96 research outputs found
Being There VR Museum Trailer.
No full textMarnix S. van Gisbergen (project leader), Shima Rezaei Rashnoodi (project leader), Karlijn van Baal (Producer), Kevin Otto (Director), Leonie Palm (DOP), Adinda Berends (Audio), Joost Scheffers (Editing), Danny Linssen (Supervisor)
Design For Manufacturing (DFM) in Nano-CMOS Era
No full textThis paper overviews DFM for IC design In nano-CMOS technologies. Process/device issues relevant to the manufacturability of ICs in advanced CMOS technologies will be presented first before an exploration on process/device modeling for DFM is done. The discussion also covers a brief introduction of DFM-aware of design flow and EDA efforts to better handle the design-manufacturing interface in very large scale IC design environment.Engineering, Electrical & ElectronicNanoscience & NanotechnologyCPCI-S(ISTP)
Digital Fabrication and Component Optimization Using DFM: Integrating Two-dimensional Cutting and Three-dimensional Milling in Wood Panel Fabrication
No full textThis research explores new ways to integrate manufacturing knowledge in to design phases. Through the use of design for manufacturing (DfM) concept, and looking at relations between its potential application in component design and its implementation using digital manufacturing technologies, the author implemented a DfM model that varies from previous models by incorporated learning in the process. This process was based on, a knowledge systematization process, and the incremental development and refinement of design heuristics and metrics. Subsequently the attempt on this research is twofold. One is to realize a process to capture and organize manufacturing knowledge, and second to organize that knowledge and make it available as a DfM model for component design using specific CNC technology
Integrated CO<sub>2</sub>capture and selective conversion to syngas using transition-metal-free Na/Al<sub>2</sub>O<sub>3</sub>dual-function material
No full textIntegrated CO2 capture and conversion (ICCC) using dual-function materials (DFMs) is one of the key technologies for addressing critical global environmental and energy issues. DFMs generally consist of alkali or alkaline earth metals for CO2 capture and transition metal catalysts for CO2 conversion. In this study, we studied the ICCC to CO using transition-metal-free DFMs to demonstrate their potential to directly produce syngas from atmospheric-level CO2. Among the DFMs prepared herein, Na/Al2O3 exhibited excellent performance and achieved a CO2 conversion exceeding 90% and CO selectivity exceeding 95% at a reaction temperature of 450-500 °C. Na/Al2O3 maintained its capture and conversion capacity throughout a 50-cycle stability test without significant deactivation. Furthermore, in the scale-up experiments using Na/Al2O3 DFM, a syngas-like mixture an H2/CO molar ratio of 3.3 (48.1 vol% H2 and 14.5 vol% CO) was directly obtained from 400 ppm CO2. These results suggest that ICCC using the transition-metal-free Na/Al2O3 DFM may be practicable provided the CO2 capture capacity of the DFM is further improved while maintaining the aforementioned advantages. Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.ChemE/Catalysis Engineerin
Effect of supplementing direct-fed microbials on broiler performance, nutrient digestibilities, and immune responses
No full textDirect-fed microbials (DFM) are used to improve livestock health and performance. The effects of 2 DFM products, a blend of 3 Bacillus strains (DFMB) and a Propionibacterium spp. (DFMP), on broiler performance, nutrient utilization, and immune responses were investigated. Day-old (n=120) male broilers were divided into 24 groups of 5 birds and fed 3 wheat-based diets in mash form (8 groups per diet) from d 1 to 22. The control diet was fed without or with 7.5×104 cfu/g of either DFMB or DFMP. From d 19 to 21 fecal samples were collected for determination of total tract apparent retention (TTAR) of nutrients and AMEn. On d 21, feed intake and BW were determined. On d 22, 5 birds per treatment were killed by cervical dislocation to collect jejunal and ileal contents for determination of digesta viscosity and apparent ileal digestibility (AID) of nutrients, respectively, and ileum, cecal tonsil, and spleen tissues for Toll-like receptors (TLR) and cytokine expressions. Compared with the control, DFM did not affect BW gain and feed intake but DFMP reduced G:F (P<0.01). Compared with the control (2,875 kcal/kg), birds fed on DFMB and DFMP had higher AMEn (2,979 and 2,916 kcal/kg, respectively; P<0.05), whereas both DFM reduced the AID of DM (P<0.001) and CP (P<0.01). Furthermore, DFMP reduced TTAR of NDF (29.0 vs. 18.4%; P<0.001), whereas both DFM increased TTAR of DM and fat (P<0.001). Supplementing DFMP downregulated ileal expression of TLR-2b, IL-2, IL-4, IL-6, IL-10, and IL-13, whereas DFMB downregulated TLR-2b, IL-2, IL-4, and IL-6 in all 3 tissues, IL-10 in the spleen, and upregulated IL-13 in the spleen. In conclusion, the DFM did not improve performance but increased the AMEn of diet by possibly increasing DM and fat retention. Overall, both DFM showed an antiinflammatory effect in the ileum, but DFMB had more effects on local and systemic immunity than DFMP
Multi-level discrete fracture model for carbonate reservoirs
No full textThe main challenge for predictive simulation of carbonate reservoirs is associated with large uncertainties in the geological characterization with multiple features including fractures and cavities. This type of reservoirs requires robust and efficient forward-simulation capabilities to apply data assimilation or optimization technique under uncertainties. The interaction between reservoir matrix and various features introduces a complex multi-scale flow response driven by global boundary conditions. The Discrete Fracture Models (DFM), which represent fractures explicitly, is capable to accurately depict all important features of flow behavior. However, these models are constrained by many degrees of freedom when the fracture network becomes complicated. The Embedded DFM, which represents the interaction between matrix and fractures analytically, is an efficient approximation. However, it cannot accurately reproduce the effect of local flow conditions, especially when the secondary fractures are present. In this study, we applied a numerical upscaling of DFM a triple continuum model where large features are represented explicitly using the numerical EDFM and small features are upscaled as a third continuum. In this approach, we discretize the original geo-model with unstructured grid based on DFM and associate the mesh geometry with large features in the model. Using the global solution, we generate local boundary conditions for the model capturing the response of primary features to the flow. Applying local boundary conditions, we resolve all secondary features using a fine scale solution and update the local boundary conditions. This procedure is applied iteratively using the local-global-upscaling formalism. To demonstrate the accuracy of the Multi-Level Discrete Fracture Model, several realistic cases have been tested. By comparing with fine scale DFM solution and the traditional EDFM technique, we demonstrate that the proposed model is accurate enough to capture the flow behavior in complex fractured systems with advanced computational efficiency.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Reservoir Engineerin
A Multiscale Finite Volume Method for Discrete Fracture Modeling on Unstructured Grids
No full textA novel multiscale method for discrete fracture modeling on unstructured grids (MS-DFM) is developed. To this end, the DFM fine-scale discrete system is constructed using unstructured conforming cells for the matrix with lower-dimensional fracture elements placed at their interfaces. On this unstructured fine grid, MS-DFM imposes independent unstructured coarse grids for the fracture and matrix domains. While the conservative coarse-scale system is solved over these coarse-grid cells, overlapping dual-coarse blocks are also formed in order to provide local supports for the multiscale basis functions. To increase the accuracy, but maintaining the computational efficiency, fracture-matrix coupling is considered only for the basis functions inside the matrix domain. This results in additional (enriching) fracture basis functions in the matrix. By construction, basis functions form the partition of unity for both fracture and matrix sub-domains. Furthermore, to enable error reduction to any desired level, a convergent iterative strategy is developed, where MS-DFM is employed along with a fine-scale smoother in order to resolve low- and high-frequency modes in the error. The performance of MS-DFM is assessed for several 2D and 3D test cases. Specially, the method proves accurate for many test cases without any iterations. MS-DFM is the first of its kind, and extends the application of multiscale methods to unstructured discrete fracture models. As such, it provides a promising framework for real-field application of unstructured DFM.Civil Engineering and GeosciencesGeoscience & Engineerin
Direct and continuous conversion of flue gas CO<sub>2</sub> into green fuels using dual function materials in a circulating fluidized bed system
No full textCarbon capture and utilization (CCU) technologies, such as CO2 methanation, generally require energy-intensive CO2 capture and separation processes prior to catalytic CO2 conversion. In contrast, integrated CO2 capture and reduction (CCR) technologies that use dual function materials (DFM) can directly convert low-concentration CO2 in flue gas or atmosphere into high-concentration CH4 or CO. In this study, we demonstrate a circulating fluidized bed (CFB) approach to enable continuous operation of CCR. In the CFB approach, the DFM (Na/Ni/Al2O3) circulates between two bubbling fluidized beds to enable steady-state cyclic operation of (1) selective capture of CO2 in flue gas/air and (2) hydrogenation of the captured CO2. We succeeded in the continuous synthesis of CH4 with high CO2 capture efficiency (>88 %) and high H2 conversion (>85 %) yielding mainly CH4 (selectivity > 99 %) as the product at high concentration (>20 % CH4) using 2 % CO2/N2 as the model flue gas.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.ChemE/Catalysis Engineerin
Accurate numerical method to solve flux distribution of Poisson's equation
No full textThis paper proposes an accurate numerical method, the direct flux method (DFM), to solve fluxes directly for Poisson's equation. In DFM, fluxes are the variables to be solved in the system equations, where a flux is defined as an integral of the flux density across a certain finite-sized cross section. The system equation of the DFM is derived from two equations: an integral form of Poisson's equation obtained by using Gauss's divergence theorem and an integral form of the rotation-free nature of any scalar field from Stokes' theorem. In the numerical approach, no discretization error arises from Gauss's divergence theorem because it is represented as a sum of fluxes. Therefore, the discretization error is caused only by the integral form of the rotation-free nature. From the comparison between DFM, the finite difference method (FDM), and the finite volume method (FVM), we show that the accuracy of DFM is superior to that of FDM and FVM. However, DFM generally requires larger computational resources than other methods because the number of equations in DFM is more than that in other methods. To overcome this drawback, we also propose a faster algorithm than DFM, called FastDFM, which can reduce the number of equations without changing the accuracy. Hence, the proposed FastDFM produces results with the same accuracy as the DFM and with computation time almost the same as that of FDM and FVM
Improved Understanding of Naturally Fractured Reservoirs Using Data Assimilation
No full textNaturally fractured reservoirs can pose challenges for energy operations such as hydrocarbon production, CO2 storage, and geothermal energy production. Fluid flow in these reservoirs is greatly affected by fracture properties such as orientation and aperture, whose magnitude is mainly influenced by the stresses on the reservoir rocks. Simulating fractures and their behavior tends to be computationally intensive, but recent advances in Discrete Fracture Models (DFM) have successfully overcome computational complexity and allow for the explicit inclusion of discrete fractures in reservoir simulations. However, there are still challenges in dealing with uncertainties, including fracture aperture and the effect of in-situ stresses on the fracture surface and their effect on the fluid behavior. This study explores the use of data-assimilation techniques to help quantify these uncertainties. We combine a recent implementation of DFM on the Delft Advanced Research Terra Simulator (DARTS) with both ensemble and gradientbased data-assimilation methods. Our results show that data assimilation can help to understand the dynamic behavior of fluids in fractured reservoirs. Using this technique, we obtain a more accurate representation of the stresses acting on the reservoir and how they affect the fracture aperture. This information is essential for more efficient reservoir management.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Reservoir Engineerin
- …
