Blade loss transient dynamics analysis, volume 1. Task 1: Survey and perspective

An analytical technique was developed to predict the behavior of a rotor system subjected to sudden unbalance. The technique is implemented in the Turbine Engine Transient Rotor Analysis (TETRA) computer program using the component element method. The analysis was particularly aimed toward blade-loss phenomena in gas turbine engines. A dual-rotor, casing, and pylon structure can be modeled by the computer program. Blade tip rubs, Coriolis forces, and mechanical clearances are included. The analytical system was verified by modeling and simulating actual test conditions for a rig test as well as a full-engine, blade-release demonstration

Advances on Applications of Bioactive Natural Compounds

This is a reprint of articles from the Special Issue published online in the open access journal Applied Sciences (ISSN 2076-3417) (available at: https://www.mdpi.com/journal/applsci/special issues/Bioactive Natural Compounds).info:eu-repo/semantics/publishedVersio

Secondary Metabolites and Their Applications

The identification of secondary metabolites present in both terrestrial and marine species continues to be a fundamental and privileged path for the emergence of new and fundamental natural products available on the market with very different applications. For example, aplidine is a new natural anticancer agent, and it was approved in Australia in 2018 to treat multiple myeloma and was isolated from the first time from tunicate “Aplidium albicans” Milne Edwards. (+)-Nootkatone is a natural sesquiterpene compound, found in very small amounts in several species such as “Chamaecyparis nootkatensis” (D. Don) Sudworth, ”Chrysopogon zizanioides” (L.) Roberty and “Citrus paradise” Macfad., which exhibits highly appreciated organoleptic properties and is, therefore, highly demanded as a flavoring agent or adjuvant in the food, pharmaceutical and perfumery industries. This same natural secondary metabolite is applied as insecticide and acaricide, and it was very recently authorized by United Sates Environmental Protection Agency to be include on formulations to control the spread of mosquitoes that transmit infectious diseases as dengue and zika. And who does not know the application of ascorbic acid, found for example in acerola and lemon fruits, as an antioxidant agent, widely used by the food industry? The successful application of secondary metabolites in diverse requests often involves the use of, more or less, complex mixtures of metabolites, extracted by different methods and from different natural sources, but whose chemical composition and active principles are perfectly established. For example, there are the defined botanical mixtures, called natural product botanicals, which are recognized by the FDA as medicinal entities, successfully used in clinical therapy for the treatment of various diseases. This is the case of the mixture of the secondary metabolites of ”Solanum sodomaeum” L., solamargine, solasonine, and mono- and di-glycosides derivatives of solasodine, approved by the European Medicine Agency (trade name Curaderm) for the treatment of basal cell carcinoma of the skin. One area in which the application of secondary metabolites mixtures rather than of pure compounds is common is in the formulation of biopesticides. For example, the insecticide Grandevo® is a mixture of metabolites produced in the fermentation of “Chromobacterium subtsugae”, which includes pigments from the violacein family and proteins that are repellent and antifeeding. Despite the great successes already achieved regarding the secondary metabolites’ identification and the development of new applications for these metabolites, this is an area of research that should not slow down. Research must continue identifying and isolating secondary metabolites in unexplored natural sources; new methodologies for extracting secondary metabolites should be tested and optimized to develop greener and more efficient processes; pure secondary metabolites and chemically characterized mixtures must be tested in different biological activities in order to enhance new applications responding to the growing needs of humanity. The Special Issue of Applied Sciences, “Advances in Applications of Natural Bioactive Compounds”, aims to contribute to the desired continuous advance in this scientific field, bringing together publications focused on the most recent advances in the identification of secondary metabolites from terrestrial and marine sources, in new extractive methodologies, and in proposals for applications that add value to natural resources and contributes to a more sustainable development.his study was financed by Portuguese National Funds, through FCT Fundação para a Ciência e Tecnologia, the European Union, QREN, FEDER, and COMPETE, through funding the cE3c center (UIDB/00329/2020), the LAQV-REQUIMTE (UIDB/50006/2020) and the CICS-UBI (UIDB/00709/2020 and UIDP/00709/2020).info:eu-repo/semantics/publishedVersio

Multiple scattering effects in quasi free scattering from halo nuclei: a test to Distorted Wave Impulse Approximation

Full Faddeev-type calculations are performed for $^{11}$Be breakup on proton target at 38.4, 100, and 200 MeV/u incident energies. The convergence of the multiple scattering expansion is investigated. The results are compared with those of other frameworks like Distorted Wave Impulse Approximation that are based on an incomplete and truncated multiple scattering expansion.Comment: 7 pages, 16 figures, to be published in Phys. Rev.

Blade loss transient dynamics analysis, volume 2. Task 2: Theoretical and analytical development. Task 3: Experimental verification

The component element method was used to develop a transient dynamic analysis computer program which is essentially based on modal synthesis combined with a central, finite difference, numerical integration scheme. The methodology leads to a modular or building-block technique that is amenable to computer programming. To verify the analytical method, turbine engine transient response analysis (TETRA), was applied to two blade-out test vehicles that had been previously instrumented and tested. Comparison of the time dependent test data with those predicted by TETRA led to recommendations for refinement or extension of the analytical method to improve its accuracy and overcome its shortcomings. The development of working equations, their discretization, numerical solution scheme, the modular concept of engine modelling, the program logical structure and some illustrated results are discussed. The blade-loss test vehicles (rig full engine), the type of measured data, and the engine structural model are described

Anaerobic granular sludge as a biocatalyst for 1,3-propanediol production from glycerol in continuous bioreactors

1,3-propanediol (1,3-PDO) was produced from glycerol in three parallel Expanded Granular Sludge Blanket (EGSB) reactors inoculated with granular sludge (control reactor-R1), heat-treated granular sludge (R2) and disrupted granular sludge (R3) at Hydraulic Retention Times (HRT) between 3 and 24 h. Maximum 1,3-PDO yield (0.52 mol mol-1) and productivity (57 g L-1 d-1) were achieved in R1 at HRTs of 12 h and 3 h, respectively. DGGE profiling of PCR-amplified 16S rRNA gene fragments showed that variations in the HRT had a critical impact in the dominant community of microorganisms. However, no appreciable differences in the bacterial population were observed between R2 and R3 at low HRTs. Production of H2 was observed at the beginning of the operation, but no methane production was observed. This study proves the feasibility of 1,3-PDO production in EGSB reactors and represents a novel strategy to valorise glycerol generated in the biodiesel industry

Production of 1,3-propanediol in EGSB reactors by open mixed cultures using glycerol as the carbon source

Two pre-treatments (granules disruption and heat) were applied to granular sludge to favour the production of 1,3-propanediol (1,3-PDO) from glycerol by non-methanogenic bacteria in expanded granular sludge blanket (EGSB) reactors. Different hydraulic retention times (HRT) were tested to achieve a maximum yield of 0.59 mol of 1,3-PDO/mol of glycerol in the control (no treatment) reactor at an HRT of 12 h. Molecular biology tools were used to evaluate the microbial community present in the inoculum and biomass for each HRT studied. Variations in the HRT had a critical impact in the dominant community of microorganisms. No appreciable differences in microbial population were observed between the reactors operated with heat–treated and disrupted granules at low HRTs. Additionally, the production of H2 was observed at the beginning of the operation, however this was associated with low production of 1,3-PDO. In turn, no methane production was observed. This study proves the feasibility of 1,3-PDO production in EGSB reactors, which have the advantage of being operated under non-sterile conditions and represent a novel strategy to valorise glycerol being generated as by-product in the biodiesel industry