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2019

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Articles 151 - 180 of 13031

Full-Text Articles in Physical Sciences and Mathematics

Effects Of Storage Conditions On Endophyte And Seed Viability In Pasture Grasses, David E. Hume, Stuart D. Card, M. Philip Rolston Dec 2019

Effects Of Storage Conditions On Endophyte And Seed Viability In Pasture Grasses, David E. Hume, Stuart D. Card, M. Philip Rolston

IGC Proceedings (1977-2023)

Several important temperate pasture grasses have co-evolved with mutualistic Epichloë fungal endophytes. These endophytes impart beneficial attributes to their host as they enhance the fitness of the grass when under biotic and abiotic stresses. The asexual species of these fungi (formerly classed as Neotyphodium) are obligate symbionts, and efficiently colonise newly formed tillers and infect seed by direct colonisation of the embryo. These endophytes are strictly seed transmitted. Survival of the fungus in this seed is therefore critical for the dissemination of endophyte-infected seed to grassland farmers. Longevity of endophyte in stored seed is primarily determined by the length …

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Managing Seed Dormancy In Forage Legumes And Grasses: An Update, Yanrong Wang, Xiaowen Hu Dec 2019

Managing Seed Dormancy In Forage Legumes And Grasses: An Update, Yanrong Wang, Xiaowen Hu

IGC Proceedings (1977-2023)

Seed dormancy is a common feature of the majority of forage species. It usually causes problems both to the grower and the seed analyst. Many methods have been developed to break dormant seed over the time, and efficacy of a method usually varies with species and cultivars. The objective of this paper is to review and summarise important methods used for seed dormancy breaking in forage legume and grass species, and the mechanisms involved.

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Restoring North America’S Sagebrush Steppe Ecosystem Using Seed Enhancement Technologies, Matthew D. Madsen, Kirk W. Davies, Chad S. Boyd, Jay D. Kerby, Daniel L. Carter, Tony J. Svejcar Dec 2019

Restoring North America’S Sagebrush Steppe Ecosystem Using Seed Enhancement Technologies, Matthew D. Madsen, Kirk W. Davies, Chad S. Boyd, Jay D. Kerby, Daniel L. Carter, Tony J. Svejcar

IGC Proceedings (1977-2023)

Rangelands occupy over a third of global land area, and in many cases are in less than optimum condition as a result of past land use, catastrophic wildfire and other disturbance, invasive species, or climate change. Often the only means of restoring these lands involves seeding desirable species, yet there are few cost effective seeding technologies, especially for the more arid rangeland types. The inability to consistently establish desired plants from seed may indicate that the seeding technologies being used are not successful in addressing the primary sources of mortality in the progression from seed to established plant. Seed enhancement …

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Comprehensive Evaluation Of Wild Elymus L. Germplasm In Inner Mongolia, Juan Qi, Wen-Xia Cao, Ting Jiao, Xiao-Peng Pu, Wei-Hong Yan Dec 2019

Comprehensive Evaluation Of Wild Elymus L. Germplasm In Inner Mongolia, Juan Qi, Wen-Xia Cao, Ting Jiao, Xiao-Peng Pu, Wei-Hong Yan

IGC Proceedings (1977-2023)

Grassland degradation is increasing in severity and is an important global issue in the 21st century. Increasing research is being conducted on how to solve these problems (Niu and Jiang 2004). Restoration and revegetation of degraded grassland and the establishment of artificial pastures are important in addressing degradation. Successful restoration requires the identification of species and seed sources that are adapted to the ecological conditions of the restoration site. Elymus L. is a large genus that contains about 150 species distributed across a wide range of ecological sites across temperate and subtropical regions of the world (Dewey 1984; Love 1984). …

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Fatty Acid Analysis Of The Transgenic Tobacco Expressing A Delta 6-Desaturase Gene From Microula Sikkimensis, Shujuan Wu, Lijing Zhang, Xiaolong Chen, Xiumei Miao, Decao Niu, Hua Fu Dec 2019

Fatty Acid Analysis Of The Transgenic Tobacco Expressing A Delta 6-Desaturase Gene From Microula Sikkimensis, Shujuan Wu, Lijing Zhang, Xiaolong Chen, Xiumei Miao, Decao Niu, Hua Fu

IGC Proceedings (1977-2023)

γ-Linolenic acid (GLA, 18:3Δ6, 9, 12) and octadecatetraenoic acid (OTA, 18:4Δ6, 9, 12, 15) are important polyunsaturated fatty acids (PUFAs), which have been proved to be benefit for human health (Fan and Chapkin 1998; Whelan 2009). Currently, fish are the predominant source of PUFAs. However, with the growth of world’s population and the more nutrition requirements, fishery resources are shrinking. Alternative sources of PUFAs are being investigated (Truksa et al. 2009). The major oil crops do not contain GLA and OTA, only several plant species contain these important fatty acids in their leaf lipids and …

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Production Of Giant Panicum In Contrasting Environments In Semi-Arid Kenya, Donald M. G. Njarui, Mwangi Gatheru, David Miano Mwangi, George A. Keya Dec 2019

Production Of Giant Panicum In Contrasting Environments In Semi-Arid Kenya, Donald M. G. Njarui, Mwangi Gatheru, David Miano Mwangi, George A. Keya

IGC Proceedings (1977-2023)

Giant panicum (Panicum maximum Jacq.) is a tall, vigorous perennial grass that is native to tropical and sub-tropical Africa. It is drought tolerant due to its deep and dense fibrous roots system and grows in a wide range of soil types. It is an important livestock feed and has been extensively cultivated in Brazil (Santos et al. 2006). Despite its wide genetic diversity in East Africa, its potential for livestock feed has not been exploited there due to limited research. Our research was aimed at evaluating the production of several giant panicum ecotypes in contrasting environments in semi-arid …

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Controlling Lethal Browning Of Hemarthria Compressa Tissue Cultures, Chunhua Yang, Yaohua Xu, Lingzhi Chen, Yifang Sui Dec 2019

Controlling Lethal Browning Of Hemarthria Compressa Tissue Cultures, Chunhua Yang, Yaohua Xu, Lingzhi Chen, Yifang Sui

IGC Proceedings (1977-2023)

Hemarthria compressa is an important warm-season forage grass for use in Southwest China. However, due to poor seed set, it is propagated by vegetative cuttings of stolons, rhizomes, and nodal sections. The in vitro propagation of H. compressa is still faced with difficulties including blackening or browning of tissues prior to culturing due to the oxidation of phenolic compounds by polyphenolic oxidase enzyme present in excised tissue (Yang et al. 2008). The objectives of the study were to investigate possible means of successful initiation of cultures through elimination of phenolic browning.

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Leaf Growth And Senescence Rates In Brown-Back Wallaby Grass, Rytidosperma Duttonianum, Helen G. Daily, Shaun Lisson, Kerry L. Bridle, Peter A. Lane, Stuart Anderson, Ross Corkrey Dec 2019

Leaf Growth And Senescence Rates In Brown-Back Wallaby Grass, Rytidosperma Duttonianum, Helen G. Daily, Shaun Lisson, Kerry L. Bridle, Peter A. Lane, Stuart Anderson, Ross Corkrey

IGC Proceedings (1977-2023)

Knowledge of leaf turnover in grasses is necessary to model curing (the accumulation of dead material in the sward), which is not well represented in current pasture growth models, nor for many Australian native species. Leaf turnover begins with the appearance of successive leaves, which elongate until typically, a leaf ligule develops to indicate a mature, fully expanded length. Green leaf life span extends from appearance to the beginning of senescence, which ultimately leads to death (Fig. 1). Here, the individual rates of leaf growth and senescence for the Australian native brown-back wallaby grass, Rytidosperma duttonianum (Cashmore) Connor & Edgar, …

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Basin Wildrye (Leymus Cinereus) Pooled Tetraploid Accessions For U.S. Intermountain West Rangeland Reclamation, Stanford A. Young, Jason Vernon, Nancy Shaw Dec 2019

Basin Wildrye (Leymus Cinereus) Pooled Tetraploid Accessions For U.S. Intermountain West Rangeland Reclamation, Stanford A. Young, Jason Vernon, Nancy Shaw

IGC Proceedings (1977-2023)

Basin wildrye (Leymus cinereus [Scribn. & Merr.] Á. Löve) is an important perennial, hardy, long-lived, cool season C3 native grass of rangeland plant communities throughout much of western United States and Canada. All classes of livestock and wildlife, including large and small birds and mammals, utilise the grass year round for food and protection due to its 2-3 m tall, stiff stature which provides standing winter cover. Though occurring in precipitation areas of 150-500 mm and elevations of 600 to 3,000 m, it is usually found in deep, well-drained soils of high water holding capacity along drainage areas. Seedling …

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Summer Dormancy Expression In The Australian Native Grass Elymus Scaber, Matthew Newell, Richard C. Hayes, Jim Virgona, Philip Larkin Dec 2019

Summer Dormancy Expression In The Australian Native Grass Elymus Scaber, Matthew Newell, Richard C. Hayes, Jim Virgona, Philip Larkin

IGC Proceedings (1977-2023)

Complete summer dormancy is associated with plant senescence in late spring-summer even though soil moisture is non-limiting. The trait is well understood in exotic temperate grasses for persistence in environments which experience frequent summer droughts (Annicchiarico et al. 2011). However, the trait appears to be uncommon in Australian native grasses (Culvenor 2009). The C3 native perennial grass, Elymus scaber, is broadly adapted across a wide range of climatic zones and soil types in south eastern Australia (Johnston et al. 2001) and has been described as displaying strong summer dormancy (Mitchell et al. 2001). However, the reports …

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Challenges To Domesticating "Native" Forage Legumes, James P. Muir, José C. B. Dubeux Jr., Mércia V. F. Dos Santos, Inacio C. Maposse, William D. Pitman, Twain J. Butler Dec 2019

Challenges To Domesticating "Native" Forage Legumes, James P. Muir, José C. B. Dubeux Jr., Mércia V. F. Dos Santos, Inacio C. Maposse, William D. Pitman, Twain J. Butler

IGC Proceedings (1977-2023)

If ruminant production from cultivated and natural grasslands is to depend less on petroleum-based products, forage legumes must serve as protein sources. Commercially available legumes for warm-dry climate grasslands are, however, very limited and resources available for developing such legumes are inadequate. Indeterminate flowering and dehiscent seed pods combined with the need for specialized seed harvesting equipment are major impediments (Butler and Muir 2012). Warm climates often present environmental challenges such as poor rainfall distribution, extended dry seasons, temperature extremes and aggressive grass species (Muir et al. 2011). Erosion of indigenous knowledge and replacement with inappropriate land management approaches …

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Row Spacing Effects On Biomass Components And Accumulated Energy In Elymus Sibiricus L., Jinping Liu, Minghong You Dec 2019

Row Spacing Effects On Biomass Components And Accumulated Energy In Elymus Sibiricus L., Jinping Liu, Minghong You

IGC Proceedings (1977-2023)

Elymus sibiricus L. is widely distributed in the eastern Tibetan Plateau of China. Current research on E. sibiricus mainly focuses on resource assessment, breeding, cultivation and dynamics of forage yield. Little is known about the effects of row spacing on the biomass components and accumulated energy of E. sibiricus. We conducted a study to determine the effects of row spacing on biomass components and accumulated energy in E. sibiricus. These data are important to optimize forage and seed production of E. sibiricus, and can assist in developing animal husbandry, structurally adjusting the agricultural industry and protecting the …

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Seeding Rate And Row-Spacing Effects On Seed Yield And Yield Components Of Leymus Chinensis (Trin.) Tzvel., Yunhua Han, Xianguo Wang, Tianming Hu, Zhenlei Zhu, Zhengwei Wang, Ying Wang Dec 2019

Seeding Rate And Row-Spacing Effects On Seed Yield And Yield Components Of Leymus Chinensis (Trin.) Tzvel., Yunhua Han, Xianguo Wang, Tianming Hu, Zhenlei Zhu, Zhengwei Wang, Ying Wang

IGC Proceedings (1977-2023)

Chinese sheepgrass (Leymus chinensis (Trin.) Tzvel.) is widely distributed in the eastern portion of the Inner Mongolian Plateau and the Songnen Grassland of China. This grass is highly salt, cold and drought tolerant and has been the major source of forage for cows and other ruminants in China (Gao et al. 2012). Seed yield of this grass is very low under native conditions because of the low heading percentage and percentage of seed set (Wang et al. 2010). The Hexi Corridor, located in China’s northwestern Gansu Province, is the seed production center of China because of its …

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Using Common Gardens And Aflp Analyses To Identify Metapopulations Of Indigenous Plant Materials For Rangeland Revegetation In Western Usa, Douglas A. Johnson, B. Shaun Bushman, Thomas A. Jones, Kishor Bhattarai Dec 2019

Using Common Gardens And Aflp Analyses To Identify Metapopulations Of Indigenous Plant Materials For Rangeland Revegetation In Western Usa, Douglas A. Johnson, B. Shaun Bushman, Thomas A. Jones, Kishor Bhattarai

IGC Proceedings (1977-2023)

Past mismanagement, overgrazing, invasive weedy species, wildfires, marginal crop production, mineral and energy extraction, recreation and global climate change are challenges currently facing rangelands (Pierson et al. 2011). These disturbances may lead to long-term reductions in biodiversity, altered nutrient and water cycling, diminished forage production for livestock and wildlife, increased wildfire frequency and increased soil erosion and stream sedimentation (Sheley et al. 2008). Rangeland revegetation with desirable plant materials may be required to improve degraded conditions, speed recovery, and prevent further erosion and degradation. There is a critical need for plant materials to restore and revegetate rangeland ecosystems. …

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Seed Rain Of A Native Pasture Under A Range Of Grazing And Fertiliser Regimes, Zhongnan Nie, Reto Zollinger Dec 2019

Seed Rain Of A Native Pasture Under A Range Of Grazing And Fertiliser Regimes, Zhongnan Nie, Reto Zollinger

IGC Proceedings (1977-2023)

In recent years, deferred grazing (no defoliation of pastures for a period generally from spring to late summer or autumn) has been widely adopted to rejuvenate degraded native pastures in marginal land classes such as steep hill country in western Victoria, Australia. One of the important features of deferred grazing is the increase of seed production over summer and autumn, which could potentially lead to natural regeneration and improved groundcover by pasture plants (Nie et al. 1999). While increasing seed numbers in the soil seed bank following deferred grazing were reported (Nie and Mitchell 2006), there has been little …

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Genetic Variation And Geographical Differentiation Of Elymus Nutans (Poaceae: Triticeae) From West China, Shiyong Chen, Xinquan Zhang, Xiao Ma, Jiamin Miao Dec 2019

Genetic Variation And Geographical Differentiation Of Elymus Nutans (Poaceae: Triticeae) From West China, Shiyong Chen, Xinquan Zhang, Xiao Ma, Jiamin Miao

IGC Proceedings (1977-2023)

Elymus nutans Griseb. is not only an important alpine forage grass, but also as a crucial gene pool for improving cereal crops. Understanding and maintaining the genetic diversity of the species are essential for both conservation strategy and breeding programs. However, little is known about its genetic and geographical differentiation patterns. E. nutans is a perennial, caespitose and allohexaploid (2n=6x=42) species that contains the St, H and Y genomes. It is native to temperate and tropical Asia, ranging from western and central Asia in the west to China and Mongolia in the east, from Russia in the north to India …

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Seed Ecology Of Microlaena Stipoides In Grazing Systems Of South-Eastern Australia, Meredith L. Mitchell, James M. Virgona, Joe Jacobs, David R. Kemp Dec 2019

Seed Ecology Of Microlaena Stipoides In Grazing Systems Of South-Eastern Australia, Meredith L. Mitchell, James M. Virgona, Joe Jacobs, David R. Kemp

IGC Proceedings (1977-2023)

Microlaena stipoides var. stipoides (Labill.) R.Br. (Microlaena) is a tufted C3 native Australian perennial grass with a short rhizome that can form dense lawns. Microlaena has a wide geographic distribution throughout southern Australia, particularly in the temperate, high-rainfall tableland areas (> 550 mm AAR) of south-eastern and western Australia where is considered to be important for the grazing industries because of its extended growing season in higher rainfall areas, persistence over many years and persistence through drought. Although Microlaena has an important role in the stability of grazed native pastures, little is known about this grass in grazed communities. This …

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Technical Challenges In Evaluating Southern China’S Forage Germplasm Resources, Changjun Bai, Guodao Liu, Yu Zhang, Daogeng Yu Dec 2019

Technical Challenges In Evaluating Southern China’S Forage Germplasm Resources, Changjun Bai, Guodao Liu, Yu Zhang, Daogeng Yu

IGC Proceedings (1977-2023)

The present status of the collection, conservation and utilisation of the pasture germplasm in tropical and subtropical zones in China is reviewed. The Tropical Pasture Research Centre (TPRC) of Chinese Academy of Tropical Agricultural Sciences (CATAS) has been engaged in this research since the 1940s. A low temperature gene bank, an in vitro plant library and a nursery station have been established. In total, 5890 indigenous fodder materials belonging to 478 species, 161 genera and 12 families have been surveyed and collected in South China; 1130 exotic materials belonging to 87 species, 42 genera of grasses and legumes have been …

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World Interest In Diverse Native Plant Stands, Michael P. Schellenberg, Bili Biligetu, Eric G. Lamb, Jenalee M. Mischkolz Dec 2019

World Interest In Diverse Native Plant Stands, Michael P. Schellenberg, Bili Biligetu, Eric G. Lamb, Jenalee M. Mischkolz

IGC Proceedings (1977-2023)

The objective of this paper was to provide a brief overview of native plant use and development including examples of native plant research being conducted in Canada. There is increasing interest in native plants in various countries. Currently, native plants are used in reclamation, biomass biofuel production, forage seeding, habitat restoration, and water and soil conservation efforts. Many countries have active programs for native plant preservation and new germplasm development, but seed cost, seed quality, and ease of establishment are still challenges for large-scale use. Many improved native plant germplasms have been released in recent years. In some countries, legislation …

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The Values Of Warm-Season Native Perennial Grasses Grown For Pasture Or Biofuel In The Southern Great Plains, Usa, James K. Rogers, Bryan Nichols, Jon T. Biermacher, Jagadeesh Mosali Dec 2019

The Values Of Warm-Season Native Perennial Grasses Grown For Pasture Or Biofuel In The Southern Great Plains, Usa, James K. Rogers, Bryan Nichols, Jon T. Biermacher, Jagadeesh Mosali

IGC Proceedings (1977-2023)

The Renewable Fuel Standard under the Energy Independence and Security Act of 2007 mandated the production of 136 billion liters of cellulosic biofuel by 2022. Switchgrass (Panicum virgatum) has been identified as a primary feedstock because it is a perennial, produces high yields and is adapted to a wide environmental range. Development of the cellulosic biofuel industry has been slow. A reason for this slow development is lack of available feedstock driven by lack of a developed market. Rather than considering switchgrass only as a dedicated biofuel feedstock, we examined its potential both for grazing and biofuel feedstock. …

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(Cyclopentadienone)Iron-Catalyzed Transfer Dehydrogenation Of Symmetrical And Unsymmetrical Diols To Lactones, Yidan Tang, Rowan I.L. Meador, Casina T. Malinchak, Emily E. Harrison, Kimberly A. Mccaskey, Melanie C. Hempel, Timothy W. Funk Dec 2019

(Cyclopentadienone)Iron-Catalyzed Transfer Dehydrogenation Of Symmetrical And Unsymmetrical Diols To Lactones, Yidan Tang, Rowan I.L. Meador, Casina T. Malinchak, Emily E. Harrison, Kimberly A. Mccaskey, Melanie C. Hempel, Timothy W. Funk

Chemistry Faculty Publications

Air-stable iron carbonyl compounds bearing cyclopentadienone ligands with varying substitution were explored as catalysts in dehydrogenative diol lactonization reactions using acetone as both the solvent and hydrogen acceptor. Two catalysts with trimethylsilyl groups in the 2- and 5-positions, [2,5-(SiMe3)2-3,4-(CH2)4(η4-C4C═O)]Fe(CO)3 (1) and [2,5-(SiMe3)2-3,4-(CH2)3(η4-C4C═O)]Fe(CO)3 (2), were found to be the most active, with 2 being the most selective in the lactonization of diols containing both primary and secondary alcohols. Lactones containing five-, six-, and seven-membered rings were successfully synthesized, and no over-oxidations to carboxylic acids were detected. The lactonization of unsymmetrical diols containing two …

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First-Principles Study Of High-Pressure Phase Stability And Superconductivity Of Bi4i4, Shiyu Deng, Xianqi Song, Quan Li, Yu Xie, Changfeng Chen, Yanming Ma Dec 2019

First-Principles Study Of High-Pressure Phase Stability And Superconductivity Of Bi4i4, Shiyu Deng, Xianqi Song, Quan Li, Yu Xie, Changfeng Chen, Yanming Ma

Physics & Astronomy Faculty Research

Bismuth iodide Bi4I4 exhibits intricate crystal structures and topological insulating states that are highly susceptible to influence by environments, making its physical properties highly tunable by external conditions. In this work, we study the evolution of structural and electronic properties of Bi4I4 at high pressure using an advanced structure search method in conjunction with first-principles calculations. Our results indicate that the most stable ambient-pressure monoclinic α−Bi4I4 phase in C2/m symmetry transforms to a trigonal P31c structure (ɛ−Bi4I4) at 8.4 GPa, then to a tetragonal P4/mmm structure (ζ−Bi4I4) above 16.6 GPa. In contrast to the semiconducting nature of ambient-pressure Bi4I4, the …

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Optimizing Measurement Strengths For Qubit Quasiprobabilities Behind Out-Of-Time-Ordered Correlators, Razieh Mohseninia, José Raúl González Alonso, Justin Dressel Dec 2019

Optimizing Measurement Strengths For Qubit Quasiprobabilities Behind Out-Of-Time-Ordered Correlators, Razieh Mohseninia, José Raúl González Alonso, Justin Dressel

Mathematics, Physics, and Computer Science Faculty Articles and Research

Out-of-time-ordered correlators (OTOCs) have been proposed as a tool to witness quantum information scrambling in many-body system dynamics. These correlators can be understood as averages over nonclassical multitime quasiprobability distributions (QPDs). These QPDs have more information and their nonclassical features witness quantum information scrambling in a more nuanced way. However, their high dimensionality and nonclassicality make QPDs challenging to measure experimentally. We focus on the topical case of a many-qubit system and show how to obtain such a QPD in the laboratory using circuits with three and four sequential measurements. Averaging distinct values over the same measured distribution reveals either …

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Protein And Polysaccharide-Based Magnetic Composite Materials For Medical Applications., Elizabeth J Bealer, Kyril Kavetsky, Sierra Dutko, Samuel Lofland, Xiao Hu Dec 2019

Protein And Polysaccharide-Based Magnetic Composite Materials For Medical Applications., Elizabeth J Bealer, Kyril Kavetsky, Sierra Dutko, Samuel Lofland, Xiao Hu

College of Science & Mathematics Departmental Research

The combination of protein and polysaccharides with magnetic materials has been implemented in biomedical applications for decades. Proteins such as silk, collagen, and elastin and polysaccharides such as chitosan, cellulose, and alginate have been heavily used in composite biomaterials. The wide diversity in the structure of the materials including their primary monomer/amino acid sequences allow for tunable properties. Various types of these composites are highly regarded due to their biocompatible, thermal, and mechanical properties while retaining their biological characteristics. This review provides information on protein and polysaccharide materials combined with magnetic elements in the biomedical space showcasing the materials used, …

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Generating Energy Data For Machine Learning With Recurrent Generative Adversarial Networks, Mohammad Navid Fekri, Ananda M. Ghosh, Katarina Grolinger Dec 2019

Generating Energy Data For Machine Learning With Recurrent Generative Adversarial Networks, Mohammad Navid Fekri, Ananda M. Ghosh, Katarina Grolinger

Electrical and Computer Engineering Publications

The smart grid employs computing and communication technologies to embed intelligence into the power grid and, consequently, make the grid more efficient. Machine learning (ML) has been applied for tasks that are important for smart grid operation including energy consumption and generation forecasting, anomaly detection, and state estimation. These ML solutions commonly require sufficient historical data; however, this data is often not readily available because of reasons such as data collection costs and concerns regarding security and privacy. This paper introduces a recurrent generative adversarial network (R-GAN) for generating realistic energy consumption data by learning from real data. Generativea adversarial …

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An Analysis Of The Atmospheric Propagation Of Underground-Explosion-Generated Infrasonic Waves Based On The Equations Of Fluid Dynamics: Ground Recordings, Roberto Sabatini, Jonathan B. Snively, Michael P. Hickey, J. L. Garrison Dec 2019

An Analysis Of The Atmospheric Propagation Of Underground-Explosion-Generated Infrasonic Waves Based On The Equations Of Fluid Dynamics: Ground Recordings, Roberto Sabatini, Jonathan B. Snively, Michael P. Hickey, J. L. Garrison

Publications

An investigation on the propagation of underground-explosion-generated infrasonic waves is carried out via numerical simulations of the equations of fluid dynamics. More specifically, the continuity, momentum, and energy conservation equations are solved along with the Herzfeld-Rice equations in order to take into account the effects of vibrational relaxation phenomena. The radiation of acoustic energy by the ground motion caused by underground explosions is initiated by enforcing the equality, at ground level, between the component of the air velocity normal to the Earth's surface and the normal velocity of the ground layer. The velocity of the ground layer is defined semi-empirically …

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Microscopic Fabric Characteristics Of Typical Red Soft Rock In Badong Formation Under Uniaxial Compression Test, Xiao Zunqun, Wang Xin, Tang Dongsang, Dong Qiongying, Jiang Yinan, Yang Kai, Cao Tongtong, Deng Zhen Dec 2019

Microscopic Fabric Characteristics Of Typical Red Soft Rock In Badong Formation Under Uniaxial Compression Test, Xiao Zunqun, Wang Xin, Tang Dongsang, Dong Qiongying, Jiang Yinan, Yang Kai, Cao Tongtong, Deng Zhen

Coal Geology & Exploration

Red silty mudstone and argillaceous siltstone are the representatives of special rock and soil in Badong Formation, are easy to disintegrate when encountering water. According to the uniaxial compression test of rock samples, a numerical model of medium and soft rock uniaxial compression test was established based on PFC2D program. With the characteristics of stress-strain curve, subsection quantitative parameter calibration method was used to calibrate the microscopic parameters of soft rock samples. The adjustment method and the ratio of tangential bond strength(σc/τc) control specimen under uniaxial compression failure mode. The uniaxial compression test of silty …

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Analysis Of Suitable Development Technology Of Cbm(Gas) In Guizhou, Xu Xiaoqian, Meng Yingfang, Duan Zhengpeng, Li Guohong, Li Qingsong Dec 2019

Analysis Of Suitable Development Technology Of Cbm(Gas) In Guizhou, Xu Xiaoqian, Meng Yingfang, Duan Zhengpeng, Li Guohong, Li Qingsong

Coal Geology & Exploration

In recent years, technical bottlenecks have been encountered in the practice of CBM exploration and development in Guizhou Province, selecting suitable development technology is one of the key issues. Based on the background that CBM exists in thin coal seams and geological structures are complicated in Guizhou, combined with successful development and utilization of CBM, the CBM development and utilization technology suitable for complex geological conditions in Guizhou was put forward. Air drilling is recommended for drilling in Guizhou, according to different distance of thin seams, such as optical casing composite fracturing and salvageable bridge plug fracturing can be used. …

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Key Technology Of Drilling In-Seam Directional Borehole Of 3 000 M In Underground Coal Mine, Shi Zhijun, Dong Shuning, Yang Junzhe, Xu Chao, Hao Shijun, Li Quanxin, Chen Dianfu, Yao Ke, Liu Jianlin, Tian Dongzhuang Dec 2019

Key Technology Of Drilling In-Seam Directional Borehole Of 3 000 M In Underground Coal Mine, Shi Zhijun, Dong Shuning, Yang Junzhe, Xu Chao, Hao Shijun, Li Quanxin, Chen Dianfu, Yao Ke, Liu Jianlin, Tian Dongzhuang

Coal Geology & Exploration

The pre-mining gas governance mode in Baode coal mine requires that long directional borehole of more than 3 000 m can be drilled along coal seam. In view of the existing technology and equipment, there are technical problems in the construction of ultra-long directional borehole, such as the difficulty of sliding drilling, the large hydraulic pressure consumption in inlet waterway, the limited transmission distance of wireline MWD signal, and incapability of flushing liquid recycle. The technology of friction reduction in sliding drilling based on the hydraulic thrust of DHM and the torsion penetration of the ultra-long drilling tool, the technology …

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Extension Model Of Fracturing Cracks Of Translayer Horizontal Well In Roof Of Soft Coal Reservoir, Wang Zhirong, Hu Kai, Yang Jie, Chen Lingxia Dec 2019

Extension Model Of Fracturing Cracks Of Translayer Horizontal Well In Roof Of Soft Coal Reservoir, Wang Zhirong, Hu Kai, Yang Jie, Chen Lingxia

Coal Geology & Exploration

In order to study the propagation rules of hydraulic fracturing crack formed by a horizontal well in roof to coal seam, taking the Permian-Carboniferous coal field in North China as an example, through the classical theory of fracture mechanics, damage mechanics and fluid mechanics, combined with field actual data, the modeling and verification of the space-time evolution law of the crack propagation distance and fracturing time were carried out. Firstly, considering the additional stress of perforation, the characteristics of primary fracture and the permeability characteristics of rock formation, the calculation formula of cracking pressure of vertical hydraulic fracture caused by …

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