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排序方式: 共有908条查询结果,搜索用时 234 毫秒
61.
Klaas van Alphen Paul M. Noothout Marko P. Hekkert Wim C. Turkenburg 《Renewable & Sustainable Energy Reviews》2010,14(3):971-986
Carbon capture and storage (CCS) is seen as an important solution to solve the twin challenge of reducing GHG emissions, while utilizing fossil fuel reserves to meet future energy requirements. In this study an innovation systems perspective is applied to review the development of CCS technologies in the US between 2000 and 2009 and to come up with policy recommendations for technology managers that wish to accelerate the deployment of CCS. The analysis describes the successful built-up of an innovation system around CCS and pinpoints the key determinants for this achievement. However, the evaluation of the system's performance also indicates that America's leading role in the development of CCS should not be taken for granted. It shows that the large CCS R&D networks, as well as the extensive CCS knowledge base, which have been accumulated over the past decade, have not yet been valorized by entrepreneurs to explore the market for integrated CCS concepts linked to power generation. Therefore, it is argued that the build-up of the innovation system has entered a critical phase that is decisive for a further thriving development of CCS technologies in the US. This study provides a clear understanding of the current barriers to the technology's future deployment and outlines a policy strategy that (1) stimulates technological learning; (2) facilitates collaboration and coordination in CCS actor networks; (3) creates financial and market incentives for the technology; and (4) provides supportive regulation and sound communication on CCS. 相似文献
62.
Mladen Brnčić Tomislav Bosiljkov Marko Ukrainczyk Branko Tripalo Suzana Rimac Brnčić Sven Karlović Damir Karlović Damir Ježek Dražen Vikić Topić 《Food and Bioprocess Technology》2011,4(7):1296-1306
Production of extrudates from cereals is an often-used technological process in today’s world food industry. Extrudates from
corn flour produced using the twin-screw extrusion process and enriched with whey protein concentrate represent high-quality
source of proteins and fats. Whey protein concentrate (WPC) as a valuable source of proteins and minerals is one of the highest-quality
components for possible extrudate enrichment. In this paper, the influence of various WPC addition and some extrusion process
parameters such as feed moisture content (
Q\textH\text2 \textO Q_{{{\text{H}}_{\text{2}} {\text{O}}}} ) on physicochemical properties of directly expanded corn flour extrudates manufactured in twin-screw co-rotating extruder
was investigated. Whey protein concentrate was added in the following ratios 7.5%, 15% and 22.5% and water in 10.08, 12.18
and 14.28 L/h. Final composition of products is determined with measuring of protein, fat and water shares, water absorption
index (WAI) and water solubility index (WSI). With added WPC and with increase of water volume flow, there was a significant
rise in total protein, fat and water content in final products, as well as lowering of WSI and rising of WAI indexes. The
statistical analysis of the obtained data shows that the lowest WSI and the highest WAI had samples with the largest share
of WPC (22.5%) and water volume flow of 14.28 L/h. Colour is measured for each sample, and results were represented with hue
angle (H), chroma (C) and lightness (L) values. Process parameters, WPC and
Q\textH\text2 \textO Q_{{{\text{H}}_{\text{2}} {\text{O}}}} influence the increase of saturation of C and lightness of L colour value, while H value stays unchanged. Mean value of H
was 90.14 ± 1.06, which corresponds to dominance of yellow colour of samples. 相似文献
63.
Josip Brnic Marko Canadija Goran Turkalj Domagoj Lanc 《Canadian Metallurgical Quarterly》2010,136(9):1083-1089
This paper presents the temperature dependence of the mechanical properties of structural high-strength low-alloy (HSLA) ASTM A709 Gr50 steel (En10025: S355 JO; DIN: ST 52-3U). Engineering stress-strain diagrams at lowered and elevated temperatures are presented. Creep responses for selected constant stresses at selected temperatures are also presented and are fit with a rheological model. Additionally, a relation between impact toughness and fracture toughness is proposed and is validated using results from notch impact tests on a Charpy pendulum impact machine. 相似文献
64.
Vujasinovic Marko Ivezic Nenad Kulvatunyou Boonserm Barkmeyer Edward Missikoff Michele Taglino Francesco Marjanovic Zoran Miletic Igor 《Internet Computing, IEEE》2010,14(1):52-63
The authors discuss a semantic-mediation architecture to advance traditional approaches for standards-based business-to-business (B2B) interoperability. The architecture is supported by the Athena Knowledge Representation and Semantics Mediation tool suite. Initial experimentations with the architecture and the toolset offer discussions of key architectural and functional aspects and suggest directions for future tools enhancements. 相似文献
65.
Rheological behavior of five different pectin-enriched products obtained from a cell wall enriched powder of butternut (Cucurbita moschata Duch ex Poiret) was evaluated through flow and oscillatory assays. The product SE was obtained through treatment with citrate buffer; C1 and C2 were obtained using cellulase and different enzyme-substrate ratios while H1 and H2 resulted from hemicellulase treatment at different levels. SE- and H1-pectin-enriched fractions showed the best performance as thickeners as indicated by their highest Newtonian viscosities and time constants on shear-thinning along the flow. These fractions showed a structure with the highest density of interactions between the hydrated macromolecules when solutions were evaluated at rest. Fractions obtained with a higher activity of hemicellulase (H2) or with the lowest activity of cellulase assayed (C1) showed the same degree of structure when evaluated at rest, while C2-fraction presented the lowest density of macromolecular interactions in water, behaving as a diluted hydrocolloid solution as confirmed by its fitting to the Cox-Merz rule. Molecular weight distribution of polysaccharide fractions along with chemical composition helped to explain the rheological behavior of these isolated fractions which contained between 39 and 78 g of galacturonic acid per 100 g of product. With the exception of C2 fraction, pectin-enriched products isolated from butternut showed an interesting range of thickening properties and can be used as thickeners in the food industry. 相似文献
66.
Brain is one of the richest organs in lipid content. Phospholipids (glycerophospholipids and sphingolipids) are important building blocks of cell membranes, which provide an optimal environment for protein interactions, trafficking and function. Because of that, alterations in their cellular levels could lead to different pathogenic processes in the brain, such as in Alzheimer’s disease (AD), the most common type of dementia among older populations. There is increasing evidence that phospholipid changes occur during pathogenic processes in AD. It is known that lipids are tightly connected with metabolism of the Amyloid Precursor Protein (APP), which produces Amyloid-beta peptide (Aβ), the main component of senile plaques, which represent the main pathological hallmark of AD. However, the mechanism(s) of the lipid-effect on Aβ metabolism and AD pathogenesis is still not completely understood. This review summarizes the current knowledge on phospholipid changes occurring during normal aging and discusses phospholipid changes in the human brain associated with different stages of AD, as well changes in the cerebrospinal fluid and blood/plasma, which are interesting potential biomarkers for AD diagnosis and disease monitoring. At the end, we have discussed future perspectives of phospholipid changes as potential biomarkers and as targets for development of novel treatment strategies against AD. 相似文献
67.
Justin Činkelj Roman Kamnik Peter Čepon Matjaž Mihelj Marko Munih 《Automation in Construction》2010,19(7):954-963
Automatization is supposed to improve working conditions and safety in the construction industry, as it already did in manufacturing industries. This paper presents the development of a robotic control system for a commercially available hydraulic telescopic handler. The target application for the telescopic handler is semi-automated assembly of facade panels. The base handler was upgraded with two additional hydraulic axes, position sensors and closed-loop control system, while the original handler safety assurance mechanisms were preserved. The control approach is based on a PI controller with velocity feedforward and valve overlap compensation. The direct and inverse kinematic models of handler mechanism were developed to enable control of end-effector motion along a straight line in the Cartesian coordinate system. The motion performances were evaluated following the ISO 9283 standard with payload of 2000 kg. Results show the repeatability of positioning bellow 7.0 mm and the straight line tracking error smaller than 63 mm. 相似文献
68.
69.
Marko Lyytikäinen Taija Hämäläinen Jari Hämäläinen 《International Journal of Heat and Mass Transfer》2009,52(5-6):1132-1137
In this study, the depth-averaged flow and energy equations for plate heat exchangers are presented. The equations are derived by integrating the original 3D flow and energy equations over the height of the gap between the bottom and top plates. This approach reduces the equations from 3D to 2D but still takes into account the frictions on the surfaces and heat transfer through the plates. The depth-averaging reduces the elapsed time of CFD simulations from hours to minutes. Thus, it is very practicable modelling method in real time design work. 2D CFD simulations with depth-averaged equations are compared with full 3D models for five different corrugation angles and corrugation lengths. The simulation results show that the 2D model predicts with relatively good accuracy the profile of the pressure drop and the temperature change as a function of the corrugation angle and the function of the corrugation length. In order to get more extensive information about the significance of the different geometry parameters on the efficiency of the heat exchanger, we simulated 30 different geometries with the fast 2D model. The results suggest that the temperature change is not as sensitive for the geometrical modifications as the pressure drop. 相似文献
70.
The paper presents a simple but efficient new numerical scheme for the integration of nonlinear constitutive equations. Although it can be used for the integration of a system of algebraic and differential equations in general, the scheme is primarily developed for use with the direct solution methods for solving boundary value problems, e.g. explicit dynamic analysis in ABAQUS/Explicit. In the developed explicit scheme, where no iteration is required, the implementation simplicity of the forward-Euler scheme and the accuracy of the backward-Euler scheme are successfully combined. The properties of the proposed NICE scheme, which was also implemented into ABAQUS/Explicit via User Material Subroutine (VUMAT) interface platform, are compared with the properties of the classical forward-Euler scheme and backward-Euler scheme. For this purpose two highly nonlinear examples, with the von Mises and GTN material model considered, have been studied. The accuracy of the new scheme is demonstrated to be at least of the same level as experienced by the backward-Euler scheme, if we compare them on the condition of the same CPU time consumption. Besides, the simplicity of the NICE scheme, which is due to implementation similarity with the classical forward-Euler scheme, is its great Advantage. 相似文献