bluuebunny/crossref_metadata_2025 huggingface dataset:
An improved wireless power transmission system for micro unmanned aerial vehicles
Authors: Liu Shunyu , Guo Yuehao , Su Ting , Wu Haotian , Xing Genghao , Yang Yongqin
Published: July 2024

Due to its limited load capacity, the piggybacking of wireless charging systems for micro unmanned aerial vehicles has become a challenging task in the design of micro unmanned aerial vehicles. Therefore, this paper proposes an improved lightweight design method for micro unmanned aerial vehicles to carry a wireless charging system. The improved system uses an inductor–capacitor–capacitor‐parallel (LCC‐P) topology compensation network instead of a bilateral inductor–capacitor–capacitor (LCC) topology compensation network to achieve constant current charging (CC) and constant voltage charging (CV). Then the adaptive frequency conversion control is used to realize the automatic conversion from CC charging to CV charging during the charging process. Compared with the traditional wireless charging system based on a direct current‐direct current converter (DC‐DC converter) to achieve CC charging and CV charging, this improved system reduces the total weight of the receiving end of the wireless charging system based on ensuring the charging efficiency, which meets the demand of wireless charging systems carried by micro drone aircraft. The test results of the constructed physical system coincide with the simulation design results, and the total weight of the receiving end is only 8 g, which verifies the correctness and effectiveness of the improved design scheme.
Data‐driven target localization using adaptive radar processing and convolutional neural networks
Authors: Venkatasubramanian Shyam , Gogineni Sandeep , Kang Bosung , Pezeshki Ali , Rangaswamy Muralidhar , Tarokh Vahid
Published: July 2024

Leveraging the advanced functionalities of modern radio frequency (RF) modeling and simulation tools, specifically designed for adaptive radar processing applications, this paper presents a data‐driven approach to improve accuracy in radar target localization post adaptive radar detection. To this end, we generate a large number of radar returns by randomly placing targets of variable strengths in a predefined area, using RFView®, a high‐fidelity, site‐specific, RF modeling & simulation tool. We produce heatmap tensors from the radar returns, in range, azimuth [and Doppler], of the normalized adaptive matched filter (NAMF) test statistic. We then train a regression convolutional neural network (CNN) to estimate target locations from these heatmap tensors, and we compare the target localization accuracy of this approach with that of peak‐finding and local search methods. This empirical study shows that our regression CNN achieves a considerable improvement in target location estimation accuracy. The regression CNN offers significant gains and reasonable accuracy even at signal‐to‐clutter‐plus‐noise ratio (SCNR) regimes that are close to the breakdown threshold SCNR of the NAMF. We also study the robustness of our trained CNN to mismatches in the radar data, where the CNN is tested on heatmap tensors collected from areas that it was not trained on. We show that our CNN can be made robust to mismatches in the radar data through few‐shot learning, using a relatively small number of new training samples.
Numerical method for determining pressure distribution in tube cross-flow heat exchangers
Authors: Węglarz Katarzyna , Taler Dawid , Taler Jan , Marcinkowski Mateusz
Published: July 2024

This paper presents a numerical method for determining the pressure distribution along the fluid flow path in a cross-current hightemperature heat exchanger. The pressure drop across the superheater was determined using the momentum conservation equation, which was solved by the finite difference method. Local pressure losses at tube elbows were also taken into account. A new formula for calculating friction factor on rough tubes' inner surface is proposed. A straightforward model for the friction factor in tubes with a rough inner surface for Reynolds numbers in the interval 3000 - 108 has been proposed. The pressure distribution in the last stage of the live steam superheater in a 900 MWe supercritical boiler was calculated.
Tangential velocity and water vortex structure behaviour based on cylindrical-shaped basin’s design parameters for gravitational vortex power plants
Authors: Teber Ahmet
Published: July 2024

The gravitational water vortex power plants (GWVPPs) have established in hydropower systems as a capable approach, generating micro-scale environment friendly electricity. In this system, energy is produced as a result of the interaction of water coming from an inlet canal with the turbine by creating a vortex in circular/conical-shaped structures. This interaction is based on an assumption that the water flow rate in a basin coincides with the tangential velocity on the turbine propeller. In this case, it is essential to investigate numerous geometric design parameters of the cylinder basin and their effects on vortex formation with the help of Computational Fluid Dynamics (CFD). Here, based on the CFD principles, the behaviour of various geometrical parameters on the vortex and tangential velocities in the basin are investigated separately with the help of Ansys Fluent, without using any turbine propeller. For a certain inlet flow velocity and head, different tunable geometric parameters for the gravitational water vortex plant with a cylindrical basin are inlet canal length, basin diameter, basin height and outlet diameter, respectively. The objective is to achieve an improved design configuration concerning factors such as tangential velocity, vortex arrangement, and the optimal placement of turbine propellers within this vortex.
Magnetically controlled systems for CO2 absorption
Authors: Mateev Valentin , Marinova Iliana
Published: July 2024

In this paper is presented a conceptual model of magnetically controlled system for CO2 absorption. A design of magnetic air contactor is considered and internal magnetic field in its channels is modelled. It is a closed domain contactor design with controllable internal thermodynamic conditions, additionally influenced by magnetic field. Considered design is providing huge specific surface for dynamic interaction with the processed airflow. Results on magnetic field distribution inside air channels are calculated in order to estimate field homogeneity and force directions on used particles.
Mouvements répétitifs : entre neurologie et comportement
Authors: Arpaillange Colette , Mège Catherine
Published: July 2024

Les mouvements répétitifs envahissants sont des mouvements isolés ou enchainés sous une forme fixe, sans rapport apparent avec le contexte d’émission. Les mouvements répétitifs peuvent être la manifestation d’une épilepsie partielle psychomotrice ou apparaître lors d’un trouble du comportement.

Certaines de ces affections connaissent des prédispositions génétiques assez nettes (gobage de mouches du CKC, poursuite d’ombres chez les Border Collie, tournis chez le Bull terrier).

Le diagnostic nécessite un examen neurologique attentif et une étude comportementale.

Des examens d’imagerie peuvent être indiqués.
Le traitement dépend de l’orientation diagnostique. Il repose le plus souvent sur une association de molécules. La thérapie comportementale est toujours utile.
Das Notvertretungsrecht des Ehegatten in Gesundheitsangelegenheiten
Authors: Dornis Christian
Published: July 2024

Am 01.01.2023 trat der im Rahmen der Betreuungsrechtsreform geschaffene § 1358 BGB in Kraft. Er regelt das Notvertretungsrecht des Ehegatten in Gesundheitsangelegenheiten und stellt eine bedeutende Neuerung im deutschen Rechtssystem dar. Die Neuregelung ermöglicht es einem Ehegatten, medizinische Entscheidungen für den anderen Ehegatten zu treffen, wenn dieser dazu nicht in der Lage ist. Die Neuregelung zielt darauf ab, das Betreuungswesen zu entlasten und schnelle Entscheidungen in akuten Situationen zu ermöglichen. Die Vertretungsmacht des Ehegatten erstreckt sich auf Gesundheitsfragen sowie darauf bezogene Verträge und finanzielle Angelegenheiten. Die Ausgestaltung der Reglung hat Kritik hervorgerufen, die sich insbesondere an der als zu bürokratisch empfundenen Regelung der Notwendigkeit der Ausstellung einer ärztlichen Bescheinigung entzündet. Trotzdem ist die Neuregelung insgesamt entlastend für Angehörige und Justiz.
Praxis der onkologischen Selentherapie
Authors: Stoll Günther
Published: July 2024

Obwohl Selenpräparate bereits seit vielen Jahren als Nahrungsergänzungsmittel
sowie auch als Arzneimittel zur Verfügung stehen, gibt es nach wie vor viele
Unsicherheiten und offene Fragen zu verschiedenen Anwendungsdetails. Macht eine
Selengabe im Rahmen einer onkologischen Therapie Sinn und welche Dosierungen
sind dazu notwendig? Welche Selensubstanzen gibt es? Und können Selenpräparate
auf Kassenrezept verordnet werden? Der Beitrag beantwortet im Sinne eines
Therapiemanuals die häufigsten Fragen, die im Rahmen der Therapieberatung immer
wieder auftauchen, und verweist für detailliertere Informationen auf weitere
Quellen.
Epilepsie-Update
Authors: Winter Yaroslav , Ellwardt Erik
Published: July 2024

Die letzten Jahre waren geprägt von der Etablierung neuer, innovativer Diagnose- und Therapieverfahren im Bereich der Epileptologie. Es sind beispielsweise Systeme zur Ultra-Langzeit-EEG-Registrierung verfügbar. Die Frühtherapie einer refraktären Epilepsie wird zunehmend durch die Entwicklung neuer Therapiemethoden verbessert. Neurostimulationsverfahren werden weiterentwickelt und neue Technologien wurden eingeführt. Vielversprechend sind auch die synergistischen Effekte der Neurostimulation in Kombination mit bestimmten Wirkmechanismen anfallsunterdrückender Medikamente im Rahmen der Neuromodulation. Dieser Überblick beleuchtet all diese Entwicklungen der letzten anderthalb Jahre.
Neue therapeutische Entwicklungen der Multiplen Sklerose
Authors: Dann Justus , Haghikia Aiden , Gold Ralf , Faissner Simon
Published: July 2024

Die Behandlungsmöglichkeiten der Multiplen Sklerose (MS) haben sich in den letzten 20 Jahren durch ein breites Arsenal von verlaufsmodifizierenden Immuntherapien massiv verbessert. Dies führt zunehmend zu einer Diskussion über eine Linksverschiebung des Therapiestarts bei Betroffenen mit einem ersten demyelinisierenden Herd im Rahmen eines radiologisch-isolierten Syndroms. Neue therapeutische Entwicklungen betreffen die Phase-III-Studienprogramme zu Inhibitoren der Bruton-Tyrosinkinase, die potenziell B-Zellen und myeloide Zellen im ZNS adressieren und deren weitere Ergebnisse im Jahr 2024 erwartet werden. Anti-CD20 gerichtete Antikörper erfahren u. a. durch die Entwicklung von „brain shuttles“ zur besseren Penetration des ZNS eine Evolution. Die Hemmung des kostimulatorischen CD40-Liganden Signalwegs wird mit Frexalimab in kürzlich begonnen Phase-III-Programmen untersucht. Außerdem werden zellbasierte Technologien aus der Onkologie mit der autologen hämatopoetischen Stammzelltransplantation (aHSCT) und innovativen Verfahren wie der chimeren Antigen-Rezeptor-(CAR-) T-Zelltherapie vorangetrieben. Diese Ansätze haben das Potenzial, bei therapierefraktären Verläufen unter hocheffektiven Therapien eingesetzt zu werden, befinden sich jedoch in einem sehr frühen Entwicklungsstadium. In dieser Übersichtsarbeit werden wir den aktuellen Stand der MS Therapiepipeline erörtern.
Interobserver Agreement of visual and semi-quantitative methods in 99mTc-Methoxy-Isobuty-Isonitrile (MIBI) imaging for risk stratification of hypofunctional thyroid nodules
Authors: Schenke Simone Agnes , Kreissl Michael C , Vogel Jana , Haghghi Sarvar , Herkula Corinna , Petersen Manuela , Seifert Philipp , Wallbaum Thekla
Published: July 2024

Aim 99mTc-Methoxy-Isobuty-Isonitrile (MIBI) imaging is used for risk stratifications of hypofunctioning thyroid nodules (TNs). MIBI uptake in the nodular tissue is compared to the uptake in the paranodular thyroid tissue. MIBI imaging may be interpreted visually and/or semi-quantitatively. This study aimed to evaluate the interobserver agreement (IOA) of different methods of interpreting MIBI imaging (visual and semi-quantitative approaches).

Methods MIBI imaging data from 2018 to 2020 were collected. Four readers with varying work experience prospectively evaluated MIBI images (planar, SPECT/CT) visually and semi-quantitatively (Wash-Out Index (WOI)). After identifying the nodules on 99mTc-pertechnetate scintigram, the readers evaluated MIBI imaging data by using early, late, early-to-late, and SPECT late acquisitions. Region of interests (ROIs) were defined for semi-quantitative analysis and average counts were calculated using the WOI formula (by Campenni et al.) 1
2. IOA was assessed using Fleiss Kappa, Pearson correlation and Analysis of Variance (ANOVA).

Results 23 patients with hypofunctioning nodules were included. Kappa analysis revealed an IOA of 0.57 for all readers for early imaging (moderate agreement); perfect matches were found in 57%. For late imaging, the IOA was 0.48 (moderate) for all, with perfect matches in 48%. The visual pattern (early-to-late) exhibited an IOA of 0.45 for all, with perfect matches in 57%. SPECT/CT evaluation showed an overall IOA of 0.44, with perfect matches in 48%. The semi-quantitative approach WOI yielded an overall result of 0.64 (good agreement) and perfect matches in 91%.

Conclusion The IOA for WOI was higher than for visual methods. The WOI is independent of the reader’s experience level. Visual analysis requires a certain level of experience from the reader.
Implementierung der Tabakentwöhnung in den Workflow des Lungenkrebsscreenings in Deutschland
Authors: Rupp Alexander , Sohrab Sebastian , Pankow Wulf , Raspe Matthias , Kotz Daniel , Rustler Christa , Blum Torsten Gerriet , Bauer Torsten , Windisch Wolfram , Andreas Stefan ,   Unterstützt von medizinischen Fachgesellschaften und Organisationen: Deutsche Gesellschaft für Innere Medizin e. V. (DGIM),   Deutsche Röntgengesellschaft e. V. (DRG),   Deutsche Gesellschaft für Thoraxchirurgie e. V. (DGT),   Deutsche Krebsgesellschaft e. V. (DKG),   Deutsche Gesellschaft für Arbeitsmedizin und Umweltmedizin e. V. (DGAUM),   Bundesverband der Pneumologie, Schlaf- und Beatmungsmedizin e. V. (BdP),   Deutsches Netz rauchfreier Krankenhäuser und Gesundheitseinrichtungen gem. e. V. (DNRfK)
Published: July 2024

Sowohl die Tabakentwöhnung als auch ein Low-dose-CT-Screening bei Risikopersonen senken die lungenkrebsspezifische Mortalität und die Gesamtmortalität. Im Rahmen eines nationalen Screeningprogramms zur Früherkennung von Lungenkrebs muss die Tabakentwöhnung obligater Bestandteil der Beratung der Teilnehmenden sein. Hierdurch wird auch die Kosten-Nutzen-Effektivität des Screeningprogramms gesteigert. Im Rahmen des Erstgesprächs müssen Teilnehmenden des Screeningprogramms in Form einer Minimalintervention evidenzbasierte Maßnahmen zur Tabakentwöhnung angeboten werden. Bei nicht gewünschter Tabakentwöhnung müssen Teilnehmende des Screeningprogramms aktiv widersprechen (Opt-out-Regelung). Die Kosten für die Tabakentwöhnung inklusive der Kosten für eine entzugshemmende Medikation sind durch die Gesetzliche Krankenversicherung vollständig zu übernehmen.
Comparison of Effects of Acellular Dermal Matrix and Latissimus Dorsi Muscle Flap on Radiation-induced Peri-implant Capsular Contracture in a Rabbit Model
Authors: Jang Suk Yoon , Ahn Il Young , Bae Tae Hui , Kang Shin Hyuk , Woo Soo Hyun , Kim Woo Ju , Kim Mi Kyung , Sutthiwanjampa Chanutchamon , Kim Han Koo
Published: July 2024

Background Capsular contracture of breast implants is a major complication in breast surgery. Clinically, covering a breast implant with acellular dermal matrix (ADM) or autologous tissue is considered to be the most effective technique to prevent capsular contracture. This study was designed to compare the protective effects of ADM and latissimus dorsi (LD) muscle flap placement on capsular contracture by increasing the rate of capsular contracture through controlled radiation exposure in a rabbit model.

Methods Twenty New Zealand white rabbits were divided into three groups. After the implant was placed beneath the pectoralis major muscle, the lateral third of the implant was left exposed in the control group (n = 6). In the ADM group (n = 7), the exposed implant was covered with AlloDerm. In the LD flap group (n = 7), the exposed implant was covered with a pedicled LD muscle flap. All groups were irradiated 3 weeks after implant insertion. After 6 months, peri-implant tissues were harvested and analyzed.

Results ADM showed markedly lower myofibroblast activity than the LD flap. However, transforming growth factor-β1 levels and the activity of collagen types I and III produced in fibroblasts were significantly lower in the ADM group than in the LD flap group.

Conclusion Based on the findings of our rabbit experiments, ADM is expected to have a comparative advantage in reducing the risk of capsular contracture compared to the LD flap.
Prevalence of Osteoporosis and Sarcopenia in Middle-Aged Subjects with Low Back Pain
Authors: Narayan Shamrendra , Pratap Rishabh , Raj Gaurav , Chauhan Abhishek , Kumar Tushant , Singh Neha , Singh Ajai Kumar , Gupta Nikhil
Published: July 2024

Objective The genesis of both osteoporosis and sarcopenia is multifactorial, complicated, and interrelated. The present study has been undertaken to analyze the prevalence of low bone mineral density (BMD) and the pattern of imaging markers of sarcopenia (paraspinal skeletal muscle area [SMA] and skeletal muscle index [SMI] with respect to clinicodemographic profile in middle-aged patients (30–45 years) undergoing evaluation for low back pain (LBP).

Materials and Methods Magnetic resonance imaging (MRI) of the lumbosacral spine and/or sacroiliac joints was done on 3T MRI. BMD of the lumbar spine (L1 to L4) was assessed using a dual-energy X-ray absorptiometry scan. SMA was calculated by measuring the cross-sectional area of paraspinal muscles (bilateral psoas, erector spinae, and multifidus), and SMI was calculated by dividing SMA by height2.

Results The prevalence of osteoporosis was 12.1% in patients of age 30 to 45 years presenting with LBP. Both osteoporosis and paraspinal muscle mass were statistically associated with the duration of symptoms (p-value <0.05). No statistically significant difference was observed in different MRI findings, that is, normal, inflammatory, infective, and degenerative etiology.

Conclusion Low BMD and loss of muscle mass in cases with LBP are more related to duration of disease rather than etiology or gender in middle-aged subjects. Early intervention to manage LBP may prevent progression to osteoporosis and sarcopenia in young adults.
Single-Portal Arthroscopy Improves the Assessment of Radial-sided Disorders of the Wrist
Authors: Luchetti Riccardo , Montanari Sara , Marcovici Lucian Lior , Cozzolino Roberto , Kakar Sanjeev , Atzei Andrea
Published: July 2024

Purpose This study aimed to describe the technique, indications, and advantages of the single-portal arthroscopic approach for the diagnosis and staging of chronic radial-sided disorders, including scapholunate interosseous ligament (SLIL) tear, scapholunate advanced collapse (SLAC) and scaphoid nonunion advanced collapse (SNAC) deformities.

Methods The single portal technique was used in 138 patients affected by suspected SLIL lesions, SLAC and SNAC wrist injuries with positive clinical symptoms and inconclusive imaging (X-ray and MRI). It was used to grade the nature of the SLIL lesion and the extension of the osteochondral damage in the SLAC and SNAC wrist deformity to guide appropriate treatment.

Results Patients were divided into group 1 (SLIL: 45 cases), group 2a (SLAC: 65 cases), and group 2b (SNAC: 28 cases). In group 1, stage 4 SLIL lesions were confirmed in 36 cases and 9 were assessed as SLAC wrist deformity. In group 2a, single-portal arthroscopy confirmed the preoperative diagnosis in 74% of cases. In the remaining 26% of patients, arthroscopy modified the preoperative diagnosis: 1 case of SLAC 1 resulted in SLAC 2, 14 cases of SLAC 2 resulted in SLAC 3, 1 case of SLAC 3 resulted in SLAC 2. A case of SLAC 2 turned out to be an SLIL lesion stage 4. In group 2b, single-portal arthroscopy confirmed the preoperative diagnosis in 86% of cases. In the remaining 14% (4 cases), it modified the preoperative diagnosis: 1 of SNAC 1 resulted in SNAC 2 and the other in SNAC 3, 1 case of SNAC 2 turned out to be an SNAC 3, and 1 case of SNAC 3 resulted in SNAC 4.

Conclusion Single-portal wrist arthroscopy modified the preoperative diagnosis of wrist pathology in 42 patients over 138 cases. The use of single-portal wrist arthroscopy should be considered in the evaluation of the radiocarpal and midcarpal joints to allow accurate visualization of the joint surfaces for surgeon and patient planning.

Type of Study/Level of Evidence Observational study level of evidence IV.
Frailty is Superior to Age at Predicting Extended Length of Stay and Immediate Postoperative Complications Following Total Wrist Arthrodesis
Authors: Koltenyuk Victor , Merckling Matthew , Li Michael , Jarin Ian , Konigsberg Matthew
Published: July 2024

Hypothesis The modified five-factor frailty index (mFI-5) is a better predictor than age alone of increased risk of extended length of stay (LOS) and postoperative complications in patients undergoing total wrist arthrodesis (TWA).

Methods The National Inpatient Sample database was queried for patients undergoing elective TWA. Patients were identified using the International Classification of Diseases, 10th Revision procedure codes, excluding nonelective cases, hardware removal, and patients with cerebral palsy or seizure disorders. Frailty was assessed by identifying the variables used in the mFI-5 and patients were categorized as nonfrail (mFI-5 = 0), prefrail (mFI-5 = 1), and frail (mFI-5 ≥ 2). Outcomes assessed included LOS and immediate postoperative complications such as nausea and vomiting requiring admission, acute kidney injury, postoperative hypotension, postoperative hypothyroidism, and urinary tract infection. Logistic regression was used to analyze the association between frailty status and both extended LOS and immediate postoperative complications.

Results Between 2015 and 2019, 685 patients underwent TWA, with 49.6% not frail, 33.5% prefrail, and 16.7% frail. Prefrail and frail patients were at increased risk of undergoing extended LOS (OR 2.182, p = 0.001; OR 2.312, p = 0.002, respectively). Age over 65 (OR 1.995, p < 0.001) and female sex (OR 1.605, p = 0.029) were also independent risk factors. Frail patients were found to have an increased likelihood of acquiring any postoperative complication (OR 3.865, p < 0.001), while elderly age was not a significant risk factor (OR 1.361, p = 0.298). Using receiver operating characteristic (ROC) curve analysis, the mFI-5 demonstrated superior discriminatory ability compared with age for extended LOS (Area under the curve (AUC) 0.729 vs. 0.542) and postoperative complications (AUC 0.712 vs. 0.673).

Conclusion Our study demonstrates that both elderly age and frailty are independent predictors of extended hospitalization following TWA, while frailty but not age, is a significant predictor of immediate postoperative complications. To our knowledge, our study is the first to report an association between frailty status and immediate postoperative complications following TWA. Incorporating a preoperative frailty screening can allow for more open and informed preoperative discussion about surgical risk for elective procedures such as TWA, as well as allow for enhanced postoperative planning.
The Fatty Dilemma: A Rare Instance of Extra- and Intravascular Lipoma of the Brachiocephalic Vein
Authors: Hiregouja Eranna Roja , Pokanati Suhasini Devi , Rajkumar B.
Published: July 2024

Oftentimes, incidental findings are made on routine diagnostic imaging. An intra- and extravascular lipoma is one example of an important incidental finding. Intravascular lipomas are rare benign vascular tumors that are typically asymptomatic. They are most commonly found in the inferior vena cava but have also been recorded in the superior vena cava, brachiocephalic vein, subclavian vein, internal jugular vein, external jugular vein, and common femoral vein. Here, we presented the case of a 64-year-old female patient with an incidentally discovered intra- and extravascular lipoma affecting the right subclavian and brachiocephalic veins. While benign, intravascular lipoma on imaging can resemble a malignant tumor such as leiomyosarcoma or thrombus. As a result, appropriate identification and classification of this imaging finding is crucial for avoiding an exorbitant and futile workup.
Looking for a way out: The dynamics of slum life, poverty, and everyday resistance in Katherine Boo’s Behind the Beautiful Forevers
Authors: Soliman Nada
Published: July 2024

This article looks into the implications of urban informality in Katherine Boo’s Behind the Beautiful Forevers: Life, Death and Hope in a Mumbai Slum (2012) as represented in slum life and urban poverty. It aims to investigate the impact of urban poverty on the everyday practices of slum dwellers and their endeavors to escape the trap of poverty in an attempt to highlight the human dimension of the slum. The article seeks to unravel multi-layers of the interaction between people and poverty and the differing models of resistance to poverty and social exclusion depicted in the nonfiction narrative. The article examines slum life from a descriptive sociological perspective with a detailed description of how people survive in poverty. The study of the culture of slums entails an analysis of the survival techniques and everyday practices of slum dwellers, the relations and patterns of behavior among the different categories of people inhabiting a slum, and the outcomes of the interplay between place, culture, and power relations in such communities. This is implemented through an eclectic sociological approach that comprises theories of space, culture, and resistance as proposed by James Scott, Theodore W. Schultz, and Henri Lefebvre.
Automated Bayesian high-throughput estimation of plasma temperature and density from emission spectroscopy
Authors: Oliver Todd A. , Michoski Craig , Langendorf Samuel , LaJoie Andrew
Published: July 2024

This paper introduces a novel approach for automated high-throughput estimation of plasma temperature and density using atomic emission spectroscopy, integrating Bayesian inference with sophisticated physical models. We provide an in-depth examination of Bayesian methods applied to the complexities of plasma diagnostics, supported by a robust framework of physical and measurement models. Our methodology is demonstrated using experimental observations in the field of magneto-inertial fusion, focusing on individual and sequential shot analyses of the Plasma Liner Experiment at LANL. The results demonstrate the effectiveness of our approach in enhancing the accuracy and reliability of plasma parameter estimation and in using the analysis to reveal the deep hidden structure in the data. This study not only offers a new perspective of plasma analysis but also paves the way for further research and applications in nuclear instrumentation and related domains.
Quantifying macrostructures in viscoelastic sub-diffusive flows
Authors: Chauhan T. , Kalyanaraman K. , Sircar S.
Published: July 2024

We present a theory to quantify the formation of spatiotemporal macrostructures (or the non-homogeneous regions of high viscosity at moderate to high fluid inertia) for viscoelastic sub-diffusive flows, by introducing a mathematically consistent decomposition of the polymer conformation tensor, into the so-called structure tensor. Our approach bypasses an inherent problem in the standard arithmetic decomposition, namely, the fluctuating conformation tensor fields may not be positive definite and hence, do not retain their physical meaning. Using well-established results in matrix analysis, the space of positive definite matrices is transformed into a Riemannian manifold by defining and constructing a geodesic via the inner product on its tangent space. This geodesic is utilized to define three scalar invariants of the structure tensor, which do not suffer from the caveats of the regular invariants (such as trace and determinant) of the polymer conformation tensor. First, we consider the problem of formulating perturbative expansions of the structure tensor using the geodesic, which is consistent with the Riemannian manifold geometry. A constraint on the maximum time, during which the evolution of the perturbative solution can be well approximated by linear theory along the Euclidean manifold, is found. A comparison between the linear and the nonlinear dynamics, identifies the role of nonlinearities in initiating the symmetry breaking of the flow variables about the centerline. Finally, fully nonlinear simulations of the viscoelastic sub-diffusive channel flows, underscore the advantage of using these invariants in effectively quantifying the macrostructures.
Relaxation dynamics of higher excited states of perylene-substituted perylene bisimide derivatives
Authors: Kobayashi Yoichi , Fukuda Daiki , Okayasu Yoshinori , Nagai Yuki
Published: July 2024

Stepwise two-photon absorption processes have received considerable attention, especially in photocatalysis, due to their relatively lower power threshold, characteristic spatial selectivity, amplification of chemical reactions, and so on. Meanwhile, studies on the relaxation dynamics of higher excited states in condensed systems have been limited for several molecular systems due to the short-lived nature of these states. In this study, we synthesized perylene-substituted perylene bisimide (PBI) and its derivate as model compounds and investigated their excited-state dynamics, including higher excited states, using pump–repump–probe spectroscopy. We revealed that these molecules form charge-transfer (CT) states instantaneously after the excitation, regardless of whether it is the perylene moiety or the PBI moiety that is excited. The lifetime of the CT state was shorter when the distance between the donor (perylene) and the acceptor (PBI) was shorter. Moreover, we also revealed that a higher-lying CT state generated by the stepwise excitation of the CT state using a 740-nm pulse induced Stark effect to the neighboring perylene moiety. The Stark effect not only gives more detailed information about the CT state, but also presents the possibility of new photofunctions, such as instantaneous modulation of the electronic state to achieve optimal electronic properties. These insights contribute to understanding advanced photochemical reactions and would be important for exploring photocatalytic reactions involving higher excited states.
Catalyst–sulfur bidirectional stimulation to accelerate redox kinetics for high-performance cryogenic lithium-sulfur batteries
Authors: Zhou Yang , Qian Siyi , Zhou Jinqiu , Zhang Lifang , Cheng Yu , Liu Jie , Yan Chenglin , Qian Tao
Published: July 2024

The development of cryogenic lithium-sulfur batteries (LSBs) suffers from the sluggish reaction kinetics and the shuttle effect of polysulfide. In order to accelerate the redox process and improve the utilization rate of elemental sulfur at the low temperature, we first propose catalyst–sulfur bidirectional stimulation to accelerate redox kinetics for high-performance cryogenic LSBs. Theoretical calculation and experimental results suggest that the selenium-doped MoS2 (SeDMoS2) catalyst can not only effectively capture and anchor polysulfide but also can interact with the sulfur species to stimulate each other, thus boosting the low-temperature kinetics and optimizing the cryogenic capacity. Quite impressively, with the assistance of the bidirectional stimulation between the SeDMoS2 catalyst and sulfur, the LSB can deliver a high initial capacity of 732 mAh g−1, and only ∼0.3% of the capacity is attenuated per cycle during 100 cycles at the low temperature of −40 °C. This strategy throws light on the further development of high-capacity cryogenic LSBs and points the way to explore other low-temperature metal batteries.
Development of ultra-short pulse reflectometry on the Experimental Advanced Superconducting Tokamak (EAST)
Authors: Li Xiaoliang , Chen Ran , Xu Guosheng , Domier Calvin , Liu Xianzi , Zhang Yiwei , Zhou Tianfu , Zhu Yilun , Yu Guanying , Qiu Shasha , Yu Hai , Luhmann Neville C.
Published: July 2024

Microwave reflectometry is an invaluable diagnostic tool for measuring electron density profiles in large fusion devices. Density fluctuations near the plasma cutoff layer, particularly those that are time-varying on the timescale of the reflectometry measurement, can result in distortions in phase and/or amplitude of the reflected waveform, which present challenges to the accuracy of the reconstructed profile. The ultra-short pulse reflectometry (USPR) technique eliminates the time-varying issue in that reflectometry data are collected on a nanosecond timescale, essentially freezing the fluctuations in place. An X-mode dedicated 32-channel USPR system has been developed and installed on the EAST, covering the operation frequency range from 52 to 92 GHz. This system enables high-resolution density profile measurements in the plasma pedestal and scrape-off layer, with resolutions reaching 5 mm and 1 μs, respectively. Laboratory testing of the system performance has been conducted, demonstrating the potential of the USPR technique to provide accurate and high-temporal-resolution density profiles in challenging plasma environments.
Random close packing of semi-flexible polymers in two dimensions: Emergence of local and global order
Authors: Martínez-Fernández Daniel , Pedrosa Clara , Herranz Miguel , Foteinopoulou Katerina , Karayiannis Nikos Ch. , Laso Manuel
Published: July 2024

Through extensive Monte Carlo simulations, we systematically study the effect of chain stiffness on the packing ability of linear polymers composed of hard spheres in extremely confined monolayers, corresponding effectively to 2D films. First, we explore the limit of random close packing as a function of the equilibrium bending angle and then quantify the local and global order by the degree of crystallinity and the nematic or tetratic orientational order parameter, respectively. A multi-scale wealth of structural behavior is observed, which is inherently absent in the case of athermal individual monomers and is surprisingly richer than its 3D counterpart under bulk conditions. As a general trend, an isotropic to nematic transition is observed at sufficiently high surface coverages, which is followed by the establishment of the tetratic state, which in turn marks the onset of the random close packing. For chains with right-angle bonds, the incompatibility of the imposed bending angle with the neighbor geometry of the triangular crystal leads to a singular intra- and inter-polymer tiling pattern made of squares and triangles with optimal local filling at high surface concentrations. The present study could serve as a first step toward the design of hard colloidal polymers with a tunable structural behavior for 2D applications.
Diffusionless rotator–crystal transitions in colloidal truncated cubes
Authors: Sharma Abhishek Kumar , Escobedo Fernando A.
Published: July 2024

Upon osmotic compression, rotationally symmetric faceted colloidal particles can form translationally ordered, orientationally disordered rotator mesophases. This study explores the mechanism of rotator-to-crystal phase transitions where orientational order is gained in a translationally ordered phase, using rotator-phase forming truncated cubes as a testbed. Monte Carlo simulations were conducted for two selected truncations (s), one for s = 0.527 where the rotator and crystal lattices are dissimilar and one for s = 0.572 where the two phases have identical lattices. These differences set the stage for a qualitative difference in their rotator–crystal transitions, highlighting the effect of lattice distortion on phase transition kinetics. Our simulations reveal that significant lattice deviatoric effects could hinder the rotator-to-crystal transition and favor arrangements of lower packing fraction instead. Indeed, upon compression, it is found that for s = 0.527, the rotator phase does not spontaneously transition into the stable, densely packed crystal due to the high lattice strains involved but instead transitions into a metastable solid phase to be colloquially referred to as “orientational salt” for short, which has a similar lattice as the rotator phase and exhibits two distinct particle orientations having substitutional order, alternating regularly throughout the system. This study paves the way for further analysis of diffusionless transformations in nanoparticle systems and how lattice-distortion could influence crystallization kinetics.
Cyanonaphthalene and cyanonaphthyl radicals: Vibrational structures via computed negative ion photoelectron spectra and thermochemistry of 1- and 2-cyanonaphthalene
Authors: White Nolan J. , Vargas Lucia A. , Tunstall Wyatt W. , Koku Hannadige Abeysooriya Dushmantha N. , Gichuhi Wilson K.
Published: July 2024

A double harmonic oscillator model is applied to compute the negative ion photoelectron spectra (NIPES) of the 1- and 2-cyanonaphthalene (CNN) radical anions. The computed Franck–Condon factors utilize optimized structures and harmonic vibrational frequencies obtained using density functional theory with the B3LYP 6-311++G (2d,2p) basis set while considering the mode-mixing Duschinsky effects. To test the accuracy of our model, the NIPES of α and β naphthyl radical anions were computed, and a strong agreement between the slow electron velocity-map ion imaging spectra and the predicted spectra was found. The adiabatic electron affinities (EAs) of the ground singlet states (S0) in 1-CNN and 2-CNN are 0.856 and 0.798 eV, respectively. The origin of the lowest-lying triplet (T1) states in 1-CNN and 2-CNN is found to be 3.226 and 3.266 eV, resulting in singlet–triplet energy splittings (ΔEST) of 2.370 and 2.468 eV, respectively. Both the NIPES for electron detachment to the S0 and T1 states exhibit well-resolved vibrational features, allowing for the assignment of several vibrational fundamental frequencies. Following deprotonation, several isomers are formed, with the most stable deprotonated radical anions in 1-CNN and 2-CNN, corresponding to the removal of the most acidic proton, with EAs of 2.062 and 2.16 eV. The rich spectroscopic and thermochemical data obtained in the current study make the CNN radical anions and their deprotonated species interesting systems for investigation in gas-phase, negative-ion experiments.
Optical in situ deciphering of the surface reconstruction–assistant multielectron transfer event of single Co
3
O
4
nanoparticles
Authors: Jiang Bo , Li Haoran , Wang Wei , Wang Hui
Published: July 2024

Surface reconstruction determines the fate of catalytic sites on the near-surface during the oxygen evolution reaction. However, deciphering the conversion mechanism of various intermediate-states during surface reconstruction remains a challenge. Herein, we employed an optical imaging technique to draw the landscape of dynamic surface reconstruction on individual Co
3
O
4
nanoparticles. By regulating the surface states of Co
3
O
4
nanoparticles, we explored dynamic growth of the CoO
x
(OH)
y
sublayer on single Co
3
O
4
nanoparticles and directly identified the conversion between two dynamics. Rich oxygen vacancies induced more active sites on the surface and prolonged surface reconstruction, which enhanced electrochemical redox and oxygen evolution. These results were further verified by in situ electrochemical extinction spectroscopy of single Co
3
O
4
nanoparticles. We elucidate the heterogeneous evolution of surface reconstruction on individual Co
3
O
4
nanoparticles and present a unique perspective to understand the fate of catalytic species on the nanosurface, which is of enduring significance for investigating the heterogeneity of multielectron-transfer events.
Conformal sulfidation of HKUST-1 for constructing porous Cu2S/CuO octahedrons realizing highly sensitive non-enzymatic glucose detection
Authors: Liao Yanxin , Sun Shupei , Du Qian , Shi Nianfeng , Yin Guangfu , Huang Zhongbing , Liao Xiaoming
Published: July 2024

Metal–organic frameworks (MOFs) are believed to be promising precursors for constructing novel and efficient catalysts for glucose sensing. Herein, HKUST-1 precursors are first fabricated using a one-pot hydrothermal approach, and then HKUST-1 is converted into porous Cu2S/CuO octahedrons through conformal sulfidation with the help of OH− ions. The as-obtained Cu2S/CuO composite can provide rich electrochemical active sites and promoted electric transfer kinetics. Benefiting from these combined merits, the as-fabricated Cu2S/CuO composite is confirmed to be a high-performance catalyst, with high sensitivities of 8269.45 and 4140.82 μA mM−1cm−2 in the corresponding ranges of 0.05 ∼ 0.6 mM and 0.6 ∼ 1.2 mM, respectively. Moreover, the as-prepared electrode materials possess good anti-interference ability, reproducibility and long-term stability. This work opens up new avenues for the design and preparation of transition metal sulfide composites.
A stretchable and self-powered strain sensor with elastomeric electret
Authors: Li Yanyu , Li Yifan , Gu Haoyu , Zhai Chongpu , Song Siyang , Zhang Shuwen , Xu Minglong
Published: July 2024

Stretchable deformation sensors play an important role in the perception and autonomy of soft robots. While various sensors have been reported, the mechanical sensor with self-powered capability and stretchability to suit extreme environment is urgently required. In this study, a stretchable, self-powered, sensitivity adjustable, and long-term stability strain sensor based on the stretchable electret is researched for deformation monitoring. This stretchable and self-powered sensor is composed of the dielectric elastomer with designed elastic modulus gradient and the stretchable electret with elastomeric and Nano-particles. The electro-mechanical capability of this designed sensor is researched and optimized by multi-objective optimization approach. The sensor exhibits self-powered capability, stretchability (tensile strain from 0% to 20%), tunable sensitivity (optimized from 5.7 to 5.9 pC mm−1), and stability, where electromechanical performance remains stable after 8000 stretching cycles. The feasibility of its autonomous sensing which promotes a wide range of potential application in soft robotics is demonstrated. This elastic modulus gradient-induced and net charge design significantly broadened the potential applications with large deformation and low-attached stiffness.
Compression and encryption for remote sensing image based on PSO-BP and 2D-MCCM
Authors: Li Pei-zhen , Feng Xiu-fang , Zhou Shuang , Yan Peng-fei , Zhang Hao
Published: July 2024

In response to the large size of remote sensing images and the limitations of existing image compression and encryption algorithms, this paper proposes a novel compression and encryption algorithm. The proposed algorithm utilizes a new type of memristive chaotic mapping in combination with PSO-BP neural networks and multi-threaded parallelism. Specifically, the proposed novel two-dimensional memristive chaotic mapping involves a combination of new memristors based on HP memristors and Cubic chaotic mapping. Compared to existing chaotic systems, this method exhibits stronger randomness and hyperchaotic characteristics. Additionally, to improve the reconstruction accuracy of compressed images, a traditional BP neural network with an added hidden layer is combined with the PSO algorithm for image compression and reconstruction. Furthermore, to enhance the encryption efficiency of remote sensing images, a multi-threaded parallel encryption method is employed, enabling simultaneous permutation within and among threads. Experimental results demonstrate that the proposed algorithm achieves good compression reconstruction accuracy, excellent encryption performance, and resistance to attacks.
Helmert variance component estimation for mixed additive and multiplicative random error model
Authors: Wang Leyang , Xiao Hao
Published: July 2024

With the development of surveying and mapping science, the object of measurement adjustment has been extended from a single observation of the same kind in the past to different precisions of the same kind, or different kinds of observations. There are additive and multiplicative errors related to electronic instrument measurements, which affect the quality of the adjustment results. A single additive error model is difficult to meet the accuracy requirements, so a mixed additive and multiplicative random error model (MAMREM) is needed. Aiming at the problem of inaccurate MAMREM stochastic model, this paper proposes Helmert Variance Component Estimation (VCE) to determine the weight matrix in different types of observations under MAMREM. In this paper, the formula and iterative algorithm of Helmert variance component estimation applied to MAMREM are derived, and the weights of different kinds of observations in the adjustment process are estimated. In order to verify the effectiveness of the method, the digital elevation model experiment and the side network experiment are used to verify the method. The results prove the effectiveness of the method.
A study on the motion characteristics of particle in shear flow of active nematic fluid between two plates
Authors: Li Zhenna , Ye Hao , Lin Jianzhong
Published: July 2024

The motion characteristics of particle in shear flow of active nematic fluid between two plates are investigated numerically. The influence of activity intensity of active nematic fluids on the motion characteristics of particle is focused. The results showed that, when the activity intensity is high, the particle exhibits initially smooth trajectories and ultimately approximate Brownian motion. As the activity intensity increases, both the translational mean square displacement (MSDT) and rotational mean square displacement (MSDR) of the particle increase. The particle exhibits initially super-diffusive behavior and then normal diffusion. The unique vortex lattice mode in the flow plays a role in hindering particle motion, leading to a decrease in MSDT and MSDR. An increase in particle size will lead to a weakening of particle diffusion. In addition, there are topological defects in the active nematic fluid, and the number of topological defects N
def in the contractile system is greater than that in the extensible system, while the presence of particle has a smaller impact on N
def in the flow.