bluuebunny/crossref_metadata_2025 huggingface dataset:
Fault severity assessment for rotating machinery via improved Lempel–Ziv complexity based on variable-step multiscale analysis and equiprobable space partitioning
Authors: Su Zhou , Shi Juanjuan , Luo Yang , Shen Changqing , Zhu Zhongkui
Published: February 2022

Fault severity assessment based on vibration measurements for rotating machinery is critical since it can reduce downtime and guarantee the reliability of the equipment. Lempel–Ziv complexity (LZC) has been widely used for the fault severity assessment. However, LZC is of a single-scale analysis and 0-1 encoding, which cannot fully explore the features of vibration signals measured from rotating machinery. This paper, thus, proposes an improved LZC based on the variable-step multiscale analysis (VSMA) and equiprobable space partitioning (ESP) strategies to fully explore features of vibrations of rotating machinery. The VSMA is proposed to overcome the drawback that the single-scale analysis fails to comprehensively uncover features and solve the problem that the traditional multiscale analysis significantly reduces the length of sequences. With the VSMA, a string of time series under different scales can be generated. The ESP is developed to transform the time series into symbolic series, with the capability of reserving the features of vibration signals and being more robust against noise, particularly for non-stationary signals. Then, the ESP based variable-step multiscale LZCs (i.e. ESP-VSMLZCs) are obtained. To fuse the obtained ESP-VSMLZCs and obtain a comprehensive indicator for fault severity assessment, Laplacian score weighting is adopted. As such, a single ESP based variable-step multiscale fusion LZC indicator can be obtained. The proposed indicator is verified by simulated data from a bearing dynamic model and experimental data measured from rotating machinery.
CoFe2O4 nanoparticles dispersed on carbon rods derived from cotton for high-efficiency microwave absorption
Authors: Xu Jiajun , Liu Dong , Meng Yubo , Tang Shiyu , Wang Fei , Bian Chao , Chen Xiaoyue , Xiao Siren , Meng Xiuxia , Yang Naitao
Published: February 2022

Biomass-derived carbon materials have received a surge of scientific attention to develop lightweight and broadband microwave absorbers. Herein, rodlike porous carbon materials derived from cotton have been fabricated with uniformly dispersed CoFe2O4 nanoparticles via facile and scalable process. The combination of magnetic particles and carbonaceous material is advantageous to realize the magnetic-dielectric synergistic effect which could effectively promote the dissipation of incident waves, giving rise to an optimal reflection loss value of –48.2 dB over a qualified bandwidth (4.8 GHz) at 2.5 mm. The cotton-derived carbon rods with conductive network not only act as a supporter to carry the CoFe2O4 nanoparticles, but also provide massive heterointerfaces to facilitate the interfacial polarization. In consideration of the renewable and abundant resource of cotton, the as-prepared CoFe2O4/C composites would meet the increasing demand of lightweight and highly efficient microwave absorbers.
Electrostatic shock waves driven by electron vortices in laser–plasma interactions
Authors: Yue D N , Chen M , Geng P F , Yuan X H , Dong Q L , Sheng Z M , Zhang J
Published: February 2022

Nonlinear structures such as shock waves and vortices widely exist in nature and the Universe. They have also been separately observed in laser–plasma interactions. We show for the first time that two perpendicularly propagated collisionless electrostatic shock waves (CESs) can be excited by a moving electron vortex (EV). The latter is driven by an ultrashort intense laser pulse propagating through a sandwich nonuniform underdense plasma slab and is found to move perpendicularly to the density gradient. Two CESs are observed on both sides of the passing route of the EVs. The left-side CES is induced by a high-density electron layer, which originates from the vortex front and is compressed and accelerated during the EV motion. The right-side CES is induced by supersonic ions accelerated by the EVs directly. Ion acceleration by such CESs along the directions perpendicular to the vortex propagation is also observed. This study reveals the transformation of nonlinear structures and provides new routes for laser energy dissipation in plasmas.
The scientific potential and technological challenges of the High-Luminosity Large Hadron Collider program
Authors: Brüning Oliver , Gray Heather , Klein Katja , Lamont Mike , Narain Meenakshi , Polifka Richard , Rossi Lucio
Published: February 2022

We present an overview of the High-Luminosity (HL-LHC) program at the Large Hadron Collider (LHC), its scientific potential and technological challenges for both the accelerator and detectors. The HL-LHC program is expected to start circa 2027 and aims to increase the integrated luminosity delivered by the LHC by an order of magnitude at the collision energy of 14 TeV. This requires upgrades to the injector system, accelerator complex and luminosity levelling. The two experiments, ATLAS and CMS, require substantial upgrades to most of their systems in order to cope with the increased interaction rate, and much higher radiation levels than at the current LHC. We present selected examples based on novel ideas and technologies for applications at a hadron collider. Both experiments will replace their tracking systems. We describe the ATLAS pixel detector upgrade featuring novel tilted modules, and the CMS Outer Tracker upgrade with a new module design enabling use of tracks in the level-1 trigger system. CMS will also install state-of-the-art highly segmented calorimeter endcaps. Finally, we describe new picosecond precision timing detectors of both experiments. In addition, we discuss how the upgrades will enhance the physics performance of the experiments, and solve the computing challenges posed by the expected large data sets. The physics program of the HL-LHC is focused on precision measurements probing the limits of the Standard Model (SM) of particle physics and discovering new physics. We present a selection of studies that have been carried out to motivate the HL-LHC program. A central topic of exploration will be the characterization of the Higgs boson. The large HL-LHC data samples will extend the sensitivity of searches for new particles or new interactions whose existence has been hypothesized in order to explain shortcomings of the SM. Finally, we comment on the nature of large scientific collaborations.
Pulsed multireservoir engineering for a trapped ion with applications to state synthesis and quantum Otto cycles
Authors: Teixeira W S , Keller M K , Semião F L
Published: February 2022

Conducting an open quantum system towards a desired steady state through reservoir engineering is a remarkable task that takes dissipation and decoherence as tools rather than impediments. Here we develop a collisional model to implement reservoir engineering for the one-dimensional harmonic motion of a trapped ion. Our scheme is based on the pulsed interaction between the vibrational mode and the electronic levels of a trapped ion, which is promoted by resolved-sideband lasers. Having multiple internal levels, we show that multiple reservoirs can be engineered, allowing for more efficient synthesis of well-known non-classical states of motion and the generation of states that are unfeasible with a single-bath setup, for instance, thermal states with arbitrary positive temperatures. We apply these ideas to quantum Otto cycles beyond purely thermal reservoirs. In particular, we present general conditions for the violation of the standard Otto bound in the limiting regime of non-adiabatic dynamics.
Nonlinear Maxwell equations and strong-field electrodynamics
Authors: Bruce S A
Published: February 2022

We investigate two Lagrangian models of nonlinear electrodynamics (NLED). These models lead to two different sets of nonlinear (NL) Maxwell equations. The first case deals with the well-known Heisenberg-Euler (HE) model of electromagnetic (EM) self-interactions in a vacuum where only the lowest orders in EM Lorentz invariants are considered. The second instance proposes an extension of the HE model. It consists of a NL Maxwell-Dirac spinor model where the EM field modifies the dynamics of the energy-momentum operator sector of the Dirac Lagrangian instead of its rest-mass term counterpart. This work complements our recent research on NL Dirac equations in the strong EM field regime.
Predicting outcomes of electric dipole and magnetic moment experiments
Authors: Baryshevsky V G , Porshnev P I
Published: February 2022

The anomalous magnetic and electric dipole moments in spin motion equation acquire pseudoscalar corrections if the T(CP)-noninvariance is admitted. It allows to explain the discrepancy between experimental and theoretical values of muon g–2 factor under assumption that the pseudoscalar correction is the dominant source of this discrepancy.
Primordial tensor bispectra in μ-CMB cross-correlations
Authors: Orlando Giorgio , Meerburg P. Daniel , Patil Subodh P.
Published: February 2022

Cross-correlations between Cosmic Microwave Background (CMB) temperature and polarization anisotropies and μ-spectral distortions have been considered to measure (squeezed) primordial scalar bispectra in a range of scales inaccessible to primary CMB bispectra. In this work we address whether it is possible to constrain tensor non-Gaussianities with these cross-correlations. We find that only primordial tensor bispectra with statistical anisotropies leave distinct signatures, while isotropic tensor bispectra leave either vanishing or highly suppressed signatures. We discuss how the angular dependence of squeezed bispectra in terms of the short and long momenta determine the non-zero cross-correlations. We also discuss how these non-vanishing configurations are affected by the way in which primordial bispectra transform under parity. By employing the so-called BipoSH formalism to capture the observational effects of statistical anisotropies, we make Fisher-forecasts to assess the detection prospects from μ T, μ E and μ B cross-correlations. Observing statistical anisotropies in squeezed ⟨γγγ⟩ and ⟨γγζ⟩ bispectra is going to be challenging as the imprint of tensor perturbations on μ-distortions is subdominant to scalar perturbations, therefore requiring a large, independent amplification of the effect of tensor perturbations in the μ-epoch. In absence of such a mechanism, statistical anisotropies in squeezed ⟨ζζγ⟩ bispectrum are the most relevant sources of μ T, μ E and μ B cross-correlations. In particular, we point out that in anisotropic inflationary models where ⟨ζζζ⟩ leaves potentially observable signatures in μ T and μ E, the detection prospects of ⟨ζζγ⟩ from μ B are enhanced.
Schizophrenia induces abnormal frequency-dependent patterns of dynamic brain network reconfiguration during an auditory oddball task
Authors: Núñez Pablo , Gómez Carlos , Rodríguez-González Víctor , Hillebrand Arjan , Tewarie Prejaas , Gomez-Pilar Javier , Molina Vicente , Hornero Roberto , Poza Jesús
Published: February 2022

Objective. Schizophrenia is a psychiatric disorder that has been shown to disturb the dynamic top-down processing of sensory information. Various imaging techniques have revealed abnormalities in brain activity associated with this disorder, both locally and between cerebral regions. However, there is increasing interest in investigating dynamic network response to novel and relevant events at the network level during an attention-demanding task with high-temporal-resolution techniques. The aim of the work was: (i) to test the capacity of a novel algorithm to detect recurrent brain meta-states from auditory oddball task recordings; and (ii) to evaluate how the dynamic activation and behavior of the aforementioned meta-states were altered in schizophrenia, since it has been shown to impair top-down processing of sensory information. Approach. A novel unsupervised method for the detection of brain meta-states based on recurrence plots and community detection algorithms, previously tested on resting-state data, was used on auditory oddball task recordings. Brain meta-states and several properties related to their activation during target trials in the task were extracted from electroencephalography data from patients with schizophrenia and cognitively healthy controls. Main results. The methodology successfully detected meta-states during an auditory oddball task, and they appeared to show both frequency-dependent time-locked and non-time-locked activity with respect to the stimulus onset. Moreover, patients with schizophrenia displayed higher network diversity, and showed more sluggish meta-state transitions, reflected in increased dwell times, less complex meta-state sequences, decreased meta-state space speed, and abnormal ratio of negative meta-state correlations. Significance. Abnormal cognition in schizophrenia is also reflected in decreased brain flexibility at the dynamic network level, which may hamper top-down processing, possibly indicating impaired decision-making linked to dysfunctional predictive coding. Moreover, the results showed the ability of the methodology to find meaningful and task-relevant changes in dynamic connectivity and pathology-related group differences.
Validation of realistic Monte Carlo plasma gamma-ray source on JET discharges
Authors: Žohar A. , Nocente M. , Kos B. , Štancar Ž. , Rebai M. , Rigamonti D. , Craciunescu T. , Gorelenkova M. , Kazakov Ye.O. , Kiptily V.G. , Snoj L. , Tardocchi M. , Lengar I. , JET Contributors
Published: February 2022

A novel modelling methodology has been developed for the creation of a realistic plasma gamma-ray source for Monte Carlo transport simulations in the tokamak JET. The methodology couples the TRANSP code for plasma transport calculations with the MCNP Monte Carlo particle transport code, thus connecting plasma physics with gamma-ray transport. This paper presents the validation of the developed source methodology by comparing calculated gamma-ray spectra with measurements performed at JET. The validation focuses on gamma-ray spectra measured by the tangential gamma-ray spectrometer during two JET three ion RF scenario discharges, performed in the JET 2019 deuterium experimental campaign. For validation the calculated plasma gamma-ray spectrum was combined with the neutron induced prompt gamma-ray background, originating in the vacuum vessel, and scaled to absolute values calculating the total number of plasma gamma-ray and neutron emitting reactions. The comparison between calculated and measured gamma-ray spectra shows good agreement with the shape of the calculated gamma-ray spectra matching that of measurements for both studied discharges. Moreover, the calculated absolute values of the gamma-ray spectra were of the same order of magnitude at the position of the gamma-ray detector located at the end of a long line-of-sight in a biological shield. The comparison has validated the developed plasma gamma-ray source methodology for MCNP photon transport calculations at JET. The validation provides a basis for the developed plasma gamma-ray source to be used as a support for the development of future tokamaks such as DEMO.
Prototype design and performance test of a cosmic ray tracker
Authors: Zhang L. , Dong Y. , Liu Y. , Ma L. , Wu Q. , Yan M. , Peng S. , Qian S. , Wang C. , Wang Z.
Published: February 2022

The High Energy cosmic-Radiation Detection (HERD) facility has been proposed as one of the several space astronomy payloads onboard the future China’s Space Station (CSS), which is planned for operation starting around 2027 for about 10 years. A cosmic ray tracker with position resolution of better than 1 mm and effective detection area of 1 m × 1 m is designed to do detector performance study for sub-detector of the HERD on the ground. The tracker consisits of 1.0 m long scintillating fibers with a diameter of 1 mm which will be arranged in 3 staggered layers. The fibers will be read out by arrays of SiPMs. The performance of a small prototype module is built and tested with radioactive source 90-Sr and cosmic ray. The measured light output of the 3-layer fiber module is larger than 10 photoelectrons per MIP events.
Invisible barcode method base on NDT photoacoustic imaging
Authors: Setiawan A. , Mitrayana
Published: February 2022

The use of barcode technology has spread in many fields
since it is cheaper and easier to use. To date, the barcode
technology is applied by placing a code on a label surface. This
makes access easier but also increases security risks. Security
breaches can occur either due to physical damage to the code or code
hijacking for inappropriate purposes. This paper reports the
development of the subsurface barcode coding method by utilizing
Non-Destructive Testing (NDT) photoacoustic imaging. Referring to
the Rosencwig-Gersho theory, photoacoustics can image the subsurface
conditions by adjusting the thermal conductivity length. In this
experiment, a number of cavities representing barcodes were embedded
in a metal object. The experimental results show that this method
can decode the 3-digit Flattermarken code embedded in a 1 mm thick
metal object again. The success of this new method is expected to
open up more opportunities for barcodes that are more secure and
resistant to tampering.
A simple framework to characterize land aridity based on surface energy partitioning regimes
Authors: He Qing , Lu Hui , Yang Kun , Leung L Ruby , Pan Ming , He Jie , Yao Panpan
Published: February 2022

Land aridity is often characterized by the aridity index (AI), which does not account for land surface water-energy interactions that are crucially important in determining regional climate. Such interactions can be captured by the evaporative fraction (EF, ratio of evapotranspiration to available energy) regimes. As EF is subject to energy and water limitations in humid and dry areas, respectively, EF regimes may be used to characterize land aridity to account for the influence of complex land characteristics and their impact on water availability. Here, we propose a simple framework to characterize land aridity by statistically ranking the coupling strength between EF and surface energy and water terms. The framework is demonstrated using gridded data and compared with AI over the U.S. and China. Results show that regionalization of aridity zones based on EF regimes and a two-tiered classification scheme may provide information such as surface energy and water variability complementary to the background aridity depicted by AI, with implications for extreme events.
Non-linear response of temperature-related mortality risk to global warming in England and Wales
Authors: Huang Wan Ting Katty , Braithwaite Isobel , Charlton-Perez Andrew , Sarran Christophe , Sun Ting
Published: February 2022

Climate change is expected to lead to changes in seasonal temperature-related mortality. However, this impact on health risk does not necessarily scale linearly with increasing temperature. By examining changes in risk relative to degrees of global warming, we show that there is a delayed emergence of the increase in summer mean mortality risk in England and Wales. Due to the relatively mild summer mean temperatures under the current climate and the non-linearity of the exposure–response relationships, minimal changes in summer mean risk are expected at lower levels of warming and an escalation in risk is projected beyond 2.5 °C of global warming relative to pre-industrial levels. In contrast, a 42% increase in mortality risk during summer heat extremes is already expected by 2 °C global warming. Winter attributable mortalities, on the other hand, are projected to decrease largely linearly with global warming in England and Wales.
Social vulnerability in a multi-hazard context: a systematic review
Authors: Drakes Oronde , Tate Eric
Published: February 2022

The interacting effects of multiple hazards pose a substantial challenge to poverty reduction and national development. Yet, social vulnerability to multiple hazards is a relatively understudied, though growing concern. The impacts of climate hazards in particular, leave increasingly large populations becoming more exposed and susceptible to the devastating effects of repeat, chronic and sequential natural hazards. Multi-hazard research has focused on the physical aspects of natural hazards, giving less attention to the social facets of human-hazard interaction. Further, there is no single conceptualization of ‘multi-hazard’. This systematic review utilizes correlations and hierarchical clustering to determine how social vulnerability is assessed in the context of the three most common classifications of ‘multi-hazard’: aggregate, cascading and compound. Results reveal these classifications of ‘multi-hazard’ each focus on different aspects of social vulnerability. Studies in the aggregate classification of multi-hazard were more likely to represent social vulnerability as an outcome of hazard events, while those in the cascading and compound classifications more often addressed social vulnerability as a preexisting condition. Further, knowledge of social vulnerability to multi-hazards comes mainly from the aggregate classification and the mitigation phase of the disaster cycle. The difference in perspectives of social vulnerability covered, and limited context in which multi-hazard studies of social vulnerability have been applied, mean a full understanding of social vulnerability remains elusive. We argue that research should focus on the cascading and compound classifications of multi-hazards, which are more suited to interrogating how human-(multi)hazard interactions shape social vulnerability.
Obtaining the long-term behavior of master equations with finite state space from the structure of the associated state transition network
Authors: Fernengel Bernd , Drossel Barbara
Published: February 2022

The master equation describes the time evolution of the probabilities of a system with a discrete state space. This time evolution approaches for long times a stationary state that will in general depend on the initial probability distribution. Conditions under which the stationary state is unique are usually given as remarks appended to more comprehensive theories in the mathematical literature. We provide a direct and complete derivation of a necessary and sufficient criterion for when this steady state is unique. We translate this problem into the language of graph theory and show that there is a one-to-one correspondence between minimal absorbing sets within the state-transition network and linearly independent stationary states of the master equation.
Experimental investigation of Marble powder mixed micro-electric discharge machining
Authors: Baghel Rupali
Published: February 2022

Micro-electrical discharge machining (EDM) is among the most important machining techniques for creating micro features, notably for cutting challenging materials such as superalloys, ceramics, and composite materials. To improve machining performance characteristics, micro-EDM technology was integrated with the mixing of marble powder in the dielectric fluid in this research. This work investigates the potential of marble powder mixed micro-EDM (PM- EDM) to manufacture high aspect ratio micro holes in a newly designed ceramic, TiN-Al2O3. SEM photos of the action of marble powder on the machined surface are also examined, with thermal cracking (Spalling) and melting being the most prominent mechanisms of material removal.
Simulation and Optimization of an Independent Sustainable Micro Hybrid Electricity System for Rural Consumers
Authors: Kumar Jangid Satish , Asif Iqbal Mohammad , Mishra Rahul
Published: February 2022

A fundamental necessity for sustainable development is to ensure reliable and cost-effective access to modern energy services, primarily for the lower income and impoverished sectors of the population. Successful rural electrification is vital to bridging the rural-urban gap, given that the vast majority of the energy-deprived population resides in rural regions of developing countries. if the existing system of energy services intervened it can influence the development process by livelihood activities, micro or small enterprises, lifestyle energy services, value-added activities, survival irrigation, and so on. Different micro hybrid systems preferably with combination of renewable energy resources will be a good option for addressing given barriers. India has a large Availability of Higher solar radiations, a society that depends on agriculture has enough biomass resources, plentiful cattle dung, forest conifers and agriculture waste. In this paper, we examine the hybrid system’s techno economic feasibility and long-term viability. The system is made up of 60-kW solar photovoltaic panels (PV) and 40-kW biomass gasifier modules. Energy demand and resource availability are measured using data from comprehensive stakeholder discussions and field surveys, and they take into account daily and seasonal fluctuations in supply, end uses, and availability, as well as productive hours. The techno economic viability of electric renewable energy is evaluated using a hybrid optimization model (HOMER). Additionally, prospects for the growth of profitable uses and their extension into a long-term business model are investigated.
Sensing non-ideal microheterogeneity in binary mixtures of dimethyl sulfoxide and water
Authors: Bandyopadhyay Soumendra Nath , Singh Ajitesh , Singh Krishna Kant , Goswami Debabrata
Published: February 2022

We present a microscopic study of water–dimethyl sulfoxide (DMSO) binary mixtures using optical tweezers and thermal lens techniques. Binary mixtures of DMSO with water show anomalous behavior due to the specific hydrogen bonding ability of DMSO. We use a tightly focused femtosecond laser at a low average power to optically trap microspheres with diameters of 1 micron for use as probes. The binary mixture exhibits various viscosities, depending on its composition ratio, and hence different trapped particle characteristic frequencies (corner frequencies) due to Brownian motion. The power spectrum density method is used to obtain the corner frequency from forward-scattered data. Thus, using low-power optical tweezer experiments, we find that the maximum viscosity occurs at a DMSO mole fraction of 0.276. At higher powers, the propensity for trapping is highly diminished. It may be surprising to note that these viscosity values obtained from the corner frequencies do not exactly match those published in the literature. However, this deviation can be attributed to the thermal behavior of the binary mixture, which affects the Brownian motion and hence the obtained viscosity values. Studies at the microscopic level can thus provide a newer perspective on these already important binary mixtures. Intensity-dependent measurements further confirm the contribution of thermal effects in this study.
Two-dimensional Airy waves and three-wave solitons in quadratic media
Authors: Prasatsap Unchittha , Mayteevarunyoo Thawatchai , Malomed Boris A
Published: February 2022

We address the dynamics of two-dimensional (2D) truncated Airy waves (TAWs) and three-component solitons in the system of two fundamental-frequency (FF) and second-harmonic (SH) fields, coupled by quadratic (

χ

(
2
)

) terms. The system models second–harmonic-generating optical media and atomic-molecular mixtures in Bose–Einstein condensates. In addition to stable solitons, the system maintains truncated-Airy-waves states in either one of the FF components, represented by exact solutions, which are stable, unlike the Airy waves in the degenerate (two-component)

χ

(
2
)

system. It is also possible to imprint vorticity onto the 2D Airy modes. By means of systematic simulations, we examine interactions between TAWs originally carried by different FF components, which are bending in opposite directions, through the SH field. The interaction leads to fusion of the input into a pair of narrow solitons. This is opposed to what happens in the 1D system, where the interacting Aity waves split into a large number of solitons. The interaction of truncated Aity waves carrying identical imprinted vorticities creates an additional pair of solitons, while opposite vorticities create a set of small-amplitude ‘debris’ in the output. Slowly moving solitons colliding with a heavy TAW bounce back, faster ones are absorbed by it, and collisions are quasi-elastic for fast solitons. Soliton-soliton collisions lead to merger into a single mode, or elastic passage, for lower and higher velocities, respectively.
Gas permeability measurement in porous graphite under steady-state flow
Authors: Liu Hao , Xu Ying
Published: February 2022

Porous graphite is employed for the development of air bearings used in the ultraprecision machine tools. The static performance of this new bearing type depends on the permeability and inertia coefficient of the porous graphite inserted in it. In this study, an experimental fitting method was used in conjunction with computational fluid dynamics (CFD) modeling to determine the permeability and inertia coefficient of three types of porous graphite with porosity of 16%, 13%, and 8% respectively. The experimental results show that the Compressible-Darcy-Forchheimer equation can fit the experimental mass flow rate and pressure drop well. The average permeability of SG-3, SG-5 and SG-8 porous graphite are

5.74
×

10

−
14

m2,

3.65
×

10

−
15

m2 and

1.85
×

10

−
15

m2 respectively. SG-5 and SG-8 porous graphite have good permeability consistency and can be used to make porous media air bearing. The PPSM (number of pores per square millimeter) of SG-3 and SG-8 are similar, but the permeabilities are very different. For low permeability porous graphite, samples with different sizes from the same material should be tested and the averaged inertia coefficient can be used. The accuracy of the pore-scale FVM (finite volume method) is highly dependent on the quality of the pore microstructure image.
Evaluation of self-healing in concrete with limestone coarse aggregate impregnated with Na2SiO3 solution
Authors: Cruz J C , Hernandez S M , Trejo-Arroyo D L , Zarhri Z , Zárate-Medina J , Jiménez Luis F , Gurrola M P
Published: February 2022

This study investigated the self-healing process in concrete using limestone coarse aggregate impregnated with sodium silicate solution and encapsulated with polyvinyl alcohol (PVA). It discussed the self-healing mechanism by sodium silicate solution and evaluated the effect and the efficiency of this healing agent. To do this, limestone coarse aggregate was vacuum impregnated with a sodium silicate solution, encapsulated with PVA, and mixed into the concrete paste. The compressive strength was improved up to 50% in the concrete samples with sodium silicate. It also evaluated the porosity, density, and absorption ranges. It found a reduction of 4% in the range of absorption. Using x-ray diffraction (XRD), the chemical elements of the healing products were determined and the presence of the crystalline phases Etringite, Calcite, Dolomite and Minrecordite. This agreed with the chemical composition of dolomitic limestone’s (CaMg (CO3)2). The self-healing process was observed in the concrete samples cured at 28 days and was attributed to the formation of calcite crystals and silica gel C-S-H. Using the Scanning Electron Microscopy (SEM), the hydration products like calcite and C-S-H were visualized. Self-healing in the concrete could be observed due to the impregnation of Sodium Silicate in the aggregates.
Towards range-guidance in proton therapy to detect organ motion-induced dose degradations
Authors: Busch Kia , Andersen Andreas Gravgaard , Petersen Jørgen Breede Baltzer , Petersen Stine Elleberg , Rønde Heidi S , Bentzen Lise Nørgaard , Pilskog Sara , Skyt Peter Sandegaard , Nørrevang Ole , Muren Ludvig Paul
Published: February 2022

Introduction: Internal organ motion and deformations may cause dose degradations in proton therapy (PT) that are challenging to resolve using conventional image-guidance strategies. This study aimed to investigate the potential of range guidance using water-equivalent path length (WEPL) calculations to detect dose degradations occurring in PT. Materials and methods: Proton ranges were estimated using WEPL calculations. Field-specific isodose surfaces in the planning CT (pCT), from robustly optimised five-field proton plans (opposing lateral and three posterior/posterior oblique beams) for locally advanced prostate cancer patients, were used as starting points. WEPLs to each point on the field-specific isodoses in the pCT were calculated. The corresponding range for each point was found in the repeat CTs (rCTs). The spatial agreement between the resulting surfaces in the rCTs (hereafter referred to as iso-WEPLs) and the isodoses re-calculated in rCTs was evaluated for different dose levels and Hausdorff thresholds (2-5 mm). Finally, the sensitivity and specificity of detecting target dose degradation (V95%<95%) using spatial agreement measures between the iso-WEPLs and isodoses in the pCT was evaluated. Results: The spatial agreement between the iso-WEPLs and isodoses in the rCTs depended on the Hausdorff threshold. The agreement was 65-88% for a 2 mm threshold, 83-96% for 3 mm, 90-99% for 4 mm, and 94-99% for 5 mm, across all fields and isodose levels. Minor differences were observed between the different isodose levels investigated. Target dose degradations were detected with 82-100% sensitivity and 75-80% specificity using a 2 mm Hausdorff threshold for the lateral fields. Conclusion: Iso-WEPLs were comparable to isodoses re-calculated in the rCTs. The proposed strategy could detect target dose degradations occurring in the rCTs and could be an alternative to a fully-fledged dose re-calculation to detect anatomical variations severely influencing the proton range.
Macroscopic entanglement bags award
Authors: Johnston Hamish
Published: February 2022

The Physics World 2021 Breakthrough of the Year goes to work on the fuzzy interface between the quantum and classical worlds, as Hamish Johnston reports.
Huge haul of fast radio bursts hints at astrophysical origins
Authors: Jarman Sam
Published: February 2022

The greatest number of fast radio bursts (FRBs) ever to be observed from a single source has been reported by an international team of astronomers.
Microscopy technique reveals long-sought ‘sigma-hole’
Authors: Cartlidge Edwin
Published: February 2022

Researchers in the Czech Republic have used Kelvin probe force microscopy to image subatomic structures called “sigma-holes” directly.
Processed wood can be moulded into complex 3D structures
Authors: Jarman Sam
Published: February 2022

Researchers in the US have developed a new technique that allows wood to be shaped into complex 3D structures.
Building bridges between big science and industry
Authors: McEntee Joe
Published: February 2022

Delegates at a recent Big Science Summit in Malmö, Sweden, discussed how best to boost the economic impact of Europe’s research facilities. Joe McEntee reports.
Two-year delay hits major European neutron source
Authors: Banks Michael
Published: February 2022

The €1.8m European Spallation Source will be delayed by two years to 2027 as a result of the COVID-19 pandemic and “technical issues”.
Quantum sensor could detect dementia
Authors: Dumé Isabelle
Published: February 2022

A new quantum sensor could help clinicians identify diseases such as dementia, Alzheimer’s and Parkinson’s by tracking patients’ brain waves.
NASA launches X-ray mission
Authors: Banks Michael
Published: February 2022

NASA has launched a mission to measure the X-ray polarization from objects such as black holes, active galactic nuclei, quasars, pulsars and supernova remnants.
Using physics to COVID-proof everyday life
Authors: Harris Margaret
Published: February 2022

Margaret Harris reports how physicists are using models and experimental techniques to get a better understanding of the transmission of viruses.
What’s in a name?
Authors: Durrani Matin
Published: February 2022

Naming phenomena after discoverers is traditional, but not necessarily permanent.
Contaminating the night sky
Authors: Green Karel
Published: February 2022

Karel Green says that while private space endeavours are to be welcomed, we should not ignore the social and ethical concerns that they raise.
Space for all
Authors: McKenzie James
Published: February 2022

With launch costs plummeting fast, James McKenzie examines the huge commercial potential of the space sector.
Your holiday secrets
Authors: Crease Robert P
Published: February 2022

Robert P Crease reveals readers’ favourite holiday-physics problems – and outlines some new teasers too.
Angels and seed funds
Authors: Scibor-Rylski Mark
Published: February 2022

A response to James McKenzie’s Transactions article “Help me if you can”, which discusses the support that business incubators can offer hi-tech start-ups.
Gone with the wind
Authors: Palmer Tim
Published: February 2022

A response to Amory Lovins’ letter “No new nuclear”, which argues that investment in nuclear energy worsens climate change.
Royle merger
Authors: Charap John
Published: February 2022

A response to the review article “A tale of two scientists”, which discusses the physicist Fred Hoyle’s steady-state cosmological model.
A matter of sound
Authors: Buehler Markus , Milazzo Mario
Published: February 2022

Often called the universal language, music may well represent life itself. Having studied a wide range of biomaterials, from amino-acids and viruses to spider-silk, Markus Buehler and Mario Milazzo explain how they have been able to explore new avenues of research by translating living structures into sound.
Going global: the world the Web has wrought
Authors: Riordan Michael
Published: February 2022

Thirty years after the World Wide Web first expanded from Europe to North America, Michael Riordan reveals how physicists and programmers played important roles in shaping the current wave of globalization.
Ask me anything: Giulia Grancini
Authors: Hiscott Laura
Published: February 2022

Giulia Grancini is a professor of chemistry and an expert in next-generation materials for photovoltaic cells at the University of Pavia.
New year, new physicist
Authors: Hiscott Laura
Published: February 2022

Laura Hiscott wonders whether practising physicists have any habits that they’re keen to kick in the new year.
Liquid metal polymer composites: from printed stretchable circuits to soft actuators
Authors: Majidi Carmel , Alizadeh Kaveh , Ohm Yunsik , Silva Andre , Tavakoli Mahmoud
Published: February 2022

Soft polymers embedded with liquid metals like eutectic gallium-indium (EGaIn) exhibit unique combinations of mechanical, electrical, and thermal properties that are not possible with other material systems. For example, a soft silicone elastomer embedded with a percolating network of EGaIn microdroplets can function as a highly soft and elastic conductor that can be stretched to 600% strain without significant change in electrical resistance. Depending on the choice of polymer matrix and EGaIn microstructure, these soft material composites can be engineered to exhibit mechanical and electrical self-healing properties as well as high fracture toughness and resistance to tearing. Moreover, when solid filler particles like silver flakes are added to EGaIn-polymer composites, they can function as printable conductive inks that are fully elastic, non-marking, and non-smearing when cured. In this short review, we present different classes of EGaIn-polymer composites, discuss approaches to materials synthesis and patterning, and compare their properties with other material systems. Additionally, we will review applications of this emerging class of materials in domains ranging from wearable bioelectronics to soft robotics, shape programmable smart materials, as well as energy storage and harvesting devices.
Two flows Kowalevski top as the full genus two Jacobi’s inversion problem and Sp(4,

R

) lie group structure
Authors: Hayashi Masahito , Shigemoto Kazuyasu , Tsukioka Takuya
Published: February 2022

By using the first and second flows of the Kowalevski top, we can recreate the Kowalevski top into two−flows Kowalevski top, which has two−time variables. Then, we demonstrate that equations of the two−flows Kowalevski top become those of the full genus two Jacobi inversion problem. In addition to the Lax pair for the first flow, we construct a Lax pair for the second flow. Using the first and second flows, we demonstrate that the Lie group structure of these two Lax pairs is Sp(4,

R

)/

Z

2

≅

SO
(
3
,
2
)

. With the two−flows Kowalevski top, we can conclude that the Lie group structure of the genus two hyperelliptic function is Sp(4,

R

)/

Z

2

≅

SO
(
3
,
2
)

.
Examining the changes in the spatial manifestation and the rate of arrival of large tornado outbreaks
Authors: Nouri Niloufar , Devineni Naresh
Published: February 2022

This study presents an assessment of the spatial and temporal characteristics of large tornado outbreak (LTOs) days, in which several counties were impacted by tornadoes rated F2(EF2) or greater on the Fujita (Enhanced Fujita) scale in one day. A statistical evaluation of changes in the LTO clusters for two periods, 1950–1980 and 1989–2019, has been performed. There is a geographical shift of the nucleus (central impact location) towards the southeast United States. This spatial shift is also accompanied by reduced spatial variance, suggesting LTOs have become less dispersed (or more localized) in the recent period. The overall inter-arrival rate of LTOs, and how it changed during successive 31-year climatological blocks between 1950–2019 was investigated using an exponential probability model. The arrival rate has changed from 124 days during 1950–1980 to 164 days during 1977–2007 and remained relatively constant during later periods, indicating that LTOs are becoming less frequent.
Calcium cobaltite, a promising oxide for energy harvesting: effective strategies toward enhanced thermoelectric performance
Authors: Yu Jincheng , Freer Robert
Published: February 2022

Thermoelectric (TE) materials are able to generate power from waste heat and thereby provide an alternative source of sustainable energy. Calcium cobaltite is a promising p-type TE oxide because of its intrinsically low thermal conductivity arising from the misfit-layered structure. Its structural framework contains two sub-layers with different incommensurate periodicities, offering different sites for substituting elements; the plate-like grain structure contributes to texture development, thereby providing opportunities to modulate the TE response. In this topical review, we briefly introduce the misfit crystal structure of calcium cobaltite and summarize three efficient strategies to enhance the TE performance, namely (a) elemental doping, (b) optimization of fabrication route, and (c) composite design. For each strategy, examples are presented and enhancing mechanisms are discussed. The roles of dopants, processing routes and phase composition are identified to provide insights into processing-microstructure-property relationships for calcium cobaltite based materials. We outline some of the challenges that still need to be addressed and hope that the proposed strategies can be exploited in other TE systems.
Optimal insulation thickness of walls using improved Particle swarm optimization
Authors: Chen Xiaofang , Deng Fukang
Published: February 2022

Uninsulated external walls and inappropriate insulation of buildings are the main reason for energy losses. In this study, novel configurations of multi-layer pre-fabricate wall elements were used to enhance the ability of energy-saving and decrease the payback periods and investments in residential houses in five cities in Iran with different energy demands. Also, an optimization strategy is applied to determine optimum insulation thickness for external walls. The evaluation process is based on using natural gas and electricity in Iran’s buildings for heating and cooling, respectively. The optimum required insulation thickness in Cities with different climates according to their degree/day value for four different insulation materials (extruded polystyrene, glass wool, rock wool, and polyurethane) is achieved using a novel optimization method (Improved PSO). According to the obtained results, annual cost saving for

1

m

2

of the wall in case of simultaneous heating & cooling is more than cooling and heating alone. However, for the payback period, simultaneous heating & cooling has a lower payback period than cooling and heating alone. The results revealed that the cost of rock wool is higher, and the cost of polyurethane is higher than the cost of all other insulating materials in Ardabil. Also, the optimal insulation thickness for the Ardabil city with hollow brick walls and heating and cooling needs is

x
=
0.015
m

and

x
=
0.005
m

for the XPS, respectively.
Magnetic field robust high quality factor NbTiN superconducting microwave resonators
Authors: Müller M , Luschmann T , Faltermeier A , Weichselbaumer S , Koch L , Huber G B P , Schumacher H W , Ubbelohde N , Reifert D , Scheller T , Deppe F , Marx A , Filipp S , Althammer M , Gross R , Huebl H
Published: February 2022

We systematically study the performance of compact lumped element planar microwave Nb70Ti30N (NbTiN) resonators operating at 5 GHz in external in-plane magnetic fields up to 440 mT, a broad temperature regime from 2.2 K up to 13 K, as well as mK temperatures. For comparison, the resonators have been fabricated on thermally oxidized and pristine, (001) oriented silicon substrates. When operating the resonators in the multi-photon regime at T = 2.2 K, we find internal quality factors Q
int ≃ 2 × 105 for NbTiN resonators grown on pristine Si substrates. In addition, we investigate the Q-factors of the resonators on pristine Si substrates at millikelvin temperatures to assess their applicability for quantum applications. We find Q
int ≃ 2 × 105 in the single photon regime and Q
int ≃ 5 × 105 in the high power regime at T = 7 mK. From the excellent performance of our resonators over a broad temperature and magnetic field range, we conclude that NbTiN deposited on Si (100) substrates, where the surface oxide has been removed, constitutes a promising material platform for electron spin resonance and ferromagnetic resonance experiments using superconducting planar microwave resonators.
Rigidity properties of the cotangent complex
Authors: Briggs Benjamin , Iyengar Srikanth
Published: February 2022

This work concerns a map

φ
:
R
→
S

\varphi \colon R\to S

of commutative noetherian rings, locally of finite flat dimension. It is proved that the André-Quillen homology functors are rigid, namely, if

D

n

(
S

/

R
;
−
)
=
0

\mathrm {D}_n(S/R;-)=0

for some

n
≥
1

n\ge 1

, then

D

i

(
S

/

R
;
−
)
=
0

\mathrm {D}_i(S/R;-)=0

for all

i
≥
2

i\ge 2

and

φ

{\varphi }

is locally complete intersection. This extends Avramov’s theorem that draws the same conclusion assuming

D

n

(
S

/

R
;
−
)

\mathrm {D}_n(S/R;-)

vanishes for all

n
≫
0

n\gg 0

, confirming a conjecture of Quillen. The rigidity of André-Quillen functors is deduced from a more general result about the higher cotangent modules which answers a question raised by Avramov and Herzog, and subsumes a conjecture of Vasconcelos that was proved recently by the first author. The new insight leading to these results concerns the equivariance of a map from André-Quillen cohomology to Hochschild cohomology defined using the universal Atiyah class of

φ
\varphi

.