4,359 research outputs found
Optimization of heat treatment of TRIP steels
In transformation induced plasticity (TRIP) steels, proper microstructure is essential. The TRIP effectprovides the material with high plasticity owing to high volume fraction of ductile phases (ferrite andaustenite) in microstructure. In consequence, it provides high hardening through deformation andtransformation. The hardening is caused by transformation of retained austenite to martensite. Suitablemicrostructure for TRIP effect can be obtained by either thermomechanical or heat treatment. Presentpaper describes development of an intercritical annealing technology, which guarantees fine-grainedmicrostructure formation consisting of appropriate fractions of ferrite, lower bainite and retainedaustenite. Such structure is suitable for further cold forming with TRIP effect hardening
Loneliness in the United States: A 2018 National Panel Survey of Demographic, Structural, Cognitive, and Behavioral Characteristics
Purpose: To inform health behavior intervention design, we sought to quantify loneliness and its correlates, including social media use, among adults in the United States. Design: Cross-sectional research panel questionnaire. Setting: Responses were gathered from individuals in all 50 states surveyed via Internet from February 2018 to March 2018. Participants: A total of 20 096 US panel respondents aged 18þ. Measures: The University of California at Los Angeles (UCLA) Loneliness Scale (theoretical score range ¼ 20-80) was administered along with demographic, structural, cognitive, and behavioral items. Analysis: After calibrating the sample to population norms, we conducted multivariable linear regression analysis. Results: The overall mean survey-weighted loneliness score was 44.03 (standard error ¼ 0.09). Social support (standardized b [sb] ¼ 0.19) and meaningful daily interactions (sb ¼ 0.14) had the strongest associations with lower loneliness, along with reporting good relationships, family life, physical and mental health, friendships, greater age, being in a couple, and balancing one’s daily time. Social anxiety was most strongly associated with greater loneliness (sb ¼ þ0.20), followed by self-reported social media overuse (sb ¼ þ0.05) and daily use of text-based social media (sb ¼ þ0.03). Conclusion: Our findings confirm that loneliness decreases with age, and that being in a relationship as well as everyday behavioral factors in people’s control are most strongly related to loneliness. Population health promotion efforts to reduce loneliness should focus on improving social support, decreasing social anxiety, and promoting healthy daily behaviors
Overview of APEX Project Results
The APEX mother-daughter project (Active Plasma EXperiments) was launched into an elliptical polar orbit (440–3,080 km) in December 1991. It consisted of the main Russian Interkosmos–25 (IK–25) satellite and the Czech MAGION–3 subsatellite, both with international scientific payloads. The mission used intensive modulated electron beam emissions and xenon plasma or neutral releases from the main satellite for studies of dynamic processes in the magnetosphere and upper ionosphere. Its main scientific objectives were to simulate an artificial aurora and to study optical and radio emissions from the aurora region, and to investigate the dynamics and relaxation of modulated electron and plasma jets, artificially injected into the ionospheric plasma. The experiments studied the Critical Ionization Velocity phenomenon and a diamagnetic cavity formation during the xenon releases, local and distant effects of the electron beam injection, spacecraft charging and potential balance, and plasma-wave interactions during the artificial emissions. Attempts were performed to utilize the modulated electron beam as an active transmitting antenna in the space. The theory of ballistic wave propagation across plasma barrier was tested in a joint active experiment with the Dushanbe ionospheric heater facility. In the paper, we give a short overview of the IK–25/MAGION–3 scientific instrumentation and methodology of experiments with artificial beam injections and we provide a review of the main APEX active experiments results, many of which have been published only in the Russian language so far. From a historical 25-years-long perspective, we try to put the results of the APEX experiments into the context of other active experiments in the space plasma
Plate tectonics of virus shell assembly and reorganization in phage φ8, a distant relative of mammalian reoviruses
The hallmark of a virus is its capsid, which harbors the viral genome and is formed from protein subunits, which assemble following precise geometric rules. dsRNA viruses use an unusual protein multiplicity (120 copies) to form their closed capsids. We have determined the atomic structure of the capsid protein (P1) from the dsRNA cystovirus Φ8. In the crystal P1 forms pentamers, very similar in shape to facets of empty procapsids, suggesting an unexpected assembly pathway that proceeds via a pentameric intermediate. Unlike the elongated proteins used by dsRNA mammalian reoviruses, P1 has a compact trapezoid-like shape and a distinct arrangement in the shell, with two near-identical conformers in nonequivalent structural environments. Nevertheless, structural similarity with the analogous protein from the mammalian viruses suggests a common ancestor. The unusual shape of the molecule may facilitate dramatic capsid expansion during phage maturation, allowing P1 to switch interaction interfaces to provide capsid plasticity
Long-term variations in solar wind parameters, magnetopause location, and geomagnetic activity over the last five solar cycles
We use both solar wind observations and empirical magnetopause models to reconstruct time series of the magnetopause standoff distance for nearly five solar cycles. Since the average annual interplanetary magnetic field (IMF) Bz is about zero, and the annual IMF cone angle varies between 54.0° and 61.2°, the magnetopause standoff distance on this time scale depends mostly on the solar wind dynamic pressure. The annual IMF magnitude well correlates with the sunspot number (SSN) with a zero time lag, while the annual solar wind dynamic pressure (Pdyn) correlates reasonably well with the SSN but with 3 years time lag. At the same time, we find an anticorrelation between Pdyn and SSN in cycles 20–21 and a correlation in cycles 22–24 with 2 years time lag. Both the annual solar wind density and velocity well correlate with the dynamic pressure, but the correlation coefficient is higher for density than for velocity. The 11‐year solar cycles in the dynamic pressure variations are superimposed by an increasing trend before 1991 and a decreasing trend between 1991 and 2009. The average annual solar wind dynamic pressure decreases by a factor of three from 1991 to 2009. Correspondingly, the predicted standoff distance in Lin et al.’s (2010) magnetopause model increases from 9.7 RE in 1991 to 11.6 RE in 2009. The annual SSN, IMF magnitude and magnetospheric geomagnetic activity indices display the same trends as the dynamic pressure. We calculate extreme solar wind parameters and magnetopause standoff distance in each year using daily values and find that both extremely small and large standoff distances during a solar cycle preferably occur at solar maximum r0061ther than at solar minimum
Super fast plasma streams as drivers of transient and anomalous magnetospheric dynamics
Abstract. We present multi spacecraft measurements in the magnetosheath (MSH) and in the solar wind (SW) by Interball, Cluster and Polar, demonstrating that coherent structures with magnetosonic Mach number up to 3 – Supermagnetosonic Plasma Streams (SPS) – generate transient and anomalous boundary dynamics, which may cause substantial displacements of the magnetospheric boundaries and the riddling of peripheral boundary layers. In this regard, for the first time, we describe a direct plasma penetration into the flank boundary layers, which is a candidate for being the dominant transport mechanism for disturbed MSH periods. Typically SPS's have a ram pressure exceeding by several times that of the SW and lead to long-range correlations between processes at the bow shock (BS) and at the magnetopause (MP) on one side and between MSH and MP boundary layers on the other side. We demonstrate that SPS's can be observed both near the BS and near the MP and argue that they are often triggered by hot flow anomalies (HFA), which represent local obstacles to the SW flow and can induce the SPS generation as a means for achieving a local flow balance. Finally, we also discuss other causes of SPS's, both SW-induced and intrinsic to the MSH. SPS's appear to be universal means for establishing a new equilibrium between flowing plasmas and may also prove to be important for astrophysical and fusion applications
Harmonizing methods to account for soil nitrous oxide emissions in Life Cycle Assessment of agricultural systems
CONTEXT: Worldwide greenhouse gas emissions (GHG) reached 59 Gt of COeq in 2019 and agricultural soils are the primary source of NO emissions. Life cycle assessments (LCA) have been successful in assessing GHG from agricultural systems. However, no review and harmonization attempt has been focused on soil NO emissions, despite the need to improve LCA methodologies for assessing GHG in agricultural LCA. OBJECTIVE: We therefore undertook a review and harmonization of existing methods to account for soil NO emissions in LCA of agricultural systems and products: i) to compare current methods used in LCA; ii) to identify advantages and iii) disadvantages of each method in LCA; iv) to suggest recommendations for LCA of agricultural systems; v) to identify research needs and potential methodological developments to account for soil NO emissions in the LCA of agricultural systems. In this paper, we consider as soil NO emissions, those originated from soils in relation to fertilisers (organic and manufactured), crop residues, land use/land management change, grassland management, manure and slurry applications and from grazing animals. METHODS: The approach adopted was based on two anonymous expert surveys and a series of expert workshops (n = 21) to define general and specific criteria to review LCA methods for GHG emissions used in LCA of agricultural systems. A broad list of keywords and search criteria was used as the research involved GHG assessment in agricultural LCA. Reviewed papers and methodology were then assessed by LCA and soil NO emission experts (n = 14). RESULTS AND DISCUSSION: >25,000 scientific papers and reports were identified, 1175 were screened, 263 included in the final review and 31 scientific papers were related to soil NO emissions. The results showed that a high level of accuracy corresponded to a low level of applicability and vice versa, following the assessment framework developed in this work through participatory approaches. SIGNIFICANCE: The choice of LCA methods, critical for high quality LCA of agricultural systems, should be based on the assessment objectives, data availability and expertise of the LCA practitioner. However, it is preferable to use DNDC model after calibration and validation or direct field measurements, considering system effects. When necessary data are lacking, IPCC tier 2 methodology where available should be used, otherwise 2019 IPCC Tier 1 methodology. This LCA method development should be synchronous with improvements of quantification methods and the assessment of a wider range of agricultural management practices and systems.This research has been developed within the PATHWAYS project, funded by the European Union’s Horizon 2020 Research and Innovation Programme European Union through Horizon 2020 Research and Innovation Programme under grant agreement No 101000395
Hadron Energy Reconstruction for the ATLAS Calorimetry in the Framework of the Non-parametrical Method
This paper discusses hadron energy reconstruction for the ATLAS barrel
prototype combined calorimeter (consisting of a lead-liquid argon
electromagnetic part and an iron-scintillator hadronic part) in the framework
of the non-parametrical method. The non-parametrical method utilizes only the
known ratios and the electron calibration constants and does not require
the determination of any parameters by a minimization technique. Thus, this
technique lends itself to an easy use in a first level trigger. The
reconstructed mean values of the hadron energies are within of the
true values and the fractional energy resolution is . The value of the ratio
obtained for the electromagnetic compartment of the combined calorimeter is
and agrees with the prediction that for this
electromagnetic calorimeter. Results of a study of the longitudinal hadronic
shower development are also presented. The data have been taken in the H8 beam
line of the CERN SPS using pions of energies from 10 to 300 GeV.Comment: 33 pages, 13 figures, Will be published in NIM
Measurement of the cross-section and charge asymmetry of bosons produced in proton-proton collisions at TeV with the ATLAS detector
This paper presents measurements of the and cross-sections and the associated charge asymmetry as a
function of the absolute pseudorapidity of the decay muon. The data were
collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with
the ATLAS experiment at the LHC and correspond to a total integrated luminosity
of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements
varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the
1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured
with an uncertainty between 0.002 and 0.003. The results are compared with
predictions based on next-to-next-to-leading-order calculations with various
parton distribution functions and have the sensitivity to discriminate between
them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables,
submitted to EPJC. All figures including auxiliary figures are available at
https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13
Measurement of the production of a W boson in association with a charm quark in pp collisions at √s = 7 TeV with the ATLAS detector
The production of a W boson in association with a single charm quark is studied using 4.6 fb−1 of pp collision data at s√ = 7 TeV collected with the ATLAS detector at the Large Hadron Collider. In events in which a W boson decays to an electron or muon, the charm quark is tagged either by its semileptonic decay to a muon or by the presence of a charmed meson. The integrated and differential cross sections as a function of the pseudorapidity of the lepton from the W-boson decay are measured. Results are compared to the predictions of next-to-leading-order QCD calculations obtained from various parton distribution function parameterisations. The ratio of the strange-to-down sea-quark distributions is determined to be 0.96+0.26−0.30 at Q 2 = 1.9 GeV2, which supports the hypothesis of an SU(3)-symmetric composition of the light-quark sea. Additionally, the cross-section ratio σ(W + +c¯¯)/σ(W − + c) is compared to the predictions obtained using parton distribution function parameterisations with different assumptions about the s−s¯¯¯ quark asymmetry
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