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In order to investigate particulate matter (PM) emission characteristics from the combustion of commercial biomass pellet, a fixed-bed reactor was used to conduct combustion experiments of wood dust, cotton stalk and bamboo dust. The particle size distributions and main element composition of PM were analyzed. And the influence of element content on PM emission was discussed. It was found that the yields of PM10 from high to low was cotton stalk, wood dust and bamboo dust, and the yields were 27. 76, 20. 83 and 9. 65 mg/ m3, respectively. The PMs were mainly composed of submicron particles (PM1 ), and the proportion of PM1 to PM10 was more than 90%. PM1 was mainly composed of alkali metal chloride and sulfide, while PM1-10 was mainly composed of compounds formed by calcium magnesium silicate. Correlation analysis showed that there was a positive correlated between biomass ash content and PM1 yield, while the content of Mg+Ca and n (Mg+Ca) / n (Si) were linearly correlated with PM1-10 yield. [ABSTRACT FROM AUTHOR]

Copyright of Precious Metals / Guijinshu is the property of Precious Metals Editorial Office 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.)

Copyright of Natural Gas & Oil is the property of Editorial Department of Natural Gas & Oil 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.)

ObjectiveTo improve the combustion, performance and emissions of high-power marine engines, diesel fuel micro-injection with methanol ignition is adopted to study the in-cylinder combustion and emission characteristics. MethodsA three-dimensional simulation model of a diesel micro-injection pilot-ignition methanol engine is established on the basis of an ACD320 high-power marine medium-speed diesel engine in order to study the effects of injector parameters (nozzle number and methanol spray angle γ) on the combustion performance and emission characteristics of a marine large-bore methanol engine.ResultsWith the increase in the number of nozzle, the in-cylinder methanol atomization improves and the in-cylinder work mass mixing becomes more adequate, leading to the advancement of CA50 and the shortening of the combustion duration. While this yields higher indicated thermal efficiency（ITE） and a better equivalent indicated specific fuel consumption (EISFC), as well as contributing to the reduction of soot emissions, it also causes the elevation of NOx emissions. Moreover, as the methanol spray angle increases, the ITE increases, obtaining better fuel economy and lower soot emissions. With the optimal methanol spray angle (γ = 60°), the methanol spray is located in front of the diesel spray injection point, the flame propagation speed in the cylinder is faster, the indicated thermal efficiency is at its maximum and the fuel combustion is fuller, thereby obtaining the lowest soot emissions and most optimal EISFC.ConclusionThe results of this analysis can provide a theoretical basis for engine injector parameters.

In order to obtain the influencing rule of secondary combustion on emissions and combustion oscillation characteristics of gas turbine axial staged combustor in non-premixed combustion mode and explore a load increasing mode with stable low emission, an axial staged combustor for F-class gas turbines is selected for experimental study. The results show that CO consumption is restrained and CO emission increases sharply when secondary fuel is added at a lower combustor outlet temperature. The addition of secondary fuel and the increase of secondary equivalence ratio lead to the reduction of NOx emission, but the increase of load can weaken the ability of secondary fuel to reduce NOx emission. The addition of secondary fuel and the increase of secondary equivalence ratio restrain the combustion oscillation in the low frequency band (75—90 Hz). When the secondary equivalence ratio is higher than a certain threshold (0.19), the addition of secondary fuel can restrain higher frequency(175—210 Hz) combustion oscillation. In addition, by comprehensively considering the influence of secondary combustion on emissions and combustion oscillation, the operating range and load increasing mode of low emissions and stable combustion of axial staged combustor in the higher load range (20%—50% load) are obtained, which provides a reference for stable low emission operation of the unit during load increasing.

Agricultural diesel engines can be operated continuously under complex and variable conditions for extended periods. The higher requirements are posed on the Diesel Particulate Filter (DPF) regeneration and reliability. This study aims to enhance the safe and efficient performance of DPF regeneration, emissions, and fuel economy of agricultural diesel engines. An intelligent multi-objective optimization was also proposed to enhance multiple cyclic training. Taking the agricultural engines as the research object, the sample data of the bench test was obtained after experimental design. A prediction model was then constructed in the conditions of DPF regeneration using a Back Propagation neural network (BPNN). According to the Seagull Optimization Algorithm (SOA), the Adaptive Memory Seagull Optimization (AMSO) was proposed to optimize the structure parameters of the BPNN model, in order to meet the requirements of precision. The targets of optimization included T4, T5, O2 concentration, Brake Specific Fuel Consumption (BSFC), NOx, and smoke opacity. In the specific conditions of agricultural diesel engines, multi-objective optimization of injection and intake control parameters was realized under regeneration mode using the Non-dominated Sorting Genetic Algorithm (NSGA)-III. The AMSO-BP prediction model was used to evaluate the fitness of the Pareto optimal solutions, in order to validate the NSGA-III optimal dataset. The optimized MAP values were written into the Engine Control Unit (ECU) after bench tests. Steady-state and World Harmonized Transient Cycle (WHTC) experiments were carried out to verify the multi-objective optimization of the model. The results indicate that the AMSO significantly outperformed the SOA in the optimization of the BPNN prediction model. The AMSO-BPNN prediction model more accurately utilized experimental data to predict the T4, T5, O2 concentration, BSFC, NOx, and smoke opacity, with the R² values of 0.97, 0.99, 0.95, 0.99, 0.98, and 0.95, respectively, on the validation set. Furthermore, the Mean Absolute Percentage Errors (MAPE) on the validation set were reduced by 0.1%, 0.33%, 0.8%, 0.04%, 0.08%, and 4.2%, respectively, compared with the SOA-BP model. The steady-state tests before and after optimization showed that T4 and T5 increased by an average of 3.14%, where the concentration of exhaust oxygen increased by 2.07% and 10.79%, respectively. Simultaneously, the average reductions in the NOx, smoke opacity, and BSFC were 8.68%, 12.07%, and 1.03%, respectively. Efficient and safe DPF regeneration was achieved to significantly reduce the emissions of diesel engines. There was particularly notable optimization under the operation of agricultural diesel engines, which were often working at low speeds and high loads, fully meeting the usage requirements of these engines. The WHTC transient test also showed that the effectiveness of the optimization was achieved in the T4, T5, and O2 concentrations, which increased by 31%, 2.6%, and 0.5%, respectively. Additionally, NOx and soot emissions decreased by 10.4% and 0.8%, and BSFC was reduced by 3.5%. These findings demonstrate that better performance was obtained under the complex and variable conditions of agricultural diesel engines. In conclusion, the safe and efficient DPF regeneration can be expected to reduce the emissions and operational costs for agricultural diesel engines. The specific requirements of agricultural diesel engines can also be fully met to enhance the system reliability in the engineering application. This research can offer practical guidance to optimize the control parameters under the regeneration mode of diesel engines, particularly for more sustainable and efficient agricultural machinery. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Shanghai Jiao Tong University (1006-2467) is the property of Journal of Shanghai Jiao Tong University Editorial Office 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.)

Copyright of Journal of Engineering for Thermal Energy & Power / Reneng Dongli Gongcheng is the property of Journal of Engineering for Thermal Energy & Power 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.)

Copyright of Journal of Chongqing University of Technology (Natural Science) is the property of Chongqing University of Technology 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.)

Copyright of Journal of Agro-Environment Science is the property of Journal of Agro-Environment Science Editorial Board 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.)

Based on the diesel engine bench equipped with diesel oxidation catalyst (DOC) and diesel particulate filter (DPF), the flue gas analyzer of Testo 350XL and the engine exhaust particle size spectrometer of TSI EEPS 3090 were used to investigate NOx and particulate matter (PM) variation under different loads before and after the DOC and after the DPF. The results show that the NO2 volume fraction of φ (NO2) is increased significantly after DOC when the load is greater than 50.0%. With the increasing of engine load, NO2 volume fraction in nitrogen oxides φ (NO2/NOx) of the raw diesel engine is decreased, while the φ (NO2) and φ (NO2/NOx) of the DOC and the DPF are decreased first with latter increasing. The raw diesel engine PM emission is depended on the operation conditions of the diesel engine. The PM removal rate of DOC is 15%-30% under different loads, and the PM removal rate of DOC under 50.0% load has the highest value of 26%. The PM removal rate of DPF is exceeded 90%. The nucleated particles volume fraction after DPF is increased, while aggregated particles volume fraction is decreased. [ABSTRACT FROM AUTHOR]

Copyright of China Rubber Industry is the property of Editorial Office of China Rubber Industry 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.)

Copyright of Automotive Engineer (1674-6546) is the property of Auto Engineering Editorial Office 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.)

BackgroundAt present, only the rare earth industry has established discharge limits for waste water generated from associated radioactive mines. Liquid effluent from associated radioactive mines industries other than rare earths should satisfy with the requirements of Integrated Wastewater Discharge Standard (IWDS). However, discharge limits of IWDS are disputable to be implemented, hence not suitable for the development and utilization of associated radioactive mines.PurposeThis study aims to consider the need of establishing designated standards of discharge limits on liquid effluent from related radioactive mines wastewater.MethodsFirstly, investigation was conducted on the types and concentration of radionuclides of wastewater from associated radioactive mine, as well as the level of radioactive wastewater treatment technology. Results on the discharge limits for natural radioactive isotopes both in China and abroad were examined and compared. Then, the types of radionuclides and discharge limits to be controlled in the development and utilization of liquid effluent from associated radioactive mines were studied in a scientific manner. Finally, the method of establishing discharge limits for liquid effluents from associated radioactive mines by referring to the uranium mining and metallurgical industries was proposed.Results & ConclusionsThe specific standard on discharge limits for wastewater treatment from associated radioactive mines has a significant impact on regulating the discharge of effluent in China and reducing the radiation environmental impact of associated radioactive mines. It is reasonable to refer to the standard limits of uranium mining and metallurgy. Liquid effluent from associated radioactive mines industries other than rare earths should satisfy with the requirements of IWDS.

During the process of 131I-labeled radiopharmaceuticals production, the radioactive waste gas accumulated in the vials will be released immediately when the vial of 131I solution is opened, and it will cause pollution. A set of device for collecting radioactive waste gas from 131I solution vials was developed, based on radiation resistance, operation convenience and versatility of device and the size of hot cell. The purpose of semi-automatic collection and temporary storage of radioactive waste gas was realized and the collected radioactive waste gas was measured and analyzed. The results showed that the equipment ran stably and reliably. The study of 22 batches shows that, the amount of 131I waste gas collected had a certain correlation with the ambient temperature. Three collecting bottles can fully collect the waste gas generated. In summary, the device for collecting radioactive waste gas can effectively collect the radioactive waste gas released from 131I solution, reducing the impact on the environment and operators, and has great reference significance for other radioactive drug companies.

Copyright of Electroplating & Finishing is the property of Electroplating & Finishing Editorial Office 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.)

Copyright of Automobile Technology is the property of Automobile Technology Editorial Office 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.)

Based on the strong nonlinear approximation and self-learning ability of Back Propagation (BP) neural network, a three-layer network model was designed, and the engine bench test data were collected as the samples to train and verify the model. The engine speed, torque, fuel supply advance angle and the characteristic parameters of the fuel mixture of Fischer-Tropsch gas-to-liquid (GTL) and diesel, such as cetane number, sulfur content and aromatic hydrocarbon content, were taken as inputs. The BP neural network model was established to predict the characteristics of GTL engine. The results show that the model can predict the power, fuel consumption, exhaust temperature, HC, CO, CO2, NOx and soot emission of GTL engine at the same time. Compared with the experimental data, the relative error of the prediction results is nearly within 5%, which shows that the model has high model accuracy and good generalization ability. [ABSTRACT FROM AUTHOR]

Aimed at improving the prediction accuracy of engine emissions under driving conditions which are not covered by the training set, an extrapolated Gaussian process regression (GPR) method is proposed. First, the training set data is fed to the GPR model for pre-training, and then a wide-area input set is constructed by uniform sampling between plus/minus three standard deviations, and the hyperparameters are optimized for the goal of minimizing the prediction variance of the input set. The test results on a direct injection gasoline engine show that the mean absolute error of emission prediction using the extrapolated GPR is 0.53411, which is 24.27% lower than that of using the traditional GPR and 36.32% lower than that of using the back propagation (BP) neural network, which signifies the effectiveness of the proposed method in terms of reducing test costs and improving the accuracy of emission prediction during real driving.

In this paper, it is introduced volatile organic compounds (VOCs) calculation method about the crude oil external floating roof storage tanks. Taking the petroleum depot composed of 12 sets of 100 dam3 of crude oil external floating roof storage tanks with an annual turnover of 10 million tons as the research object, the influence of the VOCs emissions of the parameters such as different seal forms, shell clingage and deck fittings are compared and discussed, and the main influence factors are summarized and analyzed. The results show that the VOCs emission can be reduced by 70% after adding the secondary seal; The VOCs emission under the heavy rust condition is nearly 100 times that under the light rust condition; The VOCs emission of the deck fittings with seals can also be reduced by 36.5% compared with the deck fittings without seals; The withdrawal loss is the largest source of VOCs emission, through the comparative analysis of the two combined conditions. In combination with the current national management requirements and technical and economic conditions, the selection and management suggestions for reducing VOCs emissions of external floating roof storage tanks are put forward, such as primary high-efficiency sealing and secondary sealing, sealing of deck fittings, and increasing tank cleaning frequency. [ABSTRACT FROM AUTHOR]

Copyright of China Rubber Industry is the property of Editorial Office of China Rubber Industry 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.)

Copyright of Journal of Beijing University of Technology is the property of Journal of Beijing University of Technology, Editorial Department 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.)

Copyright of Journal of Shanghai Jiao Tong University (1006-2467) is the property of Journal of Shanghai Jiao Tong University Editorial Office 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.)

A diesel engine has been widely used in ground transportation, agricultural machinery, and sea shipments, due mainly to its excellent reliability and high thermal efficiency. However, the fuel emission and consumption of diesel engines have posed a great threat to the ecological environment in recent years. Therefore, it is very necessary to improve the combustion and emission performance of diesel engines, further to meet the specific requirement of national environmental regulations. Diffusion combustion can generally dominate the combustion process in the direct injection diesel engine. The mixing quality of fuel and air can be expected to serve as the most effective means for the higher performance of diffusion combustion. Different techniques have also emerged to optimize the combustion quality of the fuel/air mixing process in modern diesel engines. For instance, the special geometry structure of the combustion chamber has been adopted to utilize the momentum of the high-pressure fuel jet in the wall-flow-guided combustion system, where the diffusion can be guided in the chamber by the effect of the spray jet hitting the wall. As such, the air utilization rate can be improved for the high combustion and emission performance of a direct injection diesel engine. Both lateral swirl combustion system (LSCS) and separated swirl combustion system (SSCS) have been specially designed for the wall diversion structure in the combustion chamber, where the spray in the cylinder can be guided to form a swirl motion for the high quality of fuel/air mixing process. Nevertheless, the two combustion systems behave in different in-cylinder fuel spray strategies. In this study, a single-cylinder diesel engine was selected to verify the combustion performance of the LSCS and SSCS under different loads and excess air coefficients. AVL Fire software was used to explore the fuel/air mixing mechanism of the combustion system. The test results show that the fuel consumption rate, soot emission, and combustion duration of LSCS under various loads were reduced by 2.4-7.8 g/(kW·h), 2.7-3.9 FSN, and 5.6-10.7 °CA, respectively, compared with the SSCS. Under different excess air coefficients, the fuel consumption rate, soot emission, and duration of combustion were reduced by 3.2-9.8 g/(kW·h), 2.3-3.8 FSN, and 7.9-10.0 °CA, respectively. The maximum drop of LSCS in the fuel consumption and soot emission were 4.3%, and 87.0%, respectively. The simulation results show that the spray jet impinged the convex edge in the LSCS, leading to the wall jets scrolling to form two lateral swirls. The two adjacent spray jets produced the wall jet interference, when flowing out of the convex edge, further improving the air utilization rate. By contrast, there was the fuel aggregation, as the position of the spray jet touched the wall, particularly when the piston was moving down in the SSCS, which was not conducive to the fuel/air mixing process. That is why the air entrainment quantity of the LSCS increased by 9.3%, compared with the SSCS. There was a smaller fuel mass ratio in the interval of equivalent ratio 2-4, whereas, the larger in the interval of equivalent ratio <1-2, indicating the better uniform fuel/air mixing of the LSCS. Therefore, the LSCS can be widely expected to outstandingly improve the fuel/air mixing process, and the combustion performance of the direct injection diesel engine with less soot generation. The finding can provide a technical reference for the structural design and optimization of the combustion chamber in the direct injection diesel engine. [ABSTRACT FROM AUTHOR]

Copyright of Experimental Technology & Management is the property of Experimental Technology & Management Editorial Office 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.)

Copyright of Natural Gas & Oil is the property of Editorial Department of Natural Gas & Oil 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.)

Copyright of Journal of Shanghai University / Shanghai Daxue Xuebao is the property of Journal of Shanghai University (Natural Sciences) Editorial Office 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.)

An abundant supply of stover in northern China remains after corn grain harvest. The collected stover resources are about 6.74×108 t in 2017. Converting stover bales into renewable energy for clean heating is attracting much attention to save many stover resources, further possibly to replace coal, and thereby positively contribute to air quality, rural communities, and society at large. According to the whole life cycle in sustainable agriculture, in this study, a systematic evaluation was carried out to use a 3E (Economic, Energy and Environment) model, ranging from crop planting and harvesting to stover burning for heating, in order to explore the energy efficiency, economic benefits, and greenhouse gas emissions of baled stover burning boiler for clean heating. The results showed that the heating from baled stover burning has better energy and economic benefits, with less emissions of greenhouse gas. The clean heating can be expected suitable for the heating in winter in villages and towns with concentrated living, and for the urban district heating, such as agricultural and industrial parks. The heating area ranged from 5 000 to 100 000 m², the net energy of baled stover for heating was 10 512-10 774.8 MJ/t, and the energy output-input ratio was 8.4-8.5, indicating that the energy conversion rate was relatively high. In addition, the greenhouse gas emissions (CO2 eq.) were 9.67-11.21 g/MJ. The total cost of heating by burning stover bales was 391.1 yuan/t (equivalent to 16.2 yuan/m²) -560.5 yuan/t (equivalent to 23.8 yuan/m²). Calculating at an 8% rate of return, the heating scale can be more than 20 000 m². If only considering operating costs without the depreciation, the heating area can be more than 10 000 m2. The baled stover burning for heating can achieve the best energy efficiency, while the least emissions of greenhouse gas, compared with stover densified biofuel, and stover carbon-gas co-generation. The net energy output of three stover heating can be less than that of coal heating, but the greenhouse gas emissions can be only from 1/10 to 1/7 of that of coal, indicating the environmental benefits are significant. Therefore, it is highly recommended to further improve the heating facilities in villages and towns of northern China, and thereby promote the application of clean heating, such as baled stover burning, densified biofuel, and pyrolysis carbon-gas cogeneration. Stover clean heating can be used to effectively alleviate air pollution and reduce emissions of greenhouse gas in a renewable energy source. [ABSTRACT FROM AUTHOR]

The emission of aero piston engines has been a focused problem. The combustion chamber size is of certain effect on engine emissions performance. A piston engine is taken as the object of study. Fire is used to establish a type of engine combustion chamber model from the perspective of combustion spray model. Improvement based on geometric parameters of existing combustion chamber are proposed; and simulation analysis is carried out under the new program; the nitrogen and oxygen compounds and carbon emissions between the old and new program are compared in a transient state. The results show that the emission of nitrogen and oxygen compounds under the new combustion chamber structure is reduced by 23%, the carbon emission is reduced by 2.8%, and the overall emission is decreased. After installing the modified combustion chamber into the engine and maintaining the engine power and torque unchanged, a reduction in emission is clearly shown, which proves that the design program is feasible.

Copyright of Tobacco Science & Technology is the property of Tobacco Science & Technology 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.)

Methane (CH4), carbon dioxide (CO2) and nitrous oxide (N2O) are three of important greenhouse gases discharged by paddy fields. Reducing greenhouse gas emissions from paddy fields plays a crucial role in slowing global warming. In order to evaluate the influence of different water and fertilizer management modes on CH4, CO2 and N2O emissions in paddy fields and to find out a recommended mode from the perspective of reducing greenhouse gas emission and maintaining rice yield, a field experiment was carried out to determine the effects of six treatments including two irrigation methods (intermittent irrigation and flooding irrigation, referred to as W1 and W0, respectively) and three application rates of nitrogen fertilizer (0, 135, 180 kg/hm2, referred to as N0, N1 and N2, respectively) on CH4, CO2 and N2O emissions in the medium rice fields between June and September, 2019. The test site was located at the experimental base (115°58ʹ E, 28°26ʹ N) of the Jiangxi Province Center Station of Irrigation Experiment, in the Ganfu Plain of Poyang Lake Basin characterized by a typical subtropical and humid monsoonal climate with an annual average temperature of 18.1 ℃ and an annual average rainfall of 1 634 mm. Closed static dark chamber-gas chromatography was used to collect gas fluxes during the rice-growing seasons and measure the diurnal variation of greenhouse gases in three typical days and dynamics of CH4, CO2 and N2O emissions during the whole growth season of rice. The Global Warming Potential (GWP) was calculated based on CO2 equivalents and combined with the yields to obtain the Greenhouse Gas Emissions Intensity (GHGI) of every treatment. The results showed that diurnal variation of CH4 and CO2 emissions were similar with single-peak curves and the peak occured at noon, and N2O emissions showed a trimodal curve pattern during the typical day. The time period of 08:00-11:00 a.m. was recommended to collect gas fluxes based on analysis of correction factors at different time periods. Irrigation treatments had an extremely significant effect on the CH4 emissions during the rice growing season, and accumulative CH4 emissions under W0 were higher than that under W1. The CO2 emission of N0 treatment was lower than that of N2 and N1 under W1, and also lower than that of N2 and N1 under W0. The N2O emission of N0 treatment was also lower than that of N2 and N1 under W1, and lower than that of N2 and N1 under W0. The treatment of W0 reduced CO2 and N2O emissions compared to W1. Soil and air temperature were both important environmental factors affecting greenhouse gas emissions from paddy fields. Based on regression analysis between greenhouse gases from paddy fields and temperature, the daily emission flux and temperature of CH4 and CO2 had significant effects at the levels of 0.01 and 0.05, respectively. The sensitivity of CH4 and CO2 to soil temperature at 10 cm was higher than that of air temperature in chambers. Compared with a typical day in August, the temperature sensitivity of a typical day in September was higher, and the difference between sensitive coefficients to air temperature and soil temperature was larger. In addition, two-way analysis of variance showed that water-fertilizer interactions had an extremely significant effect on both GWP and GHGI. The treatment of intermittent irrigation combined with reduced nitrogen fertilizer application rate (135 kg/hm2) had the lowest GHGI, and thus was a recommended water and fertilizer management mode for the paddy field in the Poyang Lake Basin. [ABSTRACT FROM AUTHOR]

Idle is one of the important operating conditions for non-road diesel engines. In China III, IV stage emission regulations from diesel engines for non-road mobile machinery, the proportion of idle condition in the eight-condition steady-state test cycle is 15% for the diesel engine operating at non-constant speed, and its ratio is 5% in the six-condition steady-state test cycle for the diesel engine with rated net power less than 19 kW and operating at unsteady speed. In China IV stage of non-road transient cycle (NRTC), the idle condition accounts for 4.52%. Due to the fact that the idle condition does not output power and also the fuel injection amount is small, the air-to-fuel ratio is relatively large and the combustion is incomplete at this time, which results in a large amount of fuel consumption and high emission of harmful gases. The land area with an altitude of more than 1 000 m in China is about 58% of the total area of the country, and proportion is about 33% for the plateau area with an altitude of more than 2 000 m. A large number of agricultural machinery powered by diesel engines operate at these areas. Compared with the sea level, atmospheric pressure will decline in plateau areas, the intake air mass flow rate decreases, and the operating performance at idle condition will further deteriorate. In order to investigate the effects of atmospheric pressure on combustion characteristics and emission performance of a small agricultural diesel engine at idle condition, the change law of combustion and emission performance of the small agricultural diesel engine, which meets the emission standard of China III non-road mobile machinery, was studied at different atmospheric pressures such as 80, 90, 100 kPa by using atmospheric pressure simulator. The experimental results demonstrated that the turbocharger matched with the small agricultural diesel engine did not work, and also the turbocharger system did not have self-compensation capability in plateau area at idle condition. Peak in-cylinder pressure, peak in-cylinder pressure rise rate, and peak heat release rate all go up with an increasing of atmospheric pressure; the average increase rate were 13.33%, 37.24% and 6.76%, respectively, with atmospheric pressure increased per 10 kPa. However, peak in-cylinder combustion temperature showed a decreased tendency with atmospheric pressure increased; the average decrease rate was 11.18% with atmospheric pressure increased per 10 kPa. Atmospheric pressure had a great influence on carbon monoxide (CO) emission and hydrocarbon (HC) emission. CO emission and HC emission declined sharply with an increasing of atmospheric pressure; the average decrease rate were 47.47% and 55.77%, respectively, with atmospheric pressure increased per 10 kPa. The variation range of nitrogen oxides (NOx) emission and smoke were relatively small with atmospheric pressure increased. With atmospheric pressure increased per 10 kPa, the average NOx emission increased 18.93%, while the average smoke reduced 11.90%. This research can provide a reference for the establishment of emission control strategy for a small agricultural diesel engine at idle condition in a plateau area. [ABSTRACT FROM AUTHOR]

The aim of Paris Agreement is to strengthen the global greenhouse gas emission reduction action to hold global warming. To achieve this goal, countries submitted mitigation plans in the form of "Intended Nationally Determined Contributions" (INDC). The climate response to INDC emission reduction is a focus in climate change research. However, few studies evaluated the possible changes in regional extreme temperature under the INDC emission pledges. In this research, the simulations of 32 global climate models (GCMs) from the Coupled Model Intercomparison Project Phase 5 (CMIP5) were applied to investigate the changes in extreme temperatures in Central Asia under INDC-pledge scenario above present-day level, characterized by nine extreme temperature indices. Our results show that future extreme high temperature events were estimated to increase significantly, while extreme low temperature events were estimated to decrease significantly. Nighttime warm extremes were projected to increase more than daytime warm extremes. There are some differences in the spatial patterns of changes in various extreme temperature indices. The Pamirs and high latitudes are the most sensitive areas of extreme temperature changes. We further found an approximately linear relationship between most regional extreme temperature indices and global mean warming. Our results indicate that if global emission reductions are further strengthened to achieve the ambitious temperature target of global 2℃ or 1.5℃ goals, the avoidance on regional extreme temperature events is projected to be pronounced. [ABSTRACT FROM AUTHOR]

【Objective】 The present paper aimed to explore the effect of light on CO2 exchange at the root and leaf interfaces of rice with different growth stages, 【Method】A self-designed gaseous compound volatilization test device was used in the experiment to determine the CO2 exchange rate at the leaf and rhizosphere interfaces of rice under the conditions of close separation and simultaneous measurement in the inner and outer chambers. 【Result】（i）Under natural sunlight, the rice phyllosphere CO2 exchange rate in the daytime at tillering stage, flowering and seed setting stage and mature aging rice plants was-13.58,-10.84 and 27.36 μg/pot·h, respectively. It showed that rice phyllosphere was an important CO2 sink at early-middle rice growth stage, and as well an important source of CO2 emission at mature aging stage. In early-middle period, CO2 emissions of the rice plants were mainly from rice phyllosphere at night time.（ii）Under weak illumination, there were a large number of CO2 emissions from rice phyllosphere and rhizosphere at different rice growth stages, but the main CO2 emissions mainly came from rice phyllosphere. Compared with LED green and yellow light, CO2 emissions of rice phyllosphere was inhibited markedly by red and blue light. 【Conclusion】In summary, increasing the ratio of red and blue light and light intensity in different growth periods, the effect of reducing CO2 emissions from rice ecosystems should be reduced. [ABSTRACT FROM AUTHOR]

In order to study the effect of natural gas and hydrogen mixed fuel on the combustion and emissions of the engine, biodiesel was used as the fuel, and a comparative experimental study was conducted in the reactivity controlled compression ignition (RCCI) mode. The test results show that natural gas doped with hydrogen improves the thermal efficiency of diesel engines, while shortening the flame retardation period and the duration of combustion; with the increase of injection volume of natural gas doped with hydrogen mixture fuel, the peak value of heat release increases first and then decreases, and the ignition time is delayed. The HC, CO and smoke emissions of natural gas hydrogenated fuels are lower than natural gas, but NOx emissions are on the rise. Compared with traditional diesel engines, natural gas doped with hydrogen can significantly reduce CO and HC emissions. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Beijing University of Technology is the property of Journal of Beijing University of Technology, Editorial Department 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.)

Copyright of Journal of Engineering for Thermal Energy & Power / Reneng Dongli Gongcheng is the property of Journal of Engineering for Thermal Energy & Power 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.)

Taking biodiesel/diesel as research object, by AVL-Fire software and Chemkin software, the biodiesel/diesel chemical reaction kinetics model was constructed to investigate the effects of blending ratio and EGR rate of biodiesel/diesel on the soot precursor formation of acetylene, benzene, naphthalene, phenanthrene and pyrene. The results show that the soot precursor is mainly formed in the premixed combustion stage. With the increasing of crank angle, the soot precursor content is increased with latter decreasing. With the increasing of biodiesel blending ratio, the initial formation time of soot precursor is advanced, and the peak amount of production and the final amount of production are reduced. With the increasing of EGR rate, the peak formation timing is delayed, and the production peak of acetylene is reduced with gradually increased final amount. The final amount of benzene, naphthalene, phenanthrene and pyrene is increased. [ABSTRACT FROM AUTHOR]

Transport of dust sand caused by wind erosion is a serious problem in many arid regions in the world, and it plays animportantrolein global biogeo chemical cycle. The dust induced by transport of aeolian sand can affect atmospheric radiation balance, climate, environment, air quality and human health. It has hence attracted increased attention in various areas ranging from geomorphology and climatology to meteorology and ecological-environmental science. In addition to its natural origin, dust could also be instigated by anthropogenesis activities due to desertification.However, the relative contribution of the two origins is still an issue remaining elusive. In addition, being able to accurately estimate the potential of a dust source is crucial to evaluating the influence of desertification and climate change on dust flux. The Taklimakan desert(TD) is the second largest shifting sand desert in the world, with about 85% made up by shifting sand dunes.It is an important source of the dusts seen in China. Understanding particle size distribution of the sand and dust emission is helpful to evaluate quality of the atmospheric environment and the consequence for climate at regional scale. We collected 138 samples from soil surface based on spatial distribution and types of the surfaces including farmland, dune and desert. Particle sizes of each sample was analyzed using the Mastersizer 2000 laser particle size analyzer, and the associated dust release flux was calculated using the DPM model.The particle size distribution of the micro aggregates in each sample was obtained to elucidate its potential influence on dust release flux. The results showed that: 1) The content of silt and clay in the 138 samples was least, accounting for 10% to 18% of the total particles in the mobile sand dunes, and 20% to 30% of the total particles in the sand ridges (e.g., sandy soil and sandy-sandy loams). Most samples taken from farmland (e. g., oasis and forest belt) are meadow soil, with silt and clay content being 50%-80%, differing from the silt and clay content in samples taken from the Gobi (desert area). 2) Fine sand and silty-fine sand are the smaller particles in the surface soil and can be divided into three groups, each described by a log normal distribution: silt-fine sand group, fine sand group and coarse sand group, with median particle size being 90, 225 and 500 μm, and the standard deviation being 1.02, 1.53 and 1.08, respectively, accounting for 30%, 49% and 21% respectively. 3) Emission of silt-fine sand and fine sand is most potential, followed by medium-coarse sand. The coarse sand is least to emit; the difference between the maximum and the minimum emission was in the order of 10-2μg/(m²·s) in magnitude. The results reflect the difference in dust emission from different soil surfaces and they are greatly important for quantitative assessment of dust emission in the studied region and beyond [ABSTRACT FROM AUTHOR]

As mining progresses to deeper development, the impact of ground pressure activities on mining is becoming more and more significant. The application of acoustic emission source localization technology can effectively monitor the ground pressure in real time and provide guidance for safe production. Positioning accuracy is also the top priority of acoustic emission source positioning. The time difference positioning algorithm is more common. The time difference linear positioning algorithm mainly constructs linear equations for algebraic method, which the method is simple, while the disadvantage is that the equations may have no solution and the positioning calculation fails. The Geiger iterative localization algorithm performs multiple iterations on the basis of selecting the appropriate iteration initial value to obtain the positioning result. In principle, the linear positioning algorithm is more accurate than the time difference linear positioning algorithm. In this paper, the linear positioning and Geiger iterative positioning algorithm in time difference positioning were combined with the acoustic emission events in Yunnan monitored by the acoustic emission monitoring system of large iron ore and analyzed. The error analysis of the positioning results obtained by the two positioning algorithms was used to specify the applicability and accuracy of the two methods for engineering practice. [ABSTRACT FROM AUTHOR]

A zinc ion fluorescent probe molecule with pyrazine group is studied by density functional theory. The ground state equilibrium geometry, absorption properties, orbital energy, excited state geometry and emission properties were studied theoretically. The results show that when the probe molecule is bound to zinc ion, the zinc ion complex exhibits better symmetric structure. The absorption wavelength and emission wavelength are blue shifted, simultaneously, the oscillator strength increases. In addition, the change of electron cloud reflects the charge transfer in the molecule. The synthesized results show that the probe molecule can detect zinc ions. [ABSTRACT FROM AUTHOR]

Copyright of Research of Environmental Sciences is the property of Research of Environmental Sciences Editorial Board 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.)

Copyright of Research of Environmental Sciences is the property of Research of Environmental Sciences Editorial Board 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.)

Copyright of China Sciencepaper is the property of China Sciencepaper 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.)

Copyright of Journal of Beijing University of Technology is the property of Journal of Beijing University of Technology, Editorial Department 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.)

Copyright of Journal of Engineering for Thermal Energy & Power / Reneng Dongli Gongcheng is the property of Journal of Engineering for Thermal Energy & Power 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.)

To study the influence of coal-based F-T diesel fuel on the performance of explosion-proof diesel engine, 0# diesel oil and F-T diesel oil were respectively burned in the explosion-proof diesel engine equipped with an intake and exhaust flame arrester and a water-washing tank on the engine bench test. The results show that compared with the national VI 0# diesel oil, the economy of the explosion-proof diesel engine is improved and the emission of harmful pollutants is decreased sharply when using F-T diesel oil. Even the power decreases slightly, it can also completely meet the requirements of application. In the case of external characteristics with the combustion of F-T diesel oil, the full consumption rate is decreased by 10.9% on average, while the emissions of CO, NOx and PM are decreased by 80.2%, 11.5% and 30.6% respectively. At the 11 operating points, the CO, NOx and PM emissions are decreased by 85.7%, 33.9% and 43.4% respectively. This research shows that the F-T diesel oil can be used as a good clean alternative fuel for explosion-proof diesel engine. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Engineering for Thermal Energy & Power / Reneng Dongli Gongcheng is the property of Journal of Engineering for Thermal Energy & Power 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.)

Copyright of Research of Environmental Sciences is the property of Research of Environmental Sciences Editorial Board 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.)