Search results for "solution"
showing 10 items of 5638 documents
Jute bioblanket as a soil rehabilitation strategy in Sorocaba, Brazil: Soil chemistry and SWOT approaches
2019
Made available in DSpace on 2022-04-29T08:28:27Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-09-01 Soil erosion and the invasion of exotic plant species are major constraints to achieve sustainable development around the world. Currently, we find few products devoted concomitantly to combatting soil erosion as well as the establishment of unwanted exotic plants. In this paper, we introduce a new product, called herein a bioblanket, that protects the soil and impedes the establishment of exotic plant species. This product is of simple design, and to manufacture it, we use two biodegradable materials: jute tissue and grass wastes. We designed this product to combat soil erosion and …
Dynamics of hyaluronan aqueous solutions as assessed by fast field cycling NMR relaxometry.
2010
Fast field cycling (FFC) NMR relaxometry has been used to study the conformational properties of aqueous solutions of hyaluronan (HYA) at three concentrations in the range 10 to 25 mg mL(-1). Results revealed that, irrespective of the solution concentration, three different hydration layers surround hyaluronan. The inner layer consists of water molecules strongly retained in the proximity of the HYA surface. Because of their strong interactions with HYA, water molecules in this inner hydration layer are subject to very slow dynamics and have the largest correlation times. The other two hydration layers are made of water molecules which are located progressively further from the HYA surface.…
Phases transitions in complexe oxides with perovskite structure : case system (1-x)Na0,5Bi0,5TiO3 - xCaTiO3
2015
The solid solutions (1-x)Na0,5Bi0,5TiO3 (NBT) – xCaTiO3 (CT) were studied by X-ray diffraction, Raman spectroscopy, scanning electron microscopy, impedance spectroscopy and DSC. These materials have a perovskite crystalline structure. This study reveals not only the complexity but also the richness of physical phenomena in these compounds: phases transitions sequences, the Ca2+ effect on the physical-chemistry properties and the relation between dielectric properties and crystalline structure. Thereby, (1-x)NBT – xCT solid solutions (0 ≤ x ≤ 1.00) were synthesized by chemical solid route, then they were sintered by a particular procedure in order to avoid sodium and bismuth volatilization. …
Digital orthophotos at a scale of 1:5000 from high resolution satellite images
2004
This paper describes the first results of a study, carried out within the national research program “Cofin2001”, on the potential use of high resolution satellite images for making digital orthophotos at a scale of 1:5000 and 1:10,000. Particularly, images from IKONOS II and QuickBird of four different types of areas were employed: the first area is the city of Palermo, a greatly urbanized area; the second area is the extra-urban territory near the town of Contessa Entellina in south-western Sicily; the third area is the famous tourist resort of Scopello, in the western Sicily; the last area is the Caselle Airport, a flat zone near Torino. The first three images were orthorectified by using…
Ab initio modelling of oxygen vacancies and protonic defects in La1−xSrxFeO3−δ perovskite solid solutions
2016
Using hybrid density functionals, detailed ab initio calculations were performed for oxygen vacancies and protons in La1−xSrxFeO3−δ perovskite solid solutions which may serve as a cathode material in protonic ceramic fuel cells. The atomic and electronic structures of different configurations of defects and the role of Fe oxidation state are analyzed in detail. The energetics of the reduction and hydration reactions are investigated. The hydration energy is found to be significantly smaller than for Ba(Zr1−xYx)O3−x/2 electrolyte materials, and the role of basicity as one decisive factor is discussed.
Green infrastructures for the energetic and environmental sustainability of cities
2019
The inexorable extension of urbanization is consuming huge amounts of soil drastically reducing natural vegetation, replacing it with buildings and low albedo surfaces. The changes due to the different thermal properties of surface materials and the lack of evapotranspiration in urban areas lead to a phenomenon known as "urban heat island effect". By reintroducing the vegetation back into the urban landscape, a partnership between nature and cities should be strengthened to create a new sustainable urban environment. Since the outer surfaces of building offer a great amount of space for vegetation, planting on roofs and walls has become one of the most innovative way to provide several envi…
Application of reverse electrodialysis to site-specific types of saline solutions: A techno-economic assessment
2019
Abstract Salinity gradients are a non-conventional source of renewable energy based on the recovery of the Gibbs free energy related to the mixing of solutions at different concentrations. Reverse Electrodialysis is a promising and innovative technology able to convert this energy directly into electric current. The worldwide availability of salinity gradients is limited to those locations where water bodies at different salinity levels are present. The present work analyses a number of different scenarios worldwide, in locations where salinity gradients are naturally available or generated by anthropogenic activities. A techno-economic model of the Reverse Electrodialysis process is presen…
Renormalized solutions for degenerate elliptic–parabolic problems with nonlinear dynamical boundary conditions and L1-data
2008
Abstract We consider a degenerate elliptic–parabolic problem with nonlinear dynamical boundary conditions. Assuming L 1 -data, we prove existence and uniqueness in the framework of renormalized solutions. Particular instances of this problem appear in various phenomena with changes of phase like multiphase Stefan problems and in the weak formulation of the mathematical model of the so-called Hele–Shaw problem. Also, the problem with non-homogeneous Neumann boundary condition is included.
An effective negative pressure cavitation-microwave assisted extraction for determination of phenolic compounds in P. calliantha H. Andr.
2013
A novel negative pressure and microwave assisted extraction technique (NMAE) was first proposed and applied for extraction of phenolic compounds from pyrola. [C₄MIM]BF₄ aqueous solution was selected as extraction solvent. Optimal extraction conditions were microwave power 700 W, negative pressure -0.07 MPa, temperature 40 °C, liquid-solid ratio 20 : 1, ionic liquid (IL) concentration 0.5 M, extraction time 15 min. The predominance of NMAE was investigated by comparing with microwave-assisted extraction (MAE) and negative pressure cavitation extraction (NPCE) using a first-order kinetics equation. The C∞ values of the target compounds by NMAE were from 0.406 to 5.977 mg g⁻¹ higher than these…
Reproducibility and accuracy in the morphometric and mechanical quantification of trabecular bone from 3Tesla magnetic resonance images
2014
Abstract Objective We used an animal model to analyze the reproducibility and accuracy of certain biomarkers of bone image quality in comparison to a gold standard of computed microtomography (μCT). Materials and methods We used magnetic resonance (MR) imaging and μCT to study the metaphyses of 5 sheep tibiae. The MR images (3 T) were acquired with a T1-weighted gradient echo sequence and an isotropic spatial resolution of 180 μm. The μCT images were acquired using a scanner with a spatial resolution of 7.5 μm isotropic voxels. In the preparation of the images, we applied equalization, interpolation, and thresholding algorithms. In the quantitative analysis, we calculated the percentage of …