1,354 research outputs found

    Design, Construction, and Monitoring of the Ground-Water Resources of a Large Mine-Spoil Area: Star Fire Tract, Eastern Kentucky

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    By the year 2010, the Star Fire mining operation in Knott, Breathitt, and Perry Counties in eastern Kentucky, which uses mountaintop-removal and hollow-fill mining techniques, will have created approximately 5,000 acres of gently rolling terrain that could support alternative land uses. The present research is centered on approximately 1,000 acres of spoil created since mining began in 1981. An aquifer fed by both ground and surface water will be created within the spoil. Spoil-handling techniques such as cast blasting, dragline placement, end dumping by trucks, and surface grading have created porous coarse-rock zones within the spoil through which ground water can move. A vertical rubble chimney in the spoil has been constructed of durable rock to enhance infiltration to the ground-water reservoir through a surface infiltration basin. Fourteen monitoring wells have been installed along with flumes to gage surface-water discharge and monitor water quantity and quality at the site. Dye-tracing studies have identified ground-water flow paths and flow velocities. A preliminary assessment of the water resources at the site indicates that a stable water table has been created at the mined site. Based on an average saturated thickness of 21 feet for the entire site and an estimated porosity of 20 percent, the spoil stores approximately 4,200 acre-feet (1.37 billion gallons) of water. Dye-tracing data, hydraulic gradients, and water-quality data indicate that ground water moves more slowly in the spoil\u27s interior; from there it flows down into the hollow fills before discharging as springs along the bottom of the spoil. The springs discharge approximately 1 million gallons per day under normal flow conditions, and discharges of approximately 5 million gallons per day have been measured a week after rainfall events

    Using Remote Sensing and Inclined Drilling to Locate High-Yield Water Wells in the Eastern Kentucky Coal Field

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    The Kentucky Geological Survey has developed a method using lineament analysis in conjunction with inclinced exploration boreholes to identify subsurface fractures in the Eastern Kentucky Coal Field. Wells are then drilled to intersect these fractures, with the hope that the wells will be high yielding (greater than 30 gal/min). Lineaments were selected from Landsat TM imagery, side-looking airborne radar (SLAR) imagery, and two enhanced Landsat TM images for over 6,400 square miles of eastern Kentucky. Lineaments were replotted on 7.5-minute topographic quadrangle maps, and field reconnaissance identified locations where lineaments correlated with straight-line topographic features and fracture zones. Subsquent application of an inclined drilling technique at six sites has resulted in four production wells with yields ranging from 47 to 72 gal/min. All production wells intersected fractured rock. According to data from the Kentucky Groundwater Data Repository through October 2002, the yields of these four production wells are greater than the yields of 95 percent of the wells drilled in the Eastern Kentucky Coal Field. This study suggests that to minimize the chances of encountering salty groundwater, the best sites for high-yield wells are in first- or second-order stream valleys with fracture zones

    Ground Water in the Kentucky River Basin

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    Most private wells in the Kentucky River Basin are in unconfined or semi-confined bedrock aquifers. Within these aquifers, high-yield zones are irregularly distributed. The most productive wells are drilled into fractured bedrock and alluvium along the Kentucky River floodplain. The data indicate that ground water acts as a buffer to peak and low flows in Kentucky River Basin streams. At current withdrawal rates, ground-water usage does not seem to have an adverse impact on the Kentucky River. Privately owned ground-water sources supply approximately 135,000 people living in the basin-approximately 19 percent of the total population and 36 percent of the rural population. More than 50 percent of residential water supplies in eastern Kentucky rely on ground water. If aquifers are protected from pollution by wellhead protection programs and old wells are retrofitted to prevent direct contamination, then ground water will continue to provide a reliable water supply in many rural areas of the basin. However, for most of the basin, few wells will have yields adequate to supply a large demand. Ground water from present wells will not provide an adequate supply for communities with a population of over a few thousand. Limited discharge data available for springs and large wells in the basin strongly suggest that the potential for ground water to supplement current supplies should not be ignored. Discharge from well fields and springs could be used to augment surface supplies during drought. A better understanding of the distribution and quality of ground-water resources is crucial for the citizens of the basin to fully benefit from ground water

    Hydrogeology, Hydrogeochemistry, and Spoil Settlement at a Large Mine-Spoil Area in Eastern Kentucky: Star Fire Tract

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    An applied research program at the Star Fire surface mine in eastern Kentucky, owned and operated by Cypress-AMAX Coal Co., defined spoil characteristics to develop and monitor water resources, which will help identify a reliable water supply for future property development. Water stored in the mine spoil may provide a usable ground-water supply, and the spoil could also be engineered to provide base flow to surfacewater reservoirs. Ground-water recharge enters the spoil by way of sinking streams, ground-water flow from bedrock in contact with the mine spoil, and a specially designed infiltration basin. Ground water discharges predominantly from springs and seeps along the northwestern outslope of the spoil. A conceptual model of ground-water flow, based on data from monitoring wells, discharge from springs and ponds, dye tracing, hydraulic gradients, and field reconnaissance, indicates that ground water moves slowly in the spoil interior, where it must flow down into the valley fills before discharging out of the spoil. Two saturated zones have been established: the first in the spoil interior, and the second in the valley fills that surround the main spoil body at lower elevations. The saturated zone in the valley fills contains fresher water than the zone in the spoil interior and exhibits more water-level fluctuation because of efficient recharge pathways along the spoil’s periphery at the spoil-highwall contact. The average saturated thickness of the valley fill areas (30.1 ft) is approximately twice the average saturated thickness found in the spoil’s interior (15.4 ft). Spatial water-quality variations are consistent with those predicted in the proposed flow system. Based on an estimated average saturated thickness of 21 ft for the entire site, the saturated spoil stores 4,200 acre-ft (1.4 billion gallons) of water. Hydraulic-conductivity (K) values derived from slug tests range from 2.0 × 10-6 to more than 2.9 × 10-5 ft/sec, and are consistent with hydraulic-conductivity data for other spoil areas where similar mining methods are used. Water samples taken from wells and springs indicate that the ground water is a calcium-magnesium-sulfate type, differing mainly in the total concentration of these constituents at various locations. Mineral saturation indices calculated using the geochemical model PHREEQE indicate that most of the ground water is near equilibrium with gypsum. Nearly all the water samples had pH measurements in a favorable range between 6.0 and 7.0, indicating that the spoil does not produce highly acidic water. Measurements of vertical displacement around the monitoring-well surface casings indicate that differential settlement is occurring within the mine spoil. The most rapid settlement occurs in the most recently placed spoil near the active mining pit

    Applications for detection of acute kidney injury using electronic medical records and clinical information systems: Workgroup statements from the 15<sup>th</sup> ADQI Consensus Conference

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    Electronic medical records and clinical information systems are increasingly used in hospitals and can be leveraged to improve recognition and care for acute kidney injury. This Acute Dialysis Quality Initiative (ADQI) workgroup was convened to develop consensus around principles for the design of automated AKI detection systems to produce real-time AKI alerts using electronic systems. AKI alerts were recognized by the workgroup as an opportunity to prompt earlier clinical evaluation, further testing and ultimately intervention, rather than as a diagnostic label. Workgroup members agreed with designing AKI alert systems to align with the existing KDIGO classification system, but recommended future work to further refine the appropriateness of AKI alerts and to link these alerts to actionable recommendations for AKI care. The consensus statements developed in this review can be used as a roadmap for development of future electronic applications for automated detection and reporting of AKI

    Combined searches for the production of supersymmetric top quark partners in proton–proton collisions at √s=13Te

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    A combination of searches for top squark pair production using proton–proton collision data at a center-of-mass energy of 13TeV at the CERN LHC, corresponding to an integrated luminosity of 137fb−1^{-1} collected by the CMS experiment, is presented. Signatures with at least 2 jets and large missing transverse momentum are categorized into events with 0, 1, or 2 leptons. New results for regions of parameter space where the kinematical properties of top squark pair production and top quark pair production are very similar are presented. Depending on the model, the combined result excludes a top squark mass up to 1325GeV for a massless neutralino, and a neutralino mass up to 700GeV for a top squark mass of 1150GeV. Top squarks with masses from 145 to 295GeV, for neutralino masses from 0 to 100GeV, with a mass difference between the top squark and the neutralino in a window of 30GeV around the mass of the top quark, are excluded for the first time with CMS data. The results of theses searches are also interpreted in an alternative signal model of dark matter production via a spin-0 mediator in association with a top quark pair. Upper limits are set on the cross section for mediator particle masses of up to 420GeV

    Search for a vector-like quark Tâ€Č → tH via the diphoton decay mode of the Higgs boson in proton-proton collisions at s \sqrt{s} = 13 TeV

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    A search for the electroweak production of a vector-like quark Tâ€Č, decaying to a top quark and a Higgs boson is presented. The search is based on a sample of proton-proton collision events recorded at the LHC at = 13 TeV, corresponding to an integrated luminosity of 138 fb−1. This is the first Tâ€Č search that exploits the Higgs boson decay to a pair of photons. For narrow isospin singlet Tâ€Č states with masses up to 1.1 TeV, the excellent diphoton invariant mass resolution of 1–2% results in an increased sensitivity compared to previous searches based on the same production mechanism. The electroweak production of a Tâ€Č quark with mass up to 960 GeV is excluded at 95% confidence level, assuming a coupling strength ÎșT = 0.25 and a relative decay width Γ/MTâ€Č < 5%

    Measurement of the top quark mass using events with a single reconstructed top quark in pp collisions at s\sqrt{s} = 13 TeV

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    A measurement of the top quark mass is performed using a data sample enriched with single top quark events produced in the t channel. The study is based on proton- proton collision data, corresponding to an integrated luminosity of 35.9 fb−1^{-1}, recorded at s\sqrt{s} = 13 TeV by the CMS experiment at the LHC in 2016. Candidate events are selected by requiring an isolated high-momentum lepton (muon or electron) and exactly two jets, of which one is identified as originating from a bottom quark. Multivariate discriminants are designed to separate the signal from the background. Optimized thresholds are placed on the discriminant outputs to obtain an event sample with high signal purity. The top quark mass is found to be 172.13+0.76^{+0.76}−0.77_{-0.77} GeV, where the uncertainty includes both the statistical and systematic components, reaching sub-GeV precision for the first time in this event topology. The masses of the top quark and antiquark are also determined separately using the lepton charge in the final state, from which the mass ratio and difference are determined to be 0.9952+0.0079^{+0.0079}−0.0104_{-0.0104} and 0.83+1.79^{+1.79}−1.35_{-1.35} GeV, respectively. The results are consistent with CPT invariance

    Search for a right-handed W boson and a heavy neutrino in proton-proton collisions at s \sqrt{s} = 13 TeV

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    A search is presented for a right-handed W boson (WR) and a heavy neutrino (N), in a final state consisting of two same-flavor leptons (ee or ΌΌ) and two quarks. The search is performed with the CMS experiment at the CERN LHC using a data sample of proton-proton collisions at a center-of-mass energy of 13 TeV corresponding to an integrated luminosity of 138 fb−1. The search covers two regions of phase space, one where the decay products of the heavy neutrino are merged into a single large-area jet, and one where the decay products are well separated. The expected signal is characterized by an excess in the invariant mass distribution of the final-state objects. No significant excess over the standard model background expectations is observed. The observations are interpreted as upper limits on the product of WR production cross sections and branching fractions assuming that couplings are identical to those of the standard model W boson. For N masses mN equal to half the WR mass mWR (mN = 0.2 TeV), mWR is excluded at 95% confidence level up to 4.7 (4.8) and 5.0 (5.4) TeV for the electron and muon channels, respectively. This analysis provides the most stringent limits on the WR mass to date

    Precision luminosity measurement in proton–proton collisions at √s=13TeV in 2015 and 2016 at CMS

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    The measurement of the luminosity recorded by the CMS detector installed at LHC interaction point 5, using proton–proton collisions at √s=13TeV in 2015 and 2016, is reported. The absolute luminosity scale is measured for individual bunch crossings using beam-separation scans (the van der Meer method), with a relative precision of 1.3 and 1.0% in 2015 and 2016, respectively. The dominant sources of uncertainty are related to residual differences between the measured beam positions and the ones provided by the operational settings of the LHC magnets, the factorizability of the proton bunch spatial density functions in the coordinates transverse to the beam direction, and the modeling of the effect of electromagnetic interactions among protons in the colliding bunches. When applying the van der Meer calibration to the entire run periods, the integrated luminosities when CMS was fully operational are 2.27 and 36.3 fb−1^{-1} in 2015 and 2016, with a relative precision of 1.6 and 1.2%, respectively. These are among the most precise luminosity measurements at bunched-beam hadron colliders
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