Higher Order Combustion Instability Corrections for Solid Rocket Motors

Acoustic instability is currently viewed as one of the major challenges facing Solid Rocket Motor (SRM) developers. Unaccounted for, this phenomenon can induce undesirable pressure waves traveling in both longitudinal and transverse directions inside a rocket combustion chamber. Whenever the amplitude of these waves becomes large, intense vibrations and fluctuating loads can be experienced. These undesirable oscillations can lead to structural damage or outright motor failure. This work constitutes a follow-up to a recent study by Flandro and Majdalani 39 who have analyzed the linear aspects of this problem earlier last year. The current study builds on what their work has established, and expands the results that they have produced. The main benefit lies in the addition of few new terms which help to improve our predictive capabilities using explicit integral expressions. The current work considers two combustion chamber geometries. These correspond to the cylindrical and rectangular port perforations associated with an internal burning cylinder and slab motors, respectively. This study not only provides accurate and reliable approximations, but goes further to study the effects of key chamber parameters and their bearing on stability

Evidence of Bioactive Compounds from Vernonia polyanthes Leaves with Topical Anti-Inflammatory Potential

Vernonia polyanthes Less. (Asteraceae), popularly known as “assa-peixe”, is a plant species used in Brazilian traditional medicine for the treatment of cutaneous damage, cicatrization, inflammation, and rheumatism. Based on these ethnopharmacological findings, the current study evaluated the topical anti-inflammatory effects of the hexane (HEVP) and ethyl acetate (EAEVP) extracts from V. polyanthes leaves in experimental models of skin inflammation. Chemical characterization was carried out by HPLC–UV/DAD analysis. Anti-inflammatory activity was evaluated using Croton oil-, arachidonic acid (AA)-, phenol-, ethyl phenylpropiolate (EPP)-, and capsaicin-induced ear edema models in mice. Histopathological evaluation and measurements of myeloperoxidase (MPO) and N-acetyl-β-d-glucosaminidase (NAG) enzymes were also performed. Rutin, luteolin, and apigenin were identified in EAEVP. Topically applied HEVP and EAEVP significantly (p < 0.05, p < 0.01 or p < 0.001) reduced edema induced by five different irritants at the doses tested (0.1, 0.5 and 1.0 mg/ear). Histopathological analysis revealed a reduction of edema, inflammatory cell infiltration, and vasodilation. In addition, the enzymes activity (MPO and NAG) in the ear tissues was reduced by the topical treatment of HEVP and EAEVP (p < 0.05, p < 0.01 or p < 0.001). The results suggest that V. polyanthes leaves are effective against cutaneous damage, which support its traditional use and open up new possibilities for the treatment of skin disorders

FAZIA: A new performing detector for charged particles

The FAZIA apparatus is a new detector designed for the Fermi energy domain for charged particles based on three stages telescopes: Silicon detector (300 μm thick), Silicon detector (500 μm thick) and CsI(Tl) (10 cm). Using the ΔE-E technique and the Pulse Shape Analysis (PSA) it permits the charge and mass discrimination up to more than Z=20. In the following, some details about the FAZIA detectors and electronics, their performance and the frst experimental campaigns already performed will be discussed

FAZIA: a new performing detector for charged particles

International audienceThe FAZIA apparatus is a new detector designed for the Fermi energy domain for charged particles based on three stages telescopes: Silicon detector (300 μm thick), Silicon detector (500 μm thick) and CsI(Tl) (10 cm). Using the ΔE-E technique and the Pulse Shape Analysis (PSA) it permits the charge and mass discrimination up to more than Z=20. In the following, some details about the FAZIA detectors and electronics, their performance and the frst experimental campaigns already performed will be discussed