Transient Cavity Dynamics and Divergence from the Stokes-Einstein Equation in Organic Aerosol

The diffusion of small molecules through viscous matrices formed by large organic molecules is important across a range of domains, including pharmaceutical science, materials chemistry, and atmospheric science, impacting on, for example, the formation of amorphous and crystalline phases. Here we report significant breakdowns in the Stokes–Einstein (SE) equation from measurements of the diffusion of water (spanning 5 decades) and viscosity (spanning 12 decades) in saccharide aerosol droplets. Molecular dynamics simulations show water diffusion is not continuous, but proceeds by discrete hops between transient cavities that arise and dissipate as a result of dynamical fluctuations within the saccharide lattice. The ratio of transient cavity volume to solvent volume increases with size of molecules making up the lattice, increasing divergence from SE predictions. This improved mechanistic understanding of diffusion in viscous matrices explains, for example, why organic compounds equilibrate according to SE predictions and water equilibrates more rapidly in aerosols

Transient reflection analysis to identify problems with a raw water pumping main

© 2008 ASCETransient analysis has been shown to have applications for the detection of discrete anomalies such as leakage, blockage and air pockets within pipelines. This technique may be extended to the investigation and assessment of the condition of pipelines. The issues associated with the field implementation of this technique, such as field measurement equipment, synchronization of measurements, lack of reliable system information, low pressures, the presence of air valves and operational issues also require further investigation. This paper presents the analysis of a raw water pumping main using field data collected during transient testing. This composite main of Acrylonitrile- Butadiene-Styrene (ABS) and Ductile Iron Cement Lined (DICL) pipe was designed to deliver 105 L/s and at the time of testing was capable of delivering only 87 L/s. Online and offline testing was undertaken with transients generated by the fast closure of a valve connected to the system via a standpipe. Both openings and closures of the valve were recorded, as were varying nozzle sizes. Online transients were also initiated by pump failures. A combination of transient and steady state analysis is used to determine the presence and location of anomalies within the pipeline with the aim to discover possible causes of the reduced flow capacity and assess the condition of the pipeline. An emphasis on the analysis of transient reflections, from system components and anomalies, is made including investigation of the consistency of results between openings and closures and varying nozzle sizes. The correspondence between reflection size and timing as measured at different locations is used to determine anomaly presence. Issues associated with applying this technique to a real world system are also investigated and discussed. Copyright ASCE 2006.Nicole S. Arbon, Martin F. Lambert, Angus R. Simpson, and Paul Memmlerhttp://www.eng.uc.edu/wdsa2006/WDSA2006_Program_Brochure%20(Final).pdfhttp://www.eng.uc.edu/wdsa2006

Development and Design of Energy Efficient Oil-Flooded Screw Compressors

It is estimated that about 17% of the world's generated power is used for compression. Thus all, even minor improvement of the efficiency of compressors will substantially reduce CO2 emission. This paper presents development of family of energy efficient oil-flooded screw compressors for Kirloskar Pneumatic Company Ltd. The developmental techniques adopted to improve efficiency such as introduction of superior 'N' rotor profile, rotor clearance management, performance calculation using 3D CCM (Computational Continuum Mechanics), direct parametric interface to CAD (Computer Aided Design), which contains bearing selection for complete 3D solid modelling. Also, contemporary prototyping and experimental investigation is supported by the fully computerised data acquisition and processing. The cumulative improvement of all these elements of the design process resulted in a very efficient machine which guarantees the competitive position of Kirloskar Pneumatic Company Limited in the screw compressor market

Effectiveness of a web-based intervention to prevent anxiety in the children of parents with anxiety:Protocol for a Randomized Controlled Trial

BACKGROUND: Anxiety is the most common childhood mental health condition and is associated with impaired child outcomes, including increased risk of mental health difficulties in adulthood. Anxiety runs in families: when a parent has anxiety, their child has a 50% higher chance of developing it themselves. Environmental factors are predominant in the intergenerational transmission of anxiety and, of these, parenting processes play a major role. Interventions that target parents to support them to limit the impact of any anxiogenic parenting behaviors are associated with reduced anxiety in their children. A brief UK-based group intervention delivered to parents within the UK National Health Service led to a 16% reduction in children meeting the criteria for an anxiety disorder. However, this intervention is not widely accessible. To widen access, a 9-module web-based version of this intervention has been developed. This course comprises psychoeducation and home practice delivered through text, video, animations, and practice tasks. OBJECTIVE: This study seeks to evaluate the feasibility of delivering this web-based intervention and assess its effectiveness in reducing child anxiety symptoms. METHODS:  This is the protocol for a randomized controlled trial (RCT) of a community sample of 1754 parents with self-identified high levels of anxiety with a child aged 2-11 years. Parents in the intervention arm will receive access to the web-based course, which they undertake at a self-determined rate. The control arm receives no intervention. Follow-up data collection is at months 6 and months 9-21. Intention-to-treat analysis will be conducted on outcomes including child anxiety, child mental health symptoms, and well-being; parental anxiety and well-being; and parenting behaviors. RESULTS: Funding was received in April 2020, and recruitment started in February 2021 and is projected to end in October 2022. A total of 1350 participants have been recruited as of May 2022. CONCLUSIONS: The results of this RCT will provide evidence on the utility of a web-based course in preventing intergenerational transmission of anxiety and increase the understanding of familial anxiety. TRIAL REGISTRATION: ClinicalTrials.gov NCT04755933; https://clinicaltrials.gov/ct2/show/NCT04755933 INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/4070

Interactive molecular dynamics in virtual reality from quantum chemistry to drug binding: An open-source multi-person framework

© 2019 Author(s). As molecular scientists have made progress in their ability to engineer nanoscale molecular structure, we face new challenges in our ability to engineer molecular dynamics (MD) and flexibility. Dynamics at the molecular scale differs from the familiar mechanics of everyday objects because it involves a complicated, highly correlated, and three-dimensional many-body dynamical choreography which is often nonintuitive even for highly trained researchers. We recently described how interactive molecular dynamics in virtual reality (iMD-VR) can help to meet this challenge, enabling researchers to manipulate real-time MD simulations of flexible structures in 3D. In this article, we outline various efforts to extend immersive technologies to the molecular sciences, and we introduce "Narupa," a flexible, open-source, multiperson iMD-VR software framework which enables groups of researchers to simultaneously cohabit real-time simulation environments to interactively visualize and manipulate the dynamics of molecular structures with atomic-level precision. We outline several application domains where iMD-VR is facilitating research, communication, and creative approaches within the molecular sciences, including training machines to learn potential energy functions, biomolecular conformational sampling, protein-ligand binding, reaction discovery using "on-the-fly" quantum chemistry, and transport dynamics in materials. We touch on iMD-VR's various cognitive and perceptual affordances and outline how these provide research insight for molecular systems. By synergistically combining human spatial reasoning and design insight with computational automation, technologies such as iMD-VR have the potential to improve our ability to understand, engineer, and communicate microscopic dynamical behavior, offering the potential to usher in a new paradigm for engineering molecules and nano-architectures