Research@ZaB: FDS Features for Pressure Loading Assessment Within the Context of the Train-Tunnel Model Development

The CFD model of the train-tunnel system, previously developed on proven analytical dependencies, is improved by the introduction of a tunnel cross-passage and the consideration of surface roughness. These additions bring the simulation setup closer to real conditions allowing to explore the FDS features in the evaluation of the aerodynamic effects occurring in a tunnel. Pressure and velocity patterns are obtained for the resulting model of a high-speed train in a tunnel with a cross-passage. The maximal and minimal pressure levels for the tunnel and the cross-passage spans are calculated to provide the data for the design phase and safety assessment. The approach to determine the most loaded surfaces of the tunnel and its inner structures, e.g. escape doors, for an estimation of their operational reliability is discussed. The study shows that the FDS software can be a helpful tool in assessing scenarios where the train-tunnel interaction is reviewed, though its applicable capabilities and set of features are largely dependent on the tasks to solve and need to be accurately adjusted.

Nonlinear Seismic Response Analysis of the Surrounding Rock-Tunnel System in the Mountain Areas Under SV Wave

The seismic responses and failure mechanisms of the tunnels embedded in the rock are quite different from those of the aboveground structures due to the dynamic interactions between tunnel and surrounding rock. In the previous studies, the tunnel models were under some extent of simplification without considering much of critical issues such as the three-dimensional (3D) characteristics, nonlinear mechanical properties or initial in-situ stress in the model, which are bound to bring the unpredictable errors in the evaluation of seismic response of tunnel-rock system. In this paper, some 3D nonlinear finite element models are established to evaluate the seismic response of surrounding rock-tunnel system in the mountain areas, considering the initial stress state of surrounding rock-tunnel system induced by gravity and excavation, General Mohr Coulomb nonlinear constitutive. Based on the proposed model, the optimal value of the longitudinal length of the model is firstly discussed to determine the value range of the model size. After that, a series of numerical parametric analyses are carried out to investigate the deformation of the surrounding rock. One important finding is that there exists a most unfavorable stress condition which makes the tunnel induce maximum seismic responses. Finally, the typical control variable method is employed to compare the results of the models established in this paper with those of the model considering or not some of significance factors, the comparison results further prove the necessity of establishing the 3D nonlinear model.

Analyzing Spatial Memory in a Virtual Reality-Based Subterranean Scenario: Implication for Military Augmented Reality Systems

Utilizing virtual reality (VR) has allowed the testing of new technology for military missions not available previously, such as using head-mounted augmented reality (AR) to support complicated subterranean (sub-t) missions. Additionally, due to advances in wearable technology, the military will soon offer Soldiers the ability to wear AR head-mounted displays while conducting missions (Freedberg, 2019). Therefore, it is essential to understand how this technology will impact Soldiers’ spatial memory for sub-t environments. This paper describes the methods and preliminary results of in-progress work that uses VR and the Gardony Map Drawing Analyzer (Gardony et al., 2016) to analyze spatial memory following navigation in sub-t missions. Subjects completed a series of tasks in VR while utilizing simulated AR displays that provided navigation aid, such as a compass and an inertial navigation system (bird’s eye trace). After each mission, subjects sketched a diagram of the tunnel system they just explored. We use these sketches to measure how well subjects understood their environment and their recall and ability to recreate the environment for future intelligence purposes.

Albion Strawberry Responds to Mulch Treatments and Low Tunnels Covered with Photoselective Films

The impact of photoselective films on strawberry plants in a low tunnel system has not been well investigated in the northeastern United States, nor have there been studies looking at the effect of mulch color in a plasticulture system. During two separate years (2016 and 2017), we evaluated ‘Albion’ in an annual system with three ground mulch treatments (black plastic, white-on-black plastic, and no plastic) and under six cover treatments. Five of the cover treatments were low tunnel films that varied in their ultraviolet, photosynthetically active, and near-infrared radiation transmission profiles: Tufflite IVTM (TIV), KoolLite Plus (KLP), Trioplast (TRP), and custom-manufactured UV-transparent (UVT) and UV-blocking (UVO) films. The sixth cover treatment was the traditional open bed environment (no low tunnel). ‘Albion’ produced fruit for 18 to 19 continuous weeks during both years until as late as Thanksgiving (24 Nov.) in 2016. Overall, the average marketable yield was greater in 2017 (486 g/plant) than in 2016 (350 g/plant), and it was greater on black mulch than on no mulch (445 vs. 380 g/plant, respectively); white mulch was intermediate (419 g/plant) (P ≤ 0.05). There was not a significant increase in marketable yield under low tunnels compared with open beds. The average fruit mass was greater under KLP and UVO than open beds (TIV and UVT were intermediate), and greater on beds with no mulch than black mulch (white mulch was intermediate). Across cover treatments, plants on black mulch produced more runners than plants on white or no mulch, and the black mulch/open bed treatment generated the greatest number of runners in both years, more than double most other treatments in 2016. The present study demonstrates that mulch selection is important for maximizing the yield of ‘Albion’ in the Northeast region, and that both mulch and cover impact runnering and fruit size. For plant propagators producing ‘Albion’ tips in a field environment, the results of this study suggest they are likely to maximize runner quantity by cultivating plants on black mulch without low tunnel cover.