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2019

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Articles 1141 - 1170 of 1657

Full-Text Articles in Earth Sciences

The Characteristics Of Organic Matter In Coal-Measure Source Rocks And Coal-Measure Gas Resource Potential In Eastern Henan Province, Yang Yanqing, Zhang Xiaodong, Xu Yakun, Zhang Peng, Wang Kun, Zhu Chunhui Feb 2019

The Characteristics Of Organic Matter In Coal-Measure Source Rocks And Coal-Measure Gas Resource Potential In Eastern Henan Province, Yang Yanqing, Zhang Xiaodong, Xu Yakun, Zhang Peng, Wang Kun, Zhu Chunhui

Coal Geology & Exploration

In order to evaluate the hydrocarbon generation potential of coal-measure source rocks in eastern Henan Province, based on the measurement results of organic carbon content, vitrinite reflectance and the identification of maceral and type of kerogen in source rocks, the organic geochemical characteristics and the resource potential of coal-measure gas in different blocks of eastern Henan Province were comprehensively analyzed, and favorable blocks for coal-measure gas exploration were designated. The results show that the organic carbon mass fraction of coal-measure source rocks presents low as a whole(less than 1.5%). Kerogen in coal-measures source rocks is mainly of type Ⅲ and …

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Analysis Of Water Abundance Characteristics Of Sandstone Aquifer In Luohe Formation On The Basis Of Arcgis, Hou Enke, Long Tianwen, Liu Qingli, Wang Fei, Fan Zhigang Feb 2019

Analysis Of Water Abundance Characteristics Of Sandstone Aquifer In Luohe Formation On The Basis Of Arcgis, Hou Enke, Long Tianwen, Liu Qingli, Wang Fei, Fan Zhigang

Coal Geology & Exploration

Aquifer water abundance evaluation is the prerequisite for coalmine water inflow prediction and water disaster prevention. Luohe aquifer is the roof of No.4 coal seam on panel 41 in Wenjiapo mine. Six main controlling factors of Luohe aquifer chosen to assess coal water abundance are aquifer thickness, porosity, moisture content, washing liquid consumption and apparent resistivity of upper and lower Luohe Formation. Analytic hierarchy process(AHP) has been used to determine the weight of each control factor. Based on ArcGIS numerical visualization platform, the vector maps of factors are normalized and superimposed, and then water abundance evaluation model of aquifer based …

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Fuzzy Random Optimization Of Generalized Kelvin Constitutive Model For Creep Of Artificial Freezing Clay, Yao Yafeng, Cheng Hua, Rong Chuanxin, Zhang Nan, Lin Jian Feb 2019

Fuzzy Random Optimization Of Generalized Kelvin Constitutive Model For Creep Of Artificial Freezing Clay, Yao Yafeng, Cheng Hua, Rong Chuanxin, Zhang Nan, Lin Jian

Coal Geology & Exploration

The constitutive model of freezing creep is one of the important reference data for shaft building using freezing method. Uniaxial creep tests under different stress levels were conducted for the artificial freezing clay at -5℃, -10℃, -15℃ and -20℃. So the changing rules of creep curves were obtained under the condition of different temperatures and different stress levels. On this basis, traditional Guess-Newton algorithm has been improved by fuzzy random iterative search and the of the fuzzy random Guess-Newton algorithm steps were obtained, then we use the improved algorithm to optimize the parameters of the generalized Kelvin constructive model, obtained …

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Clgis Logging Data Format Conversion, Lin Jiamin, Zhang Gong Feb 2019

Clgis Logging Data Format Conversion, Lin Jiamin, Zhang Gong

Coal Geology & Exploration

In order to solve the problem of DAT log data format conversion, well logging data of CLGIS(Coalfield Logging Geology Interpretation System) is analyzed in detail. On the basis of analysis of the data storage format, format conversion program is written. The program can accurately convert the DAT format data to LAS format data promptly. The LAS format data can be loaded into the commonly used well logging software in oil field easily. With the help of powerful software, the drawing efficiency and quality of coalfield well logging is greatly improved.

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Mechanical Characteristics And Test Of Rotary Drilling Of Pdc Anchor Bit, Zhang Youzhen, Zhang Ning, Zhang Xianzhen Feb 2019

Mechanical Characteristics And Test Of Rotary Drilling Of Pdc Anchor Bit, Zhang Youzhen, Zhang Ning, Zhang Xianzhen

Coal Geology & Exploration

For the construction requirements of the fast and accurate drilling of anchor hole in a coal roadway, the main mechanical factors are analyzed in theory through the establishment of PDC anchor bit rotary drilling mechanics model. The results show that the axial force of the PDC cutting tooth increases with the increase of the penetration depth, and shows the trend of first decreasing and then increasing with the increase of the cutting angle. When the friction coefficient of the coal-bearing strata is 0.20 to 0.43, the optimum cutting angle is from 15.0° to 18.3°, and the axial force and the …

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Progress In The Research On Drilling Technology And Equipment In Coal Mining Areas Of China, Li Quanxin, Shi Zhijun, Tian Hongliang, Yao Ke, Liu Jianlin, Yao Yafeng, Xu Chao, Fang Jun, Liu Fei Feb 2019

Progress In The Research On Drilling Technology And Equipment In Coal Mining Areas Of China, Li Quanxin, Shi Zhijun, Tian Hongliang, Yao Ke, Liu Jianlin, Yao Yafeng, Xu Chao, Fang Jun, Liu Fei

Coal Geology & Exploration

Drilling technology and equipment play a key role in coalbed methane(gas) development and ensuring coal mine safe production in coal mining areas. The complicated geological and mining conditions of coal seams in China determine that the drilling technology and equipment must be based on the basic situation of coal mining areas and take the way of independent innovation. The representative achievements of drilling technology and equipment in coal mining area during the Eleventh Five-Year Plan and the Twelfth Five-Year Plan were systematically summarized in this paper. Additionally, it presents comprehensive introduction to the great achievements of surface drilling and underground …

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Design Of Parameter Monitoring Software For Full Hydraulic Drilling Rig Based On Embedded Technology, Liao Jiangnan, Jiang Nan, Song Haitao, Dong Hongbo, Ma Bin Feb 2019

Design Of Parameter Monitoring Software For Full Hydraulic Drilling Rig Based On Embedded Technology, Liao Jiangnan, Jiang Nan, Song Haitao, Dong Hongbo, Ma Bin

Coal Geology & Exploration

In order to reduce the development cost of the coal mine hydraulic drilling rig monitoring and diagnosis system, realize the versatility and portability of the monitoring and diagnosis system, and simplify the operation process, an embedded parameter monitoring software for the domestic mainstream full hydraulic drilling rig was designed. The software took STM32F407 microprocessor as the running environment and was developed in the environment of Visual Studio 2013 with C language. After completing GUI simulation on emWin Simulation, the software function verification experiment was carried out on the ZDY4000LR drilling rig. The experiment shows that the software ran stably and …

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Design Of Remote Control System Of Drilling Rig In Coal Mines, Weng Yinsheng, Wu Di, Lu Feifei, Wang Longpeng Feb 2019

Design Of Remote Control System Of Drilling Rig In Coal Mines, Weng Yinsheng, Wu Di, Lu Feifei, Wang Longpeng

Coal Geology & Exploration

In order to solve the influence of the dangerous conditions in the deep mine, such as large percus-sive ground pressure and high temperature and humidity of the roadways in deep mines on drilling operation, a remote control drilling rig control system is designed. The control system consists of local control terminal and remote control terminal, both communicating by CAN(Controller Area Network) bus and optical fiber for data and image. Local control terminal core uses automobile PLC(Programmable Logic Controller) as the control core to realize data acquisition and control, develops program in CoDeSys. The remote control terminal, based on MCU and …

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Trajectory Design Of Oblique Section In Nearly Horizontal Directional Hole In Inclined Formation In Underground Coal Mine, Zhang Yingjie, Zhao Yongzhe, Yang Zhong, Mo Haitao Feb 2019

Trajectory Design Of Oblique Section In Nearly Horizontal Directional Hole In Inclined Formation In Underground Coal Mine, Zhang Yingjie, Zhao Yongzhe, Yang Zhong, Mo Haitao

Coal Geology & Exploration

Trajectory design of the near-horizontal directional drilling technology in underground coal mine is one of key aspects to successfully implement the technology. The trajectory of hole in a nearly horizontal formation is designed generally by two-dimensional method, and this method usually leads to the problem that the deflecting section of the hole travels out of the inclined target formation.Therefor, the calculation methods of the drilled formation true thickness were studied in the paper, the method using the unit normal vector of formation was proposed, and computation table in Excel was developed to guide trajectory design of near-horizontal directional drilling. The …

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Geological Consideration For Site Selection Of Underground Coal Gasifier, Han Lei, Qin Yong, Wang Zuotang Feb 2019

Geological Consideration For Site Selection Of Underground Coal Gasifier, Han Lei, Qin Yong, Wang Zuotang

Coal Geology & Exploration

Underground coal gasification(UCG) is a revolution in traditional coal mining technology, and the site selection of underground coal gasifier is a prerequisite for a successful UCG project. Refining and analyzing the previous research results, the principle of UCG and the geological controls of site selection of underground coal gasifier were reviewed. The results show that lignite is the most suitable for UCG. UCG should choose thickness greater than 2 m, angle is less than 70° and buried depth of coal seam is 300 to 2 000 meters. At the same time, the UCG process may pollute the groundwater, and the …

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Fracture Extension Law Of Hydraulic Fracture In Coal With Different Structure, Jia Qifeng, Ni Xiaoming, Zhao Yongchao, Cao Yunxing Feb 2019

Fracture Extension Law Of Hydraulic Fracture In Coal With Different Structure, Jia Qifeng, Ni Xiaoming, Zhao Yongchao, Cao Yunxing

Coal Geology & Exploration

To find out the fracture extension law of coal hydraulic fracturing with different coal body structures can lay a foundation for reasonable well pattern deployment. Taking Shizhuang block of Qinshui basin as the research object, the fracture of coal core was observed, and four kinds of coal with fracture development degree were divided. Based on the theory of rock mass mechanics, the stress field calculation model of fracture tip and the judgment criterion of whether hydraulic fracture can pass through natural fracture in hydraulic fracturing process were established. According to the measured data of CBM wells, the reliability of theoretical …

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Study On Pore Structure And Pressure-Sensitive Effect Of Tectonic Coal In Huaibei Xutuan Mine, Dong Kui, Jia Jiancheng, Gong Zewen, Wu Yan Feb 2019

Study On Pore Structure And Pressure-Sensitive Effect Of Tectonic Coal In Huaibei Xutuan Mine, Dong Kui, Jia Jiancheng, Gong Zewen, Wu Yan

Coal Geology & Exploration

In order to discuss pore structure and pressure-sensitive effect of tectonic coal, coal samples of Huaibei Xutuan mine were measured by optical microscope, scanning electron microscope, mercury injection, and triaxial servo-controlled seepage equipment for thermo-fluid-solid coupling to reveal the pore structure and the influence of effective stress on permeability or permeability coefficient of structural coal. The results show that cataclastic structure of tectonic coal is regular, flat and has good connectivity; the pores of primary coal are mainly composed of micropores, micropores and transitional pores are dominant in tectonic coal has. The effective stress of ductile deformed coal has a …

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Preparation Of Polished Slice Of Special Coal And Its Influence On Coal Petrology Analysis, Liu Shande Feb 2019

Preparation Of Polished Slice Of Special Coal And Its Influence On Coal Petrology Analysis, Liu Shande

Coal Geology & Exploration

Coal petrology analysis is widely used in coal facies research, geological exploration and coal blending test. Qualified polished coal slice is the premise of coal petrology analysis. In order to solve the preparation problem of special coal optical plates, such as brittle samples and aging coal optical plates, a complete preparation process was raised, and the feasibility of the process was verified. The results showed that Rmax was very little affected by secondary preparation, but the maceral group composition content was significantly affected, and the fluctuation of the anthracite' microcomponent was the greatest. When the maceral group composition quantification …

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Reservoir-Forming Conditions Of Shale Gas In Badaowan Formation In Fukang Area, Xinjiang, Zhang Min, Li Xianqing, Zhang Jizhen, Sun Jie, Liang Wanle, Duan Zhiyou, Li Hanqing Feb 2019

Reservoir-Forming Conditions Of Shale Gas In Badaowan Formation In Fukang Area, Xinjiang, Zhang Min, Li Xianqing, Zhang Jizhen, Sun Jie, Liang Wanle, Duan Zhiyou, Li Hanqing

Coal Geology & Exploration

In order to evaluate the potential of shale gas of coal measures in Fukang area, Xinjiang, taking the shale of Jurassic coal measures in Badaowan Formation as an example, the study was carried out and the favorable accumulation area for shale gas was preliminarily put forward according to the drilling, core data and sample analysis results in this paper. The result shows that the accumulative thickness of Jurassic Badaowan Formation shale is big(200-400 m), the buried depth is shallow(<1 500 m), the organic carbon content is high(average TOC>2.0%), mainly of type Ⅲ and Ⅱ2, thermal evolution level is moderate(Rran is 0.8%-1.1%, mature), physical property of reservoir …

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Modification Of Na-K-Mg Triangular Diagram And Selection Of Na-K Geothermometer, Wang Xin, Qi Jihong, Xu Mo, Ma Xiaoyun Feb 2019

Modification Of Na-K-Mg Triangular Diagram And Selection Of Na-K Geothermometer, Wang Xin, Qi Jihong, Xu Mo, Ma Xiaoyun

Coal Geology & Exploration

Na-K-Mg triangular diagram is a preliminary method of determining the water-rock equilibrium state. It does not specifically consider the effect of geothermometer equations and mineral compositions on the equilibrium state. Therefore, using the Na-K-Mg triangular diagram modified by different Na-K geothermometer equations to judge water-rock equilibrium state, and using the suitable Na-K geothermometer equation to calculate the temperature of geothermal reservoirs, is of great significance to divide the genetic types of geothermal systems and develop or utilize geothermal resources. It is found that any point in the modified Na-K-Mg triangular diagram is fully equilibrated with the curve determined by one …

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Characteristics Of Height Of Water Flowing Fractured Zone Caused During Ful-Ly-Mechanized Caving Mining In Huanglong Coalfield, Li Chaofeng Feb 2019

Characteristics Of Height Of Water Flowing Fractured Zone Caused During Ful-Ly-Mechanized Caving Mining In Huanglong Coalfield, Li Chaofeng

Coal Geology & Exploration

In order to study the law of height of water flowing fractured zone caused by fully-mechanized caving mining in Huanglong coalfield, this paper has systematically collected the measured data in the region, and methods of mathematical statistics and regression analysis were used to study the relationship among the height of water flowing fractured zone, width of working face, depth of coal seam and height of coal mining. The results show that:When the width of working face was less than 240 m and the height of coal mining was 8.5 to 9.5 m, the height of water flowing fractured zone under …

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Coal Mine Water Inrush Prediction Based On Lstm Neural Network, Dong Lili, Fei Cheng, Zhang Xiang, Cao Chaofan Feb 2019

Coal Mine Water Inrush Prediction Based On Lstm Neural Network, Dong Lili, Fei Cheng, Zhang Xiang, Cao Chaofan

Coal Geology & Exploration

According to the prediction of water inrush from coal seam floor, based on the summarization of existing water inrush prediction methods and theories, the feature selection experiment shows that water pressure, distance from the working surface, sandstone section thickness, coal thickness, coal seam inclination, fault throw, fissure zone, mining area, mining height and strike length are the main factors affecting the occurrence of water inrush. These factors are complex and non-linear. A water inrush prediction model based on long short-term memory(LSTM) neural network was proposed. The data of the coal mine water inrush case was used as sample data to …

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Influence Of Composite Roof Structure On The Stability Of Coal Roadway, Chen Xinnian, Wang Jingchun, Xiong Xianyu, Fan Jiawei, Shen Pan Feb 2019

Influence Of Composite Roof Structure On The Stability Of Coal Roadway, Chen Xinnian, Wang Jingchun, Xiong Xianyu, Fan Jiawei, Shen Pan

Coal Geology & Exploration

The composite roof structure of coal roadway is rather complex. Its stability is related to lithology, thickness of strata, number of strata, location of strata and cohesive force between layers. Based on mechanics theory of simplified composite roof composite beams, a simplified mechanical test model of composite beams was established, and the effects of the structural characteristics of composite roof on the stability of composite beams were analyzed by experiments. The purpose is to provide a scientific basis for the classification and control of composite roof stability. The results show that the stability of the roof increases with the increase …

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Numerical Analysis Of Temperature Field Of Underwater Dredging Artificial Frozen Plate, Wu Yuwei, Hu Jun, Wang Zhixin, Zeng Dongling, Wang Shucheng Feb 2019

Numerical Analysis Of Temperature Field Of Underwater Dredging Artificial Frozen Plate, Wu Yuwei, Hu Jun, Wang Zhixin, Zeng Dongling, Wang Shucheng

Coal Geology & Exploration

In order to understand the development of the temperature field of artificial freeze dredging plates and the process of the formation of frozen curtains, the finite element analysis was used to perform numerical analysis using the single factor analysis method for research of the frozen process in different circumstances of geometric size of plate and physical environment of the soil under water. The results show that the correlation between the different geometric dimensions of the frozen plate and the dredging depth is weak, and the geometric dimension of the frozen plate can only change the area of dredging; for the …

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Method For Determination Of Measurent Time Of Resistivity Logging In Artificial Well Liquid, Wang Haijun, Ma Liang Feb 2019

Method For Determination Of Measurent Time Of Resistivity Logging In Artificial Well Liquid, Wang Haijun, Ma Liang

Coal Geology & Exploration

In order to solve the problem of determining the most critical parameter of the logging time of artificial well fluid resistivity logging, and get rid of the method that depends on the construction experience for a long time, guide logging technicians to obtain reliable logging curves, from the factors influencing the measurement time, the mass conservation law was used to build the calculation model for the best measurement time of logging, the computational formula for the best measurement time was derived, which was verified through in-site contrast experiment of boreholes. The results show that the computational formula set up by …

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Properties Of Mud Cake Associated With Silica Shale Powder Intrusion Into Drilling Fluid, Mo Dingqiang, Sun Pinghe, Zhao Binkui, Wang Jingyuan, Zhang Shaohe, Cao Han Feb 2019

Properties Of Mud Cake Associated With Silica Shale Powder Intrusion Into Drilling Fluid, Mo Dingqiang, Sun Pinghe, Zhao Binkui, Wang Jingyuan, Zhang Shaohe, Cao Han

Coal Geology & Exploration

Drilling fluid is very important for maintaining the stability of the hole wall in shale drilling. The mud cake formed by the fluid loss also plays a decisive role in protecting the reservoir. In order to study the influence of shale rock powder intrusion into low-solid-phase drilling fluids on the basic properties of mud cakes, the paper selects the siliceous shale powders in northwestern Hunan as the research object, and designs orthogonal experiments. In addition, the test results are analyzed using variance and range, which show that the content of rock powder is the main factor affecting the thickness of …

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Genome-Wide Association Studies For Yield-Related Traits In Soft Red Winter Wheat Grown In Virginia, Brian P. Ward, Gina Brown-Guedira, Frederic L. Kolb, David A. Van Sanford, Priyanka Tyagi, Clay H. Sneller, Carl A. Griffey Feb 2019

Genome-Wide Association Studies For Yield-Related Traits In Soft Red Winter Wheat Grown In Virginia, Brian P. Ward, Gina Brown-Guedira, Frederic L. Kolb, David A. Van Sanford, Priyanka Tyagi, Clay H. Sneller, Carl A. Griffey

Plant and Soil Sciences Faculty Publications

Grain yield is a trait of paramount importance in the breeding of all cereals. In wheat (Triticum aestivum L.), yield has steadily increased since the Green Revolution, though the current rate of increase is not forecasted to keep pace with demand due to growing world population and increasing affluence. While several genome-wide association studies (GWAS) on yield and related component traits have been performed in wheat, the previous lack of a reference genome has made comparisons between studies difficult. In this study, a GWAS for yield and yield-related traits was carried out on a population of 322 soft red …

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Soil Macroinvertebrate Presence Alters Microbial Community Composition And Activity In The Rhizosphere, Natalie Bray, Jenny Kao-Kniffin, Serita D. Frey, Timothy Fahey, Kyle Wickings Feb 2019

Soil Macroinvertebrate Presence Alters Microbial Community Composition And Activity In The Rhizosphere, Natalie Bray, Jenny Kao-Kniffin, Serita D. Frey, Timothy Fahey, Kyle Wickings

Faculty Publications

Soil Macroinvertebrate Presence Alters Microbial Community Composition and Activity in the Rhizosphere

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The Influence Of Fetch On The Holocene Thermal Structure Of Hidden Lake, Glacier National Park, Jeffery R. Stone, Jasmine E. Saros, Trisha L. Spanbauer Feb 2019

The Influence Of Fetch On The Holocene Thermal Structure Of Hidden Lake, Glacier National Park, Jeffery R. Stone, Jasmine E. Saros, Trisha L. Spanbauer

Department of Earth and Atmospheric Sciences: Faculty Publications

We use three-dimensional modeling of the basin of Hidden Lake, Montana, to assess the influence of effective fetch on diatom-inferred changes in mixing depths throughout the Holocene. The basin of Hidden Lake is characterized by a complex morphometry; for example, three-dimensional modeling of the lake basin indicates that a decrease in lake level of 2 m would result in complete isolation of the deepest part of the lake basin from the rest of the lake. Our model suggests that small changes in the lake surface elevation at Hidden Lake would produce threshold-like responses in effective fetch, which in turn would …

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Survey And Adjourn, Kentucky Alfalfa And Stored Forages Conference Feb 2019

Survey And Adjourn, Kentucky Alfalfa And Stored Forages Conference

Kentucky Alfalfa and Stored Forage Conference

No abstract provided.

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How Good Is Our Kentucky Haylage? A Summary Of 2017-18 Farm Results, Jimmy C. Henning, Jeff Lehmkuhler, Levi Berg, April Wilhoit, Corinne Belton, Tommy R. Yankey Feb 2019

How Good Is Our Kentucky Haylage? A Summary Of 2017-18 Farm Results, Jimmy C. Henning, Jeff Lehmkuhler, Levi Berg, April Wilhoit, Corinne Belton, Tommy R. Yankey

Kentucky Alfalfa and Stored Forage Conference

The ability to harvest moist forage as hay gives Kentucky producers many advantages, including timely harvest, higher forage quality, and less weathering loss over hay systems. The baleage system allows producers to utilize commonly available forage equipment (mowers, rakes, balers) rather than requiring choppers and silo structures or bags. Making high quality baleage requires timely access to bale wrappers.

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Forward Of Kentucky Alfalfa And Stored Forages Conference [2019], Rehanon Pampell, S. Ray Smith Feb 2019

Forward Of Kentucky Alfalfa And Stored Forages Conference [2019], Rehanon Pampell, S. Ray Smith

Kentucky Alfalfa and Stored Forage Conference

No abstract provided.

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Solute Fluxes Through Restored Prairie And Intensively Managed Critical Zones In Nebraska And Iowa, Ashlee L. Dere, Andrew W. Miller, Amy M. Hemje, Sara K. Parcher, Courtney A. Capalli, E. Arthur Bettis Iii Feb 2019

Solute Fluxes Through Restored Prairie And Intensively Managed Critical Zones In Nebraska And Iowa, Ashlee L. Dere, Andrew W. Miller, Amy M. Hemje, Sara K. Parcher, Courtney A. Capalli, E. Arthur Bettis Iii

Geography and Geology Faculty Publications

Agricultural activities in the Midwestern United States have potentially altered geochemical fluxes within the critical zone (CZ) compared to native prairie systems that previously dominated the region. To quantify the impact of agricultural land use on soil and stream solute behavior, we are studying two watersheds in the region: Glacier Creek Preserve (GCP) in eastern Nebraska and the Intensively Managed Landscapes Critical Zone Observatory (IML-CZO) in eastern Iowa. Both watersheds were initially under agricultural land use for over 100 years, but part of each watershed was restored to prairie 20 – 50 years ago. Soils at both sites formed in …

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Newgeochemical Evidence For The Origin Of North America's Largest Dune Field, The Nebraska Sand Hills, Central Great Plains, Usa, Daniel R. Muhs, James R. Budahn Feb 2019

Newgeochemical Evidence For The Origin Of North America's Largest Dune Field, The Nebraska Sand Hills, Central Great Plains, Usa, Daniel R. Muhs, James R. Budahn

United States Geological Survey: Staff Publications

The Nebraska SandHills region is the largest dune field inNorthAmerica and has diverse aeolian landforms. It has been active during both the late Pleistocene and late Holocene. Despite decades of study, the source of sediment for this large sand sea is still controversial. Here we report new trace element compositions of aeolian sand that are compared to four hypothesized sediment sources, Tertiary rocks of the Arikaree Group and Ogallala Group, unconsolidated sands of Pliocene age, and Platte River systemsands. All four potential sources have amineralogy that is similar to the Nebraska Sand Hills. K/Rb, K/Ba, Sc-Th-La, Eu/Eu*, LaN/YbN, As/Sb, and …

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Testing Pyroxenite Versus Peridotite Sources For Marine Basalts Using U-Series Isotopes, Lynne J. Elkins, Bernard Bourdon, Sarah Lambart Feb 2019

Testing Pyroxenite Versus Peridotite Sources For Marine Basalts Using U-Series Isotopes, Lynne J. Elkins, Bernard Bourdon, Sarah Lambart

Department of Earth and Atmospheric Sciences: Faculty Publications

Geochemically enriched signatures in global oceanic basalts have long indicated a heterogeneous mantle source, but the role of lithologic heterogeneity in producing mantle partial melts, particularly fertile pyroxenite rocks, remains unclear. Uranium-series disequilibria in basalts are particularly sensitive to the increased garnet mode and melting rates of pyroxenite rocks, making the system a useful indicator of mantle lithologic heterogeneity in the melt region for oceanic basalts. Here we summarize evidence for the presence and importance of pyroxenite rocks in the upper mantle and their role in melt generation of mid-ocean ridge basalts and ocean island basalts, with a synthesis of …

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