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An adverse effect resulting from explosive mine blasts is the production of toxic nitrogen oxides (NO and NO2) and carbon monoxide (CO). The empirical measurements of the concentration of toxic gases showed that it depends not only on the composition of an explosive and properties of its ingredients but also on several other parameters, such as volume of blasting chamber, explosive charge mass and design, confinement characteristics, surrounding atmosphere, etc. That explains why measured concentrations of toxic gases reported in literature significantly differ. In this paper, we discuss the possibility of theoretical prediction of the concentration of toxic gases by thermochemical equilibrium calculation applying two models: ideal detonation model and deflagration model. It can be demonstrated that thermochemical calculations can provide a good estimation of the measured concentrations and reproduce experimentally obtained effects of additives on the production of toxic gases. It was also found that the ideal detonation model applies to heavily confined explosive charges, while the deflagration model is more suitable for low detonation velocity explosives with light confinement.

Background: Victims of flame burns invariably inhale smoke which contains potentially toxic gases that may contribute to their morbidity and mortality. The most significant inhalational toxin in many fires is carbon monoxide (CO). This study aimed to assess clinical evidence for possible CO poisoning and measure Carboxyhemoglobin (COHb) levels on fire casualties presenting to a tertiary teaching and referral hospital in Kenya. The gold standard, serum COHb spectrophotometry was unavailable hence pulse CO-oximetry was utilised to measure carboxyhemoglobin saturation (SpCO). Methodology: This was a prospective descriptive study. It was approved by institutional ethics committee. Eighty non-pediatric patients presenting with acute (10% indicating CO toxicity. However, the majority recorded nontoxic levels of

Ventilation is an available measure to dilute the released toxic gas and has been widely applied in offshore facilities to mitigate the adverse impact. However, “available” is never the same as “effective”. Up to now, the mitigation performance of ventilation remains a challenging topic that needs to be further studied. To identify the effectiveness of the mitigation, a systematic approach is proposed concerning the toxic impact caused by the diluted toxic gas, during which the emergency evacuation is considered. The grid-based concept is adopted to identify the initial position with the worst toxic impact. Then the effectiveness of ventilation is estimated according to its ability on mitigating the worst toxic impact. Taking an offshore platform as a case, the toxic impact under different H2S leakage scenarios are predicted. The dependencies among the wind speed, leakage rate, concentration of H2S, and toxic impact are discussed. Some safety-related results can be obtained, such as accident scenarios where ventilation can effectively mitigate the toxic impact. The present work could provide guidance to improve the safety of design and emergence plans in H2S release accidents.

The amount of toxic benzene gas is increasing rapidly due to development in plastic industries and also due to more amount of vehicle exhaust & gasoline production all over the world. These results not only develop the wealth of a nation, but it seriously affects the environment, human and other living beings. Through this project. We can detect high toxic benzene gas in the car cabin and industry on working condition. By this detection of benzene gas, exposure of passengers to such toxic gases inside vehicle cabin is considerably decreased. In this work, focus has been on car’s interior toxic gas detection due to which deformation taken place on dashboards, seats and other plastics on hot weather condition. By this it is also necessary to indicate the value of gas concentration in car’s interior in ppm reading. Thereby, a battery is fixed inside a car, and a GSM module and Arduino is powered. MQ135 gas sensor detects the benzene level inside of the car and it will be projected on an LCD display. When the benzene level is increased above 300 ppm, a message will be sent to the mobile as “GAS LEVEL HIGH” and we command a text through mobile as “*START#”, by this the exhaust fans and car blower starts, where the car blower blows air from environment to car interior cabin and the exhaust fans expels out the car’s interior benzene gas to the environment. When the ppm level is decreased to normal level which is below 286 ± 14 ppm, a message would be received through mobile phone as “GAS LEVEL LOW” and we command a text as “*STOP#”, thus within 7 min the ppm level decreases from 300 to 286 ± 14 ppm. By this, the exhaust fans and car blower stops. Hence higher level of safety is ensured from the toxic gas produced inside a car cabin and instead of manually opening the door glass to reduce the benzene level.

Cementitious concrete experiences remarkable sensible difficulty in achieve high compressive quality and quality of unrivaled structures. Presently the current assessment oversees finding the other alternative material for restricting the issues achieved by fine aggregate and binding material. Present days the nature of normal sand is corrupting and delving at higher profundity in streams prompts land sliding etc. The air is being contaminated because of the destructive gases and poisonous results that are delivered during the creation of concrete. In this unique situation, we are working with the substitution of Conventional sand by make sand creating from squashing of bigger rocks into fine particles of required size fit as a fiddle in different rates such as 20%, 40%,60%,80% and 100%. for M20 grade concrete. To minimize the effect of Toxic gases on Appearance of the Structure adding Titanium Dioxide (TiO2) in various percentages such as 2%,4%,6%,8% and 10% instead of Cement. To minimize the usage of cement content use Palm oil Fuel Ash (POFA) as binding material instead of cement for various proportions such as 4%,8%,12%,16% and20%. The Work-ability, Strength limits at various degrees of substitute materials Titanium Dioxide (TiO2), Manufactured Sand and POFA are attempted at different stages and find the certain improvement in major characteristics of conventional concrete.

Improving the performance of IC engine and reducing the toxic gases by applying the advance technology is the main key to safeguard the nation economy and health. The current study evaluates the emission of the single cylinder four-stroke diesel engine by adding proper additives ferric chloride (FeCl3) and diethyl ether (DEE) with diesel at various engine loads. The investigation defeats that CO emission is decreased by 62% using diesel + DEE15 blend compared to diesel fuel, whereas it is noticed to be reduce by 14% using diesel + FeCl3 blend of fuel. CO2 emission is found to be higher by 8% using diesel + FeCl3 as fuel compared to diesel which is further decreased by 5% using diesel + DEE15 compared to diesel + FeCl3. HC emission is found to be decreased by 38% and 42% respectively by using diesel + FeCl3 and diesel + DEE15 compared to diesel as fuel. NO emission is found to be increase by 35% using diesel + DEE15 compared to diesel fuel which is accounted to be 17.82% higher compared to diesel + FeCl3 at full load condition. Smoke opacity is found to be reduced by 72% using diesel + DEE15 compared to diesel + FeCl3 as fuel.

The environmental pollution has become a major concern of today’s era. Toxic gases such as CO, CO2 and NO2 are emitted from vehicles, industries, burning of crops etc. These gases are contributing a lot to the air pollution and also producing long term effect on lungs and respiratory system of human beings. Therefore gas sensing measurements for such toxic gases has received major attention. In this study, CuO is deposited by simple spray pyrolysis method and used for gas sensing measurements. The concentration of precursor solution is varied as 0.05 M, 0.1 M, 0.15 M and 0.2 M. The structural and morphological studies are done using XRD patterns and SEM images respectively. XRD patterns reveal the cubic structure of CuO. Gas sensing measurements have shown that the film deposited for 0.15 M concentration shows highest response of 56.23% for NO2 gas. The lowest detection level has observed to be 5 ppm of NO2. CuO has been found to be selective towards NO2 gas.

Levulinic acid can be produced through various routes; synthesis, bio, and extraction routes. These routes release toxic gases and waste materials during the levulinic acid production. Therefore, it needs an environment-friendly method for the manufacture of levulinic acid. In synthesis route, various substrates viz. xylose, maltose, and sucrose translate to levulinic acid. Also, the bio route uses H2SO4, HCl for pre-treatment in the fermentation process during the production of levulinic acid and generates toxic wastes. In the present paper, an attempt is made to discuss the opportunities and challenges for the production of levulinic acid by synthesis, bio, and extraction routes.

Power generation is associated with toxic emissions. Hydrogen sulfide (H2S) and ammonia (NH3) are toxic gases emitted from geothermal power generation that have negative impacts on health and the environment. Oxidation of H2S leads to formation of SO2 that also has health and environmental effects. The Cerro Prieto geothermal power plant (CP-GPP) is one of the largest in the world and is located 30 km south of Mexicali, a border city between Mexico and the US. Power from this plant is sold to both countries. In order to assess the potential effects of the emissions from the GPP on nearby low-income communities, H2S, SO2 and NH3 concentrations were measured at Nuevo Leon, El Chimi, and Estacion Delta, using passive samplers from November 2013 to June 2014. The highest concentrations of H2S were recorded during periods of high atmospheric stability, and exceeded the limit recommended by the WHO (150 μg m−3, 24-h) three times downwind from the GPP. Similarly, the mean SO2 concentrations at all three sites exceeded the limit established by the NOM-022-SSA1-2010 (288 μg m−3, 24-h), while NH3 concentrations exceeded the limits established by the OEHHA (100 μg m−3, 24-h) eight times at Nuevo Leon. A backward trajectory analysis indicated transport of air masses from the GPP to El Chimi and Estacion Delta sampling sites. The results indicate that GPP's emissions could affect the residents in the surrounding areas, warranting public health action to investigate exposures and risks.

Risk management of hydrogen sulphide is a challenging task in refinery operations. Despite the availability of very accurate modelling techniques and the compliance with internationally shared risk limits in hydrogen sulphide release prevention, post-release mitigation of hydrogen sulphide often remains a critical scenario. Fluid curtains are a well-known technology, which has successfully been adopted to mitigate mainly releases of hydrogen fluoride and ammonia. For these substances, high absorption effectiveness in pure water has enabled the technology to be included among the most advantageous methodologies in toxic hazard mitigation. Unfortunately, hydrogen sulphide is not absorbable in pure water, so that the application of fluid curtains would entail specific conceptual, design and operational aspects, in order for this technology to meet the same level of effectiveness attained for other toxic gases, especially when hydrogen sulphide concentrations are significant. This specific application has been dealt with to a very limited extent in the literature and no applications are reported at industrial level. Based on the elaboration of chemiabsorption absorption experimental data provided by van Krevelen et al. (1948), and by Astarita and Gioia (1964), this paper analyses and specializes the application of Fthenakis’ model to hydrogen sulphide absorption in carbonate solutions, investigating and implementimg in full detail the available experimental data of chemisorption and the related fluid-dynamic aspects. A case study shows the high effectiveness of the technique, provided that chemistry and fluid dynamic aspects are fully identified and addressed in the design.

The environment and the health of the masses are being affected by toxic gases such as O3, SO3, CH2O, H2S and HCN. In this study, we investigate the interaction of such toxic gases on SnS monolayer using density functional theory (DFT). The interaction between species and adsorbent is explained on the basis of their adsorption energy, electronic properties and charge transfer. Our results demonstrate that the process of adsorption of O3 and SO3 is chemisorbed in nature whereas CH2O, H2S and HCN is physisorbed. The validity of the adsorption process is further confirmed within the frame of electronic properties and charge transfer. As a result, we find each of the investigated gas molecules is acting as a charge acceptor. Diversity in the adsorption of customary gas molecules on the SnS monolayer gives rise to a possibility to exploit them as chemical gas sensors.

Highly sensitive and selective chemical sensors are needed for use in a wide range of applications such as environmental toxic gas monitoring, disease diagnosis, and food quality control. Although some chemiresistive sensors have been commercialized, grand challenges still remain: ppb-level sensitivity, accurate cross-selectivity, and long-term stability. Metal-organic frameworks (MOFs) with record-breaking surface areas and ultrahigh porosity are ideal sensing materials because chemical sensors rely highly on surface reactions. In addition, MOFs can be used as a membrane to utilize their unique gas adsorption and separation characteristics. Furthermore, the use of MOFs as precursors to enable facile production of various nanostructures is further combined with other functional materials. Based on these fascinating features of MOFs, there have been great efforts to elucidate reaction mechanisms and address limitations in MOF-based chemiresistors. In this review, we present a comprehensive overview and recent progress in chemiresistive sensors developed by using pure MOFs, MOF membranes, and MOF derivatives.

For serious accidents such as toxic/flammable release, fire and explosion in chemicals-concentrated areas, one primary issue is to evacuate on-site workers from potential affected zones. In this paper, based on corresponding reports, photos and videos, some accidents involving emergency evacuation are firstly investigated to present important and interesting problems to be considered in practice. These problems are summarized into three kinds of aspects including the poor efficiency of emergency plans, the low accuracy and high time-consuming calculation for evacuation route planning, and the neglection of evacuee's behavior and decision-making. Two main factors influencing the behavior and decision-making of evacuees are concluded as potential risk and impact from hazard sources, and the visibility at different locations. Then, the literature with respect to the emergency evacuation under toxic gas leakage, fire and visibility-limited conditions are reviewed. The key problems are related to ignoring the time-consuming requirement in emergency activities and domino effects of accidents, and the oversimplification of corresponding models. At last, from the famous cellular automata (CA) for emergency evacuation and atmospheric dispersion, a new general research framework for evacuation in chemicals-concentrated areas is proposed. It relies strongly on the quantitative assessment of risk, the establishment of individual visibility field, the use of CA coupled with artificial neural networks, and the optimal route planning. This paper could be useful for realistic problems on emergency evacuation in chemicals-concentrated areas.

Here, we present a facile ultrasonic-assisted method to fabricate hollow mesoporous silica spheres. The prepared hollow mesoporous silica spheres own well-regulated size, large specific surface area, and homogeneous mesoporous. Time-dependent experimental results depict that the formation of the hollow spheres undergoes a selective etching process. The results of fire toxic tests show that the toxic gases decomposed from the combustion of epoxy resin were observably inhibited with the incorporation of hollow mesoporous silica.

Source identification is critical for emergency responses to hazardous chemical releases, especially sudden releases of toxic gases. The timely arrangement of multiple sensors at the scene of a sudden accident is difficult. To overcome this limitation, a two-step source identification method based on a single sensor was developed. In the first step, the measured concentration was transmitted to the computing platform. First, a preliminary estimation of the release source was calculated from recently detected concentrations. Then, the preliminary result was used to predict the concentrations and to assess whether more measurements were needed. This data processing was conducted by the computing platform. In the second step, a new objective monitoring point was transmitted to the detector for the measurement of additional concentrations. These two steps were conducted repeatedly until the estimation adequately represented the release source. The fixed and mobile single sensor results were analyzed, and a comparison to multi-sensor results was also conducted. The results show that single-sensor source identification is attainable with a sufficient number of observations, and the number of valid concentration observations is required to be no less than the number of unknown parameters. To best estimate the release source, the movement strategy of the single sensor was based on the possible release source and the hazard partition of the gas plume. It is highly recommended that the single-sensor source identification method be used in unexpected incidents due to its flexibility and timely response.

The objective of this study was to develop a method for analyzing harmfulness of combustion products generated from material burning based on quantitative analysis. We conducted animal exposure experiment and performed quantitative analysis to analyze harmfulness of combustion products generated by material burning. Results of the experiment confirmed the limit of hazard analysis by toxicity index based on quantitative analysis of toxic gases. In the process of calculating harmful index of combustion products, we confirmed that the hazard of particulate matter should also be reflected. We also confirmed that existing criteria for judging harmfulness should be improved based on the amount of particulate matter generated. Results also confirmed that particle size and hazardousness of particulate matter were highly correlated. Results of this study demonstrate the necessity to study complex harmful analysis including particle size of particulate matter in the field of harmfulness of combustion products from material burning.

It is known that air pollution is responsible for causing numerous respiratory problems in the population, and in critical situations can even lead people to death. Because of this, a study was started here to analyze the amount of carbon monoxide (CO) and carbon dioxide (CO2), which cars that run daily on a highway near the city of Lorena-SP-Brazil scatter through the air. From a study carried out using the software COMSOL Multiphysics® three different situations (geometries) will be simulated numerically and a discussion will be presented. Keywords: Atmospheric pollution, Numerical simulation, COMSOL Multiphysics®

The interaction behavior and sensing ability of cyanogen chloride (CNCl) molecules on blue phosphorene nanosheet (βP-NS) were explored using first-principles calculation. The geometric stability of both pristine and Al incorporated βP-NS are established by the formation energy. The core stimulus of the current research is to probe hazardous CNCl gas molecules using βP-nanostructures rapidly. The interaction of various orientation sites of CNCl on βP-base material is investigated in association with the adsorption energy, average band gap changes, band gap, and Bader charge transfer. Furthermore, the exothermicity of adsorption energy is perceived upon the interaction of CNCl gas on βP-material, which varies from −0.151 to −0.653 eV. The findings of the proposed research recommend that the βP-NS can be employed for fast probing of CNCl toxic gas molecules and the sensing ability of CNCl improves with the substitution of Al in βP-nanosheets.

The exhaust gases, including SO2, NH3, H2S, NO2, NO, and CO, are principal air pollutants due to their severe harms to the ecological environment. Zeolites have been considered as good absorbent candidates to capture the six exhaust gases. In this work, we performed grand canonical ensemble Monte Carlo (GCMC) simulations to examine the capability of 95 kinds of all-silica zeolites in the removal of the six toxic gases, and to predict the adsorption isotherms of the six gases on all the zeolites. The simulation results showed that, H2S, NO, NO2, CO and NH3 are well-captured by zeolite structures with accessible surface area of 1600–1800 m2·g− 1 and pore diameter of 0.6–0.7 nm, such as AFY and PAU, while SO2 is well-adsorbed by zeolites containing larger accessible surface area (1700–2700 m2·g− 1) and pore diameter (0.7–1.4 nm) at room temperature and an atmospheric pressure. However, at saturated adsorption, zeolites RWY, IRR, JSR, TSC, and ITT are found to exhibit better abilities to capture these gases. Our study provides useful computational insights in choosing and designing zeolite structures with high performance to remove toxic gases for air purification, thereby facilitating the development and application of exhaust gas-processing technology in green industry.

Background Children in child care settings have a high infectious burden. They are frequently exposed to sanitizing and disinfecting agents, whose toxicities have not been studied in these settings. Current guidance on the preferred disinfection agents for child care is vague. Methods This article combines 2 different sources of information: the Environmental Protection Agency registration data on the efficacy of hospital-grade disinfectants and a review of the research on the toxicities of the most common of these disinfectants to summarize information that could be used for more evidence-based early care and education disinfection regulations and guidelines. Results Coverage of these organisms varied both between disinfectant classes (defined by active ingredient), as well as within classes. The 3 most common active ingredients in the database—quaternary ammonias, bleaches, and hydrogen peroxides—had 251, 63, and 31 products, respectively. Quaternary ammonias and bleaches are both known asthmagens, with the potential for toxic gas release when mixed. Quaternary ammonias may also cause reproductive toxicity. Disinfectant-grade peroxides have relatively low inhalational toxicity. Conclusions A clear rationale is needed to establish policies for determining preferable disinfection products for use in child care settings, based on efficacy against relevant pathogens, toxicity, ease of use, and cost. When other factors are equal, the use of peroxide-based disinfectant products is recommended to minimize inhalational toxicity.

It is vital to have high sensitivity in gas sensors to allow the exact detection of dangerous gases in the air and at room temperature. In this study, we used 2D MXenes and MoS2 materials to create a Ti3C2–MoS2 composite with high metallic conductivity and a wholly functionalized surface for a significant signal. At room temperature, the Ti3C2–MoS2 composite demonstrated clear signals, cyclic response curves to NO2 gas, and gas concentration-dependent. The sensitivities of the standard Ti3C2–MoS2 (TM_2) composite (20 wt% MoS2) rose dramatically to 35.8%, 63.4%, and 72.5% when increasing NO2 concentrations to 10 ppm, 50 ppm, and 100 ppm, respectively. In addition, the composite showed reaction signals to additional hazardous gases, such as ammonia and methane. Our findings suggest that highly functionalized metallic sensing channels could be used to construct multigas-detecting sensors that are very sensitive in air and at room temperature.

This paper aims to measure and analyse the realtime levels of toxic gases. In order to ensure safety of the workers working under such severe conditions. This project attempts to device an IOT technology that shall detect the humidity, temperature levels and mixture of gases, sensing each type of gas to measure its level while keeping track of the real-time dynamic changes in the above factors. If levels exceed beyond threshold, it shall send an alert on the connected mobile devices of the authorised people who are remotely located in the job. If any blockage is encountered, it can be monitored with the help of live video streaming.

In this work, a novel ZnO NWs based e-nose has been developed and demonstrated successfully for its ability to discriminate H2S and NO2 test gases. For this, a MS was fabricated by modifying the surface of the ZnO NWs with suitable sensitizers (∼

Off-gassing and self-heating are the major challenges when it comes to transportation and storage of wood pellets. The heat generated due to self-heating poses a fire risk while off-gassing of toxic gasses such as carbon monoxide (CO) and some volatile organic compounds (VOCs) is an environmental and human health risk. With the increase in production volumes of wood pellets which has subsequently increased the amounts of wood pellets in transportation and storage, there is need to find lasting solutions to off-gassing and self-heating of wood pellets. The objective of this study was to test the off-gassing abilities of Scots pine wood pellets produced from sawdust with varying amounts of extractives. The aim is to come up with raw material pre-treatment measures so as to produce wood pellets that are not liable to off-gassing. Six (6) types of sawdust raw materials namely; fresh pine sawdust (FPS), stored pine sawdust (SPS), sawdust plus pine rosin (PRS), sawdust plus linseed oil (LOS), sawdust plus tall oil (TOS) and acetone extracted sawdust (AES) were used to produce the pellets. The produced pellets were then subjected to off-gassing tests under controlled conditions using the ECOM J2KN analyser. The concentrations of carbon monoxide, carbon dioxide and methane increased with storage time but slowed down towards the end of the nine days test period. The formation of these gasses were largely dependent on the type of extractives present in the raw material and not the total extractive content. The formation of methane started later than the other gases and coincided with the time when residual oxygen was depleted.

Hydrofluorocarbon-based (HFC) fire extinguishing agents generate hydrogen fluoride (HF) gas [HF(g)] during thermal decomposition. Potential HF(g) exposure represents a health risk to any personnel not wearing proper Personal Protective Equipment (PPE) during scenarios where HFC extinguishers are deployed. HF(g) is harmful to humans at vapor concentrations greater than 3 parts per million (ppm), with an Immediately Dangerous to Life and Health (IDLH) level of 30 ppm. Controlled live-fire tests with HFC fire suppression confirm that HF(g) is produced at concentrations that greatly exceed IDLH levels within seconds and demonstrate the need for real-time detection of HF at high concentrations and within very short time frames. Current commercial sensors are limited in capability for measuring high concentrations of HF in the vapor phase, and within the time frame required to prevent exposure to dangerous levels of this toxic gas. This review provides a comprehensive overview of HF detection methods, including colorimetric, electrochemical, mechanical, and optical sensors. The applicability of sensor types to HF detection within the complex environment of a fire event is evaluated regarding response time, selectivity, and sensor saturation.

Toxic gas leak accidents can lead to significant casualties. The damage from a leak accident will be greater if toxic gas spreads to places where population density is high or vulnerable facilities with people who have difficulty evacuating. And the damage from leak accidents will also be greater if there is no evacuation warning from the plant despite the significant leak. Therefore, it is necessary to design the fenceline monitoring system through sensor placement optimization that reduces the risk toward the community. In this study, a mixed-integer linear programming formulation is proposed for sensor placement minimizing the risk by reflecting the characteristics of nearby areas. In order to quantitatively estimate the risk toward the community, the risk is calculated using dispersion data from computational fluid dynamics simulations and evacuation vulnerability and population density that define characteristics of a community. A case study is conducted to validate the efficiency of the proposed method. Exposed area and residual risk fraction are compared according to sensor placements from different conditions. Top-3 risk leak scenarios are analyzed quantitatively to manage the worst leak accident. It is validated that the proposed method is more efficient especially for the community that has uneven characteristics distribution.

In this study, based on first principles calculations, we compared the performance during the sensing of toxic gas molecules (NO, NO2, HCN, and NH3) by Mo, Si, and Pt dopants within BC3 sheets (D-BC3). Compared with the Pt-BC3 sheet, the Si-BC3 and Mo-BC3 sheets exhibit a stronger affinity for the adsorption of gas molecules. The adsorbed NO and HCN had larger energy differences than those of the NO2 and NH3 molecules, thereby indicating that NO2 and NH3 could be detected readily as specific gas molecule on the D-BC3 substrates. In addition, the adsorption of gas molecules induced great changes in the electronic structure and magnetic properties of the D-BC3 systems. In particular, the adsorption of NO on the Pt-BC3 and Si-BC3 substrates yielded a larger magnetic moment (2.0 μB) than those when the other gases were adsorbed on D-BC3 sheets. These results may facilitate control over the adsorption properties of toxic gas molecules and the design of BC3-based gas sensors or spintronic devices.

In recent years, the search for efficient catalysts to oxidize nitrogen gas (N2) and chlorine monoxide (ClO) has acquired high industrial importance. The present study proceeds in two steps. In the first, Ge atoms are adsorbed on B36N36 and C72 clusters, and the Ge B36C36 and Ge C72 surfaces are activated by reactions with O2 molecules. In the second, the oxidation of N2 and ClO on the Ge B36N36 and Ge C72 surfaces is investigated. It is found that O2 Ge B36N36 and O2 Ge C72 can oxidize N2 and ClO molecules, respectively. Significantly, oxidation of N2 and ClO molecules by Ge B36N36 and Ge C72, respectively, proceeds in two-step reactions. From the present calculations, Ge B36N36 and Ge C72 are high-performance catalysts for N2 and ClO oxidation, respectively.

The latest IMO regulatory requirements concerning the control of toxic gas emissions from ships have sparked interest in whether ships are adequately equipped to operate safely in adverse weather conditions when compliance is achieved simply by the reduction of power. This paper deals with the analysis of navigational accidents (collision, grounding, and contact accidents) that occurred in adverse weather conditions and may have been related to the lack of sufficient powering and manoeuvrability. The analysis aims to potentially assist the IMO regulatory work in setting rational margins of minimum powering of ships for safely operating in adverse weather conditions.

Nitrogen dioxide (NO2) is one of the toxic gas that causes debilitating disease in the respiratory system. Due to imprudent industrial development, the need for a facile and sensitive gas detection has been grown. Here, we develop a simple and disposable NO2 gas sensor employing carbon adhesive tape (CAT) as the gas detection element. The CAT developed in this study contained a large amount of carbon black material to adsorb NO2 gas molecules. Experiments revealed that the gas molecules were bound rapidly to the CAT sensor (

Being a significant part of waste electrical and electronic equipment (WEEE), computer waste is gaining more attention due to its tremendous generation and toxic environmental concerns. The complex and diverse material content in the computer makes them ideal for recycling. At the same time, presence of hazardous contents such as flame retardants and heavy metals makes obstructions in recycling procedure. An enormous amount of computer wastes are either landfilled or incinerated, which results in leaching of chemicals and emission of toxic gases respectively. This paper reviews the information related to the role of computers in WEEE stream, hazardous components in computer waste stream, possibilities of segregation and the recycling of different components of the computer waste. A methodological segregation and recycling of the computer waste components is more economical as compared to landfilling and incineration. Ultimately, natural petroleum resources can be conserved by recycling waste products which leads to the sustainable development of novel products. Furthermore, this review is helpful to sustainable development, in recycling procedure product formulation from computer waste products.

The optimized atomic structures, energetics and electronic structures of toxic gas CO adsorption systems on pristine, C-doped and N-vacancy defected h-AlN nanosheets respectively have been investig ...

The effects of support on gas adsorption is crucial for single atom catalysts design and optimization. To gain insight into support effects on gas adsorption characteristics, a comprehensive theoretical study was performed to investigate the adsorption characteristics of toxic gases (NO2, NH3, SO3 and H2S) by utilizing single atom iron catalysts with three graphene-based supports. The adsorption geometry, adsorption energy, electronic and magnetic properties of the adsorption system have been explored. Additionally, the support effects have been analyzed through d-band center and Fermi softness, and thermodynamic analysis has been performed to consider the effect of temperature on gas adsorption. The support effects have a remarkable influence on the adsorption characteristics of four types of toxic gases which is determined by the electronic structure of graphene-based support, and the electronic structure can be characterized by Fermi softness of catalysts. Fermi softness and uplift height of Fe atom could be good descriptors for the adsorption activity of single atom iron catalysts with graphene-based supports. The findings can lay a foundation for the further study of graphene-based support effects in single atom catalysts and provide a guideline for development and design of new graphene-based support materials utilizing the idea of Fermi softness.

Gas storage and separation are closely associated with the alleviation of greenhouse effect, the widespread use of clean energy, the control of toxic gases, and various other aspects in human society. In this review, we highlight the recent advances in gas storage and separation using metal-organic frameworks (MOFs). In addition to summarizing the gas uptakes of some benchmark MOFs, we emphasize on the desired chemical properties of MOFs for different gas storage/separation scenarios. Greenhouse gases (CO2), energy-related gases (H2 and CH4), and toxic gases (CO and NH3) are covered in the review.

Metal-organic frameworks (MOFs) have been rapidly developed in the fields of gas adsorption and storage, but are unsatisfactory in NH 3 adsorption due to their unstable structures. Considering NH 3 is both a toxic gas and the only carbon-free chemical energy carrier, MOFs exhibit great prospects for the adsorption and storage of NH 3 due to their advantages of structural diversity, modifiable structures and high surface area. In this work, we have researched, in detail, the structural characteristics, stability and NH 3 adsorption properties of MIL-53, NH 2 -MIL-53, MIL-100 and MIL-101. In addition, the NH 3 adsorption sites have been investigated using Grand canonical Monte Carlo simulations. The results showed that MIL-100 and MIL-101 have a large NH 3 uptake of 8 mmol/g and 10 mmol/g, respectively, and that the modified amino functional groups improve the NH 3 adsorption capacity in NH 2 -MIL-53. More importantly, the four MIL materials have reusable NH 3 uptake and excellent NH 3 (and NH 3 /H 2 O) stability, and are promising materials for NH 3 adsorption.

The increase in the number of vehicles causes the air pollution in cities to be increased. Thus, evaluation of the actual level of traffic emissions has gained more interest. Driving cycle is one of the most important parameters affecting exhaust emissions. In this study, driving cycle on arterial roads in Mashhad, Iran was compared with standard driving cycles in Europe and America. After development of the driving cycle, vehicle exhaust emissions were estimated by the international vehicle emissions (IVE) model. In order to correct the emissions obtained from the model, on-board vehicle emissions were obtained. The emission factors estimated for Mashhad were compared with those reported for Beijing, Pune and Mexico. The speed-time data of vehicle was obtained in two weeks for two different routes. The driving cycle showed the average speed in Mashhad was significantly different with that in the European and American driving cycles. The results of the model showed CO in vehicle exhaust constituted the most emission of criteria pollutants. Moreover, ammonia and benzene were the main toxic gases in vehicle exhaust, respectively. By considering the vehicle exhaust emission factors, CO produced in Mashhad was 10.5, 30.69 and 25.67% more than Pune, Mexico and Beijing, respectively.

Emergency evacuation plan plays a key role for fire risk management and successful evacuation. In this work, a topological model of evacuation routes is established and the corresponding matrix function is also proposed in order to evaluate evacuation ability. Simultaneously, risk assessment of fire scenarios is made based on numerical simulation. And on this basis, the variation laws of risk indicators such as temperature, thermal radiation, the concentration of toxic gas are analyzed in details and dynamic risk assessment of evacuation routes is made. Introducing the concept of equivalent routes, the scheme of the best route for evacuee at each location is the one along with the shortest time and minimal risk and suggested based on the Dijkstra algorithm. And then, one case is presented and result indicates that this model can aid people to avoid crowdedness and evacuate as soon as possible under fire accident. The risk-based model is also useful for the evacuation planning.

Environmental detection, monitoring and controlling of pathogenic or harmful gases has become an utmost priority. They contribute to major public health problems such as respiratory diseases, cardiovascular dysfunction and diseases, central nervous system (CNS) anomalies and other diseases (cancer, bronchiolitis, asthma etc.). Also, they are associated with frightening global warming thus affecting the ambient environment. Therefore, there is an urgent need to control and mitigate these gases. Notably, the existing conventional gas sensors are painstakingly very slow, labour and capital intensive, invasive and require specialized apparatuses and human capital to operate. A glowing need to develop cheap, fast, efficient, highly sensitive, portable sensors with less power usage and a high degree of reliability has been on the rise. Carbon nanotubes (CNTs) have been extensively explored to develop biosensors owing to fact that they are tubular-nanosized materials with excellent biocompatibility coupled with large surface area, excellent thermal, electrical, mechanical and optical properties. In the recent past, the invention and fabrication of CNTs-based biosensors and their mechanisms have been a subject of intense research studies in the detection and monitoring of gases. Therefore, in this short review, we present an in-depth overview survey of CNTs-based biosensors for gas sensing sourced from published papers and online articles. The paper also highlights challenges associated with CNTs-based gas sensors, possible remedial actions and future work opportunities in this research area.

Cyanide gases are colorless and toxic gases, which are widely used in the industry, thus efficiently detecting them has become a pressing issue. The sensitivity and selectivity of β-tellurene toward cyanide gases are reported in this work. Adsorption energy, charge transfer, and electronic properties of the cyanide gases (HCN, (CN)2, CNBr) as well as common gases (CO2, N2, CO) adsorption systems are calculated based on the density functional theory (DFT). The significantly larger adsorption energy (−0.26 eV for HCN, −0.36 eV for CNBr) and charge transfer (0.11 |e| for HCN, 0.10 |e| for CNBr) show that the tellurene is a well sensitive material for cyanide gases detection. The change of I–V curves made by gas adsorption further confirms the selectivity and sensitivity of tellurene to cyanide gases, especially the HCN. Moreover, different biaxial strains could effectively regulate the adsorption behavior of cyanide gases on tellurene, as the adsorption energy of the HCN molecule is enhanced to be −0.52 eV. Based on these results, we predict that tellurene could be a practical material to detect cyanide gases.

In this paper, a room temperature operable, highly reproducible, stable and selective ammonia gas sensor of PVP, WO3, and PVP/WO3 nanocomposites were investigated. Drop casting method was used to deposit the sensing materials on interdigitated copper electrode. Chemical reduction and ultrasonication methods were adopted for the preparation of WO3 and PVP/WO3 nanocomposites, respectively. The as-produced sensing materials were characterized by using FTIR, XRD, and SEM techniques. LCR meter was used to analyze the gas sensing properties of PVP, WO3 and PVP/WO3 (5–25 wt%) nanocomposites. Under same condition of temperature (300 K), humidity (40%RH), and NH3 vapors (100 ppm) the sensor based on PVP/WO3 20 wt% showed higher sensing response of 87.26 as compared to pure PVP and WO3 nanosheets sensor which was 15.36 and 3.37, respectively. The PVP/WO3 20 wt% based sensor exhibited excellent results in term of reproducibility, stability (90 days), response time (14 s), and recovery time (10 s).

The novel rGO/Ti3C2Tx heterostructures were prepared from Ti3C2Tx MXene and rGO via a simple ultrasonication method. From the morphological and structural analyses, it was confirmed that the MXene and rGO were well-hybridized with sharp interface and substantially increased surface area. Owing to its microstructural advantage and high surface functionality, a standard rGO/Ti3C2Tx heterostructure showed sharp, large, concentration-dependent, and cyclic response curves to NO2 gas at room temperature. Furthermore, the heterostructure also exhibited response signals to other types of toxic gases like methane and toluene. This gas-sensing performance was far better than those of MoS2/Ti3C2Tx and g-C3N4/Ti3C2Tx heterostructures, which were synthesized for comparison. The results of this work may give an insight into realizing an efficient, multigas-detecting, and room-temperature-operable gas sensor.

Toxic gas CO has attracted great attention due to their strong impact on human health. Here, CO reaction in CO oxidation was used to treatment catalyst and add a new application. Satisfactorily, highly uniform and well dispersed octahedral CuO/Cu 2 O composite derived from CuBTC is successfully synthesized, which still retain the original morphology of the MOFs. Moreover, CuO/Cu 2 O composite showed an excellent catalytic performance, which was ascribed to the higher Cu 2 O/CuO ratio, good low temperature reduction behavior and a high quantity of surface active oxygen species. Importantly, this simple method reported in this work can be universal and facilely expand to other metal oxides, synthesizing diverse MOFs based metal oxides.

Carbon monoxide (CO), a highly toxic gas, is now well known as an important gasotransmitter in living systems. Accordingly, development of fluorescent probes for CO is of great significance. However, fluorescent detection of CO in living systems is challenging due to the lack of effective probes, and particularly, ratiometric fluorescent probes for CO have not yet been reported. In this article, a readily available colorimetric and ratiometric fluorescent probe system for CO was reported. This probe system shows excellent sensing properties for CO including rapid response, high selectivity and sensitivity with a low detection limit (58 nM), and capable of giving distinct colorimetric and ratiometric fluorescent signal changes for CO in aqueous solution under mild conditions. In addition, this probe system has low cytotoxicity and can be used to ratiometrically detect CO in living cells. Furthermore, a very convenient paper test strip system can be developed with this probe for visual detection of CO gas. Overall, this work provided a very promising probe for colorimetric and ratiometric fluorescent detection of CO in air, aqueous solution, and living cells.

Several opinions are presented that underground coal gasification (UCG) may be used at large scale in coal seams of low thickness, at a great depth and for unrecovered coal in abandoned mines. Geological features of coal deposits limits wide application of UCG. The most important factor for safe UCG is the isolation of coal seam by the sufficiently thick seal of impermeable rocks, preventing the escape of toxic gases and substances (CO, phenols etc.) into the environment. There should be no faults and the minimum coal seam thickness of at least 1.5 m of sub-bituminous or low rank bituminous coal is advised for UCG. The most of low rank lignite (soft brown coal) deposits in Poland are unfavorable for UCG, due to the lack of sufficient isolation from water bearing rocks and nature conservation exigencies. About 10% of resources below 100 m depth may be suitable for underground gasification, however the high lignite moisture close to 50% can make it difficult. The detailed evaluation of hard (bituminous) coal resources in Poland explored up to 1.000 m depth, and careful selection of possible UCG sites has demonstrated that only about 10% of it may be gasified underground, and 6–7% not disturbing conventional coal mining. The great challenge is the underground gasification of deep seated thick coal seams, below 1.000 m, inaccessible for traditional mining as a rule, after conventional extraction of resources at lesser depth. It makes UCG promising mode of future coal utilization. More detailed study of coal gasification in varied real geological environment is necessary however.

1. Abstract Chelating agents were introduced because of the several issues associated with inorganic acids during oilfield stimulation. Carbonate and sandstone rocks have been stimulated using different kinds of acid systems and there is an engaging debate on chelating agents as an effective acid system. Several shortcomings of inorganic acid systems need to be addressed by chelating agents in order to be its constructive replacement. The complex nature of these chelating agents led to accelerated research and developmental efforts in understanding its applicability at different environmental conditions. The past two decades of research in chelating agents for oilfield stimulation has resulted in researchers branching out in several directions to realize the potential of this acid system. There is a requirement to link these branches and provide a holistic view of the lessons learned during this time. Various researchers have also provided guidance for future work that is commonly disregarded. This paper provides a nexus of the research conducted in this field and could direct plans for future research. Hydrochloric acid for carbonate acidizing and mud acid for sandstone damage removal have been found to cause issues such as face dissolution, reaction product precipitation, chemical incompatibility, high corrosion rates, toxic gas generation, emulsion issues, amongst many others. The recent interest in chelating agents led to researchers conducting tests to understand its interactions with the formation rock and other oilfield fluids. Experiments such as coreflooding, corrosion tests, compatibility, Inductively Coupled Plasma (ICP), Environmental Scanning Electron Microscope (ESEM), and X-Ray Diffraction (XRD) helped in highlighting the advantages of chelating agents. From these studies, researchers were able to find synergistic blends that could help improve traditional treatment practices. Mechanisms of chelating agent reactions with sandstone and carbonate rock were elucidated in this work. The future outlook of chelating agents' application lies in making the treatment more cost-effective, environmentally friendly, and target focused. Chemical formulations must be designed to take advantage of high-temperature stability, low reprecipitation potential, low sludging tendency, high dissolving capacity, high iron controlling potential, and low corrosion rates offered by chelating agents. Some field experiences were noted, which could encourage operators to perform more such treatments in the future. The reader of this review article would gain knowledge of the complex chemistry of chelating agents and describes the research done for acid stimulation and iron control. Through the process of review, the paper also connects the wealth of research in this field and provides a measured guidance for technology development to promote the use of chelating agents in the industry. It can help future researchers in academics or the industry to enhance the quality of research.

Epoxy resin has been widely used in aerospace, automotive construction and other fields due to its excellent mechanical performance, dielectric and corrosion resistance properties. However, epoxy resin can burn easily in the air and create the massive hazardous smoke and toxic gases during combustion, which may bring casualties and property losses, and limit its range of usage. It is therefore necessary to improve its flame retardant performance by using various flame retardants. Graphene and its derivatives have unique lamellar structure and can endow epoxy resin with good flame retardancy properties through the barrier effect of “tortuous path”. In this wok, the recent research progress of graphene and its derivatives flame-retardant epoxy resin, and flame-retardant mechanism were systematically introduced. Moreover, the problems faced by flame-retardant epoxy resin and its development prospects have been analyzed. We hope that this review can provide valuable reference and inspiration for the researchers in this field.

Funding Information: We thank Glen Forde from Aalto Energy Platform for his design work for Figs. 2 and 6. Kati Miettunen thanks The Academy of Finland (project BioEST, 336577). Publisher Copyright: © 2021 Recycling is rarely considered in the field of dye solar cells. However, recycling should be a critical part of holistic eco-design, which considers the efficiency, lifetime, return of energy investment, safety, and availability of materials. The novelty and focus of this work is recycling, and this is the first contribution systematically analyzing how different material choices and their combinations affect the recycling of dye solar cells. By understanding the recycling processes and how the recycling of materials is interlinked in a multicomponent system, it is possible to eco-design systems and guide future research toward selecting materials that support sustainability and enable economically motivated recycling. Economic incentive is the biggest factor determining whether or not recycling will take place. With eco-design, it is possible to avoid future problems, such as trapping rare and expensive critical metals in waste from which they are difficult or even impossible to recover. In fact, the conventional dye solar cells create harmful waste with no economically profitable way of recycling. Interestingly, many of the alternative materials that enable recycling have not been originally designed for that purpose, and it is rarely obvious how the combination of different materials affects recycling. For instance, using thin flexible substrates, which have been developed for roll-to-roll manufacturing, supports the retrieval of Ag, and using high performance Co- or Cu-based electrolytes instead of iodine electrolyte eliminates toxic gas problems in pyrometallurgical recycling processes.

Gas detection is attaining significant attention in the healthcare sector due to the health issues involved with the inhalation of toxic gases present in the air. Though the existing sensors can efficiently detect the target gases, they suffer from high power consumption, interference with other gases, and baseline drift. Here, we present a drift-independent technique to achieve selectivity and low power consumption with a single unfunctionalized metal oxide gas sensor. We utilized adsorption-desorption noise to discriminate H2S from NH3 and CO2. As it addresses typical challenges of existing resistive gas sensors, the proposed methodology paves the way for developing future low-power selective gas sensing technology.

Hydrogen sulfide (H2S) is a very toxic, flammable, and harmful gas. It may be formed naturally or be released into the environment due to human activities. Exposure of humans to a high level of H2S leads to many hazardous effects. On the other hand, H2S is produced in vivo and it has many physiological actions as the third physiological gas transmitter. Therefore, it is crucial to develop sensitive, selective, and easily operated sensors to monitor H2S in its two-sided nature as toxic gas and as a physiological gas transmitter. Recently, the revolution in nanotechnology has a great impact on the development of many sensing techniques that adopt nanosensors for the detection of H2S. Herein, we abridged the nanostructure-based electrochemical and optical sensors for H2S in different matrices with a special emphasis on their advantages and applications. A discussion of the sensing mechanisms and the analytical features are also addressed. Finally, the future perspectives and recommended trends for H2S detection are discussed.

The present study aims at a real-world assessment of the driving behaviour and exhaustive emission performance of motorcycle (MC) driving in a middle-sized city of a developing country, i.e. Isfahan, Iran. We developed the Isfahan Motorcycle Driving Cycle (IMDC) using comprehensive data collection and then compared it with the available overseas MCDCs and DC of local LDVs. Onboard experiments were also conducted on 20 test motorcycles to analyze emission performance, emission characteristics, and combustion quality of motorcycles under real-world conditions. IVE model was used to estimate the MC emission factors (EFs) according to the real-urban conditions, but it was first adjusted to the real-world measurements. Results show that MC EFs steadily decrease with vehicle speeds. Apparent discrepancies were observed between IMDC and the MC DCs overseas, while local DCs of motorcycles and LDVs follow a prevailing trend determined by the new factors of public culture and urban development. CO was the major criteria pollutant of the MCs exhaust, and formaldehyde and benzene were ranked as the first and second principal toxic gases, respectively. The air-fuel mixture control system and combustion quality of 150 and 200 cc MCs were impaired with the vehicle speed, but the same is not true for the 125 cc MCs.