Romanian policy makers have to perceive that human intervention on river basins land cover is influencing rainfall-runoff relation and the used methodology cannot accurately estimate watershed surface flow transformations. Global water cycles and energy fluxes understanding is leading to better predictions of land atmosphere interaction and local hydro-climates evolution. The water transfer time determination from rainfall to runoff needs accurate measurements of river basins hydrological parameters. Here, we analyzed and compared the lag time value results of two different methodologies (curve number and rational methodology) used for 54 Romanian small catchment areas study. The focus of this paper is the lag time evaluation and interpretation for an effective implementation of the best methodology approach in the Romanian geographical space. Our research in small river basins was developed using remote sensing technology maps, GIS and environmental datasets in combination with field work on every drainage basin in order to assess the specific morphological features and validate the land cover typology. We found that Soil Conservation Service - Curve Number (SCS-CN) method is widely used according to USA landscape features classification, but not necessarily applicable to Romanian river basins characteristics. Our results show how the official Romanian rational methodology national standard (RNS) can be improved and the limits of SCS-CN method.
Ozonation is an innovative way to preserve high quality of seed during storage and it is an alternative to harmful organophosphorus agents. Disclosure of changes in the rapeseed oil under the influence of oxidative action of ozone on the seeds was the aim of the work and is presented for the first time. Two ozone concentrations and different length of ozonation were applied. The changes in tocopherols, phenolics, flavonoids contents, antiradical activity and oxidative stability were examined. The average vitamin E concentration was 33 mg per 100 g of oil before and 31.7 after ozonation of seeds. The average content of phenolic compounds was 14.3 mg of sinapic acid g−1 and 16.9 after the ozone treatment. Changes in the flavonoids content and antioxidant activity were observed too. Ozonation caused a decrease in the vitamin E concentration which resulted also in reducing the quenching of free radicals and reduction of oil induction time. 相似文献
Fire Technology - Natural materials like wood are increasingly used in the construction industry, making the understanding of their ignition and burning behaviour in fires crucial. The state of the... 相似文献
In this study, two techniques, namely electrospinning and needle-punching processes, were used to fabricate bioactive polycaprolactone/hydroxyapatite scaffolds with a final bilayer nano-/micro-fibrous porous structure. A hybrid scaffold was fabricated to combine the beneficial properties of nanofibers and microfibers and to create a three-dimensional porous structure (which is usually very difficult to produce using electrospinning technology only). The first part of this work focused on determining the conditions necessary to fabricate nano- and micro-fibrous components of scaffold layers. A characterization of scaffold components, with respect to their morphology, fiber diameter, pore size, wettability, chemical composition and mechanical properties, was performed. Then, the same process parameters were applied to produce a hybrid bilayer scaffold by electrospinning the nanofibers directly onto the micro-fibrous nonwovens obtained in a traditional mechanical needle-punching process. In the second part, the bioactive character of a hybrid nano-/micro-fibrous scaffold in simulated body fluid (SBF) was assessed. Spherical calcium phosphate was precipitated onto the nano-/micro-fibrous scaffold surface proving its bioactivity. 相似文献
The present in vivo study determined the microbiological counts of the gingival crevicular fluid (GCF) among patients with fixed dental prostheses fabricated using three different techniques. A total of 129 subjects were divided into three study groups: first, cobalt-chrome-based, metal-ceramic prostheses fabricated by the conventional method (MC, n = 35); the second group consisted of cobalt-chrome-based, metal-ceramic prostheses fabricated by the computer-aided design and computer-aided manufacturing (CAD/CAM) technique (CC-MC, n = 35); the third group comprised zirconia-based ceramic prostheses fabricated using the CAD/CAM technique (CC-Zr, n = 35). The control consisted of 24 patients using prostheses fabricated with either MC, CC-MC, or CC-Zr. The GCF was obtained from the subjects before treatment, and 6 and 12 months after the prosthetic treatment. Bacteriological and bacterioscopic analysis of the GCF was performed to analyze the patients’ GCF. The data were analyzed using SPSS V20 (IBM Company, Chicago, IL, USA). The number of microorganisms of the gingival crevicular fluid in all groups at 12 months of prosthetic treatment reduced dramatically compared with the data obtained before prosthetic treatment. Inflammatory processes in the periodontium occurred slowly in the case of zirconium oxide-based ceramic constructions due to their biocompatibility with the mucous membranes and tissues of the oral cavity as well as a reduced risk of dental biofilm formation. This should be considered by dentists and prosthodontists when choosing restoration materials for subjects with periodontal pathology. 相似文献
The o-anisidine and pyrrole have been polymerized by the electrochemical oxidation of monomers on gold electrodes, covered with self-assembled monolayers. The obtained polymer–monolayer systems have been investigated by cyclic voltammetry in aqueous supporting electrolyte solutions containing K4Fe(CN)6 and Ru(NH3)6Cl3. The deposition of conducting polymers strongly depends on the integrity of a monolayer. In the case of a large number of SAM defects, the polymerization of o-anisidine and pyrrole leads to the formation of nuclei of the conducting polymer in the insulating matrix of the thiol monolayer. When the polymer is in the conducting (oxidized) form, the nuclei act as an array of microelectrodes. The polarogram-shaped voltammograms obtained for K4Fe(CN)6 confirm the hemispherical diffusion of redox species to the polymer nuclei. When the polymer is in the non-conducting (reduced) form, the polymer–octadecanethiol layer blocks the redox processes on the electrode. The exponential-type CV curves observed for Ru(NH3)6Cl3, when the polymer is in its non-conducting state, can be assigned to the tunnelling of electrons through the passivating layer. The use of monolayers with a low number of defects influences the mechanism of polymer growth. Thus, the polypyrrole grows on the layer of thiols, and the poly(o-anisidine) forms polymer nuclei. 相似文献
The application of 1,9-nonanedithiol (NDT) self-assembled monolayer (SAM) on gold for the electrochemical determination of Cd2+ was studied. Interestingly, we found that a NDT SAM strongly affects the stripping wave of Cd, resulting in a sharp peak that was used for electroanalytical determination of Cd2+ in aqueous solutions. The different parameters, such as potential and time of deposition of Cd, were examined. Furthermore, polarization-modulated infrared reflection absorption spectroscopy (PM IRRAS) and X-ray photoelectron spectroscopy (XPS) were used for exploring the interaction between the deposited Cd and the thiol groups on Au. FTIR measurements clearly indicate that NDT is assembled in a disordered liquid type monolayer interacting with the Au electrode via both thiol moieties. XPS reveals that Cd is stripped at two different potentials and that the signal of sulfur is almost unchanged by deposition and desorption of Cd. All these finding allude to the interesting conclusion that Cd is deposited on Au lifting to some extent the thiol groups. 相似文献