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The green and pollution-free mining of resources has always been a research field that people have focused on. In the process of mining resources, the production of CO, SO2 and other pollutants directly affects the health of miners and the atmospheric environment in the mining area. Therefore, it is particularly important to deal with and control the polluting gases generated by mining. Taking the underground roadway of a coal mine in Hengdong City, Hunan Province, as the research object, we studied the migration law of pollutant gas there. Comsol software was used to determine the changing state of pollutant gas migration in the roadway, and a simulation model of the wind field and the pollutant concentration field in the roadway under turbulent conditions was established. The results showed that, when the air flow moved to the front face of the roadway, it generated backflow to form a counterclockwise-rotating air flow vortex. Here, the air flow stagnated, hindering the diffusion of pollutants. The gas moved with the air flow in the roadway, and the flow’s velocity decreased in the middle of the roadway, causing pollutants to accumulate. The whole wind field tended to be stable at a plane 25 m from the roadway’s outlet. This indicates that the middle part of the roadway is the place where the polluted gas accumulates, and it is of representative significance to study the concentration of the polluted gas in the roadway in this section.

Safety plays a major role into days world and it is necessary that good safety systems are to be implemented in places of industries, big manufacturing factories, education and work. This work modifies the existing safety model installed in industries and this system also be used in homes and office. The main objective of the work is designing microcontroller based toxic gas detecting and alerting system the hazardous gases like LPG and propane were sensed and displayed each and every second in the LCD display these gases exceed the normal level the nan alarm is generated immediately and also an alerting message (SMS) is send to the authorized person through GSM.

There have been studies recently on bubble-column scrubbers with low cost and high efficiency for the absorption and treatment of hazardous gases in the event of a chemical spill. Bubble columns are vulnerable to freezing at temperatures below zero because the absorbents generally do not circulate. To address this issue, this study focused on the applicability, absorbed amount, and performance of brine as an absorbent. Under three different temperatures, i.e., −5 °C, −8 °C and −10 °C we examined brine (NaCl, CaCl2, and MgCl2) by varying the concentration required at each temperature. Following the experiments, CaCl2 brine was determined as the optimal brine for its absorption performance and affordability. Based on the experimental results, the absorption performance for ammonia, ethylene oxide, and methylamine, which are hazardous and water-soluble gases among accident preparedness substances (APS), was tested by using ASEPN PLUS. Our results suggested although the efficiency dropped by about 5% to 25% when brine was used as an absorbent, it can be used at the low temperatures because the gas solubility increased with decreasing temperature. Therefore, if brine, as an alternative, is used at temperatures about 15 °C, it can operate efficiently and stably without deterioration in the absorption performance. Given our experimental results and design data on the absorbed amount and absorbent replacement period for major hazardous gases are utilized to prevent bubble columns from freezing, it can be commercially used for small and medium-sized enterprises because it can help reduce installation and operation costs.

In this work, we use the first-principles method to study in details the characteristics of the adsorption of hazardous NO2, NO, CO2, CO and SO2 gas molecules by pure and heteroatom (Ti, Si, Mn) modified Al60N60 nanoclusters. It is found that the pure Al60N60 cluster is not sensitive to CO. When NO2, NO, CO2, CO and SO2 are adsorbed on Al60N60 cluster&rsquo, stop.b, edge.ap, edge.ah, edge.ap andedge.ah sites respectively, the obtained configuration is the most stable for each gas. Ti, Si and Mn atoms prefer to stay on the top sites of Al60N60 cluster when these heteroatoms are used to modify the pure clusters. The adsorption characteristics of above hazardous gas molecules on these hetero-atom modified nanoclusters are also revealed. It is found that when Ti-Al60N60 cluster adsorbs CO and SO2, the energy gap decreases sharply and the change rate of gap is 62% and 50%, respectively. The Ti-modified Al60N60 improves the adsorption sensitivity of the cluster to CO and SO2. This theoretical work is proposed to predict and understand the basic adsorption characteristics of AlN-based nanoclusters for hazardous gases, which will help and guide researchers to design better nanomaterials for gas adsorption or detection.

Предприятия по производству животноводческой продукции являются серьезными источниками загрязнения окружающей среды. Это относится к загрязнению почвы, водных источников продуктами жизнедеятельности животных, а также газообразными выбросами в атмосферу. Выделяемые животными углекислый газ, метан, соединения азота, водяные пары, являются парниковыми газами, оказывающими серьезное влияние на изменения климата. Для снижения загрязнения атмосферы выбросами животноводческих ферм предлагается система конверсии газообразных вредных веществ с целью их дальнейшей безопасной утилизации. Система состоит из вентилятора подающего воздух из коровника, пылеуловителя, первой ступени конверсии газов, которая охлаждается с целью повышения растворимости газов воде. В первой ступени происходят химические реакции, в процессе которых образуются гидрокарбонат аммония и аммиачная вода, таким образом, аммиак и углекислый газ переходят в растворы, которые могут быть использованы для консервации кормов и как удобрения. Не вступившие в химические реакции сероводород и метан переходят во вторую ступень. В ней, с добавлением озона, из сероводорода образуется диоксид серы или серная кислота в зависимости от условий протекания процесса. Метан и диоксид серы в виде газа накапливаются и могут быть использованы для получения тепловой энергии путем сжигания. Система имеет на каждой ступени протекания процесса датчики, сигналы с которых поступают на центральный компьютер для анализа, и в зависимости от заданной программы, через блок управления, подаются соответствующие команды на охлаждение, подачу воды или катализаторов процесса. Система конверсии позволит снизить загрязнение воздушного бассейна в зоне фермы, устранить неприятные запахи и получить некоторое количество удобрений, консервантов и других веществ., Livestock farms are major sources of environmental pollution. This refers to pollution of soil and water bodies with animal life products, as well as gaseous emissions into the atmosphere. Carbon dioxide, methane, nitrogen compounds, and water vapor released by animals contribute greatly to climate change. To reduce the air pollution from livestock farms, a system for the conversion of harmful gaseous substances is proposed with a view to their further safe disposal. The system consists of a fan that supplies the air from the barn, a dust collector, the first stage of gas conversion, which is cooled to increase the water solubility of gases. At the first stage, ammonium bicarbonate and ammonia water are produced through chemical reactions; so ammonia and carbon dioxide are converted into solutions, which can be used as feed preserving agents and fertilizers. Hydrogen sulfide and methane, which have not entered into chemical reactions, pass to the second stage. Here the ozone is added and sulfur dioxide or sulfuric acid is formed from hydrogen sulfide, depending on the process conditions. Methane and sulfur dioxide in the form of gas are accumulated and can be used to produce the thermal energy by combustion. At each process stage the system has sensors, the signals from which are sent to the central computer for analysis; then, depending on the preset programme, the appropriate commands for cooling water or process catalysts supply are given via the control unit. The conversion system allows to reduce the air pollution around the farm, to eliminate the odour and to produce some fertilisers, preserving agents and other substances.

In recent years, many studies have focused on the application of advanced technology as a way to improve management of construction safety management. A Wireless Sensor Network (WSN), one of the key technologies in Internet of Things (IoT) development, enables objects and devices to sense and communicate environmental conditions; Building Information Modeling (BIM), a revolutionary technology in construction, integrates database and geometry into a digital model which provides a visualized way in all construction lifecycle management. This paper integrates BIM and WSN into a unique system which enables the construction site to visually monitor the safety status via a spatial, colored interface and remove any hazardous gas automatically. Many wireless sensor nodes were placed on an underground construction site and to collect hazardous gas level and environmental condition (temperature and humidity) data, and in any region where an abnormal status is detected, the BIM model will alert the region and an alarm and ventilator on site will start automatically for warning and removing the hazard. The proposed system can greatly enhance the efficiency in construction safety management and provide an important reference information in rescue tasks. Finally, a case study demonstrates the applicability of the proposed system and the practical benefits, limitations, conclusions, and suggestions are summarized for further applications.

In this paper, experimental and theoretical investigations on liquid spray curtains are presented, in the context of absorbing and dispersing hazardous gaseous releases. The problem of release mitigation by absorption, either in pure water or in aqueous solution, was investigated or analytically solved by developing a general approach. The structure of the model includes a fluid-dynamic model describing air entrainment rate both in still air and in windy conditions, an absorption model, predicting spray efficiency and a mixing-dispersion model for the evaluation of the overall barrier effectiveness in environmental control. The model was validated by means of replicated experimental runs in a wind tunnel equipped with spray nozzles suitable to create a two-blade barrier. The model agreement with experimental data was fairly good in both cases of water and reacting curtain, which is promising for short-cut design purposes. The developed framework can be applied to more complex situations and different gas, allowing, as well, the attainment of a more generalized approach for the design of a curtain, once given the release parameters, the site layout and the sensitive target specifications.

Monitoring of hazardous gases is nowadays very important, since the urbanized environment is more subject to this kind of pollutants. Therefore, a capillary network of small gas sensors capable to check the quality of the environment is necessary. Metal oxide gas nanosensors are small economic devices that can be easily integrated in any context, however they unfortunately lack of selectivity. We present an approach using hydrothermally grown nickel oxide nanowires working at different temperatures and creating a virtual sensors array, thus exploiting the thermal fingerprints (sensor response as a function of temperature) of the gases. Using only one nanostructured material (nickel oxide) and different machine learning techniques, the system can easily discriminate any of 7 harmful gases (C2H5OH, H2, CO, LPG, CO2, NH3 and H2S, all of them reducing gases) with an accuracy of 100%. Furthermore, the nanosensor also evaluates the gas concentration with an average error lower than 15%. Our results show that, exploiting thermal fingerprints from a temperature gradient, single metal oxide resistive nanosensors can efficiently discriminate specific hazardous gases.

Networked films of carbon nanotubes (CNTs) have been grown by CVD technology onto low-cost miniaturized alumina substrates. The sidewalls of the CNTs films have been modified by spray-coating with two different metalloporphyrins (MPPs) consisting of a TetraPhenylPorphyrin coordi-nated by a central metal of zinc (Zn-TPP) and manganese (Mn-TPP) for enhanced sensitivity and tailored specificity. Hazardous gases such as NO2, NH 3, H2S, SO2, and CO have been detected with various responsiveness in the range of concentration from 0.1 to 1000 ppm. The response of the chemiresistors in terms of p-type electrical conductance has been investigated as a function of the thickness of the functionalizing MPPs; and the effect of the temperature ranging from 20 to 150 °C on the sensor response has been addressed as well. A response of the CNT-sensor functionalized by 2 layers of Mn-TPP has been measured as 0.025% towards 0.5 ppm NO 2, at 150 °C.

不法投棄物や最終処分場の埋立廃棄物の掘削現場において，ハンディタイプオープンパス型メタン自動計測器によって連続計測したppmレベルの大気中メタン濃度を指標とする作業環境の有害ガス簡便モニタリング手法を提案し，掘削現場への適用可能性を検討した。不法投棄現場や最終処分場から発生するガス中の有害ガスはメタンと共存すること，有害ガスとして注目されるのは硫化水素である場合が多いこと，硫化水素のメタンに対する濃度比の最大値は10^[-1]程度であることを示し，大気中メタン濃度が発生ガス中の有害ガスの潜在的な危険性を安全側で評価する指標になることを明らかにした。また，掘削現場での影響が懸念される硫化水素等の有害ガスの許容濃度，有害ガスのメタンに対する濃度比の最大値および安全率を考慮して設定したメタン濃度の管理値を計測値と比較する提案手法が，掘削現場の安全管理のためのモニタリングに適用できることを示した。, We propose a convenient method for monitoring hazardous gas based on the determination of ppm-level concentrations of CH4 in ambient air. The proposed method can be applied during the excavation of landfill or dumped waste at reclamation sites, and we investigated its usability in an actual field. A portable open-path type analyzer and a retroreflector were used to determine the CH4 concentration. The hazardous gas in landfill gas emitted from final disposal and illegal-dumping sites always contains CH4 and H2S occurring together, with the latter considered to be the main hazardous component. The maximum concentration ratio (H2S/CH4) at final disposal and illegal-dumping sites was expected to be about 10^[-1]. This study showed clearly that the ambient CH4 concentration could be useful as an indicator for the monitoring of hazardous gas for the evaluation of potential danger. It was also shown that the proposed method could be useful for monitoring as a safety control at a reclamation site. This method works by comparing the measured ppm concentration levels of CH4 with a management value that is decided by considering the maximum concentration ratio (of the hazardous gas that was most harmful at the site, such as H2S/CH4), its acceptable concentration and a safety ratio.