Search results for "WELL"
showing 10 items of 2241 documents
The Relevance of Kneading and Extrusion Parameters in the Manufacture of Active Porous Aluminas from Pseudoboehmites
1987
In order to study the effect-on crushing strength, attrition resistance, specific pore volume, and pore volume distribution of extrudates-of kneading and extrusion parameters in the manufacture of active porous aluminas, a commercial pseudoboehmite (Pural SB from Condea Chemie, Brunsbuttel, FRG) was employed. A minimum kneading torque was required to prepare an extrudable paste, predetermined by extrusion conditions. The torque had an upper limit with respect to certain extrudate properties. The amount of water and the concentration of nitric acid as binder solutions were found to have a decisive bearing on the mechanical properties and the distribution of the pore volume. Crushing strength…
A bending theory of thermoelastic diffusion plates based on Green-Naghdi theory
2017
Abstract This article is concerned with bending plate theory for thermoelastic diffusion materials under Green-Naghdi theory. First, we present the basic equations which characterize the bending of thin thermoelastic diffusion plates for type II and III models. The theory allows for the effect of transverse shear deformation without any shear correction factor, and permits the propagation of waves at a finite speed without energy dissipation for type II model and with energy dissipation for type III model. By the semigroup theory of linear operators, we prove the well-posedness of the both models and the asymptotic behavior of the solutions of type III model. For unbounded plate of type III…
Design, characterization and in vitro evaluation of 5-aminosalicylic acid loaded N-succinyl-chitosan microparticles for colon specific delivery
2011
The objective of this study was to prepare NS-chitosan microparticles for the delivery of 5-aminosalicylic acid (5-ASA) to the colon. Microparticles can spread out over a large area of colon allowing a more effective local efficacy of 5-ASA. N-Succinyl-chitosan was chosen as carrier system because of its excellent pharmaceutical properties in colon drug targeting such as poor solubility in acid environment, biocompatibility, mucoadhesive properties, and low toxicity. It was prepared by introducing succinic group into chitosan N-terminals of the glucosamine units. 5-ASA loaded NS-chitosan microparticles were prepared using spray-drying. As a control, a matrix obtained by freeze-drying techni…
New gellan gum-graft-poly(D,L-lactide-co-glycolide) copolymers as promising bioinks: Synthesis and characterization
2020
This research focused on the aim of tackling the urgent demand of printable biomaterials, hence we synthetized and characterized three gellan gum-graft-poly(d,l-lactide-co-glycolide) copolymers (GGm-PLGA a, b and c) which differed in the graft substitution degree. We investigated the effect of the polyester chain grafted onto hydrophilic backbone of gellan gum in terms of physicochemical properties and the ability of the system to print 3D cell laden constructs. In particular, we evaluated thermo-rheological, ionotropic crosslinking, shear thinning, swelling and stability properties of these copolymers and their derived biomaterials and findings related to the degree of functionalization. M…
On the distribution and subspecific variation of the Tunisian- Algerian endemicDelphinium sylvaticum(Ranunculaceae)
2015
The morphology and biogeography of the Tunisian–Algerian endemic Delphinium sylvaticum Pomel has been studied in Tunisia. As presented here, this study resulted in an enlargement of the known distribution and in the description of two new subspecies: D. sylvaticum subsp. ichkeulianum El Mokni, Domina, Sebei & El Aouni and D. sylvaticum subsp. purpureum El Mokni, Domina, Sebei & El Aouni native to Tunisia in Mogods and in the northeast regions, respectively. Besides ecological features and clearly separated distribution, the two new subspecies show very well differentiated morphology. An updated distribution map and a diagnostic key of the studied taxa are provided.
Global variability in seawater Mg:Ca and Sr:Ca ratios in the modern ocean
2020
12 pages, 5 figures, supporting information https://doi.org/10.1073/pnas.1918943117.-- Data Availability. Our published databases are publicly accessible for readers, and they are deposited at the NOAA NCEI at https://data.nodc.noaa.gov/cgi-bin/iso?id=gov.noaa.nodc:0171017.-- Correction for Lebrato et al., Global variability in seawater Mg:Ca and Sr:Ca ratios in the modern ocean; Proceedings of the National Academy of Sciences of the USA 118(49): e2119099118 (2021); doi: 10.1073/pnas.2119099118; http://hdl.handle.net/10261/258054.-- This is Pacific Marine Environmental Laboratory contribution number 5046
Factors controlling plankton productivity, particulate matter stoichiometry, and export fluxin the coastal upwelling system off Peru
2020
Abstract. Eastern boundary upwelling systems (EBUS) are among the most productive marine ecosystems on Earth. The high productivity in surface waters is facilitated by upwelling of nutrient-rich deep waters, with high light availability enabling fast phytoplankton growth and nutrient utilization. However, there are numerous biotic and abiotic factors modifying productivity and biogeochemical processes. Determining these factors is important because EBUS are considered hotspots of climate change, and reliable predictions on their future functioning requires understanding of the mechanisms driving biogeochemical cycles therein. In this study, we used in situ mesocosms to obtain mechanistic un…
Guided Optical Waves in a Ferroelectric Liquid Crystal Layer: A Birefringence Analysis of Molecular Orientation on the Switching Process
1995
Abstract Guided optical waves are very sensitive to the alteration of optical properties of dielectric media. In this report, we demonstrate the use of guided waves for studying dynamic behavior of ferroelectric liquid crystals. Propagating light in the anisotropic medium suffers a birefringent effect, which causes coupling of p- and s-polarized light. Theoretical calculations, based on the Maxwell equations, successfully describe this phenomena, using a dielectric tensor diagonal in molecular coordinates, which is transformed to the laboratory coordinate system by three Euler angles. The waveguide measurements are able to probe the molecular orientation and movement of the liquid crystal m…
Innovacions amb blogs: desenvolupament de competències del futur mestre i benestar subjectiu docent
2012
Es descriuen tres experiències innovadores del Grau de Maestro amb blogs, orientades al desenvolupament de competències específiques i transversals: un blog de ressenyes literàries infantils; una revista digital com a espai per a la investigació i el treball col·laboratiu; i un i-portafolio per visibilizar pràctiques, avaluar progressos en l'aprenentatge i desenvolupar tutories. Es va constatar en totes elles una alta participació, motivació i implicació, i el desenvolupament de competències d'ordre superior, com les habilitats comunicatives, digitals, d'anàlisis i síntesis…. Amb això, el professorat va experimentar un alt grau de benestar subjectiu, vinculat amb la seva satisfacció en rela…
Serum Dehydroepiandrosterone Sulfate and Risk for Type 2 Diabetes in Older Men and Women: The Pro.V.A Study
2016
Objective: A large body of clinical data suggests the importance of endogenous sex hormones in the pathogenesis of diabetes, but very little is known about the possible relationship between dehydroepiandrosterone sulfate (DHEAS) and diabetes, particularly in the elderly. We aimed, therefore, to examine whether high serum levels of DHEAS have any protective effects on the incidence of type 2 diabetes and to elucidate the possible role of gender in a cohort of older subjects. Methods: We followed 1258 community-dwelling subjects aged ≥65 years without type 2 diabetes who belonged to the Progetto Veneto Anziani (Pro.V.A.) for 4.4±1.2 years. DHEAS were measured at baseline and categorized into …