bluuebunny/crossref_metadata_2025_split huggingface dataset:
Multi-scale dilated dense reconstruction network for limited-angle computed tomography
Authors: Zhou Haichuan , Zhu Yining , Zhang Huitao , Zhao Xing , Zhang Peng 
Published: February 2023

Abstract

Objective. Due to the incomplete projection data, the image reconstructed by limited-angle computed tomography (CT) usually suffers from significant artifacts, by which the structural details are heavily blurred. In this study, we aim to develop a novel approach to improve the limited-angle CT reconstruction performance, especially for the narrow scanning angular range. Approach. A deep learning based iterative framework for limited-angle tomography is proposed, which is named multi-scale dilated dense reconstruction network (MSDDRNet). The MSDDRNet utilizes a multi-scale dilated dense convolution neural network (MSDD-CNN) with conventional reconstruction algorithm for predicting image from incomplete projection data. The MSDD-CNN enhances the image features in the network by merging the DenseNet-Like structure, which serves to restore invisible singularities and reduce artifacts, as well as introducing constraints on the projection domain data into the iterative process to achieve better image detail recovery. Additionally, to improve the training speed of the network, we use a strategy of pre-training and model migration. Main results. Numerical experiments demonstrate that the proposed MSDDRNet performs well in terms of artifact correction, noise reduction and structure recovery compared to existing methods with limited scan angles, and we also extend the proposed method to more general scanning condition and other application such as dental CT data. Significance. The proposed method is a general framework, which can be applied to other CT problems, such as low dose CT, sparse-data CT and spectral CT.
Quantitative photoacoustic tomography with light fluence compensation based on radiance Monte Carlo model
Authors: Zheng Sun , Yingsa Hou , Meichen Sun , Qi Meng 
Published: February 2023

Abstract

Objective. Photoacoustic tomography (PAT) is a rapidly evolving imaging modality that provides images with high contrast and spatial resolution showing the optical properties of biological tissues. The photoacoustic pressure is proportional to the product of the optical absorption coefficient and the local light fluence. The essential challenge in reconstructing quantitative images representing spatially varying absorption coefficients is the unknown light fluence. In addition, optical attenuation induces spatial variations in the light fluence, and the heterogeneity of the fluence determines the limits of reconstruction quality and depth. Approach. In this work, a reconstruction enhancement scheme is proposed to compensate for the variation in the light fluence in the absorption coefficient recovery. The inverse problem of the radiance Monte Carlo model describing light transport through the tissue is solved by using an alternating optimization strategy. In the iteration, the absorption coefficients and photon weights are alternately updated. Main results. The method provides highly accurate quantitative images of absorption coefficients in simulations, phantoms, and in vivo studies. The results show that the method has great potential for improving the accuracy of absorption coefficient recovery compared to conventional reconstruction methods that ignore light fluence variations. Comparison with state-of-the-art fluence compensation methods shows significant improvements in root mean square error, normalized mean square absolute distance, and structural similarity metrics. Significance. This method achieves high precision quantitative imaging by compensating for nonuniform light fluence without increasing the complexity and operation of the imaging system.
Coupled simulations with SOLPS-ITER and B2.5-Eunomia for detachment experiments in Magnum-PSI
Authors: Gonzalez J , Chandra R , de Blank H J , Westerhof E 
Published: February 2023

Abstract
Heat loads of 10 MW m−2 are expected for steady state operation at ITER and up to 20 MW m−2 in slow transient situations. Plasma linear devices like Magnum-PSI can recreate situations close as those expected to be achieved at ITER divertor, providing easier access for diagnostics than in a tokamak. Numerical models are still necessary to complement experiments and to extrapolate relevant information to fusion devices, as the relevant atomic and molecular processes. SOLPS-ITER (formerly known as B2.5-Eirene) is typically employed to solve the plasma and neutral distribution in a coupled way for tokamak devices. For Magnum-PSI, B2.5 has been coupled with a different neutral module, named Eunomia, developed mostly for linear devices. Nevertheless, there is an interest in using SOLPS-ITER for simulating Magnum-PSI, as it would ease the process of relating linear device results with tokamaks. A previous work found significant differences in the implementation of relevant plasma-neutral processes in Eirene and Eunomia. A wide range of plasma scenarios are compared between B2.5-Eunomia and SOLPS-ITER. Although both codes produce results close to experimental Thomson scattering density and temperature near the target once the electric potential at the source is adjusted, these are achieved with completely different plasma and neutral distributions. Anomalous transport coefficients, which are other of the free-parameters in Magnum-PSI simulation, are set equal between the two codes. When studied in a wide range of neutral pressures, SOLPS-ITER shows a trend closer to experiments, as well as providing a converged solution at neutral pressures higher than 4 Pa for which B2.5-Eunomia was unable to provide a converged solution. Additional measurements of the neutral distribution in the target chamber as well as the electric potential at the source are required to determine which code is producing results closer to the experiment.
Global linear stability analysis of kinetic trapped ion mode (TIM) in tokamak plasma using the spectral method
Authors: Mandal D , Lesur M , Gravier E , Sama J N , Guillevic A , Sarazin Y , Garbet X 
Published: February 2023

Abstract
Trapped ion modes (TIMs) belong to the family of ion temperature gradient (ITG) modes, which are one of the important ingredients in heat turbulent transport at the ion scale in tokamak plasmas. A global linear analysis of a reduced gyro-bounce kinetic model for trapped particle modes is performed, and a spectral method is proposed to solve the dispersion relation. Importantly, the radial profile of the particle drift velocity is taken into account in the linear analysis by considering the magnetic flux ψ dependency of the equilibrium Hamiltonian

H

e
q

(
ψ
)

in both the quasi-neutrality equation and equilibrium gyro-bounce averaged distribution function

F

e
q

. Using this spectral method, linear growth rates of TIM instability in the presence of different temperature profiles and precession frequencies of trapped ions, with an approximated constant Hamiltonian and the exact ψ dependent equilibrium Hamiltonian, are investigated. The growth rate depends on the logarithmic gradient of temperature κ

T
, density κ

n
and equilibrium Hamiltonian

κ

Λ

. With the exact ψ dependent Hamiltonian, the growth rates and potential profiles are modified significantly, compared to the cases with an approximated constant Hamiltonian. All the results from the global linear analysis agree with a semi-Lagrangian based linear Vlasov solver with good accuracy. This spectral method is very fast and requires much less computation resources compared to a linear version of the Vlasov-solver based on a semi-Lagrangian scheme.
Structural design and experimental study of multi-ring and multi-disc magnetorheological valve
Authors: Yang Xiaolong , Cao Zhiqiang , Liu Gang , Xie Guojin 
Published: February 2023

Abstract
In order to solve the problems of small pressure drop range and achieve lower response time and small power consumption of traditional control valves in automotive hydraulic lift, the magnetic circuit method was employed to design a new multi-ring and multi-disc magnetorheological valve based on magnetorheological fluid and its pressure drop mathematical model was established. Through the electromagnetic field simulation, the effect of current size, radial damping gap size, axial damping gap size and magnetic isolation thickness affect the performance of the multi-ring and multi-disc magnetorheological valve is studied. The pressure drop characteristics and response time of the multi-ring and multi-disc MR valve under different currents, different direction of loading current and different loads have been studied experimentally. The results show that the saturation pressure drop of the multi-ring and multi-disc MR valve is greater than 7 MPa, and the response time is 136 ms–178 ms, which proves the performance advantage of the multi-ring and multi-disc MR valve.
Astrophysical observations of a dark matter-Baryon fifth force
Authors: Gresham Moira I. , Lee Vincent S.H. , Zurek Kathryn M. 
Published: February 2023

Abstract
We consider the effects of an attractive, long-range Yukawa interaction between baryons and dark matter (DM), focusing in particular on temperature and pulsar timing observations of neutron stars (NSs). We show that such a fifth force, with strength modestly stronger than gravity at ranges greater than tens of kilometers (corresponding to mediator masses less than 10-11eV), can dramatically enhance dark matter kinetic heating, capture, and pulsar timing Doppler shifts relative to gravity plus short range interactions alone. Using the coldest observed NS and pulsar timing array (PTA) data, we derive limits on fifth force strength over a DM mass range spanning light dark matter up to order solar mass composite DM objects. We also consider an indirect limit by combining bullet cluster limits on the DM self-interaction with weak equivalence principle test limits on baryonic self-interactions. We find the combined indirect limits are moderately stronger than kinetic heating and PTA limits, except when considering a DM subcomponent.
Laser cladding of IN713 LC superalloy with Amdry 997 powder: microstructural evolution
Authors: Khorram Ali 
Published: February 2023

Abstract
In this research, Amdry 997 powder was applied by a laser cladding process to the IN713 Low Carbon (IN713 LC) nickel-based superalloy. To evaluate the microstructural behaviors of the clad zones, different variables (the laser speed, laser frequency, and pulse width) were used in the laser cladding process. The final aim of this study was to achieve a clad zone without obvious cracks and pores with a low dilution ratio. The results showed that the upper region of the cladding includes very small equiaxed dendrites. The middle region of the cladding includes columnar dendrites. Equiaxed and columnar grains can be formed at the interface region. With an increase in the heat input of the laser (increasing the pulse width and laser frequency or decreasing the laser speed), the solidification rate reduces and consequently, a longer solidification time exists. Hence, more elongated grains are formed at the interface region. The microstructure of coatings in the upper and middle regions includes γ-Ni, β-NiAl and γ′-Ni3Al phases and TaC carbide, whereas the microstructure of the coatings at the interface region includes γ and β-NiAl and γ′-Ni3Al phases and M (Mo, Ta)C carbide. The optimum laser parameters that result in a low dilution ratio (14%) and a dense clad zone without obvious crack and porosity are a laser speed of 140 mm min−1,laser frequency of 14 Hz, and pulse width of 9 ms.
Filtering time-dependent covariance matrices using time-independent eigenvalues
Authors: Bongiorno C , Challet D , Loeper G 
Published: February 2023

Abstract
We propose a data-driven, model-free, way to reduce the noise of covariance matrices of time-varying systems. If the true covariance matrix is time-invariant, non-linear shrinkage of the eigenvalues is known to yield the optimal estimator for large matrices. Such a method outputs eigenvalues that are highly dependent on the inputs, as common sense suggests. When the covariance matrix is time-dependent, we show that it is generally better to use the set of eigenvalues that encode the average influence of the future on present eigenvalues resulting in a set of time-independent average eigenvalues. This situation is widespread in nature, one example being financial markets, where non-linear shrinkage remains the gold-standard filtering method. Our approach outperforms non-linear shrinkage both for the Frobenius norm distance, which is the typical loss function used for covariance filtering and for financial portfolio variance minimization, which makes our method generically relevant to many problems of multivariate inference. Further analysis of financial data suggests that the expected overlap between past eigenvectors and future ones is systematically overestimated by methods designed for constant covariances matrices. Our method takes a simple empirical average of the eigenvector overlap matrix, which is enough to outperform non-linear shrinkage.
Single-event effects calibration using two-photon absorption and a CMOS image sensor
Authors: Blommaert D. , Leroux P. , Caestecker A. , Meynants G. 
Published: February 2023

Abstract
This paper proposes a method to get an indication of the amount of electron-hole pairs that are necessary to trigger a single-event effect (SEE) in electronics by using two-photon absorption (TPA) and a CMOS image sensor. One of the most important materials in electronics is silicon, which is also the photosensitive part of CMOS image sensors. TPA can occur in it when two photons with an energy lower than the bandgap energy interact with the same electron within a short time window. This can be done by focusing a pulsed laser beam on a sensitive node in the electronics, generating a cloud of electron-hole pairs and thus simulating a SEE. We propose to first measure the necessary laser energy to generate a SEE with TPA in the electronics, to then focus the laser beam with the same laser energy in the CMOS image sensor. With the CMOS image sensor, we will be able to tell how many electrons were detected, which gives a good indication of how many electron-hole pairs were needed for the SEE. This paper first describes TPA, then characterises different CMOS image sensors to finally compare those results with heavy-ions.
Recent results from DEAP-3600
Authors: Lai M. 
Published: February 2023

Abstract
DEAP-3600 is the largest running dark matter detector filled with liquid argon, set at SNOLAB, in Sudbury, Canada, 2 km underground. The experiment holds the most stringent exclusion limit in argon for WIMPs above 20 GeV/c2. In the most recent published analysis, the background events due to α-induced scintillation in the neck of the detector limited the sensitivity. The sensitivity of the detector in the next WIMP search will be improved thanks to the decrease in backgrounds achieved by hardware upgrades and applying multivariate analyses. Moreover, the WIMP analysis has been revisited in terms of a non-relativistic effective field theory framework, and the impact of possible substructures in the galactic dark matter halo was explored. This analysis was motivated by the latest results from Gaia and the Sloan Sky Digital Survey. Here DEAP-3600 set the world’s best exclusion limit for xenon-phobic dark matter scenarios. Finally, a custom-developed analysis has recently pointed out the extraordinary sensitivity to ultra-heavy, multi-scattering dark matter candidates, resulting in world-leading exclusion limits on two composite dark matter candidates up to Planck scale masses. These proceedings, after a quick overview of the dark matter detection in DEAP-3600, outline the detector upgrades and the dark matter search results from the collaboration of the last three years.
The Bergen proton CT system
Authors: Aehle M. , Alme J. , Barnaföldi G.G. , Bodova T. , Borshchov V. , van den Brink A. , Chaar M. , Eikeland V. , Feofilov G. , Garth C. , Gauger N.R. , Genov G. , Grøttvik O. , Helstrup H. , Igolkin S. , Keidel R. , Kobdaj C. , Kortus T. , Leonhardt V. , Mehendale S. , Mulawade R.N. , Odland O.H. , O’Neill G. , Papp G. , Peitzmann T. , Pettersen H.E.S. , Piersimoni P. , Protsenko M. , Rauch M. , Ur Rehman A. , Richter M. , Röhrich D. , Santana J. , Schilling A. , Seco J. , Songmoolnak A. , Sølie J.R. , Tambave G. , Tymchuk I. , Ullaland K. , Varga-Köfaragó M. , Volz L. , Wagner B. , Wendzel S. , Wiebel A. , Xiao R. , Yang S. , Yokoyama H. , Zillien S. 
Published: February 2023

Abstract
The Bergen proton Computed Tomography (pCT) is a prototype detector under construction. It aims to have the capability to track and measure ions’ energy deposition to minimize uncertainty in proton treatment planning. It is a high granularity digital tracking calorimeter, where the first two layers will act as tracking layers to obtain positional information of the incoming particle. The remainder of the detector will act as a calorimeter. Beam tests have been performed with multiple beams. These tests have shown that the ALPIDE chip sensor can measure the deposited energy, making it possible for the sensors to distinguish between the tracks in the Digital Tracking Calorimeter (DTC).
Effect of valve spacing on peristaltic pumping
Authors: Wolf Ki Tae , Poorghani Amir , Dixon J Brandon , Alexeev Alexander 
Published: February 2023

Abstract
Peristaltic fluid pumping due to a periodically propagating contraction wave in a vessel fitted with one-way elastic valves is investigated numerically. It is concluded that the valve spacing within the vessel relative to the contraction wavelength plays a critical role in providing efficient pumping. When the valve spacing does not match the wavelength, the valves open asynchronously and the volume of the vessel segments bounded by two consecutive valves changes periodically, thereby inducing volumetric fluid pumping. The volumetric pumping leads to higher pumping flowrate and efficiency against an adverse pressure gradient. The optimum pumping occurs when the ratio of valve spacing to contraction wavelength is about

2

/

3

. This pumping regime is characterized by a longer period during which the valves are open. The results are useful for further understanding the pumping features of lymphatic system and provide insight into the design of biomimetic pumping devices.
Contact geometric approach to Glauber dynamics near a cusp and its limitation
Authors: Goto Shin-itiro , Lerer Shai , Polterovich Leonid 
Published: February 2023

Abstract
We study a nonequilibrium mean field Ising model in the low temperature phase regime, where metastable equilibrium states develop a cuspidal (spinodal) singularity. We focus on celebrated Glauber dynamics, and design a contact Hamiltonian flow which captures some of its rough features in this regime. We prove, however, that there is an inevitable discrepancy between the scaling laws for the relaxation time in the Glauber and the contact Hamiltonian dynamical systems.
ZnO nanoparticles-modified polycaprolactone-gelatin membranes for guided/bone tissue regeneration, antibacterial and osteogenic differentiation properties
Authors: Prado-Prone Gina , Silva-Bermudez Phaedra , Rodil Sandra E , Ganjkhani Yasaman , Moradi Ali-Reza , Méndez Franklin J , García-Macedo Jorge A , Bazzar Masoomeh , Almaguer-Flores Argelia 
Published: February 2023

AbstractPeriodontitis is a highly prevalent infectious disease that causes the progressive destruction of the periodontal supporting tissues. If left untreated, it can lead to tooth loss impairing oral function, aesthetics, and the patient’s overall quality of life. Guided and Bone Tissue Regeneration (GTR/BTR) are surgical therapies based on the placement of a membrane that prevents epithelial growth into the defect, allowing the periodontal/bone cells (including stem cells) to regenerate or restore the affected tissues. The success of these therapies is commonly affected by the local bacterial colonization of the membrane area and its fast biodegradation, causing postoperative infections and a premature rupture of the membrane limiting the regeneration process. This study presents the antibacterial and osteogenic differentiation properties of polycaprolactone-gelatin (PCL-G) electrospun membranes modified with ZnO nanoparticles (ZnO-NPs). The membranes´ chemical composition, surface roughness, biodegradation, water wettability, and mechanical properties under simulated physiological conditions, were analyzed by the close relationship with their biological properties. The PCL-G membranes modified with 1, 3, and 6% w/w of ZnO-NPs showed a significant reduction in the planktonic and biofilm formation of four clinically relevant bacteria;A. actinomycetemcomitansserotype b, P. gingivalis,E. coli, andS. epidermidis. Additionally, the membranes presented appropriate mechanical properties and biodegradation rates to be potentially used in clinical treatments. Notably, the membranes modified with the lowest concentration of ZnO-NPs (1% w/w) stimulated the production of osteoblast markers and calcium deposits in human bone marrow-derived mesenchymal stem cells (BM-MSC) and were biocompatible to human osteoblasts cells (hFOB). These results suggest that the PCL-G membranes with 1% w/w of ZnO-NPs are high-potential candidates for GTR/BTR treatments, as they were the most effective in terms of better antibacterial effectiveness at a lower NPs-concentration while creating a favorable cellular microenvironment for bone growth.
Organizing in the “American Congo”: Mississippi’s Freedom Summer and its aftermath
Authors: Holt Thomas C. 
Published: February 2023

Abstract
Following the “March on Washington for Jobs and Freedom” in 1963, the civil rights movement targeted small towns and rural areas of the Deep South, where it discovered that conditions required different tactics than the sit-ins and street marches deployed in New South cities that eventually resulted in the passage of the Civil Rights Act of 1964. For the large black population still residing in the rural Deep South, however, a focus on gaining voting rights was more directly relevant to improving black livelihoods and safety than challenges to discrimination in public accommodations. The power of the ballot in the hands of the black majorities still resident in many plantation counties was a direct threat to continued white political control, however. White populations responded with deadly violence, precipitating a crisis that eventually led to passage of the Voting rights Act of 1965.
African American History: A Very Short Introduction
Authors: Holloway Jonathan Scott 
Published: February 2023

Abstract
What does it mean to be an American? The story of the African American past demonstrates the difficulty in answering this seemingly simple question. If being “American” means living in a land of freedom and opportunity, what are we to make of those Americans who were enslaved and who have suffered from the limitations of second-class citizenship; throughout their lives? African American history illuminates the United States’ core paradoxes, inviting profound questions about what it means to be an American, a citizen, and a human being.This book considers how, for centuries, African Americans have fought for what the black feminist intellectual Anna Julia Cooper called “the cause of freedom.”