Reviewing the need for gaming in education to accommodate the net generation

There is a growing interest in the use of simulations and games in Dutch higher education. This development is based on the perception that students belong to the ‘gamer generation’ or ‘net generation’: a generation that has grown up with computer games and other technology affecting their preferred learning styles, social interaction patterns and technology use generally. It is often argued that in education this generation prefers active, collaborative and technology-rich learning, i.e. learning methods that involve extensive computer use and collaboration among students. Gaming is then proposed as a new teaching method which addresses these requirements. This article presents the results of a survey which studied whether this discourse is also applicable to higher education students from the Netherlands and whether games, considered as active, collaborative and technology-rich learning experiences, are of greater importance in the formal education of today’s students. Of 1432 respondents from eight Dutch institutes of higher education surveyed between 2005 and 2009, about 25% fit our criteria of being a clear representative of the net generation. Furthermore, our analysis shows that there is little difference, and no statistically significant difference, in active, collaborative and technology-rich learning preferences between the representatives and non-representatives of the net generation. Furthermore, no large or statistically significant differences were found between representatives and non-representatives of the net generation with respect to the value they accorded to gaming in education. Overall our dataset did not fit the expectations raised by the net generation theory, with the percentage of students who fit the criteria being much lower than expected. However, regardless of whether they represented the net generation or not, in general our respondents preferred collaborative and technology-rich learning and deemed games a valuable teaching method.     

Hybrid Cooling Towers in a Free‐Cooling Application: Modeling and Field Measurement Verification

The energy‐saving potential of free cooling in chilled‐water systems was investigated. As a preliminary study, simulation was used to quantify the performance of free cooling in a given reference system. To reduce the computational effort for the simulation of long time periods, simplified models for dry and evaporative cooling were developed. The simulation results indicate that free cooling reduces the electric energy demand for cold supply almost by half. In a follow‐up investigation, free cooling was implemented in the reference system. The actual energy savings showed good agreement with the simulation forecasts and confirmed the feasibility of the concept.     

Numerical simulations of comminution slurries over complex topographies: Putting together CFD and pipeline integrity

The use of computational fluid dynamics gives new and interesting insights for risk analysis of cross-country ore hydraulic transport operations. In particular, they offer the possibility to predict, with reasonable accuracy, the progression and final condition of spills driven by pipeline leaks at selected locations, at a relatively modest computational cost. In this work, a depth-averaged, two-dimensional numerical model is used to simulate an ore concentrate pipeline rupture and subsequent spill, reproduced as a constant flow condition at the leak point. Although the model is well suited to solve the governing flow equations on arbitrary topographies by means of digital elevation models, two specific locations featuring relatively mild and steep slopes, are analysed with regard to their implications on the potential requirements for emergency team response. Results, obtained using different slurry rheologies, are compared with those obtained using a simpler, common flow resistance model derived for water flowing over rough surfaces.     

Title: Using Alignment and 2D Network Simulations to Study Charge Transport Through Doped ZnO Nanowire Thin Film Electrodes

Factors affecting charge transport through ZnO nanowire mat films were studied by aligning ZnO nanowires on substrates and coupling experimental measurements with 2D nanowire network simulations. Gallium doped ZnO nanowires were aligned on thermally oxidized silicon wafer by shearing a nanowire dispersion in ethanol. Sheet resistances of nanowire thin films that had current flowing parallel to nanowire alignment direction were compared to thin films that had current flowing perpendicular to nanowire alignment direction. Perpendicular devices showed ～5 fold greater sheet resistance than parallel devices supporting the hypothesis that aligning nanowires would increase conductivity of ZnO nanowire electrodes. 2‐D nanowire network simulations of thin films showed that the device sheet resistance was dominated by inter‐wire contact resistance. For a given resistivity of ZnO nanowires, the thin film electrodes would have the lowest possible sheet resistance if the inter‐wire contact resistance was one order of magnitude lower than the single nanowire resistance. Simulations suggest that the conductivity of such thin film devices could be further enhanced by using longer nanowires.     

Ethanol and water capacities of alcohols: A molecular dynamics study

The extended hydrogen bond networks formed by alcohols are good indicators of their capacities to hold water. Results from molecular dynamics simulations on 24 linear alcohol isomers containing 6-12 carbon atoms show the effects of hydroxyl location on bulk hydrogen-bonded structures. Calculated oxygen-oxygen radial distributions obtained from simulations were correlated to experimental liquid-liquid solvent extraction studies involving ternary water/ethanol/alcohol systems. It was found that hydroxyl group location determines the primary structure of the bulk alcohol's hydrogen bond network and that an alcohol's capacity for water correlates directly to the size of this network.     

Assessment of large eddy and RANS stirred tank simulations by means of LDA

Large eddy simulations (LES) and Reynolds-averaged Navier-Stokes (RANS) calculations were performed on the flow in a baffled stirred tank, driven by a Rushton turbine at Re=7300. The LES methodology provides detailed flow information as velocity fluctuations are resolved down to the scale of the numerical grid. The Smagorinsky and Voke subgrid-scale models used in the LES were embedded in a numerical lattice-Boltzmann scheme for discretizing the Navier-Stokes equations, and an adaptive force-field technique was used for modeling the geometry. The uniform, cubic computational grid had a size of 240³ grid nodes. The RANS calculations were performed using the computational fluid dynamics code CFX 5.5.1. A transient sliding mesh procedure was applied in combination with the shear-stress-transport (SST) turbulence closure model. The mesh used for the RANS calculation consisted of 241464 nodes and 228096 elements (hexahedrons). Phase-averaged and phase-resolved flow field data, as well as turbulence characteristics, based on the LES and RANS results, are compared both mutually and with a single set of experimental data.     

Gas Flow and Particle Transport and Deposition in a Pilot-Scale Furnace

The present work describes a computer simulation study of gas flow and particle transport and deposition in a pilot-scale furnace with cooling system. The Gambit code is used to generate the geometry and the computational grid. An unstructured mesh is generated for the pilot-scale boiler. The FLUENT code is used for evaluating the gas mean velocity, turbulence fluctuation energy, and mean pressure, as well as temperature fields and chemical species concentrations. The particle equation of motion includes the nonlinear drag, gravity, Brownian, lift, and thermophoretic forces. The gas velocity and thermal conditions in the furnace are studied. Ensembles of particle trajectories are generated and statistically analyzed. Particle deposition rates on different walls are evaluated, and the effect of particle size is studied.     

CFD simulations of bubbling beds of rough spheres

Hydrodynamics of three-dimensional gas-solid bubbling fluidized beds are numerically analyzed. The particle-particle interactions are simulated from the kinetic theory for flow of dense, slightly inelastic, slightly rough sphere proposed by Lun [1991. Kinetic theory for granular flow of dense, slightly inelastic, slightly rough sphere. Journal of Fluid Mechanics 233, 539-559] to account for rough sphere binary collisions and the frictional stress model proposed by Johnson et al. [1990. Frictional-collisional equations of motion for particulate flows and their application to chutes. Journal of Fluid Mechanics 210, 501-535] to consider the frictional contact forces between particles. The present model is evaluated by measured particle distributions and velocities of Yuu et al. [2001. Numerical simulation of air and particle motions in group-B particle turbulent fluidized bed. Powder Technology 118, 32-44] and experimental bed expansion of Taghipour et al. [2005. Experimental and computational study of gas-solid fluidized bed hydrodynamics. Chemical Engineering Science 60, 6857-6867]. Our computed results indicated that the present model gives better agreement with experimental data than the results from original kinetic theory for frictionless slightly inelastic sphere of Ding and Gidaspow [1990. A bubbling fluidization model using kinetic theory of granular flow. A.I.Ch.E. Journal 36, 523-538] with and without solid friction stress model.     

Insight from Atomistic Simulations of Protonation Dynamics at the Nanoscale

In this paper, we give an overview of the role of molecular dynamics (MD) simulations in the field of proton exchange membranes. We focus on structural and dynamical findings regarding the topology of hydrogen bond networks and proton diffusion. On the one hand, findings about water‐containing polymer electrolyte membrane fuel cell materials, such as Nafion and liquid containing pore materials are discussed. On the other hand, proton conduction in water‐free systems is elucidated. Here, the focus lies on phosphonic acids, which possess a rigid structure, and polymers based on phosphonic acids.     

A Comparison of the Drying Simulation Codes Transpore and Wood2D which are used for the Modelling of Two-Dimensional Wood Drying Processes

ABSTRACT

This study is devoted to investigating the heat and mass transfer phenomena that occur during the convective drying of wood at high temperatures. A comparison will be made between an existing two-dimensional computer code known as Transpore. which was developed by Perre in France, and another two-dimensional code which was developed independently by Turner in Australia. Both numerical codes use a comprehensive set of macroscopic equations to describe the drying process, and most importantly treat the anisotropic behaviour of the wood. The porous medium is defined by three state variables: temperature, moisture content and gaseous pressure and the numerical simulation codes allow the evolution of the distributions of these state variables to be analysed throughout the drying process. The numerical investigation presented in this research work will compare the results obtained from both simulation codes and comments will be made on their consistencies. The influence that the drying air characteristics (moist air and super-heated stream) have on the overall drying kinetics, together with the effect that varying the mesh structure or changing the relative permeability curves have on the results will be throughly scrutinised.