bluuebunny/crossref_metadata_2025_split huggingface dataset:
Quantum nondemolition measurement based generation of entangled states in two Bose–Einstein condensates
Authors: Aristizabal-Zuluaga Juan E , Skobleva Iuliia , Richter Lars , Ji Yangxu , Mao Yuping , Kondappan Manikandan , Ivannikov Valentin , Byrnes Tim 
Published: April 2021

Abstract
We theoretically study a scheme for generating entanglement between two Bose–Einstein condensates (BECs). The scheme involves placing two BECs in the path of a Mach–Zehnder interferometer, where the coherent light interacts with the atoms due to a quantum nondemolition Hamiltonian. In contrast to standard approaches where a Holstein–Primakoff approximation is used, we use an exact wavefunction approach where the atoms can be initialized in an arbitrary state and the light–atom interaction times can be arbitrary. In the short time regime, it is possible to construct a very simple approximate theory for the overall effect of the scheme: amplitudes in the superposition between the two BECs with unequal spin eigenvalues are damped. We analyze the types of correlations, entanglement, Einstein–Podolsky–Rosen (EPR) steering, and Bell correlations that are produced and show that the state is similar to a spin-EPR state. Using a two-pulse sequence the correlations can be dramatically improved, where the state further approaches a spin-EPR state.
High-yield thermalized positronium at room temperature emitted by morphologically tuned nanochanneled silicon targets
Authors: Mariazzi S , Caravita R , Zimmer C , Rienäcker B , Camper A , Belov A , Bonomi G , Brusa R S , Castelli F , Consolati G , Doser M , Gjersdal H , Glöggler L T , Guatieri F , Haider S , Matveev V , Nebbia G , Nedelec P , Pagano D , Penasa L , Petracek V , Prelz F , Povolo L , Rhøne O M , Rotondi A , Sandaker H , Zurlo N 
Published: April 2021

Abstract
Nanochanneled silicon targets with high positron/positronium (Ps) conversion rate and efficient Ps cooling were produced. Morphological parameters of the nanochannels, such as their diameter and length, were adjusted to get a large fraction of thermalized Ps at room temperature being emitted into vacuum. Ps cooling measurements were conducted combining single-shot positron annihilation lifetime spectroscopy and Doppler spectroscopy of the 13S → 23P transition. 2γ–3γ annihilation ratio measurements were also performed to estimate the positron/Ps conversion efficiency. In a converter with nanochannel diameter of 7–10 nm and depth of 3.89 μm, ∼28% of implanted positrons with an energy of 3.3 keV was found to be emitted as Ps with a transverse kinetic energy of 11 ± 2 meV. The reduction of the nanochannels depth to 1.13 μm, without changing the nanochannel diameter, was found to result in a less efficient cooling, highlighting the presence of Ps reflection from the bottom end of nanochannels.
Automated assessment of a kinetic database for fcc Co–Cr–Fe–Mn–Ni high entropy alloys
Authors: Abrahams Katrin , Zomorodpoosh Setareh , Khorasgani Ahmadreza Riyahi , Roslyakova Irina , Steinbach Ingo , Kundin Julia 
Published: April 2021

Abstract
The development of accurate kinetic databases by parametrizing the composition and temperature dependence of elemental atomic mobilities, is essential for correct multicomponent calculations and simulations. In this work the automated assessment procedure for the establishment of CALPHAD-type kinetic databases is proposed, including the storage of raw data and assessment results, automatic weighting of data, parameter selection and automated reassessments. This allows the establishment of reproducible up-to-date databases. The proposed software, written in python, is applied to the assessment of a kinetic database for the fcc Co–Cr–Fe–Mn–Ni high entropy alloy using only tracer diffusion data for a sharp separation of thermodynamic and kinetic data. The established database is valid for the whole composition range of the five-component high entropy alloy.
MOF@MnO2 nanocomposites prepared using in situ method and recyclable cholesterol oxidase–inorganic hybrid nanoflowers for cholesterol determination
Authors: Xu Dawei , Li Cong , Zi Yuqiu , Jiang Dafeng , Qu Fei , Zhao Xian-En 
Published: April 2021

Abstract
In this work, through the in situ growth of MnO2 nanosheets on the surface of terbium metal–organic frameworks (Tb–MOFs), MOF@MnO2 nanocomposites are prepared and the fluorescence of Tb–MOFs is quenched significantly by MnO2. Additionally, the hybrid nanoflowers are self-assembled by cholesterol oxidase (ChOx) and copper phosphate (Cu3(PO4)2·3H2O). Then a new strategy for cholesterol determination is developed based on MOF@MnO2 nanocomposites and hybrid nanoflowers. Cholesterol is oxidized under the catalysis of hybrid nanoflowers to yield H2O2, which further reduces MnO2 nanosheets into Mn2+. Hence, the fluorescence recovery of Tb–MOFs is positively correlated to the concentration of cholesterol in the range of 10 to 360 μM. The limit of detection (LOD) of cholesterol is 1.57 μM. On the other hand, the hierarchical and confined structure of ChOx–inorganic hybrid nanoflowers greatly improve the stability of the enzyme. The activity of hybrid nanoflowers remains at a high level for one week when stored at room temperature. Moreover, the hybrid nanoflowers can be collected by centrifugation and reused. The activity of hybrid nanoflowers can continue at a high level for five cycles of determination. Therefore, it can be concluded that the hybrid nanoflowers are more stable and more economic than free enzymes, and they show a similar sensitivity and specificity to cholesterol compared with free ChOx. Finally, this strategy has been further validated for the determination of cholesterol in serum samples with satisfactory recoveries.
Generalized collisional fluid theory for multi-component, multi-temperature plasma using the linearized Boltzmann collision operator for scrape-off layer/edge applications
Authors: Raghunathan M , Marandet Y , Bufferand H , Ciraolo G , Ghendrih Ph , Tamain P , Serre E 
Published: April 2021

Abstract
Grad’s method is used on the linearized Boltzmann collision operator to derive the most general expressions for the collision coefficients for a multi-component, multi-temperature plasma up to rank-2. In doing so, the collision coefficients then get expressed as series sum of pure coefficients of temperature and mass ratios multiplied by the cross-section dependent Chapman–Cowling integrals. These collisional coefficients are compared to previously obtained coefficients by Zhdanov (2002 Transport Processes in Multicomponent Plasma (London: Taylor and Francis)) for 13N-moment multi-temperature scheme. First, the differences in coefficients are compared directly, and then the differences in first approximation to viscosity and friction force are compared. For the 13N-moment multi-temperature coefficients, it is found that they behave reasonably similarly for small temperature differences, but display substantial differences in the coefficients when the temperature differences are high, both for the coefficients and for viscosity and friction force values. Furthermore, the obtained coefficients are compared to the 21N-moment single-temperature approximation provided by Zhdanov et al, and it is seen that the differences are higher than the 13N-moment multi-temperature coefficients, and have substantial differences even in the vicinity of equal temperatures, especially for the viscosity and friction force calculations.
Effects of a coherent mode on the redistribution of divertor particle flux in HL-2A H-mode plasmas
Authors: Wu N , Cheng J , Yan L W , Huang Z H , Xu J Q , Wang W C , Ke R , Yang Z C , Ji X Q , Liu L , He X X , Jiang M , Wen J , Miao X G , Zhong W L , Yu L M , Gao J M , Dong Y B , Shi Z B , Liu Y , Yang Q W , Dong J Q , Xu M 
Published: April 2021

Abstract
The effects of a coherent mode (CM) at a frequency of f = 13–16 kHz on the redistribution of divertor particle flux have been studied in HL-2A H-mode plasmas using multiple diagnostics. The experimental results demonstrate that a CM localized at the middle of the pedestal results in outward particle transport, limiting the growth of the pedestal density gradient in the recovery phase of the pedestal, leading to a substantial increase in the localized particle flux striking the outer divertor target, which clearly deviates from the primary peak at the strike point. These observations indicate that the CM might play a crucial role in redistributing the divertor particle flux, which is important for understanding and controlling the divertor heat flux in future fusion-relevant devices.
The Cosmological Optical Theorem
Authors: Goodhew Harry , Jazayeri Sadra , Pajer Enrico 
Published: April 2021

Abstract
The unitarity of time evolution, or colloquially the conservation of probability, sits at the heart of our descriptions of fundamental interactions via quantum field theory. The implications of unitarity for scattering amplitudes are well understood, for example through the optical theorem and cutting rules. In contrast, the implications for in-in correlators in curved spacetime and the associated wavefunction of the universe, which are measured by cosmological surveys, are much less transparent. For fields of any mass in de Sitter spacetime with a Bunch-Davies vacuum and general local interactions, which need not be invariant under de Sitter isometries, we show that unitarity implies an infinite set of relations among the coefficients ψ
n
of the wavefunction of the universe with n fields, which we name Cosmological Optical Theorem. For contact diagrams, our result dictates the analytic structure of ψ
n
and strongly constrains its form. For example, any correlator with an odd number of conformally-coupled scalar fields and any number of massless scalar fields must vanish. For four-point exchange diagrams, the Cosmological Optical Theorem yields a simple and powerful relation between ψ3 and ψ4, or equivalently between the bispectrum and trispectrum. As explicit checks of this relation, we discuss the trispectrum in single-field inflation from graviton exchange and self-interactions. Moreover, we provide a detailed derivation of the relation between the total-energy pole of cosmological correlators and flat-space amplitudes. We provide analogous formulae for sub-diagram singularities. Our results constitute a new, powerful tool to bootstrap cosmological correlators.
Unsupervised machine learning can delineate central sulcus by using the spatiotemporal characteristic of somatosensory evoked potentials
Authors: Asman Priscella , Prabhu Sujit , Bastos Dhiego , Tummala Sudhakar , Bhavsar Shreyas , McHugh Thomas Michael , Ince Nuri Firat 
Published: April 2021

Abstract

Objective. Somatosensory evoked potentials (SSEPs) recorded with electrocorticography (ECoG) for central sulcus (CS) identification is a widely accepted procedure in routine intraoperative neurophysiological monitoring. Clinical practices test the short-latency SSEPs for the phase reversal over strip electrodes. However, assessments based on waveform morphology are susceptible to variations in interpretations due to the hand area’s localized nature and usually require multiple electrode placements or electrode relocation. We investigated the feasibility of unsupervised delineation of the CS by using the spatiotemporal patterns of the SSEP captured with the ECoG grid. Approach. Intraoperatively, SSEPs were recorded from eight patients using ECoG grids placed over the sensorimotor cortex. Neurosurgeons blinded to the electrophysiology identified the sensory and motor gyri using neuronavigation based on sulcal anatomy. We quantified the most discriminatory time points in SSEPs temporal profile between the primary motor (M1) and somatosensory (S1) cortex using the Fisher discrimination criterion. We visualized the amplitude gradient of the SSEP over a 2D heat map to provide visual feedback for the delineation of the CS based on electrophysiology. Subsequently, we employed spectral clustering using the entire the SSEP waveform without selecting any time points and grouped ECoG channels in an unsupervised fashion. Main results. Consistently in all patients, two different time points provided almost equal discrimination between anterior and posterior channels, which vividly outlined the CS when we viewed the SSEP amplitude distribution as a spatial 2D heat map. The first discriminative time point was in proximity to the conventionally favored ∼20 ms peak (N20), and the second time point was slightly later than the markedly high ∼30 ms peak (P30). Still, the location of these time points varied noticeably across subjects. Unsupervised clustering approach separated the anterior and posterior channels with an accuracy of 96.3% based on the time derivative of the SSEP trace without the need for a subject-specific time point selection. In contrast, the raw trace resulted in an accuracy of 88.0%. Significance. We show that the unsupervised clustering of the SSEP trace assessed with subdural electrode grids can delineate the CS automatically with high precision, and the constructed heat maps can localize the motor cortex. We anticipate that the spatiotemporal patterns of SSEP fused with machine learning can serve as a useful tool to assist in surgical planning.
A novel Boundary Element model for solving stationary inhomogeneous heat conduction problems
Authors: Barcelos H M , Loeffler C F , Lara L O C 
Published: April 2021

Abstract
A new formulation of BEM applied to steady heat conduction problems, governed by the inhomogeneous Laplace Equation will be presented. The thermal property is isotropic, but varies according to a function known throughout the domain. DIBEM and DST are used together to generate the numerical model. Being used in the interpolation process, two distinct RBF will be used to evaluate the formulation performance. In order to show the generality and capacity of the proposed model, the heat flux variation in a machine tool temperature sensor is calculated. The comparison of the quality of the results achieved is made using FEM.
Correlating ultrasonic pulse velocity and compression resistance of dry concretes at 54 kHz and 500 kHz
Authors: Santos E W J , Pinto E S F , Santos F D G , Dourado T C , Costa-Félix R P B 
Published: April 2021

Abstract
Nondestructive tests applying ultrasound in concrete is used for more than halfcentury. However, the difficulties in making transit time measurement in heterogeneous media have limited the spread use of these applications. The objective of this work is to present a metrological protocol to determine the correlation between the compressive strength of concrete specimens with about 1 year of cure with their respective longitudinal ultrasonic pulse velocity (UPV). From excitation signals sent through a tunable square wave using the direct transmission method, two pairs of transducers with central frequencies of 54 kHz and 500 kHz were used. UPV is determined by the relation between the length and the propagation time of flight the waveform travels within the concrete test specimens. The pieces were constructed according to ABNT NBR 5738:2015 (Concrete – Procedure for molding and curing of concrete specimens) and tested for compression according to ABNT NBR 5739:2007 (Cylindrical specimen compression test – Method of the test). The preliminary results obtained discloses a coherent increase in UPV and concrete strength. Moreover, the highest frequency leads to higher UPV. With the findings presented in this paper, it is possible to define a dual-frequency nondestructive ultrasound method to evaluate concrete resistance more reliable than the traditional approach.
Determining the LOD and LOQ in steel alloys analysis using NITON spectrometer
Authors: Krummenauer A , Dias P R , Veit H M 
Published: April 2021

Abstract
Low concentrations standards spectrometric analysis using the NITON spectrometer require the LOD and LOQ to be determined from the analytical method along with identification of the sample matrix. The LOD (the smallest quantity of analyte that can be detected but not necessarily quantified) and LOQ (the smallest quantity of analyte that can be measured with acceptable accuracy) must be determined for each individual matrix because the energy dispersive X-ray fluorescence (EDXRF) method used by NITON spectrometer is strongly influenced by the matrix effect. This study determined LODs and LOQs for steel alloy samples using certified reference materials with low analyte concentration and compared the calculated LODs and LOQs to those specified by the manufacturer using a two-way ANOVA analysis for each chemical element.
Ensuring the validity of results of hydrophone calibration by a mutual comparison calibration method
Authors: Oliveira E G , Alvarenga A V , Costa-Felix R P B 
Published: April 2021

Abstract
Hydrophone calibration is one of the most important basic metrology activities in ultrasound. Hydrophones are used in many different calibrations and testing methods in industry, for instance, the evaluation of medical electrical equipment basic safety and essential performance. Ensuring the validity of results of metrological services is a major concern for any laboratory. Primary calibration of measuring instrument or standard is a widely understood way to assure good results, despite it is not enough, it is not the unique way, neither it is easy to get in some circumstances. For instance, hydrophone calibration is a service restricted to a few laboratories worldwide, which demands a logistic effort and may be quite expensive. An alternative method to guarantee the traceability by in-house check is of interest. This paper presents a method to ensure the traceability of hydrophones after mutual calibrations. Eight previously calibrated hydrophones from different manufactures and characteristics (membrane and needle) were mutually calibrated, by comparison, all of them acting as standards and calibration items. Calibrations were performed from 1 MHz to 10 MHz and the results were evaluated by pair-difference chi-squared statistics. Uncertainties typically laid between 6% to 13% and sensitivities were between 33 to 318 nV Pa−1. After statistics analyses, 4 hydrophones were considered reliable to be used as standards, as their sensitivity keep on stable even after several years since the last calibration. The method can be used by the industry, accredited laboratories, or national metrology institutes to perform functional checks for virtually any measuring instrument or standard, being the limit the number of available devices to properly apply the statistical analysis.
Evaluation of measurement uncertainty of speed of sound in soybean oil
Authors: Oliveira P A , Baesso R M , Alvarenga A V , Costa-Félix R P B 
Published: April 2021

Abstract
Ultrasound can be used to measure several physical and acoustic properties of oils and fuels. However, most studies do not introduce an assessment of measurement uncertainty. It is well known that uncertainty assessment is important to ensure the quality of measurement results. This work presents the evaluation of the factors that influence the measurement uncertainty of the speed of sound in soybean oil. A detailed uncertainty budget of measurement was shown. The speed of sound in soybean oil was measured by the pulse-echo technique (@ 1 MHz), and the result was 1483.4 m·s−1 ± 2.8 m·s−1 (k = 1.96; p = 0.95).
Monitoring and evaluation of relationship marketing initiatives in service companies: proposition of a multicriteria model for selecting indicators and metrics
Authors: Meneses Cristiana Valente , Almeida Maria Fatima Ludovico de 
Published: April 2021

Abstract
With an attempting to fill the research gap concerning common metrics for advancing research in the field of relationship marketing, this paper aims to propose a conceptual model for monitoring and evaluating relationship marketing initiatives carried out by service companies, with the support of a hybrid multicriteria decision-making method. To demonstrate the applicability of this conceptual model in the context of a service company in Brazil, an empirical study focusing on a relationship marketing initiative of Light SESA was developed during the applied phase of the research. As main results, we can highlight the tool for selecting and hierarchizing indicators and respective metrics; and a consistent set of indicators, aiming at the continuous improvement of RM initiatives in service companies.
Understanding the Radiation Thermometers
Authors: Sohn R S T M 
Published: April 2021

Abstract
Radiation thermometers use the laws of thermal radiation to compute the temperature as a function of the measured spectral radiance. The more precise calculations involve the integration of Planck’s Law, which turns the mathematical developments more complex. In this article, whenever possible we use the concept of monochromatic radiation thermometers, which has the advantage of facilitating mathematical developments and allowing the reader to obtain more easily an overview of the instrument behaviour. In addition, we deal with three important types of thermometers: total radiation, spectral band, and ratio thermometers. Some concepts such as radiance and exitance were also presented.
Development and validation of ICP OES methodologies for the determination of metals in powder milk for in proficiency test applications
Authors: Câmara V , Araújo T , Caciano de Sena R , Osorio A , Almeida M 
Published: April 2021

Abstract
The main purpose of this work was the development and validation of methods for measuring the macro and microelements (Ca, Na, Mg, P, Fe, and Zn) in powder milk by inductively coupled plasma optical emission spectrometry (ICP OES). The validated methods were applied for measuring these elements in commercial samples in order to choose a suitable mix sample to prepare a reference material batch and use it for organizing a proficiency test. This comparison will be used to evaluate the performance of national laboratories for measuring the mass fraction of essential elements in powder milk. Samples were digested in a microwave reaction system and the elements were measured using the external calibration approach. The standard uncertainty for the mass fractions of Mg, P, Fe and Zn ranged from 1.2% to 2.8%. The method accuracy was evaluated using certified reference material (SRM 1849a) from the National Institute of Standards and Technology (NIST). The results obtained from the SRM 1849a and the measured values with the proposed methodologies was checked, and the results obtained for Mg, P, Fe, and Zn were considered consistent with the certified values, but not for Ca and Na. In this case, we need to perform additional studies in order to reevaluate these last two methods. After we checked the performance of methods, five commercial samples were chosen to determine the mass fraction of Mg, P, Fe, and Zn. Among these samples, in only one all elements were present at a suitable mass fraction for organizing a proficiency test.