High Surge Research Articles

Genomic Surveillance of SARS-CoV-2 in Malaysia during the Era of Endemic COVID-19.

On 5 May 2023, WHO declared the end of coronavirus disease 2019 (COVID-19) as a public health emergency of international concern. However, the risk of new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants causing rapid and high surges in cases and deaths remained. In Malaysia, five COVID-19 waves during the pandemic phase were well characterized, but similar studies focusing on the endemic phase were lacking. Hence, we retrieved 14,965 SARS-CoV-2 genomic sequences from the GISAID EpiCoV database for clade, lineage, and phylogenetic analysis in order to provide an insight into the population dynamics of SARS-CoV-2 that circulated in Malaysia from June 2022 to April 2023. The dominance of the Omicron variants was observed, and two new waves of infections driven by BA.5.2 and XBB.1, respectively, were detected. Data as of April 2023 also pointed to a possible eighth wave driven by XBB.1.9. Although new variants associated with higher transmissibility were behind the multiple surges, these subsequent waves had lower intensities as compared to the fourth and fifth waves. The on-going circulation and evolution of SARS-CoV-2 mean that COVID-19 still poses a serious threat, necessitating active genomic surveillance for early warning of potential new variants of concern.

Estimating Structural Damage to Mangrove Forests Using Airborne Lidar Imagery: Case Study of Damage Induced by the 2017 Hurricane Irma to Mangroves in the Florida Everglades, USA.

In September 2017, Hurricane Irma made landfall in South Florida, causing a great deal of damage to mangrove forests along the southwest coast. A combination of hurricane strength winds and high storm surge across the area resulted in canopy defoliation, broken branches, and downed trees. Evaluating changes in mangrove forest structure is significant, as a loss or change in mangrove forest structure can lead to loss in the ecosystems services that they provide. In this study, we used lidar remote sensing technology and field data to assess damage to the South Florida mangrove forests from Hurricane Irma. Lidar data provided an opportunity to investigate changes in mangrove forests using 3D high-resolution data to assess hurricane-induced changes at different tree structure levels. Using lidar data in conjunction with field observations, we were able to model aboveground necromass (AGN; standing dead trees) on a regional scale across the Shark River and Harney River within Everglades National Park. AGN estimates were higher in the mouth and downstream section of Shark River and higher in the downstream section of the Harney River, with higher impact observed in Shark River. Mean AGN estimates were 46 Mg/ha in Shark River and 38 Mg/ha in Harney River and an average loss of 29% in biomass, showing a significant damage when compared to other areas impacted by Hurricane Irma and previous disturbances in our study region.

Na3VMn0.5Ti0.5(PO4)3/C with active Na+ hopping sites for high-rate and durable sodium-ion batteries

This study established the carbon-coated Na3VMn0.5Ti0.5(PO4)3/C (NVMTP/C) as a high-energy cathode material of the NASICON family for next-generation sodium-ion batteries (SIBs). When subjected to electrochemical sodium storage testing, the NVMTP/C cathode provided a stable specific capacity of 160.3 mAh g-1 with three electron reactions (average working voltage ∼3.4 V) during the Na+ (de)insertion routine, achieving a superior energy output of 544 Wh kg−1 among the NASICON family of SIBs. Benefiting from the characteristic NASICON structure and established multiple redox couples, the cathode delivered excellent rate capability (82 mAh g-1 at 17 C, 1 C = 176 mAh g-1), in addition to excellent cycling permanence at low and high current surges (104 mAh g-1 after 500 cycles at 0.85 C and 84 mAh g-1 after 3000 cycles at 11.34 C, respectively). Computational studies based on first principle calculations and density of states (DoS) attributed the superior electrochemical properties of NVMTP/C cathode to its substantial Na+ hopping sites facilitating the unhindered multi-electron transfer reactions (V2+/3+, V3+/4+, Ti3+/4+, and V4+/5+) reversibly at their respective redox potentials. The detailed DoS analysis revealed that the varying electronic configuration due to the co-swapping of Ti and Mn significantly uplifts the electronic conductivity of the NVMTP/C cathode. Further calculation studies clearly indicate lower activation energy for active Na+ hopping and hence faster Na-diffusion thus suggesting that the present NVMTP/C cathode can have definite commercial prospects.

Statistical evaluation of stability margin of a multi-stage compressor with geometric variability using adaptive polynomial chaos-Kriging model

Compressed air energy storage systems must promptly adapt to power network demand fluctuations, necessitating a high surge margin in the compression system to ensure safety. It is challenging to completely eliminate blade geometric variations caused by limited machining precision, the important effects of which should be considered during aerodynamic shape design and production inspection. The present paper explores the uncertainty impact of geometric deviations on the stability margin of a multi-stage axial compressor at a low rotational speed. Initially, an adaptive polynomial chaos expansion-based universal Kriging model is introduced, and its superior response performance in addressing high-dimensional uncertainty quantification problems is validated through rigorous analytical and engineering tests. Then, this model is used to statistically evaluate the stability margin improvement (SMI) of the compressor due to the Gaussian and realistic geometric variabilities separately. The results show that the mean and standard deviation of SMI are −0.11% and 0.5% under the Gaussian geometric variability, while those are 0.33% and 0.39% under the realistic variability. For both the geometric variabilities, the stagger angle and maximum thickness deviations of the first-stage rotor are the most influential parameters controlling the uncertainty variations in the stability margin. Finally, the underlying impact mechanism of the influential geometric deviations is investigated. The variation in the stability margin caused by the geometric deviations primarily results from the alteration of inlet incidences, affecting the size of the tip leakage vortex blockage and boundary-layer separation regions near the blade tip of the first-stage rotor.

Design and implementation of a novel dust collector controller for powder production industry

Industries those work with powder either in production or processing always left a portion of industrial dust in the air. By releasing this air directly in the surrounding environment of the industry pollution occurs. Therefore air filtration system is mandatory in these industries and usually bag filter dust collector controller is used. To control and maintain the proper functionality of the bag filtration system PLC based control system or a modular control board is used. In this paper, a novel dust collector controller is designed which can be installed by any user without having any programming knowledge. The main control keys of the control board are the pulse duration and pulse interval which drive the solenoid valves to release air pressure on the filter bags sequentially. Pulse duration can be controlled in the range of 0.01-0.9 seconds and pulse interval can be varied in the range of 1-99 seconds to control 10 rows of pulse jet simultaneously connected with the solenoid valve. The Number of rows can be adjusted and expanded if required. Moreover, noiseless switching provides silent operational functionalities and switching durability as well as the addition of surge controller ensures a complete protection from any sudden high electrical surge. The finally developed prototype was tested in different industries and provides maximum operational efficiency, which can effectively control online bag filter dust collector to separate micro dust particles from the polluted air.

Probabilistic compound flood hazard analysis for coastal risk assessment: A case study in Charleston, South Carolina

Coastal communities are susceptible to flooding due to flood drivers such as high tides, surge, waves, rainfall, and river discharges. Recent hurricanes such as Harvey, Florence, and Ian brought devastating impacts from combinations of high rainfall and storm surge, highlighting the need for resilience and adaptation planning to consider compound flood events when evaluating options to reduce future flood risk. Flood risk assessments often focus on a single flood driver (e.g. storm surge) due to the complexity of accounting for compound flood drivers. However, neglecting these compound flood effects can grossly underestimate the total flood risk. A probabilistic compound flood hazard analysis considers all compound events that lead to flooding, estimates their joint probabilities, simulates the flood response, and applies a probabilistic computation technique to translate flood responses and probabilities into probabilistic flood maps (such as the 100-year flood map). Probabilistic flood maps based on compound events can be used to assess risk more accurately for current and future conditions, with and without additional adaptation measures. In this paper we present an example of a probabilistic compound flood hazard analysis for the city of Charleston, South Carolina, considering tide, surge, and rainfall, for both hurricane and non-hurricane events. Charleston is regularly confronted with compound flood events, which are expected to worsen with sea level rise and more frequent tropical storms. Starting with an initial set of over 1,000 synthetic compound events, selection techniques described in the paper led to a final set of 207 compound events. The fast compound flood model SFINCS simulated the flood response for each event and, using numerical integration, compound flood return-period maps were created for Charleston, under current and future sea level rise conditions.

0493 A new perspective on exploring the predictive factors of blood pressure reduction during CPAP treatment in OSA

Abstract Introduction The predictive factors of BP response to continuous positive airway pressure (CPAP) in obstructive sleep apnea (OSA) are still being explored. We aimed to assess the antihypertensive effect of CPAP considering the obstructive respiratory event-triggered BP surge profiles in 130 subjects with severe OSA and untreated hypertension. Methods Nocturnal BP was monitored continuously and synchronized with polysomnography. Event-triggered BP surge profiles were studied: BP surge as the value of event-related systolic BP elevation; BP index as the number of BP surge events of ≥10 mmHg per hour. Patients were then divided into two groups according to the median BP index (high and low BP surge groups) and assigned to 4 weeks of CPAP. Changes in BPs and plasma biomarkers were compared. After the initial evaluation, patients with a better BP response in the high BP surge group were then followed up for the second evaluation at 24 months. Results Overall, a modest decrease was observed in both office and asleep BPs at the 4-week follow-up; however, BPs dropped more markedly in patients in high BP surge group than those in low BP surge group, in both office systolic BP (SBP:5.3 mmHg vs.2.2 mmHg, P=.005) and diastolic (DBP:4.0mmHg vs.1.2 mmHg, P=.011), especially the asleep SBP (9.0mmHg vs.2.1 mmHg, P<.001). For 30 cases in the high BP surge group, optimal BP control was achieved in 60.0% of patients and BP < 140/90mmHg reached up to 83.3% after 24 months of CPAP. Linear regression revealed that BP index was significantly associated with BP decrease during CPAP treatment. Conclusion Our results suggest that high event-triggered BP surge was a sensitive predictor of BP response to CPAP in patients with severe OSA and hypertension. Support (if any)

New perspective on exploring the predictive factors of blood pressure reduction during CPAP treatment in people with severe OSA and hypertension: a prospective observational study

BackgroundThe predictive factors of blood pressure (BP) response to continuous positive airway pressure (CPAP) in obstructive sleep apnoea (OSA) are still being explored. We aimed to assess the antihypertensive effect...

Comprehensive Analysis and Experiment of Extreme Faults in MMC Based on IGCT

High voltage direct current voltage source converter (HVDC-VSC) technology is one of most important solutions for transmission of large-scale renewable sources. Modular multilevel converter (MMC) is one of the most popular topologies for HVDC-VSC system. The extreme faults affect the safety and reliability of MMC greatly. This paper gives comprehensive analysis and experiment of extreme faults in MMC based on integrated gate commutated thyristor (IGCT). Causes and characterization of the extreme faults are analyzed in detail. A new protection solution based on IGCT with controlled punch-through design (CP-IGCT) and fast recovery diode with high surge current capability (HS-FRD) is proposed. The surge current capability of HS-FRD is validated via experiment successfully. Theoretical calculation shows that the protection solution based on CP-IGCT and HS-FRD can help reduce the maximum fault current below 50% when the anode inductor is 0.8 μH in the extreme shoot-through fault. Test results show that the protection solution can realize the discharge of the DC capacitor below 4.5 kV in the extreme shoot-through fault. The maximum fault current in MMC based on IGCT is only about 600 kA while the maximum fault current in MMC based on insulated gate bipolar transistor (IGBT) is over 1100 kA. Explosion proof of CP-IGCT is validated during the tests, which is similar to that of the protection thyristor. However, IGBT can't guarantee the stability of the package and may cause severe safety problem. The failed CP-IGCT has the short circuit failure mode (SCFM) and can be used for bypass of the faulty MMC sub-module (MMC-SM). Via comparison, the proposed protection solution has lowest cost and complexity, as well as the highest safety.

Comparative Study of Clinical Severity and Biochemical Markers in Pre COVID-19 and COVID-19 Rhino-Orbito Cerebral Mucormycosis

In view of high surge of sinonasal mucormycosis cases after the second wave of covid 19, present study was planned to know and compare the clinical severity of the disease and also to better understand the difference in the biochemical markers during precovid and post covid period. This retrospective observational study included all cases of sinonasal mucormycosis which were treated in our institute from August 2012 to August 2021. Details of these cases were collected from hospital database system. Biochemical parameters included FBS, HbA1C, urine ketone bodies, blood pH and creatinine. Clinical severity score was measured using self-structured severity scoring system. We found that out of 74 cases treated in our hospital 28 cases were in pre covid period while 46 cases belonged to covid 19 period. Higher male predominance was seen during post covid period (76% vs. 60%). Urine ketone bodies were positive in 7% patients in precovid period compared to 26% in post-covid period. FBS and HbA1C were high approximately 80 and 90% patients respectively in both groups. Clinical severity was significantly high in post covid patients. The present study showed that in spite of similar biochemical profile. The severity of mucormycosis was high in covid positive patients. This study shows that Covid-19 is an independent high risk factor in mucormycosis patients.

China’s electric vehicle and climate ambitions jeopardized by surging critical material prices

The adoption of electric vehicles (EVs) on a large scale is crucial for meeting the desired climate commitments, where affordability plays a vital role. However, the expected surge in prices of lithium, cobalt, nickel, and manganese, four critical materials in EV batteries, could hinder EV uptake. To explore these impacts in the context of China, the world’s largest EV market, we expand and enrich an integrated assessment model. We find that under a high material cost surge scenario, EVs would account for 35% (2030) and 51% (2060) of the total number of vehicles in China, significantly lower than 49% (2030) and 67% (2060) share in the base-line, leading to a 28% increase in cumulative carbon emissions (2020-2060) from road transportation. While material recycling and technical battery innovation are effective long-term countermeasures, securing the supply chains of critical materials through international cooperation is highly recommended, given geopolitical and environmental fragilities.

Studying Dielectric Losses of Serially Combined Silicone Rubber and Epoxy Resin

High voltage outdoor insulation systems are conventionally ceramics and glass with several advantages, such as proven in the field, excellent dielectric properties, durability, and long life. However, they are heavy, attract vandals and break easily, and they can lose their dielectric properties easily when subjected to high voltage transients, arcing, and surges. To curb this, polymer insulators are used because they have excellent dielectric properties, such as those of ceramics and glass, with the added advantages that they do not break easily and recover their lost dielectric properties after any electrical transients. Therefore, this paper investigates the dielectric properties of polymeric materials – silicone rubber (SR) and epoxy resin (ER). Some SR samples were manufactured in the laboratory, and others were obtained from the industrial manufacturer. All the ER samples were manufactured in the laboratory. The dielectric measurements were performed with the Insulation Diagnostics System. Within the measured frequency ranges, the dielectric losses of SR manufactured industrially differ from the laboratory-manufactured specimens. This is due to filler materials in the industrially manufactured samples. For the case of serially connecting the SR and ER, there was a higher influence of dielectric loss of SR than the ER, with some remarkable dielectric losses at some frequencies.

A Novel Approach Using High Charging Voltage for the Restoration of Discarded Lead Acid Batteries

A lead acid battery is an old renewable battery that is usually discharged to deliver a high surge current to ignite a petrol-based engine. Nowadays, there are different improved versions of lead acid batteries that can deliver high energy densities with low maintenance costs. As the batteries are charged and discharged repeatedly over time, the amount of lead sulfate across the electrode plates grows, reducing the total surface areas of the plates and, thus, the rate of ionization between the electrolyte and the plate surfaces. The batteries then eventually come to the end of their service lives. Even with the improved versions, lead acid batteries are usually discarded at their retirement. However, if the retired batteries can be used for other purposes, the circular economy of the batteries can be improved significantly. It is therefore necessary to study the physical characteristics of the retired batteries and explore means of improving their charging and discharging capabilities. This paper presents research on improving the storage capability of retired lead acid batteries by applying different charging voltages across them. The results show that the electrode plates of the retired batteries become porous when a high charging voltage is applied, hence increasing the total surface area of the plate surfaces. The storage capability of the batteries is improved because the accumulated lead sulfate is removed from the electrode plates by the high charging voltage. As a result, the rate of ionization is increased, hence restoring the storing capability of the retired batteries to up to 71–89% of the original capacity rating.

Adaptive surge control of variable-mass unmanned surface vehicle based on sliding mode observation

To achieve the accurate control of the variable-mass unmanned surface vehicle (USV), this paper proposes an adaptive surge control method with uncertain variation in mass and draft. Aiming at the time-varying characteristics of the USV, the analytical expressions of mass and each hydrodynamic derivative are presented based on the draft and its higher-order terms as independent variables. The model uncertainty problem caused by quantities of nonlinear coupling terms related to the mass and draft is solved. For the high correlation between the motion state and the draft of the variable-mass USV, a sliding mode observer is designed to obtain the estimated varying mass and drat in real-time. The adaptive surge control algorithm of variable-mass USV is proposed, which can update its adaptive laws in real time based on the sliding mode observations. The overall stability of the control system is analyzed via the Lyapunov algorithm. Simulation experiments of several payload delivery missions are carried out. Results show that the proposed controller can achieve high precision surge control under typical missions for variable-mass USV, such as step variation and continuous payload change, and the control effect is remarkably better than the traditional control method.

1040. Comparative Surge Data on SARS CoV-2 Variants in a Rural Community – A Virtual Hospital Experience

Abstract Background UNC Health Blue Ridge is a nonprofit community teaching hospital with 145 staffed beds. The COVID-19 pandemic has challenged rural hospitals like ours with high occupancy and periodic surges. UNC Health Blue Ridge COVID Virtual Hospital (CVH) created a home monitoring program for enrolled patients with severe acute respiratory syndrome coronavirus 2 (SARS CoV-2) infection utilizing disease risk stratification and pulse oximeter readings to dictate nurse and clinician follow-up. We report raw data that compare surge levels in our community for the Alpha (B.1.1.7), Delta (B.1.617.2) and Omicron (B.1.1.529) surges. Methods From April 2020 to present, the CVH enrolled patients diagnosed with COVID-19 based on FDA approved PCR tests. For this abstract, we defined any surge as an outpatient CVH census of greater than 50 patients or an inpatient census of >10 patients. We defined the maximum intensity of the surge as >20% outpatient SARS CoV-2 positivity and a CVH census >100 patients or >20 inpatients with SARS CoV-2 infection. Results For the outpatient setting, days of surge and maximum intensity were 144 / 98 days for Alpha, 92 / 71 days for Delta, 74 / 47 days for Omicron, respectively. Average daily CVH admissions during surges were 17.7 for Alpha, 26.15 for Delta, and 27.15 for Omicron. Total emergency department (ED) and urgent care visits were 12,765 and 23,696 for Delta, and 9701 and 16102 for Omicron. In the inpatient setting, days of surge and maximum intensity days were 102/76 days for Delta and 78/48 days for Omicron. Our peak inpatient COVID-19 daily census was 51 and 50 patients for Delta and Omicron. Conclusion Our CVH has enrolled over 8700 patients, and our hospital has not been on diversion during the COVID-19 pandemic, unlike many surrounding hospital systems of similar size. More importantly, the CVH has helped create a sustainable model that gathers local data to aid predictive algorithms and facilitate proactive rather than reactive resource allocations. This virtual model can be adapted for multiple other health conditions in the outpatient setting to improve patient safety and quality care. Disclosures All Authors: No reported disclosures.

Design and Analysis of a DC Solid-State Circuit Breaker for Residential Energy Router Application

Energy routers act as an interface between the distribution network and electrical facilities, which meet the requirements of clean energy substitution and achieve the energy sharing and information transmission in the energy network. However, the protection of the dc load side of residential energy routers including interruption and isolation of short-circuit fault currents is vital for discussion. Since the traditional mechanical and hybrid circuit breakers for dc fault protection have the drawback of slow operation, a solid-state circuit breaker (SSCB) is an optimal solution for fast dc fault interruption. In this paper, a dc SSCB is proposed that uses an RCD + MOV snubber circuit, which is considered the best and most complete circuit used in common SSCBs. There are two main contributions in this paper: First, a dc SSCB is designed, which isolates both positive and negative terminals of a circuit and its working principle and operating modes along with the formulas for calculation of crucial time intervals, voltages, and currents along with the design procedure are provided. Second, a soft turn-on auxiliary is designed to prevent a high current surge caused by the capacitance difference between the source and the load. The experimental results demonstrate the proper performance of the topology and the validity of the findings.

Effect of short-time overheating in the morphology of primary carbides network in Nb and NbTi-modified HP stainless steels steam reforming tubes

Commercial bulk hydrogen is mainly produced in petrochemical steam reforming furnaces inside centrifugally cast Nb-modified HP austenitic stainless steels tubes, which operate at temperatures above 900 °C. In-service aging causes well known microstructural modifications such as the transformation of primary niobium carbides, NbC, into the G-phase (Ni16Nb6Si7). Unexpected operational problems, such as reduced feedstock flow may, in a few minutes, cause severe overheating. These short-time temperature surges, can lead tubes to premature failure often through the formation of large longitudinal cracks. Little is known about the integrity of the tubes that undergo a temperature surge without cracking. Thus, understanding the microstructural changes brought upon by these events becomes extremely important when assessing the reuse of these tubes. In the present work, by means of optical microscopy, scanning electron microscopy and transmission electron microscopy with energy dispersive X-ray spectroscopy, two Nb and NbTi-modified HP steels tubes, which cracked due to high temperature surges, were analyzed. Results show that insitu dissolution of the G-phase in the thermally affected regions causes this phase to be replaced by fine NbC or (NbTi)C precipitates. These microstructural transformations suffered by the tubes during the short-time overheating and cooling cycles are thus presented and discussed in terms of their practical consequences.

The impact of climate change on the storm surges of the Mediterranean Sea: Coastal sea level responses to deep depression atmospheric systems

The impact of climate change on the storm surges of the Mediterranean Sea: Coastal sea level responses to deep depression atmospheric systems

Micronutrients- The crucial dietary elements in Covid-19 pandemic: A review

The mutation of the SARS-CoV-2 virus, which cause person-to-person transmission, is the pivotal reason for the pandemic outbreak in the year 2020. Infection symptoms include fever, dry cough, lethargy, severe pneumonia, respiratory distress syndrome, and death. COVID-19 induces a systemic inflammatory reaction that impairs the immune system, commonly known as cytokine release syndrome. Pro-inflammatory cytokines and chemokines are abundant in COVID-19 sufferers' bodies. COVID-19 has a disproportionate impact on the elderly, both directly and through several comorbidities associated with age. Nutrition is without hesitation, a crucial factor in maintaining good health. Some nutrients are essential for the immune system's health and function, exhibiting synergistic actions in critical immune response steps. Vitamin D, C, and Zinc stand out among these nutrients because they have immunomodulatory properties and help to maintain physical tissue barriers. Considering the viability of the virus, nutrients that boost the immunity henceforth the severity of viral infections declines with improved prognosis become important. As a result, the purpose of this review is to provide a complete outline of vitamins D, C, and zinc's involvement during the immune response towards infection, and to enlighten their commensal action of maintaining physical barriers including integument and mucous membrane. Appropriate vitamin D, C, and zinc consumption may represent a feasible pharmacological intervention during the COVID-19 pandemic due to the high surge in population interaction and the commencement of inflammation.

Modeling the hydrodynamics of a tidal inlet during bay-side storms

Bay-side storms, defined here as storms with tracks on the landward side of barrier islands, may disturb the hydrodynamics of inner bays to a larger extent than on the ocean side. These storms are common in large-scale O(>100,000 m) estuarine systems and have the potential to modify the circulation in bays and within tidal inlets. Here, we provide an overview of the hydrodynamic response of a tidal inlet under forcings caused by bay-side storms and explore the role of waves in modulating the release of storm surge from the back-barrier regions into the ocean. A two-dimensional horizontal numerical model including wave-current interactions is calibrated and validated against field observations of water levels and depth-averaged velocities at Oregon Inlet, NC. The model is then used to investigate the effect of synthetic bay-side storms with varying wave conditions and water levels based on those generated by Hurricane Irene (2011), which is the strongest bay-side storm to hit the Outer Banks of North Carolina in the last two decades. Effect of timing of the peak storm surge during the ebb and flood phases of the tide is also explored.Results from synthetic storms indicate that, during bay-side storms, the water level gradient along the inlet favors ebbing flows regardless of the timing of the storms relative to tidal phase. These results suggest that waves might be responsible for any influx of volume to the bay during high bay-side surge events. Wave blocking effects were found to be stronger along the ebb shoal and only reached the flood delta when bay water levels were nearly the same as the ocean water levels. Reduction of currents by waves in the inlet have the potential to extend the duration of the inundation period in the back barrier region. Bay-side storms also caused flux enhancement over inlet shoals and channels in the flood delta, which could have implications for circulation patterns as well as the morphodynamics of the system.