486 research outputs found
Variational Multiscale Finite Element Method for Flows in Highly Porous Media
No full textWe present a two-scale finite element method (FEM) for solving Brinkman's and Darcy's equations. These systems of equations model fluid flows in highly porous and porous media, respectively. The method uses a recently proposed discontinuous Galerkin FEM for Stokes' equations by Wang and Ye and the concept of subgrid approximation developed by Arbogast for Darcy's equations. In order to reduce the "resonance error" and to ensure convergence to the global fine solution, the algorithm is put in the framework of alternating Schwarz iterations using subdomains around the coarse-grid boundaries. The discussed algorithms are implemented using the Deal.II finite element library and are tested on a number of model problems. © 2011 Society for Industrial and Applied Mathematics.Fraunhofer Institut fur Techno- und Wirtschaftsmathematik, Fraunhofer-Platz 1, 67663 Kaiserslautern, Germany, and Institute of Mathematics and Informatics, Bulgarian Academy of Sciences, Acad. G. Bonchev str., bl. 8, 1113, Sofia, Bulgaria ([email protected]). This author's research was supported by DFG project "Multiscale analysis of two-phase flow in porous media with complex heterogeneities."Department of Mathematics, Texas A&M University, College Station, TX 77843, and Institute of Mathematics and Informatics, Bulgarian Academy of Sciences, Acad. G. Bonchev str., bl. 8, 1113, Sofia, Bulgaria ([email protected]). This author's research was supported in parts by award KUS-C1-016-04 made by King Abdullah University of Science and Technology (KAUST) and by NSF grant DMS-1016525.Department of Mathematics, Texas A&M University, College Station, TX 77843 ([email protected]). This author's research was supported by DAAD-PPP D/07/10578, NSF grants DMS-0713829 and DMS-1016525, and the Studienstiftung des deutschen Volkes (German National Academic Foundation)
Phenolics from Brazilian propolis
No full textThe main phenolic constituents from Brazilian propolis, originating from Sao Paulo State, were isolated and identified: three flavonoids, a prenylated coumaric acid and two new benzopyranes, E and Z 2,2-dimethyl-6-carboxyethenyl-8-prenyl-2H-benzopyranes.Institute of Organic Chemistry Centre of Phytochemistry Bulgarian Academy of Sciences, Acad G. Bonchev str., 1113 SofiaDepto. Microbiologia e Imunologia Instituto de Biociencias UNESP, 18618-000 Botucatu/SPDepto. Microbiologia e Imunologia Instituto de Biociencias UNESP, 18618-000 Botucatu/S
Phenol Biodegradation by Two Xenobiotics-Tolerant Bacteria Immobilized in Polyethylene Oxide Cryogels
No full textBiofilms were formed on poly(ethylene oxide) (PEO) cryogels by using bacteria cultured from xenobiotics polluted environments and their phenol biodegrading capability was studied. PEO cryogels were synthesized via UV irradiation cross linking of moderately frozen aqueous system. Two xenobiotics tolerant bacterial isolates KCM R5 and KCM RG5 were used to construct the biofilms on the cryogels.
Obtained PEO-biofilms were assessed for their ability to remove phenol at concentrations 300, 400, 600 and 1000 mg L-1 for 28 days. The biofilm PEO-KCM RG5 removed phenol up to 600mg L-1/24 h, whereas the biofilm PEO-KCM R5 was able to degrade up to 1000 mg L-1/24 h. The high content of free-water in the cryogels allowed reproduction of the used bacteria. The high content of free-water in the cryogels allowed reproduction of the used bacteria. Short initial adaptation of the PEO-bio�lms with 100 mg L-1/24 h phenol was crucial for protecting the bacterial cells from dead. The obtained results showed that the liquid debit through the bio�lms on the 28th day of the experiments was lower than at the beginning. The cryogels demonstrated non-toxicity, high biocompatibility with bacteria and excellent mechanical characteristics. After aggressive phenol treatment the PEO-biofilms remained compact, porous and
elastic. The investigated new biological materials demonstrate potential for application in the industrial wastewater treatment technologies
Effect of semen extenders on sperm motion of in vitro stored muscovy drake spermatozoa
No full textA study for the influence of semen extenders IMV-buffer, HIA- 1 and AU on
sperm motion characteristics of Muscovy drake spermatozoa was carried out.
The semen from each male (n=6) was divided into three equal parts and diluted
in ratio 1:3 (semen:extender) with the IMV-buffer, HIA-1 and AU respectively,
and then was stored at temperature 0-4C? for 6 hours. Sperm motion parameters
- velocity of spermatozoa (rapid, medium, slow and statistic), VCL, VSL, VAP,
LIN, STR, WOB were measured using a Sperm Class Analizer (Micropticum,
Spain). Computer-assisted sperm motion analysis indicated that Muscovy
spermatozoa preserved a rapid and medium sperm velocity after 6 hours in
vitro storage in three examination extenders. The total VCL, VSL and VAP of
spermatozoa in the semen diluted with AU extender were 110.47?7.44 ?m/s,
29.42?2.02 ?m/s and 57.39?3.73 ?m/s, in the semen diluted with IMV-buffer
were 94.93?11.10 ?m/s, 27.57?2.45 ?m/s and 51.35?4.98 ?m/s, and in the semen
diluted with HIA-1 were 68.48?12.74 ?m/s, 20.08?4.18 ?m/s and 37.75?7.65
?m/s, as the differences were significant between AU and HIA-1 - (P<0.05).
About LIN, STR, WOB there were no significant differences for the influence
of the extenders.</jats:p
Georgi Bonchev's paper "Contribution to the springs in Bulgaria", 1939, and its significance for hydrogeology in Bulgaria
No full textIn 1939, one of the first summarizing works of the famous Bulgarian geologist Georgi Bonchev “Contribution to the springs in Bulgaria” related to groundwater in the country was published. In his field research, the author visited and described about 60 natural springs or groups of springs with temperatures from 20 °C to over 75 °C, attached to different tectonic zones, over 40 lukewarm and cold springs with mineralized waters and about 290 karst and other cold springs. This article is also relevant for modern hydrogeology. The presented general picture of the locations of the springs, the discharge and qualities of the waters from the natural springs before 1939 allows making comparisons of the occurred changes due to natural and anthropogenic factors
On the Wiener Number of Thorn Trees, Stars, Rings, and Rods
No full textThe concept of thorn graphs proposed recently by Gutman is extended to the broader concept of generalized thorny graphs. The latter preserve unchanged certain parts of the parent graph while applying the procedure of thorn graph generation to the rest of the graph. Thorn stars and rods are typical examples of such generalized thorn graphs, owing to the unchanged star center, and the other-than-terminal rod vertices. Formulae are presented for the Wiener number of these and other classes of (generalized) thorn graphs
Application of the mössbauer effect to microgram samples with resonance sample scintillators
No full textA COMPARATIVE ANALYSIS BETWEEN TWO TYPES OF DATA PROCESSING OBTAINED THROUGH UAV FROM A ORGANICAL FIELD WITH EINKORN (TRITICUM MONOCOCCUM L.)
No full textThe aim of the present study is to determine which type of data processing obtained from an unmanned aerial vehicle (UAV) is more suitable for predicting the yields of the eikorn crop grown under organic farming conditions. The comparison is made between data obtained from the UAV at the pixel level of 7 × 7 cm and when aggregating the pixels to a pixel size of 1 × 1 m. The experiment was conducted during the agricultural year 2020–2021 on a certified organic field located in the municipality of Parvomai, Plovdiv region
Unravelling Landscape Permanencies: A Digital Historical Journey into the Milanese Countryside
No full textThe objective of the applied research is the construction of a cross-media map to discover the agricultural landscape, through the digitization and geo-referencing on Google maps of historical maps and photos of the Ca Granda Foundation Archive. It allows the visualization and immediate accessibility of landscape transformations, in a sort of multimedia journey through time
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