de prévention. L’objectif principal est d’aider le vétérinaire praticien à mieux comprendre la maladie afin d’avoir la bonne attitude lors du diagnostic, tout en appliquant les mesures nécessaires pour la prévention et le contrôle. Mots clés: HVE-1 /HVE-4, épidémiologie, pathogénie, signes cliniques, diagnostic, traitement, préventio