bluuebunny/crossref_metadata_2025 huggingface dataset:
The isotopic composition of the new enriched silicon crystal Si28-31Pr11: maintaining the realization and dissemination of the mole and the kilogram via the XRCD method
Authors: Pramann Axel , Rienitz Olaf
Published: January 2024

The molar mass and isotopic composition of a new silicon single crystal material (Si28-31Pr11) highly enriched in 28Si has been determined in the context of the x-ray crystal density method used for the realization and dissemination of the SI base units‒the mole and the kilogram. Isotope ratio measurements have been performed using a high-resolution multicollector-inductively coupled plasma mass spectrometer (MC-ICP-MS) with improved technical performance. By applying the Virtual-Element Isotope Dilution Mass Spectrometry method, different crystal areas enclosing the locations of two silicon spheres have been investigated with respect to the magnitude of tentative variations in the molar mass and isotopic composition of the respective samples as a function of their original location in the crystal ingot. In total, 18 subsamples from four different axial and several related radial positions have been characterized. An average molar mass M(Si28-31Pr11) = 27.976 941 464(41) g mol−1 corresponding to a relative combined uncertainty u
c,rel(M(Si28-31Pr11)) = 1.4 × 10−9 was yielded. The average enrichment in 28Si of the crystal is expressed by the mean amount-of-substance fraction x(28Si) = 0.999 985 350(37). Two spheres were cut from the crystal ingot. The average molar masses of the spheres Si28kg_03_a and Si28kg_03_b are: M(Si28kg_03_a) = 27.976 941 467(43) g mol−1 and M(Si28kg_03_b) = 27.976 941 461(44) g mol−1, respectively. The results are discussed using uncertainty budgets according to the Guide to the expression of uncertainty in measurement. A homogeneous distribution of the molar mass throughout the crystal is suggested, qualifying it as a material for a primary standard–a silicon sphere–for the realization and dissemination of the mole and the kilogram. A comparison with enriched silicon crystals that are already available is given.
A novel prediction model of the freckle defects for single-crystal superalloy blades
Authors: Liu Y , Wang F
Published: January 2024

The freckle is a typical surface defect formed during the directional solidification of SC (single crystal) components of Ni-based superalloys. It generally appears as a long and narrow trail of equiaxed grains aligned roughly parallel to the direction of gravity, which breaks the integrity. Once appears, the freckle can never be avoided by further treatment. With the turbine blade requirements increasing, the state-of-the-art methods include adding more refractory elements into Ni-based SC superalloys, and the design of blades with a more complex geometric shape make the freckle defects grow easier at the special surface zones. This leads to a significant challenge in controlling grain defect formation in SC blades and vanes for freckles. The current consensus to freckle formation is described as the Rayleigh-Taylor instability (RTI) flow that occurred in the interdendritic zone. During solidification, the compositional segregation (CS) occurred as soon as the solid interface forwarding led to the density changes between the interdendritic melting phases and the residual liquids. For nickel-based superalloys, the enrichment of low-density solutes like Al, and Ti at the interdendritic zone will make the liquid lighter. However, the widely used Ra model can’t correctly match the freckle tendency of the components with complex shapes (called geometrical effects of freckles), especially for blades. Recent reports indicate that the freckles occur at the preferred positions in the casting. In this work, a novel model is designed to quantitatively discuss the geometrical effects on freckle formation and to combine existing Ra number models with solidification models to enable freckle predictions at a smaller scale. The proceeding of this work can make the design of complex blades easier.
Study on high cycle fatigue performance at elevated temperature for a selective laser melted Ti6Al4V alloy
Authors: Jiao Z H , Xu R D , Yu H C , Wu L L , Wu X R
Published: January 2024

Selective laser melted Ti6Al4V alloy has broad application prospects in aeroengine field. In this study, high cycle fatigue tests were carried out systematically using hourglass shaped specimen (K
t=1) at 400 °C. The S-N curves were acquired and compared with data of the casting and the forging. The anisotropy and the defect effects of the fatigue performance were analysed. The LOF defects on the surface and subsurface preferentially act as the fatigue crack initiation site for almost all the tested HCF specimens. The position and irregularity of defect have greater influence on elevated temperature fatigue life than the defect size. The fatigue strength of horizontal orientation is lower than that of vertical orientation, because of the characteristics of larger size, more irregular shape and higher density for the crack source defects of horizontal specimens. The fatigue performance of the SLM Ti6Al4V alloy in this study is better than that of the casting and even the forging, but the dispersion of fatigue data of the SLM alloy is much greater than that of the both traditional process alloys.
Study on Smart Street Light (SSL) using Ultra Narrowband (UNB) Technology: a case study of Malaysia Power Utility
Authors: Ruszaini N D , Abdullah K , Busrah A M
Published: January 2024

Street light is important to road user and residential area to improve visibility and creating safer road by preventing traffic accidents and also by reducing crime. However, present practice for street lighting management largely remains a challenge. Smart Street Lighting (SSL) system is a system where the street lighting system adds up with communication technology producing a real time monitoring system. Smart Street Lighting (SSL) is known to gain high value creation through maintenance savings and improvement of the environmental impact for Malaysia. Tenaga Nasional Berhad (TNB) through its research arm, TNB Research (TNBR) has recently carried a feasibility study on the compatibility of SSL system using Ultra Narrowband (UNB) technology on the energy efficient and better light intensity of light-emitting diode (LED) lighting technology street light. The SSL systems have been deployed on a small scale, tested and monitored at selected areas. This paper discussed the technical performance such as functionality and compatibility that have been assessed in the study.
Experimental investigations on the collapse of spiral-stiffened cylindrical shells under external hydrostatic pressure
Authors: Wang Xiaoyong , Zhuang Hong , Xu Shuhui , Tang Wenxian , Zhang Jian , Zhan Ming
Published: January 2024

This paper presents a comprehensive experimental investigation into the collapse behavior of spiral stiffened cylindrical shells under external hydrostatic pressure. Spiral stiffened cylindrical shells with two different pitches and cylindrical shells were designed and fabricated. The fabricated specimens were divided into three groups. Each group has two identical specimens. Test specimens were welded from stainless steel. The shell was formed by cold bending, and the spiral ribs were welded to the surface of the shell to form a spiral stiffened cylindrical shell. Measurements of initial geometric imperfections and shell thickness were performed on the fabricated specimens to verify the accuracy of fabricating. Subsequently, the specimens were placed in a pressure chamber and pressurized until collapsed to obtain the ultimate collapse pressure and collapse modes. In addition, a uniaxial tensile test was conducted on the shell material to obtain its material properties. Experimental results indicated that the fabricated specimens had excellent repeatability and reasonable precision. The presence of a spiral rib effectively boosted the ultimate collapse pressure of the cylindrical shell with a more pronounced strengthening effect observed as the rib density increased.
Bending and torsional coupling study of rolling-piston compressor valves
Authors: Gao Wenzhao , Zhang Chaolei , Chen Debiao
Published: January 2024

In this paper, a model of a rolling compressor valve with one end fixed horizontally is presented and simulated using the flow-solid coupling (FSI) method for rolling rotor type compressors. Optimisation of the diagonally cut section can effectively reduce the pressure pulsation of the compressor. The results show that the valve blade generates coupled vibrations of bending and torsion, and the slant-cut structure improves the frequency of pressure pulsations, increases the stability of the compressor valve blade, optimises the compressor structure and reduces the pressure pulsations of the compressor.
Design and strength simulation of hub mechanism of variable pitch propeller
Authors: Ning Huizi , Zhong Bowen , Sun Lubin , Yu Zhiming , Zeng Chujing
Published: January 2024

The hub mechanism is an important force bearing mechanism of variable pitch propellers and an important actuator of variable pitch control in tilting ducted propeller UAV. To solve the problem of the connection between the blades and the fuselage of the tilting ducted propeller UAV, according to the parameters of the blades, the force of the hub mechanism is analyzed, and the design parameters of the hub mechanism are obtained by using the theoretical calculation method, such as the power density method. The strength of the parts is analyzed by using the finite element method. A variable-pitch propeller hub mechanism was developed for tilting ducted unmanned aerial vehicles. A design flow of the hub mechanism is formed, including the design of the parts of the hub mechanism and the strength check. This will facilitate the design and development of ducted UAVs.
Virtual maintenance simulation technology in civil aircraft engineering
Authors: Xia Jian
Published: January 2024

Based on the requirements and characteristics of civil aircraft maintainability design, virtual simulation technology is introduced into aircraft maintainability design, analysis, and verification. This paper presents the flow of virtual maintenance simulation through visual analysis, physical accessibility analysis, and operational space analysis. A method of virtual maintenance simulation accessibility analysis is presented. The evaluation of virtual simulation design is realized. In the design stage, through the virtual maintenance simulation analysis, the design factors affecting maintenance and potential maintenance hazards are found in advance. A timely improvement is made to improve the level of aircraft maintainability design and reduce later maintenance costs.
Design and numerical simulation analysis of a miniature Mixed-flow compressor
Authors: Li Zilin , Song Danlu , Wang Linsheng
Published: January 2024

This paper completed the pneumatic design of a mixed-flow compressor, adopted RANS turbulence model, and chose Spalart-Allmaras model to complete the numerical simulation of the flow field of the S1 flow surface, meridian flow surface, and impeller surface, and then analyzed the working performance at 90%, 100%, and 110% design speed to explore whether the mixed-flow compressor technology suitable for micro turbojet engines as well as the internal flow field flow state and loss mechanism. The results indicate that the shock wave at the front edge of the main blade and the low energy gas gathered at the tail edge of the main blade and the shunt blade, which causes serious flow blockage, are the main causes of the instability of the mixed-flow compressor at the design point. At 100% design speed, the compressor has higher reliability, stronger adaptability, and the best working performance for its working margin, isentropic efficiency, and pressure ratio with lower loss. The results may provide some references for the further optimization design of the current compressor.
Manufacturing process and raw materials of bearing windshield
Authors: Ma Yinglong
Published: January 2024

The windshield is an important part of the aircraft structure. In addition to providing a clear driving vision for the driver, it also needs to have certain strength and stiffness performance to meet the pressurization static load and impact dynamic load. At the same time, the windshield glass also needs to have a certain function of heating, anti-icing, and defogging. According to the application scenarios, the windshield can be divided into two types: bearing windshield and non-bearing windshield. Due to the requirement of weight, appearance, and security of the bearing windshield, it will become the mainstream design trend in the future. However, bearing windshield is composed of a wide variety of raw materials with different performances, the manufacturing process is complex, and the research and development verification tests are difficult. This paper introduces and summarizes the main difficulties and index requirements of the bearing windshield in terms of structural design, manufacturing process, and raw materials, and provides guidance and support for the subsequent airworthiness compliance verification of the bearing windshield.
Increasing gross primary productivity under soil warming and wetting on the Tibetan Plateau
Authors: Peng Qing , Jia Binghao , Lai Xin , Wang Longhuan , Huang Qifeng
Published: January 2024

The soil freeze-thaw process has undergone significant changes on the Tibetan Plateau (TP) in the context of global change, resulting in the changes of soil physical and chemical properties, thereby affecting the vegetation phenology and photosynthesis through affecting the utilization capacity of CO2 and light by vegetation. However, little is known about how soil temperature (ST) and soil moisture (SM) affect the gross primary productivity (GPP) on the TP at different seasons and elevations. In this study, the spatiotemporal variation patterns of GPP, ST, and SM were analyzed based on the Community Land Model version 5.0 (CLM5.0) simulations in order to illustrate the impacts of ST and SM in surface (0–10 cm) and root zone soil (0–100 cm) on GPP between 1979 and 2020. The results showed that the CLM5.0-based GPP and ST were in good agreement with in situ observations. ST, SM and GPP increased at the rates of 0.04 °C a−1, 2.4 × 10−4mm3 mm−3 a−1, and 5.36 g C m−2 a−2, respectively. SM dominated the variations of GPP in winter (64.3%), while ST almost was the dominant factor in other periods, especially spring (99.9%) and autumn (94.7%). The explanatory power of ST and SM for GPP increased with elevation, especially for ST. The relative contributions of ST and SM to GPP at different time scales in root zone soil were similar to those in surface soil. This study provided a new understanding of how soil freeze-thaw affected GPP changes on the TP in the context of the intensification of warming and humidification.
Quantum holographic surface anomalies
Authors: Drukker Nadav , Shahpo Omar , Trépanier Maxime
Published: January 2024

Expectation values of surface operators suffer from logarithmic divergences reflecting a conformal anomaly. In a holographic setting, where surface operators can be computed by a minimal surface in AdS, the leading contribution to the anomaly comes from a divergence in the classical action (or area) of the minimal surface. We study the subleading correction to it due to quantum fluctuations of the minimal surface. In the same way that the divergence in the area does not require a global solution but only a near-boundary analysis, the same holds for the quantum corrections. We study the asymptotic form of the fluctuation determinant and show how to use the heat kernel to calculate the quantum anomaly. In the case of M2-branes describing surface operators in the

N

=
(
2
,
0
)

theory in 6d, our calculation of the one-loop determinant reproduces expressions for the anomaly that have been found by less direct methods.
Estimation of cohesion for intact rock materials using regression and soft computing analyses
Authors: Köken E , Strzałkowski P , Kaźmierczak U
Published: January 2024

Abstract Shear strength parameters such as cohesion (c) and internal friction angle (ϕ) are among the most critical rock properties used in the geotechnical design of most engineering projects. However, the determination of these properties is laboring and requires special equipment. Therefore, this study introduces several predictive models based on regression and artificial intelligence methods to estimate the c of different rock types. For this purpose, a comprehensive literature survey is carried out to collect quantitative data on the shear strength properties of different rock types. Then, regression and soft computing analyses are performed to establish several predictive models based on the collected data. As a result of these analyses, five different predictive models (M1–M5) were established. Based on the performance of the established predictive models, the artificial neural network-based predictive model (model 5, M5) was the most suitable choice for evaluating the c for different rock types. In addition, mathematical expressions behind the M5 model are also presented in this study to allow users to implement it more efficiently. In this regard, the present study can be declared a case study showing the applicability of regression and soft computing analyses to evaluate the c of different rock types. However, the number of datasets used in this study should be increased to get more comprehensive predictive models in future studies.
Data-driven revision of coal spontaneous combustion risk classification for prevailing methods used in Australian mining industry
Authors: Zeng S , D’Hyon S , Widzyk-Capehart E
Published: January 2024

Spontaneous combustion poses persistent hazards in underground coal mining operations, threatening personnel and operations. To assess this risk, in Australia small-scale laboratory tests are being conducted using Adiabatic Oxidation (R70), Crossing Point (CPT) and Minimum Self-Heating Temperature (SHTmin) methods. The intrinsic spontaneous combustion propensity classification (ISCP) utilizes R70 results to establish a risk rating. This risk ranking provides guidance on the severity of spontaneous combustion ranging from low to extremely high, aiding in the implementation of preventive measures. However, The ISCP lacks supporting literature, and there is no existing literature on correlation between laboratory tests or risk matrix for CPT. This paper presents the results of a Spearman correlation study among R70, CPT and SHTmin based on a large historical database (n = 318) showing that only R70 and CPT can be used to reliably rank spontaneous combustion risk. It was found that CPT is strongly correlated with R70 (ρ = -0.8875), but SHTmin shows a weaker correlation with R70 (ρ = -0.7265). The hierarchical clustering analysis resulted in a revised risk ranking: Low (R70 < 0.4 °C/h, CPT > 156 °C), Medium (0.4 °C/h < R70 < 3 °C/h, 132 °C < CPT < 156 °C), High (3 °C/h < R70 < 11 °C/h, 102 °C < CPT < 132 °C), and Very High (R70 > 11 °C/h, CPT < 102 °C).
Identification of the oversized rock pieces in hydraulic hammer breaking process based on the scanner data geometry features analysis
Authors: Dąbek Przemysław , Kujawa Paulina , Wróblewski Adam
Published: January 2024

Due to the harsh conditions in the mining environment, it is difficult to fully automate some of the tasks carried out by mining machines and devices. As part of the technological process of extracting copper ore from Polish mines, the material is broken with a hammer to fit through the screen of a 40×40 cm square shape slot, after which it is loaded and conveyed for further processing. Usually, most of the material remaining on the screen cannot be considered oversized, additionally smaller particles can form blockages or rest on larger blocks. In this case, the crushing is not necessary, and only its movement may be sufficient. The focus of the presented research is on the identification of the particles that would be considered oversized, as it is a crucial task in the breaking hammer automation process. The authors propose a method based on the analysis of initially extracted 3D data copper ore blocks obtained from laser scanning at one of the transfer stations in KGHM Polska Miedź S.A., Polkowice-Sieroszowice mine. The difficulties of measurement are multiplied by the necessity of performing the scan from a single point of view, which was forced by safety concerns. Segmented but incomplete 3D data are processed, which results in finding the geometric features that prevent the material from going through the screen in an automatic manner.
Comparison of Hexcore and Poly-Hexcore computational meshes in the aspect of air flow modeling based on the actual geometry of mining excavations
Authors: Wróblewski Adam , Macek Arkadiusz , Bansiewicz Aleksandra , Wodecki Jacek
Published: January 2024

Discrete models are used in industry for many applications. In one of the most frequently used Finite Element Method (FEM) for Computational Fluid Dynamics (CFD) calculations, discrete models may be two-dimensional or three-dimensional. 2D models are used as a simplification to achieve satisfied results in the shortest computational time. 3D models, on the other hand, are used for more complex calculations. These models constitute a representation of real-world objects that have been appropriately simplified to make the calculations accurate and correct. The calculation time of a 3D model is significantly longer compared to a 2D model. For this reason, to reduce the calculation time, different types of simplifications and various types of discrete model meshes are used. In this paper, the authors made a comparison of two computational meshing technologies: Hexcore and Poly-Hexcore in the aspect of airflow modeling in mining excavations using CFD. The geometry considered in this case came from real-world excavations captured by laser scanning in the Gertruda Slant, Zloty Stok. Point cloud data was processed through feature extraction, which was subsequently utilized to create structured models of mining excavations. The results of the simulations show that taking into account such a diverse and complicated geometry and its significant lengths, reaching tens of kilometers, better results are obtained with the use of Poly-Hexcore mesh. This type of mesh allows simulations to be performed with similar accuracy in a shorter computation time. Utilizing a more modern type of mesh makes work more dynamic, which is of particular importance when conducting numerical simulations of air distribution in large and complex computational domains.
The influence of the void shape in the bearing capacity of rock mass with a superficial void
Authors: Alencar A , Galindo R , Dominguez-Quintans C
Published: January 2024

In this study is proposed a chart that allow estimating the reduction of bearing capacity due to the existence of a superficial void in a rock mass. It is contemplated the influence of different shapes and size of the void in relation to the foundation. The reduction of the bearing capacity is analyzed through the Finite Difference Method. In the numerical model, six possible cavity shapes are considered, with three different sizes and depths. Calculations are made considering eighteen types of rock masses, modelled by the H&B failure criterion. The results demonstrate that the critical depth where the cavity no longer influences the bearing capacity varies considerably depending on the geometric variables (size, shape and location of the void). In addition, it is observed that the relation between the bearing capacity obtained considering the rock mass with and without void is not affected by the geotechnical parameters of the H&B failure criterion. According to the results analyzed and graphic output, the variation in the stress distribution in the rock mass and the change of the failure mechanism under the different hypotheses studied can be observed. The results are presented in chart that facilitate to directly estimate the reduction of the bearing capacity of a rock mass with void based on geometric parameters.
Perturbative variational quantum algorithms for material simulations
Authors: Liu Jie , Li Zhenyu , Yang Jinlong
Published: January 2024

Reducing circuit depth is essential for implementing quantum simulations of electronic structure on near-term quantum devices. In this work, we propose a variational quantum eigensolver (VQE) based perturbation theory (PT) algorithm to accurately simulate electron correlation of periodic materials with shallow ansatz circuits, which are generated from adaptive derivative-assembled pseudo-trotter or qubit-excitation-based VQE calculations using a loose convergence criteria. Here, the major part of the electron correlation is described using the VQE ansatz circuit and the remaining correlation energy is described by either multireference or similarity transformation-based PT. Numerical results demonstrate that the new algorithms are able to accurately describe electron correlation of the LiH crystal with only one circuit parameter, in contrast with ~30 parameters required in the adaptive VQE to achieve the same accuracy. Meanwhile, for fixed-depth ansätze, e.g. unitary coupled cluster, we demonstrate that the VQE-based PT provides an appealing scheme to improve their accuracy.
Intercalation in Li-ion batteries: thermodynamics and its relation to non-ideal solid-state diffusion
Authors: Lagnoni Marco , Armiento Gaia , Nicolella Cristiano , Bertei Antonio
Published: January 2024

Intercalation is the key phenomenon taking place in lithium-ion batteries: while its thermodynamics sets the equilibrium voltage of active materials, solid-state diffusion of intercalated lithium determines the rate at which the battery can operate. This study revisits the thermodynamics of intercalation by treating the active material as a binary mixture of filled and empty sites, thus relating the equilibrium potential to the chemical potential difference of intercalated lithium. By setting a reference to unitary activity at half state-of-lithiation, the non-ideal behaviour of the active material is quantified via a revisited form of the thermodynamic enhancement factor, revealing that common solid-solution cathode materials as LiNi
x
Mn
y
Co1-x-y
O2, LiNi0.8Co0.15Al0.05O2, and LiCoO2 show strong super-ideal behaviour. The latter is related to the thermodynamic enhancement of the diffusion coefficient of intercalated lithium. A comprehensive overview of the functional forms of Li diffusion flux according to linear irreversible thermodynamics is provided and related to the chemical diffusion coefficient obtained by conventional characterisation techniques. A literature analysis made on solid-solution cathode active materials reveals that while the chemical diffusion coefficient varies significantly with state-of-lithiation, there exists a convenient functional form of diffusion flux according to linear irreversible thermodynamics that enables a fairly stable diffusion coefficient with state-of-lithiation. This has clear benefits from both modelling and experimental viewpoints and potentially sheds light on the mechanistic fundamentals of solid-state diffusion.
Treatment of acidic electroplating effluent from small scale industries using batch and continuous flow adsorption reactor
Authors: Anand A Mahesh , Jegathambal P , Jannet Sabitha , Mayilswami C
Published: January 2024

If electroplating effluent discharges aren’t properly treated, they have a detrimental effect on the aquatic ecology. The effluent characteristics comprise heavy metals that were toxic and causes carcinogenic effects. Among the conventional methods, adsorption being the most economically viable and technically straightforward. This study focuses on the removal of hexavalent chromium ion from the electroplating effluent using commercial activated carbon in both batch and continuous flow experiments. In column studies, various grades of commercial activated carbon were tested, with 80 × 200 mesh size yields complete Cr6+ removal. The batch study revealed that 83% removal was achieved at 5g of 80 × 200 mesh size activated carbon. The isotherm studies indicated a better fit with the Langmuir model and kinetics studies indicated pseudo-second order kinetics. Continuous flow experiments with an 80 × 200 mesh size activated carbon bed showed an upward trend in pH. However, Cr6+ removal efficiency decreased over time. UV–vis spectroscopy using the Diphenyl carbazide method confirmed Cr6+ concentrations. Morphological and elemental analyses were conducted using SEM and Edax, revealing significant changes before and after treatment. These findings underscore the effectiveness of activated carbon in mitigating the environmental impact of electroplating effluents, particularly in Cr6+ removal.
A boiler oxygen content and furnace temperature prediction model based on honey badger algorithm optimized neural network
Authors: Ji Zhaoyu , Tao Wenhua , Zhang Lingxiang
Published: January 2024

Aiming at the problem that it is difficult to accurately predict the oxygen content and furnace temperature during the combustion process inside the circulating fluidized bed boiler, this paper proposes a prediction model with a mixture of the convolutional neural network(CNN), bi-directional long-short term memory network(biLSTM), and honey badger algorithm(HBA). First, process variables related to furnace temperature and oxygen content were selected as input variables using actual test data from circulating fluidized bed boilers. Secondly, the parsed input variables are analyzed by CNN through an analytical mechanism to extract the data into smaller details and features, which are used as inputs to the biLSTM layer. The BiLSTM layer selectively memorizes the information of the input temporal data and learns the information dependence of the temporal data sequences, which then solves the temporal problem of the training of the irregular trend of the oxygen content and the furnace temperature. Finally, the HBA is utilized to continuously traverse and search the CNN-biLSTM model to find the optimal parameters of the model. The experimental results show: the CNN-biLSTM neural network model mixed with the HBA is able to accurately predict the oxygen content and furnace temperature. The experimental results show that the CNN-biLSTM neural network model with hybrid HBA is able to accurately predict the oxygen content and furnace temperature, and the average MAPE errors for the oxygen content are HBA-CNN-biLSTM (2.92E-03), CNN (7.96E-02), LSTM (5.13E-02), GRU (4.83E-02), RF (4.96E-02), RBF (8.41E-02), SVM (5.71E-02), RNN (5.53E-02), CNN-LSTM (4.79E-02).
Structural and antibacterial properties of copper oxide nanoparticles: a study on the effect of calcination temperature
Authors: Motshekga Sarah Constance
Published: January 2024

Nanoparticles of copper oxide were synthesized by the simple precipitation method. The influence of calcination temperature on the structural characteristics and antibacterial activity of the nanoparticles were evaluated. The nanoparticles were analyzed by Bruner-Emmett-Teller (BET) surface area and pore size analyzer, x-ray diffraction, transmission electron microscope and scanning electron microscope. The findings demonstrated the formation of copper oxide nanoparticles showing a monoclinic phase. Before calcination, the nanoparticles showed a high BET surface area with rod shape morphology and size range between 18–70 nm and after calcination, irregular spherical-like morphology with size range of 20–200 nm was observed. However, it was evident that the BET surface area decreased gradually with increasing calcination temperature, while the nanoparticle size increased forming an irregular spherical shape. Subsequently, the copper oxide nanoparticles demonstrated that they are highly effective for bacteria inactivation. The inactivation activity was found to be more effective with uncalcined nanoparticles than with calcined nanoparticles. This was due to the large nanoparticle sizes and the decrease in surface area obtained after calcination. Thus, it was noted that calcination of the as-prepared nanoparticles significantly affects the structural and antibacterial properties. Hence, for antibacterial application, calcination was not necessary as the nanoparticles showed excellent antibacterial results.
On boundedness of singularities and minimal log discrepancies of Kollár components
Authors: Zhuang Ziquan
Published: January 2024

Recent study in K-stability suggests that Kawamata log terminal (klt) singularities whose local volumes are bounded away from zero should be bounded up to special degeneration. We show that this is true in dimension three, or when the minimal log discrepancies of Kollár components are bounded from above. We conjecture that the minimal log discrepancies of Kollár components are always bounded from above, and verify it in dimension three when the local volumes are bounded away from zero. We also answer a question from Han, Liu, and Qi on the relation between log canonical thresholds and local volumes.
Chern-Weil theory for ∞-local systems
Authors: Arias Abad Camilo , Pineda Montoya Santiago , Quintero Vélez Alexander
Published: January 2024

Let

G
G

be a compact connected Lie group with Lie algebra

g

\mathfrak {g}

. We show that the category

L
o
c

∞

⁡
(
B
G
)

\operatorname {\mathbf {Loc}} _\infty (BG)

of

∞
\infty

-local systems on the classifying space of

G
G

can be described infinitesimally as the category

I
n
f

L
o
c

∞

(

g

)

{\operatorname {\mathbf {Inf}\mathbf {Loc}}} _{\infty }(\mathfrak {g})

of basic

g

\mathfrak {g}

-

L
∞

L_\infty

spaces. Moreover, we show that, given a principal bundle

π
:
P
→
X

\pi \colon P \to X

with structure group

G
G

and any connection

θ
\theta

on

P
P

, there is a differntial graded (DG) functor
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="script upper C script upper W Subscript theta Baseline colon bold upper I bold n bold f bold upper L bold o bold c Subscript normal infinity Baseline left-parenthesis German g right-parenthesis long right-arrow bold upper L bold o bold c Subscript normal infinity Baseline left-parenthesis upper X right-parenthesis comma">

C
W

θ

:

I
n
f

L
o
c

∞

(

g

)
⟶

L
o
c

∞

(
X
)
,

\begin{equation*} \mathscr {CW}_{\theta } \colon \mathbf {Inf}\mathbf {Loc}_{\infty }(\mathfrak {g}) \longrightarrow \mathbf {Loc}_{\infty }(X), \end{equation*}

which corresponds to the pullback functor by the classifying map of

P
P

. The DG functors associated to different connections are related by an

A
∞

A_\infty

-natural isomorphism. This construction provides a categorification of the Chern-Weil homomorphism, which is recovered by applying the functor

C
W

θ

\mathscr {CW}_{\theta }

to the endomorphisms of the constant

∞
\infty

-local system.
Sums of random polynomials with differing degrees
Authors: Kraus Isabelle , Michelen Marcus , O’Rourke Sean
Published: January 2024

Let

μ
\mu

and

ν
\nu

be probability measures in the complex plane, and let

p
p

and

q
q

be independent random polynomials of degree

n
n

, whose roots are chosen independently from

μ
\mu

and

ν
\nu

, respectively. Under assumptions on the measures

μ
\mu

and

ν
\nu

, the limiting distribution for the zeros of the sum

p
+
q

p+q

was computed by Reddy and the third author [J. Math. Anal. Appl. 495 (2021), p. 124719] as

n
→
∞

n \to \infty

. In this paper, we generalize and extend this result to the case where

p
p

and

q
q

have different degrees. In this case, the logarithmic potential of the limiting distribution is given by the pointwise maximum of the logarithmic potentials of

μ
\mu

and

ν
\nu

, scaled by the limiting ratio of the degrees of

p
p

and

q
q

. Additionally, our approach provides a complete description of the limiting distribution for the zeros of

p
+
q

p + q

for any pair of measures

μ
\mu

and

ν
\nu

, with different limiting behavior shown in the case when at least one of the measures fails to have a logarithmic moment.
What Should Go With This Word Here: Connecting Lexical Collocations and Rhetorical Moves in Narrative Stories
Authors: Jiang Yishi , Lu Xiaofei , Liu Fengkai , Zhang Jianxin , Jin Tan
Published: January 2024

An emerging body of corpus-based genre analysis studies has examined the connection between different types of formulaic language and rhetorical moves in various genres of academic writing. The current study extends this body of research into the understudied genre of narrative stories and the understudied phraseological unit of lexical collocations. Specifically, we compiled a corpus of narrative stories written by expert writers, extracted a list of frequent collocations from the corpus, developed a rhetorical move framework for narrative stories, examined the distribution of rhetorical stages and moves in the corpus, and explored the connection between collocations and rhetorical moves in the corpus. The findings of our research culminated in an online interface for searching the corpus for collocations and exploring their use in sentences realizing different rhetorical stages and moves in context. We discuss the potential pedagogical value of our findings and the resulting online interface for promoting learner awareness of the connection between linguistic features and rhetorical functions in narrative stories in genre-based pedagogy.
A simple refined DNA minimizer operator enables 2-fold faster computation
Authors: Pan Chenxu , Reinert Knut
Published: January 2024

Motivation

The minimizer concept is a data structure for sequence sketching. The standard canonical minimizer selects a subset of k-mers from the given DNA sequence by comparing the forward and reverse k-mers in a window simultaneously according to a predefined selection scheme. It is widely employed by sequence analysis such as read mapping and assembly. k-mer density, k-mer repetitiveness (e.g. k-mer bias), and computational efficiency are three critical measurements for minimizer selection schemes. However, there exist trade-offs between kinds of minimizer variants. Generic, effective, and efficient are always the requirements for high-performance minimizer algorithms.

Results

We propose a simple minimizer operator as a refinement of the standard canonical minimizer. It takes only a few operations to compute. However, it can improve the k-mer repetitiveness, especially for the lexicographic order. It applies to other selection schemes of total orders (e.g. random orders). Moreover, it is computationally efficient and the density is close to that of the standard minimizer. The refined minimizer may benefit high-performance applications like binning and read mapping.

Availability and implementation

The source code of the benchmark in this work is available at the github repository https://github.com/xp3i4/mini_benchmark
Activation of interleukin 33-NFκB axis in granulosa cells during atresia and its role in disposal of atretic follicles
Authors: Wu Jean , Carlock Colin , Tatum Kiana , Shim Junbo , Zhou Cindy , Lou Yahuan
Published: January 2024

It has been previously shown that the cytokine interleukin 33 is required for two processes, i.e., autophagic digestion of granulosa cells and recruitment of macrophages into atretic follicles, for full disposal of atretic follicles. Now, this study shows that activation of interleukin 33-suppression of tumorigenicity 2–Nuclear Factor ĸB (NFκB) axis in granulosa in early atretic follicles may regulate those two events. Injection of human chorionic gonadotropin has been shown to induce a transient peak of interleukin 33 expression with synchronized atresia. In this model, interleukin 33-independent expression of suppression of tumorigenicity 2 in granulosa cells was detected in early atretic follicles before macrophage invasion. The activation of NFκB pathway in ovaries was further demonstrated in vivo in Tg mice with luciferase-reporter for NFκB activation; the activation was microscopically localized to granulosa cells in early atretic follicles. Importantly, antibody blockage of interleukin 33 or interleukin 33 Knock-out (KO) (Il33−/−) not only inhibited NFκB activity in ovaries, but it also altered expression of two key genes, i.e., reduction in proinflammatory interleukin6 (IL6) expression, and a surge of potential autophagy-inhibitory mammalian target of rapamycin (mTOR) expression in atretic follicles. By contrast, apoptosis and other genes, such as interleukin1β (IL1β) were not affected. In conclusion, in parallel to apoptosis, atresia signals also trigger activation of the interleukin 33-suppression of tumorigenicity 2–NFκB pathway in granulosa, which leads to (1) down-regulated expression of mTOR that is a negative regulator of autophagy and (2) up-regulated expression of proinflammatory IL6.
Lymph node examination and survival in resected pancreatic ductal adenocarcinoma: retrospective study
Authors: Goess Ruediger , Jäger Carsten , Perinel Julie , Pergolini Ilaria , Demir Elke , Safak Okan , Scheufele Florian , Schorn Stephan , Muckenhuber Alexander , Adham Mustapha , Novotny Alexander , Ceyhan Güralp O , Friess Helmut , Demir Ihsan Ekin
Published: January 2024

Background

The minimum number of examined lymph nodes (ELN) required for adequate staging and best prediction of survival has not been established in pancreatic ductal adenocarcinoma (PDAC). The aim of the study was to investigate the influence of ELN on staging and survival in PDAC.

Methods

Patients undergoing partial or total pancreatectomy for PDAC at two European university hospitals between 2007 and 2018 were retrospectively reviewed. Multivariate Cox regression model and survival analyses were performed to verify adequate staging.

Results

Overall 341 (73 per cent) patients showed lymph node metastasis (N1/N2), whereas 125 (27 per cent) patients had no lymph node involvement (N0). With increasing number of ELN, the proportion of positive lymph nodes increased. The minimum number of ELN needed to detect lymph node involvement was 21. In multivariate analysis, examination of <21 lymph nodes was a significant negative predictor for survival. Examination of ≥21 ELN reversed this effect and ruled out possible misclassification.

Conclusion

The number of ELN affects survival in PDAC. Possible misclassification was identified when <21 lymph nodes were examined. Therefore, at least 21 lymph nodes must be examined to avoid false lymph node classification in all types of resection.
Treatment of moderate-to-severe alopecia areata in patients over the age of 65 years with baricitinib
Authors: Tang Gia Toan , Triwongwaranat Daranporn , Sinclair Rodney , Joseph Shobha , Eisman Samantha , Rathnayake Deepani , Varathan Vanathy , Trindade de Carvalho Lara , Bhoyrul Bevin
Published: January 2024

Baricitinib is a Janus kinase inhibitor that has been approved by the US Food and Drugs Administration for the treatment of severe alopecia areata (AA) in adults. However, the clinical trials that demonstrated the efficacy of baricitinib in the treatment of severe AA did not include men aged > 60 years or women aged > 70 years. We retrospectively assessed the efficacy and safety of baricitinib in 14 patients aged ≥ 65 years with moderate-to-severe AA. After a mean (SD) duration of 18.5 (11.9) months, a 72% reduction in mean Severity of Alopecia Tool score from baseline was observed. Partial or complete eyebrow and eyelash hair was observed in 57% and 43% of patients, respectively. The adverse effects of baricitinib were mild. No cases of venous thromboembolism, major adverse cardiovascular events or malignancy were reported.
Comment on ‘Wound healing, scarring and management’
Authors: Afzal Usamah M , Ali Faisal R
Published: January 2024

We encourage dermatologists to ask patients specifically about restrictive diets (e.g. veganism) and vaping, among other lifestyle factors, when counselling them on expected outcomes after skin surgery.
The future of work and working time: introduction to special issue
Authors: Burchell Brendan , Deakin Simon , Rubery Jill , Spencer David A
Published: January 2024

This introduction to the special issue on the future of work and working time offers an overview of issues of relevance to present-day debates on working time. The aim is to bring together two divergent debates, the first on working time reduction for full-time workers and the second on the diversification and fragmentation of working time. It considers the history of working time including the forces that led to the establishment of the standard employment relationship and to reductions in standard working hours. It addresses contemporary trends and examines why there has been both a stalling of working time reduction and a diversification of working time norms. Some limitations of focussing only on clock time are considered as well as some of the benefits, from more meaningful work to better health and well-being, that stem from both regular and non-excessive working time. The final section turns to the case for reform: it argues that policies are required to address the fragmentation of working time, and that these policies should be combined with a focus on shortening standard working hours that could increase the sustainability of working time in a dual-earner society and even limit the supply of labour for jobs offering only fragmented working time.
The risk of CKD progression remains high in patients treated with ACE inhibitors and ARBs, MRAs and SGLT2 inhibitors. Have we already achieved the therapeutic ceiling in CKD? (The CON part)
Authors: Trillini Matias , Ruggenenti Piero
Published: January 2024

Renin-Angiotensin-System (RAS) inhibitors remained the only effective nephro-protective treatments until recent landmark trials showed that sodium-glucose co-transporter 2 (SGLT2) inhibitors and non-steroid mineral receptor antagonists added-on RAS inhibitor therapy dramatically slowed renal disease progression in patients with chronic kidney disease (CKD). However, despite this impressive advancement, a substantial proportion of patients remains at high risk of renal and cardiovascular events. Thus, we are still far from achieving the therapeutic ceiling in CKD. However, we are entering a new era in the management of patients with CKD with innovative methodological approaches to test disease-modifying medications in the context of personalized medicine.