Gas explosion characteristics and spray control mechanism in underground square.

The spray system mechanism during a gas explosion in an underground square pipeline is complex. In this paper, the underground square of Fuxin City is selected as the research object. FLACS numerical simulation software is used to analyze the spatial and temporal distribution characteristics of a gas explosion in an underground square pipeline with an unopened spray system using combustion and combustion rate models. Different spray pressures were compared and analyzed to determine the optimal spray control pressure, and the spray system mechanism was clarified. The results revealed that the gas explosion overpressure is divided into the overpressure gentle, overpressure rising, and overpressure decay stages, corresponding to a trend of rapid growth and slow decline. The influence of spray pressure on the gas explosion exhibits a promotion-inhibition-promotion trend, corresponding to 0-0.2 MPa, 0.2-0.6 MPa, and 0.6-1.6 Mpa, respectively. The peak overpressure and overpressure propagation rates are the lowest at 0.6 MPa, and the explosion suppression effect is the most pronounced. The spray system mechanism varies with the explosion overpressure stages. Generally, the time to peak value, that is, the peak time, the overall duration of the explosion, and the duration of the explosion stage decrease, whereas the peak explosion overpressure decreases.

Fuzzy multi-criteria decision-making framework for controlling methane explosions in coal mines.

The structure of underground coal mines is vulnerable to many mishaps because of the challenging conditions of production and the unique features of the earth. These incidents could cause significant financial and production losses for the mines in addition to worker injury, disability, or death. In coal mines, methane explosions are a frequent threat. Establishing a safe work environment requires managing these problems with an accident control method. The current study used the fuzzy TOPSIS and fuzzy AHP techniques for this aim. The framework was used to tackle the four-alternative problem of underground coal mine explosion control method selection. To identify potential risks of a methane explosion, a data gathering survey was conducted as part of the suggested hybrid methodology. The fuzzy AHP was used to compute the fuzzy weights of the hazards. "Improper ventilation system" is ranked highest out of the 34 sub-risk factors. The fuzzy TOPSIS was then utilized to rank the explosion control methods using the weights. To assess the viability of the study's conclusions, a sensitivity analysis was carried out. The findings indicate that "improving safety technology" and "financial investments" are the best ways to reduce such events. The results additionally indicate that the fuzzy TOPSIS approach in combination with the fuzzy AHP provides a helpful framework for dynamically assessing mine methane explosion accidents.

FRAM-based causal analysis and barrier measures to mitigate dust explosions: A case study.

Both the number of dust explosion accidents and the resulting number of casualties have increased dramatically in recent years. To reduce this risk of dust explosions, we use the functional resonance analysis method (FRAM) to analyze the cause of the dust explosion accident at the Kunshan factory and propose barrier measures to prevent such accidents. The functional units that changed in the production system during the accident and how these functional units coupled to eventually cause the dust explosion were examined and explained. In addition, barrier measures were developed for functional units that changed during production and emergency systems defined to block the propagation of changes between functions and prevent resonance. Through case study, the identification of key functional parameters in both triggering the initial explosion and in then allowing its spread are key to define barriers to prevent a recurrence of such an event. FRAM uses system function coupling instead of traditional linear causality to explain the accident process, and develops barrier measures for changing function units, providing a novel thinking strategy and method for the analysis of accidents and their prevention.

Combustible wood dust explosions and impacts on environments and health - A review.

Wood dust is the major wastes from timber and wood-based panel processing, including wood sawing, sanding, chipping, flaking, etc., which easily causes fire and explosions. The fine wood dust had risks of inhaling the dust air, causing problems to the respiratory system of workers, as well as the explosive risk of the wood dust-air mixture. Wood dust explosions occur worldwide, which have caused massive damages to equipment, buildings, and environments, killed people, and threatened human health. This study was aimed at exploring the causes, affecting factors, mechanisms, models of wood dust explosions, and their environmental/health impacts through reviewing and analyzing the collected data in order to minimize wood dust explosion risks by improving of safety procedures in the wood processing industry. To better understood and prevent wood dust explosion cases in the future, this review collected the explosion reports and analyzed the accident information through the following aspects: 1) Summarization of published review articles regarding wood dust explosions in Introduction, 2) Scrutinization of wood dust explosion cases and design of testing device, 3) Exploration of effects of wood dust properties and surrounding conditions on explosion and their mechanisms, 4) Investigation of methods for reducing wood dust explosion risks, 5) Modeling and simulation of wood dust explosions, 6) Examination of environmental and health impacts of wood dust explosions. Finally, the findings in this review were summarized in Conclusions. By collecting dust explosion reports, reviewing literature, and analyzing the collected data, wood dust explosions can be better understood. The results of this study can be useful for the design of equipment and dust absorption systems, as well as further suggestion of safety improvement procedures to minimize or eliminate risks of wood dust-related fire and explosion in the wood processing industry and mitigate its impacts on environments and health.

Encouraging Firework Safety Through Public Service Announcements.

A dramatic increase in firework-related blast injuries to the hand and upper extremity resulted in record-setting numbers at our institution over the July 4, 2018, holiday. This led our hand and upper extremity department to create a public service announcement (PSA) campaign regarding firework safety and injury prevention. This PSA was broadcast in advance of the next July 4 holiday via several media platforms including television, radio, and the internet. The following year only 4 patients required surgery for firework-related blast injuries to the hand and upper extremity over the same 10-day period, including the weekends before and after the July 4, 2019, holiday. This represented a considerable reduction compared with the 14 patients seen within the same time frame in 2018. The purpose of this article was to outline the process and report the impact of creating and disseminating a public service announcement for firework-related blast injury prevention.

Rehabilitación de trauma facial ocasionado por fuegos artificiales utilizando triamcinolona / Aesthetic and functional rehabilitation using triamcinolone on patient suffered by facial firework injury

Introduction: Facial injuries are a common occurrence at the emergency room. Treatment for this type of trauma is complex in terms of re-establishing good oral and facial function, plus aesthetics. Objective: This paper aims to report a clinical case of aesthetic and functional rehabilitation using triamcinolone in a patient affected on the face by a fireworks explosion. Case report: A 26-year-old man was admitted to the oral and maxillofacial surgery service of the Sergipe Urgency Hospital presenting trauma after the explosion of a "Firework rocket" in his face. The patient had extensive soft tissue injury in gingival mucosa, right labial commissure, and tongue. There was also inferior incisive avulsion and dentoalveolar fracture. His clinical and tomographic evaluation presented comminuted mandibular fracture. After eighteen days he was discharged and sent to the dentistry service of the Federal University of Sergipe for aesthetic and functional rehabilitation of his facial damages. Two months later, the patient attended a University dental service to begin aesthetic and postoperative functional rehabilitation. First, the necrotic bone was removed, following intralesional infiltration of hexacetonide triamcinolone 20mg/mL into the scar of the labial region and the commissure of the lips was performed. Each application was performed after twenty days of interval. Later, lingual frenectomy and glossosplasty were done for improving his lingual mobility and then hexacetonide triamcinolone 20mg/mL infiltrations were also done in the tongue base in the following sessions. Conclusions: After five infiltrations, it was observed an improvement in the scar appearance and texture, which also had a lower contracture, as well as a lingual motricity improvement(AU)

Introducción: Las lesiones faciales son frecuentes en el servicio de emergencia. El tratamiento para este tipo de trauma es complejo en términos de restablecer una buena función bucal y facial, además de la estética. Objetivo: Reportar un caso clínico de rehabilitación estética y funcional a través del uso de hexacetónido de triamcinolona en un paciente afectado por una explosión de fuegos artificiales en su rostro. Caso clínico: Hombre de 26 años ingresado en el servicio de cirugía oral y maxilofacial del Hospital de Urgencia de Sergipe por presentar un traumatismo después de la explosión contra su rostro de un cohete de fuegos artificiales. El paciente tenía una lesión extensa de partes blandas en la mucosa gingival, comisura labial derecha y lengua. También hubo avulsión incisiva inferior y fractura dentoalveolar. A través de la evaluación clínica y de tomografía, fue posible observar fragmentación múltiple ósea en el sitio de la fractura, compatible con fractura mandibular conminuta. Después de dieciocho días fue dado de alta y enviado al servicio de odontología de la Universidad Federal de Sergipe para la rehabilitación estética y funcional de sus daños faciales. Dos meses después, el paciente asistió al servicio dental de la universidad para comenzar la rehabilitación funcional estética y posoperatoria. Primero, se retiró el hueso necrótico, luego se realizó la infiltración intralesional de hexacetónido de triamcinolona 20 mg/mL en la cicatriz de la región labial y se realizó la comisura de los labios; con un intervalo de 20 días entre cada aplicación. Posteriormente, se realizaron frenectomía lingual y glososplastia, para mejorar su movilidad lingual, y luego se realizaron infiltraciones de 20 mg/mL de hexacetónido de triamcinolona en la base de la lengua en las sesiones siguientes. Comentarios principales: Después de cinco infiltraciones se observó una mejora en el aspecto y la textura de la cicatriz, que también tenía una contractura más baja, así como una mejora de la motricidad lingual(AU)

A narrative review of hydrogen-oxygen mixture for medical purpose and the inhaler thereof.

Recent development regarding mixture of H2 (concentration of ~66%) with O2 (concentration of ~34%) for medical purpose, such as treatment of coronavirus disease-19 (COVID-19) patients, is introduced. Furthermore, the design principles of a hydrogen inhaler which generates mixture of hydrogen (~66%) with oxygen (~34%) for medical purpose are proposed. With the installation of the liquid blocking module and flame arresters, the air pathway of the hydrogen inhaler is divided by multiple isolation zones to prevent any unexpected explosion propagating from one zone to the other. An integrated filtering/cycling module is utilized to purify the impurity, and cool down the temperature of the electrolytic module to reduce the risk of the explosion. Moreover, a nebulizer is provided to selectively atomize the water into vapor which is then mixed with the filtered hydrogen-oxygen mix gas, such that the static electricity of a substance hardly occurs to reduce the risk of the explosion. Furthermore, hydrogen concentration detector is installed to reduce the risk of hydrogen leakage. Result shows that the hydrogen inhaler implementing the aforesaid design rules could effectively inhibit the explosion, even ignition at the outset of the hydrogen inhaler which outputs hydrogen-oxygen gas (approximately 66% hydrogen: 34% oxygen).

Crater detection from commercial satellite imagery to estimate unexploded ordnance in Cambodian agricultural land.

Unexploded ordnance (UXO) pose a significant threat to post-conflict communities, and current efforts to locate bombs rely on time-intensive and dangerous in-person enumeration. Very high resolution (VHR) sub-meter satellite images may offer a low-cost and high-efficiency approach to automatically detect craters and estimate UXO density. Machine-learning methods from the meteor crater literature are ill-suited to find bomb craters, which are smaller than meteor craters and have high appearance variation, particularly in spectral reflectance and shape, due to the complex terrain environment. A two-stage learning-based framework is created to address these challenges. First, a simple and loose statistical classifier based on histogram of oriented gradient (HOG) and spectral information is used for a first pass of crater recognition. In a second stage, a patch-dependent novel spatial feature is developed through dynamic mean-shift segmentation and SIFT descriptors. We apply the model to a multispectral WorldView-2 image of a Cambodian village, which was heavily bombed during the Vietnam War. The proposed method increased true bomb crater detection by over 160 percent. Comparative analysis demonstrates that our method significantly outperforms typical object-recognition algorithms and can be used for wide-area bomb crater detection. Our model, combined with declassified records and demining reports, suggests that 44 to 50 percent of the bombs in the vicinity of this particular Cambodian village may remain unexploded.

Application of fuzzy fault tree analysis based on modified fuzzy AHP and fuzzy TOPSIS for fire and explosion in the process industry.

This study aimed at establishing fault tree analysis (FTA) using expert opinion to compute the probability of an event. To find the probability of the top event (TE), all probabilities of the basic events (BEs) should be available when the FTA is drawn. In this case, employing expert judgment can be used as an alternative to failure data in an awkward situation. The fuzzy analytical hierarchy process as a standard technique is used to give a specific weight to each expert, and fuzzy set theory is engaged for aggregating expert opinion. In this regard, the probability of BEs will be computed and, consequently, the probability of the TE obtained using Boolean algebra. Additionally, to reduce the probability of the TE in terms of three parameters (safety consequences, cost and benefit), the importance measurement technique and modified TOPSIS was employed. The effectiveness of the proposed approach is demonstrated with a real-life case study.

Preventing explosions of hydrogen gas inhalers.

Production and excretion of hydrogen (H2) gas in human was reported in 1969, since then it has been regarded as non-toxic molecule. For preventive and therapeutic medical uses, a possible treatment for cancer was reported and another article was published on how H2 acts as a therapeutic antioxidant by selectively reducing cytotoxic oxygen radicals. A variety of H2 gas inhalers have been available in the market for hospital and home uses. However, H2 is odorless and flammable or explosive ignited by static electricity. We have examined the safety of a variety of H2 gas concentrations from the viewpoint of flammability and explosion. We have also measured concentrations of H2 gas inhalers in the market respectively. This paper also details how to control H2 gas concentration for preventing explosions.

Flammable Substances in Korea Considering the Domino Effect: Assessment of Safety Distance.

Benzene, toluene, and xylene (BTX) are flammable substances used in a wide range of raw materials and products. Chemical accidents caused by flammable substances are different from leakage accidents of toxic materials. Initial explosions and fires may cause secondary or tertiary explosions, or fires with nearby flammable materials. This is called the domino effect. In cases of leakage accidents, it is possible to prevent accidents through early control of the leakage to the outside or by bypassing, but it is difficult to cope with explosions because they occur instantaneously. To prevent explosions due to the domino effect, a safety distance must be set. Safety distances vary widely by country. In the case of the United States (US) or the European Union (EU), safety distances are set in various ways depending on the chemical industry and the amount of flammable substances being handled. However, countries such as Korea, Taiwan, and Dubai have comprehensive regulation, and the safety distances are small. In this study, we simulated the range of overpressure at which other chemical equipment could explode when an explosion occurs in a flammable BTX storage tank. There are three types of analysis methods of vapor cloud explosion. PHAST (Process Hazard Analysis Software Tool) and ALOHA (Areal Location of Hazardous Atmosphere) were selected to model explosions using three methods (trinitrotoluene equivalence method, the Netherlands Organization multi-energy method, and Baker-Strehlow-Tang method). The results indicated that the safety distances in the US and EU showed low probability of a domino effect, but those in Korea, Dubai, and Taiwan could lead to a secondary explosions. Therefore, it is necessary to propose a reasonable method to determine safety distances considering the amount and physicochemical characteristics of the flammable substances being used.

A systematic review of oil tanker truck disasters: Identifying prevention targets.

INTRODUCTION: Oil tanker truck disasters have been reported worldwide; however, the circumstances, causes, and health effects of these disasters have not been described. To address this gap, we performed a systematic review using PRISMA criteria to better understand this public health problem and identify prevention targets. METHODS: The academic and lay literatures were systematically searched for terms related to oil tanker truck disasters. Reports about civilian oil tanker truck disasters that occurred from 1997-2017 were included. Details about the disasters were summarized, including circumstances, identifiable causes, and health effects. RESULTS: The search yielded 4713 Nexis Uni articles, 199 Google results, and one PubMed article; 951 records met inclusion criteria, describing 224 oil tanker truck explosions or fires. At least 2909 people died as a result of these disasters, and 3038 additional people were hospitalized. Almost all deaths (94%) occurred in low- and low-middle-income countries (LMIC). This may largely be due to scooping - the practice of collecting spilled oil from disabled tanker trucks for use or resale. Using the Haddon matrix, potential targets for future disaster prevention were identified. CONCLUSIONS: These data highlight the circumstances, causes, and health burden related to oil tanker truck disasters. Most began as collisions or rollovers, but nearly half of the fatalities involved scooping. The findings suggest opportunities to promote road safety, improve scene safety and security protocols used by drivers and first responders, and promote public understanding of the dangers of scooping to prevent mass casualty disasters from disabled tanker trucks, particularly in LMIC.

Comparison of the CAS-POL and IOM samplers for determining the knockdown efficiencies of water sprays on float coal dust.

Float coal dust, generated by mining operations, is distributed throughout mine airways by ventilating air designed to purge gases and respirable dust. Float coal dust poses an explosion hazard in the event of a methane ignition. Current regulation requires the application of inert rock dust in areas subjected to float coal dust in order to mitigate the hazard. An alternate method using water sprays, which have been effective in controlling respirable dust hazards, has been proposed as a way to control float coal dust generated on longwall faces. However, the knockdown efficiency of the proposed water sprays on float coal dust needs to be verified. This study used gravimetric isokinetic Institute of Occupational Medicine (IOM) samplers alongside a real-time aerosol monitor (Cloud Aerosol Spectrometer with polarization; CAS-POL) to study the effects of spray type, operating pressure, and spray orientation on knockdown efficiencies for seven different water sprays. Because the CAS-POL has not been used to study mining dust, the CAS-POL measurements were validated with respect to the IOM samplers. This study found that the CAS-POL was able to resolve the same trends measured by the IOM samplers, while providing additional knockdown information for specific particle size ranges and locations in the test area. In addition, the CAS-POL data was not prone to the same process errors, which may occur due to the handling of the IOM filter media, and was able to provide a faster analysis of the data after testing. This study also determined that pressure was the leading design criteria influencing spray knockdown efficiency, with spray type also having some effect and orientation having little to no effect. The results of this study will be used to design future full-scale float coal dust capture tests involving multiple sprays, which will be evaluated using the CAS-POL.

Is There a Threat Towards Medical Institutions, and What to Do?

Unfortunately the reality of today is that a terrorist threat in Europe has become evident. With increasing frequency we are confronted with attacks all across Europe, at least this is the perception. So is there a Threat? If look at the paper of Wolf et al (1), this describes an increase of terrorist attacks from 1999- 2006, the amount of victims due to these attacks increased exponentially. This means the attacks are getting more effective. The perpetrators are getting better and are learning how to injure or kill more victims. The techniques are getting more sophisticated. For example if we look at the Bali Bombing in 2002, here a second hit technique is used. The terrorist placed first a small bomb in a tourist area, knowing that this eventually will attract many people who rush in to help the victims. Then a second hit was done with a much larger bomb killing and wounding even a larger group of people. This is the goal of the terrorist, introducing terror, shocking the world, introduce fear. If we look at the attack in Nice, South France. They used a truck driving through a large tourist crowd, knowing that there would be many children and young people. This is their ultimate goal, shock the world. With that mindset, just imagine how shocking would it be to primary attack a medical institution. Our weakness as medical people is that we want to help people, In fact we gave a Hippocratic oath that we will always help other people, that is our job. We find it hard to believe that medical relief institutions will be attacked. If we look at the London bombing in 2005, one of the terrorists detonated the bomb in a bus. By coincidence this happened right in front of the British Medical Association with many doctors in the building at that time. All of them immediately went to the exploded bus to provide medical relieve, did they even think for a second that there maybe would be a second hit? We are to nice, and the terrorists know this. Historyhas proven to us that medical institutions are a potential goal. 2008 a terror attack in Mumbai, eight series of attacks were done between 26-29th of November. Eventually the terrorist where heading for the CAMA hospital. However because the hospital was alerted and were able to perform a complete lock down they were able to prevent additional casualties in the hospital itself. Are these rare incidents?

A novel method of fuzzy fault tree analysis combined with VB program to identify and assess the risk of coal dust explosions.

Coal dust explosions (CDE) are one of the main threats to the occupational safety of coal miners. Aiming to identify and assess the risk of CDE, this paper proposes a novel method of fuzzy fault tree analysis combined with the Visual Basic (VB) program. In this methodology, various potential causes of the CDE are identified and a CDE fault tree is constructed. To overcome drawbacks from the lack of exact probability data for the basic events, fuzzy set theory is employed and the probability data of each basic event is treated as intuitionistic trapezoidal fuzzy numbers. In addition, a new approach for calculating the weighting of each expert is also introduced in this paper to reduce the error during the expert elicitation process. Specifically, an in-depth quantitative analysis of the fuzzy fault tree, such as the importance measure of the basic events and the cut sets, and the CDE occurrence probability is given to assess the explosion risk and acquire more details of the CDE. The VB program is applied to simplify the analysis process. A case study and analysis is provided to illustrate the effectiveness of this proposed method, and some suggestions are given to take preventive measures in advance and avoid CDE accidents.

Vermeidung von Feuer/Brand/Explosion im OP.

The combination of an oxidant source, ignition energy and flammable material is the reason for fire, burning and explosion (FBE) in the OR. Attending anaesthesiologists face these risks in their daily routine. Mostly, a situation with FBE arises in an unexpected situation. It is essential to have at hand a catalogue of measures to prevent severe injuries to patients and avoid material damages. There is a systematic way to decrease the risk: awareness and definition of high-risk situations; team work; building up a strategy to avoid the occurrence of fire, burning and explosion in high-risk situations. The risk profile should be part of security checklists. If there is physical injury caused by fire in the OR, the extent of trauma must be assessed and documented. Finally, an interdisciplinary review may be indicated. Institutional standards regarding risk- and quality management, e. g. working place orders and measures of fire prevention, increase patient security. Systematic implementation of measures and annual training sessions are indispensable.

Cremation of Leadless Pacemaker.

Cremation of implanted cardiac electronic devices can be associated with explosion from rapid gas formation causing potential hazard to the crematoria staffs and facilities. We present four patients who had undergone cremation with a leadless pacemaker (MicraTM , Medtronic Inc., Minneapolis, MN, USA) left inside their bodies. There was neither reported explosion nor damage to the cremation chamber during the cremation process. In this small series, cremation of MicraTM is not associated with noticeable explosion.

Comparison of coarse coal dust sampling techniques in a laboratory-simulated longwall section.

Airborne coal dust generated during mining can deposit and accumulate on mine surfaces, presenting a dust explosion hazard. When assessing dust hazard mitigation strategies for airborne dust reduction, sampling is done in high-velocity ventilation air, which is used to purge the mining face and gallery tunnel. In this environment, the sampler inlet velocity should be matched to the air stream velocity (isokinetic sampling) to prevent oversampling of coarse dust at low sampler-to-air velocity ratios. Low velocity ratios are often encountered when using low flow rate, personal sampling pumps commonly used in underground mines. In this study, with a goal of employing mine-ready equipment, a personal sampler was adapted for area sampling of coarse coal dust in high-velocity ventilation air. This was done by adapting an isokinetic nozzle to the inlet of an Institute of Occupational Medicine (Edinburgh, Scotland) sampling cassette (IOM). Collected dust masses were compared for the modified IOM isokinetic sampler (IOM-MOD), the IOM without the isokinetic nozzle, and a conventional dust sampling cassette without the cyclone on the inlet. All samplers were operated at a flow rate typical of personal sampling pumps: 2 L/min. To ensure differences between collected masses that could be attributed to sampler design and were not influenced by artifacts from dust concentration gradients, relatively uniform and repeatable dust concentrations were demonstrated in the sampling zone of the National Institute for Occupational Safety and Health experimental mine gallery. Consistent with isokinetic theory, greater differences between isokinetic and non-isokinetic sampled masses were found for larger dust volume-size distributions and higher ventilation air velocities. Since isokinetic sampling is conventionally used to determine total dust concentration, and isokinetic sampling made a difference in collected masses, the results suggest when sampling for coarse coal dust the IOM-MOD may improve airborne coarse dust assessments over "off-the-shelf" sampling cassettes.