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Heat and mass transfer are important processes associated with wildland fire. Both radiant and convective heat transfer are important processes with convection often being the dominant mechanism. Unlike radiation, there is no direct method of measuring convection. Since convective heat transfer is governed by the fluid flow, understanding the fluid flow provides good understanding on the convective heat transfer. In fluid mechanics, flow visualization is a common methodology used to understand flow characteristics. Schlieren imagery is a common flow visualization technique which captures changes in fluid density such as the ones occur around a fire. Background-Oriented Schlieren (BOS) is a flow visualization technique that uses a background image with various patterns to visualize the density gradient caused by density fluctuations in a fluid. We applied BOS to measure the flow associated with laboratory-scale line fires. The reproducible fires were spreading in pine needle fuel beds in a wind tunnel with and without imposed wind. This initial application of BOS in a fire environment successfully visualized the flow around the flame. The visualized flow underwent a secondary process to produce the velocity field of the flow. Results indicate that even in conditions where the fire is known to be dominated by radiation, wind carried the thermal plume ahead of the flame front and expanded the thermal plume. In contrast, in the no wind condition, the thermal plume remained vertical above the fire. Using the BOS imagery, a new model for estimation of convective heat transfer was introduced. In addition to estimation of the convective heat transfer ahead of the fire, this new model enables visualization of convective motion.

Stirred suspension culture is becoming a popular method for expanding human pluripotent stem cells (hPSCs). While stirring generates adequate fluid motions to lift the cells and facilitates mass transfers (of nutrients, dissolved gases, and metabolic wastes), excessive stirring could impose hydrodynamic forces deleterious for the growth of the cells. In this study, computational fluid dynamics (CFD) simulations were performed to first investigate hydrodynamic characteristics of fluid flows in a spinner flask, a common stirred suspension culture vessel used in laboratories. Flow patterns and distributions of shear stresses and the Kolmogorov length scales at varying impeller speeds were obtained. Comparison of the Kolmogorov length scales and sizes of hPSC aggregates, measured in the authors’ previous experimental study, showed a strong correlation between the two. In addition to the spinner flask which generated complex and transient turbulent flows, this study investigated a newly developed rotary wall vessel that had been designed to produce laminar, circular Couette flows in order to control shear stress. CFD simulations revealed significantly more uniform and homogeneous flows compared to those in the spinner flask, suggesting that the rotary wall vessel is a suitable culture vessel to investigate roles of shear stress on hPSCs in suspension.

Smoke from human-induced fires such as prescribed fires can occasionally cause significant reduction in visibility on highways in the southern United States. Visibility reduction to less than 3 m has been termed “superfog” and environmental conditions that lead to its formation have been proposed previously. Accurate characterization and prediction of precursor conditions for superfog is needed to prevent dangerous low visibility situations when planning prescribed fires. It is hypothesized that extremely hygroscopic cloud condensation nuclei from the smoldering phase of a fire can produce a large number of droplets smaller in size than in naturally occurring fog. This large number of small droplets can produce superfog conditions with relatively low liquid water content. A thermodynamics-based model for fog formation was developed. Laboratory generated superfog measured by a Phase Doppler Particle Analyzer determined that mean droplet radius was 1.5 μm and the size distribution could be modeled with a lognormal distribution. Experiments in an environmentally-conditioned wind tunnel using longleaf pine (Pinus palustris Mill.) needle fuel beds provided visibility, heat flux, temperature, humidity, and particle data for model validation. Numerical modeling was used to approximate the growth of a superfog boundary-layer with liquid water content values of 2 g m−3 or greater. The model successfully predicted previous superfog events.

Both steady and unsteady Reynolds Averaged Navier-Stokes (RANS) techniques coupled with the k-ε and k-ω(SST) turbulence models are utilized to study the flow characteristics and hot gas ingestion through rim seal in a subscale 1.5-stage axial gas turbine. A scalar transport equation is solved for a tracer gas to represent the coolant flow interaction with the main stream flow. To validate the numerical methodology, radial pressure and sealing effectiveness distributions are compared with the experimental data. The k-ω(SST) turbulence model has the capability to predict secondary flow characteristics, reattachment and separation, thus leading to better agreement with the experimental data. Both radial and circumferential pressure distributions are analyzed to get deeper insight into rotationally and externally induced ingress mechanisms. The circumferential pressure peak-to-trough amplitude is significantly attenuated in the cavity region compared to annulus region. Finally, different purge flow rates and rotational speeds are examined. Results indicate that as purge flow rate increases, the static pressure in the disk cavity region raises remarkably and consequently the sealing effectiveness improves. Averaged sealing effectiveness in the rim cavity decreases linearly with the rotational speed. To visualize different mechanisms of ingestion, streamline and flow field are shown.

Approximately 3 billion individuals rely on solid fuels for cooking globally. For a large portion of these – an estimated 533 million – cooking is outdoors, where emissions from cookstoves pose a health risk to both cooks and other household and village members. Models that estimate emissions rates from stoves in indoor environments that would meet WHO air quality guidelines (AQG), explicitly don't account for outdoor cooking. The objectives of this paper are to link health based exposure guidelines with emissions from outdoor cookstoves, using a Monte Carlo simulation of cooking times from Haryana India coupled with inverse Gaussian dispersion models. Mean emission rates for outdoor cooking that would result in incremental increases in personal exposure equivalent to the WHO AQG during a 24-h period were 126 ± 13 mg/min for cooking while squatting and 99 ± 10 mg/min while standing. Emission rates modeled for outdoor cooking are substantially higher than emission rates for indoor cooking to meet AQG, because the models estimate impact of emissions on personal exposure concentrations rather than microenvironment concentrations, and because the smoke disperses more readily outdoors compared to indoor environments. As a result, many more stoves including the best performing solid-fuel biomass stoves would meet AQG when cooking outdoors, but may also result in substantial localized neighborhood pollution depending on housing density. Inclusion of the neighborhood impact of pollution should be addressed more formally both in guidelines on emissions rates from stoves that would be protective of health, and also in wider health impact evaluation efforts and burden of disease estimates. Emissions guidelines should better represent the different contexts in which stoves are being used, especially because in these contexts the best performing solid fuel stoves have the potential to provide significant benefits.

Chemical reactors, air lubrication systems, and the aeration of the oceans rely, either in part or in whole, on the interaction of bubbles and their surrounding liquid. Even though bubbly mixtures have been studied at both the macroscopic and bubble level, the dissipation field associated with an individual bubble in a shear flow has not been thoroughly investigated. Exploring the nature of this phenomenon is critical not only when examining the effect a bubble has on the dissipation in a bulk shear flow but also when a microbubble interacts with turbulent eddies near the Kolmogorov length scale. In order to further our understanding of this behavior, this study investigated these interactions both analytically and experimentally. From an analytical perspective, expressions were developed to model the dissipation associated with the creeping flow fields in and around a fluid particle immersed in a linear shear flow. Experimentally, tests were conducted using a simple test setup that corroborated the general findings of the theoretical investigation. Both the analytical and experimental results indicate that the presence of bubbles in a shear flow causes elevated dissipation of kinetic energy.

The current study evaluates the influence of roadside solid and vegetation barriers on the near-road air quality. Reynolds Averaged Navier-Stokes (RANS) technique coupled with the k−ε realizable turbulence model is utilized to investigate the flow pattern and pollutant concentration. A scalar transport equation is solved for a tracer gas to represent the roadway pollutant emissions. In addition, a broad range of turbulent Schmidt numbers are tested to calibrate the scalar transport equation. Three main scenarios including flat terrain, solid barrier, and vegetative barrier are studied. To validate numerical methodology, predicted pollutant concentration is compared with published wind tunnel data. Results show that the solid barrier induces an updraft motion and lofts the vehicle emission plume. Therefore, the ground-level pollutant concentration decreases compared to the flat terrain. For the vegetation barrier, different sub-scenarios with different vegetation densities ranging from approximately flat terrain to nearly solid barrier are examined. Dense canopies act in a similar manner as a solid barrier and mitigate the pollutant concentration through vertical mixing. On the other hand, the high porosity vegetation barriers reduce the wind speed and lead to a higher pollutant concentration. As the vegetation density increases, i.e. the barrier porosity decreases, the recirculation zone behind the canopy becomes larger and moves toward the canopy. The dense plant canopy with LAD=3.33m−2m3 can improve the near-road air quality by 10% and high porosity canopy with LAD=1m−2m3 deteriorates near-road air quality by 15%. The results of this study can be implemented as green infrastructure design strategies by urban planners and forestry organizations.

The interaction of converging fires often leads to significant changes in fire behavior, including increased flame length, angle, and intensity. In this paper, the fluid mechanics of two adjacent line fires are studied both theoretically and experimentally. A simple potential flow model is used to explain the tilting of interacting flames towards each other, which results from a momentum imbalance triggered by fire geometry. The model was validated by measuring the velocity field surrounding stationary alcohol pool fires. The flow field was seeded with high-contrast colored smoke, and the motion of smoke structures was analyzed using a cross-correlation optical flow technique. The measured velocities and flame angles are found to compare reasonably with the predicted values, and an analogy between merging fires and wind-blown flames is proposed.

With the passage of California Senate Bill 375, which motivates infill development near transit hubs, there is the potential to increase vehicle congestion in residential communities and increase in human exposure to toxic mobile source pollutants. Among all the mitigation strategies that protect near roadway residents from health-affecting vehicular emissions (e.g. separating sensitive receptors from high traffic roadways), this paper discusses the impact of sound wall barriers (SBs) in reducing the air pollution exposure of nearby residents. To date, there have been some studies done to understand the impact of these structures on dispersion of vehicular emissions; however, no definitive conclusion has been drawn yet. The main objective of this paper is to provide more information and details on flow and dispersion affected by barriers through a systematic laboratory simulation of plume dispersion using a water channel. Three sets of experiments were conducted: (1) plume visualizations, (2) plume concentration measurements, and (3) flow velocity measurements. Results from this study shows that the deployment of sound barriers induces a recirculating flow over the roadway which transports the surface released emissions to the upwind side of the roadway, and then shifts the plume upward through an induced updraft motion. Plume visualizations clearly demonstrate that the presence of SBs induce significant vertical mixing and updraft motion on the roadway which increases the initial plume dilution and plume height and consequently results in reduced downwind ground level concentrations. Although different SB configurations result in different localized flow patterns, the dispersion pattern does not change significantly after several SB heights downwind of the roadway.

Hydrogen remains an attractive alternative fuel to petroleum and a number of investigators claim that adding hydrogen to the air intake manifold of a diesel engine will reduce criteria emissions and diesel fuel consumption. Such claims are appealing when trying to simultaneously reduce petroleum consumption, greenhouse gases and criteria pollutants. The goal of this research was to measure the change in criteria emissions (CO, NOx, and PM 2.5) and greenhouse gases such as carbon dioxide (CO2), using standard test methods for a wide range of hydrogen addition rates. A two-stroke Detroit Diesel Corporation 12V-71TI marine diesel engine was mounted on an engine dynamometer and tested at three out of the four loads specified in the ISO 8178-4 E3 emission test cycle and at idle. The engine operated on CARB ultra-low sulfur #2 diesel with hydrogen added at flow rates of 0, 22 and 220 SLPM. As compared with the base case without hydrogen, measurements showed that hydrogen injection at 22 and 220 SLPM had negligible influence on the overall carbon dioxide specific emission, EFCO2. However, in examining data at each load the data revealed that at idle EFCO2 was reduced by 21% at 22 SLPM (6.9% of the added fuel energy was from hydrogen) and 37.3% at 220 SLPM (103.1% of the added fuel energy was from hydrogen). At all other loads, the influence of added hydrogen was insignificant. Specific emissions for nitrogen oxides, EFNOx, and fine particulate matters, EFPM 2.5, showed a trade-off relationship at idle. At idle, EFNO x was reduced by 28% and 41% with increasing hydrogen flow rates, whilst EFPM2.5 increased by 41% and 86% respectively. For other engine loads, EFNOx and EFPM2.5 did not change significantly with varying hydrogen flow rates. One of the main reasons for the greater impact of hydrogen at idle is that the contribution of hydrogen to the total fuel energy is much higher at idle as compared to the other loads. The final examination in this paper was the system energy balance when hydrogen is produced by an on-board electrolysis unit. An analysis at 75% engine load showed that hydrogen production increased the overall equivalent fuel consumption by 2.6% at 22 SLPM and 17.7% at 220 SLPM. © 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

The measurements taken during the Vertical Transport and Mixing Experiment (VTMX, October, 2000) on a northeastern slope of Salt Lake Valley, Utah, were used to calculate the statistics of velocity fluctuations in a katabatic gravity current in the absence of synoptic forcing. The data from ultrasonic anemometer-thermometers placed at elevations 4.5 and 13.9 m were used. The contributions of small-scale turbulence and waves were isolated by applying a high-pass digital (Elliptical) filter, whereupon the filtered quantities were identified as small-scale turbulence and the rest as internal gravity waves. Internal waves were found to play a role not only at canonical large gradient Richardson numbers (Rig > 1), but sometimes at smaller values (0.1 < Rig < 1), in contrast to typical observations in flat-terrain stable boundary layers. This may be attributed, at least partly, to (critical) internal waves on the slope, identified by Princevac et al. [1], which degenerate into turbulence and help maintain an active internal wave field. The applicability of both Monin-Obukhov (MO) similarity theory and local scaling to filtered and unfiltered data was tested by analyzing rms velocity fluctuations as a function of the stability parameter z/L, where L is the Obukhov length and z the height above the ground. For weaker stabilities, z/L < 1, the MO similarity and local scaling were valid for both filtered and unfiltered data. Conversely, when z/L > 1, the use of both scaling types is questionable, although filtered data showed a tendency to follow local scaling. A relationship between z/L and Rig was identified. Eddy diffusivities of momentum KM and heat KH were dependent on wave activities, notably when Rig > 1. The ratio KH/KM dropped well below unity at high Rig, in consonance with previous laboratory stratified shear layer measurements as well as other field observations. © 2014 Springer Science+Business Media Dordrecht.

Theoretical and field observational studies on mean velocity and temperature fields of quasi-steady nocturnal downslope (katabatic) flows on sloping surfaces are reported for the case of very wide valleys in the presence of weak synoptic winds. Because of the lateral constraints on the flow, Coriolis effects are considered negligible. The layer-averaged equations of Manins and Sawford were used for the analysis. It is shown that (i) in the absence of significant turbulent entrainment into the current (i.e., at large Richardson numbers Ri = [DELTA]h cos[alpha]/[U.sup.2]) the downslope flow velocity U is related to the slope length ([L.sub.H]), slope angle ([alpha]), and the buoyancy jump between the current and the background atmosphere ([DELTA]) as U = )[[lambda].sub.u][([DELTA] [L.sub.H] sin[alpha]).sup.1/2], where [[lambda].sub.u] is a constant and h is the flow depth; (ii) on very long slopes h is proportional to [L.sub.h][(tan[alpha]).sup.1/2]; and (iii) under highly stable conditions (i.e., Ri > 1) the katabatic flow exhibits pulsations with period [T.sub.0] = 2[pi]/N sin[alpha], where N is the buoyancy frequency of the background atmosphere. These predictions are verified principally using observations made during the Vertical Transport and Mixing Experiment (VTMX) conducted in Salt Lake City, Utah, in October 2000. By assuming the flow follows a straight line trajectory to the nearest ridgeline a good agreement was found between the predictions and observations over appropriate Richardson number ranges. For Ri > 1.5, [[lambda].sub.u] [approximately equal to] 0.2, although [[lambda].sub.u] was a decreasing function of Ri at lesser stabilities. Oscillations with period [T.sub.0] are simply alongslope (critical) internal-wave oscillations with a slope-normal wavenumber, which are liable for degeneration into turbulence during their reflection. These critical internal waves may be responsible, at least partly, for weak sustained turbulence often observed in complex-terrain nocturnal boundary layer flows.

The theoretical and laboratory studies on mean velocity and temperature fields of an unsteady atmospheric boundary layer on sloping surfaces reported here were motivated by recent field observations on thermally driven circulation in very wide valleys in the presence of negligible synoptic winds. The upslope (anabatic) flow on a long, shallow, heated (with a buoyancy flux [F.sub.bs]) slope of inclination a located adjoining a level plane and the effects of cooling of the slope on this flow during the evening transition are studied for the case of a gentle slope for which the length of the sloping plane far exceeds the thickness h of the convective boundary layer. First, a theoretical analysis is presented for the mean upslope flow velocity [U.sub.M], noting that the turbulence but not the mean flow structure therein is similar to that on a level terrain. The analysis, which is based on mean momentum and heat equations as well as closure involving level-terrain turbulence parameterizations, shows that [U.sub.M] is proportional to [a.sup.1/3] [w.sub.*] where [w.sub.*] = [([F.sub.bs] h).sup.1/3]. Second, new physical effects associated with evening transition are elicited by considering the idealized case of (specified) cooling the upslope flow on a simple slope. Theory and available field data show that, because of their inertia and although the heating ceases, upslope winds decay only slowly over a period of about 10(h/[U.sub.M]), which is tantamount to several hours on gentle slopes, whereupon flow reversal occurs from upslope to downslope. During this stage, because the air is cooling as it rises up the slope, its potential energy increases, resulting in momentary stagnation of the airflow at a location within a few meters above the surface (in the form of a transition front) followed by local overturning due to convective instabilities; this scenario is consistent with some field observations but has not been observed in mesoscale model simulations because of insufficient resolution to capture the front. A laboratory experiment conducted by subjecting an upslope flow to a rapidly changing surface flux confirmed the theoretical result that flow reversal occurs at a finite distance along the slope with the appearance of a front, which quickly migrates down the slope as the first front of the ensuing katabatic current.

To the Editors: David Cacchione and Lincoln Pratson have proposed that internal tidal waves can be a principal factor that determines the angle of oceanic continental slope ('Internal Tides and […]

The difficulties associated with the parameterization of turbulence in the stable nocturnal planetary boundary layer (PBL) have been a great challenge for the nighttime predictions from mesoscale meteorological models such as MM5. As such, there is a general consensus on the need for better stable boundary-layer parameterizations. To this end, two new turbulence parameterizations based on the measurements of the Vertical Transport and Mixing (VTMX) field campaign were implemented and evaluated in MM5. A unique aspect of this parameterization is the use of a stability-dependent turbulent Prandtl number that allows momentum to be transported by the internal waves, while heat diffusion is impeded by the stratification. This improvement alleviates the problem of over-prediction of heat diffusion under stable conditions, which is a characteristic of conventional atmospheric boundary-layer schemes, such as the Medium Range Forecast (MRF) and Blackadar schemes employed in MM5. The predictions made with the new PBL scheme for the complex terrain airshed of Salt Lake City were compared with those made with a default scheme of MM5, and with observations made during the VTMX campaign. The new schemes showed an improvement in predictions, particularly for the nocturnal near-surface temperature. Surface wind predictions also improved slightly, but not to the extent of temperature predictions. The default MRF scheme showed a significantly higher surface temperature than observed, which could be attributed to the enhanced vertical heat exchange brought about by its turbulence parameterization. The modified parameterizations reduced the surface sensible heat flux, thus enhancing the strength of the near-surface inversion and lowering the temperature towards the observed values. [ABSTRACT FROM AUTHOR]

Recently, many urban areas of the world have experienced rapid growth of population and industrial activity raising concerns of environmental deterioration. To meet challenges associated with such rapid urbanization, it has become necessary to implement wise strategies for environmental management and planning, addressing the exclusive demands of urban zones for maintaining environmental sustainability and functioning with minimum disruption. These strategies and related publicpolicy must be based on state-of-the-science tools for environmentalforecasting, in particular, on mathematical models that accurately incorporate physical, biological, chemical and geological processes atwork on urban scales. Central to such models are the mechanics of environmental fluids (air and water) and their transport and transformation characteristics. Although much progress has been made on understanding environmental flow phenomena, a myriad of issues akin to urbanflow, the transport phenomena, air and water quality and health issues (epidemiology) remain to be understood and quantified. We propose to initiate a new focus area - Urban Fluid Mechanics (UFM) - tailoredto research on such issues. For optimal societal impact, UFM must delve into fundamental and applied fluid flow problems of immediate utility for the development of urban public policy and environmental regulations. Such efforts often entail the use of 'whole' systems approach to environmental studies, requiring careful synthesis between crosscutting areas. In this paper, a few topics in the realm of UFM are presented, the theme being the flow and air quality in urban areas. Topics such as the scales of flow, the atmospheric boundary layer, pollutants and their transport and modeling of flow and air quality are briefly reviewed, discussed and exemplified using case studies. Identification of important flow-related issues, rigorous multidisciplinaryapproaches to address them and articulation of results in the context of s [ABSTRACT FROM AUTHOR]

The impact of cooking with solid fuels on neighborhood-scale PM 2.5 concentrations in rural towns and communities is poorly quantified due to the lack of credible ground-level monitoring sites and spatial heterogeneity at a scale that is below the resolution of remote sensing GEOS-Chem hybrid models. Emissions of PM 2.5 from use of open fires for cooking in rural Mexico are known to cause poor indoor air quality. The effectiveness of different intervention strategies to reduce such pollution exposures also varies because of different local building densities and source intensities. In this study, the effectiveness of stove intervention strategies on the neighborhood-scale PM 2.5 concentrations were evaluated in a village Cucuchucho, located in the Purepecha highlands of Mexico. The Quick Urban & Industrial Complex (QUIC) is deployed in the assessment. The model's performance in simulating interactions between pollutants and flow around building structures is validated through comparison with a water channel experiment, which shows good quantitative agreement. The case study simulation results demonstrate that upstream households contributed ∼30% of concentrations, and current trends will not meet WHO air quality guidelines or interim targets. The magnitude of neighborhood-scale PM 2.5 concentrations depends on the intervention and community structure. Based on these simulations, a statistical model is presented to estimate ambient neighborhood PM 2.5 pollution concentrations for more communities at a regional level. The statistical model allows neighborhood PM 2.5 pollution to be included in estimates of health burdens from household pollution in Mexico using readily accessible community parameters., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

The global pandemic of COVID-19 has highlighted the importance of understanding the role that exhaled droplets play in virus transmission in community settings. Computational Fluid Dynamics (CFD) enables systematic examination of roles the exhaled droplets play in the spread of SARS-CoV-2 in indoor environments. This analysis uses published exhaled droplet size distributions combined with terminal aerosol droplet size based on measured peak concentrations for SARS-CoV-2 RNA in aerosols to simulate exhaled droplet dispersion, evaporation, and deposition in a supermarket checkout area and rideshare car where close proximity with other individuals is common. Using air inlet velocity of 2 m/s in the passenger car and ASHRAE recommendations for ventilation and comfort in the supermarket, simulations demonstrate that exhaled droplets <20 μm that contain the majority of viral RNA evaporated leaving residual droplet nuclei that remain aerosolized in the air. Subsequently ~ 70% of these droplet nuclei deposited in the supermarket and the car with the reminder vented from the space. The maximum surface deposition of droplet nuclei/m 2 for speaking and coughing were 2 and 819, 18 and 1387 for supermarket and car respectively. Approximately 15% of the total exhaled droplets (aerodynamic diameters 20-700 µm) were deposited on surfaces in close proximity to the individual. Due to the non-linear distribution of viral RNA across droplet sizes, however, these larger exhaled droplets that deposit on surfaces have low viral content. Maximum surface deposition of viral RNA was 70 and 1.7 × 10 3 virions/m 2 for speaking and 2.3 × 10 4 and 9.3 × 10 4 virions/m 2 for coughing in the supermarket and car respectively while the initial airborne concentration of viral RNA was 7 × 10 6 copies per ml. Integrating the droplet size distributions with viral load distributions, this study helps explain the apparent importance of inhalation exposures compared to surface contact observed in the pandemic., Competing Interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article., (© The Author(s) 2023.)

Since of its introduction in 1980s, laser speckle imaging has become a powerful tool in flow imaging. Its high performance and low cost made it one of the preferable imaging methods. Initially, speckle contrast measurements were the main algorithm for analyzing laser speckle images in biological flows. Speckle contrast measurements, also referred as Laser Speckle Contrast Imaging (LSCI), use statistical properties of speckle patterns to create mapped image of the blood vessels. In this communication, a new method named Laser Speckle Optical Flow Imaging (LSOFI) is introduced. This method uses the optical flow algorithms to calculate the apparent motion of laser speckle patterns. The differences in the apparent motion of speckle patterns are used to identify the blood vessels from surrounding tissue. LSOFI has better spatial and temporal resolution compared to LSCI. This higher spatial resolution enables LSOFI to be used for autonomous blood vessels detection. Furthermore, Graphics Processing Unit (GPU) based LSOFI can be used for quasi real time imaging., (Copyright © 2018 Elsevier Inc. All rights reserved.)