Search results for "fluid"
showing 10 items of 5513 documents
ELEKTROMAGNĒTISKI IETEKMĒTU HIDRODINAMISKO PROCESU EKSPERIMENTĀLI PĒTĪJUMI ŠĶIDRU METĀLU NOSLĒGTOS TILPUMOS
2014
Elektroniskā versija nesatur pielikumus
Estimates for Divergence Velocities of Axially Moving Orthotropic Thin Plates
2014
Some models for axially moving orthotropic thin plates are investigated analytically via methods of complex analysis to derive estimates for critical plate velocities. Linearised Kirchhoff plate theory is used, and the energy forms of steady-state models are considered with homogeneous and inhomogeneous tension profiles in the cross direction of the plate. With the help of the energy forms, some limits for the divergence velocity of the plate are found analytically. In numerical examples, the derived lower limits for the divergence velocity are analysed for plates with small flexural rigidity. peerReviewed
Design of Reliable and Efficient Banki-Type Turbines
2020
A new shape for the external surface of the Crossflow turbine blades is proposed, which allows for the preservation of hydraulic efficiency in spite of a significant maximum blade thickness providing mechanic robustness and reliability. The final shape of the blades is assessed using an iterative solution for two uncoupled models: a 2D computational fluid dynamic (CFD) and a structural 3D finite element method (FEM) analysis of a single blade. Application of the proposed methodology to the design of a power recovery system (PRS) turbine, a new backpressure Crossflow-type inline turbine for pressure regulation, and energy production in a real Sicilian site follows.
The lipid composition, fluidity, and Mg2+-ATPase activity of rice (Oryza sativa L. cv. Bahia) shoot plasma membranes: effects of ABA and GA3
1992
Six-day-old rice plants (Oryza sativa L., cv Bahia) were grown for 5 days more in nutrient solution culture containing 10−5 M abscisic acid (ABA) or gibberellic acid (GA3) (treated plants). Plasma membrane (PM) vesicles were isolated from the shoots of treated or control plants, and ATPase hydrolytic and proton-pumping activity, fluidity, and free sterol and phospholipid composition were determined. Both treatments resulted in modified plant growth and increases in PM fluidity. The ATPase hydrolytic activity was decreased by 25% of control values with ABA treatment and by 35% with GA3. Both treatments reduced proton-pumping by 23%. GA3 treatment reduced the relative amount (%) of stigmaster…
Deoxycholic Acid Methyl Ester — a Novel Bacterial Metabolite of Cholic Acid
1985
Summary Methyl deoxycholate was identified as a novel bacterial metabolite of cholate, produced anaerobically by strains of most saccharolytic Bacteroides species ( B. distasonis, B. eggerthii, B. fragilis, B. incommunis, B. thetaiotaomicron, B. uniformis, B. variabilis, B. vulgatus , and unnamed species). It was also detected with a few strains of Eubacterium and Lactobacillus species. Among 2476 freshly isolated human fecal cultures the frequency of carboxyl group esterification was comparable with that of 7α-dehydroxylation (92 versus 102 cultures). Both activities were, however, lost for unknown reasons after serial transfers. Two of ten mixed fecal cultures tested esterified 3α,7α- or …
Stability and extraction of bioactive sulfur compounds from Allium genus processed by traditional and innovative technologies
2017
Abstract Since ancient times, species from the Allium genus have been used in both culinary and medicinal applications. The health promoting properties, with well documented “evidence-based” studies, were attributed to the genus’ high content of bioactive organosulfur compounds. For these reasons, the organosulfur compounds have attracted interest in both food and pharmaceutical industries to be used as additives or supplements. Therefore, improvement in the extraction and stability during processing and storage of these molecules is crucial. The presented review documents the effects of traditional and innovative processing techniques on the extraction and stability of organosulfur compoun…
Supercritical Algal Extracts: A Source of Biologically Active Compounds from Nature
2015
The paper discusses the potential applicability of the process of supercritical fluid extraction (SFE) in the production of algal extracts with the consideration of the process conditions and yields. State of the art in the research on solvent-free isolation of biologically active compounds from the biomass of algae was presented. Various aspects related with the properties of useful compounds found in cells of microalgae and macroalgae were discussed, including their potential applications as the natural components of plant protection products (biostimulants and bioregulators), dietary feed and food supplements, and pharmaceuticals. Analytical methods of determination of the natural compou…
Bacteria of the Genus Roseobacter Associated with the Toxic Dinoflagellate Prorocentrum lima
1998
The dinoflagellate Prorocentrum lima is known to produce diarrhetic shellfish poisons. However, it is yet unclear if the dinoflagellates themselves or the bacteria associated with them produce the toxins. Here we analyze the toxicity as well as the spectrum of bacteria in two cultures of P. lima, namely P. lima-SY and P. lima-ST, which initially derived from the same P. lima strain PL2V. Toxicity tests, applying the Artemia bioassay revealed in both cultures high levels of toxins. The bacteria, associated with the two cultures, were identified by PCR/nucleotide sequence analysis of the 16S rRNA gene. From cultures of P. lima-SY the dominant sequence was found to share a 93.7% similarity wit…
The helminth community of the wood mouse, <I>Apodemus sylvaticus</I>, in the Sierra Espuña, Murcia, Spain
2004
The helminth community of the wood mouse, Apodemus sylvaticus, in the Sierra Espuna was characterized after a complete analysis of its helminth community component and infracommunity structure relative to host age, sex and year of capture. The helminth community comprised 13 species: one trematode, four cestodes and eight nematodes. The cestode Pseudocatenotaenia matovi and the nematode Syphacia frederici were the most prevalent and abundant helminth species, respectively. Sixty four percent of mice analysed presented helminths with a direct cycle and 42% presented helminths with an indirect cycle. The helminth community presents a low diversity with infracommunities usually made up of only…
Arthropod-induced neoplastic formations on trees change photosynthetic pigment levels and oxidative enzyme activities
2005
Abstract In order to test the hypothesis that arthropod-induced neoplastic formations on trees affect biochemical characteristics of both the newly formed galls and host plant tissues, biochemical characteristics with a possible adaptive role were determined in nine gall-former–host tree combinations. Photosynthetic pigments, extractable protein content, and oxidative enzyme activities were determined in gall tissues, leaf tissues of galled leaves, and leaves on ungalled tree branches. Neoplastic tissues were characterized by a low content of photosynthetic pigments, decreased chlorophyll a/b ratio, lower extractable protein content, and decreased activities of peroxidase and polyphenol oxi…