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Active fault zones are critical pathways for the migration of deep fluids to the Earth's surface, carrying gases such as He, Rn, and CO2 that provide evidence for the physical and chemical dynamics of the Earth's interior. This review examines the geochemical characteristics of fault zone gases and their implications for understanding fault activity and seismic events. Fault zones with high activity levels exhibit significant gas release, and variations in soil and hot spring gas concentrations can serve as indicators of seismic activity. Changes in gas concentrations and isotopic ratios, particularly before and after earthquakes, reflect the dynamic interplay between deep-sourced and shallow-sourced fluids. Seismic-induced stress alterations enhance gas release along fault zones, leading to observable anomalies that can aid in earthquake monitoring and prediction. The study underscores the importance of isotope tracing in deciphering fluid sources, migration pathways, and the evolution of fault zones, providing valuable information for assessing tectonic activity and mitigating seismic risks. [ABSTRACT FROM AUTHOR]

This study examines the effects of methanol–diesel blends on the emissions of a diesel engine, concentrating on carbon monoxide (CO), carbon dioxide (CO2), nitrogen oxides (NOx), hydrocarbons (HCs), and particulate matter (PM). Using a single-cylinder four-stroke diesel engine at varying torque settings (2 N m–6 N m), significant reductions in CO, CO2, HC, and PM emissions were observed with increasing methanol content. CO emissions reduced by up to 81.8%, CO2 by up to 64.2%, HC by up to 80.4%, and PM by up to 23.5% with the MD11 blend. NOx emissions initially increased but decreased by up to 20% at higher torques with the same blend. These results highlight the environmental benefits of methanol–diesel blends and the need for effective NOx reduction strategies. [ABSTRACT FROM AUTHOR]

Abstract Abandoned coal mine goaf is affected by air leakages and prone to spontaneous combustion, resulting in environmental pollution and geological disasters. Haizhou Open-pit Mine adopts both underground and open-pit mining methods. During the long-term mining process, the original stable stratum structure is constantly destroyed, and the slope slides, increasing cracks and severe air leakage around the goaf and roadway. The spontaneous combustion of coal is particularly prominent after the mine shut down. At present, there is no suitable indirect monitoring method to effectively explore the spontaneous combustion area in goaf. The study developed an all-weather monitoring plan and conducted multi-point continuous long-term measurements of the spontaneous combustion state in one abandoned coal mine goaf located in the eastern part of the Haizhou Open-pit Mine. We evaluated the dynamic correlation between surface CO2 flux (SCF) and changes in the underground fire areas, determined the scope and evolution trend of the fire areas, and identified the distribution and change laws of SCF. The results show a significant positive correlation between SCF and soil temperature; moreover, the SCF value was found to reflect the CO2 emission intensity of the goaf. The high SCF in the test area showed month-wise expansion and increase, while the CO2 emission gradually increased monthly, and the calculated annual total emission was approximately 7017 t. Hence, the study can further provide guidance for the monitoring of spontaneous combustion in shallow coal seams, goaf and the assessment of CO2 emissions from underground coal fires through the on-site monitoring and analysis results.

Aiming at the difficult problem of gas drainage in low permeability outburst coal seam in China, taking the transportation lane of coal mining face in K15 coal seam of Maizigou Coal Mine in Guizhou Province as the engineering background, through the establishing the multi-field coupling model of gas flow in coal mining face under high temperature field, the gas drainage effect of coal seam boreholes under different heating temperature, borehole diameter and borehole spacing conditions was simulated and studied. The research shows that temperature has a significant impact on the effect of coal seam gas emission. When the heating temperature is 86 ℃, the gas pressure decreases significantly; the borehole diameter has a great influence on the effect of coal seam gas emission. When the borehole diameter is 113 mm, the maximum gas pressure between boreholes is 0.36 MPa, the maximum gas pressure decreases by 14.28% year on year, and the gas emission from boreholes increases by 27.27%. The effect of borehole spacing on coal seam gas pressure and discharge effect is also very obvious. When the borehole spacing is 1 m, the maximum gas pressure between boreholes is 0.45 MPa, and the influence range is 5.72 m. The decrease range of gas pressure increased by 37.8% compared with the hole spacing of 1.5 m and the influence range increased by 18.18% compared with the hole spacing of 1.5 m. The comprehensive gas discharge effect was the best. Comparing the simulation results of different schemes, the numerical simulation scheme 9 has the best gas emission effect.

The situation of coal mine safety production is still quite severe. Most coal mine accidents are caused by gas or coal dust explosion. Therefore, the monitoring and control of underground gas and coal dust is the key link to realize coal mine safety production. In this paper, through the data acquisition, processing and calculation of the monitored values, the corresponding optimization model and the optimization calculation formula of absolute gas emission and relative gas emission are obtained. Through the given data, the absolute gas emission and relative gas emission of each monitoring point in the coal mine are calculated every day. The absolute gas emission and relative gas emission of the total return air roadway are used to identify whether the mine belongs to "low" or "high" gas mine. Considering the possibility of gas explosion and coal dust explosion, the deviation degree between coal dust and the lower explosion limit of coal dust under the influence of gas concentration is cited to measure. The table shows the unsafe degree corresponding to different gas concentration and coal dust concentration. Through the diversion of air volume in each shaft and roadway, it is determined that the best total ventilation volume is the sum of the air volume of inlet roadway I and II and the roadway where the local fan is located (including the air volume of the local fan).Under the simplified assumption, the model is evaluated, popularized and improved through error analysis. [ABSTRACT FROM AUTHOR]

In order to reduce odor emissions and surface water pollution while storing manure in field heaps near a barn, there is a challenge in properly designing manure-storage areas. Therefore, it is important to assess what solutions and conditions, considering environmental requirements, should be considered when storing manure in field heaps. The goal of the research is to determine the impact of various factors on the risk of nutrient leaching, soil, and gas emissions from solid manure heaps, considering climatic factors in the environment. Through various scientific studies, a manure pile model has been developed and evaluated for its impact on the risk of potential leaching and odor emissions (using hyperspectral gas emission analysis mass flow method) from manure and the dynamics of the 0–80 cm soil layer properties (nitrate (N-NO3) and nitrite (N-NO2), ammonia (NH3), mineral, and total N). Based on the research results, requirements for manure management and storage during the prohibited fertilization period were established, considering the requirements for nitrates from agricultural sources in Lithuania. An optimal new manure heap model has been identified—a layer of not less than 20 cm of compacted straw (density 150–200 kg m−3) or a 10 cm layer of peat for absorbing manure slurries is formed on the soil surface, the manure heap is surrounded by an earth embankment not less than 30 cm high, the manure heap is covered with a layer of finely chopped straw not less than 10 cm thick, or 5 cm of sawdust, or 5 cm of peat. The manure is stored in the heap for 6–12 months. Following the research results, requirements for manure management and storage during the prohibited fertilization period were established, considering the requirements for nitrates from agricultural sources in Lithuania, applicable to the northern part of the temperate climate zone and applying similar requirements to the relevant countries. [ABSTRACT FROM AUTHOR]

This study examinedthe effect of Greenhouse Gas emission (GHGD) and energy consumption disclosure (ECDI) on the market competitiveness of listed non-financial firms on the Nigerian Exchange Group (NGX). Market competitiveness was proxied using the market-to-book ratio (MTBR). The study anchored on two theories: 'agency theory' and 'stakeholder theory'. The expost facto research design was used and a purposive sample of thirty-eight non-financial firms listed on the NGX during the study period were selected as the sample. This study utilised secondary sources of data, from annual financial statements retrieved from the MachameRatios® database. The data were analysed using multiple regression techniques. The results showed a significant negative effect of the GHGD on MTBR (p=0.0164); while ECDI had a non-significant positive on the MTBR (p=0.1140) of listed non-financial firms. The study concludes that GHG emissions and energy consumption disclosure affect the market competitiveness of listed non-financial firms in Nigeria. The study recommends that management and boards of non-financial firms should strive for increased transparency and disclosure of Greenhouse Gas emissions by companies. Companies can enhance their reputation among environmentally conscious investors by disclosing their GHG emissions, demonstrating their commitment to sustainability and climate responsibility. The management of non-financial firms should improve the energy consumption disclosure of their activities. Companies can enhance investor trust and confidence by disclosing their energy consumption levels and providing valuable information about their operational efficiency and resource management practices. [ABSTRACT FROM AUTHOR]

Seismic signals generated by mud volcanoes could be used to monitor gas emission. To this end, a seismic array of vertical geophones and three-directional velocimeters have been deployed close to major emission cones in the Nirano mud volcano area, in the northern Apennines. A detailed analysis of the resulting time series has been performed both in time and spectral domains, revealing the existence of three distinct kinds of signals: background noise, paroxysmal phases (drumbeats), and regular sequences of identical pulses (drumrolls). Both drumbeats and drumrolls are characterised by higher frequencies than the background seismic noise. Drumbeats show relatively high amplitudes and long durations (in the order of several seconds) but an irregular time pattern, while drumrolls are constituted by very regular sequences of almost identical short (less than 1 s) monochromatic pulses. Both drumbeats and drumrolls appear to be constituted by S waves, originated locally in the same shallow subsoil area, close to the main vents. These seismic signals could be related to the mechanical interaction of shallow solid conduits with a two-phase (mud and gas) slug flow from depth, which is characterised by irregularly spaced long bubbles (drumbeats), alternated with trains of small bubbles (drumrolls). [ABSTRACT FROM AUTHOR]

This work presents a model for solving the Economic-Environmental Dispatch (EED) challenge, which addresses the integration of thermal, renewable energy schemes, and natural gas (NG) units, that consider both toxin emission and fuel costs as its primary objectives. Three cases are examined using the IEEE 30-bus system, where thermal units (TUs) are replaced with NGs to minimize toxin emissions and fuel costs. The system constraints include equality and inequality conditions. A detailed modeling of NGs is performed, which also incorporates the pressure pipelines and the flow velocity of gas as procedure limitations. To obtain Pareto optimal solutions for fuel costs and emissions, three optimization algorithms, namely Fractional-Order Fish Migration Optimization (FOFMO), Coati Optimization Algorithm (COA), and Non-Dominated Sorting Genetic Algorithm (NSGA-II) are employed. Three cases are investigated to validate the effectiveness of the proposed model when applied to the IEEE 30-bus system with the integration of renewable energy sources (RESs) and natural gas units. The results from Case III, where NGs are installed in place of two thermal units (TUs), demonstrate that the economic dispatching approach presented in this study significantly reduces emission levels to 0.4232 t/h and achieves a lower fuel cost of 796.478 USD/MWh. Furthermore, the findings indicate that FOFMO outperforms COA and NSGA-II in effectively addressing the EED problem. [ABSTRACT FROM AUTHOR]

Active fault zones are critical pathways for the migration of deep fluids to the Earth’s surface, carrying gases such as He, Rn, and CO2 that provide evidence for the physical and chemical dynamics of the Earth’s interior. This review examines the geochemical characteristics of fault zone gases and their implications for understanding fault activity and seismic events. Fault zones with high activity levels exhibit significant gas release, and variations in soil and hot spring gas concentrations can serve as indicators of seismic activity. Changes in gas concentrations and isotopic ratios, particularly before and after earthquakes, reflect the dynamic interplay between deep-sourced and shallow-sourced fluids. Seismic-induced stress alterations enhance gas release along fault zones, leading to observable anomalies that can aid in earthquake monitoring and prediction. The study underscores the importance of isotope tracing in deciphering fluid sources, migration pathways, and the evolution of fault zones, providing valuable information for assessing tectonic activity and mitigating seismic risks.

This study examines the effects of methanol–diesel blends on the emissions of a diesel engine, concentrating on carbon monoxide (CO), carbon dioxide (CO2), nitrogen oxides (NOx), hydrocarbons (HCs), and particulate matter (PM). Using a single-cylinder four-stroke diesel engine at varying torque settings (2 N m–6 N m), significant reductions in CO, CO2, HC, and PM emissions were observed with increasing methanol content. CO emissions reduced by up to 81.8%, CO2 by up to 64.2%, HC by up to 80.4%, and PM by up to 23.5% with the MD11 blend. NOx emissions initially increased but decreased by up to 20% at higher torques with the same blend. These results highlight the environmental benefits of methanol–diesel blends and the need for effective NOx reduction strategies.

The increase in human population in the world is proportional to the increase in energy needs. Energy needs are still dominated by fossil energy. Efforts to reduce dependence on fossil energy are by using natural reserves from abundant energy sources, namely biomass. Utilization of candlenut shells and corn cob waste which are abundant in the West Nusa Tenggara (NTB) area can be used as mixed materials for making charcoal briquettes. The target of this research is to analyse the quality of a mixture of charcoal briquettes from a mixture of candlenut shells and corn cobs as an alternative future fuel. In the process of this research, variations of the mixture of candlenut shells and cobs were carried out with variable composition 1 (65% candlenut husk; 25% corn cob; 10% adhesive; variable 2 (55% candlenut husk; 35% corn cob; 10% adhesive); and variable 3 (45% candlenut husk; 45% corn cob; 10% adhesive). In this test, the calorific value, combustion rate, and emission gas test were calculated. The results showed that the mixture was 65% candlenut husk, 25% corn cob, and 10% adhesive. has the highest heating value of 5010 joules, which is according to SNI at least 5000 joules, the combustion rate is 0.91 g/m, and exhaust emissions are CO (1.18), CO2 (2.92), O2 (20.9) and HC (395) has met Indonesian national standards according to Minister of Environment Regulation Number 05 of 2006 concerning Emission Standards.

This article reviewed the research progress of several physical and chemical methods that can reduce the emission of fumigation gases during soil fumigation to prevent soil-borne harmful organisms, such as covering plastic films, increasing application depth, increasing soil moisture content, increasing soil bulk density, adding biochar, using drip irrigation systems, developing new fumigant formulations, and adding organic and inorganic fertilizers to the soil surface. Although using the above single method can reduce the emission loss of fumigation gas to varying degrees, combining the above technologies can achieve more ideal emission reduction effects. At the same time, it is recommended that relevant government management departments, researchers, and growers work together to promote the practical application of alternative emission reduction technologies besides plastic films covering. This effort aims to the use of plastic films while achieving a reduction in fumigation gas emissions, thereby minimizing the adverse impacts on the ecological environment. [ABSTRACT FROM AUTHOR]

The present study evaluated the effects of Quillaja saponin (QS) supplementation on growth efficiency, nutritional digestibility, gas emissions, and faecal score in growing pigs. In a 42-day experiment, 80 growing pigs [(Yorkshire × Landrace) × Duroc] were randomly assigned (29.17 ± 0.23 kg initial average body weight) to 2 different trial groups. Each group had 8 replicates, consisting of 3 male and 2 female pigs in each pen. The nutritional treatments included a control group (CON) receiving a basal diet and a treatment group (TRT1) receiving a basal diet supplemented with 0.01% QS. The results of this study indicated that pigs consuming the QS-supplemented diet exhibited significantly higher (P < 0.05) body weight on day 42 compared to the CON group. Furthermore, dietary QS led to higher (P < 0.05) average daily gain and showed a tendency to reduce (P < 0.10) the feed conversion ratio throughout the study period, as compared to the CON diet. Growing pigs that consumed the QS-supplemented diet also showed higher (P < 0.05) nutrient utilisation of dry matter and nitrogen compared to the CON group. At day 42, QS supplementation reduced (P < 0.05) NH3 and H2S emissions, along with a trend to reduce (P < 0.10) CH4 generation in the initial stage in comparison to the CON diet. Furthermore, the faecal score in the experimental group was lower (P < 0.05) on day 42 compared to control animals. In conclusion, QS proved to be a suitable supplement for growing pigs as it improved growth efficiency and nutrient digestibility, as well as reduced gas emissions and faecal score. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the dietary effects of Quillaja saponin (QS) and seaweed (SW) on growth performance, fecal score, and gas emissions in weaning pigs. A total of 120, 21-day old crossbred ([Yorkshire�×�Landrace] × Duroc) weaning pigs were randomly assigned to three treatment groups. These dietary treatments consisted of (1) TRT1: CON (basal diet), (2) TRT2: CON + 200�mg/kg QS, and (3) TRT3: CON + 500�mg/kg SW. Pigs were raised in 10 replicate pens per treatment (two males per pen and two females per pen) for 5 weeks based on body weight and sex. The inclusion of QS significantly (p�<�0.05) increased average daily gain (ADG) and average daily feed intake (ADFI) during the overall period compared to the control diet. Moreover, the tendency to increase ADG was found at weeks 1 and 5, whereas ADFI showed a tendency to increase at week 1 with the supplementation of QS compared to the CON diet. However, the feed conversion ratio, fecal score, and gas emission failed to show significant effects throughout the experiment. In summary, QS has a beneficial effect on the growth performance of weaning pigs without any negative effect on gas emission and fecal score. [ABSTRACT FROM AUTHOR]

A total of 180 growing pigs (Duroc × Landrace × Yorkshire) with an initial body weight (BW) of 23.58 ± 0.8 kg were used in this experiment. According to initial BW and sex, pigs were randomly allotted three dietary treatments, 12 replicates (pen) per treatment, and five pigs per pen. The three dietary treatments were basal diet (CON) and basal diet supplemented with either 0.1% Bacillus and Saccharomyces spp.-based probiotics complex (BS1) or 0.2% probiotics complex (BS2). The whole experiment lasted 42 days. The results showed that the BW of pigs fed the BS1 diet was significantly higher than those fed the CON diet on day 42 (P < 0.05). The average daily gain (ADG) of pigs receiving BS1 and BS2 diets was higher than those fed CON diet during days 21–42, whereas during the overall experiment period ADG (P < 0.05) was higher in only BS1 compared with CON group. The NH3 and H2S emissions on day 42 were reduced from the feces of pigs fed probiotic complex-supplemented diets. Therefore, adding 0.1% probiotic complex to the late-phase diet of growing pigs can more effectively improve BW and daily gain and reduce harmful gas emissions. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Inorganic Analytical Chemistry / Zhongguo Wuji Fenxi Huaxue is the property of Beijing Research Institute of Mining & Metallurgy Technology Group and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Traditionally, single‐beam echo sounder (SBES) data are used to determine the position of emission structures in the form of a two‐dimensional profile, which may not be straightforward enough to correlate the data of adjacent profiles and determine the exact discharge area. In this study, we develop semiautomatic software to remove noise and select possible flare signals to enhance the speed and precision of the data processing. The program also allows for the transformation of the data into a three‐dimensional point cloud distribution by computing the receiving angle of the data. By applying this method to investigate the distribution and mechanism of gas emission structures in the South Okinawa Trough (SOT), we determine four high flux areas and 22 isolated plumes with roots. Widespread gas flares usually occur in areas with large‐scale volcanic activity or gas‐enriched structures. Isolated gas plumes could be found for a single knoll outcrop and normal faulting structures. The energy of the flares around the knoll area is generally stronger than that observed along the normal faults. Compared with other geophysical data, we find that the widespread distribution of gas flares generally implies a larger hydrothermal potential, which may not be revealed by single‐profile acoustic image observations. We also find that the direction of flares is strongly influenced by tides, and the height of the flare represents the thermocline as a strong boundary for bubbles composited by carbon dioxide. Plain Language Summary: This study introduces a new method using SBES data to analyze gas emission structures in the South Okinawa Trough. By developing specialized software, the researchers enhance the speed and precision of data processing, allowing for the identification of high flux areas and isolated plumes. The study reveals that widespread gas flares indicate significant hydrothermal potential, influenced by tides and thermocline height. This research expands our understanding of gas emissions in the region. Key Points: The precise range and magnitude of gas discharges in the southern Okinawa Trough are determined by processing the SBES dataThe magnitude and intensity of gas discharges can be attributed to volcanic fluid activity or structural faultsThe three‐dimensional flares observed in the water column illustrate the impact of tides on the upward movement of gas plumes [ABSTRACT FROM AUTHOR]

Currently, research on neural network-based gas emission prediction models mainly focuses on the performance of gas emission problems, with less attention and improvement on the optimizer properties in model training. The training of gas emission prediction models based on neural networks often uses the Adam algorithm. But the non-convergence of the Adam algorithm can easily lead to the loss of the best hyperparameters of the prediction model, resulting in poor prediction performance. In order to solve the above problems, the Adam optimizer is improved by introducing a moment estimation parameter that updates iteratively in the Adam algorithm, achieving stronger convergence while ensuring convergence rate. Taking a certain mining face of Malan Mine in Xishan Coal and Power Group of Shanxi Coking Coal as an example, the training efficiency, model convergence, and prediction accuracy of the improved Adam optimizer in gas emission prediction are tested under the same recurrent neural network （RNN） prediction model. The test results show the following points. ① When the number of hidden layers is 2 and 3, the improved Adam algorithm reduces the running time by 18.83 and seconds 13.72 seconds respectively compared to the Adam algorithm. When the number of hidden layers is 2, the Adam algorithm reaches its maximum iteration number but still does not converge, while the improved Adam algorithm achieves convergence. ② Under different numbers of hidden layer nodes, the Adam algorithm does not converge within the maximum iteration step, while the improved Adam algorithm achieves convergence. The CPU running time is reduced by 16.17, 188.83 and 22.15 seconds respectively compared to the Adam algorithm. The improved Adam algorithm has higher accuracy in predicting trends. ③ When using the tanh function, the improved Adam algorithm reduces the running time by 22.15 seconds and 41.03 seconds respectively compared to the Adam algorithm. When using the ReLU function, the running time of the improved Adam algorithm and the Adam algorithm is not significantly different. ④ Using the improved Adam algorithm for traversal grid search, the optimal model hyperparameters are obtained as {3,20, tanh}, with mean square error, normalized mean square error, and running time of 0.078 5, 0.000 101, and 32.59 seconds, respectively. The optimal model given by the improved Adam's algorithm correctly judges the trends of several valleys and peaks that occur within the predicted range. The fitting degree on the training set is appropriate, and there is no obvious overfitting phenomenon.

Abstract The number of mines using roof cutting and pressure relief technology to extract mine deep coal resources is increasing daily. Most of these mines are facing the risk of high gas emission and residual coal spontaneous combustion disasters, and the composite disasters caused by these two risks also threaten the safety of mine production. On the basis of constructing a model for the evolution of porosity and permeability in a single side roof cutting along the gob, this study studied the occurrence locations of gas explosion risk areas, oxidation and heating risk areas, and composite disaster areas under different air supply and gas emission conditions, and summarized the evolution laws of composite disaster risk areas. The research results show that the roof rock collapse caused by roof cutting and pressure relief technology reduces the permeability of porous medium, which significantly reduces the sensitivity of the width of the oxidation temperature rise zone and the composite disaster area to the air supply. The increase in air supply causes the position of the composite disaster risk zone inside the goaf to shift toward the deep part of the goaf, while the width remains basically unchanged. The increase in gas emissions has suppressed the occurrence of coal spontaneous combustion in the goaf, while also keeping the gas concentration in a large area outside the upper limit of gas explosion. The research content enriches the research system of gas and oxygen flow fields in the goaf cutting face, and has positive significance for the promotion and application of goaf cutting technology and the understanding of secondary disasters caused by it.

Significant amounts of gases are emitted from the earth's crust into the atmosphere before, during, and after major earthquakes. To understand the relationship between gas emissions, earthquakes, and tectonics, we conducted a thorough investigation using satellite data from AQUA AIRS. We focused on three major earthquakes: the 12 May 2008 Wenchuan MW 7.9 earthquake in China's intra-continental plate, the 26 December 2004 Sumatra-Andaman MW 9.1 earthquake in Indonesia Island, and the 4 April 2010 Baja California MW 7.2 earthquake in Mexico's active plate margin. Anomalies in the total column (TotCO) and multiple layers (CO VMR) of carbon monoxide were observed along fault zones, with peak values at the epicenter areas. Furthermore, temporal anomalies of TotCO and CO VMR appeared in the month of the Wenchuan earthquake in the intra-continent, three months prior to the Sumatra-Andaman earthquake and one month before the Baja California earthquake in the active plate margins, respectively. Notably, the duration of CO anomalies before earthquakes in active plate margins was longer than that in the intra-continental region, and the intensity of the CO anomaly in active plate margins was higher than that in the intra-continental region. The results show a profound correlation with both seismic and tectonic activities, which was particularly evident in the earthquake's magnitude, rupture length, and the tectonic settings surrounding the epicenter. Furthermore, the type of the fault at which the earthquake occurred also played an important role in these CO anomaly variations. These findings support the identification of earthquake precursors and may help improve our understanding of earthquake forecasting and tectonics. [ABSTRACT FROM AUTHOR]

A major aim in the study of crustal fluids is the development of automatic methodologies for monitoring deep‐source, non‐volcanic gas emissions' spatio‐temporal evolution. Crustal fluids play a significant role in the generation of large earthquakes and the characterization of their emissions on the surface can be essential for better understanding crustal processes generating earthquakes. We investigate seismic tremors recorded over 4 days in 2019 at the Mefite d'Ansanto (southern Apennines, Italy) that is located at the northern end of the fault system that generated the Mw 6.9 1980 Irpinia Earthquake. The Mefite d'Ansanto is hypothesized to be the largest natural, non‐volcanic, CO2‐rich gas emission on Earth. The seismic tremor is studied by employing a dense temporary seismic network and an automated detection algorithm based on non‐parametric statistics of the recorded signal amplitudes. We extracted signal characteristics (RMS amplitude and statistical moments of amplitudes both in time and frequency domains) for use in the subsequent supervised machine‐learning classification of the target tremor and accidently detected anthropogenic and background noise. The data set is used for the training and optimization of station‐based KNN (k‐Nearest‐Neighbors) binary classifiers obtaining good classification performances with a median overall accuracy across all stations of 92.8%. The classified tremor displayed common features at all stations: variable duration (16 s to 30–40 min), broad peak frequency (4–20 Hz) with varying amplitudes, and two types of signals: (a) long‐duration, high‐amplitude tremor and (b) pulsating tremor. Higher tremor amplitudes recorded at stations closer to local bubbling and pressurized vents suggest multiple local tremor sources. Key Points: A dense temporary seismic array enabled the acquisition of emission‐related seismic tremor at the Mefite d'Ansanto siteA detection algorithm and supervised machine‐learning approach for the identification and classification of tremors has been developedNew insights on the emission tremor would help to monitor the CO2 degassing at the Mefite d'Ansanto and its temporal evolution [ABSTRACT FROM AUTHOR]

Poultry farmers constantly source for alternative feed additives for feeding poultry birds to improve the quality and health benefits of their meat and egg. It is common knowledge that synthetic feed additives (antibiotic growth promoters) are accompanied by some limitations. These limitations include amongst others, the detrimental residual effects accompanying the consumption of the meat and egg products of poultry birds fed antibiotic growth promoters. Also, they cause resistance to some bacteria both in poultry and humans. Recently, increased efforts have been put into utilizing plant-based feed additives in the nutrition of poultry birds, due to their minimal toxicity concerns and holistic functional attributes. Pomegranate is an important fruit that cannot be overlooked among the spectrum of natural feed additives. The potential of pomegranate fruit peel to replace in-feed antibiotic growth promoters in poultry nutrition is quite promising. The current review provides an overview of the usefulness and potential utilization of pomegranate peel as a natural and alternative growth promoter in the nutrition of poultry birds. The pomegranate fruit peel promotes growth, stimulates immune responses, enhances the shelf-life of meat, improves egg quality, increases nutrient release. It also improves bone quality, and ensures the release of odorous gases from poultry manure, which may be linked to its rich antioxidant and bioactive phenol and tannin constituents. Tannin is one of the anti-nutrients that limits the performance of poultry when it is included in the diet. Despite huge benefits of pomegranate inclusion in poultry performance, its tannin content may be a source of worry and these concerns needs to be addressed through further research in order to maximize the full potentials of pomegranate. However, pomegranate shows potential to provide nourishment to poultry birds and positively enhance the health indicators of human consumers of the products (meat and egg). [ABSTRACT FROM AUTHOR]

In order to improve the prediction ability of gas emission in mining face, a prediction model based on gate recurrent unit (GRU) is proposed to predict the gas emission by using the relevant influencing factors of gas emission. The initialization process of the sparrow search algorithm is improved, and the improved sparrow algorithm is used to optimize the hyper parameters affecting the GRU prediction model, so as to improve the prediction accuracy of gas emission. Combined with the adaptive enhancement ability of AdaBoost algorithm, an adaptive enhanced optimization gas emission prediction model ( ISSA-GRU-AdaBoost model ) is constructed, and the prediction index features are extracted by using principal component analysis to improve the rapidity of prediction. The model is compared with PSO-ELM model, QPSO-LSTM model, PSO-BP model and SSA-SVM model. The results show that the prediction accuracy of ISSA-GRU-AdaBoost prediction model is higher. [ABSTRACT FROM AUTHOR]

The number of mines using roof cutting and pressure relief technology to extract mine deep coal resources is increasing daily. Most of these mines are facing the risk of high gas emission and residual coal spontaneous combustion disasters, and the composite disasters caused by these two risks also threaten the safety of mine production. On the basis of constructing a model for the evolution of porosity and permeability in a single side roof cutting along the gob, this study studied the occurrence locations of gas explosion risk areas, oxidation and heating risk areas, and composite disaster areas under different air supply and gas emission conditions, and summarized the evolution laws of composite disaster risk areas. The research results show that the roof rock collapse caused by roof cutting and pressure relief technology reduces the permeability of porous medium, which significantly reduces the sensitivity of the width of the oxidation temperature rise zone and the composite disaster area to the air supply. The increase in air supply causes the position of the composite disaster risk zone inside the goaf to shift toward the deep part of the goaf, while the width remains basically unchanged. The increase in gas emissions has suppressed the occurrence of coal spontaneous combustion in the goaf, while also keeping the gas concentration in a large area outside the upper limit of gas explosion. The research content enriches the research system of gas and oxygen flow fields in the goaf cutting face, and has positive significance for the promotion and application of goaf cutting technology and the understanding of secondary disasters caused by it. [ABSTRACT FROM AUTHOR]

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Abstract The gas pressure in front area of heading face is essential to dynamically evaluate coal and gas outburst during coal mining. In this work, a novel inversion model of gas pressure in front area of the heading face was established on premise of the hypothesis that a time-dependent zone of steady flow exists within newly exposed face. The key parameters in the inversion model were obtained based on the gas emission models and field data of gas emission rate in different times, which were used to calculate the volumes of gas emission from different sources. The results show that the percentage of gas emission from the heading face, coal wall and collapsed coal ranges from 7% to 47%, 47% to 82% and 2% to 11%, respectively. Based on the calculated volumes of gas emission and gas pressure inversion model, the gas pressure was obtained and transformed to the gas content. The absolute errors between the gas content tested and transformed in every hour is 0.4%–33%, which proved the rationality of gas pressure inversion model. Furthermore, the daily drifting footage, the radius of gas pressure boundary and the gas permeability coefficient of coal seam were confirmed to have a great effect on the result of gas pressure inversion. The inversion results verify that the speedy excavation can increase the risk of coal and gas outburst. This work produces a useful method for gas disaster prevention and control that converts the gas emission rate to an index of gas pressure within coal seam.

As the disaster-causing characteristics of coal and gas outburst and the mechanism of induced mine airflow disaster are not clear, the facilities such as air door and self-rescue system are often arranged on site according to miner’s experience, thus it is difficult to take safety protection measures and formulate scientific and reasonable emergency plan. In order to accurately grasp the impact dynamic effect and disaster-causing characteristics of coal and gas outburst, based on the similarity theory, a set of physical simulation experimental system considering the disaster-causing strengthening effect caused by gas in the pressure relief area around the outburst hole was developed. And the key parameters of the gas supplement device were determined through strict calculation based on the outburst model and gas seepage theory. The experimental system mainly includes outburst hole dynamic system, outburst excitation device, roadway simulation system and data acquisition and control center, which can simulate outburst dynamic phenomena such as the formation and propagation of outburst shock wave, the migration of outburst coal-gas two-phase flow and gas countercurrent in the simulated roadway. The simulation experiment of outburst disaster with a gas pressure of 0.8 MPa was carried out. And the forming process of outburst shock wave was directly observed with a high-speed camera. The results show that the outburst shock wave is formed instantly in the pipeline at the moment of outburst, followed by impact flow, outburst gas flow and coal-gas two-phase flow. The comparable velocities of each parameter are in the order: the air shock wave velocity > impact flow velocity > outburst gas-flow velocity > outburst coal-gas two-phase flow front velocity. The maximum velocities of each parameter are 546.5, 496.7, 112.6 and 51.5 m/s respectively, and gradually decay along the pipeline. At the moment of outburst, high-pressure gas poured into the roadway space from the outburst hole, resulting in gas reflux. During the outburst process, the gas pressure inside the outburst hole decreases exponentially. After the outburst occurs, the gas concentration in the roadway changes with time in “sudden rise stage” and “slow decline stage”, and the migration mode of the gas outburst in the roadway mainly includes “displacement" and “diffusion”. The accumulation height and quality of outburst coal along the main roadway are consistent. The difference of grain size distribution between outburst coal and raw coal is mainly concentrated in 0−500 μm, while the difference of maximum grain size distribution is mainly concentrated in 150−200 μm. In addition, the proportion of coal powder with particle size distribution in the range of 150−200 μm increases with the increase of the distance from the outburst mouth, showing a strong sorting ability.

In order to reduce odor emissions and surface water pollution while storing manure in field heaps near a barn, there is a challenge in properly designing manure-storage areas. Therefore, it is important to assess what solutions and conditions, considering environmental requirements, should be considered when storing manure in field heaps. The goal of the research is to determine the impact of various factors on the risk of nutrient leaching, soil, and gas emissions from solid manure heaps, considering climatic factors in the environment. Through various scientific studies, a manure pile model has been developed and evaluated for its impact on the risk of potential leaching and odor emissions (using hyperspectral gas emission analysis mass flow method) from manure and the dynamics of the 0–80 cm soil layer properties (nitrate (N-NO3) and nitrite (N-NO2), ammonia (NH3), mineral, and total N). Based on the research results, requirements for manure management and storage during the prohibited fertilization period were established, considering the requirements for nitrates from agricultural sources in Lithuania. An optimal new manure heap model has been identified—a layer of not less than 20 cm of compacted straw (density 150–200 kg m−3) or a 10 cm layer of peat for absorbing manure slurries is formed on the soil surface, the manure heap is surrounded by an earth embankment not less than 30 cm high, the manure heap is covered with a layer of finely chopped straw not less than 10 cm thick, or 5 cm of sawdust, or 5 cm of peat. The manure is stored in the heap for 6–12 months. Following the research results, requirements for manure management and storage during the prohibited fertilization period were established, considering the requirements for nitrates from agricultural sources in Lithuania, applicable to the northern part of the temperate climate zone and applying similar requirements to the relevant countries.

This work presents a model for solving the Economic-Environmental Dispatch (EED) challenge, which addresses the integration of thermal, renewable energy schemes, and natural gas (NG) units, that consider both toxin emission and fuel costs as its primary objectives. Three cases are examined using the IEEE 30-bus system, where thermal units (TUs) are replaced with NGs to minimize toxin emissions and fuel costs. The system constraints include equality and inequality conditions. A detailed modeling of NGs is performed, which also incorporates the pressure pipelines and the flow velocity of gas as procedure limitations. To obtain Pareto optimal solutions for fuel costs and emissions, three optimization algorithms, namely Fractional-Order Fish Migration Optimization (FOFMO), Coati Optimization Algorithm (COA), and Non-Dominated Sorting Genetic Algorithm (NSGA-II) are employed. Three cases are investigated to validate the effectiveness of the proposed model when applied to the IEEE 30-bus system with the integration of renewable energy sources (RESs) and natural gas units. The results from Case III, where NGs are installed in place of two thermal units (TUs), demonstrate that the economic dispatching approach presented in this study significantly reduces emission levels to 0.4232 t/h and achieves a lower fuel cost of 796.478 USD/MWh. Furthermore, the findings indicate that FOFMO outperforms COA and NSGA-II in effectively addressing the EED problem.

Abstract Plant–biochar interaction has been recognized to affect the hydraulic properties of landfill cover soils, while its influence on landfill gas emission is rarely studied. This study investigated the coupled effects of biochar and vegetation on gas permeability and emission in unsaturated landfill cover through an integrated theoretical modelling and laboratory investigation. First, a gas permeability model was developed for vegetated coarse-grained soils with biochar addition. Then, a well-instrumented laboratory column test and two tests from the literature, considering bare, grass, biochar and grass + biochar conditions, were used for model validation. Finally, a numerical parametric study was conducted to investigate the influence of root growth and drought conditions on the gas emission rate. Results showed that the developed model can satisfactorily capture the gas permeability of unsaturated soils at various degrees of saturation. The lowest water retention capacity, the highest gas permeability and gas emission rate after 24 months of growth were observed in the grassed column. However, adding biochar in vegetated soils can maximize the water retention capacity and decrease the gas permeability, resulting in the lowest gas emission rate. The measured gas emission rates for the four cases meet the recommended value by the design guideline. The parametric study showed that the increased root depth from 0.2 m to 0.4 m improved the gas emission rate by 170% in the grass case but decreased by 97% in the grass + biochar case. Under the severe drought condition with soil suction around 500 kPa, the gas emission rate in the grassed case exceeded the design value by 18%, while those in the biochar cases were far below the allowable value. Therefore, peanut shell biochar should be considered to amend the grassed landfill cover using coarse-grained soils as it can significantly improve engineering performance in reducing gas emissions under extreme drought conditions. Graphical abstract

Abstract A major aim in the study of crustal fluids is the development of automatic methodologies for monitoring deep‐source, non‐volcanic gas emissions’ spatio‐temporal evolution. Crustal fluids play a significant role in the generation of large earthquakes and the characterization of their emissions on the surface can be essential for better understanding crustal processes generating earthquakes. We investigate seismic tremors recorded over 4 days in 2019 at the Mefite d’Ansanto (southern Apennines, Italy) that is located at the northern end of the fault system that generated the Mw 6.9 1980 Irpinia Earthquake. The Mefite d’Ansanto is hypothesized to be the largest natural, non‐volcanic, CO2‐rich gas emission on Earth. The seismic tremor is studied by employing a dense temporary seismic network and an automated detection algorithm based on non‐parametric statistics of the recorded signal amplitudes. We extracted signal characteristics (RMS amplitude and statistical moments of amplitudes both in time and frequency domains) for use in the subsequent supervised machine‐learning classification of the target tremor and accidently detected anthropogenic and background noise. The data set is used for the training and optimization of station‐based KNN (k‐Nearest‐Neighbors) binary classifiers obtaining good classification performances with a median overall accuracy across all stations of 92.8%. The classified tremor displayed common features at all stations: variable duration (16 s to 30–40 min), broad peak frequency (4–20 Hz) with varying amplitudes, and two types of signals: (a) long‐duration, high‐amplitude tremor and (b) pulsating tremor. Higher tremor amplitudes recorded at stations closer to local bubbling and pressurized vents suggest multiple local tremor sources.

This paper provides an experimental investigation of a Kerosene/air flame (produced by the NexGen burner designed by the FAA, and here calibrated for ISO 2685/AC20-135 standards fire tests conditions), which is used to generate flame/burnt gases impinging on material samples in the field of fire safety. The purpose of this study is to characterize this burner, and experimental means are implemented to better understand the effects of the equivalence ratio on the spatial distribution of the gas temperature (thermocouples) and the heat flux (heat flux gauge). A parametric study was carried out by varying the global equivalence ratio (ER); highlighting a flickering phenomenon, a relation between the ER and the heat flux, and determining empirical correlations. Hence, the measured flame temperature, heat flux, and heat release rate increase up to a critical value of equivalence ratio equal to 1.03 (flame temperature (1101.5 °C) and heat flux (140 kW/m2).

The gas pressure in front area of heading face is essential to dynamically evaluate coal and gas outburst during coal mining. In this work, a novel inversion model of gas pressure in front area of the heading face was established on premise of the hypothesis that a time-dependent zone of steady flow exists within newly exposed face. The key parameters in the inversion model were obtained based on the gas emission models and field data of gas emission rate in different times, which were used to calculate the volumes of gas emission from different sources. The results show that the percentage of gas emission from the heading face, coal wall and collapsed coal ranges from 7% to 47%, 47% to 82% and 2% to 11%, respectively. Based on the calculated volumes of gas emission and gas pressure inversion model, the gas pressure was obtained and transformed to the gas content. The absolute errors between the gas content tested and transformed in every hour is 0.4%–33%, which proved the rationality of gas pressure inversion model. Furthermore, the daily drifting footage, the radius of gas pressure boundary and the gas permeability coefficient of coal seam were confirmed to have a great effect on the result of gas pressure inversion. The inversion results verify that the speedy excavation can increase the risk of coal and gas outburst. This work produces a useful method for gas disaster prevention and control that converts the gas emission rate to an index of gas pressure within coal seam. [ABSTRACT FROM AUTHOR]

Organic fireproof plugging material (OFPM) is commonly applied in buildings to prevent the spread of smoke and flame. Its pyrolysis characteristics, reaction mechanisms and gas emission were studied by thermogravimetric analysis coupled with Fourier infrared spectroscopy and mass spectrometry (TG-FTIR-MS). The thermogravimetric analysis showed that the pyrolysis process of OFPM in nitrogen might be divided into four stages, which could be attributed to the dehydrogenation of polychloroprene (PCP), depolymerization of PCP and decomposition of kaolinite and carbonate. The reaction mechanism of OFPM in nitrogen atmosphere was further investigated by various kinetic methods. The average activation energy of the four stages was 92.47, 166.47, 239.69 and 232.72 kJ mol−1. In addition, (g(a) = [1−(1–a)−3]/ (−3)) was responsible for Stage I, and (g(a) = [−ln(1–a)]2) was responsible for Stage IV. The characteristic parameters and kinetic triplets were verified by predicting the experimental data at an extra heating rate. The predicted conversion rate curve was consistent with the experimental conversion rate curve, which manifested the accuracy of the obtained parameters. In addition, the evolved gas consisted of ethane, HCl, 1, 3-butadiene, 2-chloro-1, 3-butadiene and CO2 by the FTIR-MS analysis. Eventually, the pyrolysis pathway was proposed based upon thermogravimetric and gas analysis results. [ABSTRACT FROM AUTHOR]

Due to the mismatch between gas production and consumption in the gas delivery system (GDS), reduced customer demand can easily lead to overpressure and gas release. Companies mainly use high-pressure release (HPR) to lower the GDS pressure, which results in significant energy losses for compression and gas separation. This paper (1) proposes a low-pressure release method (LPR) for users' low-demand scenarios to avoid regulating air separation units, and (2) provides a way for obtaining optimal parameters for LPR when used alone and together with HPR. LPR released low-pressure gas by lowing the compressor inlet guide vane opening (IGA) or the inlet valve opening to reduce the compressor load, outlet pressure, and GDS pressure, and reduce the energy consumption of the compressor. Case studies showed LPR reduced effectively the gas emissions and compressor operating energy. When LPR is used alone, the maximum reduction in gas emissions and compressor operating energy consumption compared with HPR was 6,049 Nm3 and 900 kW·h , accounting for 62.96% and 2.18%, respectively, and the gas emission rate was reduced from 0.11% to 0.04%. When LPR was used together with HPR, 43.88% oxygen emissions and 0.28% total compressor energy consumption were reduced, and the total conditioning time can be effectively reduced from 42 to 10 min. The method increases the ability of the compressor to regulate the GDS. [ABSTRACT FROM AUTHOR]

For decades, a significant amount of research has been conducted on the vitrification of mixtures of all kinds of industrial wastes, especially fly ash, both from thermal power plants and municipal waste incinerators. Although the possibility of creating glass from all types of fly ash has been proven through such research, these studies barely focused on the emission of volatile components that takes place during vitrification processes at high temperatures. This is why, after identifying the types of volatilisation that can occur, we characterised the gasses that are emitted during the vitrification of some types of fly ash and other waste in a laboratory furnace. In order to do so, we analysed the Cl2 and SO2 gasses emitted using the DTA/TG/FTIR techniques, as well as the losses of H2O and CO2. The authors also measured the volatilizations directly from the mouth of the furnace using gas chromatography syringes and analysed the possible emission of dioxins. This study is the first analysis of volatile elements of this kind, after numerous vitrifications in recent decades which ignored the volatilisations that occur when using fly ashes. Although the various types of fly ash used generate emissions of Cl2 and SO2, their use as a by-product on an industrial level could be recommended if previous thermal and washing treatments are conducted. These would minimise the above emissions, enabling the use of said fly ash in the production of glasses for commercial frits, even if an efficient industrial-scale gas cleaning system would apply. Furthermore, an appropriate optimised design of its formulation would make it possible to structurally link some of these gaseous components to the glass structure. These types of results will make it possible to calculate the volatilization when vitrifying certain types of industrial waste on an industrial level, although these studies would require prior assessment in a pilot plant. [ABSTRACT FROM AUTHOR]

Coalbed methane (CBM) is a clean energy source, but its utilization is inefficient due to the complexity and low accuracy of its emission prediction model. In this research, we constructed a mathematical model of gas emission from the excavation workface, and combined the experimental results to propose a new model for accurate and concise prediction. The new model was validated in the field workface and compared with the traditional prediction model. Moreover, the sensitivity of gas emission parameters and the participation ratio of gas emission sources were analyzed. The study results show that the new model has higher calculation accuracy than the old model prediction, with an average error reduction of 4.693%. In the excavation workface, the coal fall gas emission conforms to the negative power function equation, and the coal wall gas emission conforms to the negative exponential function equation. In the early stage of excavation, the proportion of coal fall gas emission is higher than that of coal wall gas emission, and the peak proportion reaches 58.5%. In the later stage, the proportion of coal fall gas emission gradually decreases to below 30%. The order of the sensitivity of gas emission parameters is coal wall gas initial velocity > coal fall gas decay coefficient > coal fall gas initial velocity > coal wall gas decay coefficient. The new model is successfully applied in engineering, which helps to improve the efficiency of coal mine gas disaster control and utilization. [ABSTRACT FROM AUTHOR]

Cr 2 AlC is one of the most interesting MAX phase compositions to operate under aggressive environments up to 1400 °C, but the effect of humidity at high temperatures is still poorly investigated. Cr 2 AlC high-temperature oxidation tests under controlled humidity are carried out on fined-grained samples for 40 h in the [1000–1400 °C] temperature range and compared to a previous study performed on single-crystals, fine and coarse-grained samples oxidized under dry air. Oxidation products are characterized and mass gain curves are analysed using both cubic and paralinear oxidation models to extract kinetics and characterize gas emission during the oxidation tests. These experimental data are supported by thermodynamic calculations in order to propose a quite complete oxidation mechanism for Cr 2 AlC. The nature and the arrangement of the oxidation products formed during wet and dry air oxidation tests are similar - a continuous Al 2 O 3 layer and a Cr 7 C 3 sublayer with pores- which demonstrates that the water vapor does not affect significantly the high-temperature oxidation of Cr 2 AlC. The acceleration of the oxidation process during wet air tests is correlated to the higher partial pressure of gaseous species produced in the presence of humidity which is associated with the chromium carbide's volatilization in the form of carbon oxide. [ABSTRACT FROM AUTHOR]

The thermal safety of lithium-ion traction batteries is a highly concerning issue in the field of electric transportation. The large amount of gas emissions during the thermal runaway process of batteries has high safety hazards, such as fire and explosion. The quantitative analysis of emissions is one of the important challenges in testing and evaluating battery safety. Focusing on quantifying gas emissions using large-scale thermal propagation in battery modules and packs, based on the idea of cell result multiplication, this article conducts a thermal runaway emission analysis of a single cell and a module and compares the behavior of thermal runaway and gas emissions of the cell and module from the perspectives of temperature, pressure, gas composition, and battery morphology. The feasibility of the cell result multiplication method is verified from the perspective of experimental data. [ABSTRACT FROM AUTHOR]

Broiler deep litter is composed of cellulose, manure, feathers, and feed, and after reuse through several flocks, may be used as a fertilizer. Alternative litter materials such as plastic flooring have been researched but little is known about the characteristics of the waste produced. We analyzed the properties of broiler manure from different flooring systems and assessed its potential for biodigestion. Broiler chicks (1500 one-day-old) were reared using five flooring materials: wood shavings (WS); plastic floor (PP); 50% shavings + 50% plastic floor (PP + WS); plastic floor with antimicrobial additive (PPA); and 50% shavings + 50% plastic floor with an antimicrobial additive (PPA + WS). Waste collection was done at 14, 28, and 42 days of growth. The total residue (kg) produced was quantified on day 42. The total solids (TS), volatile solids (VS), neutral detergent fiber (NDF), acid detergent fiber (ADF), nitrogen (N), and pH were analyzed at 14, 28, and 42 days of growth, using the residue coefficient (RC) on the 42nd day. The contents of ST, SV, NDF, ADF, C, and N were determined for anaerobic digestion. The concentrations of O2, CO2, and CH4 produced by anaerobic digestion were analyzed. The flooring material did not affect the volatile solids' contents. The lowest NDF and ADF were found in plastic floor residues. The pH of the manure linearly increased over time as the birds grew. The presence of wood shavings in the manure was decisive for the production of biogas. The treatments with the plastic floor without shavings obtained the highest N content with less residue. Plastic flooring with wood shaving is not recommended as it increases waste generation. The use of plastic flooring reduced the amounts of waste generated and promote a greater yield of biogas with the anaerobic digestion of excreta. [ABSTRACT FROM AUTHOR]

Due to its excellent effect of surface subsidence reduction, the overburden-separation grouting (OSG) technology has been widely applied to green mining. However, OSG changes the mine pressure, and the resultant gas emission in the stope remains unclear. Therefore, with the 22301 working face of Tunlan Coal Mine as an example, the overburden deformation and stress distribution in the absence and presence of OSG were studied through numerical simulation and on-site tests. Furthermore, the gas emission law in the stope was contrastingly analyzed. The following results were obtained. With the rise of grouting pressure (GP), the subsidence of strata above the separation layer decreases while that below the separation layer increases; the heave displacement of floor strata below the coal seam gradually decreases. OSG significantly changes the geometric shape and range of the overburden stress relief zone. As the GP rises, the gas enrichment area moves downward continuously and shrinks spatially. Horizontally, the ranges of the stress relief zone and the free space in the goaf shrink, while the range and compaction degree of the compaction area gradually grow. After OSG, the total amount of gas emission in the working face falls by 52.2%. [ABSTRACT FROM AUTHOR]

Exogenous protease has emerged as a promising solution for enhancing protein digestion and utilization in animal diets, offering potential benefits for both animal performance and environmental impact mitigation in pig farming. In a 6-wk trial involving 140 growing pigs [initial body weight (BW) = 24.10 ± 1.66 kg], the effects of dietary protease supplementation on growth performance, nutrient digestibility, and noxious gas emission were investigated. Pigs were randomly assigned to one of four dietary treatments in a 2 x 2 factorial design with two levels of nutrient density and 0 or 125 g/ton supplementation of protease. The pigs were blocked by BW and housed in 28 pens with each pen consisting of 5 pigs (3 barrows and 2 gilts). The experimental design employed a randomized complete block design with 7 replicate pens per treatment. The data were analyzed using two-way ANOVA, with differences between means assessed using Tukey’s test (P < 0.05). Results revealed no significant interaction (P > 0.05) between nutrient density and protease supplementation concerning growth performance, nutrient digestibility, and noxious gas emission. Pigs subjected to high-density diets exhibited greater (P < 0.05) average daily gain (ADG) and gain-to-feed ratio (G:F) compared with those on low-density diets. While protease supplementation did not impact ADG and average daily feed intake (ADFI), there was a tendency towards reduced (P = 0.08) G:F throughout the 6-wk period. Pigs fed high-density diets demonstrated significantly greater (P < 0.05) apparent total tract digestibility (ATTD) of gross energy (GE) compared with their counterparts on low-density diets. Furthermore, the inclusion of protease significantly increased (P < 0.05) ATTD of GE. However, no discernible differences were noted among diets regarding the ATTD of dry matter and nitrogen. Regarding noxious gas emission, protease supplementation did not significantly affect total mercaptans and hydrogen sulfide (H2 S) emission. Nonetheless, there was a notable trend towards reduced (P = 0.06) ammonia gas (NH3 ) emission with protease inclusion. Similarly, nutrient density did not exhibit a significant effect (P > 0.05) on noxious gas emission. In conclusion, the results of the study underscore the importance of nutrient density and protease supplementation in optimizing pig performance and environmental sustainability in swine production systems. Further research is warranted to elucidate the underlying mechanisms and refine strategies for maximizing the benefits of these dietary interventions. [ABSTRACT FROM AUTHOR]

Oat (Avena sativa L.) is one of the agricultural crops that can be grown in marginal areas. Grain and straw are used mainly for food and fodder purposes. However, due to the high-fat content in the grain and the small amount of ash, it can be an attractive raw material for energy production. The biomass can be straw and oat grain. Grain should be intended for food purposes, but if it does not meet the quality requirements, it can be used for energy purposes. The aim of the experiment was to evaluate the energy usefulness of four oat cultivars depending on the applied level of nitrogen fertilization. The research results show that oat grain and straw can be used as fuel for energy purposes. The average calorific value of grain was 18.7 MJ·kg−1, and the ash content in dry matter was 2.03%. With the increase in the dose of nitrogen fertilization, a decrease in the calorific value of oat and straw grains and a decrease in ash content were noted. The findings show significant varietal differences. Oat straw had a lower calorific value and a higher ash content, which indicates its lower usefulness for energy purposes compared to grain. [ABSTRACT FROM AUTHOR]

Nitrous oxide (laughing gas, N2O) is a relevant greenhouse gas. Agriculture contributes significantly to its emissions. As nitrogen fertilization has been identified as one of the main sources of N2O, controlled application and reduction of the amount of fertilizer adapted to crop demand is essential to reduce N2O emissions. This requires detailed studies of the local distribution of the N2O emission fluxes on different croplands. Consequently, frequent spatially resolved field measurements of N2O concentrations are needed. A precision in the ppb range close to the ambient N2O level of 333 ppb is necessary. Tunable laser absorption spectroscopy using quantum-cascade lasers (QCL) as a light source is an established technique for the measurement of N2O traces. We present the development and validation of a compact portable setup for on-site measurement of N2O emissions from the soil. The setup differs from previous solutions by using an interband cascade laser (ICL), which has significantly lower power consumption compared to a QCL. The portable measurement setup allows N2O emission fluxes to be determined with a precision of 3.5% with a measuring duration of 10 min. The developed system enables the detection of increased N2O emissions because of the fertilization of fields. High N2O emission fluxes are indicators of the overfertilization of the field. Directly after fertilization, N2O fluxes between 2.9 and 5.3 µL m−2 min−1 depending on the gas acquisition site are measured during the field tests. Over time, the fluxes decrease. The obtained results compare well with data from more precise but also more complex and maintenance-intensive instruments for atmospheric research. With this system, the soil moisture as well as the air humidity and air temperature are recorded. Strong influences on N2O fluxes by soil moisture were observed. The presented measurement system is a contribution to the establishment of mobile N2O screening systems that are robust in the field and suitable for comprehensive and routine detection of N2O emissions from soil. [ABSTRACT FROM AUTHOR]

The transport of water and gas is the most important process for the performance evaluation of landfill cover. However, the transport behaviors of these two components have been calculated separately (i.e., ignoring their coupling effect) in analytical solutions due to the complexity, although this coupling effect has been widely demonstrated in numerical studies, laboratory tests, and field tests. This study presents an analytical solution for coupled water–gas transport in a single-layer landfill cover, which can consider transient diffusive–advective transport of gas under steady-state water transport. The proposed analytical solution is verified against the field data, laboratory data, and numerical simulations. Parametric study is conducted to investigate the effects of four important parameters (i.e., infiltration rate, evaporation rate, desaturation coefficient, and saturated coefficient of water permeability) on the coupled water–gas transport behaviors, and the results indicate that these parameters all have a significant impact on the coupled water–gas transport (e.g., the gas emission flux for the case with desaturation coefficient α = 0.9 m–1 is 11.9 times greater than that with α = 0.3 m–1). For the simulations considered, ignoring the coupling effect would underestimate the steady-state gas emission flux by about 10.9– 54.2%, due to the changes of gas transport properties induced by water transport. The magnitude of this underestimation (i.e., error induced by ignoring the coupling effect) increases with decreasing infiltration rate, increasing evaporation rate, increasing desaturation coefficient, and decreasing saturated coefficient of water permeability. [ABSTRACT FROM AUTHOR]

In the search for precursors to earthquakes, correlation has been found between geochemical characteristics of soil gases and seismic activity. In this paper we present evidence that seismic waves can trigger emission of soil radon (Rn) and carbon dioxide (CO2). An active experiment was performed in two fault zones in China, the Annighe fault in Sichuan province and the Xiadian fault in Heibei province. An active seismic source was used to generate seismic waves at 10 m depth in wells within bedrock. Rn and CO2 detectors were placed around the wells at a distance of ∼1 m for observing the effects of the seismic waves on the emission of the gases. The observations confirm that the seismic waves have a significant and direct effect on the concentration and flux of soil radon and carbon dioxide. When the seismic events were triggered, the observed concentrations of Rn and CO2 immediately increased and reached peak values within 5–50 min and 30–60 min, with corresponding increases of Rn and CO2 concentrations by 10.5%–238.7% and 3.1%–54.1%, respectively. The measured concentrations and flux of CO2 and Rn after the passage of the seismic waves showed strong correlation, confirming the suggestion that CO2 is the carrier gas for Rn. To the best of our knowledge this is the first direct, in‐situ measurement of gas emission caused by the passage of seismic waves and provides important constraints for better understanding of geochemical earthquake precursors. Plain Language Summary: Observed geochemical properties of soil gases migrated from the deep Earth can be used to survey seismicity, volcanic activity and emission of greenhouse gases. However, due to difficulty in natural earthquake prediction, most observations on the geochemical effects linked to seismic activity are conducted after or away from naturally occurring events, with the effects normally inferred from seismic parameters. In this study, an active seismic source based on methane gaseous detonation was employed to artificially produce seismic events along two fault zones, and in‐situ measurements of concentrations and flux of radon (Rn) and carbon dioxide (CO2) were conducted. These observations showed strong correlation between concentrations and flux of CO2 and Rn after the events, in agreement with the hypothesis that CO2 is the carrier gas for Rn in tectonically active settings. Key Points: Soil CO2 and Rn emission triggered by a new type active source that excited at 10 m deep well in bedrock are observed at first timeQuantitative effect of seismicity on the concentration and flux of soil CO2 and Rn are presentedEmission of CO2 and Rn after the seismicity show strong correlation and proved that CO2 is the carrier gas for Rn [ABSTRACT FROM AUTHOR]