Overflow Rate Research Articles

Runoff Control Performance of Three Typical Low-Impact Development Facilities: A Case Study of a Community in Beijing

The development of sponge cities advocates for sustainable urban rainwater management, effectively alleviating urban flood disasters, reducing non-point-source pollution, and promoting the recycling of rainwater resources. Low-Impact Development (LID) serves as a key strategy in this context, providing essential support for urban rainwater control and pollution reduction. To investigate the runoff control effects of LID measures and to reveal the relationship between facility runoff control performance and installation scale, this study focuses on a sponge community in Beijing. A SWMM model was constructed to analyze the rainwater flood control and pollutant load reduction effects of different LID facilities, including bio-retention cells, green roofs, and permeable pavements. Using evaluation indicators such as surface runoff, node overflow, and pollutant control rates, this study examined how facility performance varies with installation scale under different rainfall conditions. The combination scheme of LID equipment optimal configuration is designed by using multiple criteria decision analysis (MCDA) and cost–benefit theory. The results indicate significant differences in performance among the various LID facilities across different rainfall scenarios. Specifically, the optimal installation proportion for runoff and overflow control of permeable pavements were found to be between 30% and 70%. Green roofs demonstrate superior performance in handling extreme rainfall events, while bio-retention cells exhibit significant effectiveness in controlling Total Suspended Solids (TSSs). Through comprehensive performance evaluation, this study identified the optimal combination scale under a 3-year rainfall recurrence interval as 30% permeable pavements, 20% green roof, and 60% bio-retention cells. This combination effectively leverages the strengths of each facility, ensuring system stability and efficiency while also demonstrating optimal management efficiency in cost–benefit analyses. The findings of this research provide valuable insights for future urban water management and infrastructure development.

Modelling the predictive analysis of turbidity removal efficiency in the in-line coagulation and flocculation process

Coagulation and flocculation processes are commonly used in conventional water treatment plants to remove suspended solids from water. However, these methods often suffer from drawbacks such as high chemical consumption, sludge generation, and the need for huge areas, leading to high construction costs. To address these limitations, this study investigated the performance of in-line coagulation and flocculation processes as an alternative to conventional methods. The objectives were to determine the efficiency of in-line coagulation and flocculation, understand the underlying mechanisms, establish optimal operating conditions and design criteria, and to develop theoretical models for predicting turbidity removal efficiency in the in-line coagulation-flocculation process. Experiments were conducted using a continuous setup consisting of a static mixer and a 35-m helically coiled hydraulic tube flocculator.Various operating parameters, including water flow rate (100 – 800 L/hr), initial turbidity (20 – 200 NTU), and coagulant types (aluminum sulfate, poly aluminum chloride, aluminum chlorohydrate, and ferric chloride), were examined. The results demonstrated that aluminum sulfate was the appropriate coagulant for the water characteristics studied, and the in-line coagulation and flocculation processes achieved turbidity removal efficiencies of approximately 91 % under all operating conditions, with a notable 97 % removal efficiency achieved at a liquid flow rate of 600 L/hr, with a Gt value of 21,715 and an overflow rate of 2 m/hr. A prediction model of turbidity removal efficiency was developed, showing good agreement between experimental and predicted removal efficiency model, with an average deviation of about 20 %. This model can aid in determining optimal operating conditions and serve as a hybrid process in future water treatment systems, potentially applicable to other separation processes as well.

Correlation between spatial characteristics and overflow rate of back alleys in high‐density city of Hong Kong

AbstractIn recent years, scholarly attention has shifted within urban informality research from informal settlements to the appropriation of public spaces in formal urban settings. Overflow, a common research subject within this context, has drawn particular interest. This study investigates overflow dynamics in a representative district of Hong Kong, utilizing the overflow rate as a measure of the extent to which overflow occurs. Three‐dimensional (3D) scanning technology was applied to collect spatial data from back alleys. Multiple linear regression analyses were conducted to identify the spatial characteristics of back alleys that influence overflow rates. The results revealed that back alleys with a flatter spatial interface, more overhead shelter, greater numbers of alley‐shops, and shorter overall length corresponded to a higher number of overflow occurrences. Two novel findings emerged: First, a negative correlation between spatial interface unevenness and overflow rates, and second, differential impacts of the shop density and number of alley‐shops on overflow rates. These findings may serve as a valuable reference for governmental policy formulation regarding overflow management and may offer architects workable insights for designing back alleys and street spaces conducive to public use.

Side-by-Side Testing of Grit Separation Units

Two grit removal systems were tested side-by-side for the treatment of wastewater from a combined-sewer system. The two units were operated at constant flows and variable grit loads ranging from 1.2 to 745 Kg/m3 /h that covered the typical range of dry and wet weather conditions experienced at the treatment facility. The average mass grit removal for the multi-tray free vortex unit was 92.6% and it was 85.4% for the forced vortex system. Both units consistently failed to remove particles with sand equivalent sizes, which their respective overflow rates would otherwise predict. This observation can be explained by uneven force distributions over non-spherical grit particles with lumpy grease deposits and variable curvature that effect motion traverse to flow, increase buoyancy and cause particle lift.

Abstract 12925: MICU Overflow Patients in the Cardiac Intensive Care Unit: Insights From the Critical Care Cardiology Trials Network Registry

Background: The cardiac intensive care unit (CICU) is designed to manage critically ill patients (pts) with acute cardiovascular (CV) conditions, but may be the site of care for pts with non-CV critical illness when medical ICU (MICU) beds are unavailable. Methods: The Critical Care Cardiology Trials Network (CCCTN) is a multicenter registry of consecutive admissions to CICUs in North America coordinated by the TIMI Study Group. Pts with no acute or major cardiac issues were designated as MICU overflow and were compared to those admitted with acute CV illness. A generalized mixed-effect regression model was used to adjust for age, sex, Sequential Organ Failure Assessment (SOFA) score and cardiac arrest while accounting for variability among centers. Results: Among 18,006 CICU admissions, 778 (4.3%) were MICU overflow, with a range of 0% to 26% among centers. MICU overflow rates trended lower over time (Fig-A) . In comparison to admissions with acute CV illness, MICU overflow patients were younger (60.0 vs 67.0 y, p<0.001) and more likely to be female (45.6 vs 36.7%, p<0.001). Comorbidities differed markedly between the 2 groups (Fig-B) . Presentation with cardiac arrest was more common among admissions with acute CV illness (12.9% vs 4.5%, p<0.001). MICU overflow admissions had higher SOFA scores than those with acute CV illness (5.0 vs 3.0, p<0.001). Resource utilization is shown in Fig-C . ICU LOS was similar (2.0 vs 2.2d, p=0.4). MICU overflow status was associated with a trend in CICU mortality (adj-OR 1.19, 95% CI 0.93-1.53, p=0.16) and significantly higher hospital mortality (adj-OR 1.69, 95% CI 1.36-1.73, p<0.001) (Fig-D) . Conclusions: MICU overflow pts constitute a meaningful number of admissions to CICUs. These pts have more multi-system disease, greater baseline organ dysfunction, and higher hospital mortality than pts with acute CV illness. These findings reinforce the need for multidisciplinary CICU teams with expertise in all facets of critical care.

Creep monitoring and parameters inversion methods for rock salt in extremely deep formation

When underground salt caverns are used for natural gas storage, the pressure difference between the inside and outside of the cavern will cause continuous creep deformation of the surrounding rock. Understanding the creep characteristics and constitutive model parameters of rock salt in actual formations is of great significance for guiding the construction and safe operation of gas storage facilities. In this paper, a creep contraction calculation model for slender cylindrical rock salt caverns was established firstly, based on the theory of complex variables and viscoelasticity. This model can calculate the radial displacement of the surrounding rock at any moment on the cross-section of the rock salt wellbore. Subsequently, two indirect monitoring methods for deep rock salt creep using the open hole section of the well were proposed based on this model, which involves using the cavern pressure change after wellhead closure and the liquid overflow rate after wellhead opening to indirectly reflect the deformation of underground rock salt. These two sets of field experiments can be used together to determine the values of the constitutive model parameters of rock salt creep under actual stress conditions. This theoretical framework was applied in the Ningjin Salt Cavern Gas Storage Project in China. Pressure monitoring was conducted for 150 days, and wellbore fluid overflow was measured for 45 h in a rock salt well at a depth close to 3000 m. The calculated results showed good agreement with the field monitoring data, and the parameters of the Burgers creep model for rock salt under actual conditions were determined. This demonstrates the strong feasibility of the monitoring method and the validity of the computational model. Finally, using the obtained creep parameters, a quantitative analysis of the creep contraction of the wellbore was performed considering factors such as internal pressure, in situ stress, and Poisson's ratio of the rock salt.

Improving secondary settling tanks performance by applying CFD models for design and operation

Abstract This study uses computational fluid dynamics (CFD) models for an improved performance of secondary settling tanks, taking as a case study the wastewater treatment plant (WWTP) of Souk-Ahras City, Northeastern Algeria. Unlike previous studies, which focused primarily on simulations of real-time clarifiers by independent measures, this study combines differentoperating criteria and geometric standards on clarifiers to estimate the ultimate capacity of secondary sedimentation tanks (SST). Numerical simulations were performed toassess the SST hydraulic performance under different conditions in order to (i) eliminate vortex zones; (ii) optimize the surface overflow rate (SOR) and predict sludge blanket height (SBH), and finally, (iii) estimate SST ultimate capacity. Based on the current configuration of the SST of Souk-Ahras WWTP, its hydraulic treatment capacity was found to be 49,000 m3/d. The results obtained, which were validated by field observations, showed that optimizing the different parameters yields a significantly improved SST performance. Furthermore, the tests consideredwere shown to be satisfactorily correlated with SOR. Validation using the receiver operating characteristic (ROC) curve analysis yielded anarea under curve (AUC) value of 90%, implying thereby a reasonably good performance. Indeed, optimization resulted in increased solidremoval efficiency and increased SOR to 1.4 m.h−1 (compared to 0.8 m.h−1 in literature) without overflow beyond the SBH.

Coupling physical selection with biological selection for the startup of a pilot-scale, continuous flow, aerobic granular sludge reactor without treatment interruption

This study removes two technical constraints for transitioning full-scale activated sludge infrastructure to continuous flow, aerobic granular sludge (AGS) facilities. The first of these is the loss of treatment capacity as a result of the rapid washout of flocculent sludge inventory and in turn the potential loss of nitrification during initial AGS reactor startup. The second is the physical selector design which currently is limited to either the complex sequencing batch reactor selection or sidestream hydrocyclones. Briefly, real wastewater data collected from this study suggested that by increasing the surface overflow rate (SOR) of an upflow clarifier to 10 m h −1, the clarifier can be taken advantage of as a physical selector to separate flocculant sludge from AGS. Redirecting the physical selector underflow and overflow sludge to the feast and famine zones of a treatment train, respectively, can create a biological selection that not only promotes AGS formation but also safeguards the effluent quality throughout the AGS reactor startup period. This study provides a novel concept for economically implementing continuous flow AGS within existing full-scale, continuous flow treatment trains.

Microwave-aided pyrolysis and fragmentation of tar-rich coal and rocks for in situ coal conversion and clean utilization

British Petroleum predicts that coal will account for the largest share in energy resources for power generation until 2040. The U.S. Energy Information Administration forecasts that coal will remain a key component of the country's national electricity portfolio at least until 2040. However, due to serious issues including high carbon emissions, environmental pollution, surface subsidence, resource wastage, and mining accidents associated with traditional coal mining and utilization patterns, international communities have called for the abandonment of coal use and adoption of renewable resources. To overcome the disadvantages, we proposed a novel approach for achieving in situ conversion and power generation using subsurface coal. An earthworm-shaped intelligent unmanned mining machine (IUMM) was designed to use high-power microwave energy to pulverize and pyrolyze coal into particles that can be used for power generation via chemical conversion. In this study, we used IUMM-based technology for in situ conversion and utilization of tar-rich coal and recovery of oil and gas from the coal. We quantified the pyrolysis efficiency of the tar-rich coal and the surrounding sandstone as well as the gas–liquid overflow rate of the coal under various high-power microwave irradiation conditions. The critical microwave energy threshold for discriminating tar-rich coal from the surrounding sandstone was determined, which will help to realise automatic pyrolysis of tar-rich coal by IUMM and minimise the damage caused by high-energy microwave radiation to the surrounding rock. This work aids in the production of cleaner energy, while ensuring energy security.

Struvite recovery efficiency using flocculation in batch and continuous settling systems for ammonia removal of mining wastewater.

An approach to remove ammonia from mining wastewater is to precipitate ammonia into struvite, and flocculation was proved to enhance settling of struvite flocs. But the current literature fails to consider flocculent properties of struvite flocs, and previous studies focused only on small volumes. This study evaluates the effect of ammonia concentration and height on removal efficiency of struvite flocs in a batch system and compares removal efficiency of struvite flocs between a batch and a pilot-scale continuous settling process to evaluate the potential of using flocculation to recover struvite crystals as a stand-alone method. Removal efficiency of struvite using flocculation is evaluated depending on depth in a batch system for two different ammonia concentrations (45 and 90 ppm) and in a continuous system for different flowrates. It is shown that a higher concentration promotes flocculation and enhances settling velocities of struvite flocs. The difference between the batch and the continuous processes for the same removal efficiency was significantly higher from what has been reported in the literature: in the continuous process, 89% of struvite flocs have been recovered with a surface overflow rate (SOR) of 1.8 m.h-1 , whereas, for the same height, the same efficiency corresponds to SOR = 9 m.h-1 in the batch process. The fragile nature of struvite flocs is potentially responsible for such a difference. PRACTITIONER POINTS: Settling velocities of struvite flocs are highly dependant on concentration and depth. Removal efficiency are considerably higher with a batch settling process for the same surface overflow rate. Flocculation enable 89% of struvite fines to be recovered in a continuous settling process with a SOR of 1.8 m.hs-1 .

Numerical Analysis of the Effect of the Vortex Finder on the Hydrocyclone’s Split Water Ratio and Separation Performance

Hydrocyclones are devices used in numerous areas of the chemical, food, and mineral industries to separate fine particles. A hydrocyclone with a diameter of d50 mm was modeled using the commercial Simcenter STAR-CCM+13 computational fluid dynamics (CFD) simulation package. The numerical methods confirmed the results of the different parameters, such as the properties of the volume fraction, based on CFD simulations. Reynolds Stress Model (RSM) and the combined technique of volume of fluid (VOF) and discrete element model (DEM) for water and air models were selected to evaluate semi-implicit pressure-linked equations and combine the momentum with continuity laws to obtain derivatives of the pressure. The targeted particle sizes were in a range of 8–100 microns for a dewatering application. The depth of the vortex finder was varied to 20 mm, 30 mm, and 35 mm to observe the effects of pressure drop and separation efficiency. The split water ratio increased toward a 50% split of overflow and underflow rates as the length of the vortex finder increased. It results in better particle separation when there is a high injection rate at the inlet. The tangential and axial velocities increased as the vortex finder length increased. As the depth of the vortex finder length increased, the time for particle re-entrainment into the underflow stream increased, and the separation efficiency improved.

Wastewater treatment plant serves as a potentially controllable source of microplastic: Association of microplastic removal and operational parameters and water quality data

Wastewater treatment plant (WWTP) has great potential to regulate microplastics (MPs) emissions, but few studies have focused on this subject. The present study performed a long-term investigation in a typically combined sewers WWTP. Compared to dry weather, rainfall contributed approximately 1.5 times more MPs to the inlet of the combined WWTP. The equalization tank served as a primary site for MPs' removal, with a 46.67-87.91% removal rate. Decreasing surface overflow rate (SOR) was an effective measure for improving MPs removal, and a suitable SOR was recommended at ~11 m 3 (d·m 2 ) -1 ) in the equalization tank. However, MPs' existing settling/rising velocity models failed to obtain a theoretical SOR. In cyclic activated sludge systems, reducing sludge wastage was proposed to facilitate the removal of MPs. As a result, outlet MPs could be reduced by an order of magnitude by adjusting operational parameters on rainy days. Our study highlighted the potential for WWTP to operate as a controlled source of MPs by altering the operational parameters. We also advocated exploiting the mechanisms of MPs' removal by operational parameters and finding an equilibrium between MPs' removal and activated sludge performance. • MPs in WWTP can be mitigated 90% by adjusting operational parameters on rainy days. • Decreasing the SOR (or raising the HRT) improve MPs' removal in equalization tank. • Models were incapable to predict MPs’ velocities, failing to obtain suitable SOR. • Reducing sludge wastage enhanced MPs' removal in the CASS. • Balance the MPs’ removal and the activated sludge’s performance was needed in CASS.

Development and Application of Urban Flood Prediction System for Smart Cities

To preemptively respond to urban flood disasters, a flood prediction system that provides a connection service with a smart city data hub was developed. The systems developed in this study provide real-time and predicted rainfall data, 1D and 2D flood prediction data, manhole-based flood prediction and warning information, and flood vulnerability index by administrative district. A one-dimensional analysis for the water depth and overflow amount of each manhole was calculated using the Storm Water Management Model (SWMM). A two-dimensional inundation analysis, the Two-Dimensional Inundation System (2DIS), which is capable of two-dimensional surface inundation analysis, was applied. The model can simulate surface flooding using the manhole overflow rate of the SWMM model. In the system, the flood prediction information was made based on the rainfall scenario, and the applied rainfall is 30-90 mm per hour, while the rainfall time distribution is Huff 3rd quartile. The propagation of flood conditions in the system can provide a five-stage (Safety, Attention, Caution, Alert, and Serious) scale depending on the water depth and surcharge conditions of the pipeline. The flood prediction model developed in this study was compared and verified with the existing flood survey data in the Dalseo Drainage Basin in 2002, and the model verification showed that the probability of flood detection (POD) was more than 80%.

Fine scale hydrologic modelling of bioretention using DRAINMOD-urban: Verifying performance across multiple systems

Urbanization causes fundamental shifts in hydrologic partitioning within watersheds, leading to excess runoff being quickly routed to nearby conveyances. This leads to a host of concerns, from flooding to water quality impairments. To combat these effects, bioretention systems are implemented to restore more natural hydrology in the urban environment. To better understand and predict the effectiveness of these interventions, there is a need for reliable hydrology models to assess the performance of bioretention cells prior to installation. DRAINMOD-Urban was recently developed to produce hydrographs with a high temporal resolution, showing substantial promise during initial testing. Unfortunately, the dataset originally used for testing was limited, having minimal occasions of overflow and only consisting of one bioretention location. To achieve a more robust analysis of the model, DRAINMOD-Urban was evaluated using two years of monitoring data for four bioretention cells in North Carolina. The modeled bioretention cells had variable media depths, surface storage volumes, site conditions, and propensity for overflow. DRAINMOD-Urban model parameters were calibrated for a Nash-Sutcliff efficiency (NSE) from 0.14 to 0.60 for drainage and from 0.49 to 0.89 for overflow across the sites using six months of monitoring data. Model validation confirmed these results, producing drainage and overflow hydrographs with accurate timing, duration, and a range of NSEs from 0.19 to 0.60 and from 0.49 to 0.81, respectively, across the four sites. Model performance varied across sites; high drainage and overflow rates are well predicted compared to extended low rates caused by clogging issues or small storms. This study highlights the potential of DRAINMOD-Urban in modeling bioretention hydrology at a fine temporal scale under varying design configurations.

Impacts of sea level rise on wave overtopping rates around the coast of England

There is unequivocal evidence that global sea levels are rising. It is therefore inevitable there will be socioeconomic impacts as a result of this. To aid mitigation, and the implementation of adaptation measures, it is vital the magnitude of the potential impact is quantified. Current approaches in the UK make simplifying assumptions regarding the relationship between present-day and future economic damage relating to coastal flood risk. The analysis undertaken here supports studies of an improved impact of sea level rise by providing national-scale estimates of changes in wave overtopping rates and flood defence overflow rates, as a result of different amounts of sea level rise. The analysis involves the application of components of an existing risk-based coastal flood risk analysis method. A subset of almost 600 flood defence assets around the country has been analysed for sea level rise rates up to 1 m. The resulting analysis shows that, on average, the wave overtopping rate increases by up to 150 times above present-day rates for lower return periods and by up to five times for higher return periods. This differential arises as a result of non-linearities in overtopping rates with increasing extreme sea levels.

An investigation into the use of acid treated sugar cane bagasse ash-based coagulants for water treatment

Abstract The aim of the study was to investigate the possibility to use acid treated sugarcane bagasse ash (SCBA) as a coagulant. The effect of type of acid, coagulant dose, time and pH on the coagulation characteristic were investigated. Synthetic turbid water was used for the tests. The coagulants were treated with H2SO4 (SSCBA) and HCl (HSCBA). A 6% m/v solid loading (S/L) of HSCBA reduced turbidity by 97.7% whilst an 8% m/v S/L of SSCBA reduced turbidity by 90.9%. Both coagulants exhibited hindered, transition and compression settling characteristics, however HSCBA had faster settling pattern. Turbidity reduction was best in the 6–10 pH range where there was over 90% turbidity reduction from an initial synthetic turbid water of 110 nephelometric turbidity units (NTU). Both coagulants were tested against natural highly turbid river water, and it was shown that only the HSCBA could reduce turbidity from 1,644 NTU to 2 NTU over 100 min. It was also shown that an overflow rate allowance of 0.01 cm/s could achieve 90% turbidity reduction using HSCBA when type 1 settling used for empirical calculations. The use of HSCBA was also shown to result in an insignificant amount of residual pH, Fe, Cu and Zn in the treated water. This therefore makes the use of HSCBA favorable in that it does not change the chemistry of the treated water.

Enhancing bioflocculation in high-rate activated sludge improves effluent quality yet increases sensitivity to surface overflow rate

High-rate activated sludge (HRAS) relies on good bioflocculation and subsequent solid-liquid separation to maximize the capture of organics. However, full-scale applications often suffer from poor and unpredictable effluent suspended solids (ESS). While the biological aspects of bioflocculation are thoroughly investigated, the effects of fines (settling velocity < 0.6 m3/m2/h), shear and surface overflow rate (SOR) are unclear. This work tackled the impact of fines, shear, and SOR on the ESS in absence of settleable influent solids. This was assessed on a full-scale HRAS step-feed (SF) and pilot-scale HRAS contact-stabilization (CS) configuration using batch settling tests, controlled clarifier experiments, and continuous operation of reactors. Fines contributed up to 25% of the ESS in the full-scale SF configuration. ESS decreased up to 30 mg TSS/L when bioflocculation was enhanced with the CS configuration. The feast-famine regime applied in CS promoted the production of high-quality extracellular polymeric substances (EPS). However, this resulted in a narrow and unfavorable settling velocity distribution, with 50% ± 5% of the sludge mass settling between 0.6 and 1.5 m3/m2/h, thus increasing sensitivity towards SOR changes. A low shear environment (20 s−1) before the clarifier for at least one min was enough to ensure the best possible settling velocity distribution, regardless of prior shear conditions. Overall, this paper provides a more complete view on the drivers of ESS in HRAS systems, creating the foundation for the design of effective HRAS clarifiers. Tangible recommendations are given on how to manage fines and establish the optimal settling velocity of the sludge.

Effects of high-power microwave irradiation on tar-rich coal for realising in situ pyrolysis, fragmentation, and low-carbon utilisation of tar-rich coal

Tar-rich coal was directly combusted during power generation, resulting in a huge waste of precious oil resources and a large amount of carbon emissions . The idea of intelligent unmanned mining machine (IUMM) for in-situ fluidised mining and conversion of tar-rich coal was proposed to solve the problems of traditional mining and utilisation methods, realise efficient utilisation of tar-rich coal, and achieve net-zero CO 2 emission. A key technology of IUMM is the pyrolysis and fragmentation of tar-rich coal by high-power microwave irradiation . In this study, we carried out experiments on the strength and microstructural changes of tar-rich coal under different microwave irradiation conditions using the high-power microwave irradiation testing system to explore the effects of microwave irradiation on tar-rich coal and provide a reference for the design of IUMM. The X-ray computed tomography was employed to observe and characterize the initiation, growth, connection, and spatial distribution of internal fractures of tar-rich coal under different microwave irradiation conditions. The quantitative relationship between the strength characteristics of tar-rich coal and microwave irradiation conditions was established. The results show that under a fixed microwave power or irradiation time, the overflow rate of coal gas and tar is linearly positively correlated with microwave energy E , and both the uniaxial compressive strength and brittleness of tar-rich coal have piecewise linear negative correlation with E . With the increase of E , the internal fractures grow and connect more, which are synchronised with the decrease of the uniaxial compressive strength and elastic modulus of the tar-rich coal. With equal E input, high-power microwave has a more significant effect on strength weakening, fracturing, and fragmentation of tar-rich coal. Our findings can be used for the subsequent implementation of in-situ pyrolysis and fragmentation technology of IUMM for realising the in-situ conversion, high-efficiency utilisation, and low carbon emissions of tar-rich coal.

Robotically assisted augmented reality system for identification of targeted lymph nodes in laparoscopic gynecological surgery: a first step toward the identification of sentinel node : Augmented reality in gynecological surgery.

To prove feasibility of multimodal and temporal fusion of laparoscopic images with preoperative computed tomography scans for a real-time in vivo-targeted lymph node (TLN) detection during minimally invasive pelvic lymphadenectomy and to validate and enable such guidance for safe and accurate sentinel lymph node dissection, including anatomical landmarks in an experimental model. A measurement campaign determined the most accurate tracking system (UR5-Cobot versus NDI Polaris). The subsequent interventions on two pigs consisted of an identification of artificial TLN and anatomical landmarks without and with augmented reality (AR) assistance. The AR overlay on target structures was quantitatively evaluated. The clinical relevance of our system was assessed via a questionnaire completed by experienced and trainee surgeons. An AR-based robotic assistance system that performed real-time multimodal and temporal fusion of laparoscopic images with preoperative medical images was developed and tested. It enabled the detection of TLN and their surrounding anatomical structures during pelvic lymphadenectomy. Accuracy of the CT overlay was > 90%, with overflow rates < 6%. When comparing AR to direct vision, we found that scores were significatively higher in AR for all target structures. AR aided both experienced surgeons and trainees, whether it was for TLN, ureter, or vessel identification. This computer-assisted system was reliable, safe, and accurate, and the present achievements represent a first step toward a clinical study.

Implementing machine learning to optimize the cost-benefit of urban water clarifier geometrics

Clarification basins are ubiquitous water treatment units applied across urban water systems. Diverse applications include stormwater systems, stabilization lagoons, equalization, storage and green infrastructure. Residence time (RT), surface overflow rate (SOR) and the Storm Water Management Model (SWMM) are readily implemented but are not formulated to optimize basin geometrics because transport dynamics remain unresolved. As a result, basin design yields high costs from hundreds of thousands to tens of million USD. Basin optimization and retrofits can benefit from more robust and efficient tools. More advanced methods such as computational fluid dynamics (CFD), while demonstrating benefits for resolving transport, can be complex and computationally expensive for routine applications. To provide stakeholders with an efficient and robust tool, this study develops a novel optimization framework for basin geometrics with machine learning (ML). This framework (1) leverages high-performance computing (HPC) and the predictive capability of CFD to provide artificial neural network (ANN) development and (2) integrates a trained ANN model with a hybrid evolutionary-gradient-based optimization algorithm through the ANN automatic differentiation (AD) functionality. ANN model results for particulate matter (PM) clarification demonstrate high predictive capability with a coefficient of determination (R2) of 0.998 on the test dataset. The ANN model for total PM clarification of three (3) heterodisperse particle size distributions (PSDs) also illustrates good performance (R2>0.986). The proposed framework was implemented for a basin and watershed loading conditions in Florida (USA), the ML basin designs yield substantially improved cost-effectiveness compared to common designs (square and circular basins) and RT-based design for all PSDs tested. To meet a presumptive regulatory criteria of 80% PM separation (widely adopted in the USA), the ML framework yields 4.7X to 8X lower cost than the common basin designs tested. Compared to the RT-based design, the ML design yields 5.6X to 83.5X cost reduction as a function of the finer, medium, and coarser PSDs. Furthermore, the proposed framework benefits from ANN’s high computational efficiency. Optimization of basin geometrics is performed in minutes on a laptop using the framework. The framework is a promising adjuvant tool for cost-effective and sustainable basin implementation across urban water systems.