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https://www.readbyqxmd.com/read/28926929/response-characteristics-and-experimental-study-of-underground-magnetic-resonance-sounding-using-a-small-coil-sensor
#1
Shengwu Qin, Zhongjun Ma, Chuandong Jiang, Jun Lin, Yiguo Xue, Xinlei Shang, Zhiqiang Li
Due to its unique sensitivity to hydrogen protons, magnetic resonance sounding (MRS) is the only geophysical method that directly detects water and can provide nondestructive information on subsurface aquifer properties. The relationship between the surface MRS signal and the location and characteristics of aquifers using large-coil (typically 50-150 m) sensors has been discussed based on forward modelling and experiments. However, few researchers have studied underground MRS using a small-coil sensor. In this paper, a parametric study and a large-scale physical model test were conducted to shed light on the critical response characteristics of underground MRS using a small-coil sensor...
September 15, 2017: Sensors
https://www.readbyqxmd.com/read/28924728/a-review-on-the-mechanism-risk-evaluation-and-prevention-of-coal-spontaneous-combustion-in-china
#2
Biao Kong, Zenghua Li, Yongliang Yang, Zhen Liu, Daocheng Yan
In recent years, the ecology, security, and sustainable development of modern mines have become the theme of coal mine development worldwide. However, spontaneous combustion of coal under conditions of oxygen supply and automatic exothermic heating during coal mining lead to coalfield fires. Coal spontaneous combustion (CSC) causes huge economic losses and casualties, with the toxic and harmful gases produced during coal combustion not only polluting the working environment, but also causing great damage to the ecological environment...
September 18, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28924611/size-effects-resolve-discrepancies-in-40-years-of-work-on-low-temperature-plasticity-in-olivine
#3
Kathryn M Kumamoto, Christopher A Thom, David Wallis, Lars N Hansen, David E J Armstrong, Jessica M Warren, David L Goldsby, Angus J Wilkinson
The strength of olivine at low temperatures and high stresses in Earth's lithospheric mantle exerts a critical control on many geodynamic processes, including lithospheric flexure and the formation of plate boundaries. Unfortunately, laboratory-derived values of the strength of olivine at lithospheric conditions are highly variable and significantly disagree with those inferred from geophysical observations. We demonstrate via nanoindentation that the strength of olivine depends on the length scale of deformation, with experiments on smaller volumes of material exhibiting larger yield stresses...
September 2017: Science Advances
https://www.readbyqxmd.com/read/28923777/an-improved-method-for-permeability-estimation-of-the-bioclastic-limestone-reservoir-based-on-nmr-data
#4
Xinmin Ge, Yiren Fan, Jianyu Liu, Li Zhang, Yujiao Han, Donghui Xing
Permeability is an important parameter in formation evaluation since it controls the fluid transportation of porous rocks. However, it is challengeable to compute the permeability of bioclastic limestone reservoirs by conventional methods linking petrophysical and geophysical data, due to the complex pore distributions. A new method is presented to estimate the permeability based on laboratory and downhole nuclear magnetic resonance (NMR) measurements. We divide the pore space into four intervals by the inflection points between the pore radius and the transversal relaxation time...
September 9, 2017: Journal of Magnetic Resonance
https://www.readbyqxmd.com/read/28922351/estimation-of-the-mechanical-properties-of-the-eye-through-the-study-of-its-vibrational-modes
#5
M Á Aloy, J E Adsuara, P Cerdá-Durán, M Obergaulinger, J J Esteve-Taboada, T Ferrer-Blasco, R Montés-Micó
Measuring the eye's mechanical properties in vivo and with minimally invasive techniques can be the key for individualized solutions to a number of eye pathologies. The development of such techniques largely relies on a computational modelling of the eyeball and, it optimally requires the synergic interplay between experimentation and numerical simulation. In Astrophysics and Geophysics the remote measurement of structural properties of the systems of their realm is performed on the basis of (helio-)seismic techniques...
2017: PloS One
https://www.readbyqxmd.com/read/28919936/polar-applications-of-spaceborne-scatterometers
#6
David G Long
Wind scatterometers were originally developed for observation of near-surface winds over the ocean. They retrieve wind indirectly by measuring the normalized radar cross section (σ(o) ) of the surface, and estimating the wind via a geophysical model function relating σ(o) to the vector wind. The σ(o) measurements have proven to be remarkably capable in studies of the polar regions where they can map snow cover; detect the freeze/thaw state of forest, tundra, and ice; map and classify sea ice; and track icebergs...
May 2017: IEEE J Sel Top Appl Earth Obs Remote Sens
https://www.readbyqxmd.com/read/28904782/molecular-phylogeny-and-phylogeography-of-genus-pseudois-bovidae-cetartiodactyla-new-insights-into-the-contrasting-phylogeographic-structure
#7
Shuai Tan, Zhihong Wang, Lichun Jiang, Rui Peng, Tao Zhang, Quekun Peng, Fangdong Zou
Blue sheep, Pseudois nayaur, is endemic to the Tibetan Plateau and the surrounding mountains, which are the highest-elevation areas in the world. Classical morphological taxonomy suggests that there are two subspecies in genus Pseudois (Bovidae, Artiodactyla), namely Pseudois nayaur nayaur and Pseudois nayaur szechuanensis. However, the validity and geographic characteristics of these subspecies have never been carefully discussed and analyzed. This may be partially because previous studies have mainly focused on the vague taxonomic status of Pseudois schaeferi (dwarf blue sheep)...
September 2017: Ecology and Evolution
https://www.readbyqxmd.com/read/28895947/database-of-multi-parametric-geophysical-data-from-the-tomo-dec-experiment-on-deception-island-antarctica
#8
Jesús M Ibáñez, Alejandro Díaz-Moreno, Janire Prudencio, Daria Zandomeneghi, William Wilcock, Andrew Barclay, Javier Almendros, Carmen Benítez, Araceli García-Yeguas, Gerardo Alguacil
Deception Island volcano (Antarctica) is one of the most closely monitored and studied volcanoes on the region. In January 2005, a multi-parametric international experiment was conducted that encompassed both Deception Island and its surrounding waters. We performed this experiment from aboard the Spanish oceanographic vessel 'Hespérides', and from five land-based locations on Deception Island (the Spanish scientific Antarctic base 'Gabriel de Castilla' and four temporary camps). This experiment allowed us to record active seismic signals using a large network of seismic stations that were deployed both on land and on the seafloor...
September 12, 2017: Scientific Data
https://www.readbyqxmd.com/read/28888234/disseminating-near-real-time-hazards-information-and-flood-maps-in-the-philippines-through-web-gis
#9
Alfredo Mahar Francisco A Lagmay, Bernard Alan Racoma, Ken Adrian Aracan, Jenalyn Alconis-Ayco, Ivan Lester Saddi
The Philippines being a locus of tropical cyclones, tsunamis, earthquakes and volcanic eruptions, is a hotbed of disasters. These natural hazards inflict loss of lives and costly damage to property. Situated in a region where climate and geophysical tempest is common, the Philippines will inevitably suffer from calamities similar to those experienced recently. With continued development and population growth in hazard prone areas, it is expected that damage to infrastructure and human losses would persist and even rise unless appropriate measures are immediately implemented by government...
September 2017: Journal of Environmental Sciences (China)
https://www.readbyqxmd.com/read/28878304/maximum-extent-and-decay-of-the-laurentide-ice-sheet-in-western-baffin-bay-during-the-last-glacial-episode
#10
Etienne Brouard, Patrick Lajeunesse
Reconstructing the extent, flow and decay of the Laurentide Ice Sheet (LIS) on the continental shelves of North America during the last glaciation provides paleoglaciological analogues that are essential for understanding and predicting how modern marine-based ice-sheets will respond to future climate change and sea level fluctuations. The geometry of the LIS during Marine isotope stage 2 (MIS-2; 29-14 ka BP) is one key element for ice-sheet modelling. The maximum extent of the LIS during this stage is well constrained for most sectors of the ice sheet, but major uncertainties remain, especially along the continental shelves of Arctic Canada...
September 6, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28873257/deep-uncertainties-in-sea-level-rise-and-storm-surge-projections-implications-for-coastal-flood-risk-management
#11
Perry C Oddo, Ben S Lee, Gregory G Garner, Vivek Srikrishnan, Patrick M Reed, Chris E Forest, Klaus Keller
Sea levels are rising in many areas around the world, posing risks to coastal communities and infrastructures. Strategies for managing these flood risks present decision challenges that require a combination of geophysical, economic, and infrastructure models. Previous studies have broken important new ground on the considerable tensions between the costs of upgrading infrastructure and the damages that could result from extreme flood events. However, many risk-based adaptation strategies remain silent on certain potentially important uncertainties, as well as the tradeoffs between competing objectives...
September 5, 2017: Risk Analysis: An Official Publication of the Society for Risk Analysis
https://www.readbyqxmd.com/read/28865808/monitoring-the-evolution-and-migration-of-a-methane-gas-plume-in-an-unconfined-sandy-aquifer-using-time-lapse-gpr-and-ert
#12
Colby M Steelman, Dylan R Klazinga, Aaron G Cahill, Anthony L Endres, Beth L Parker
Fugitive methane (CH4) leakage associated with conventional and unconventional petroleum development (e.g., shale gas) may pose significant risks to shallow groundwater. While the potential threat of stray (CH4) gas in aquifers has been acknowledged, few studies have examined the nature of its migration and fate in a shallow groundwater flow system. This study examines the geophysical responses observed from surface during a 72day field-scale simulated CH4 leak in an unconfined sandy aquifer at Canadian Forces Base Borden, Canada, to better understand the transient behaviour of fugitive CH4 gas in the subsurface...
August 30, 2017: Journal of Contaminant Hydrology
https://www.readbyqxmd.com/read/28863476/multi-dark-dark-solitons-of-the-integrable-repulsive-ab-system-via-the-determinants
#13
Guoqiang Zhang, Zhenya Yan, Xiao-Yong Wen
We investigate the integrable repulsive AB system and construct its Darboux transformation using the loop group method. The associated N-fold Darboux transformation is found in terms of simple determinants. Moreover, we derive multi-dark-dark solitons of the repulsive AB system with a non-vanishing background through the Darboux transformation with a limit procedure. Particularly, we exhibit the one-, two-, and three-dark-dark solitons. The results will be meaningful for the study of vector multi-dark solitons in many physical systems such as geophysical fluid dynamics and nonlinear optics...
August 2017: Chaos
https://www.readbyqxmd.com/read/28858678/integrated-hierarchical-geo-environmental-survey-strategy-applied-to-the-detection-and-investigation-of-an-illegal-landfill-a-case-study-in-the-campania-region-southern-italy
#14
Vincenzo Di Fiore, Giuseppe Cavuoto, Michele Punzo, Daniela Tarallo, Marco Casazza, Silvio Marco Guarriello, Massimiliano Lega
This paper describes an approach to detect and investigate the main characteristics of a solid waste landfill through the integration of geological, geographical and geophysical methods. In particular, a multi-temporal analysis of the landfill morphological evolution was carried out using aerial and satellite photos, since there were no geological and geophysical data referring to the study area. Subsequently, a surface geophysical prospection was performed through geoelectric and geomagnetic methods. In particular, the combination of electrical resistivity, induced polarization and magnetic measurements removed some of the uncertainties, generally associated with a separate utilization of these techniques...
August 24, 2017: Forensic Science International
https://www.readbyqxmd.com/read/28858209/understanding-animal-detection-of-precursor-earthquake-sounds
#15
Michael Garstang, Michael C Kelley
We use recent research to provide an explanation of how animals might detect earthquakes before they occur. While the intrinsic value of such warnings is immense, we show that the complexity of the process may result in inconsistent responses of animals to the possible precursor signal. Using the results of our research, we describe a logical but complex sequence of geophysical events triggered by precursor earthquake crustal movements that ultimately result in a sound signal detectable by animals. The sound heard by animals occurs only when metal or other surfaces (glass) respond to vibrations produced by electric currents induced by distortions of the earth's electric fields caused by the crustal movements...
August 31, 2017: Animals: An Open Access Journal From MDPI
https://www.readbyqxmd.com/read/28853137/water-table-uncertainties-due-to-uncertainties-in-structure-and-properties-of-an-unconfined-aquifer
#16
Juerg Hauser, Florian Wellmann, Mike Trefry
We consider two sources of geology-related uncertainty in making predictions of the steady-state water table elevation for an unconfined aquifer. That is the uncertainty in the depth to base of the aquifer and in the hydraulic conductivity distribution within the aquifer. Stochastic approaches to hydrological modeling commonly use geostatistical techniques to account for hydraulic conductivity uncertainty within the aquifer. In the absence of well data allowing derivation of a relationship between geophysical and hydrological parameters, the use of geophysical data is often limited to constraining the structural boundaries...
August 29, 2017: Ground Water
https://www.readbyqxmd.com/read/28834575/unexpected-stasis-in-a-changing-world-lake-nutrient-and-chlorophyll-trends-since-1990
#17
Samantha K Oliver, Sarah M Collins, Patricia A Soranno, Tyler Wagner, Emily H Stanley, John R Jones, Craig A Stow, Noah R Lottig
The United States (U.S.) has faced major environmental changes in recent decades, including agricultural intensification and urban expansion, as well as changes in atmospheric deposition and climate-all of which may influence eutrophication of freshwaters. However, it is unclear whether or how water quality in lakes across diverse ecological settings has responded to environmental change. We quantified water quality trends in 2913 lakes using nutrient and chlorophyll (Chl) observations from the Lake Multi-Scaled Geospatial and Temporal Database of the Northeast U...
August 23, 2017: Global Change Biology
https://www.readbyqxmd.com/read/28818968/the-turbulent-cascade-in-five-dimensions
#18
José I Cardesa, Alberto Vela-Martín, Javier Jiménez
To the naked eye, turbulent flows exhibit whirls of many different sizes. To each size, or scale, corresponds a fraction of the total energy resulting from a cascade in five dimensions: scale, time, and three-dimensional space. Understanding this process is critical to strategies for modeling geophysical and industrial flows. By tracking the flow regions containing energy in different scales, we have detected the statistical predominance of a cross-scale link whereby fluid lumps of energy at scale Δ appear within lumps of scale 2Δ and die within those of scale Δ/2...
August 25, 2017: Science
https://www.readbyqxmd.com/read/28805051/proposed-empirical-entropy-and-gibbs-energy-based-on-observations-of-scale-invariance-in-open-nonequilibrium-systems
#19
Adrian F Tuck
There is no widely agreed definition of entropy, and consequently Gibbs energy, in open systems far from equilibrium. One recent approach has sought to formulate an entropy and Gibbs energy based on observed scale invariances in geophysical variables, particularly in atmospheric quantities, including the molecules constituting stratospheric chemistry. The Hamiltonian flux dynamics of energy in macroscopic open nonequilibrium systems maps to energy in equilibrium statistical thermodynamics, and corresponding equivalences of scale invariant variables with other relevant statistical mechanical variables such as entropy, Gibbs energy, and 1/(kBoltzmannT), are not just formally analogous but are also mappings...
August 24, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28798127/a-unified-continental-thickness-from-seismology-and-diamonds-suggests-a-melt-defined-plate
#20
Saikiran Tharimena, Catherine Rychert, Nicholas Harmon
Thick, rigid continents move over the weaker underlying mantle, although geophysical and geochemical constraints on the exact thickness and defining mechanism of the continental plates are widely discrepant. Xenoliths suggest a chemical continental lithosphere ~175 kilometers thick, whereas seismic tomography supports a much thicker root (>250 kilometers) and a gradual lithosphere-asthenosphere transition, consistent with a thermal definition. We modeled SS precursor waveforms from continental interiors and found a 7 to 9% velocity drop at depths of 130 to 190 kilometers...
August 11, 2017: Science
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