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Articles 10951 - 10980 of 59515

Full-Text Articles in Earth Sciences

Cover Cropping And Organic Amendments To Improve Sandy Soils Under Organic Vegetable Production, Charles Williamson Dec 2022

Cover Cropping And Organic Amendments To Improve Sandy Soils Under Organic Vegetable Production, Charles Williamson

All Theses

Coastal Plain soils in the Southeastern USA are typically sandy with poor soil structure, low soil organic carbon (SOC) content, and meager soil fertility that pose challenges to organic agriculture. Adding organic inputs is a strategy to improve these soils' physical, chemical, and biological characteristics. Here, we aim to investigate the impacts of Cover Cropping (CC) and manure inclusions on sandy soils under organic vegetable production. The experiment design was a randomized complete block with two treatments of manure application (with and without) and four CC treatments of cereal rye (Secale cereale), hairy vetch (Vicia villosa), …

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Us Scientific Leadership Addressing Energy, Ecosystems, Climate, And Sustainable Prosperity: Report In Brief From The Berac Subcommittee On International Benchmarking, Maureen Mccann, Patrick Reed, Ana Alonso, Ludmilla Aristilde, Massie S. Ballon, Crysten Blaby, Allison A. Campbell, Kenneth James Davis, Brian H. Davison, Ben Evans, Robert F. Fischetti, Serita D. Frey, Ann M. Fridlind, Efi Foufoula-Georgiou, Ramon Gonzalez, Michael N. Gooseff, Nathan Hillson, Janet Jansson, Klaus Keller, Markus Kleber, Costas Maranas, Gerald A. Meehl, Himadri Pakrasi, Jennifer Pett-Ridge, Kristala Prather, Johannes Quaas, G. Philip Robertson, Alistair Rogers, Tim Scheibe, Thomas R. Schneider, Gary Stacey, Margaret S. Torn, Kerstin Kleese Van Dam, Detlef Vuuren, John Weyant, Stan Wullschleger, Shaocheng Xie, Seung Yon (Sue) Rhee, Huimin Zhao Dec 2022

Us Scientific Leadership Addressing Energy, Ecosystems, Climate, And Sustainable Prosperity: Report In Brief From The Berac Subcommittee On International Benchmarking, Maureen Mccann, Patrick Reed, Ana Alonso, Ludmilla Aristilde, Massie S. Ballon, Crysten Blaby, Allison A. Campbell, Kenneth James Davis, Brian H. Davison, Ben Evans, Robert F. Fischetti, Serita D. Frey, Ann M. Fridlind, Efi Foufoula-Georgiou, Ramon Gonzalez, Michael N. Gooseff, Nathan Hillson, Janet Jansson, Klaus Keller, Markus Kleber, Costas Maranas, Gerald A. Meehl, Himadri Pakrasi, Jennifer Pett-Ridge, Kristala Prather, Johannes Quaas, G. Philip Robertson, Alistair Rogers, Tim Scheibe, Thomas R. Schneider, Gary Stacey, Margaret S. Torn, Kerstin Kleese Van Dam, Detlef Vuuren, John Weyant, Stan Wullschleger, Shaocheng Xie, Seung Yon (Sue) Rhee, Huimin Zhao

Faculty Publications

This document presents the subcommittee’s overarching and domain-specific findings and recommendations for the next decade, identified by consensus across the full BERAC subcommittee and experts interviewed for this assessment.

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Age And Genesis Of W-Mo-Cu Mineralization, Gold Hill, Utah, Nathan J. Carey Dec 2022

Age And Genesis Of W-Mo-Cu Mineralization, Gold Hill, Utah, Nathan J. Carey

UNLV Theses, Dissertations, Professional Papers, and Capstones

Utah's Gold Hill mining district hosts a Jurassic felsic pluton (~80 km^2) that was emplaced into a Mississippian to Pennsylvanian carbonate-dominated sedimentary sequence and is spatially associated with numerous polymetallic mineral deposits. This study focuses on W-Mo-Cu mineralization at the Lucy L., Doctor, Yellow Hammer, Reaper, and Rustler deposits within the district. The new, detailed petrographic observations, mineral chemistry (on scheelite, molybdenite, chalcopyrite, magnetite, garnet, and pyroxene), and Re-Os molybdenite geochronological data presented here allows for the determination of key mineral associations and paragenesis, the characterization of deposit types and their evolution, and the constraining of the relative and absolute …

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Hydrogeologic Heterogeneity Identification: Using Inverse Modeling Of Synthetic Borehole Temperatures To Predict Groundwater Flux, Kevin Heintz Dec 2022

Hydrogeologic Heterogeneity Identification: Using Inverse Modeling Of Synthetic Borehole Temperatures To Predict Groundwater Flux, Kevin Heintz

UNLV Theses, Dissertations, Professional Papers, and Capstones

Heat has been effectively used as a groundwater tracer for decades, and high-resolution temperature data can better identify and quantify discrete flow zones. Refinements to the numerical modeling of advective heat transfer in borehole temperature sensing deployments can improve understanding of dynamic hydrogeologic systems. In my thesis, I develop a novel two-dimensional coupled radial groundwater flow and heat transfer numerical model that considers intra-borehole vertical flow. To test the performance of this model, I used finite element analysis to generate synthetic data sets consisting of prescribed variable flow fields and resulting borehole temperatures. I input synthetic temperatures into the two-dimensional …

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Calcite Spherulite Formations And Their Controls In Halophilic Bacterial Cultures, Zakaria Jibrin Dec 2022

Calcite Spherulite Formations And Their Controls In Halophilic Bacterial Cultures, Zakaria Jibrin

UNLV Theses, Dissertations, Professional Papers, and Capstones

This study arose from an accidental discovery of calcite spherulites forming on colonies of various halophilic bacteria grown on solid Luria-Bertani medium made containing water from a brine pool in Death Valley, their natural habitat. Further studies with a large spherulite forming bacteria, Pseudoalteromonas haloplanktis, showed that calcite precipitation conditions were the consequence of bacteria using amino acids as a source of carbon and energy, a metabolism that produces NH3 and CO2 waste products. NH3 raises the pH of the medium, turning CO2 into CO32-. Calcium in the natural brine combines with CO32-. The resulting spherulitic calcite precipitation is nano-acicular …

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Along Strike Tectonic Evolution Of The Neogene Bermejo Foreland Basin And Eastern Precordillera Thrust Front, Argentina (30-32ºs), Zoey Catherine Plonka Dec 2022

Along Strike Tectonic Evolution Of The Neogene Bermejo Foreland Basin And Eastern Precordillera Thrust Front, Argentina (30-32ºs), Zoey Catherine Plonka

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Bermejo retroarc foreland basin system formed in flexural response to Miocene crustal thickening in the Andean orogenic system, specifically, the eastward propagation of the Precordillera fold-thrust belt and the basement-involved uplift of the Sierras Pampeanas. Previous work in the area has mainly focused on the mechanisms and expression of flat slab subduction and the structural geometry of the basement-involved Sierras Pampeanas and east-vergent Precordillera fold-thrust belt at depth. Much of this work has furthered the understanding of Bermejo basin evolution north of 31ºS, however debate still exists whether the N-S trending Bermejo basin evolved synchronously or asynchronously through time. …

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Mesozoic Sevier Thrusts Overprinted By Miocene-Quaternary Left-Lateral Deformation: Structures And Tectonism Of The Kane Springs Wash Region, Nevada, Andrew Reid Dec 2022

Mesozoic Sevier Thrusts Overprinted By Miocene-Quaternary Left-Lateral Deformation: Structures And Tectonism Of The Kane Springs Wash Region, Nevada, Andrew Reid

UNLV Theses, Dissertations, Professional Papers, and Capstones

Recognizing how rifts develop through space and time is vital to enrich our understanding of continental breakup. Rifts are commonly segmented by transfer or accommodations zones that form as the rift develops due to differences in the onset, direction, magnitude, or rates of extension on either side of the transfer or accommodation zone. The Basin and Range province is a wide rift where Cenozoic extension overprints and exposes earlier Mesozoic Sevier fold-thrust belt shortening structures. This exposure allows Sevier thrust correlations between individual mountain ranges and use of these shortening structures to study rift segmentation by strike-slip transfer faults. The …

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Tonga Volcanic Eruption And Tsunami, January 2022: Globally The Most Significant Opportunity To Observe An Explosive And Tsunamigenic Submarine Eruption Since Ad 1883 Krakatau, James P. Terry, James Goff, Nigel Winspear, Vena Pearl Bongolan, Scott Fisher Dec 2022

Tonga Volcanic Eruption And Tsunami, January 2022: Globally The Most Significant Opportunity To Observe An Explosive And Tsunamigenic Submarine Eruption Since Ad 1883 Krakatau, James P. Terry, James Goff, Nigel Winspear, Vena Pearl Bongolan, Scott Fisher

All Works

January 2022 witnessed the violent eruption of Hunga Tonga–Hunga Haʻapai submarine volcano in the South Pacific. With a volcanic explosivity index possibly equivalent to VEI 5, this represents the largest seaborne eruption for nearly one and a half centuries since Indonesia’s cataclysmic explosion of Krakatau in AD 1883. The Tongan eruption remarkably produced ocean-wide tsunamis, never documented before in the Pacific instrumental record. Volcanically generated tsunamis have been referred to as a ‘blind spot’ in our understanding of tsunami hazards, particularly in the Pacific Ocean. This event therefore presents a unique opportunity for investigating the multiple processes contributing to volcanic …

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Nitrogen Use Efficiency Of Pretassel Nitrogen Applications In Corn, Robyn Brittlee Mulloy Dec 2022

Nitrogen Use Efficiency Of Pretassel Nitrogen Applications In Corn, Robyn Brittlee Mulloy

Graduate Theses and Dissertations

Corn (Zea mays L.) production continues to be a critical component of row-crop production systems within Arkansas and is seeing a resurgence in recent years. Nitrogen (N) is critical for corn growth and is often one of the single largest input costs associated with corn production. Research objectives for this study were to determine the nitrogen use efficiency (NUE) of late season N applications as influenced by sidedress N rate and timing of pretassel application and to quantify the nutrient uptake and partitioning in modern era corn hybrids within a furrow-irrigated production system. Research was conducted at the Milo J. …

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Nitrogen Management In Rice Under Suboptimal Soil Conditions, Payton Suzanne Rhea Dec 2022

Nitrogen Management In Rice Under Suboptimal Soil Conditions, Payton Suzanne Rhea

Graduate Theses and Dissertations

In Mid-South rice (Oryza sativa, L.) production, nitrogen (N) fertilizer management for pureline varieties is most often recommended as a single preflood (SPF) or two-way split (2WS) application in a direct-seeded, delayed-flood system. Most of the N fertilizer is typically applied at the four- to six-leaf stage onto dry soil, and the second application, if necessary, into the floodwater during early reproductive growth stages (referred to as midseason). Environmental factors frequently prohibit growers from applying early N fertilizer under optimal dry soil conditions. A study was conducted to determine the best N fertilization management practices to utilize in rice when …

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Orbital Mapping Of Seasonal And Yearly Changes In Co2 And Water Ice On The Southern Polar Cap Of Mars, Victoria Michell Ann Karnes Dec 2022

Orbital Mapping Of Seasonal And Yearly Changes In Co2 And Water Ice On The Southern Polar Cap Of Mars, Victoria Michell Ann Karnes

Graduate Theses and Dissertations

This research exhibits a new foundation for the rates of change in CO2 and water ice on the southern polar cap of Mars, where the annual precipitation cycles are known to fluctuate seasonally between the north and south pole, based on observations from the Compact Reconnaissance Imaging Spectrometer (CRISM). The conventional belief is that both CO2 ice and water ice on the southern polar cap condenses and evaporates over the course of a Martian year (MY), condensing during the Martian spring and summer and evaporating during the Martian fall and winter. With this theory in mind, CO2 and water ice …

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The Binding Of The Micronutrient Transition Metals To The Alkylation Products Of Chemical Warfare Agent, Sulfur Mustard, And Thiols, Potentially Giving New Understanding To Physiological Effects Of Exposure And Increased Toxicity, Colin O'Donnell Dec 2022

The Binding Of The Micronutrient Transition Metals To The Alkylation Products Of Chemical Warfare Agent, Sulfur Mustard, And Thiols, Potentially Giving New Understanding To Physiological Effects Of Exposure And Increased Toxicity, Colin O'Donnell

Graduate Theses and Dissertations

Model compounds, 3,6,9-trithaiundecane-1,11-dicarboxylic acid (TTDPA), 2,5,8-trithianonane-1,9-dicarboxylic acid (TTDAA), and 1,11-diamide-3,6,9-trithiaundecane (TTDAce), closely related to the adducts formed by cysteine alkylation of the chemical weapon, sulfur mustard, were synthesized. It is shown that TTDPA forms complexes with key metal micronutrients: copper, nickel, cobalt, manganese, and zinc. Though the strength of binding to TTDPA varies, the complexes in many cases precipitate from solution. All metals produced a visible precipitate upon interaction with TTDPA under the conditions tested, however only Cu2+, Mn2+, and Zn2+ produced enough to be measured. The mass of formed precipitate seemed to peak at an equimolar ratio of TTDPA …

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Diagnosing Excess Nitrogen In Rice Using Post-Season Tissue Samples, Kyle Hoegenauer Dec 2022

Diagnosing Excess Nitrogen In Rice Using Post-Season Tissue Samples, Kyle Hoegenauer

Graduate Theses and Dissertations

Proper nitrogen (N) management in rice production can be difficult to achieve without the aid of tools such as soil and tissue tests. There are no tests currently available to rice producers that determine whether N has been managed properly throughout the season or that detect instances of over fertilization. Rice stalk samples were collected from N response trials within 3 days of harvest from the primary Arkansas rice growing region in 2016-2018. Stalk samples were analyzed for N concentration through a KCl extraction and spectrofluorometric quantification. Samples analyzed with leaf material intact contained statistically different N concentrations than samples …

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Delineating Field Variation Using Apparent Electrical Conductivity In An Ozark Highlands Agroforestry System, Shane Reid Ylagan Dec 2022

Delineating Field Variation Using Apparent Electrical Conductivity In An Ozark Highlands Agroforestry System, Shane Reid Ylagan

Graduate Theses and Dissertations

Little to no work has been conducted assessing field variability using repeated electromagnetic induction (EMI) apparent electrical conductivity (ECa) surveys in agroforestry (AF) systems within regions similar to the Ozark Highlands. The objectives of this thesis were to identify i) spatiotemporal ECa variability; ii) ECa-derived soil management zones (SMZs); iii) correlations among EMI-ECa and in-situ, sentential-site soil properties; iv) whether fewer, EMI-ECa surveys could be conducted to capture similar ECa variance as mid-monthly EMI-ECa surveys; v) correlations between ECa and forage yield, tree growth, and terrain attributes based on plant (forage and tree) species, and fertility treatments, and ECa-derived SMZs, …

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Physical Controls On The Hydrology Of Perennially Ice-Covered Lakes, Taylor Valley, Antarctica (1996-2013), J. M. Cross, Andrew G. Fountain, M. J. Hoffman, M. K. Obryk Dec 2022

Physical Controls On The Hydrology Of Perennially Ice-Covered Lakes, Taylor Valley, Antarctica (1996-2013), J. M. Cross, Andrew G. Fountain, M. J. Hoffman, M. K. Obryk

Geology Faculty Publications and Presentations

The McMurdo Dry Valleys, Antarctica, are a polar desert populated with numerous closed-watershed, perennially ice-covered lakes primarily fed by glacial melt. Lake levels have varied by as much as 8 m since 1972 and are currently rising after a decade of decreasing. Precipitation falls as snow, so lake hydrology is dominated by energy available to melt glacier ice and to sublimate lake ice. To understand the energy and hydrologic controls on lake level changes and to explain the variability between neighboring lakes, only a few kilometers apart, we model the hydrology for the three largest lakes in Taylor Valley. We …

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Substrate Availability And Not Thermal Acclimation Controls Microbial Temperature Sensitivity Response To Long-Term Warming, Luiz A. Domeignoz-Horta, Grace Pold, Hailey Erb, David Sebag, Eric Verrecchia, Trent Northen, Katherine Louie, Emiley Eloe-Fadrosh, Christa Pennacchio, Melissa A. Knorr, Serita D. Frey, Jerry M. Melillo, Kristen M. Deangelis Nov 2022

Substrate Availability And Not Thermal Acclimation Controls Microbial Temperature Sensitivity Response To Long-Term Warming, Luiz A. Domeignoz-Horta, Grace Pold, Hailey Erb, David Sebag, Eric Verrecchia, Trent Northen, Katherine Louie, Emiley Eloe-Fadrosh, Christa Pennacchio, Melissa A. Knorr, Serita D. Frey, Jerry M. Melillo, Kristen M. Deangelis

Faculty Publications

Microbes are responsible for cycling carbon (C) through soils, and predicted changes in soil C stocks under climate change are highly sensitive to shifts in the mechanisms assumed to control the microbial physiological response to warming. Two mechanisms have been suggested to explain the long-term warming impact on microbial physiology: microbial thermal acclimation and changes in the quantity and quality of substrates available for microbial metabolism. Yet studies disentangling these two mechanisms are lacking. To resolve the drivers of changes in microbial physiology in response to long-term warming, we sampled soils from 13- and 28-year-old soil warming experiments in different …

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Spinosaurus Is Not An Aquatic Dinosaur, Paul C. Sereno, Nathan Myhrvold, Donald M. Henderson, Frank E. Fish, Stephanie L. Baumgart, Tyler M. Keillor, Kiersten K. Formoso, Lauren L. Conroy Nov 2022

Spinosaurus Is Not An Aquatic Dinosaur, Paul C. Sereno, Nathan Myhrvold, Donald M. Henderson, Frank E. Fish, Stephanie L. Baumgart, Tyler M. Keillor, Kiersten K. Formoso, Lauren L. Conroy

Biology Faculty Publications

A predominantly fish-eating diet was envisioned for the sail-backed theropod dinosaur Spinosaurus aegyptiacus when its elongate jaws with subconical teeth were unearthed a century ago in Egypt. Recent discovery of the high-spined tail of that skeleton, however, led to a bolder conjecture that S. aegyptiacus was the first fully aquatic dinosaur. The "aquatic hypothesis' posits that S. aegyptiacus was a slow quadruped on land but a capable pursuit predator in coastal waters, powered by an expanded tail. We test these functional claims with skeletal and flesh models of S. aegyptiacus. We assembled a CT- based skeletal reconstruction based on the …

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Increased Aerosols Can Reverse Twomey Effect In Water Clouds Through Radiative Pathway, Pradeep Khatri, Tadahiro Hayasaka, Brent N. Holben, Ramesh P. Singh, Husi Letu, Sachchida N. Tripathi Nov 2022

Increased Aerosols Can Reverse Twomey Effect In Water Clouds Through Radiative Pathway, Pradeep Khatri, Tadahiro Hayasaka, Brent N. Holben, Ramesh P. Singh, Husi Letu, Sachchida N. Tripathi

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Aerosols play important roles in modulations of cloud properties and hydrological cycle by decreasing the size of cloud droplets with the increase of aerosols under the condition of fixed liquid water path, which is known as the first aerosol indirect effect or Twomey-effect or microphysical effect. Using high-quality aerosol data from surface observations and statistically decoupling the influence of meteorological factors, we show that highly loaded aerosols can counter this microphysical effect through the radiative effect to result both the decrease and increase of cloud droplet size depending on liquid water path in water clouds. The radiative effect due to …

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Comparing Past And Future Drought And Surplus Periods In The Colorado River Basin, Rama Bedri Nov 2022

Comparing Past And Future Drought And Surplus Periods In The Colorado River Basin, Rama Bedri

Student Scholar Symposium Abstracts and Posters

The Colorado River Basin is crucial to the Western United States, providing water for seven states and Mexico. Historical and future periods of drought and surplus are analyzed in 17 Colorado River stations. Unimpaired streamflow data are evaluated from the U.S. Geological Survey, Bureau of Reclamation, and Coupled Modeled Intercomparison Projection 5 from 1950-2099. Future projections are based on eight climate scenarios. Four climate models (HadGEM2-ES, CNRM-CM5, CanESM2, MI-ROC5) are observed at Representative Concentration Pathways (RCP) 4.5 and 8.5 emission scenarios. Furthermore, the ensemble water year means of the four models are analyzed. The durations of drought or surplus, magnitudes, …

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Key Technologies And Equipment Of Quickly And Safely Building Life Support And Rescue Channel In Mine Disaster, Tian Hongliang, Zou Zujie, Hao Shijun, Cao Ming, Zhou Guanghua, Huang Yong, Gu Hairong, Wang Lei Nov 2022

Key Technologies And Equipment Of Quickly And Safely Building Life Support And Rescue Channel In Mine Disaster, Tian Hongliang, Zou Zujie, Hao Shijun, Cao Ming, Zhou Guanghua, Huang Yong, Gu Hairong, Wang Lei

Coal Geology & Exploration

In case that persons are trapped underground as a result of shaft and roadway damage due to a major disaster accident in a mine, the most effective way of rescue is to construct the rescue channel in a safely and efficient manner. The rescue channel is divided into the underground and ground types. Building a large diameter rescue channel through the collapsed section is the most direct way if underground construction conditions are available. However, if no underground construction conditions are available or it is prone to secondary disasters, it is necessary to drill small diameter rescue holes on the …

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Key Technologies Of Surface Efficient Life Support Hole Forming For Mine Rescue, Zhang Biao, Kang Yuguo, Huang Yong, Zhang Ming, Zhou Guang, Ren Yingju, Liu Jianlin, Gao Ke, Zhao Yan Nov 2022

Key Technologies Of Surface Efficient Life Support Hole Forming For Mine Rescue, Zhang Biao, Kang Yuguo, Huang Yong, Zhang Ming, Zhou Guang, Ren Yingju, Liu Jianlin, Gao Ke, Zhao Yan

Coal Geology & Exploration

The surface life support hole, as the support channel for the trapped people underground, is one of the important ground emergency rescue schemes for the situation with some people trapped underground due to mine accidents. Under the complex conditions of the rescue area, including easy collapse, easy leakage, large water inflow and inclined formation, the single hole forming process has the problems such as poor ground adaptability matching, low comprehensive drilling efficiency and difficult roadway penetration, which cannot meet the requirements of rescue. In order to form an efficient drilling technology system for life support holes and improve the response …

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Research Progress Of Lifting Equipment For Large-Diameter Borehole Rescue, Gu Hairong, Shan Zenghai, Wang Longpeng, Shao Tao, Zou Zujie, Gao Ziyu Nov 2022

Research Progress Of Lifting Equipment For Large-Diameter Borehole Rescue, Gu Hairong, Shan Zenghai, Wang Longpeng, Shao Tao, Zou Zujie, Gao Ziyu

Coal Geology & Exploration

Rescue through large-diameter relief well is an efficient method of mine emergency rescue. The lifting equipment of large-diameter relief well is used to lift the trapped personnel safely and reliably to the surface through the large-diameter relief well. It is the key equipment in the rescue system of large-diameter relief well. With the rescue technology of large-diameter relief well gradually recognized in the industry, the lifting equipment of large-diameter relief well has developed considerably, forming the fixed and mobile types of lifting equipment and multiple technical routes. Besides, important progress has been made in the research on the lifting equipment …

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Research And Application Of Synchronous Self-Balancing Feed System For Rescue Truck-Mounted Drilling Rig, Zou Zujie, Tian Hongliang, Liu Qingxiu, Chang Jianghua, Liu Qi, Zhu Guodong Nov 2022

Research And Application Of Synchronous Self-Balancing Feed System For Rescue Truck-Mounted Drilling Rig, Zou Zujie, Tian Hongliang, Liu Qingxiu, Chang Jianghua, Liu Qi, Zhu Guodong

Coal Geology & Exploration

Truck-mounted drilling rig is the core equipment of ground drilling rescue in mine accidents, and it has played an important role in all the successful rescues at home and abroad. However, the feed system, as the main actuator of the truck-mounted drilling rig, exposes the problems of restricted passability of the whole machine due to the long working stroke, difficult maintenance of the positioning wheel train, poor movement synchronization of the double cylinder, guide rail wearing caused by the partial load of power head, and the delay of pulling force displayed by the hydraulic gauge during its service. ZMK5550TZJF50/120 rescue …

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Main Influencing Factors For Regional Pre-Grouting Technology Of Water Hazard Treatment In Coal Seam Floor And Efficient Hole Arrangement, Hu Weiyue, Zhao Chunhu, Lyu Hanjiang Nov 2022

Main Influencing Factors For Regional Pre-Grouting Technology Of Water Hazard Treatment In Coal Seam Floor And Efficient Hole Arrangement, Hu Weiyue, Zhao Chunhu, Lyu Hanjiang

Coal Geology & Exploration

Regional advance grouting transformation and reinforcement of water conducting formation and aquifer is the main technical means to prevent and control the karst water hazards in the coal seam floor of North China type coalfields. Herein, analysis was conducted for the general application mode of the regional advance grouting transformation and reinforcement for water hazard treatment in the thin and thick limestone layers in the coal seam floor based on the basic mine hydrogeological principle of the application of regional advance grouting transformation technology. In the analysis, consideration was given to the hydrogeological structure of the coal seam floor, the …

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Key Pretreatment Technologies For Coalbed Gas Bioengineering And Review On Their Mechanism Of Action, Bao Yuan, Chang Jianing, Liu Xiangrong, Xia Daping, Wang Yaya Nov 2022

Key Pretreatment Technologies For Coalbed Gas Bioengineering And Review On Their Mechanism Of Action, Bao Yuan, Chang Jianing, Liu Xiangrong, Xia Daping, Wang Yaya

Coal Geology & Exploration

Coalbed gas bioengineering (CGB) is a new technology for the purpose of realizing the clean utilization of coal resources and the enhanced recovery of coalbed gas. To explore the key characteristics of the pretreatment technologies of CGB, hydrocarbon generation potential and its mechanism of action, conclusion and summary was made for various pretreatment technologies herein. Meanwhile, the pretreatment technologies were divided into three types according to the action mode of coal (organic matter) and bacteria (microorganism): microflora optimization and improvement, coal dissolution and oxidation, and biological stimulation and synergy. By comparing the capability of coal to generate methane through microbial …

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Occurrence Characteristics And Ecological Risk Assessment Of Heavy Metals In Fly Ash Of Ningdong Energy Chemical Industry Base, Zhang Zhiguo, Tan Yuning, Hu Youbiao, Zheng Yonghong, Chen Denghong, Cai Weiqing, Li Yating, Lu Jiangwei Nov 2022

Occurrence Characteristics And Ecological Risk Assessment Of Heavy Metals In Fly Ash Of Ningdong Energy Chemical Industry Base, Zhang Zhiguo, Tan Yuning, Hu Youbiao, Zheng Yonghong, Chen Denghong, Cai Weiqing, Li Yating, Lu Jiangwei

Coal Geology & Exploration

In order to expand the resource utilization of fly ash, research was conducted based on the fly ash of Yuanyang Lake Power Plant in the Ningdong Energy Chemical Industry Base. Specifically, the physical and chemical properties of fly ash were characterized and analyzed by means of scanning electron microscope, energy spectrum analysis and X-ray diffraction. Besides, the total amount, effective state and content in different forms of Pb, Cr, Ni, Cu, Cd and As in fly ash were determined through acid digestion, DTPA extraction and 5-step Tessier sequential extraction. In addition, the ecological risk of heavy metals in fly ash …

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Heat Conduction Performance And Transfer Mechanism Of Sand-Barite Powder Backfill Materials, Jia Hailiang, Zhu Zixian, Zhou Yang, Sun Qiang Nov 2022

Heat Conduction Performance And Transfer Mechanism Of Sand-Barite Powder Backfill Materials, Jia Hailiang, Zhu Zixian, Zhou Yang, Sun Qiang

Coal Geology & Exploration

The ground source heat pump of buried pipeline is a major form of shallow thermal energy utilization, and the thermophysical properties of backfill materials, especially the thermal conductivity, are the key factors affecting the heat transfer efficiency of the heat pump system. In this paper, the variation law of thermal conductivity of the sand-barite powder samples at different barite powder mixing ratio (volume fraction) and saturation was studied. The mechanism of improving the thermal conductivity of backfill materials with barite powder was revealed based on the macroscopic and microscopic experiments such as stereoscope and nuclear magnetic resonance analysis. In addition, …

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Tomography Method For Adjacent Channel Frequency Shift Of Transmitted In-Seam Waves, Tian Han, Wu Rongxin, Hu Ze’An, Yang Qiaonan Nov 2022

Tomography Method For Adjacent Channel Frequency Shift Of Transmitted In-Seam Waves, Tian Han, Wu Rongxin, Hu Ze’An, Yang Qiaonan

Coal Geology & Exploration

In-Seam Seismic is one of the main detection methods for small geological structures in the coal mining working face. In this method, the energy attenuation feature of in-seam waves is mainly utilized. In case of any significant geological anomaly or receivers coupling difference in coal working face, the energy distribution of the in-seam wave at different frequency bands will be significantly affected, and the stability and accuracy of in-seam wave detection results will be decreased. Using the centroid frequency change features of the in-seam wave signals for inversion imaging is an innovative, effective method. However, for this method, there are …

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Development Of Rescue Truck-Mounted Drilling Rig In Ground Emergency, Fan Dong, Zou Zujie, Wang Ruize, Lu Feifei, Liu Qi, Wang Hejian Nov 2022

Development Of Rescue Truck-Mounted Drilling Rig In Ground Emergency, Fan Dong, Zou Zujie, Wang Ruize, Lu Feifei, Liu Qi, Wang Hejian

Coal Geology & Exploration

Ground drilling is an effective means to rescue the person trapped underground in case of accident in a mine. The rescue truck-mounted drilling rig is an ideal model for mine accident rescue due to its adaptability to a variety of drilling technologies and the advantages of wide formation adaptability, high mobility and strong accident handling capacity. In view of the shortcomings of domestic truck-mounted drilling rig in the construction of life support hole and large-diameter relief well, ZMK5550TZJF50/120 truck-mounted drilling rig was developed. Specifically, the large capacity power head adaptable to various technologies was developed, adopting the design of installation …

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Adaptive Electro-Hydraulic System Of Zmk5550tzjf50/120 Truck-Mounted Drilling Rig With Wob Adaptive Control Function, Chang Jianghua, Zhao Liang, Lu Feifei, Wang Longpeng, Yang Jiangbo Nov 2022

Adaptive Electro-Hydraulic System Of Zmk5550tzjf50/120 Truck-Mounted Drilling Rig With Wob Adaptive Control Function, Chang Jianghua, Zhao Liang, Lu Feifei, Wang Longpeng, Yang Jiangbo

Coal Geology & Exploration

The truck-mounted drilling rig is an ideal model for rescue drilling construction due to its strong mobility and wide process adaptability. The traditional truck-mounted drilling rig adopting the mode of hydraulic control and hydraulic drive has the problems of non-intuitive displaying of control parameters and many pipelines, which is hard to achieve the closed-loop control. In case of drilling into the complex formations, the response speed of the driller is often difficult to adapt to changes in working conditions, which is not conducive to the drilling safety. In order to meet the requirements of safety and high automation of rescue …

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