Search Results (52)

This study investigates the certification outcomes of intermediate-level ICs in The National Fire Service Academy in South Korea through a comprehensive quantitative analysis of their evaluated competencies. Using assessment data from 141 candidates collected from 2022 to 2024, we examine how scores on six higher-order competencies—comprising 35 sub-competencies—influence pass or fail results. Descriptive statistics, correlation analysis, logistic regression (a statistical model for binary outcomes), random forest modeling (an ensemble decision-tree machine-learning method), and principal component analysis (PCA; a dimensionality reduction technique) were applied to identify significant predictors of certification success. Visualization techniques, including heatmaps, box plots, and importance bar charts, were used to illustrate performance gaps between successful and unsuccessful candidates. Results indicate that competencies related to decision-making under pressure and crisis leadership most strongly correlate with positive outcomes. Furthermore, unsupervised clustering analysis (a data-driven grouping method) revealed distinctive performance patterns among candidates. These findings suggest that current evaluation frameworks effectively differentiate command readiness but also highlight specific skill domains that may require enhanced instructional focus. The study offers practical implications for fire training academies, policymakers, and certification bodies, particularly in refining curriculum design, competency benchmarks, and evaluation criteria to improve fireground leadership training and assessment standards. Full article

The radioisotopic dating of five stratigraphic levels within the Permian succession of the Kuznetsk Coal Basin refined the ages of the corresponding stratigraphic units and, for the first time, enabled their direct correlation with the International Chronostratigraphic Chart, 2024. The analysis revealed significant discrepancies between the updated ages and the previously accepted regional scheme (1982–1996). A comparison of regional stratigraphic units’ durations with estimated coal and siliciclastic sediment accumulation rates indicated that the early Permian contains the most prolonged stratigraphic hiatuses. The updated stratigraphic framework enabled re-evaluating the temporal sequence of regional sedimentological, volcano–tectonic and biotic events, allowing for more accurate comparison with the global record. Palaeoclimate reconstructions indicated that during the early Permian, the Kuznetsk Basin was characterised by a relatively warm, humid, and aseasonal climate, consistent with its mid-latitude position during the Late Palaeozoic Ice Age. In contrast, the middle-to-late Permian shows a transition to a temperate, moderately humid climate with pronounced seasonality, differing from the warmhouse conditions of low-latitude palaeoequatorial regions. The latest Lopingian reveals a distinct trend toward increasing dryness, consistent with global palaeoclimate signals associated with the end-Permian crisis. Full article

Sea ice concentration (SIC) monitoring in the Arctic using microwave radiometer data is a well-established method with numerous published accuracy studies. For the Baltic Sea, accuracy studies have not yet been conducted. In this study, we evaluated five different SIC products over the Baltic Sea using MODIS (250 m) and Sentinel-2 (10 m) open water–sea ice classification charts. The selected SIC products represented different SIC algorithm types, e.g., climate data records and near-real-time products. The one-to-one linear agreement between the radiometer SIC dataset and the MODIS/Sentinel-2 SIC was always quite poor; the slope of the linear regression was from 0.40 to 0.77 and the coefficient of determination was from 0.26 to 0.80. The standard deviation of the difference was large and varied from 15.5% to 26.8%. A common feature was the typical underestimation of the MODIS/Sentinel-2 SIC at large SIC values (SIC > 60%) and overestimation at small SIC values (SIC < 40%). None of the SIC products performed well over the Baltic Sea ice, and they should be used with care in Baltic Sea ice monitoring and studies. Full article

The objective of this paper was to establish a comprehensive methodology for the optimized design of propellers for ice-class vessels, aiming to enhance hydrodynamic efficiency while ensuring structural integrity. This paper begins by introducing a novel approach for calculating blade stress, which takes into account both extreme ice loads and hydrodynamic loads, to be utilized in the propeller strength design process. Subsequently, a backpropagation (BP) neural network model was developed based on the data obtained from B-series propeller charts and integrated with a genetic algorithm to achieve a preliminary optimized design of the propeller’s hydrodynamic performance. To illustrate the application of this methodology, a case study of an ice-breaking tug propeller design is presented, detailing the optimization design process, including the preliminary, intermediate, and final design stages. The study also addresses key aspects such as geometric parameterization, the selection of optimization variables, the implementation of optimization algorithms, and the balance of multi-objective trade-offs. The proposed design approach can serve as a valuable reference for the practical engineering design of propellers for ice-class vessels, providing a systematic framework for achieving optimal performance in challenging operating conditions. Full article

The Hudson Bay seasonal sea ice record has been well known since the advent of satellite reconnaissance, with a continuous record since 1971. To extend the record to earlier decades, a thermal variability framework is used with the surface temperature climatological records from four climate stations along the Hudson Bay shoreline: Churchill, Manitoba; Kuujjurapik, Quebec; Inukjuak, Quebec; and Coral Harbour, Nunavut. The day-to-day surface temperature variation for the minimum temperature of the day was found to be well correlated to the known seasonal sea ice distribution in the Bay. The sea ice/thermal variability relationship was able to reproduce the existing sea ice record (the average breakup and freeze-up dates for the Bay) largely within the error limits of the sea ice data (1 week), as well as filling in some gaps in the existing sea ice record. The breakup dates, freeze-up dates, and ice-free season lengths were generated for the period of 1922 to 1970, with varying degrees of confidence, adding close to 50 years to the sea ice record. Key periods in the spring and fall were found to be critical, signaling the time when the changes in the sea conditions are first notable in the temperature variability record, often well in advance of the 5/10th ice coverage used for the sea ice record derived from ice charts. These key periods in advance of the breakup and freeze-up could be potentially used, in season, as a predictor for navigation. The results are suggestive of a fundamental change in the nature of the breakup (faster) and freeze-up (longer) in recent years. Full article

The temporal and spatial variation in seasonal sea ice in Hudson Strait is examined using time series and spatial clustering analyses. For the period from 1971 to 2018, a time series of sea ice breakup and freeze-up dates and ice-free season length at twenty-four grid points were generated from sea ice charts derived from satellite and other data. These data were analyzed temporally and spatially. The temporal analyses indicated an unambiguous response to a warming climate with statistically significant earlier breakup dates, later freeze-up dates, and longer ice-free seasons, that were statistically linked to coincident regional surface air temperatures. The rate of change in freeze-up dates and ice-free season length was particularly strong in the early 2000s and less so in the 2010s. There was evidence that breakup date behaviour was not only coincident with regional temperatures but likely with temperature and ice conditions of the previous year. Later freeze-up dates were directly linked to earlier breakup dates using detrended time series. Spatial clustering analysis on the Hudson Strait gridded sea ice data revealed distinctive signatures for Ungava Bay, Frobisher Bay, and for grid points close to the shore and a clear linkage to the underlying circulation of Hudson Strait. Full article

Exploring the interface of environmental sustainability and civil infrastructure development, this study introduces waste butter (WB), a byproduct of animal fat processing, as a novel bio-modifier in asphalt production. This approach not only recycles animal waste but also charts a course for sustainable infrastructural development, contributing to a reduced environmental impact and promoting circular economy practices. The experiments incorporated varying WB concentrations (e.g., 3%, 6%, and 9% by weight of binder) into standard AP-5 asphalt, employing advanced analytical tools for comprehensive characterization. These included thin-layer chromatography–flame ionization detection (TLC-FID), Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and Differential Scanning Calorimetry (DSC). The critical properties of the asphalt blends, such as penetration, softening point, viscosity, ductility, rutting factor (Dynamic Shear Rheometer), and thermal susceptibility (Penetration Index, Penetration–Viscosity Number), were assessed. FT-IR analysis indicated negligible chemical alteration with WB addition, suggesting predominantly physical interactions. TLC-FID showed a decrease in aromatic and asphaltene components but an increase in resin content, highlighting the influence of WB’s fatty acids on the asphalt’s chemical balance. The colloidal instability index (I_C) confirmed enhanced stability due to WB’s high resin concentration. Meanwhile, SEM analysis revealed microstructural improvements with WB, enhancing binder compatibility. TGA demonstrated that even a minimal 3 wt. % WB addition significantly improved thermal stability, while the DSC results pointed to improved low-temperature performance, reducing brittleness in cold conditions. Rheologically, WB incorporation resulted in increased penetration and ductility, balanced by decreased viscosity and softening point, thereby demonstrating its multi-faceted utility. Thermal susceptibility tests emphasized WB’s effectiveness in cold environments, with further evaluation needed at higher temperatures. The DSR findings necessitate careful WB calibration to meet Superpave rutting standards. In conclusion, this research positions waste butter as a superior, environmentally aligned bio-additive for asphalt blends, contributing significantly to eco-friendly civil engineering practices by repurposing animal-derived waste. Full article

Thin ice with a thickness of less than half a meter produces strong salt and heat fluxes which affect deep water circulation and weather in the polar oceans. The identification of thin ice areas is essential for ship navigation. We have developed thin ice detection algorithms for the AMSR2 and FY-3C MWRI radiometer data over the Arctic Ocean. Thin ice (<20 cm) is detected based on the classification of the H-polarization 89–36-GHz gradient ratio (GR8936H) and the 36-GHz polarization ratio (PR36) signatures with a linear discriminant analysis (LDA) and thick ice restoration with GR3610H. The brightness temperature ($T_B$) data are corrected for the atmospheric effects following an EUMETSAT OSI SAF correction method in sea ice concentration retrieval algorithms. The thin ice detection algorithms were trained and validated using MODIS ice thickness charts covering the Barents and Kara Seas. Thin ice detection is applied to swath $T_B$ datasets and the swath charts are compiled into a daily thin ice chart using 10 km pixel size for AMSR2 and 20 km for MWRI. On average, the likelihood of misclassifying thick ice as thin in the ATIDA2 daily charts is 7.0% and 42% for reverse misclassification. For the MWRI chart, these accuracy figures are 4% and 53%. A comparison of the MWRI chart to the AMSR2 chart showed a very high match (98%) for the thick ice class with SIC > 90% but only a 53% match for the thin ice class. These accuracy disagreements are due to the much coarser resolution of MWRI, which gives larger spatial averaging of $T_B$ signatures, and thus, less detection of thin ice. The comparison of the AMSR2 and MWRI charts with the SMOS sea ice thickness chart showed a rough match in the thin ice versus thick ice classification. The AMSR2 and MWRI daily thin ice charts aim to complement SAR data for various sea ice classification tasks. Full article

Over the past few years, the effects of global warming have become more pronounced, particularly with the melting of the polar ice caps. This has led to an increase in sea levels, which poses a threat of flooding to coastal cities and islands. Furthermore, monitoring and analyzing changes in water levels has proven effective for predicting natural disasters caused by the rising sea levels. One vital factor in understanding the impact of global warming is the sea surface height (SSH). Measuring the SSH can provide valuable information about changes in ocean levels. This study used data from the Jason 2 altimetry radar satellite, which provided 36 cycle periods per year, to investigate the water heights around the Hawaiian Islands in 2019. To accurately evaluate the water height variations, a specific area near the Pacific Ocean close to the Hawaiian Islands was selected. By analyzing the collected satellite data, a chart of water heights was generated, which showed an overall increase in the height over one year. This analysis provided evidence of changing ocean levels in the region, highlighting the urgency of addressing the potential threats faced by coastal communities. This study also explored several factors that contribute to water height variations, such as the sea surface temperature, precipitation, and sea surface pressure in the Google Earth Engine cloud-based platform. Algorithms, including MLP and XGBOOST, were used to model the water height within the specified range. The results showed that the XGBOOST algorithm was superior in accurately predicting the water height, with an impressive R-squared value of 0.95. In comparison, the MLP algorithm achieved an R-squared value of 0.92. This study shows that advanced machine learning techniques are effective in understanding and modeling the complex changes in the water height due to climate change. This information can help policymakers and local authorities make informed decisions and create strategies to protect coastal cities and islands from the growing threats of rising sea levels. Taking proactive measures is crucial in reducing the risks posed by more frequent and severe natural disasters caused by global warming. Full article

The Laney p′ control chart is a new type of attribute control chart that can be applied in situations where the process exhibits either overdispersion or underdispersion. While it has gained acceptance in the industry, there is still limited knowledge about its effectiveness in detecting process variation. It is well known that before applying a control chart, understanding its performance is crucial, especially when the parameters of the control chart need to be estimated from historical data. In this study, we used simulations to investigate the ability of the Laney p′ control chart to detect process variations when the parameters are estimated. We designed appropriate experiments to assess the impact of overdispersion on the average run length (ARL) performance. In this study, we assumed that the overdispersion comes from the variation in the mean fraction nonconforming of each sample. The mean value varies according to a uniform distribution. This study evaluated the performance of the Laney $p^{\prime }$ control chart using the average of the ARL (AARL) and the standard deviation of the ARL (SDARL). Additionally, real-world data were utilized to illustrate the practical applications of the Laney $p^{\prime }$ control chart in the PCB and IC substrate industries. The research findings can serve as valuable guidance for practical implementation. Full article

Background: Anatomic complications of the ureteroenteric anastomosis in ileal conduit (IC) cause significant morbidity in patients post-cystectomy and cystoprostatectomy. The Bricker technique has a perceived disadvantage of increased risk for stricture, whereas the Wallace technique runs the risk for ureteral malignancy affecting both ureteric ends, and bilateral ureteric obstruction from a stone lodged at the anastomosis. Methods: We aimed to evaluate the safety, efficacy, and stricture rate of a novel hybrid ureteroenteric anastomosis technique. We compared these outcomes to the Bricker and Wallace anastomosis techniques for IC urinary diversion (ICUD). We performed a retrospective chart review of patients who had undergone ICUD after cystectomy for bladder cancer from 2011 to 2016. Patients were categorized into groups undergoing the Bricker, Wallace, and hybrid ureteroanastomosic techniques. Strictures were identified during clinical follow-up or hospital presentations with complications. Results: We identified 68 patients suitable for inclusion. They were separated by Bricker, Wallace, and hybrid anastomosis techniques, with 19 (27.9%), 20 (29.4%), and 29 (42.6%) patients, respectively. Ureteroenteric anastomotic strictures occurred in 9 patients (5 Bricker, 3 Wallace, 1 hybrid). This difference in stricture rates for Bricker versus hybrid (26.3% vs. 3.4%; OR, 10 [95% CI, 1.1 to 121.1]; = 0.02) was significant but was comparable for Wallace versus hybrid (15.0% vs. 3.4%; OR, 4.9 [0.7 to 66.0]; = 0.15) and for Bricker versus Wallace (26.3% vs. 15.0%; OR, 2 [0.4 to 8.6]; = 0.87). 15 patients (51%) in the hybrid group required oral antibiotics for a symptomatic urinary tract infection compared with 4 (21%) with Bricker and 8 (40%) with Wallace ( = 0.10). Median post-cystectomy follow-up and stricture formation time were 16 months (IQR, 4–36) and 9 months (7–32), respectively. Conclusion: The hybrid technique is a safe and efficacious alternative to the Bricker and Wallace anastomoses. It carries with it a risk for urinary tract infection that is eclipsed by substantially lowered rates of ureteric strictures requiring intervention while maintaining the advantage of separating the two ureters. Full article

Bitumen’s self-healing capability is critical to the bitumen industry’s sustainable development. This work attempts to examine the self-healing property and fatigue behavior of bitumen using waste cooking oil (WCO) and polyphosphoric acid (PPA) in bitumen modification. Different components of WCO were mixed with PPA and bitumen for the initial modification. The linear amplitude sweep (LAS) test was used to evaluate the fatigue behavior of the modified bitumen. To assess the extent of bitumen healing after a fatigue-healing test, evaluation indicators, including fatigue life recovery (FLR), modulus recovery (MR), and dissipated energy recovery (DER), were selected. Meanwhile, a radar chart was used to analyze the integrated performance of WCO/PPA (WP)-modified bitumen. Lastly, the SARA fractions were separated from the bitumen to evaluate the modification mechanism. It was observed that the inclusion of PPA and WCO enhanced fatigue behavior. For 2% PPA and an intermediate component (IC) of WCO, the fatigue life of the LAS prediction model showed extreme values, with an increase of 669% over virgin bitumen. Regardless of the PPA concentration, a considerable increase in FLR, MR, and DER was seen in the bitumen processed with IC compared to virgin bitumen. Additionally, as the healing time was extended, the increment in the virgin bitumen’s healing indicators was higher than that of the modified bitumen. SARA results indicated that adding PPA changes the bitumen from a soluble state to a gel state. An innovative approach has been proposed to promote sustainable development within the bitumen industry. Full article

The temporal and spatial variation in seasonal sea ice in Arctic Bay, Nunavut, are examined using time series and spatial clustering analyses. For the period of 1971 to 2018, a time series of sea ice break-up, and freeze-up, dates and ice-free season length at nine grid points are generated from sea ice charts derived from satellites and other data. These data are analysed temporally and spatially. The temporal analyses indicate an unambiguous response to a warming climate with statistically significant earlier break-up dates, later freeze-up dates, and longer ice-free seasons with clear statistically significant linkages to local air temperature. The rate of change in freeze-up dates and ice-free season length was particularly strong in the early 2000s and less in the 2010s. Spatial clustering analysis indicated a roughly linear pathway of south to north behaviour, following the contours of the bay with the exception of modified behaviour for landfast sea ice near the hamlet of Arctic Bay. The temporal analysis confirms and expands upon an earlier time series analysis of local seasonal sea ice. The spatial analysis indicates that while the ice-free season is increasing, it does not provide clear evidence that there has been a regime change in the seasonal characteristics of how sea ice forms and melts each year. Full article

The use of inhaled corticosteroids (ICS) for the maintenance of bronchodilator treatment in patients with chronic obstructive pulmonary disease (COPD) is controversial. While some patients achieve clinical benefits, such as fewer exacerbations and improved symptoms, others do not, and some experience undesired side effects, such as pneumonia. Thus, we reviewed the evidence related to predictors of ICS therapy treatment response in patients with COPD. The first priority clinical markers when considering the efficacy of ICS are type 2 inflammatory biomarkers, followed by a history of suspected asthma and recurrent exacerbations. It is also necessary to consider any potential infection risk associated with ICS, and several risk factors for pneumonia when using ICS have been clarified in recent years. In this article, based on the evidence supporting the selection of ICS for COPD, we propose an ICS composite that can be added to the COPD (ICO) chart for use in clinical practice. The chart divided the type 2 biomarkers into three ranges and provided recommendations (recommend, consider, and against) by combining the history of suspected asthma, history of exacerbations, and risk of infection. Full article

Oceanographic and ice conditions in the region of Spitsbergen Bank in the Barents Sea were investigated in research cruises of the “Polarsyssel” in 2017–2019. Trajectories of ice drift were constructed using GPS data of the buoys deployed on the floes in the research cruises. The duration of the ice season in the region was analyzed using ice charts. The air temperature and wind velocities were analyzed using the data of meteorological stations on Bear Island and Hopen Island. Fieldwork on drifting ice showed the existence of thick consolidated floes with drafts up to 8 m, which were identified as completely consolidated sea ice ridges. The presence of such floes is dangerous for winter navigation along Spitsbergen Bank. A model of thermodynamic consolidation of ice ridges was formulated to investigate the thermodynamic evolution of ice ridges. The observed air and sea water temperatures were used in the boundary conditions on top and bottom surfaces of sea ice rubble. It was shown that the regular interaction of sea ice rubble with Atlantic and Arctic waters in the region of Spitsbergen Bank leads to almost complete consolidation of the ice rubble with an initial macro-porosity 0.2 for 150 days. Full article