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The Mississippi River Delta Front (MRDF) is a subaqueous apron of rapidly deposited and weakly consolidated sediment extending from the subaerial portions of the Birdsfoot Delta of the Mississippi River, long characterized by mass-wasting sediment transport. Four (4) depositional environments dominate regionally (an undisturbed topset apron, mudflow gully, mudflow lobe, and prodelta), centering around mudflow distribution initiated by a variety of factors (hurricanes, storms, and fluid pressure). To better understand the spatiotemporal scales of the events as well as the controlling processes, eight cores (5.8–8.0 m long) taken offshore from the South Pass (SP) and the Southwest Pass (SWP) were analyzed for gamma density, grain size, sediment fabric (X-radiography), and geochronology (210Pb/137Cs radionuclides). Previous work has focused on the deposition of individual passes and has been restricted to 210Pb activities and the corresponding decreased gamma density indicate the presence of gravity-driven mass failures. 210Pb/137Cs indicates that gully sedimentary sediment accumulation since 1953 is greater than 580 cm (sediment accumulation rate [SAR] of 12.8 cm/y) in the southwest pass site, and a lower SAR of the South Pass gully sites (2.6 cm/y). This study shows that (1) recent dated mudflow deposits are identifiable in both the SWP and SP; (2) SWP mudflows have return periods of 10.7 y, six times more frequent than at the SP (66.7 y); (3) 210Pb inventories display higher levels in the SWP area, with the highest focusing factors in proximal/gully sedimentation, and (4) submarine landslides in both study areas remain important for sediment transport despite the differences in sediment delivery and discharge source proximity.

Air intrusion into municipal solid waste landfills can cause a localized switch from anaerobic to aerobic biodegradation adjacent to the intrusion. The purpose of this study was to explore the effects on temperature and gas composition of air intrusion into an idealized anaerobic landfill. Two scenarios of air intrusion and injection were simulated using a mechanistic landfill model built into TOUGH2. The modeled landfill geometry and properties are based on an actual U.S. landfill. The simulation results show that air intrusion can cause a quick switch from anaerobic to aerobic conditions and as a result, cause a fast increase in temperature of up to 30 °C associated with stimulation of aerobic biodegradation reactions. Associated with the change to aerobic conditions is a decrease in CH4/CO2 (v/v) ratio in the landfill gas. Depending on the air flow rate intruding or injecting into the landfill, localized aerobic biodegradation is stimulated and as a result heat generation rate of 10 to 150 W/m3 leads to temperature increase. Temperature increase near a temporary air intrusion lasts no longer than a few weeks while the high temperatures in deep layers could last up to one year.

This technical paper investigates the influence of sample size and geologic characteristics on the geotechnical design of levee embankments. Sample quality plays a vital role in quantifying engineering properties for levee embankment projects, and numerous studies have highlighted the impact of sample disturbance on such engineering properties. Despite this evidence, conventional tube and piston samplers of different diameters continue to be widely used, potentially leading to underestimation of shear strength. The paper focuses on comparing 7.6 cm and 12.7 cm diameter undisturbed Shelby tube samples and CPT data collected from three levee sites in the Greater New Orleans Area, Louisiana, USA, which encompass diverse geologic histories. The study aims to assess the effect of industry used samples size and geology on levee construction costs. The findings provide valuable insights into optimizing sample collection methods and improving geotechnical design for earthen embankments.

Many Mississippi River Delta studies have shown recent declines in fluvial sediment load from the river and associated land loss. In contrast, recent sedimentary processes on the subaqueous delta are less documented. To help address this knowledge gap, multicores were collected offshore from the three main river outlets at water depths of 25–280 m in June 2017 just after the peak river discharge period, with locations selected based on 2017 U.S. Geological Survey seabed mapping. The coring locations included the undisturbed upper foreset, mudflow lobes, gullies, and the undisturbed prodelta. Nine multicores were analyzed for Beryllium-7 activity, and four cores were analyzed for excess Thorium-234 activity via gamma spectrometry, granulometry and X-radiography. Our results indicate a general trend of declining 7Be and 234Th activities and inventories with increasing distance from sources and in deeper water. The core X-radiographs are graded from the predominantly physically stratified nearshore to the more bioturbated offshore, consistent with the sedimentation patterns. Sediment focusing assessed via the 7Be and 234Th sediment inventories shows preferential sedimentation in gully and lobe environments, whereas the upper foreset and prodelta focusing factors are relatively depleted. Overall, short-term sediment deposition from the main fluvial source remains active offshore from all three major river outlets, despite the overall declining river load.

Article highlights The thermo-mechanical procedure was used to manufacture auxetic foams. Effect of processing parameters on the foam mechanical properties was investigated. Foams Poisson’s ratio and Young’s modulus were measured in two strain values.

The Mississippi River Delta Front (MRDF) is a subaqueous apron of rapidly deposited and weakly consolidated sediment extending from the subaerial portions of the Birdsfoot Delta of the Mississippi River, long characterized by mass-wasting sediment transport. Four (4) depositional environments dominate regionally (an undisturbed topset apron, mudflow gully, mudflow lobe, and prodelta), centering around mudflow distribution initiated by a variety of factors (hurricanes, storms, and fluid pressure). To better understand the spatiotemporal scales of the events as well as the controlling processes, eight cores (5.8–8.0 m long) taken offshore from the South Pass (SP) and the Southwest Pass (SWP) were analyzed for gamma density, grain size, sediment fabric (X-radiography), and geochronology (210Pb/137Cs radionuclides). Previous work has focused on the deposition of individual passes and has been restricted to <3 m core penetration, limiting its geochronologic completeness. Building on other recent studies, within the mudflow gully and lobe cores, the homogeneous stepped profiles of 210Pb activities and the corresponding decreased gamma density indicate the presence of gravity-driven mass failures. 210Pb/137Cs indicates that gully sedimentary sediment accumulation since 1953 is greater than 580 cm (sediment accumulation rate [SAR] of 12.8 cm/y) in the southwest pass site, and a lower SAR of the South Pass gully sites (2.6 cm/y). This study shows that (1) recent dated mudflow deposits are identifiable in both the SWP and SP; (2) SWP mudflows have return periods of 10.7 y, six times more frequent than at the SP (66.7 y); (3) 210Pb inventories display higher levels in the SWP area, with the highest focusing factors in proximal/gully sedimentation, and (4) submarine landslides in both study areas remain important for sediment transport despite the differences in sediment delivery and discharge source proximity. [ABSTRACT FROM AUTHOR]

Soil classification methods currently rely on soil borings or cone/piezocone penetrometer tests (CPT/CPTu). Literature provides several methods that classify soils based on two parameters (typically tip resistance and friction sleeve/porewater pressure) obtained from CPTu data, defining a soil behavior type. However, these methods face challenges in reliably classifying certain soils, such as organic soils. Robust and complex analyses are required to classify organic soils accurately. In this study, a random forest (RF) based method is developed to predict the presence and depth of organic soils. The RF model utilized features from CPTu soundings including tip resistance, sleeve friction, and pore pressure. The true location of organic soils, derived from index properties obtained from soil borings, served as the model's outputs. Unseen CPTu data was used to predict organic soils throughout the entire project alignment, serving as validation for the model. The model achieved an F1 score of 0.89. Settlement analyses were conducted to evaluate the practical implications of the model's predictions on levee fill costs. The RF-based model yielded settlement predictions that closely matched those obtained through boring predictions. In contrast, traditional classification methods underestimated settlements, resulting in lower estimates for levee fill costs. [ABSTRACT FROM AUTHOR]

The Rockefeller Wildlife Refuge, located along the Chenier Plain in Southwest Louisiana, was the location of the sequential landfall of two major hurricanes in the 2020 hurricane season. To protect the rapidly retreating coastline along the Refuge, a system of breakwaters was constructed, which was partially completed by the 2020 hurricane season. Multi-institutional, multi-disciplinary rapid response deployments of wave gauges, piezometers, geotechnical measurements, vegetation sampling, and drone surveys were conducted before and after Hurricanes Laura and Delta along two transects in the Refuge; one protected by a breakwater system and one which was the natural, unprotected shoreline. Geomorphological changes were similar on both transects after Hurricane Laura, while after Delta there was higher inland sediment deposition on the natural shoreline. Floodwaters drained from the transect with breakwater protection more slowly than the natural shoreline, though topography profiles are similar, indicating a potential dampening or complex hydrodynamic interactions between the sediment—wetland—breakwater system. In addition, observations of a fluidized mud deposit in Rollover Bayou in the Refuge are presented and discussed in context of the maintenance of wetland elevation and stability in the sediment starved Chenier Plain.

Abstract Introduction To reduce mortality in hospitalized patients with COVID‐19 and cardiovascular disease (CVD), it is necessary to understand the relationship between patient's symptoms, risk factors, and comorbidities with their mortality rate. To the best of our knowledge, this paper is the first which take into account the determinants like risk factors, symptoms, and comorbidities leading to mortality in CVD patients who are hospitalized with COVID‐19. Methods This study was conducted on 660 hospitalized patients with CVD and COVID‐19 recruited between January 2020 and January 2021 in Iran. All patients were diagnosed with the previous history of CVD like angina, myocardial infarction, heart failure, cardiomyopathy, abnormal heart rhythms, and congenital heart disease before they were hospitalized for COVID‐19. We collected data on patient's signs and symptoms, clinical and paraclinical examinations, and any underlying comorbidities. t test was used to determine the significant difference between the two deceased and alive groups. In addition, the relation between pairs of symptoms and pairs of comorbidities has been determined via correlation computation. Results Our findings suggest that signs and symptoms such as fever, cough, myalgia, chest pain, chills, abdominal pain, nausea, vomiting, diarrhea, and anorexia had no impact on patients' mortality. There was a significant correlation between COVID‐19 cardiovascular patients' mortality rate and symptoms such as headache, loss of consciousness (LOC), oxygen saturation less than 93%, and need for mechanical ventilation. Conclusions Our results might help physicians identify early symptoms, comorbidities, and risk factors related to mortality in CVD patients hospitalized for COVID‐19.

Effective disaster debris management requires reasonable predictions pre-hazard and estimates post-hazard of debris for a community to get back to normal sooner. However, there is a lack of data related to post-disaster waste quantities that could validate and improve debris predictions. This knowledge gap can be addressed by using remote sensing technology to quantify disaster debris promptly following a hazard. This study aimed to demonstrate and compare multiple remote sensing tools available for quantifying disaster debris using post-disaster data collected following Hurricane Ida. The tools used in this study are satellite imagery, emergency response airborne imagery, unmanned aerial vehicles (UAVs), and terrestrial laser scanning (TLS). We found that satellite imagery is useful for quantifying vegetative debris generation and transportation across vast areas, however it is often limited by spatial and temporal resolutions. Emergency response airborne imagery, collected within days following the hazard, is well-suited for quantifying transported vegetative debris and can assist debris clearance of emergency service routes across large areas, although it can be limited spatially and temporally to the interests of the acquiring agency. UAVs and TLS can provide precise volumes of debris but UAVs may be a better option due to their lower cost and computational demand. Guidance is provided for selecting a remote sensing tool based on the desired application and available resources, which can assist decision making for disaster waste managers. [ABSTRACT FROM AUTHOR]

Coastal wetlands are experiencing accelerated rates of fragmentation and degradation due to sea-level rise, sediment deficits, subsidence, and salt-water intrusion. This reduces their ability to provide ecosystem benefits, such as wave attenuation, habitat for migratory birds, and a sink for carbon and nitrogen cycles. A deteriorated back barrier wetland in New Jersey, USA was nourished through thin layer placement (TLP) of dredged sediment in 2016. A field investigation was conducted in 2019 using a cone penetrometer (CPT) to quantify the establishment of soil strength post sediment nourishment compared to adjacent reference sites in conjunction with traditional wetland performance measures. Results show that the nourished area exhibited weaker strengths than the reference sites, suggesting the root system of the vegetation is still establishing. The belowground biomass measurements correlated to the CPT strength measurements, demonstrating that shear strength measured from the cone penetrometer could serve as a surrogate to monitor wetland vegetation trajectories. In addition, heavily trafficked areas underwent compaction from heavy equipment loads, inhibiting the development of vegetation and highlighting how sensitive wetlands are to anthropogenic disturbances. As the need for more expansive wetland restoration projects grow, the CPT can provide rapid high-resolution measurements across large areas supplying government and management agencies with vital establishment trajectories.

Many Mississippi River Delta studies have shown recent declines in fluvial sediment load from the river and associated land loss. In contrast, recent sedimentary processes on the subaqueous delta are less documented. To help address this knowledge gap, multicores were collected offshore from the three main river outlets at water depths of 25–280 m in June 2017 just after the peak river discharge period, with locations selected based on 2017 U.S. Geological Survey seabed mapping. The coring locations included the undisturbed upper foreset, mudflow lobes, gullies, and the undisturbed prodelta. Nine multicores were analyzed for Beryllium-7 activity, and four cores were analyzed for excess Thorium-234 activity via gamma spectrometry, granulometry and X-radiography. Our results indicate a general trend of declining 7Be and 234Th activities and inventories with increasing distance from sources and in deeper water. The core X-radiographs are graded from the predominantly physically stratified nearshore to the more bioturbated offshore, consistent with the sedimentation patterns. Sediment focusing assessed via the 7Be and 234Th sediment inventories shows preferential sedimentation in gully and lobe environments, whereas the upper foreset and prodelta focusing factors are relatively depleted. Overall, short-term sediment deposition from the main fluvial source remains active offshore from all three major river outlets, despite the overall declining river load. [ABSTRACT FROM AUTHOR]

Accurate forecasts and estimates of disaster debris are critical for effective debris management planning. However, detailed postdisaster waste data to validate and improve debris predictions is often unavailable. In this study, a postdisaster waste dataset collected in Beaumont, Texas, following widespread flooding from Hurricane Harvey that included debris tonnages and coordinate locations of each debris removal in residential areas was investigated. The dataset was utilized to quantify the amount of debris produced, identify the factors that influenced debris generation in different areas of the city, and compare Beaumont debris tonnages to predictive models. The study found that the type of flooding (riverine versus urban) had the highest influence on debris generation. Riverine flooded areas generated twice the debris tonnage as urban flooded areas. Elevation appeared to influence debris generation when considered with the type of flooding. FEMA's correlation for flooded personal property was within the same magnitude of debris quantities, while other methods significantly overpredicted debris quantities (up to one order of magnitude) due to their generality. However, they can be adapted for flood-generated debris. Urban flooding is an increasingly prevalent issue following a natural hazard and generates considerable amounts of debris, but is not addressed in current disaster management plans. Estimation methods that consider urban flooding should be developed. [ABSTRACT FROM AUTHOR]