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131.
132.
The most important design parameters for roller presses can be referred to flow and compression characteristics of bulk materials. Usually the flow properties are measured in the low stress range 1–50 kPa at the shear rate of about 1 mm/min. But this does not fit the stress regimes in the roller press. Therefore, the compression and flow behavior of the powder have to be investigated at higher pressures, shear rates, and shear displacements. These properties of bulk materials in the so-called medium pressure range 50–1000 kPa can be analyzed using a press shear cell. Tests were implemented with limestone, bentonite, and microcrystalline cellulose at average 23°C powder bed temperature using shear rates from 0.00042 to 0.042 m/s and a more realistic preshear displacement from 0.1 to 2 m for practical applications in powder compaction. Physical observation based compression functions were developed for the low and medium pressure range, which include simple equations for the compression rate and specific compression work. 相似文献
133.
ABSTRACT Two-dimensional finite element (FE) compressive stress analyses were carried out on the particle compound material to understand the stress pattern distributions before cracking. FE analysis was followed by discrete element (DE) simulation. A study of the crack propagating mechanism in a particle was represented by a model material that typifies pellets of high-strength pressed agglomerate building materials. For this, concrete spheres of strength category B35 (compressive strength 35 N/mm2) were used. It was observed that the ring tensile stress is responsible for the crack initiation in the spherical particle compounds. 相似文献
134.
135.
Juodeikiene G Basinskiene L Vidmantiene D Makaravicius T Bartkiene E 《Journal of the science of food and agriculture》2012,92(1):84-91
BACKGROUND: The efficiency of bioethanol production from wheat biomass is related to the quality of end products as well as to safety criteria of co‐products such as distiller's dried grains with solubles (DDGS). The inclusion of a new biocatalyst for non‐starch polysaccharide degradation in fermentation processes could be one of the solutions. The objective of this study was to evaluate the influence of β‐xylanases in combination with traditional amylolytic enzymes on the efficiency of bioethanol production and DON detoxification during fermentation of Fusarium‐contaminated wheat biomass with high concentration of deoxynivalenol (DON; 3.95 mg kg?1). RESULTS: The results showed that the negative effect of Fusarium spp. on yield and quality of bioethanol could be eliminated by the application of Trichoderma reesei xylanase in combination with amylolytic enzymes. This technological solution allowed to increase the concentration of ethanol in the fermented wort by 35.3% and to improve the quality of bioethanol by decreasing the concentrations of methanol, methyl acetate, isoamyl and isobutyl alcohols. Mass balance calculations showed that DDGS was the main source of DON contamination, comprising 74% of toxin found in wheat biomass. By using new enzyme combination for wheat biomass saccharification, a higher level of detoxification (41%) of DON was achieved during the fermentation process. CONCLUSION: The addition of Trichoderma reesei xylanase played a positive role in bioethanol production from Fusarium‐contaminated wheat biomass, indicating that the yeast‐growing medium was enriched during the enzymatic treatment. Copyright © 2011 Society of Chemical Industry 相似文献
136.
Marie N. Taylor Wu Zhou Tomas Garcia Benjamin Solsona Albert F. Carley Christopher J. Kiely Stuart H. Taylor 《Journal of Catalysis》2012,285(1):103-114
Titania-supported palladium catalysts modified by tungsten have been tested for the total oxidation of propane. The addition of tungsten significantly enhanced the catalytic activity. Highly active catalysts were prepared containing a low loading of 0.5 wt.% palladium, and activity increased as the tungsten loading was increased up to 6 wt.%. Catalysts were characterised using a variety of techniques, including powder X-ray diffraction, laser Raman spectroscopy, X-ray photoelectron spectroscopy, temperature-programmed reduction and aberration-corrected scanning transmission electron microscopy. Highly dispersed palladium nanoparticles were present on the catalyst with and without the addition of WOx. However, the addition of WOx slightly increases the average palladium particle size, and there was some evidence for the Pd forming epitaxial islands on the support in the tungsten-doped samples. Surface analysis identified a combination of Pd0 and Pd2+ on a Pd/TiO2 catalyst, whereas all of the Pd loading was found in the form of Pd2+ with the addition of tungsten into the catalysts. At low tungsten loadings, isolated monotungstate and some polytungstate species were highly dispersed over the titania support. The concentration of polytungstate species increased as the loading was increased, and it was also promoted by the presence of palladium. The coverage of the highly dispersed tungstate species over the titania also increased as the tungsten loading increased. Some tungstate species were also found to be associated with the palladium oxide particles, and there was an enrichment of oxidised tungsten species at the peripheral interface of the palladium oxide nanoparticles and the titania. Sub-ambient temperature–programmed reduction experiments identified an increased concentration of highly reactive species on catalysts with palladium and tungsten present together, and we propose that the new WOx-decorated interface between PdOx and TiO2 particles may be responsible for the enhanced catalytic activity in the co-impregnated catalysts. 相似文献
137.
138.
Koutny T 《IEEE transactions on information technology in biomedicine》2012,16(1):136-142
Glucose is an important source of energy for cells. In clinical practice, we measure glucose level in blood and interstitial fluid. Each method has its pros and cons, and both levels correlate with each other. As the body tries to maintain the glucose level within a particular range to avoid adverse effects, it is desirable to predict future glucose levels in order to aid provided health care. We can see this desire in research, e.g., research on glucose transporters of cells. As yet another example, we can see it with diabetic patients, patients in a metabolic intensive care unit, particularly. In this paper, a glucose level prediction method is proposed. 相似文献
139.
Patoka P Skeren T Hilgendorff M Zhi L Paudel T Kempa K Giersig M 《Small (Weinheim an der Bergstrasse, Germany)》2011,7(21):3096-3100
The transmission of light through a metallic film stack on a transparent substrate, perforated with a periodic array of cylindrical holes/nanocavities, is studied. The structure is fabricated by using self-assembled nanosphere lithography. Since one layer in the film stack is made of a ferromagnetic metal (iron), exposure of the structure to a solution containing iron oxide nanoparticles causes nanoparticle accumulation inside the nanocavities. This changes the dielectric constant inside the nanocavities and thus affects the light transmission. Simulations are in good agreement with experiment, and show large sensitivity of the response to the amount of iron oxide nanoparticles deposited. This could be used in various sensor applications. 相似文献
140.
From time immemorial people dealt with size reduction processes (mill, mineral liberation, etc.). As time has passed industrial units for comminution processes have become larger and more sophisticated, but still they perform with low efficiencies [1], [2] and [3]. The strength of a particle is one of its most crucial characteristics due to the mechanical stresses experienced by each particle within an industrial unit. This is because the final size of particles is mostly dependant on the strength distribution of the raw material [4]. In this present study, the ability of a number of statistical formulations to accurately describe the strength distribution of particles was examined. Additionally, selected equations were analyzed and a general expression including the effect of the material and particle size was developed. A number of approaches to define particle strength were considered, and strength in terms of crushing force was chosen. Particle strength in terms of force and in terms of energy was also compared and found to be size independent. Finally, particle strength in terms of stress was examined and compared to the particle strength in terms of force.The ability to describe the compression strength distribution will significantly improve the accuracy of the comminution processes simulation, design and optimization. 相似文献