bluuebunny/crossref_metadata_2025 huggingface dataset:
Consensus from the Brazilian Academy of Neurology for the diagnosis, genetic counseling, and use of disease-modifying therapies in 5q spinal muscular atrophy
Authors: Zanoteli Edmar , Araujo Alexandra Prufer de Queiróz Campos , Becker Michele Michelin , Fortes Clarisse Pereira Dias Drumond , França Marcondes Cavalcante , Machado-Costa Marcela Camara , Marques Wilson , Matsui Jr Ciro , Mendonça Rodrigo Holanda , Nardes Flávia , Oliveira Acary Souza Bulle , Pessoa Andre Luis Santos , Saute Jonas Alex Morales , Sgobbi Paulo , Van der Linden Hélio , Gurgel-Giannetti Juliana
Published: February 2024

Spinal muscular atrophy linked to chromosome 5 (SMA-5q) is an autosomal recessive genetic disease caused by mutations in the SMN1. SMA-5q is characterized by progressive degeneration of the spinal cord and bulbar motor neurons, causing severe motor and respiratory impairment with reduced survival, especially in its more severe clinical forms. In recent years, highly effective disease-modifying therapies have emerged, either acting by regulating the splicing of exon 7 of the SMN2 gene or adding a copy of the SMN1 gene through gene therapy, providing a drastic change in the natural history of the disease. In this way, developing therapeutic guides and expert consensus becomes essential to direct the use of these therapies in clinical practice. This consensus, prepared by Brazilian experts, aimed to review the main available disease-modifying therapies, critically analyze the results of clinical studies, and provide recommendations for their use in clinical practice for patients with SMA-5q. This consensus also addresses aspects related to diagnosis, genetic counseling, and follow-up of patients under drug treatment. Thus, this consensus provides valuable information regarding the current management of SMA-5q, helping therapeutic decisions in clinical practice and promoting additional gains in outcomes.
A Brazilian series utilizing the SMASH-U system for etiologic classification of intracerebral hemorrhage
Authors: Silva Luiz Henrique Libardi , Andrade João Brainer Clares de , Majdoub Ahmad Ali El , Miranda-Alves Maramélia , Valiente Raul Alberto , Rodrigues Daniela Laranja Gomes , Silva Gisele Sampaio
Published: February 2024

Background Understanding the causes of intracerebral hemorrhage (ICH) is crucial for effective treatment and preventing recurrences. The SMASH-U scale is a suggested method for classifying and predicting the outcomes of ICH.

Objective To describe the SMASH-U classification and outcomes by etiology in patients admitted to a comprehensive stroke center in São Paulo, Brazil.

Methods A retrospective analysis was conducted on patients admitted to the hospital or outpatient clinic between April 2015 and January 2018. Two stroke neurologists evaluated the SMASH-U classification, and patients with incomplete medical records were excluded.

Results Out of the 2000 patients with a stroke diagnosis evaluated, 140 were included in the final analysis. The mean age was 57.9 (± 15.5) years, and 54.3% were male. Hypertension was the most frequent etiology, accounting for 41.4% of cases, followed by amyloid angiopathy (18.5%) and structural lesions (14.1%). Structural lesions were more common among women and patients under 45 years old. Favorable outcomes were observed in 61% of patients with structural lesions, compared to 10% of patients with medication-related etiologies.

Conclusion This study provides important evidence regarding the etiological classification of Brazilian patients with ICH. Hypertension and amyloid angiopathy were the most frequent causes, while structural lesions and systemic diseases were more common in younger patients.
An integrative review of missed nursing care and the general practice nurse
Authors: Willis Eileen , Verrall Claire , McInnes Susan , Pate Elyce
Published: February 2024

Background The phenomenon of missed care has received increasing interest over the past decade. Previous studies have used a missed care framework to identify missed nursing tasks, although these have primarily been within the acute care environment. The aim of this research was to identify missed care specific to the role of the general practice nurse. Methods An integrative review method was adopted, using The Mixed Methods Appraisal Tool to assist in a methodological appraisal of both experimental, theoretical, and qualitative studies. Thematic analysis was then used to analyse and present a narrative synthesis of the data. Data sources: CINAHL, SCOPUS, Web of Science and Google Scholar databases were searched between 2011 and 2022 for empirical research that reported missed care and the general practice nurse. Results Of the 787 papers identified, 10 papers met the inclusion criteria. Three themes identified missed care in relation to primary healthcare nurses: under-staffing and resourcing, communication difficulties, and role confusion. Conclusion Isolating missed care by general practice nurses was challenging because much of the research failed to separate out general practice nurses from community and primary health care nurses. This challenge was exacerbated by disparity in the way that a general practice nurse is defined and presented in the various databases. While some themes such as those related to communication and understaffing and resourcing demonstrate some parallels with the acute sector, more research is required to identify missed care specific to the general practice nurse.
DNA hypomethylation ameliorates erosive inflammatory arthritis by modulating interferon regulatory factor-8
Authors: Swarnkar Gaurav , Semenkovich Nicholas P. , Arra Manoj , Mims Dorothy K. , Naqvi Syeda Kanwal , Peterson Timothy , Mbalaviele Gabriel , Wu Chia-Lung , Abu-Amer Yousef
Published: February 2024

Epigenetic regulation plays a crucial role in the pathogenesis of autoimmune diseases such as inflammatory arthritis. DNA hypomethylating agents, such as decitabine (DAC), have been shown to dampen inflammation and restore immune homeostasis. In the present study, we demonstrate that DAC elicits potent anti-inflammatory effects and attenuates disease symptoms in several animal models of arthritis. Transcriptomic and epigenomic profiling show that DAC-mediated hypomethylation regulates a wide range of cell types in arthritis, altering the differentiation trajectories of anti-inflammatory macrophage populations, regulatory T cells, and tissue-protective synovial fibroblasts (SFs). Mechanistically, DAC-mediated demethylation of intragenic 5'-Cytosine phosphate Guanine-3' (CpG) islands of the transcription factor Irf8 (interferon regulatory factor 8) induced its re-expression and promoted its repressor activity. As a result, DAC restored joint homeostasis by resetting the transcriptomic signature of negative regulators of inflammation in synovial macrophages (MerTK, Trem2, and Cx3cr1), T
REGs
(Foxp3), and SFs (Pdpn and Fapα). In conclusion, we found that Irf8 is necessary for the inhibitory effect of DAC in murine arthritis and that direct expression of Irf8 is sufficient to significantly mitigate arthritis.
TNF and IFNγ-induced cell death requires IRF1 and ELAVL1 to promote CASP8 expression
Authors: Deng Buhao , Wang Jingyi , Yang Tingyun , Deng Zhao , Yuan Jiafan , Zhang Bohan , Zhou Zhen , Chen Fang , Fang Lu , Liang Chengzhi , Yan Bo , Ai Youwei
Published: February 2024

TNFα and IFNγ (TNF/IFNγ) synergistically induce caspase-8 activation and cancer cell death. However, the mechanism of IFNγ in promoting TNF-initiated caspase-8 activation in cancer cells is poorly understood. Here, we found that in addition to CASP8, CYLD is transcriptionally upregulated by IFNγ-induced transcription factor IRF1. IRF1-mediated CASP8 and CYLD upregulation additively mediates TNF/IFNγ-induced cancer cell death. Clinically, the expression levels of TNF, IFNγ, CYLD, and CASP8 in melanoma tumors are increased in patients responsive to immune checkpoint blockade (ICB) therapy after anti–PD-1 treatment. Accordingly, our genetic screen revealed that ELAVL1 (HuR) is required for TNF/IFNγ-induced caspase-8 activation. Mechanistically, ELAVL1 binds CASP8 mRNA and extends its stability to sustain caspase-8 expression both in IFNγ-stimulated and in basal conditions. Consequently, ELAVL1 determines death receptors–initiated caspase-8–dependent cell death triggered from stimuli including TNF and TRAIL by regulating basal/stimulated caspase-8 levels. As caspase-8 is a master regulator in cell death and inflammation, these results provide valuable clues for tumor immunotherapy and inflammatory diseases.
Falling liquid droplets discharge
Authors: Liu JiaLin , Nie LanLan , Liu DaWei , Lu XinPei
Published: February 2024

This paper reports the phenomenon of two plasma segments forming when a water droplet descends, one between the upper part of the droplet and the outlet tube and the other between the lower part of the droplet and the water surface in the container. The study reveals that as the water droplet descends, the length of the upper plasma gradually increases, while the length of the lower plasma decreases until the lower plasma disappears upon contact between the water droplet and the water in the container. The study finds that the rotational temperature of this plasma reaches 2100 K, with an electron density of 1014 cm−3. Furthermore, it is intriguing to note that the descent speed of the droplet is significantly greater than that of a freely falling droplet. Further research indicates that this is due to an instant water channel explosion-induced downward impact on the droplet caused by plasma generation at the upper part of the droplet. The advantage of this device lies in the fact that the plasma only comes into direct contact with water, without any contact with metal electrodes, thus eliminating the issue of electrode corrosion. Furthermore, since the water is in dynamic flow, it facilitates the dissolution of reactive gaseous components into the water, making it suitable for applications related to plasma-activated water and similar purposes.
BDS-3 six-frequency precise point positioning: effects of receiver-dependent inter-frequency clock bias and multi-frequency contributions
Authors: Zhang Zhehao , Pan Lin
Published: February 2024

We find that there is time-varying bias at the receiver in BDS-3 multi-frequency phase observations, which will lead to receiver-dependent inter-frequency clock bias (RIFCB) and damage the rigor of BDS-3 multi-frequency precise point positioning (PPP) model. A unified RIFCB correction method compatible with uncombined and ionospheric-free combined PPP models using any BDS-3 frequencies is proposed. The contributions of multi-frequency integration to BDS-3 static and kinematic PPP performance are evaluated. The results indicate that the RIFCB amplitude can reach 1 dm. If the RIFCB correction is ignored, the phase observation residuals present a systematic bias. RIFCB has potential effects on precise time transfer, ionospheric monitoring, and fractional cycle bias estimation. Experimental results show that the long-term frequency stability of time transfer can be improved by correcting RIFCB. The joint use of all BDS-3 six-frequency signals can significantly shorten the convergence time, and the positioning accuracy can also be slightly improved.
Prediction of chlorine residual in effluent based on SSA-SFA-CFBLS for water treatment process parameters
Authors: Wang Cunsong , Han Kaichao , He Wenmin , Zhang Quanling
Published: February 2024

Accurate parameter prediction of chlorine residual in effluent is necessary for nonlinear, long-delayed water treatment process to raise water quality. To improve the prediction model precision and computational efficiency, a cascade broad learning system based on the sparrow search algorithm (SSA) and slow feature analysis (SFA) is proposed in this paper. First, the SFA method is introduced to extract the essential characteristics of water monitoring data as the input of the prediction model. Then, a cascaded broad learning system is adopted to establish a prediction model for residual chlorine in water works effluent. The cascade broad learning can deal well with online prediction. Furthermore, the SSA is utilized to obtain the optimal hyperparameters of the established model, which can avoid the complex and time-consuming manual parameter tuning process. Finally, the comparison experiment with several methods is carried out. The experimental results show that the proposed method saves more computational resources, and its time consumption is only 16.8% of that of the comprehensive deep learning model with basically the same accuracy. The prediction accuracy is improved, and its prediction accuracy is improved by 7.6% on average compared with most traditional deep learning models such as long short term memory (LSTM), recurrent neural network (RNN) and fated recurrent unit (GRU).
Mechanical strength measurement of needle-shaped CaSO4 microcrystals by a three-point bend test
Authors: Nikulin I , Ivanov O , Nikulicheva T , Mishunin M , Vyugin A , Alfimova N , Vyazmin V , Saenko M
Published: February 2024

A simple method for direct measurement of the mechanical strength of needle-shaped microcrystals of calcium sulfate, CaSO4, is proposed. The microcrystals, with a length from 30 to 50 μm and transverse dimensions from 1 to 3 μm, can act as reinforcing filler in various structural and building composites to improve their mechanical properties. The method is based on a three-point bend test, adapted to microscopic objects. The CaSO4 microcrystals were placed on a substrate, which was a twill-weave filter mesh consisting of intertwined steel fibers with diameter of ∼25 μm. Due to the twill weave, the mesh surface is characterized by a periodic distribution of protrusions and depressions. The protrusions act as supports for the placing of microcrystals, and the depressions provide the possibility of deformation and destruction of microcrystals under the action of an increasing vertically acting force, which is applied to the microcrystal through the indenter of the dynamic ultra-micro hardness tester. The moment of destruction of the microcrystals is observed to be dependent on the force on the displacement of the indenter. The measured values of the mechanical strength of CaSO4 microcrystals varied in a range from ∼3.5 to ∼6.0 GPa. The experimental strength values are in good agreement with the values obtained from the results of numerical analysis of the stressed state formed in the volume of CaSO4 microcrystals during the three-point bend test.
Accelerated prediction of stacking fault energy in FCC medium entropy alloys using multilayer perceptron neural networks: correlation and feature analysis
Authors: Mahato Swati , Gurao Nilesh P , Biswas Krishanu
Published: February 2024

A multilayer perceptron neural networks (MLPNN) model is developed for robust and quick prediction of stacking fault energy (SFE) to overcome the challenges faced in the calculation of SFE via experimentation and atomistic calculations in FCC medium entropy alloys (MEA). The present investigation employs a three-step hybrid feature selection approach to obtain a comprehensive understanding of the prominent features that influence the SFE, as well as the interrelationships among these features. The feature space encompasses various features related to composition, lattice stability, and elemental properties, of MEAs. The findings indicate that the estimation of SFE relies on five crucial factors: temperature, lattice stability, specific heat, ionization energy, and Allen electronegativities. Furthermore, a mathematical relationship for the estimation of the SFE is derived, considering the various influencing and prominent factors. Consequently, the MLPNN model for robust SFE prediction in MEAs is developed and the performance is evaluated using R
2 scores, with values of 0.87 and 0.85 obtained for the training and testing datasets, respectively. This efficient strategy introduces a novel opportunity for the engineering of SFE in the extensive range of alloy chemistry of MEAs, enabling the quick prediction of SFE, and facilitating the systematic exploration of new alloys for the development of mechanisms that may accommodate deformation through octahedral/partial slip, twinning, and/or transformation.
Caralluma pauciflora based Ag-NPs activate ROS - induced apoptosis through down-regulation of AKT, mTOR and pI3K signaling in human gastric cancer (AGS) cells
Authors: Navaneethan Renuga Devi , N C J Packia Lekshmi , Ramaiah Mariselvam , Ravindran Rajeswari , T Ananth Kumar , Chinnathambi Arunachalam , Ali Alharbi Sulaiman , Sivagnanam Ananthi , Mohemedibrahim Ponnani Kaja Mideen
Published: February 2024

The phytochemicals found in Caralluma pauciflora were studied for their ability to reduce silver nitrate in order to synthesise silver nanoparticles (AgNPs) and characterise their size and crystal structure. Thunbergol, 1,1,6-trimethyl-3-methylene-2-(3,6,9,13-tetram, Methyl nonadecanoate, Methyl cis-13,16-Docosadienate, and (1R,4aR,5S)-5-[(E)-5-Hydroxy-3-methylpent were the major compounds identified in the methanol extract by gas chromatography–mass spectrum analysis. UV/Vis spectra, Fourier-transform infrared spectroscopy, x-ray diffraction, scanning electron microscope with Energy Dispersive Xâray Analysis (EDAX), Dynamic Light Scattering (DLS) particle size analyser and atomic force microscope (AfM) were used to characterise the Caralluma pauciflora plant extract-based AgNPs. The crystal structure and estimated size of the AgNPs ranged from 20.2 to 43 nm, according to the characterization data. The anti-cancer activity of silver nanoparticles (AgNPs) synthesised from Caralluma pauciflora extract. The AgNPs inhibited more than 60% of the AGS cell lines and had an IC50 value of 10.9640.318 g, according to the findings. The cells were further examined using fluorescence microscopy, which revealed that the AgNPs triggered apoptosis in the cells. Furthermore, the researchers looked at the levels of reactive oxygen species (ROS) in cells treated with AgNPs and discovered that the existence of ROS was indicated by green fluorescence. Finally, apoptotic gene mRNA expression analysis revealed that three target proteins (AKT, mTOR, and pI3K) were downregulated following AgNP therapy. Overall, the findings imply that AgNPs synthesised from Caralluma pauciflora extract could be used to treat human gastric cancer.
Strong convergence of the vorticity and conservation of the energy for the α-Euler equations
Authors: Abbate Stefano , Crippa Gianluca , Spirito Stefano
Published: February 2024

In this paper, we study the convergence of solutions of the α-Euler equations to solutions of the Euler equations on the two-dimensional torus. In particular, given an initial vorticity ω
0 in

L
x
p

for

p
∈
(
1
,
∞
)

, we prove strong convergence in

L
t
∞

L
x
p

of the vorticities q

α
, solutions of the α-Euler equations, towards a Lagrangian and energy-conserving solution of the Euler equations. Furthermore, if we consider solutions with bounded initial vorticity, we prove a quantitative rate of convergence of q

α
to ω in Lp
, for

p
∈
(
1
,
∞
)

.
Work and energy during a head-on collision
Authors: Cross Rod
Published: February 2024

When two balls collide head-on in an elastic collision, the work done on each ball by the impact force is equal to the change in kinetic energy of each ball. A calculation of the work done during the collision is presented as an interesting extension of the work-energy principle, including an example where one of the balls is infinitely heavy.
Why every observatory needs a disco ball
Authors: Cumming Robert J , Pietrow Alexander G M , Pietrow Livia , Cavallius Maria , Petit dit de la Roche Dominique , Pietrow Casper , Schroetter Ilane , Skan Moa
Published: February 2024

Commercial disco balls provide a safe, effective and instructive way of observing the Sun. We explore the optics of solar projections with disco balls, and find that while sunspot observations are challenging, the solar disk and its changes during eclipses are easy and fun to observe. We explore the disco ball’s potential for observing the moon and other bright astronomical phenomena.
Investigating the beliefs of experts on teaching quantum physics at secondary schools: key concepts, topics, and fundamentals
Authors: Onorato P , Mauro M Di , Malgieri M
Published: February 2024

This study presents the findings of a series of interviews conducted with 17 Italian academic experts in the field of physics. The interviews aimed at exploring various aspects of teaching quantum physics (QP) at the secondary school level. The focus was on evaluating the overall suitability of teaching QP, the benefit of introducing it with an historical approach, the necessary mathematical grounds, as well as foundational and controversial aspects, along with the topics that should be included in the curriculum. Based on the insights gathered from the interviews, a questionnaire was formulated and administered to 31 additional experts, with the primary objective of exploring the experts’ perspectives on whether QP should be included in secondary school curricula and the underlying reasons for their stance. Indeed, some of the scholars argue that teaching QP is crucial as it contributes to the promotion of scientific literacy, considering QP as one of the most significant cultural advancements in science over the past centuries. On the other hand, some experts believe that the emphasis should be placed on informing and educating society about quantum technologies and upcoming technological advancements. The second objective of this questionnaire was to further deepen the investigation into the key subjects that specialists deem essential for teaching at the secondary level. The results revealed a consensus among the experts regarding the concepts that hold significant importance, namely atomic energy levels and quantisation, particle behaviour of light, Heisenberg’s uncertainty principle, and probability, and regarding the examples, i.e. the photoelectric effect, spectral lines, and the double slit experiment. The last objective of the questionnaire was to address foundational and controversial aspects of QP that are relevant to high school curricula. This entailed examining the consensus among experts regarding their perspectives on the view of these topics. Lack of such consensus emerged.
Harnessing the potential of NiMn2O4 nanoparticle: a next-generation supercapacitor electrode material
Authors: Shariq Mohammad , Alzahrani Ali , Almutib Eman , Alharbi Abdulrahman F , Algarni Saud A , Almashnowi Majed Y A , Bouzgarrou Souhail Mohammed , Ghaly Waleed A , Ali Syed Kashif , Hassan K F
Published: February 2024

This research addresses the pressing demand to enhance energy density and power in energy storage devices, including batteries, fuel cells, and supercapacitors. Here, NiMn2O4 is synthesized using the urea combustion method. Characterization techniques, including powder x-ray diffraction, field emission scanning electron microscopy, and BET analysis, are employed to investigate its properties. The diffraction peaks showed that NMO had a face-centered tetragonal structure, and the Scherrer equation was used to figure out the average crystallite size (t) as 8.73 nm. Its electrochemical behavior is extensively evaluated through cyclic voltammetry and galvanic charge–discharge measurements. The findings indicate that the fabricated NiMn2O4 electrodes exhibited remarkable specific capacitance and exceptional cycling stability, retaining 97% of their initial performance over 10000 cycles. The specific capacitance of the electrode from GCD was obtained 80 F g−1 at a current density of 0.25 A g–1. This study highlights the potential of NiMn2O4 as an electrode material for high-performance electrochemical supercapacitors, offering a viable solution for advancing energy storage technologies.
Analytical expression of negative differential thermal resistance in a macroscopic heterojunction
Authors: Kobayashi Wataru
Published: February 2024

Heat flux (J) generally increases with temperature difference in a material. A differential coefficient of J against temperature (T) is called differential thermal conductance (k), and an inverse of k is differential thermal resistance (r). Although k and r are generally positive, they can be negative in a macroscopic heterojunction with positive T-dependent interfacial thermal resistance (ITR). The negative differential thermal resistance (NDTR) effect is an important effect that can realize thermal transistor, thermal memory, and thermal logic gate. In this paper, we examine analytical expressions of J, k, r, and other related quantities as a function of parameters related to thermal conductivity (κ) and ITR in a macroscopic heterojunction to precisely describe the NDTR effect.
Analysis of Fracture Initiation Pressure of Tight Sandstone in HangJinQi
Authors: Zhang Junyi
Published: February 2024

Simply increasing the fracture length to enhance the conductivity of the reservoir has limited success in increasing the production rate, thus hampering the pace of production at Hangjinqi. To combat this problem, a mathematical model was developed to determine the onset pressure of tight sandstone in Hangjinqi based on the Mohr-Coulomb criterion. It is shown that the onset angle decreases with increasing trap inclination, thus making it difficult to close the fracture with high horizontal pressure and suction. As for the block, it is one of Sinopec’s major areas for developing tight, low-permeability oil and gas in the Ordos Basin. To address this issue, a mathematical model was developed for the onset pressure of tight sandstone in Hangjinqi, taking into account factors such as vertical principal stress, maximum horizontal principal stress, minimum horizontal principal stress, and fracture inclination.The case of trap HE1 in JPH-416 was solved using a minimal bisection method, showing that the onset angle increases with trap inclination. As the fracture inclination increases, the fracture closure pressure gradually increases, and the effect of the minimum horizontal and vertical principal stresses becomes more pronounced.
A Study on Mechanism of Evaporation Reduction of Desulfurization Wastewater in Air Cooling Tower
Authors: Du Ying , Li Lujun , Song Xiaojun , Wang Fei
Published: February 2024

It’s a new technology for the concentration and reduction of desulfurization wastewater by the indirect air cooling tower. In this paper, indoor experiments are conducted to explore the evaporation characteristics of the evaporation tower and the evaporation law of desulfurization wastewater in the filler and analyze the factors affecting the evaporation characteristics, and a power plant adopting this technology is tested to verify the conclusion of the indoor experiments. The results show that the evaporation rate of the evaporation tower is positively correlated with the cross-sectional wind speed, water spray density, packing height and other parameters, and the influence of the interrupted wind speed on the evaporation rate is the most significant. The difference of vapor pressure has a positive linear relationship with that of mass fraction of the air in inlet and outlet, and the results of model test conform to those of actual one basically. On the condition of ventilation rate of 817.56m3/s, the evaporation efficiency of a mechanical ventilation cooling tower with a drenching area of about 400m2 can reach 16.2-18.4t/h, which basically meets the engineering needs of desulfurization wastewater concentration and reduction in millions of thermal power plants.
Comparative Testing the Uncertainty of A/D Converters in A Hot-Wire Anemometer Measurement Using Grid-Generated Turbulence
Authors: Yamaguchi Hiroto , Suzuki Hiroki , Kouchi Toshinori
Published: February 2024

This study investigates the uncertainty of the A/D converter when measuring multi-scale turbulence fluctuations using a hot-wire anemometer. The flow is generated in a low-speed wind tunnel, the turbulence is generated by a turbulence grid and the fluctuations are measured. A compact hot-wire anemometer was used and a high accuracy A/D converter was introduced for the measurements. Methods to minimise the influence of noise were also incorporated and measurements were carried out in two situations, one with and one without turbulence. The experimental results showed that measurements under a specific condition (Case 1 in this study) had the sufficienty reproducibility of turbulence fluctuations and the least effect of noise. The results showed that the high frequency characteristics of the turbulence could also be accurately measured under this condition. In conclusion, it is clear that the choice of a suitable A/D converter and the optimisation of the measurement environment are critical for turbulence measurements with a hot-wire anemometer.
Assessing OpenFOAM-based Large-eddy Simulation Using Decay Characteristics of An Isotropic Taylor-green Vortex
Authors: Ono Akira , Chitose Makoto , Suzuki Hiroki , Kouchi Toshinori
Published: February 2024

The aim of this study is to investigate OpenFOAM using isotropic TGV flows. The main focus is on the establishment of energy conservation laws, in particular using inviscid fields to assess energy constancy; Large-Eddy Simulation (LES) is applied and the results are compared with those obtained using spectral methods; unlike previous studies of OpenFOAM, this study uses an unsteady turbulent TGV flow. The computational methods used are a central difference method, a PISO algorithm and a Smagorinsky model. The study revealed errors in the conservation of kinetic energy in the OpenFOAM analysis. In particular, the energy decay was significant at high spatial resolution, confirming the different turbulence energy decay characteristics of DNS and OpenFOAM. However, when the model constant was 0.6, the decay characteristics were shown to be in good agreement with DNS.
Study on Smoke Spreading Characteristics of Highway Tunnel Fire
Authors: Yu Xuehui , Wang Chao , Cui Xue , Han Jinxin , Sun Xiaolin
Published: February 2024

In the event of a fire in a road tunnel, the effect of natural smoke exhaust alone is far inferior to that of mechanical smoke exhaust. Study of the characteristics of the flux of smoke gases inside the tunnel with the use of mechanical exhausts in case of sudden fire in road tunnels by means of specific model simulation methods, specific analysis by setting fixed exhaust spacing and different emission volumes, and the addition of fine water mist is studied. The results show that: when the exhaust vent spacing is 30m, the smoke exhaust volume in 30m³/s, 40m³/s, 50m³/s mechanical smoke exhaust device under the action of temperature, CO concentration and visibility will not affect the safe evacuation of the personnel, but taking into account the control of smoke propagation and economic reasonableness, the smoke exhaust volume of 40m³/s is better than the smoke exhaust volume of 30m³/s and 50m³/s. Under the coupling effect of mechanical smoke exhaust system and fine water mist, the spread of smoke in the tunnel can be controlled within a certain range and the internal temperature of the tunnel can be reduced. It can provide a certain basis for the design of the exhaust vent and the setting of water mist in the future.
Water Based Mn-Zn Magnetic Fluid Heat Dissipation Capacity Testing Platform
Authors: Tang Zhen , Zhao Zhilong , Zhao Ke , He Junbo , Hu Yangguang , Xue Yuqing , Huang Shengli , Feng Yali
Published: February 2024

Manganese zinc magnetic fluid is a temperature sensitive magnetic fluid that can regulate its flow behavior using temperature and magnetic fields. However, there is currently no testing platform for evaluating the heat dissipation ability of this magnetic fluid working fluid by coupling temperature and magnetic fields. This article establishes two experimental testing platforms for applying magnetic fields, namely a circulating pipeline and a temperature equalization plate. Compared with deionized water, evaluate the average temperature and heat dissipation ability of water-based manganese zinc magnetic fluid. The test results show that the heat dissipation start time of the manganese zinc magnetic fluid loop pipe is better than that of deionized water. Under the action of magnetic field (500Gs), the average temperature of the circulating pipeline decreases by 7.2% (heat source power 15W); Under the action of a magnetic field (3000Gs), the thermal resistance of the homogenizing plate (filled with 48% water-based manganese zinc magnetic fluid) decreases by about 16.7% (heat source power 140W). The water-based manganese zinc magnetic fluid working fluid exhibits better heat transfer performance than the deionized water working fluid under high heat source power. The experimental results prove that the designed water-based manganese zinc magnetic fluid working fluid heat dissipation capacity testing platform has reliable experimental quantification results.
Research and Analysis on the Optimization of the Preventive Disassembly Inspection Intervals of Important Wedge Gate Valves in the Primary Cooling System of CPR1000 Nuclear Power Plant
Authors: Yang Lifei , An Daqi , Li Guangyu , Zhou Jun , You Xiaoyou , Cao Guanghui
Published: February 2024

At present, the important wedge gate valve of the primary coolant system of the CPR1000 nuclear power plant performs preventive disassembly inspection according to the intervals of 5 years, the average dose of a single disassembly is about 10mSv, the average time of each overhaul occupies the critical path is 1 hour, and the valve has been disassembly inspection in good condition. Based on the historical maintenance data, operating environment, failure mode, failure mechanism, operation and maintenance experience feedback of the same type of valve, and failure risk control of the important wedge gate valve of the primary coolant system, this paper demonstrates and analyzes the feasibility of extending the disassembly inspection intervals of the important wedge gate valve of the primary coolant system from 5 years to 10 years. This work plays an important role in improving the economic efficiency of nuclear power plant maintenance and reducing the radiation dose of maintenance.
Experimental Study on Non-contact Labyrinth Seal under Negative Pressure Intervention
Authors: Wu Luji , Sun Yibo , Li Kunlong , Yang Linjie , Chen Junhao , Wang Jingyuan
Published: February 2024

The non-contact labyrinth seal structure of a high-speed gearbox was taken as the research object, a non-contact labyrinth seal structure under negative pressure intervention was designed, and its rationality was verified by simulation analysis. An airfoil-shaped acquisition device for collecting negative pressure was designed, and its rationality was analyzed by simulation. According to the design, a test platform for non-contact labyrinth seal under negative pressure intervention was built to measure the pressure data of each sealing chamber of the non-contact labyrinth seal under different working conditions. The results showed that it was effective to balance the internal and external pressure of the non-contact labyrinth seal by using the negative pressure collected by the airfoil-shaped device in the complex flow field of the high-speed gearbox. It also showed that the non-contact labyrinth seal structure under negative pressure intervention designed in this paper is an effective way to solve the leakage problem of the non-contact labyrinth seal used in high-speed gearbox.
Influence of Shape, Installation and Rotation Motion Errors on Tin Bronze Clearance Seal of Rotary Joint
Authors: Jia Xingyun , Li Kening , Liu Chunrui , Zhang Le , Chen Tao
Published: February 2024

The rotary joint is the key device of the marine clutch. Once the seal fails, the power cannot be transmitted. In view of the above problems, this research studies the influence of shape, installation and rotation motion errors on clearance seal. The results show that compared with the absence of roundness error, the roundness error of the shaft will increase the leakage by about 2.5-4.9 %. The cylindrical error of the bushing will reduce the leakage, but it will bring more serious friction, wear and life problems. The existence of radial installation error will increase the leakage, and the larger the radial installation error, the more obvious the flow field extrusion, the higher the unevenness of the pressure field in the whole flow field. The existence of angular installation error will reduce the leakage, but it will cause more serious friction and wear, resulting in a sharp increase in temperature. The leakage increases by about 0.68 % when the radial installation error is 0.1 mm, and the rotary motion error further increases the leakage by about 0.15 %. The above research can provide theoretical support for the structural design and optimization of the rotary joint tin bronze clearance seal.
Optimization Design of Mining Tri-cone Bit Air Nozzle by CFD
Authors: Yan Lili , Wang Qiaozhu , Tang Jingran , Dong Xuelian , Chen Lusi , Song Runquan
Published: February 2024

Performance of the air nozzle of the mine tri-cone bit directly affects life of bit and rock breaking efficiency. The shape of air nozzle influences performance of mine tri-cone bit. It is necessary to optimize the shape of the air nozzle of tri-cone drill bits. The general specifications of gas mine tri-cone bit were analysed. Working condition and parameters of the air nozzle of the mine tri-cone bit were determined. A three-dimensional model of the air nozzle of the mine tri-cone bit was established. The characteristic geometry and range of air nozzle were determined. The performance index of air nozzle was proposed. An orthogonal experiment table of characteristic geometry of air nozzle was established. The ranking of influence weights of characteristic geometry was obtained. Key characteristic geometry which affects the performance of air nozzle was also obtained. This thesis work helps to improve the working performance of the gas nozzle of the three-cone bit. It can provide some reference ideas for the optimized design of the cone bit
Fracture Failure Analysis of a 5-7/8” Drill Pipe Pin Joint in an Ultra-deep Gas Well
Authors: Ji Nan , Wang Peng , Feng Chun , Zhu Lijuan
Published: February 2024

In recent years, the frequency of drill pipe failure accidents has increased during ultra-deep well drilling process. The fracture failure of pin joint of a 5-7/8” drill pipe happened in an ultra-deep gas well after thirty-five hours’ service. Failure causes were investigated by physical and chemical properties test of the material, macro and micro feature analysis of the fracture surface. The results showed that the physical and chemical properties of the drill pipe were all satified the corresponding standard requirements, the fracture of mode of the dill pipe is fatigue fracture, which was attributed to the harsh load condition during the reaming operation. Furthermore, the increased inner diameter of the pin joint also gives an acceleration of the fatigue fracture process.
Surface Analysis and Optimization of Large Aperture Mirror Supported by Elastic Expansion Sleeves
Authors: Zhang Jinsong , Zhang Zhiming , Fan Quantang
Published: February 2024

In order to meet the stability of the support structure of arrayed large aperture mirror and improve the surface accuracy of the mirror, the elastic expansion sleeve is proposed as the back-support structure of the large aperture mirror. The feasibility of the support method is verified by theoretical analysis and experiment. The PV value of additional wavefront distortion is about 75.3nm<λ/5(λ=632.8nm) when the torque of single mandrel screw is 40N·cm, which meets the technical specifications. The change trend of the support-induced surface is compared between the finite element simulation and the measured results under different mandrel screw torque conditions. When the support torque is increased in equal increments, there is a linear positive correlation between the PV value of support-induced surface and the support torque. Based on the change trend of the support-induced surface, the optimization design scheme of the initial surface is proposed. And the simulation results show that the optimized induced distortion is smaller than that of the ideal surface (the compensation ratio is 7.68%), which reduces the additional wavefront distortion under the actual mounting support.
Creep Analysis and Material Properties Research of Rotary Calciner
Authors: Cheng Yanmei , Zhang Hua , Ye Guoan , Hong Ye
Published: February 2024

Unavoidably, during the aqueous reprocessing of spent fuel, high level liquid waste is produced, which is typically vitrified. A rotary calciner is an essential component of a two-step cold crucible melter equipment system. Owing to the calciner’s long-term operation under high temperature condition, potential effects from metal creep are essential design factors. Stable temperature and stress fields of components of a rotary calciner have been calculated based on the finite element analysis software ANSYS. Furthermore, creep life of creep effects has been evaluated and comparisons among Inconel 690, Inconel625, and SUS 310s tubes’ mechanical property performance have been conducted. The results indicate that all three materials require the mechanical property requirements and SUS 310s exhibits the minimum creep displacement.
Test Data Evaluation of Very High Cycle Fatigue Based on Maximum Likelihood Method
Authors: Zhang Ying , Zhang Chengcheng , Sun Kai , Xu Heming
Published: February 2024

The very high cycle fatigue tests of TC4 alloy were accomplished through ultrasonic fatigue experiment which were conducted on the ultrasonic fatigue testing system at frequency range of 20000 ±1000 Hz. In contrast to the commonly used Basquin model, a Maximum Likelihood Method to fit the three-parameter nonlinear model was used to verify the adaptability in very high cycle fatigue regime. These two methods were used to estimate S-N curves of three types of materials which were TC4 alloy, GH4169 alloy and TC17 alloy in the very high cycle fatigue regime and the results were compared with test data. The evaluation result of the MLM model based on the three-parameter nonlinear model shows a good agreement with test data. The mean and variance of relative error of the MLM model are less than those of the Basquin model, providing a suitable evaluation method for predicting very high cycle fatigue limit which often has higher scatter.
Physical Simulation of Medium and Low Temperature Rolling of Mg-Li Alloy Sheet
Authors: Fu Yida , Li Jun , Li Jiacheng , Peng Weijian , Hu Shuhua , Liu Junwei
Published: February 2024

In this paper, LZ91 magnesium-lithium alloy was taken as the research object. At the rolling temperature of room temperature and 453 K, the plane strain compression physical simulation experiment was carried out on the sample with one pass reduction of 15 % and three passes total reduction of 45 %. After each pass of rolling, the sample was annealed at 503 K for 30 min. Then the effects of different treatment processes on the microstructure of LZ91 magnesium-lithium alloy were studied by metallographic microscope, X-ray diffractometer and scanning electron microscope. The results show that under the same strain, the stress of room temperature rolling is larger than that of 453 K rolling; with the increase of annealing passes, the effect of work hardening gradually weakened. With the increase of rolling amount, the original mechanically mixed ' α ' phase and ' β ' phase will deform along the deformation direction, showing a streamline shape. Rolling at 453 K, the diffraction peak of the sample with 45 % total reduction of three passes changes the most.
A Novel Coupled State/Load/Parameter Identification Method Based on the Improved Particle Filter Algorithm
Authors: Wang Ting , Wan Zhimin , Xie Xuefei
Published: February 2024

There have been increasing research studies focusing on the identification of structural load with uncertain model in recent years. This paper presents a novel approach based on the improved Particle Filter (PF) algorithm for the nonlinear structural system. The main strategy of the approach is the fusion of the weighted least-square algorithm and the conventional PF algorithm. The weighted least-square algorithm is derived for the estimation of the unknown loads, and the PF algorithm is used for the identification of the augmented states which includes the structural displacement, velocity and unknown parameters. Additionally, the parallel algorithm is adopted for the improvement of computing speed, and a resampling step is also used for alleviating the degeneracy of the particles to improve the accuracy. A numerical example modelling as a four-story hysteretic shear-beam building is studied to validate the capability of the presented approach.
A Model Based on CNN-LSTM for the Remaining Life Prediction of Equipment in Aircraft Assembly Pulsation Production Line
Authors: Liu Xiongying , Xiao Junjie , Wang Hongfeng , Zhao Zizhao , Liang Biao
Published: February 2024

The aircraft assembly pulsation production line is an advanced and efficient assembly method widely used in aircraft manufacturing. However, equipment malfunctions would occur and can disrupt production takt, affecting the production efficiency. Therefore, accurately predicting the remaining useful life (RUL) of equipment is very crucial. To meet the requirements of both prediction accuracy and efficiency for RUL model used in aircraft pulsation production line, this work proposed a model combining convolutional neural network (CNN) and long short-term memory (LSTM) for RUL prediction. Optimization was performed for the number of neurons in the proposed model with genetic algorithm (GA) to regulate the prediction accuracy and efficiency. Two public datasets representing typical equipment in the pulsation production line were used to validate the proposed model. The results show that the proposed model outperforms the traditional model with substantial improvements in the fitness function of 19.8%, and 30.2% for the two testing datasets. These findings demonstrate the effectiveness of the proposed model in enhancing the accuracy and efficiency of RUL prediction.
Experimental Study on the Quantitative Relationship between the Non-contact Magnetic Signal and Detection Height of Ferromagnetic Pipelines
Authors: He Tengjiao , Tang Jing , Liao Jun , Chen Lujie , Tang Jian , Xia Guoqiang
Published: February 2024

The non-contact magnetic detection technology has good application prospects in the detection of buried steel pipelines. However, the variation of non-contact magnetic signal and measured height is unknown. The application of the technology in pipeline burial inspection is restricted. Therefore, this article conducts non-contact magnetic signal experimental testing on full-size steel pipelines. The collection method, pipe diameter, internal pressure, measurement height, and the non-contact magnetic signal are quantitatively analyzed. And the propagation factor f
G was defined to quantify the degree of influence of measurement height on the non-contact magnetic signal. The results indicate that when the measurement height increases from 0.1 m to 2.0 m, the variation amplitude of the magnetic gradient modulus obtained by the parallel acquisition method is the largest, with a change rate of - 0.35. The amplitude and linear rate of change of the propagation factor f
G increase with the pipe diameter and internal pressure. The amplitude and linear rate of change of the propagation factor f
G increase with the pipe diameter and internal pressure. In the range of pipe diameters from 355.6 mm to 1016 mm, the amplitude of f
G variation is 0.53, and the rate of change is 0.26. Furthermore, the amplitude of f
G change due to a unit increase in internal pressure is 0.022, with a corresponding rate of change of 0.0114.