The purpose of this paper is to explore the promise of utilizing some relatively new feedback control techniques in ecosystem management. First, we set forth a basic ecological-economic model of a predator-prey-huntin...The purpose of this paper is to explore the promise of utilizing some relatively new feedback control techniques in ecosystem management. First, we set forth a basic ecological-economic model of a predator-prey-hunting system in which both the predator and prey have use(flow) and non-use(stock) value and when the predator can inflict transboundary damages. We then use new data from the US Mountain West to show how a particular feedback approach—linear parameter-varying(LPV) control—can be utilized in this context. Our LPV model is able to quantify the cost of managing disturbances that inevitably arise as a manager tries to keep the actual path of the system "close" to its optimum. The results suggest management strategies in mountain ecosystems that feature large, mammalian carnivores.展开更多
Methods of improving seismic event locations were investigated as part of a research study aimed at reducing ground control safety hazards. Seismic event waveforms collected with a 23-station three-dimensional sensor ...Methods of improving seismic event locations were investigated as part of a research study aimed at reducing ground control safety hazards. Seismic event waveforms collected with a 23-station three-dimensional sensor array during longwall coal mining provide the data set used in the analyses. A spatially variable seismic velocity model is constructed using seismic event sources in a passive tomographic method. The resulting three-dimensional velocity model is used to relocate seismic event positions. An evolutionary optimization algorithm is implemented and used in both the velocity model development and in seeking improved event location solutions. Results obtained using the different velocity models are compared. The combination of the tomographic velocity model development and evolutionary search algorithm provides improvement to the event locations.展开更多
This paper seeks to enhance the understanding that the horizontal stresses build up and release during coal pillar loading and unloading(post-failure) drawing upon three decades of observations, geomechanical monitori...This paper seeks to enhance the understanding that the horizontal stresses build up and release during coal pillar loading and unloading(post-failure) drawing upon three decades of observations, geomechanical monitoring and numerical modeling in bump-prone U.S. mines. The focus is on induced horizontal stress in mine pillars and surrounding strata as highly stressed pillars punch into the roof and floor, causing shear failure and buckling of strata; under stiff stratigraphic units of some western US mines, these events could be accompanied by violent failure of pillar cores. Pillar punching eventually results in tensile stresses at the base of the pillar, facilitating transition into the post-failure regime; this transition will be nonviolent if certain conditions are met, notably the presence of interbedded mudstones with low shear strength properties and proper mine designs for controlling seismicity and dynamic loads. The study clearly shows high confining stress build-up in coal pillars resulting in up to twice higher peak vertical stress and high strain energy accumulations in some western US mines in comparison with peak stresses predicted using common empirical pillar design methods. It is the unstable release of this strain energy that can cause significant damage resulting from pillar dilation and ground movements. These forces are much greater than the capacity of most common internal support systems, resulting in horizontal stressinduced roof falls locally, in mines under unremarkable far-field horizontal stress. Attention should be placed on pillar designs as increasing support density may prove to be ineffective. This mechanism is analyzed using field measurements and generic finite-difference stress analyses. The study confirms the higher load carrying capacity of confinement-controlled coal seams in comparison with structurally controlled coal seams. Such significant differences in confining stresses are not taken into account when estimating peak pillar strength using most common empirical techniques such as those proposed by Bieniawski and Salamon. While using lower pillar strength estimates may be considered conservative,it underestimates the actual capacity of pillars in accumulating much higher stress and strain energies,misleading the designer and inadvertently diminishing mine safety. The role of induced horizontal stress in mine pillars and surrounding strata is emphasized in coal pillar mechanics of violent failure. The triggering mechanism for the violent events is sudden loss of pillar confinement due to dynamic loading resulting from failure of overlying stiff and strong strata. Evidence of such mechanism is noted in the field by observed red-dust at the coal-rock interfaces at the location of coal bumps and irregular, periodic caving in room-and-pillar mines quantified through direct pressure measurements in the gob.展开更多
Willa Cather was the first woman frontier writer in American literary history who devoted herself to the portrayal of frontier life of pioneers in the Middle West America. She has successfully created a series of movi...Willa Cather was the first woman frontier writer in American literary history who devoted herself to the portrayal of frontier life of pioneers in the Middle West America. She has successfully created a series of moving women images. Most of Cather＇s female images are strong-minded and independent, attempting to take the fate into their own hands. In a sense, she can be regarded as a precursor of modern feminism. 0 Pioneers is the first mature book of Willa Cather, with the heroic protagonist, Alexandra, the representative of such women characters. With the application of the feminist literary approach, the thesis makes a detailed analysis of the heroine Alexandra in an attempt to illustrate and prove Cather＇s feminist thinking tendency. The present paper aims to analyze the feminist thoughts of Alexandra from the perspectives of her Revolt against ＂Woman Myth＂, her struggle against patriarchal society, and her longing for a real equality between men and women.展开更多
Tertiary sandstones collected from southwest Sarawak, Malaysia, were analyzed to decipher their provenance, weathering, and tectonic setting. The studied sandstones have a sublitharenite composition and are dominantly...Tertiary sandstones collected from southwest Sarawak, Malaysia, were analyzed to decipher their provenance, weathering, and tectonic setting. The studied sandstones have a sublitharenite composition and are dominantly composed quartz with little mica and feldspar, and a small amount of volcanic fragments. These sand- stones were generally derived from quartz-rich recycled orogenic sources. They have relatively high SiO2 content with low Na20, CaO, MnO, and MgO contents. Values of Chemical Index of Alteration （CIA） of these rock samples vary from 71 to 93, with an average of 81, implying intense chemical alteration during weathering. A felsic igneous source is suggested by a low concentration of TiO2 com- pared to CIA, enrichment of Light Rare Earth Elements, depletion of Heavy Rare Earth Elements, and negative Eu anomalies. A felsic origin is further supported by a Eu/Eu＊ range of 0.65-0.85 and high Th/Sc, La/Sc, La/Co, and Th/ Co ratios. This work presents the first reported geochemical data of Tertiary sandstones of the Sarawak Basin. These data led us to conclude that the sandstones were dislodged from recycled orogenic sources and deposited in a slowly subsiding rifted basin in a passive continental tectonic setting.展开更多
The planet responds thermally to the impacts of nova WZ Sagittae debris by heating and cooling. The result in the first 19 years of the nova WZ Sagittae cycle is global warming that is hemi-spherically dependent and i...The planet responds thermally to the impacts of nova WZ Sagittae debris by heating and cooling. The result in the first 19 years of the nova WZ Sagittae cycle is global warming that is hemi-spherically dependent and is detectable in South America ice core data and Antarctica surface mass balance data. Planetary thermal data are correlated in the past by calculating the debris impact times from the super outbursts times of nova WZ Sagittae. The shape of the arctic ice cap is dependent on the 220 degree path of the debris and does not exist southward between the western extension and eastern termini of nova WZ Sagittae that define the Arctic heating path. Future global heating from nova WZ Sagittae will begin in 2020-2021. The increase of 6 to 8 magnitude unusual earthquakes in recent years is the results of nova WZ Sagittae and SN 1054 debris impact. Unusual occurrences in the biosphere indicate the starting time of impacting supernova debris streams. The Antarctic sea ice distribution in November of 2016 defines the termini of maximum particle concentration impact from supernova 1006 in the southern hemisphere. The killing heat in India of the northern hemisphere is associated with the western terminus of this supernova. Novas and supernovas times of impact correlate with plague outbreaks in the western USA marking the particles in the debris streams as the cause of the disease.展开更多
基金the RIT College of Liberal Arts Faculty Research Fund for supplemental funding that enabled presentation of the preliminary results at the above mentioned AERE Conference in Asheville, NC
文摘The purpose of this paper is to explore the promise of utilizing some relatively new feedback control techniques in ecosystem management. First, we set forth a basic ecological-economic model of a predator-prey-hunting system in which both the predator and prey have use(flow) and non-use(stock) value and when the predator can inflict transboundary damages. We then use new data from the US Mountain West to show how a particular feedback approach—linear parameter-varying(LPV) control—can be utilized in this context. Our LPV model is able to quantify the cost of managing disturbances that inevitably arise as a manager tries to keep the actual path of the system "close" to its optimum. The results suggest management strategies in mountain ecosystems that feature large, mammalian carnivores.
文摘Methods of improving seismic event locations were investigated as part of a research study aimed at reducing ground control safety hazards. Seismic event waveforms collected with a 23-station three-dimensional sensor array during longwall coal mining provide the data set used in the analyses. A spatially variable seismic velocity model is constructed using seismic event sources in a passive tomographic method. The resulting three-dimensional velocity model is used to relocate seismic event positions. An evolutionary optimization algorithm is implemented and used in both the velocity model development and in seeking improved event location solutions. Results obtained using the different velocity models are compared. The combination of the tomographic velocity model development and evolutionary search algorithm provides improvement to the event locations.
文摘This paper seeks to enhance the understanding that the horizontal stresses build up and release during coal pillar loading and unloading(post-failure) drawing upon three decades of observations, geomechanical monitoring and numerical modeling in bump-prone U.S. mines. The focus is on induced horizontal stress in mine pillars and surrounding strata as highly stressed pillars punch into the roof and floor, causing shear failure and buckling of strata; under stiff stratigraphic units of some western US mines, these events could be accompanied by violent failure of pillar cores. Pillar punching eventually results in tensile stresses at the base of the pillar, facilitating transition into the post-failure regime; this transition will be nonviolent if certain conditions are met, notably the presence of interbedded mudstones with low shear strength properties and proper mine designs for controlling seismicity and dynamic loads. The study clearly shows high confining stress build-up in coal pillars resulting in up to twice higher peak vertical stress and high strain energy accumulations in some western US mines in comparison with peak stresses predicted using common empirical pillar design methods. It is the unstable release of this strain energy that can cause significant damage resulting from pillar dilation and ground movements. These forces are much greater than the capacity of most common internal support systems, resulting in horizontal stressinduced roof falls locally, in mines under unremarkable far-field horizontal stress. Attention should be placed on pillar designs as increasing support density may prove to be ineffective. This mechanism is analyzed using field measurements and generic finite-difference stress analyses. The study confirms the higher load carrying capacity of confinement-controlled coal seams in comparison with structurally controlled coal seams. Such significant differences in confining stresses are not taken into account when estimating peak pillar strength using most common empirical techniques such as those proposed by Bieniawski and Salamon. While using lower pillar strength estimates may be considered conservative,it underestimates the actual capacity of pillars in accumulating much higher stress and strain energies,misleading the designer and inadvertently diminishing mine safety. The role of induced horizontal stress in mine pillars and surrounding strata is emphasized in coal pillar mechanics of violent failure. The triggering mechanism for the violent events is sudden loss of pillar confinement due to dynamic loading resulting from failure of overlying stiff and strong strata. Evidence of such mechanism is noted in the field by observed red-dust at the coal-rock interfaces at the location of coal bumps and irregular, periodic caving in room-and-pillar mines quantified through direct pressure measurements in the gob.
文摘Willa Cather was the first woman frontier writer in American literary history who devoted herself to the portrayal of frontier life of pioneers in the Middle West America. She has successfully created a series of moving women images. Most of Cather＇s female images are strong-minded and independent, attempting to take the fate into their own hands. In a sense, she can be regarded as a precursor of modern feminism. 0 Pioneers is the first mature book of Willa Cather, with the heroic protagonist, Alexandra, the representative of such women characters. With the application of the feminist literary approach, the thesis makes a detailed analysis of the heroine Alexandra in an attempt to illustrate and prove Cather＇s feminist thinking tendency. The present paper aims to analyze the feminist thoughts of Alexandra from the perspectives of her Revolt against ＂Woman Myth＂, her struggle against patriarchal society, and her longing for a real equality between men and women.
基金the project (PPP) PG003-2013A of the University of Malaya, Kuala Lumpur, Malaysia in carrying out this research work is gratefully acknowledgedthe project RP002C-13AFR of the University of Malaya is also gratefully acknowledged
文摘Tertiary sandstones collected from southwest Sarawak, Malaysia, were analyzed to decipher their provenance, weathering, and tectonic setting. The studied sandstones have a sublitharenite composition and are dominantly composed quartz with little mica and feldspar, and a small amount of volcanic fragments. These sand- stones were generally derived from quartz-rich recycled orogenic sources. They have relatively high SiO2 content with low Na20, CaO, MnO, and MgO contents. Values of Chemical Index of Alteration （CIA） of these rock samples vary from 71 to 93, with an average of 81, implying intense chemical alteration during weathering. A felsic igneous source is suggested by a low concentration of TiO2 com- pared to CIA, enrichment of Light Rare Earth Elements, depletion of Heavy Rare Earth Elements, and negative Eu anomalies. A felsic origin is further supported by a Eu/Eu＊ range of 0.65-0.85 and high Th/Sc, La/Sc, La/Co, and Th/ Co ratios. This work presents the first reported geochemical data of Tertiary sandstones of the Sarawak Basin. These data led us to conclude that the sandstones were dislodged from recycled orogenic sources and deposited in a slowly subsiding rifted basin in a passive continental tectonic setting.
文摘The planet responds thermally to the impacts of nova WZ Sagittae debris by heating and cooling. The result in the first 19 years of the nova WZ Sagittae cycle is global warming that is hemi-spherically dependent and is detectable in South America ice core data and Antarctica surface mass balance data. Planetary thermal data are correlated in the past by calculating the debris impact times from the super outbursts times of nova WZ Sagittae. The shape of the arctic ice cap is dependent on the 220 degree path of the debris and does not exist southward between the western extension and eastern termini of nova WZ Sagittae that define the Arctic heating path. Future global heating from nova WZ Sagittae will begin in 2020-2021. The increase of 6 to 8 magnitude unusual earthquakes in recent years is the results of nova WZ Sagittae and SN 1054 debris impact. Unusual occurrences in the biosphere indicate the starting time of impacting supernova debris streams. The Antarctic sea ice distribution in November of 2016 defines the termini of maximum particle concentration impact from supernova 1006 in the southern hemisphere. The killing heat in India of the northern hemisphere is associated with the western terminus of this supernova. Novas and supernovas times of impact correlate with plague outbreaks in the western USA marking the particles in the debris streams as the cause of the disease.
