Graphics process unit accelerated lattice Boltzmann simulation of indoor air flow: Effects of sub-grid scale model in large-eddy simulation

In this present study, three-dimensional lattice Boltzmann method is implemented with the popular turbulence modeling method large-eddy simulation incorporating three different non-dynamic sub-grid scale models Smagorinsky, Vreman, and wall-adapting local eddy-viscosity for finding the inhomogeneous turbulent airflow patterns inside a model room with a partition. The large eddy simulation-lattice Boltzmann method code is validated with the experimental results of Posner’s model, where the model room having one partition at the bottom, one inlet, an outlet placed at top wall considered for the comparisons. The lattice Boltzmann method code is also validated without any sub-grid scale model with the results of lid-driven flow in a cubic cavity. The present numerical simulations are performed by the graphics process unit accelerated parallel programs using compute unified device architecture C platform. Double precession capable a Tesla k40 with 2880 compute unified device architecture cores NVIDIA graphics process unit card has been used for these simulations. Graphics processor units have gained popularity in recent years as a propitious platform for numerical simulation of fluid dynamics. In fact, faster computational task performance in graphics process units is one of the key factors for researchers to choose graphics process unit over conventional central processing units for the implementation of data-intensive numerical methods like lattice Boltzmann method. The effects of the sub-grid scale model have been evaluated in terms of the mean velocity profiles, streamlines as well as turbulence characteristics and found that there are significant differences in the results due to the different sub-grid scale models

Performance evaluation of damper control settings for operation of multiple-zone variable air volume reheat system in different building applications and climate types

Choosing the right control strategies is an important task for effective operation of variable air volume reheat (VAVR) system in commercial buildings. In this design, dampers’ position inside air terminal units (ATUs) are modulated to adjust the amount of air supply volume based on thermal zones’ cooling or heating demand. A minimum air flow fraction (MAFF) is set for damper settings of ATUs to avoid under-ventilation problem in thermal zones. This study investigated the impact of MAFF value on various performance aspects of multiple-zone VAVR design in different building applications and climate types. A five-storey commercial building for three applications of school, office and retail in four climate types of tropical monsoon, hot desert, Mediterranean and humid continental have been simulated in EnergyPlus building simulation software. The results of simulations have shown that lowering MAFF value in ATUs would reduce the required reheat coil energy to maintain precise air supply temperature at part load cooling scenarios. Nonetheless, this reduction could have some implications on thermal comfort and indoor air quality level of thermal zones in a multiple-zone arrangement. It was concluded that in general it is an energy efficient control strategy to keep MAFF value to as low as 0.1 for high ventilation rate spaces like classrooms in school buildings (except for hot desert climate). On the other hand, it is advisable to not reduce MAFF value below 0.3 for low ventilation rate spaces like office areas to avoid any air quality issues in thermal zones

A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)

Meeting abstrac

Clinicians' accounts of communication with patients in end-of-life care contexts: A systematic review.

ObjectiveCommunication between patients and end-of-life care providers requires sensitivity given the context and complexity involved. This systematic review uses a narrative approach to synthesise clinicians' understandings of communication in end-of-life care.MethodsA systematic, narrative synthesis approach was adopted given the heterogeneity across the 83 included studies. The review was registered prospectively on PROSPERO (ID: CRD42019125155). Medline was searched for all articles catalogued with the MeSH terms "palliative care," "terminal care" or "end-of-life care," and "communication". Articles were assessed for quality using a modified JQI-QARI tool.ResultsThe findings highlight the centrality and complexity of communication in end-of-life care. The challenges identified by clinicians in relation to such communication include the development of skills necessary, complexity of interpersonal interactions, and ways in which organisational factors impact upon communication. Clinicians are also aware of the need to develop strategies for interdisciplinary teams to improve communication.ConclusionTraining needs for effective communication in end-of-life contexts are not currently being met.Practice implicationsClinicians need more training to address the lack of skills to overcome interactional difficulties. Attention is also needed to address issues in the organisational contexts in which such communication occurs