1,767 research outputs found
Smart Asset Management for Electric Utilities: Big Data and Future
This paper discusses about future challenges in terms of big data and new
technologies. Utilities have been collecting data in large amounts but they are
hardly utilized because they are huge in amount and also there is uncertainty
associated with it. Condition monitoring of assets collects large amounts of
data during daily operations. The question arises "How to extract information
from large chunk of data?" The concept of "rich data and poor information" is
being challenged by big data analytics with advent of machine learning
techniques. Along with technological advancements like Internet of Things
(IoT), big data analytics will play an important role for electric utilities.
In this paper, challenges are answered by pathways and guidelines to make the
current asset management practices smarter for the future.Comment: 13 pages, 3 figures, Proceedings of 12th World Congress on
Engineering Asset Management (WCEAM) 201
Field tuned critical fluctuations in YFe2Al10: Evidence from magnetization, 27Al (NMR, NQR) investigations
We report magnetization, specific heat, and NMR investigations on YFe2Al10
over a wide range in temperature and magnetic field and zero field (NQR)
measurements. Magnetic susceptibility, specific heat and spin-lattice
relaxation rate divided by T (1/T1T) follow a weak power law (T^-0.4)
temperature dependence, which is a signature of critical fluctuations of Fe
moments. The value of the Sommerfeld-Wilson ratio and linear relation between
1/T1T and chi(T) suggest the existence of ferromagnetic correlations in this
system. No magnetic ordering down to 50 mK in Cp(T) and the unusual temperature
and field scaling of the bulk and NMR data are associated with a magnetic
instability which drives the system to quantum criticality. The magnetic
properties of the system are tuned by field wherein ferromagnetic fluctuations
are suppressed and a crossover from quantum critical to FL behavior is observed
with increasing magnetic field
Spin liquid behaviour in Jeff=1/2 triangular lattice Ba3IrTi2O9
Ba3IrTi2O9 crystallizes in a hexagonal structure consisting of a layered
triangular arrangement of Ir4+ (Jeff=1/2). Magnetic susceptibility and heat
capacity data show no magnetic ordering down to 0.35K inspite of a strong
magnetic coupling as evidenced by a large Curie-Weiss temperature=-130K. The
magnetic heat capacity follows a power law at low temperature. Our measurements
suggest that Ba3IrTi2O9 is a 5d, Ir-based (Jeff=1/2), quantum spin liquid on a
2D triangular lattice.Comment: 10 pages including supplemental material, to be published in Phys.
Rev. B (Rapid Comm.
A REVIEW ARTICLE ON KRIMI WITH CONTEMPORARY ASSESSMENT
Krimi exist its importance in Medical science from ages. Starting from Rig Veda to Samhita Krimi is accepted as a causative factor of diseases. Though there is mention of non-pathological Krimi in the texts, but elaboration not done. Whereas, there is wide narration of pathological Krimi found in different Samhita. Description of etiologies, habitat, nomenclature, morphology, and clinical conditions produced due to Krimi is done by different Acharyas. The clinical conditions produced due to Krimi in host may be broadly categorized under GIT ailments, skin ailments and features of Anemia. Regarding management of Krimi, there is sufficient explanation of treatment principles in Samhita. Various research works have been done concerning treatment aspects of Krimi. These clinical studies emphasize the effect of herbal, mineral or herbomineral drug preparations on certain parasite or protozoan. Only few studies have been done in Ayurveda to find out the type of Krimi infection/infestation based on the division of Krimi. Some research workers had tried to correlate the Krimi with few parasites only. The correlation of Krimi with the contemporary infectious microbes may be done by examining the resemblance of their habitat, morphology and effect on host. But it is a difficult task to correlate Krimi with modern due to lack of detail description of individual Krimi. Under the word Krimi all micro organisms like bacteria, virus, parasite, and fungus can be included. In this article effort has been made to describe the concept of Krimi from different Ayurvedic treatises and also to correlate them with similar microbes and parasites based on their habitat and effect on human body
Bose-Einstein condensation of triplons in the S=1 tetramer antiferromagnet K2Ni2(MoO4)3: A compound close to quantum critical point
The structure of K2Ni2(MoO4)3 consists of S=1 tetramers formed by Ni^{2+}
ions. The magnetic susceptibility chi(T) and specific heat Cp(T) data on a
single crystal show a broad maximum due to the low-dimensionality of the system
with short-range spin correlations. A sharp peak is seen in chi(T) and Cp(T) at
about 1.13 K, well below the broad maximum. This is an indication of magnetic
long-range order i.e., the absence of spin-gap in the ground state.
Interestingly, the application of a small magnetic field (H>0.1 T) induces
magnetic behavior akin to Bose-Einstein condensation (BEC) of triplon
excitations observed in some spin-gap materials. Our results demonstrate that
the temperature-field (T-H) phase boundary follows a power-law
(T-T_{N})propotional to H^(1/alpha) with the exponent 1/alpha close to 2/3, as
predicted for BEC scenario. The observation of BEC of triplon excitations in
small H infers that K2Ni2(MoO4)3 is located in the proximity of a quantum
critical point, which separates the magnetically ordered and spin-gap regions
of the phase diagram.Comment: 5 pages, 5 figures, Accepted in Phys. Rev. B Rapid Communication
Magnetic properties and spin dynamics in single molecule paramagnets Cu6Fe and Cu6Co
The magnetic properties and the spin dynamics of two molecular magnets have
been investigated by magnetization and d.c. susceptibility measurements,
Electron Paramagnetic Resonance (EPR) and proton Nuclear Magnetic Resonance
(NMR) over a wide range of temperature (1.6-300K) at applied magnetic fields,
H=0.5 and 1.5 Tesla. The two molecular magnets consist of
CuII(saldmen)(H2O)}6{FeIII(CN)6}](ClO4)38H2O in short Cu6Fe and the analog
compound with cobalt, Cu6Co. It is found that in Cu6Fe whose magnetic core is
constituted by six Cu2+ ions and one Fe3+ ion all with s=1/2, a weak
ferromagnetic interaction between Cu2+ moments through the central Fe3+ ion
with J = 0.14 K is present, while in Cu6Co the Co3+ ion is diamagnetic and the
weak interaction is antiferromagnetic with J = -1.12 K. The NMR spectra show
the presence of non equivalent groups of protons with a measurable contact
hyperfine interaction consistent with a small admixture of s-wave function with
the d-function of the magnetic ion. The NMR relaxation results are explained in
terms of a single ion (Cu2+, Fe3+, Co3+) uncorrelated spin dynamics with an
almost temperature independent correlation time due to the weak magnetic
exchange interaction. We conclude that the two molecular magnets studied here
behave as single molecule paramagnets with a very weak intramolecular
interaction, almost of the order of the dipolar intermolecular interaction.
Thus they represent a new class of molecular magnets which differ from the
single molecule magnets investigated up to now, where the intramolecular
interaction is much larger than the intermolecular one
^31P NMR investigations on the ferromagnetic quantum critical system YbNi_4P_2
We studied the new heavy-fermion system YbNiP, which presents
strong ferromagnetic correlations, using the local P NMR probe over a
wide field (0.2-8.6 \textsf{T}) and temperature (1.8-200 K) range. P NMR
Knight shift provides the static spin susceptibility which tracks the bulk
susceptibility whereas the spin-lattice relaxation rate )
provide information about the fluctuations of the Yb 4f moment. The Korringa
law is valid over a wide range in temperature and field. The Korringa product
S) 1 gives evidence for the presence of strong
ferromagnetic correlations. Over two decades in temperature a behaviour was found.Comment: 5 pages, 4 figure
Signature of a randomness-driven spin-liquid state in a frustrated magnet
Collective behaviour of electrons, frustration induced quantum fluctuations
and entanglement in quantum materials underlie some of the emergent quantum
phenomena with exotic quasi-particle excitations that are highly relevant for
technological applications. Herein, we present our thermodynamic and muon spin
relaxation measurements, complemented by ab initio density functional theory
and exact diagonalization results, on the recently synthesized frustrated
antiferromagnet Li4CuTeO6, in which Cu2+ ions (S = 1/2) constitute disordered
spin chains and ladders along the crystallographic [101] direction with weak
random inter-chain couplings. Our thermodynamic experiments detect neither
long-range magnetic ordering nor spin freezing down to 45 mK despite the
presence of strong antiferromagnetic interaction between Cu2+ moments leading
to a large effective Curie-Weiss temperature of -154 K. Muon spin relaxation
results are consistent with thermodynamic results. The temperature and magnetic
field scaling of magnetization and specific heat reveal a data collapse
pointing towards the presence of random-singlets within a disorder-driven
correlated and dynamic ground-state in this frustrated antiferromagnet
Postoperative stereotactic radiosurgery compared with whole brain radiotherapy for resected metastatic brain disease (NCCTG N107C/CEC·3): a multicentre, randomised, controlled, phase 3 trial
Background Whole brain radiotherapy (WBRT) is the standard of care to improve intracranial control following resection of brain metastasis. However, stereotactic radiosurgery (SRS) to the surgical cavity is widely used in an attempt to reduce cognitive toxicity, despite the absence of high-level comparative data substantiating efficacy in the postoperative setting. We aimed to establish the effect of SRS on survival and cognitive outcomes compared with WBRT in patients with resected brain metastasis. Methods In this randomised, controlled, phase 3 trial, adult patients (aged 18 years or older) from 48 institutions in the USA and Canada with one resected brain metastasis and a resection cavity less than 5·0 cm in maximal extent were randomly assigned (1:1) to either postoperative SRS (12–20 Gy single fraction with dose determined by surgical cavity volume) or WBRT (30 Gy in ten daily fractions or 37·5 Gy in 15 daily fractions of 2·5 Gy; fractionation schedule predetermined for all patients at treating centre). We randomised patients using a dynamic allocation strategy with stratification factors of age, duration of extracranial disease control, number of brain metastases, histology, maximal resection cavity diameter, and treatment centre. Patients and investigators were not masked to treatment allocation. The co-primary endpoints were cognitive-deterioration-free survival and overall survival, and analyses were done by intention to treat. We report the final analysis. This trial is registered with ClinicalTrials.gov, number NCT01372774. Findings Between Nov 10, 2011, and Nov 16, 2015, 194 patients were enrolled and randomly assigned to SRS (98 patients) or WBRT (96 patients). Median follow-up was 11·1 months (IQR 5·1–18·0). Cognitive-deterioration-free survival was longer in patients assigned to SRS (median 3·7 months [95% CI 3·45–5·06], 93 events) than in patients assigned to WBRT (median 3·0 months [2·86–3·25], 93 events; hazard ratio [HR] 0·47 [95% CI 0·35–0·63]; p<0·0001), and cognitive deterioration at 6 months was less frequent in patients who received SRS than those who received WBRT (28 [52%] of 54 evaluable patients assigned to SRS vs 41 [85%] of 48 evaluable patients assigned to WBRT; difference −33·6% [95% CI −45·3 to −21·8], p<0·00031). Median overall survival was 12·2 months (95% CI 9·7–16·0, 69 deaths) for SRS and 11·6 months (9·9–18·0, 67 deaths) for WBRT (HR 1·07 [95% CI 0·76–1·50]; p=0·70). The most common grade 3 or 4 adverse events reported with a relative frequency greater than 4% were hearing impairment (three [3%] of 93 patients in the SRS group vs eight [9%] of 92 patients in the WBRT group) and cognitive disturbance (three [3%] vs five [5%]). There were no treatment-related deaths. Interpretation Decline in cognitive function was more frequent with WBRT than with SRS and there was no difference in overall survival between the treatment groups. After resection of a brain metastasis, SRS radiosurgery should be considered one of the standards of care as a less toxic alternative to WBRT for this patient population. Funding National Cancer Institute
- …