bluuebunny/crossref_metadata_2025 huggingface dataset:
Pre-exposure prophylaxis and telemedicine during coronavirus (COVID-19): a qualitative study of the experiences of health care professionals in Mexico
Authors: Cruz-Bañares A. , Rojas-Carmona A. , Aguilera-Mijares S. , Martínez-Dávalos A. , Bautista-Arredondo S. , Vermandere H.
Published: April 2024

Background Telemedicine, which involves utilising technologies for remote health care delivery, proved useful to continue offering certain health services during the coronavirus disease 2019 (COVID-19) lockdown. However, the extent of its effectiveness in delivering pre-exposure prophylaxis services for HIV prevention remains underexplored from the viewpoint of health care providers. Therefore, this study aimed to assess the experiences of health care professionals in Mexico who utilised telemedicine for delivering pre-exposure prophylaxis services during the COVID-19 contingency. Methods A qualitative study was performed: 15 virtual interviews with health care professionals were conducted, transcribed and coded in ATLAS.ti. Results The results indicate that telemedicine effectively mitigated COVID-19 exposure, facilitated users’ access to pre-exposure prophylaxis counselling, minimised waiting times and enhanced health care professionals’ perceived control during sessions. While implementing remote services, certain organisational challenges, which were somewhat latent before the pandemic, became more apparent: colleagues recognised the necessity for more formal communication channels to disseminate information effectively. Additionally, there was a recognised need for electronic patient files to streamline data-sharing processes. An optimal approach would involve a blend of face-to-face and virtual services, contingent upon the availability of essential infrastructure, well-defined implementation protocols and comprehensive training programs. Conclusions Telemedicine streamlined certain processes, garnered positive acceptance from healthcare professionals and holds promise as a valuable post-pandemic tool for improving retention among pre-exposure prophylaxis users.
Chaotic neural dynamics facilitate probabilistic computations through sampling
Authors: Terada Yu , Toyoizumi Taro
Published: April 2024

Cortical neurons exhibit highly variable responses over trials and time. Theoretical works posit that this variability arises potentially from chaotic network dynamics of recurrently connected neurons. Here, we demonstrate that chaotic neural dynamics, formed through synaptic learning, allow networks to perform sensory cue integration in a sampling-based implementation. We show that the emergent chaotic dynamics provide neural substrates for generating samples not only of a static variable but also of a dynamical trajectory, where generic recurrent networks acquire these abilities with a biologically plausible learning rule through trial and error. Furthermore, the networks generalize their experience in the stimulus-evoked samples to the inference without partial or all sensory information, which suggests a computational role of spontaneous activity as a representation of the priors as well as a tractable biological computation for marginal distributions. These findings suggest that chaotic neural dynamics may serve for the brain function as a Bayesian generative model.
Body mass index–dependent shifts along large-scale gradients in human cortical organization explain dietary regulatory success
Authors: Janet Rémi , Smallwood Jonathan , Hutcherson Cendri A. , Plassmann Hilke , Mckeown Bronte , Tusche Anita
Published: April 2024

Making healthy dietary choices is essential for keeping weight within a normal range. Yet many people struggle with dietary self-control despite good intentions. What distinguishes neural processing in those who succeed or fail to implement healthy eating goals? Does this vary by weight status? To examine these questions, we utilized an analytical framework of gradients that characterize systematic spatial patterns of large-scale neural activity, which have the advantage of considering the entire suite of processes subserving self-control and potential regulatory tactics at the whole-brain level. Using an established laboratory food task capturing brain responses in natural and regulatory conditions (N = 123), we demonstrate that regulatory changes of dietary brain states in the gradient space predict individual differences in dietary success. Better regulators required smaller shifts in brain states to achieve larger goal-consistent changes in dietary behaviors, pointing toward efficient network organization. This pattern was most pronounced in individuals with lower weight status (low-BMI, body mass index) but absent in high-BMI individuals. Consistent with prior work, regulatory goals increased activity in frontoparietal brain circuits. However, this shift in brain states alone did not predict variance in dietary success. Instead, regulatory success emerged from combined changes along multiple gradients, showcasing the interplay of different large-scale brain networks subserving dietary control and possible regulatory strategies. Our results provide insights into how the brain might solve the problem of dietary control: Dietary success may be easier for people who adopt modes of large-scale brain activation that do not require significant reconfigurations across contexts and goals.
The first peoples of the Atacama Desert lived among the trees: A 11,600- to 11,200-year-old grove and congregation site
Authors: Ugalde Paula C. , Joly Delphine , Latorre Claudio , Gayo Eugenia M. , Labarca Rafael , Simunovic Mikhaela , McRostie Virginia , Holliday Vance T. , Quade Jay , Santoro Calogero M.
Published: April 2024

In deserts, water has been singled out as the most important factor for choosing where to settle, but trees were likely an important part of the landscape for hunter-gatherers beyond merely constituting an economic resource. Yet, this critical aspect has not been considered archaeologically. Here, we present the results of mapping and radiocarbon dating of a truly unique archaeological record. Over 150 preserved stumps around five Late Pleistocene/Early Holocene archaeological campsites (12,800 to 11,200 cal BP) show that trees were key features in the creation of everyday habitats for the first inhabitants of the Atacama Desert. At two of these sites, QM12 and QM35, the spatial and chronological correlation between trees and hearths reveals that people located their homes under the tree canopy. At residential site QM35, artifact distribution coincides with a grove dated to ~11,600 to 11,200 cal BP. A third residential area (QM32) occurred along the grove margins ~12,000 to 11,200 cal BP. Based on the distinct cultural material of these two camps, we propose that two different groups intermittently shared this rich wetland-grove environment. The tree taxa suggest a preference for the native
Schinus molle,
a tree scarcely present on the landscape today, over the endemic, nitrogen-fixing
Strombocarpa tamarugo
, both for toolmaking and firewood and even though the
S. tamarugo
was locally more abundant. Together with the spatial and chronological coincidence of campsites, hearths, and trees, we propose that people spared the most abundant and resilient species to create their homes, in turn promoting fertility oases amid the Atacama’s hyperaridity.
Influence of sawtooth oscillations on fast ions in a stellarator
Authors: Moseev D. , Zanini M. , Kasahara H. , Laqua H.P. , Funaba H. , Hayashi W.H.J. , Heidbrink W. , Ida K. , Igami H. , Kawamoto Y. , Kenmochi N. , Lazerson S.A. , Nishiura M. , Ochoukov R. , Ogawa K. , Rud M. , Salewski M. , Seki T. , Tamura N. , Tanaka K. , Tokuzawa T. , Yoshinuma M.
Published: April 2024

Sawtooth oscillations in tokamaks frequently lead to the redistribution of energetic ions, mainly on passing orbits, causing their expulsion from the core. This paper discusses the first measurements of the interaction of fast ions and sawteeth in the Large Helical Device. The crashes were caused by the plasma current induced by Electron Cyclotron Current Drive and Neutral Beam Current Drive. Despite these crashes, there was no detectable redistribution effect on fast ions in either the core or at the edge of the plasma.
Multi-core shared tree based MP2MP RWA algorithms in large scale and multi-domain optical networks
Authors: Xiao Zhanding , Zheng Bo , Xia Jinghui , Zhao Zongqu
Published: April 2024

The increasing demands of bandwidth-intensive parallel computing and collaborative applications, efficient service provisioning to support multipoint to multipoint (MP2MP) communications have attracted increasing attention. However, with the development of larger-scale and multi-domain optical networks, MP2MP RWA are introduced optimal domain sequence selection and core nodes belong to which domains problems which cannot be tackled by the conventional algorithms proposed aim at a signal domain. In this paper, we proposed a multi-core node shared multicast tree heuristic algorithm (MCSMT) which calculation could be parallelized, delay and minimal cost constrained for multi-domain optical networks. It could realize the accurate calculation of minimum number of cores and the hosted domains of the cores. The source and destination nodes were added in different shared trees respectively with delay constrained algorithms according to specific QoS selection strategy. At the same time, according to more complicated MP2MP algorithms we propose a PCE-cloud based control architecture for optical networks by applying the cloud computing technology (e.g. virtualization and parallel computing) to reform the control plane for improving system reliability, intelligence and maximizing resource utilization. The performances of the proposed heuristic with regard to the number of multi-core nodes, wavelength channel occupied and MP2MP setup latency are compared. In addition, the performance about path computing latency for PCE-cloud control architecture is compared with conversional control architecture.
Research on Intelligent Supervision System and Terminal for Small Sluice Group
Authors: Shen Bing , Tu Jiajia , Wang Changguo , Huang Xiaobin , Zhang Yongchao , Xiang Weihua
Published: April 2024

As a conventional water conservancy project, small water gates play a crucial role in flood prevention and drainage, water storage and irrigation. In response to the problems of a large number, wide distribution, and difficult management of small water gates, this article proposes an intelligent supervision system for small water gate groups based on the three-level architecture of provinces, cities, and counties. Then, according to the requirements of small water gate supervision, the hardware circuit and software program of the monitoring terminal were specially designed. The main content of this article includes three aspects: the provincial, city, and county level design of regulatory platforms, the modular and hierarchical structure design of terminal hardware, and the standardization and standardization design of terminal software. It provides a solution for the intelligent, efficient, and standardized management of small water gate groups, as well as a low-cost, reliable, and versatile monitoring terminal for the implementation of the solution. It has positive significance in solving the management difficulties of small water gates.
All-in-SAM: from Weak Annotation to Pixel-wise Nuclei Segmentation with Prompt-based Finetuning
Authors: Cui Can , Deng Ruining , Liu Quan , Yao Tianyuan , Bao Shunxing , Remedios Lucas W. , Landman Bennett A. , Tang Yucheng , Huo Yuankai
Published: April 2024

The Segment Anything Model (SAM) is a recently proposed prompt-based segmentation model in a generic zero-shot segmentation approach. With the zero-shot segmentation capacity, SAM achieved impressive flexibility and precision on various segmentation tasks. However, the current pipeline requires manual prompts during the inference stage, which is still resource intensive for biomedical image segmentation. In this paper, instead of using prompts during the inference stage, we introduce a pipeline that utilizes the SAM, called all-in-SAM, through the entire AI development workflow (from annotation generation to model finetuning) without requiring manual prompts during the inference stage. Specifically, SAM is first employed to generate pixel-level annotations from weak prompts (e.g., points, bounding box). Then, the pixel-level annotations are used to finetune the SAM segmentation model rather than training from scratch. Our experimental results reveal two key findings: 1) the proposed pipeline surpasses the state-of-the-art methods in a nuclei segmentation task on the public Monuseg dataset, and 2) the utilization of weak and few annotations for SAM finetuning achieves competitive performance compared to using strong pixelwise annotated data.
Recent University Research, Implementation and Education in Support of Pyrometallurgical Lead Processing
Authors: Jak Evgueni , Shevchenko Maksym , Shishin Denis , Nekhoroshev Evgenii , Starykh Roman , Chen Jiang , Hayes Peter
Published: April 2024

The increasing chemical complexity of lead process streams encountered in industrial high temperature processing operations, as the result of declining primary resources, increased metal recycling and increased overall range of metals in modern devices has highlighted the urgent need for new predictive tools, fundamental phase equilibria and thermodynamic information and thermodynamic models to characterise the chemical behaviour of these systems. The paper examines recent progress in experimental and thermodynamic modelling research on process fundamentals, the availability of advanced, predictive computer-based tools and the implementation of the research outcomes into industrial practice. A wide range of chemical systems and phase assemblages have been studied. Some examples are taken from the current research program at PYROSEARCH, which involves the characterisation of multi-component, multi-phase gas-slag-matte-speiss-metal-solids systems with the PbO-ZnO-“Cu2O”-FeO-Fe2O3-CaO-Al2O3-MgO-SiO2-S as major and As-Sn-Sb-Bi-Ag-Au-Ni-Co-Cr-Na as minor elements with focus on systems directly relevant to lead primary and recycling pyrometallurgical processes. Examples of the application of advanced analytical techniques to fundamental and applied industrial research are also given. The implementation of new research outcomes into industrial practice depends critically on commitments by research staff as well as industry management and the availability of well-trained metallurgical engineers. We examine the current status of research implementation, university research, metallurgical engineering education and the availability of suitable educational pathways and initiatives that can be taken to increase undergraduate enrolments. Active engagement and support by industry is critical in ensuring the continuation of academic programs and advanced technical skills required by the industry.
Analysis of bioleaching characteristics and multi-element dissolution behavior of complex zinc ores
Authors: Li Jiafeng , Qiu Xuemin , Qiu Xiaobin , Zhou Guili
Published: April 2024

In order to recover low-grade complex zinc ore in a reasonable way, this study adopts bioleaching method to study it. The ore samples contain 1.52%, 2.03% and 14.4% zinc, respectively, which occurs in the form of sphalerite. Other major minerals include pyrite, galena, quartz and mica. The inoculation of the domesticated strain was basically free of adaptation period, and the cell concentration could be rapidly increased after a short decrease. The leaching extent of zinc increased continuously, while the leaching rate decreased gradually. After the bioleaching process, sliver, lead and iron were mainly present in the residue phase. X-ray diffraction spectroscopy analysis showed that sphalerite, galena and pyrite were dissolved, and the latter two further precipitated to produce PbSO4 and jarosite. In addition, the dissolution of calcium compounds can lead to the formation of gypsum precipitation. These precipitates covered the fresh ore surface may hinder the further bioleaching process. The Exponential model was used to simulate the bioleaching process, and it was found that the fit coefficients were all greater than 0.98, and a reasonable leaching cycle was further discussed. The results provide a good basis for the economic and environmentally friendly recovery of low-grade complex zinc ores.
Recycling potential of secondary zinc materials
Authors: Leeuwen Martin van , Gay Bruno , Grund Sabina
Published: April 2024

Circularity is a decisive corner stone of a sustainable use of raw materials. This has been recognized at global level and is pushed forward specifically in Europe and e.g., Japan. Based on intensive desk top research and interviews with experts from the zinc industry, information on secondary raw materials for zinc recovery was compiled. This paper comprises of an overview of zinc bearing wastes, residues, and by-products occurring in all stages of zinc mining, production, as well as first-use and end-use production. These materials are quantified and characterized, and ways of recycling are described.

As a result, potentials for an increase of zinc recycling rates are identified. Mine tailings are a meaningful resource for zinc recovery. Industrial wastes occurring in zinc smelters, such as Jarosite, Goethite, and their likes are in the scope of research projects aiming at recycling zinc and other valuable metals. Residues, ashes, drosses, slags that are produced in first use operation of the zinc value chain, such as galvanizing, zinc die casting, or brass plants are recycled almost completely in Europe and in many other regions in the world. The biggest potential for increasing recycling rates for zinc still lies in steel mill dusts. Also, the majority of zinc die cast parts seem to end up in waste incineration and dump sites. This low end-of-life zinc recycling rate bears room for additional recycling opportunities via an improvement of the intelligent collection and sorting of waste and other innovative recycling processes utilizing residues from waste-to-energy plants.
Production increase of high-grade crude zinc oxide pellets at Shisaka Smelting Co., Ltd.
Authors: Egawa S. , Takaya S. , Yamamoto K. , Fujiyama H.
Published: April 2024

Shisaka Smelting Co., Ltd. has recovered crude zinc oxide pellets from an electric arc furnace dust (EAF dust) by the Waelz kiln process since 1977. The EAF dust processing line consists of a reduction roasting process, a Waelz oxide washing process, and a drying/calcination process. In late years, about 90,000 tons of EAF dust is processed annually at Shisaka. The recovered zinc is sold to zinc smelters as crude zinc oxide pellets, and the amount of production of the pellets is about 40,000 tons per year. Two types of zinc oxide pellets are produced, and the product for electro-refinery requires high quality, especially in fluorine reduction. Most of fluorine are distributed to the clinker in a reduction roasting process, and others are distributed to the Waelz oxide. Conventionally, high-grade crude zinc oxide pellets were produced by washing the Waelz oxide and by volatilizing and separating fluorine under high temperature operation in a drying rotary kiln. However, formation of accretion in the kiln and damage of the shell and refractories of the kiln often occurred under the influence of high temperature operation, and stable consecutive operation of the kiln was difficult.

To improve this situation, the fluorine input was reduced by compounding management of EAF dust in the reduction roasting process, and the material residence time in the drying rotary kiln was extended by reducing rotary speed. These improvements resulted in stable consecutive operation under low temperature conditions and increased production of high-grade crude zinc oxide pellets. To improve this situation, the fluorine input was reduced by compounding management of EAF dust in the reduction roasting process, and the material residence time in the drying rotary kiln was extended by reducing rotary speed. These improvements resulted in stable consecutive operation under low temperature conditions and increased production of high-grade crude zinc oxide pellets.
The phase structure, transitions, and non-isothermal crystallization kinetics of Zn2V2O7 glass
Authors: Li Zhuoyang , Pei Guishang , Jiao Mengjiao , Li Yongda , Zhang Ningyu , Lv Xuewei
Published: April 2024

The Zn2V2O7 glass was prepared by solid-state reaction using the initial reactant ZnO and V2O5 powder. X-ray diffraction was employed to characterize the phase composition of the as-prepared Zn2V2O7 powder. The crystallization kinetics of Zn2V2O7 glass prepared by solid-state reaction was studied using differential thermal analysis under non-isothermal conditions. It was established that the crystallization process of Zn2V2O7 can be divided into two steps, which is controlled first by a Disc-like with kinetic equation G(α)=[-ln(1-α)]1/3
and then by a Fibril-type growth type with kinetic equation G(α)=[1-(1-α)1/3]1/2
. The apparent activation energy calculated by different methods (Kissinger method, Ozawa method, Tang method, and Starink method) under non-isothermal conditions were similar, varying between 335.6 kJ·mol−1 and 371.6 kJ·mol−1, and the average apparent activation energy was equal to 362.2 kJ·mol−1.
Formation and propagation characteristics of pseudo-wavefronts of optical polarization states signal inside OPGW under lightning strikes
Authors: Zhao Mengshi , Li Tao , Yin Qi , Fu Shijie , Wei Wei
Published: April 2024

Lightning strikes on Optical Fiber Composite Overhead Ground Wires (OPGW) result in a phenomenon where the current traveling wave along the OPGW’s outer stranding propagates faster than the optical signals inside the fiber. This leads to the emergence of pseudo-wavefronts ahead of the optical polarization state signal after lightning strikes OPGW, introducing errors in lightning point localization based on the optical polarization state. This paper investigates the formation and propagation characteristics of pseudo-wavefronts. The study employs theoretical analysis and simulation to examine the process of optical polarization state formation during OPGW lightning strikes. Additionally, it conducts comparative analyses between laboratory-simulated OPGW lightning strikes and field measurements obtained from OPGW lightning monitoring systems. The results affirm the existence of the proposed pseudo-wavefront phenomenon, which substantially impacts the precision of lightning point localization. Notably, the duration of pseudo-wavefront effects increases with greater distance from the lightning point and higher lightning current amplitudes. These findings raise questions regarding the suitability of traditional wavefront calibration methods based on the traveling wave approach. This research contributes valuable insights for the practical implementation of lightning point localization methodologies relying on OPGW self-sensing technology.
CFD analysis of the complex japanese pufferfish nest
Authors: Dai Jialan , Zare-Behtash Hossein , Dai Chuanbo
Published: April 2024

Existing research on the pufferfish species (Torquigener Albomaculosus) has shown that its nest structure has a certain impact on flow velocity. This study aims to investigate the nest-building behavior by using different materials. A 3D model will be created based on nest geometry, and 2D simulations will be conducted by using computational fluid dynamics (CFD). Furthermore, the study examines the nest’s fluid dynamics characteristics in its original state, with varied materials and heights. Results demonstrate that the nest reduces flow velocity, adapts to external flow conditions, and enhances shear strength with rough materials. Additionally, nest height affects internal circulation area and pressure. This unique structure protects the spawning area, improves oxygen transport, and strengthens the nest. The study further expands biomimetic engineering applications and suggests future interdisciplinary research directions.
Multi-Objective set point optimization control of grate cooler considering energy efficiency evaluation
Authors: Chen Wei , Liu Yong , Ye Lei , Tao Jie , Chu Biao , Zhang Hongtu
Published: April 2024

The grate cooler is a key piece of equipment for cooling cement clinker, whose parameter adjustment has a notable influence on energy consumption and equipment operation. This article proposes a multi-objective set-point optimization control method for the grate cooler control system, which takes into account energy efficiency evaluation. Based on the energy efficiency analysis of the grate cooler, the secondary air temperature, tertiary air temperature, and outlet clinker temperature are used as energy efficiency evaluation indicators, and a grate cooler energy efficiency evaluation model is established to construct a multi-objective function. After that, the grate pressure set point and fan current set point are optimized by utilizing the MOEA/D algorithm, and the predictive control method is combined to perform rolling optimization of the control parameters. Eventually, a simulation experiment is conducted based on the actual production data, and the simulation results demonstrate the feasibility and effectiveness of the optimized control method.
Research on optimal power flow of AC/DC hybrid system for civil more electric aircraft
Authors: An Wenjing , Yang Yuanchao , Wu Geyi
Published: April 2024

Modern civil more electric aircraft often use AC/DC systems instead of AC systems to reduce the weight of the power system. Compared with the AC/DC system of the land power grid, the aircraft power system needs to pursue economic operation mode under more complex security constraints. This paper establishes the optimal power flow model of the AC/DC hybrid system of more electric aircraft, which takes minimizing the active power loss of the line as the optimization objective, including the steady-state operation constraints and security constraints of the AC/DC system. The interior point method and prediction correction interior point method are used to solve the model. Then, based on the simplified steady-state model of the B787 power system, the model and algorithm are verified by experiments. The experimental results show that by optimizing the power flow distribution of the power system, the power utilization efficiency of the system has been significantly improved, and its stability and reliability can also be better guaranteed.
Short-term load prediction with LSTM and FCNN models Based on attention mechanisms
Authors: Song Xiaolei , Wang Zhijie , Wang Hong
Published: April 2024

To address the significant load prediction discrepancies in microgrid economic dispatch, which result from substantial load fluctuations, a method for near-term load forecasting leveraging the attention mechanism is proposed, utilizing both LSTM and FCNN models. In this method, the attention mechanism is introduced to enhance the LSTM model’s ability to recognize and utilize key information, and the LSTM is used to process historical load data with time continuity selected by a sliding window, whereas the FCNN is used to process daily static features, such as the day’s maximum temperature, minimum temperature, and weather conditions. The outputs of the two networks are subsequently fused into a fully connected layer to generate the final load forecast. Training leverages six months of actual power load values and regional meteorological factor data. The forecast outcomes are then evaluated against both traditional and machine learning algorithms. The experimental findings highlight the superior prediction accuracy of the proposed model.
Design of planar comb-driven MEMS torsional mirror
Authors: Nie Shengwei , Zhai Leiying , Zhao Liyu
Published: April 2024

The MEMS torsional mirror is an important MEMS optical device, and its related applications are very wide, including LiDAR, projection equipment, optical communication, and so on. At present, the electrostatically driven MEMS torsional mirror mainly adopts a vertical comb driver to achieve torsional motion, which has some disadvantages such as a complicated manufacturing process, low yield, and high driving voltage. In this paper, a novel MEMS torsional mirror structure is proposed, which provides flexible elastic constraint points for the torsional mirror with the bottom support rod structure as the center, and relies on the combination of planar comb and support rod to form a tie rod structure to achieve torsion, and achieves a torsion Angle of ±15.55° under the driving voltage of 65 V. The use of a planar comb instead of a vertical comb greatly reduces the difficulty of manufacturing. Finally, it is verified that the system stability is good, the correlation drift does not affect the results within the range, the fifth-order modes are within the reasonable range, and the maximum stress is 671 MPa, which is controlled within the range of fracture stress of silicon material.
Preparation of fine-grain aluminum alloy by spinning method and its corrosion resistance test
Authors: Yu Yang
Published: April 2024

Due to the lack of shear resistance, the implanted materials in the aluminum alloy will lead to obvious wear. The emergence of fine-grained aluminum alloy materials can perfectly solve the above problems. Therefore, in this paper, the fine-grain aluminum alloy material is prepared by the spinning method, and the corrosion resistance test is carried out. The experimental results show that there is no significant difference in weight loss and surface morphology between aluminum alloy and fine-grain aluminum alloy immersed in normal saline and D-Hand’s solution for 30 days. The experimental results show that the fine-grained aluminum alloy has the basic conditions for in vivo implantation, which lays a foundation for the development of a new generation of in vivo implantation materials.
Optimization of swash plate multistage compressor based on dynamics
Authors: Liu Yongguang , Tong Saisai , Gao Xiaohui
Published: April 2024

The swash plate compressor can provide high-pressure gas through multistage compression using its different cylinders, which is an ideal structure for high-pressure compressor miniaturization. The swash plate multistage compressor (SPMC) with variable sections cylinder and inter-stage cooler is proposed and its complex structure results in complex multi-body dynamics and thermodynamics. To research the dynamic characteristics of SPMC, the dynamic model of SPMC is established, which includes the thermodynamics of compression and inter-stage cooler and the dynamics of all the check valves and pistons. The optimization objective function considering the dynamic characteristics and efficiency is proposed. The constraint conditions and sensitivity of the optimized parameters are studied and the final parameters are achieved through an optimization algorithm. Based on the above work, it can be found that the optimization way has high convergence and accuracy, and the comprehensive performance of SPMC is improved significantly.
Modeling method study for transfer matrix of space rigid bodies supported by multiple elastic hinges
Authors: Lu Zhaogang , Qian Dashuai , Kang Weijia , Lu Minyue , Lu Yang
Published: April 2024

When rigid bodies as well as elastic hinges connected are modeled by using a transfer matrix method, they need to be defined as multi-input and multi-output space rigid bodies, resulting in higher dimensions of the whole transfer matrix and complexity of modeling. To reduce the dimensions of the whole matrix and improve computational efficiency and accuracy, the elastic hinges and the rigid bodies are integrated into a unified model in this paper. Then a single 12×12 matrix is obtained through theoretical derivation. The resulting transfer matrix of space rigid bodies supported by multiple elastic hinges not only reduces the dimensions of the whole matrix but also simplifies the configuration of the transfer matrix model by which some tree-like systems can be simplified into chain-like systems. Subsequently, the effectiveness of the matrix is validated through computational comparative analysis of typical systems. The modeling method is an important optimization to the calculation method of the dynamics characteristics of the transfer matrix.
Design and optimization of liquid-cooled plate structure for power battery of the pure electric excavator
Authors: Chen Yunfan , Zhao Hongqiang , Liu Qiang
Published: April 2024

With the increasing pressure of energy transformation and environmental protection, the trend of electrification of construction machinery is becoming more and more obvious. In this paper, based on a small pure electric excavator which is still in the stages of research and development, a liquid-cooled heat dissipation structure (liquid-cooled plate) is designed according to the power battery pack scheme. The overall shape of the liquid-cooled plate is designed as a symmetrical serpentine flow channel. Geometrically, the symmetrical serpentine flow channel is a combination of a straight flow channel and a runway-shaped flow channel. Then the conjugate heat transfer simulation model was established by using the CFD software Ansys Fluent. The results show that the initial scheme can not guarantee the temperature homogeneity of the battery pack. Therefore, the liquid-cooled heat dissipation scheme was optimized and compared. Firstly, a liquid-cooled plate was added on the original basis, and multiple sets of simulations were carried out with the length of the linear flow channel as a variable. The results show that appropriately increasing the length of the straight flow channel at the entrance of the liquid-cooled plate has a marked effect on improving the heat dissipation performance.
Control strategy for power factor correction circuits based on model predictive control
Authors: Wang Shu , Xu Xiaohui , Song Tao , Li Xizhe , Zhu Weilong
Published: April 2024

Power factor correction circuits are being used more extensively, and with that, the requirements and standards have become increasingly stringent. To improve the power factor of the circuit, thereby improving its operational efficiency and mitigating the load effects in boost power factor correction circuits, reducing Total Harmonics Distortion is crucial for improving the quality of the current. An improvement upon the conventional dual-loop PID control algorithm has been proposed. It involves integrating Model Predictive Control into the current loop design and incorporates a Luenberger observer. Model Predictive Control methods can be applied for the control of multivariable systems, especially in complex multivariable systems, as they exhibit strong robustness. Finally, by performing both simulation and experimental validations and analyzing the data results, it is shown that under full load conditions, the power factor λ is 0.968, the efficiency η is 91.11%, the voltage total harmonic distortion Uthd
is 1.88%, and the current total harmonic distortion Ithd
is 7.04%. These data results strongly confirm the performance of the control mechanism proposed in this paper.
Study of distribution network loss allocation with high photovoltaic penetration ratio
Authors: Chen Yun , Li Yadi , Liu Jilei , Liu Shipeng , Zhang Jie , Ma Yongfei , Pan Ziyan , Ge Yimeng , Lu Binxian
Published: April 2024

With the rapid development of renewable energy, the penetration ratio of photovoltaic (PV) in the distribution network is getting higher and higher. The fair and reasonable allocation of high loss caused by high PV penetration in the distribution network is of great significance to the healthy development of distribution systems. In order to study the loss allocation in distribution networks with high PV penetration, based on the cooperative game theory, combined with the power flow algorithm, the power flow and loss of the 72-node active distribution network in agricultural and pastoral areas were analyzed. Three scenarios were included: no PV, low PV penetration, and high PV penetration. The allocated loss of the distribution network with high PV penetration and multiple distributed generators was computed. The results show that the loss allocation method, which takes into account the power as well as the network topology, is applicable to distribution networks with multiple distributed generators. In distribution networks with high PV penetration, distributed generators are the main cause of high loss. If the network contains the extreme reverse power flow concerned in this paper, the loss allocated to DGs accounts for more than 95% of the total network power loss.
Off-line location strategy for single-phase ground fault of distribution line
Authors: Li Shengzhu , Yang Ming , Zhao Bing , Huang Yining , Zheng Zimo
Published: April 2024

This paper adopts off-line location strategy of single-phase grounding fault of distribution lines, determines size and frequency of injected AC signal by analyzing distribution parameters of lines, and then develops portable small current signal source with adjustable frequency through power conversion control technology, and develops signal detector by analyzing noise correlation and adaptive morphological filtering. Then off-line location strategy is developed according to above two signal devices. Finally, it is verified that the strategy can accurately locate fault point of distribution line.
Diffusive shock acceleration in relativistic, oblique shocks
Authors: Marle Allard Jan van , Bohdan Artem , Araudo Anabella , Casse Fabien , Marcowith Alexandre
Published: April 2024

Cosmic rays are charged particles that are accelerated to relativistic speeds by astrophysical shocks. Numerical models have been successful in confirming the acceleration process for (quasi-)parallel shocks, which have the magnetic field aligned with the direction of the shock motion. However, the process is less clear when it comes to (quasi-)perpendicular shocks, where the field makes a large angle with the shock-normal. For such shocks, the angle between the magnetic field and flow ensures that only highly energetic particles can travel upstream at all, reducing the upstream current. This process is further inhibited for relativistic shocks, since the shock can become superluminal when the required particle velocity exceeds the speed of light, effectively inhibiting any upstream particle flow. In order to determine whether such shocks can accelerate particles, we use the particle-in-cell (PIC) method to determine what fraction of particles gets reflected initially at the shock. We then use this as input for a new simulation that combines the PIC method with grid-based magnetohydrodynamics to follow the acceleration (if any) of the particles over a larger time-period in a two-dimensional grid. We find that quasi-perpendicular, relativistic shocks are capable of accelerating particles through the DSA process, provided that the shock has a sufficiently high Alfvénic Mach number.
Ookami: An A64FX Computing Resource
Authors: Calder A C , Siegmann E , Feldman C , Chheda S , Smolarski D C , Swesty F D , Curtis A , Dey J , Carlson D , Michalowicz B , Harrison R J
Published: April 2024

We present a look at Ookami, a project providing community access to a testbed supercomputer with the ARM-based A64FX processors developed by a collaboration between RIKEN and Fujitsu and deployed in the Japanese supercomputer Fugaku. We provide an overview of the project and details of the hardware, and describe the user base and education/training program. We present highlights from previous performance studies of two astrophysical simulation codes and present a strong scaling study of a full 3D supernova simulation as an example of the the machine’s capability.
Quasi all-speed schemes for magnetohydrodynamic flows in a wide range of Mach numbers
Authors: Minoshima Takashi
Published: April 2024

We present novel numerical schemes for ideal magnetohydrodynamic (MHD) simulations aimed at enhancing stability against numerical shock instability and improving the accuracy of low-speed flows in multidimensions. Stringent benchmark tests confirm that our scheme is more robust against numerical shock instability and is more accurate for low-speed, nearly incompressible flows than conventional shock-capturing schemes. Our scheme is a promising tool for tackling MHD systems, including both high and low Mach number flows.
Low-regularity exponential-type integrators for the Zakharov system with rough data in all dimensions
Authors: Li Hang , Su Chunmei
Published: April 2024

We propose and analyze a type of low-regularity exponential-type integrators (LREIs) for the Zakharov system (ZS) with rough solutions. Our LREIs include a first-order integrator and a second-order one, and they achieve optimal convergence under weaker regularity assumptions on the exact solution compared to the existing numerical methods in literature. Specifically, the first-order integrator exhibits linear convergence in
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="upper H Superscript m plus 2 Baseline left-parenthesis double-struck upper T Superscript d Baseline right-parenthesis times upper H Superscript m plus 1 Baseline left-parenthesis double-struck upper T Superscript d Baseline right-parenthesis times upper H Superscript m Baseline left-parenthesis double-struck upper T Superscript d Baseline right-parenthesis">

H

m
+
2

(

T

d

)
×

H

m
+
1

(

T

d

)
×

H
m

(

T

d

)

H^{m+2}(\mathbb {T}^d)\times H^{m+1}(\mathbb {T}^d)\times H^m(\mathbb {T}^d)

for solutions in
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="upper H Superscript m plus 3 Baseline left-parenthesis double-struck upper T Superscript d Baseline right-parenthesis times upper H Superscript m plus 2 Baseline left-parenthesis double-struck upper T Superscript d Baseline right-parenthesis times upper H Superscript m plus 1 Baseline left-parenthesis double-struck upper T Superscript d Baseline right-parenthesis">

H

m
+
3

(

T

d

)
×

H

m
+
2

(

T

d

)
×

H

m
+
1

(

T

d

)

H^{m+3}(\mathbb {T}^d)\times H^{m+2}(\mathbb {T}^d)\times H^{m+1}(\mathbb {T}^d)

if

m
>
d

/

2

m>d/2

, meaning that only the boundedness of one additional derivative of the solution is required to achieve the first-order convergence. While for the second-order integrator, we show that it achieves second-order accuracy by requiring the boundedness of two additional spatial derivatives of the solution. The order of additional derivatives required is reduced by half compared to the classical trigonometric integrators. The main techniques to design the integrators include a reformulation by introducing new variables to exclude the loss of spatial regularity in the original ZS, accurate integration for the dominant term in the linear part of the equations and appropriate approximations (or averaging approximations) to the exponential phase functions involving the nonlinear interactions. Numerical comparisons with classical integrators confirm that our newly proposed LREIs are superior in accuracy and robustness for handling rough data.
Simultaneous Rhinoplasty and Septal Perforation Repair Using the Bone-Cartilaginous Unit
Authors: Sazgar Amir A , Sazgar Mehr A , Zarringhalam Mohammad A , Sazgar Amir K
Published: April 2024

Background

Various techniques are employed for septal perforation repair but success rates still vary. Numerous mucosal flaps are used for septal perforation closure; however, a scaffold is essential for proper positioning and enhanced mucosal growth.

Objectives

The aim of this study was to assess the effectiveness of utilizing a septal bone/cartilage composite graft (BC unit) to close septal perforations in rhinoplasty patients and evaluate patient satisfaction.

Methods

This case series included patients with septal perforation undergoing rhinoplasty and perforation repair between 2019 and 2023. BC units were used to cover the cartilaginous perforations in all patients. Patients were followed for a minimum of 1 year, assessing surgical results and postoperative satisfaction with the 10-item Standardized Cosmesis and Health Nasal Outcomes Survey (SCHNOS).

Results

In this study, 31 patients (22 female, 9 male), with a mean [standard deviation] age of 34.80 [10.31] years (range, 19-59 years), were enrolled. Nine had previousl undergone septoplasty, while four had undergone septorhinoplasty. The preoperative perforation size ranged from 6 to 27 mm (mean, 14.1 mm). At final follow-up, 26 cases (83.8%) achieved complete closure, while 3 had incomplete closures, and 2 experienced reperforation. Analysis revealed a notable mean decrease of 31.93 [26.47] in obstruction domain scores (SCHNOS-O) and a mean decrease of 44.19 [25.37] in cosmesis domain scores (SCHNOS-C).

Conclusions

Septal perforation repair and rhinoplasty can be safely and effectively performed concurrently with BC units for suitable candidates.

Level of Evidence: 3
Dynamic dichromatism and effects of high temperatures on male coloration plasticity in an ectotherm model
Authors: Rossi Nicola , Chiaraviglio Margarita , Cardozo Gabriela
Published: April 2024

Climate change is increasing the temperatures of wild environments, but the impacts on evolutionary ecological processes, such as sexual selection, are still under-studied. In ectotermic tetrapods, male coloration is a pivotal trait in social contexts. During the reproductive season, males can enhance the dichromatic coloration of certain body regions. However, it is unknown how reproductive dichromatism might interact with the increasing temperatures that cause body temperatures to fall within the upper range of preferred temperatures. We hypothesize that sexual dichromatism could be dynamic, i.e. show changes, being reinforced during the reproductive period of the species. However, high temperatures associated with climate change could disrupt reproductive colour patterns by inducing plastic changes. We test this in the social lizard species Tropidurus spinulosus in a laboratory setting by applying three thermal treatments: one reproducing current thermal conditions and two simulating scenarios of climate change. Our results highlight that male coloration is enhanced during the reproductive season in key body regions for social displays. At the preferred temperature of the species, males could darken their ventral coloration; however, no such change was observed at high temperatures. Therefore, increasing temperatures could impact the capacity of males to adjust their coloration plastically during the reproductive season.
One more word on Patagonian Ulota macrodontia: Ulota brachypoda sp. nov. (Orthotrichaceae, Bryophyta)
Authors: Matanov Nikolay , Draper Isabel , Calleja Juan Antonio , Flagmeier Maren , Lara Francisco , Garilleti Ricardo
Published: April 2024

The bryophyte genus Ulota has its main diversification area in Patagonia, with 18 currently accepted species, all of which are endemic to the area. Despite this richness, ongoing studies indicate the existence of hitherto unknown species in this territory. However, the strong resemblance between species often complicates the discrimination of new taxa, making the use of integrative taxonomy approaches compulsory. During surveys conducted in past decades, a morphotype of a Ulota, closely resembling Ulota macrodontia, was discovered coexisting with this species. Ulota macrodontia is characterized by unique peristomial features within the genus, and the variant morphotype shares these characteristics while displaying some distinct gametophytic and sporophytic features. Biometric analyses demonstrate that the differences are stable, and without intermediate states. The results obtained from the analyses of one nuclear and four plastid loci reveal a close relationship between both morphotypes, with the samples of U. macrodontia forming a well-supported monophyletic group. We propose to treat the new morphotype at species level (Ulota brachypoda sp. nov.), discussing why this is the most appropriate taxonomic rank, and we provide a detailed and illustrated description. Additionally, a distribution map of the two endemics is included.