Hazardous Areas Research Articles

Risk factors for suspected pulmonary embolism in children: Complication of Mycoplasma pneumoniae pneumonia

PurposePulmonary embolism (PE) is not a rare complication of Mycoplasma pneumoniae pneumonia (MPP) in children. We sought to determine the incidence of PE in children with MPP who underwent clinically indicated CT pulmonary angiography (CTPA) and to evaluate the risk factors for PE. MethodsAll 106 children with MPP who were clinically suspected of having PE and who underwent CTPA were retrospectively enrolled from June 2018 to December 2021. The clinical features, laboratory data, and radiological parameters were recorded (e.g., lung consolidation involved and the Qanadli score). A Cox proportional hazards model and area under the receiver operating characteristic (ROC) curve were used to evaluate the risk factors and prognostic discriminatory capacity for PE. ResultsPE was detected in 26 of 106 (24.5 %) children (mean age, 6.2 years ± 3.3 years; 53 boys). Sixteen of the 26 (61.5 %) children with PE were boys. The mean age of the children with PE was 8.1 ± 2.9 years, and the mean Qanadli score was 15.3 ± 10.2. Children with PE had higher D-dimer levels (9.3 ± 7.1 mg/Lvs. 3.6 ± 3.8 mg/L) and a greater frequency of lung lobe consolidation (25 (96.2 %) vs. 64 (80.0 %)) (all P < 0.05). For children with MPP, age (hazard ratio (HR) = 1.96 (95 % CI1.04, 3.71; P = 0.037), D-dimer level (HR = 1.52, 95 % CI: 1.03, 2.24; P = 0.029), and bilateral lung consolidation (HR = 2.41, 95 % CI: 1.03, 5.58; P = 0.043) were found to be independent predictors of PE. ConclusionClinical and CT radiological predictors could be used to predict PE in children with MPP. The use of risk factor assessment as a tool has the potential to guide more appropriate use of CTPA in children.

Compound wind and rainfall extremes: Drivers and future changes over the UK and Ireland

The co-occurrence of wind and rainfall extremes can yield larger impacts than when either hazard occurs in isolation. This study assesses compound extremes produced by Extra-tropical cyclones (ETCs) during winter from two perspectives. Firstly, we assess ETCs with extreme footprints of wind and rainfall; footprint severity is measured using the wind severity index (WSI) and rain severity index (RSI) which account for the intensity, duration, and area of either hazard. Secondly, we assess local co-occurrences of 6-hourly wind and rainfall extremes within ETCs. We quantify the likelihood of compound extremes in these two perspectives and characterise a number of their drivers (jet stream, cyclone tracks, and fronts) in control (1981–2000) and future (2060–2081, RCP8.5) climate simulations from a 12-member ensemble of local convection-permitting 2.2 km climate projections over the UK and Ireland. Simulations indicate an increased probability of ETCs producing extremely severe WSI and RSI in the same storm in the future, occurring 3.6 times more frequently (every 5 years compared to every 18 years in the control). This frequency increase is mainly driven by increased rainfall intensities, pointing to a predominantly thermodynamic driver. However, future winds also increase alongside a strengthened jet stream, while a southward displaced jet and cyclone track in these events leads to a dynamically-enhanced increase in temperature. This intensifies rainfall in line with Clausius-Clapeyron, and potentially wind speeds due to additional latent heat energy. Future simulations also indicate an increase in the land area experiencing locally co-occurring wind and rainfall extremes; largely explained by increased rainfall within warm and cold fronts, although the relative increase is highest near cold fronts suggesting increased convective activity. These locally co-occurring extremes are more likely in storms with severe WSI and RSI, but not exclusively so as local co-occurrence requires the coincidence of separate drivers within ETCs. Overall, our results reveal many contributing factors to compound wind and rainfall extremes and their future changes. Further work is needed to understand the uncertainty in the future response by sampling additional climate models.

Quantitative classification of equipment protection level in concept of zone classification with downtime of protective measures

Handling flammable materials has a risk that can create explosive atmosphere. Such locations are classified as hazardous area, depending on the frequency and volume of explosive atmospheres. General electrical equipment is prohibited in the hazardous area and explosion protected equipment is used. These are the spatial isolation of ignition sources within the fire triangle, but even time isolation can prevent explosion hazards as well. It is proposed a method to classify zones from the calculation of downtime of protective measures based on failure rates and repair times of protective measures related to ventilation in explosive gas atmospheres with the Functional Safety under the time isolation concept. On the other hand, according to International Electrotechnical Commission (IEC) System for Certification to Standards Relating to Equipment for Use in Explosive Atmospheres, explosion protected equipment was also classified as an Equipment Protection Level, "EPL". The EPL should be selected according to the risk of the hazardous area. However, in IEC60079–14:2013, users can choose any EPL according to their risk assessment. In this paper, we clarify the quantitative risk difference of EPLs with expansion the idea of classifying hazardous area from the downtime of protective measures and introduce a means to quantitatively classify the EPL of equipment in an explosive gas atmosphere.

Investigation on a mobile fire extinguishing approach using liquid carbon dioxide as inert medium for underground mine.

Injecting carbon dioxide is the most effective means of preventing and extinguishing fires in sealing hazardous areas, but the traditional method slowly and remotely injects carbon dioxide gas into the well after gasification on the ground, which is dependent on the complete mine pipe network without cooling effect. To inject liquid directly from the tank with vacuum interlayer and heat insulating powder for rapid inerting and cooling, a new approach using track mobile platform to go deep into the underground mine disaster area is proposed, so the liquid can be delivered to the nozzle at the end of DN40 large diameter pipe, and the continuous gasification jet can be realized. The experimental results show that: (1) The liquid volume in a tank of vacuum degree within 2.0 Pa and 200 mm interlayer reduced no more than 15.5% after 48 days; (2) Taking the pressure in the tank as the power source, because of environmental differences inside and outside the pipe after 100 m pressure holding delivery, the physical form of liquid and gas could be converted instantly; (3) The continuous discharge time without ice blocking for a tank full of 2 m3 liquid was about 10.5 min under 25 L dual mode nitrogen pressurization, which is 1/12 of injection time after ground gasification; (4) Based on the temperature decrease trend measured at different positions, the cooling characteristics on liquid gasification jet path are quantified, and the calculation formula of temperature changing with time on the center line of liquid gasification jet is obtained. Through this new approach, the integration of vacuum insulated storage, safe mobile transportation, and continuous and rapid release with large flow can be achieved for the liquid carbon dioxide.

Indoor space risk assessment based on Co-analysis strategy in split room air conditioning

The use of environmentally friendly hydrocarbon refrigerants in air conditioning systems is being promoted worldwide as a proactive measure to combat global warming and ozone depletion. A comprehensive analysis of hydrocarbon refrigerant leakage and the resulting fire risk is essential for split room air conditioning (SRAC) systems. The study presents a novel Co-analysis strategy that integrates the operation of SRAC systems with the assessment of indoor space fire risk. Experiments involving the leakage and diffusion of R-290 in SRAC system have been conducted to substantiate the validity of the Co-analysis strategy. This model is used to analyze the dynamic parameters of leakage and distribution patterns of hazardous areas within the SRAC indoor unit. The study considers various leakage hole sizes (1 mm, 2 mm, 3 mm) under both cooling and heating operating modes. The results show the leaking refrigerant flow rate presents different attenuation types under cooling and heating modes. When the leakage hole diameter is less than 2 mm in the cooling mode, the concentration of R-290 in the space is below 50 % lower flammable limit. The comprehensive fire risk probability of the R-290 indoor unit is 1.0 × 10−11∼5.0 × 10−10 for the cooling model and 1.0 × 10−11∼9.0 × 10−10 for the heating model. Effective methodologies for mitigating risks and optimizing the system are also proposed. Based on the Co-analysis strategy, this study presents a scientifically grounded assessment of the fire risk associated with air conditioning uses flammable refrigerants inside buildings. The strategy aims to enhance building safety.

An innovative double-jet design as an air flow barrier to isolate temperature and humidity in a low-temperature storage room

This study used an innovative double-jet design to isolate the temperature and humidity of a lower temperature storage room (-15 °C) from an adjoining higher temperature room (5 °C). This device can reduce the chance of forming a hazardous area in the working environment. Several axial fans are installed on the top of the flow isolation device (FID) to provide an air flow barrier. Those fans blow the air that can induce the Coanda effects outside of the FID. A blockage body is designed and installed in the downstream area on a perforated plate that can divide the flow into two symmetric separated jets. Computational Fluid Dynamics (CFD) is used to simulate the flow pattern with two different practical air velocities, 5 and 5.6 m/s. The results show that the case where the FID is installed in both rooms exhibits the highest isolation efficiency, up to approximately 94% for RH and 93% for temperature. The findings of flow analysis demonstrate that significant amounts of energy can potentially be saved. The practical implications of these findings could be in food and pharmaceuticals industries.

Real-time risk assessment of multi-parameter induced fall accidents at construction sites

In this research, a risk assessment model was developed that concurrently considers the location and physiological risk factors for fall accidents in workers at construction sites. In terms of location risk, data on 1683 occupational fall accidents involving 1718 worker casualties in the construction industry were collected for the period 1996–2016 from the Institute of Labor, Occupational Safety and Health (ILOSH), Taiwan. Next, the locations of these fall accidents were identified and defined as hazardous areas, with each area assigned a fall-risk level based on the average number of occupational accidents per year. In terms of physiological risk, the thermal hazard evaluation model, Recommended Alert Limits/Recommended Exposure Limits (RALs/RELs), developed by the National Institute for Occupational Safety and Health (NIOSH), USA was used in this study. This model uses metabolic heat and wet bulb globe temperature (WBGT) to recommend hourly rest/work times for workers. Using WBGT and one hour as the basic unit of time, varying degrees of metabolic heat, defined as metabolic heat loading severity (MHLS), were obtained. An optical heart rate (HR) sensor was applied in this study to measure HR, which was subsequently converted to a metabolic heat value using the Malchaire J metabolic heat evaluation model. Next, metabolic heat loading risk level was evaluated based on the MHLS. Finally, the location-based fall-risk level was multiplied by the MHLS, generating a risk evaluation model for fall accidents. The evaluation results identify the real-time fall-risk level of each worker and, if needed, suggest actions to be taken to mitigate the elevated risks of fall accidents identified by the model.

Research on intelligent search-and-secure technology in accelerator hazardous areas based on machine vision

Research on intelligent search-and-secure technology in accelerator hazardous areas based on machine vision

Study of the influence of different ignition times on detonation generation and shock wave propagation in high-pressure hydrogen leakage

Hydrogen is an efficient, clean, and renewable energy source. When determining a place for hydrogen energy storage and injection into vehicles, the main safety concern of hydrogen refueling stations is high-pressure hydrogen leakage. In this paper, the CFD method is used to study the effect of different ignition times on the explosion and shock wave propagation of high-pressure hydrogen gas leakage, analyze the distribution of flammable gas clouds, and evaluate the impact of combustion flames, temperature, and explosion-induced overpressure on refueling stations. The results show that the concentration of gas clouds ranges from 0 to 80% (volume concentration). Explosion and combustion phenomena occur at different ignition times during the high-pressure hydrogen gas leakage stage, with a maximum pressure of 2.6 bar and a high temperature of 1500–2400 K. After a high-pressure hydrogen leak, ignition can occur only as an explosive phenomenon. This generates a pressure of up to 3.1 bar and a short-lived high temperature. The pressure increases with the length of the leak, and the hazardous area varies depending on the time of ignition. This paper provides theoretical support for safety issues related to high-pressure hydrogen leakage in refueling stations.

IOT Based Accident Alert System

Abstract: Transportation has great importance in our daily life and it’s development has made many of our chores much easy. IoT based accident alert system aims to provide real-time warnings to drivers as they approach hazardous areas using ESP32 Ultrasonic Sensors and RF Transmitter and Receiver has gained attention. When a vehicle or a car comes near the accident prone area, ESP32 alongwith Speaker and Audio amplifier whichis situated in a car produces a beep sound through which the driverin the car getsan alarmsound that thereis an accident prone area nearby.

Operation of Track Sections in Avalanche Hazardous Areas by the Example of the Serebryansky Track

The fight against avalanches and the elimination of their consequences is urgent. The purpose of the article is to develop measures for preventing avalanches, especially sudden but not only planned ones. The subject of the study is snow avalanches, their volumes, and their causes. The result of the study is the development of standard technological flowcharts for snow removal work on the backbone network of the NC KTZh JSC. Freight trains travel 1000 km per day. It is necessary to increase this speed to 1200 km/day. The nominal FTI amounted to 75 trillion tenge in 2020; in 2024 it will be 106 trillion tenge. This will require transportation of construction materials and minerals, gasoline and diesel fuel, grain and flour, fertilizers, seeds, herbicides and pesticides, crop and livestock products.

Uncrewed aerial vehicle with onboard winch system for rapid, cost-effective, and safe oceanographic profiling in hazardous and inaccessible areas

Interactions between coastal waters and marine-terminating glaciers in the Polar Regions play a significant role in global sea level rise fueled by a rapidly warming Arctic.The risk of glacier calving, and the abundance of ice, can make it impossible for surface vessels to access the waters near glacier termini. Alternative methods using manned aircraft are expensive. As a result, oceanographic measurements are limited near glacier termini.We present an uncrewed aerial vehicle (UAV) with an on-board winch system that allows oceanographic profiling in remote, hazardous areas using a commercial conductivity, temperature, and depth (CTD) sensor payload. The UAV is optimized for easy handling and deployment and is capable of high-speed and efficient cruise flight. An autopilot system provides pilot assistance and autonomous flight capabilities. The total weight of the UAV including payload is 6.5 kg with an endurance of 24 min.Testing of the system was conducted in South Greenland during winter conditions in March 2023 with successful profiles collected near a glacier terminus (<5 m) and in small openings in ice mélange (2.2 m). The system proved capable, reliable, and efficient. Further development of the system will allow other sensors for an even more flexible measurement suite.

Health risk assessment of soil heavy metals in a typical mining town in north China based on Monte Carlo simulation coupled with Positive matrix factorization model

The accumulation of heavy metals (HMs) in soil caused by mineral resource exploitation and its ancillary industrial processes poses a threat to ecology and public health. Effective risk control measures require a quantification of the impacts and contributions to health risks from individual sources of soil HMs. Based on high-density sampling, soil contamination risk indexes, positive matrix factorization (PMF) model, Monte Carlo simulation and human health risk analysis model were applied to investigate the risk of HMs in a typical mining town in North China. The results showed that As was the most dominant soil pollutant factor, Cd and Hg were the most dominant soil ecological risk factors, and Cr and Ni were the most dominant health risk factors in the study area. Overall, both pollution and ecological risks were at low levels, while there were still some higher hazard areas located in the central and south-central part of the region. According to the probabilistic health risk assessment (HRA), children suffered greater health risks than adults, with 21.63% of non-carcinogenic risks and 53.24% of carcinogenic risks exceeding the prescribed thresholds (HI > 1 and TCR>1E-4). The PMF model identified five potential sources: fuel combustion (FC), processing of building materials with limestone as raw materials (PBML), industry source (IS), iron ore mining combined with garbage (IOG), and agriculture source (AS). PBML is the primary source of soil HM contamination, as well as the major anthropogenic source of carcinogenic risk for all populations. Agricultural inputs associated with As are the major source of non-carcinogenic risk. This study offers a good example of probabilistic HRA using specific sources, which can provide a valuable reference for strategy establishment of pollution remediation and risk prevention and control.

Coupled simulation-optimization model for pedestrian evacuation guidance planning

Effective evacuation guidance can guarantee people's safety by facilitating their swiftly exit hazardous areas during an emergency. However, pre-determined guidance plans based solely on distance comparisons to exits may not always be the most effective due to unstable accessibility conditions and uneven crowd distribution. Therefore, it is imperative to incorporate real-time optimal guidance information in the plan. Coupling simplified CTM (Cell Transmission Model)-based simulation, this study proposed a computationally efficient DRF (Directed Rooted Forest)-encoded planning for developing evacuation guidance plan. Taking them as a holistic model, the simulator predicts evacuation dynamics at a constant computational cost regardless of crowd size, while the planning module optimizes the guidance plan directionally by leveraging the simulation's intermediate and final outputs. Numerical tests have demonstrated that the tight coupling between optimization and simulation module has substantially enhanced the model's capacity to fine-tune the guidance plan and optimization efficiency. The proposed model may serve as the foundation for developing real-time evacuation guidance plans for large-scale crowded buildings, either on the premise of accelerated simulation or as an efficient generator of training data for machine learning models.

Theoretical Boundaries of Annual Flood Risk for Single-Family Homes Within the 100-Year Floodplain

Special flood hazard areas (SFHAs), defined as having an annual probability of occurrence of 1 percent or above, are used by U.S. Federal Emergency Management Agency (FEMA) to demarcate areas within which flood insurance purchase is required to secure a mortgage. However, quantifying flood risk within SFHAs can be challenging due to the lack of modeled flood depth data for all return periods. To address this issue, this research quantifies flood risk indicated by average annual loss (AAL) within the A Zone—the subset of the SFHA where wave heights can potentially range from 0 to 3 feet. The methodology resolves the Gumbel quantile function for four distinct flooding cases (i.e., locations flooded at return periods exceeding 1.58-, 10-, 25-, and 50-year return period events) and generates synthetic flood hazard parameters for these cases within the 100-year floodplain, as well as with additional elevation above the base flood elevation (BFE), known as freeboard, for single-family homes with different attributes. The results indicate that for single-family homes in the A Zone, with the lowest floor elevated to the BFE, the AAL ranges from 0.3 to 1 percent of the building replacement cost value. Adding one foot of freeboard reduces flood risk by over 90% if the annual flood risk is between the minimum and 25th percentiles and the 100-year flood depth is less than two feet. The demonstrated approach helps enhance flood resilience in the A Zone, demonstrating the feasibility of proactive measures to protect communities.

Методика прогнозирования зон скопления сероводорода в сильвинитовых пластах калийных рудников и экспресс-определения газоносности пород по сероводороду

Intensification of potash salt mining, widespread use of high-performance continuous miners, involvement of gasbearing formations in mining are accompanied by release of natural poisonous gases into the atmosphere of mine workings, which explains the need to ensure safe working conditions for the miners. The article presents the researche results that helped to develop a methodology for predicting accumulation zones of one of the most hazardous poisonous gases, i.e. hydrogen sulfide. A correlation was established between the hydrogen sulfide concentration, presence of organic substances and the content of magnesium chloride in the rocks. The article describes methods to determine the accumulation areas of hazardous sulfurcontaining gases based on the trench sampling and laboratory test data, which makes it possible to take timely protective measures to ensure safety of the miners. The developed method is based on creation of the correlation fields for various geochemical attributes such as the NaCl, KCl, MgCl2 content and others. A close correlation between the content of organic carbon in the rocks and magnesium chloride indicates the degree of salt recrystallization, as evidenced by an increase in the hydrogen sulfide content. In addition, the article describes an express method to determine the gas content in rocks, which enables a quick and accurate assessment of hydrogen sulfide concentration directly in the mine workings, thus providing the possibility of prompt response to the hazards. Thus, the methodology proposed by the authors serves not only to identify the potentially hazardous areas, but also to prevent dangerous situations associated with the release of poisonous gases in potash mines. The research and practical approaches described in the article as well as the developed recommendations contribute to enhancing the efficiency of mine ventilation, which in turn leads to minimization of the risks to health and life of the miners.

Seismic isolation technology of shallow buried large section utility tunnel with soft soils in seismically vulnerable area

Shallow utility tunnels with exceptionally large cross-sections in weak soil can face significantly more severe seismic risks compared to conventional deep tunnels in seismic hazard areas. This study investigates the seismic response and isolation technologies applied to a large section utility tunnel with 4 compartments in one layer, employing seismic simulations. The engineering context, dynamic motions, and measuring points of the numerical simulation were introduced. Subsequently, the finite element method was employed to explore the seismic behaviors of the large section utility tunnel when subjected to strong earthquake excitations under four conditions. The study explored and comparatively evaluated the seismic isolation effectiveness of three proposed schemes: the grouting scheme, the buffer layer, and the assembly of three-quarters buffer layer, cushion and grouting. The analysis included various indexes such as the deformation, the principal and shear stress, and the safety factor. The finding reveals that the assembly seismic scheme exhibits the most significant seismic effect (95.39%), followed by the buffer layer (38.82%), and the grouting scheme (25.66%). The assembly seismic scheme is recommended for the seismic design in the current large-section utility tunnels. These conclusions provide valuable scientific guidance for the seismic design of large-section utility tunnels, aiding in enhancing earthquake resilience.

Geochemical baseline establishment, pollution level and health risk assessment of soil heavy metals in the upper Xiaowen River Basin, Shandong Province, China.

This study analyzed the distribution and content of eight heavy metals (Cu, Pb, Zn, Ni, Cr, As, Cd, and Hg) in 221 surface soil samples from the upper reaches of the Xiaowen River. Environmental geochemical baselines were established for the eight heavy metals, and the pollution status was assessed on the basis of these baselines and the soil background value of Weifang City. The calculation results of Nemerow pollution index and the potential ecological hazard index (PEHI)-Ri showed that the overall pollution degree and ecological hazard in the study area were at a slight level. 49% (calculated by baseline value) and 24% (calculated by background value of Weifang City) samples were at moderate or above pollution level. 9% (calculated by baseline value) and 42% (calculated by background value) samples were at the level of moderate potential ecological hazards or above. According to the calculation results of Igeo and PEHI-Ei, the main pollutant in the study area was Hg, followed by Cd. 3% (calculated by baseline value) and 12% (calculated by background value) of Hg samples were at moderate or above contamination levels. 5% (calculated by baseline value) and 38% (calculated by background value) of Hg samples were at the level of strong potential ecological hazard or above. The western, central, and eastern parts of the study area were mainly the primary areas of pollution and ecological hazards. The non-carcinogenic risk was at an acceptable level, the carcinogenic risk was at a tolerable level, and the main risk pathway was oral intake, with Cr being the main contributor. Source apportionment indicated that soil heavy metals primarily originate from soil parent material, transportation, agricultural fertilization, and industrial emissions (waste gas, waste water and solid waste).

Testing the predictive ability of a karst subsidence susceptibility map made thirty years ago in the central Ebro Basin (Zaragoza, Spain)

Karst subsidence has caused damage in numerous buildings and infrastructures in the surroundings of Zaragoza city since the early 1970s, when rapid urbanization of the area begun. A detailed survey carried out in 1991 allowed recognizing and mapping damages in an industrial district, and elaborating a susceptibility or spatial hazard map based on (i) the observed presence of active alluvial dolines, and (ii) spatial distribution of factors controlling their development, according to a hazard model based on both spatial analysis and laboratory experimental simulation. The predictive ability of such spatial hazard map is now tested, thirty years later, by a new detailed field survey carried out in 2021 covering almost the same area. The results allow mapping of the total present-day damage and, using GIS tools, also a residual map of areas newly damaged since 1991. After comparing those maps with the hazard zonation proposed in 1991, we conclude that: (i) the predictive ability of the latter is good in overall; (ii) the areas of highest subsidence hazard have a probability in the range of 19–38% of suffering damage over a 30-year period, while this probability systematically decreases up to about 7% for the lowest hazard areas; (iii) the average rate of occurrence of new damage within the overall study zone has remained quite uniform around 0.5% in area per year. Incorporating such calculations of temporal probability of occurrence associated to each hazard category allows the original susceptibility map to approach a hazard s.s. map, providing annual probabilities of occurrence between ~ 0.6 to 1.3% and ~ 0.3% for the distinct hazard zones.

Integrating BIM and computer vision for preventing Hazards at construction sites

Construction safety monitoring is vital in enhancing site safety, such as tracking entering hazardous areas and the correlation between workers and other hazard entities. Therein, computer vision-based image/video processing, one of the emerging technologies, has been actively used to automatically identify and recognize unsafe conditions. However, the construction site has various potential hazard situations during the project. Due to the site’s complexity, many visual devices simultaneously participate in monitoring. It challenges developing and operating corresponding detection algorithms at specific workplaces and times. Besides, safety information detected by computer vision must be organized before being delivered to stakeholders. Hence, this study proposes an approach for construction safety monitoring using vision intelligence technology and BIM-cloud, called BMT. The BMT comprises two modules: (1) the virtual model based on the 4D BIM-cloud model, which provides the spatial-temporal information to decide computer vision algorithm adoptions; (2) the construction physical model built the vision intelligence technologies, which is supported by (1) and deliver safety status and update into the BIM-cloud model to visualize and deliver the risk level to related employees. The efficiency of the BMT approach is validated by testing with the preliminary implementation of a prototype.