Summary An integrated process for producing liquid fuels from synthesis gas via a two-stage Fischer-Tropsch (FT) reaction is disclosed. An iron catalyst was used in the first bed of a fixed-bed reactor
followed by a ruthenium promoted cobalt catalyst in the second bed. The activity and selectivity of the dual-bed system were
assessed and compared with those using catalysts in a single bed system, separately. The methane selectivity in the dual-bed
reactor was about 11% less compared to that of the single-bed system. The C5+ selectivity for the dual-bed reactor was 19.7% higher than that of the single-bed system. 相似文献
Hydroquinone (HQ) loaded polymer solution was electrospun for its topical application. Nanofibers were then investigated in terms of stability, drug release, and antifungal activity. The effect of chitosan (CS) was investigated on the viscosity, stability, drug release, and antifungal activity of the developed formulation. Results indicate a significantly stable HQ-loaded nanofiber formulation. The addition of CS caused hydration of the drug delivery system and enhanced drug release but reduced its stability. HQ-loaded nanofiber mat showed significant antifungal activity, however, there was no inhibition zone in samples containing CS. 相似文献
A mathematical formulation for the contact of rough surfaces is presented. The derivation of the contact model is facilitated through the definition of plastic asperities that are assumed to be embedded at a critical depth within the actual surface asperities. The surface asperities are assumed to deform elastically whereas the plastic asperities experience only plastic deformation. The deformation of plastic asperities is made to obey the law of conservation of volume. It is believed that the proposed model is advantageous since (a) it provides a more accurate account of elastic-plastic behavior of surfaces in contact and (b) it is applicable to model formulations that involve asperity shoulder-to-shoulder contact. Comparison of numerical results for estimating true contact area and contact force using the proposed model and the earlier methods suggest that the proposed approach provides a more realistic prediction of elastic-plastic contact behavior. 相似文献
Journal of Thermal Analysis and Calorimetry - In the current study, computational fluid dynamics code was used to perform 3D simulation of mixture formation and combustion of biodiesel fuel spray... 相似文献
The preparation of pyrazolo pyrimidinone derivatives was performed by using five component reactions of phthalaldehyde, cyanomethylamine, electron deficient acetylenic compounds, isocyanate, hydrazine, and catalytic amounts of ZnO/Fe3O4-magnetic nanoparticles as a high performance catalyst under ultrasonic conditions at ambient temperature in aquause media at room temperature. It should be mentioned that this catalyst was prepared using Spinacia oleracea water extract. In addition, for investigation of antioxidant ability, radical trapping by DPPH and reducing power of ferric ion experiments was performed. As a result, synthesized compounds show excellent radical trapping by DPPH and good reducing ability of ferric ion. The current procedure has the benefits for instance excellent yield of reaction, green media, and easy separation of product and catalyst. 相似文献
In this work, a triblock copolymer polytetrahydrofuran–block-poly(glycidyl azide)–block-polytetrahydrofuran was synthesized through ring-opening polymerization of epichlorohydrin and tetrahydrofuran catalyzed by BF3-diethyl ether at 30°C, and further modification. The structure of the polymer was verified by IR, 1H and 13C NMR spectroscopy. The decomposition and kinetic parameters of the block copolymer such as its activation energy and frequency factor were determined using the differential scanning calorimetry and thermo-gravimetric analysis. The results revealed that the main thermal degradation for the copolymer occurs in the temperature range of 220–250°C. Finally, the effect of polytetrahydrofuran content on the thermal stability and decomposition temperature of the overall copolymer was investigated. 相似文献
Gelatin nanoparticles can be tuned with respect to their drug loading efficiency, degradation rate, and release kinetics, which renders these drug carriers highly suitable for a wide variety of biomedical applications. The ease of functionalization has rendered gelatin an interesting candidate material to introduce specific motifs for selective targeting to specific organs, but gelatin nanoparticles have not yet been modified to increase their affinity to mineralized tissue. By means of conjugating bone‐targeting alendronate to biocompatible gelatin nanoparticles, a simple method is developed for the preparation of gelatin nanoparticles which exhibit strong affinity to mineralized surfaces. It has been shown that the degree of alendronate functionalization can be tuned by controlling the glutaraldehyde crosslinking density, the molar ratio between alendronate and glutaraldehyde, as well as the pH of the conjugation reaction. Moreover, it has been shown that the affinity of gelatin nanoparticles to calcium phosphate increases considerably upon functionalization with alendronate. In summary, gelatin nanoparticles have been developed, which exhibit great potential for use in bone‐specific drug delivery and regenerative medicine.
Titanium dioxide (i.e. TiO2) in nano-form is a constituent of many nanomaterials that are used in sunscreens, cosmetics, industrial products and in biomedical applications. Quantification of TiO2 nanoparticles in various matrixes is a topic of great interest for researchers studying the potential health and environmental impacts of nanoparticles. However, analysis of TiO2 as Ti4+ is difficult because current digestion techniques require use of strong acids that may be a health and safety risk in the laboratory. To overcome this problem, we developed a new method to digest TiO2 nanoparticles using ammonium persulfate as a fusing reagent. The digestion technique requires short times to completion and optimally requires only 1 g of fusing reagent. The fusion method showed >95% recovery of Ti4+ from 6 μg mL?1 aqueous suspensions prepared from 10 μg mL?1 suspension of different forms of TiO2, including anatase, rutile and mixed nanosized crystals, and amorphous particles. These recoveries were greater than open hot-plate digestion with a tri-acid solution and comparable to microwave digestion with a tri-acid solution. Cations and anions commonly found in natural waters showed no significant interferences when added to samples in amounts of 10 ng to 110 mg, which is a much broader range of these ions than expected in environmental samples. Using ICP-MS for analysis, the method detection limit (MDL) was determined to be 0.06 ng mL?1, and the limit of quantification (LOQ) was 0.20 ng mL?1. Analysis of samples of untreated and treated wastewater and biosolids collected from wastewater treatment plants yielded concentrations of TiO2 of 1.8 and 1.6 ng mL?1 for the wastewater samples, respectively, and 317.4 ng mg?1 dry weights for the biosolids. The reactions between persulfate ions and TiO2 were evaluated using stoichiometric methods and FTIR and XRD analysis. A formula for the fusing reaction is proposed that involves the formation of sulfate radicals. 相似文献
This work address a number of fundamental issues and concepts related to local thermal non-equilibrium and the heat flux bifurcation phenomenon in porous media. Different types of heat flux bifurcation phenomenon are discussed in relation to previous works by the authors. 相似文献