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https://www.readbyqxmd.com/read/29150933/design-of-a-novel-continuous-flow-reactor-for-low-ph-viral-inactivation
#1
Stephanie A Parker, Linus Amarikwa, Kevin Vehar, Raquel Orozco, Scott Godfrey, Jon Coffman, Parviz Shamlou, Cameron L Bardliving
Insufficient mixing in laminar flow reactors due to diffusion-dominated flow limits their use in applications where narrow residence time distribution (RTD) is required. The aim of this study was to design and characterize a laminar flow (Re 187.7-375.5) tubular reactor for low pH viral inactivation with enhanced radial mixing via the incorporation of curvature and flow inversions. Towards this aim, the reactor described here, Jig in a Box (JIB), was designed with a flow path consisting of alternating 270° degree turns...
November 18, 2017: Biotechnology and Bioengineering
https://www.readbyqxmd.com/read/29150346/aerodynamic-study-of-time-trial-helmets-in-cycling-racing-using-cfd-analysis
#2
F Beaumont, R Taiar, G Polidori, H Trenchard, F Grappe
The aerodynamic drag of three different time-trial cycling helmets was analyzed numerically for two different cyclist head positions. Computational Fluid Dynamics (CFD) methods were used to investigate the detailed airflow patterns around the cyclist for a constant velocity of 15 m/s without wind. The CFD simulations have focused on the aerodynamic drag effects in terms of wall shear stress maps and pressure coefficient distributions on the cyclist/helmet system. For a given head position, the helmet shape, by itself, obtained a weak effect on a cyclist's aerodynamic performance (<1...
November 8, 2017: Journal of Biomechanics
https://www.readbyqxmd.com/read/29145141/characterizing-pollutant-emissions-from-mosquito-repellents-incenses-and-implications-in-risk-assessment-of-human-health
#3
Lina Wang, Xinran Zheng, Svetlana Stevanovic, Zhiyuan Xiang, Jing Liu, Huiwen Shi, Jing Liu, Mingzhou Yu, Chun Zhu
Mosquito-repellent incense is one of the most popular products used for dispelling mosquitos during summer in China. It releases large amounts of particulate and gaseous pollutants which constitute a potential hazard to human health. We conducted chamber experiment to characterize major pollutants from three types of mosquito-repellent incenses, further assessed the size-fractionated deposition in human respiratory system, and evaluated the indoor removing efficiency by fresh air. Results showed that the released pollutant concentrations were greater than permissible levels in regulations in GB3095-2012, as well as suggested by the World Health Organization (WHO)...
October 22, 2017: Chemosphere
https://www.readbyqxmd.com/read/29137742/ultrasound-coupled-with-supercritical-carbon-dioxide-for-exfoliation-of-graphene-simulation-and-experiment
#4
Yanzhe Gai, Wucong Wang, Ding Xiao, Yaping Zhao
Ultrasound coupled with supercritical CO2 has become an important method for exfoliation of graphene, but behind which a peeling mechanism is unclear. In this work, CFD simulation and experiment were both investigated to elucidate the mechanism and the effects of the process parameters on the exfoliation yield. The experiments and the CFD simulation were conducted under pressure ranging from 8MPa to 16MPa, the ultrasonic power ranging from 12W to 240W and the frequency of 20kHz. The numerical analysis of fluid flow patterns and pressure distributions revealed that the fluid shear stress and the periodical pressure fluctuation generated by ultrasound were primary factors in exfoliating graphene...
March 2018: Ultrasonics Sonochemistry
https://www.readbyqxmd.com/read/29132119/how-tall-buildings-affect-turbulent-air-flows-and-dispersion-of-pollution-within-a-neighbourhood
#5
Elsa Aristodemou, Luz Maria Boganegra, Laetitia Mottet, Dimitrios Pavlidis, Achilleas Constantinou, Christopher Pain, Alan Robins, Helen ApSimon
The city of London, UK, has seen in recent years an increase in the number of high-rise/multi-storey buildings ("skyscrapers") with roof heights reaching 150 m and more, with the Shard being a prime example with a height of ∼310 m. This changing cityscape together with recent plans of local authorities of introducing Combined Heat and Power Plant (CHP) led to a detailed study in which CFD and wind tunnel studies were carried out to assess the effect of such high-rise buildings on the dispersion of air pollution in their vicinity...
November 10, 2017: Environmental Pollution
https://www.readbyqxmd.com/read/29125413/a-computational-fluid-dynamics-simulation-framework-for-ventricular-catheter-design-optimization
#6
Sofy H Weisenberg, Stephanie C TerMaath, Charlotte N Barbier, Judith C Hill, James A Killeffer
OBJECTIVE Cerebrospinal fluid (CSF) shunts are the primary treatment for patients suffering from hydrocephalus. While proven effective in symptom relief, these shunt systems are plagued by high failure rates and often require repeated revision surgeries to replace malfunctioning components. One of the leading causes of CSF shunt failure is obstruction of the ventricular catheter by aggregations of cells, proteins, blood clots, or fronds of choroid plexus that occlude the catheter's small inlet holes or even the full internal catheter lumen...
November 10, 2017: Journal of Neurosurgery
https://www.readbyqxmd.com/read/29124548/development-of-an-experimental-and-digital-cardiovascular-arterial-model-for-transient-hemodynamic-and-postural-change-studies-a-preliminary-framework-analysis
#7
Rodward L Hewlin, John P Kizito
The ultimate goal of the present work is to aid in the development of tools to assist in the treatment of cardiovascular disease. Gaining an understanding of hemodynamic parameters for medical implants allow clinicians to have some patient-specific proposals for intervention planning. In the present work an experimental and digital computational fluid dynamics (CFD) arterial model consisting of a number of major arteries (aorta, carotid bifurcation, cranial, femoral, jejunal, and subclavian arteries) were fabricated to study: (1) the effects of local hemodynamics (flow parameters) on global hemodynamics (2) the effects of transition from bedrest to upright position (postural change) on hemodynamics, and (3) diffusion of dye (medical drug diffusion simulation) in the arterial system via experimental and numerical techniques...
November 9, 2017: Cardiovascular Engineering and Technology
https://www.readbyqxmd.com/read/29121067/high-yields-of-hydrogen-production-from-methanol-steam-reforming-with-a-cross-u-type-reactor
#8
Shubin Zhang, Yufeng Zhang, Junyu Chen, Xuelin Zhang, Xiaowei Liu
This paper presents a numerical and experimental study on the performance of a methanol steam reformer integrated with a hydrogen/air combustion reactor for hydrogen production. A CFD-based 3D model with mass and momentum transport and temperature characteristics is established. The simulation results show that better performance is achieved in the cross-U type reactor compared to either a tubular reactor or a parallel-U type reactor because of more effective heat transfer characteristics. Furthermore, Cu-based micro reformers of both cross-U and parallel-U type reactors are designed, fabricated and tested for experimental validation...
2017: PloS One
https://www.readbyqxmd.com/read/29118115/computational-tools-for-clinical-support-a-multi-scale-compliant-model-for-haemodynamic-simulations-in-an-aortic-dissection-based-on-multi-modal-imaging-data
#9
Mirko Bonfanti, Stavroula Balabani, John P Greenwood, Sapna Puppala, Shervanthi Homer-Vanniasinkam, Vanessa Díaz-Zuccarini
Aortic dissection (AD) is a vascular condition with high morbidity and mortality rates. Computational fluid dynamics (CFD) can provide insight into the progression of AD and aid clinical decisions; however, oversimplified modelling assumptions and high computational cost compromise the accuracy of the information and impede clinical translation. To overcome these limitations, a patient-specific CFD multi-scale approach coupled to Windkessel boundary conditions and accounting for wall compliance was developed and used to study a patient with AD...
November 2017: Journal of the Royal Society, Interface
https://www.readbyqxmd.com/read/29117514/investigating-cascade-impactor-performance-using-a-modified-3d-printed-induction-port
#10
Kai Berkenfeld, Michael Bernauer, Jason T McConville, Alf Lamprecht
Based on a computer tomographic scan of a human trachea, a modified induction port (mIP), for use with the Next Generation Cascade Impactor, was manufactured using 3D printing technology. Standard United States Pharmacopoeia IP (USPIP) was compared to the mIP and a 3D printed version of the USPIP (USP3DIP) by analyzing different types of commercial salbutamol formulations for inhalation. Increased retention of particles in the mIP was found analyzing a pMDI formulation, leading to a decrease in the FPF from 28...
November 5, 2017: International Journal of Pharmaceutics
https://www.readbyqxmd.com/read/29109823/numerical-study-of-hydrodynamic-forces-for-afm-operations-in-liquid
#11
Tobias Berthold, Guenther Benstetter, Werner Frammelsberger, Rosana Rodríguez, Montserrat Nafría
For advanced atomic force microscopy (AFM) investigation of chemical surface modifications or very soft organic sample surfaces, the AFM probe tip needs to be operated in a liquid environment because any attractive or repulsive forces influenced by the measurement environment could obscure molecular forces. Due to fluid properties, the mechanical behavior of the AFM cantilever is influenced by the hydrodynamic drag force due to viscous friction with the liquid. This study provides a numerical model based on computational fluid dynamics (CFD) and investigates the hydrodynamic drag forces for different cantilever geometries and varying fluid conditions for Peakforce Tapping (PFT) in liquids...
2017: Scanning
https://www.readbyqxmd.com/read/29107725/proximal-stenosis-is-associated-with-rupture-status-in-middle-cerebral-artery-aneurysms
#12
Alexei Antonov, Kenichi Kono, Kilian Greim-Kuczewski, James E Hippelheuser, Alexandra Lauric, Adel M Malek
BACKGROUND: Hemodynamic factors impact cerebral aneurysm development and progression. Parent vessel architectural features, such as caliber, curvature and angle can affect downstream pressure and shear stress. OBJECTIVE: Investigate the association between proximal parent vessel stenosis and aneurysm rupture status at the middle cerebral artery (MCA) bifurcation. METHODS: Catheter 3D rotational angiographic datasets from 69 Japanese patients with MCA aneurysms (58 unruptured/11 ruptured) were analyzed...
October 28, 2017: World Neurosurgery
https://www.readbyqxmd.com/read/29107636/impact-of-side-branches-on-the-computation-of-fractional-flow-in-intracranial-arterial-stenosis-using-the-computational-fluid-dynamics-method
#13
Haipeng Liu, Linfang Lan, Xinyi Leng, Hing Lung Ip, Thomas W H Leung, Defeng Wang, Ka Sing Wong
BACKGROUND: Computational fluid dynamics (CFD) allows noninvasive fractional flow (FF) computation in intracranial arterial stenosis. Removal of small artery branches is necessary in CFD simulation. The consequent effects on FF value needs to be judged. METHODS: An idealized vascular model was built with 70% focal luminal stenosis. A branch with one third or one half of the radius of the parent vessel was added at a distance of 5, 10, 15 and 20 mm to the lesion...
October 27, 2017: Journal of Stroke and Cerebrovascular Diseases: the Official Journal of National Stroke Association
https://www.readbyqxmd.com/read/29104265/design-and-electro-thermo-mechanical-behavior-analysis-of-au-si%C3%A2-n%C3%A2-bimorph-microcantilevers-for-static-mode-sensing
#14
Seok-Won Kang, Joe Fragala, Su-Ho Kim, Debjyoti Banerjee
This paper presents a design optimization method based on theoretical analysis and numerical calculations, using a commercial multi-physics solver (e.g., ANSYS and ESI CFD-ACE+), for a 3D continuous model, to analyze the bending characteristics of an electrically heated bimorph microcantilever. The results from the theoretical calculation and numerical analysis are compared with those measured using a CCD camera and magnification lenses for a chip level microcantilever array fabricated in this study. The bimorph microcantilevers are thermally actuated by joule heating generated by a 0...
November 1, 2017: Sensors
https://www.readbyqxmd.com/read/29092476/cfd-analysis-of-laboratory-scale-phase-equilibrium-cell-operation
#15
Mohamed Ali Jama, Kaj Nikiforow, Muhammad Saad Qureshi, Ville Alopaeus
For the modeling of multiphase chemical reactors or separation processes, it is essential to predict accurately chemical equilibrium data, such as vapor-liquid or liquid-liquid equilibria [M. Šoóš et al., Chem. Eng. PROCESS: Process Intensif. 42(4), 273-284 (2003)]. The instruments used in these experiments are typically designed based on previous experiences, and their operation verified based on known equilibria of standard components. However, mass transfer limitations with different chemical systems may be very different, potentially falsifying the measured equilibrium compositions...
October 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/29089109/explosive-lower-limb-extension-mechanics-an-on-land-vs-in-water-exploratory-comparison
#16
Brice Guignard, Jessy Lauer, Pierre Samozino, Luis Mourão, João Paulo Vilas-Boas, Annie Hélène Rouard
During a horizontal underwater push-off, performance is strongly limited by the presence of water, inducing resistances due to its dense and viscous nature. At the same time, aquatic environments offer a support to the swimmer with the hydrostatic buoyancy counteracting the effects of gravity. Squat jump is a vertical terrestrial push-off with a maximal lower limb extension limited by the gravity force, which attracts the body to the ground. Following this observation, we characterized the effects of environment (water vs...
October 25, 2017: Journal of Biomechanics
https://www.readbyqxmd.com/read/29079097/assessing-the-relationship-between-movement-and-airflow-in-the-upper-airway-using-computational-fluid-dynamics-with-motion-determined-from-magnetic-resonance-imaging
#17
Alister J Bates, Andreas Schuh, Gabriel Amine-Eddine, Keith McConnell, Wolfgang Loew, Robert J Fleck, Jason C Woods, Charles L Dumoulin, Raouf S Amin
BACKGROUND: Computational fluid dynamics simulations of respiratory airflow in the upper airway reveal clinically relevant information, including sites of local resistance, inhaled particle deposition, and the effect of pathological constrictions. Unlike previous simulations, which have been performed on rigid anatomical models from static medical imaging, this work utilises ciné imaging during respiration to create dynamic models and more closely represent airway physiology. METHODS: Airway movement maps were obtained from non-rigid image registration of fast-cine MRI and applied to high-spatial-resolution airway surface models...
October 14, 2017: Clinical Biomechanics
https://www.readbyqxmd.com/read/29076944/a-numerical-simulation-of-heartassist5-blood-pump-using-an-advanced-turbulence-model
#18
Primož Drešar, Marcel C M Rutten, Igor D Gregorič, Jožef Duhovnik
The need for mechanical assistance of the failing heart has increased with improvements in medicine and a rapidly aging population. In recent decades, significant progress has been made in the development and refinement of ventricular assist devices (VADs). Such devices operate in mixed laminar, transitional, and turbulent flow regime. One tool that assists in the development of VADs by facilitating understanding of the physical and mechanical properties of these flow regimes is computational fluid dynamics (CFD)...
October 23, 2017: ASAIO Journal: a Peer-reviewed Journal of the American Society for Artificial Internal Organs
https://www.readbyqxmd.com/read/29068595/computational-fluid-dynamics-in-the-assessment-of-patients-postoperative-status-after-glottis-widening-surgery
#19
Magdalena Marków, Daniel Janecki, Bogusława Orecka, Maciej Misiołek, Krzysztof Warmuziński
BACKGROUND: Computational fluid dynamics (CFD), a rapidly developing instrument with a number of practical applications, allows calculation and visualization of the changing parameters of airflow in the upper respiratory tract. OBJECTIVES: The aim of this study was to demonstrate the advantages of CFD as an instrument for noninvasive tests of the larynx in patients who had undergone surgical treatment due to bilateral vocal fold paralysis. MATERIAL AND METHODS: Surface measurements of the glottic space were made during maximum adduction of the vocal folds...
September 2017: Advances in Clinical and Experimental Medicine: Official Organ Wroclaw Medical University
https://www.readbyqxmd.com/read/29068327/how-well-mixed-is-well-mixed-hydrodynamic-biokinetic-model-integration-in-an-aerated-tank-of-a-full-scale-water-resource-recovery-facility
#20
Usman Rehman, Wim Audenaert, Youri Amerlinck, Thomas Maere, Marina Arnaldos, Ingmar Nopens
Current water resource recovery facility (WRRF) models only consider local concentration variations caused by inadequate mixing to a very limited extent, which often leads to a need for (rigorous) calibration. The main objective of this study is to visualize local impacts of mixing by developing an integrated hydrodynamic-biokinetic model for an aeration compartment of a full-scale WRRF. Such a model is able to predict local variations in concentrations and thus allows judging their importance at a process level...
October 2017: Water Science and Technology: a Journal of the International Association on Water Pollution Research
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