bluuebunny/crossref_metadata_2025_split huggingface dataset:
20.5.1.7.16 Catalytic α-Arylation of Alkyl Alkanoates
Authors: Liao L. , Zhang Y. , Yu J.-S. 
Published: February 2025

Abstractα-Aryl carboxylic esters are important motifs or precursors in a wide variety of drugs, bioactive natural products, and pharmacologically active compounds. This chapter is an update to enrich the original Science of Synthesis chapter dedicated to the synthesis of alkyl alkanoates “Synthesis with Retention of the Functional Group” (Section 20.5.1.7). The current review focuses on recent advances in the catalytic α-arylation of alkyl alkanoates, and describes methods for the synthesis of α-aryl carboxylic compounds reported in the period 2001–2022. Seven main approaches are introduced: α-arylations of alkyl esters or their enolates, α-arylations of Reformatsky reagents with aryl halides, α-arylations of silyl ketene acetals, α-arylations of α-halo esters, α-arylations of α-diazo esters, decarboxylative or deacetylative α-arylation of β-carbonyl esters, and reductive C—O bond arylation of oxalates derived from α-hydroxy esters.
Graphene microelectrodes for real-time impedance spectroscopy of neural cells in organ-on-a-chip
Authors: Ouedraogo Lionel Jean Gabriel , Kling McKayla , Hashemi Nicole N. 
Published: February 2025

This study presents the development and characterization of a graphene-based sensor integrated into a microfluidic chip for real-time monitoring of cell growth and viability in an organ-on-a-chip platform. The sensor fabrication involved the metabolization of graphene from graphite using a simple and cost-effective method. The sensor design, created using SolidWorks, featured electrodes capable of detecting environmental changes through impedance sensing. A mold was created using a cutter plotter to overcome challenges in achieving the desired sensor shape, and the graphene electrodes were then printed on a polyester (PETE) membrane. The conductivity of the electrodes was optimized through annealing, by considering the temperature limits of the membrane. Annealing at 150 °C for 40 min yielded electrodes with the desired conductivity while maintaining membrane integrity. The annealing parameters were confirmed through cell culture experiments for compatibility with cellular growth. The scaled electrodes were integrated into a microfluidic chip, and their performance was evaluated using cyclic voltammetry and electrochemical impedance spectroscopy. The results demonstrated the successful functioning of the electrodes within the chip. The developed graphene-based sensor offers promising applications in other organ-on-a-chip studies, as well as in cellular studies and biosensing, through real-time monitoring of cell growth and viability that was achieved by measuring impedance changes resulting from cell attachment.
A population viability analysis of K’gari (Fraser Island) wongari (dingoes)
Authors: Appleby Robert , Smith Bradley P. , Jones Darryl , Conroy Gabriel , Behrendorff Linda 
Published: February 2025

Small, isolated populations such as those found on islands are at an increased risk of extinction. This includes K’gari (Fraser Island) wongari (dingoes). Although aspects of wongari ecology and behaviour are well documented, much about population dynamics remains uncertain. Even where relevant research has been conducted (e.g. population abundance), results remain equivocal. We conducted a population viability analysis (PVA) to investigate the influence of different abundance estimates, along with variable rates of mortality, carrying capacity, catastrophes and breeding success on extinction probability. In favourable, undisturbed conditions, modelling showed a high probability of population persistence over 50 and 100 years. Consistently high levels of mortality resulted in increased extinction probabilities, especially at low- and mid-level population sizes. Promiscuous breeding behaviour, higher female breeding success, and higher male availability reduced extinction probabilities. Our approach demonstrated the utility of population viability analysis for identifying important factors that meaningfully contribute to wongari extinction risk. However, inferences and actionable recommendations for managers were limited owing to a paucity of information for certain, critical parameters. Our findings highlighted the need for better data on wongari reproduction and mortality to help fill significant knowledge gaps required to accurately predict the long-term survival of this iconic population.
Habitat for the endangered ephemeral Monotaxis macrophylla (Euphorbiaceae) in New South Wales: how do predictions compare with the evidence?
Authors: Bell Stephen A. J. 
Published: February 2025

Context The endangered ephemeral herb Monotaxis macrophylla (Euphorbiaceae) has limited (~211) records throughout its known range in eastern Australia. In New South Wales (NSW), the 127 occurrences are spread over more than half of the state, and for regulatory purposes this has led to 262 Plant Community Types (PCTs) being predicted as suitable habitat for the species in the BioNet Threatened Biodiversity Data Collection (TBDC). Under the Biodiversity Assessment Method currently in use in NSW, Monotaxis macrophylla is to be specifically addressed for any development site where one or more of the 262 PCTs occur. Aims To assess how predicted habitats for Monotaxis macrophylla as shown in the TBDC compare with evidence of occurrence. Methods Examination of all available voucher collections, observations records, and the literature for eastern Australia was undertaken, and reviewed against the New South Wales PCT classification. Key results Monotaxis macrophylla was found to be affiliated with only 15 PCTs in NSW at best, but only 10 of these are currently included in the list of predicted PCTs for the species. The weight of evidence from existing presence data clearly shows that 10 heath and rocky scrub PCTs identified for Monotaxis macrophylla in NSW comprise 121 (95%) of all NSW records. Analysis of records in Queensland against Regional Ecosystems did not identify additional PCT-affiliated vegetation that might also support the species elsewhere in NSW. Conclusions The revised suite of 15 PCTs known or expected to support Monotaxis macrophylla occupies just 14,660 km2 or 1.8% of the State (potentially less if low-confidence PCTs are removed), compared with more than 27,000 km2 or 3.4% for the predicted 262 PCTs. Implications Currently, if any development is proposed within land that supports one or more of the 262 PCTs linked to Monotaxis macrophylla, appropriately timed targeted surveys are required to discount its presence, or it must be assumed to be present. This review has highlighted that predicted habitats should be evidence based by using known presence data, rather than assumed using broad understandings of possible habitat, and regular revision of predicted habitats within regulatory frameworks for all threatened species is recommended.
A Link Between White Dwarf Pulsars and Polars: Multiwavelength Observations of the 9.36-minute Period Variable Gaia22ayj
Authors: Rodriguez Antonio C. , El-Badry Kareem , Hakala Pasi , Rodríguez-Gil Pablo , Bao Tong , Galiullin Ilkham , Kurlander Jacob A. , Law Casey J. , Pelisoli Ingrid , Schreiber Matthias R. , Burdge Kevin , Caiazzo Ilaria , Roestel Jan van , Szkody Paula , Drake Andrew J. , Buckley David A. H. , Potter Stephen B. , Gaensicke Boris , Mori Kaya , Bellm Eric C. , Kulkarni Shrinivas R. , Prince Thomas A. , Graham Matthew , Kasliwal Mansi M. , Rose Sam , Sharma Yashvi , Ahumada Tomás , Anand Shreya , Viitanen Akke , Wold Avery , Chen Tracy X. , Riddle Reed , Smith Roger 
Published: February 2025

Abstract
White dwarfs (WDs) are the most abundant compact objects, and recent surveys have suggested that over a third of WDs in accreting binaries host a strong (B ≳ 1 MG) magnetic field. However, the origin and evolution of WD magnetism remain under debate. Two WD pulsars, AR Sco and J191213.72–441045.1 (J1912), have been found, which are non-accreting binaries hosting rapidly spinning (1.97 minutes and 5.30 minutes, respectively) magnetic WDs. The WD in AR Sco is slowing down on a

P
/

P

̇

≈
5.6
×
1

0

6

yr timescale. It is believed they will eventually become polars, accreting systems in which a magnetic WD (B ≈ 10−240 MG) accretes from a Roche lobe-filling donor spinning in sync with the orbit (≳78 minutes). Here, we present multiwavelength data and analysis of Gaia22ayj, which outbursted in 2022 March. We find that Gaia22ayj is a magnetic accreting WD that is rapidly spinning down (

P
/

P

̇

=
6
.

1

−
0.2

+
0.3

×
1

0

6

yr) like WD pulsars, but shows clear evidence of accretion, like polars. Strong linear polarization (40%) is detected in Gaia22ayj; such high levels have only been seen in the WD pulsar AR Sco and demonstrate the WD is magnetic. High speed photometry reveals a 9.36 minutes period accompanying a high amplitude (∼2 mag) modulation. We associate this with a WD spin or spin–orbit beat period, not an orbital period as was previously suggested. Fast (60 s) optical spectroscopy reveals a broad “hump,” reminiscent of cyclotron emission in polars, between 4000 and 8000 Å. We find an X-ray luminosity of

L

X

=
2
.

7

−
0.8

+
6.2

×
1

0

32

ergs

−
1

in the 0.3–8 keV energy range, while two very large array radio campaigns resulted in a non-detection with a F

r
< 15.8 μJy 3σ upper limit. The shared properties of both WD pulsars and polars suggest that Gaia22ayj is a missing link between the two classes of magnetic WD binaries.
Energies of the strongly-dissipative quantum scalar field
Authors: Jafari Marjan 
Published: February 2025

Abstract
Dynamics and energies of a quantum dissipative scalar field at finite temperature and in strong-coupling regime are investigated. The Lagrangian of the total system is canonically quantized and symmetric correlation functions are obtained. To employ the thermo-field technique, the density operator of the strongly dissipative scalar field is introduced. Mean energy, internal energy, and thermally averaged energy of the system are calculated. Also, mean energy and internal energy are written in terms of probability distribution function in frequency domain that is shown the energy functions satisfy the quantum counterpart of the energy equipartition theorem. In the weak coupling regime, all the energy expressions reduce to

ℏ
ω

2

coth
⁡
(

ℏ
ω

2

K
B

T

)

, that is the familiar result.
Development of rust removal device for underground contact line in coal mine
Authors: Liu Yurong 
Published: February 2025

Abstract
In order to effectively solve the rust of rail catenary in underground coal mines, the advantages and disadvantages of physical rust removal, laser rust removal, and chemical rust removal are analyzed. The more suitable physical rust removal is selected. At the same time, the design requirements and functional requirements of the rust removal device are studied, and the rust removal device with automatic lifting, left and right offset compensation, and adjustable pressure is developed. The de-rusting work of the overhead contact line was successfully completed through the industrial test on-site, which verified the feasibility of the device, improved the efficiency of the dedusting of the overhead contact lines in the underground coal mines, and reduced labor intensity.
Research on fault diagnosis of the suspension gap sensor based on PBC-PCA-LSSVM
Authors: Tang Kaiyi , Di Yuanjian , Lv Gengchen , Jiang Yue 
Published: February 2025

Abstract
The suspension gap sensor is essential for the suspension control system of high-speed maglev trains. Its functional failure can have a significant impact on the stability of the suspension point. In the context of engineering applications, the limited number of samples and the high dimension of diagnostic data present a severe challenge to the real-time and accurate diagnosis of sensor malfunctions. To tackle this issue, this paper introduces a fault diagnosis method for the suspension gap sensor of maglev trains based on the point-biserial correlation (PBC), principal component analysis (PCA), and least squares support vector machine (LSSVM). Initially, the PBC and PCA methods are employed to process the monitoring data to reduce its dimension. Subsequently, the pre-processed data is imported into LSSVM for fault diagnosis, which enables the real-time identification of the fault status of the suspension gap sensor. The experimental results show that the proposed method is effective in accurately identifying the measurement faults of the suspension gap sensor while exhibiting a rapid inference speed in comparison to alternative models.
Influence of Variation in contact angle of porous surfaces with different particle stacks on the permeability properties of porous media
Authors: Hu Renfei , Wang Zixiong , Zhang Guotao , Wang Xiaoyi 
Published: February 2025

Abstract
The ease of fluid movement within porous media is characterized by its permeability performance, and this property has significant implications in soil hydrology and materials science. Porous media were built using various particle arrangements to examine the permeation performance of droplets in particle-stacked porous media. The COMSOL simulation program and the level set method (LS) were used to track changes in the two-phase interface during the droplet permeation process, allowing for the investigation of the effects of various contact angles on the permeation process of droplets on the porous media surface. It is discovered that in comparison to the porous media created by mixed in-line particle stacking, the deeper the penetration is and the better the droplet penetration performance is, the smaller the internal pores of the porous media model with in-line particle stacking is; in addition, when the contact angle varies between 30° and 60°, the droplet penetration performance is worse at 120° and better at 60°. A theoretical foundation for comprehending droplet permeation in porous media is provided by the findings.
Study on mechanical properties of two-dimensional roller cutter penetrating different particle systems
Authors: Zhang Yiwen , Liu Yuan , Lu Zhongshan 
Published: February 2025

Abstract
In order to study the mechanical properties of the disc cutter penetrating the particle system, a composite particle system model of the monodisperse particle system and soft and hard interlayered composite particle system was established based on the discrete element method, in which the monodisperse particle system was divided into hard particle system and soft particle system, combined with the complex network theory, and the crack propagation phenomenon and force chain were analyzed from the perspective of mesomechanics, and the distribution and evolution of the second invariant of stress and stress deviation were revealed. The results show that the composite particle system is prone to form long cracks. The force chain under the hob cutter is asymmetrically distributed, and the force chain transmission is generated inside the particle system. With the increase of depth, the average stress F in the monodisperse particle system conforms to the polynomial distribution, and the average stress F in the composite particle system increases first and then decreases with the increase of penetration depth. The clustering coefficient and the shortest path of the force-chain network of the composite particle system are sensitive to the penetration process. At the same distance and depth, the J2max of the hard layer particle system is significantly larger than that of the composite particle system.
Study on the influence of axial feed rate on the accuracy of internal gears in power skiving
Authors: Li Jiwu , Zhao Yun 
Published: February 2025

Abstract
In order to improve the machining accuracy of internal gear, the machining accuracy of internal gear was studied using the power skiving technology. In this paper, the geometric model of the power skiving process without considering the manufacturing and installation errors of the cutter is constructed. The generation mechanism of the profile error and the tooth direction error of the internal gear is studied. The influence of the axial feed rate on the gear scraping process is analyzed, and the optimal feeding mode is obtained. The simulation results show that the influence of axial feed rate on the profile error and the tooth direction error is less than 1 μm. With the increase in feed rate, the profile error and the tooth direction error both increase and the profile error is greater than the tooth direction error. Compared with the simulation results, the error of the profile obtained by the actual machining experiment is larger than the theoretical error, and the increased value is within the range of tool error, which verifies the validity of the geometric model in estimating the process of skiving.
Numerical simulation of stud-type four-way erosion under fracturing conditions
Authors: Li Yong , Zhang Zhiqiang , Wang Xiaogang , Hu Yuanhang , Tan Aifang , Zhang Hao , Zhang Jingqiu , Yang Wei 
Published: February 2025

Abstract
The stud-type four-way valve is commonly employed in high-pressure fracturing manifolds, where the inner wall of the valve is subjected to significant erosion and wear due to particle impact and high internal pressure during fracturing operations. This study establishes a theoretical model for erosion wear and utilizes FLUENT simulation software to analyze the variation of erosion wear under different operating conditions for both the Φ130-105 full four-way valve and the Φ130-78 four-way valve. Additionally, it investigates the influence of corner radius at the intersection on the maximum erosion rate, providing theoretical insights for mitigating erosion wear and enhancing the longevity of these valves. Research findings indicate that: (1) For the Φ130-105 full four-way valve under spacing plugging and adjacent plugging working condition, an increase in fluid flow velocity and particle mass flow rate significantly exacerbates erosion wear. Moreover, there is an opposite trend in erosion wear with increasing particle diameter under these two conditions; (2) In working condition “three in and one out” of the Φ130-78 four-way valve, erosion wear increases with higher speed difference between two pipes; while in working condition “two in and one out”, increased fluid flow velocity also notably intensifies erosion wear. Furthermore, an increase in particle diameter leads to reduced maximum erosive damage under both conditions, whereas an increase in mass flow rate results in elevated maximum erosive rates; (3) The introduction of a circular radius at the intersection effectively reduces erosive damage. The optimal circular radius at this intersection is found to be 40 mm for the Φ130-105 full four-way valve and 55 mm for the 0130-78 four-way valve.
Numerical simulation for friction stir welding of dissimilar materials
Authors: Sun Huanhuan , Liu Yilin , Liu Ping , Feng Xinyuan , Wu Dan 
Published: February 2025

Abstract
TiB2/7050 composite is a new kind of lightweight and high-strength engineering material. Friction stir welding is a reliable method for realizing its high-quality connection. In this paper, the friction stir welding processing of TiB2/7050 composite and 7075Al dissimilar materials was simulated. The influence of welding parameters on the flow field and temperature field was studied. The results show that the welding heat input is moderate, and the plastic flow of weld metal is sufficient when the rotating speed of the stirring head is 1200 r/min and the traveling speed is 150 mm/min. The work can provide important references for the reliable connection of TiB2/7050-7075Al dissimilar materials.
Simulation research on the grinding force of a single abrasive particle
Authors: Guan Peng , Feng Zehao , Lin Renliang , Chen Jiaying 
Published: February 2025

Abstract
The grinding process is very complicated, and its mechanism is difficult to explain by traditional research methods because of the irregularity of its surface. The purpose of this paper is to change this process into a single grinding process and to obtain the changing rules of grinding force during grinding. Conclusion: The grinding process is accompanied by the stages of scraping, ploughing, and chip formation. The increase in the front angle of the grain leads to a decrease in grinding force, and the increase in grinding speed leads to a slow increase in grinding force. If the grinding depth increases, the tangential grinding force will increase significantly. The average error obtained by the mathematical model is less than 15%, which meets the requirement of simulation reliability.
Analysis of microstructure and properties of mn-reduced trip steel at different annealing temperatures
Authors: Yuan Bingyu , Xu Yunbo , Hou Xingxia , Gao Yijing 
Published: February 2025

Abstract
The microstructure and properties of Mn-reduced TRIP steel at different IA temperatures were analyzed in this paper. By dilatometer, the Ac1 and Ac3 were measured, which are 740°C and 969°C, respectively. According to the K-M equation, 790°C is the optimal IA temperature with 24.3% RA. The samples annealed for 5 minutes at 770-830°C were characterized and tensile detection was performed. The results reveal that the rising IA temperature gives rise to cementite dissolves and the volume fraction of M/A Island increases gradually. YS and TE decrease first and then increase, YS ranges from 436 MPa to 665 Mpa, and TE ranges from 10.87% to 23.9%. UTS increases monotonically from 878 MPa to 1366 MPa. In conclusion, the sample annealed at 800°C has excellent mechanical properties (UTS=1224 MPa, TE=17.54%). Therefore, 800°C is considered to be the actual optimal IA temperature, containing 25.4% RA. This study provides a theoretical foundation for the subsequent experiment.
Experimental research on the spreading performance of fire extinguishing foam with different expansion
Authors: Chen Yang , Bao Zhiming , Jing Lishuai , Ke Xin 
Published: February 2025

Abstract
In this paper, the spreading properties of foam with different expansions were compared and analyzed, and the reasons were discussed by studying the archaeological properties of foam. The experiment shows that the viscosity and yield stress of foam increase with the increase of expansion ratio, which results in the slow spreading speed of foam on the fuel layer. In addition, the foam with the expansion ratio 6 can quickly form a “water film” due to its accelerated liquid separation process, and the spreading speed on the oil surface is significantly improved. This study provides theoretical support for the optimization and application of foam fire extinguishing technology.
Simulation and experimental study of laser ignition characteristics of potassium boron nitrate
Authors: Li Linpeng , Ba Shuhong 
Published: February 2025

Abstract
To investigate the laser ignition law of B/KNO3, based on the solid-phase reaction, a simulation model of the laser ignition of B/KNO3 was established by using COMSOL software, and the ignition delay time and ignition threshold of B/KNO3 were simulated and calculated under the conditions of different laser powers, spot diameters, and rising edge times. The results show that the ignition delay time of B/KNO3 is shortened with the increase of laser power and increased with the increase of spot diameter. The laser ignition of B/KNO3 was carried out by using a laser with a wavelength of 808 nm and a power density of 194.28 W.cm−2. It was found that the ignition delay time of B/KNO3 was 112 ms and the ignition threshold was 274.75 mJ.