Hardware Acceleration of High-Performance Computational Flow Dynamics Using High-Bandwidth Memory-Enabled Field-Programmable Gate Arrays

Scientific computing is at the core of many High-Performance Computing applications, including computational flow dynamics. Because of the utmost importance to simulate increasingly larger computational models, hardware acceleration is receiving increased attention due to its potential to maximize the performance of scientific computing. Field-Programmable Gate Arrays could accelerate scientific computing because of the possibility to fully customize the memory hierarchy important in irregular applications such as iterative linear solvers. In this article, we study the potential of using Field-Programmable Gate Arrays in High-Performance Computing because of the rapid advances in reconfigurable hardware, such as the increase in on-chip memory size, increasing number of logic cells, and the integration of High-Bandwidth Memories on board. To perform this study, we propose a novel Sparse Matrix-Vector multiplication unit and an ILU0 preconditioner tightly integrated with a BiCGStab solver kernel. We integrate the developed preconditioned iterative solver in Flow from the Open Porous Media project, a state-of-the-art open source reservoir simulator. Finally, we perform a thorough evaluation of the FPGA solver kernel in both stand-alone mode and integrated in the reservoir simulator, using the NORNE field, a real-world case reservoir model using a grid with more than 10 5 cells and using three unknowns per cell.

Development and Patient Experience Evaluation of a Gentle Atomizer for Nasal Drug Delivery

Background: Recently, nasal drug delivery has emerged as a convenient modality for the treatment of multiple, allergic, infectious, and inflammatory sinonasal conditions. Some patients report discomfort and irritation associated with the pressure and flow generated by using typical atomizers which may lead to decrease patient compliance and lower satisfaction. We sought to develop a rather gentle atomizer for nasal irrigation that would ameliorate the discomfort associated with nasal drug delivery. Herein, we report the development of an atomizer via fluid dynamics modeling and evaluating the patient experience.Methods: Using computational flow dynamics modeling, we assessed the distribution of atomized droplets to compare the conventional narrow-angle (NA) Vs a new open-angle swirling effect (OSE) atomizer. The goal for the new atomizer was to generate a swirling effect by opening a spray cone from a tapered nozzle bottle at different head tilted positions to determine the most efficient one that would enhance drug delivery and aid in patient comfort. Once the best computational model was generated and the atomizer developed, a group of 13 healthy volunteers consented to participate in the performance evaluation of the two atomizers (NA and OSE). Participants gauged both atomizers for ergonomics, pressure, and comfort for drug delivery (saline). The participants' feedback was collected using the nozzle tip sensory attributes questionnaire.Results: Atomizer Fluid Dynamics: The comparison was made between NA and OSE using the latest recommendation on the intranasal delivery angle of 45º with the nozzle 1.5 cm into the nose bypassing the nasal valve. The NA went 7cm into the nose, and hence generated high frictional pressure in the nasal mucosa. On the other hand, the OSE deliverd doses between 3 - 7 cm, thus generating less pressure. Patient Experience: 60% of the participants encountered irritation with the NA atomizer such as pain and a burning sensation. About 20% felt the OSE to be soft and pleasant, while 90% reported a misting sensation.Conclusion: The results of the present study suggest that OSE is a viable and more comfortable system to deliver intranasal therapies. These findings shed light on our understanding of the fluid flow dynamics to design extra efficient and comfortable atomizers to maximize drug delivery in the nasal cavity and potentially increase patient satisfaction as well as compliance.

Fundamental Studies of Rapidly Fabricated On-Chip Passive Micromixer for Modular Microfluidics

Micromixers play an important role in many modular microfluidics. Complex on-chip mixing units and smooth channel surfaces ablated by lasers on polymers are well-known problems for microfluidic chip fabricating techniques. However, little is known about the ablation of rugged surfaces on polymer chips for mixing uses. This paper provides the first report of an on-chip compact micromixer simply, easily and quickly fabricated using laser-ablated irregular microspheric surfaces on a polymethyl methacrylate (PMMA) microfluidic chip for continuous mixing uses in modular microfluidics. The straight line channel geometry is designed for sequential mixing of nanoliter fluids in about 1 s. The results verify that up to about 90% of fluids can be mixed in a channel only 500 µm long, 200 µm wide and 150 µm deep using the developed micromixer fabricating method under optimized conditions. The computational flow dynamics simulation and experimental result agree well with each other.

Investigation on the Thermal Condition of a Traditional Cold-Lane in Summer in Subtropical Humid Climate Region of China

A Chinese traditional narrow street, named Cold-Lane, can create a microclimatic zone that provides pedestrian thermal comfort under hot and humid climate conditions. This phenomenon was observed through experimental measurement during the summer of 2016. The heat transfer rate over the pedestrian body surface was calculated to reveal why pedestrians experience a cool sensation, and computational flow dynamics (CFD) simulation was carried out to study the influence of the street aspect ratio on the shading effect. It was found that the perception of thermal comfort can be attributed mainly to the radiation between the relatively cool surrounding walls and the human body, and the wind velocity has little effect on sensible heat dissipation. The cool horizontal and vertical surfaces in the street canyon are mainly due to the shading effect as a result of the small aspect ratio, which is a typical characteristic of the traditional Chinese street. The shading effect of the high walls on both sides creates the cooling effect of this narrow street.

From Early Morphometrics to Machine Learning—What Future for Cardiovascular Imaging of the Pulmonary Circulation?

Imaging plays a cardinal role in the diagnosis and management of diseases of the pulmonary circulation. Behind the picture itself, every digital image contains a wealth of quantitative data, which are hardly analysed in current routine clinical practice and this is now being transformed by radiomics. Mathematical analyses of these data using novel techniques, such as vascular morphometry (including vascular tortuosity and vascular volumes), blood flow imaging (including quantitative lung perfusion and computational flow dynamics), and artificial intelligence, are opening a window on the complex pathophysiology and structure–function relationships of pulmonary vascular diseases. They have the potential to make dramatic alterations to how clinicians investigate the pulmonary circulation, with the consequences of more rapid diagnosis and a reduction in the need for invasive procedures in the future. Applied to multimodality imaging, they can provide new information to improve disease characterization and increase diagnostic accuracy. These new technologies may be used as sophisticated biomarkers for risk prediction modelling of prognosis and for optimising the long-term management of pulmonary circulatory diseases. These innovative techniques will require evaluation in clinical trials and may in themselves serve as successful surrogate end points in trials in the years to come.

Identification of cord sources in glass using CFD

Cord appearance in the glass industry is a serious problem in high glass quality tableware production. The increased frequency of sharp cords provoked a serious analysis on cord origin and their elimination at the production line. Optical microscopy and electron microprobe analysis (EMA) were applied as direct methods for cord identification. A computational flow dynamics calculation (CFD) and process data analysis were used to verify the hypothesised source of the inhomogeneity. The hypothesis on origin of ZrO2 free cords containing high amounts of Al2O3 was postulated in relation to the refractory material composition of the forehearth. Calculations showed that the suggested mechanism at temperatures between 1200 and 1300°C was relevant. The hypothesis was supported by a change of chemical character of the cords after partial removal of the poorly resistant material. Also the average cord frequency was reduced on a production line from 53 to 17%. CFD simulations indicated that there may exist an effective mixing strategy on cord dissolution. Increasing stirrer rotation speed in a tempering part of the forehearth had a positive effect on cord disruption. The proposed stirrer set up decreased the cord frequency to less than 2%.

Diagnostic accuracy of two-dimensional coronary angiographic derived fractional flow reserve

Background Non-invasive fractional flow reserve (NiFFR) is an emerging method for evaluating the functional significance of a coronary lesion during diagnostic coronary angiography (CAG). The method relies on the computational flow dynamics and the 3D reconstruction of the vessel extracted from CAG. In the present study, we sought to evaluate the diagnostic performance and applicability of 2D-based NiFFR. Methods In this prospective observational study, we evaluated 2D-based NiFFR in 279 candidates for invasive CAG and invasive FFR. NiFFR was calculated via 2 methods: variable NiFFR, in which the contrast transport time was extracted from the angiographic view, and fixed NiFFR, in which a prespecified frame count was applied. Results The final analysis was performed on 245 patients (250 lesions). Variable NiFFR had an area under the receiver operating characteristic curve of 81.5%, an accuracy of 80.0%, a sensitivity of 82.2%, a specificity of 82.2%, a negative predictive value of 91.4%, and a positive predictive value of 63.6%. The mean difference between FFR and NiFFR was −0.0244 ±0.0616 (P≤0.0001). A pressure wire-free hybrid strategy was possible in 68.8% of our population with variable NiFFR. Conclusions Our 2D-based NiFFR yielded results comparable to those derived from 3D-based software. Our findings should, however, be confirmed in larger trials. Pressure wire-free hybrid strategy Funding Acknowledgement Type of funding source: None