bluuebunny/crossref_metadata_2025 huggingface dataset:
Study and control of multilevel inverter topology with improved reliability and reduced number of components
Authors: Gaddala Srilaxmi , Reddy Damodhar
Published: September 2024

This article introduces a novel multilevel inverter design aimed at enhancing reliability and minimizing component count, thereby reducing maintenance costs for renewable energy systems. The suggested design uses six uni-directional swaps and one bidirectional swaps to produce voltage levels of 7, 11, and 19 in symmetrical and asymmetrical arrangements. Notably, the creation of any required number of voltage levels, including both positive and negative levels, is made possible by this design flexibility. Comparative analyses, encompassing factors such as total switch count, switch driver count, and overall blocking voltage, highlight how effective the suggested structure is in reducing the number of components. Furthermore, reliability evaluations show that the suggested inverter arrangement performs better than its equivalents. The MATLAB/Simulink simulation results and experimental validations from a lab prototype verify the viability and efficiency of the suggested multilevel inverter (PMI) topology. Through its innovative design, this inverter promises enhanced system reliability while minimizing maintenance requirements, thus presenting a significant advancement in renewable energy integration.
Power Electronic Converters Evolution In Transmission System: HVDC & FACTS Device
Authors: Rao D. S. N. M. , Cenate Theresa C.F. , Dhabliya Dharmesh , Alabdeli Haider , Hussein Abbas Hameed Abdul
Published: September 2024

Power electronics have helped achieve this objective of increasing capacity while improving reliability and sustainability and reducing operating costs over the years. They have provided added flexibility and control to power systems. As the use of renewable energy (RE) sources in faraway or isolated areas grows, it becomes necessary to integrate these alternative energy sources into the current power grid through long distance transmission systems. Within the realm of power electronic assets, FACTS and HVDC have had a significant impact on the development of sustainable grid infrastructure. Recent developments in power semiconductor devices, specifically in voltage source converter-based technology, have made it easier to use HVdc systems and FACTS devices in transmission networks. Converters with higher power ratings and more switches are being used more often for transferring large amounts of power and integrating renewable energy on a large scale. This has led to a greater need for effectively and efficiently managing power converter assets. The traditional HVDC system with line-commutated converters (LCC) and the HVDC system with pulse-width modulation (PWM) - voltage source converters (VSC) are evaluated using economic, technical, and environmental factors. Analyzed are different considerations regarding the installation of HVDC or FACTS devices to enhance the controllability of power transfer in power networks, particularly those with lengthy transmission lines.
A Perspective on the Evolution of Solar Cell and Solar Panel Materials
Authors: Guntreddi Venkataramana , Suresh Pala , Manoj Vasupalli , Babu Damala Rajesh , Swathi Aakula , Muhamad Mundu Mustafa
Published: September 2024

With the ever-increasing need for energy and the dwindling supply of traditional energy sources, solar power has emerged as a viable option. The sun’s rays are not only an inexhaustible supply of energy but also a noiseless and pollution-free option for power generation. It can readily make up for the energy needs met by other finite and potentially hazardous resources like fossil fuels and oil reserves. Sunlight is the primary medium through which solar energy reaches Earth. A solar cell employs the photovoltaic effect to transform the light from the sun into electricity. Cost and efficiency are the two biggest obstacles to expanding the use of solar cells. Another issue with solar power is its intermittent supply. Many studies aim to enhance the efficiency of solar cells in some way. New photovoltaic materials have increased solar cell efficiency to over 24% (PCE), up from below 10% during the advent of thin-film photovoltaic cells in the 1970s. Current solar cells have a significant cost premium over market rates, by as much as an order of magnitude. Nonetheless, the field has a bright future thanks to some recent advancements. First, we survey the history and current state of solar cell technology.
A PV-Powered Single Phase Seven-Level Inverter’s Photocurrent and Injected Power
Authors: Alkhafaij Mahdi abdulkhudur , Davala Karunakumar , Edwin Prabhakar P.B. , Jeshurun Subramania Bala , Ramy Riad Al-Fatlawy , Senthil Kumar R.
Published: September 2024

The PV inverter in this study is linked to the grid and its performance analysis is evaluated using a PI controller. It is a single phase multi-level PV inverter. The major objective of this research is to increase efficiency and eliminate harmonics caused by DC link voltage fluctuations created by Maximum Power Point Tracking (MPPT) during foggy situations. PV inverters generate and inject actual power into the main grid. This study uses a transformer-less photovoltaic inverter to cut down on losses, cost, and size. A transformer-less multilayer inverter is described in this paper. There is no high-frequency leakage current since that inverter can distribute both actual and reactive electricity. MATLAB/Simulink software was used to analyze and assess the effects of various PV-based seven-level techniques on the device’s Maximum Power Point Tracking (MPPT) performance.
Enhancements in Thermal energy storage systems employed in Solar Thermal Collectors
Authors: Rahman F. , Lalnunthari
Published: September 2024

Thermal projects are gaining popularity in the solar energy research community owing to their substantial energy storage density and efficiency in converting energy. Solar thermal collectors are technologies made to capture solar radiation and convert it into thermal energy. Solar collectors and storage mechanisms for thermal energy are the two main aspects in the aforementioned uses. Static solar thermal collectors use basic design concepts to efficiently collect, store, and transport solar heat in order to harvest solar energy. This research paper focuses on the most recent advancements and achievements in solar thermal utilisation, covering an assessment of solar collectors and thermal energy-storing systems. Thermal scenarios and the production of electricity from radiation from the sun are quickly evolving as the globe seeks future energy sources other than conventional ones. Solar thermal collectors are one of the most basic requirements for converting the solar energy into usable forms.
Improving the Dynamic Stability of Two Area Hydrothermal Power System Using Water Cycle Algorithm Tuned Controller
Authors: Sai Kalyan Ch. Naga , Bajaj Mohit , Varshney Niharika , Singh Arvind R.
Published: September 2024

Regulating the dynamical nature of the interconnected power system (IPS) due to fluctuating electric power demands is a crucial part of assessing its stability. The power demands on the IPS are continuous and require automatic actions to mitigate their subsequent impact. Thus, this work suggested the proportional-integral-derivative (PID) controller as the load frequency control (LFC) regulator using the robust optimization of the water cycle algorithm (WCA). The performance of the WCA tubed PID is tested on the two-area hydrothermal (TAHT) system, and the supremacy of the WCA is demonstrated with the Sooty tern algorithm (STA) and the grey wolf optimization (GWO) performance. Further, the TAHT is integrated with the HVDC line to attain further stability. The simulation analysis confirmed the enrichment in the TAHT performance with the HVDC line incorporation. Furthermore, the TAHT system is subjugated by the loading uncertainty under the suggested regulator. The investigation confirmed the robustness of the WCA-tuned PID performance.
Thermal Management System For A Lithium-Ion Battery Module Incorporating Discharge Rate And Cell Sequencing
Authors: Yadav Kamlesh Kumar , Kirit Dhablia Dharmesh
Published: September 2024

The growing need for high-performance lithium-ion battery modules in different applications requires the creation of effective thermal management systems to tackle the issues related to heat production and dissipation. The research introduces a new Hybrid Thermal Management System (HTMS) aimed at improving the thermal efficiency of Li-ion battery modules. HTMS uses active and passive cooling to enhance temperature regulation, reduce thermal strain, and prolong the battery’s lifespan. This study examines the dynamic thermal behaviour of an air- cooled Battery Thermal Management System (BTMS) at 1C discharge rate. This investigation will take into consideration a variety of design and flow adjustments, in addition to other factors. Moreover, the comprehensive integrated thermal-electrochemical model demonstrates that the thermal performance of the battery thermal management system (BTMS) is influenced by the quantity of battery cells, how the cells are arranged inside the module, and the air velocity. This is demonstrated by the fact that the BTMS is a thermal management system. This work investigates the standard deviation, heat generation plots, discharge curves, streamline profiles, temperature contours, average, and maximum temperature variation in the module. Additionally, the work determines the maximum temperature variation.
Shape optimization of keel in ship hydrodynamics using computational fluid dynamics
Authors: Miniappan P. K. , Krishnan R. , Abbas Haider M. , Elukaturi Sammaiah , Buddi Tanya
Published: September 2024

The optimization of composed techniques for plan upgrade taking into account massive extension numerical diversions (Reenactment Based Plan, SBD) is a clear example in computational applied mechanics. The key components of an SBD environment for shape enhancement are described and divided in the current paper. The focus is on complex planning smoothing out problems that involve nonlinear goals and computationally expensive objective capacities. Important level techniques adopted to lower the overall computational effort are presented; improvement estimates for problems involving nonlinear programming are examined; and selection strategies for shape assortment and grid control— both crucial to changing the volume organization to the forming shapes— are examined. Furthermore, taking into consideration the examples—that is, the distinctions between the numerically expected improvement of the objective ability and the certifiable improvement assessed in a serious exploratory mission, including considered numerical and preliminary weaknesses—a new Check and Endorsement (V&V) framework for studying errors and weaknesses in multiplication-based upgrades is introduced. Then, two distinct SBD structures are introduced and shown on a challenging current problem, specifically the optimal shape upgrade of a transport under real-world numerical and practical requirements, whose evaluation throughout the progression cycle includes recurrent Reynolds game plans. found the Navier-Works up conditions center worth. In order to support the calculations and evaluate the outcome of the smoothing out framework, an exploration mission is finally completed on the two better models. Beyond the exploratory and numerical shortcomings, both the revised models demonstrate more produced credits, confirming the validity of the SBD frameworks.
Experimental and numerical validation of the energy-saving performance of a passive pcm floor for a real-scale building
Authors: Sundaram N. Kalyana , Maruthamuthu R. , Alsalami Zaid , Alkhafaij Mahdi abdulkhudur , Srividya Devi P. , Senthil Kumar R.
Published: September 2024

A greater knowledge of the intrinsic unpredictability of the Earth’s climate system and its expected response to natural and human factors is being provided by scientific advances and improved climate change observation. The way that the Earth system reacts to changes in radiative forcings will determine how climate change affects the environment and civilization. It will also rely on how humanity adapts via changes in economics, technology, policy, and lifestyle. Future scenarios must be used to examine the possible outcomes of various response options since there are a lot of uncertainty regarding the forces and reactions to climate change in the future. According to this study, phase change material (PCM) has the ability to hold heat at a steady temperature, which helps to lower the energy usage of buildings. This is a PCM board that has been made to store heat in order to lower the power required for temperature regulation, the PCM boards were used as the floor in the real-scale office. This resulted in lower energy usage by eighteen and twenty percentages in the winter. To assess long-term performance, experimental data verify a numerical model. The findings of the simulation and experiment show that a high-performance PCM floor may effectively reduce the amount of electricity used for heating and cooling.
Contribution of Bergama Wind Power Plants to Turkey’s General Energy Consumption
Authors: Ozfirat Muharrem Kemal , Eyuboglu Ali Kemal , Tekir Ugur , Yetkin Mustafa Emre
Published: September 2024

Wind energy has a 10.4% share of the 326.3 TWh electrical energy consumed in Turkey in 2023, and this study focuses on this percentage. More specifically, it considered the power of seven wind energy power plants in Izmir’s Bergama district in this consumption. The power plants in Bergama generated a total of 1.259 million kWh in 2023. In Izmir, they contributed 0.26% to 2% of energy consumption nationally, and between 0.01% and 0.13% throughout Turkey. Still, the Bergama Wind Power Plant produced the most, while the 2% consumption rate in Izmir and the 0.13% consumption rate across Turkey stand out. Overall, this analysis assesses the power plants’ energy production based on their efficiency and the contribution to the overall consumption of energy nationally, using a comparison based on production and consumption rates. Therefore, the results should demonstrate the immense potential of investing in this field to increase Turkey’s energy diversity and security, stressing the need for renewable energy to dominate energy consumption.
Teaching mask dances through interactive media for international students in South Korea
Authors: Masunah Juju , Park Nahoon , Patogian Romario
Published: September 2024

The purpose of this article is to describe the research result of teaching mask dances through interactive media for international students in South Korea. The research answered these questions: how does one design and implement teaching mask dances through interactive media for international students in South Korea? How do international students in South Korea appreciate mask dances after learning through interactive media? This research used experimental method, one shot case study. Participants of this research used purposive sampling with 10 International Students who took a performing arts basecamp class in Young San University, South Korea. One of the researchers was a participant observer, and he taught a Priangan mask dance from Indonesia. Data were collected through virtual interviews, questionnaires, and study of documentations. Data were analyzed using triangulation. Findings show that the international students in South Korea accomplished these scores based on three domains: They received 91% for their affective score, 89% for their cognitive score, and 95% for psychomotor’s score. In summary, teaching mask dances through interactive media increased international students’ appreciation to Indonesian’s dances.
Exploring the impact of TikTok affiliate marketing on creativity among art and design students
Authors: Aziz Mohd Nasiruddin Abdul
Published: September 2024

The researcher investigates the impact of TikTok affiliate marketing on creativity among art and design students at University Teknologi MARA, Perak Branch, Malaysia. This article presents a SWOT analysis through the practical experience within one semester. The approach was implemented during an advertising class, where students engaged in creative idea generation and video editing to compete against each other. The student’s assessment relied on data analytics, measuring both sales performance and video engagement. Notably, the assessment process involved the global TikTok community as “world citizens” became assessors, effectively measuring the impact and creativity of the students’ marketing efforts. As a result, the students displayed enthusiasm for this assignment, as it transcended the conventional boundaries of a typical academic task. Beyond merely seeking a grade, students were immersed in an experiential learning process that introduced them to the dynamic world of digital marketing on demand. Moreover, their participation in TikTok affiliate marketing enabled them to access additional benefits, such as free product reviews, selling commissions, and the opportunity to support local entrepreneurs through promotion. Overall, this research highlights the potential of TikTok affiliate marketing as an effective tool for fostering creativity and practical skills among art and design students, empowering them with valuable insights into the digital marketing landscape while contributing positively to the wider business ecosystem.
Entzündlich-rheumatische Erkrankung des Vorfußes
Authors: Plöger Sebastian
Published: September 2024

Der Text beschreibt die Auswirkungen und Behandlungsmöglichkeiten der entzündlich-rheumatischen Erkrankung des Vorfußes, die zu chronischer Entzündung und Zerstörung der Gelenke und angrenzender Gewebe führt. Der Vorfuß ist bei vielen Rheumapatienten von Schmerzen betroffen, was oft zu einer erheblichen Einschränkung im Alltag führt. Trotz Fortschritten in der medikamentösen Therapie bleiben Fußprobleme ein herausforderndes Problem, da viele Patienten eine erosive Zerstörung der Gelenke zeigen. Die Behandlung erfordert einen interdisziplinären Ansatz aus orthopädischer und internistischer Rheumatologie, Orthopädietechnik und Physiotherapie. Ziel ist es, den Krankheitsprozess zu verlangsamen, Schmerzen zu reduzieren und die Lebensqualität zu verbessern. Operative Eingriffe werden bei fortgeschrittener Gelenkdestruktion in Betracht gezogen, um Schmerzen zu lindern und die Fußfunktion wiederherzustellen. Die Entscheidung für eine Operation hängt von verschiedenen Faktoren ab. Insgesamt stellt die Behandlung der entzündlich-rheumatischen Vorfußdestruktion eine komplexe Herausforderung dar, die eine enge Zusammenarbeit verschiedener medizinischer Fachrichtungen erfordert, um die bestmögliche Versorgung der Patienten zu gewährleisten.
Therapeutische Fenster in der Orthopädischen Rheumatologie: die ulnare Deviation der Langfinger
Authors: Maria Pothmann Carina Eva
Published: September 2024

Die Ulnardeviation der Langfinger ist eine häufige rheuma-orthopädische Herausforderung. Durch den entzündlichen, oft auch ossär destruktiven Gelenkbefall resultiert eine Instabilität mit folgender Abweichung der Finger in Richtung der Ulna. Dies führt zu einem meist schmerzhaften, konsekutiven Funktionsverlust mit deutlicher Einschränkung der Lebensqualität bis hin zur Autonomie der Betroffenen. Die Behandlung dieser Deformität ist komplex und erfordert ein tiefes Verständnis der Pathophysiologie sowie der therapeutischen Optionen. Diese Arbeit soll den Lesern als Information und Leitfaden zur Detektion des therapeutischen Fensters und somit zeit- und symptomgerechten Behandlung ihrer Patienten dienen.
Drohende Sehnenruptur beim Rheumatiker
Authors: Arbogast Martin
Published: September 2024

Die Synovialis der Sehnen kann sich bei entzündlich-rheumatischen Erkrankungen ähnlich aggressiv verhalten wie die Synovialis in den Gelenken. Ob epitendinös oder auch intratendinös werden Botenstoffe ausgesandt, die die Sehnenstruktur schädigen, insuffizient werden lassen und letztendlich eine Ruptur erzeugen können. Auch über langdauernde Kompression oder mechanische Kompromittierung drohen Sehnenrupturen. Wie bei traumatisch entstandenen Schäden, werden auch bei entzündlich bedingten Veränderungen Reparationsprozesse in die Wege geleitet, die eine Regeneration der Sehnen möglich machen. Entzündlich bedingte Sehnenrupturen entstehen meist langsam und bereiten wenig Schmerzen. Die Funktionsminderung diktiert das diagnostische und therapeutische Prozedere. Durch die medikamentöse Beeinflussung der entzündlichen Prozesse verlangsamen sich die tenosynovialen Reaktionen. Der entzündliche Sehnenmitbefall ist in keinem Score zur Aktivität der Grunderkrankung mitberücksichtigt. Wann und wo Sehnenrupturen auftreten und in welchen therapeutischen Fenstern dies verhindert werden kann, soll in dieser Arbeit erörtert werden.
Pyarthritis und periprothetische Infektionen
Authors: Carl Hans-Dieter
Published: September 2024

Die septische Arthritis stellt – als Pyarthritis des nativen Gelenks oder als periprothetische Infektion – einen medizinischen Notfall dar. Da es bei Patienten mit einer entzündlich-rheumatischen Grunderkrankung erschwert zu diagnostizieren sein kann, möchte der folgende Artikel den Leser für dieses Krankheitsbild sensibilisieren und hierzu die Leitsymptome, die diagnostischen sowie die therapeutischen Maßnahmen darstellen.
Die IgA(Purpura Schönlein-Henoch)-Vaskulitis
Authors: Hospach Anton , Müller Dominik , Pohl Martin
Published: September 2024

Die IgA-Vaskulitis (früher Purpura Schönlein-Henoch) ist eine systemische, immunkomplexvermittelte Vaskulitis der kleinen Gefäße, die gekennzeichnet ist durch die klinische Trias aus palpabler Purpura, Bauch- und Gelenkschmerzen. Es ist die häufigste Vaskulitis im Kindes- und Jugendalter. Die Diagnose ist klinisch zu stellen. Die kutane Vaskulitis zeigt überwiegend eine Spontanremission. Die Nieren sind häufig und in unterschiedlichem Ausmaß betroffen. Bei schweren Verläufen können ein akutes Nierenversagen und ein nephrotisches Syndrom auftreten sowie renale Langzeitschäden verbleiben.
Strain engineering in 2D FETs: Physics, status, and prospects
Authors: Kumar Ankit , Xu Lin , Pal Arnab , Agashiwala Kunjesh , Parto Kamyar , Cao Wei , Banerjee Kaustav
Published: September 2024

In this work, we explore the physics and evaluate the merits of strain engineering in two-dimensional van der Waals semiconductor-based FETs (field-effect-transistors) using DFT (density functional theory) to determine the modulation of the channel material properties under strain, and subsequently, their effect on carrier transport properties, i.e., scattering rates, mobility, and then finally simulate and analyze dissipative current transport with a non-equilibrium Green's function–Poisson's equation self-consistent solver. The scattering model includes the effects of charged impurities, intrinsic phonons, and remote phonons as well as the screening effect due to charged carriers. Impact of strain engineering on contact resistance is also incorporated into the transport simulations to determine the potential performance enhancements using strain in practical devices. Based on the comprehensive simulation results, we identify the materials and strain configuration that provide the best improvement in performance. We demonstrate an ON-current gain of 43.3% in a biaxially compressively strained monolayer MoSe2 device achieved through unique valley-crossing. Furthermore, implications of strain engineering for emerging energy-efficient devices based on band-to-band tunneling and spintronics are evaluated to explore uncharted frontiers in beyond-CMOS electron devices.
An experimental study of the impact of various infill parameters on the compressive strength of 3D printed PETG/CF
Authors: Patil Shashwath , Sathish T. , Giri Jayant , Felemban Bassem F.
Published: September 2024

This study examines the effect of different infill patterns and percentages on the compressive strength attributes of carbon fiber-reinforced PETG samples printed using fused deposition modeling, employing response surface methodology. Carbon fiber-enhanced PETG (polyethylene terephthalate glycol) composites represent a cutting-edge advancement in additive manufacturing, drawing significant interest due to their impressive mechanical attributes. The experimentation involves modifying printing parameters such as the infill pattern (tri-hexagon, cubic, or line) and infill density (40%, 60%, and 80%). These parameter values were obtained through a central composite experimental design utilizing response surface methodology. The compressive strength of the 3D-printed carbon fiber-reinforced PETG specimens is assessed following ASTM D695 standards. Research indicates that increasing the density of the infill results in enhanced compressive strength. Specifically, specimens featuring an 80% infill density with a tri-hexagon pattern demonstrate a notable compressive strength of 39.16 MPa. By employing regression analysis and optimization techniques, the study predicts experimental outcomes accurately. These findings offer valuable insights into refining the manufacturing process of carbon fiber-reinforced PETG components. This advancement holds potential benefits across various engineering fields, particularly in automotive and aerospace industries, where strength and durability are essential.
EFIT-Prime: Probabilistic and physics-constrained reduced-order neural network model for equilibrium reconstruction in DIII-D
Authors: Madireddy S. , Akçay C. , Kruger S. E. , Amara T. Bechtel , Sun X. , McClenaghan J. , Koo J. , Samaddar A. , Liu Y. , Balaprakash P. , Lao L. L.
Published: September 2024

We introduce EFIT-Prime, a novel machine learning surrogate model for EFIT (Equilibrium FIT) that integrates probabilistic and physics-informed methodologies to overcome typical limitations associated with deterministic and ad hoc neural network architectures. EFIT-Prime utilizes a neural architecture search-based deep ensemble for robust uncertainty quantification, providing scalable and efficient neural architectures that comprehensively quantify both data and model uncertainties. Physically informed by the Grad–Shafranov equation, EFIT-Prime applies a constraint on the current density Jtor and a smoothness constraint on the first derivative of the poloidal flux, ensuring physically plausible solutions. Furthermore, the spatial location of the diagnostics is explicitly incorporated in the inputs to account for their spatial correlation. Extensive evaluations demonstrate EFIT-Prime's accuracy and robustness across diverse scenarios, most notably showing good generalization on negative-triangularity discharges that were excluded from training. Timing studies indicate an ensemble inference time of 15 ms for predicting a new equilibrium, offering the possibility of plasma control in real-time, if the model is optimized for speed.
Widely tunable Ka-band optoelectronic oscillator integrated on thin film lithium niobate platform
Authors: Ma Rui , Huang Zijun , Ke Wei , Wang Xichen , Hao Peng , Yao X. Steve , Cai Xinlun
Published: September 2024

We report a novel widely tunable Ka-band optoelectronic oscillator (OEO) realized by integrating a Mach–Zehnder modulator (MZM), a thermally-tunable add-drop micro-ring resonator (MRR), and a Mach–Zehnder interferometer (MZI) on the thin film lithium niobate platform, with the MZM and the MRR sequentially situated in one of the MZI arms. The MZM is for modulating the optical carrier, while the add-drop MRR is for selecting a single modulation sideband to beat with the unmodulated optical carrier from the other arm of the MZI, such that the OEO oscillation frequency is determined by the frequency spacing between the optical carrier and the selected modulation sideband, while the frequency tuning range is determined by the free spectral range of the MRR. By tuning the resonances of the add-drop MRR, the oscillation frequency can be tuned from 20 to 35 GHz, with the phase noises of −85 dBc/Hz @10 kHz and −116 dBc/Hz @100 kHz in the whole tuning range, which represent much higher oscillation frequency, much wider frequency tuning range, and lower phase noise than those of the photonic integrated OEOs realized with other material platforms reported previously.
Effect of branch angle on wind-induced loads of a sympodial tree
Authors: Lin Pengfei , Hu Gang , Tse K. T. , Leung Anthony Kwan
Published: September 2024

Ideal tree exhibits fractal characteristics, where the branch angle plays a significant role in shaping the morphology of trees, thereby influencing their wind resistance capabilities. Nevertheless, investigation into the aerodynamic effects of branch angle on trees with leaves remains relatively scarce. By subjecting various tree morphologies to controlled wind conditions, this study scrutinizes the aerodynamic responses and resulting loads experienced by one-order sympodial trees with differing branch angle configurations. The results reveal that the tree experiences unstable oscillations induced by irregular leaf vibration with an increase in wind speed, resulting in a rise in drag coefficient. Meanwhile, despite a higher drag force observed in the tree with higher branch angle at wind speeds below 20 m/s, the tree exhibits superior reconfiguration capabilities, enabling it to withstand stronger winds effectively. Subsequently, a reconfiguration process for the one-order sympodial tree is proposed, exhibiting a wavy streamlining effect. Finally, it is found that the sympodial tree structure can be regarded as a high-frequency filter to dissipate high-frequency branch vibration energy. The findings from this research endeavor hold significant implications for enhancing our understanding of the aerodynamics of trees with different morphology and the cultivation and selection of urban trees.
Coherent mode and turbulence measurements with a fast camera
Authors: Bartolo Gustavo E. , Yadav Sonu , Fitz Chloelle , Scime Earl E.
Published: September 2024

This study employs a fast camera with frame rates up to 900,000 fps to measure the transfer of energy across spatial scales in helicon source plasmas and during flux rope mergers and the measurement of azimuthal mode structures in helicon plasmas. By extracting pixel-scale dispersion relations and power spectral density (PSD) measurements, we measure the details of turbulent wave modes and energy distribution across a broad range of spatial scales within the plasma. We confirm the presence of drift waves in helicon plasmas, as well as the existence of strong dissipation regions in the PSD at electron skin depth scales for both helicon and flux rope merger experiments. This approach overcomes many limitations of conventional probes, providing high spatial and temporal resolution, without perturbing the plasma.
Riddled basins of chaotic synchronization and unstable dimension variability in coupled Lorenz-like systems
Authors: Czajkowski Bruno M. , Viana Ricardo L.
Published: September 2024

Unstable dimension variability is an extreme form of non-hyperbolic behavior that causes a severe shadowing breakdown of chaotic trajectories. This phenomenon can occur in coupled chaotic systems possessing symmetries, leading to an invariant attractor with riddled basins of attraction. We consider the coupling of two Lorenz-like systems, which exhibits chaotic synchronized and anti-synchronized states, with their respective basins of attraction. We demonstrate that these basins are riddled, in the sense that they verify both the mathematical conditions for their existence, as well as the characteristic scaling laws indicating power-law dependence of parameters. Our simulations have shown that a biased random-walk model for the log-distances to the synchronized manifold can accurately predict the scaling exponents near blowout bifurcations in this high-dimensional coupled system. The behavior of the finite-time Lyapunov exponents in directions transversal to the invariant subspace has been used as numerical evidence of unstable dimension variability.
A new approach to evaluate obstructive sleep apnea according to body mass index using breathing diagram
Authors: Islam Md. Didarul , Kim Jeong Sik , Jeon Sang Jin , Kang Hyo Jeong , Kim Kyung-Wuk , Jeon Min-Gyu , Lee Seung Bae , Kim Min Uk , Choi Young Ho , Kim Hyoung-Ho
Published: September 2024

Several studies have investigated predictive factors such as morphological, physiological, and fluid dynamics perspectives for obstructive sleep apnea (OSA) using computed tomography imaging, computer simulations, and experiments. Computational fluid dynamics is used in this study to analyze airflow in the upper airway across different body mass index (BMI) groups to identify suitable factors for predicting OSA. A comparative analysis is conducted on three groups: normal BMI (22.8 ± 1.0), overweight BMI (31.8 ± 1.5), and OSA (28.6 ± 3.3), with nine participants in each group. Geometric parameters were analyzed in addition to fluid dynamics factors. A comparison of the geometric variables revealed that the OSA group had the shortest total airway length (1.5 × 10−1 m) and the smallest volume (5.4 × 10−5 m3). However, t-test results showed low statistical significance for these differences. For fluid dynamics variables, the OSA group experienced the highest pressure drop (−46.8 Pa) and the highest adjusted pressure coefficient (Cp = 0.88) compared to the other two groups. From the analysis of breathing diagrams, the OSA group exhibited the largest area under the breathing power curve (32.6 × 10−3 N m/s) followed by the normal weight (24.9 × 10−3 N m/s) and overweight (21.0 × 10−3 N m/s) groups in descending order. Analysis of fluid dynamics factors indicated that the OSA group exhibited significantly higher pressure drop and pressure coefficient values compared to other groups although the differences between the groups were less significant. Finally, one key finding from this research highlights a new computational approach that relies on the breathing diagram. This new approach could provide more accurate insights into predicting and managing OSA due to their distinctive shapes.
Symmetry change of quantum electron solids in double layer MoS2
Authors: Chui S. T. , Huang Meizhen , Wu Zefei , Wang Ning
Published: September 2024

Electrons in transition metal dichalcogenides stacked on opposite sides of BN of thickness d can form solids, which have no long range position order but are characterized by a finite shear modulus. The melting temperature Tm is characterized by the occurrence of unbound quantum topological defects. Tm of this solid is four orders of magnitude larger than that of previously studied electron solids in Si-MOSFETs. As the density n = n0 × 1012/cm2 is changed so that both the top and the bottom electron densities are the same, for n0 > 1.5 with d = 5 nm, a hexagonal solid is manifested experimentally by a five order of magnitude increase in Coulomb drag resistance Rdrag at room temperature. This resistance change corresponds to a four orders of magnitude better subthreshold slope, the key parameter for semiconductor device low power switching, over existing limits for MOSFETs from “Boltzmann’s tyranny.” The symmetry of the two-layer solid can be tuned by varying the density. The hexagonal lattice becomes soft at n0 ≈ 1.5. There is a further two orders of magnitude increase in Rdrag due to an increase in disorder caused by the large quantum fluctuation of the lattice position that is of 0.4 order of the lattice spacing. The subthreshold slope is improved by two more orders of magnitude. For n0 < 1.5, different phases of the solid corresponding to peaks of Rdrag of different magnitude at different gate voltages start to form. This raises the intriguing possibility of making new classes of devices with ternary and higher order systems where the different phases correspond to different logical states and not just two states of on (low resistance) and off (high resistance).
Flow sensing of a solid plate in the wake vortex street
Authors: Tong Xinyu , Kang Linlin , Fan Dixia
Published: September 2024

Understanding the mechanisms by which fish sense vortical perturbations is crucial for both biological insights and technological advancements. We investigate the hydrodynamics of a solid plate moving vertically through the reverse Kármán vortex street generated by a horizontally moving flexible flapping plate in a viscous flow. The impacts of the horizontal distance between the two plates (D) and the moving speed of the solid plate (vy) are considered. The horizontal distance determines the vortical environments, i.e., whether the solid plate impinges through the vortex cores or the gaps. Different vortical environments exhibit varying vortex-induced velocities, resulting in distinct force and pressure patterns on the solid plate. The evolution of these sensed forces and pressures is mapped along the path of the solid plate, suggesting a potential mechanism by which fish detect the position and properties of surrounding vortices. Furthermore, it is found that increasing speed can amplify the sensed force and pressure signals by thinning boundary layers and strengthening friction force. Nevertheless, the established mapping relationships remain applicable across varying velocities, and a scaling relation has been derived to normalize this amplification effect on the vertical force. These findings enhance our understanding of fish sensory mechanisms and could inspire innovative designs and control strategies for underwater vehicles.
Graphene–insulator–metal diodes: Enhanced dielectric strength of the Al2O3 barrier
Authors: Kunc J. , Fridrišek T. , Shestopalov M. , Jo J. , Park K.
Published: September 2024

We studied the transport properties of graphene–insulator–metal tunneling diodes. Two sets of tunneling diodes with Ti–Cu and Cr–Au top contacts are fabricated. Transport measurements showed state-of-the-art non-linearity and a critical influence of the top metals on the dielectric strength of the tunneling barrier. X-ray photoelectron spectroscopy indicated two methods for enhancing the dielectric strength of the tunneling barrier. These are the optimized seed layers for the growth of high-quality conformal insulators and the selection of appropriate top metal layers with a small diffusion coefficient and electromigration into the Al2O3 barrier. The Cr–Au top contact provides superior characteristics to the Ti–Cu metallization. X-ray photoelectron spectroscopy showed significant diffusion of titanium during the Al2O3 growth and the formation of titanium inclusions after annealing. Chromium diffusion is slower than that of titanium, making chromium contact more suitable for the reliable operation of tunneling diodes. As a result, we demonstrate a 40% improvement in the dielectric strength of the tunneling barrier compared to state-of-the-art metal–insulator–metal diodes.
On the entry of cylindrical disks into non-Newtonian fluid mixtures
Authors: Ebrahimi Mohammadamin , Azimi Amir Hossein
Published: September 2024

A series of laboratory experiments was conducted to investigate solid object characteristics and fluid properties on the free fall of cylindrical disks into stagnant non-Newtonian ambient. The viscosity and yield stress of the ambient fluid mixtures were controlled by adjusting the concentration of a polymer. Six different fluid mixtures were prepared to develop a relatively wide range of fluid viscosities and yield stresses to examine the behavior of free-falling disks in accordance with the variations in the disk's geometry, density, and mixture parameters. The effects of disks’ parameters, such as disk aspect ratio and relative density, on crown formation, pinch-off characteristics, and splash evolution were studied. Experimental results indicated that increasing the disk's density increased the pinch-off depth while a reduction in aspect ratio increased the pinch-off depth. The sinking time diminished with increasing the aspect ratio of disks, and such observations were independent of the rheological characteristics of the fluid mixture. The same devaluation was also experienced for the height of the crown. As the disk's density reduced, the splash curtain became smoother and the waves’ intensity attenuated. The energy losses were found to be correlated with the aspect ratio, density, and fluid viscosity. The augmentation of energy losses was linked with different parameters such as aspect ratio, disk density, and ambient fluid viscosity.
Comprehensive device modeling and performance analysis of (Cs, FA)Pb(I, Br)3 based perovskite–silicon tandem solar cells
Authors: Wu Zhenhui , Pan Zhaoyao , Yang Jinpeng
Published: September 2024

The utilization of perovskite films as the top subcell to form a perovskite–silicon tandem solar cell has emerged as an attractive approach to achieve higher power conversion efficiency (PCE) that could surpass the Shockley–Queisser limit for single silicon junction. Despite these efforts, precisely understanding and predicting the underlying mechanism necessary for obtaining higher PCE remains a challenging task. In particular, the absorption due to back electrode reflection during calculations has often been neglected, resulting in an underestimation when comparing theoretical calculations to experimental conditions. In this study, we conduct a comprehensive investigation of perovskite–silicon tandem solar cells with considering the back electrode reflection to study the detailed influence on film quality of perovskite films, where a detailed analysis of multiple factors such as bulk and interface defects, doping levels, and carrier mobility from (Cs, FA)Pb(I, Br)3 has been conducted to unveil their effects on device performance. Our results revealed that lower bulk/interface defect concentrations and higher carrier mobility are critical factors contributing to the best device performance, where the highest PCE would reach up to 37.40%. Further comparison with experimental results also confirms the importance of employing effective methods to reduce surface/interface trap densities in order to enhance overall performance. These findings offer valuable theoretical insights for the guidance of experimental designs of perovskite–silicon tandem solar cells.
Plasma cell-free RNA signatures of inflammatory syndromes in children
Authors: Loy Conor J. , Servellita Venice , Sotomayor-Gonzalez Alicia , Bliss Andrew , Lenz Joan S. , Belcher Emma , Suslovic Will , Nguyen Jenny , Williams Meagan E. , Oseguera Miriam , Gardiner Michael A. ,   P.E.M.K.D.R.G.,   the C.H.A.R.M.S. the Study Group, Choi Jong-Ha , Hsiao Hui-Mien , Wang Hao , Kim Jihoon , Shimizu Chisato , Tremoulet Adriana H. , Delaney Meghan , DeBiasi Roberta L. , Rostad Christina A. , Burns Jane C. , Chiu Charles Y. , De Vlaminck Iwijn , Austin-Page Lukas , Bryl Amy , Donofrio-Ödmann Joelle , Ekpenyong Atim , Gutglass David , Herskovitz Scott , Ishimine Paul , Kanegaye John , Nguyen Margaret , Nguyen Mylinh , Schwartz Kristy , Ulrich Stacey , Vayngortin Tatyana , Zimmerman Elise , Ang Jocelyn , Rosenkranz Margalit , Bochini Joseph , Sykes Michelle , Morgan Lerraughn , D’Addese Laura , Gutierrez Maria Pilar
Published: September 2024

Inflammatory syndromes, including those caused by infection, are a major cause of hospital admissions among children and are often misdiagnosed because of a lack of advanced molecular diagnostic tools. In this study, we explored the utility of circulating cell-free RNA (cfRNA) in plasma as an analyte for the differential diagnosis and characterization of pediatric inflammatory syndromes. We profiled cfRNA in 370 plasma samples from pediatric patients with a range of inflammatory conditions, including Kawasaki disease (KD), multisystem inflammatory syndrome in children (MIS-C), viral infections, and bacterial infections. We developed machine learning models based on these cfRNA profiles, which effectively differentiated KD from MIS-C—two conditions presenting with overlapping symptoms—with high performance [test area under the curve = 0.98]. We further extended this methodology into a multiclass machine learning framework that achieved 80% accuracy in distinguishing among KD, MIS-C, viral, and bacterial infections. We further demonstrated that cfRNA profiles can be used to quantify injury to specific tissues and organs, including the liver, heart, endothelium, nervous system, and the upper respiratory tract. Overall, this study identified cfRNA as a versatile analyte for the differential diagnosis and characterization of a wide range of pediatric inflammatory syndromes.
Structural basis for surface activation of the classical complement cascade by the short pentraxin C-reactive protein
Authors: Noone Dylan P. , Isendoorn Marjolein M. E. , Hamers Sebastiaan M. W. R. , Keizer Mariska E. , Wulffelé Jip , van der Velden Tijn T. , Dijkstra Douwe J. , Trouw Leendert A. , Filippov Dmitri V. , Sharp Thomas H.
Published: September 2024

Human C-reactive protein (CRP) is a pentameric complex involved in immune defense and regulation of autoimmunity. CRP is also a therapeutic target, with both administration and depletion of serum CRP being pursued as a possible treatment for autoimmune and cardiovascular diseases, among others. CRP binds to phosphocholine (PC) moieties on membranes to activate the complement system via the C1 complex, but it is unknown how CRP, or any pentraxin, binds to C1. Here, we present a cryoelectron tomography (cryoET)-derived structure of CRP bound to PC ligands and the C1 complex. To gain control of CRP binding, a synthetic mimotope of PC was synthesized and used to decorate cell-mimetic liposome surfaces. Structure-guided mutagenesis of CRP yielded a fully active complex able to bind PC-coated liposomes that was ideal for cryoET and subtomogram averaging. In contrast to antibodies, which form Fc-mediated hexameric platforms to bind and activate the C1 complex, CRP formed rectangular platforms assembled from four laterally associated CRP pentamers that bind only four of the six available globular C1 head groups. Potential residues mediating lateral association of CRP were identified from interactions between unit cells in existing crystal structures, which rationalized previously unexplained mutagenesis data regarding CRP-mediated complement activation. The structure also enabled interpretation of existing biochemical data regarding interactions mediating C1 binding and identified additional residues for further mutagenesis studies. These structural data therefore provide a possible mechanism for regulation of complement by CRP, which limits complement progression and has consequences for how the innate immune system influences autoimmunity.
Engaging with bad (meta)data in historical corpus linguistics
Authors: Vartiainen Turo , Säily Tanja
Published: September 2024

In this chapter, we discuss some common pitfalls related
to historical data and its use in linguistic analysis. We argue that the
“philologist’s dilemma”, as originally proposed by Rissanen (1989), should be reconceptualized to meet
the needs of the fast-evolving field of corpus linguistics, where scholars
make increasing use of big-data resources and sophisticated statistical
modelling. By providing examples of errors and uncertainties related to, for
example, corpus metadata, sampling, balance, and OCR accuracy, we argue that
corpus linguists should pay increasingly close attention to the sampling and
annotation principles employed in the compilation of historical corpora as
well as to the quality of the linguistic data. We propose that the principle
of “knowing one’s corpus” in terms of its compilation principles has become
all the more important in the age of big-data corpora, where it is not
feasible for individual researchers, or corpus compilers, to validate their
data manually.