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Developing safe proximity charts for impact moling and horizontal directional drilling operations
Published in Mark Knight, Neil Thomson, Underground Infrastructure Research, 2020
FLAC allows the inclusion of structural members within a soil mass. The structural member is classified according to its Young’s modulus, cross sectional area and second moment of area. In this case, pipelines were ‘attached’ to the mesh, facilitating soil-structure interaction. Information relating to the structural condition of the pipeline is available as a standard output of FLAC e.g. displacement, bending moment and axial strain. Hence, the predicted structural condition of a pipeline resulting from a cavity expansion of a certain diameter at a certain separation distance in specified soil conditions is available to the user.
Virtual Reality Interventions for Personal Development: A Meta-Analysis of Hardware and Software
Published in Human–Computer Interaction, 2019
VR interventions consist of two types of hardware—inputs and outputs (Burdea & Coiffet, 2003; Jayaram, Connacher, & Lyons, 1997). Input hardware receives user commands. Currently, the standard input hardware is the keyboard, mouse, and joystick, whereas specialized input hardware are sensor gloves, motion sensors, and other technologies (O’Flynn et al., 2013; Regterschot et al., 2014). Alternatively, output hardware presents relevant visual information. Currently, the standard output hardware is the computer monitor, whereas more advanced output hardware are head-mounted displays (HMDs), surround-screen displays, three-dimensional monitors, and other technologies (Hou, Nam, Peng, & Lee, 2012; Kihara et al., 2012). Both specialized input and output hardware have been suggested to improve the physical fidelity and immersive properties of a VR intervention, which could result in better outcomes (Burdea & Coiffet, 2003; Hou et al., 2012; Jayaram et al., 1997; Kihara et al., 2012; O’Flynn et al., 2013). The current article tests whether these specialized input and advanced output hardware provide better VR intervention outcomes than standard alternatives. In doing so, the results may indicate whether researchers and developers are allocating costly resources toward creating technologies with little benefits, and future research can identify the exact mechanisms that cause these outcomes.
Simulation and monetization of collateral airborne infection risk improvements from ultraviolet germicidal irradiation for coil maintenance
Published in Science and Technology for the Built Environment, 2018
Joseph Firrantello, William Bahnfleth
The value of ηUVGI depends on several parameters. Table 3 lists the design parameters and assumptions made in sizing coil UVGI systems for the 554 distinct air systems in the study buildings. UVGI surface and air irradiance calculations were performed using view factor methods developed by Kowalski (2003; analogous to those used by radiative heat transfer) and implemented with proprietary software. The value of k was set to 0.0002996 cm2/µJ, the median of species-averaged virus values tabulated by Kowalski (2003). Lamp output variation was modeled using Equation 8 (Lau et al. 2009) which applies to a typical hot cathode, standard output, cylindrical germicidal lamp in crossflow. The derating factor accounts for variation in output due to cooling (“wind chill”) as a function of air temperature and velocity. High output lamps are typically used in these applications, and purport to have more favorable derating characteristics versus standard output lamps for high air speeds and low temperatures. Equations developed for a high output, twin-tube lamp show similar behavior (Lau 2009) to Equation 8, but its geometry is not cylindrical, and a direct comparison cannot necessarily be made. In the absence of more specific lamp derating relations, Equation 8 may be considered conservative. where fUV is the UV output derating factor, Tair is the air temperature [°C], and Uair is the average airstream velocity [m/s].