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Articles 69931 - 69960 of 294604

Full-Text Articles in Physical Sciences and Mathematics

A Comparison Of Bayesian Spatial Models For Hiv Mapping In South Africa, Kassahun Abere Ayalew, Samuel Manda, Bo Cai Ph.D. Oct 2021

A Comparison Of Bayesian Spatial Models For Hiv Mapping In South Africa, Kassahun Abere Ayalew, Samuel Manda, Bo Cai Ph.D.

Faculty Publications

Despite making significant progress in tackling its HIV epidemic, South Africa, with 7.7 million people living with HIV, still has the biggest HIV epidemic in the world. The Government, in collaboration with developmental partners and agencies, has been strengthening its responses to the HIV epidemic to better target the delivery of HIV care, treatment strategies and prevention services. Population-based household HIV surveys have, over time, contributed to the country’s efforts in monitoring and understanding the magnitude and heterogeneity of the HIV epidemic. Local-level monitoring of progress made against HIV and AIDS is increasingly needed for decision making. Previous studies have …


Assessing The Vertical Displacement Of The Grand Ethiopian Renaissance Dam During Its Filling Using Dinsar Technology And Its Potential Acute Consequences On The Downstream Countries, Hesham El-Askary, Amr Fawzy, Rejoice Thomas, Wenzhao Li, Nicholas Lahaye, Erik Linstead, Thomas Piechota, Daniele Struppa, Mohamed Abdelaty Sayed Oct 2021

Assessing The Vertical Displacement Of The Grand Ethiopian Renaissance Dam During Its Filling Using Dinsar Technology And Its Potential Acute Consequences On The Downstream Countries, Hesham El-Askary, Amr Fawzy, Rejoice Thomas, Wenzhao Li, Nicholas Lahaye, Erik Linstead, Thomas Piechota, Daniele Struppa, Mohamed Abdelaty Sayed

Mathematics, Physics, and Computer Science Faculty Articles and Research

The Grand Ethiopian Renaissance Dam (GERD), formerly known as the Millennium Dam, is currently under construction and has been filling at a fast rate without sufficient known analysis on possible impacts on the body of the structure. The filling of GERD not only has an impact on the Blue Nile Basin hydrology, water storage and flow but also poses massive risks in case of collapse. Rosaries Dam located in Sudan at only 116 km downstream of GERD, along with the 20 million Sudanese benefiting from that dam, would be seriously threatened in case of the collapse of GERD. In this …


Residential Curbside Recycle Context Analysis, Ntchanang Mpafe Oct 2021

Residential Curbside Recycle Context Analysis, Ntchanang Mpafe

USF Tampa Graduate Theses and Dissertations

Curbside recycling as a preferred mode of residential and municipal sustainability goals seems to have an overwhelming acceptance and adoption in the US. About 69.8 million out of 97.3 million (72%) single-family households in the United States have access to curbside recycling services (State of Curbside Recycling Report, 2020). Collectively, the programs divert about nine million tons of recyclables from landfill disposal each year (Cottom, 2019).

For a design that started in the 1980s in the US, its rapid universal adoption seems to have precluded a concerted effort in examining the coproduced nature (Households: service receptors and Municipalities: service providers) …


Texturing In Bi2Te3 Alloy Thermoelectric Materials: An Applied Physics Investigation, Oluwagbemiga P. Ojo Oct 2021

Texturing In Bi2Te3 Alloy Thermoelectric Materials: An Applied Physics Investigation, Oluwagbemiga P. Ojo

USF Tampa Graduate Theses and Dissertations

Thermoelectric devices provide the means for direct conversion between heat and electricity. The device conversion efficiency, or performance, is directly related to the thermoelectric figure of merit, ZT, of the working materials. Bismuth telluride alloys are the materials currently in use in most thermoelectric devices for near room temperature solid-state refrigeration and power conversion applications. The vast majority of publications in the literature on thermoelectricity report on investigations towards developing new materials with enhanced thermoelectric properties, however Bi2Te3 alloys have been used in thermoelectric devices for decades.

In this thesis, an investigation of crystallographic texturing on large …


Geology & Geography News, Georgia Southern University Oct 2021

Geology & Geography News, Georgia Southern University

Earth, Environment & Sustainability: News & Publications (2013-2021)

  • Homecoming Alumni Breakfast 2021


Check Your Tech - The Ethics Of Gamification In Education, Dympna O'Sullivan, Ioannis Stavrakakis, Damian Gordon, Anna Becevel Oct 2021

Check Your Tech - The Ethics Of Gamification In Education, Dympna O'Sullivan, Ioannis Stavrakakis, Damian Gordon, Anna Becevel

Conference papers

No abstract provided.


Check Your Tech - The Ethics Of Deepfakes In A Political Context, Dympna O'Sullivan, Damian Gordon, Ioannis Stavrakakis, Michael Collins Oct 2021

Check Your Tech - The Ethics Of Deepfakes In A Political Context, Dympna O'Sullivan, Damian Gordon, Ioannis Stavrakakis, Michael Collins

Conference papers

No abstract provided.


Lateral Growth Of Xenon Hydrate Films On Mica, Avinash Kumar Both, Chin Li Cheung Oct 2021

Lateral Growth Of Xenon Hydrate Films On Mica, Avinash Kumar Both, Chin Li Cheung

Department of Chemistry: Faculty Publications

In this paper, we report an in situ optical microscopy study of lateral growth of xenon (Xe) hydrate thin films on mica at sub-zero temperatures. The interactions between a solid surface and water molecules can strongly affect the alignment of water molecules and induce ice-like ordered structures within the water layer at the water-surface interface. Mica was chosen as a model surface to study the surface effect of hydrophilic sheet silicates on the lateral growth of Xe hydrate films. Under the experimental conditions, the lateral growth of Xe hydrate films was measured to be at an average rapid rate of …


Radiocarbon Analyses Quantify Peat Carbon Losses With Increasing Temperature In A Whole Ecosystem Warming Experiment, Rachel M. Wilson, Natalie A. Griffiths, Ate Visser, Karis J. Mcfarlane, Stephen D. Sebestyen, Keith C. Oleheiser, Samantha Bosman, Anya M. Hopple, Malak M. Tfaily, Randall K. Kolka, Paul J. Hanson, Joel E. Kostka, Scott D. Bridgham, Jason K. Keller, Jeffrey P. Chanton Oct 2021

Radiocarbon Analyses Quantify Peat Carbon Losses With Increasing Temperature In A Whole Ecosystem Warming Experiment, Rachel M. Wilson, Natalie A. Griffiths, Ate Visser, Karis J. Mcfarlane, Stephen D. Sebestyen, Keith C. Oleheiser, Samantha Bosman, Anya M. Hopple, Malak M. Tfaily, Randall K. Kolka, Paul J. Hanson, Joel E. Kostka, Scott D. Bridgham, Jason K. Keller, Jeffrey P. Chanton

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Climate warming is expected to accelerate peatland degradation and release rates of carbon dioxide (CO2) and methane (CH4). Spruce and Peatlands Responses Under Changing Environments is an ecosystem-scale climate manipulation experiment, designed to examine peatland ecosystem response to climate forcings. We examined whether heating up to +9 °C to 3 m-deep in a peat bog over a 7-year period led to higher C turnover and CO2 and CH4 emissions, by measuring 14C of solid peat, dissolved organic carbon (DOC), CH4, and dissolved CO2 (DIC). DOC, a major substrate for heterotrophic respiration, increased significantly with warming. There was no 7-year trend …


Method Of Making Temperature-Immune Self-Referencing Fabry–Pérot Cavity Sensors, Hengky Chandrahalim, Jonathan W. Smith Oct 2021

Method Of Making Temperature-Immune Self-Referencing Fabry–Pérot Cavity Sensors, Hengky Chandrahalim, Jonathan W. Smith

AFIT Patents

A method of making passive microscopic Fabry-Pérot Interferometer (FPI) sensor includes forming a three-dimensional microscopic optical structure on a cleaved tip of an optical fiber that reflects a light signal back through the optical fiber. The reflected light is altered by refractive index changes in the three-dimensional structure that is subject to at least one of: (i) thermal radiation; and (ii) volatile organic compounds.


Organic Synthesis, Kevin M. Shea, Libretext Oct 2021

Organic Synthesis, Kevin M. Shea, Libretext

Open Educational Resources: Textbooks

My goal in writing this text is to help advanced undergraduates and beginning graduate students learn key topics in organic chemistry that often don't come up in your Organic I and II classes. So, you can think about this as an Organic III text. My focus is on key reaction types that enable the construction of complex organic molecules: pericyclic reactions, transition metal catalyzed reactions, rearrangements, fragmentations, radical reactions, and carbene reactions. I hope that this text is a resource that helps you understand the mechanisms of these reactions and enables you to use these reactions in your own syntheses. …


A Network Of Transdisciplinary Observation Mechanisms As A Digital Source Of Knowledge On Rangeland, To Communicate And Exchange At Local, Regional And Global Scales, Alessandro Rizzo, El Hassane El Mahdad, Abdelfettah Sifeddine, S. Lucatello, Lhoussaine Bouchaou, Elisabeth Huber-Sannwald Oct 2021

A Network Of Transdisciplinary Observation Mechanisms As A Digital Source Of Knowledge On Rangeland, To Communicate And Exchange At Local, Regional And Global Scales, Alessandro Rizzo, El Hassane El Mahdad, Abdelfettah Sifeddine, S. Lucatello, Lhoussaine Bouchaou, Elisabeth Huber-Sannwald

IGC Proceedings (1977-2023)

For several decades, interventions geared towards the development of drylands have been the catalysts of much change in a rapidly evolving world, and learning how to build sustainable trajectories that take into account both cultural and contextual variations is becoming of increasingly great import. As local problems become intertwined, and given the difficulty of large-scale collective action, understanding these dynamics requires cognizance of all levels of knowledge governance systems and their interactions. So far as rangelands are concerned, the lack of easily accessible documentation encompassing all knowledge to date is a major impediment to their sustainable development. With this in …


Long-Term Socio-Ecological Research In The Biosphere Reserve In Mapimi, Mexico: A Multidimensional Participatory Observatory Of Rangeland/Pastoral Systems, V. M. Reyes Gómez, Elisabeth Huber-Sannwald, N. Martínez Tagüeña, I. Espejel Carvajal, S. Lucatello, M. A. Bowker, C. L. Lauterio Martínez Oct 2021

Long-Term Socio-Ecological Research In The Biosphere Reserve In Mapimi, Mexico: A Multidimensional Participatory Observatory Of Rangeland/Pastoral Systems, V. M. Reyes Gómez, Elisabeth Huber-Sannwald, N. Martínez Tagüeña, I. Espejel Carvajal, S. Lucatello, M. A. Bowker, C. L. Lauterio Martínez

IGC Proceedings (1977-2023)

Since the creation of the UNESCO Biosphere Reserve Mapimi (BRM) in Mexico 45 years ago, pastoralism has undergone a series of transformations. Upon the arrival of the Spaniards, horse breeding flourished until 1900; thereafter extensive cattle production lasted for six decades. Only recently, farmers have adopted alternative management types for organic meat production. National and international efforts to achieve the Sustainable Development Goals (SDGs) require basic, applied, and participatory research efforts. In the socio-ecological pastoral system BRM, first halophytic ecosystems were examined for their ecohydrological role in rangeland productivity. In 1996, a long-term ecological research site was installed to monitor …


Re-Envisioning Global Rangeland Stewardship: An Ecosystem Services Assessment Framework, David D. Briske Oct 2021

Re-Envisioning Global Rangeland Stewardship: An Ecosystem Services Assessment Framework, David D. Briske

IGC Proceedings (1977-2023)

Rangeland stewardship may be enhanced by transforming the global narrative from one of ‘resource scarcity and unpredictability’ to one of ‘global rangeland value’. This may be accomplished by devising a stewardship strategy founded on a more complete accounting of rangeland ecosystem services to inform land use planning and decision making. An ecosystem services framework may provide the necessary feedbacks to identify and assess potential tradeoffs among ecosystem services prior to implementing land use actions and policy. The ultimate goal of this alternative stewardship strategy would be to provide optimal combinations of ecosystem services to meet the needs of global citizens, …


Mongolian Herders’ Evaluation Of Rangeland Ecosystems Services, Values, And Changes Over The Past Decade, T. Ulambayar, B. Yunden, N. Davaasuren, S. Balt, D. Davaajav, B. Zambuu Oct 2021

Mongolian Herders’ Evaluation Of Rangeland Ecosystems Services, Values, And Changes Over The Past Decade, T. Ulambayar, B. Yunden, N. Davaasuren, S. Balt, D. Davaajav, B. Zambuu

IGC Proceedings (1977-2023)

Mongolia's rangeland is one of the largest remaining contiguous ecosystems encompassing 2.6% of the global grasslands, and almost three-fourths of the country's territory provides essential ecosystem services (ESS) for over 3 million Mongolians and 71 million livestock. The well-being of 171,605 pastoral households directly depends on the rangelands receiving provisional services in the forms of nutrition, material use and energy, regulatory services, and cultural services. This study explored herders' perceptions of these ESS, their evaluation for ESS values, and observations of ESS change for the last decade. The study found that Mongolian herders have more benefits from provisional ESS (on …


Conceptualizing Pastoral Development Based On Carbon Sequestration: The Case Of Yabelo District In The Southern Ethiopian Rangelands, D. L. Coppock Oct 2021

Conceptualizing Pastoral Development Based On Carbon Sequestration: The Case Of Yabelo District In The Southern Ethiopian Rangelands, D. L. Coppock

IGC Proceedings (1977-2023)

Major challenges for rangeland stewardship in the developing world include how to mitigate the spread of pastoral poverty and environmental degradation. Arresting such trends requires a scale of investment, policy incentives, and institutional commitments not previously observed in pastoral development. Indeed, such a rangeland revolution requires several global events to set the stage, namely: (1) Creation of markets for diverse ecosystem services; (2) recognition that improved rangeland stewardship is vital to mitigate climate change; and (3) distribution of green climate funds in support of local projects. New approaches for pastoral development projects are also needed. Previous projects have largely focused …


Wildlife Conservation And The Role Of The Indigenous Communities Living Around Conservation Areas, N. Parmisa, K. A. Galvin Oct 2021

Wildlife Conservation And The Role Of The Indigenous Communities Living Around Conservation Areas, N. Parmisa, K. A. Galvin

IGC Proceedings (1977-2023)

The Indigenous Kenyan Maasai community has coexisted with the wildlife surrounding it for decades from Nairobi National Park, Maasai Mara and Amboseli. These parks border Maasai lands. Although the northern, eastern, and western perimeters of the Nairobi National Park are fenced, the southern part is not. It is at this point that the Maasai community’s land meets the park. This area also acts as a wildlife dispersal area where wildlife can freely migrate to other parks, including Maasai Mara and Amboseli. The park is only 117sq kms and its vitality depends on the plains to the south where the Maasai …


Whose Knowledge Counts?: Irrigation Development In Turkana, Kenya (1963-2019), G. L. Akall Oct 2021

Whose Knowledge Counts?: Irrigation Development In Turkana, Kenya (1963-2019), G. L. Akall

IGC Proceedings (1977-2023)

Irrigation has long been promoted in Africa’s drylands as a means to improve food security and livelihoods. Turkana County, one of the driest regions of Kenya, has a long history of irrigation interventions, extending from the colonial era to the present. The recent discovery of two huge water aquifers in the arid Turkana region, Kenya’s Vision 2030 and devolution has fed into enthusiasm for irrigation as an excellent solution to the multiple problems in the region against other activities like pastoralism. This is in spite of a history of failed irrigation developments in Turkana (Hogg 1987). This paper explores the …


Co-Produced Research Supports Pastoralists To Pursue Transformative Social And Ecological Change In Rangelands, R. S. Reid, K-A. S. Kassam, T. Pickering, A. Yasin, Chantsallkham Jamsranjav, Khishigbayar Jamiyansharav, Tungalag Ulambayar, Corrine N. Knapp Oct 2021

Co-Produced Research Supports Pastoralists To Pursue Transformative Social And Ecological Change In Rangelands, R. S. Reid, K-A. S. Kassam, T. Pickering, A. Yasin, Chantsallkham Jamsranjav, Khishigbayar Jamiyansharav, Tungalag Ulambayar, Corrine N. Knapp

IGC Proceedings (1977-2023)

Over the last two decades, pastoralists and researchers have formed powerful alliances to transform how we think about and do research-with-action in rangelands. These alliances promote faster learning about problems and their potential solutions by bringing together diverse partners and their different ways of understanding important issues. They also ensure research is fully relevant to real problems, so it supports pastoralists to act on both old and new issues that they face. While these approaches can be contentious when perspectives and experiences do not align, team members are finding them transformative, if they commit to working together over the long …


Land Use Planning For Resilient Pastoral Rangelands: Greater Serengeti Mara Ecosystem, Y. M. Said, B. J. Graae, M. Nielsen, H. P. Hartstean Oct 2021

Land Use Planning For Resilient Pastoral Rangelands: Greater Serengeti Mara Ecosystem, Y. M. Said, B. J. Graae, M. Nielsen, H. P. Hartstean

IGC Proceedings (1977-2023)

Greater Serengeti Mara Ecosystem (GSME) encompasses large protected areas of savanna with iconic wildlife surrounded by pastoralists and farms. GSME is facing severe pressure from human-induced changes due to rapid increase in population and climate variability. We undertook surveys with local communities to understand the potential impacts of these changes on wildlife and livelihoods of communities. We visited eight villages in Kenya and Tanzania and discussed with local communities and leaders, park management on drivers of change, and wishes for future development. To facilitate the conversation, we developed posters with four scenarios as a basis for discussions and a board …


Producing Useful Knowledge For Sustainable Development, K. A. Galvin Oct 2021

Producing Useful Knowledge For Sustainable Development, K. A. Galvin

IGC Proceedings (1977-2023)

Africa makes a relatively minor contribution to global greenhouse gas emissions compared with developed nations, yet the African continent will be increasingly vulnerable to climate change processes in the coming decades. Critical challenges include meeting basic needs for food, water, shelter, and other necessities without undermining biodiversity and ecosystem services. Coordination efforts to address multiple global change related stressors has generally occurred at the national level and taken an external approach, with national governments favoring collaboration with foreign-based NGOs and other international institutions. However, the involvement of actors at the local level correlates with decisions that are better adapted to …


Mega-Herbivores, Plants And Soils, Jennifer Adams Krumins Oct 2021

Mega-Herbivores, Plants And Soils, Jennifer Adams Krumins

Sustainability Seminar Series

Ecosystem and plant ecologists understand that herbivory can have a profound influence on primary production and plant community structure. This can be seen in mass outbreaks of insect herbivores or the grazing activity of ungulate herds. Likewise, the same ecologists understand that plants interact closely in a bidirectional relationship with soil organisms and the ecosystem properties they moderate. Therefore, logically we hypothesize that herbivory will have either a direct effect on soil communities and their functioning, or at minimum, an indirect effect on the soils via the plants they support. My sabbatical research included participation in multiple programs studying the …


A Clark-Ocone Type Formula Via Itô Calculus And Its Application To Finance, Takuji Arai, Ryoichi Suzuki Oct 2021

A Clark-Ocone Type Formula Via Itô Calculus And Its Application To Finance, Takuji Arai, Ryoichi Suzuki

Journal of Stochastic Analysis

No abstract provided.


Relationships Among Toilet Sharing, Water Source Locations, And Handwashing Places Without Observed Soap: A Cross-Sectional Study Of The Richest Households In Bangladesh, Mazbahul G. Ahamad, Mark Burbach, Fahian Tanin Oct 2021

Relationships Among Toilet Sharing, Water Source Locations, And Handwashing Places Without Observed Soap: A Cross-Sectional Study Of The Richest Households In Bangladesh, Mazbahul G. Ahamad, Mark Burbach, Fahian Tanin

School of Natural Resources: Faculty Publications

Background: A high percentage of the richest households in Bangladesh lack soap at their handwashing places, a problem that is typically considered to be one of the poor. Objective: We investigated toilet sharing practices, locations of water sources, and relevant sociodemographic factors associated with the observed handwashing places that lack soap in the richest (ninth wealth decile) households in Bangladesh. Methods: We used data from the 2017-18 Bangladesh Demographic and Health (BDHS) Survey. Logistic regression technique was used to investigate how toilet sharing practices, water source locations, and different sociodemographic factors were associated with observed handwashing places without soap. Results: …


Ferromagnetic Resonances In Single-Crystal Yttrium Iron Garnet Nanofilms Fabricated By Metal-Organic Decomposition, Szu Fan Wang, Kayetan Chorazewicz, Suvechhya Lamichhane, Ronald A. Parrott, Stefano Cabrini, Peter Fischer, Noah Kent, John H. Turner, Takayuki Ishibashi, Zachary Parker Frohock, Jacob J. Wisser, Peng Li, Ruthi Zielinski, Bryce Herrington, Yuri Suzuki, Mingzhong Wu, Keiko Munechika, Carlos Pina-Hernandez, Robert Streubel, Allen A. Sweet Oct 2021

Ferromagnetic Resonances In Single-Crystal Yttrium Iron Garnet Nanofilms Fabricated By Metal-Organic Decomposition, Szu Fan Wang, Kayetan Chorazewicz, Suvechhya Lamichhane, Ronald A. Parrott, Stefano Cabrini, Peter Fischer, Noah Kent, John H. Turner, Takayuki Ishibashi, Zachary Parker Frohock, Jacob J. Wisser, Peng Li, Ruthi Zielinski, Bryce Herrington, Yuri Suzuki, Mingzhong Wu, Keiko Munechika, Carlos Pina-Hernandez, Robert Streubel, Allen A. Sweet

Robert Streubel Papers

Tunable microwave and millimeter wave oscillators and bandpass filters with ultra-low phase noise play a critical role in electronic devices, including wireless communication, microelectronics, and quantum computing. Magnetic materials, such as yttrium iron garnet (YIG), possess ultra-low phase noise and a ferromagnetic resonance tunable up to tens of gigahertz. Here, we report structural and magnetic properties of single-crystal 60 and 130 nm-thick YIG films prepared by metal-organic decomposition epitaxy. These films, consisting of multiple homoepitaxially grown monolayers, are atomically flat and possess magnetic properties similar to those grown with liquid-phase epitaxy, pulsed laser deposition, and sputtering. Our approach does not …


Structural And Morphological Properties Of Wool Keratin And Cellulose Biocomposites Fabricated Using Ionic Liquids, Karleena Rybacki, Stacy A. Love, Bailey Blessing, Abneris Morales, Emily Mcdermott, Kaylyn Cai, Xiao Hu, David Salas-De La Cruz Oct 2021

Structural And Morphological Properties Of Wool Keratin And Cellulose Biocomposites Fabricated Using Ionic Liquids, Karleena Rybacki, Stacy A. Love, Bailey Blessing, Abneris Morales, Emily Mcdermott, Kaylyn Cai, Xiao Hu, David Salas-De La Cruz

College of Science & Mathematics Departmental Research

In this study, the structural, thermal, and morphological properties of biocomposite films composed of wool keratin mixed with cellulose and regenerated with ionic liquids and various coagulation agents were characterized and explored. These blended films exhibit different physical and thermal properties based on the polymer ratio and coagulation agent type in the fabrication process. Thus, understanding their structure and molecular interaction will enable an understanding of how the crystallinity of cellulose can be modified in order to understand the formation of protein secondary structures. The thermal, morphological, and physiochemical properties of the biocomposites were investigated by Fourier transform infrared (FTIR) …


Mine Water Drainage Pollution In China's Coal Mining Areas And The Construction Of Prevention And Control Technical System, Sun Yajun, Xu Zhimin, Li Xin, Zhang Li, Chen Ge, Zhao Xianming, Gao Yating, Liu Qi, Zhang Shangguo, Wang Weijun, Zhu Lulu, Wang Sheng Oct 2021

Mine Water Drainage Pollution In China's Coal Mining Areas And The Construction Of Prevention And Control Technical System, Sun Yajun, Xu Zhimin, Li Xin, Zhang Li, Chen Ge, Zhao Xianming, Gao Yating, Liu Qi, Zhang Shangguo, Wang Weijun, Zhu Lulu, Wang Sheng

Coal Geology & Exploration

Mining activities are bound to produce enormous mine water drainage. Mine water in China shows relatively poor water quality and high cost of water treatment and other problems. Firstly, the main characteristics of mine water quality in China's typical mine areas are clarified in this paper: conventional ions are the main chemical components causing poor mine water quality; mine water has a small proportion of toxic and harmful substances, which is generally better than the quality standard of class Ⅲ groundwater. Secondly, some scientific issues on the formation and evolution of mine water quality are discussed in detail, including the …


Gas Emission-Based Determination Of The Reasonable Driving Speed In Coal Roadway, Fu Shuai, Si Qingmin, Wang Qifei, Guo Xinyao, Zhang Hongtu Oct 2021

Gas Emission-Based Determination Of The Reasonable Driving Speed In Coal Roadway, Fu Shuai, Si Qingmin, Wang Qifei, Guo Xinyao, Zhang Hongtu

Coal Geology & Exploration

Scientific determination of the tunneling speed is an important prerequisite for the safe and efficient production in coal mines with high gas and outburst. In order to determine the reasonable driving speed of coal roadway and reduce the occurrence of dynamic disasters in coal roadway driving, the distribution law of gas in roadway head was analyzed, the mathematical model was established. Gas emission characteristics were also analyzed at different driving speeds based on the model. Taking Jinhui Wanfeng Coal Mine as an example, the reasonable driving speed was determined in this coal mine based on its gas emission characteristics. Results …


Discussion On Overburden Zoning Model After Mining And Its Engineering Significance, Lyu Yuguang, Qiao Wei, Cheng Jianyuan, Cui Ping Oct 2021

Discussion On Overburden Zoning Model After Mining And Its Engineering Significance, Lyu Yuguang, Qiao Wei, Cheng Jianyuan, Cui Ping

Coal Geology & Exploration

The mechanical state of overburden after mining is directly related to roof accidents and roof water disasters, so it is necessary to study the overburden structure after mining. The "New Four Zones" model of overburden structure is proposed: caving zone, fracture zone, bedrock separation zone and loose alluvium zone. Combined with the previous "Three Zones" model and "Four Zones" model, this paper makes a spatial comparative analysis to clarify the spatial relationship of the three zoning models. It discusses the scientific nature of the "New Four Zones" model in terms of the influence of mining on water level of the …


Statistical Regularity Of Physical And Mechanical Indexes Of Secondary Red Clay In Chenggong District, Kunming, Gao Haiyan, Zhang Jiaming Oct 2021

Statistical Regularity Of Physical And Mechanical Indexes Of Secondary Red Clay In Chenggong District, Kunming, Gao Haiyan, Zhang Jiaming

Coal Geology & Exploration

In order to analyze the statistical regularity of physical and mechanical indexes of secondary red clay in Chenggong District, Kunming, the index data of 275 groups of secondary red clay samples from 69 geotechnical investigation boreholes in Wujiaying area of Chenggong are taken as the research object. Based on the statistical analysis principle, the variation range, average value, standard deviation, coefficient of variation of 13 indexes and the correlation between indexes and depth are analyzed by SPSS statistical analysis software, and the physical and mechanical properties of secondary red clay are summarized. Then, the linear empirical formula between indexes is …