Papers by Keyword: Mineralization

Abstract: Self-assembly and mineralization of type I collagen (Col) with nanocrystalline apatite (nAp), by adding a solution of Ca(OH)₂ to a stirred Col-H₃PO₄ solution by fast dripping, allowed the preparation of Col/nAp fibrils with good crystallographic control of the mineral phase. In this work, in addition, we have cross-linked the mineralized fibers by using different reagents, namely glutaraldehyde (GTA), tannic acid (TA), 1-Ethyl-3-(3-dimethyl aminopropyl)-carbodiimide combined with N-Hydroxysuccinimide (EDC/NHS), and genipin (GP), aimed at producing different types of biopolymeric Col/nAp-based drug delivery scaffolds. In parallel, we have investigated two different methods to impregnate the scaffolds with molecules of the cocrystal diclofenac-metformin (DF-MET). The result, when using TA as a crosslinking reagent, shows the sequence of mineralized fibrils impregnation followed by crosslinking leads to maximum cocrystal molecule loading. The impregnated material is expected to be useful in settings with excessive and prolonged inflammation, since they affect negatively the fracture healing/bone repair processes, especially during the early stages of healing.

Abstract: The analysis of the water-salt balance data in the Bolshoi Tambukan lake within the period 1972-2015 is performed. The regression equation of the therapeutic mud concentration mineralization correlation in the lake with water volume is received. The tendency of minerals concentration reduction in the lake for the last years has been revealed.

Abstract: In this study, PCL electrospun fibers were deposited on the Ti-30Ta alloy for change the surface properties. Experimental Ti-30Ta alloy was obtained by melting titanium and tantalum in arc melting furnace with argon atmosphere. Ingots were homogenized and bars with 10 mm of diameter were obtained in rotative swagging. PCL fibers were deposited on disks of the alloy by electrospinning. Plasma treatment was carried out for change PCL electrospun superficial energy by using stainless steel plasma reactor. Samples were immersed in mineralization solution for apatite growth. Surfaces were evaluated by using SEM, X-rays diffraction and contact angle. Samples exhibited hydrophilic behavior after plasma treatment and mineralization. Results are very interesting for biomedical applications.

Abstract: The issue of natural fibers used for the production of materials with thermal insulation properties is its high moisture sensitivity and susceptibility to biodedgradaci. Effective protection of these fibers may be for some applications so. Mineralization which involves the application of inorganic compounds / binder to the surface of natural fibers. The paper focuses primarily on ways of implementing the mineralization using inorganic binders, and then changes the properties of natural fibers after application of various types of inorganic binders.

Abstract: A sequential ultrasound intensified photocatalytic reactors was investigated to degrade and mineralize typical endocrine disruptor, bisphenol A (BPA) using nanometer TiO₂ as photocatalyst. The process parameters i.e., US power, TiO₂ dosages, air flow rate and circulating liquid velocity of the reactors were optimized of the process. Under the optimum operation condition, nearly 90% and 80% BPA was degraded and mineralized in the reactor within 2.5 h. The combination of sonolysis and photocatalysis of TiO₂ exhibits a synergetic effect, and benefits for BPA mineralization.

Abstract: The paper describes use of hemp boon as a natural organic filler for building materials, especially concrete designed as heat - insulating filler material around the load-bearing structure of wooden buildings. In constructions, hemp has been used in the form of mats made of hemp fiber, with the addition of bonding bicomponent fibers and soda solution for protection against burning and rots. Mats are formed by pneumatic fleece, they are subsequently thermally treated and then cut to the desired dimensions. Calcium-hemp building material is a revolutionary construction and thermal insulating material which can be used for building the entire building, bricks or other insulation are not necessary. The trend is spreading across Europe from France, where the mixture of boon and lime was used in the 16^th and 17^th centuries for the construction of timber-framed houses. Although there are hundreds of buildings made from hempcrete in Europe, its use in our country develops very slowly. Concrete is a mixture of hemp boon, lime hydrate, cement and water. It is a recyclable material that offers high thermal and sound insulation. The biggest advantage is undoubtedly the speed of construction, namely hemp concrete hardens very quickly.

Abstract: The aim of this work was to evaluate the effects of different coagulation-flocculation conditions on the levels of natural organic matter removal for several mineralized water types in Algeria. First, trials are carried out on solutions prepared by dissolving humic acid in media with various degree of mineralization (distilled water and mineralized Algerian groundwater), using aluminium sulphate as coagulant. The effectiveness of the coagulation process appeared to depend not only on the pH of coagulation and coagulant dosages, but also inorganic constituents in water. Results showed obviously a stoechiometric relationship between the initial concentration of humic substances and optimal coagulant dosages for each water sample. Improvement of process performance is also investigated by using local clay as coagulant aid in coagulation-flocculation step. The use of bentonitic clay as a coagulant aid for alum improved the humic acid removal efficiency to some extent, especially when clay is added durind slow mix step. The experimental results of this study demonstrate the feasibility of removing humic substances from two surface waters using a flocculation-adsorption process.

Abstract: Vacuum distillation (VD) by NaOH was used for treatment of petroleum refinery wastewater, and the optimal experimental conditions including operation vacuum degree, initial pH, feeding process were also investigated. Chemical oxygen demand (COD), conductivity and pH value were utilized to estimate the removal efficiency for treatment of refinery wastewater. Based on experimental results, it can be concluded that NaOH displays higher efficiency for the treatment of refinery wastewater, the pellucid effluents with satisfied COD removal efficiency (99%) and low salinity were obtained in fully batch process at operation vacuum degree of-0.085 MPa, operation time of 50 min, initial pH of 11, and the corresponding pH values of effluents varied from 7 to 9. Thus, in view of fine COD and mineralization removal efficiency, the VD technology is an effective approach to treat petroleum refinery wastewater.

Abstract: Saidu gold deposit, located in back arc basin at south margin of the west Altay Mountain, is orogenic gold deposit. It is strictively controlled by ductile-shear zone, occurring in altered mylonite zone of Mar-kakol giant belt. The δ³⁴S values of pyrite in the gold deposit range from 3.53‰ to 5.88‰; the lead isotopic compositions are fairly constant, with ²⁰⁶Pb/²⁰⁴Pb ranging from 18.010 to 18.359, ²⁰⁷Pb/²⁰⁴Pb ranging from 15.488 to 15.579, and ²⁰⁸Pb/²⁰⁴Pb ranging from 38.1116 to 38.3551. Sulfur and lead isotope studies indicated that ore-forming materials originated from the deep portion, and had close relationship with magmatic activity. The ore materials were obtained from rocks of the lower crust during the orogenic period; the main gold mineralization should have relations with tectonic extention settings of post-collision orogenic.

Abstract: Silk fibroin/sodium alginate blend films and its hydroxyapatite deposition were prepared and characterized by scanning electron microscopy, wide angle X-ray diffraction, Fourier transform infrared analysis, and thermal analysis. The surface of blend films showed much more rod-like structure dispersing uniformity and its average length increasing from 181 to 803nm with increasing the contents of sodium alginate. The crystal structure of silk fibroin and the compatibility of the two components were associated with the content of sodium alginate in silk fibroin/sodium alginate blend films. The silk I and silk II crystal structures of silk fibroin were co-existed in the blend films and a rather complex conformation transition occurred, which was confirmed by wide angle X-ray diffraction and Fourier transform infrared analysis. Thermal behavior of blend films was interrupted by adding different contents of sodium alginate. Adding 30.0% sodium alginate or more, the endothermic peak of moisture evaporation shifted downward from 111 to 80°C, and the degradation peaks at 243 and 279°C, respectively, indicating an obviously two phase structure in the blend films. In addition, the rod-like HAp crystals were grown on the surface of blend films. This result may provide some new ideas in the design and fabrication of new materials through the silk fibroin/sodium alginate composite materials template for the hydroxyapatite crystal growth.