bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fabrication, characterization and micromechanics modeling of the electrical conductivity of reduced graphene oxide/aramid nanofiber nanocomposites
Authors: Zhou Tianyang , Boyd James G , Loufakis Dimitrios , Lutkenhaus Jodie L , Lagoudas Dimitris C 
Published: June 2019

Abstract
Graphene-based materials with high graphene concentration are of great interest for multifunctional, structural electrode materials that simultaneously store electrical energy and carry structural loads. Graphene-based materials can have a high electrochemically active surface area, high electrical conductivity, and good stiffness and strength. Published analytical studies of electrical conductivity are mostly focused on graphene-based polymer nanocomposites with very low concentrations of conductive fillers, for percolation purposes. In the research reported herein, reduced graphene oxide (rGO) and aramid nanofiber (ANF) nanocomposite films with higher concentrations of rGO, up to 100 wt% rGO, were fabricated and characterized for their electrical conductivity. In addition, a hybrid micromechanical and phenomenological model of electrical conductivity was developed to include the effects of rGO waviness and conductivity, volume fraction of ANF, random orientation of rGO and ANFs, interphase thickness and interphase conductivity. The experimentally measured in-plane conductivity of rGO/ANF nanocomposite films decreases exponentially with the addition of ANFs. For example, the experimental in-plane conductivity of rGO/ANF nanocomposite films was increased 30-fold by decreasing the ANF loading from 25 wt% to 0 wt%. This exponential relationship can be explained by the model proposed. The model showed that the influence of the interphase thickness and interphase conductivity was more significant than that of waviness. The effective in-plane conductivity changed by 20% when the waviness was decreased from maximum observed value to minimum. The effective in-plane conductivity decreased by two orders of magnitude when the interphase thickness was changed from 0 to 0.5 nm and the interphase conductivity was 0.09 S m−1. The model results agreed with the experimental data when the interphase thickness and conductivity vary with the volume fraction of rGO. The addition of ANFs is significant due to the influence it has on the microstructure of the composite and the interphase structure and conductivity. This model can be used for composites with coated fibers or continuous polymeric matrix by adjusting the interphase morphology.
What do we know about soil carbon destabilization?
Authors: Bailey Vanessa L , Pries Caitlin Hicks , Lajtha Kate 
Published: June 2019

Abstract
Most empirical and modeling research on soil carbon (C) dynamics has focused on those processes that control and promote C stabilization. However, we lack a strong, generalizable understanding of the mechanisms through which soil organic carbon (SOC) is destabilized in soils. Yet a clear understanding of C destabilization processes in soil is needed to quantify the feedbacks of the soil C cycle to the Earth system. Destabilization includes processes that occur along a spectrum through which SOC shifts from a ‘protected’ state to an ‘available’ state to microbial cells where it can be mineralized to gaseous forms or to soluble forms that are then lost from the soil system. These processes fall into three general categories: (1) release from physical occlusion through processes such as tillage, bioturbation, or freeze-thaw and wetting-drying cycles; (2) C desorption from soil solids and colloids; and (3) increased C metabolism. Many processes that stabilize soil C can also destabilize C, and C gain or loss depends on the balance between competing reactions. For example, earthworms may both destabilize C through aggregate destruction, but may also create new aggregates and redistribute C into mineral horizon. Similarly, mycorrhizae and roots form new soil C but may also destabilize old soil C through priming and promoting microbial mining; labile C inputs cause C stabilization through increased carbon use efficiency or may fuel priming. Changes to the soil environment that affect the solubility of minerals or change the relative surfaces charges of minerals can destabilize SOC, including increased pH or in the reductive dissolution of Fe-bearing minerals. By considering these different physical, chemical, and biological controls as processes that contribute to soil C destabilization, we can develop thoughtful new hypotheses about the persistence and vulnerability of C in soils and make more accurate and robust predictions of soil C cycling in a changing environment.
Seasonal hydroclimatic ensemble forecasts anticipate nutrient and suspended sediment loads using a dynamical-statistical approach
Authors: Sharma Sanjib , Gall Heather , Gironás Jorge , Mejia Alfonso 
Published: June 2019

Abstract
Subseasonal-to-seasonal (S2S) water quantity and quality forecasts are needed to support decision and policy making in multiple sectors, e.g. hydropower, agriculture, water supply, and flood control. Traditionally, S2S climate forecasts for hydroclimatic variables (e.g. precipitation) have been characterized by low predictability. Since recent next-generation S2S climate forecasts are generated using improved capabilities (e.g. model physics, assimilation techniques, and spatial resolution), they have the potential to enhance hydroclimatic predictions. Here, this is tested by building and implementing a new dynamical-statistical hydroclimatic ensemble prediction system. Dynamical modeling is used to generate S2S flow predictions, which are then combined with quantile regression to generate water quality forecasts. The system is forced with the latest S2S climate forecasts from the National Oceanic and Atmospheric Administration’s Climate Forecast System version 2 to generate biweekly flow, and monthly total nitrogen, total phosphorus, and total suspended sediment loads. By implementing the system along a major tributary of the Chesapeake Bay, the largest estuary in the US, we demonstrate that the dynamical-statistical approach generates skillful flow, nutrient load, and suspended sediment load forecasts at lead times of 1–3 months. Through the dynamical-statistical approach, the system comprises a cost and time effective solution to operational S2S water quality prediction.
An overview of handheld sun photometer measurements of atmospheric aerosols in New Orleans, Louisiana: A case study of the Xavier university study site
Authors: Bradley M , Sevalia B , Gasseller M 
Published: June 2019

Abstract
Aerosol optical depth (AOT) was measured at Xavier University of Louisiana (XULA, 29.96° N, 90.11° W and 3m above sea level) using a GLOBE handheld sun photometer. The measurements were done at two different wavelengths, 505nm and 625nm. The measured values were used to extrapolate the AOT values for wavelengths 667nm, 551nm, 532nm and 490nm at the XULA site. The measured and calculated AOT values were then compared with values from the nearest AERONET station at Wave CIS site 6 (AERONET, 28.87° N, 90.48° W and 33m above sea level), which is 60 miles south of XULA. In this study we tracked the annual and daily variations of AOT for a 12-month period from September 2017 to August 2018. These data show good qualitative agreement between the two stations in the 12-month period. Both sets of data show distinct peaks in February and May. Both sets of data show low AOT values in the winter months and high AOT values in the summer months. The hourly AOT variations averaged over the 12-month period was also investigated for the XULA site. The data show two peaks, one at 9:00 am and another at 3:00pm. We also compared AOT data from two independently calibrated GLOBE sun photometers at the XULA site. The data show that the two instruments are in excellent agreement. The R-squared value for the 505nm channel is 0.92 and the R-squared value for the 625nm channel is 0.95.
Experimental investigation of hydrodynamics and heat transfer of sphere cooling using air/water mist two phase flow
Authors: Abed A H , Shcheklein S E , Pakhaluev V M 
Published: June 2019

Abstract
To improve the cooling performance for the future generation of gas-cooled equipment, experimental studies on air/water mist heat transfer of single sphere inside a cylindrical channel have been carried out with an aim to investigate the heat transfer enhancement by suspending tiny water mist into air flow. The effect of the different key factors such the inlet Reynolds number, surface heat flux and water flux density on friction flow and heat transfer characteristics are examined. Experiments were performed in five cases using air as well as air/water mist two phase flow as working coolant for range of water flux density (j = 23.39 - 111.68 kg m-2 hr-1). The results obtained from the related experimental work revealed that the presence of water mist leads to a significant increase in heat transfer over the use of air coolant alone. The Nusselt numbers are respectively 1%, 19.7%, 90.2% and 134% higher than those in single phase - cooling for all cases of water flux density respectively. It was also found that the water flux density has little influence on friction factor. When the surface heat flux is fixed, the heat transfer enhancement factor increases with the increasing of water flux density.
The device for monitoring the LED display high-voltage insulators state
Authors: Balobanov R N , Zaripov D K , Akhmadeev A A 
Published: June 2019

Abstract
The article discusses the possibility of using devices for monitoring the state of highvoltage insulators with LED indication, mounted on insulating structures of high-voltage lines and substations. The scheme of the device is given and its principle of operation is described. The feasibility of indicating the early stage of the an insulation defect development in a laboratory and full-scale experiments on real power system facilities using devices with LED indication are shown. A new method of insulation control using the developed device will allow, when visually inspecting an overhead line, to additionally provide information about the change in the electric field and the appearance of discharges in the insulation. In addition to the early warning of the birth of a defect, this information will be useful for routine maintenance (cleaning) of insulators.
On the forecasting of trends of specific mixed loads of electric consumers of microdistricts and cities change in the conditions of inadequate data
Authors: Gasho E G , Guzhov S V , Krolin A A 
Published: June 2019

Abstract
The paper gives a brief analysis of modern methods of analysis, confirmation and prediction of specific mixed loads of electric consumers in housing estates and cities and formulates the main problems afflicting the reorganization of the industry, taking into account the requirements of digitalization of the economy. In order to identify the advantages and disadvantages of various solutions for optimizing the compilation of energy balances, a mathematical model is constructed, which allows analyzing the needs of microdistricts and cities in electrical energy and realizes the forecast of the development of urban energy systems in different socio-economic and climatic conditions.
Methodology of GHG emissions assessment caused at the construction of energy facilities. Case study: Hydropower
Authors: Avilova I P , Naumov A E , Krutilova M O 
Published: June 2019

Abstract
As energy is the main ‘fuel’ for social and economic development, and since energy-related activities have significant environmental impacts, it is important to lower emissions and stabilize atmospheric CO2 levels to avoid the worst predicted effects of climate change. Reducing energy consumption and costs is becoming central to planning, construction, and use of energy construction facilities from an environmental and economic point of view. Each energy source has advantages and disadvantages referred to: operating costs, environmental impact, and other factors. Each generation method produces some greenhouse gases (GHG) in varying quantities through construction, operation, and decommissioning. Some generation methods like coal fired plants release the majority of GHGs during operation. Others, such as wind power and hydro power release the majority of emissions during construction and decommissioning. Normalizing the lifecycle emissions with electrical generation allows a fair comparison of different generation methods on a per gigawatt-hour basis.
Determination of tensile strength of brittle materials by bending thin discs on the annular support
Authors: Goltsev V Y , Gribov N A 
Published: June 2019

Abstract
It is proposed to use the test of bending small thin disk specimens simply supported along the contour, to determine the resistance of material to tensile strain. The results of computer analysis of stress-strain state and test a thin disk specimens made of brittle materials are cast iron and graphite as a possible model, and directly samples made by electric pulse methods are presented. It is shown the effect of size of specimens on the resistance to their destruction and different character of deformation and destruction of cast iron and graphite samples. The possibility of application of thin disc samples for the determination the resistance to tensile strain of the composite ceramics based on SiAlON with various additives Y2O3, SiC, and TiN is confirmed.
Processing of mineral raw materials and production wastes by combustion under atmospheric conditions
Authors: Loryan V E , Kachin A R , Khomenko N Yu 
Published: June 2019

Abstract
The work considers the regularities of SHS of ferrotitanium, ferrochromium and synthetic mica-based fluorophlogopite. The powder mixture of minerals (silica sand, Karelian shungite, ilmenite, chromium concentrate from Shorzha) and secondary raw materials (recirculated cryolite) with metal reducing agents and KClO4 energy additive were used for the synthesis. The regularities of the initial mixture combustion under atmospheric conditions, the synthesized product composition and structure were investigated. Low-carbon ferrochromium with carbon content of 0.2%, ferrotitanium of the composition close to that of the industrial FeTi30 and synthetic mica-fluorophlogopite were synthesized. The synthesis of porous and molten-cast materials based on fluorophlogopite is shown to be possible. The composite material of K(Na)Mg3AlSi3O10Fe2-MgAl2O4-SiC was synthesized.
Features of the synthesis and consolidation of MeIVB2– (MeIV, Mo)Si2 ceramic powder for high-temperature applications
Authors: Pogozhev Yu S , Lemesheva M V , Potanin A Yu , Vershinnikov V I , Levashov E A 
Published: June 2019

Abstract
ZrB2–ZrSi2–MoSi2 and HfB2–HfSi2–MoSi2 composite ceramic powders were obtained by magnesiothermic SHS. The synthesized powders were consolidated by hot pressing in the temperature range of 1200-1250°C at 30 MPa. The structure and phase composition of the powders and compact ceramics were studied by X-ray powder diffraction analysis and scanning electron microscopy. ZrB2/HfB2, ZrSi2/HfSi2, ZrSi, and MoSi2 were the key phases of the ceramic powders and sintered ceramics. The average grain size of the powders after grinding was 6–8 μm. Saturation of the ZrSi phase with silicon and increased ZrSi2 content were observed during hot pressing. The dense ceramics had a residual porosity of 1.1–7.4%, which was largely dependent on the contents of silicides in SHS powders.
Simulation of spatial ordering of powder mixture particles when packed in square matrices using an example of monodisperse balls
Authors: Ponomarev M A , Loryan V E 
Published: June 2019

Abstract
The peculiarities of self-ordering of large particles of powder mixture components with layer-by-layer pressing of long billets used in material production by the method of self-propagating high-temperature synthesis (SHS) are studied using the example of structure formation at compaction of thin layers of a model system of monodisperse calibrated solid balls (1 mm in diameter). In unilateral axial compaction, the case of packing of thin layers of balls (containing 1–5 monolayers) in a square matrix (with a ratio of the transverse dimension of the matrix to the diameter of the ball ∼14) is considered at low pressures that do not cause significant deformation of the balls. In the disperse system under study, a structural ordering of the particles occurs with a characteristic stepped view of the curve of the compact height dependence on the number of balls in the initial charge of balls. With an increase in the number of balls in the charge, the density of thin layers changes periodically during the compaction. In the compacts, fragments of structures in which the particles are arranged orderly like regular packing of ideal balls appear. The square shape of the matrix provides the formation of fragments of rhombohedral and cubic packing. The influence of nonuniform distribution of the initial charge of balls inside the matrix on the structuring of thin layers during compaction is considered.
Electroconductivity of Al2O3/graphene nanocomposite processed by SPS technique
Authors: Sanchez-Bolinchez A , Klyatskina E , Segovia-Lopez F , Zholnin A G , Stolyarov V V 
Published: June 2019

Abstract
Electrical conductivity (σ), relative dielectric permittivity (εr) and dissipation factor (D) measured in graphene-alumina composites. Samples obtained by plasma spark sintering (SPS) from a mixture of raw powders: δ-alumina (36 nm average particle size) and graphene flakes (3 nm thickness and 2–3 μm length). Graphene content in samples was 0, 1 and 2% by weight. The study carried out for frequencies from 50 Hz to 100 kHz. Both c and εr were higher for Al2O3–2% graphene: up to 90 μS/m and 19 respectively; while alumina with 1% graphene showed similar values to the pure alumina samples: 50 μS/m to electrical conductivity and 16 to relative permittivity. The dissipation factor was similar in the three materials tested. D increased with the frequency, reaching high values (0.7) at 100 kHz. Composites with 1 and 2% graphene content showed a dissimilar dielectric behavior with the frequency. Alumina reflected a classical behavior of the permittivity dependence with the frequency. Graphene composites also show the same behavior at frequencies above 100 Hz. Below this frequency, the presence of graphene increases the relative permittivity to exceed that from pure alumina. The graphene content leads to rise of relative permittivity, which means easier polarizability.
2D MoS2 nanopores: ionic current blockade height for clustering DNA events
Authors: Diaz Carral Angel , Shekar Sarap Chandra , Liu Ke , Radenovic Aleksandra , Fyta Maria 
Published: June 2019

Abstract
2D nanopores can be used to electrophoretically drive DNA molecules, which can in turn be identified through measurable electronic current blockades. In this work, we use experimental data from molybdenum disulfide nanopores threading DNA nucleotides and propose a methodological approach to interpret DNA events. Specifically, the experimental ionic traces are used to train an unsupervised machine learning model for identifying distinct molecular events through the 2D nanopore. For the first time, we propose a clustering of experimental 2D nanopore data based on the ionic current blockade height and unrelated to the traditional dwell time for each DNA event. Within this approach, the blockade level information is implicitly included in the feature space analysis and does not need to be treated explicitly. We could show the higher efficiency of the blockade height over the traditional dwell time also in coping with sparse nanopore data sets. Our approach allows for a deep insight into characteristic molecular features in 2D nanopores and provides a feedback mechanism to tune these materials and interpret the measured signals. It has, thus, a high impact on the efficiency of 2D nanopore-based DNA sequencers.
Engineering the interface chemistry for scandium electron contacts in WSe2 transistors and diodes
Authors: Smyth Christopher M , Walsh Lee A , Bolshakov Pavel , Catalano Massimo , Schmidt Michael , Sheehan Brendan , Addou Rafik , Wang Luhua , Kim Jiyoung , Kim Moon J , Young Chadwin D , Hinkle Christopher L , Wallace Robert M 
Published: June 2019

Abstract
Sc has been employed as an electron contact to a number of two-dimensional (2D) materials (e.g. MoS2, black phosphorous) and has enabled, at times, the lowest electron contact resistance. However, the extremely reactive nature of Sc leads to stringent processing requirements and metastable device performance with no true understanding of how to achieve consistent, high-performance Sc contacts. In this work, WSe2 transistors with impressive subthreshold slope (109 mV dec−1) and I
ON/I
OFF (106) are demonstrated without post-metallization processing by depositing Sc contacts in ultra-high vacuum (UHV) at room temperature (RT). The lowest electron Schottky barrier height (SBH) is achieved by mildly oxidizing the WSe2
in situ before metallization, which minimizes subsequent reactions between Sc and WSe2. Post metallization anneals in reducing environments (UHV, forming gas) degrade the I
ON/I
OFF by ~103 and increase the subthreshold slope by a factor of 10. X-ray photoelectron spectroscopy indicates the anneals increase the electron SBH by 0.4–0.5 eV and correspondingly convert 100% of the deposited Sc contacts to intermetallic or scandium oxide. Raman spectroscopy and scanning transmission electron microscopy highlight the highly exothermic reactions between Sc and WSe2, which consume at least one layer RT and at least three layers after the 400 °C anneals. The observed layer consumption necessitates multiple sacrificial WSe2 layers during fabrication. Scanning tunneling microscopy/spectroscopy elucidate the enhanced local density of states below the WSe2 Fermi level around individual Sc atoms in the WSe2 lattice, which directly connects the scandium selenide intermetallic with the unexpectedly large electron SBH. The interface chemistry and structural properties are correlated with Sc–WSe2 transistor and diode performance. The recommended combination of processing conditions and steps is provided to facilitate consistent Sc contacts to WSe2.
Animal Ethics and Behavioral Science: An Overdue Discussion
Authors: Webb Christine E , Woodford Peter , Huchard Elise 
Published: June 2019

AbstractAnimal ethics—the field of philosophy concerned with the moral status of animals—is experiencing a momentum unprecedented in its history. Surprisingly, animal behavior science remains on the sidelines, despite producing critical evidence on which many arguments in animal ethics rest. In the present article, we explore the origins of the divide between animal behavior science and animal ethics before considering whether behavioral scientists should concern themselves with it. We finally envision tangible steps that could be taken to bridge the gap, encouraging scientists to be aware of, and to more actively engage with, an ethical revolution that is partly fueled by the evidence they generate.
A Life-Course Analysis of Engagement in Violent Extremist Groups
Authors: Carlsson Christoffer , Rostami Amir , Mondani Hernan , Sturup Joakim , Sarnecki Jerzy , Edling Christofer 
Published: June 2019

AbstractIn this exploratory study, individuals’ processes of engagement in violent extremist groups are analysed by drawing from criminological life-course theory and narrative-based understandings of crime. Based on interviews with individuals who have participated in violent extremism, it is suggested that the process of engagement consists of three steps: (1) a weakening of informal social controls, followed by (2) an interaction with individuals in proximity to the group and (3) a stage of meaning-making in relation to the group and one’s identity, resulting in an individual’s willingness and capacity to engaging in the group’s activities, including violence. In future theorizing about processes of engagement in violent extremism, the meanings of age, and the life-course stages of late adolescence and emerging adulthood in particular, should be given analytic attention.