bluuebunny/crossref_metadata_2025_split huggingface dataset:
Non‐singular terminal sliding mode control strategy for DC/DC Boost converter system using a finite‐time convergent observer
Authors: Zheng Shicheng , Qi Mengmeng , Shu Ying , Wang Yu , Lang Jiahong 
Published: August 2022

AbstractAiming at such problems as poor dynamic and steady‐state performance, and non‐ideal anti‐interference performance when the traditional sliding mode control is applied in Boost converter, a non‐singular terminal sliding mode control (NTSMC) strategy based on finite time convergence is presented in this paper. Taking the inductor's current and output voltage as the state variables of the system, the average state model of Boost converter under continuous conduction mode (CCM) is established, and the differential equations of the inductor's current and output voltage are obtained. According to the above differential equation, a finite‐time convergent observer (FCO) is designed to estimate the load resistance and input voltage. By combining these estimated values with the NTSMC method, a novel non‐singular terminal sliding surface function and controller are designed, which improves the dynamic, steady‐state performance and anti‐interference performance of the system. The stability of the system is analyzed according to the Lyapunov stability theory. The simulation and experimental results show that, compared with the traditional sliding mode control, the control algorithm proposed in this paper has stronger anti‐interference ability.
Real‐time implementation and evaluation of gorilla troops optimization‐based control strategy for autonomous microgrids
Authors: Maged Nourhan A. , Hasanien Hany M. , Ebrahim Essamudin A. , Tostado‐Véliz Marcos , Jurado Francisco 
Published: August 2022

AbstractThe present work develops a novel gorilla troops optimization algorithm (GTO) for optimal control of an autonomous microgrid. The proposed proportional‐integral controller parameters are properly designed by the GTO algorithm. It is based on the integral squared error to minimize the system objective function. The suggested islanded microgrid system operates with several decentralized, electronically interfaced energy resources and their local loads. The new optimal controller is applied to regulate its voltage at the different points of common coupling and its frequency despite the load variation. The performance of the new proposal is compared with the PI controller that was designed by a particle swarm optimization algorithm. It is observed that the microgrid functioning operation is improved even more by applying a GTO‐based than the other. The control strategy is thoroughly tested using a Matlab/Simulink simpower‐system environment under various microgrid operating situations. It is also implemented with OPAL 4510 real‐time hardware in the loop and a rapid control prototyping module. The different benchmark experiments serve to show the superiority of the new optimizer.
Versatile static synchronous machine and its reference machine following control strategy
Authors: Zhang Zheren , Xue Yicheng , Xu Zheng 
Published: August 2022

AbstractIn the construction of the new‐type power system, inverters with the synchronous machine characteristics are required. Here, the versatile static synchronous machine (VSSM) and its reference machine following control strategy are proposed. By integrating the battery energy storage system (BESS) into the modular multilevel converter (MMC), the VSSM has more operational flexibility than a conventional synchronous generator. Then, the basic theory of the reference synchronous machine is discussed, indicating that the VSSM can acquire the synchronous machine characteristics by following the operation of the reference synchronous machine. Based on the above principle, the implementation of the reference machine following control strategy is presented, including the synchronous machine mode and the current limiting mode. The case studies are performed on a 2‐area test system and a modified IEEE 39‐bus test system by time‐domain simulation in PSCAD/EMTDC. The simulation results verify the synchronous machine characteristics in the proposed VSSM with the machine following control, and sheds some light on the potential of the VSSM in the new‐type power system.
DoG-HiT: A novel VLBI multiscale imaging approach
Authors: Müller H. , Lobanov A. P. 
Published: August 2022

Context. Reconstructing images from very long baseline interferometry (VLBI) data with a sparse sampling of the Fourier domain (uv-coverage) constitutes an ill-posed deconvolution problem. It requires application of robust algorithms, maximizing the information extraction from all of the sampled spatial scales, and minimizing the influence of the unsampled scales on image quality.
Aims. We develop a new multiscale wavelet deconvolution algorithm, DoG-HiT, for imaging sparsely sampled interferometric data, which combines the difference of Gaussian (DoG) wavelets and hard image thresholding (HiT). Based on DoG-HiT, we propose a multistep imaging pipeline for analysis of interferometric data.
Methods. DoG-HiT applies the compressed sensing approach to imaging by employing a flexible DoG wavelet dictionary, which is designed to adapt smoothly to the uv-coverage. It uses closure properties as data fidelity terms only, initially, and performs nonconvex, nonsmooth optimization by an amplitude-conserving and total-flux-conserving, hard thresholding splitting. DoG-HiT calculates a multiresolution support as a side product. The final reconstruction is refined through self-calibration loops and imaging with amplitude and phase information applied for the multiresolution support only.
Results. We demonstrate the stability of DoG-HiT, and benchmark its performance against image reconstructions made with the CLEAN and regularized maximum-likelihood (RML) methods using synthetic data. The comparison shows that DoG-HiT matches the super-resolution achieved by the RML reconstructions and surpasses the sensitivity to extended emission reached by CLEAN.
Conclusions. The application of regularized maximum likelihood methods, outfitted with flexible multiscale wavelet dictionaries, to imaging of interferometric data, matches the performance of state-of-the art convex optimization imaging algorithms and requires fewer prior and user-defined constraints.
Abell 1033: Radio halo and gently reenergized tail at 54 MHz
Authors: Edler H. W. , de Gasperin F. , Brunetti G. , Botteon A. , Cuciti V. , van Weeren R. J. , Cassano R. , Shimwell T. W. , Brüggen M. , Drabent A. 
Published: August 2022

Context. Abell 1033 is a merging galaxy cluster of moderate mass (M500 = 3.24 × 1014 M⊙). It hosts a broad variety of diffuse radio sources that are linked to different astrophysical phenomena. The most peculiar phenomenon is an elongated feature with an ultra-steep spectrum that is the prototype of the category of gently reenergized tails (GReET). Furthermore, the cluster hosts sources that were previously classified as a radio phoenix and a radio halo.
Aims. We aim to improve the understanding of the cosmic-ray acceleration mechanisms in galaxy clusters in a frequency and mass range that has been poorly explored so far.
Methods. To investigate the ultra-steep synchrotron emission in the cluster, we performed a full direction-dependent calibration of a LOFAR observation centered at 54 MHz. We analyzed this observation together with recalibrated data of the LOFAR Two-meter Sky Survey at 144 MHz and an archival GMRT observation at 323 MHz. We performed a spectral study of the radio galaxy tail that is connected to the GReET to test whether the current interpretation of the source agrees with observational evidence below 100 MHz. Additionally, we employed a Markov chain Monte Carlo code to fit the halo surface brightness profile at different frequencies.
Results. We report an extreme spectral curvature for the GReET. The spectral index flattens from
α144 MHz323 MHz ≈ -4 to α144 MHz54 MHz ≈ -2
. This indicates the presence of a cutoff in the electron energy spectrum. At the cluster center, we detect the radio halo at 54, 144, and at lower significance at 323 MHz. We categorize it as an ultra-steep spectrum radio halo with a low-frequency spectral index α = −1.65 ± 0.17. Additionally, with a radio power of P150 MHz = 1.22 ± 0.13 × 1025 W Hz−1, it is found to be significantly above the correlations of radio power to cluster mass reported in the literature. Furthermore, the synchrotron spectrum of the halo is found to further steepen between 144 and 323 MHz, in agreement with the presence of a break in the electron spectrum, which is a prediction of homogeneous reacceleration models.
Influence of grain growth on CO2 ice spectroscopic profiles
Authors: Dartois E. , Noble J. A. , Ysard N. , Demyk K. , Chabot M. 
Published: August 2022

Context. Interstellar dust grain growth in dense clouds and protoplanetary disks, even when moderate, affects the observed interstellar ice profiles as soon as a significant fraction of dust grains are in the size range close to the wave vector at the considered wavelength. The continuum baseline correction made prior to analysing ice profiles influences the subsequent analysis and hence the estimated ice composition, which are typically obtained by band fitting using thin film ice mixture spectra.
Aims. We explore the effect of grain growth on the spectroscopic profiles of ice mantle constituents, focusing particularly on carbon dioxide, with the aim of understanding how it can affect interstellar ice mantle spectral analysis and interpretation.
Methods. Using the discrete dipole approximation for scattering and absorption of light, the mass absorption coefficients of several distributions of grains – composed of ellipsoidal silicate cores with water and carbon dioxide ice mantles – are calculated. A few models also include amorphous carbon in the core and pure carbon monoxide in the ice mantle. We explore the evolution of the size distribution starting in the dense core phase in order to simulate the first steps of grain growth up to three microns in size. The resulting mass absorption coefficients are injected into RADMC-3D radiative transfer models of spherical dense core and protoplanetary disk templates to retrieve the observable spectral energy distributions. Calculations are performed using the full scattering capabilities of the radiative transfer code. We then focus on the particularly relevant calculated profile of the carbon dioxide ice band at 4.27 µm.
Results. The carbon dioxide anti-symmetric stretching mode profile is a meaningful indicator of grain growth. The observed profiles towards dense cores obtained with the Infrared Space Observatory and Akari satellites already show profiles possibly indicative of moderate grain growth.
Conclusions. The observation of true protoplanetary disks at high inclination with the James Webb Space Telescope should present distorted profiles that will allow constraints to be placed on the extent of dust growth. The more evolved the dust size distribution, the more the extraction of the ice mantle composition will require both understanding and taking grain growth into account.
Evolution of massive stars with new hydrodynamic wind models
Authors: Gormaz-Matamala A. C. , Curé M. , Meynet G. , Cuadra J. , Groh J. H. , Murphy L. J. 
Published: August 2022

Context. Mass loss through radiatively line-driven winds is central to our understanding of the evolution of massive stars in both single and multiple systems. This mass loss plays a key role in modulating massive star evolution at different metallicities, especially in the case of very massive stars (M* ≥ 25 M⊙).
Aims. Here we present evolutionary models for a set of massive stars, introducing a new prescription for the mass-loss rate obtained from hydrodynamical calculations in which the wind velocity profile, v(r), and the line-acceleration, gline, are obtained in a self-consistent way. These new prescriptions cover most of the main sequence phase of O-type stars.
Methods. We made a grid of self-consistent mass-loss rates Ṁsc for a set of standard evolutionary tracks (i.e. using the old prescription for mass-loss rate) with different values for initial mass and metallicity. Based on this grid, we elaborate a statistical analysis to create a new simple formula for predicting the values of Ṁsc from the stellar parameters alone, without assuming any extra condition for the wind description. Therefore, replacing the mass-loss rates at the main sequence stage provided by the standard Vink’s formula with our new recipe, we generate a new set of evolutionary tracks for MZAMS  =  25, 40, 70, and 120 M⊙ and metallicities Z  =  0.014 (Galactic), Z  =  0.006 (LMC), and Z  =  0.002 (SMC).
Results. Our new derived formula for mass-loss rate predicts a dependence Ṁ ∝ Za, where a is no longer constant but dependent on the stellar mass: ranging from a ∼ 0.53 when M* ∼ 120 M⊙, to a ∼ 1.02 when M* ∼ 25 M⊙. We find important differences between the standard tracks and our new self-consistent tracks. Models adopting the new recipe for Ṁ (which starts off at around three times weaker than the mass-loss rate from the old formulation) retain more mass during their evolution, which is expressed as larger radii and consequently more luminous tracks over the Hertzsprung-Russell diagram. These differences are more prominent for the cases of MZAMS  =  70 and 120 M⊙ at solar metallicity, where we find self-consistent tracks are ∼0.1 dex brighter and retain up to 20 M⊙ more than with the classical models using the previous formulation for mass-loss rate. Later increments in the mass-loss rate for tracks when self-consistency is no longer used, attributed to the LBV stage, produce different final stellar radii and masses before the end of the H-burning stage, which are analysed case by case. Moreover, we observe remarkable differences in the evolution of the radionuclide isotope 26Al in the core and on the surface of the star. As Ṁsc is weaker than the commonly adopted values for evolutionary tracks, self-consistent tracks predict a later modification in the abundance of 26Al in the stellar winds. This new behaviour could provide useful information about the real contribution of this isotope from massive stars to the Galactic interstellar medium.
Numerical study of the effect of the corrugated baffle on the acoustic characteristics of the combustion chamber
Authors: Salarvand Hamid , Shateri Ali Reza , Nadooshan Afshin Ahmadi , Karimipour Iman 
Published: August 2022

Combustion instability caused by the amplification of sound waves is called acoustic or high-frequency instability, which can cause severe damage to the system. Adding baffles is one of the methods of passive instability control. Depending on the geometry of the chamber and the type of application, different baffles are used. In this research, the effect of the longitudinal corrugated baffle on the acoustic characteristics of the combustion chamber is investigated numerically. The quality of each baffle configuration is determined by examining their influence on the essential parameters such as natural frequency shift and damping factor. Modal and harmonic analyses for the acoustic field are conducted to investigate the effect of baffles installed in the combustion chamber. According to the obtained results, the addition of baffle shifts resonant frequencies. In other words, a combustor with baffles is more effective in controlling the instabilities than that without baffles. In addition, it increases the damping factor in the first–second circumferential (tangential) modes, making the system more stable. Also, a quantitative assessment of the acoustics by adding baffles shows that combustion chamber finds a better condition from stability point of view, and the bandwidth increase affects the combustion stability.
The Global Threat of Non-Communicable Diseases – Cost and
Drivers for Diabetes Type 2 in Germany
Authors: Scherdjow Anna , Kiefer Sophie , Lüske Jonas , Althaus Annina Eva 
Published: August 2022

Abstract
Background Since the last decade, non-communicable diseases, most commonly
diabetes mellitus (DM2) have become the main threat to global health. Based on a
prevalence of 9 million diabetic patients per year, DM2 constitutes a
considerable medical and economic burden in Germany. The healthcare spending and
its cost drivers are not yet sufficiently known.
Aims of the study The primary objective of this study was to describe the
resource use in health care and the cost of DM2 treatment in Germany, focusing
on the most significant cost drivers and opportunities for cost-savings. The
secondary objective was to analyse the impact of technical progress on diabetes
care.
Methods A systematic literature search was conducted in PubMed and Embase.
Following the PRISMA guidance, the review identified the study design,
epidemiological approach, analytical perspective, and data collection approach
in each of the included studies.
Results From 1.965 records, the final sample included 41 articles. The
annual diabetes-specific direct costs of DM2 ranged from 542 € to 6.323
€ per patient. The most used method was the incremental or excess cost
approach (1.8-fold higher costs compared to individuals without DM2). Intangible
costs – such as psychological well-being - were randomly considered in
the existing cost-of-illness studies.Confirmed risk factors included physical inactivity, obesity, genetic
predispositions, and tobacco use.The major cost drivers are demographic change with aging, increasing obesity, the
availability of medications and therapies and the increased use of medical
services by patients.
Conclusion DM2, based on the results of this study, constitutes a
considerable medical and economic burden in Germany and has a serious impact on
the government health expenditures.
Polycaprolacton/Polylactid-Membran kann Laminektomie-induziertes Wachstum von CGRP- und SP-immunpositiven Nervenfasern in der Dura mater lumbalis von Ratten nicht
verhindern
Authors: Gipperich Tobias , Hanesch Ulrike , Guido Saxler , Schulze Bövingloh Albert 
Published: August 2022

Zusammenfassung
Hintergrund Mechanismen und Prävention des Failed-Back-Surgery-Syndroms sind im klinischen Kontext kaum bekannt. Tierexperimentell konnte gezeigt werden, dass Laminektomien das
Wachstum von mutmaßlich nozizeptiven peptidergen Afferenzen in der Dura mater lumbalis von Ratten induziert.
Ziel Evaluierung, ob die postoperative Anwendung einer Polycaprolacton-Polylactid-Membran (Mesofol) die sensorische Hyperinnervation hemmt.
Material/Methoden Erwachsene Lewis-Ratten wurden in 3 Gruppen unterteilt: Kontrolle (keine Manipulation), Laminektomie und Laminektomie + Mesofol. Sechs Wochen postoperativ wurden
die Durae entfernt, CGRP- und SP-haltige Afferenzen immunhistochemisch markiert und deren Innervierungsdichte bestimmt.
Ergebnisse In den Kontrollen wurden die CGRP- und SP-positiven Neurone überwiegend in den ventralen, jedoch nur spärlich in den dorsalen Abschnitten der jeweiligen Dura gefunden.
Nach Laminektomie nahm ventral die Anzahl der immunpositiven Afferenzen signifikant zu, was in einem dichten Netzwerk von Nervenfasern resultierte. In den dorsalen Regionen wurde ebenfalls
eine Zunahme immunpositiver Nervenfasern sowie neuronales Aussprossen und Wachstum beobachtet. Das Bedecken der Durae mit Mesofol nach Laminektomie hatte keinen signifikanten Einfluss auf
das Nervenfaserwachstum.
Schlussfolgerung Die Verwendung von Mesofol konnte den Laminektomie-induzierten Dichteanstieg der peptidergen Afferenzen weder verhindern noch signifikant herabsetzen.
Design and Rationale of the HANSE Study: A Holistic German Lung Cancer Screening Trial Using Low-Dose Computed Tomography
Authors: Vogel-Claussen Jens , Lasch Florian , Bollmann Benjamin-Alexander , May Katharina , Kuhlmann Alexander , Schmid-Bindert Gerald , Kaaks Rudolf , Barkhausen Jörg , Bohnet Sabine , Reck Martin 
Published: August 2022

AbstractDespite the high prevalence and mortality of lung cancer and proven effectiveness of low-dose computed tomography (LDCT) to reduce mortality, Germany still lacks a national screening program. The German Institute for Quality and Efficiency in Health Care (IQWiG) and the Federal Office for Radiation Protection (BfS) both published positive scientific evaluations recommending a quality-controlled national screening program. IQWiG underlined the importance of a clear risk definition, integrated smoking cessation programs, and quality assurance, highlighting the necessity of procedural optimization.In the HANSE study, former and current smokers aged 55–79 years are assessed for their lung cancer risk by the NELSON and PLCOM2012 risk scores. 5000 high-risk participants, defined as PLCOM2012 6-year risk ≥ 1.58 % or fulfilling NELSON risk inclusion criteria, will be screened by LDCT at baseline and after 12 months. Lung nodules are analyzed by a modified Lung-RADS 1.1 score of the HANSE study, and values of emphysema and coronary calcium are determined and randomly reported to the participants. 7100 low-risk participants serve as a control. All patients are followed-up for up to 10 years. The sensitivity and specificity of the two risk assessments and LDCT screening, effects of the randomized LDCT reporting, efficiency of lung nodule management, and several other factors are assessed to analyze the success and quality of the holistic screening program.The HANSE study is designed as a holistic lung cancer screening study in northern Germany to answer pressing questions for a successful implementation of an effective German lung cancer screening program.
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