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Microfluidic chips can generate emulsions, which can be used to synthesize polymer microparticles that have superior pharmacological performance compared to particles prepared by conventional techniques. However, low production rates of microfluidics remains a challenge to successfully translate laboratory discoveries to commercial manufacturing. We present a silicon and glass device that incorporates an array of 10,260 (285 × 36) microfluidic droplet generators that uses only a single set of inlets and outlets, increasing throughput by >10,000× compared to microfluidics with a single generator. Our design breaks the tradeoff between the number of generators and the maximum throughput of individual generators by incorporating high aspect ratio flow resistors. We test these design strategies by generating hexadecane microdroplets at >1 trillion droplets per h with a coefficient of variation CV <3%. To demonstrate the synthesis of biocompatible microparticles, we generated 8–16 µm polycaprolactone particles with a CV <5% at a rate of 277 g h −1 . Microfluidic-generated polymer microparticles have been shown to have superior pharmacological performance; yet, mass production remains a challenge to industrial application. Here, the authors present and test a device that incorporates arrays of microparticle generators for mass production.

This paper details and tests numerical improvements to the ADvanced CIRCulation (ADCIRC) model, a widely used finite-element method shallow-water equation solver, to more accurately and efficiently model global storm tides with seamless local mesh refinement in storm landfall locations. The sensitivity to global unstructured mesh design was investigated using automatically generated triangular meshes with a global minimum element size (MinEle) that ranged from 1.5 to 6 km. We demonstrate that refining resolution based on topographic seabed gradients and employing a MinEle less than 3 km are important for the global accuracy of the simulated astronomical tide. Our recommended global mesh design (MinEle = 1.5 km) based on these results was locally refined down to two separate MinEle values (500 and 150 m) at the coastal landfall locations of two intense storms (Hurricane Katrina and Super Typhoon Haiyan) to demonstrate the model's capability for coastal storm tide simulations and to test the sensitivity to local mesh refinement. Simulated maximum storm tide elevations closely follow the lower envelope of observed high-water marks (HWMs) measured near the coast. In general, peak storm tide elevations along the open coast are decreased, and the timing of the peak occurs later with local coastal mesh refinement. However, this mesh refinement only has a significant positive impact on HWM errors in straits and inlets narrower than the MinEle and in bays and lakes separated from the ocean by these passages. Lastly, we demonstrate that the computational performance of the new numerical treatment is 1 to 2 orders of magnitude faster than studies using previous ADCIRC versions because gravity-wave-based stability constraints are removed, allowing for larger computational time steps.

Freshwater diversions manage water shortages, salinity, and control floodwater by redirecting river flows; however, their full ecological and hydrological impact remains unknown. This study examines the Lake Pontchartrain Estuary in Louisiana using a hydrodynamic model and Lagrangian particle tracking to assess how diversion operations (open, closed) and tributary discharge levels (low, median, high) influence water exposure time—the cumulative duration water remains in a domain, including re‐entry. Exposure time was analyzed based on the time required for 50%, 75%, and 90% of released particles (E50 ${E}_{50}$, E75 ${E}_{75}$, and E90 ${E}_{90}$) to leave a defined region of interest (ROI). Results show that when the diversion is open, high tributary discharge reduces exposure times by 51% compared to low discharge. In contrast, when closed, tributary discharge has minimal effect. To identify zones vulnerable to poor water quality due to stagnant water, the spatial heterogeneity of exposure time was evaluated using two metrics: system‐wide (time water remains in a system) and localized (time water remains within a ROI) exposure times. The spatial distribution and magnitude of increased exposure times varied between metrics and tributary discharge, highlighting the complexity of transport dynamics. For example, low tributary discharge led to larger isolated zones with longer system‐wide and localized exposure times. High tributary discharge created direct flow paths of diversion‐sourced water through tidal inlets, short‐circuiting the system and creating flow separation. These findings establish a framework for identifying transport mechanisms that influence exposure time and highlighting areas that may be vulnerable to poor water quality.

Chan, M.C., 2023. Sizing a small tidal inlet for restoration. Journal of Coastal Research, 39(4), 610–624. Charlotte (North Carolina), ISSN 0749-0208. Coastal inlets located on active shorelines can be vulnerable to shoaling and closure. It is not uncommon for some of these inlets to fall under the category of small tidal inlets with cross-sectional areas <100 m2 and to be transitional in stability characteristics such that neither the classic large-inlet O'Brien-Jarrett equilibrium formulas nor the small-inlet Byrne stability criteria apply fully. The Flax Pond inlet, a dual-jettied small inlet located on the south shore of Long Island Sound, New York, is an example of this class of inlets. The inlet, which connects Flax Pond, a degraded tidal marsh embayment, to Long Island Sound, was analyzed to support a proposed plan to reconstruct the twin jetties and restore the pond's tidal prism to its conditions in the early 1970s to prevent further loss of wetland and ecosystem diversity. The lack of directly suitable stability criteria presented a challenge because an extrapolative use of unsuitable criteria could entail unacceptable risks. The issue necessitated a comprehensive, process-driven analysis of the littoral and inlet conditions to frame a solution. An approach involving multiple stability criteria was followed to determine the inlet dimensions needed to achieve the restoration objectives. It was demonstrated that, with a process-based understanding and informed assumptions, a transitional small inlet can be sized with reasonable confidence.

Surface water and surface water related flood modelling at the city-scale is challenging due to a range of factors including the availability of subsurface data and difficulty in deriving runoff inputs and surcharge for individual storm sewer inlets. Most of the research undertaken so far has been focusing on local-scale predictions of sewer surcharge induced surface flooding, using a 1D/1D or 1D/2D coupled storm sewer and surface flow model. In this study, we describe the application of an urban hydro-inundation model (FloodMap-HydroInundation2D) to simulate surface water related flooding arising from extreme precipitation at the city-scale. This approach was applied to model an extreme storm event that occurred on 12 August 2011 in the city of Shanghai, China, and the model predictions were compared with a 'crowd-sourced' dataset of flood incidents. The results suggest that the model is able to capture the broad patterns of inundated areas at the city-scale. Temporal evaluation also demonstrates a good level of agreement between the reported and predicted flood timing. Due to the mild terrain of the city, the worst-hit areas are predicted to be topographic lows. The spatio-temporal accuracy of the precipitation and micro-topography are the two critical factors that affect the prediction accuracies. Future studies could be directed towards making more accurate and robust predictions of water depth and velocity using higher quality topographic, precipitation and drainage capacity information.

Mortality from being struck by a motorized watercraft is considerable for many aquatic vertebrates around the world, including sea turtles. We studied stranded (i.e., dead, sick, or injured) sea turtles found in Florida, USA, during 1986–2014 and identified those with sharp force or blunt force injuries indicative of a vessel strike. About a third of stranded loggerheads (Caretta caretta), green turtles (Chelonia mydas), and leatherbacks (Dermochelys coriacea) had a vessel-strike injury (VSI). The frequency of this injury was lower but still substantial for stranded Kemp’s ridleys (Lepidochelys kempii; 26.1%) and hawksbills (Eretmochelys imbricata; 14.8%). Over the study period, the annual number of stranded loggerheads, green turtles, and Kemp’s ridleys with a VSI increased as did the annual number of vessels registered in Florida. Eighty-one percent of the stranded turtles with a VSI were found in the southern half of Florida and 66% of those were found along the southeast coast. By coastal county, the proportion of stranded sea turtles with a VSI was positively related to the mean annual number of registered vessels. The percentage occurrence of a VSI was highest for adult loggerheads, green turtles, and leatherbacks, and reproductively active individuals appeared to be particularly vulnerable to these injuries. We conducted necropsies on 194 stranded sea turtles with a VSI and concluded that this injury was the cause of death or the probable cause of death in ≥92.8% of these cases. During 2000–2014, we estimate that the mean annual numbers of stranded sea turtles that died from a VSI were 142–229 loggerheads, 101–162 green turtles, 16–32 Kemp’s ridleys, 4–6 leatherbacks, and 2–4 hawksbills. Considering that only about 10–20% of sea turtles that died likely washed ashore, the overall annual mortality may have been 5–10 times greater than that represented by strandings. Most of the significant clusters of stranded sea turtles with a VSI occurred at inlets or passes and the probability that a stranded sea turtle had a VSI decreased with increasing distance from inlets or passes, navigable waterways, and marinas. We suggest focusing initial management efforts on reducing watercraft-related mortality for all sea turtle species around 8 inlets in southeast Florida, reproductively active loggerheads and green turtles along the coast of southeast Florida, and Kemp’s ridleys and adult male loggerheads at passes along the coast of southwest Florida. Published 2019. This article is a U.S. Government work and is in the public domain in the USA.

Extreme water levels generating flooding in estuarine and coastal environments are often driven by compound events, where many individual processes such as waves, storm surge, streamflow, and tides coincide. Despite this, extreme water levels are typically modeled in isolated open-coast or estuarine environments, potentially mischaracterizing the true risk of flooding facing coastal communities. This paper explores the variability of extreme water levels near the tribal community of La Push, within the Quileute Indian Reservation on the Washington state coast, where a river signal is apparent in tide gauge measurements during high-discharge events. To estimate the influence of multiple forcings on high water levels a hybrid modeling framework is developed, where probabilistic simulations of joint still water level and river discharge occurrences are merged with a hydraulic model that simulates along-river water levels. This methodology produces along-river water levels from thousands of combinations of events not necessarily captured in the observational records. We show that the 100-year still water level event and the 100-year discharge event do not always produce the 100-year along-river water level. Furthermore, along specific sections of river, both still water level and discharge are necessary for producing the 100-year along-river water level. Understanding the relative forcing driving extreme water levels along an ocean-to-river gradient will help communities within inlets better understand their risk to the compounding impacts of various environmental forcing, which is important for increasing their resilience to future flooding events.

Campi Flegrei, one of the most monitored and studied volcanic areas in the world, has recently attracted significant attention due to the reactivation of its peculiar activity, consisting of small earthquakes, geothermal phenomena and slow subsidence/rapid uplift cycles, known as bradyseism. While much of the research and of the attention focuses on potential eruptions or other volcanic-related activities, the potential hazard posed by gravitational instabilities has received little consideration. The interaction of the destabilized masses with water can trigger tsunamis, potentially affecting the whole coastline of the Gulf of Pozzuoli, which lies above the Campi Flegrei caldera. Moving from the limited available geomorphological studies of the area, a set of four landslide-tsunami scenarios (one subaerial and three submarine sources) are reconstructed. These are simulated through a sequence of numerical codes, accounting for all the phases of the tsunami process, providing insights into the distribution of tsunami energy and identifying the most affected coastal stretches. Additionally, the study explores the influence of dispersion effects in the tsunami propagation and the occurrence of resonance effects in some minor inlets of the Gulf, emphasizing the importance of accounting for complex and non-linear coastal processes when treating landslide-generated tsunamis.

During the summer 2013 Southern Aerosol and Oxidant Study (SOAS) field campaign in a rural site in the southeastern United States, the effect of hygroscopicity and composition on the phase state of atmospheric aerosol particles dominated by the organic fraction was studied. The analysis is based on hygroscopicity measurements by a Hygroscopic Tandem Differential Mobility Analyzer (HTDMA), physical phase state investigations by an Aerosol Bounce Instrument (ABI) and composition measurements using a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS). To study the effect of atmospheric aging on these properties, an OH-radical oxidation flow reactor (OFR) was used to simulate longer atmospheric aging times of up to 3 weeks. Hygroscopicity and bounce behavior of the particles had a clear relationship showing higher bounce at elevated relative humidity (RH) values for less hygroscopic particles, which agrees well with earlier laboratory studies. Additional OH oxidation of the aerosol particles in the OFR increased the O : C and the hygroscopicity resulting in liquefying of the particles at lower RH values. At the highest OH exposures, the inorganic fraction starts to dominate the bounce process due to production of inorganics and concurrent loss of organics in the OFR. Our results indicate that at typical ambient RH and temperature, organic-dominated particles stay mostly liquid in the atmospheric conditions in the southeastern US, but they often turn semisolid when dried below ∼ 50 % RH in the sampling inlets. While the liquid phase state suggests solution behavior and equilibrium partitioning for the SOA particles in ambient air, the possible phase change in the drying process highlights the importance of thoroughly considered sampling techniques of SOA particles.

Recreational boating increases globally and associated moorings are often placed in vegetated habitats important for fish recruitment. Meanwhile, assessments of the effects of boating on vegetation, and potential effects on associated fish assemblages are rare. Here, we analysed (i) the effect of small-boat marinas on vegetation structure, and (ii) juvenile fish abundance in relation to vegetation cover in shallow wave-sheltered coastal inlets. We found marinas to have lower vegetation cover and height, and a different species composition, compared to control inlets. This effect became stronger with increasing berth density. Moreover, there was a clear positive relationship between vegetation cover and fish abundance. We conclude that recreational boating and related moorings are associated with reduced cover of aquatic vegetation constituting important habitats for juvenile fish. We therefore recommend that coastal constructions and associated boating should be allocated to more disturbance tolerant environments (e.g. naturally wave-exposed shores), thereby minimizing negative environmental impacts.