Ash River Research Articles

Effect and mechanism of activators on the properties of Yellow River sediment/fly ash/cement-based alkali-activated cementitious materials used for coal mine filling

Preparing Yellow River sediment/fly ash/cement-based alkali-activated cementitious materials for coal mine filling can realize the large-scale consumption of Yellow River sediment and reduce the cost of coal mine filling materials. This paper studied the effects of Ca(OH)2, NaOH, and water glass on the properties of coal mine filling materials. Adding activators Ca(OH)2, NaOH, and water glass can improve the compressive strength and shorten the setting time of the filling materials. NaOH and water glass can also significantly reduce the bleeding rate. The mechanism of activators' influence on the mechanical properties of filling materials was explored based on XRD, TGA, FTIR, MIP, and SEM. The alkaline environment provided by NaOH and Ca(OH)2 accelerated the hydration reaction of cement, and the SiO32- from the hydrolysis of water glass can bind to Ca2+ to form C-S-H gel. The co-mixing of water glass and NaOH can make fly ash and Yellow River sediment's active components react more fully, generating more C-S-H and C-A-S-H gels. This can refine the pore size distribution of the filling materials, reduce the content of harmful pores, make the matrix dense, and improve the filling materials' working and mechanical properties. When the NaOH is 0.5 wt%, and the water glass is 13 wt%, the strength of the filling materials prepared by compound doping was the highest, and the working performance met the requirements. The results had broad application prospects and economic value, contributing to ecological and environmental protection and sustainable development.

Ultra-distal tephra deposits and Bayesian modelling constrain a variable marine radiocarbon offset in Placentia Bay, Newfoundland

Abstract. Radiocarbon dating marine sediments is complicated by the strongly heterogeneous age of ocean waters. Tephrochronology provides a well-established method to constrain the age of local radiocarbon reservoirs and more accurately calibrate dates. Numerous ultra-distal cryptotephra deposits (non-visible volcanic ash more than 3000 km from source) have been identified in peatlands and lake sediments across north-eastern North America and correlated with volcanic arcs in the Pacific north-west. Previously, however, these isochrons have not been identified in sediments from the north-west Atlantic Ocean. In this study, we report the presence of two ultra-distal cryptotephra deposits; Mazama Ash and White River Ash eastern lobe (WRAe), in Placentia Bay, North Atlantic Ocean. We use these well-dated isochrons to constrain the local marine radiocarbon reservoir offset (ΔR) and develop a robust Bayesian age–depth model with a ΔR that varies through time. Our results indicate that the marine radiocarbon offset in Placentia Bay was -126±151 years (relative to the Marine20 calibration curve) at the time of Mazama Ash deposition (7572 ± 18 yr BP) and −396 ± 144 years at the time of WRAe deposition (1098–1097 yr BP). Changes in ΔR appear to coincide with inferred shifts in relative influences of the inner Labrador Current and the Slopewater Current in the bay. An important conclusion is that single-offset models of ΔR are easiest to apply and often hard to disprove. However, such models may oversimplify reservoir effects in a core, even over relatively short timescales. Acknowledging potentially varying offsets is critical when ocean circulation and ventilation characteristics have differed over time. The addition of tephra isochrons permits the calculation of semi-independent reservoir corrections and verification of the single ΔR model.

ENSO Signals Recorded by Ash Tree Rings in Iberian Riparian Forests

Climate–atmospheric patterns affect ecological processes. The El Niño Southern Oscillation (ENSO) represents the strongest global source of climate variability at annual scales, but its impacts on Mediterranean forests are still understudied. Here, ENSO signals recorded by river flow and radial growth series of Mediterranean riparian forests are uncovered in the middle Ebro basin, northeastern Spain. A chronology or mean series of tree ring widths (period 1970–2018, 27 trees) was built for narrow-leaved ash (Fraxinus angustifolia). Growth indices increased as the river flow did during the prior winter and from May to September. Ash growth indices and river flow of the hydrological year were positively related (r = 0.54, p < 0.001), suggesting that a higher soil moisture enhances growth. This correlation remained significant after taking out the influence of precipitation. Ash growth indices (r = −0.46, p = 0.001) and river flow during the hydrological year (r = −0.30, p = 0.03) were negatively associated with the January Southern Oscillation Index (SOI). These relationships suggest that high SOI values corresponding to La Niña events lead to reduced river flow, thus decreasing ash radial growth. Further approaches could be used to better understand how the ENSO impacts drought-prone riparian forests subjected to increasing aridity.

Influence of fly ash, cement and ground river sand on compressive strength and chloride penetration of mortar

The study deals with the strength and chloride resistance properties of mortar prepared by combining the Portland cement 43 grade, fly-ash and ground river sand. Fly ash and ground river sand were utilized to partially replace ordinary Portland cement type I. The replacement percentage of fly ash and ground river sand was varied from 0 to 40% and the mortar mixes were prepared. Fly ash and ground river sand was processed using ball mill and sieve with openings of 45 µm (sieve No. 325) was used to obtain 3% weight retained. The mortar samples were tested for their strength (compressive), penetration (Rapid chloride) and microstructural properties. The results indicated that the strength (compressive) increased and resistance to chloride penetration was excellent. According to SEM analysis, homogeneous and dense structure of the newly developed mortar was observed. Ground river sand addition, however, reduced strength and improved chloride resistance which indicated that it made changes to only packing structure. Strength and penetration resistance were enhanced and it was due to the pozzolanic effect of fine fly ash.

Results from the NOvA Experiment

The NOvA experiment is a long-baseline accelerator-based neutrino oscillation experiment. It uses the upgraded NuMI beam from Fermilab to measure electron-neutrino appearance and muon-neutrino disappearance between the Near Detector, located at Fermilab, and the Far Detector, located at Ash River, Minnesota. The NuMI beam has recently reached and surpassed the 700 kW power benchmark. NOvA’s primary physics goals include precision measurements of oscillation parameters, such as [Formula: see text] and the atmospheric mass-squared splitting, along with probes of the mass hierarchy and of the CP violating phase. This talk will present the latest NOvA results, based on a neutrino beam exposure equivalent to [Formula: see text] protons-on-target.

Kill rates and predation rates of wolves on beavers

ABSTRACTWolves (Canis lupus) can be primary predators of beavers (Castor canadensis), but little is known about wolf‐beaver dynamics. We identified kills from 1 wolf (V009) of the Ash River Pack in Voyageurs National Park from 1 April to 5 November 2015 to provide direct estimates of wolf pack kill and predation rates of beavers. We documented 12 beaver kills by V009 during the 2015 ice‐free season and estimated V009 killed 22 beavers during this period. Based on the number of beavers killed by V009, we estimated the Ash River Pack removed 80–88 beavers (kill rate of 0.085–0.095 beavers/wolf/day), which was 38–42% of the beaver population in their home range during the ice‐free season. Even with this substantial level of predation in 2015, the beaver population in the Ash River Pack home range increased by an estimated 43% in 2016, which suggested dispersal from more densely populated adjacent areas likely compensated for the effects of wolf predation. We have presented the first direct estimate of wolf kill and predation rates on beavers, but more research is necessary to understand how wolf predation affects beaver populations under a variety of conditions. Published 2017. This article is a U.S. Government work and is in the public domain in the USA.

A search for sterile neutrinos at the NOvA Far Detector

NOvA is the current United States flagship long-baseline neutrino experiment designed to study the properties of neutrino oscillations. It consists of two functionally identical detectors each located 14.6 mrad off the central axis from the Fermilab NuMI neutrino beam. The Near Detector is located 1 km downstream from the beam source, and the Far Detector is located 810 km away in Ash River, Minnesota. This long baseline, combined with the ability of the NuMI facility to switch between nearly pure neutrino and anti-neutrino beams, allows NOvA to make precision measurements of neutrino mixing angles, potentially determine the neutrino mass hierarchy, and begin searching for CP violating effects in the lepton sector. However, NOvA can also probe more exotic scenarios, such as oscillations between the known active neutrinos and new sterile species. We will showcase the first search for sterile neutrinos in a 3 + 1 model at NOvA. The analysis presented searches for a deficit in the rate of neutral current events at the Far Detector using the Near Detector to constrain the predicted spectrum. This analysis was performed using data taken between February 2014 and May 2016 corresponding to 6.05 × 1020 protons on target.

Integration of the Super Nova Early Warning System with the NOvA Trigger

The NOvA experiment, with a baseline of 810km, samples Fermilab's upgraded NuMI beam with a Near Detector on-site and a Far Detector (FD) at Ash River, MN, to observe oscillations of muon neutrinos. The 344,064 liquid scintillator-filled cells of the 14kton FD provide high granularity of a large detector mass and enable us to also study non-accelerator based neutrinos with our Data Driven Trigger framework. This paper will focus on the real time integration of the SNEWS with the NOvA Trigger where we have set up an XML-RPC based messaging system to inject the SNEWS signal directly into our trigger. This presents a departure from the E-Mail based notification mechanism used by SNEWS in the past and allows NOvA more control over propagation and transmission timing.

The NOvA simulation chain

The NOνA experiment is a two-detector, long-baseline neutrino experiment operating in the recently upgraded NuMI muon neutrino beam. Simulating neutrino interactions and backgrounds requires many steps including: the simulation of the neutrino beam flux using FLUKA and the FLUGG interface; cosmic ray generation using CRY; neutrino interaction modeling using GENIE; and a simulation of the energy deposited in the detector using GEANT4. To shorten generation time, the modeling of detector-specific aspects, such as photon transport, detector and electronics noise, and readout electronics, employs custom, parameterized simulation applications. We will describe the NOνA simulation chain, and present details on the techniques used in modeling photon transport near the ends of cells, and in developing a novel data-driven noise simulation. Due to the high intensity of the NuMI beam, the Near Detector samples a high rate of muons originating in the surrounding rock. In addition, due to its location on the surface at Ash River, MN, the Far Detector collects a large rate (˜ 140 kHz) of cosmic muons. We will discuss the methods used in NOνA for overlaying rock muons and cosmic ray muons with simulated neutrino interactions and show how realistically the final simulation reproduces the preliminary NOνA data.

A data summary file structure and analysis tools for neutrino oscillation analysis at the NOvA experiment

The NuMI Off-axis Neutrino Experiment (NOvA) is designed to study neutrino oscillations in the NuMI beam at Fermilab. Neutrinos at the Main Injector (NuMI) is currently being upgraded to provide 700 kW for NOvA. A 14 kt Far Detector in Ash River, MN and a functionally identical 0.3 kt Near Detector at Fermilab are positioned 810 km apart in the NuMI beam line. The fine granularity of the NOvA detectors provides a detailed representation of particle trajectories. The data volume associated with such granularity, however, poses problems for analyzing data with ease and speed. NOvA has developed a data summary file structure which discards the full event record in favor of higher-level reconstructed information. A general- purpose framework for neutrino oscillation measurements has been developed for analysis of these data summary files. We present the design methodology for this new file format as well as the analysis framework and the role it plays in producing NOvA physics results.

The NOvA DAQ Monitor System

The NOvA (NuMI Off-Axis ve Appearance) experiment is a long-baseline neutrino experiment designed to search for vµ (v̅µ) to ve (v̅e) oscillations using Fermilab's NuMI main injector neutrino beam. The experiment consists of two detectors; both positioned 14 mrad off the beam axis: a 220 ton Near Detector constructed in an underground cavern at Fermilab and a 14 kton Far Detector constructed in Ash River, MN, 810 km from the beam source. The health and performance of the NOvA Data Acquisition (DAQ) system is monitored with a DAQ Monitor system based on the Ganglia distributed monitoring system, an open source third-party product which provides much of the NOvA DAQ monitoring needs “out-of-the-box”. This paper will discuss the use of the Ganglia system for this purpose, including augmentations we have made to the Ganglia base for the specific needs of our system. This paper will also discuss two other systems used to monitor the quality of the data collected by the NOvA detectors: an Online Monitoring system and Event Display, both of which leverage tools from the offline framework to provide close to real time diagnostic tools of detector performance.

Archiving Scientific Data Outside of the Traditional HEP Domain, Using the Archive Facilities at Fermilab

Many experiments in the HEP and Astrophysics communities generate large extremely valuable datasets, which need to be efficiently cataloged and recorded to archival storage. These datasets, both new and legacy, are often structured in a manner that is not conducive to storage and cataloging with modern data handling systems and large file archive facilities. In this paper we discuss in detail how we have created a robust toolset and simple portal into the Fermilab archive facilities, which allows for scientific data to be quickly imported, organized and retrieved from the multi-petabyte facility.In particular we discuss how the data from the Sudbury Neutrino Observatory (SNO) for the COUPP dark matter detector was aggregated, cataloged, archived and re-organized to permit it to be retrieved and analyzed using modern distributed computing resources both at Fermilab and on the Open Science Grid. We pay particular attention to the methods that were employed to uniquify the namespaces for the data, derive metadata for the over 460,000 image series taken by the COUP experiment and what was required to map that information into coherent datasets that could be stored and retrieved using the large scale archives systems.We describe the data transfer and cataloging engines that are used for data importation and how these engines have been setup to import data from the data acquisition systems of ongoing experiments at non-Fermilab remote sites including the Laboratori Nazionali del Gran Sasso and the Ash River Laboratory in Orr, Minnesota. We also describe how large University computing sites around the world are using the system to store and retrieve large volumes of simulation and experiment data for physics analysis.

Strength and chloride resistance of the blended Portland cement mortar containing rice husk ash and ground river sand

In this paper, the strength and chloride penetration resistance of the blended Portland cement mortar containing rice husk ash (RHA) and ground river sand (GS) were studied. Portland cement type I (OPC) was partially replaced with RHA and GS and a blended of RHA and GS. The mortar mixtures were made with OPC containing 0–40 % of RHA and GS. RHA and GS with 3 % by weight retained on sieve No. 325 (opening 45 µm of sieve No. 325) were obtained using ball mill. The study includes compressive strength, rapid chloride penetration test, chloride ion diffusion coefficient and chloride penetration depth of mortars. Test results indicated that the use of RHA produced mortars with relatively high strength and excellent resistance to chloride penetration. However, the incorporation of GS reduced the strength and resistance to chloride penetration of mortars indicating that it asserted only the packing effect. The blend of equal portions of RHA and GS produced relatively high strength mortars with good resistance to chloride penetration which is probably due to the synergy of the pozzolanic effect of RHA and packing effect of GS.

The NOνA Far Detector Data Acquisition System

The NOνA experiment is a long-baseline neutrino experiment designed to make measurements to determine the neutrino mass hierarchy, neutrino mixing parameters and CP violation in the neutrino sector. In order to make these measurements the NOνA collaboration has designed a highly distributed, synchronized, continuous digitization and readout system that is able to acquire and correlate data from the Fermilab accelerator complex (NuMI), the NOνA near detector at the Fermilab site and the NOνA far detector which is located 810 km away at Ash River, MN. This system has unique properties that let it fully exploit the physics capabilities of the NOνA detector. The design of the NOνA DAQ system and its capabilities are discussed in this paper.

NOνA neutrino experiment status

The primary goal of the NOνA neutrino oscillation experiment is to study the probabilities of transformation of muonic-neutrinos into electron-neutrinos. The experiment is currently under construction and will use a 700 kW accelerator-based NuMI beam (Neutrinos at the Main Injector) and two detectors. The Near Detector (329 t at Fermi National Accelerator Laboratory, Illinois) and the Far Detector (14 kt, Ash River, Minnesota) are aligned to 14 mrad off-axis and separated by 810 km. They are made of active liquid scintillator and readout by avalanche photo-diodes. Recent results from world-wide neutrino experiments indicate that NOνA is in the position to determine the neutrino mass hierarchy as it is also searching for the first hints of CP violation in neutrino sector. The design, the goals and the current status of the NOνA experiment are presented here with the current estimates of its sensitivity to the mass hierarchy measurement.

NOvA: Current Status and Future Reach

NOνA, the NuMI Off-Axis νe Appearance experiment will study νμ→νe oscillations, characterized by the mixing angle θ13. A complementary pair of detectors will be constructed ∼14 mrad off beam axis to optimize the energy profile of the neutrinos. This system consists of a surface based 14 kTon liquid scintillatior tracking volume located 810 km from the main injector source (NuMI) in Ash River, Minnesota and a smaller underground 222 Ton near detector at the Fermi National Accelerator Laboratory (FNAL). The first neutrino signals at the Ash River site are expected soon after the completion of 2012 Fermilab accelerator upgrades. In the meantime, a near detector surface prototype has been completed and neutrinos from two sources at FNAL have been observed using the same highly segmented PVC and liquid scintillator detector system that will be deployed in the full scale experiment. With the recent measurements of θ13 as input, updated sensitivities of NOνAʼs capability to ultimately determine the ordering of the neutrino masses and measure CP violation in neutrino oscillations will be provided. Additionally, design and initial performance characteristics of the surface prototype system along with implications for the full NOνAprogram will be presented.

NOνA detector technology with initial performance from the surface prototype

NOνA, the NuMI Off-Axis νe Appearance experiment, will study νμ → νe oscillations characterized by the mixing angle θ13. Provided θ13 is large enough, NOνA may ultimately determine the ordering of the neutrino masses and measure CP violation in neutrino oscillations. A complementary pair of detectors will be constructed ~14 mrad off beam axis to optimize the energy profile of the neutrinos. This system consists of a surface based 14 kTon liquid scintillatior tracking volume located 810 km from the main injector source (NuMI) in Ash River, Minnesota and a smaller underground 222 Ton near detector at the Fermilab. The first neutrino signals at the Ash River Site are expected prior to the 2012 accelerator shutdown. In the meantime, a near detector surface prototype has been completed and neutrinos from two Fermilab sources have been observed using the same highly segmented PVC and liquid scintillator detector system that will be deployed in the full scale experiment. Design and initial performance characteristics of this prototype system are being fed back into the design for the full NOνA program.

The NOvA experiment: status and outlook

The NOvA long-baseline neutrino oscillation experiment is currently under construction and will use an upgraded NuMI neutrino source at Fermilab and a 14-kton detector at Ash River, Minnesota to explore the neutrino sector. NOvA uses a highly active, finely segmented detector design that offers superb event identification capability, allowing precision measurements of νe/ν¯e appearance and νμ/ν¯μ disappearance, through which NOvA will provide constraints on θ13, θ23, |Δmatm2|, the neutrino mass hierarchy, and the CP-violating phase δ. In this article, we review NOvAʼs uniquely broad physics scope, including sensitivity updates in light of the latest knowledge of θ13, and we discuss the experimentʼs construction and operation timeline.

The NOvA Data Acquisition System

The NOvA experiment is a long baseline neutrino experiment designed to make key measures to determine the neutrino mass hierarchy, neutrino mixing and CP violation in the neutrino sector. In order to make these measurements the NOvA collaboration has designed a highly distributed, synchronized, continuous digitization and readout system that is able to acquire and correlate data from the Fermilab accelerator complex, the NOvA near detector at Fermilab and the NOvA far detector which is located 810 km away at Ash River, MN. This system has unique properties that let it fully exploit the physics capabilities of the NOvA detector. This paper discusses the design of the NOvA DAQ system and its capabilities.

Synthesis of geopolymers from volcanic ash via the alkaline fusion method: Effect of Al2O3/Na2O molar ratio of soda–volcanic ash

The alkaline fusion method was used to enhance the reactivity of volcanic ash for geopolymer synthesis. To that end, different mixtures of fused soda–volcanic ash (fused volcanic ash) were used to assess reactivity for geopolymer synthesis. The amount of amorphous phase was determined both in the volcanic ash and the fused volcanic ash and X-ray diffraction analysis was used to evaluate effect of the alkaline fusion method. Different geopolymer mortars were prepared by alkaline activation of mixtures of powders of fused volcanic ash and metakaolin and river sand using sodium silicate as activator. Metakaolin was considered as consumer of excess of alkali contained in the fused volcanic ash. The geopolymer mortars were characterized by determination of setting time, linear shrinkage, compressive strength and scanning electron microscopy. The amount of amorphous phase and excess of fused soda content of the fused volcanic ash depended on molar ratio of Al2O3/Na2O and played a key role for geopolymer synthesis. The most convenient Al2O3/Na2O molar ratio of fused volcanic ash to produce effective geopolymer mortars ranged between 0.13 and 0.18. This study showed that volcanic ash can be used successfully as an alternative raw material for production of geopolymers via alkaline activation of fused volcanic ash.