bluuebunny/crossref_metadata_2025 huggingface dataset:
Synergistic effect of oxygen vacancies and Ni particles over the ZnWO4/CdS heterostructure for enhanced photocatalytic reduction and oxidation activities
Authors: Zhang Houfeng , Gan Shenglong , Hou Dongfang , Qiao Xiu-qing , Chi Ruan , Li Dong-Sheng
Published: December 2022

A hybrid photocatalyst of oxygen vacancies-decorated ZnWO4/CdS–Ni greatly boosts the photocatalytic reduction and oxidation activities, which is due to the Z-scheme heterojunction after introducing oxygen vacancies and bifunctional Ni particles.
Three-component acyloxylation of diazo compounds with carboxylic acids and azadienes
Authors: Lin Meng-Ling , Zheng Ting , Liu Hao , Wang Ying-Xu , Dong Lin
Published: December 2022

Despite many studies on benzofuran-derived azadiene being reported, multi-component studies have scarcely been reported on this heterocyclic skeleton.
Discovery of a simple iron catalyst reveals the intimate steps of C–H amination to form C–N bonds
Authors: Stroek Wowa , Albrecht Martin
Published: December 2022

Fe(HMDS)2 is an efficient catalyst for the intramolecular C–H amination using azides as nitrene precursors; its simplicity offers crucial insights into the mechanism of this reaction.
Carborane-thiol protected copper nanoclusters: stimuli-responsive materials with tunable phosphorescence
Authors: Jana Arijit , Jash Madhuri , Dar Wakeel Ahmed , Roy Jayoti , Chakraborty Papri , Paramasivam Ganesan , Lebedkin Sergei , Kirakci Kaplan , Manna Sujan , Antharjanam Sudhadevi , Machacek Jan , Kucerakova Monika , Ghosh Sundargopal , Lang Kamil , Kappes Manfred M. , Base Tomas , Pradeep Thalappil
Published: December 2022

A new class of flexible tetranuclear copper nanoclusters protected by carborane-thiols having stimuli-responsive tunable solid state phosphorescence.
Bilayer dressing based on aerogel/electrospun mats with self-catalytic hydrogen sulfide generation and enhanced antioxidant ability
Authors: Han Xiao , Wang Lijuan , Shang Yushuang , Liu Xu , Kang Inn-kyu , Shen Jian , Yuan Jiang
Published: December 2022

A bilayer dressing based on aerogel/electrospun mats with self-catalytic hydrogen sulfide generation and enhanced antioxidant ability was fabricated. The dressing could reduce inflammation and accelerate wound healing.
¿Cómo ha afectado el COVID-19 a traumatólogos y residentes de traumatología en Chile?
Authors: Ramírez Constanza , Stefano Pía , Ocampo Juan C. , Yáñez Rodrigo , Gündel Alejandro
Published: December 2022

Introducción Desde marzo del 2020, Chile se ha visto afectado por la pandemia por coronavirus 2019 (coronavirus disease 2019, COVID-19, en inglés), que ha provocado alteraciones en todo el mundo, causando un gran impacto en los servicios de salud y el personal sanitario.

Objetivo Describir características demográficas y laborales relacionadas al contagio de COVID-19 en traumatólogos y residentes de traumatología en Chile.

Métodos Realizamos una encuesta on-line, solicitando información demográfica, datos laborales, exposición y contagio de COVID-19, sintomatología y medidas de protección.

Resultados En total, 567 médicos contestaron. De ellos, 37 (6,4%) tuvieron COVID-19, sin diferencia significativa respecto a género. Se observó mayor contagio entre residentes, 9 de 73 (12,3%), que entre traumatólogos, 28 de 494 (5,7%), así como mayor contagio entre quienes trabajaron más de 60 horas (p <0,05). De los contagiados, 31 (83,8%) eran de la Región Metropolitana (RM), cuyo contagio es significativamente mayor que en el resto de las regiones (p < 0,05). Sólo 8 (21,6%) de los contagiados presentaban antecedentes médicos. Requirieron hospitalización 3 (5,4%), 1 de los cuales en Unidad de Cuidados Intensivos (UCI), y el resto fue manejado en forma domiciliaria. El sitio de contagio más frecuente fue el trabajo, siendo las áreas comunes las más sospechadas, seguidas de la atención ambulatoria y las áreas de hospitalización traumatológica. Un 40.5% (15) reportó haber contagiado a alguien más. Hubo además un impacto en los ingresos de los traumatólogos: un 14,8% (84) refirió una disminución menor al 20%, y un 45%, disminución mayor al 50%. Esta fue mayor en los traumatólogos que en los residentes, y en aquellos de la RM que en otras regiones (p < 0,05).

Conclusión Aunque la actividad traumatológica se ha visto disminuida por la pandemia, los traumatólogos se han visto expuestos al riesgo de contagio por COVID-19. El trabajo parece ser el lugar de mayor riesgo, sobre todo las áreas comunes.

Nivel de Evidencia V.
Locking Compression Plate Fixation of Feline Acetabular Fractures: Application, Complications and Perioperative Outcome
Authors: Murugarren Maider , Piana Francesco , Kalff Stephen , Solano Miguel
Published: December 2022

Objectives The aim of this study was to report the use, complications and perioperative outcome of locking compression plates (LCP) for acetabular fracture fixation in feline patients.

Study Design Medical records were reviewed for cats presented with acetabular fractures between 2011 and 2019. Only cases that involved open reduction and internal fixation with at least one LCP and had a minimum of 5-week postoperative follow-up were included. Long-term follow-up was based on the Feline Musculoskeletal Pain Index.

Results Fifteen cats with 15 acetabular fractures met the inclusion criteria. Locking compression plates were used as a sole method of fixation in 11/15 cases, while with other ancillary implants in 4/15 cases. There were two minor complications related to the LCP consisting of a single screw backing out. Two major perioperative complications not related to the locking implants were described and required further surgical treatment. At the last clinical follow-up (median 46 days: 38–88 days), function was described as full for 7/15 cats, and acceptable for 8/15 cats. The Feline Musculoskeletal Pain Index questionnaire was completed by 9/15 owners at a median of 2,332 days; all owners reported their cats had minimal impairment.

Clinical Significance Based on our results, LCP is a suitable implant for acetabular fracture fixation in cats, associated with a satisfactory outcome. Complications were similar to previously reported with other methods.
Chronic insomnia disorder as risk factor for stroke: a systematic review
Authors: Silva Luiz Augusto Soares , Amaral Mateus Molin do , Grassi Vanise , Palmeira André Luiz Rodrigues
Published: December 2022

Background Stroke is one of the main causes of mortality worldwide. Nonetheless, there are still risk factors that have not been fully elucidated, such as chronic insomnia disorder.

Objective To evaluate the association between chronic insomnia disorder and the risk of stroke in adults, through a systematic review.

Methods Multiple studies available in the Embase, Lilacs, and Medline platforms were evaluated in English, Spanish, French, and Portuguese. The selection of papers was restricted to those that had investigated the association between chronic insomnia disorder and stroke in adults, regardless of gender or nationality, without a previous history of stroke. The data was extracted with the Cochrane Effective Practice and Organization of Care (EPOC) form. The risk of bias was evaluated by the EPOC Risk of bias tool.

Results A total of 138 articles were identified. After a detailed evaluation with the eligibility criteria, four articles were included in the present systematic review. Three of them recognized the association between chronic insomnia disorder and stroke. The comparative analysis was limited, since the studies used distinct insomnia classifications. Regarding the risk of bias, the analysis displayed an important risk in the selection and allocation of participants, besides the use of own insomnia diagnosis criteria, disrespecting chronology and factors indicated by already established classifications.

Conclusions There is not enough data to determine that chronic insomnia disorder is a risk factor for stroke. The present study points out the existence of a possible relationship between insomnia disorder and stroke, suggesting that further studies adopt standardized criteria and instruments.
Stroke-related mortality analysis in Paraná, Brazil, over 10 years
Authors: Ducci Renata Dal-Prá , Tessaro Camila Lorenzini , Fontes Daniela Piera , Fraga Gabriel Schier de , Cirino Raphael Henrique Déa , Neto Francisco Diego Negrão Lopes , Zetola Viviane de Hiroki Flumignan , Lange Marcos Christiano
Published: December 2022

Background Stroke is the second leading cause of death and disability around the world.

Objective The purpose of this study is to evaluate the age- and sex-specific mortality rates related to stroke in the state of Paraná, Brazil, between 2007 and 2016.

Methods In this cross-sectional study, residents in the state of Paraná were selected by death certificates (from 2007–2016); the basic cause of death was stroke. A descriptive analysis was performed, and mortality rates were calculated with a 95% confidence interval (95% CI) for each year.

Results From 2007 to 2016, there were 62,607 deaths in the state of Paraná due to stroke. Most individuals had medical assistance before death (85.7% in 2007 versus 83.9% in 2016), and most of these deaths occurred in hospitals (73.6% in 2007 versus 74.8% in 2016). Death rates due to stroke increased from 138 (95% CI 135–142) to 163 (95% CI 159–166) per 100,000 inhabitants. This raise occurred mainly in those over 79 years old. For the ages groups of 34 to 44 and 44 to 54 years, mortality rate decreased.

Conclusions In the past 15 years, despite the advances in the diagnosis and treatment of stroke, there has been an increase in mortality due to stroke in the state of Paraná. This fact is possibly associated with the aging of the population because there was a more pronounced increase in the group over 79 years old. Thus, new health strategies are necessary to improve the survival and quality of life of poststroke individuals.
Knowledge and emotional attitudes of health care practitioners regarding patients with psychogenic nonepileptic seizures
Authors: Saker Thani Sheikh , Katson Mark , Herskovitz Sari Eran , Herskovitz Moshe
Published: December 2022

Background Psychogenic nonepileptic seizures (PNESs) are paroxysmal events that resemble epileptic seizures without concomitant changes in electroencephalograms (EEGs) or any other physiological cause. These seizures are one of the most common and dramatic conversion disorders. First responders treat many PNES patients with unnecessary emergency abortive medication and sometimes even intubate them. Several of our PNES patients have complained they have experienced harsh attitudes from health care practitioners (HCPs), especially during their stay in the emergency room (ER).

Objective To assess the emotional attitude of HCPs toward PNES patients.

Methods We handed a questionnaire containing 23 questions regarding PNES patients to HCPs from emergency medicine, internal medicine, and neurology disciplines. The questions dealt with three categories: diagnosis, management, and emotional attitudes.

Results Overall, 47 HCPs participated in this study: 11 ER, 18 internal medicine, and 18 neurology practitioners. The HCP from those disciplines showed high knowledge and good management practice of PNES patients. On the other hand, the HCPs agreed with most emotional attitude statements regarding PNES patients, reflecting a high percentage of negative emotional attitudes toward this group of patients. We did not find any correlation between negative emotional attitude and HCP department, profession, or seniority.

Conclusions Although HCPs in our center perform good management practice regarding PNES patients, most reported a negative emotional attitude. This finding implies that what PNES patients feel regarding the harsh attitudes is also reflected by HCP views. Emotional attitudes towards PNES patients may not depend solely on the level of knowledge of the HCPs.
Comparison of Two Bandage Splint Constructs in an Ex Vivo Equine Metacarpal Fracture Model
Authors: Granello M. E. , Weatherall K. M. , Lutter J. D. , Beard W. L.
Published: December 2022

Objectives The aim of this study was to compare the deflection distance, deflection angle and pre-loading sub-bandage pressure of a transverse, mid-metacarpal fracture in an equine cadaver limb when loaded in bending while stabilized with either a Robert Jones Bandage (RJB) or a single-stack bandage (SS), each containing two orthogonal splints.

Study Design In an ex vivo experimental study, forelimb pairs from eight horses were collected, and one forelimb from each pair was assigned to either the SS or RJB groups. A transverse osteotomy was performed at the midpoint of the metacarpus. After bandaging, the limbs were loaded in bending. Pre-loading sub-bandage pressure, pre- and post-loading radiographs and post-loading deflection distance measurements were taken. Dorsopalmar radiographs were used to measure the loaded deflection angle.

Results There was no significant difference between RJB and SS constructs in change in deflection angle (10.7 ± 3.0 degrees vs. 9.8 ± 2.6 degrees; p = 0.5) or deflection distance (13.1 ± 2.6 cm vs. 11.4 ± 3.1 cm; p = 0.2). Sub-bandage pressures were significantly greater for the SS than the RJB both dorsally and laterally.

Conclusion The SS splint construct resists bending forces similarly to the RJB splint construct in an ex vivo transverse, metacarpal fracture model. The SS splint construct may be a useful alternative to the RJB splint construct in field situations for metacarpal fracture stabilization.
Complex-valued time series based solar irradiance forecast
Authors: Voyant Cyril , Lauret Philippe , Notton Gilles , Duchaud Jean-Laurent , Garcia-Gutierrez Luis , Faggianelli Ghjuvan Antone
Published: December 2022

A new method for short-term probabilistic forecasting of global solar irradiance from complex-valued time series is explored. The measurement defines the real part of the time series while the estimate of the volatility is the imaginary part. A complex autoregressive model (capable to capture quick fluctuations) is then applied with data gathered on the Corsica island (France). Results show that even if this approach is easy to implement and requires very little resource and data, both deterministic and probabilistic forecasts generated by this model are in agreement with experimental data (root mean square error ranging from 0.196 to 0.325 considering all studied horizons). In addition, it exhibits sometimes a better accuracy than classical models such as the Gaussian process, bootstrap methodology, or even more sophisticated models such as quantile regression. Many studies and many fields of physics could benefit from this methodology and from the many models that could result from it.
Ostwald ripening of aqueous microbubble solutions
Authors: Inoue Sota , Kimura Yasuyuki , Uematsu Yuki
Published: December 2022

Bubble solutions are of growing interest because of their various technological applications in surface cleaning, water treatment, and agriculture. However, their physicochemical properties, such as the stability and interfacial charge of bubbles, are not fully understood yet. In this study, the kinetics of radii in aqueous microbubble solutions are experimentally investigated, and the results are discussed in the context of Ostwald ripening. The obtained distributions of bubble radii scaled by mean radius and total number were found to be time-independent during the observation period. Image analysis of radii kinetics revealed that the average growth and shrinkage speed of each bubble is governed by diffusion-limited Ostwald ripening, and the kinetic coefficient calculated using the available physicochemical constants in the literature quantitatively agrees with the experimental data. Furthermore, the cube of mean radius and mean volume exhibit a linear time evolution in agreement with the Lifshitz–Slezov–Wagner (LSW) theory. The coefficients are slightly larger than those predicted using the LSW theory, which can be qualitatively explained by the effect of finite volume fraction. Finally, the slowdown and pinning of radius in the shrinkage dynamics of small microbubbles are discussed in detail.
Sport specialization in Swedish football players: Investigating a model of antecedents and outcomes
Authors: Söderström Tor , Garn Alex C.
Published: December 2022

Drawing on data from the present and former football players (N = 1026) selected to a national football talent programme at the age of 15, this study explores a model of sport specialisation. We examined three specific aspects of sport specialisation including early football specialisation, participation in youth elite football training environments (i.e. academies) and enrolment in upper secondary football specialisation schools. Antecedents of these sport specialisation factors included gender (i.e. sociocultural), grit (i.e. personality) and perceptions of family finances (i.e. social). Outcomes focused on adult football participation at the age of 21 including elite skill acquisition (i.e. playing elite football) and personal development (i.e. participation in non‐elite football). Findings revealed that females were less likely to gain access to elite football training or school specialisation environments. There was also a positive association between grit and participation in elite training environments. In terms of outcomes, players, who got trained in elite training environments during adolescence, were twice as likely to play elite football at the age of 21, while those who attended football specialisation schools were more likely to participate in non‐elite football at the age of 21. Early specialisation was not associated with either adult participation outcome. This is one of the few studies to date addressing diverse antecedents and outcomes of sport specialisation factors. Understanding how sport specialisation practices relate to future skill acquisition and personal development can provide guidance for maximising the benefits of youth sport programming.
A Retinex-based variational model for noise suppression and nonuniform illumination correction in corneal confocal microscopy images
Authors: Han Rui , Tang Chen , Xu Min , Lei Zhenkun
Published: December 2022

Objective. Corneal confocal microscopy (CCM) image analysis is a non-invasive in vivo clinical technique that can quantify corneal nerve fiber damage. However, the acquired CCM images are often accompanied by speckle noise and nonuniform illumination, which seriously affects the analysis and diagnosis of the diseases. Approach. In this paper, first we propose a variational Retinex model for the inhomogeneity correction and noise removal of CCM images. In this model, the Beppo Levi space is introduced to constrain the smoothness of the illumination layer for the first time, and the fractional order differential is adopted as the regularization term to constrain reflectance layer. Then, a denoising regularization term is also constructed with Block Matching 3D (BM3D) to suppress noise. Finally, by adjusting the uneven illumination layer, we obtain the final results. Second, an image quality evaluation metric is proposed to evaluate the illumination uniformity of images objectively. Main results. To demonstrate the effectiveness of our method, the proposed method is tested on 628 low-quality CCM images from the CORN-2 dataset. Extensive experiments show the proposed method outperforms the other four related methods in terms of noise removal and uneven illumination suppression. Significance This demonstrates that the proposed method may be helpful for the diagnostics and analysis of eye diseases.
Tuning of band gap by anions (Cl, Br, I) of double perovskites Rb2AgAsX6 (Cl, Br, I) for solar cells and thermoelectric applications
Authors: Nazir Ghazanfar , Mahmood Q , Hassan M , AL-Anazy Murefah Mana , Kattan Nessrin A , Sfina N , Amin Mohammed A , Mera Abeer , Somaily H H
Published: December 2022

The high stability, lead free, environment friendly and excellent performance of double perovskites make them emerging materials for solar cells and thermoelectric generators. Therefore, here optical, electronic, and thermoelectric characteristics of Rb2AgAsX6 (X = Cl, Br, I) are studied comprehensively by first principle approach. The thermodynamic stability is ensured through formation energy and structural stability by calculating tolerance factor. The studied DPs band gaps are tuned from 2.21 eV to 1.50 eV, and 0.52 eV by the replacing the anions (Cl to Br, and I). The absorption regions from varies from infrared to visible regions which increase their significance for diverse applications in optoelectronics. The broad absorption band of Rb2AgAsI6 in visible region is important for solar cells. Furthermore, the thermoelectric performance has been elaborated by power factor and figure of merit. The ultralow lattice thermal conductivity, and large Seebeck coefficient also increase the figure of merit to realize them for thermoelectric applications.
Magnetocaloric effect and tunable phase transition exponents of SrRuO 3/mica heterostructure with varied mechanical bending
Authors: Wang Jing , Fan Jiyu , Liu Fengguang , Zu Lin , Zheng Huan , Liu Hao , Ma Chunlan , Wang Caixia , Hu Dazhi , Zhu Yan , Yang Hao
Published: December 2022

Exploitation and enhancement of the mechanical strain to modulate the magnetic properties are crucial for developing conformal wearable magnetic-electronic devices. However, the mechanical strain how to regulate the magnetic properties remains unclear for flexible thin film. Here, (111)-oriented SrRuO3 thin films are epitaxially grown on flexible mica substrates, and the influence of the mechanical bending on magnetic properties is studying by altering the curvature of the SrRuO3/BaTiO3/Mica heterostructure. The results show that the phase transition temperature does not reveal a significant dependence on both of convex and concave bending but they play a contrary role on the magnetic entropy change. Namely, the tensile stress (convex) increases the magnetic entropy change while the compressive stress (concave) decreases it. Moreover, based on the scale analysis method, we find that both bending states are directly correlated with the change of critical phase transition behavior. We think that the variation of domain wall configuration due to mechanical bending is the main reason for the change of magnetic properties. This study therefore not only identifies a strong magnetic property correlation in the mechanical strain, but also offers an avenue to improve flexible electronic devices with optimized performance.
Analyzing planar galactic halo distributions with fuzzy/cold dark matter models
Authors: Park Sangnam , Bak Dongsu , Lee Jae-Weon , Park Inkyu
Published: December 2022

We perform a numerical comparison between the fuzzy dark matter model
and the cold dark matter model, focusing on
formation of satellite galaxy planes around massive galaxies.
Such galactic dynamics with controlled initial subhalo configurations are
investigated
using GADGET2 for the cold dark matter and PyUltraLight for the fuzzy dark matter,
respectively.
We demonstrate that satellite galaxies in the fuzzy dark matter side have a tendency
to form more flattened and corotating satellite systems than in the cold dark matter side mainly due to the dissipation by
the gravitational cooling effect of the fuzzy dark matter.
Our simulations
with the fuzzy dark matter typically show
the minor-to-major axis ratio c/a
of the satellite galaxy planes to be 0.21 ∼ 0.30; this well matches the current observed value for the Milky Way.
Optimization of the gain chip for optically pumped semiconductor disk lasers
Authors: Hua Ling-Ling , Zhuang Bi-Hui , Mao Lin , Tian Jin-Rong , Song Yan-Rong
Published: December 2022

Strain-compensated quantum wells (QWs) could greatly improve the performance of semiconductor disk lasers, such as improving the epitaxy quality of the semiconductor gain chip and obtaining a higher gain. To optimize the output characteristics of the semiconductor gain chip, the strain-compensated thickness, well depth, band energy, emission wavelength, and peak gain versus In and P compositions are investigated in detail. The results show that increasing the P composition of the strain-compensated layer will slightly reduce the emission wavelength, deepen the well depth, and increase the peak gain. But the P composition is not the higher the better. When designing a gain chip, it should have a pre-offset between the emission wavelength of the QWs at room temperature and the target wavelength of the laser at an intense pump, and the pre-offset values of the wavelength should be designed deliberately to guarantee the resonant periodic gain structure working normally when the temperature in the active region approaches the desired value. This theoretical investigation may provide guidance for optimizing the laser performance of semiconductor disk lasers and other QW lasers.
Research on eigenstate current control technology of Flash-based FPGA
Authors: Shan Yueer , Cao Zhengzhou , Liu Guozhu
Published: December 2022

To solve the Flash-based FPGA in the manufacturing process, the ion implantation process will bring electrons into the floating gate of the P-channel Flash cell so that the Flash switch is in a weak conduction state, resulting in the Flash-based FPGA eigenstate current problem. In this paper, the mechanism of its generation is analyzed, and four methods are used including ultraviolet light erasing, high-temperature baking, X-ray irradiation, and circuit logic control. A comparison of these four methods can identify the circuit design by using circuit logic to control the path of the power supply that is the most suitable and reliable method to solve the Flash-based FPGA eigenstate current problem. By this method, the power-on current of 3.5 million Flash-based FPGA can be reduced to less than 0.3 A, and the chip can start normally. The function and performance of the chip can then be further tested and evaluated, which is one of the key technologies for developing Flash-based FPGA.
A 4H-SiC semi-super-junction shielded trench MOSFET: p-pillar is grounded to optimize the electric field characteristics
Authors: Wang Xiaojie , Shen Zhanwei , Zhang Guoliang , Miao Yuyang , Li Tiange , Zhu Xiaogang , Cai Jiafa , Hong Rongdun , Chen Xiaping , Lin Dingqu , Wu Shaoxiong , Zhang Yuning , Fu Deyi , Wu Zhengyun , Zhang Feng
Published: December 2022

A 4H-SiC trench gate metal–oxide–semiconductor field-effect transistor (UMOSFET) with semi-super-junction shielded structure (SS-UMOS) is proposed and compared with conventional trench MOSFET (CT-UMOS) in this work. The advantage of the proposed structure is given by comprehensive study of the mechanism of the local semi-super-junction structure at the bottom of the trench MOSFET. In particular, the influence of the bias condition of the p-pillar at the bottom of the trench on the static and dynamic performances of the device is compared and revealed. The on-resistance of SS-UMOS with grounded (G) and ungrounded (NG) p-pillar is reduced by 52% (G) and 71% (NG) compared to CT-UMOS, respectively. Additionally, gate oxide in the GSS-UMOS is fully protected by the p-shield layer as well as semi-super-junction structure under the trench and p-base regions. Thus, a reduced electric-field of 2 MV/cm can be achieved at the corner of the p-shield layer. However, the quasi-intrinsic protective layer cannot be formed in NGSS-UMOS due to the charge storage effect in the floating p-pillar, resulting in a large electric field of 2.7 MV/cm at the gate oxide layer. Moreover, the total switching loss of GSS-UMOS is 1.95 mJ/cm2 and is reduced by 18% compared with CT-UMOS. On the contrary, the NGSS-UMOS has the slowest overall switching speed due to the weakened shielding effect of the p-pillar and the largest gate-to-drain capacitance among the three. The proposed GSS-UMOS plays an important role in high-voltage and high-frequency applications, and will provide a valuable idea for device design and circuit applications.
GaAs radiation-degraded detectors: gamma spectrometry at lowered temperatures
Authors: Sagatova A. , Gal N. , Novak A. , Kotorova S. , Riabukhin O. , Kovacova E. , Zatko B.
Published: December 2022

The GaAs detectors are radiation hard against a few MGy of high-energy (MeV) electrons. The main reason for detector functionality degradation is the reduction of their charge collection efficiency and together with reverse current increase these facts cause the drop of the signal to noise ratio down to close to 1, disabling detector functionality. In this paper, the lowering of detector temperature has improved the spectra of less ionizing particles, the 59.5 keV gamma rays, measured by semi-insulating GaAs pad detectors, which were first degraded by 8 MeV electrons with a dose of 200 kGy. The signal to noise ratio improved by about 30%, from 1.09 at room temperature up to 1.42 at 276 K. The photo-peak was easily distinguishable from the noise during cooling and the calculated detector relative energy resolution improved from 46% at room temperature to 34% at 276 K. A mild decrease in detector charge collection efficiency was observed, by about 5% of its initial value, when cooling the detector to 276 K.
Study of gain, noise, and collection efficiency of GaAs SAM-APDs single pixel
Authors: Colja M. , Cautero M. , Menk R.H. , Palestri P. , Gianoncelli A. , Antonelli M. , Biasiol G. , Zilio S.D. , Steinhartova T. , Nichetti C. , Arfelli F. , De Angelis D. , Driussi F. , Bonanni V. , Pilotto A. , Gariani G. , Carrato S. , Cautero G.
Published: December 2022

III-V-compound semiconductors offer many advantages over silicon-based technologies traditionally used in solid-state photodetectors, especially in hard X-ray applications that require high detection efficiency and short response times. Amongst them, gallium arsenide (GaAs) has very promising characteristics in terms of X-ray absorption and high carrier velocity. Furthermore, implementing charge-multiplication mechanisms within the sensor may become of critical importance in cases where the photogenerated signal needs an intrinsic amplification before being acquired by the front-end electronics. This work reports on the experimental characterization by means of lasers and synchrotron radiation of gain, noise, and charge collection efficiencies of GaAs avalanche photodiodes (APDs), realized by molecular beam epitaxy (MBE), featuring separate absorption and multiplication regions (SAM) and different absorption region thicknesses. These devices have been fabricated to investigate the role of the thickness of the absorption region and of possible traps or defects at the metal-semiconductor interfaces in the collection efficiency in order to lay the groundwork for the future development of thicker GaAs devices for detection of hard X-rays.
Precise measurement of the Bragg curve for 800 MeV/u 238U
ions stopping in polyethylene and its implications for calculation of heavy ion ranges
Authors: Horst Felix , Ferrari Alfredo , Sala Paola , Schuy Christoph , Durante Marco , Weber Uli
Published: December 2022

Stopping power predictions in radiation transport codes are based on the Bethe-Bloch
formula and different corrections. For very heavy ions at relativistic energies the available
experimental data are scarce and therefore verification of stopping power predictions is only
possible to a limited extent.

In this work, a full experimental Bragg curve for
800 MeV/u 238U ions stopping in polyethylene is presented. The
measurements were conducted at the experimental area Cave A at GSI Helmholtzzentrum für
Schwerionenforschung in Darmstadt, Germany. The 800 MeV/u 238U beam was
provided by the SIS18 heavy ion synchrotron. The Bragg curve was measured with a setup consisting
of a binary range shifter and two large area parallel plate ionization chambers. Complementary
Monte Carlo simulations using the FLUKA code were performed and compared with the experimental
Bragg curve. The mean ionization potential of polyethylene was fine-tuned to match the measured
primary ion range with FLUKA simulations. The impact of the Bloch and Mott corrections to the
stopping power calculation were studied by switching them off intentionally in separate
simulations. A detailed description of the implementation of the stopping power formulae and the
Mott correction in FLUKA is provided.

Supplementary data for this article is available online.
Electro-purification studies and first measurement of relative permittivity of TMBi
Authors: Peters S. , Gerke B. , Hannen V. , Huhmann C. , Marquardt N. , Schäfers K. , Yvon D. , Sharyy V. , Weinheimer C.
Published: December 2022

A new type of detector for positron-emission tomography (PET) has been proposed recently, using a heavy organo-metallic liquid — TriMethyl Bismuth (TMBi) — as target material. TMBi is a transparent liquid with the high Z element Bismuth contributing 82% of its mass. 511keV annihilation photons are converted efficiently into photo-electrons within the detector material producing both Cherenkov light and free charge carriers in the liquid. While the optical component enables a fast timing, a charge readout using a segmented anode can provide an accurate position reconstruction and energy determination. The charge measurement requires a high level of purification, as any electronegative contaminants cause signal degradation. In addition to the purity requirements, the reactive nature of TMBi poses many challenges that need to be met until a fully functioning detector for PET applications can be realized. The paper presents an experimental setup that aims to remove electronegative impurities by electrostatic filtering and to characterise the properties of TMBi, e.g. the relative permittivity, for its application as a detector medium for charge read out.
Design, optimization and experimental characterization of RF injectors for high brightness electron beams and plasma acceleration
Authors: Shpakov V. , Alesini D. , Anania M.P. , Behtouei M. , Buonomo B. , Bellaveglia M. , Biagioni A. , Cardelli F. , Carillo M. , Chiadroni E. , Cianchi A. , Costa G. , Del Giorno M. , Faillace L. , Ferrario M. , Del Franco M. , Franzini G. , Galletti M. , Giannessi L. , Giribono A. , Liedl A. , Lollo V. , Mostacci A. , Di Pirro G. , Piersanti L. , Pompili R. , Di Raddo G. , Romeo S. , Silvi G.J. , Stella A. , Vaccarezza C. , Villa F. , Vannozzi A.
Published: December 2022

In this article, we share our experience related to the new photo-injector commissioning at the SPARC_LAB test facility.
The new photo-injector was installed into an existing machine and our goal was not only to improve the final beam parameters themselves but to improve the machine handling in day-to-day operations as well. Thus, besides the pure beam characterization, this article contains information about the improvements, that were introduced into the new photo-injector design from the machine maintenance point of view, and the benefits, that we gained by using the new technique to assemble the gun itself.
Deep learning for track recognition in pixel and strip-based particle detectors
Authors: Bakina O. , Baranov D. , Denisenko I. , Goncharov P. , Nechaevskiy A. , Nefedov Y. , Nikolskaya A. , Ososkov G. , Rusov D. , Shchavelev E. , Sun S.S. , Wang L.L. , Zhang Y. , Zhemchugov A.
Published: December 2022

The reconstruction of charged particle trajectories in tracking detectors is a key problem in the analysis of experimental data for high-energy and nuclear physics. The amount of data in modern experiments is so large that classical tracking methods, such as the Kalman filter, cannot process them fast enough. To solve this problem, we developed two neural network algorithms based on deep learning architectures for track recognition in pixel and strip-based particle detectors. These are TrackNETv3 for local (track by track) and RDGraphNet for global (all tracks in an event) tracking. These algorithms were tested using the GEM tracker of the BM@N experiment at JINR (Dubna) and the cylindrical GEM inner tracker of the BESIII experiment at IHEP CAS (Beijing). The RDGraphNet model, based on a reverse directed graph, showed encouraging results: 95% recall and 74% precision for track finding. The TrackNETv3 model demonstrated a recall value of 95% and 76% precision. This result can be improved after further model optimization.
Sustainable aviation fuels must control induced land use change: an integrated assessment modelling exercise for Brazil
Authors: Fiorini Ana Carolina Oliveira , Angelkorte Gerd , Maia Pedro Luiz , Bergman-Fonte Clarissa , Vicente Clarissa , Morais Taísa , Carvalho Lucas , Zanon-Zotin Marianne , Szklo Alexandre , Schaeffer Roberto , Portugal-Pereira Joana
Published: December 2022

Bio-sustainable aviation fuels (bio-SAFs) are an important pillar of the aviation sector decarbonisation strategy in the mid-term. Here we assess the induced Land-Use Change (LUC) implications of producing bio-SAFs in Brazil under different assumptions of forest conservation governance. We evaluate four bio-SAF routes via two main pathways: the Alcohol-to-Jet (ATJ) and the Hydroprocessed Esters and Fatty Acids (HEFA) syntheses. We chose the most promising agriculture-based feedstocks to produce bio-SAFs in all five macro-regions of Brazil, including sugarcane and maize ethanol to jet and palm and macaw HEFA routes. To this end, we calculated future projections of air transport demand in Brazil and used the Brazilian Land Use and Energy Systems integrated assessment model to estimate LUC greenhouse gas (GHG) emissions within five different levels of bio-SAF blends (10% to 50% of total aviation fuel demand) for each bio-SAFs evaluated. Estimated cumulated emissions vary widely, ranging from a carbon sequestration of −286.8 gCO2e.MJ−1 for a 10% blend of maize ATJ under a controlled deforestation scenario to a release of 15.0 gCO2e.MJ−1 for a 40% blend of high productivity macaw oil HEFA considering historical deforestation rates in the country. Results are highly sensitive to deforestation rate parameters, volume of bio-SAFs produced, the type of feedstock used, and methodological assumptions. Negative LUC GHG emissions were found under controlled deforestation assumptions and in low blends of bio-SAFs for maize and sugarcane ATJ routes. Under historical deforestation rates, the LUC GHG emissions are higher. Bio-SAF can be beneficial to reduce GHG emissions if effective land conservation policies are implemented. Therefore, large-scale bio-SAF production from sugar crops in Brazil may play an important role in the decarbonisation of the aviation sector if coupled with successful strategies to control deforestation. Additionally, when imposing bio-SAF demand, other biofuels demand reduces under the model optimal solution due to land restrictions.
LMS Adaptive FIR Filter-Predictive Controller Based On D-Q Control Theory for Grid-Connected Solar PV System
Authors: Karchi Nalini , Kulkarni Deepak
Published: December 2022

A Least Mean Square (LMS) adaptive Finite Impulse Response (FIR) filter-predictive controller is presented for the control of a grid-connected solar PV energy system. The objective of the work is to reduce total harmonic distortion (THD) in the grid and load current. It follows the systematic development and analysis of the implementation of an adaptive LMS control based on the direct-quadrature control theory. The analysis is done for the proposed adaptive control technique for grid-connected solar photovoltaic systems under the variation of solar irradiation and load. In this proposed work, the reference current is estimated by developing the LMS control technique. The proposed system is modeled in d-q frame form and simulated on the MATLAB Simulink platform. Developing an LMS control algorithm using the p-q theory reduces computational hard work. The reduction in load current harmonics is improved. The simulation results are used to discuss the convergence rate, harmonics reduction, and advantages of the adaptive LMS algorithm d-q control theory.
Hybrid Electric Vehicle Design and Simulation Performance Using Isolated DC/DC Converter Based MFO Algorithm
Authors: Sekhar V , Nithyamala K , Renuka K , Murali M
Published: December 2022

The accuracy and effectiveness of the vehicle’s motor, DC-DC converter, controller, and electrical system are crucial for Hybrid Electric Vehicles (HEV). The study is given with a DC-DC converter architecture and motor based on the MFO control algorithm for smooth driving and quick charging of hybrid electric vehicles. The front-end AC-DC converter’s output is translated by the suggested DC-DC converter architecture, which then provides a controlled supply to the EV propulsion battery. The suggested system consists of a drive train model created in MATLAB using the SIMULINK tool, a motor drive, a DC-DC converter, an inverter, and a drive train. A Simulink model with motor drive model was constructed and successfully simulated in order to operate and evaluate the performance of hybrid electric vehicles utilizing an MFO control method. The simulation findings are examined its performance of EV system and results clearly stated the hybrid car’s fuel efficiency advantages over the conventional vehicle model.
Magnification of energy transmission ratio using miniature cycloidal gear box for humanoids
Authors: Chavan Umesh , Joshi Atharv , Kolambe Yash , Gwalani Harsh , Chaudhari Harish , Khalate Aniket , Hujare Pravin
Published: December 2022

Design challenges arise in applications like humanoids where high torque is required to move and self-balance the bot. Present research focuses on development of a cycloidal gearbox for humanoid shoulder joints. Light weight gear box assembly was designed with mass of 360g. Structural design and analysis of cycloidal gearbox is carried out. A 3D printed prototype is developed to validate motion analysis. It was actuated by NEMA 17 step motor (0.45 N-m) which is controlled by A4988 motor driver module on the Arduino platform. The speed reduction ratio is achieved 20:1 in a very small space of 60 x 60 x 20mm. Motor torque 0.45Nm is magnified up to 8.82Nm. Result shows proposed cycloidal gearbox satisfies requirement of humanoid shoulder joints such as high torque, light weight and compact assembly. Additional features noticed are back drivable, vibration and noise free transmission which are highly desirable for humanoid shoulder joints.
Processing and tribological behaviour of carbon fiber reinforced polylactic acid composites
Authors: Suresha B. , Hanamasagar Vikas , Anand A.
Published: December 2022

Thermoplastic composites are acquiring more importance in various tribological applications due to their self-lubricity, low melting, and ease of fabrication. In this research article, processing via fused deposition modelling and dry sliding wear behaviour of neat and short carbon fiber reinforced polylactic acid composites have been investigated. A series of wear tests using a pin-on-disc wear apparatus was carried out by varying tribo-parameters namely applied load (10, 20, and 30 N), sliding velocity (0.5, 1.0, and 1.5 m/s), and sliding distance (1000, 2000, and 3000 m) following the response surface methodology. Analysis of variance was performed for optimizing the operating parameters with respect to minimum specific wear rate. The experimental outcomes showed decrease in specific wear rate of polylactic acid composites by 70 % in comparison to neat polylactic acid, due to reinforcement of short carbon fibers. Worn surface morphology of neat polylactic acid and carbon fiber reinforced polylactic acid show fine groves in the sliding direction, thinning of fibers and net work of microcracks and few pull-out of fibres from the matrix material.
Study of LCF behaviour and life estimation based on modified SWT model and enhanced strain energy density of Ti–6Al–4V ELI
Authors: Ikhar T D , Chavan U
Published: December 2022

Among various types of Titanium alloy, Ti–6Al–4V ELI is the most extensively used alloy. This particular type of alloy is officially termed as Bio-material owing to its high strength, bio-compatibility, low density and good formability characteristics of titanium. Hence, it becomes necessary to evaluate its fatigue properties and low cycle fatigue behaviour for the bio-medical applications such as implants which is subjected to cyclic loading because of various physical movements performed by individual like walking, jumping or running. In this study, completely reversible strain controlled fatigue tests were carried out for various strain amplitudes at an ambient environment. The experimental data was evaluated to describe the cyclic deformation behaviour, Strain-Life plot, maximum stress variation, cyclic softening behaviour and massing behaviour. Finally, two different methods are proposed to estimate the fatigue life of Ti–6Al–4V ELI on the basis of experimental data. First is SWT model which was originally proposed by Swift, Watson and Topper to account the mean stress effect on Fatigue life is further modified in this study by replacing stress amplitude determined at the half-life with the stress amplitude determined at the first cycle. And second is estimation of Fatigue life on the basis of the Accumulated Plastic Strain Energy Density (PSED). The fatigue life estimation carried out based on above two approaches demonstrated very well agreement with experimental life.
Oxygen transport in the low–Pt catalyst layer of a PEM fuel cell: Impedance spectroscopy study
Authors: Reshetenko Tatyana , Kulikovsky Andrei
Published: December 2022

A model for PEM fuel cell impedance taking into account the pore size distribution (PSD) in the cathode catalyst layer is developed. Experimental PSD is approximated by pores of three sizes (small, medium and large) and in each kind of pores, the oxygen diffusion coefficient is allowed to have a separate value. The model is fitted to experimental impedance spectra of a low–Pt PEM fuel cell. The oxygen diffusivities of small and medium pores exhibit rapid growth with the cell current density, while in large pores, this parameter remains nearly constant. We show that oxygen reduction occurs mainly in the small and medium pores, leaving the large pores for mass transport only. This effect explains the discrepancy between small effective oxygen diffusivity of PEMFC catalyst layer measured in situ in operating cells by limiting current method, and much larger value of this parameter determined from ex situ experiments using Loschmidt cell.