Indoor mould growth prediction using coupled computational fluid dynamics and mould growth model

This study investigates, using in-situ and numerical simulation experiments, airflow and hygrothermal distribution in a mechanically ventilated academic research facility with known cases of microbial proliferations. Microclimate parameters were obtained from in-situ experiments and used as boundary conditions and validation of the numerical experiments with a commercial computational fluid dynamics (CFD) analysis tool using the standard k–ε model. Good agreements were obtained with less than 10% deviations between the measured and simulated results. Subsequent upon successful validation, the model was used to investigate hygrothermal and airflow profile within the shelves holding stored components in the facility. The predicted in-shelf hygrothermal profile was superimposed on mould growth limiting curve earlier documented in the literature. Results revealed the growth of xerophilic species in most parts of the shelves. The mould growth prediction was found in correlation with the microbial investigation in the case-studied room reported by the authors elsewhere. Satisfactory prediction of mould growth in the room successfully proved that the CFD simulation can be used to investigate the conditions that lead to microbial growth in the indoor environment

Optimally Controlled Field-Free Orientation of the Kicked Molecule

Efficient and long-lived field-free molecular orientation is achieved using only two kicks appropriately delayed in time. The understanding of the mechanism rests upon a molecular target state providing the best efficiency versus persistence compromise. An optimal control scheme is referred to for fixing the free parameters (amplitudes and the time delay between them). The limited number of kicks, the robustness and the transposability to different molecular systems advocate in favor of the process, when considering its experimental feasibility.Comment: 5 pages, 2 figures (version 2 contains some minor additions and corrects many misprints

Real time object customization in CAD system

Object customization in Computer Aided Design (CAD) is a method used to modify the sketch parameters and change the model geometries. This method is one of important features in part modelling which empowered CAD user to simply modify their product. The conventional method of modifying CAD model is usually relied on the manual editing. This paper outlines a development of program than can be integrated in CAD/CAM system for real time object customization. It uses Visual Basic (VB) programming with custom Graphical User Interface (GUI) generated in NX10 (CAD/CAM software) interface. The main contribution of this research is a tool for real time object customization that capable to assist the modification of 3D model. In order to develop the tool, 3D model modification instructions are translated into programming codes by using Journaling tools in NX interface. Editable parameters are identified based on the model shapes. The related codes are reconstructed, modified and linked to the functional GUI.  This allows user to simply modify the model shapes in real time with minimum process steps. The performance of the method is evaluated in terms of the reduction of process steps and time in modifying the 3D model in CAD system. All the findings and details of approach are presented

Approaches to Learning to Control Dynamic Uncertainty

In dynamic environments, when faced with a choice of which learning strategy to adopt, do people choose to mostly explore (maximizing their long term gains) or exploit (maximizing their short term gains)? More to the point, how does this choice of learning strategy influence one’s later ability to control the environment? In the present study, we explore whether people’s self-reported learning strategies and levels of arousal (i.e., surprise, stress) correspond to performance measures of controlling a Highly Uncertain or Moderately Uncertain dynamic environment. Generally, self-reports suggest a preference for exploring the environment to begin with. After which, those in the Highly Uncertain environment generally indicated they exploited more than those in the Moderately Uncertain environment; this difference did not impact on performance on later tests of people’s ability to control the dynamic environment. Levels of arousal were also differentially associated with the uncertainty of the environment. Going beyond behavioral data, our model of dynamic decision-making revealed that, in actual fact, there was no difference in exploitation levels between those in the highly uncertain or moderately uncertain environments, but there were differences based on sensitivity to negative reinforcement. We consider the implications of our findings with respect to learning and strategic approaches to controlling dynamic uncertainty.This study was supported by the Engineering and Physical Sciences Research Council

Comparative study ofthe computational fluid dynamics and fluid structure interaction analysis in human airways flow

Numerous studies have been done in order to get the most accurate result that represents the flow characteristics inside the human trachea. Numerical method was the most favorite type of study chosen to simulate the model due to the complexity of the geometry and difficulties to get the real trachea to do the experimental works. In this study, one actual healthy model of human trachea was reconstructed in order to compare, the different of the velocity and pressure distribution between two types of numerical modeling analysis: Computational Fluid Dynamics (CFD) and Fluid Structure Interaction (FSI) analysis. The model was extracted using the Computed Tomography (CT) scan images to maintain the realistic geometry. Velocity, 1.24 m/s was used at the inlet and the variations of the velocity and pressure distribution along the trachea were observed. The results shown that, the implementation of the FSI technique did produce different result and flexibility of the structure wall did influence the distribution of the velocity and pressure along the trachea

Simulation of lightning surges on tower transmission using PSCAD/EMTDC: a comparative study

This paper describes the analytical and the experimental responses of the surges strike on the transmission line towers. A new method of calculating transmission tower surge response has been proposed. It has been found that the tower surge response calculated by the proposed method has a close agreement with the measured tower surge response obtained from scale model and field tests. Without the use of simulation program, this topic might be difficult to understand. PSCAD/EMTDC has been selected as the software used to generate the appropriate data needed to graphically demonstrate this phenomenon

Does environmental knowledge moderate the relationship between household determinants' intention to practice solid waste segregation-at-source? a conceptual paper

Previous research has reported that environmental knowledge plays an important role in enhancing general pro-environmental behaviour, as environmental knowledge appears to be the key indicator for increasing awareness of several pollution promulgations and other natural environmental issues. However, the significant role of environmental knowledge in the intention of households to practise solid waste segregation-at-source is not well understood. This research will, therefore, investigate the influence of environmental knowledge on the intention of households to engage in solid waste segregation-at-source. Further analysis will also be carried out explore the moderating effect of environmental knowledge in the relationship between the households’ attitude and subjective norm (i.e. descriptive norm and injunctive norm) with the intention to practise solid waste segregation-at-source. The findings of this current research are expected to provide an essential opportunity to investigate knowledge gaps, to contribute to the enrichment of existing literature, as well as to provide important insights for local households and Malaysian government agencies to strengthen the sense of responsibility for environmental cleanliness

Practice implications of an antimicrobial stewardship intervention in a tertiary care teaching hospital, Qatar

Background: Antibiotic misuse is a worldwide public health problem and has been associated with increased morbidity, length of hospital stay, mortality, healthcare costs, and most importantly antibiotic resistance. Aims: We aimed to evaluate the compliance of antibiotic prescribing with national guidelines, assess how educational interventions can best be utilized to make impact and fill gaps for optimal antibiotic utilization, and to identify facilitators and barriers to implementing ASPs in Qatar. Methods: Six cross-sectional baseline audits of antibiotic prescribing were conducted over a two-week period at a tertiary care teaching hospital. A sub-analysis of prescriptions with follow up has followed. An educational intervention utilizing the PDSA (Plan-Do-Study-Act) tool was implemented to address gaps identified. A repeated audit was done to assess the impact of change. Lastly, interviews were conducted to recognize perceived facilitators and barriers for ASP implementation, identify strategies to overcome barriers, and evaluate the effectiveness of educational interventions. Results: The most common indication for antibiotic prescribing was febrile neutropenia (20.7%). The most frequently used class of antibiotics was carbapenems (21.4%). Sixty percent of prescriptions complied with guidelines. The rationale behind choosing not to adhere to guidelines was not documented in 37.2% of cases. Suboptimal documentation in records was targeted through our intervention. The audit post intervention showed slight improvement in documentation. Facilitators and barriers included: collaboration and communication among teams, compliance with guidelines, interventions documented by clinical pharmacists, and electronic system errors. Conclusions: Effective communication, continuous documentation in records, and repetitive education promote rational antibiotic prescribing and enhance ASPs.This report was made possible by a UREP award [UREP18-033-3-010] from the Qatar National Research Fund (a member of The Qatar Foundation)

Vanishing artifficial diffusion as a mechanism to accelerate convergence for multiphase porous media flow

Numerical solution of the equations governing multiphase porous media flow is challenging. A common approach to improve the performance of iterative non-linear solvers for these problems is to introduce artificial diffusion. Here, we present a mass conservative artificial diffusion that accelerates the non-linear solver but vanishes when the solution is converged. The vanishing artificial diffusion term is saturation dependent and is larger in regions of the solution domain where there are steep saturation gradients. The non-linear solver converges more slowly in these regions because of the highly non-linear nature of the solution. The new method provides accurate results while significantly reducing the number of iterations required by the non-linear solver. It is particularly valuable in reducing the computational cost of highly challenging numerical simulations, such as those where physical capillary pressure effects are dominant. Moreover, the method allows converged solutions to be obtained for Courant numbers that are at least two orders of magnitude larger than would otherwise be possible