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921.
We investigated the impact of the enhanced sulphur content of feedstocks during the production of gas oil with bio-component content in one catalytic step, on a NiMo/Al2O3 catalyst from sunflower oil-containing gas oil. The mixing of vegetable oil reduces the efficiency of hydrodesulphurization compared to the pure gas oil feedstock, but using the favourable process parameter combination high scale desulphurization can be achieved. 相似文献
922.
923.
We consider the problem of model selection in the batch (offline, non-interactive) reinforcement learning setting when the goal is to find an action-value function with the smallest Bellman error among a countable set of candidates functions. We propose a complexity regularization-based model selection algorithm, $\ensuremath{\mbox{\textsc {BErMin}}}$ , and prove that it enjoys an oracle-like property: the estimator??s error differs from that of an oracle, who selects the candidate with the minimum Bellman error, by only a constant factor and a small remainder term that vanishes at a parametric rate as the number of samples increases. As an application, we consider a problem when the true action-value function belongs to an unknown member of a nested sequence of function spaces. We show that under some additional technical conditions $\ensuremath{\mbox{\textsc {BErMin}}}$ leads to a procedure whose rate of convergence, up to a constant factor, matches that of an oracle who knows which of the nested function spaces the true action-value function belongs to, i.e., the procedure achieves adaptivity. 相似文献
924.
Deborah S. Gross Markus E. Galli Philip J. Silva Sylvia H. Wood Don-Yuan Liu Kimberly A. Prather 《Aerosol science and technology》2013,47(2):152-163
Individual aerosol particles emitted from light-duty vehicles (LDV) and heavy-duty vehicles (HDV) were sampled in the Caldecott Tunnel (Berkeley, CA) using an aerosol time-of-flight mass spectrometer (ATOFMS). This instru ment determines both size and composition information of individual particles in real time. From the composition of individual particles, in conjunction with knowledge of the traffic patterns in the Caldecott Tunnel, information about the source of the particles can be determined. Based upon chemical composition, three main types of particles were detected: particles with significant mass spectral signal due to polycyclic aromatic hydrocarbons (PAH), elemental carbon (soot) particles, and inorganic particles containing substantial signal due to ions includ ing Al+, Ca+, Fe+, Ba+ and BaO+. Preliminary analysis of these classes shows that they encompass 61.4%, 10.3%, and 11.0%, respectively, of the total number of particles sampled with the ATOFMS instrument in 3 h, heavy traffic sampling periods, in an LDV-only bore of the tunnel. They represent 57.4%, 11.8%, and 18.0%, respectively, of the total number of particles sampled with the ATOFMS instrument in a 3 h sampling period in a mixed traffic (HDV and LDV) bore of the tunnel. 相似文献
925.
Tamalia C.M. Julien Manopriya Devisetty Subramanyam Hruday Chand Katakam Sanboh Lee Sylvia Thomas Julie P. Harmon 《Polymer Engineering and Science》2019,59(4):838-845
A novel, high performance ultrasoft polycarbonate polyurethane polymer was electrospun and tested against its bulk material to investigate changes in its thermal and mechanical properties. A series of fiber membranes was processed via solution electrospinning using a 90:10 ratio of dimethyformamide‐ethylacetate. Thermal, mechanical, and structural properties were obtained using thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), wide‐angle X‐ray scattering (WAXS), and tensile testing. TGA revealed that thermal stability of the membranes increased with the concentration of polymer solution used in spinning. DSC showed no variation in glass transition temperatures while the melting point regions varied noticeably with spinning conditions. WAXS profiles in solution casts films and electrospun mats showed the presence of diffraction peaks related to ordered crystal lamellae in the hard segment region at lower concentrations; these intensified after electrospinning. As the concentration of the polymer solution increased, the molecular orientation decreased. Tensile testing showed a significant increase in tensile strength at 18 w/v% fiber membranes. The ability of the polymer membrane characteristics to be tuned by processing conditions is of great interest in applications related to biotechnology, drug delivery, and implantable polymeric systems. POLYM. ENG. SCI., 59:838–845, 2019. © 2019 Society of Plastics Engineers 相似文献
926.
Marc Londo Sander Lensink André Wakker Günther Fischer Sylvia Prieler Harrij van Velthuizen Marc de Wit André Faaij Martin Junginger Göran Berndes Julia Hansson Andrea Egeskog Henrik Duer Jeppe Lundbaek Grzegorz Wisniewski Adam Kupczyk Kurt Könighofer 《Biomass & bioenergy》2010,34(2):244-250
The current hot debate on biofuels calls for a balanced and realistic long-term strategy for biofuels. The REFUEL project provides several ingredients for such a strategy. Analyses in this project indicate that domestically produced biofuels can cover a significant share of EU fuel demand in the coming decades, with the EU-12 new member states and Ukraine as most promising regions. This potential can be realised with residual streams and on existing agricultural land, without conversion of e.g. nature reserves. Second generation biofuels are essential for the long-term success of biofuels due to their superior performance in many ways. But generally, the key challenge for the near future would be how to enhance the development of biofuels in a responsible way, i.e. stimulating the production chains with the best performance, and preventing negative impacts e.g., by paying careful attention to possible system impacts of biofuel production such as indirect land use changes and rising food prices. Finally, 2nd generation biofuels require specific policy: the precursor role of 1st generation is overrated, both in technical terms as well as in their role as market precursors. When it comes to synergies, 2nd generation biofuels might benefit more from other developments in the energy sector, such as initiatives in co-firing of biomass for (heat and) power, than from 1st generation biofuels, also because of the public resistance that the latter induce. 相似文献
927.
Ufuk Utku Turuncoglu Sylvia MurphyCecelia DeLuca Nuzhet Dalfes 《Computers & Geosciences》2011,37(7):943-952
Many separate tasks must be performed to configure, run, and analyze Earth system modeling applications. This work is motivated by the complexities of running a large modeling system on a high performance network and the need to reduce those complexities, particularly for the average user. Scientific workflow systems can be used to simplify these task and their relationships, although how to implement such systems is still an open research area. In this paper, we present a methodology to combine a scientific workflow and modeling framework approach to create a standardized work environment and provide a first example of a self-describing Earth system model. We then show the results of an example workflow that is based on the proposed methodology. The example workflow allows running and analyzing a global circulation model on both a grid computing environment and a cluster system, with meaningful abstractions for the model and computing environment. As can be seen through this example, a layered approach to collecting provenance and metadata information has the added benefit of documenting a run in far greater detail than before. This approach facilitates exploration of runs and leads to possible reproducibility. 相似文献
928.
T. Morales de Luna M. J. Castro D��az C. Par��s Madro?al 《Journal of scientific computing》2011,48(1-3):258-273
This article focuses on the simulation of the sediment transport by a fluid in contact with a sediment layer. This phenomena can be modelled by using a coupled model constituted by a hydrodynamical component, described by a shallow water system, and a morphodynamical one, which depends on a solid transport flux given by some empirical law. The solid transport discharge proposed by Meyer-Peter & Müller is one of the most popular but it has the inconvenient of not including pressure forces. Due to this, this formula produces numerical simulations that are not realistic in zones where gravity effects are relevant, e.g. advancing front of the sand layer. Moreover, the thickness of the sediment layer is not taken into account and, as a consequence, mass conservation of sediment may fail. Fowler et al. proposed a generalization that takes into account gravity effects as well as the thickness of the sediment layer which is in better agreement with the physics of the problem. We propose to solve this system by using a path-conservative scheme for the hydrodynamical part and a duality method based on Bermúdez-Moreno algorithm for the morphodynamical component. 相似文献
929.
930.