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Field test of high-power microwave-assisted mechanical excavation for deep hard iron ore 被引量:1
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作者 Feng Lin Xia-Ting Feng +5 位作者 Shiping Li Xiao Hai Jiuyu Zhang Xiangxin Su Tianyang Tong Jianchun Song 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第6期1922-1935,共14页
Microwave-assisted mechanical excavation has great application prospects in mines and tunnels,but there are few field experiments on microwave-assisted rock breaking.This paper takes the Sishanling iron mine as the re... Microwave-assisted mechanical excavation has great application prospects in mines and tunnels,but there are few field experiments on microwave-assisted rock breaking.This paper takes the Sishanling iron mine as the research object and adopts the self-developed high-power microwave-induced fracturing test system for hard rock to conduct field experiments of microwave-induced fracturing of iron ore.The heating and reflection evolution characteristics of ore under different microwave parameters(antenna type,power,and working distance)were studied,and the optimal microwave parameters were obtained.Subsequently,the ore was irradiated with the optimal microwave parameters,and the cracking effect of the ore under the action of the high-power open microwave was analyzed.The results show that the reflection coefficient(standing wave ratio)can be rapidly(<5 s)and automatically adjusted below the preset threshold value(1.6)as microwave irradiation is performed.When using a right-angle horn antenna with a working distance of 5 cm,the effect of automatic reflection adjustment reaches the best among other antenna types and working distances.When the working distance is the same,the average temperature of the irradiation surface and the area of the high-temperature area under the action of the two antennas(right-angled and equal-angled horn antenna)are basically the same and decrease with the increase of working distance.The optimal microwave parameters are:a right-angle horn antenna with a working distance of 5 cm.Subsequently,in further experiments,the optimal parameters were used to irradiate for 20 s and 40 s at a microwave power of 60 kW,respectively.The surface damage extended 38 cm×30 cm and 53 cm×30 cm,respectively,and the damage extended to a depth of about 50 cm.The drilling speed was increased by 56.2%and 66.5%,respectively,compared to the case when microwaves were not used. 展开更多
关键词 Microwave parameters High power field experiment Mechanical mining
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The Longmen Cloud Physics Field Experiment Base, China Meteorological Administration 被引量:3
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作者 刘显通 阮征 +18 位作者 胡胜 万齐林 刘黎平 罗亚丽 胡志群 黎慧琦 肖辉 雷卫延 夏丰 饶晓娜 冯璐 赖睿泽 吴翀 叶朗明 郭泽勇 张羽 王瑶 颜朝潮 袁锦涵 《Journal of Tropical Meteorology》 SCIE 2023年第1期1-15,共15页
Aiming at the needs of mechanism analysis of rainstorms and development of numerical prediction models in south China, the Guangzhou Institute of Tropical and Marine Meteorology of China Meteorological Administration ... Aiming at the needs of mechanism analysis of rainstorms and development of numerical prediction models in south China, the Guangzhou Institute of Tropical and Marine Meteorology of China Meteorological Administration and the Chinese Academy of Meteorological Sciences jointly set up the Longmen Cloud Physics Field Experiment Base,China Meteorological Administration. This paper introduces the instruments and field experiments of this base, provides an overview of the recent advances in retrieval algorithms of microphysical parameters, improved understanding of microphysical characteristics, as well as the formation mechanisms and numerical prediction of heavy rainfalls in south China based on the field experiments dataset. 展开更多
关键词 cloud physics heavy rainfall field experiment south China
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Field experiments to improve the efficacy of gargoor (fish trap) fishery in Kuwait's waters
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作者 陈卫忠 AL-BAZ Ali +1 位作者 BISHOP James M. AL-HUSAINI Mohsen 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2012年第4期535-546,共12页
Fish traps were investigated to understand the effects of season, bait type, trap size, and trap soak time on catch rates, catch composition, and trap loss rates from March 2004 to September 2005, to improve the perfo... Fish traps were investigated to understand the effects of season, bait type, trap size, and trap soak time on catch rates, catch composition, and trap loss rates from March 2004 to September 2005, to improve the performance and management of Kuwait's gargoor (cage style fish trap) fishery, which used to be the nation's most important one in terms of value and landings volume. Catch rates were the highest in April/May (5 8 kg/trap haul) and again in December (7 kg/trap haul). Bait type and trap size also affected catch rates and species composition. Of the seven baits tested, the best catch rates, 〉5 kg/trap haul, occurred with cuttlefish (Sepia pharaonis), but wolf-herring (Chiroeentrus dorab) and mullet (Liza klunzingeri) also produced good results (4-5 kg/trap haul). Within the five tested sizes, the two largest-sized traps captured more fish and larger size fish. Analysis of variance (ANOVA) showed significant differences of catch rate among traps with different baits as well as among traps of different sizes. Duncan test further revealed these differences between two specific baits and sizes. Cluster Analysis of species composition showed more differences among different baits than among different trap sizes. Longer soak times did not result in larger catch rates, but increased trap loss. About 10-day soak time resulted in trap loss 7%, while 40-day soak time could result in a loss of around 20%. Consequently, it is recommended that the gargoor be checked every 10 or fewer days. The average overall catch rate during the study period was lower than that of 1980s (4.5 vs. 5.8 kg/trap haul), indicating a possible decline offish abundance in Kuwait's waters. It is recommended that the number of gargoor fishing boats and gargoors from each boat should be limited to allow stock rehabilitation. 展开更多
关键词 field experiment fish trap improvement of efficacy catch rate KUWAIT
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Observational results of electromagnetic radiation caused by explosion of small dimension rocks in field experiments
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作者 金安忠 赵强 +4 位作者 姜枚 刘煜洲 王寅生 刘希强 张继红 《Acta Seismologica Sinica(English Edition)》 CSCD 1997年第1期52-59,共8页
In order to probe the mechanism of the phenomena of seismic electromagnetic radiation (EMR), we have completed field experiment on EMR caused by explosiom of rocks. In the experiments, the data of medium lo... In order to probe the mechanism of the phenomena of seismic electromagnetic radiation (EMR), we have completed field experiment on EMR caused by explosiom of rocks. In the experiments, the data of medium low freguency (<5000 Hz) EMR caused by 26 explosion tests of small dimension rocks have been obtained. This paper shows some representative observational results of the field experiment. The observational results show that, nearly 20 points of the 26 explosive points, the EMR phenomena are recorded at various degrees in the related explosive processes. The EMR intensities decay with the distance from explosive origins and increase with the explosive energy. The EMR records have certain repeatability (under the same condition), complexity( multiple EMR effects caused by one explosion) and regional characteristics such as rock structure and observational direction etc. 展开更多
关键词 explosion of rock ELECTROMAGNETIC RADIATION field experiment regional characteristics
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Propagation Characterization and Analysis for 5G mmWave Through Field Experiments
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作者 Faizan Qamar Mhd Nour Hindia +3 位作者 Tharek Abd Rahman Rosilah Hassan Kaharudin Dimyati Quang Ngoc Nguyen 《Computers, Materials & Continua》 SCIE EI 2021年第8期2249-2264,共16页
The 5G network has been intensively investigated to realize the ongoing early deployment stage as an effort to match the exponential growth of the number of connected users and their increasing demands for high throug... The 5G network has been intensively investigated to realize the ongoing early deployment stage as an effort to match the exponential growth of the number of connected users and their increasing demands for high throughput,bandwidth with Quality of Service(QoS),and low latency.Given that most of the spectrums below 6 GHz are nearly used up,it is not feasible to employ the traditional spectrum,which is currently in use.Therefore,a promising and highly feasible effort to satisfy this insufficient frequency spectrum is to acquire new frequency bands for next-generation mobile communications.Toward this end,the primary effort has been focused on utilizing the millimeter-wave(mmWave)as the most promising candidate for the frequency spectrum.However,though the mmWave frequency band can fulfill the desired bandwidth requirements,it has been demonstrated to endure several issues like scattering,atmospheric absorption,fading,and especially penetration losses compared to the existing sub-6 GHz frequency band.Then,it is fundamental to optimize the mmWave band propagation channel to facilitate the practical 5G implementation for the network operators.Therefore,this study intends to investigate the outdoor channel characteristics of 26,28,36,and 38 GHz frequency bands for the communication infrastructure at the building to the ground floor in both Line of Sight(LOS)and Non-Line of Sight(NLOS)environments.The experimental campaign has studied the propagation path loss models such as Floating-Intercept(FI)and Close-In(CI)for the building to ground floor environment in LOS and NLOS scenarios.The findings obtained from the field experiments clearly show that the CI propagation model delivers much better performance in comparison with the FI model,thanks to its simple setup,accuracy,and precise function. 展开更多
关键词 5G mmWave propagation channel path loss channel characterization field experiment
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Uncertainty aversion and farmers' innovative seed adoption:Evidence from a field experiment in rural China
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作者 WU Hai-xia SONG Yan +1 位作者 YU Le-shan GE Yan 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2023年第6期1928-1944,共17页
Based on the microdata of 705 wheat farmers in the Loess Plateau, this study empirically analyzes the impact of uncertainty on farmers' adoption of innovative seeds using a field experiment. The results indicate t... Based on the microdata of 705 wheat farmers in the Loess Plateau, this study empirically analyzes the impact of uncertainty on farmers' adoption of innovative seeds using a field experiment. The results indicate that farmers are generally ambiguity-averse and risk-averse. In addition, farmers with higher ambiguity aversion and risk aversion are less likely to adopt innovative wheat seeds, where their risk aversion plays a dominant role. Enhancing information access will alleviate the negative influence of ambiguity aversion on farmers' adoption of innovative seeds, and interlinked insurance and credit contracts will be beneficial to ease the adverse effect of risk aversion on the adoption of innovative wheat seeds. Meanwhile, heterogeneity analysis reveals that the inhibitory effects of ambiguity aversion and risk aversion on innovative seed adoption are more significant among farmers with lower education and household income.The government can establish both ex-ante and ex-post relevant guarantee mechanisms to help farmers preferably cope with various uncertainties in the production process, remitting farmers' ambiguity aversion and risk aversion to enhance new agricultural technology adoption rates. 展开更多
关键词 ambiguity aversion risk aversion technology adoption field experiment
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Influence of magnetic field on power deposition in high magnetic field helicon experiment
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作者 周岩 季佩宇 +2 位作者 李茂洋 诸葛兰剑 吴雪梅 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第2期379-384,共6页
Based on high magnetic field helicon experiment(HMHX), HELIC code was used to study the effect of different magnetic fields on the power deposition under parabolic distribution. This paper is divided into three parts:... Based on high magnetic field helicon experiment(HMHX), HELIC code was used to study the effect of different magnetic fields on the power deposition under parabolic distribution. This paper is divided into three parts: preliminary calculation, actual discharge experiment and calculation. The results of preliminary calculation show that a magnetic field that is too small or too large cannot produce a good power deposition effect. When the magnetic field strength is 1200 Gs,a better power deposition can be obtained. The actual discharge experiment illustrates that the change of the magnetic field will have a certain influence on the discharge phenomenon. Finally, the results of verification calculation successfully verify the accuracy of the results of preliminary simulation. The results show that in the actual discharge experiment, it can achieve the best deposition effect when the magnetic field is 1185 Gs. 展开更多
关键词 high magnetic field helicon experiment(HMHX) HELIC code magnetic field power deposition
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The Effect of Three New Fungicides against Rice Sheath Blight in Field Experiment 被引量:1
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作者 李宁 殷徽 常海滨 《Agricultural Science & Technology》 CAS 2015年第3期551-552,577,共3页
[Objective] The aim was to study the effect of three new fungicides against rice sheath blight in field experiment. [Methods] The experiment set up 7 treatments with three times of repetition and designed by random gr... [Objective] The aim was to study the effect of three new fungicides against rice sheath blight in field experiment. [Methods] The experiment set up 7 treatments with three times of repetition and designed by random grouping. By using 5 sampling points in each plot, and investigating continuous 4 holes of each point, total plants, diseased plants and disease degrees were recorded. Then disease index and control efficiency were calculated, and variance analysis was carried out. [Results] 300 or 450 ml/hm^2 azoxystrobin + difenoconazole 325 g/L SC had better control efficiency to rice sheath blight and had no phytotoxicity effect, we should use it at the initial disease stage and continuously spray 2-3 times. [Conclusion] The experiment provided a theoretical basis for controlling rice sheath blight using fungicides. 展开更多
关键词 Rice sheath blight Fungicides field experiment
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Research on High Precision Borehole Temperature Measurement Technology
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作者 ZHANG Bing ZHU Xiaoyi +7 位作者 WANG Xiaolei XING Lili XUE Bing LI Jiang GAO Shanghua SU Peng WANG Yuru WANG Chuhan 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2024年第S01期81-83,共3页
From 2019 to 2021,China Seismic Experimental Site has built twelve 300 m deep well multi-measurement comprehensive observation stations in the cross-fault area of the Aninghe-Zemuhe fault zone,integrating BBVS120 very... From 2019 to 2021,China Seismic Experimental Site has built twelve 300 m deep well multi-measurement comprehensive observation stations in the cross-fault area of the Aninghe-Zemuhe fault zone,integrating BBVS120 very broadband borehole seismometer,RZB four-gauge borehole strainmeter and geothermometer with resolution up to 0.0001℃.The borehole diameter is 150 mm and the inner diameter of the sleeve is 130 mm.The multi-item integrated observation system is divided into two parts:underground and surface.The downhole part is mainly composed of sensor and power supply signal isolation. 展开更多
关键词 high-precision borehole thermometer downhole integrated observation seismic science experiment field
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Effects of Long-Term Organic Amendments on Soil Organic Carbon in a Paddy Field: A Case Study on Red Soil 被引量:9
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作者 HUANG Qing-hai LI Da-ming +8 位作者 LIU Kai-lou YU Xi-chu YE Hui-cai HU Hui-wen XU Xiao-lin WANG Sai-lian ZHOU Li-jun DUAN Ying-hua ZHANG Wen-ju 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2014年第3期570-576,共7页
Soil organic carbon (SOC) is one of the main carbon reservoirs in the terrestrial ecosystem. It is important to study SOC dynamics and effects of organic carbon amendments in paddy fields because of their vest expan... Soil organic carbon (SOC) is one of the main carbon reservoirs in the terrestrial ecosystem. It is important to study SOC dynamics and effects of organic carbon amendments in paddy fields because of their vest expansion in south China. A study was carried out to evaluate the relationship between the SOC content and organic carbon input under various organic amendments at a long-term fertilization experiment that was established on a red soil under a double rice cropping system in 1981. The treatments included non-fertilization (CK), nitrogen-phosphorus-potassium fertilization in early rice only (NPK), green manure (Astragalus sinicus L.) in early rice only (OM1), high rate of green manure in early rice only (OM2), combined green manure in early rice and farmyard manure in late rice (OM3), combined green manure in early rice, farmyard manure in late rice and rice straw mulching in winter (OM4), combined green manure in early rice and rice straw mulching in winter (OMS). Our data showed that the SOC content was the highest under OM3 and OM4, followed by OM1, OM2 and OM5, then NPK fertilization, and the lowest under non-fertilization. However, our analyses in SOC stock indicated a significant difference between OM3 (33.9 t ha^-1) and OM4 (31.8 t ha^-1), but no difference between NPK fertilization (27 t ha^-1) and nonfertilization (28.1 t ha^-1). There was a significant linear increase in SOC over time for all treatments, and the slop of linear equation was greater in organic manure treatments (0.276-0.344 g kg-1 yr^-1) than in chemical fertilizer (0.216 g kg^-1 yr^-1) and no fertilizer (0.127 g kg^-1 yr^-1). 展开更多
关键词 long-term field experiment organic amendments soil organic carbon paddy soil derived from red earth
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Optimal design of vegetation in residential district with numerical simulation and field experiment 被引量:5
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作者 洪波 林波荣 +1 位作者 王冰 李树华 《Journal of Central South University》 SCIE EI CAS 2012年第3期688-695,共8页
Vegetation plays a key role in improving wind environment of residential districts,and is helpful for creating a comfortable and beautiful living environment.The optimal design of vegetation for wind environment impro... Vegetation plays a key role in improving wind environment of residential districts,and is helpful for creating a comfortable and beautiful living environment.The optimal design of vegetation for wind environment improvement in winter was investigated by carrying out field experiments in Heqingyuan residential area in Beijing,and after that,numerical simulation with SPOTE(simulation platform for outdoor thermal environment) experiments for outdoor thermal environment of vegetation was adopted for comparison.The conclusions were summarized as follows:1) By comparing the experimental data with simulation results,it could be concluded that the wind field simulated was consistent with the actual wind field,and the flow distribution impacted by vegetation could be accurately reflected;2) The wind velocity with vegetation was lower than that without vegetation,and the wind velocity was reduced by 46%;3) By adjusting arrangement and types of vegetation in the regions with excessively large wind velocity,the pedestrian-level wind velocity could be obviously improved through the simulation and comparison. 展开更多
关键词 wind environment simulation platform for outdoor thermal environment (SPOTE) field experiment optimal design of vegetation SIMULATION
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Field experiment of rainfall infiltration on a soil slope and simulations based on a water-air two-phase flow model 被引量:2
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作者 LIU Gang ZHA Xin-yuan +1 位作者 GUAN Jin-kun TONG Fu-guo 《Journal of Mountain Science》 SCIE CSCD 2021年第8期2159-2167,共9页
Rainfall infiltration on a soil slope is usually an unsaturated seepage process that can be described by a water-air two-phase flow model.The effect of pore air pressure on rainfall infiltration has been widely recogn... Rainfall infiltration on a soil slope is usually an unsaturated seepage process that can be described by a water-air two-phase flow model.The effect of pore air pressure on rainfall infiltration has been widely recognized and validated by means of numerical simulations and laboratory experiments.However,whether a slope can actually seal pore air continues to be debated by researchers.In this study,a water-air two-phase flow model is used to simulate the rainfall infiltration process on a soil slope,and a field experiment is conducted to realistically test the sealing conditions of a slope.According to the numerical simulation,the areas of water and air flow in and out on the slope surface are relatively stable and can be classified as the“inhalation zone”and“overflow zone”,respectively.Intermittent rainfall on the soil slope has an amplifying effect on pore air pressure because rainfall intensity is usually at the millimeter level,and it causes pore air pressure to reach the cm level.A field experiment was performed to determine whether a slope can realistically seal pore air and subsequently verify the regularity of rainfall infiltration.Air pressure sensors were buried in the slope to monitor the pore air pressures during the rainfall process.The monitoring results show that the pore air pressure in the slope changed,which indicates that the slope can seal air.Moreover,the amplification effects of intermittent rainfall on pore air pressure were observed for natural rainfall,which agrees well with the numerical simulation results. 展开更多
关键词 Rainfall infiltration Runoff regularity field experiment Water-air two-phase flow
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Evaluation of a Micro-scale Wind Model's Performance over Realistic Building Clusters Using Wind Tunnel Experiments 被引量:3
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作者 Ning ZHANG Yunsong DU +1 位作者 Shiguang MIAO Xiaoyi FANG 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2016年第8期969-978,共10页
The simulation performance over complex building clusters of a wind simulation model(Wind Information Field Fast Analysis model, WIFFA) in a micro-scale air pollutant dispersion model system(Urban Microscale Air Po... The simulation performance over complex building clusters of a wind simulation model(Wind Information Field Fast Analysis model, WIFFA) in a micro-scale air pollutant dispersion model system(Urban Microscale Air Pollution dispersion Simulation model, UMAPS) is evaluated using various wind tunnel experimental data including the CEDVAL(Compilation of Experimental Data for Validation of Micro-Scale Dispersion Models) wind tunnel experiment data and the NJU-FZ experiment data(Nanjing University-Fang Zhuang neighborhood wind tunnel experiment data). The results show that the wind model can reproduce the vortexes triggered by urban buildings well, and the flow patterns in urban street canyons and building clusters can also be represented. Due to the complex shapes of buildings and their distributions, the simulation deviations/discrepancies from the measurements are usually caused by the simplification of the building shapes and the determination of the key zone sizes. The computational efficiencies of different cases are also discussed in this paper. The model has a high computational efficiency compared to traditional numerical models that solve the Navier–Stokes equations, and can produce very high-resolution(1–5 m) wind fields of a complex neighborhood scale urban building canopy(~ 1 km ×1km) in less than 3 min when run on a personal computer. 展开更多
关键词 numerical model urban wind field wind tunnel experiment data emergency response model
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Monthly gravity field solution from GRACE range measurements using modified short arc approach 被引量:4
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作者 Shen Yunzhong Chen Qiujie Xu Houze 《Geodesy and Geodynamics》 2015年第4期261-266,共6页
In this paper we present a series of monthly gravity field solutions from Gravity Recovery and Climate Experiment(GRACE) range measurements using modified short arc approach,in which the ambiguity of range measureme... In this paper we present a series of monthly gravity field solutions from Gravity Recovery and Climate Experiment(GRACE) range measurements using modified short arc approach,in which the ambiguity of range measurements is eliminated via differentiating two adjacent range measurements.The data used for developing our monthly gravity field model are same as Tongji-GRACEOl model except that the range measurements are used to replace the range rate measurements,and our model is truncated to degree and order 60,spanning Jan.2004 to Dec.2010 also same as Tongji-GRACE01 model.Based on the comparison results of the C_(2,0),C_(2,1),S_(2,1),and C_(15,15),S_(15,15),time series and the global mass change signals as well as the mass change time series in Amazon area of our model with those of Tongji-GRACE01 model,we can conclude that our monthly gravity field model is comparable with Tongji-GRACE01 monthly model. 展开更多
关键词 Satellite geodesy Gravity field model Time-variable gravity field Gravity satellite Gravity Recovery and Climate Experiment (GRACE)Short arc approach Range data Mass change Tongji-GRACE01
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WHU-Grace01s:A new temporal gravity field model recovered from GRACE KBRR data alone 被引量:2
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作者 Zhou Hao Luo Zhicai Zhong Bo 《Geodesy and Geodynamics》 2015年第5期316-323,共8页
A new temporal gravity field model called WHU-Grace01s solely recovered from Gravity Recovery and Climate Experiment (GRACE) K-Band Range Rate (KBRR) data based on dynamic integral approach is presented in this pa... A new temporal gravity field model called WHU-Grace01s solely recovered from Gravity Recovery and Climate Experiment (GRACE) K-Band Range Rate (KBRR) data based on dynamic integral approach is presented in this paper. After meticulously preprocessing of the GRACE KBRR data, the root mean square of its post residuals is about 0.2 micrometers per second, and seventy-two monthly temporal solutions truncated to degree and order 60 are computed for the period from January 2003 to December 2008. After applying the combi- nation filter in WHU-Grace01s, the global temporal signals show obvious periodical change rules in the large-scale fiver basins. In terms of the degree variance, our solution is smaller at high degrees, and shows a good consistency at the rest of degrees with the Release 05 models from Center for Space Research (CSR), GeoForschungsZentrum Potsdam (GFZ) and Jet Pro- pulsion Laboratory 0PL). Compared with other published models in terms of equivalent water height distribution, our solution is consistent with those published by CSR, GFZ, JPL, Delft institute of Earth Observation and Space system (DEOS), Tongji University (Tongji), Institute of Theoretical Geodesy (ITG), Astronomical Institute in University of Bern (AIUB) and Groupe de Recherche de Geodesie Spatiale (GRGS}, which indicates that the accuracy of WHU-Grace01s has a good consistency with the previously published GRACE solutions. 展开更多
关键词 Temporal gravity field model Gravity Recovery and Climate Experiment (GRACE) Dynamic integral approach K-Band Range Rate (KBRR) Satellite gravity Spherical harmonics Equivalent water height Geopotential determination
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The idea and project of the “Medium-Scale Experiment Field for Earthquake Prediction”──Research on observations and applications of mining earthquake in Mentougou Coal Mine
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作者 张少泉 任振启 +2 位作者 张连城 张建军 邹立晔 《Acta Seismologica Sinica(English Edition)》 CSCD 1996年第4期142-146,148-150+152-,共10页
A brief account of the development of the research on mining earthquakes and the general situation of the Mentougou Coal Mine medium scale experiment field for earthquake prediction and the project of monitor and p... A brief account of the development of the research on mining earthquakes and the general situation of the Mentougou Coal Mine medium scale experiment field for earthquake prediction and the project of monitor and prediction is given. The differences of waveforms between mining earthquakes and natural earthquakes is discussed. The magnitude frequency distribution of the 79 000 mining earthquakes of over M L1.0 from 1984 to 1995 is summarized . Finally, taking PH and PV, the principal compressive stress components of the focal mechanism of the mining earthquakes, as the criteria, analyses the stress background of the 12 large mining earthquakes. 展开更多
关键词 mining earthquakes mining seismology earthquake prediction Mentougou Coal Mine medium scale experiment field for earthquake prediction.
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Do Aid Donors Plant the Grassroots? Evidence from a Randomized Field Experiment in the US and Uganda
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作者 Danny Walker 《International Relations and Diplomacy》 2015年第3期192-208,共17页
Recent literature dealing with nongovemmental organizations (NGOs) claims that NGOs have little incentive to base their decisions and strategies on local needs and instead are governed largely by their current and p... Recent literature dealing with nongovemmental organizations (NGOs) claims that NGOs have little incentive to base their decisions and strategies on local needs and instead are governed largely by their current and prospective donors (McGann & Johnstone, 2006; Prakash & Gugerty, 2010; Bollen et al., 2005). To test this claim, I have created a quantitative experiment in the US and Uganda in which organizations were randomly assigned to a control group or one of four treatment groups based on the main stakeholders of the NGO market---donors, local government officials, project beneficiaries, and NGO peers. In each group, organizations were invited to take a survey and were told that the results of their survey would be published to one of these four stakeholder groups. Thus, differences in response rates between groups are attributed to differences in the degree of concern that NGOs felt about the opinions of a given stakeholder. I hypothesized that NGOs care more about the opinions of their donors than other stakeholder groups and found support for this hypothesis among NGOs in the US. 展开更多
关键词 Nongovernmental organizations field experiments aid accountability Uganda
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Ebola Response in Liberia;Field Experiences, Challenges and Lessons Learnt during the Response, 2014-2015
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作者 Mutaawe Lubogo Donewell Bangure +6 位作者 Justin Maeda Sasita Shabani Theophile C. Malibiche Herilinda Temba Lucas Godbless Naod Bruhan Oketta Julius 《Open Journal of Epidemiology》 2016年第1期88-94,共7页
The 2014-2015 Ebola Virus Disease (EVD) outbreaks which began in Guinea and later spread to Liberia, Sierra Leona and other countries have been responsible for a number of infections and deaths among the communities i... The 2014-2015 Ebola Virus Disease (EVD) outbreaks which began in Guinea and later spread to Liberia, Sierra Leona and other countries have been responsible for a number of infections and deaths among the communities including health workers. The natural host of the EVD virus has not been identified even when scientific evidence points to bats as the natural reservoirs to similar strains of EVD virus. EVD male survivors have also been identified as a potential source of infection among the populations. Some of the reasons attributed to this rapid spread of EVD to other countries have been weak early warning systems to identify and notify health authorities of such diseases of high epidemic potential. Liberia has been one of the countries to be declared EVD free on two different occasions in 2015 each with a different epicenter. Despite a number of international organizations coming together to support control efforts in Liberia, the coordination of response activities by the Ministry of Health and Social Welfare and replicated at all levels of the surveillance systems was the key in suppressing the outbreak. Adoption of the Integrated Disease Surveillance and Response (IDSR) guidelines as recommended by World Health Organization (WHO/AFRO) was a positive step towards the structuring of response activities. Capacity building of health workers in infection control and prevention and surveillance was important to improve skills of health workers to triage EVD cases as recommended by WHO. Training community health volunteers in contact tracing and active case search was important in strengthening the Early Warning Disease surveillance system. Decentralization of response activities in addition to establishing Ebola Treatment units and Community Care Centers in all counties was vital in containing the spread of infection. Even when EVD was associated to high levels of stigma, community and individual counseling sessions led by community leaders enabled building community trust to refer cases for treatment. The EVD survivors distributed in different parts of the country are potential sources of new EVD infections. This will require strengthening early warning systems and response capacity at all levels. 展开更多
关键词 EBOLA LIBERIA field Experiences CHALLENGES
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Optimization of reverse circulation bit based on field experiment
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作者 Hong REN Kun YIN Kun BO 《Global Geology》 2008年第1期47-51,共5页
By field experiment in Sandaozhuang W-Mo mining area in Luanchuan of Henan Province, the authors analyzed the Experimental result of reverse circulation bit on the basis of different structures and obtained the follow... By field experiment in Sandaozhuang W-Mo mining area in Luanchuan of Henan Province, the authors analyzed the Experimental result of reverse circulation bit on the basis of different structures and obtained the following conclusion: the design parameter of reverse circulation bit, the number, diameter and angle of the spurt hole can influence on the reverse circulation effect. The bit with inner spurt hole is better obviously than that one without inner spurt hole in reverse circulation, one or two right and the best choice of inner spurt hole is that the diameter is Φ8, the angle is 30° dip up and the suitable number is two to three. 展开更多
关键词 field experiment reverse circulation bit STRUCTURE spurt hole
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Outside the Backdoor:Entrepreneurship,Field Experience and Preservice Teachers
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作者 Dia Gary 《Journal of International Education and Practice》 2022年第2期1-9,共9页
This research is to share qualitative data of one preservice teacher,and one early childhood entrepreneur,who educated young children in an exclusive outdoor preschool.The study was conducted in a rural community wher... This research is to share qualitative data of one preservice teacher,and one early childhood entrepreneur,who educated young children in an exclusive outdoor preschool.The study was conducted in a rural community where most preschools were held in the traditional venue-inside.The Coronavirus-19 pandemic presented many obstacles to the placement of preservice teachers in an appropriate early childhood setting.The university discouraged all direct contact with children.Instead,preservice teachers were expected to view videos of veteran teachers,who in former years,submitted teaching videos to obtain a“National Boards Certification.”The objective was that the preservice teachers would“reflect”and learn from the electronic source.This electronic substitution was unacceptable to the researcher.Practicum experiences allow for rich collaboration between preservice teacher and child.Electronic sources can never replicate the rich learning that happens during an authentic face-to face encounter with a child.Thus,the vision for the study was born.As an alternative to exclusive electronic learning,the preservice university supervisor initiated the opportunity for preservice teachers to participate with a local entrepreneur who was in the process of designing and implementing an exclusive outdoor school.Nature and environmental field experience opportunities for preservice teachers are promising alternatives to the traditional preschool setting.Venues that encourage nature and environmental studies enhance early childhood programs and create opportunities for preservice teachers,and the children they serve,to appreciate the nature around them enhancing their natural curiosity and investigative skills to seek,study,and share.This research article shares the reflections of both the preschool entrepreneur as well as the preservice teacher.It is a pragmatic description of how the exclusive outdoor environment is feasible and presents the challenges and assets that the environmental venue provides. 展开更多
关键词 Outdoor School Higher education field experience Preservice teachers ENTREPRENEURSHIP
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